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Weston WC, Hales KH, Hales DB. Flaxseed Increases Animal Lifespan and Reduces Ovarian Cancer Severity by Toxically Augmenting One-Carbon Metabolism. Molecules 2021; 26:molecules26185674. [PMID: 34577143 PMCID: PMC8471351 DOI: 10.3390/molecules26185674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 09/11/2021] [Accepted: 09/12/2021] [Indexed: 01/06/2023] Open
Abstract
We used an LC-MS/MS metabolomics approach to investigate one-carbon metabolism in the plasma of flaxseed-fed White Leghorn laying hens (aged 3.5 years). In our study, dietary flaxseed (via the activity of a vitamin B6 antagonist known as "1-amino d-proline") induced at least 15-fold elevated plasma cystathionine. Surprisingly, plasma homocysteine (Hcy) was stable in flaxseed-fed hens despite such highly elevated cystathionine. To explain stable Hcy, our data suggest accelerated Hcy remethylation via BHMT and MS-B12. Also supporting accelerated Hcy remethylation, we observed elevated S-adenosylmethionine (SAM), an elevated SAM:SAH ratio, and elevated methylthioadenosine (MTA), in flaxseed-fed hens. These results suggest that flaxseed increases SAM biosynthesis and possibly increases polyamine biosynthesis. The following endpoint phenotypes were observed in hens consuming flaxseed: decreased physiological aging, increased empirical lifespan, 9-14% reduced body mass, and improved liver function. Overall, we suggest that flaxseed can protect women from ovarian tumor metastasis by decreasing omental adiposity. We also propose that flaxseed protects cancer patients from cancer-associated cachexia by enhancing liver function.
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Affiliation(s)
- William C. Weston
- Department of Molecular, Cellular & Systemic Physiology, School of Medicine, Southern Illinois University, Carbondale, IL 62901, USA;
| | - Karen H. Hales
- Department of Obstetrics & Gynecology, School of Medicine, Southern Illinois University, Carbondale, IL 62901, USA;
| | - Dale B. Hales
- Department of Molecular, Cellular & Systemic Physiology, School of Medicine, Southern Illinois University, Carbondale, IL 62901, USA;
- Department of Obstetrics & Gynecology, School of Medicine, Southern Illinois University, Carbondale, IL 62901, USA;
- Correspondence: ; Tel.: +1-618-453-1544
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Wu F, Gu C, Bi Y, Guo Z, Wang Y. Folic acid rescues all-trans retinoic acid-induced anorectal malformations in rats. Birth Defects Res 2020; 112:1850-1856. [PMID: 33459508 DOI: 10.1002/bdr2.1810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 08/27/2020] [Accepted: 09/09/2020] [Indexed: 01/06/2023]
Abstract
BACKGROUND To investigate whether folic acid (FA) can rescue anorectal malformations (ARMs) induced by all-trans retinoic acid (ATRA) in rats. METHODS Pregnant Sprague-Dawley rats were randomly divided into three groups. In the model group, rats were administered ATRA (110 mg/kg) by gavage on the 10th day of gestation (E10.5). Rats in the rescue group were administered FA (40 mg/kg) by gavage 0.5 and 12 hr after treatment with ATRA. All fetuses were harvested on E20.5 using cesarean section and examined for ARMs. We recorded the weight, body length, tail length, and associated malformations of all the embryos. Hematoxylin and eosin staining was used to analyze the histopathology of the fetuses. RESULTS Control rats did not show any abnormalities. ARMs, tail deformities (less than half of normal length), and neural tube defects were found in 97.98% (97/99), 92.93% (92/99), and 32.32% (32/99) of the rats in the model group, respectively. The incidence of ARMs and tail deformities were 48.57% (51/105) and 35.24% (37/105), respectively, in the rescue rats; no neural tube defects were observed in these rats. The weight, body length, and tail length of the fetal rats in the rescue group were more than those in the model group, but less than those in the control group. CONCLUSION Taken together, FA rescued ARMs induced by ATRA in rats. Thus, FA may reduce the incidence of associated malformations and improve the growth and development of fetal rats.
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Affiliation(s)
- Fang Wu
- Department of Neonatal Gastrointestinal Surgery, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Chenchao Gu
- Department of Neonatal Gastrointestinal Surgery, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Yang Bi
- Pediatric Research Institute, Chongqing Key Laboratory of Pediatrics, Stem Cell Biology and Therapy Laboratory, Chongqing, P.R. China
| | - Zhenhua Guo
- Department of Neonatal Gastrointestinal Surgery, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Yi Wang
- Department of Neonatal Gastrointestinal Surgery, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders (Chongqing), China International Science and Technology Cooperation base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, P.R. China
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Olsen T, Blomhoff R. Retinol, Retinoic Acid, and Retinol-Binding Protein 4 are Differentially Associated with Cardiovascular Disease, Type 2 Diabetes, and Obesity: An Overview of Human Studies. Adv Nutr 2020; 11:644-666. [PMID: 31868199 PMCID: PMC7231588 DOI: 10.1093/advances/nmz131] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 11/12/2019] [Accepted: 11/26/2019] [Indexed: 12/12/2022] Open
Abstract
Vitamin A is a fat-soluble essential nutrient obtained from plant- and animal-based sources that has roles in growth, vision, and metabolism. Vitamin A circulates mainly as retinol bound to retinol-binding protein 4 (RBP4), and is delivered to tissues and converted to retinoic acid, which is a ligand for several nuclear receptors. In recent years, aspects of vitamin A metabolism have been under scrutiny with regards to the development of metabolic and lifestyle diseases including cardiovascular disease (CVD), type 2 diabetes mellitus (T2DM), and overweight and obesity in humans. Studies have mainly focused on RBP4 in this context, whereas the major circulating form, retinol, and the major bioactive form, retinoic acid, have been overlooked in this regard until recently. As one of the main roles of RBP4 is to deliver retinol to tissues for biological action, the associations of retinol and retinoic acid with these diseases must also be considered. In this review, we summarize and discuss recent and available evidence from human studies with focus on retinol, retinoic acid, and RBP4 and provide an overview of these crucial components of vitamin A metabolism in CVD, T2DM, and obesity. In summary, retinol was found to be both inversely and positively associated with CVD whereas the associations with T2DM and obesity were less clear. Although only a few studies have been published on retinoic acid, it was inversely associated with CVD. In contrast, serum RBP4 was mostly found to be positively associated with CVD, T2DM, and obesity. At present, it is difficult to ascertain why the reported associations differ depending on the compound under study, but there is a clear imbalance in the literature in disfavor of retinol and retinoic acid, which needs to be considered in future human studies.
