ArticleLiterature Review

Dietary Choline Deficiency causes DNA Strand Breaks and Alters Epigenetic Marks on DNA and Histones

Authors:
To read the full-text of this research, you can request a copy directly from the author.

Abstract

Dietary choline is an important modulator of gene expression (via epigenetic marks) and of DNA integrity. Choline was discovered to be an essential nutrient for some humans approximately one decade ago. This requirement is diminished in young women because estrogen drives endogenous synthesis of phosphatidylcholine, from which choline can be derived. Almost half of women have a single nucleotide polymorphism that abrogates estrogen-induction of endogenous synthesis, and these women require dietary choline just as do men. In the US, dietary intake of choline is marginal. Choline deficiency in people is associated with liver and muscle dysfunction and damage, with apoptosis, and with increased DNA strand breaks. Several mechanisms explain these modifications to DNA. Choline deficiency increases leakage of reactive oxygen species from mitochondria consequent to altered mitochondrial membrane composition and enhanced fatty acid oxidation. Choline deficiency impairs folate metabolism, resulting in decreased thymidylate synthesis and increased uracil misincorporation into DNA, with strand breaks resulting during error-prone repair attempts. Choline deficiency alters DNA methylation, which alters gene expression for critical genes involved in DNA mismatch repair, resulting in increased mutation rates. Any dietary deficiency which increases mutation rates should be associated with increased risk of cancers, and this is the case for choline deficiency. In rodent models, diets low in choline and methyl-groups result in spontaneous hepatocarcinomas. In human epidemiological studies, there are interesting data that suggest that this also may be the case for humans, especially those with SNPs that increase the dietary requirement for choline.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the author.

... Choline metabolism is closely related to that of different B vitamins and methionine. The pathways of choline and one-carbon metabolism intersect at the formation of methionine from homocysteine [6,7]. Methionine is regenerated (re-methylated) from homocysteine in a reaction catalyzed by betaine homocysteine methyl transferase, in which betaine, a metabolite of choline, serves as the methyl donor [5,[8][9][10]. ...
... Methionine is regenerated (re-methylated) from homocysteine in a reaction catalyzed by betaine homocysteine methyl transferase, in which betaine, a metabolite of choline, serves as the methyl donor [5,[8][9][10]. Choline is an essential nutrient officially established by the Institute of Medicine and is required for several physiological functions [6,11]. Betaine donates a methyl group to Hcy, for the formation of methionine which is converted to SAM, an important methyl donor. ...
... At a periconceptional stage, choline prevents neural tube defects (congenital disabilities of the brain, spinal cord or spine). At the pregnancy/prenatal period, choline aids proper brain and memory formation and maternal placental and liver function and protects the fetus from environmental abuse such as alcohol that could lead to abnormalities in behavior, organ structures, fetal loss and congenital disability [6,7,13]. Additionally, in premenopausal women and men, choline prevents subclinical organ dysfunction such as fatty liver, and liver and muscle damage [6,7]. ...
Article
Full-text available
Choline is an officially established essential nutrient and precursor of the neurotransmitter acetylcholine. It is employed as a cholinergic activity marker in the early diagnosis of brain disorders such as Alzheimer's and Parkinson's disease. Low levels of choline in diets and biological fluids, such as blood plasma, urine, cerebrospinal and amniotic fluid, could be an indication of neurological disorder, fatty liver disease, neural tube defects and hemorrhagic kidney necrosis. Meanwhile, it is known that choline metabolism involves oxidation, which frees its methyl groups for entrance into single-C metabolism occurring in three phases: choline oxidase, betaine synthesis and transfer of methyl groups to homocysteine. Electrocatalytic detection of choline is of physiological and pathological significance because choline is involved in the physiological processes in the mammalian central and peripheral nervous systems and thus requires a more reliable assay for its determination in biological, food and pharmaceutical samples. Despite the use of several methods for choline determination, the superior sensitivity, high selectivity and fast analysis response time of bioanalytical-based sensors invariably have a comparative advantage over conventional analytical techniques. This review focuses on the electrocatalytic activity of nanomaterials, specifically carbon nanotubes (CNTs), CNT nanocomposites and metal/metal oxide-modified electrodes, towards choline detection using electrochemical sensors (enzyme and non-enzyme based), and various electrochemical techniques. From the survey, the electrochemical performance of the choline sensors investigated, in terms of sensitivity, selectivity and stability, is ascribed to the presence of these nanomaterials.
... Human choline deficiency is associated with increased DNA strand breaks and tissue (liver and muscle) dysfunction (57). Choline and its metabolites are recognized as having multiple roles in maintaining cell membrane structural integrity, nerve impulse transmission, cell signaling and lipid transport, and metabolism. ...
... In the state of choline deficiency, the leakage of reactive oxygen species (ROS) from mitochondria is increased due to mitochondrial membrane damage. Choline deficiency leads to an alteration in DNA methylation, which consequently alters gene expressions for genes critically involved in MMR and thereby contributes to an increased cancer risk (57). Male Fischer rats fed a choline and methionine-deficient diet without carcinogen treatment developed preneoplastic hepatocyte nodules in 100% of cases and a 51% incidence of hepatocellular carcinoma (58). ...
Article
Full-text available
The percentage of elderly people with associated age-related health deterioration, including cancer, has been increasing for decades. Among age-related diseases, the incidence of cancer has grown substantially, in part because of the overlap of some molecular pathways between cancer and aging. Studies with model organisms suggest that aging and age related conditions are manipulable processes that can be modified by both genetic and environmental factors, including dietary habits. Variations in genetic backgrounds likely lead to differential responses to dietary changes and account for some of the inconsistencies found in the literature. The intricacies of the aging process, coupled with the interrelational role of bioactive food components on gene expression, make this review a complex undertaking. Nevertheless, intriguing evidence suggests that dietary habits can manipulate the aging process and/or its consequences and potentially may have unprecedented health benefits. The present review focuses on 4 cellular events: telomerase activity, bioenergetics, DNA repair, and oxidative stress. These processes are linked to both aging and cancer risk, and their alteration in animal models by selected food components is evident.
... In the large intestine, choline is metabolized to TMA by the gut microbiota prior to absorption [20,21]. After absorption, TMA is metabolized to trimethylamine-N-oxide (TMAO) by flavin monooxygenases in the liver [22]. is the precursor of the universal methyl donor, S-adenosyl methionine (SAM), which is involved in several methylation reactions, such as epigenetic regulation of DNA as well as the synthesis of phosphatidylcholine [29,30]. As for betaine, dimethylglycine synthesis occurs primarily in the liver and kidney [31][32][33], and further demethylation of dimethylglycine produces sarcosine, which is subsequently metabolized to glycine, resulting in a carbon unit transferred to the folate pool [34]. ...
... The BHMT accounts for up to half of the hepatic homocysteine re-methylation activity [28]. Methionine is the precursor of the universal methyl donor, S-adenosyl methionine (SAM), which is involved in several methylation reactions, such as epigenetic regulation of DNA as well as the synthesis of phosphatidylcholine [29,30]. As for betaine, dimethylglycine synthesis occurs primarily in the liver and kidney [31][32][33], and further demethylation of dimethylglycine produces sarcosine, which is subsequently metabolized to glycine, resulting in a carbon unit transferred to the folate pool [34]. ...
Article
Full-text available
Choline, an essential dietary nutrient for humans, is required for the synthesis of the neurotransmitter, acetylcholine, the methyl group donor, betaine, and phospholipids; and therefore, choline is involved in a broad range of critical physiological functions across all stages of the life cycle. The current dietary recommendations for choline have been established as Adequate Intakes (AIs) for total choline; however, dietary choline is present in multiple different forms that are both water-soluble (e.g., free choline, phosphocholine, and glycerophosphocholine) and lipid-soluble (e.g., phosphatidylcholine and sphingomyelin). Interestingly, the different dietary choline forms consumed during infancy differ from those in adulthood. This can be explained by the primary food source, where the majority of choline present in human milk is in the water-soluble form, versus lipid-soluble forms for foods consumed later on. This review summarizes the current knowledge on dietary recommendations and assessment methods, and dietary choline intake from food sources across the life cycle.
... Consistent with a previous report, as choline demand increases in tumor tissues, blood choline levels drop, leading to decreased urinary choline in CRC patients [27]. Another plausible explanation for decreased urinary choline levels might be its utilization as an alternative methyl group donor for DNA methylation and synthesis in tumor cells [28]. Additionally, levels of the choline precursor, creatinine, were decreased in CRC patient urine samples [29]. ...
Article
Full-text available
Better early detection methods are needed to improve the outcomes of patients with colorectal cancer (CRC). Proton nuclear magnetic resonance spectroscopy (¹H-NMR), a potential non-invasive early tumor detection method, was used to profile urine metabolites from 55 CRC patients and 40 healthy controls (HCs). Pattern recognition through orthogonal partial least squares-discriminant analysis (OPLS-DA) was applied to ¹H-NMR processed data. Model specificity was confirmed by comparison with esophageal cancers (EC, n=18). Unique metabolomic profiles distinguished all CRC stages from HC urine samples. A total of 16 potential biomarker metabolites were identified in stage I/II CRC, indicating amino acid metabolism, glycolysis, tricarboxylic acid (TCA) cycle, urea cycle, choline metabolism, and gut microflora metabolism pathway disruptions. Metabolite profiles from early stage CRC and EC patients were also clearly distinguishable, suggesting that upper and lower gastrointestinal cancers have different metabolomic profiles. Our study assessed important metabolomic variations in CRC patient urine samples, provided information complementary to that collected from other biofluid-based metabolomics analyses, and elucidated potential underlying metabolic mechanisms driving CRC. Our results support the utility of NMR-based urinary metabolomics fingerprinting in early diagnosis of CRC.
... Choline is essential component of the human diet that is necessary for synthases of acetylcholine, membrane and signalling phospholipid, and functions as important methyl donor (Awwad, Geisel, & Obeid, 2012). A few studies observed positive association between the dietary choline intake or plasma concentration and risk of some types of cancer (Xu et al., 2009;Zeisel, 2012). The recommended daily requirement for choline has been set to 550 mg/day and 425 mg/day for non-pregnant women. ...
Article
To establish environmentally friendly polyphenolic extracts from grape and olive pomace, natural deep eutectic solvents (NADES) were used coupled with alternative energy sources – ultrasound and microwave irradiation. Obtained extracts were characterized by HPLC analysis, while antioxidant capacity was determined by ORAC method. Furthermore, in vitro cytotoxicity of prepared extracts was assessed by antiproliferation assay on two tumour cell lines, whereas for investigation of type of cell death or cell cycle arrest a flow cytometric analysis was applied. In addition, a detection of compounds with DNA/RNA-binding affinity in extracts was investigated by UV/Vis and circular dichroism spectroscopy. Grape pomace extract in NADES showed to be the best of all extracts tested, with regard to extraction of total polyphenolic compounds (p < 0.05) and related biological activities such as antioxidant and antiproliferative activity. Prepared polyphenolic extracts in NADES could be considered as ready-to-use in food and pharmaceutical industry without demanding and expensive downstream purification steps.
... Choline. Choline was the first example of a conditional vitamin (44): only 11% of women achieve the recommended intake and the average intakes for the population are half to two-thirds of this recommendation (45); severe choline deficiency results in DNA strand breaks in rodents, alterations to epigenetic markers and histones, and affects brain development (46)(47)(48). ...
Article
It is proposed that proteins/enzymes be classified into two classes according to their essentiality for immediate survival/reproduction and their function in long-term health: that is, survival proteins versus longevity proteins. As proposed by the triage theory, a modest deficiency of one of the nutrients/cofactors triggers a built-in rationing mechanism that favors the proteins needed for immediate survival and reproduction (survival proteins) while sacrificing those needed to protect against future damage (longevity proteins). Impairment of the function of longevity proteins results in an insidious acceleration of the risk of diseases associated with aging. I also propose that nutrients required for the function of longevity proteins constitute a class of vitamins that are here named “longevity vitamins.” I suggest that many such nutrients play a dual role for both survival and longevity. The evidence for classifying taurine as a conditional vitamin, and the following 10 compounds as putative longevity vitamins, is reviewed: the fungal antioxidant ergothioneine; the bacterial metabolites pyrroloquinoline quinone (PQQ) and queuine; and the plant antioxidant carotenoids lutein, zeaxanthin, lycopene, α- and β-carotene, β-cryptoxanthin, and the marine carotenoid astaxanthin. Because nutrient deficiencies are highly prevalent in the United States (and elsewhere), appropriate supplementation and/or an improved diet could reduce much of the consequent risk of chronic disease and premature aging.
... Additionally, nutritional deficiencies cause epigenetic modifications, which potentially alter individual susceptibility to hepatotoxicity. Deficiencies of folic acids, vitamin B12, and choline induce methyl donor depletion, contributing to hypomethylation of genes in cellular metabolism and hepatocyte differentiation [98][99][100]. Folic acid deficiency is associated with more severe liver damage in ethanol-fed micropigs [101,102] while folic acid supplementation has been associated with a reduced reporting frequency of liver events across different agents with hepatotoxic potential in previous data-mining analyses [83,84]. ...
Article
Background & Aims Most patients with drug‐induced liver injury (DILI) manifest clinical symptoms while on therapy, while some patients manifest days or weeks after drug cessation (delayed onset). This challenges DILI causality assessment and diagnosis. Factors contributing to the delayed onset phenotype are currently unknown. We explored factors contributing to delayed onset of DILI by analyzing culprit drug properties, host factors and their interactions in a large patient population from the Spanish DILI Registry. Methods Clinical information from 388 patients (69 presented delayed onset) and drug properties of 43 causative drugs (45 active ingredients) were analyzed. A two‐tier regression‐based model was used to assess host/drug interactions affecting the probability of delayed onset. Results Antibacterial and antiinflammatory drugs accounted for the delayed onset cases. Drug property of <50% hepatic metabolism [Odds ratio (OR) 11.06, 95% confidence interval (95%CI): 4.4‐32.2, p=0.0003], daily dose ≥1000 mg [OR: 2.77, 95%CI: 1.3‐6.1, p=0.0063] and the absence of pre‐existing conditions in a patient [OR: 2.55, 95%CI: 1.3‐4.9, p=0.0043] were independently associated with delayed onset. The findings were consistent when externally validated using Latin‐American DILI Network cases (N=131). Likewise, drug properties of mitochondrial liability and Pauling electronegativity were associated with delayed onset, but dependent on specific host factors such as age, sex, and pre‐existing cardiac diseases. Conclusions This study demonstrated that delayed onset, a specific DILI phenotype, is explained by complex interactions among drug properties and host factors and provided mechanistic hypotheses for future studies. These findings can help improve the diagnostic capability and causality assessment. This article is protected by copyright. All rights reserved.
