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Mirzadeh Azad F, Struys EA, Wingert V, Hannibal L, Mills K, Jansen JH, Longley DB, Stunnenberg HG, Atlasi Y. Spic regulates one-carbon metabolism and histone methylation in ground-state pluripotency. SCIENCE ADVANCES 2023; 9:eadg7997. [PMID: 37595034 DOI: 10.1126/sciadv.adg7997] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 07/20/2023] [Indexed: 08/20/2023]
Abstract
Understanding mechanisms of epigenetic regulation in embryonic stem cells (ESCs) is of fundamental importance for stem cell and developmental biology. Here, we identify Spic, a member of the ETS family of transcription factors (TFs), as a marker of ground state pluripotency. We show that Spic is rapidly induced in ground state ESCs and in response to extracellular signal-regulated kinase (ERK) inhibition. We find that SPIC binds to enhancer elements and stabilizes NANOG binding to chromatin, particularly at genes involved in choline/one-carbon (1C) metabolism such as Bhmt, Bhmt2, and Dmgdh. Gain-of-function and loss-of-function experiments revealed that Spic controls 1C metabolism and the flux of S-adenosyl methionine to S-adenosyl-L-homocysteine (SAM-to-SAH), thereby, modulating the levels of H3R17me2 and H3K4me3 histone marks in ESCs. Our findings highlight betaine-dependent 1C metabolism as a hallmark of ground state pluripotency primarily activated by SPIC. These findings underscore the role of uncharacterized auxiliary TFs in linking cellular metabolism to epigenetic regulation in ESCs.
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Affiliation(s)
- Fatemeh Mirzadeh Azad
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| | - Eduard A Struys
- Department of Clinical Chemistry, Amsterdam University Medical Center, Amsterdam, Netherlands
| | - Victoria Wingert
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Ken Mills
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| | - Joop H Jansen
- Department of Laboratory Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands
| | - Daniel B Longley
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| | - Hendrik G Stunnenberg
- Department of Molecular Biology, Faculty of Science, Radboud University, Nijmegen, Netherlands
- Princess Maxima Centre for Pediatric Oncology, Utrecht, Netherlands
| | - Yaser Atlasi
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
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2
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Bergant V, Yamada S, Grass V, Tsukamoto Y, Lavacca T, Krey K, Mühlhofer MT, Wittmann S, Ensser A, Herrmann A, Vom Hemdt A, Tomita Y, Matsuyama S, Hirokawa T, Huang Y, Piras A, Jakwerth CA, Oelsner M, Thieme S, Graf A, Krebs S, Blum H, Kümmerer BM, Stukalov A, Schmidt-Weber CB, Igarashi M, Gramberg T, Pichlmair A, Kato H. Attenuation of SARS-CoV-2 replication and associated inflammation by concomitant targeting of viral and host cap 2'-O-ribose methyltransferases. EMBO J 2022; 41:e111608. [PMID: 35833542 PMCID: PMC9350232 DOI: 10.15252/embj.2022111608] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 06/23/2022] [Accepted: 06/27/2022] [Indexed: 12/12/2022] Open
Abstract
The SARS‐CoV‐2 infection cycle is a multistage process that relies on functional interactions between the host and the pathogen. Here, we repurposed antiviral drugs against both viral and host enzymes to pharmaceutically block methylation of the viral RNA 2'‐O‐ribose cap needed for viral immune escape. We find that the host cap 2'‐O‐ribose methyltransferase MTr1 can compensate for loss of viral NSP16 methyltransferase in facilitating virus replication. Concomitant inhibition of MTr1 and NSP16 efficiently suppresses SARS‐CoV‐2 replication. Using in silico target‐based drug screening, we identify a bispecific MTr1/NSP16 inhibitor with anti‐SARS‐CoV‐2 activity in vitro and in vivo but with unfavorable side effects. We further show antiviral activity of inhibitors that target independent stages of the host SAM cycle providing the methyltransferase co‐substrate. In particular, the adenosylhomocysteinase (AHCY) inhibitor DZNep is antiviral in in vitro, in ex vivo, and in a mouse infection model and synergizes with existing COVID‐19 treatments. Moreover, DZNep exhibits a strong immunomodulatory effect curbing infection‐induced hyperinflammation and reduces lung fibrosis markers ex vivo. Thus, multispecific and metabolic MTase inhibitors constitute yet unexplored treatment options against COVID‐19.
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Affiliation(s)
- Valter Bergant
- Institute of Virology, School of Medicine, Technical University of Munich (TUM), Munich, Germany
| | - Shintaro Yamada
- Institute of Cardiovascular Immunology, University Hospital Bonn (UKB), Bonn, Germany
| | - Vincent Grass
- Institute of Virology, School of Medicine, Technical University of Munich (TUM), Munich, Germany
| | - Yuta Tsukamoto
- Institute of Cardiovascular Immunology, University Hospital Bonn (UKB), Bonn, Germany
| | - Teresa Lavacca
- Institute of Virology, School of Medicine, Technical University of Munich (TUM), Munich, Germany
| | - Karsten Krey
- Institute of Virology, School of Medicine, Technical University of Munich (TUM), Munich, Germany
| | - Maria-Teresa Mühlhofer
- Institute of Virology, School of Medicine, Technical University of Munich (TUM), Munich, Germany
| | - Sabine Wittmann
- Institute of Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Armin Ensser
- Institute of Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Alexandra Herrmann
- Institute of Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Anja Vom Hemdt
- Institute of Virology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Yuriko Tomita
- Department of Virology III, National Institute of Infectious Diseases (NIID), Tokyo, Japan
| | - Shutoku Matsuyama
- Department of Virology III, National Institute of Infectious Diseases (NIID), Tokyo, Japan
| | - Takatsugu Hirokawa
- Transborder Medical Research Center, University of Tsukuba, Tsukuba, Japan.,Division of Biomedical Science, University of Tsukuba, Tsukuba, Japan.,Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Yiqi Huang
- Institute of Virology, School of Medicine, Technical University of Munich (TUM), Munich, Germany
| | - Antonio Piras
- Institute of Virology, School of Medicine, Technical University of Munich (TUM), Munich, Germany
| | - Constanze A Jakwerth
- Center for Allergy & Environment (ZAUM), Technical University of Munich (TUM) and Helmholtz Center Munich, German Research Center for Environmental Health, Member of the German Center for Lung Research (DZL), CPC-M, Munich, Germany
| | - Madlen Oelsner
- Center for Allergy & Environment (ZAUM), Technical University of Munich (TUM) and Helmholtz Center Munich, German Research Center for Environmental Health, Member of the German Center for Lung Research (DZL), CPC-M, Munich, Germany
| | - Susanne Thieme
- Laboratory for functional genome analysis (LAFUGA), Gene Centre, Ludwig Maximilian University of Munich (LMU), Munich, Germany
| | - Alexander Graf
- Laboratory for functional genome analysis (LAFUGA), Gene Centre, Ludwig Maximilian University of Munich (LMU), Munich, Germany
| | - Stefan Krebs
- Laboratory for functional genome analysis (LAFUGA), Gene Centre, Ludwig Maximilian University of Munich (LMU), Munich, Germany
| | - Helmut Blum
- Laboratory for functional genome analysis (LAFUGA), Gene Centre, Ludwig Maximilian University of Munich (LMU), Munich, Germany
| | - Beate M Kümmerer
- Institute of Virology, Medical Faculty, University of Bonn, Bonn, Germany.,German Centre for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Alexey Stukalov
- Institute of Virology, School of Medicine, Technical University of Munich (TUM), Munich, Germany
| | - Carsten B Schmidt-Weber
- Center for Allergy & Environment (ZAUM), Technical University of Munich (TUM) and Helmholtz Center Munich, German Research Center for Environmental Health, Member of the German Center for Lung Research (DZL), CPC-M, Munich, Germany
| | - Manabu Igarashi
- International Collaboration Unit, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido, Japan.,Division of Global Epidemiology, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Thomas Gramberg
- Institute of Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Andreas Pichlmair
- Institute of Virology, School of Medicine, Technical University of Munich (TUM), Munich, Germany.,German Center for Infection Research (DZIF), Munich partner site, Germany
| | - Hiroki Kato
- Institute of Cardiovascular Immunology, University Hospital Bonn (UKB), Bonn, Germany
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3
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Long-term effect of parental selenium supplementation on the one-carbon metabolism in rainbow trout ( Oncorhynchus mykiss) fry exposed to hypoxic stress. Br J Nutr 2021; 127:23-34. [PMID: 33658100 DOI: 10.1017/s000711452100074x] [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] [Indexed: 01/24/2023]
Abstract
This study evaluated how different forms of selenium (Se) supplementation into rainbow trout broodstock diets modified the one-carbon metabolism of the progeny after the beginning of exogenous feeding and followed by hypoxia challenge. The progeny of three groups of rainbow trout broodstock fed either a control diet (Se level: 0·3 µg/g) or a diet supplemented with inorganic sodium selenite (Se level: 0·6 µg/g) or organic hydroxy-selenomethionine (Se level: 0·6 µg/g) was cross-fed with diets of similar Se composition for 11 weeks. Offspring were sampled either before or after being subjected to an acute hypoxic stress (1·7 mg/l dissolved oxygen) for 30 min. In normoxic fry, parental Se supplementation allowed higher glutathione levels compared with fry originating from parents fed the control diet. Parental hydroxy-selenomethionine treatment also increased cysteine and cysteinyl-glycine concentrations in fry. Dietary Se supplementation decreased glutamate-cysteine ligase (cgl) mRNA levels. Hydroxy-selenomethionine feeding also lowered the levels of some essential free amino acids in muscle tissue. Supplementation of organic Se to parents and fry reduced betaine-homocysteine S-methyltransferase (bhmt) expression in fry. The hypoxic stress decreased whole-body homocysteine, cysteine, cysteinyl-glycine and glutathione levels. Together with the higher mRNA levels of cystathionine beta-synthase (cbs), a transsulphuration enzyme, this suggests that under hypoxia, glutathione synthesis through transsulphuration might have been impaired by depletion of a glutathione precursor. In stressed fry, S-adenosylmethionine levels were significantly decreased, but S-adenosylhomocysteine remained stable. Decreased bhmt and adenosylmethionine decarboxylase 1a (amd1a) mRNA levels in stressed fry suggest a nutritional programming by parental Se also on methionine metabolism of rainbow trout.
