Article

Inhibition of IKKɛ and TBK1 Improves Glucose Control in a Subset of Patients with Type 2 Diabetes

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

Abstract

Numerous studies indicate an inflammatory link between obesity and type 2 diabetes. The inflammatory kinases IKKɛ and TBK1 are elevated in obesity; their inhibition in obese mice reduces weight, insulin resistance, fatty liver and inflammation. Here we studied amlexanox, an inhibitor of IKKɛ and TBK1, in a proof-of-concept randomized, double-blind, placebo-controlled study of 42 obese patients with type 2 diabetes and nonalcoholic fatty liver disease. Treatment of patients with amlexanox produced a statistically significant reduction in Hemoglobin A1c and fructosamine. Interestingly, a subset of drug responders also exhibited improvements in insulin sensitivity and hepatic steatosis. This subgroup was characterized by a distinct inflammatory gene expression signature from biopsied subcutaneous fat at baseline. They also exhibited a unique pattern of gene expression changes in response to amlexanox, consistent with increased energy expenditure. Together, these data suggest that dual-specificity inhibitors of IKKɛ and TBK1 may be effective therapies for metabolic disease in an identifiable subset of patients.

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 authors.

... In addition, the therapeutic effect of AM on NAFLD also depended on the activation of M1. The content of activator protein-1 (AP-1) in subcutaneous fat of patients with obesity and type 2 diabetes was higher (Oral et al., 2017). AP-1 is a transcription regulatory factor of M1 and is involved in obesity-related adipose tissue inflammation. ...
... AP-1 is a transcription regulatory factor of M1 and is involved in obesity-related adipose tissue inflammation. AP-1 and inflammatory factors transcription were decreased following AM treatment, suggesting that AM reduced the M1/M2 ratio in adipose cells and inhibited the inflammatory response in adipose tissue (Oral et al., 2017). ...
... The expression of UCP1 in subcutaneous fat of patients with type 2 diabetes was increased, Frontiers in Pharmacology | www.frontiersin.org May 2022 | Volume 13 | Article 888588 and the β 3-adrenergic receptor ADRB3 gene was also highly expressed in the adipose tissue after treatment (Oral et al., 2017). It is worth noting that the hypoglycemic effect of AM seems to be more dependent on the inflammatory response of patients (Oral et al., 2017). ...
Article
Full-text available
IKKε (inhibitor of nuclear factor kappa-B kinase ε) is a member of the noncanonical NF-κB pathway. It participates in the inflammatory response and innate immunity against bacteria. In recent decades, IKKε has been closely associated with metabolic regulation. Inhibition of the IKKε pathway can improve fat deposition in the liver, reduce subcutaneous fat inflammation, and improve liver gluconeogenesis in obesity. IKKε is expected to be a new therapeutic target for metabolic diseases such as nonalcoholic fatty liver disease, diabetes, and obesity. Herein, we summarize the structural characterization, physiological function, and pathological role of IKKε in metabolic diseases and small molecule inhibitors of IKKε.
... In a proof-of-concept randomized, double-blinded clinical study, 42 obese and diabetic patients received placebo or amlexanox treatment for 12 weeks. Amlexanox significantly reduced hemoglobin A1c levels (101), indicating an improvement of glucose metabolism. Further study found that patients with higher serum C-reactive protein (CRP) levels and higher adipose tissue inflammation were more responsive to the drug. ...
... The expression of thermogenic genes, including Ucp1, Dio2 and Fgf21, was upregulated by the treatment as well in these patients. Within the responders, a transient increase of serum Interleukin 6 (IL-6) within 2-4 weeks of amlexanox treatment was reported (101). This observation is consistent with a previous mouse study showing that amlexanox upregulated Il6 expression and secretion via cAMP/Mitogenactivated protein kinase (MAPK) p38 pathway in inguinal white adipose tissue. ...
... Amlexanox, a drug with outstanding safety record, was identified as an inhibitor of TBK1 and IKKϵ. Thus far, multiple studies on both experimental mouse models and human subjects suggest its potential as a new treatment for metabolic diseases (37,101). ...
Article
Full-text available
Adipocytes and adipose tissue play critical roles in the regulation of metabolic homeostasis. In obesity and obesity-associated metabolic diseases, immune cells infiltrate into adipose tissues. Interaction between adipocytes and immune cells re-shapes both metabolic and immune properties of adipose tissue and dramatically changes metabolic set points. Both the expression and activity of the non-canonical IKK family member TBK1 are induced in adipose tissues during diet-induced obesity. TBK1 plays important roles in the regulation of both metabolism and inflammation in adipose tissue and thus affects glucose and energy metabolism. Here we review the regulation and functions of TBK1 and the molecular mechanisms by which TBK1 regulates both metabolism and inflammation in adipose tissue. Finally, we discuss the potential of a TBK1/IKKε inhibitor as a new therapy for metabolic diseases.
... Based on a double-blind randomized placebo-controlled study of 42 obese subjects, there were no serious significant adverse events [6] to 3 times daily oral amlexanox. In the study, two patients who experienced a perivascular inflammatory rash improved with local treatment and both had a favorable response to the drug. ...
... Oral et al (2017) [6] Double-blind, placebo study of 42 obese patients with type 2 diabetes and nonalcoholic fatty liver disease (NAFLD). Length: 12 weeks. ...
... The further analysis of drug responses of this patient population with co-morbid asthma is a subject of future investigation. Other findings among the treatment group included increased expression of the gene encoding the B3-adrenergic receptor (ADRB3) [6]. Takeuchi et al. hypothesize that the polymorphisms in ADRB3 receptor are associated with obesity and decreased lipolysis, which makes this finding notable [21]. ...
Article
Amlexanox, a small molecule targeted therapy which has been used in the treatment of atopic conditions was previously but is not currently available in the United States. Amlexanox has also been legally utilized and administered in Japan as a treatment for asthma, a chronic pulmonary disease characterized by inflammation of the lower respiratory tract. Amlexanox's immune modulatory effects have been the subject of studies which have repurposed the drug for potential therapeutic applications in metabolic and inflammatory disease. Because amlexanox inhibits TANK-binding kinase1 (TBK1) and nuclear factor kB kinase epsilon (IKKε), several studies have demonstrated its usefulness through its evidence downregulation of the immune system and attenuation of downstream TBK1 signaling. Novel therapies, such as amlexanox, for inflammatory conditions such as asthma will continue to be of value in clinical management. This report summarizes key applications of the drug based on animal and human studies and explores its potential in treatment of metabolic and inflammatory diseases.
... Beyond its well-known role in innate immunity, TBK1 has been implicated in oncogenesis and metabolic disorders linked to obesity such as type 2 diabetes, similar to mTOR and Akt (140,199,267,278,279,(282)(283)(284)(285)(286)295,296,(306)(307)(308)(309). In oncogenic KRas transformed cells, TBK1 promotes cell proliferation and survival and the growth of tumor explants in vivo, with either mTORC1 or Akt suggested as downstream mediators of TBK1 action (177,199,267,278,279,295,296,306,307). ...
... In diet-induced obese mice, adipocyte specific knockout of TBK1 decreases Akt S473 phosphorylation in white adipose tissue, increases insulin resistance and proinflammation, and impairs glucose homeostasis (285,310), a phenotype that overlaps with those resulting from adipocyte-specific knockout of Raptor (mTORC1) or Rictor (mTORC2) (138,140,141). Moreover, treatment of obese mice or human patients with amlexanox, or knockout of TBK1, Raptor (mTORC1 partner protein), or S6K1 (mTORC1 substrate) in mouse adipocytes, reduces adiposity and body mass, in part due to increased energy expenditure (285,(309)(310)(311). ...
Thesis
The mechanistic target of rapamycin (mTOR) senses diverse intracellular and extracellular cues to control key fundamental cellular processes, including cell growth and proliferation, cell survival, and metabolism. Consequently, aberrant mTOR activity contributes to various pathological diseases, including cancer, type 2 diabetes, and autoimmune diseases. mTOR nucleates the catalytic core of two multimeric complexes: mTOR complex 1 (mTORC1) and mTORC2. mTORC1 integrates nutrient and growth factor cues to promote cell growth, cell cycle progression, and anabolic processes, marked by increases in protein, lipid, and nucleotide biosynthesis. Growth factors and energetic stress activate mTORC2, which promotes cell survival and regulates metabolism. While upstream regulation of mTORC1, including the environmental stimuli and associated signaling intermediates, is far more comprehensively characterized, upstream regulation of mTORC2 remains woefully ill-defined. The noncanonical IKK-related kinases, Tank-binding kinase 1 (TBK1) and IKK epsilon (IKKe), initiate the innate immune response to circumvent pathogenic infection by integrating signals from various pattern recognition receptors’ detection of microbial-derived antigens. TBK1 and IKKe, in turn, phosphorylate and activate IRF-3/7 transcription factors to drive interferon beta (IFN-beta) production to promote eradication of infectious agents. Prior work from our lab identified TBK1 as a novel mTOR-S2159 kinase. In macrophages, TBK1-mediated phosphorylation of mTOR-S2159 within mTORC1 was found to promote IRF-3 nuclear translocation and IFN-beta production, and EGF-stimulated mTORC1 signaling was reduced in mouse embryonic fibroblasts (MEFs) lacking TBK1 or wild type MEFs treated with the TBK1 inhibitor amlexanox. While studying TBK1-mediated activation of mTORC1, we also observed reduced EGF-stimulated phosphorylation of Akt-S473, a well-established mTORC2 substrate. Here we demonstrate that TBK1-mediated phosphorylation of mTOR on S2159 increases mTORC2 intrinsic kinase activity and downstream signaling to Akt-S473 in response to EGF, and, more broadly, mTOR-S2159 phosphorylation promotes mTORC2 and mTORC1 signaling in response to a broader array of growth factors (EGF, FBS, PDGF, and insulin). Additionally, we demonstrate that mTOR-S2159 phosphorylation promotes TLR-3-mediated mTORC2 and mTORC1 signaling in response to the synthetic dsRNA mimetic, poly (I:C). Mechanistically, TBK1 interacts with mTORC2 in intact cells and phosphorylates mTOR-S2159 within mTORC2 in vitro. These results contribute important mechanistic insight toward our poor understanding of the upstream regulation of mTORC2. More importantly, since aberrant TBK1 and mTORC2 activity have both been implicated in pathological diseases, most notably obesity-driven type 2 diabetes and oncogenesis, the TBK1-mTORC2 axis may represent an attractive therapeutic target for such diseases.
... Amlexanox was used to treat asthma and conjunctivitis in Japan in the 1980s [199,200]. Amlexanox is an approved agent/drug for treating asthma and aphthous ulcers via inhibiting TBK1 [201]. The 2D representation of TBK1 structure with amlexanox showed that ligand binds to the ATP-binding position with a type I binding model (Fig. 5A). ...
... The prevention of TBK1 with WEHI-112 blocked inflammatory arthritis in antibody-dependent models [213]. However, a clinical trial study began with amlexanox in diabetes patients [199]. ...
Article
TANK-binding kinase 1 (TBK1) plays a fundamental role in regulating the cellular response to infecting pathogens and controlling several signaling cascades. It regulates inflammatory, interferon, NF-κB, autophagy, and Akt pathways. Post-translational modifications (PTM) of TBK1 strongly control its action and consequent cellular signaling. The dysregulation of the TBK1 pathway is correlated to many pathophysiological conditions, including cancer, that implicates the promising therapeutic advantage for targeting TBK1. The present study summarizes current information on the molecular mechanisms and cancer-inducing roles of TBK1. Designed inhibitors of TBK1 are considered a potential therapeutic agent for several diseases, including cancer. Data from pre-clinical tumor models recommend that the target of TBK1 can be a productive strategy and plan for anti-tumor therapy in particular settings. This review further highlighted the therapeutic potential of potent and selective TBK1 inhibitors, including Amlexanox, Compound II, BX795, MRT67307, SR8185 AZ13102909, CYT387, GSK8612, BAY985, and Domainex. These inhibitors may be implicated to facilitate therapeutic management of cancer and TBK1-associated diseases in the future.
... Beyond its well-known role in innate immunity, TBK1 has been implicated in oncogenesis and metabolic disorders linked to obesity such as type II diabetes, similar to mTOR and Akt (14)(15)(16)(17)28,(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54). In oncogenic KRas transformed cells, TBK1 promotes cell proliferation and survival and the growth of tumor explants in vivo, with either mTORC1 or Akt suggested as downstream mediators of TBK1 action (14)(15)(16)(17)(42)(43)(44)(45)(46). ...
... In diet-induced obese mice, adipocyte specific knockout of TBK1 decreases Akt S473 phosphorylation in white adipose tissue, increases whole-body insulin resistance and pro-inflammation, and impairs glucose homeostasis (50,54), a phenotype that overlaps with those resulting from adipocyte-specific knockout of Raptor (mTORC1) or Rictor (mTORC2) (28,(56)(57)(58). Moreover, treatment of obese mice or human patients with amlexanox, or knockout of TBK1, Raptor (mTORC1 partner protein), or S6K1 (mTORC1 substrate) in mouse adipocytes, reduces adiposity and body mass, in part due to increased energy expenditure (50,52,54,59). ...
Article
Full-text available
TBK1 responds to microbes to initiate cellular responses critical for host innate immune defense. We found previously that TBK1 phosphorylates mTOR (mechanistic target of rapamycin) on S2159 to increase mTOR complex 1 (mTORC1) signaling in response to the growth factor EGF and the viral dsRNA mimetic poly(I:C). mTORC1 and the less well studied mTORC2 respond to diverse cues to control cellular metabolism, proliferation, and survival. While TBK1 has been linked to Akt phosphorylation, a direct relationship between TBK1 and mTORC2, an Akt kinase, has not been described. By studying MEFs lacking TBK1, as well as MEFs, macrophages, and mice bearing an Mtor S2159A knock-in allele (MtorA/A) using in vitro kinase assays and cell-based approaches, we demonstrate here that TBK1 activates mTOR complex 2 (mTORC2) directly to increase Akt phosphorylation. We find that TBK1 and mTOR S2159 phosphorylation promote mTOR-dependent phosphorylation of Akt in response to several growth factors and poly(I:C). Mechanistically, TBK1 co-immunoprecipitates with mTORC2 and phosphorylates mTOR S2159 within mTORC2 in cells. Kinase assays demonstrate that TBK1 and mTOR S2159 phosphorylation increase mTORC2 intrinsic catalytic activity. Growth factors failed to activate TBK1 or increase mTOR S2159 phosphorylation in MEFs. Thus, basal TBK1 activity cooperates with growth factors in parallel to increase mTORC2 (and mTORC1) signaling. Collectively, these results reveal crosstalk between TBK1 and mTOR, key regulatory nodes within two major signaling networks. As TBK1 and mTOR contribute to tumorigenesis and metabolic disorders, these kinases may work together in a direct manner in a variety of physiological and pathological settings.
