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Publications (13)24.19 Total impact

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    ABSTRACT: Polycystic kidney disease (PKD) 2L1 protein is a member of the transient receptor potential (TRP) ion channel family. In circumvallate and foliate papillae, PKD2L1 is coexpressed with PKD1L3. PKD2L1 and PKD1L3 interact through their transmembrane domain and the resulting heteromer PKD1L3/PKD2L1 owns a unique channel property called 'off-responses' to acid stimulation, although PKD2L1 does not own this property by itself. To define the pharmacological properties of the PKD1L3/PKD2L1 channel, we developed a new method to effectively evaluate channel activity using human embryonic kidney 293T cells in which the channel was heterologously expressed. This method was applied to screen substances that potentially regulate it. We found that capsaicin and its analogs, which are TRPV1 agonists, inhibited the response to acid stimuli and that the capsaicin inhibition was reversible with an IC(50) of 32.5 μm. Capsaicin and its analogs are thus useful tools for physiological analysis of PKD1L3/PKD2L1 function.
    FEBS Journal 03/2012; 279(10):1857-70. · 4.25 Impact Factor
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    ABSTRACT: Acetic acid induces unique physiological responses in mammalian cells. Our previous study found that fura-2-loaded human embryonic kidney (HEK) 293T cells showed a robust intracellular fluorescence response immediately after stimulation with acetic acid, and no such response in the case of citric acid. In the present study, we aimed to identify the unique characteristics of acetic acid responsible for this phenomenon. We found that one such feature is its hydrophobicity. We also discovered that acetic acid induces cell responses by intracellular acidification. Of the components of acetic acid in solution (protons, acetate ions, and undissociated acetic acid), undissociated acetic acid might be the functional unit that penetrates the lipid bilayer of cell membranes to acidify the intracellular environment, thereby inducing cell responses. The method used in this study might be convenient in evaluating the intracellular acidification of cultured cells by acids in the external environment.
    Bioscience Biotechnology and Biochemistry 01/2012; 76(3):523-9. · 1.27 Impact Factor
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    ABSTRACT: We prepared 2-hydroxypalmitoyl-sphinganine (dihydroceramide) labeled with a stable isotope by culturing acetic acid bacteria with (13)C-labeled acetic acid. The GC/MS spectrum of the trimethylsilyl derivative of (13)C-labeled dihydroceramide gave molecular ions with an increased mass of 12-17 Da over that of nonlabeled dihydroceramide. The fragment ions derived from both sphinganine base and 2-hydroxypalmitate were confirmed to be labeled with the stable isotope in the spectrum. Therefore, (13)C-labeled dihydroceramide can be an extremely useful tool for analyzing sphingolipid metabolism. The purified [(13)C]dihydroceramide was administered orally to mice for 12 days, and the total sphingoid base fractions in various tissues were analyzed by GC/MS. The spectrum patterns specific to (13)C-labeled sphingoids were detected in the tissues tested. Sphinganine pools in skin epidermis, liver, skeletal muscle, and synapse membrane in brain were replaced by [(13)C]sphinganine at about 4.5, 4.0, 1.0, and 0.3%, respectively. Moreover, about 1.0% of the sphingosine pool in the liver was replaced by [(13)C]sphingosine, implying that exogenous dihydroceramide can be converted to sphingosine. These results clearly indicate that ingested dihydroceramide can be incorporated into various tissues, including brain, and metabolized to other sphingolipids.
    The Journal of Lipid Research 11/2010; 51(11):3389-95. · 4.39 Impact Factor
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    ABSTRACT: We have reported that acetic acid (AcOH) intake suppresses body fat mass and up-regulates the genes involved in fatty acid oxidation, but it is not clear whether the suppression of body fat mass by AcOH administration is due to an increase in energy expenditure (EE). In this study, we investigated to determine whether a single oral administration of AcOH would increase EE in C57BL/6J mice treated with 1.5% AcOH. The AcOH treatment group had significantly higher oxygen consumption (VO(2)), EE, and fat oxidation (FAT) than the water treatment group. These results suggest that a single administration of AcOH increases EE, resulting in suppression of body fat mass.
    Bioscience Biotechnology and Biochemistry 10/2010; 74(10):2158-9. · 1.27 Impact Factor
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    ABSTRACT: Acetic acid bacteria, fermentative microorganisms of traditional foods, have unique alkali-stable lipids (ASL), such as dihydroceramide which is a precursor of sphingolipids. Sphingolipids are important components of the brain tissue. We examined the effect of oral administration of ASL in a rat model of dementia (7-week-old, male) with a basal forebrain lesion. In a water maze test, the dementia model rats demonstrated poor spatial orientation. The administration of ASL (165 or 1650 mg/kg of body weight per day, for 14 days) produced a significant improvement in learning ability in the dementia model rats. In vitro experiments showed ASL had the ability to promote neurite outgrowth in pheochromocytoma (PC12) cells. Among the ASL components, dihydroceramide has the most potent effect on the differentiation of PC12 cells. It is highly possible that oral administration of dihydroceramide-containing ASL reverses the decline in cognitive function in dementia.