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4
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Bucktrout RE, Ma N, Aboragah A, Alharthi AS, Liang Y, Lopreiato V, Lopes MG, Trevisi E, Alhidary IA, Fernandez C, Loor JJ. One-carbon, carnitine, and glutathione metabolism-related biomarkers in peripartal Holstein cows are altered by prepartal body condition. J Dairy Sci 2021; 104:3403-3417. [PMID: 33455750 DOI: 10.3168/jds.2020-19402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 10/15/2020] [Indexed: 12/13/2022]
Abstract
We investigated how prepartal body condition score (BCS) alters key hepatic enzymes associated with 1-carbon, carnitine, and glutathione metabolism and the related biomarkers in liver tissue and plasma of periparturient dairy cows. Twenty-six multiparous Holstein dairy cows were retrospectively selected according to BCS at 4 wk prepartum and divided into high (HighBCS, BCS ≥ 3.50) and normal (NormBCS, BCS ≤ 3.25) BCS groups (n = 13 each). Blood plasma samples were obtained at -30, -10, 7, 15, and 30 d relative to calving. Liver tissue biopsies were performed at -15, 7, and 30 d relative to calving, and samples were used to assess protein abundance via Western blot assay. Cows in the HighBCS group lost ∼1 unit of BCS between -4 and 4 wk around calving, while NormBCS cows lost ∼0.5 unit in the same period. Prepartal dry matter intake (DMI, kg/d) did not differ between groups. Compared with NormBCS cows, HighBCS cows had higher postpartal DMI and milk yield (+5.34 kg/d). In addition, greater overall plasma concentrations of fatty acids and activity of the neutrophil-enriched enzyme myeloperoxidase were observed in HighBCS compared with NormBCS cows. Despite similar reactive oxygen metabolite concentrations in both groups at 30 d, HighBCS cows had lower overall concentrations of β-carotene and tocopherol, explaining the lower (BCS × Time) antioxidant capacity (ferric reducing ability of plasma). The HighBCS cows also had greater liver malondialdehyde concentrations and superoxide dismutase activity at 30 d. Overall, compared with NormBCS cows, HighBCS cows had lower hepatic protein abundance of the 1-carbon metabolism enzymes cystathionine-β-synthase, betaine-homocysteine methyltransferase, and methionine adenosyltransferase 1 A (MAT1A), as well as the glutathione metabolism-related enzymes glutathione S-transferase α 4 and glutathione peroxidase 3 (GPX3). A lower protein abundance of glutathione S-transferase mu 1 (GSTM1) at -15 and 7 d was also observed. Regardless of BCS, cows had increased abundance of GSTM1 and GPX3 between -15 and 7 d around calving. A marked decrease of gamma-butyrobetaine dioxygenase 1 from -10 to 7 d in HighBCS compared with NormBCS cows suggested a decrease in de novo carnitine synthesis that was partly explained by the lower abundance of MAT1A. Overall, data suggest biologic links between BCS before calving, milk yield, immune response, and hepatic reactions encompassing 1-carbon metabolism, carnitine, and antioxidant synthesis.
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Affiliation(s)
- R E Bucktrout
- Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801
| | - N Ma
- Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801; College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - A Aboragah
- Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801
| | - A S Alharthi
- Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Y Liang
- Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801
| | - V Lopreiato
- Department of Animal Sciences, Food and Nutrition, Faculty of Agriculture, Food and Environmental Science, Università Cattolica del Sacro Cuore, 29122 Piacenza, Italy
| | - M G Lopes
- Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801; NUPEEC (Núcleo de Pesquisa, Ensino e Extensão em Pecuária), Departamento de Clínicas Veterinária, Programa de Pós-Graduação em Biotecnologia, Universidade Federal de Pelotas, 96010-610, Pelotas, RS, Brazil
| | - E Trevisi
- Department of Animal Sciences, Food and Nutrition, Faculty of Agriculture, Food and Environmental Science, Università Cattolica del Sacro Cuore, 29122 Piacenza, Italy
| | - I A Alhidary
- Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - C Fernandez
- Animal Science Department, Universitàt Politècnica de Valencia, 46022 Valencia, Spain
| | - J J Loor
- Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801.
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5
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Saande CJ, Pritchard SK, Worrall DM, Snavely SE, Nass CA, Neuman JC, Luchtel RA, Dobiszewski S, Miller JW, Vailati-Riboni M, Loor JJ, Schalinske KL. Dietary Egg Protein Prevents Hyperhomocysteinemia via Upregulation of Hepatic Betaine-Homocysteine S-Methyltransferase Activity in Folate-Restricted Rats. J Nutr 2019; 149:1369-1376. [PMID: 31111947 DOI: 10.1093/jn/nxz069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 02/19/2019] [Accepted: 03/20/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Hyperhomocysteinemia is associated with increased cardiovascular disease risk. Whole eggs contain several nutrients known to affect homocysteine regulation, including sulfur amino acids, choline, and B vitamins. OBJECTIVE The aim of this study was to determine the effect of whole eggs and egg components (i.e., egg protein and choline) with respect to 1) homocysteine balance and 2) the hepatic expression and activity of betaine-homocysteine S-methyltransferase (BHMT) and cystathionine β-synthase (CBS) in a folate-restricted (FR) rat model of hyperhomocysteinemia. METHODS Male Sprague Dawley rats (n = 48; 6 wk of age) were randomly assigned to a casein-based diet (C; n = 12), a casein-based diet supplemented with choline (C + Cho; 1.3%, wt:wt; n = 12), an egg protein-based diet (EP; n = 12), or a whole egg-based diet (WE; n = 12). At week 2, half of the rats in each of the 4 dietary groups were provided an FR (0 g folic acid/kg) diet and half continued on the folate-sufficient (FS; 0.2 g folic acid/kg) diet for an additional 6 wk. All diets contained 20% (wt:wt) total protein. Serum homocysteine was measured by HPLC and BHMT and CBS expression and activity were evaluated using real-time quantitative polymerase chain reaction, Western blot, and enzyme activity. A 2-factor ANOVA was used for statistical comparisons. RESULTS Rats fed FR-C exhibited a 53% increase in circulating homocysteine concentrations compared with rats fed FS-C (P < 0.001). In contrast, serum homocysteine did not differ between rats fed FS-C and FR-EP (P = 0.078). Hepatic BHMT activity was increased by 45% and 40% by the EP (P < 0.001) and WE (P = 0.002) diets compared with the C diets, respectively. CONCLUSIONS Dietary intervention with egg protein prevented elevated circulating homocysteine concentrations in a rat model of hyperhomocysteinemia, due in part to upregulation of hepatic BHMT. These data may support the inclusion of egg protein for dietary recommendations targeting hyperhomocysteinemia prevention.
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Affiliation(s)
- Cassondra J Saande
- Department of Food Science and Human Nutrition.,Interdepartmental Graduate Program in Nutritional Sciences, Iowa State University, Ames, IA
| | - Samantha K Pritchard
- Department of Food Science and Human Nutrition.,Interdepartmental Graduate Program in Nutritional Sciences, Iowa State University, Ames, IA
| | | | | | | | - Joshua C Neuman
- Department of Food Science and Human Nutrition.,Interdepartmental Graduate Program in Nutritional Sciences, Iowa State University, Ames, IA
| | - Rebecca A Luchtel
- Department of Food Science and Human Nutrition.,Interdepartmental Graduate Program in Nutritional Sciences, Iowa State University, Ames, IA
| | - Sarah Dobiszewski
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ
| | - Joshua W Miller
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ
| | - Mario Vailati-Riboni
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL
| | - Juan J Loor
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL
| | - Kevin L Schalinske
- Department of Food Science and Human Nutrition.,Interdepartmental Graduate Program in Nutritional Sciences, Iowa State University, Ames, IA
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Colomina JM, Cavallé-Busquets P, Fernàndez-Roig S, Solé-Navais P, Fernandez-Ballart JD, Ballesteros M, Ueland PM, Meyer K, Murphy MM. Maternal Folate Status and the BHMT c.716G>A Polymorphism Affect the Betaine Dimethylglycine Pathway during Pregnancy. Nutrients 2016; 8:nu8100621. [PMID: 27735840 PMCID: PMC5084009 DOI: 10.3390/nu8100621] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 09/20/2016] [Accepted: 09/27/2016] [Indexed: 12/31/2022] Open
Abstract
The effect of the betaine: homocysteine methyltransferase BHMT c.716G>A (G: guanosine; A: adenosine) single nucleotide polymorphism (SNP) on the BHMT pathway is unknown during pregnancy. We hypothesised that it impairs betaine to dimethylglycine conversion and that folate status modifies its effect. We studied 612 women from the Reus Tarragona Birth Cohort from ≤12 gestational weeks (GW) throughout pregnancy. The frequency of the variant BHMT c.716A allele was 30.8% (95% confidence interval (CI): 28.3, 33.5). In participants with normal-high plasma folate status (>13.4 nmol/L), least square geometric mean [95% CI] plasma dimethylglycine (pDMG, µmol/L) was lower in the GA (2.35 [2.23, 2.47]) versus GG (2.58 [2.46, 2.70]) genotype at ≤12 GW (p < 0.05) and in the GA (2.08 [1.97, 2.19]) and AA (1.94 [1.75, 2.16]) versus GG (2.29 [2.18, 2.40]) genotypes at 15 GW (p < 0.05). No differences in pDMG between genotypes were observed in participants with possible folate deficiency (≤13.4 nmol/L) (p for interactions at ≤12 GW: 0.023 and 15 GW: 0.038). PDMG was lower in participants with the AA versus GG genotype at 34 GW (2.01 [1.79, 2.25] versus 2.44 [2.16, 2.76] and at labour, 2.51 [2.39, 2.64] versus 3.00 [2.84, 3.18], (p < 0.01)). Possible deficiency compared to normal-high folate status was associated with higher pDMG in multiple linear regression analysis (β coefficients [SEM] ranging from 0.07 [0.04], p < 0.05 to 0.20 [0.04], p < 0.001 in models from early and mid-late pregnancy) and the AA compared to GG genotype was associated with lower pDMG (β coefficients [SEM] ranging from −0.11 [0.06], p = 0.055 to −0.23 [0.06], p < 0.001). Conclusion: During pregnancy, the BHMT pathway is affected by folate status and by the variant BHMT c.716A allele.
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Affiliation(s)
- Jose M Colomina
- Area of Preventive Medicine and Public Health, Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili, IISPV, C/Sant Llorenç 21, Reus 43201, Spain.