... Choline regulates secretion of triglyceride rich lipoprotein particles and its deficiency has been linked to lower serum TG concentration 28 . Since PCs are a major source of choline; an important epigenetic regulator in the body 29 , it is conceivable that alterations in the choline metabolism during infancy, e.g. by diet, may affect the PC levels, resulting in the decreased levels of TGs as well as PCs. In addition, the decreased levels of TGs may also suggest increased energy demand in PT1D group as compared to P1Ab 30 . ...
Article
Full-text available
Type 1 diabetes (T1D) is one of the most prevalent autoimmune diseases among children in Western countries. Earlier metabolomics studies suggest that T1D is preceded by dysregulation of lipid metabolism. Here we used a lipidomics approach to analyze molecular lipids in a prospective series of 428 plasma samples from 40 children who progressed to T1D (PT1D), 40 children who developed at least a single islet autoantibody but did not progress to T1D during the follow-up (P1Ab) and 40 matched controls (CTR). Sphingomyelins were found to be persistently downregulated in PT1D when compared to the P1Ab and CTR groups. Triacylglycerols and phosphatidylcholines were mainly downregulated in PT1D as compared to P1Ab at the age of 3 months. Our study suggests that distinct lipidomic signatures characterize children who progressed to islet autoimmunity or overt T1D, which may be helpful in the identification of at-risk children before the initiation of autoimmunity.
... Environmental factors including tobacco and alcohol use, exposure to selected environmental chemicals, obesity, and diet, have been postulated to play a significant role in the etiology of sporadic pancreatic cancer [3]. Deficiencies in dietary sources of methyl groups, including choline, methionine, vitamin B-12 and folate, have been associated with pancreatic dysfunction in rodents [4,5]. In addition, risk of development of various cancer types in humans, including pancreatic cancer, has been shown to increase with low dietary folate intake [6][7][8][9]. ...
Article
Full-text available
Background Pancreatic cancer is the third leading cause of cancer related deaths in the United States. Several dietary factors have been identified that modify pancreatic cancer risk, including low folate levels. In addition to nutrition and lifestyle determinants, folate status may be influenced by genetic factors such as single nucleotide polymorphisms (SNPs). In the present study, we investigated the association between folate levels, genetic polymorphisms in genes of the folate pathway, and pancreatic cancer. Methods Serum and red blood cell (RBC) folate levels were measured in pancreatic cancer and control subjects. Genotypes were determined utilizing Taqman probes and SNP frequencies between cases and controls were assessed using Fisher’s exact test. Logistic regression was used to estimate the odds ratio (OR) and corresponding 95% confidence intervals (CIs) to measure the association between genotypes and pancreatic cancer risk. The association between folate levels and SNP expression was calculated using one-way ANOVA. Results Mean RBC folate levels were significantly lower in pancreatic cancer cases compared to unrelated controls (508.4 ± 215.9 ng/mL vs 588.3 ± 229.2 ng/mL, respectively) whereas serum folate levels were similar. Irrespective of cancer status, several SNPs were found to be associated with altered serum folate concentrations, including the D919G SNP in methionine synthase (MTR), the L474F SNP in serine hydroxymethyl transferase 1 (SHMT1) and the V175M SNP in phosphatidyl ethanolamine methyltransferase (PEMT). Further, the V allele of the A222V SNP and the E allele of the E429A SNP in methylene tetrahydrofolate reductase (MTHFR) were associated with low RBC folate levels. Pancreatic cancer risk was found to be significantly lower for the LL allele of the L78R SNP in choline dehydrogenase (CHDH; OR = 0.29; 95% CI 0.12–0.76); however, it was not associated with altered serum or RBC folate levels.
... The present study shows that exposure to BPA causes significant, dose-dependent decrease in energy metabolism. ATPase is required for enzymatic hydrolysis of ATP, which is important for intracellular transfer of energy (Zeisel, 2012). Activity of SDH, also significantly decreased in cauda epididymis by BPA administration. ...
Article
Full-text available
Bisphenol A is widely used as a material for the production of epoxy resins and polycarbonate plastics. It contaminates various food stuffs by getting leached out from their container lining. Limited information is available on its effects on male reproductive system. The aim of the present study was to evaluate the extent to which bisphenol A can affect the reproductive system by measuring biochemical and histological changes in epididymis. Inbred Swiss strain male albino mice were orally administered with 80, 120 and 240 mg/kg body weight/day of BPA for 45 Days. After completion of treatment animals were sacrificed; cauda epididymis was isolated weighted, used for biochemical and histopathological and studies. The results revealed that; BPA for 45 days caused significant (p<0.05) and dose-dependent reduction in epididymis weight. There was significant (p<0.05) increase in lipid peroxidation and the acid phosphatase activity. There was dose dependent reduction in protein, Sialic acid contents as well as the activity of enzymatic antioxidants and mitochondrial enzymes compared to vehicle treated group. The effect was dose-dependent. Histopathological alteration was observed. This study concludes that BPA causes toxicity in epididymis of mice by generating free radicals which may be possible reason for reduction in sperm parameters.
... Dietary methyl (C1) donors, such as folate, methionine, and choline, are known players important for methylation of DNA in spermatogenesis [93] and variations in the availability of those metabolites change the DNA methylation component of the sperm epigenome. How deficient or excessive uptake of these methyl donor changes body-wide and importantly germ cell-specific methylation of histones is not understood [94][95][96][97][98]. Targeted research needs to address the question to what extent dietary C1 donors affect the sperm chromatin-borne epigenome, specifically the methylation of histones, in addition to the sperm DNA methylome [94]. ...
Article
Sperm chromatin not only has a unique structure to condense and protect the paternal DNA in transit, but also provides epigenetic information that supports embryonic development. Most of the unique sperm nuclear architecture is formed during the sweeping postmeiotic chromatin remodeling events in spermiogenesis, where the majority of nucleosomes are removed and replaced by protamines. The remaining histones and other chromatin proteins are located in structurally and transcriptionally relevant positions in the genome and carry diverse posttranslational modifications relevant to the control of embryonic gene expression. How such postmeiotic chromatin-based programming of sperm epigenetic information proceeds, and how susceptible the process is to modulation by exogenous factors are key questions for understanding the inheritance of acquired epigenetic marks through the male germ line. We propose that transient DNA strand breaks mediated by topoisomerase 2 beta and the subsequent activation of DNA damage response pathways result in defined posttranslational modifications of histones in spermiogenesis. These pathways, likely along with others, may contribute to chromatin remodeling in elongating spermatids, influence chromatin-based intergenerational inheritance of epigenetic information, and may be defective in pathologies of abnormal male gametogenesis and infertility.
... [6][7][8][9] At the molecular level, choline deficiency causes DNA strand breaks, 10 which is the consequence of impaired DNA methylation due to the lack of methyl groups, altered mitochondrial membrane composition and hence leakage of reactive oxygen species, and diminished thymidylate synthesis due to the lack of folate. 11 The choline transporter family of SLC44A proteins As a charged molecule, choline cannot freely cross the membrane lipid bilayer and depends on protein transporters to enter the cell. Three different choline transport systems have been identified (Figure 1). ...
Article
Full-text available
This review provides a summary of recent discoveries in choline transport and the proteins mediating it with a specific focus on the choline transporter-like proteins (CTL)/solute carriers 44 A (SLC44A) and their role in phospholipid metabolism. Since its initial cloning, particularly, the CTL1/SLC44A1 transporter has been investigated further and its ubiquitous expression characterized in various cells and tissues of mouse, rat, and human origin. We describe the role of this choline transporter both in the plasma membrane and in the mitochondria and summarize novel aspects of choline transport regulation in the muscle, nervous system, and cancer. Impact statement This review will provide a summary of recent advances in choline transport research and highlight important novel areas of focus in the field.
... The amount of dietary choline to prevent organ damage or to maintain normal organ function varies between people (Section 5.1.2). In addition, there is some evidence that the susceptibility to develop fatty liver with choline deficiency is influenced by the gastrointestinal microbiome (Spencer et al., 2011) (Appendix D). Zeisel (2012) reviewed the potential effects of choline deficiency on gene expression via epigenetic marks and DNA integrity that could result in increased mutation rates and thereby increased risks of certain cancers. An influence on the risk of breast cancer of single nucleotide polymorphisms (SNPs) of several genes involved in choline metabolism and enhancing the requirement for dietary choline has been observed in large epidemiological studies (Xu et al., 2008(Xu et al., , 2009) (Appendix C and Section 2.5). ...
Article
Full-text available
Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) derives Dietary Reference Values (DRVs) for choline. In this Opinion, the Panel considers dietary choline including choline compounds (e.g. glycerophosphocholine, phosphocholine, phosphatidylcholine, sphingomyelin). The Panel considers that none of the biomarkers of choline intake or status is suitable to derive DRVs for choline. The Panel considers that Average Requirements and Population Reference Intakes for choline cannot be derived for adults, infants and children, and therefore defines Adequate Intakes (AIs). For all adults, the Panel sets an AI at 400 mg/day based on the average observed choline intake in healthy populations in the European Union and in consideration of the amounts of choline needed to replete about 70% of depleted subjects who showed signs of organ dysfunction in a depletion/repletion study. For all infants aged 7–11 months, the Panel proposes an AI of 160 mg/day, based on upwards extrapolation from the estimated choline intake of exclusively breast-fed infants from birth to 6 months. For all children aged 1–17 years, the Panel proposes AIs, based on downwards extrapolation from the adult AI, applying growth factors. These AIs range from 140 mg/day (1–3 years) to 400 mg/day (15–17 years). For pregnant women, the Panel derives an AI of 480 mg/day, calculated by extrapolation from the AI for non-pregnant women and the mean gestational increase in body weight. For lactating women, the amount of choline secreted per day in human milk during the first 6 months of exclusive breastfeeding (120 mg/day) is added to the AI for non-lactating women and an AI of 520 mg/day is set.
... CDP-choline, an intermediate in the de novo production of phosphatidylcholine from choline (Kennedy and Weiss, 1956), was also detected at lower levels in the CC + mice ( Figure S1C). During choline deficiency, hepatocytes overproduce reactive oxygen species (ROS) due to abnormal mitochondrial function and inhibition of complex I, which can lead to the signaling of apoptosis (Zeisel, 2012). Mitochondrial ROS production stimulates the transsulfuration pathway and early release of internal glutathione stores (Bhandary et al., 2012). ...
Article
Choline is an essential nutrient and methyl donor required for epigenetic regulation. Here, we assessed the impact of gut microbial choline metabolism on bacterial fitness and host biology by engineering a microbial community that lacks a single choline-utilizing enzyme. Our results indicate that choline-utilizing bacteria compete with the host for this nutrient, significantly impacting plasma and hepatic levels of methyl-donor metabolites and recapitulating biochemical signatures of choline deficiency. Mice harboring high levels of choline-consuming bacteria showed increased susceptibility to metabolic disease in the context of a high-fat diet. Furthermore, bacterially induced reduction of methyl-donor availability influenced global DNA methylation patterns in both adult mice and their offspring and engendered behavioral alterations. Our results reveal an underappreciated effect of bacterial choline metabolism on host metabolism, epigenetics, and behavior. This work suggests that interpersonal differences in microbial metabolism should be considered when determining optimal nutrient intake requirements.
... 136 Inadequate intake of methyl donors, including choline and folate, alters DNA methylation and histone modifications. 137,138 Our group found that 24-week-old tx-j mice have hypomethylated DNA compared with wild-type mice and that DNA methylation in tx-j mice is restored to wild-type levels with 4 weeks of betaine supplementation. 104 These results have not been confirmed in humans, due to the lack of studies on DNA methylation status in patients with WD. ...
Article
Full-text available
Environmental factors, including diet, exercise, stress, and toxins, profoundly impact disease phenotypes. This review examines how Wilson disease (WD), an autosomal recessive genetic disorder, is influenced by genetic and environmental inputs. WD is caused by mutations in the copper-transporter gene ATP7B, leading to the accumulation of copper in the liver and brain, resulting in hepatic, neurological, and psychiatric symptoms. These symptoms range in severity and can first appear anytime between early childhood and old age. Over 300 disease-causing mutations in ATP7B have been identified, but attempts to link genotype to the phenotypic presentation have yielded little insight, prompting investigators to identify alternative mechanisms, such as epigenetics, to explain the highly varied clinical presentation. Further, WD is accompanied by structural and functional abnormalities in mitochondria, potentially altering the production of metabolites that are required for epigenetic regulation of gene expression. Notably, environmental exposure affects the regulation of gene expression and mitochondrial function. We present the “multi-hit” hypothesis of WD progression, which posits that the initial hit is an environmental factor that affects fetal gene expression and epigenetic mechanisms and subsequent “hits” are environmental exposures that occur in the offspring after birth. These environmental hits and subsequent changes in epigenetic regulation may impact copper accumulation and ultimately WD phenotype. Lifestyle changes, including diet, increased physical activity, stress reduction, and toxin avoidance, might influence the presentation and course of WD, and therefore may serve as potential adjunctive or replacement therapies.
... Additionally, nutritional deficiencies cause epigenetic modifications, which potentially alter individual susceptibility to hepatotoxicity. Deficiencies of folic acids, vitamin B12, and choline induce methyl donor depletion, contributing to hypomethylation of genes in cellular metabolism and hepatocyte differentiation [98][99][100]. Folic acid deficiency is associated with more severe liver damage in ethanol-fed micropigs [101,102] while folic acid supplementation has been associated with a reduced reporting frequency of liver events across different agents with hepatotoxic potential in previous data-mining analyses [83,84]. ...
... Additionally, nutritional deficiencies cause epigenetic modifications, which potentially alter individual susceptibility to hepatotoxicity. Deficiencies of folic acids, vitamin B12, and choline induce methyl donor depletion, contributing to hypomethylation of genes in cellular metabolism and hepatocyte differentiation [98][99][100]. Folic acid deficiency is associated with more severe liver damage in ethanol-fed micropigs [101,102] while folic acid supplementation has been associated with a reduced reporting frequency of liver events across different agents with hepatotoxic potential in previous data-mining analyses [83,84]. ...
... Recently, dietary nutritional supplements were found to be an efficient method for improving organ antioxidant capacity. Choline is an essential vitamin for humans and other animals [3]. Our previous study showed that choline deficiency induced growth retardation and decreased growth and development of hepatopancreas and intestine in juvenile Jian carp (Cyprinus curpio var. ...