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Affiliation(s)
- Thomas Olsen
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway,Address correspondence to TO (e-mail: )
| | - Rune Blomhoff
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway,Department of Clinical Service, Division of Cancer Medicine, Oslo University Hospital, Oslo, Norway
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Du Q, Luo ZC, Nuyt AM, Audibert F, Julien P, Wei SQ, Zhang DL, Fraser W, Levy E. Vitamin A and E Nutritional Status in Relation to Leptin, Adiponectin, IGF-I and IGF-II in Early Life - a Birth Cohort Study. Sci Rep 2018; 8:100. [PMID: 29311590 PMCID: PMC5758521 DOI: 10.1038/s41598-017-18531-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 12/12/2017] [Indexed: 01/26/2023] Open
Abstract
The metabolic health effects of vitamin A and E nutritional status in early life are largely unknown. We assessed whether vitamin A and vitamin E nutritional status may affect circulating leptin, adiponectin, insulin-like growth factor (IGF)-I and IGF-II levels in early life in humans. In a singleton birth cohort (n = 248), vitamin A and E nutritional status in fetuses/newborns were assessed by cord plasma concentrations of retinol, β-carotene, α- and γ-tocopherols. The primary outcomes were cord plasma leptin, adiponectin, IGF-I and IGF-II concentrations. Cord plasma retinol was significantly positively correlated to IGF-I in girls (r = 0.42, P < 0.0001) but not in boys (r = 0.14, P = 0.11). Adjusting for maternal and newborn's characteristics, one log unit increase in cord plasma retinol was associated with a 28.0% (95% CI: 11.1-47.5%) increase in IGF-I in girls (P < 0.001) but not in boys (P = 0.75). One log unit increment in cord plasma α-tocopherol was associated with a 6.6% (0.4-12.3%) decrease in adiponectin (P = 0.04), while one log unit increment in cord plasma γ-tocopherol was associated with a 21.2% (4.7-34.8%) decrease in leptin (P = 0.01). There may be a sex-specific association between retinol and IGF-I, a negative association between α-tocopherol and adiponectin, and a negative association between γ-tocopherol and leptin in early life in humans.
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Affiliation(s)
- Qinwen Du
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, 464200, China
- Department of Obstetrics and Gynecology, Sainte-Justine Hospital Research Center, University of Montreal, Montreal, H3T 1C5, Canada
| | - Zhong-Cheng Luo
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, 464200, China.
- Department of Obstetrics and Gynecology, Sainte-Justine Hospital Research Center, University of Montreal, Montreal, H3T 1C5, Canada.
| | - Anne Monique Nuyt
- Department of Pediatrics, University of Montreal, Montreal, H3T 1C5, Canada
| | - Francois Audibert
- Department of Obstetrics and Gynecology, Sainte-Justine Hospital Research Center, University of Montreal, Montreal, H3T 1C5, Canada
| | - Pierre Julien
- Departments of Medicine and Endocrinology and Nephrology, CHU-Quebec Laval University Research Center, Quebec City, G1V 4G2, Canada
| | - Shu-Qin Wei
- Department of Obstetrics and Gynecology, Sainte-Justine Hospital Research Center, University of Montreal, Montreal, H3T 1C5, Canada
| | - Dan-Li Zhang
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, 464200, China
- Department of Obstetrics and Gynecology, Sainte-Justine Hospital Research Center, University of Montreal, Montreal, H3T 1C5, Canada
| | - William Fraser
- Department of Obstetrics and Gynecology, Sainte-Justine Hospital Research Center, University of Montreal, Montreal, H3T 1C5, Canada
- Department of Obstetrics and Gynecology, University of Sherbrooke, Sherbrooke, J1H 5N4, Canada
| | - Emile Levy
- Department of Nutrition, Sainte-Justine Hospital Research Center, University of Montreal, Montreal, H3T 1C5, Canada
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Liao YJ, Lee TS, Twu YC, Hsu SM, Yang CP, Wang CK, Liang YC, Chen YMA. Glycine N-methyltransferase deficiency in female mice impairs insulin signaling and promotes gluconeogenesis by modulating the PI3K/Akt pathway in the liver. J Biomed Sci 2016; 23:69. [PMID: 27716281 PMCID: PMC5050923 DOI: 10.1186/s12929-016-0278-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 07/30/2016] [Indexed: 02/06/2023] Open
Abstract
Background Glycine N-methyltransferase (GNMT) is abundantly expressed in the normal liver but is down-regulated in liver cancer tissues. GNMT knockout (Gnmt−/−) mice can spontaneously develop chronic hepatitis, fatty liver, and liver cancer. We previously demonstrated that hepatic GNMT is decreased in high-fat-diet-induced type 2 diabetes mellitus, but its contribution to metabolic syndrome is unclear. Here we show that GNMT modulates key aspects of metabolic syndrome in mice. Methods Eleven-week-old Gnmt−/− and wild-type (WT) mice with a C57BL/6 genetic background were used in this study. The metabolic defects of GNMT deficiency were measured by glucose and insulin tolerance tests, lipid homeostasis, gluconeogenesis, and insulin signaling. Results Gnmt−/− mice, especially females, exhibited glucose intolerance and insulin resistance. However, their body fat and lean mass, food and water intakes, and energy expenditure did not differ from those of WT mice. In addition, glucose-stimulated insulin secretion and insulin-stimulated glucagon secretion were normal in the serum and pancreatic islets of Gnmt−/− mice. Importantly, we found that GNMT deficiency increased lipogenesis and triglycerides in the liver. The elevated triglycerides disrupted the ability of insulin to induce Akt and S6 ribosomal protein phosphorylation, and then triggered insulin resistance and gluconeogenesis in female Gnmt−/− mice. Conclusions Our data indicate that hepatic GNMT regulates lipid and glucose homeostasis, and provide insight into the development of insulin resistance through modulating the PI3K/Akt pathway. Electronic supplementary material The online version of this article (doi:10.1186/s12929-016-0278-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yi-Jen Liao
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Tzong-Shyuan Lee
- Department and Institute of Physiology, National Yang-Ming University, Taipei, Taiwan
| | - Yuh-Ching Twu