... Moreover, the side effects of systemic TBK1 inhibition within-trial are relevant for assessing TBK1 as a possible therapeutic target to cancer patients. Since there were no severe adverse effects identified [146]. Therefore, mild to moderate effects included two rash incidents that decided to carry on amlexanox treatment [114]. ...
... The inhibitors of TBK1 have been proposed and used in various cell-based studies and animal models, but no clinical trials started for cancer [144,147,148]. Louis et al. [149] observed; the inhibition of TBK1 with WEHI-112 inhibited inflammatory arthritis within antibody-dependent models. Therefore, a clinical trial was started with amlexanox in diabetes patients, and results observed got better glucose to regulate in the treated patients [146]. ...
Article
TANK-binding kinase 1 (TBK1) regulates various biological processes including, NF-κB signaling, immune response, autophagy, cell division, Ras-mediated oncogenesis, and AKT pro-survival signaling. Enhanced TBK1 activity is associated with autoimmune diseases and cancer, suggesting its role in therapeutic targeting of interferonopathies. In addition, dysregulation of TBK1 activity promotes several inflammatory disorders and oncogenesis. Structural and biochemical study reports provide the molecular process of TBK1 activation and recap the substrate selection about TBK1. This review summarizes recent findings on the molecular mechanisms by which TBK1 is involved in cancer signaling. The IKK-ε and TBK1 are together associated with inflammatory diseases by inducing type I IFNs. Furthermore, TBK1 signaling regulates radiation-induced epithelial-mesenchymal transition by controlling phosphorylation of GSK-3β and expression of Zinc finger E-box-binding homeobox 1, suggesting, TBK1 could be targeted for radiotherapy-induced metastasis therapy. Despite a considerable increase in the list of TBK1 inhibitors, only a few have the potential to control cancer. Among them, a compound BX795 is considered a potent and selective inhibitor of TBK1. We discussed the therapeutic potential of small-molecule inhibitors of TBK1, particularly those with high selectivity, which will enable further exploration in the therapeutic management of cancer and inflammatory diseases.
... Beyond its well-known role in innate immunity, TBK1 has been implicated in oncogenesis and metabolic disorders linked to obesity such as type II diabetes, similar to mTOR and Akt (14)(15)(16)(17)28,(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54). In oncogenic KRas transformed cells, TBK1 promotes cell proliferation and survival and the growth of tumor explants in vivo, with either mTORC1 or Akt suggested as downstream mediators of TBK1 action (14)(15)(16)(17)(42)(43)(44)(45)(46). ...
... In diet-induced obese mice, adipocyte specific knockout of TBK1 decreases Akt S473 phosphorylation in white adipose tissue, increases insulin resistance and pro-inflammation, and impairs glucose homeostasis (50,54), a phenotype that overlaps with those resulting from adipocyte-specific knockout of Raptor (mTORC1) or Rictor (mTORC2) (28, [56][57][58]. Moreover, treatment of obese mice or human patients with amlexanox, or knockout of TBK1, Raptor (mTORC1 partner protein), or S6K1 (mTORC1 substrate) in mouse adipocytes, reduces adiposity and body mass, in part due to increased energy expenditure (50,52,54,59). ...
Preprint
TBK1 (TANK-binding kinase 1) responds to microbial pathogens to initiate cellular responses critical for host innate immune defense. We found previously that TBK1 phosphorylates mTOR (mechanistic target of rapamycin) (on S2159) to increase mTOR complex 1 (mTORC1) activity and signaling in response to the growth factor EGF and the viral dsRNA mimetic poly(I:C). mTORC1 and the less well studied mTORC2 respond to diverse cues to control cellular metabolism, proliferation, and survival. Here we demonstrate that TBK1 activates mTOR complex 2 (mTORC2) directly to increase Akt phosphorylation at physiological levels of protein expression. We find that TBK1 phosphorylates mTOR S2159 within mTORC2 in vitro , phosphorylates mTOR S2159 in cells, and interacts with mTORC2 in cells. By studying MEFs lacking TBK1, as well as MEFs, macrophages, and mice bearing an Mtor S2159A knock-in allele ( Mtor A/A ), we show that TBK1 and mTOR S2159 phosphorylation increase mTORC2 catalytic activity and promote mTOR-dependent downstream signaling to Akt in response to several growth factors and poly(I:C). While microbial-derived stimuli activate TBK1, we find that growth factors fail to activate TBK1 or increase mTOR S2159 phosphorylation in MEFs. Thus, we propose that basal TBK1 activity cooperates with growth factors in parallel to increase mTORC2 (and mTORC1) signaling. Collectively, these results reveal crosstalk between TBK1 and mTOR complexes (mTORCs), key nodes within two major signaling systems. As TBK1 and mTORCs have each been linked to tumorigenesis and metabolic disorders, these kinases may work together in a direct manner in a variety of physiological and pathological settings. One Sentence Summary The innate immune kinase TBK1 directly activates mTORC2
... Recent analysis of STING protein sequences, however, demonstrated that the IFN signalingrelated function of this protein, that is mediated by its C-terminal tail (CTT), is a relatively recent addition, and that its conserved role is the induction of cellular autophagy in response to cytosolic dsDNA [10]. Furthermore, the identification of crosstalk between mammalian target of rapamycin complex 1 (mTORC1) signaling and the cGAS-STING pathway uncovered a crucial role for this signaling axis in insulin resistance, type 2 diabetes, and non-alcoholic fatty liver disease (NAFLD) [11][12][13][14]. Even the role of dsDNA as a sole activator of STING has been challenged by studies reporting that viral particle fusion with the plasma membrane is sufficient to promote STING-dependent IFN signaling in a dsDNA-and cGAS-independent manner [15,16]. ...
... TBK1 is known to attenuate noncanonical NF-κB through phosphorylation and degradation of NF-κB-inducing kinase (NIK) ( Figure 3A). In separate studies, however, pharmacological inhibition of the downstream effector TBK1/IKKε by amlexanox or knockout of IRF3 improved glucose tolerance, reduced body weight, and enhanced insulin sensitivity [12,14,56]. Taken together, ...
Article
The cyclic GMP-AMP synthase (cGAS)–stimulator of interferon genes (STING) pathway has been primarily characterized as an inflammatory mechanism in higher eukaryotes in response to cytosolic double-stranded DNA (dsDNA). Since its initial discovery, detailed mechanisms delineating the dynamic subcellular localization of its different components and downstream signaling have been uncovered, leading to attempts to harness its proinflammatory properties for therapeutic benefit in cancer. Emerging evidence, however, indicates that a crucial primordial function of STING is to promote autophagy, and that downstream interferon (IFN) signaling emerged recently in its evolutionary history. Furthermore, studies suggest that this pathway is a crucial regulator of cellular metabolism that potentially couples inflammation to nutrient availability. We focus on the evolutionarily conserved functions of STING, and we discuss how a broader understanding of this pathway can help us to better appreciate its potential role in cancer and harness it for therapeutic benefit.
... Obesity-induced chronic inflammation increases the production of proinflammatory cytokines, such as TNFα, in adipose tissue, and these cytokines stimulate NF-κB activity in adipocytes and induce TBK1 and IKKε expression [13][14][15][16] . Recent clinical studies have also shown that IKKε/TBK1 inhibitor can improve hepatic steatosis and insulin sensitivity in obese patients with non-alcoholic fatty liver disease (NAFLD) and T2D 17 . Activated TBK1 can phosphorylate AMPKα directly 15 . ...
... In addition, mice lacking IKKε also display improvements in insulin sensitivity and glucose and lipid homeostasis, as well as reductions in the activation of chronic inflammation pathways 18 . Using dual-specificity inhibitors of IKKε and TBK1 can increase energy consumption and insulin sensitivity by inducing fat cell browning and enhancing catecholamine sensitivity 13,17 . The activation of IKKε and TBK1 can reduce energy consumption and increase energy storage and insulin resistance. ...
Article
Full-text available
Berberine (BBR) exerts specific therapeutic effects on various diseases such as diabetes, obesity, and other inflammation-associated diseases. However, the low oral bioavailability (below 1%) of berberine due to its poor solubility and membrane permeability limits its clinical use. In this paper, we have prepared a 1:1 co-crystal berberine-ibuprofen (BJ) using drug salt metathesis and co-crystal technology. Pharmacokinetic studies demonstrate a 3-fold increase in vivo bioavailability of BJ compared to that of BBR, and BJ is more effective in treating obesity and its related metabolism in vitro and in vivo. We also find that BJ promotes mitochondrial biogenesis by inhibiting TBK1 and inducing AMP‐activated protein kinase (AMPK) phosphorylation, and BJ increases adipocyte sensitivity to catecholamine by inhibiting IKKε. Together, our findings support that co-crystal BJ is likely to be an effective agent for treating obesity and its related metabolic diseases targeting TBK1 and IKKε. The co-crystal berberine-ibuprofen is an effective agent for treating obesity through a reduction of the activity of the non-canonical I κB kinases, IKKε and TBK1.
... Obese mice display elevated levels of IKKε in the liver, adipocytes and ATM, while IKKε deficiency protects against diet-induced obesity, chronic inflammation, hepatic steatosis and insulin resistance [96]. Treatment of obese diabetic patients with an inhibitor of IKKε can improve blood glucose levels and increase energy expenditure [97]. Additionally, suppressor of cytokine signaling (SOCS) proteins, which are upregulated during inflammation, induce proteolytic degradation of IRS proteins, thereby contributing to insulin resistance [98][99][100]. ...
... Reduction of hyperglycemia restrains monocytosis in obese mice [344]. Moreover, treatment of obese diabetic patients with an inhibitor of IKKε and TBK1 (amlexanox) reduces to some extent inflammatory gene expression in the subcutaneous adipose tissue and ameliorates insulin sensitivity and hepatic steatosis [97]. Furthermore, anakinra (a recombinant human IL-1 receptor antagonist) was found to mitigate systemic inflammation in type 2 diabetes mellitus patients [351,352]. ...
Article
Full-text available
Metabolic disorders, such as obesity, type 2 diabetes mellitus, and nonalcoholic fatty liver disease, are characterized by chronic low-grade tissue and systemic inflammation. During obesity, the adipose tissue undergoes immunometabolic and functional transformation. Adipose tissue inflammation is driven by innate and adaptive immune cells and instigates insulin resistance. Here, we discuss the role of innate immune cells, that is, macrophages, neutrophils, eosinophils, natural killer cells, innate lymphoid type 2 cells, dendritic cells, and mast cells, in the adipose tissue in the healthy (lean) and diseased (obese) state and describe how their function is shaped by the obesogenic microenvironment, and humoral, paracrine, and cellular interactions. Moreover, we particularly outline the role of hypoxia as a central regulator in adipose tissue inflammation. Finally, we discuss the long-lasting effects of adipose tissue inflammation and its potential reversibility through drugs, caloric restriction, or exercise training.
... TBK1 (TANK binding kinase 1), a non-canonical IKK-related innate immune kinase, responds to microbial-derived signals to initiate host defense responses against viral and bacterial pathogens (1; 2). More recent work implicates TBK1 in energy storage, improved glycemic control, suppression of pro-inflammatory responses, and tumorigenesis, revealing TBK1 as a multi-functional kinase (3)(4)(5)(6)(7)(8)(9)(10). The conserved kinase mTOR (mechanistic target of rapamycin) functions as a metabolic rheostat by integrating multiple environmental cues to control fundamental cellular functions important for diverse physiological processes (11)(12)(13)(14). ...
... These mice also display improved insulin sensitivity and glycemic control, likely due in part to decreased obesity (3). Clinically, amlexanox also reduces body weight and improves glycemic control in obese patients (4), revealing TBK1 and IKK as potential new therapeutic targets for the treatment of obesity. Similar to system-wide inhibition of TBK1/ IKK with amlexanox (3), global reduction of TBK1 kinase activity in DIO mice due to expression of truncated TBK1 alleles (Tbk1  ) (6) reduces body weight and adiposity with consequent improvements in glycemic control, insulin sensitivity, and inflammatory state (6). ...
Article
The innate immune kinase TBK1 (TANK-binding kinase 1) responds to microbial-derived signals to initiate responses against viral and bacterial pathogens. More recent work implicates TBK1 in metabolism and tumorigenesis. The kinase mTOR (mechanistic target of rapamycin) integrates diverse environmental cues to control fundamental cellular processes. Our prior work demonstrated in cells that TBK1 phosphorylates mTOR (on S2159) to increase mTORC1 and mTORC2 catalytic activity and signaling. Here we investigate a role for TBK1-mTOR signaling in control of glucose metabolism in vivo. We find that diet induced obese (DIO) but not lean mice bearing a whole-body “TBK1 resistant” Mtor S2159A knockin allele (MtorA/A) display exacerbated hyperglycemia and systemic insulin resistance with no change in energy balance. Mechanistically, Mtor S2159A knockin in DIO mice reduces mTORC1 and mTORC2 signaling in response to insulin and innate immune agonists, reduces anti-inflammatory gene expression in adipose tissue, and blunts anti-inflammatory macrophage M2 polarization, phenotypes shared by mice with tissue-specific inactivation of TBK1 or mTOR complexes. Tissues from DIO mice display elevated TBK1 activity and mTOR S2159 phosphorylation relative to lean mice. We propose a model whereby obesity-associated signals increase TBK1 activity and mTOR phosphorylation, which boosts mTORC1 and mTORC2 signaling in parallel to the insulin pathway, thereby attenuating insulin resistance to improve glycemic control during diet-induced obesity.
... In HFD-induced obesity, STING downstream kinase TBK1 activation dysregulated energy homeostasis by directly inhibiting the central energy homeostasis regulator AMPK at Thr142 of the AMPKa subunit 176 . While inhibition of TBK1, IRF3, and IKKε improved glucose tolerance, insulin sensitivity, energy expenditure, and decreased body weight in type two diabetes patients and adipocytes 176,177 . However, surprisingly, TBK1 shows to have bidirectional activity on inflammatory pathways in adipocytes 44,176 . ...