Article
Full-text available
The liver and intestine are susceptible to the oxidative damage which could result in several diseases. Choline deficiency induced oxidative damage in rat liver cells. Thus, this study aimed to investigate the potential molecular mechanisms responsible for choline deficiency-induced oxidative damage. Juvenile Jian carp were fed diets differing in choline content [165 (deficient group), 310, 607, 896, 1167 and 1820 mg/kg diet] respectively for 65 days. Oxidative damage, antioxidant enzyme activities and related gene expressions in the hepatopancreas and intestine were measured. Choline deficiency decreased choline and phosphatidylcholine contents, and induced oxidative damage in both organs, as evidenced by increased levels of oxidative-stress markers (malondialdehyde, protein carbonyl and 8-hydroxydeoxyguanosine), coupled with decreased activities of antioxidant enzymes [Copper-zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD), glutathione peroxidase (GPx) and glutathione-S-transferase (GST)]. However, choline deficiency increased glutathione contents in the hepatopancreas and intestine. Furthermore, dietary choline deficiency downregulated mRNA levels of MnSOD, GPx1b, GST-rho, mGST3 and Kelch-like ECH associating protein 1 (Keap1b) in the hepatopancreas, MnSOD, GPx1b, GPx4a, GPx4b, GST-rho, GST-theta, GST-mu, GST-alpha, GST-pi and GST-kappa in the intestine, as well as intestinal Nrf2 protein levels. In contrast, choline deficiency upregulated the mRNA levels of GPx4a, GPx4b, mGST1, mGST2, GST-theta, GST-mu, Keap1a and PKC in the hepatopancreas, mGST3, nuclear factor erythoid 2-related factor 2 (Nrf2) and Keap1a in the intestine, as well as hepatopancreatic Nrf2 protein levels. This study provides new evidence that choline deficiency-induced oxidative damage is associated with changes in the transcription of antioxidant enzyme and Nrf2/Keap1 signaling molecules in the hepatopancreas and intestine. Additionally, this study firstly indicated that choline deficiency induced varied change patterns of different GPx and GST isoforms. Meanwhile, the changes of some GPx and GST isoforms caused by choline deficiency in the intestine were contrary to those in the hepatopancreas.
... Through this process, one-carbon metabolism affects genomic stability and expression and intervenes nucleotide synthesis.Thus, a number of animals in vivo and, to a lesser extent, human studies have investigated the role of dietary choline and/or betaine and their impact on global and candidate gene DNA methylation. As, choline-deficient diet lessens hepatic folate levels in animals [42]. Parallel, a folate deficient diet lowered hepatic choline levels in animals [43]. ...
... These results provide evidence that NCLX is a key 'crossroad' factor in the control of protein and amino acid synthesis and methylation. Choline modulates epigenetic marking of genes, and choline deficiency is correlated with the silencing of several tumor suppressor genes responsible for DNA repair (hMLH1) and cell cycle regulation (p15 and p16) [45]. ...
Article
Full-text available
Background and aims Recent evidences highlight a role of the mitochondria calcium homeostasis in the development of colorectal cancer (CRC). To overcome treatment resistance, we aimed to evaluate the role of the mitochondrial sodium-calcium–lithium exchanger (NCLX) and its targeting in CRC. We also identified curcumin as a new inhibitor of NCLX. Methods We examined whether curcumin and pharmacological compounds induced the inhibition of NCLX-mediated mitochondrial calcium (mtCa²⁺) extrusion, the role of redox metabolism in this process. We evaluated their anti-tumorigenic activity in vitro and in a xenograft mouse model. We analyzed NCLX expression and associations with survival in The Cancer Genome Atlas (TCGA) dataset and in tissue microarrays from 381 patients with microsatellite instability (MSI)-driven CRC. Results In vitro, curcumin exerted strong anti-tumoral activity through its action on NCLX with mtCa²⁺ and reactive oxygen species overload associated with a mitochondrial membrane depolarization, leading to reduced ATP production and apoptosis. NCLX inhibition with pharmacological and molecular approaches reproduced the effects of curcumin. NCLX inhibitors decreased CRC tumor growth in vivo. Both transcriptomic analysis of TCGA dataset and immunohistochemical analysis of tissue microarrays demonstrated that higher NCLX expression was associated with MSI status, and for the first time, NCLX expression was significantly associated with recurrence-free survival. Conclusions Our findings highlight a novel anti-tumoral mechanism of curcumin through its action on NCLX and mitochondria calcium overload that could benefit for therapeutic schedule of patients with MSI CRC.
... In the LD group of our study, the concentration of choline was markedly increased. Choline is widely regarded as an essential vitamin to regulate amino acid metabolism [85][86][87], particularly when L-methionine levels is not sufficient around parturition [88]. In pigs with intrauterine growth restriction, dietary supplementation with choline was reported to enhance the antioxidant capacity [89]. ...
Article
Full-text available
Background In modern animal husbandry, breeders pay increasing attention to improving sow nutrition during pregnancy and lactation to favor the health of neonates. Sow milk is a main food source for piglets during their first three weeks of life, which is not only a rich repository of essential nutrients and a broad range of bioactive compounds, but also an indispensable source of commensal bacteria. Maternal milk microorganisms are important sources of commensal bacteria for the neonatal gut. Bacteria from maternal milk may confer a health benefit on the host. Methods Sow milk bacteria were isolated using culturomics followed by identification using 16S rRNA gene sequencing. To screen isolates for potential probiotic activity, the functional evaluation was conducted to assess their antagonistic activity against pathogens in vitro and evaluate their resistance against oxidative stress in damaged Drosophila induced by paraquat. In a piglet feeding trial, a total of 54 newborn suckling piglets were chosen from nine sows and randomly assigned to three treatments with different concentrations of a candidate strain. Multiple approaches were carried out to verify its antioxidant function including western blotting, enzyme activity analysis, metabolomics and 16S rRNA gene amplicon sequencing. Results The 1240 isolates were screened out from the sow milk microbiota and grouped into 271 bacterial taxa based on a nonredundant set of 16S rRNA gene sequencing. Among 80 Pediococcus isolates, a new Pediococcus pentosaceus strain (SMM914) showed the best performance in inhibition ability against swine pathogens and in a Drosophila model challenged by paraquat. Pretreatment of piglets with SMM914 induced the Nrf2-Keap1 antioxidant signaling pathway and greatly affected the pathways of amino acid metabolism and lipid metabolism in plasma. In the colon, the relative abundance of Lactobacillus was significantly increased in the high dose SMM914 group compared with the control group. Conclusion P. pentosaceus SMM914 is a promising probiotic conferring antioxidant capacity by activating the Nrf2-Keap1 antioxidant signaling pathway in piglets. Our study provided useful resources for better understanding the relationships between the maternal microbiota and offspring. EfLm9u1Sf9S1S84o-T2kafVideo Abstract
... Elevations in markers of DNA damage, as well as alterations in lymphocyte gene expression, are also commonly observed during the deficiency state (da Costa et al. 2006;Niculescu et al. 2007;Zeisel 2012). DNA methylation can strongly influence gene expression; alterations in DNA methylation have been linked to diseases such as cancer and syndromes involving chromosomal instabilities (Egger et al. 2004). ...
Article
Choline is an essential nutrient for proper liver, muscle, and brain functions as well as for lipid metabolism and cellular membrane composition and repair. Humans can produce small amounts of choline via the hepatic phosphatidylethanolamine N-methyltransferase pathway; however, most individuals must consume this vitamin through the diet to prevent deficiency. An individual’s dietary requirement for choline is dependent on common genetic variants in genes required for choline, folate, and one-carbon metabolism. Both the American Academy of Pediatrics and American Medical Association have recently reinforced the importance of maternal choline intake during pregnancy and lactation and recognize that failure to provide choline and other key essential nutrients during the first 1,000 days postconception may result in lifelong deficits in brain function despite subsequent nutrient repletion. Given that dietary intake for the majority of the US population, including subpopulations such as pregnant women, women of childbearing age, and vegetarians, falls well below the current adequate intake, there is a need to develop better policies and improve consumer education around the importance of this essential nutrient for human health. This comprehensive expert review summarizes the current scientific evidence on choline and health in relation to interests of obstetricians and gynecologists.
... Cysteine and methionine metabolism is overlapped with choline metabolism tightly because choline can serve as the substrate for L-methionine synthesis. Choline is an essential vitamin for humans and other mammals to regulate amino acid metabolism [52], particularly when L-methionine levels are not su cient around parturition [53]. It has been established that choline de ciency induces the generation of ROS [54] and oxidative damage in rats [55], ruminants [56] and shes [57]. ...
Preprint
Full-text available
Background: In modern animal husbandry, the relationship between sow and piglets is closely linked as breeders pay more attention to improving sow nutrition during pregnancy and lactation to favor the growing of neonates. Sow milk is the main food for piglets during their first three weeks of life, which is not only a rich repository of essential nutrients and a broad range of bioactive compounds, but also an indispensable source of commensal bacteria. Maternal milk microorganisms are important sources of commensal bacteria for neonatal gut. Bacteria from hosts’ maternal milk may serve as an additive to confer a health benefit on the composition of the indigenous microbiota of piglets. Methods: We first obtained isolates from the sow milk microbiota by the culturomics methods of continuous culture and interval sampling. Then, identified and grouped them based on a nonredundant set of 16S rDNA gene sequences. After assessing their antimicrobial activity against enteropathogens in vitro, we selected several strains to further conduct assay in Drosophila to evaluate their resistance against oxidative injury. We finally screened out Pediococcus pentosaceus (P. pentosaceus) SMM914 as candidate strain to verify its antioxidant effect in weaned piglets and study its probiotic function by 16S rDNA sequencing, metabolomics, western blotting and enzyme activity analysis. Results: The 1240 isolates were screened out from the sow milk microbiota and grouped into 271 bacterial taxa. We evaluated 80 Pediococcus isolates about their inhibition ability against enteropathogens in vitro and then chose top 10 isolates to further test them in Drosophila. In 80 Pediococcus isolates, P. pentosaceus SMM914 showed best performance by inhibition ability against enteropathogens in vitro andparaquat challenge in Drosophila model. Pretreatment of piglets with SMM914 induces the Nrf2/Keap1 antioxidant signaling pathway and altered the pathways of amino acid metabolism and lipid metabolism in plasma. In colon, Lactobacillus was significantly increased in the high dose of SMM914 group compared with the control group. Conclusion: Our study provided useful resources for deeply understanding the relationships between the maternal microbiota and the offspring and supported the theory of Sow and Piglet Integration.
... These results showed that NCLX is a key 'crossroad' factor in the control of protein and amino acid synthesis and methylation. Choline modulates epigenetic marking of genes, and choline deficiency is correlated with the silencing of several tumor suppressor genes responsible for DNA repair (hMLH1) and cell cycle regulation (p15 and p16) (40). In the future, we aim to distinguish unique metabolic profiles or easy-to-implement signatures that would be useful as minimally invasive biomarkers of NCLX inhibition in a clinical context. ...
Preprint
Colorectal cancer (CRC) is associated with high mortality worldwide and new targets are needed to overcome treatment resistance. Recent evidences highlight a role of the mitochondria calcium homeostasis in the development of CRC. In this context, we aimed to evaluate the role of the mitochondrial sodium-calcium-lithium exchanger (NCLX) and its targeting in CRC. We also identified curcumin as a new potential inhibitor of NCLX. In vitro, curcumin exerted strong anti-tumoral activity through its action on NCLX with mtCa2+ and reactive oxygen species overload associated with a mitochondrial membrane depolarization, leading to reduced ATP production and apoptosis through mitochondrial permeability transition pore opening concomitant with G2/M cell cycle arrest. NCLX inhibition with either CGP37157 (a benzodiazepine derivative), small interfering RNA-mediated knock-down or knockout approaches reproduced the effects of curcumin. Altered mitochondrial respiration, cellular aerobic glycolysis and endoplasmic reticulum–mitochondria membrane perturbations participated in these mechanisms. In a xenograft mouse model, NCLX inhibitors decreased CRC tumor growth. Both transcriptomic analysis of The Cancer Genome Atlas dataset and immunohistochemical analysis of tissue microarrays from 381 patients with microsatellite instability (MSI)-driven CRC demonstrated that higher NCLX expression was associated with MSI status and for the first time NCLX expression was significantly associated with recurrence-free survival in MSI CRC patients. Our findings provide strong evidence that blocking NCLX inhibits CRC in vitro and in vivo. We highlight a novel anti-tumoral mechanism of curcumin through its action on NCLX and mitochondria calcium overload that could benefit for therapeutic treatment of patients with MSI CRC.
... This dual role is thought to be attributable to folate's function of providing methyl-groups for the biosynthesis of nucleotides (purines and thymidylate) required for DNA synthesis in rapidly proliferating tissues [37,38]. Given their high proliferation rate, cancer cells might also have a large demand for choline, which is a precursor for the synthesis of cell membrane phospholipids [39,40], and methionine for protein synthesis [41]; both mechanisms are essential for cell development and functioning. Therefore, the amount and timing of intake could be crucial in cancer development. ...
Article
Full-text available
(1) Background: Methyl-group donors (MGDs), including folate, choline, betaine, and methionine, may influence breast cancer (BC) risk through their role in one-carbon metabolism; (2) Methods: We studied the relationship between dietary intakes of MGDs and BC risk, adopting data from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort; (3) Results: 318,686 pre- and postmenopausal women were followed between enrolment in 1992–2000 and December 2013–December 2015. Dietary MGD intakes were estimated at baseline through food-frequency questionnaires. Multivariable Cox proportional hazards regression models were used to quantify the association between dietary intake of MGDs, measured both as a calculated score based on their sum and individually, and BC risk. Subgroup analyses were performed by hormone receptor status, menopausal status, and level of alcohol intake. During a mean follow-up time of 14.1 years, 13,320 women with malignant BC were identified. No associations were found between dietary intakes of the MGD score or individual MGDs and BC risk. However, a potential U-shaped relationship was observed between dietary folate intake and overall BC risk, suggesting an inverse association for intakes up to 350 µg/day compared to a reference intake of 205 µg/day. No statistically significant differences in the associations were observed by hormone receptor status, menopausal status, or level of alcohol intake; (4) Conclusions: There was no strong evidence for an association between MGDs involved in one-carbon metabolism and BC risk. However, a potential U-shaped trend was suggested for dietary folate intake and BC risk. Further research is needed to clarify this association.