- Ciberobn Fisiopatología de la Obesidad y Nutrición (CB06/03), Instituto Carlos III, Madrid 28029, Spain.
| | - Pere Cavallé-Busquets
- Ciberobn Fisiopatología de la Obesidad y Nutrición (CB06/03), Instituto Carlos III, Madrid 28029, Spain.
- Area of Obstetrics and Gynaecology, Hospital Universitari Sant Joan, Reus and Universitat Rovira i Virgili, Reus 43204, Spain.
| | - Sílvia Fernàndez-Roig
- Area of Preventive Medicine and Public Health, Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili, IISPV, C/Sant Llorenç 21, Reus 43201, Spain.
- Ciberobn Fisiopatología de la Obesidad y Nutrición (CB06/03), Instituto Carlos III, Madrid 28029, Spain.
| | - Pol Solé-Navais
- Area of Preventive Medicine and Public Health, Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili, IISPV, C/Sant Llorenç 21, Reus 43201, Spain.
- Ciberobn Fisiopatología de la Obesidad y Nutrición (CB06/03), Instituto Carlos III, Madrid 28029, Spain.
| | - Joan D Fernandez-Ballart
- Area of Preventive Medicine and Public Health, Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili, IISPV, C/Sant Llorenç 21, Reus 43201, Spain.
- Ciberobn Fisiopatología de la Obesidad y Nutrición (CB06/03), Instituto Carlos III, Madrid 28029, Spain.
| | - Mónica Ballesteros
- Area of Obstetrics and Gynaecology, Hospital Universitari Joan XXIII, Tarragona and Universitat Rovira i Virgili, Tarragona 43005, Spain.
| | - Per M Ueland
- Section for Pharmacology, Department of Internal Medicine, University of Bergen, Bergen N-5020, Norway.
| | - Klaus Meyer
- Bevital A/S, Laboratory building, 9th floor, Bergen N-5021, Norway.
| | - Michelle M Murphy
- Area of Preventive Medicine and Public Health, Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili, IISPV, C/Sant Llorenç 21, Reus 43201, Spain.
- Ciberobn Fisiopatología de la Obesidad y Nutrición (CB06/03), Instituto Carlos III, Madrid 28029, Spain.
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7
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Creatine supplementation prevents hyperhomocysteinemia, oxidative stress and cancer-induced cachexia progression in Walker-256 tumor-bearing rats. Amino Acids 2016; 48:2015-24. [DOI: 10.1007/s00726-016-2172-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 01/06/2016] [Indexed: 12/16/2022]
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8
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Kwak HC, Kim YM, Oh SJ, Kim SK. Sulfur amino acid metabolism in Zucker diabetic fatty rats. Biochem Pharmacol 2015; 96:256-66. [PMID: 26047850 DOI: 10.1016/j.bcp.2015.05.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 05/27/2015] [Indexed: 10/23/2022]
Abstract
The present study was aimed to investigate the metabolomics of sulfur amino acids in Zucker diabetic fatty (ZDF) rats, an obese type 2 diabetic animal model. Plasma levels of total cysteine, homocysteine and methionine, but not glutathione (GSH) were markedly decreased in ZDF rats. Hepatic methionine, homocysteine, cysteine, betaine, taurine, spermidine and spermine were also decreased. There are no significant difference in hepatic S-adenosylmethionine, S-adenosylhomocysteine, GSH, GSH disulfide, hypotaurine and putrescine between control and ZDF rats. Hepatic SAH hydrolase, betaine-homocysteine methyltransferase and methylene tetrahydrofolate reductase were up-regulated while activities of gamma-glutamylcysteine ligase and methionine synthase were decreased. The area under the curve (AUC) of methionine and methionine-d4 was not significantly different in control and ZDF rats treated with a mixture of methionine (60mg/kg) and methionine-d4 (20mg/kg). Moreover, the AUC of the increase in plasma total homocysteine was comparable between two groups, although the homocysteine concentration curve was shifted leftward in ZDF rats, suggesting that the plasma total homocysteine after the methionine loading was rapidly increased and normalized in ZDF rats. These results show that the AUC of plasma homocysteine is not responsive to the up-regulation of hepatic BHMT in ZDF rats. The present study suggests that the decrease in hepatic methionine may be responsible for the decreases in its metabolites, such as homocysteine, cysteine, and taurine in liver and consequently decreased plasma homocysteine levels.
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Affiliation(s)
- Hui Chan Kwak
- College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, Republic of Korea
| | - Young-Mi Kim
- College of Pharmacy, Hanyang University, Ansan, Gyeonggido 426-791, Republic of Korea
| | - Soo Jin Oh
- Bio-Evaluation Center, KRIBB, Ochang, Chungbuk, Republic of Korea
| | - Sang Kyum Kim
- College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, Republic of Korea.
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Deminice R, de Castro GSF, Francisco LV, da Silva LECM, Cardoso JFR, Frajacomo FTT, Teodoro BG, Dos Reis Silveira L, Jordao AA. Creatine supplementation prevents fatty liver in rats fed choline-deficient diet: a burden of one-carbon and fatty acid metabolism. J Nutr Biochem 2015; 26:391-7. [PMID: 25649792 DOI: 10.1016/j.jnutbio.2014.11.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 11/05/2014] [Accepted: 11/19/2014] [Indexed: 02/06/2023]
Abstract
AIM To examine the effects of creatine (Cr) supplementation on liver fat accumulation in rats fed a choline-deficient diet. METHODS Twenty-four rats were divided into 3 groups of 8 based on 4 weeks of feeding an AIN-93 control diet (C), a choline-deficient diet (CDD) or a CDD supplemented with 2% Cr. The CDD diet was AIN-93 without choline. RESULTS The CDD significantly increased plasma homocysteine and TNFα concentration, as well as ALT activity. In liver, the CDD enhanced concentrations of total fat (55%), cholesterol (25%), triglycerides (87%), MDA (30%), TNFα (241%) and decreased SAM concentrations (25%) and the SAM/SAH ratio (33%). Cr supplementation prevented all these metabolic changes, except for hepatic SAM and the SAM/SAH ratio. However, no changes in PEMT gene expression or liver phosphatidylcholine levels were observed among the three experimental groups, and there were no changes in hepatic triglyceride transfer protein (MTP) mRNA level. On the contrary, Cr supplementation normalized expression of the transcription factors PPARα and PPARγ that were altered by the CDD. Further, the downstream targets and fatty acids metabolism genes, UCP2, LCAD and CPT1a, were also normalized in the Cr group as compared to CDD-fed rats. CONCLUSION Cr supplementation prevented fat liver accumulation and hepatic injures in rats fed with a CDD for 4 weeks. Our results demonstrated that one-carbon metabolism may have a small role in mitigating hepatic fat accumulation by Cr supplementation. The modulation of key genes related to fatty acid oxidation pathway suggests a new mechanism by which Cr prevents liver fat accumulation.
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Affiliation(s)
- Rafael Deminice
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil; Department of Physical Education, Faculty of Physical Education and Sport, State University of Londrina. Rodovia Celso Garcia Cid
- Pr 445 Km 380
- Campus Universitário, Londrina, Paraná, Brazil.
| | - Gabriela Salim Ferreira de Castro
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Lucas Vieira Francisco
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Lilian Eslaine Costa Mendes da Silva
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - João Felipe Rito Cardoso
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Fernando Tadeu Trevisan Frajacomo
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Bruno Gonzaga Teodoro
- Department of Biochesmtry and Imunology, Faculty of Medicine of Ribeirão Preto Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Leonardo Dos Reis Silveira
- School of Physical Education of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil; Department of Biochesmtry and Imunology, Faculty of Medicine of Ribeirão Preto Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Alceu Afonso Jordao
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
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Costa IR, Thompson JD, Ortega JM, Prosdocimi F. Metazoan remaining genes for essential amino acid biosynthesis: sequence conservation and evolutionary analyses. Nutrients 2014; 7:1-16. [PMID: 25545100 PMCID: PMC4303824 DOI: 10.3390/nu7010001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 11/25/2014] [Indexed: 11/16/2022] Open
Abstract
Essential amino acids (EAA) consist of a group of nine amino acids that animals are unable to synthesize via de novo pathways. Recently, it has been found that most metazoans lack the same set of enzymes responsible for the de novo EAA biosynthesis. Here we investigate the sequence conservation and evolution of all the metazoan remaining genes for EAA pathways. Initially, the set of all 49 enzymes responsible for the EAA de novo biosynthesis in yeast was retrieved. These enzymes were used as BLAST queries to search for similar sequences in a database containing 10 complete metazoan genomes. Eight enzymes typically attributed to EAA pathways were found to be ubiquitous in metazoan genomes, suggesting a conserved functional role. In this study, we address the question of how these genes evolved after losing their pathway partners. To do this, we compared metazoan genes with their fungal and plant orthologs. Using phylogenetic analysis with maximum likelihood, we found that acetolactate synthase (ALS) and betaine-homocysteine S-methyltransferase (BHMT) diverged from the expected Tree of Life (ToL) relationships. High sequence conservation in the paraphyletic group Plant-Fungi was identified for these two genes using a newly developed Python algorithm. Selective pressure analysis of ALS and BHMT protein sequences showed higher non-synonymous mutation ratios in comparisons between metazoans/fungi and metazoans/plants, supporting the hypothesis that these two genes have undergone non-ToL evolution in animals.
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Affiliation(s)
- Igor R Costa
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil.
| | - Julie D Thompson
- Department of Computer Science Research, ICube Laboratoire des sciences de l'ingénieur, de l'informatique et de l'imagerie, CNRS/Université de Strasbourg, 11 rue Humann, Strasbourg F-67000, France.
| | - José Miguel Ortega
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil.
| | - Francisco Prosdocimi
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil.