Article
Full-text available
The cyclic GMP–AMP synthase (cGAS)–stimulator of interferon genes (STING) signaling exert essential regulatory function in microbial-and onco-immunology through the induction of cytokines, primarily type I interferons. Recently, the aberrant and deranged signaling of the cGAS–STING axis is closely implicated in multiple sterile inflammatory diseases, including heart failure, myocardial infarction, cardiac hypertrophy, nonalcoholic fatty liver diseases, aortic aneurysm and dissection, obesity, etc. This is because of the massive loads of damage-associated molecular patterns (mitochondrial DNA, DNA in extracellular vesicles) liberated from recurrent injury to metabolic cellular organelles and tissues. Interestingly, the cGAS–STING pathway crosstalk with essential intracellular homeostasis processes like apoptosis, autophagy and also regulate cellular metabolism. Targeting derailed STING signaling has become necessary for chronic inflammatory diseases. Meanwhile, excessive type I interferons signaling impact on cardiovascular and metabolic health remain entirely elusive. In this review, we summarize the intimate connection between the cGAS–STING pathway and cardiovascular and metabolic disorders. We also discuss some potential small molecule inhibitors for the pathway. Importantly, this review will provide insight to stimulate interest in and support future research into understanding this signaling axis in cardiovascular and metabolic tissues and diseases.
... 316,317 Consistently, pharmacological inhibition of TBK1 enhances insulin sensitivity and reduces chronic inflammation caused by obesity. 316,318,319 However, the potential bidirectional roles of TBK1 in regulating inflammation should not be ignored, as it is found to promote STING ubiquitination and degradation and in turn elevate NF-κB activity and inflammation. 320 Nevertheless, the crosstalk between TBK1 in the STING pathway and inflammation status and insulin resistance merits further investigation. ...
Article
Full-text available
Obesity is a complex, chronic disease and global public health challenge. Characterized by excessive fat accumulation in the body, obesity sharply increases the risk of several diseases, such as type 2 diabetes, cardiovascular disease, and nonalcoholic fatty liver disease, and is linked to lower life expectancy. Although lifestyle intervention (diet and exercise) has remarkable effects on weight management, achieving long-term success at weight loss is extremely challenging, and the prevalence of obesity continues to rise worldwide. Over the past decades, the pathophysiology of obesity has been extensively investigated, and an increasing number of signal transduction pathways have been implicated in obesity, making it possible to fight obesity in a more effective and precise way. In this review, we summarize recent advances in the pathogenesis of obesity from both experimental and clinical studies, focusing on signaling pathways and their roles in the regulation of food intake, glucose homeostasis, adipogenesis, thermogenesis, and chronic inflammation. We also discuss the current anti-obesity drugs, as well as weight loss compounds in clinical trials, that target these signals. The evolving knowledge of signaling transduction may shed light on the future direction of obesity research, as we move into a new era of precision medicine.
... inhibitor CYT387 or amlexanox, a more specific TBK1 inhibitor (Reilly et al. 2013;Oral et al. 2017). We found that both KPC and iKras*p53* PDAC cell lines expressed active, In iKras*p53* cells, amlexanox administration induced an increase in TBK1 phosphorylation as well. ...
Thesis
Pancreatic cancer is the fourth leading cause of malignancy-related mortality in the United States. Despite decades of intensive research, patient 5-year survival following diagnosis remains below 10%. The high mortality rate can be attributed to lack of effective therapies, and pancreatic cancer resistance to traditional cancer treatment modalities. The goal of this study was to identify molecular mechanisms of pancreatic cancer resistance to treatment and ideally characterize novel drug targets, which may prove efficacious in combating this devastating disease. To achieve this, we optimized a 3D culture model system that utilized Matrigel as a basement membrane mimetic, facilitating cell-to-cell adhesion as well as cell-to-extracellular-matrix interactions, similar to tumor signaling dynamics in vivo. In this cell culture system, pancreatic cancer cells recapitulated oncogene addiction and other in vivo characteristics of disease. We chose to study the molecular mechanism of MAPK blockade in this 3D culture system and found that pancreatic cancer cells relied on β1 integrin signaling to mediate resistance in the context of MAPK blockade. Furthermore, β1 integrin signaling was found to be necessary for upregulation of MAPK signaling in the absence of extracellular matrix signaling. These findings reveal a novel role for β1 integrin in pancreatic cancer pathogenesis and give insight into the molecular mechanisms that drive disease.
... Insulin sensitivity and regulation of glucose levels were also improved due to activation of the hepatic JAK/STAT pathway by IL-6 whose expression is regulated by cAMP levels in adipocytes (Reilly et al., 2015). Given the history of safety using amlexanox (Bell, 2005), phase I and II clinical trials in obese and diabetic patients were conducted at the University of Michigan Medical Center in which a subset of patients was identified for their positive response to amlexanox treatment (Oral et al., 2017). Patients showed improvements in glycated hemoglobin (HbA1C), insulin sensitivity, and displayed a reduction in hepatic steatosis while exhibiting changes in energy expenditure gene expression similar to those previously noted in animal studies. ...
Thesis
Adrenergic receptors (AR) are G protein-coupled receptors (GPCRs) responsible for regulating physiological processes including the fight-or-flight response, muscle contraction, blood flow, and energy release. Numerous protein kinases play key roles in AR signaling cascades such as GPCR kinases (GRKs) and inflammatory kinases whose aberrant activity contributes to cardiovascular disease, hypertension, type 2 diabetes, and obesity. Thus, a detailed molecular understanding of the structure, function, and regulation of these kinases will therefore facilitate the development of novel therapeutic interventions. Obesity results in chronic inflammation of adipocytes through increased expression of inflammatory kinases, namely, IKKe and TBK1, which indirectly attenuate B3 adrenergic receptor signaling to decrease energy expenditure and disrupt glucose homeostasis. Together, excessive activity of IKKε and TBK1 exacerbates the obese phenotype and leads to the development of type 2 diabetes. The drug amlexanox is a modest potency inhibitor of both kinases that produces weight loss and improves insulin sensitivity when administered to obese mice. Herein, I report the co-crystal structure of TBK1 in complex with amlexanox and a comprehensive profiling of the structure-activity relationships (SAR) of amlexanox analogs. Through the determination of seven co-crystal structures of TBK1 in complex with amlexanox and amlexanox analogs inhibitors, we uncovered mechanisms for improving potency, cellular efficacy, and selectivity against IKKe and TBK1. Future efforts on targeting IKKe and TBK1 should carefully consider pharmacokinetics, as we observe a stark disconnect between in vitro potency and efficacy in cells and animals. Taken together, amlexanox undoubtedly represents a pharmacophore amenable to therapeutic development whose analogs may have clinical value in the treatment of diabetes and obesity. Heart contractility is carefully regulated through the activation of the a1 adrenergic receptor and subsequent desensitization by GRKs. Excessive activation of a1AR, such as during cardiac arrest, leads to abnormally high levels of intracellular Ca2+ and activation of calmodulin (Ca2+CaM) which inhibits GRK5 and promotes nuclear translocation of the kinase, leading to maladaptive ventricular hypertrophy. I determined the architecture of the Ca2+CaM–GRK5 complex through small X-ray scattering and electron microscopy, which show that Ca2+CaM inhibits GRK5 via bitopic bridging to two different regions of GRK5. The natural product calmodulin inhibitor malbrancheamide, which I showed binds exclusively to the C-terminal lobe of Ca2+CaM in a co-crystal structure, was used to probe the Ca2+CaM–GRK5 interaction. I establish malbrancheamide as a tool for probing the regulatory effects of half the Ca2+CaM interaction. The bitopic nature of Ca2+CaM binding to GRK5 produces different modes of regulation which may therefore be exploited for therapeutic development. In particular, disrupting the C-terminal interaction may retain GRK5 at the cell membrane and block cardiac hypertrophy. Together, my work suggests that natural products may serve as useful probes for studying Ca2+CaM protein-protein interactions. Future efforts should consider the utility of screening natural product compound libraries to identify additional molecules that may be of use in studying maladaptive cardiac pathologies.
... Inhibition of inflammatory kinases (IKKɛ and TBK1) has been studied in mice, and the results showed a reduction in weight, insulin resistance, steatohepatitis, and inflammation. Amlexanox, which is a dual kinase inhibitor, was shown to reduce HbA 1c and steatohepatitis in T2DM patients [107]. βcell dysfunction in T2DM is a result of inflammation. ...
Article
Full-text available
Introduction Diabetes mellitus is a serious metabolic disorder that is associated with high morbidity and mortality, and that affects people worldwide – especially in Asia. Genetics plays an important role in disease development, prevention, and therapeutic approach. Precision medicine in diabetes requires a profound understanding of both genetics and the plethora of mechanisms of diabetes. Areas covered This review comprehensively describes and discusses the recent advances in genetics-based prediction, diagnosis, prevention, and treatment of diabetes, and the potential impact of these advances on precision medicine, especially in the Asian population. We analyzed the available literature from the PubMed Central® (PMC) archive. Expert opinion Advanced genetic knowledge can lead to the precise diagnosis, improved risk prediction, diabetes prevention, and genetics-based diabetes treatment. Increased understanding, availability, and affordability of genetics-based strategies will improve the quality of life of those with and those at risk for developing diabetes.
... Furthermore, AMX-induced inhibition of Tbk1 has been linked to the decrease in phosphorylation of IRF3 and IRF7 (Mori et al., 2015;Quan et al., 2019;Zhou et al., 2020), implying the downregulation of Tbk1-mediated Interferon signaling. AMX was originally approved for human use in dermatological conditions (Abbasi et al., 2016), and, because of its effects on reducing NF-kB and IRF3/7 activation (through the double targeting of Tbk1 and IKK-ε) AMX has been proposed as a therapeutic agent in autoimmune neuroinflammatory disorders (Quan et al., 2019), neoplastic progression (Wilcz-Villega et al., 2020) and diabetesassociated macrophage-driven inflammation (Oral et al., 2017). ...
Article
Full-text available
Traumatic brain injury has a poorer prognosis in elderly patients, possibly because of the enhanced inflammatory response characteristic of advanced age, known as “inflammaging.” Recently, reduced activation of the TANK-Binding-Kinase 1 (Tbk1) pathway has been linked to age-associated neurodegeneration and neuroinflammation. Here we investigated how the blockade of Tbk1 and of the closely related IKK-ε by the small molecule Amlexanox could modify the microglial and immune response to cortical stab-wound injury in mice. We demonstrated that Tbk1/IKK-ε inhibition resulted in a massive expansion of microglial cells characterized by the TMEM119+/CD11c+ phenotype, expressing high levels of CD68 and CD317, and with the upregulation of Cst7a, Prgn and Ccl4 and the decrease in the expression levels of Tmem119 itself and P2yr12, thus a profile close to Disease-Associated Microglia (DAM, a subset of reactive microglia abundant in Alzheimer’s Disease and other neurodegenerative conditions). Furthermore, Tbk1/IKK-ε inhibition increased the infiltration of CD3+ lymphocytes, CD169+ macrophages and CD11c+/CD169+ cells. The enhanced immune response was associated with increased expression of Il-33, Ifn-g, Il-17, and Il-19. This upsurge in the response to the stab wound was associated with the expanded astroglial scars and increased deposition of chondroitin-sulfate proteoglycans at 7 days post injury. Thus, Tbk1/IKK-ε blockade results in a massive expansion of microglial cells with a phenotype resembling DAM and with the substantial enhancement of neuroinflammatory responses. In this context, the induction of DAM is associated with a detrimental outcome such as larger injury-related glial scars. Thus, the Tbk1/IKK-ε pathway is critical to repress neuroinflammation upon stab-wound injury and Tbk1/IKK-ε inhibitors may provide an innovative approach to investigate the consequences of DAM induction.
... Human studies and animal models suggested that adipose tissue dysfunction contributes to the metabolic dysregulation associated with obesity (Bi et al., 2014;Hajer et al., 2008), hepatic insulin resistance (Mottillo et al., 2016;Tang et al., 2016), and diabetes (Hajer et al., 2008;Yang et al., 2005). Although the molecular events underlying the relationship between adipose dysfunction and these system metabolism abnormalities remain uncertain, recent studies have implicated inflammation is a potentially unifying cause (Hajer et al., 2008;Hotamisligil, 2017;Oral et al., 2017). Indeed, several studies revealed that the NF-κB transcriptional program activation is linked to the inflammatory response in adipocytes (Hajer et al., 2008;Zhao et al., 2018). ...
Article
Full-text available
White adipose tissues (WAT) play crucial roles in maintaining whole-body energy homeostasis, and their dysfunction can contribute to hepatic insulin resistance and type 2 diabetes mellitus (T2DM). However, the mechanisms underlying these alterations remain unknown. By analyzing the transcriptome landscape in human adipocytes based on available RNA-seq datasets from lean, obese, and T2DM patients, we reveal elevated mitochondrial reactive oxygen species (ROS) pathway and NF-κB signaling with altered fatty acid metabolism in T2DM adipocytes. Mice with adipose-specific deletion of mitochondrial redox Trx2 develop hyperglycemia, hepatic insulin resistance, and hepatic steatosis. Trx2-deficient WAT exhibited excessive mitophagy, increased inflammation, and lipolysis. Mechanistically, mitophagy was induced through increasing ROS generation and NF-κB–dependent accumulation of autophagy receptor p62/SQSTM1, which recruits damaged mitochondria with polyubiquitin chains. Importantly, administration of ROS scavenger or NF-κB inhibitor ameliorates glucose and lipid metabolic disorders and T2DM progression in mice. Taken together, this study reveals a previously unrecognized mechanism linking mitophagy-mediated adipose inflammation to T2DM with hepatic insulin resistance.
... 17,18 Amlexanox is also effective for the treatment of obesity and type 2 diabetes. 19,20 Moreover, the potential potency of inhibition in GBM cell lines was recently demonstrated. 21 As far as we know, more and more research studies are being conducted to study the effect of combined therapy on GBM. 4 Cold atmospheric plasma technology, a novel technique investigated as a stand-alone treatment on the tumor in vivo and in vitro, was demonstrated to amply cytotoxicity of TMZ by combining it with TMZ. ...
Article
Full-text available
Temozolomide (TMZ), as the first-line chemotherapeutic agent for the treatment of glioblastoma multiforme (GBM), often fails to improve the prognosis of GBM patients due to the quick development of resistance. The need for more effective management of GBM is urgent. The aim of this study is to evaluate the efficacy of combined therapy with TMZ and amlexanox, a selective inhibitor of IKBKE, for GBM. We found that the combined treatment resulted in significant induction of cellular apoptosis and the inhibition of cell viability, migration, and invasion in primary glioma cells and in the human glioma cell line, U87 MG. As expected, TMZ enhanced the expression of p-AMPK and amlexanox led to the reduction of IKBKE, with no impact on p-AMPK. Furthermore, we demonstrated that compared to other groups treated with each component alone, TMZ combined with amlexanox effectively reversed the TMZ-induced activation of Akt and inhibited the phosphorylation of mTOR. In addition, the combination treatment also clearly reduced in vivo tumor volume and prolonged median survival time in the xenograft mouse model. These results suggest that amlexanox sensitized the primary glioma cells and U87 MG cells to TMZ at least partially through the suppression of IKBKE activation and the attenuation of TMZ-induced Akt activation. Overall, combined treatment with TMZ and amlexanox may provide a promising possibility for improving the prognosis of glioblastoma patients in clinical practice.