... Defective DNA methylation and impaired DNA repair are the reasons for development of deficiency related complications. [42]Betaine intake can also contribute to reduction in homocysteine level. [43] Mutation occurs at nucleotide 742 in exon 6 of the gene, resulting in replacement of glutamine with arginine in structure of the enzyme. ...
... [18][19][20] Choline is an essential nutrient 21 utilized for the synthesis of the neurotransmitter acetylcholine (cholinergic activity) and membrane lipids, such as phosphatidylcholine and sphingomyelin that are necessary for cellular integrity and maintenance of efficient mitochondrial oxidative phosphorylation. Choline is also needed for one-carbon (methyl-group) metabolism required for the epigenetic modulation of gene expression/genomic stability and several other methyl-group transfer reactions 22 and is an intracellular messenger (agonist), signalling through brain abundant sigma-1 receptors that are involved in cholinergic transmissions. 23 In the context of cancer-cachexia, cholinergic signalling is involved with modulating inflammation and appetite in the basal forebrain and hypothalamus. ...
Article
Full-text available
Background: Cachexia is a major cause of morbidity in pancreatic ductal adenocarcinoma (PDAC) patients. Our purpose was to understand the impact of PDAC-induced cachexia on brain metabolism in PDAC xenograft studies, to gain new insights into the causes of cachexia-induced morbidity. Changes in mouse and human plasma metabolites were characterized to identify underlying causes of brain metabolic changes. Methods: We quantified metabolites, detected with high-resolution 1 H magnetic resonance spectroscopy, in the brain and plasma of normal mice (n = 10) and mice bearing cachexia (n = 10) or non-cachexia (n = 9) inducing PDAC xenografts as well as in human plasma obtained from normal individuals (n = 24) and from individuals with benign pancreatic disease (n = 20) and PDAC (n = 20). Statistical significance was defined as a P value ≤0.05. Results: The brain metabolic signature of cachexia-inducing PDAC was characterized by a significant depletion of choline of -27% and -21% as well as increases of glutamine of 13% and 9% and formate of 21% and 14%, relative to normal controls and non-cachectic tumour-bearing mice, respectively. Good to moderate correlations with percent weight change were found for choline (r = 0.70), glutamine (r = -0.58), and formate (r = -0.43). Significant choline depletion of -38% and -30%, relative to normal controls and non-cachectic tumour-bearing mice, respectively, detected in the plasma of cachectic mice likely contributed to decreased brain choline in cachectic mice. Similarly, relative to normal controls and patients with benign disease, choline levels in human plasma samples of PDAC patients were significantly lower by -12% and -20% respectively. A comparison of plasma metabolites from PDAC patients with and without weight loss identified significant changes in glutamine metabolism. Conclusions: Disturbances in metabolites of the choline/cholinergic and glutamine/glutamate/glutamatergic neurotransmitter pathways may contribute to morbidity. Metabolic normalization may provide strategies to reduce morbidity. The human plasma metabolite changes observed may lead to the development of companion diagnostic markers to detect PDAC and PDAC-induced cachexia.
... It is also a precursor of the neurotransmitter acetylcholine, and following oxidation to betaine, choline functions as a methyl group donor in pathways that produce S-adenosylmethionine (Li and Vance 2008). As a methyl donor, choline can influence DNA and histone methylation (Zeisel 2012). Choline deficiency has been linked to neurological impairment (Paoletti et al. 2011) and is recognized as a potential new cardiac marker in previous study (Wang et al. 2014). ...
Article
Full-text available
Long-term exposure to particular matter (PM), especially fine PM (< 2.5 μm in the aerodynamic diameter, PM2.5), is associated with increased risk of cardiovascular disorders. This study aimed to evaluate the association between long-term exposure to PM2.5/PM10 and the metabolic change in the plasma. Specifically, using metabolomics, we sought to identify the biomarkers for the vulnerable subgroup to PM2.5 exposure. A total of 78 college student volunteers were recruited into this prospective cohort study. All participants received 8 rounds of physical examinations at twice quarterly. Air purifiers were placed in 40 of 78 participants’ dormitories for 14 days. Before and after intervention, physical examinations were performed and the peripheral blood was collected. Plasma metabolomics was determined by ultra-performance liquid chromatography-mass spectrometry. During the follow-up, the average concentrations of PM2.5 and PM10 were 53 μg/m³ and 93 μg/m³, respectively. Totally, 42 and 120 differential metabolic features were detected for PM10 and PM2.5 exposure, respectively. In total, 25 differential metabolites were identified for PM2.5 exposure, most of which were phospholipids. No distinctive metabolites were found for PM10 exposure. A total of 6 differential metabolites (lysoPC (P-20:0), lysoPC (P-18:1(9z)), lysoPC (20:1), lysoPC (O-16:0), choline, and found 1,3-diphenylprop-2-en-1-one) were characterized and confirmed for sensitive individuals. Importantly, we found LysoPC (P-20:0) and LysoPC (P-18:1(9z)) changed significantly before and after air purifier intervention. Our results indicated that the phospholipid catabolism was involved in long-term PM2.5 exposure. LysoPC (P-20:0) and LysoPC (P-18:1(9z)) may be the biomarkers of PM2.5 exposure.
... To ensure the smooth functioning of DNA damage response systems, it is also important to maintain a balance of macronutrients (in particular, proteins and amino acids) in food and its caloric content [885]. Despite the fact that a moderate decrease in methionine and choline levels in the diet has a positive effect on lifespan and health, their critical deficiency increases the generation of DNA damages, causes significant epigenomic changes leading to organ and tissue dysfunction and carcinogenesis [980,1097,1098]. On the other hand, excessive calorie intake and being overweight are also associated with a high increase in DNA damage and inhibition of DNA repair systems, which indicates the important role of proper macronutrient intake in maintaining genome integrity [885,938,1099]. ...
Article
Throughout life, organisms are exposed to various exogenous and endogenous factors that cause DNA damages and somatic mutations provoking genomic instability. At a young age, compensatory mechanisms of genome protection are activated to prevent phenotypic and functional changes. However, the increasing stress and age-related deterioration in the functioning of these mechanisms result in damage accumulation, overcoming the functional threshold. This leads to aging and the development of age-related diseases. There are several ways to counteract these changes: 1) prevention of DNA damage through stimulation of antioxidant and detoxification systems, as well as transition metal chelation; 2) regulation of DNA methylation, chromatin structure, non-coding RNA activity and prevention of nuclear architecture alterations; 3) improving DNA damage response and repair; 4) selective removal of damaged non-functional and senescent cells. In the article, we have reviewed data about the effects of various trace elements, vitamins, polyphenols, terpenes, and other phytochemicals, as well as a number of synthetic pharmacological substances in these ways. Most of the compounds demonstrate the geroprotective potential and increase the lifespan in model organisms. However, their genome-protecting effects are non-selective and often are conditioned by hormesis. Consequently, the development of selective drugs targeting genome protection is an advanced direction.
... Decline of estrogen levels after menopause or the presence of genetic polymorphisms (SNPs) in the hepatic PEMT gene predisposes women to a depletion in choline as they age and increase their susceptibility to diseases [37]. Depletion of choline during adulthood has also been linked to organ or cellular dysfunction such as nonalcoholic fatty liver, liver damage, muscle damage, lymphocyte apoptosis and DNA damage [38][39][40]. ...
Article
Full-text available
Recent evidence suggests that physical and mental health are influenced by an intricate interaction between genes and environment. Environmental factors have been shown to modulate neuronal gene expression and function by epigenetic mechanisms. Exposure to these factors including nutrients during sensitive periods of life could program brain development and have long-lasting effects on mental health. Studies have shown that early nutritional intervention that includes methyl-donors improves cognitive functions throughout life. Choline is a micronutrient and a methyl donor that is required for normal brain growth and development. It plays a pivotal role in maintaining structural and functional integrity of cellular membranes. It also regulates cholinergic signaling in the brain via the synthesis of acetylcholine. Via its metabolites, it participates in pathways that regulate methylation of genes related to memory and cognitive functions at different stages of development. Choline-related functions have been dysregulated in some neurodegenerative diseases suggesting choline role in influencing mental health across the lifespan.
... Sphingomyelins are one of the major choline-containing phospholipids in circulation. Choline is a precursor for the biosynthesis of PCs and SMs [11,12], which are essential constituents of cellular membranes [13]. It is, however, challenging to identify the sources of the observed lipid changes in cord blood. ...
Article
Full-text available
Previous studies suggest that children who progress to type 1 diabetes (T1D) later in life already have an altered serum lipid molecular profile at birth. Here, we compared cord blood lipidome across the three study groups: children who progressed to T1D (PT1D; n = 30), children who developed at least one islet autoantibody but did not progress to T1D during the follow-up (P1Ab; n = 33), and their age-matched controls (CTR; n = 38). We found that phospholipids, specifically sphingomyelins, were lower in T1D progressors when compared to P1Ab and the CTR. Cholesterol esters remained higher in PT1D when compared to other groups. A signature comprising five lipids was predictive of the risk of progression to T1D, with an area under the receiver operating characteristic curve (AUROC) of 0.83. Our findings provide further evidence that the lipidomic profiles of newborn infants who progress to T1D later in life are different from lipidomic profiles in P1Ab and CTR.
Article
Mounting evidence suggests that environmental stress experienced in utero (for example, maternal nutritional deficits) establishes a predisposition in the newborn to the development of chronic diseases later in life. This concept is often referred to as the "fetal origins hypothesis" or "developmental origins of health and disease". Since its first proposal, epigenetics has emerged as an underlying mechanism explaining how environmental cues become gestationally "encoded". Many of the enzymes that impart and maintain epigenetic modifications are highly sensitive to nutrient availability, which can be influenced by the metabolic activities of the intestinal microbiota. Therefore, the maternal microbiome has the potential to influence epigenetics in utero and modulate offspring's long-term health trajectories. Here we summarize the current understanding of the interactions that occur between the maternal gut microbiome and the essential nutrient choline, that is not only required for fetal development and epigenetic regulation but is also a growth substrate for some microbes. Bacteria able to metabolize choline benefit from the presence of this nutrient and compete with the host for its access, which under extreme conditions may elicit signatures of choline deficiency. Another consequence of bacterial choline metabolism is the accumulation of the pro-inflammatory, pro-thrombotic metabolite trimethylamine-N-oxide (TMAO). Finally, we discuss how these different facets of microbial choline metabolism may influence infant development and health trajectories via epigenetic mechanisms and more broadly place a call to action to better understand how maternal microbial metabolism can shape their offspring's propensity to chronic disease development later in life.
Article
It was hypothesized that choline supplementation in insulin resistant (IR) CTP:phosphoethanolamine cytidylyltransferase deficient (Pcyt2(+/-)) mice would ameliorate muscle function by remodeling glucose and fatty acid (FA) metabolism. Pcyt2(+/-) mice either received no treatment or were allowed access to 2 mg/mL choline in drinking water for 4 weeks. Skeletal muscle was harvested from choline treated and untreated mice. Lipid analysis and metabolic gene expression and signaling pathways were compared between untreated Pcyt2(+/-) mice, treated Pcyt2(+/-) mice, and Pcyt2(+/+) mice. The major positive effect of choline supplementation on IR muscle was the reduction of glucose utilization for FA and triglyceride (TAG) synthesis and increased muscle glucose storage as glycogen. Choline reduced the expression of genes for FA and TAG formation (Scd1, Fas, Srebp1c, Dgat1/2), upregulated the genes for FA oxidation (Cpt1, Pparα, Pgc1α), and had minor effects on phospholipid and lipolysis genes. Pcyt2(+/-) muscle had reduced insulin signaling (IRS1), autophagy (LC3), and choline transport (CTL1) proteins that were restored by choline treatment. Additionally, choline activated AMPK and Akt while inhibiting mTORC1 phosphorylation. These data established that choline supplementation could restore muscle glucose metabolism by reducing lipogenesis and improving mitochondrial and intracellular signaling for protein and energy metabolism in insulin resistant Pcyt2 deficient mice.
Article
Full-text available
To become resistant, cancer cells need to activate and maintain molecular defense mechanisms that depend on an energy trade-off between resistance and essential functions. Metabolic reprogramming has been shown to fuel cell growth and contribute to cancer drug resistance. Recently, changes in lipid metabolism have emerged as an important driver of resistance to anticancer agents. In this review, we highlight the role of choline metabolism with a focus on the phosphatidylcholine cycle in the regulation of resistance to therapy. We analyze the contribution of phosphatidylcholine and its metabolites to intracellular processes of cancer cells, both as the major cell membrane constituents and source of energy. We further extended our discussion about the role of phosphatidylcholine-derived lipid mediators in cellular communication between cancer and immune cells within the tumor microenvironment, as well as their pivotal role in the immune regulation of therapeutic failure. Changes in phosphatidylcholine metabolism are part of an adaptive program activated in response to stress conditions that contribute to cancer therapy resistance and open therapeutic opportunities for treating drug-resistant cancers.
Article
In recent years, numerous studies have confirmed the vital role and therapeutic potential of quaternary ammonium compounds and endogenous formaldehyde in the prevention and treatment of diseases. These compounds participate in the transmethylation processes and play a role in the metabolism and in the regulation of cellular processes. The present research indicates that sour cherry fruit contains large quantities of quaternary ammonium compounds in the early developmental phase (burgeoning). The quantity of methyl-donor compounds (choline, carnitine) and easily mobilizable methyl groups were measured in various fruit parts (stalk, fruit flesh, seed kernel) of five sour cherry cultivars using OPLC technology, and the cultivar dependence of the detected compounds was examined. The results of comparative examinations established the presence of choline in the stalk and seed and of a significant amount of carnitine in the fruit flesh. The clear, significant differences between the genotypes will facilitate the selection of cultivars containing the largest proportion of components beneficial for human health.
Chapter
Choline is considered an essential nutrient and can be found in the diet in both lipid- and water-soluble form natively in foods, added during food processing (e.g., lecithin), or in dietary supplements. Choline requirements can vary considerably dependent upon life-stage, nutrient-nutrient interactions, as well as variation in capacity for endogenous formation. Choline is required to support three primary metabolic processes: (1) acetylcholine synthesis; (2) oxidation to betaine, both an osmolyte as well as a major methyl donor for generation of the universal methyl donor, S-adenosylmethionine; (3) the production of phospholipids with roles in cell and organelle membrane structural integrity as well as novel signaling functions. Dietary deficiency of choline results in deleterious impacts on the liver, muscle, and brain in preclinical and clinical studies. The relationship of dietary choline to health outcomes beyond deficiency prevention, including benefits of maternal choline supplementation for infant cognition, and concerns regarding choline intake's relationship to cardiovascular disease and neurocognitive aging are continued areas of active investigation with need for further research. Choline serves as an important case study for nutritional genomics, owing to the impact of common genetic variants on choline metabolism and requirements, and choline's influence on gene expression.