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Deminice R, Rosa FT, da Silva LECM, Jordao AA. Taurine supplementation does not decrease homocysteine levels and liver injury induced by a choline-deficient diet. Life Sci 2014; 105:43-7. [PMID: 24769283 DOI: 10.1016/j.lfs.2014.04.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 03/20/2014] [Accepted: 04/11/2014] [Indexed: 10/25/2022]
Abstract
AIMS The aim of this study is to examine the effects of taurine supplementation on homocysteine (Hcy) metabolism and liver injury in rats fed a choline-deficient diet. MAIN METHODS Thirty rats were divided into three groups (n=10), to receive one of the following diets for 4 weeks: control diet (C), choline-deficient diet (CDD), or choline-deficient diet supplemented with taurine (CDDT). The CDD and the CDDT consisted of AIN-93 without the recommended choline content of 2.5%, and the CDDT was supplemented by the addition of 2.5% taurine. KEY FINDINGS Four weeks of ingesting a CDD resulted in a significant increase in plasma Hcy (50%) as well as a decrease in liver S-adenosylmethionine (SAM) concentration and S-adenosylmethionine/S-adenosylhomocysteine ratio. No changes were found in plasma methionine and cysteine plasma levels compared to control group. Four weeks of ingesting a CDD also caused a significant (P<0.05) increase in hepatic total fat, hepatic malondialdehyde (MDA), and plasma alanine aminotransferase (ALT) levels. In addition, reduced hepatic glutathione (GSH) levels and reduced/oxidized glutathione ratios (GSH/GSSG) were found in rats fed a CDD compared to controls. Taurine supplementation of the CDD normalized genes involved in the remethylation pathway, BHMT and CHDH, which were impaired by CDD alone. However, taurine supplementation failed to prevent CDD-induced Hcy metabolism disturbances and hepatic injury. Also, taurine added to CDD caused decreased expression of PEMT, CHKa, and CHKb, key genes involved in phosphatidylcholine (PC) synthesis and liver fat accumulation. SIGNIFICANCE Taurine supplementation failed to ameliorate impaired Hcy metabolism and liver injury caused by CDD intake.
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Affiliation(s)
- Rafael Deminice
- Laboratory of Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of São Paulo, Av. Bandeirantes, 3900, Ribeirao Preto, São Paulo, Brazil; Department of Physical Education, Faculty of Physical Education and Sport, State University of Londrina, Rodovia Celso Garcia Cid, Pr 445 Km 380, Campus Universitário, Londrina, Paraná, Brazil.
| | - Flávia Troncon Rosa
- Laboratory of Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of São Paulo, Av. Bandeirantes, 3900, Ribeirao Preto, São Paulo, Brazil
| | - Lilian Eslaine Costa Mendes da Silva
- Laboratory of Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of São Paulo, Av. Bandeirantes, 3900, Ribeirao Preto, São Paulo, Brazil
| | - Alceu Afonso Jordao
- Laboratory of Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of São Paulo, Av. Bandeirantes, 3900, Ribeirao Preto, São Paulo, Brazil
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12
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da Costa KA, Corbin KD, Niculescu MD, Galanko JA, Zeisel SH. Identification of new genetic polymorphisms that alter the dietary requirement for choline and vary in their distribution across ethnic and racial groups. FASEB J 2014; 28:2970-8. [PMID: 24671709 DOI: 10.1096/fj.14-249557] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Effect alleles (alleles with a polymorphism that is associated with the effect being measured) in a small number of single-nucleotide polymorphisms (SNPs) are known to influence the dietary requirement for choline. In this study, we examined a much larger number of SNPs (n=200) in 10 genes related to choline metabolism for associations with development of organ dysfunction (liver or muscle) when 79 humans were fed a low-choline diet. We confirmed that effect alleles in SNPs such as the C allele of PEMT rs12325817 increase the risk of developing organ dysfunction in women when they consume a diet low in choline, and we identified novel effect alleles, such as the C allele of CHKA SNP rs7928739, that alter dietary choline requirements. When fed a low-choline diet, some people presented with muscle damage rather than liver damage; several effect alleles in SLC44A1 (rs7873937, G allele; rs2771040, G; rs6479313, G; rs16924529, A; and rs3199966, C) and one in CHKB (rs1557502, A) were more common in these individuals. This suggests that pathways related to choline metabolism are more important for normal muscle function than previously thought. In European, Mexican, and Asian Americans, and in individuals of African descent, we examined the prevalence of the effect alleles in SNPs that alter choline requirement and found that they are differentially distributed among people of different ethnic and racial backgrounds. Overall, our study has identified novel genetic variants that modulate choline requirements and suggests that the dietary requirement for choline may be different across racial and ethnic groups.-Da Costa, K.-A., Corbin, K. D., Niculescu, M. D., Galanko, J. A., Zeisel, S. H. Identification of new genetic polymorphisms that alter the dietary requirement for choline and vary in their distribution across ethnic and racial groups.
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Affiliation(s)
- Kerry-Ann da Costa
- Department of Nutrition, School of Public Health, School of Medicine, and
| | - Karen D Corbin
- Nutrition Research Institute, University of North Carolina at Chapel Hill, Kannapolis, North Carolina, USA
| | - Mihai D Niculescu
- Nutrition Research Institute, University of North Carolina at Chapel Hill, Kannapolis, North Carolina, USA
| | - Joseph A Galanko
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; and
| | - Steven H Zeisel
- Department of Nutrition, School of Public Health, School of Medicine, and Nutrition Research Institute, University of North Carolina at Chapel Hill, Kannapolis, North Carolina, USA
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Selicharová I, Kořínek M, Demianová Z, Chrudinová M, Mládková J, Jiráček J. Effects of hyperhomocysteinemia and betaine–homocysteine S-methyltransferase inhibition on hepatocyte metabolites and the proteome. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:1596-606. [DOI: 10.1016/j.bbapap.2013.05.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 04/30/2013] [Accepted: 05/10/2013] [Indexed: 12/11/2022]
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14
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Pícha J, Vaněk V, Buděšínský M, Mládková J, Garrow TA, Jiráček J. The development of a new class of inhibitors for betaine-homocysteine S-methyltransferase. Eur J Med Chem 2013; 65:256-75. [DOI: 10.1016/j.ejmech.2013.04.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 04/19/2013] [Accepted: 04/20/2013] [Indexed: 01/12/2023]
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Lee MB, Kooistra M, Zhang B, Slow S, Fortier AL, Garrow TA, Lever M, Trasler JM, Baltz JM. Betaine homocysteine methyltransferase is active in the mouse blastocyst and promotes inner cell mass development. J Biol Chem 2012; 287:33094-103. [PMID: 22847001 DOI: 10.1074/jbc.m112.365478] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Methyltransferases are an important group of enzymes with diverse roles that include epigenetic gene regulation. The universal donor of methyl groups for methyltransferases is S-adenosylmethionine (AdoMet), which in most cells is synthesized using methyl groups carried by a derivative of folic acid. Another mechanism for AdoMet synthesis uses betaine as the methyl donor via the enzyme betaine-homocysteine methyltransferase (BHMT, EC 2.1.1.5), but it has been considered to be significant only in liver. Here, we show that mouse preimplantation embryos contain endogenous betaine; Bhmt mRNA is first expressed at the morula stage; BHMT is abundant at the blastocyst stage but not other preimplantation stages, and BHMT activity is similarly detectable in blastocyst homogenates but not those of two-cell or morula stage embryos. Knockdown of BHMT protein levels and reduction of enzyme activity using Bhmt-specific antisense morpholinos or a selective BHMT inhibitor resulted in decreased development of embryos to the blastocyst stage in vitro and a reduction in inner cell mass cell number in blastocysts. The detrimental effects of BHMT knockdown were fully rescued by the immediate methyl-carrying product of BHMT, methionine. A physiological role for betaine and BHMT in blastocyst viability was further indicated by increased fetal resorption following embryo transfer of BHMT knockdown blastocysts versus control. Thus, mouse blastocysts are unusual in being able to generate AdoMet not only by the ubiquitous folate-dependent mechanism but also from betaine metabolized by BHMT, likely a significant pool of methyl groups in blastocysts.
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Affiliation(s)
- Martin B Lee
- Ottawa Hospital Research Institute, Ottawa, Ontario K1Y4E9, Canada
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16
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Mládková J, Vaněk V, Buděšínský M, Elbert T, Demianová Z, Garrow TA, Jiráček J. Double-headed sulfur-linked amino acids as first inhibitors for betaine-homocysteine S-methyltransferase 2. J Med Chem 2012; 55:6822-31. [PMID: 22775318 DOI: 10.1021/jm300571h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Betaine-homocysteine S-methyltransferase 2 (BHMT-2) catalyzes the transfer of a methyl group from S-methylmethionine to l-homocysteine, yielding two molecules of l-methionine. It is one of three homocysteine methyltransferases in mammals, but its overall contribution to homocysteine remethylation and sulfur amino acid homeostasis is not known. Moreover, recombinant BHMT-2 is highly unstable, which has slowed research on its structural and catalytic properties. In this study, we have prepared the first series of BHMT-2 inhibitors to be described, and we have tested them with human recombinant BHMT-2 that has been stabilized by copurification with human recombinant BHMT. Among the compounds synthesized, (2S,8RS,11RS)-5-thia-2,11-diamino-8-methyldodecanedioic acid (11) was the most potent (K(i)(app) ∼77 nM) and selective inhibitor of BHMT-2. Compound 11 only weakly inhibited human BHMT (IC(50) about 77 μM). This compound (11) may be useful in future in vivo studies to probe the physiological significance of BHMT-2 in sulfur amino acid metabolism.
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Affiliation(s)
- Jana Mládková
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
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Variability of plasma and urine betaine in diabetes mellitus and its relationship to methionine load test responses: an observational study. Cardiovasc Diabetol 2012; 11:34. [PMID: 22510294 PMCID: PMC3395555 DOI: 10.1186/1475-2840-11-34] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 04/17/2012] [Indexed: 11/23/2022] Open
Abstract
Background Since betaine is an osmolyte and methyl donor, and abnormal betaine loss is common in diabetes mellitus (>20% patients), we investigated the relationship between betaine and the post-methionine load rise in homocysteine, in diabetes and control subjects. The post-methionine load test is reported to be both an independent vascular risk factor and a measure of betaine sufficiency. Methods Patients with type 2 diabetes (n = 34) and control subjects (n = 17) were recruited. We measured baseline fasting plasma and 4-hour post-methionine load (L-methionine, 0.1 mg/kg body weight) concentrations of homocysteine, betaine, and the betaine metabolite N,N-dimethylglycine. Baseline urine excretions of betaine, dimethylglycine and glucose were measured on morning urine samples as the ratio to urine creatinine. Statistical determinants of the post-methionine load increase in homocysteine were identified in multiple linear regression models. Results Plasma betaine concentrations and urinary betaine excretions were significantly (p < 0.001) more variable in the subjects with diabetes compared with the controls. Dimethylglycine excretion (p = 0.00014) and plasma dimethylglycine concentrations (p = 0.039) were also more variable. In diabetes, plasma betaine was a significant negative determinant (p < 0.001) of the post-methionine load increase in homocysteine. However, it was not conclusive that this was different from the relationship in the controls. In the patients with diabetes, a strong relationship was found between urinary betaine excretion and urinary glucose excretion (but not with plasma glucose). Conclusions Both high and low plasma betaine concentrations, and high and low urinary betaine excretions, are more prevalent in diabetes. The availability of betaine affects the response in the methionine load test. The benefits of increasing betaine intake should be investigated.