- Department of Biotechnology and Laboratory Science in Medicine, School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan
| | - Shih-Ming Hsu
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Ching-Ping Yang
- Department of Biotechnology and Laboratory Science in Medicine, School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan
| | - Chung-Kwe Wang
- Department of International Medicine, Taipei City Hospital Ranai Branch, Taipei, Taiwan
| | - Yu-Chih Liang
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Yi-Ming Arthur Chen
- Department of Microbiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
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6
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Karas Kuželički N. S-Adenosyl Methionine in the Therapy of Depression and Other Psychiatric Disorders. Drug Dev Res 2016; 77:346-356. [DOI: 10.1002/ddr.21345] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Nataša Karas Kuželički
- Chair of Clinical Biochemistry, Faculty of Pharmacy; University of Ljubljana, Askerceva 7; 1000 Ljubljana Slovenia
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7
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Sarris J, Price LH, Carpenter LL, Tyrka AR, Ng CH, Papakostas GI, Jaeger A, Fava M, Mischoulon D. Is S-Adenosyl Methionine (SAMe) for Depression Only Effective in Males? A Re-Analysis of Data from a Randomized Clinical Trial. PHARMACOPSYCHIATRY 2015; 48:141-4. [PMID: 26011569 DOI: 10.1055/s-0035-1549928] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
OBJECTIVE The aim of this study was to examine whether gender differences may have affected treatment response to S-adenosyl methionine (SAMe) in a recent failed randomized clinical trial (RCT) for adults with major depressive disorder. METHODS Data from a 2-site, 12-week, double-blind RCT (n=189) assessing the efficacy of SAMe vs. placebo and a comparator selective serotonin reuptake inhibitor (escitalopram) were subjected to post-hoc analyses to evaluate effects of patient gender on treatment response. RESULTS When assessing the efficacy outcomes within each gender separately, SAMe was superior to placebo among males (n=51), but not among females (n=62). Males showed a significant reduction of depression severity from baseline to study endpoint on the 17-item Hamilton Depression Rating Scale (4.3 point difference; p=0.034; d=0.95), while females did not show significant change. This finding emerged despite equivalence on baseline measures of depression severity between the gender groups. CONCLUSION RESULTS of this secondary data analysis suggest that gender might impact the antidepressant efficacy of SAMe, with greater therapeutic effect found in males. The underlying mechanism is still relatively unknown. Further work is needed to replicate this observation in independent samples.Clinicaltrials.gov identifier: NCT00101452.
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Affiliation(s)
- J Sarris
- The Melbourne Clinic, Department of Psychiatry, The University of Melbourne, Richmond, Melbourne, Australia
| | - L H Price
- Mood Disorders Research Program and Laboratory for Clinical and Translational Neuroscience, Butler Hospital, Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, RI, USA
| | - L L Carpenter
- Mood Disorders Research Program and Laboratory for Clinical and Translational Neuroscience, Butler Hospital, Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, RI, USA
| | - A R Tyrka
- Mood Disorders Research Program and Laboratory for Clinical and Translational Neuroscience, Butler Hospital, Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, RI, USA
| | - C H Ng
- The Melbourne Clinic, Department of Psychiatry, The University of Melbourne, Richmond, Melbourne, Australia
| | - G I Papakostas
- Depression Clinical and Research Program, Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - A Jaeger
- Depression Clinical and Research Program, Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - M Fava
- Depression Clinical and Research Program, Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - D Mischoulon
- Depression Clinical and Research Program, Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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8
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Chou WY, Zhao JF, Chen YMA, Lee KI, Su KH, Shyue SK, Lee TS. Role of glycine N-methyltransferase in experimental ulcerative colitis. J Gastroenterol Hepatol 2014; 29:494-501. [PMID: 24219143 DOI: 10.1111/jgh.12434] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/18/2013] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIM Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders with unclear etiology and mechanism(s). Glycine N-methyltransferase (GNMT) plays a central role in inflammatory diseases such as hepatitis and atherosclerosis. However, little is known about the impact of GNMT and the involved mechanism in the pathogenesis of IBD. In the current study, we investigated the role of GNMT in the mouse model of dextran sulfate sodium (DSS)-induced colitis. METHODS Protein expression was determined by Western blotting or immunohistochemistry. Histopathology was examined by hematoxylin and eosin staining. Levels of pro-inflammatory cytokines were evaluated by ELISA kits. RESULTS GNMT was expressed in the epithelium of the colon under normal conditions, and with DSS treatment, its expression was predominant in infiltrated leukocytes of lesions. Mice with genetic deletion of GNMT (GNMT(-/-) ) showed increased susceptibility to DSS induction of colitis, as revealed by the progression of colitis. Additionally, severe colonic inflammation, including increased crypt loss, leukocyte infiltration, and hemorrhage, was greater with DSS treatment in GNMT(-/-) than wild-type mice. Furthermore, the expression of adhesion molecule and inflammatory mediators in the colon was significantly higher with DSS treatment in GNMT(-/-) than wild-type mice. Moreover, loss of GNMT decreased cell apoptosis in colitis lesions with DSS treatment. CONCLUSIONS Collectively, our findings suggest that GNMT may be a crucial molecule in the pathogenesis of DSS-induced colitis. This finding may provide new information for a potential therapeutic target in treating IBD.