Preprint
Full-text available
Background: In modern animal husbandry, breeders pay increasing attention to improving sow nutrition during pregnancy and lactation to favor the health of neonates. Sow milk is a main food for piglets during their first three weeks of life, which is not only a rich repository of essential nutrients and a broad range of bioactive compounds, but also an indispensable source of commensal bacteria. Maternal milk microorganisms are important sources of commensal bacteria for neonatal gut. Bacteria from maternal milk may serve as an additive to confer a health benefit on the composition of the indigenous microbiota of piglets. Methods: The sow milk microbiota was collected using the culturomics methods of Continuous Culture and Interval Sampling, following by the identification of 16S rDNA gene sequences. To screen potential probiotics, the functional evaluation was conducted to assess their antagonistic activity against pathogens in vitro and evaluate their resistance against oxidative stress in damaged Drosophila induced by paraquat. In piglet feeding trial, a total of 54 newborn suckling piglets were chosen from nine sows and randomly assigned to three treatments with different concentration of a candidate strain. Multiple approaches were carried out to verify its antioxidant function including western blotting, enzyme activity analysis, metabolomics and 16S rDNA sequencing. Results: The 1240 isolates were screened out from the sow milk microbiota and grouped into 271 bacterial taxa based on a nonredundant set of 16S rDNA gene sequences. Among 80 Pediococcus isolates, a new Pediococcus pentosaceus strain (SMM914) showed best performance in inhibition ability against swine pathogens and in Drosophila model challenged by paraquat. Pretreatment of piglets with SMM914 induces the Nrf2-Keap1 antioxidant signaling pathway and greatly affected the pathways of amino acid metabolism and lipid metabolism in plasma. In colon, Lactobacillus was significantly increased in the high dose of SMM914 group compared with the control group. Conclusion: SMM914 functions as a promising probiotic conferring antioxidant capacity by activating the Nrf2-Keap1 antioxidant signaling pathway in piglets. Our study provided useful resources for deeply understanding the relationships between the maternal microbiota and offspring.
Article
Full-text available
The central aim of this study was to investigate metabolite changes in metabolic pathways via metabonomic approaches in rats suffering from Kidney-Yang Deficiency Syndrome (KYDS) induced by hydrocortisone. Metabonomic analysis using ¹H NMR is a well-established approach for the study of metabolic changes in biofluids. In our study, serum samples were obtained at three specific time points during the progression of KYDS, and individual ¹H NMR spectra were acquired and statistically assessed using two multivariate analyses (MVA): principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA). The profiles on the 15th, 23rd, and 30th day for each sample could be classified, further revealing progression axes from a normal status to KYDS status. Consequently, significant changes in seventeen metabolites, i.e. lactate, valine, alanine, methionine, succinate, glutamine, 3-hydroxybutyrate, creatine, choline, HDL, LDL, VLDL, TMAO, betaine, tyrosine, citrate, and glycerol, were identified. These biochemical changes were found to be directly related to disturbances in energy metabolism, amino acid metabolism, lipid metabolism, choline metabolism, and gut metabolism. We further determined that lactate and the other 16 metabolic markers may be used as specific markers of KYDS over time. Overall, this study demonstrates that this metabonomic method is a valuable tool for studying the pathologic changes of the Chinese medicine syndrome and the underlying mechanisms of KYDS.
Article
Aims: Choline-deficient diet is extensively used as a model of nonalcoholic fatty liver disease (NAFLD). In this study, we explored genes in the liver for which the expression changed in response to the choline-deficient (CD) diet. Main methods: Male CD-1 mice were divided into two groups and fed a CD diet with or without 0.2% choline bitartrate for one or three weeks. Hepatic levels of choline metabolites were analyzed by using liquid chromatography mass spectrometry and hepatic gene expression profiles were examined by DNA microarray analysis. Key findings: The CD diet lowered liver choline metabolites after one week and exacerbated fatty liver between one and three weeks. We identified >300 genes whose expression was significantly altered in the livers of mice after consumption of this CD diet for one week and showed that liver gene expression profiles could be classified into six distinct groups. This study showed that STAT1 and interferon-regulated genes was up-regulated after the CD diet consumption and that the Stat1 mRNA level was negatively correlated with liver phosphatidylcholine level. Stat1 mRNA expression was actually up-regulated in isolated hepatocytes from the mouse liver with the CD diet. Significance: This study provides insight into the genomic effects of the CD diet through the Stat1 expression, which might be involved in NAFLD development.
Article
Full-text available
Tremendous hike in the use of chemicals in every consumables worldwide, led researchers to investigate the effects of various products and their ingredients that are being used in routine. Diethanolamine (DEA) is one such organic compound used in various industries and several personal care products that are being used daily. To evaluate DEA toxicity on nucleic acid content, Swiss strain male albino mice were chosen as animal model for in vivo experiments. Mice were exposed to DEA (110, 165, 330 mg/kg body weight/day) for 30 days. Animals were sorted into nine different groups, each containing 10 animals per group. In untreated control groups of animals no significant changes in nucleic acid content were noted whereas in DEA exposed animals, nucleic acid content decreased significantly (p<0.05) in a dose-dependent manner. However, more decrease were noted in high dose (330 mg/kg body weight/day) exposed animals as compared to other groups of animals. For the mitigation of the toxicity generated by DEA, curcumin, a miraculous antioxidant, which is an active component of turmeric was used. Curcumin (10, 20, 30 mg/kg body weight/day) was orally administered for 30 days along with the high dose of DEA. After completion of treatment, animals were humanly sacrificed and liver was quickly isolated for further biochemical evaluations. In animals exposed to curcumin for 30 days the nucleic acid content increased significantly (p<0.05) as compared to DEA-HD treated groups of animals. The effect was dose-dependent. The ameliorative effect of curcumin might be due to its high antioxidant potency.
Article
Diabetes mellitus (DM) can cause systemic metabolic disorders, but impact of gender on DM-related metabolic changes is rarely reported. Herein, we analyzed metabolic alterations in the heart, liver and kidney of male and female mice from normal to diabetes via a 1H NMR-based metabolomics method, and aimed to investigate sex-specific metabolic mechanisms underlying the onset and development of diabetes and its complications. Our results demonstrate that male mice had more significant metabolic disorders from normal to diabetes than female mice. Moreover, the kidney was found as the major organ of metabolic disorders during the development of diabetes, followed by the liver and heart. These altered metabolites were mainly implicated in energy metabolism as well as amino acid, choline and nucleotide metabolism. Therefore, this study suggests that the kidney was the primary organ affected by diabetes in a sex-specific manner, which provides a metabolic view on the pathogenesis of diabetic kidney diseases between genders.
Article
An 8‐week feeding trial was conducted to evaluate the effects of dietary choline levels on growth performance, antioxidant capacity and lipid metabolites in juvenile Pacific white shrimp. Six isonitrogenous and isolipidic diets were formulated to supply 0, 1,000, 2,000, 4,000, 6,000, 10,000 mg/kg choline chloride, and dietary choline levels were analysed to be 1,317 (basal diet), 1,721, 2,336, 3,294, 5,421 and 9,495 mg/kg, respectively. Dietary choline levels significantly influenced percent weight gain (PWG) and protein efficiency ratio (PER), with the highest PWG was observed in shrimp fed the 5,421 mg/kg choline diet. However, there were no significant differences in proximate composition of whole body and muscle. Shrimp fed the diet containing 2,336 mg/kg choline had lower HDL and LDL in haemolymph than those fed the basal diet (1,317 mg/kg diet). Dietary choline prevented the accumulation of free radicals and improved antioxidant capacity by increasing catalase activity and reducing malondialdehyde content. Based on broken‐line regression and quadratic regression analysis between PWG against dietary choline levels, the optimal choline requirements were estimated to be 3,254.1 and 6,488.3 mg/kg for juvenile L. vannamei, respectively.
Article
Choline oxidase oxidizes choline to glycine betaine, with two flavin-mediated reactions to convert the alcohol substrate to the carbon acid product. Proton abstraction from choline or hydrated betaine aldehyde in the wild-type enzyme occurs in the mixing time of the stopped-flow spectrophotometer, thereby precluding a mechanistic investigation. Mutagenesis of S101 rendered the proton transfer reaction amenable to study. Here, we have investigated the aldehyde oxidation reaction catalyzed by the mutant enzymes using steady-state and rapid kinetics with betaine aldehyde. Stopped-flow traces for the reductive half-reaction of the S101T/V/C variants were biphasic, corresponding to the reactions of proton abstraction and hydride transfer. In contrast, the S101A enzyme yielded monophasic traces like wild-type choline oxidase. The rate constants for proton transfer in the S101T/C/V variants decreased logarithmically with increasing hydrophobicity of residue 101, indicating a behavior different from that seen previously with choline for which no correlation was determined. The rate constants for hydride transfer also showed a logarithmic decrease with increasing hydrophobicity at position 101, which was similar to previous results with choline as a substrate for the enzyme. Thus, the hydrophilic character of S101 is necessary not only for efficient hydride transfer but also for the proton abstraction reaction.
Chapter
Phospholipases D (PLDs) catalyze hydrolysis of the diester bond of phospholipids to generate phosphatidic acid and the free lipid headgroup. In mammals, PLD enzymes comprise the intracellular enzymes PLD1 and PLD2 and possibly the proteins encoded by related genes, as well as a class of cell surface and secreted enzymes with structural homology to ectonucleotide phosphatases/phosphodiesterases as typified by autotaxin (ENPP2) that have lysoPLD activities. Genetic and pharmacological loss-of-function approaches implicate these enzymes in intra- and intercellular signaling mediated by the lipid products phosphatidic acid, lysophosphatidic acid, and their metabolites, while the possibility that the water-soluble product of their reactions is biologically relevant has received far less attention. PLD1 and PLD2 are highly selective for phosphatidylcholine (PC), whereas autotaxin has broader substrate specificity for lysophospholipids but by virtue of the high abundance of lysophosphatidylcholine (LPC) in extracellular fluids predominantly hydrolyses this substrate. In all cases, the water-soluble product of these PLD activities is choline. Although choline can be formed de novo by methylation of phosphatidylethanolamine, this activity is absent in most tissues, so mammals are effectively auxotrophic for choline. Dietary consumption of choline in both free and esterified forms is substantial. Choline is necessary for synthesis of the neurotransmitter acetylcholine and of the choline-containing phospholipids PC and sphingomyelin (SM) and also plays a recently appreciated important role as a methyl donor in the pathways of “one-carbon (1C)” metabolism. This review discusses emerging evidence that some of the biological functions of these intra- and extracellular PLD enzymes involve generation of choline with a particular focus on the possibility that these choline and PLD dependent processes are dysregulated in cancer.
Article
Background and Purpose Choline metabolism was suggested to play pathophysiological roles in nervous system and atherosclerosis development. However, little is known about the impacts of choline pathway nutrients and metabolites on poststroke cognitive impairment. We aimed to prospectively investigate the relationships between circulating choline, betaine, and trimethylamine N-oxide with cognitive impairment among acute ischemic stroke patients. Methods We derived data from CATIS (China Antihypertensive Trial in Acute Ischemic Stroke). Plasma choline, betaine, and trimethylamine N-oxide concentrations at baseline were measured in 617 participants. Cognitive impairment was evaluated using the Mini-Mental State Examination and the Montreal Cognitive Assessment. Reclassification and calibration of models with choline-related biomarkers were evaluated. Results Plasma choline and betaine were inversely associated with cognitive impairment. Compared with the lowest tertile, adjusted odds ratios of Mini-Mental State Examination–defined cognitive impairment for participants in the highest tertiles of choline and betaine were 0.59 (95% CI, 0.39–0.90) and 0.60 (95% CI, 0.39–0.92), respectively. In addition, both choline and betaine offered incremental predictive ability over the basic model with established risk factors, shown by increase in net reclassification improvement and integrated discrimination improvement. There were similar significant relationships between choline and betaine with cognitive impairment as defined by the Montreal Cognitive Assessment. However, plasma trimethylamine N-oxide was only associated with cognitive impairment evaluated using the Mini-Mental State Examination; the adjusted odds ratio was 1.33 (95% CI, 1.04–1.72) for each 1-SD increment of trimethylamine N-oxide. Conclusions Patients with higher choline and betaine levels had lower risk of cognitive impairment after ischemic stroke, supporting promising prognostic roles of choline pathway nutrients for poststroke cognitive impairment.
Article
Background: Artemisinin-resistance has inevitably emerged in several epidemic areas and led to an incremental clinical failure rate for artemisinin based combination therapy (ACTs) strongly recommended by World Health Organization (WHO). The genetically resilient malaria parasites have evolved anti-malarial drugs evasion mechanisms, meanwhile, the metabolic cross-talk between the malarial parasites and the parasitifer is of significance during the invasion. The intention of this work, therefore, is to propose a feasible method to discover the systematic metabolic phenotypes of mice invaded with artemisinin-sensitive or -resistant Plasmodium berghei K173 when compared with healthy mice. Methods: Collected biological samples including plasma, liver, spleen, and kidney samples of mice after euthanasia at day 7 were subjected to 1 H nuclear magnetic resonance spectroscopy (NMR). Multivariable data analysis (MVDA) means were utilized to estimate the metabolic characteristics of these samples from uninfected and infected mice. Results: In contrast with healthy mice, both sensitive and resistant malarial parasites infected models displayed distinct metabolic profiles. Parasites invasion significantly changed glucolysis, Kreb’s cycle, and amino acids metabolism in plasma and tissues. Decreased N, N-dimethylglycine, and glycine levels in plasma from artemisinin-sensitive P. berghei infected group and increased lactate, lipids, and aspartate in artemisinin-resistant P. berghei infected group were observed, respectively. In the liver, artemisinin-sensitive group up-regulated glutamate level and down-regulated glutamine. Artemisinin-resistant parasites exposure decreased ethanol and allantoin levels. The levels of myo-Inositol and valine in the spleen were increased due to artemisinin-sensitive P. berghei infection together with decreased trimethylamine N-oxide, phosphocholine, beta-glucose, and acetoacetic acid. In the artemisinin-resistant group, the spleen showed a remarkably increased phosphocholine content along with decreased dimethylglycine and arginine levels. In the kidney, artemisinin-sensitive P. Berghei K173 caused an ascended lysine, glutamate, creatine, and 2-Hydroxybutyrate as well as descended ethanol. Artemisinin-resistant P. berghei led to low glycerophosphorylcholine and high acetate, betaine, and hypoxanthine. Mutual and specific altered metabolites and accordingly metabolic pathways induced by the infection of artemisinin-sensitive or -resistant P. berghei were therefore screened out. Conclusions: This study might be a preliminary study to establish a direct relationship with the host metabolic background and artemisinin-resistance.