... In diet-induced obese (DIO) AT, pro-inflammatory macrophages accumulate and the production of pro-inflammatory cytokines such as interleukin-6 (IL-6) and tumor necrosis factor TNF is elevated, which suppresses insulin sensitivity in the AT [4,5]. Furthermore, blockage of inflammatory macrophage recruitment and activation by means of genetic manipulation or pharmacological treatment has been demonstrated to improve obesity-associated AT inflammation and insulin resistance [6][7][8][9]. These observations demonstrate that AT inflammation is a potential target for nutritional intervention, to prevent and treat obesity-induced metabolic syndrome. ...
Article
Fatty acid esters of hydroxyl fatty acids (FAHFAs) are a new family of endogenous lipids that exert anti-inflammatory action. Among the various FAHFA isomers, the dietary source of oleic acid-hydroxy stearic acid (OAHSA) and its anti-inflammatory functions are poorly understood. This study investigated the composition of OAHSA isomers in dietary oils and the impact of 12-OAHSA on obesity-induced inflammation. LC-MS/MS analysis revealed that various dietary oils, including fish oil, corn oil, palm oil, soybean oil, and olive oil, present a wide variation in OAHSA profiles and amounts. The highest amounts of total OAHSAs are present in olive oil including 12-OAHSA. Compared to vehicle-treated obese mice, administration of 12-OAHSA significantly improved glucose homeostasis, independent of body weight. 12-OAHSA-treated mice displayed significantly reduced accumulation of CD11c⁺ adipose tissue macrophages, and CD4⁺/CD8⁺ adipose tissue T lymphocytes. Concomitantly, the expression of pro-inflammatory cytokine genes and the NF-κB signaling pathway were significantly decreased in the 12-OAHSA-treated adipose tissue, while the expression of the anti-inflammatory gene Il10 was markedly increased. Moreover, in vitro cell culture experiments showed that 12-OAHSA significantly inhibited the LPS-induced inflammatory response in macrophages by suppressing the NF-κB signaling pathway. Collectively, these results indicated that 12-OAHSA, as a component of olive oil, mitigates obesity-induced insulin resistance by regulating AT inflammation. Therefore, 12-OAHSA could be used as a novel nutritional intervention against obesity-associated metabolic dysregulation.
... White visceral adipose tissue (VAT) dysfunction plays a central role, bolstering local and systemic inflammation and insulin resistance [4] . Studies demonstrate anti-inflammatory treatments in obese individuals decrease the risk of cardiovascular disease and other comorbidities [5][6][7][8] ; however, targeted approaches to decrease inflammation are necessary to limit deleterious effects. ...
Article
Obesity is a prevalent health risk by inducing chronic, low-grade inflammation and insulin resistance, in part from adipose tissue inflammation perpetuated by activated B cells and other resident immune cells. However, regulatory mechanisms controlling B-cell actions in adipose tissue remain poorly understood, limiting therapeutic innovations. MicroRNAs are potent regulators of immune cell dynamics through fine-tuning a network of downstream genes in multiple signaling pathways. In particular, miR-150 is crucial to B-cell development and suppresses obesity-associated inflammation via regulating adipose tissue B-cell function. Herein, we review the effect of microRNAs on B-cell development, activation, and function and highlight miR-150-regulated B-cell actions during obesity which modulate systemic inflammation and insulin resistance. In this way, we hope to promote translational discoveries that mitigate obesity-induced health risks by targeting microRNA-regulated B-cell actions.
... There are several TBK1 inhibitors that have been described in the literature (Table 1), although only amlexanox is FDAapproved (aphthous ulcers) and only momelotinib has undergone early phase clinical testing for cancer. Amlexanox has been shown to improve glucose control in patients with diabetes and was generally well tolerated [190], but has not been evaluated in patients with malignancy. Newer more selective TBK1 inhibitors, as well as TBK1 PROTACs, are still in preclinical development, and currently there are no clinical trials evaluating TBK1 inhibitors that are enrolling patients (clinicaltrials.gov), ...
Article
Introduction: TANK-binding kinase 1 (TBK1) is a Ser/Thr kinase with a central role in coordinating the cellular response to invading pathogens and regulating key inflammatory signaling cascades. While intact TBK1 signaling is required for successful anti-viral signaling, dysregulated TBK1 signaling has been linked to a variety of pathophysiologic conditions, including cancer. Several lines of evidence support a role for TBK1 in cancer pathogenesis, but the specific roles and regulation of TBK1 remain incompletely understood. A key challenge is the diversity of cellular processes that are regulated by TBK1, including inflammation, cell cycle, autophagy, energy homeostasis, and cell death. Nevertheless, evidence from pre-clinical cancer models suggest that targeting TBK1 may be an effective strategy for anti-cancer therapy in specific settings. Areas covered: This review provides an overview of the roles and regulation of TBK1 with a focus on cancer pathogenesis and drug targeting of TBK1 as an anti-cancer strategy. Relevant literature was derived from a PubMed search encompassing studies from 1999 to 2020. Expert opinion: TBK1 is emerging as a potential target for anti-cancer therapy. Inhibition of TBK1 alone may be insufficient to restrain the growth of most cancers, hence combination strategies will likely be necessary. Improved understanding of tumor-intrinsic and tumor-extrinsic TBK1 signaling will inform novel therapeutic strategies.
... White adipose tissue (WAT) dysfunction plays a central role through two primary contributing aspects: low-degree chronic inflammation and insulin resistance, as well as other health risk factors such as hyperlipidemia and hypertension [4]. Studies have demonstrated that controlling obesity-associated WAT inflammation can improve tissue function and systemic health outcomes [5][6][7][8][9]. Given the significance of WAT expansion and its pathogenic role in obesity, we will focus on summarizing the current knowledge of microRNA-regulated adipose tissue macrophage (ATM) actions that impact WAT function in this review. ...
Article
Full-text available
Obesity-induced adipose tissue dysfunction is bolstered by chronic, low-grade inflammation and impairs systemic metabolic health. Adipose tissue macrophages (ATMs) perpetuate local inflammation but are crucial to adipose tissue homeostasis, exerting heterogeneous, niche-specific functions. Diversified macrophage actions are shaped through finely regulated factors, including microRNAs, which post-transcriptionally alter macrophage activation. Numerous studies have highlighted microRNAs’ importance to immune function and potential as inflammation-modulatory. This review summarizes current knowledge of regulatory networks governed by microRNAs in ATMs in white adipose tissue under obesity stress.
... Some patients in both trials displayed rashes diagnosed as perivascular inflammation, a pathology similar to the inflammatory skin lesions seen in Tbk1 ∆/∆ mice, suggesting an on-target side effect of TBK1 inhibition [187,279]. While these studies demonstrated that oral AMX is safe, well-tolerated, and effective in ameliorating metabolic abnormalities, the efficacy of AMX as an antineoplastic agent is unknown but warrants clinical investigation [247,280]. MMB has been evaluated for the treatment of metastatic PDA, EGFR-or K-RAS-activated NSCLC (Table 3) [18,[261][262][263][264][265][266][267]; however, oral MMB at doses of 100-300 mg QID did not show any clinically meaningful benefit, neither as monotherapy nor in combination with other drugs. The pharmacodynamics studies indicated that even with average maximal plasma concentrations of ~ 300 ng/mL, TBK1 was not inhibited to any therapeutically-significant extent [18,262,[264][265][266][267]. ...
Article
Full-text available
The TANK-binding kinase 1 (TBK1) is a serine/threonine kinase belonging to the non-canonical inhibitor of nuclear factor-κB (IκB) kinase (IKK) family. TBK1 can be activated by pathogen-associated molecular patterns (PAMPs), inflammatory cytokines, and oncogenic kinases, including activated K-RAS/N-RAS mutants. TBK1 primarily mediates IRF3/7 activation and NF-κB signaling to regulate inflammatory cytokine production and the activation of innate immunity. TBK1 is also involved in the regulation of several other cellular activities, including autophagy, mitochondrial metabolism, and cellular proliferation. Although TBK1 mutations have not been reported in human cancers, aberrant TBK1 activation has been implicated in the oncogenesis of several types of cancer, including leukemia and solid tumors with KRAS -activating mutations. As such, TBK1 has been proposed to be a feasible target for pharmacological treatment of these types of cancer. Studies suggest that TBK1 inhibition suppresses cancer development not only by directly suppressing the proliferation and survival of cancer cells but also by activating antitumor T-cell immunity. Several small molecule inhibitors of TBK1 have been identified and interrogated. However, to this point, only momelotinib (MMB)/CYT387 has been evaluated as a cancer therapy in clinical trials, while amlexanox (AMX) has been evaluated clinically for treatment of type II diabetes, nonalcoholic fatty liver disease, and obesity. In this review, we summarize advances in research into TBK1 signaling pathways and regulation, as well as recent studies on TBK1 in cancer pathogenesis. We also discuss the potential molecular mechanisms of targeting TBK1 for cancer treatment. We hope that our effort can help to stimulate the development of novel strategies for targeting TBK1 signaling in future approaches to cancer therapy.
... Moreover, expression of TBK1 and IKKε is induced upon a high-fat diet (HFD) in metabolic tissues to control glucose and energy homeostasis [33][34][35] . Pharmacological inhibition of TBK1/IKKε promoted energy expenditure in adipose tissue with attenuated hepatic steatosis and improved insulin sensitivity in mouse models of obesity, and enhanced glucose control in a subset of patients with type 2 diabetes (T2D) and non-alcoholic fatty liver disease (NAFLD) 33,36 . Intriguingly, TBK1 and IKKε distinctively control glucose and energy metabolism in response to a HFD. ...
Article
Full-text available
Small-molecule inhibitors of non-canonical IκB kinases TANK-binding kinase 1 (TBK1) and IκB kinase ε (IKKε) have shown to stimulate β-cell regeneration in multiple species. Here we demonstrate that TBK1 is predominantly expressed in β-cells in mammalian islets. Proteomic and transcriptome analyses revealed that genetic silencing of TBK1 increased expression of proteins and genes essential for cell proliferation in INS-1 832/13 rat β-cells. Conversely, TBK1 overexpression decreased sensitivity of β-cells to the elevation of cyclic AMP (cAMP) levels and reduced proliferation of β-cells in a manner dependent on the activity of cAMP-hydrolyzing phosphodiesterase 3 (PDE3). While the mitogenic effect of (E)3-(3-phenylbenzo[c]isoxazol-5-yl)acrylic acid (PIAA) is derived from inhibition of TBK1, PIAA augmented glucose-stimulated insulin secretion (GSIS) and expression of β-cell differentiation and proliferation markers in human embryonic stem cell (hESC)-derived β-cells and human islets. TBK1 expression was increased in β-cells upon diabetogenic insults, including in human type 2 diabetic islets. PIAA enhanced expression of cell cycle control molecules and β-cell differentiation markers upon diabetogenic challenges, and accelerated restoration of functional β-cells in streptozotocin (STZ)-induced diabetic mice. Altogether, these data suggest the critical function of TBK1 as a β-cell autonomous replication barrier and present PIAA as a valid therapeutic strategy augmenting functional β-cells.
... Recently, scientists have reported repurposed calcium channel blockers in the management of gestational diabetes (Goldstein et al., 2018). Similarly, another study reported an antiasthmatic drug as a repurposing drug that benefits diabetes mellitus (Oral et al., 2017). ...
Article
In recent years, the drug repositioning strategy has gained considerable attention in the drug discovery process that involves establishing new therapeutic uses of already known drugs. In line with this, we have identified digoxin a cardiac glycoside, as a potent inhibitor of soluble epoxide hydrolase (sEH) enzyme employing in silico high throughput screening protocols and further confirmed using in vitro cell‐free sEH inhibitory assay and in vivo preclinical studies in rodents for its repurposing in hyperalgesia, inflammation, and related disorders. Oral administration of digoxin at dose 0.2 mg/kg significantly reduced (p < .0001) the allodynia in mice induced by using hot plate (3.6 ± 1.9) and tail‐flick test (7.58 ± 0.9). In addition, digoxin at a dose of 0.2 mg/kg showed marked reduction (94%, p < .0001) in acetic acid‐induced abdominal contraction in rats. Further, digoxin also demonstrated antipyretic activity (37.04 ± 0.2, p < .0001) and showed notable reduction (0.60 ± 0.06) in carrageenan‐induced paw edema in rats. Also, the histopathological evaluation revealed that digoxin treatment attenuated the edema, neutrophil infiltration, and alveolar septal thickening in lung tissue. These findings are novel and highlight the newer insights towards repurposing digoxin as a new lead in the treatment of hyperalgesia, inflammation, and related disorders.
... However, the exact mechanisms including regulation of HDACs by inflammatory conditions and specific HDACs involved are not completely clarified yet. Furthermore, the impact of the noncanonical IκB Kinase epsilon which has been repeatedly associated with inflammatory processes and inflammatory diseases [16][17][18] is not known in this context so far. Current evidence suggests that class I HDACs are the main players in innate immunity by regulation of inflammatory reactions while class II HDACs are mostly involved in mechanisms of adaptive immunity [10]. ...
Article
Full-text available
Class I and II histone deacetylases (HDAC) are considered important regulators of immunity and inflammation. Modulation of HDAC expression and activity is associated with altered inflammatory responses but reports are controversial and the specific impact of single HDACs is not clear. We examined class I and II HDACs in TLR-4 signaling pathways in murine macrophages with a focus on IκB kinase epsilon (IKKε) which has not been investigated in this context before. Therefore, we applied the pan-HDAC inhibitors (HDACi) trichostatin A (TSA) and suberoylanilide hydroxamic acid (SAHA) as well as HDAC-specific siRNA. Administration of HDACi reduced HDAC activity and decreased expression of IKKε although its acetylation was increased. Other pro-inflammatory genes (IL-1β, iNOS, TNFα) also decreased while COX-2 expression increased. HDAC 2, 3 and 4, respectively, might be involved in IKKε and iNOS downregulation with potential participation of NF-κB transcription factor inhibition. Suppression of HDAC 1–3, activation of NF-κB and RNA stabilization mechanisms might contribute to increased COX-2 expression. In conclusion, our results indicate that TSA and SAHA exert a number of histone- and HDAC-independent functions. Furthermore, the data show that different HDAC enzymes fulfill different functions in macrophages and might lead to both pro- and anti-inflammatory effects which have to be considered in therapeutic approaches.