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Kořínek M, Sístek V, Mládková J, Mikeš P, Jiráček J, Selicharová I. Quantification of homocysteine-related metabolites and the role of betaine-homocysteine S-methyltransferase in HepG2 cells. Biomed Chromatogr 2012; 27:111-21. [PMID: 22653757 DOI: 10.1002/bmc.2755] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 04/02/2012] [Accepted: 04/23/2012] [Indexed: 11/11/2022]
Abstract
We optimized and validated a rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of six metabolites of homocysteine metabolism: homocysteine, methionine, cysteine, S-adenosylmethionine, S-adenosylhomocysteine and betaine. The detection limits for these metabolites were in the nanomolar range, and the intra- and inter-day precisions were lower than 20% of the relative standard deviations. The method was specifically designed for the determination of the intracellular concentrations of the metabolites in cultured cells. To study the role of betaine-homocysteine S-methyltransferase (BHMT), HepG2 cells and HepG2 cells that were stably transfected with BHMT ((BHMT) HepG2) were treated with homocysteine or with a specific inhibitor of BHMT, and metabolite levels were subsequently measured. Severely compromised methyl group metabolism in the HepG2 cells, which is typical of cancer-derived cells, prevented clear evaluation of the changes caused by the external manipulations of homocysteine metabolism. However, the ease of handling these cells and the almost unlimited source of experimental material supplied by cells in permanent culture allowed us to develop a reliable methodology. The precautions concerning intracellular metabolite determinations using LC-MS/MS in cultured cells that are expressed in this work will have global validity for future metabolomics studies.
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Affiliation(s)
- Marek Kořínek
- Apigenex s.r.o., Poděbradská 186/56, Prague 9, Czech Republic
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Inhibition of betaine-homocysteine S-methyltransferase in rats causes hyperhomocysteinemia and reduces liver cystathionine β-synthase activity and methylation capacity. Nutr Res 2012; 31:563-71. [PMID: 21840473 DOI: 10.1016/j.nutres.2011.06.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 06/17/2011] [Accepted: 06/18/2011] [Indexed: 11/21/2022]
Abstract
Methylation of homocysteine (Hcy) by betaine-Hcy S-methyltransferase (BHMT) produces methionine, which is required for S-adenosylmethionine (SAM) synthesis. We have recently shown that short-term dietary intake of S-(Δ-carboxybutyl)-dl-Hcy (D,L-CBHcy), a potent and specific inhibitor of BHMT, significantly decreases liver BHMT activity and SAM concentrations but does not have an adverse affect on liver histopathology, plasma markers of liver damage, or DNA methylation in rats. The present study was designed to investigate the hypothesis that BHMT is required to maintain normal liver and plasma amino acid and glutathione profiles, and liver SAM and lipid accumulation. Rats were fed an adequate (4.5 g/kg methionine and 3.7 g/kg cystine), cysteine-devoid (4.5 g/kg methionine and 0 g/kg cystine), or methionine-deficient (1.5 g/kg methionine and 3.7 g/kg cystine) diet either with or without L-CBHcy for 3 or 14 days. All rats fed L-CBHcy had increased total plasma Hcy (2- to 5-fold) and reduced liver BHMT activity (>90%) and SAM concentrations (>40%). S-(Δ-carboxybutyl)-l-Hcy treatment slightly reduced liver glutathione levels in rats fed the adequate or cysteine-devoid diet for 14 days. Rats fed the methionine-deficient diet with L-CBHcy developed fatty liver. Liver cystathionine β-synthase activity was reduced in all L-CBHcy-treated animals, and the effect was exacerbated as time on the L-CBHcy diet increased. Our data indicate that BHMT activity is required to maintain adequate levels of liver SAM and low levels of total plasma Hcy and might be critical for liver glutathione and triglyceride homeostasis under some dietary conditions.
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Teng YW, Mehedint MG, Garrow TA, Zeisel SH. Deletion of betaine-homocysteine S-methyltransferase in mice perturbs choline and 1-carbon metabolism, resulting in fatty liver and hepatocellular carcinomas. J Biol Chem 2011; 286:36258-67. [PMID: 21878621 DOI: 10.1074/jbc.m111.265348] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Betaine-homocysteine S-methyltransferase (BHMT) uses betaine to catalyze the conversion of homocysteine (Hcy) to methionine. There are common genetic polymorphisms in the BHMT gene in humans that can alter its enzymatic activity. We generated the first Bhmt(-/-) mouse to model the functional effects of mutations that result in reduced BHMT activity. Deletion of Bhmt resulted in a 6-fold increase (p < 0.01) in hepatic and an 8-fold increase (p < 0.01) in plasma total Hcy concentrations. Deletion of Bhmt resulted in a 43% reduction in hepatic S-adenosylmethionine (AdoMet) (p < 0.01) and a 3-fold increase in hepatic S-adenosylhomocysteine (AdoHcy) (p < 0.01) concentrations, resulting in a 75% reduction in methylation potential (AdoMet:AdoHcy) (p < 0.01). Bhmt(-/-) mice accumulated betaine in most tissues, including a 21-fold increase in the liver concentration compared with wild type (WT) (p < 0.01). These mice had lower concentrations of choline, phosphocholine, glycerophosphocholine, phosphatidylcholine, and sphingomyelin in several tissues. At 5 weeks of age, Bhmt(-/-) mice had 36% lower total hepatic phospholipid concentrations and a 6-fold increase in hepatic triacyglycerol concentrations compared with WT (p < 0.01), which was due to a decrease in the secretion of very low density lipoproteins. At 1 year of age, 64% of Bhmt(-/-) mice had visible hepatic tumors. Histopathological analysis revealed that Bhmt(-/-) mice developed hepatocellular carcinoma or carcinoma precursors. These results indicate that BHMT has an important role in Hcy, choline, and one-carbon homeostasis. A lack of Bhmt also affects susceptibility to fatty liver and hepatocellular carcinoma. We suggest that functional polymorphisms in BHMT that significantly reduce activity may have similar effects in humans.
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Affiliation(s)
- Ya-Wen Teng
- Department of Nutrition, School of Public Health, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Ganu RS, Garrow TA, Sodhi M, Rund LA, Schook LB. Molecular characterization and analysis of the porcine betaine homocysteine methyltransferase and betaine homocysteine methyltransferase-2 genes. Gene 2010; 473:133-8. [PMID: 21156199 DOI: 10.1016/j.gene.2010.11.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 11/25/2010] [Accepted: 11/29/2010] [Indexed: 02/03/2023]
Abstract
Betaine homocysteine methyltransferase (BHMT) and BHMT-2 enzymes methylate homocysteine to form methionine using betaine and S-methylmethionine, respectively. These activities are observed only in the liver of adult rodents, but in adult humans and pigs these activities are detected in both the liver and kidney, indicating the pig is a more appropriate model for studying the biochemical and physiological roles of these enzymes in human biology. Porcine BHMT and BHMT-2 cDNAs were cloned and sequenced, and their 5' and 3' UTR were amplified using RLM-RACE. The BHMT transcript had significantly longer 5' and 3' UTRs than BHMT-2. The pig BHMT and BHMT-2 genes span approximately 26 and 16kb, respectively, and both genes have 8 exons. The deduced amino acid sequences of BHMT and BHMT-2 contain 407 and 363 amino acids, respectively, and shared 78% amino acid identity. No promoter element (TATA or CAAT box) was observed for either BHMT or BHMT-2, although a CpG island surrounding the promoter and transcriptional start site was observed in both genes implying that methylation could regulate their expression. Using qPCR, it was determined that BHMT and BHMT-2 transcripts are very abundant in liver and kidney cortex, whereas the expression is significantly less in other tissues. These findings confirm that the expression pattern of BHMT and BHMT-2 genes in pigs is similar to humans, supporting the use of the pig as an animal model to study the genetics and regulation of BHMT and BHMT-2 expression.
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Affiliation(s)
- Radhika S Ganu
- Division of Nutritional Sciences, University of Illinois at Urbana Champaign, 1201 W. Gregory Dr., Urbana, IL 61801, USA
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Strakova J, Williams KT, Gupta S, Schalinske KL, Kruger WD, Rozen R, Jiracek J, Li L, Garrow TA. Dietary intake of S-(alpha-carboxybutyl)-DL-homocysteine induces hyperhomocysteinemia in rats. Nutr Res 2010; 30:492-500. [PMID: 20797482 PMCID: PMC2929918 DOI: 10.1016/j.nutres.2010.06.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 06/30/2010] [Accepted: 06/30/2010] [Indexed: 11/16/2022]
Abstract
Betaine homocysteine S-methyltransferase (BHMT) catalyzes the transfer of a methyl group from betaine to homocysteine (Hcy), forming dimethylglycine and methionine. We previously showed that inhibiting BHMT in mice by intraperitoneal injection of S-(alpha-carboxybutyl)-DL-homocysteine (CBHcy) results in hyperhomocysteinemia. In the present study, CBHcy was fed to rats to determine whether it could be absorbed and cause hyperhomocysteinemia as observed in the intraperitoneal administration of the compound in mice. We hypothesized that dietary administered CBHcy will be absorbed and will result in the inhibition of BHMT and cause hyperhomocysteinemia. Rats were meal-fed every 8 hours an L-amino acid-defined diet either containing or devoid of CBHcy (5 mg per meal) for 3 days. The treatment decreased liver BHMT activity by 90% and had no effect on methionine synthase, methylenetetrahydrofolate reductase, phosphatidylethanolamine N-methyltransferase, and CTP:phosphocholine cytidylyltransferase activities. In contrast, cystathionine beta-synthase activity and immunodetectable protein decreased (56% and 26%, respectively) and glycine N-methyltransferase activity increased (52%) in CBHcy-treated rats. Liver S-adenosylmethionine levels decreased by 25% in CBHcy-treated rats, and S-adenosylhomocysteine levels did not change. Furthermore, plasma choline decreased (22%) and plasma betaine increased (15-fold) in CBHcy-treated rats. The treatment had no effect on global DNA and CpG island methylation, liver histology, and plasma markers of liver damage. We conclude that CBHcy-mediated BHMT inhibition causes an elevation in total plasma Hcy that is not normalized by the folate-dependent conversion of Hcy to methionine. Furthermore, metabolic changes caused by BHMT inhibition affect cystathionine beta-synthase and glycine N-methyltransferase activities, which further deteriorate plasma Hcy levels.