Article
Deficiencies in methyl donor status may render DNA methylation changes and DNA damage, leading to carcinogenesis. Epidemiological studies reported that higher dietary intake of choline is associated with lower risk of pancreatic cancer, but no study has examined the association of serum choline and its metabolites with risk of pancreatic cancer. Two parallel case–control studies, one nested within the Shanghai Cohort Study (129 cases and 258 controls) and the other within the Singapore Chinese Health Study (58 cases and 104 controls), were conducted to evaluate the associations of baseline serum concentrations of choline, betaine, methionine, total methyl donors (i.e., sum of choline, betaine and methionine), dimethylglycine and trimethylamine N‐oxide (TMAO) with pancreatic cancer risk. In the Shanghai cohort, odds ratios and 95% confidence intervals of pancreatic cancer for the highest quartile of choline, betaine, methionine, total methyl donors, and TMAO were 0.27 (0.11–0.69), 0.57 (0.31–1.05), 0.50 (0.26–0.96), 0.37 (0.19–0.73), and 2.81 (1.37–5.76), respectively, compared to the lowest quartile. The corresponding figures in the Singapore cohort were 0.85 (0.23–3.17), 0.50 (0.17–1.45), 0.17 (0.04–0.68), 0.33 (0.10–1.16), and 1.42 (0.50–4.04). The inverse associations of methionine and total methyl donors including choline, betaine and methionine with pancreatic cancer risk in both cohorts support that DNA repair and methylation play an important role against the development of pancreatic cancer. In the Shanghai cohort, TMAO, a gut microbiota‐derived metabolite of dietary phosphatidylcholine, may contribute to higher risk of pancreatic cancer, suggesting a modifying role of gut microbiota in the dietary choline‐pancreatic cancer risk association. This article is protected by copyright. All rights reserved.
Article
When considering neurodevelopmental disorders (NDDs), Schizophrenia (SZ) and Autism Spectrum Disorder (ASD) are considered to be among the most severe in term of prevalence, morbidity and impact on the society. Similar features and overlapping symptoms have been observed at multiple levels, suggesting common pathophysiological bases. Indeed, recent genome-wide association studies (GWAS) and epidemiological data report shared vulnerability genes and environmental triggers across the two disorders. In this review, we will discuss the possible biological mechanisms, including glutamatergic and GABAergic neurotransmissions, inflammatory signals and oxidative stress related systems, which are targeted by adverse environmental exposures and that have been associated with the development of SZ and ASD. We will also discuss the emerging role of the gut microbiome as possible interplay between environment, immune system and brain development. Finally, we will describe the involvement of epigenetic mechanisms in the maintenance of long-lasting effects of adverse environments early in life. This will allow us to better understand the pathophysiology of these NDDs, and also to identify novel targets for future treatment strategies.
Article
Defect in one-carbon metabolism is one of the multiple underlying pathological pathways contributing to NAFLD pathogenesis. Hence, our study was designed to examine whether different one-carbon donors; betaine, choline, and folic acid would possess beneficial effects in NAFLD treatment. Rats were fed with high fat diet and NAFLD rats were orally treated with different doses of betaine or choline or folic acid for 28 days. All used one-carbon donors had dose-dependent ameliorating effects on NAFLD as they succeeded to reduce body and relative liver weights, serum lipids and liver enzymes. These were accompanied by decreasing hepatic fat accumulation and amending hepatic histological structure. They also improved serum and hepatic redox systems (total glutathione (tGSH), reduced GSH, oxidized GSSG, and GSH/GSSG ratio), hepatic S-adenosylmethionine/S-adenosyl homocysteine (SAM/SAH) ratio and increased hepatic global DNA methylation. There were some discrepancies in the dose and the extent of their effect, where folic acid showed the most prominent effects that could be mediated through the significant surge in hepatic SAM/SAH ratio and better efficient correction of one-carbon metabolism than the other donors. Thus, one-carbon donors can be strongly considered in NAFLD management and might influence the whole therapeutic approaches of fatty liver diseases.
Article
Full-text available
Article
Full-text available
Folate deficiency causes massive incorporation of uracil into human DNA (4 million per cell) and chromosome breaks. The likely mechanism is the deficient methylation of dUMP to dTMP and subsequent incorporation of uracil into DNA by DNA polymerase. During repair of uracil in DNA, transient nicks are formed; two opposing nicks could lead to chromosome breaks. Both high DNA uracil levels and elevated micronucleus frequency (a measure of chromosome breaks) are reversed by folate administration. A significant proportion of the U.S. population has low folate levels, in the range associated with elevated uracil misincorporation and chromosome breaks. Such breaks could contribute to the increased risk of cancer and cognitive defects associated with folate deficiency in humans.
Article
Full-text available
DNA methyltransferase 1 (DNMT1) maintains methylation at CpG dinucleotides, important for transcriptional silencing at many loci. It is also implicated in stabilizing repeat sequences: DNMT1 deficiency causes microsatellite instability in mouse embryonic stem cells, but it is unclear how this occurs, how repeats lacking CpG become unstable and whether the effect is confined to stem cells. To address these questions, we transfected hTERT-immortalized normal human fibroblasts (hTERT-1604) with a short hairpin RNA construct targeting DNMT1 and isolated stable integrants with different levels of protein. DNMT1 expression levels agreed well with methylation levels at imprinted genes. Knockdown cells showed two key characteristics of mismatch repair (MMR) deficiency, namely resistance to the drug 6-thioguanine and up to 10-fold elevated mutation rates at a CA(17) microsatellite reporter, but had limited viability. The likely cause of MMR defects is a matching drop in steady-state protein levels for key repair components in DNMT1 knockdown cells, affecting both the MutLα and MutSα complexes. This indirect effect on MMR proteins was also seen using a different targeting method in HT29 colon cancer cells and did not involve transcriptional silencing of the respective genes. Decreased levels of MMR components follow activation of the DNA damage response and blocking this response, and in particular poly(ADP-ribose) polymerase (PARP) overactivation, rescues cell viability in DNMT1-depleted cells. These results offer an explanation for how and why unmethylated microsatellite repeats can be destabilized in cells with decreased DNMT1 levels and uncover a novel and important role for PARP in this process.
Article
Full-text available
Dot1L, a histone methyltransferase that targets histone H3 lysine 79 (H3K79), has been implicated in gene regulation and the DNA damage response although its functions in these processes remain poorly defined. Using the chicken DT40 model system, we generated cells in which the Dot1L gene is disrupted to examine the function and focal recruitment of the 53Bp1 DNA damage response protein. Detailed kinetic and dose response assays demonstrate that, despite the absence of H3K79 methylation demonstrated by mass spectrometry, 53Bp1 focal recruitment is not compromised in these cells. We also describe, for the first time, the phenotypes of a cell line lacking both Dot1L and 53Bp1. Dot1L⁻/⁻ and wild type cells are equally resistant to ionising radiation, whereas 53Bp1⁻/⁻/Dot1L⁻/⁻ cells display a striking DNA damage resistance phenotype. Dot1L and 53Bp1 also affect the expression of many genes. Loss of Dot1L activity dramatically alters the mRNA levels of over 1200 genes involved in diverse biological functions. These results, combined with the previously reported list of differentially expressed genes in mouse ES cells knocked down for Dot1L, demonstrates surprising cell type and species conservation of Dot1L-dependent gene expression. In 53Bp1⁻/⁻ cells, over 300 genes, many with functions in immune responses and apoptosis, were differentially expressed. To date, this is the first global analysis of gene expression in a 53Bp1-deficient cell line. Taken together, our results uncover a negative role for Dot1L and H3K79 methylation in the DNA damage response in the absence of 53Bp1. They also enlighten the roles of Dot1L and 53Bp1 in gene expression and the control of DNA double-strand repair pathways in the context of chromatin.
Article
Full-text available
Given its significant role in the maintenance of genomic stability, histone methylation has been postulated to regulate DNA repair. Histone methylation mediates localization of 53BP1 to a DNA double-strand break (DSB) during homologous recombination repair, but a role in DSB repair by nonhomologous end-joining (NHEJ) has not been defined. By screening for histone methylation after DSB induction by ionizing radiation we found that generation of dimethyl histone H3 lysine 36 (H3K36me2) was the major event. Using a novel human cell system that rapidly generates a single defined DSB in the vast majority of cells, we found that the DNA repair protein Metnase (also SETMAR), which has a SET histone methylase domain, localized to an induced DSB and directly mediated the formation of H3K36me2 near the induced DSB. This dimethylation of H3K36 improved the association of early DNA repair components, including NBS1 and Ku70, with the induced DSB, and enhanced DSB repair. In addition, expression of JHDM1a (an H3K36me2 demethylase) or histone H3 in which K36 was mutated to A36 or R36 to prevent H3K36me2 formation decreased the association of early NHEJ repair components with an induced DSB and decreased DSB repair. Thus, these experiments define a histone methylation event that enhances DNA DSB repair by NHEJ.
Article
Full-text available
When dietary choline is restricted, most men and postmenopausal women develop multiorgan dysfunction marked by hepatic steatosis (choline deficiency syndrome (CDS)). However, a significant subset of premenopausal women is protected from CDS. Because hepatic PEMT (phosphatidylethanolamine N-methyltransferase) catalyzes de novo biosynthesis of choline and this gene is under estrogenic control, we hypothesized that there are SNPs in PEMT that disrupt the hormonal regulation of PEMT and thereby put women at risk for CDS. In this study, we performed transcript-specific gene expression analysis, which revealed that estrogen regulates PEMT in an isoform-specific fashion. Locus-wide SNP analysis identified a risk-associated haplotype that was selectively associated with loss of hormonal activation. Chromatin immunoprecipitation, analyzed by locus-wide microarray studies, comprehensively identified regions of estrogen receptor binding in PEMT. The polymorphism (rs12325817) most highly linked with the development of CDS (p < 0.00006) was located within 1 kb of the critical estrogen response element. The risk allele failed to bind either the estrogen receptor or the pioneer factor FOXA1. These data demonstrate that allele-specific ablation of estrogen receptor-DNA interaction in the PEMT locus prevents hormone-inducible PEMT expression, conferring risk of CDS in women.
Article
Full-text available
Choline is obtained from the diet and from the biosynthesis of phosphatidylcholine. Phosphatidylcholine is catalyzed by the enzyme phosphatidylethanolamine-N-methyltransferase (PEMT), which is induced by estrogen. Because they have lower estrogen concentrations, postmenopausal women are more susceptible to the risk of organ dysfunction in response to a low-choline diet. A common genetic polymorphism (rs12325817) in the PEMT gene can also increase this risk. The objective was to determine whether the risk of low choline-related organ dysfunction increases with the number of alleles of rs12325817 in premenopausal women and whether postmenopausal women (with or without rs12325817) treated with estrogen are more resistant to developing such symptoms. Premenopausal women (n = 27) consumed a choline-sufficient diet followed by a very-low-choline diet until they developed organ dysfunction (or for 42 d), which was followed by a high-choline diet. Postmenopausal women (n = 22) were placed on the same diets but were first randomly assigned to receive estrogen or a placebo. The women were monitored for organ dysfunction and plasma choline metabolites and were genotyped for rs12325817. A dose-response effect of rs12325817 on the risk of choline-related organ dysfunction was observed in premenopausal women: 80%, 43%, and 13% of women with 2, 1, or 0 alleles, respectively, developed organ dysfunction. Among postmenopausal women, 73% who received placebo but only 18% who received estrogen developed organ dysfunction during the low-choline diet. Because of their lower estrogen concentrations, postmenopausal women have a higher dietary requirement for choline than do premenopausal women. Choline requirements for both groups of women are further increased by rs12325817. This trial was registered at clinicaltrials.gov as NCT00065546.
Article
Full-text available
Choline dehydrogenase (CHDH) catalyzes the conversion of choline to betaine, an important methyl donor and organic osmolyte. We have previously identified single nucleotide polymorphisms (SNPs) in the human CHDH gene that, when present, seem to alter the activity of the CHDH enzyme. These SNPs occur frequently in humans. We created a Chdh(-/-) mouse to determine the functional effects of mutations that result in decreased CHDH activity. Chdh deletion did not affect fetal viability or alter growth or survival of these mice. Only one of eleven Chdh(-/-) males was able to reproduce. Loss of CHDH activity resulted in decreased testicular betaine and increased choline and PCho concentrations. Chdh(+/+) and Chdh(-/-) mice produced comparable amounts of sperm; the impaired fertility was due to diminished sperm motility in the Chdh(-/-) males. Transmission electron microscopy revealed abnormal mitochondrial morphology in Chdh(-/-) sperm. ATP content, total mitochondrial dehydrogenase activity and inner mitochondrial membrane polarization were all significantly reduced in sperm from Chdh(-/-) animals. Mitochondrial changes were also detected in liver, kidney, heart, and testis tissues. We suggest that men who have SNPs in CHDH that decrease the activity of the CHDH enzyme could have decreased sperm motility and fertility.
Article
Full-text available
Dietary choline deprivation (CD) is associated with behavioral changes, but mechanisms underlying these detrimental effects are not well characterized. For instance, no literature data are available concerning the CD effects on brain mitochondrial function related to impairment in cognition. Therefore, we investigated brain mitochondrial function and redox status in male Wistar rats fed a CD diet for 28 d. Moreover, the CD behavioral phenotype was characterized. Compared with rats fed a control diet (CTRL), CD rats showed lower NAD-dependent mitochondrial state III and state IV respiration, 40% lower complex I activity, and significantly higher reactive oxygen species production. Total glutathione was oxidatively consumed more in CD than in CTRL rats and the rate of protein oxidation was 40% higher in CD than in CTRL rats, reflecting an oxidative stress condition. The mitochondrial concentrations of cardiolipin, a phospholipid required for optimal activity of complex I, was 20% lower in CD rats than in CTRL rats. Compared with CTRL rats, the behavioral phenotype of CD rats was characterized by impairment in motor coordination and motor learning assessed with the rotarod/accelerod test. Furthermore, compared with CTRL rats, CD rats were less capable of learning the active avoidance task and the number of attempts they made to avoid foot shock was fewer. The results suggest that CD-induced dysfunction in brain mitochondria may be responsible for impairment in cognition and underline that, similar to the liver, the brain also needs an adequate choline supply for its normal functioning.