... However, TBK1 is also involved in the pathogenesis of autoimmune diseases (Louis et al., 2018). TBK1 inhibitors such as amlexanox have been used in clinical treatment for asthma (Inagaki et al., 1992) and have recently been proposed for the treatment of obesity-related metabolic disease (Reilly et al., 2013;Oral et al., 2017). Our findings suggest that TBK1 inhibitors should be administered with caution, considering their possible effect on humoral immunity in case of infection and vaccination. ...
Article
Full-text available
The germinal center (GC) is a site where somatic hypermutation and clonal selection are coupled for antibody affinity maturation against infections. However, how GCs are formed and regulated is incompletely understood. Here, we identified an unexpected role of Tank-binding kinase-1 (TBK1) as a crucial B cell–intrinsic factor for GC formation. Using immunization and malaria infection models, we show that TBK1-deficient B cells failed to form GC despite normal Tfh cell differentiation, although some malaria-infected B cell–specific TBK1-deficient mice could survive by GC-independent mechanisms. Mechanistically, TBK1 phosphorylation elevates in B cells during GC differentiation and regulates the balance of IRF4/BCL6 expression by limiting CD40 and BCR activation through noncanonical NF-κB and AKTT308 signaling. In the absence of TBK1, CD40 and BCR signaling synergistically enhanced IRF4 expression in Pre-GC, leading to BCL6 suppression, and therefore failed to form GCs. As a result, memory B cells generated from TBK1-deficient B cells fail to confer sterile immunity upon reinfection, suggesting that TBK1 determines B cell fate to promote long-lasting humoral immunity.
Article
Hepatic TANK (TRAF family member associated NFκB activator)-binding kinase 1 (TBK1) activity is increased during obesity, and administration of a TBK1 inhibitor reduces fatty liver. Surprisingly, liver-specific TBK1 knockout in mice produces fatty liver by reducing fatty acid oxidation. TBK1 functions as a scaffolding protein to localize acyl-CoA synthetase long-chain family member 1 (ACSL1) to mitochondria, which generates acyl-CoAs that are channeled for β-oxidation. TBK1 is induced during fasting and maintained in the unphosphorylated, inactive state, enabling its high affinity binding to ACSL1 in mitochondria. In TBK1-deficient liver, ACSL1 is shifted to the endoplasmic reticulum to promote fatty acid re-esterification in lieu of oxidation in response to fasting, which accelerates hepatic lipid accumulation. The impaired fatty acid oxidation in TBK1-deficient hepatocytes is rescued by the expression of kinase-dead TBK1. Thus, TBK1 operates as a rheostat to direct the fate of fatty acids in hepatocytes, supporting oxidation when inactive during fasting and promoting re-esterification when activated during obesity.
Article
Multicomponent reactions (MCRs) are important processes, in which more than three different reactants directly get converted into one new structure bearing most of the atoms of these reactants. It is a very powerful tool in drug discovery and combinational chemistry. A new pseudo‐four‐component synthetic approach to 5‐(5‐hydroxy‐3‐methyl‐1H‐pyrazol‐4‐yl)‐substituted 5H‐chromeno[2,3‐b]pyridines with 68‐95% yields is reported. This multicomponent reaction opens an efficient and convenient way to substituted 5H‐chromeno[2,3‐b]pyridines, which are promising compounds in medicinal chemistry and for the treatment of lung cancer through inhibition of aldo‐keto reductase 1B10. New consensus approach of molecular docking and molecular dynamics were applied for the investigation of interaction of synthesized 5H‐chromeno[2,3‐b]pyridines and aldo‐keto reductase 1B10.
Article
The IKK family is most well studied in the context of control of inflammatory gene expression, particularly in the regulation of NF-κB and IRF transcription factors. While the major targets of IKK in regulation of NF-κB and IRF signaling have been extensively studied, IKK family members are now known to phosphorylate proteins not related to NF-κB- or IRF-dependent transcription mechanisms. Recently, a variety of novel IKK family-dependent phosphorylation events have been described. This aspect of IKK function, in our opinion, is currently underappreciated and is critical for understanding the biology of these kinases and understanding effects of IKK family-directed inhibitors. The nuances of these regulatory mechanisms are especially important since aberrant regulation of IKK family kinases has been implicated in a wide range of human diseases, including cancer, obesity, diabetes, heart disease, and pathogen infection. The inhibitor of kappa B kinase (IKK) family consists of IKKα, IKKβ, and the IKK-related kinases TBK1 and IKKε. These kinases are considered master regulators of inflammation and innate immunity via their control of the transcription factors NF-κB, IRF3, and IRF7. Novel phosphorylated substrates have been attributed to these kinases, a subset of which is not directly related to either inflammation or innate immunity. These findings have greatly expanded the perspectives on the biological activities of these kinases. In this review we highlight some of the novel substrates for this kinase family and discuss the biological implications of these phosphorylation events.
Chapter
It has become increasingly evident that the diversity of adipose tissue types may play distinct and potentially important roles in human physiology. White adipose tissue (WAT), the primary energy storage tissue, is important in homeostasis but when found in excess can predispose individuals to severe insulin resistance and diabetes. Human life is compatible with WAT composing between 4 and 60% of total body mass, pointing to its incredible adaptability. In contrast, brown adipose tissue (BAT), typically thought to occur only in hibernating animals and babies, is becoming recognized for its role in human energy expenditure, hormone production, immune regulation, among others. BAT usually comprises around 0–2% of total body mass; however, recent scientific advances in noninvasive imaging and molecular biology have allowed to explore unknown functions of this dynamic tissue. We discuss here the anatomy and physiology of WAT and BAT in the lean and obese human, and potential mechanisms regarding the interplay within obesity and Type 2 diabetes. Later, we review the current methodology for measuring and detecting WAT and BAT, how to experimentally modulate BAT activity, as well as future investigations to yield greater insight into BAT’s functional role in human health.
Chapter
The RAL proteins RALA and RALB belong to the superfamily of small RAS-like GTPases (guanosine triphosphatases). RAL GTPases function as molecular switches in cells by cycling through GDP- and GTP-bound states, a process which is regulated by several guanine exchange factors (GEFs) and two heterodimeric GTPase activating proteins (GAPs). Since their discovery in the 1980s, RALA and RALB have been established to exert isoform-specific functions in central cellular processes such as exocytosis, endocytosis, actin organization and gene expression. Consequently, it is not surprising that an increasing number of physiological functions are discovered to be controlled by RAL, including neuronal plasticity, immune response, and glucose and lipid homeostasis. The critical importance of RAL GTPases for oncogenic RAS-driven cellular transformation and tumorigenesis still attracts most research interest. Here, RAL proteins are key drivers of cell migration, metastasis, anchorage-independent proliferation, and survival. This chapter provides an overview of normal and pathological functions of RAL GTPases and summarizes the current knowledge on the involvement of RAL in human disease as well as current therapeutic targeting strategies. In particular, molecular mechanisms that specifically control RAL activity and RAL effector usage in different scenarios are outlined, putting a spotlight on the complexity of the RAL GTPase signaling network and the emerging theme of RAS-independent regulation and relevance of RAL.
Article
A formal [3 + 3] cascade annulation strategy for the synthesis of 2‐arylchromeno[2,3‐ b ]pyridinones has been developed using 2‐aminochromones and substituted cinnamaldehydes or aromatic aldehydes and ethanal as the substrates. The strategy supplies a novel and atom‐economical method of accessing a broad range of chromeno[2,3‐ b ]pyridine derivatives in good yields with good functional‐group tolerance. The method highlights the inherent practicality of this synthetic transformation.
Article
The protein kinases IKK-epsilon and TBK1 are activated in liver and fat in mouse models of obesity. We have previously demonstrated that treatment with the IKK-epsilon/TBK1 inhibitor, amlexanox, produces weight loss and relieves insulin resistance in obese animals and patients. While amlexanox treatment caused a transient reduction in food intake, long-term weight loss was attributable to increased energy expenditure via FGF21-dependent beiging of WAT. Amlexanox increased FGF21 synthesis and secretion in several tissues. Interestingly, while hepatic secretion determined circulating levels, it was dispensable for regulating energy expenditure. In contrast, adipocyte-secreted FGF21 may have acted as an autocrine factor that leads to adipose tissue browning and weight loss in obese mice. Moreover, increased energy expenditure was an important determinant of improved insulin sensitivity by amlexanox. Conversely, the immediate reductions in fasting blood glucose observed with acute amlexanox treatment were mediated by suppression of hepatic glucose production via the activation of STAT3 by adipocyte-secreted IL-6. These findings demonstrate that amlexanox improved metabolic health via FGF21 action in adipocytes to increase energy expenditure via WAT beiging, and an endocrine role of adipocyte-derived IL-6 to decrease gluconeogenesis via hepatic STAT3 activation, thereby producing a coordinated improvement in metabolic parameters.
Article
Our purpose was to study the effect of hyperglycemia on macrophage TBK1-HIF-1α-mediated IL-17/IL-10 signaling and its correlation with coronary atherosclerosis. A total of 135 patients with coronary heart disease (CHD) were divided into a stable CHD (SCHD) group (n = 30) and an acute myocardial infarction (AMI) group (n = 105) [nondiabetes mellitus (non-DM)-AMI, n = 60; DM-AMI, n = 45] from January to September 2020. The SYNTAX score and metabolic and inflammatory markers were quantified and compared. THP-1 cell studies and an animal study of coronary intimal hyperplasia were also carried out. We found that the DM-AMI group showed a higher SYNTAX score than the non-DM-AMI group (P < .05). The DM-AMI group showed the highest expression levels of TANK-binding kinase 1 (TBK1), hypoxia-inducible factor 1α (HIF-1α), and interleukin (IL)-17 and the lowest expression level of IL-10, followed by the non-DM-AMI group and the SCHD group (P < .05). THP-1 cell studies showed that BAY87-2243 (a HIF-1α inhibitor) reversed the increase in IL-17 and decrease in IL-10 expression induced by hyperglycemia. Amlexanox (a TBK1 inhibitor) reversed the increase in HIF-1α expression induced by hyperglycemia. Amlexanox treatment resulted in lower coronary artery intimal hyperplasia and a larger lumen area in a diabetic swine model. We conclude that hyperglycemia might aggravate the complexity of coronary atherosclerosis through activation of TBK1-HIF-1α-mediated IL-17/IL-10 signaling. Thus, TBK1 may be a novel drug therapy target for CHD complicated with DM.
Article
The prevalence of heart failure is on the rise and imposes a major health threat, in part, due to the rapidly increased prevalence of overweight and obesity. To this point, epidemiological, clinical and experimental evidence supports the existence of a unique disease entity termed "obesity cardiomyopathy", which develops independent of hypertension, coronary heart disease and other heart diseases. Our contemporary review evaluates the evidence for this pathological condition, examines putative responsible mechanisms, and discusses therapeutic options for this disorder. Clinical findings have consolidated the presence of left ventricular dysfunction in obesity. Experimental investigations have uncovered pathophysiological changes in myocardial structure and function in genetically-predisposed and diet-induced obesity. Indeed, contemporary evidence consolidates a wide array of cellular and molecular mechanisms underlying the etiology of obesity cardiomyopathy including adipose tissue dysfunction, systemic inflammation, metabolic disturbances (insulin resistance, abnormal glucose transport, spillover of free fatty acids, lipotoxicity, and amino acid derangement), altered intracellular especially mitochondrial Ca2+ homeostasis, oxidative stress, autophagy/mitophagy defect, myocardial fibrosis, dampened coronary flow reserve, coronary microvascular disease (microangiopathy), and endothelial impairment. Given the important role of obesity in the increased risk of heart failure, especially that with preserved systolic function and the recent rises in COVID-19-associated cardiovascular mortality, this review should provide compelling evidence for the presence of obesity cardiomyopathy, independent of various comorbid conditions, underlying mechanisms, and offer new insights into potential therapeutic approaches (pharmacological and lifestyle modification) for the clinical management of obesity cardiomyopathy.
Article
Dysregulation of TANK-binding kinase 1 (TBK1) homeostasis leads to the occurrence and progression of many diseases, such as inflammation, autoimmune diseases, metabolic diseases, and cancer. Therefore, there is a need to develop TBK1 inhibitors as therapeutic agents. In this review, we highlight the diverse biological functions of TBK1 and summarize the promising small-molecule inhibitors of TBK1 that have the potential to be developed as therapeutic candidates.
Article
Full-text available
Type 2 diabetes is a metabolic, chronic disorder characterized by insulin resistance and elevated blood glucose levels. Although a large drug portfolio exists to keep the blood glucose levels under control, these medications are not without side effects. More importantly, once diagnosed diabetes is rarely reversible. Dysfunctions in the kidney, retina, cardiovascular system, neurons, and liver represent the common complications of diabetes, which again lack effective therapies that can reverse organ injury. Overall, the molecular mechanisms of how type 2 diabetes develops and leads to irreparable organ damage remain elusive. This review particularly focuses on novel targets that may play role in pathogenesis of type 2 diabetes. Further research on these targets may eventually pave the way to novel therapies for the treatment—or even the prevention—of type 2 diabetes along with its complications. Type 2 diabetes is a complex metabolic disorder associated with a plethora of complications in peripheral organs. This review article highlights the novel targets that might play role in pathogenesis of type 2 diabetes. Further research on these targets might eventually pave the way to novel therapies for the treatment–or even the prevention–of type 2 diabetes.
Article
Purpose Nonalcoholic fatty liver disease (NAFLD), more recently referred to as metabolic-associated fatty liver disease, refers to a disease spectrum ranging from hepatic steatosis to nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis, associated with hepatic complications (including liver fibrosis, cirrhosis, and hepatocellular carcinoma) and extrahepatic complications (particularly cardiometabolic complications, including type 2 diabetes and cardiovascular disease). Treatment options include lifestyle interventions (dietary modification and physical activity programs) and pharmacologic interventions. Treatment aims should be broad, with a hepatic focus (to improve/reverse hepatic inflammation, fibrosis, and steatohepatitis), ideally with additional extrahepatic effects affecting metabolic co-morbidities (eg, insulin resistance, glucose dysregulation, dyslipidemia), causing weight loss and affording cardiovascular protection. NASH and fibrosis represent the main histopathological features that warrant treatment to prevent disease progression. Despite a paucity of established treatments, the array of potential molecular targets, pathways, and potential treatments is continually evolving. The goal of this article was to provide a narrative review summarizing the emerging and more established therapeutic options considering the complex pathophysiology of NAFLD and the important long-term sequelae of this condition. Methods The literature was reviewed by using PubMed, conference abstracts, and press releases from early-phase clinical studies to provide an overview of the evidence. Findings As understanding of the pathophysiology of NASH/NAFLD evolves, drugs with different mechanisms of action, targeting different molecular targets and aberrant pathways that mediate hepatic steatosis, inflammation, and fibrosis, have been developed and are being tested in clinical trials. Pharmacologic therapies fall into 4 main categories according to the molecular targets/pathways they disrupt: (1) meta-bolic targets, targeting insulin resistance, hepatic de novo lipogenesis, or substrate utilization; (2) inflam-matory pathways, inhibiting inflammatory cell recruitment/signaling, reduce oxidative/endoplasmic reticulum stress or are antiapoptotic; (3) the liver–gut axis, which modulates bile acid enterohepatic circulation/signaling or alters gut microbiota; and (4) antifibrotic targets, targeting hepatic stellate cells, decrease collagen deposition or increase fibrinolysis. Implications Lifestyle modification must remain the cornerstone of treatment. Pharmacologic treatment is reserved for NASH or fibrosis, the presence of which requires histopathological confirmation. The disease complexity provides a strong rationale for combination therapies targeting multiple pathways simultaneously.