    Journal of Agricultural and Food Chemistry 03/2010; 58(7):4084-9. · 2.91 Impact Factor
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    ABSTRACT: The bioavailability of acetate in various vinegar supplements, e.g. as capsules and drinks, remains unclear. Thus, we conducted a cross-over clinical study in 30 healthy subjects. After an overnight fast, subjects received each test sample in a randomised sequence: 9 vinegar capsules (containing 750 mg acetic acid in total) with 150 mL of water, 100 mL of vinegar drink (containing 750 mg acetic acid), and 150 mL of water as reference. Blood samples were collected before (defined as 0 min), at 15, 30, 45, 60, 90, 120 and 180 min after each test sample intake. In the vinegar drink group, serum acetate concentration increased immediately after intake, peaked at 15 min and returned to baseline at 90 min. That in the vinegar capsule group rose slowly, peaked at 30 min and returned to baseline at 120 min. The peak values in both groups exceeded 200 µmol/L, the physiologically active concentration confirmed by in vitro experiment. In the reference group, levels remained constant throughout the 180-min period. The amount of absorbed acetate from the vinegar capsule group and the drink group was evaluated by the difference value of the area under the serum acetate concentration-time curve (AUC) between in each vinegar group and in the reference group (expressed as AUC(capsule-ref) and AUC(drink-ref ), respectively). AUC(capsule-ref) was about 80% of AUC(drink-ref ), but there was no significant difference between them.
    Journal of Nutritional Science and Vitaminology 01/2010; 56(4):266-9. · 0.99 Impact Factor
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    ABSTRACT: 50 The lipid matrix in the stratum corneum is important to the barrier function of mammalian skin. Ceramides are main components of intercellular lipids in the stratum corneum and play an essential role in skin barrier function. Moreover, recent investigations have demonstrated improvement in skin barrier properties after oral intake of ceramides of plant origin in mice and healthy adults. However, beneficial effects on skin barrier function by oral intake of ceramides other than those of plant origin have not been reported. It is known that acetic acid bacteria accumulate intracellular ceramides. Therefore, we examined the dietary effect of ceramide-containing acetic acid bacteria on skin barrier function. Studied were 3 groups, each comprised of 20 healthy adults with awareness of dry skin. The control group was given a placebo, the low acetic acid bacteria group (low-dose group) was given 55.6 mg dry acetic acid bacteria containing 400 μg ceramide, and the high acetic acid bacteria group (high-dose group) was administered 111.1 mg dry acetic acid bacteria containing 800 μg ceramide per day for 8 weeks. Transepidermal water loss (TEWL) and stratum corneum hydration (SCH) were measured as indexes of skin barrier function on the cheek, upper inner arm and back of the neck of all study subjects. The most marked effect was on the cheek, the area most exposed. On the cheek, the TEWL value increased significantly on week 4 after starting administration in the control group, but remained at the baseline level in both the low-dose and high-dose groups. In both the low-dose and high-dose groups, TEWL values decreased significantly on week 6. The SCH value increased significantly after 6 weeks administration in the control group, whereas in both the low-dose and high-dose groups the SCH value increased significantly after just 4 weeks of intake. This increase occurred within a shorter period than in the control group. These results suggest that oral intake of ceramide-containing acetic acid bacteria effects to maintain skin barrier function in healthy adults with awareness of dry skin. Abstract
    Anti-aging Medicine. 01/2010; 7(5):50-54.
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    ABSTRACT: We administered Acetobacter malorum NCI1683 (S24), containing a high concentration of dihydroceramide (7.2 mg/g of dry cell weight), consecutively to aged rats (male Crlj:Wistar rats, 22 months old). The ingestion of Acetobacter malorum for 89 d significantly extended the memory retention in passive avoidance tests, increased the release of acetylcholine with depolarization of brain synaptosomes and decreased the causative agents of neurodegenerative diseases in the cerebral cortices.
    Bioscience Biotechnology and Biochemistry 01/2010; 74(7):1498-500. · 1.27 Impact Factor
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    ABSTRACT: This study examined the effect of acetate on endothelial nitric oxide synthase (eNOS) in human umbilical vein endothelial cells (HUVECs) by immunoblotting assay and the ability of acetic acid to upregulate flow-mediated vasodilatation in humans. In HUVECs, acetate induced a biphasic increase in the phosphorylated form of eNOS. The amount of phosphorylated eNOS was significantly increased by exposure to 200 mumol/l acetate for 20 min (early phase) and for 4 h (late phase). The inhibitors of cAMP-dependent protein kinase (PKA) and AMP-activated protein kinase (AMPK) blocked acetate-induced eNOS phosphorylation in the early and the late phase respectively. Furthermore, in postmenopausal women, maximum forearm blood flow (FBF) in response to shear stress increased in the vinegar (acetic acid) administered group compared to the placebo group. These results suggest that acetic acid-induced eNOS phosphorylation contributes to upregulation of flow-mediated vasodilatation in humans.