Article
Full-text available
Maternal choline availability is essential for fetal neurogenesis. Choline deprivation (CD) causes hypomethylation of specific CpG islands in genes controlling cell cycling in fetal hippocampus. We now report that, in C57BL/6 mice, CD during gestational days 12-17 also altered methylation of the histone H3 in E17 fetal hippocampi. In the ventricular and subventricular zones, monomethyl-lysine 9 of H3 (H3K9me1) was decreased by 25% (P<0.01), and in the pyramidal layer, dimethyl-lysine 9 of H3 (H3K9me2) was decreased by 37% (P<0.05). These changes were region specific and were not observed in whole-brain preparations. Also, the same effects of CD on H3 methylation were observed in E14 neural progenitor cells (NPCs) in culture. Changes in G9a histone methyltransferase might mediate altered H3K9me2,1. Gene expression of G9a was decreased by 80% in CD NPCs (P<0.001). In CD, H3 was hypomethylated upstream of the RE1 binding site in the calbindin 1 promoter, and 1 CpG site within the calbindin1 promoter was hypermethylated. REST binding to RE1 (recruits G9a) was decreased by 45% (P<0.01) in CD. These changes resulted in increased expression of calbindin 1 in CD (260%; P<0.05). Thus, CD modulates histone methylation in NPCs, and this could underlie the observed changes in neurogenesis.
Article
Full-text available
Choline and betaine provide methyl groups for one-carbon metabolism. Humans obtain these nutrients from a wide range of foods. Betaine can also be synthesized endogenously from its precursor, choline. Although animal studies have implied a causal relationship between choline deficiency and carcinogenesis, the role of these two nutrients in human carcinogenesis and tumor progression is not well understood. We investigated the associations of dietary intakes of choline and betaine and breast cancer risk and mortality in the population-based Long Island Breast Cancer Study Project. Among the 1508 case-group women, 308 (20.2%) deaths occurred, among whom 164 (53.2%) died of breast cancer by December 31, 2005. There was an indication that a higher intake of free choline was associated with reduced risk of breast cancer (P(trend)=0.04). Higher intakes of betaine, phosphocholine, and free choline were associated with reduced all-cause as well as breast cancer-specific mortality in a dose-dependent fashion. We also explored associations of polymorphisms of three key choline- and betaine-metabolizing genes and breast cancer mortality. The betaine-homocysteine methyltransferase gene (BHMT) rs3733890 polymorphism was associated with reduced breast cancer-specific mortality (hazard ratio, 0.64; 95% confidence interval, 0.42-0.97). Our study supports the important roles of choline and betaine in breast carcinogenesis. It suggests that high intake of these nutrients may be a promising strategy to prevent the development of breast cancer and to reduce its mortality.
Article
Full-text available
The repeatability of a risk factor measurement affects the ability to accurately ascertain its association with a specific outcome. Choline is involved in methylation of homocysteine, a putative risk factor for cardiovascular disease, to methionine through a betaine-dependent pathway (one-carbon metabolism). It is unknown whether dietary intake of choline meets the recommended Adequate Intake (AI) proposed for choline (550 mg/day for men and 425 mg/day for women). The Estimated Average Requirement (EAR) remains to be established in population settings. Our objectives were to ascertain the reliability of choline and related nutrients (folate and methionine) intakes assessed with a brief food frequency questionnaire (FFQ) and to estimate dietary intake of choline and betaine in a bi-ethnic population. We estimated the FFQ dietary instrument reliability for the Atherosclerosis Risk in Communities (ARIC) study and the measurement error for choline and related nutrients from a stratified random sample of the ARIC study participants at the second visit, 1990-92 (N = 1,004). In ARIC, a population-based cohort of 15,792 men and women aged 45-64 years (1987-89) recruited at four locales in the U.S., diet was assessed in 15,706 baseline study participants using a version of the Willett 61-item FFQ, expanded to include some ethnic foods. Intraindividual variability for choline, folate and methionine were estimated using mixed models regression. Measurement error was substantial for the nutrients considered. The reliability coefficients were 0.50 for choline (0.50 for choline plus betaine), 0.53 for folate, 0.48 for methionine and 0.43 for total energy intake. In the ARIC population, the median and the 75th percentile of dietary choline intake were 284 mg/day and 367 mg/day, respectively. 94% of men and 89% of women had an intake of choline below that proposed as AI. African Americans had a lower dietary intake of choline in both genders. The three-year reliability of reported dietary intake was similar for choline and related nutrients, in the range as that published in the literature for other micronutrients. Using a brief FFQ to estimate intake, the majority of individuals in the ARIC cohort had an intake of choline below the values proposed as AI.
Article
Full-text available
More than 60% of all breast neoplasias are ductal carcinomas expressing estrogen (ER) and progesterone receptors (PR). By contrast, most of the spontaneous, chemically or mouse mammary tumor virus induced tumors, as well as tumors arising in genetically modified mice do not express hormone receptors. We developed a model of breast cancer in which the administration of medroxyprogesterone acetate to BALB/c female mice induces mammary ductal carcinomas with a mean latency of 52 weeks and an incidence of about 80%. These tumors are hormone-dependent (HD), metastatic, express both ER and PR, and are maintained by syngeneic transplants. The model has been further refined to include mammary carcinomas that evolve through different stages of hormone dependence, as well as several hormone-responsive cell lines. In this review, we describe the main features of this tumor model, highlighting the role of PR as a trigger of key signaling pathways mediating tumor growth. In addition, we discuss the relevance of this model in comparison with other presently used breast cancer models pointing out its advantages and limitations and how, this model may be suitable to unravel key questions in breast cancer.
Article
Full-text available
The carcinogenicities of a choline deficient L-amino acid defined (CDAA) diet and a semipurified choline deficient diet were comparatively examined. A total of 60 male Fischer 344 rats, 6 weeks old, were divided into 5 experimental groups each consisting of 12 rats. Group 1 received the CDAA diet chronically to the end of the 52-week experiment while Group 2 was given the same diet for the first 24 weeks and then a basal diet for the following 28 weeks. Groups 3, 4, and 5 received a choline supplemented L-amino acid defined diet, the semipurified choline deficient diet, and a semipurified choline supplemented diet, respectively, throughout the experimental period. All surviving rats were subjected to complete macroscopic examination at Week 52. Histopathologically diagnosed hepatocellular carcinomas were induced in Group 1 at an incidence of 100%; multiple metastatic nodules were seen in the lungs of one of the animals. Hepatocellular carcinomas were also induced in Group 4 rats at a significantly lower incidence of 20%. No hepatocellular carcinomas were observed in rats in Groups 2, 3, and 4. The results indicate that the CDAA diet exerts more potent carcinogenicity for the livers of rats than does the semipurified choline deficient diet. However, limited exposure for 24 weeks may have not been sufficient for hepatocellular carcinoma induction by the CDAA diet at Week 52 although a high incidence of hyperplastic nodules and slight cirrhosis were evidence of persistent lesions.
Article
Full-text available
Hepatic mitochondrial and peroxisomal oxidative capacities were studied in young (4-5 weeks old) and adult (6-9 months old) lean and obese ob/ob mice that were fed or starved for 24 or 48 h. The adult obese mice showed elevated capacity for mitochondrial oxidation (ng-atoms of O consumed/min per mg of protein) of lipid and non-lipid substrates, with the exception of pyruvate + malate, and elevated activities of citrate synthase and total carnitine palmitoyltransferase. Oxidative rates and enzyme activities were not affected by starvation of lean or obese mice, and both males and females responded similarly. Peroxisomal palmitoyl-CoA oxidation (nmol/min per mg of peroxisomal protein) was also increased in livers of adult obese mice and did not change with starvation. In young mice, hepatic mitochondrial and peroxisomal oxidative capacities in lean and obese mice were comparable. The increased mitochondrial and peroxisomal oxidative capacities appear to develop with maturation in obese ob/ob mice.
Article
Full-text available
Thymidylate synthase-negative mutants of cultured mouse cells were immediately committed to cell death upon thymidine deprivation, especially when the cells were synchronized in the S phase. Thymidylate deprivation induced single strand breaks in chromosome-size DNA strands, as measured by alkaline sucrose gradient sedimentation, giving rise to two peaks, one with large and the other with small fragments, the latter about the size of T4 DNA. An increase in the small DNA fragments paralleled that of thymineless death. Thymidine deprivation also produced double strand DNA fragments as determined by a method of neutral filter elution, and their extent paralleled that of cell death. Double-stranded DNA eluted through the filter sedimented as a single peak both in a neutral and in an alkaline sucrose gradient that coincided with that of the above small DNA fragments. Therefore, the strand breaks seemed to occur in some defined portions of the genome and in a specific manner compared to breaks induced by x-rays, which occurred rather randomly. Cycloheximide blocked both thymineless death and the production of the small DNA fragments. The strand breaks induced by thymidine starvation were not repaired but instead advanced on subsequent incubation of the cells in growth medium containing thymidine.
Article
Full-text available
The expression of rat liver phosphatidylethanolamine N-methyltransferase-2 (PEMT2) in McA-RH7777 rat hepatoma cells resulted in the unexpected inhibition of cell growth. There was a strict correlation (r = 0.973) between the level of expression of the enzyme activity and the generation time for hepatoma cell division. Expression of other foreign proteins via the same vector did not inhibit McA-RH7777 cell growth; thus, retardation of cell division was specific for the methyltransferase. Addition of 1 microM 3-deazaadenosine, which causes inhibition of phosphatidylethanolamine methylation, reversed the PEMT2-mediated inhibition of cell division. Transfection of a line of Chinese hamster ovary cells with PEMT2 had no effect on the division of these cells. Induction of hepatic tumors in rats with N-nitrosodiethylamine coincided with a striking decrease in methyltransferase activity and immunoreactive protein in the tumor nodules. Thus, data from studies in cell culture and intact rats suggest a regulatory role for PEMT2 in hepatocyte cell growth and possibly in the development of liver cancer.
Article
Full-text available
It has previously been shown that choline deficiency causes depletion of hepatic folate concentration in rats. Two separate experiments were undertaken to investigate the converse phenomenon: whether folate deficiency would lead to depletion of hepatic choline. In Experiment 1, severe folate deficiency was induced in rats by feeding an amino acid-defined diet containing (per kg diet) 1.4 g choline, 0 mg folate and 10 g succinylsulfathiazole. Control rats were fed the same diet containing 8 mg folate/kg. After 4 wk, plasma and hepatic folate concentrations were significantly depleted in the severely folate-deficient rats compared with controls (P < 0.001), and hepatic choline and phosphocholine concentrations were 65 and 80% lower, respectively (P < 0.001). In Experiment 2, moderate folate deficiency was induced in rats by feeding the same diet as described above, but with the succinylsulfathiazole omitted. After 24 wk, significant systemic folate deficiency was present in the moderately folate-deficient rats compared with controls (P < 0.001). A modest reduction (36%, P = 0.087) in hepatic choline concentration was observed in the moderately folate-deficient rats compared with controls. No significant differences in hepatic phosphocholine concentrations were detected between the two groups. These results indicate that severe folate deficiency causes secondary hepatic choline deficiency in rats.
Article
Full-text available
In our preceding paper, we reported that a temperature-sensitive Chinese hamster ovary cell mutant, PGS-S, with thermolabile phosphatidylglycerophosphate synthase was defective in the biogenesis of both phosphatidylglycerol and cardiolipin (CL) at a nonpermissive temperature (Ohtsuka, T., Nishijima, M., and Akamatsu, Y. (1993) J. Biol. Chem. 268, 22908-22913). To investigate the biological role of cardiolipin, we examined the structure and function of mitochondria in mutant PGS-S cells, since CL is primarily found in the mitochondrial membranes of eukaryotic cells. Under conditions where the formation of CL was impaired, this mutant had both morphological and functional mitochondrial abnormalities, manifested by more stringent temperature sensitivity for cell growth in glucose-deficient medium and by reduced ATP production, increased glycolysis, and reduced oxygen consumption in intact cells. Rotenone-sensitive NADH oxidase activity in cell extracts was also reduced in the mutant cultivated at a nonpermissive temperature, showing a defect(s) in the respiratory electron transport chain of mitochondria. Of the respiratory chain complexes, rotenone-sensitive NADH-ubiquinone reductase (Complex I) was most severely impaired in the mutant, whereas its activity was restored in a revertant of the mutant that had regained the ability to synthesize CL. These results suggest that CL plays a critical role in mitochondrial functions, at least in the respiratory electron transport chain.
Article
Full-text available
In summary there is a wealth of information on dietary and nutritional effects on carcinogenesis in laboratory rodents. Experimental studies based on epidemiological evidence, earlier experimental studies and known or predicted cellular, biochemical and molecular effects of nutrients have produced clear evidence that carcinogenesis in laboratory rodents is influenced by dietary intake of calories, fat, lipotropes (choline, methionine), vitamin A and related retinoids, Se, calcium, zinc, fiber, ethanol and a large number of non-nutrient components of foods. For these substances or groups of substances mechanistic hypotheses supported by experimental data and are leading to further research. The information provided will contribute to understanding of basic processes in carcinogenesis as well as of the specific interactions studied, and should contribute to significant advances in preventive medicine. Restriction of caloric intake of rodents by amounts > 10% over a significant portion of their lifetime reduces tumorigenesis. That level of restriction reduces the rate of growth and maturation, and most experiments in this area employ greater restrictions that virtually abolish growth from a young age. Therefore, the observations are of interest in mechanistic studies, but their applicability to preventive medicine requires better definition of the degree and duration of restriction required for a significant effect and the age at which it must be imposed. Restriction of total fat intake and modifications to increase the intake of omega-3 fats have a reasonably consistent effect on tumorigenesis in rodents but a much less consistently demonstrable effect in humans. Again, the observations in rodents are providing a major stimulus to mechanistic studies. The lipotropes are extremely valuable as tools for investigating mechanisms of carcinogenesis in rodents. Their importance in the epidemiology of human cancer has yet to be demonstrated clearly and is a subject of research at present. The naturally occurring vitamins and minerals, as well as fiber, derive their importance in this context from investigations to explain the consistent epidemiological demonstrations of reduction of tumor risk with increased consumption of fruits and vegetables. The activity of the isolated nutrients as anticarcinogens in rodents has generally not matched the activity expected from epidemiological studies. The anticarcinogenic activity of many of the non-nutrient components of fruits and vegetables is remarkable in particular models, however, as is the activity of natural and synthetic retinoids. At present the results must be interpreted to indicate an important effect of combinations of the whole foods with identification of particular nutrients or non-nutrients in specific cases.(ABSTRACT TRUNCATED AT 400 WORDS)
Article
Full-text available
Choline deficiency, via deprivation of labile methyl groups, is associated with a greatly increased incidence of hepatocarcinoma in experimental animals. This dietary deficiency also causes fatty liver, because choline is needed for hepatic secretion of lipoproteins. We hypothesized that fatty liver might be associated with the accumulation of 1,2-sn-diradylglycerol and subsequent activation of protein kinase C. Several lines of evidence indicate that cancers might develop secondary to abnormalities in protein kinase C-mediated signal transduction. We observed that rats fed a choline-deficient diet for 1, 6, or 27 weeks had increased hepatic concentrations of 1,2-diradylglycerol. At 1 and 6 weeks, hepatic plasma membrane from choline-deficient rats had increased concentrations of 1,2-sn-diacylglycerol and 1-alkyl, 2-acylglycerol, with the latter accounting for 20-26% of membrane 1,2-sn-diradylglycerol (as compared with only 2-5% in controls). Protein kinase C activity was increased in hepatic plasma membrane at 1 week of choline deficiency. By Western blotting there was an increase in the amount of protein kinase C zeta and a decrease in the amount of protein kinase C delta in liver at 1 week. By 6 weeks of choline deficiency, hepatic plasma membrane and cytosolic protein kinase C (PKC) activities were increased significantly, with increased amounts of hepatic plasma membrane protein kinase C alpha, and delta detected by Western blotting. Glycogen synthase activity in liver was diminished after 1 week of choline deficiency; this enzyme is inhibited by PKC-mediated phosphorylation. We suggest that choline deficiency perturbed PKC-mediated transmembrane signaling within liver and that this contributed to the development of hepatic cancer in these animals.