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Affiliation(s)
- Wen-Yueh Chou
- Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
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9
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Witham KL, Butcher NJ, Sugamori KS, Brenneman D, Grant DM, Minchin RF. 5-methyl-tetrahydrofolate and the S-adenosylmethionine cycle in C57BL/6J mouse tissues: gender differences and effects of arylamine N-acetyltransferase-1 deletion. PLoS One 2013; 8:e77923. [PMID: 24205029 PMCID: PMC3808426 DOI: 10.1371/journal.pone.0077923] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 09/12/2013] [Indexed: 01/14/2023] Open
Abstract
Folate catabolism involves cleavage of the C9-N10 bond to form p-aminobenzoylgluamate (PABG) and pterin. PABG is then acetylated by human arylamine N-acetyltransferase 1 (NAT1) before excretion in the urine. Mice null for the murine NAT1 homolog (Nat2) show several phenotypes consistent with altered folate homeostasis. However, the exact role of Nat2 in the folate pathway in vivo has not been reported. Here, we examined the effects of Nat2 deletion in male and female mice on the tissue levels of 5-methyl-tetrahydrofolate and the methionine-S-adenosylmethionine cycle. We found significant gender differences in hepatic and renal homocysteine, S-adenosylmethionine and methionine levels consistent with a more active methionine-S-adenosylmethionine cycle in female tissues. In addition, methionine levels were significantly higher in female liver and kidney. PABG was higher in female liver tissue but lower in kidney compared to male tissues. In addition, qPCR of mRNA extracted from liver tissue suggested a significantly lower level of Nat2 expression in female animals. Deletion of Nat2 affected liver 5- methyl-tetrahydrofolate in female mice but had little effect on other components of the methionine-S-adenosylmethionine cycle. No N-acetyl-PABG was observed in any tissues in Nat2 null mice, consistent with the role of Nat2 in PABG acetylation. Surprisingly, tissue PABG levels were similar between wild type and Nat2 null mice. These results show that Nat2 is not required to maintain tissue PABG homeostasis in vivo under normal conditions.
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Affiliation(s)
- Katey L. Witham
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Neville J. Butcher
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Kim S. Sugamori
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Debbie Brenneman
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Denis M. Grant
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Rodney F. Minchin
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia
- * E-mail:
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Kalhan SC, Wilson-Costello D. Prematurity and programming: contribution of neonatal Intensive Care Unit interventions. J Dev Orig Health Dis 2013; 4:121-33. [PMID: 25054678 PMCID: PMC4115292 DOI: 10.1017/s204017441200061x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Contemporary clinical practice for the care of the prematurely born babies has markedly improved their rates of survival so that most of these babies are expected to grow up to live a healthy functional life. Since the clinical follow-up is of short duration (years), only limited data are available to relate non-communicable diseases in adult life to events and interventions in the neonatal period. The major events that could have a programming effect include: (1) intrauterine growth restriction; (2) interruption of pregnancy with change in redox and reactive oxygen species (ROS) injury; (3) nutritional and pharmacological protocols for clinical care; and (4) nutritional care in the first 2 years resulting in accelerated weight gain. The available data are discussed in the context of perturbations in one carbon (methyl transfer) metabolism and its possible programming effects. Although direct evidence for genomic methylation is not available, clinical and experimental data on impact of redox and ROS, of low protein intake, excess methionine load and vitamin A, on methyl transfers are reviewed. The consequences of antenatal and postnatal administration of glucocorticoids are presented. Analysis of the correlates of insulin sensitivity at older age, suggests that premature birth is the major contributor, and is compounded by gain in weight during infancy. We speculate that premature interruption of pregnancy and neonatal interventions by affecting one carbon metabolism may cause programming effects on the immature baby. These can be additive to the effects of intrauterine environment (growth restriction) and are compounded by accelerated growth in early infancy.
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Affiliation(s)
- S C Kalhan
- 1 Department of Molecular Medicine, Cleveland Clinic, Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
| | - D Wilson-Costello
- 3 Department of Neonatology, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, OH, USA
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11
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Delgadillo D, Barbier O, Sierra G, Reyes JL. Retinoic acid improves recovery after nephrectomy and decreases renal TGF-β1 expression. Gender-related effects. Fundam Clin Pharmacol 2012. [DOI: 10.1111/fcp.12013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Dealmy Delgadillo
- Pharmacology Department, Center for Research and Advanced Studies; National Polytechnic Institute of Mexico (Cinvestav-IPN); C.P. 07360 Mexico City Mexico
| | - Olivier Barbier
- Toxicology Department, Center for Research and Advanced Studies; National Polytechnic Institute of Mexico (Cinvestav-IPN); C.P. 07360 Mexico City Mexico
| | - Gerardo Sierra
- Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies; National Polytechnic Institute of Mexico (Cinvestav-IPN); C.P. 07360 Mexico City Mexico
| | - Jose L. Reyes
- Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies; National Polytechnic Institute of Mexico (Cinvestav-IPN); C.P. 07360 Mexico City Mexico
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12
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Williams KT, Schalinske KL. Tissue-specific alterations of methyl group metabolism with DNA hypermethylation in the Zucker (type 2) diabetic fatty rat. Diabetes Metab Res Rev 2012; 28:123-31. [PMID: 21818837 DOI: 10.1002/dmrr.1281] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Altered methyl group and homocysteine metabolism were tissue-specific, persistent, and preceded hepatic DNA hypomethylation in type 1 diabetic rats. Similar metabolic perturbations have been shown in the Zucker (type 2) diabetic fatty (ZDF) rat in the pre-diabetic and early diabetic stages, but tissue specificity and potential impact on epigenetic marks are unknown, particularly during pathogenesis. METHODS ZDF (fa/fa) and lean (+/?) control rats were killed at 12 and 21 weeks of age, representing early and advanced diabetic conditions. Blood and tissues were analysed with respect to methyl group and homocysteine metabolism, including DNA methylation. RESULTS At 12 weeks, hepatic glycine N-methyltransferase (GNMT), methionine synthase, and cystathionine β-synthase (CBS) activity and/or abundance were increased in ZDF rats. At 21 weeks, GNMT activity was increased in liver and kidney; however, only hepatic CBS protein abundance (12 weeks) and betaine-homocysteine S-methyltransferase mRNA expression (21 weeks) were significantly elevated (78 and 100%, respectively). Hepatic phosphatidylethanolamine N-methyltransferase expression was also elevated in the ZDF rat. Homocysteine concentrations were decreased in plasma and kidney, but not in liver, at 12 and 21 weeks. In contrast to hepatic DNA hypomethylation in the type 1 diabetic rat, genomic DNA was hypermethylated at 12 and 21 weeks in the liver of ZDF rats, concomitant with an increase in DNA methyltransferase 1 expression at 21 weeks. CONCLUSIONS The pathogenesis of type 2 diabetes in the ZDF rat was associated with tissue and disease stage-specific aberrations of methyl group and homocysteine metabolism, with persistent hepatic global DNA hypermethylation.