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Affiliation(s)
- Jana Strakova
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Kelly T. Williams
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
| | - Sapna Gupta
- Division of Population Science, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Kevin L. Schalinske
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
| | - Warren D. Kruger
- Division of Population Science, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Rima Rozen
- Departments of Human Genetics and Pediatrics, McGill University Health Centre-Montreal Children's Hospital, Montreal, Quebec, Canada
| | - Jiri Jiracek
- Biological Chemistry Department, Institute of Organic Chemistry and Biochemistry, Academy of Science of the Czech Republic, Prague 166 10, Czech Republic
| | - Lucas Li
- Metabolomics Center, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Timothy A. Garrow
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Lever M, Slow S. The clinical significance of betaine, an osmolyte with a key role in methyl group metabolism. Clin Biochem 2010; 43:732-44. [DOI: 10.1016/j.clinbiochem.2010.03.009] [Citation(s) in RCA: 273] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 03/16/2010] [Accepted: 03/17/2010] [Indexed: 01/29/2023]
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Chen NC, Yang F, Capecci LM, Gu Z, Schafer AI, Durante W, Yang XF, Wang H. Regulation of homocysteine metabolism and methylation in human and mouse tissues. FASEB J 2010; 24:2804-17. [PMID: 20305127 DOI: 10.1096/fj.09-143651] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Hyperhomocysteinemia is an independent risk factor for cardiovascular disease. Homocysteine (Hcy) metabolism involves multiple enzymes; however, tissue Hcy metabolism and its relevance to methylation remain unknown. Here, we established gene expression profiles of 8 Hcy metabolic and 12 methylation enzymes in 20 human and 19 mouse tissues through bioinformatic analysis using expression sequence tag clone counts in tissue cDNA libraries. We analyzed correlations between gene expression, Hcy, S-adenosylhomocysteine (SAH), and S-adenosylmethionine (SAM) levels, and SAM/SAH ratios in mouse tissues. Hcy metabolic and methylation enzymes were classified into two types. The expression of Type 1 enzymes positively correlated with tissue Hcy and SAH levels. These include cystathionine beta-synthase, cystathionine-gamma-lyase, paraxonase 1, 5,10-methylenetetrahydrofolate reductase, betaine:homocysteine methyltransferase, methionine adenosyltransferase, phosphatidylethanolamine N-methyltransferases and glycine N-methyltransferase. Type 2 enzyme expressions correlate with neither tissue Hcy nor SAH levels. These include SAH hydrolase, methionyl-tRNA synthase, 5-methyltetrahydrofolate:Hcy methyltransferase, S-adenosylmethionine decarboxylase, DNA methyltransferase 1/3a, isoprenylcysteine carboxyl methyltransferases, and histone-lysine N-methyltransferase. SAH is the only Hcy metabolite significantly correlated with Hcy levels and methylation enzyme expression. We established equations expressing combined effects of methylation enzymes on tissue SAH, SAM, and SAM/SAH ratios. Our study is the first to provide panoramic tissue gene expression profiles and mathematical models of tissue methylation regulation.
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Affiliation(s)
- Natalie C Chen
- Department of Pharmacology, Temple University School of Medicine, 3420 North Broad St., MRB, Philadelphia, PA 19140, USA
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Abstract
Homocysteine is a metabolic intermediate in methyl group metabolism that is dependent on a number of nutritional B-vitamin cofactors. An emerging aspect of homocysteine metabolism is its relation to health and disease. Perturbations of homocysteine metabolism, particularly intracellular and subsequently circulating accumulation of homocysteine (i.e., hyperhomocysteinemia), are associated with vascular disease risk, as well as other pathologies. However, intervention with B-vitamin supplementation has been shown to successfully restore normal homocysteine concentrations, but without concomitant reductions in disease risk. Thus, the mechanistic relation between homocysteine balance and disease states, as well as the value of homocysteine management, remains an area of intense investigation.
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Affiliation(s)
- Kelly T Williams
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
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Inhibition of nitric oxide synthesis during induced cholestasis ameliorates hepatocellular injury by facilitating S-nitrosothiol homeostasis. J Transl Med 2010; 90:116-27. [PMID: 19806079 DOI: 10.1038/labinvest.2009.104] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cholestatic liver injury following extra- or intrahepatic bile duct obstruction causes nonparenchymal cell proliferation and matrix deposition leading to end-stage liver disease and cirrhosis. In cholestatic conditions, nitric oxide (NO) is mainly produced by a hepatocyte-inducible NO synthase (iNOS) as a result of enhanced inflow of endotoxins to the liver and also by accumulation of bile salts in hepatocytes and subsequent hepatocellular injury. This study was aimed to investigate the role of NO and S-nitrosothiol (SNO) homeostasis in the development of hepatocellular injury during cholestasis induced by bile duct ligation (BDL) in rats. Male Wistar rats (200-250 g) were divided into four groups (n=10 each), including sham-operated (SO), bile duct-ligated (BDL), tauroursodeoxycholic acid (TUDCA, 50 mg/kg) and S-methylisothiourea (SMT, 25 mg/kg) treated. After 7 days, BDL rats showed elevated serum levels of gamma-glutamiltranspeptidase, aspartate aminotransferase, alanine aminotransferase, LDH, and bilirubin, bile duct proliferation and fibrosis, compared with the SO group. TUDCA treatment did not significantly alter these parameters, but the iNOS inhibitor SMT ameliorated hepatocellular injury, as shown by lower levels of circulating hepatic enzymes and bilirubin, and a decreased grade of bile duct proliferation and fibrosis. Both TUDCA and SMT treatments reversed Mrp2 canalicular pump expression to control levels. However, only SMT treatment significantly lowered the increased levels of plasma NO and S-nitrosation (S-nitrosylation) of liver proteins in BDL rats. Moreover, BDL resulted in a reduction of the S-nitrosoglutathione reductase (GSNOR/Adh5) enzymatic activity and a downregulation of the GSNOR/Adh5 mRNA expression that was reverted by SMT, but not TUDCA, treatment. A total of 25 liver proteins, including S-adenosyl methionine synthetase, betaine-homocysteine S-methyltransferase, Hsp90 and protein disulfide isomerase, were found to be S-nitrosated in BDL rats. In conclusion, the inhibition of NO production during induced cholestasis ameliorates hepatocellular injury. This effect is in part mediated by the improvement of cell proficiency in maintaining SNO homeostasis.
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Newton BW, Russell WK, Russell DH, Ramaiah SK, Jayaraman A. Liver proteome analysis in a rodent model of alcoholic steatosis. J Proteome Res 2009; 8:1663-71. [PMID: 19714808 DOI: 10.1021/pr800905w] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Alcoholic steatosis (AS) is the initial pathology associated with early stage alcoholic liver disease (ALD) and is characterized by the accumulation of fat in the liver. AS is considered clinically benign because it is reversible, and the progression of AS to alcoholic steatohepatitis (ASH) is a key step in the development of ALD. A two-dimensional gel electrophoresis (2DE)-mass spectrometry (MS) proteomic approach was used to investigate the protein expression pattern underlying AS, as the first step toward determining liver tissue biomarkers for early stage ALD. Several proteins involved in fatty acid and amino acid metabolism were up-regulated in 3- and 6-week ethanol-fed rats relative to isocaloric controls, which suggest a higher energy demand upon chronic exposure to ethanol. In addition, the expression of two proteins associated with alcohol-induced oxidative stress, peroxiredoxin 6 (PRDX6) and aldehyde dehydrogenase 2 (ALDH2), was down-regulated in ethanol fed rats, and suggests an increase in reactive oxygen species and oxidative stress. To investigate if irreversible protein modification arising from oxidative stress during AS impacts protein levels, the extent of carbonylated proteins in the ethanol and isocaloric groups was identified using mass spectrometry. The detection of modified proteins involved in antioxidant functions further supports the notion that oxidative modification of these proteins leads to protein turnover during AS. In addition, the carbonylation of betaine-homocysteine S-methyltransferase, a protein implicated in fatty liver development, in 3-week and 6-week ethanol exposed samples suggests that this protein could be a marker for early stage AS.
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Affiliation(s)
- Billy W Newton
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843-3122, USA
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Vanek V, Budesínský M, Kabeleová P, Sanda M, Kozísek M, Hanclová I, Mládková J, Brynda J, Rosenberg I, Koutmos M, Garrow TA, Jirácek J. Structure-activity study of new inhibitors of human betaine-homocysteine S-methyltransferase. J Med Chem 2009; 52:3652-65. [PMID: 19534555 DOI: 10.1021/jm8015798] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Betaine-homocysteine S-methyltransferase (BHMT) catalyzes the transfer of a methyl group from betaine to l-homocysteine, yielding dimethylglycine and l-methionine. In this study, we prepared a new series of BHMT inhibitors. The inhibitors were designed to mimic the hypothetical transition state of BHMT substrates and consisted of analogues with NH, N(CH(3)), or N(CH(3))(2) groups separated from the homocysteine sulfur atom by a methylene, ethylene, or a propylene spacer. Only the inhibitor with the N(CH(3)) moiety and ethylene spacer gave moderate inhibition. This result led us to prepare two inhibitors lacking a nitrogen atom in the S-linked alkyl chain: (RS,RS)-5-(3-amino-3-carboxypropylthio)-3-methylpentanoic acid and (RS)-5-(3-amino-3-carboxypropylthio)-3,3-dimethylpentanoic acid. Both of these compounds were highly potent inhibitors of BHMT. The finding that BHMT does not tolerate a true betaine mimic within these inhibitors, especially the nitrogen atom, is surprising and evokes questions about putative conformational changes of BHMT upon the binding of the substrates/products and inhibitors.
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Affiliation(s)
- Václav Vanek
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nam. 2, 166 10 Prague 6, Czech Republic
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Obeid R, Herrmann W. Homocysteine and lipids: S-adenosyl methionine as a key intermediate. FEBS Lett 2009; 583:1215-25. [PMID: 19324042 DOI: 10.1016/j.febslet.2009.03.038] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 02/20/2009] [Accepted: 03/02/2009] [Indexed: 12/23/2022]
Abstract
An association between hyperlipidemia and hyperhomocysteinemia (HHCY) has been suggested. This link is clinically important in management of vascular risk factors especially in elderly people and patients with metabolic syndrome. Higher plasma homocysteine (Hcy) was associated with lower high-density lipoprotein (HDL)-cholesterol level. Moreover, HHCY was associated with disturbed plasma lipids or fatty liver. It seems that hypomethylation associated with HHCY is responsible for lipid accumulation in tissues. Decreased methyl group will decrease the synthesis of phosphatidylcholine, a major phospholipid required for very low-density lipoprotein (VLDL) assembly and homeostasis. The effect of Hcy on HDL-cholesterol is probably related to inhibiting enzymes or molecules participating in HDL-particle assembly.