Article
Objectives Beta-3 adrenergic receptors (β3-AR) stimulate lipolysis and thermogenesis in white and brown adipose tissue (WAT and BAT). Obesity increases oxidative stress and inflammation that attenuate AT β3-AR signaling. The objective of this study was to test the hypothesis that the combination of the β3-AR agonist CL-316,243 (CL) and the antioxidant alpha-lipoic acid (ALA) would lower inflammation in diet-induced obesity (DIO) and improve β3-AR function. Methods A total of 40 DIO mice were separated into four groups: Control (per os and intraperitoneal [IP] vehicle); CL alone (0.01 mg/kg IP daily); ALA alone (250 mg/kg in drinking water); or ALA+CL combination, all for 5 weeks. Results Food intake was similar in all groups; however, mice receiving ALA+CL showed improved body composition and inflammation as well as lower body weight (+1.7 g Control vs. −2.5 g ALA+CL [−7%]; p < 0.01) and percentage of body fat (−9%, p < 0.001). Systemic and epididymal WAT inflammation was lower with ALA+CL than all other groups, with enhanced recruitment of epididymal WAT anti-inflammatory CD206+ M2 macrophages. β3-AR signaling in WAT was enhanced in the combination-treatment group, with higher mRNA and protein levels of thermogenic uncoupling protein 1 and AT lipases. Conclusions Chronic treatment with ALA and a β3-AR agonist reduces DIO-induced inflammation. AT immune modulation could be a therapeutic target in patients with obesity.
Article
Amlexanox, an anti‐inflammatory and anti‐allergic agent, has been widely used clinically for the treatment of canker sores, asthma, and allergic rhinitis. Recently, amlexanox has received considerable attention in curing nonalcoholic fatty liver diseases and hepatitis virus infection. Herein, we first established a sensitive high‐performance liquid chromatography‐tandem mass spectrum (LC‐MS/MS) method for the determination of amlexanox in rat plasma. Propranolol was used as the internal standard (IS). Using a simple protein precipitation method, the amlexanox and IS were separated with Capcell Pak C18 column (2.0 × 50 mm, 5 μm) and eluted with water and acetonitrile each containing 0.1% formic acid using gradient elution condition at a flow rate of 0.4 mL·min‐1. Amlexanox and IS were detected by a triple quadrupole mass in multiple reactive monitoring (MRM) under the transitions of m/z 299.2 → 281.2 and m/z 259.9→116.1 with positive electrospray ionization, respectively. The calibration curves of amlexanox were established with the range of 50 to 2000 ng·mL‐1 (r2 > 0.99). The validation method consisted of selectivity, accuracy, precision, carryover effect, matrix effect, recovery, dilution effect, and stability. The fully validated method was successfully applied to the pharmacokinetic study of amlexanox in Wistar rats.
Article
Amlexanox (AMX) is an azoxanthone drug used for decades for the treatment of mouth aphthous ulcers and now considered for the treatment of diabetes and obesity. The drug is usually viewed as a dual inhibitor of the non-canonical IκB kinases IKK-ɛ (inhibitor-kappaB kinase epsilon) and TBK1 (TANK-binding kinase 1). But a detailed target profile analysis indicated that AMX binds directly to twelve protein targets, including different enzymes (IKK-ɛ, TBK1, GRK1, GRK5, PDE4B, 5- and 12-lipoxygenases) and non-enzyme proteins (FGF-1, HSP90, S100A4, S100A12, S100A13). AMX has been demonstrated to have marked anticancer effects in multiple models of xenografted tumors in mice, including breast, colon, lung and gastric cancers and in onco-hematological models. The anticancer potency is generally modest but largely enhanced upon combination with cytotoxic (temozolide, docetaxel), targeted (selumetinib) or biotherapeutic agents (anti-PD-1 and anti-CTLA4 antibodies). The multiple targets participate in the anticancer effects, chiefly IKK-ɛ/TBK1 but also S100A proteins and PDE4B. The review presents the molecular basis of the antitumor effects of AMX. The capacity of the drug to block nonsense-mediated mRNA decay (NMD) is also discussed, as well as AMX-induced reduction of cancer-related pain. Altogether, the analysis provides a survey of the anticancer action of AMX, with the implicated protein targets. The use of this well-tolerated drug to treat cancer should be further considered and the design of newer analogues encouraged.
Article
Cardiovascular diseases, especially atherosclerosis and its complications, are a leading cause of death. Inhibition of the non-canonical IκB kinases TBK1 and IKKε with amlexanox restores insulin sensitivity and glucose homeostasis in diabetic mice and human subjects. Here we report that amlexanox improves diet-induced hypertriglyceridemia and hypercholesterolemia in Western diet (WD)-fed Ldlr-/- mice, and protects against atherogenesis. Amlexanox ameliorates dyslipidemia, inflammation and vascular dysfunction through synergistic actions that involve upregulation of bile acid synthesis to increase cholesterol excretion. Transcriptomic profiling demonstrates an elevated expression of key bile acid synthesis genes. Furthermore, we found that amlexanox attenuates monocytosis, eosinophilia and vascular dysfunction during WD-induced atherosclerosis. These findings demonstrate the potential of amlexanox as a new therapy for hypercholesterolemia and atherosclerosis.
Article
A pseudo-three-component annulation reaction of substituted 2-amino-4H-chromen-4-ones with aromatic aldehydes promoted by DBU was investigated to access polysubstituted 5H-chromeno[2,3-b]pyridines. This reaction included a sequential intermolecular nucleophilic addition/Michael cyclization/intramolecular epoxidation/ring opening/aromatization sequence, which possessed excellent step and atom economy in a single operation for generating 3-hydroxy-5H-chromeno[2,3-b]pyridines from readily available substrates.
Article
Obesity and cancer cachexia are diseases at opposite ends of the BMI. However, despite the apparent dichotomy, these pathologies share some common underlying mechanisms that lead to profound metabolic perturbations. Insulin resistance, adipose tissue lipolysis, skeletal muscle atrophy and systemic inflammation are key players in both diseases. Several strategies for pharmacological treatments have been employed in obesity and cancer cachexia but demonstrated only limited effects. Therefore, there is still a need to develop novel, more effective strategies. In this review we summarize existing therapies and discuss potential novel strategies that could arise by bridging common aspects between obesity and cachexia. We discuss the potential role of macrophage manipulation and the modulation of inflammation by targeting Nuclear Receptors (NRs) as potential novel therapeutic strategies.
Article
Full-text available
Context: Partial lipodystrophy (PL) is associated with metabolic co-morbidities but may go undiagnosed as the disease spectrum is not fully described. Objective: Define disease spectrum in PL using genetic, clinical (historical, morphometric) and laboratory characteristics. Design: Cross-sectional evaluation. Participants: 23 patients (22 with familial, one acquired, 78.3% female, aged 12-64 years) with PL and non-alcoholic fatty liver disease (NAFLD). Measurements: Genetic, clinical and laboratory characteristics, body composition indices, liver fat content by MRI, histopathological and immunofluorescence examinations of liver biopsies. Results: 7 patients displayed heterozygous pathogenic variants in LMNA. Two related patients had a heterozygous, likely pathogenic novel variant of POLD1 (NM002691.3: c.3199 G>A; p.E1067K). Most patients had high ratios (>1.5) of %fat trunk to %fat legs (FMR) when compared to reference normals. Liver fat quantified using MR Dixon method was high (11.3+6.3%) and correlated positively with hemoglobin A1c and triglycerides while leg fat by dual-energy X-ray absorptiometry (DEXA) correlated negatively with triglycerides. In addition to known metabolic comorbidities; chronic pain (78.3%), hypertension (56.5%) and mood disorders (52.2%) were highly prevalent. Mean NAFLD Activity Score (NAS) score was 5±1 and 78.3% had fibrosis. LMNA-immunofluorescence staining from select patients (including one with the novel POLD1 variant) showed a high degree of nuclear atypia and disorganization. Conclusions: PL is a complex multi-system disorder. Metabolic parameters correlate negatively with extremity fat and positively with liver fat. DEXA-based FMR may prove useful as a diagnostic tool. Nuclear disorganization and atypia may be a common biomarker even in the absence of pathogenic variants in LMNA. This article is protected by copyright. All rights reserved.
Article
Full-text available
Despite considerable progress in identifying causal genes for lipodystrophy syndromes, the molecular basis of some peculiar adipose tissue disorders remains obscure. In an Israeli–Arab pedigree with a novel autosomal recessive, multiple symmetric lipomatosis (MSL), partial lipodystrophy and myopathy, we conducted exome sequencing of two affected siblings to identify the disease-causing mutation. The 41-year-old female proband and her 36-year-old brother reported marked accumulation of subcutaneous fat in the face, neck, axillae, and trunk but loss of subcutaneous fat from the lower extremities and progressive distal symmetric myopathy during adulthood. They had increased serum creatine kinase levels, hypertriglyceridemia and low levels of high-density lipoprotein cholesterol. Exome sequencing identified a novel homozygous NC_000019.9:g.42906092C>A variant on chromosome 19, leading to a NM_005357.3:c.3103G>T nucleotide change in coding DNA and corresponding p.(Glu1035*) protein change in hormone sensitive lipase (LIPE) gene as the disease-causing variant. Sanger sequencing further confirmed the segregation of the mutation in the family. Hormone sensitive lipase is the predominant regulator of lipolysis from adipocytes, releasing free fatty acids from stored triglycerides. The homozygous null LIPE mutation could result in marked inhibition of lipolysis from some adipose tissue depots and thus may induce an extremely rare phenotype of MSL and partial lipodystrophy in adulthood associated with complications of insulin resistance, such as diabetes, hypertriglyceridemia and hepatic steatosis.
Article
Full-text available
Dietary fat promotes pathological insulin resistance through chronic inflammation. The inactivation of inflammatory proteins produced by macrophages improves diet-induced diabetes, but how nutrient-dense diets induce diabetes is unknown. Membrane lipids affect the innate immune response, which requires domains that influence high-fat-diet-induced chronic inflammation and alter cell function based on phospholipid composition. Endogenous fatty acid synthesis, mediated by fatty acid synthase (FAS), affects membrane composition. Here we show that macrophage FAS is indispensable for diet-induced inflammation. Deleting Fasn in macrophages prevents diet-induced insulin resistance, recruitment of macrophages to adipose tissue and chronic inflammation in mice. We found that FAS deficiency alters membrane order and composition, impairing the retention of plasma membrane cholesterol and disrupting Rho GTPase trafficking-a process required for cell adhesion, migration and activation. Expression of a constitutively active Rho GTPase, however, restored inflammatory signalling. Exogenous palmitate was partitioned to different pools from endogenous lipids and did not rescue inflammatory signalling. However, exogenous cholesterol, as well as other planar sterols, did rescue signalling, with cholesterol restoring FAS-induced perturbations in membrane order. Our results show that the production of endogenous fat in macrophages is necessary for the development of exogenous-fat-induced insulin resistance through the creation of a receptive environment at the plasma membrane for the assembly of cholesterol-dependent signalling networks.
Article
Full-text available
DAVID bioinformatics resources consists of an integrated biological knowledgebase and analytic tools aimed at systematically extracting biological meaning from large gene/protein lists. This protocol explains how to use DAVID, a high-throughput and integrated data-mining environment, to analyze gene lists derived from high-throughput genomic experiments. The procedure first requires uploading a gene list containing any number of common gene identifiers followed by analysis using one or more text and pathway-mining tools such as gene functional classification, functional annotation chart or clustering and functional annotation table. By following this protocol, investigators are able to gain an in-depth understanding of the biological themes in lists of genes that are enriched in genome-scale studies.
Article
Full-text available
Chronic low-grade inflammation of adipose tissue plays a crucial role in the pathophysiology of obesity. Immunohistological microscopic analysis in obese fat tissue has demonstrated the infiltration of several immune cells such as macrophages, but dynamics of immune cells have not been fully elucidated and clarified. Here, by using intravital multiphoton imaging technique, to our knowledge for the first time, we analyzed and visualized the inflammatory processes in adipose tissue under high-fat and high-sucrose (HF/HS) diet with lysozyme M-EGFP transgenic (LysM(EGFP)) mice whose EGFP was specifically expressed in the myelomonocytic lineage. Mobility of LysM(EGFP)-positive macrophages was shown to be activated just 5 d after HF/HS diet, when the distinct hypertrophy of adipocytes and the accumulation of macrophages still have not become prominent. Significant increase of S100A8 was detected in mature adipocyte fraction just 5 d after HF/HS diet. Recombinant S100A8 protein stimulated chemotactic migration in vitro and in vivo, as well as induced proinflammatory molecules, both macrophages and adipocytes, such as TNF-α and chemokine (C-C motif) ligand 2. Finally, an antibody against S100A8 efficiently suppressed the HF/HS diet-induced initial inflammatory change, i.e., increased mobilization of adipose LysM(EGFP)-positive macrophages, and ameliorated HF/HS diet-induced insulin resistance. In conclusion, time-lapse intravital multiphoton imaging of adipose tissues identified the very early event exhibiting increased mobility of macrophages, which may be triggered by increased expression of adipose S100A8 and results in progression of chronic inflammation in situ.
Article
Full-text available
The search for effective treatments for obesity and its comorbidities is of prime importance. We previously identified IKK-ε and TBK1 as promising therapeutic targets for the treatment of obesity and associated insulin resistance. Here we show that acute inhibition of IKK-ε and TBK1 with amlexanox treatment increases cAMP levels in subcutaneous adipose depots of obese mice, promoting the synthesis and secretion of the cytokine IL-6 from adipocytes and preadipocytes, but not from macrophages. IL-6, in turn, stimulates the phosphorylation of hepatic Stat3 to suppress expression of genes involved in gluconeogenesis, in the process improving glucose handling in obese mice. Preliminary data in a small cohort of obese patients show a similar association. These data support an important role for a subcutaneous adipose tissue-liver axis in mediating the acute metabolic benefits of amlexanox on glucose metabolism, and point to a new therapeutic pathway for type 2 diabetes.