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Affiliation(s)
- Kelly T Williams
- Interdepartmental Graduate Program in Nutritional Sciences, Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
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Marino M, Masella R, Bulzomi P, Campesi I, Malorni W, Franconi F. Nutrition and human health from a sex-gender perspective. Mol Aspects Med 2011; 32:1-70. [PMID: 21356234 DOI: 10.1016/j.mam.2011.02.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 01/25/2011] [Accepted: 02/18/2011] [Indexed: 02/07/2023]
Abstract
Nutrition exerts a life-long impact on human health, and the interaction between nutrition and health has been known for centuries. The recent literature has suggested that nutrition could differently influence the health of male and female individuals. Until the last decade of the 20th century, research on women has been neglected, and the results obtained in men have been directly translated to women in both the medicine and nutrition fields. Consequently, most modern guidelines are based on studies predominantly conducted on men. However, there are many sex-gender differences that are the result of multifactorial inputs, including gene repertoires, sex steroid hormones, and environmental factors (e.g., food components). The effects of these different inputs in male and female physiology will be different in different periods of ontogenetic development as well as during pregnancy and the ovarian cycle in females, which are also age dependent. As a result, different strategies have evolved to maintain male and female body homeostasis, which, in turn, implies that there are important differences in the bioavailability, metabolism, distribution, and elimination of foods and beverages in males and females. This article will review some of these differences underlying the impact of food components on the risk of developing diseases from a sex-gender perspective.
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Affiliation(s)
- Maria Marino
- Department of Biology, University Roma Tre, Viale Guglielmo Marconi 446, I-00146 Roma, Italy
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Lee CM, Shih YP, Wu CH, Chen YMA. Characterization of the 5' regulatory region of the human Glycine N-methyltransferase gene. Gene 2009; 443:151-7. [PMID: 19439180 DOI: 10.1016/j.gene.2009.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 04/13/2009] [Accepted: 05/04/2009] [Indexed: 10/20/2022]
Abstract
Glycine N-methyltransferase (GNMT) is a tumor susceptibility gene for both hepatocellular carcinoma and prostate cancer. We have previously characterized GNMT genomic structure and mapped its chromosomal localization to 6p12. For this study we identified a GNMT transcriptional start site at the 14th position upstream of the ATG codon. Electrophoretic mobility shift assay results indicate binding of the nuclear factor-Y (NF-Y) transcription factor to the CCAAT box (-71/-67) of the GNMT gene. Mutation assay results suggest that the nucleotide sequence in the -56/-47 region is a binding site for a putative transcriptional factor. The TATA-less core promoter (-133/+14) contains three major elements: an Sp1 site, CCAAT box, and a novel box within the CTGTCGGCTG sequence. One functional xenobiotic response element (XRE) located at the -104/-82 region is inducable by benzo[a]pyrene treatment. We believe our results have value for the study of GNMT transcriptional regulation.
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Affiliation(s)
- Cheng-Ming Lee
- AIDS Prevention and Research Center, National Yang-Ming University, Taipei 112, Taiwan
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15
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Chanson A, Cardinault N, Rock E, Martin JF, Souteyrand P, D'Incan M, Brachet P. Decreased plasma folate concentration in young and elderly healthy subjects after a short-term supplementation with isotretinoin. J Eur Acad Dermatol Venereol 2008; 22:94-100. [PMID: 18181979 DOI: 10.1111/j.1468-3083.2007.02386.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND In the last two decades, there has been an increasing use of isotretinoin (13-cis-retinoic acid or 13-CRA) for treatment of severe, and recently mild and moderate, acne in Westernized populations. Recent human and animal studies emphasized alterations caused by 13-CRA administration on folate-dependent, one-carbon metabolism. Folate deficiency and subsequent hyperhomocysteinemia increase the risk of degenerative diseases. OBJECTIVES We determine whether a short-term supplementation with 13-CRA alters folate status and homocysteinemia in young and elderly healthy human subjects. METHODS Twenty young and 20 elderly (age mean, 26.1 and 65.4 years, respectively) healthy male volunteers were supplemented with approximately 0.5 mg/kg/day of 13-CRA for 28 days. Fasting plasma concentrations of 13-CRA, 5-methyltetrahydrofolate (5-mTHF) as the main circulating form of folate, and homocysteine (Hcy), as well as haematologic parameters and biochemical markers of liver and renal function, were measured at baseline and at the end of supplementation. Statistical analyses were carried out using two-way anova and standard tests. RESULTS In both groups, isotretinoin supplementation caused a dramatic increase in the circulating concentration of 13-CRA and its derivatives. It also led to significant increases in serum triglyceride (P < 0.0001) and creatinine (P = 0.002) concentrations and gamma-glutamyltranspeptidase activity (P = 0.0001) and decrease in serum level of urea (P = 0.027). However, the latter four parameters remained within normal ranges. These changes were accompanied by a 17.7% and 13.5% decrease in the plasma level of 5-mTHF (P = 0.001) in the young and elderly volunteers, respectively. Supplementation with 13-CRA did not cause significant variations in their plasma Hcy concentration. However, the latter parameter seemed to respond differently in each group of age (P = 0.046). CONCLUSIONS Our data indicate that a 28-day supplementation with isotretinoin alters the plasma folate in young and old healthy individuals. This stresses the necessity of studying the long-term effects of retinoid therapy on folate status and homocysteinemia in acne patients, given that alteration in the latter parameters is known to increase the risk of degenerative diseases.
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Affiliation(s)
- A Chanson
- Human Nutrition Unit, Institut National de la Recherche Agronomique, Centre de Theix, Saint-Genes Champanelle, France
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16
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Abstract
While genetic studies have provided a wealth of information about health and disease, there is a growing awareness that individual characteristics are also determined by factors other than genetic sequences. These "epigenetic" changes broadly encompass the influence of the environment on gene regulation and expression and in a more narrow sense, describe the mechanisms controlling DNA methylation, histone modification and genetic imprinting. In this review, we focus on the epigenetic mechanisms that regulate adult (somatic) stem cell differentiation, beginning with the metabolic pathways and factors regulating chromatin structure and DNA methylation and the molecular biological tools that are currently available to study these processes. The role of these epigenetic mechanisms in manipulating adult stem cells is followed by a discussion of the challenges and opportunities facing this emerging field.
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Affiliation(s)
- Kenneth J Eilertsen
- Epigenetics and Nuclear Reprogramming Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA.