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Affiliation(s)
- Rima Obeid
- Department of Clinical Chemistry and Laboratory Medicine, Central Laboratory, University Hospital, Saarland University, D-66424 Homburg/Saar, Germany
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30
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Abratte CM, Wang W, Li R, Axume J, Moriarty DJ, Caudill MA. Choline status is not a reliable indicator of moderate changes in dietary choline consumption in premenopausal women. J Nutr Biochem 2009; 20:62-9. [DOI: 10.1016/j.jnutbio.2007.12.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Revised: 11/30/2007] [Accepted: 12/12/2007] [Indexed: 01/13/2023]
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Abstract
In the early 1930s, Banting and Best, the discoverers of insulin, found that choline could prevent the development of fatty liver disease (steatosis) in pancreatectomized dogs treated with insulin. Later work indicated that in rats and mice, diets deficient in labile methyl groups (choline, methionine, betaine, folate) produced fatty liver and that long-term administration of diets deficient in choline and methionine also caused hepatocellular carcinoma. These experiments not only linked steatosis and diabetes but also provided evidence, for the first time, of the importance of labile methyl group balance to maintain normal liver function. This conclusion is now amply supported by the observation of mice devoid of key enzymes of methionine and folate metabolism and in patients with severe deficiencies in these enzymes. Moreover, treatments with various methionine metabolites in experimental animal models of liver disease show hepatoprotective properties.
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Affiliation(s)
- José M Mato
- CIC bioGUNE, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (ciberhed), Technology Park of Bizkaia, 48160 Derio, Bizkaia, Spain.
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32
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Veenema K, Solis C, Li R, Wang W, Maletz CV, Abratte CM, Caudill MA. Adequate Intake levels of choline are sufficient for preventing elevations in serum markers of liver dysfunction in Mexican American men but are not optimal for minimizing plasma total homocysteine increases after a methionine load. Am J Clin Nutr 2008; 88:685-92. [PMID: 18779284 PMCID: PMC2637180 DOI: 10.1093/ajcn/88.3.685] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND An adequate intake of 550 mg choline/d was established for the prevention of liver dysfunction in men, as assessed by measuring serum alanine aminotransferase concentrations. OBJECTIVE This controlled feeding study investigated the influence of choline intakes ranging from 300 to 2200 mg/d on biomarkers of choline status. The effect of the methylenetetrahydrofolate reductase (MTHFR) C677T genotype on choline status was also examined. DESIGN Mexican American men (n = 60) with different MTHFR C677T genotypes (29 677TT, 31 677CC) consumed a diet providing 300 mg choline/d plus supplemental choline intakes of 0, 250, 800, or 1900 mg/d for total choline intakes of 300, 550, 1100, or 2200 mg/d, respectively, for 12 wk; 400 mug/d as dietary folate equivalents and 173 mg betaine/d were consumed throughout the study. RESULTS Choline intake affected the response of plasma free choline and betaine (time x choline, P < 0.001); the highest concentrations were observed in the 2200 mg/d group. Phosphatidylcholine (P = 0.026) and total cholesterol (P = 0.002) were also influenced by choline intake; diminished concentrations were observed in the 300 mg/d group. Phosphatidylcholine was modified by MTHFR genotype (P = 0.035; 677TT < 677CC). After a methionine load (100 mg/kg body wt), choline intakes of 1100 and 2200 mg/d attenuated (P = 0.016) the rise in plasma homocysteine, as did the MTHFR 677TT genotype (P < 0.001). Serum alanine aminotransferase was not influenced by the choline intakes administered in this study. CONCLUSIONS These data suggest that 550 mg choline/d is sufficient for preventing elevations in serum markers of liver dysfunction in this population under the conditions of this study; higher intakes may be needed to optimize other endpoints.
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Affiliation(s)
- Kristin Veenema
- Department of Human Nutrition, Cal Poly Pomona, Pomona, CA, USA
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Dayal S, Lentz SR. Murine models of hyperhomocysteinemia and their vascular phenotypes. Arterioscler Thromb Vasc Biol 2008; 28:1596-605. [PMID: 18556571 DOI: 10.1161/atvbaha.108.166421] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hyperhomocysteinemia is an established risk factor for arterial as well as venous thromboembolism. Individuals with severe hyperhomocysteinemia caused by inherited genetic defects in homocysteine metabolism have an extremely high incidence of vascular thrombosis unless they are treated aggressively with homocysteine-lowering therapy. The clinical value of homocysteine-lowering therapy in individuals with moderate hyperhomocysteinemia, which is very common in populations at risk for vascular disease, is more controversial. Considerable progress in our understanding of the molecular mechanisms underlying the association between hyperhomocysteinemia and vascular thrombotic events has been provided by the development of a variety of murine models. Because levels of homocysteine are regulated by both the methionine and folate cycles, hyperhomocysteinemia can be induced in mice through both genetic and dietary manipulations. Mice deficient in the cystathionine beta-synthase (CBS) gene have been exploited widely in many studies investigating the vascular pathophysiology of hyperhomocysteinemia. In this article, we review the established murine models, including the CBS-deficient mouse as well as several newer murine models available for the study of hyperhomocysteinemia. We also summarize the major vascular phenotypes observed in these murine models.
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Affiliation(s)
- Sanjana Dayal
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, USA
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34
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Hung J, Abratte CM, Wang W, Li R, Moriarty DJ, Caudill MA. Ethnicity and Folate Influence Choline Status in Young Women Consuming Controlled Nutrient Intakes. J Am Coll Nutr 2008; 27:253-9. [DOI: 10.1080/07315724.2008.10719697] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Atkinson W, Elmslie J, Lever M, Chambers ST, George PM. Dietary and supplementary betaine: acute effects on plasma betaine and homocysteine concentrations under standard and postmethionine load conditions in healthy male subjects. Am J Clin Nutr 2008; 87:577-85. [PMID: 18326594 DOI: 10.1093/ajcn/87.3.577] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Betaine comes from the diet and from choline, and it is associated with vascular disease in some patient groups. Betaine supplementation lowers plasma total homocysteine. OBJECTIVE We compared the acute effects of dietary and supplementary betaine and choline on plasma betaine and homocysteine under standard conditions and after a methionine load. DESIGN In a randomized crossover study, 8 healthy men (19-40 y) consumed a betaine supplement (approximately 500 mg), high-betaine meal (approximately 517 mg), choline supplement (500 mg), high-choline meal (approximately 564 mg), high-betaine and -choline meal (approximately 517 mg betaine, approximately 622 mg choline), or a low-betaine and -choline control meal under standard conditions or postmethionine load. Plasma betaine, dimethylglycine, and homocysteine concentrations were measured hourly for 8 h and at 24 h after treatment. RESULTS Dietary and supplementary betaine raised plasma betaine concentrations relative to control (P < 0.001) under standard conditions. This was not associated with raised plasma dimethylglycine concentration, and no significant betaine appeared in the urine. A small increase in dimethylglycine excretion was observed when either betaine or choline was supplied (P = 0.011 and < 0.001). Small decreases in plasma homocysteine 6 h after ingestion under standard conditions (P < or = 0.05) were detected after a high-betaine meal and after a high-betaine and high-choline meal. Dietary betaine and choline and betaine supplementation attenuated the increase in plasma homocysteine at both 4 and 6 h after a methionine load (P < or = 0.001). CONCLUSIONS Dietary betaine and supplementary betaine acutely increase plasma betaine, and they and choline attenuate the postmethionine load rise in homocysteine concentrations.
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Affiliation(s)
- Wendy Atkinson
- Clinical Biochemistry Unit, Canterbury Health Laboratories, Christchurch, New Zealand
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36
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Solis C, Veenema K, Ivanov AA, Tran S, Li R, Wang W, Moriarty DJ, Maletz CV, Caudill MA. Folate intake at RDA levels is inadequate for Mexican American men with the methylenetetrahydrofolate reductase 677TT genotype. J Nutr 2008; 138:67-72. [PMID: 18156406 PMCID: PMC2646848 DOI: 10.1093/jn/138.1.67] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Since the establishment of the 1998 folate recommended dietary allowance (RDA), the methylenetetrahydrofolate reductase (MTHFR) 677C-->T variant has emerged as a strong modifier of folate status. This controlled feeding study investigated the adequacy of the RDA, 400 microg/d as dietary folate equivalents (DFE), for Mexican American men with the MTHFR 677CC or TT genotype. Because of the interdependency between folate and choline, the influence of choline intake on folate status was also assessed. Mexican American men (n = 60; 18-55 y) with the MTHFR 677CC (n = 31) or TT (n = 29) genotype consumed 438 microg DFE/d and total choline intakes of 300, 550 (choline adequate intake), 1100, or 2200 mg/d for 12 wk. Folate status response was assessed via serum folate (SF), RBC folate, plasma total homocysteine (tHcy), and urinary folate. SF decreased (P < 0.001) 66% to 7.9 +/- 0.7 nmol/L (means +/- SEM) in men with the 677TT genotype and 62% to 11.3 +/- 0.9 nmol/L in the 677CC genotype. Plasma tHcy increased (P < 0.0001) 170% to 31 +/- 3 micromol/L in men with the 677TT genotype and 18% to 11.6 +/- 0.3 micromol/L in the 677CC genotype. At the end of the study, 34% (677TT) and 16% (677CC) had SF concentrations <6.8 nmol/L and 79% (677TT) and 7% (677CC) had tHcy concentrations >14 micromol/L. Choline intake did not influence the response of the measured variables. These data showed that the folate RDA is not adequate for men of Mexican descent, particularly for those with the MTHFR 677TT genotype, and demonstrated a lack of influence of choline intake on the folate status variables measured in this study.