Article
Full-text available
Accumulation of fat mass in obesity may result from hypertrophy and/or hyperplasia and is frequently associated with adipose tissue (AT) dysfunction in adults. Here, we assessed early alterations in AT biology and function by comprehensive experimental and clinical characterization of 171 AT samples from lean and obese children aged 0 to 18 years.We show an increase in adipocyte size and number in obese compared to lean children beginning in early childhood. These alterations in AT composition in obese children were accompanied by decreased basal lipolytic activity and significantly enhanced stromal vascular cell proliferation in vitro, potentially underlying the hypertrophy and hyperplasia seen in obese children, respectively. Furthermore, macrophage infiltration, including the formation of crown-like structures, was increased in AT of obese children from 6 years on, and was associated with higher hsCRP serum levels. Clinically, adipocyte hypertrophy was not only associated with leptin serum levels, but was highly and independently correlated with HOMA-IR as a marker of insulin resistance in children.In summary, we show that adipocyte hypertrophy is linked to increased inflammation in AT in obese children thereby providing evidence that obesity-associated AT dysfunction develops in early childhood and is related to insulin resistance.
Article
Full-text available
Cloning and sequencing of the upstream region of the gene of the CC chemokine HCC-1 led to the discovery of an adjacent gene coding for a CC chemokine that was named ``HCC-2.'' The two genes are separated by 12-kbp and reside in a head-to-tail orientation on chromosome 17. At variance with the genes for HCC-1 and other human CC chemokines, which have a three-exon-two-intron structure, the HCC-2 gene consists of four exons and three introns. Expression of HCC-2 and HCC-1 as studied by Northern analysis revealed, in addition to the regular, monocistronic mRNAs, a common, bicistronic transcript. In contrast to HCC-1, which is expressed constitutively in numerous human tissues, HCC-2 is expressed only in the gut and the liver. HCC-2 shares significant sequence homology with CKbeta 8 and the murine chemokines C10, CCF18/MRP-2, and macrophage inflammatory protein 1gamma , which all contain six instead of four conserved cysteines. The two additional cysteines of HCC-2 form a third disulfide bond, which anchors the COOH-terminal domain to the core of the molecule. Highly purified recombinant HCC-2 was tested on neutrophils, eosinophils, monocytes, and lymphocytes and was found to exhibit marked functional similarities to macrophage inflammatory protein 1alpha . It is a potent chemoattractant and inducer of enzyme release in monocytes and a moderately active attractant for eosinophils. Desensitization studies indicate that HCC-2 acts mainly via CC chemokine receptor CCR1.
Article
Full-text available
In four 24-week controlled studies, the antihyperglycaemic efficacy of saxagliptin was demonstrated in patients with type 2 diabetes mellitus as add-on therapy to glyburide, a thiazolidinedione, or metformin, and when used in initial combination with metformin vs. metformin monotherapy in drug-naive patients. Data from these studies were analysed to compare the proportions of patients who achieved specific reductions from baseline in glycated haemoglobin [HbA1c ; reductions of ≥ 0.5% and ≥ 0.7% in all studies (prespecified); reductions ≥ 1.0% in the add-on studies and ≥ 1.0% to ≥ 2.5% in the initial combination study (post hoc)] for saxagliptin vs. comparator at week 24. We report overall rates of glycaemic response defined by these reductions in HbA1c and rates of response without experiencing hypoglycaemia. Large glycaemic response rates were higher with saxagliptin 2.5 and 5 mg/day than with comparator (HbA1c ≥ 1.0%, 31.7-50.3% vs. 10.3-20.0%) as add-on therapy and higher with saxagliptin 5 mg/day as initial combination with metformin than with metformin monotherapy (HbA1c ≥ 2.0%, 68.3% vs. 49.8%) in drug-naive patients. Addition of saxagliptin was associated with a low incidence of hypoglycaemia; overall response rates and response rates excluding patients who experienced hypoglycaemia were similar. Analysis of several demographic and baseline clinical variables revealed no consistent correlations with response to saxagliptin. Whether receiving saxagliptin as an add-on therapy to glyburide, a thiazolidinedione, or metformin or in initial combination with metformin, a greater percentage of patients achieve clinically relevant large reductions in HbA1c vs. comparator, with a low incidence of hypoglycaemia.
Article
Full-text available
Emerging evidence suggests that inflammation provides a link between obesity and insulin resistance. The noncanonical IκB kinases IKK-ɛ and TANK-binding kinase 1 (TBK1) are induced in liver and fat by NF-κB activation upon high-fat diet feeding and in turn initiate a program of counterinflammation that preserves energy storage. Here we report that amlexanox, an approved small-molecule therapeutic presently used in the clinic to treat aphthous ulcers and asthma, is an inhibitor of these kinases. Treatment of obese mice with amlexanox elevates energy expenditure through increased thermogenesis, producing weight loss, improved insulin sensitivity and decreased steatosis. Because of its record of safety in patients, amlexanox may be an interesting candidate for clinical evaluation in the treatment of obesity and related disorders.
Article
Full-text available
The hypertrophied white adipose tissue (WAT) during human obesity produces inflammatory mediators, including cytokines (IL-6 and TNFα) and chemokines ([C-C motif] chemokine ligand 2 and IL-8). These inflammatory factors are preferentially produced by the nonadipose cells, particularly the adipose tissue infiltrating macrophages. We identified the chemokine (C-X-C motif) ligand 2 (CXCL2) by a transcriptomic approach. Because CXCL2 could represent a WAT-produced chemokine, we explored its role in obesity-associated inflammation. CXCL2 levels in serum and mRNA in WAT were higher in obese subjects compared with lean ones. CXCL2 secretions were higher in sc and visceral (vis) WAT from obese compared with lean subjects. In vis WAT, CXCL2 mRNA expression was higher in macrophages compared with other WAT cells and positively correlated with the inflammatory macrophage markers TNFα and IL-6. CXCL2 triggered the in vitro adhesion of the neutrophils, its selective cell targets, to endothelial cells (ECs) of vis WAT (vis WAT-ECs). Immunohistological analysis indicated that activated neutrophils were adherent to the endothelium of vis WAT from human obese subjects. Blood neutrophils from obese subjects released high levels of proinflammatory mediators (IL-8, chemokine motif ligand 2 [CCL2], matrix metalloproteinase [MMP] 9, and myeloperoxidase [MPO]). Visceral WAT-ECs, treated by neutrophil-conditioned media prepared from obese subjects, displayed an increase of the expression of inflammatory molecules associated with senescence and angiogenic capacities. To conclude, CXCL2, a WAT-produced chemokine being up-regulated in obesity, stimulates neutrophil adhesion to vis WAT-ECs. Activated neutrophils in obesity may influence vis WAT-ECs functions and contribute to WAT inflammation.
Article
Full-text available
OBJECTIVE To evaluate whether impaired fasting glucose (IFG) or the combination of IFG and impaired glucose tolerance (IGT) is associated with progressive abnormalities of cardiac geometry and function.RESEARCH DESIGN AND METHODS We studied 562 nondiabetic (326 women), nonhypertensive participants of the second Strong Heart Study exam, without prevalent cardiovascular (CV) disease and with estimated glomerular filtration rate ≥60 mL/min/1.73 m(2) (age 46-65 years, 198 with isolated IFG [35%], and 132 with combined IFG and IGT [23%]). Anthropometric parameters, insulin resistance, fibrinogen, C-reactive protein (CRP), lipid profile, blood pressure (BP), and echocardiographic parameters were compared with 232 participants with normal glucose tolerance (NGT).RESULTSBMI, prevalence of central obesity, homeostatic model assessment index of insulin resistance, plasma triglycerides, fibrinogen, and CRP increased progressively across categories of glucose intolerance (P < 0.0001), with the IFG + IGT group having higher values than those with isolated IFG (0.05 < P < 0.0001). Compared with NGT, both IFG and IFG+IGT exhibited greater left ventricular (LV) mass (P < 0.0001) and lower Doppler early peak rapid filling velocity to peak atrial filling velocity ratio (P < 0.005), without differences in LV systolic function. The odds of LV hypertrophy (LV mass index >46.7 in women or >49.2 g/m(2.7) in men) was 3.5 in IFG participants (95% CI 0.68-17.76; P = NS) and 9.76 (2.03-46.79; P = 0.004) in IFG + IGT, compared with NGT, after adjustment for age, sex, heart rate, systolic BP, and waist circumference (WC). In the overall sample, LV mass index was associated with WC (P = 0.033), CRP (P = 0.027), and 2-h oral glucose tolerance test (P = 0.001) independently of confounders.CONCLUSIONS Cardiometabolic profile and markers of inflammation are more severely altered in men and women with both IFG and IGT compared with those with IFG alone. These individuals, in the absence of hypertension, have a 10-fold greater probability of preclinical CV disease (LV hypertrophy).
Article
Full-text available
Differential analysis of gene and transcript expression using high-throughput RNA sequencing (RNA-seq) is complicated by several sources of measurement variability and poses numerous statistical challenges. We present Cuffdiff 2, an algorithm that estimates expression at transcript-level resolution and controls for variability evident across replicate libraries. Cuffdiff 2 robustly identifies differentially expressed transcripts and genes and reveals differential splicing and promoter-preference changes. We demonstrate the accuracy of our approach through differential analysis of lung fibroblasts in response to loss of the developmental transcription factor HOXA1, which we show is required for lung fibroblast and HeLa cell cycle progression. Loss of HOXA1 results in significant expression level changes in thousands of individual transcripts, along with isoform switching events in key regulators of the cell cycle. Cuffdiff 2 performs robust differential analysis in RNA-seq experiments at transcript resolution, revealing a layer of regulation not readily observable with other high-throughput technologies.
Article
Full-text available
Motivation: Accurate alignment of high-throughput RNA-seq data is a challenging and yet unsolved problem because of the non-contiguous transcript structure, relatively short read lengths and constantly increasing throughput of the sequencing technologies. Currently available RNA-seq aligners suffer from high mapping error rates, low mapping speed, read length limitation and mapping biases. Results: To align our large (>80 billon reads) ENCODE Transcriptome RNA-seq dataset, we developed the Spliced Transcripts Alignment to a Reference (STAR) software based on a previously undescribed RNA-seq alignment algorithm that uses sequential maximum mappable seed search in uncompressed suffix arrays followed by seed clustering and stitching procedure. STAR outperforms other aligners by a factor of >50 in mapping speed, aligning to the human genome 550 million 2 × 76 bp paired-end reads per hour on a modest 12-core server, while at the same time improving alignment sensitivity and precision. In addition to unbiased de novo detection of canonical junctions, STAR can discover non-canonical splices and chimeric (fusion) transcripts, and is also capable of mapping full-length RNA sequences. Using Roche 454 sequencing of reverse transcription polymerase chain reaction amplicons, we experimentally validated 1960 novel intergenic splice junctions with an 80-90% success rate, corroborating the high precision of the STAR mapping strategy. Availability and implementation: STAR is implemented as a standalone C++ code. STAR is free open source software distributed under GPLv3 license and can be downloaded from http://code.google.com/p/rna-star/.
Article
Full-text available
To evaluate the effects of canagliflozin, a sodium-glucose cotransporter 2 inhibitor, in type 2 diabetes mellitus inadequately controlled with metformin monotherapy. This was a double-blind, placebo-controlled, parallel-group, multicenter, dose-ranging study in 451 subjects randomized to canagliflozin 50, 100, 200, or 300 mg once daily (QD) or 300 mg twice daily (BID), sitagliptin 100 mg QD, or placebo. Primary end point was change in A1C from baseline through week 12. Secondary end points included change in fasting plasma glucose (FPG), body weight, and overnight urinary glucose-to-creatinine ratio. Safety and tolerability were also assessed. Canagliflozin was associated with significant reductions in A1C from baseline (7.6-8.0%) to week 12: -0.79, -0.76, -0.70, -0.92, and -0.95% for canagliflozin 50, 100, 200, 300 mg QD and 300 mg BID, respectively, versus -0.22% for placebo (all P < 0.001) and -0.74% for sitagliptin. FPG was reduced by -16 to -27 mg/dL, and body weight was reduced by -2.3 to -3.4%, with significant increases in urinary glucose-to-creatinine ratio. Adverse events were transient, mild to moderate, and balanced across arms except for a non-dose-dependent increase in symptomatic genital infections with canagliflozin (3-8%) versus placebo and sitagliptin (2%). Urinary tract infections were reported without dose dependency in 3-9% of canagliflozin, 6% of placebo, and 2% of sitagliptin arms. Overall incidence of hypoglycemia was low. Canagliflozin added onto metformin significantly improved glycemic control in type 2 diabetes and was associated with low incidence of hypoglycemia and significant weight loss. The safety/tolerability profile of canagliflozin was favorable except for increased frequency of genital infections in females.
Article
Full-text available
Obese fat pads are frequently undervascularized and hypoxic, leading to increased fibrosis, inflammation, and ultimately insulin resistance. We hypothesized that VEGF-A-induced stimulation of angiogenesis enables sustained and sufficient oxygen and nutrient exchange during fat mass expansion, thereby improving adipose tissue function. Using a doxycycline (Dox)-inducible adipocyte-specific VEGF-A overexpression model, we demonstrate that the local up-regulation of VEGF-A in adipocytes improves vascularization and causes a "browning" of white adipose tissue (AT), with massive up-regulation of UCP1 and PGC1α. This is associated with an increase in energy expenditure and resistance to high fat diet-mediated metabolic insults. Similarly, inhibition of VEGF-A-induced activation of VEGFR2 during the early phase of high fat diet-induced weight gain, causes aggravated systemic insulin resistance. However, the same VEGF-A-VEGFR2 blockade in ob/ob mice leads to a reduced body-weight gain, an improvement in insulin sensitivity, a decrease in inflammatory factors, and increased incidence of adipocyte death. The consequences of modulation of angiogenic activity are therefore context dependent. Proangiogenic activity during adipose tissue expansion is beneficial, associated with potent protective effects on metabolism, whereas antiangiogenic action in the context of preexisting adipose tissue dysfunction leads to improvements in metabolism, an effect likely mediated by the ablation of dysfunctional proinflammatory adipocytes.