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Luka Z. Methyltetrahydrofolate in folate-binding protein glycine N-methyltransferase. VITAMINS AND HORMONES 2008; 79:325-45. [PMID: 18804700 DOI: 10.1016/s0083-6729(08)00411-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In mammals, folate is used as a carrier of one-carbon units (C(1)) in nucleic acids metabolism and biological methylation. Among all forms of folate the most abundant is 5-methyltetrahydrofolate (5-CH(3)-THF), which is of exceptional importance. Its distinctive role among other forms of folate is in its dual function. As a C(1) carrier it is used for synthesis of methionine by remethylation of homocysteine. In addition, 5-CH(3)-THF is bound to and inhibits glycine-N-methyltransferase (GNMT). GNMT is one of the key enzymes in methionine and S-adenosylmethionine (AdoMet) metabolism. It removes excess AdoMet by using it for methylation of glycine. The interaction of 5-CH(3)-THF and GNMT was proposed as an important regulatory mechanism in AdoMet metabolism and biological methylation. The recent discovery of human individuals with mutant GNMT and the study of a mouse model with the GNMT gene knocked out showed that inactivation of that enzyme, indeed, has a significant impact on AdoMet levels in the liver and plasma. The crystal structure of GNMT complexed with 5-CH(3)-THF revealed that there are two folate molecules bound to one tetrameric form of GNMT, which is a basis for establishing of mechanism of inhibition of GNMT. The role of GNMT as a folate-binding protein and how it affects one-carbon folate metabolism is discussed.
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Affiliation(s)
- Zigmund Luka
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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18
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Environment, diet and CpG island methylation: epigenetic signals in gastrointestinal neoplasia. Food Chem Toxicol 2007; 46:1346-59. [PMID: 17976883 DOI: 10.1016/j.fct.2007.09.101] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 09/14/2007] [Accepted: 09/19/2007] [Indexed: 12/26/2022]
Abstract
The epithelial surfaces of the mammalian alimentary tract are characterised by very high rates of cell proliferation and DNA synthesis, and in humans they are highly susceptible to cancer. The role of somatic mutations as drivers of carcinogenesis in the alimentary tract is well established, but the importance of gene silencing by epigenetic mechanisms is increasingly recognised. Methylation of CpG islands is an important component of the epigenetic code that regulates gene expression during development and normal cellular differentiation, and a number of genes are well known to become abnormally methylated during the development of tumours of the oesophagus, stomach and colorectum. Aberrant patterns of DNA methylation develop as a result of pathological processes such as chronic inflammation, and in response to various dietary factors, including imbalances in the supply of methyl donors, particularly folates, and exposure to DNA methyltransferase inhibitors, which include polyphenols and possibly isothiocyanates from plant foods. However the importance of these environmental interactions in human health and disease remains to be established. Recent moves to modify the exposure of human populations to folate, by mandatory supplementation of cereal foods, emphasise the importance of understanding the susceptibility of the human epigenome to dietary and other environmental effects.
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Hartz CS, Nieman KM, Jacobs RL, Vance DE, Schalinske KL. Hepatic phosphatidylethanolamine N-methyltransferase expression is increased in diabetic rats. J Nutr 2006; 136:3005-9. [PMID: 17116711 DOI: 10.1093/jn/136.12.3005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Phosphatidylcholine is an essential phospholipid that is synthesized by 2 different pathways, the CDP-choline pathway and the methylation of phosphatidylethanolamine by phosphatidylethanolamine N-methyltransferase (PEMT). Recent studies have suggested that PEMT is an important consumer of methyl groups from S-adenosylmethionine (SAM) and is a major determinant of homocysteine pools. Diabetes and all-trans-retinoic acid (ATRA) have been shown to alter the activities of several enzymes involved in methyl group metabolism. Thus, we investigated how diabetes and ATRA, individually and together, affect SAM-dependent phospholipid methylation. Rats received a single injection of streptozotocin (60 mg/kg body wt) or vehicle followed by administration of ATRA (30 mumol/kg body wt) or vehicle for 5 d. The hepatic activity of PEMT increased 50% in both diabetic rat groups, whereas administration of ATRA was without effect. In diabetic rats, plasma total homocysteine decreased 30-35% in all treatment groups as compared with the control group. Thus, alterations in the activity of PEMT were not directly correlated to changes in homocysteine concentrations. Moreover, treatment of diabetic rats with insulin prevented the increase in PEMT activity and abundance. Because these observations support an increased need for SAM-dependent phosphatidylcholine synthesis, this may also indicate an increased choline requirement in diabetes.
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Affiliation(s)
- Cara S Hartz
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
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20
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Eilertsen KJ, Power RA, Harkins LL, Misica P. Targeting cellular memory to reprogram the epigenome, restore potential, and improve somatic cell nuclear transfer. Anim Reprod Sci 2006; 98:129-46. [PMID: 17166676 DOI: 10.1016/j.anireprosci.2006.10.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Successful cloning by somatic cell nuclear transfer (SCNT) is thought to require reprogramming of a somatic nucleus to a state of restored totipotentiality [Dean, W., Santos, F., Reik, W., 2003. Epigenetic programming in early mammalian development and following somatic cell nuclear transfer. Semin. Cell. Dev. Biol. 14, 93-100; Jouneau, A., Renard, J.P., 2003. Reprogramming in nuclear transfer. Curr. Opin. Genet. Dev. 13, 486-491; ]. Though SCNT-induced reprogramming is reminiscent of the reprogramming that occurs after fertilization, reprogramming a differentiated nucleus to an embryonic state is delayed and incomplete in comparison (for review, see ). This is likely due to the existence of an epigenetic-based cellular memory, or program, that serves to regulate global patterns of gene expression, and is the basis of a genome defense mechanism that silences viruses and transposons. The mechanisms of this memory include CpG methylation and modification of histones. Recent evidence by Feng et al. [Feng, Y.-Q., Desprat, R., Fu, H., Olivier, E., Lin, C.M., Lobell, A., Gowda, S.N., Aladjem, M.I., Bouhasira, E.E., 2006. DNA methylation supports intrinsic epigenetic memory in mammalian cells. PLOS Genet. 2, 0461-0470], using a transgenic experimental system, indicates that these marks may be acquired in more than one order and thus, silent heterochromatic structure can be initiated by either methylation of CpG dinucleotides or by histone modifications. In this system, however, CpG methylation appears to differ from histone modifications because it bestows a persistent epigenetic, or cellular, memory. In other words, CpG methylation can independently confer cellular memory, whereas histone modifications appear to be limited in this capacity. Therefore, in the context of genomic reprogramming induced by SCNT, efficient demethylation is likely a key (if not the only) rate-limiting step to improving the efficiency and outcomes of SCNT cloning. This review discusses the possibility of targeting cellular memory, and in particular inducing demethylation of a somatic nucleus prior to nuclear transfer, to enable reprogramming events typically carried out by oocyte factors and thereby improve developmental competence of SCNT-reconstructed embryos. Several recent published reviews of SCNT, cellular reprogramming and genomic demethylation served as valuable sources for the authors and are recommended as supplemental reading. These include the following: Bird, A., 2002. DNA methylation patterns and epigenetic memory. Gen. Dev. 16, 6-21; Grafi, G., 2004. How cells dedifferentiate: a lesson from plants. Dev. Biol. 268, 1-6; Latham, K.E., 2005. Early and delayed aspects of nuclear reprogramming during cloning. Biol. Cell 97, 119-132; Lyko, F., Brown, R., 2005. DNA methyltransferase inhibitors and the development of epigenetic cancer therapies. J.Natl. Cancer Inst. 97, 1498-1506; Morgan, H.D., Santos, F., Green, K., Dean, W., Reik, W., 2005. Epigenetic reprogramming in mammals. Hum. Mol. Gen. 14, R47-R58; Szyf, M., 2005. DNA methylation and demethylation as targets for anticancer therapy. Biochemistry 70, 533-549; Buszczak, M., Spradling, A.C., 2006. Searching chromatin for stem cell identity. Cell 125, 233-236; Gurdon, J.B., 2006. From nuclear transfer to nuclear reprogramming: the reversal of cell differentiation. Annu. Rev. Cell. Dev. Biol. 22, 1-22; Yoo, C.B., Jones, P.A., 2006. Epigenetic therapy of cancer: past, present and future. Nat. Rev. 5, 37-50.