    Bioscience Biotechnology and Biochemistry 01/2010; 74(5):1055-61. · 1.27 Impact Factor
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    ABSTRACT: Acetic acid (AcOH), a main component of vinegar, recently was found to suppress body fat accumulation in animal studies. Hence we investigated the effects of vinegar intake on the reduction of body fat mass in obese Japanese in a double-blind trial. The subjects were randomly assigned to three groups of similar body weight, body mass index (BMI), and waist circumference. During the 12-week treatment period, the subjects in each group ingested 500 ml daily of a beverage containing either 15 ml of vinegar (750 mg AcOH), 30 ml of vinegar (1,500 mg AcOH), or 0 ml of vinegar (0 mg AcOH, placebo). Body weight, BMI, visceral fat area, waist circumference, and serum triglyceride levels were significantly lower in both vinegar intake groups than in the placebo group. In conclusion, daily intake of vinegar might be useful in the prevention of metabolic syndrome by reducing obesity.
    Bioscience Biotechnology and Biochemistry 09/2009; 73(8):1837-43. · 1.27 Impact Factor
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    ABSTRACT: The polycystic kidney disease (PKD) 1L3-PKD2L1 channel is a candidate sour taste receptor expressed in mammalian taste receptor cells. Various acids are reported to activate PKD channels after the removal of the acid stimuli, but little information is available on the activation of these channels by acetic acid. It was difficult to analyze the PKD channel activation by acetic acid using Ca2+ imaging experiments because this acid induces a transient and nonspecific response in cultured cells. Here, we developed a novel method to evaluate PKD channel activation by acetic acid. Nonspecific responses were observed only over a short period after the application of acetic acid. In contrast, PKD channel activation evoked by acetic acid as well as citric acid was detected even at a later time point. This method revealed that PKD1L3-PKD2L1 channel activation by acetic acid was pH-dependent and occurred when the ambient pH was <3.1.
    Biochemical and Biophysical Research Communications 07/2009; 385(3):346-50. · 2.41 Impact Factor
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    ABSTRACT: We investigated the effect of acetic acid (AcOH) on the prevention of obesity in high-fat-fed mice. The mice were intragastrically administrated with water or 0.3 or 1.5% AcOH for 6 weeks. AcOH administration inhibited the accumulation of body fat and hepatic lipids without changing food consumption or skeletal muscle weight. Significant increases were observed in the expressions of genes for peroxisome-proliferator-activated receptor alpha (PPARalpha) and for fatty-acid-oxidation- and thermogenesis-related proteins: acetyl-CoA oxidase (ACO), carnitine palmitoyl transferase-1 (CPT-1), and uncoupling protein-2 (UCP-2), in the liver of the AcOH-treatment groups. PPARalpha, ACO, CPT-1, and UCP-2 gene expressions were increased in vitro by acetate addition to HepG2 cells. However, the effects were not observed in cells depleted of alpha2 5'-AMP-activated protein kinase (AMPK) by siRNA. In conclusion, AcOH suppresses accumulation of body fat and liver lipids by upregulation of genes for PPARalpha and fatty-acid-oxidation-related proteins by alpha2 AMPK mediation in the liver.
    Journal of Agricultural and Food Chemistry 06/2009; 57(13):5982-6. · 2.91 Impact Factor
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    ABSTRACT: 60 Acetic acid bacteria, the fermentative microorganisms of traditional foods, have unique and highly pure membrane lipid components such as sphingolipids (dihydroceramide). Sphingolipids are important components of brain tissue and many indirect studies demonstrated that ingestion of ceramide or its sphingolipid-derivatives might have beneficial effects on cognitive function. In a double-blind experiment, we tested whether continuous ingestion of the acetic acid bacterium, Acetobacter malorum NCI 1683 (S24) derived from fermented milk, could improve cognitive function in healthy middle-aged and elderly persons. Cognitive function was evaluated using the CogHealth battery of tasks that can detect slight variations. A 12-week supplement of Acetobacter malorum significantly shortened the response times of the working memory, the primary outcome of this study, compared to the placebo supplement (P<0.05). The working memory and delayed recall tasks in the low-dosage group (111 mg/day), and the choice reaction and delayed recall tasks in the high-dosage group (400 mg/day) were also improved at 8 or 12 weeks when compared to those observed before treatment (P<0.05). These results suggest that the continuous ingestion of Acetobacter malorum has a beneficial effect on cognitive function. No clinical problems were observed in the physical and medical examinations of any of the groups. These results and the historic experiences with eating fermented foods indicate that an intake of acetic acid bacteria is safe and beneficial for the life of elderly persons through the maintenance of cognitive function from the early stages of aging.
    Anti-Aging Medicine. 01/2009; 6:60-65.