Article
Full-text available
We estimated the heritability of individual differences in beta cell function after a mixed meal test designed to assess a wide range of classical and model-derived beta cell function parameters. A total of 183 healthy participants (77 men), recruited from the Netherlands Twin Register, took part in a 4 h protocol, which included a mixed meal test. Participants were Dutch twin pairs and their siblings, aged 20 to 49 years. All members within a family were of the same sex. Insulin sensitivity, insulinogenic index, insulin response and postprandial glycaemia were assessed, as well as model-derived parameters of beta cell function, in particular beta cell glucose sensitivity and insulin secretion rates. Genetic modelling provided the heritability of all traits. Multivariate genetic analyses were performed to test for overlap in the genetic factors influencing beta cell function, waist circumference and insulin sensitivity. Significant heritabilities were found for insulinogenic index (63%), beta cell glucose sensitivity (50%), insulin secretion during the first 2 h postprandial (42-47%) and postprandial glycaemia (43-52%). Genetic factors influencing beta cell glucose sensitivity and insulin secretion during the first 30 postprandial min showed only negligible overlap with the genetic factors that influence waist circumference and insulin sensitivity. The highest heritability for postprandial beta cell function was found for the insulinogenic index, but the most specific indices of heritability of beta cell function appeared to be beta cell glucose sensitivity and the insulin secretion rate during the first 30 min after a mixed meal.
Article
Full-text available
The emergence of chronic inflammation during obesity in the absence of overt infection or well-defined autoimmune processes is a puzzling phenomenon. The Nod-like receptor (NLR) family of innate immune cell sensors, such as the nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (Nlrp3, but also known as Nalp3 or cryopyrin) inflammasome are implicated in recognizing certain nonmicrobial originated 'danger signals' leading to caspase-1 activation and subsequent interleukin-1β (IL-1β) and IL-18 secretion. We show that calorie restriction and exercise-mediated weight loss in obese individuals with type 2 diabetes is associated with a reduction in adipose tissue expression of Nlrp3 as well as with decreased inflammation and improved insulin sensitivity. We further found that the Nlrp3 inflammasome senses lipotoxicity-associated increases in intracellular ceramide to induce caspase-1 cleavage in macrophages and adipose tissue. Ablation of Nlrp3 in mice prevents obesity-induced inflammasome activation in fat depots and liver as well as enhances insulin signaling. Furthermore, elimination of Nlrp3 in obese mice reduces IL-18 and adipose tissue interferon-γ (IFN-γ) expression, increases naive T cell numbers and reduces effector T cell numbers in adipose tissue. Collectively, these data establish that the Nlrp3 inflammasome senses obesity-associated danger signals and contributes to obesity-induced inflammation and insulin resistance.
Article
Full-text available
CCN1 (CYR61) is a matricellular protein that is highly expressed at sites of inflammation and wound repair. In these contexts, CCN1 can modify the activities of specific cytokines, enabling TNF-alpha to be cytotoxic without blocking NF-kappaB activity and enhancing the apoptotic activity of Fas ligand and TRAIL. In this paper, we show that CCN1 supports the adhesion of macrophages through integrin alpha(M)beta(2) and syndecan-4, activates NFkappaB-mediated transcription, and induces a proinflammatory genetic program characteristic of classically activated M1 macrophages that participates in Th1 responses. The effects of CCN1 include upregulation of cytokines (TNF-alpha, IL-1alpha, IL-1beta, IL-6, and IL-12b), chemokines (MIP-1alpha; MCP-3; growth-related oncogenes 1 and 2; and inflammatory protein 10), and regulators of oxidative stress and complement (inducible NO synthase and C3) and downregulation of specific receptors (TLR4 and IL-10Rbeta) and anti-inflammatory factors (TGF-beta1). CCN1 regulates this genetic program through at least two distinct mechanisms: an immediate-early response resulting from direct activation of NF-kappaB by CCN1, leading to the synthesis of cytokines including TNF-alpha and inflammatory protein 10; and a delayed response resulting from CCN1-induced TNF-alpha, which acts as an autocrine/paracrine mediator to activate the expression of other cytokines including IL-1beta and IL-6. These results identify CCN1 as a novel component of the extracellular matrix that activates proinflammatory genes in macrophages, implicating its role in regulating macrophage function during inflammation.
Article
Full-text available
It is expected that emerging digital gene expression (DGE) technologies will overtake microarray technologies in the near future for many functional genomics applications. One of the fundamental data analysis tasks, especially for gene expression studies, involves determining whether there is evidence that counts for a transcript or exon are significantly different across experimental conditions. edgeR is a Bioconductor software package for examining differential expression of replicated count data. An overdispersed Poisson model is used to account for both biological and technical variability. Empirical Bayes methods are used to moderate the degree of overdispersion across transcripts, improving the reliability of inference. The methodology can be used even with the most minimal levels of replication, provided at least one phenotype or experimental condition is replicated. The software may have other applications beyond sequencing data, such as proteome peptide count data. Availability: The package is freely available under the LGPL licence from the Bioconductor web site (http://bioconductor.org). Contact: mrobinson@wehi.edu.au
Article
Full-text available
Apart from fasting blood glucose (FBG) and insulin (FBI), oral glucose tolerance test (OGTT) is also used in calculating insulin sensitivity. During OGTT, insulin secretion may not reflect normal physiological insulin secretion. Based on this idea, hepatic and whole body insulin sensitivity rates were tested during OGTT and mixed meal test (MMT) in obese subjects. Thirty-one women with Quantitative Insulin Sensitivity Check Index (QUICKI) values below 0.350 and body mass index (BMI) >or=30 were included into the study. OGTT with 75-g glucose and MMT 300 kcal were applied to all cases. Data obtained from OGTT and MMT were used in the assessment of insulin sensitivity with Hemostasis of Model Assessment-Insulin Resistance (HOMA-IR) and Matsuda's Composite Whole Body Insulin Sensitivity Index (Matsuda's ISI). Mean BMI, FBG, and FBI were 36.8 +/- 3.9 kg/m(2), 100.5 +/- 0.10 mg/dl, 16.2 +/- 5.3 microg/ml, respectively. QUICKI was 0.31 +/- 0.01 and HOMA-IR was 3.71 +/- 0.88. Matsuda's ISI derived from OGTT was 6.96 +/- 3.35 and from MMT was 11.32 +/- 6.61. In analysis, it was demonstrated that there was a correlation between HOMA-IR, QUICKI, and Matsuda's ISIs derived from OGTT and MMT. Comparing the time periods separately, it was detected that despite similar increment in insulin levels, glucose levels were higher in OGTT than MMT at 15 and 30 min. Consequently, Matsuda's ISI was demonstrated to be effectively used with the data of MMT, as used with OGTT. Moreover, MMT was shown to be in parallel to physiologic insulin secretion and reflect pancreatic functions better compared to OGTT.
Article
Full-text available
Functional analysis of large gene lists, derived in most cases from emerging high-throughput genomic, proteomic and bioinformatics scanning approaches, is still a challenging and daunting task. The gene-annotation enrichment analysis is a promising high-throughput strategy that increases the likelihood for investigators to identify biological processes most pertinent to their study. Approximately 68 bioinformatics enrichment tools that are currently available in the community are collected in this survey. Tools are uniquely categorized into three major classes, according to their underlying enrichment algorithms. The comprehensive collections, unique tool classifications and associated questions/issues will provide a more comprehensive and up-to-date view regarding the advantages, pitfalls and recent trends in a simpler tool-class level rather than by a tool-by-tool approach. Thus, the survey will help tool designers/developers and experienced end users understand the underlying algorithms and pertinent details of particular tool categories/tools, enabling them to make the best choices for their particular research interests.
Article
Full-text available
Amlexanox markedly inhibits histamine release from rat mast cells. To clarify the mechanism of this inhibition, we investigated the effect of amlexanox on cAMP content, which, when increased, inhibits histamine release in rat peritoneal mast cells. At concentrations of 10(-8)-10(-6)M, amlexanox or isoproterenol increased the cAMP content of mast cells over that of control cells about 2-fold. When the mast cells were incubated with 10(-8), 10(-7) and 10(-6) M of amlexanox combined with 10(-7) M isoproterenol, the cAMP contents were synergistically increased 15-, 60- and 88-fold, respectively. 3-Isobutyl-1-methylxanthine (IBMX) at 10(-6)-10(-4) M increased the cAMP content 1.7-3.8-fold, and a combination of 10(-4) M IBMX and 10(-7) M isoproterenol synergistically increased the cAMP content 41-fold. A combination of amlexanox and IBMX synergistically increased the cAMP content 19-fold. The increase in cAMP content, when amlexanox and isoproterenol were combined, was transient; it peaked at 0.5 min after the drugs were administered, then decreased to 20-30% of the peak value about 2 min later. Pretreatment of mast cells with amlexanox reduced the effect of the combination of amlexanox and isoproterenol, indicating tachyphylaxis; pretreatment with IBMX had no such effect. The cAMP content of macrophages was also increased by amlexanox, but when combined with isoproterenol or PGE2, the effect was additive. Amlexanox inhibited cAMP phosphodiesterase in rat mast cells; its IC50 value was 1.4 X 10(-5) M, and its inhibitory activity was half that of IBMX.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Full-text available
A decreased mobilization of triglycerides may contribute to fat accumulation in adipocytes, leading to obesity. However, this hypothesis remains to be proven. In this study, epinephrine-induced lipid mobilization was investigated in vivo in nine markedly obese children (160+/-5% ideal body weight) aged 12.1+/-0.1 yr during the dynamic phase of fat deposition, compared with six age-matched nonobese children. As an in vivo index of lipolysis, we measured glycerol flux using a nonradioactive tracer dilution approach, and plasma free fatty acid concentrations. In the basal state, the obese children had a 30% lower rate of glycerol release per unit fat mass than the lean children. To study the regulation of lipolysis, epinephrine was infused stepwise at fixed doses of 0.75 and then 1. 50 microg/min in both groups. In lean children, glycerol flux and plasma free fatty acid increased to an average of 249-246% of basal values, respectively, in response to a mean plasma epinephrine of 396+/-41 pg/ml. The corresponding increase was only 55-72% in the obese children, although their mean plasma epinephrine reached 606+/-68 pg/ml. All obese and nonobese children, except an Arg64Trp heterozygote, were homozygotes for Trp at position 64 of their beta3-adrenoreceptor. The resistance of lipolysis to epinephrine showed no relationship with the Arg64 polymorphism of the beta3-adrenoreceptor gene. In summary, in vivo lipolysis, which mostly reflects the mobilization of lipid stores from subcutaneous adipose tissue, shows a decreased sensitivity to epinephrine in childhood onset obesity. Since our study was carried out in obese children during the dynamic phase of fat accumulation, the observed resistance to catecholamines might possibly be causative rather than the result of obesity.
Article
Summary Impaired angiogenesis has been implicated in adipose tissue dysfunction and the development of obesity and associated metabolic disorders. Here, we report the unexpected finding that vascular endothelial growth factor B (VEGFB) gene transduction into mice inhibits obesity-associated inflammation and improves metabolic health without changes in body weight or ectopic lipid deposition. Mechanistically, the binding of VEGFB to VEGF receptor 1 (VEGFR1, also known as Flt1) activated the VEGF/VEGFR2 pathway and increased capillary density, tissue perfusion, and insulin supply, signaling, and function in adipose tissue. Furthermore, endothelial Flt1 gene deletion enhanced the effect of VEGFB, activating the thermogenic program in subcutaneous adipose tissue, which increased the basal metabolic rate, thus preventing diet-induced obesity and related metabolic complications. In obese and insulin-resistant mice, Vegfb gene transfer, together with endothelial Flt1 gene deletion, induced weight loss and mitigated the metabolic complications, demonstrating the therapeutic potential of the VEGFB/VEGFR1 pathway.
Article
Low-grade tissue inflammation induced by obesity can result in insulin resistance, which in turn is a key cause of type 2 diabetes mellitus. Cells of the innate immune system produce cytokines and other factors that impair insulin signalling, which contributes to the connection between obesity and the onset of type 2 diabetes mellitus. Here, we review the innate immune cells involved in secreting inflammatory factors in the obese state. In the adipose tissue, these cells include proinflammatory adipose tissue macrophages and natural killer cells. We also discuss the role of innate immune cells, such as anti-inflammatory adipose tissue macrophages, eosinophils, group 2 innate lymphoid cells and invariant natural killer T cells, in maintaining an anti-inflammatory and insulin-sensitive environment in the lean state. In the liver, both Kupffer cells and recruited hepatic macrophages can contribute to decreased hepatic insulin sensitivity. Proinflammatory macrophages might also adversely affect insulin sensitivity in the skeletal muscle and pancreatic β-cell function. Finally, this Review provides an overview of the mechanisms for regulating proinflammatory immune responses that could lead to future therapeutic opportunities to improve insulin sensitivity.
Article
Methods for the quantification of beta-cell sensitivity to glucose (hyperglycemic clamp technique) and of tissue sensitivity to insulin (euglycemic insulin clamp technique) are described. Hyperglycemic clamp technique. The plasma glucose concentration is acutely raised to 125 mg/dl above basal levels by a priming infusion of glucose. The desired hyperglycemic plateau is subsequently maintained by adjustment of a variable glucose infusion, based on the negative feedback principle. Because the plasma glucose concentration is held constant, the glucose infusion rate is an index of glucose metabolism. Under these conditions of constant hyperglycemia, the plasma insulin response is biphasic with an early burst of insulin release during the first 6 min followed by a gradually progressive increase in plasma insulin concentration. Euglycemic insulin clamp technique. The plasma insulin concentration is acutely raised and maintained at approximately 100 muU/ml by a prime-continuous infusion of insulin. The plasma glucose concentration is held constant at basal levels by a variable glucose infusion using the negative feedback principle. Under these steady-state conditions of euglycemia, the glucose infusion rate equals glucose uptake by all the tissues in the body and is therefore a measure of tissue sensitivity to exogenous insulin.
Article
Summary: It is expected that emerging digital gene expression (DGE) technologies will overtake microarray technologies in the near future for many functional genomics applications. One of the fundamental data analysis tasks, especially for gene expression studies, involves determining whether there is evidence that counts for a transcript or exon are significantly different across experimental conditions. edgeR is a Bioconductor software package for examining differential expression of replicated count data. An overdispersed Poisson model is used to account for both biological and technical variability. Empirical Bayes methods are used to moderate the degree of overdispersion across transcripts, improving the reliability of inference. The methodology can be used even with the most minimal levels of replication, provided at least one phenotype or experimental condition is replicated. The software may have other applications beyond sequencing data, such as proteome peptide count data.Availability: The package is freely available under the LGPL licence from the Bioconductor web site (http://bioconductor.org).Contact: mrobinson@wehi.edu.au