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Affiliation(s)
- K J Eilertsen
- Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
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21
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Ulrey CL, Liu L, Andrews LG, Tollefsbol TO. The impact of metabolism on DNA methylation. Hum Mol Genet 2005; 14 Spec No 1:R139-47. [PMID: 15809266 DOI: 10.1093/hmg/ddi100] [Citation(s) in RCA: 205] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Methylation of genomic cytosines is one of the best characterized epigenetic mechanisms, and investigation of its relationship with other biochemical pathways represents a critical stage in the elucidation of biological information processing. The field also has immense potential for the development of medical treatments for any number of conditions ranging from aging to neurological disorders. The DNA methylation status of genes is responsible for many heritable traits and varies more or less independently of the genetic code. This variation is often a result of cellular environmental factors including metabolism. A key metabolite in this regard is homocysteine. Knowledge of homocysteine metabolism continues to be amassed, yet the part played by aberrant DNA methylation in homocysteine-related pathologies is often, at best, conjectural. In this analysis, we will review recent insights and attempt to speculate meaningfully concerning the dynamics of the methionine cycle in relation to DNA methylation and disease.
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Affiliation(s)
- Clayton L Ulrey
- Department of Biology, University of Alabama at Birmingham, 35294, USA
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22
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Tanghe KA, Garrow TA, Schalinske KL. Triiodothyronine treatment attenuates the induction of hepatic glycine N-methyltransferase by retinoic acid and elevates plasma homocysteine concentrations in rats. J Nutr 2004; 134:2913-8. [PMID: 15514252 DOI: 10.1093/jn/134.11.2913] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recent studies indicated that hormonal imbalances have a role in modulating the metabolism of methyl groups and homocysteine, interrelated pathways that when disrupted, are associated with a number of pathologies. Retinoic acid (RA) was shown to induce hepatic glycine N-methyltransferase (GNMT), a key regulatory protein in methyl group metabolism, and to reduce circulating homocysteine levels. Because thyroid status influences the hepatic folate-dependent one-carbon pool and retinoids can alter thyroid hormone levels, the aim of this study was to examine the interaction between retinoids and thyroid function. For hypothyroid studies, rats were administered 0.5 g/L propylthiouracil in the drinking water for 15 d, and RA [30 micromol/(kg . d)] for the final 5 d. For hyperthyroid studies, rats were treated with RA [30 micromol/(kg . d)] for 8 d and triiodothyronine [T(3); 50 microg/(100 g . d)] the last 4 d. T(3) treatment prevented the RA-mediated increase in GNMT activity. However, GNMT abundance remained elevated, indicating that GNMT regulation by T(3) in RA-treated rats may be, at least in part, at the post-translational level. In addition, T(3) treatment elevated plasma levels of homocysteine 177%, an elevation that was prevented by RA. T(3)-mediated hyperhomocysteinemia may be due to a 70% decrease in hepatic betaine-homocysteine S-methyltransferase, the enzyme that catalyzes folate-independent remethylation of homocysteine, whereas the RA-mediated stimulation of hepatic homocysteine remethylation by folate-dependent methionine synthase may contribute to lowering plasma homocysteine levels. These findings indicate that thyroid hormones, alone and in conjunction with RA, play an important role in the regulation of methyl group and homocysteine metabolism.
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Affiliation(s)
- Kelly A Tanghe
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
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23
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Nieman KM, Rowling MJ, Garrow TA, Schalinske KL. Modulation of methyl group metabolism by streptozotocin-induced diabetes and all-trans-retinoic acid. J Biol Chem 2004; 279:45708-12. [PMID: 15347642 DOI: 10.1074/jbc.m408664200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The hepatic enzyme glycine N-methyltransferase (GNMT) plays a major role in the control of methyl group and homocysteine metabolism. Because disruption of these vital pathways is associated with numerous pathologies, understanding GNMT control is important for evaluating methyl group regulation. Recently, gluconeogenic conditions have been shown to modulate homocysteine metabolism and treatment with glucocorticoids and/or all-trans-retinoic acid (RA)-induced active GNMT protein, thereby leading to methyl group loss. This study was conducted to determine the effect of diabetes, alone and in combination with RA, on GNMT regulation. Diabetes and RA increased GNMT activity 87 and 148%, respectively. Moreover, the induction of GNMT activity by diabetes and RA was reflected in its abundance. Cell culture studies demonstrated that pretreatment with insulin prevented GNMT induction by both RA and dexamethasone. There was a significant decline in homocysteine concentrations in diabetic rats, owing in part to a 38% increase in the abundance of the transsulfuration enzyme cystathionine beta-synthase; treatment of diabetic rats with RA prevented cystathionine beta-synthase induction. A diabetic state also increased the activity of the folate-independent homocysteine remethylation enzyme betaine-homocysteine S-methyltransferase, whereas the activity of the folate-dependent enzyme methionine synthase was diminished 52%. In contrast, RA treatment attenuated the streptozotocin-mediated increase in betaine-homocysteine S-methyltransferase, whereas methionine synthase activity remained diminished. These results indicate that both a diabetic condition and RA treatment have marked effects on the metabolism of methyl groups and homocysteine, a finding that may have significant implications for diabetics and their potential sensitivity to retinoids.