Article
Full-text available
Immortalized CWSV-1 rat hepatocytes, in which p53 protein is inactivated by SV40 large T antigen, had increased numbers of cells with strand breaks in genomic DNA (terminal dUTP end labeling) when grown in 0 Micron choline (67-73% of cells) than when grown in 70 Micron choline (2-3% of cells). Internucleosomal fragmentation of DNA (DNA ladders) was detected in cells grown with 5 Micron and 0 Micron choline for 72h. Cells treated with 0 or 5 Micron choline for 72h detached from the substrate in high numbers (58% of choline deficient cells vs. 1.4% of choline sufficient cells detached) exhibited a high incidence of apoptosis (apoptotic bodies were seen in 55-75% of cells; 67-73% had DNA strand breaks), and an absence of mitosis and proliferating cell nuclear antigen (PCNA) expression. Cells undergoing DNA fragmentation had functioning mitochondria. At 24h, cells grown in 0 or 5 Micron choline synthesize DNA more rapidly than those grown in 70 Micron choline. By 72h, the cells grown in 0 or 5 Micron choline were forming DNA much more slowly than control cells (assessed by thymidine incorporation, PCNA expression, and mitotic index). Western blot analysis showed that p53 in the nucleus of cells was detected in direct association with SV40 T-antigen, and was therefore likely to be inactive. We conclude that choline deficiency kills CWSV-1 hepatocytes in culture by inducing apoptosis via what may be a p53-independent process, and that this process begins in viable cells before they detach from the culture dish.
Article
The mechanism of induction of apoptosis by the novel anti-cancer drug 1-O-octadecyl-2-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3) was investigated in p53-defective SV40 immortalized rat hepatocytes (CWSV1). Exposure to 12 μM ET-18-OCH3 for 36 h induced apoptosis as determined using classical morphological features and agarose gel electrophoresis of genomic DNA. Increased levels of reactive oxygen species (ROS) were detected spectrophotometrically using a nitroblue tetrazolium (NBT) assay in cells treated with ET-18-OCH3. Both the increased generation of ROS and the induction of apoptosis were inhibited when cells were treated concurrently with ET-18-OCH3 in the presence of the antioxidant α-tocopherol. Similar results were achieved when cells were switched acutely to choline-deficient (CD) medium in the presence of the antioxidant. The possible role of mitochondria in the generation of ROS was investigated. Both ET-18-OCH3 and CD decreased the phosphatidylcholine (PC) content of mitochondrial and associated membranes, which correlated with depolarization of the mitochondrial membrane as analyzed using 5,5′,6,6′-tetramethylbenzimidazolcarbocyanine iodide (JC-1), a sensitive probe of mitochondrial membrane potential. Rotenone, an inhibitor of the mitochondrial electron transport chain, significantly reduced the intracellular level of ROS and prevented mitochondrial membrane depolarization, correlating with a reduction of apoptosis in response to either ET-18-OCH3 or CD. Taken together, these results suggest that the form of p53-independent apoptosis induced by ET-18-OCH3 is mediated by alterations in mitochondrial membrane PC, a loss of mitochondrial membrane potential, and the release of ROS, resulting in completion of apoptosis.—Vrablic, A. S., Albright, C. D., Craciunescu, C. N., Salganik, R. I., Zeisel, S. H. Altered mitochondrial function and overgeneration of reactive oxygen species precede the induction of apoptosis by 1-O-octadecyl-2-methyl-rac-glycero-3-phosphocholine in p53-defective hepatocytes.
Article
We have previously reported that folate and choline metabolism are interrelated. Total folate concentration was significantly diminished (31%) when rats were fed a choline-deficient diet for 2 weeks. Distribution among species of folates (differing in pteridine ring structure and/or in the number of glutamic acid residues) was not altered by this short-term dietary deficiency. In the present study we analyzed folate content and distribution in livers after 12 months on a choline-deficient diet. We found that this long-term deficiency did not significantly alter the total folate concentration in liver, however there was a significant difference between the control and deficient groups in the distribution of folate species. Whereas the major folates in the livers of control rats consisted of penta- and hexaglutamyl derivatives, those from the livers of the choline-deficient group were of longer chain lengths including hepta- and octaglutamyl derivatives. It is believed that chain elongation of the glutamate residues reflects, among other things, increased residence time of the folate molecule in the liver. A plausible interpretation of the previous and the present studies is that choline deprivation interferes with the assimilation of newly acquired folate by the hepatic tissue. Initially, during choline deprivation hepatic folate losses due to normal turnover were not promptly replenished, hence, we observed a decrease in folate level. However, when the period of choline deficiency was extended, impairment in the assimilation of folate was probably compensated for by minimizing folate losses by decreasing folate turnover rates. Hence, we observed an elongation of the glutamate ends of folate molecules.
Article
We investigated whether changes in apoptosis and cell proliferation induced by starvation and refeeding in rat liver may contribute to the initiation mechanism of liver cancer by 20 mg/kg of diethylnitrosamine (DENA). Rats were starved for 4 d, then refed and given 20 mg/kg of DENA after 1 d of refeeding. Rat livers were examined before and after DENA treatment to measure DNA loss and synthesis, the number of the placental form of glutathione S-transferase (P-GST) positive cells and their turnover. Four days of starvation depressed cell replication, as indicated by the labeling index (LI), and induced apoptosis, as shown by the decay of total DNA radioactivity and apoptotic index (AI, TUNEL technique). After 1 d of refeeding, AI significantly decreased and LI remained low, indicating that a high percentage of S phase cells was not required for the DNA damage due to 20 mg/kg of DENA. DENA induced apoptosis and the AI after 20 mg/kg of DENA was 3% in refed rats vs. 1% in fully-fed rats 5 d after DENA (P </= 0.05). Putative-initiated P-GST-positive hepatocytes appeared after administration of 20 mg/kg in refed rats, and they showed a higher LI (6%) than the surrounding P-GST-negative cells 3 d after DENA (LI = 2%; P </= 0.01), while very few P-GST-positive cells were found in fully-fed rats. These data indicate that starvation-induced cell loss and the subsequent refeeding trigger cell proliferation that gives a selective advantage to the cells initiated by 20 mg/kg of DENA to grow in the livers of refed rats.
Article
Impairments in folate-mediated 1-carbon metabolism are associated with several common diseases and developmental anomalies including intestinal cancers, vascular disease, cognitive decline, and neural tube defects. The etiology of folate-associated pathologies involves interactions among multiple genetic risk alleles and environmental factors, although the causal mechanisms that define the role of folate and other B-vitamins in these complex disorders remain to be established. Folate and other B-vitamins fundamentally differ from other nutrients that interact with the genome in determining health and disease outcomes in that their interaction is reciprocal. Common gene variants influence the activity of folate-dependent enzymes and anabolic pathways; folate-mediated 1-carbon metabolism is essential for the high-fidelity synthesis of DNA and activated methyl groups that are required for DNA methylation and regulation of chromatin structure. This review focuses on the regulation of folate-mediated 1-carbon metabolism and its role in maintaining genome integrity and on strategies for establishing the metabolic pathways and mechanisms that underlie folate-associated pathologies.
Article
Currently, cancer is recognized as a disease provoked by both genetic and epigenetic events. However, the significance of early genetic and epigenetic alterations with respect to carcinogenic process in general and to liver carcinogenesis in particular remains unexplored. A lack of knowledge regarding how specific alterations during early preneoplasia may be mechanistically related to tumor formation creates a major gap in understanding the role of these genetic and epigenetic abnormalities in carcinogenesis. In the present study we investigated the contribution of DNA damage and epigenetic alterations to liver carcinogenesis induced by a methyl-deficient diet. Feeding Fisher 344 rats a methyl-deficient diet for 9 weeks resulted in DNA damage and aberrant DNA methylation. This was evidenced by an early up-regulation of the base excision DNA repair genes, accumulation of 8-oxodeoxyguanosine and 3'OH-end strand breaks in DNA, pronounced global loss of DNA methylation, and hypermethylation of CpG islands in the livers of methyl-deficient rats. These abnormalities were completely restored in the livers of rats exposed to methyl-deficiency for 9 weeks after removal of the methyl-deficient diet and re-feeding a methyl-sufficient diet. However, when rats were fed a methyl-deficient diet for 18 week and then given a methyl-sufficient diet, only DNA lesions were repaired. The methyl-sufficient diet failed to restore completely the altered DNA methylation status and prevent the progression of liver carcinogenesis. These results suggest that stable alterations in DNA methylation are a factor that promotes the progression of liver carcinogenesis. Additionally, the results indicate that epigenetic changes may be more reliable markers than DNA lesions of the carcinogenic process and carcinogen exposure.
Article
Non-alcoholic fatty liver disease (NAFLD) is an increasingly reported pathology, characterized by fat accumulation within the hepatocyte. Growing evidences suggest specific effects on mitochondrial metabolism, but it is still unclear the relationship between fatty liver progression and mitochondrial function. In the present work we have investigated the impact of fatty liver on mitochondrial bioenergetic functions and susceptibility to mitochondrial permeability transition (MPT) induction in animals fed a choline-deficient diet (CDD) for 4, 8, 12 or 16 weeks. Mitochondria isolated from CDD animals always exhibited higher state 4 respiration. Mitochondrial membrane potential was decreased in CDD animals at 4 and 16 weeks. At 12 weeks, oxidative phosphorylation was more efficient in CDD animals, suggesting a possible early response trying to revert the deleterious effect of increased triglyceride storage in the liver. However, mitochondrial dysfunction was evident in CDD animals at 16 weeks as indicated by decreased RCR and ADP/O, with a corresponding decrease in respiratory chain enzymes activities. Such loss of respiratory efficiency was associated with accumulation of protein oxidation products, in tissue and mitochondrial fraction. Additionally, although no differences in ATPase activity, the lag phase was increased in mitochondria from CDD animals at 16 weeks, associated with decreased content of the adenine nucleotide translocator. Increased susceptibility to calcium-induced MPT was evident in CDD animals at all time points. These results suggest a dynamic mechanism for the development of NALFD associated with altered mitochondrial function.
Article
The fidelity of DNA synthesis is critically dependent on the correct balance and availability of the deoxynucleoside triphosphate (dNTP) precursors for the polymerases involved in replication and repair. Since folate-derived one-carbon groups are essential for the de novo synthesis of both purines and pyrimidines, the purpose of the present investigation was to determine whether diet-induced depletion of folates would alter intracellular dNTP pools. Fischer 344 rats were fed one of four semi-purified diets for a period of 8 weeks: (i) supplemented control; (ii) deficient in folic acid; (iii) deficient in methionine and choline; and (iv) deficient in methionine, choline and folic acid. In contrast to natural diets, semi-purified diets are nucleotide-free and consequently lack substrates for salvage pathway synthesis. This omission may place unusual stress on folate-dependent de novo nucleotide synthesis especially under conditions of dietary methyl-donor deficiency. Reversed-phase HPLC analysis of dNTP in spleen cell extracts indicated that both the thymidylate monophosphate and thymidylate triphosphate pools were decreased in spleen cells from the deficient rats consistent with a decrease in folate-dependent de novo synthesis. In addition, purine biosynthesis appeared to be negatively affect by methyl-donor deficiency as evidenced by a reduction in dGTP and dATP pools. These data indicate that deoxynucleotide pool imbalance, well known to produce cytogenetic and mutagenic events in vitro, can also be induced in this in vivo model of diet-induced carcinogenesis.
Article
Effects of dietary iron deficiency on inductions of putative preneoplastic lesions and oxidative alterations in the livers of rats by a choline-deficient L-amino acid defined (CDAA) diet were examined. Male Fischer 344 rats, 4 weeks old, were used with a total experimental period of 16 weeks, consisting of 4-week pretreatment and 12-week treatment periods (periods A and B respectively). During period A, a choline-supplemented L-amino acid defined (CSAA) or an iron-deficient CSAA diet was administered, and the CDAA or an iron-deficient CDAA diet was fed in period B. Formation of 8-hydroxydeoxyguanosine (8OHdG), a DNA adduct generated by activated oxygen species, in DNA and lipid peroxidation in liver cell membranes were sequentially determined after the beginning of period B. At the end of the experiment, development of gamma-glutamyltransferase (GGT) and glutathione S-transferase placental form (GSTP) positive liver lesions were quantitatively analysed. In the animals fed the CDAA diet, formation of 8OHdG and lipid peroxidation increased with time, and GGT and GSTP positive liver lesions developed. Formation of 8OHdG, lipid peroxidation and the numbers of induced enzyme-altered liver lesions were all reduced in rats fed the iron-deficient CSAA diet in period A and/or the iron-deficient CDAA diet in period B. The present results indicate that iron plays an important role in induction of preneoplastic liver lesions in rats caused by exposure to the CDAA diet possibly in connection with its known catalytic role in generation of highly reactive activated oxygen species.