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Affiliation(s)
- Kristin M Nieman
- Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa 50011, USA
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24
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Rowling MJ, Schalinske KL. Retinoic acid and glucocorticoid treatment induce hepatic glycine N-methyltransferase and lower plasma homocysteine concentrations in rats and rat hepatoma cells. J Nutr 2004; 133:3392-8. [PMID: 14608049 DOI: 10.1093/jn/133.11.3392] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Perturbation of folate and methyl group metabolism is associated with a number of pathological conditions, including cardiovascular disease and neoplastic development. Glycine N-methyltransferase (GNMT) is a key protein that functions to regulate the supply and utilization of methyl groups for S-adenosylmethionine (SAM)-dependent transmethylation reactions. Factors or conditions that have the ability to regulate GNMT and the generation of homocysteine, a product of transmethylation, have important implications in the potential perturbation of methyl group metabolism. We showed that retinoid compounds induce active hepatic GNMT, resulting in compromised transmethylation processes. Because retinoids can stimulate gluconeogenesis, a condition known to alter methyl group and homocysteine metabolism, the current study was undertaken to determine the relationship between all-trans-retinoic acid (RA) and gluconeogenic hormones on these metabolic pathways. Intact adrenal function was not required for RA to induce and activate hepatic GNMT; however, treatment of rats with dexamethasone (DEX) was as effective as RA in inducing GNMT in rat liver. The marked increase in plasma total homocysteine levels observed in adrenalectomized rats was reduced to normal levels by treatment with either RA or DEX, indicating that the transsulfuration and/or remethylation pathways may be enhanced. Moreover, coadministration of RA and DEX had an additive effect on GNMT induction. Similar findings were also observed in a rat hepatoma cell culture model using H4IIE cells. Taken together, these results demonstrate that both RA and DEX independently induce GNMT, thereby having substantial implications for the potential interaction of retinoid administration with diabetes.
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Affiliation(s)
- Matthew J Rowling
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
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25
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Ozias MK, Schalinske KL. All-trans-retinoic acid rapidly induces glycine N-methyltransferase in a dose-dependent manner and reduces circulating methionine and homocysteine levels in rats. J Nutr 2004; 133:4090-4. [PMID: 14652353 DOI: 10.1093/jn/133.12.4090] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Glycine N-methyltransferase (GNMT) regulates the methyl group supply for S-adenosylmethionine-dependent transmethylation reactions. Retinoids have been shown to perturb methyl group metabolism by increasing the abundance and activity of GNMT, thereby leading to the loss of methyl groups. Previous studies used pharmacologic doses (30 micro mol/kg body weight) of various retinoids administered daily for a total of 10 d. Here, we examined the dose- and time-dependent relationships between all-trans-retinoic acid (ATRA) administration and induction of GNMT, as well as determining additional indices of methyl group and folate metabolism. For the dose-response study, rats were administered 0, 1, 5, 10, 15 or 30 micro mol ATRA/kg body weight for 10 d. For the time-course study, rats were given 30 micromol ATRA/kg body weight for 0, 1, 2, 4, or 8 d. A significant increase (105%) in GNMT activity was observed with doses as low as 5 micromol/kg body weight, whereas maximal induction (231%) of GNMT activity was achieved at 30 micromol/kg body weight. Induction of hepatic GNMT by ATRA was rapid, exhibiting a 31% increase after a single dose (1 d) and achieving maximal induction (95%) after 4 d. Plasma methionine and homocysteine concentrations were decreased 42 and 53%, respectively, in ATRA-treated rats compared with controls. In support of this finding, the hepatic activity of methionine synthase, the folate-dependent enzyme required for homocysteine remethylation, was elevated 40% in ATRA-treated rats. This work demonstrates that ATRA administration exerts a rapid effect on hepatic methyl group, folate and homocysteine metabolism at doses that are within the therapeutic range used by humans.
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Affiliation(s)
- Marlies K Ozias
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
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26
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Rowling MJ, McMullen MH, Chipman DC, Schalinske KL. Hepatic glycine N-methyltransferase is up-regulated by excess dietary methionine in rats. J Nutr 2002; 132:2545-50. [PMID: 12221207 DOI: 10.1093/jn/132.9.2545] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Glycine N-methyltransferase (GNMT) regulates S-adenosylmethionine (SAM) levels and the ratio of SAM:S-adenosylhomocysteine (SAH). In liver, methionine availability, both from the diet and via the folate-dependent one-carbon pool, modulates GNMT activity to maintain an optimal SAM:SAH ratio. The regulation of GNMT activity is accomplished via posttranslational and allosteric mechanisms. We more closely examined GNMT regulation in various tissues as a function of excess dietary methyl groups. Sprague Dawley rats were fed either a control diet (10% casein plus 0.3% L-methionine) or the control diet supplemented with graded levels (0.5-2%) of L-methionine. Pair-fed control groups of rats were included due to the toxicity associated with high methionine consumption. As expected, the hepatic activity of GNMT was significantly elevated in a dose-dependent fashion after 10 d of feeding the diets containing excess methionine. Moreover, the abundance of hepatic GNMT protein was similarly increased. The kidney had a significant increase in GNMT as a function of dietary methionine, but to a much lesser extent than in the liver. For pancreatic tissue, neither the activity of GNMT nor the abundance of the protein was responsive to excess dietary methionine. These data suggest that additional mechanisms contribute to regulation of GNMT such that synthesis of the protein is greater than its degradation. In addition, methionine-induced regulation of GNMT is dose dependent and appears to be tissue specific, the latter suggesting that the role it plays in the kidney and pancreas may in part differ from its hepatic function.
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Affiliation(s)
- Matthew J Rowling
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
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