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Affiliation(s)
- Claudia Solis
- Human Nutrition and Food Science Department, Cal Poly Pomona University, Pomona, CA 91768, USA
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Effects of orange juice and proline betaine on glycine betaine and homocysteine in healthy male subjects. Eur J Nutr 2007; 46:446-52. [PMID: 18060588 DOI: 10.1007/s00394-007-0684-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Accepted: 10/09/2007] [Indexed: 10/22/2022]
Abstract
BACKGROUND Proline betaine (PB), a glycine betaine (GB) analogue found in citrus foods, increases urinary GB loss and plasma total homocysteine (tHcy) concentrations in rats. Its presence in human plasma is associated with increased GB excretion. AIM To compare the effects of dietary levels of PB on GB excretion, and on plasma tHcy and GB concentrations in healthy volunteers. METHODS In a randomized crossover study, eight healthy males (18-50 years) ingested either 750 mL orange juice (containing 0.545 g PB), a PB supplement (0.545 g PB dissolved in 750 mL apple juice), or 750 mL apple juice (control). Plasma PB, GB and tHcy, and urine PB, GB and creatinine concentrations were measured hourly for 6 h and at 24 h post-treatment. RESULTS Plasma tHcy concentrations were not increased (relative to control) following ingestion of either orange juice or PB supplement. Both treatments produced a significant increase in plasma PB concentrations (P < 0.001), this effect being greater following orange juice compared with PB supplement (P < 0.05, 1-2 h). Urinary excretion of PB was greater than the control following both orange juice (P < 0.001) and PB supplement (P < 0.001), from 2 to 24 h post-treatment. This increase in PB excretion was significantly greater following orange juice compared with PB supplement with higher peak excretion (Cmax difference, P = 0.008). GB excretion was significantly greater following ingestion of orange juice compared with PB in apple juice (P = 0.007) and apple juice control (P < 0.001) in the first 2 h post-ingestion. CONCLUSIONS PB administered in dietary doses had little effect on plasma tHcy concentrations in healthy humans. Ingestion of PB in orange juice compared with PB alone resulted in greater increases in the urinary excretion of PB and GB.
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Lever M, Atkinson W, George PM, Chambers ST. Sex differences in the control of plasma concentrations and urinary excretion of glycine betaine in patients attending a lipid disorders clinic. Clin Biochem 2007; 40:1225-31. [PMID: 17706956 DOI: 10.1016/j.clinbiochem.2007.05.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Revised: 05/22/2007] [Accepted: 05/23/2007] [Indexed: 11/21/2022]
Abstract
OBJECTIVES To find whether the control of betaine metabolism differs between male and female patients and identify the effects of insulin and other hormones. DESIGN AND METHODS Data from non-diabetic lipid clinic patients (82 female symbol and 76 male symbol) were re-analyzed by sex. Data on insulin, thyroid hormones and leptin were included in models to identify factors affecting the circulation and excretion of betaine and its metabolites. RESULTS Different factors influenced plasma concentrations and urinary excretion of betaine, dimethylglycine and homocysteine in males and females. In males, apolipoprotein B (negative), thyroid stimulating hormone (positive) and insulin (negative) predicted circulating betaine, consistent with betaine-homocysteine methyltransferase mediated control. In females, insulin positively predicted plasma dimethylglycine. Urinary betaine excretion positively predicted circulating homocysteine in males (p<0.001), whereas dimethylglycine excretion (also indicating betaine loss) was a stronger positive predictor (p<0.001) in females. Carnitine affected betaine homeostasis. CONCLUSIONS Betaine metabolism is under endocrine control, and studies should use sex stratified groups.
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Affiliation(s)
- Michael Lever
- Clinical Biochemistry Unit, Canterbury Health Laboratories, Christchurch, New Zealand.
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Elmore CL, Matthews RG. The many flavors of hyperhomocyst(e)inemia: insights from transgenic and inhibitor-based mouse models of disrupted one-carbon metabolism. Antioxid Redox Signal 2007; 9:1911-21. [PMID: 17696766 PMCID: PMC3112351 DOI: 10.1089/ars.2007.1795] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mouse models that perturb homocysteine metabolism, including genetic mouse models that result in deficiencies of methylenetetrahydrofolate reductase, methionine synthase, methionine synthase reductase, and cystathionine beta-synthase, and a pharmaceutically induced mouse model with a transient deficiency in betainehomocysteine methyl transferase, have now been characterized and can be compared. Although each of these enzyme deficiencies is associated with moderate to severe hyperhomocyst(e)inemia, the broader metabolic profiles are profoundly different. In particular, the various models differ in the degree to which tissue ratios of S-adenosylmethionine to S-adenosylhomocysteine are reduced in the face of elevated plasma homocyst(e)ine, and in the distribution of the tissue folate pools. These different metabolic profiles illustrate the potential complexities of hyperhomocyst(e)inemia in humans and suggest that comparison of the disease phenotypes of the various mouse models may be extremely useful in dissecting the underlying risk factors associated with human hyperhomocyst(e)inemia.
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Affiliation(s)
- C Lee Elmore
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109-2216, USA
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Lever M, Atkinson W, George PM, Chambers ST. An abnormal urinary excretion of glycine betaine may persist for years. Clin Biochem 2007; 40:798-801. [PMID: 17490630 DOI: 10.1016/j.clinbiochem.2007.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 03/14/2007] [Indexed: 01/15/2023]
Abstract
OBJECTIVES Does abnormal betaine excretion persist? DESIGN AND METHODS Patients (10) with abnormal excretion in 1998 were recalled in 2005. Subsequent urine samples were collected on 4 days from persistently abnormal subjects. RESULTS Half the 1998 abnormal patients were abnormal in 2005. Only 1/20 controls was abnormal (p=0.015). All patients with abnormal excretion in 1998 and 2005 had abnormal excretion on successive days while no controls did. CONCLUSIONS High betaine excretion may be chronic and a health risk.
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Affiliation(s)
- Michael Lever
- Clinical Biochemistry Unit, Canterbury Health Laboratories, Christchurch School of Medicine and Health Sciences, Christchurch, New Zealand.
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Uthus EO, Ross SA. Dietary selenium affects homocysteine metabolism differently in Fisher-344 rats and CD-1 mice. J Nutr 2007; 137:1132-6. [PMID: 17449570 DOI: 10.1093/jn/137.5.1132] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In our previous work with rats, plasma and tissue homocysteine concentrations were decreased by selenium deprivation. The purpose of this study was to follow up and expand on that work by determining the effects of selenium status (deficient, adequate, and supranutritional) on several aspects of homocysteine metabolism involving methionine recycling and transsulfuration. A 2nd objective was to determine whether there are differences in how selenium status affects homocysteine metabolism in rats and mice. Male weanling Fischer-344 rats and male weanling CD-1 mice were fed diets containing 0, 0.2, or 2.0 microg selenium (as sodium selenite)/g for 72 d or 60 d, respectively. Plasma homocysteine and cysteine were significantly decreased by feeding rats or mice the selenium-deficient diet compared with feeding adequate or supranutritional selenium. On the other hand, plasma glutathione was increased by selenium deficiency only in rats. Also, the specific activities of liver betaine homocysteine methyltransferase and glycine N-methyltransferase were decreased by selenium deficiency in rats, but were unaffected by selenium status in mice. Real-time RT-PCR was used to determine the expression of the subunits of glutamate-cysteine ligase, which catalyzes the rate-limiting step in glutathione biosynthesis. The expression of Gclc, the catalytic subunit of glutamate-cysteine ligase, was upregulated by selenium deprivation in both rat and mouse liver. Gclm, the modifier subunit of glutamate-cysteine ligase, was downregulated in rats fed 2 microg Se/g compared with rats fed adequate or deficient selenium. Based on these findings, it is evident that selenium deficiency has different outcomes in mice and rats. These variables are all related to methionine/methyl metabolism. Although only one strain of rat was compared with one strain of mouse, this work suggests that differences between species may prove vital in determining which animal model is used in studies of selenium deficiency or in studies that are designed to ascertain chemopreventive mechanisms of selenium.
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Affiliation(s)
- Eric O Uthus
- USDA, ARS, Grand Forks Human Nutrition Research Center, Grand Forks, ND 58202, USA.
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Cohen-Salmon M, Regnault B, Cayet N, Caille D, Demuth K, Hardelin JP, Janel N, Meda P, Petit C. Connexin30 deficiency causes instrastrial fluid-blood barrier disruption within the cochlear stria vascularis. Proc Natl Acad Sci U S A 2007; 104:6229-34. [PMID: 17400755 PMCID: PMC1851033 DOI: 10.1073/pnas.0605108104] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The endocochlear potential (EP) is essential to hearing, because it provides approximately half of the driving force for the mechanoelectrical transduction current in auditory hair cells. The EP is produced by the stria vascularis (SV), a vascularized bilayer epithelium of the cochlea lateral wall. The absence of the gap junction protein connexin30 (Cx30) in Cx30(-/-) mice results in the SV failure to produce an EP, which mainly accounts for the severe congenital hearing impairment of these mice. Here, we show that the SV components of the EP electrogenic machinery and the epithelial barriers limiting the intrastrial fluid space, which are both necessary for the EP production, were preserved in Cx30(-/-) mice. In contrast, the endothelial barrier of the capillaries supplying the SV was disrupted before EP onset. This disruption is expected to result in an intrastrial electric shunt that is sufficient to account for the absence of the EP production. Immunofluorescence analysis of wild-type mice detected Cx30 in the basal and intermediate cells of the SV but not in the endothelial cells of the SV capillaries. Moreover, dye-coupling experiments showed that endothelial cells were not coupled to the SV basal, intermediate, and marginal cells. SV transcriptome analysis revealed a significant down-regulation of betaine homocysteine S-methyltransferase (Bhmt) in the Cx30(-/-) mice, which was restricted to the SV and resulted in a local increase in homocysteine, a known factor of endothelial dysfunction. Disruption of the SV endothelial barrier is a previously undescribed pathogenic process underlying hearing impairment.
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Affiliation(s)
- Martine Cohen-Salmon
- Unité de Génétique des Déficits Sensoriels, Unité Mixte de Recherche S 587, Institut National de la Santé et de la Recherche Médicale, 75724 Paris Cedex 15, France.
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Williams KT, Schalinske KL. New insights into the regulation of methyl group and homocysteine metabolism. J Nutr 2007; 137:311-4. [PMID: 17237303 DOI: 10.1093/jn/137.2.311] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Hepatic folate, methyl group, and homocysteine metabolism are interrelated pathways that when disrupted are associated with numerous pathologies. Maintenance of normal methyl group and homocysteine homeostasis is dependent on the balance between: S-adenosylmethionine (SAM)-dependent transmethylation, which utilizes methyl groups and produces homocysteine; remethylation of homocysteine back to methionine by folate-dependent and -independent mechanisms; and homocysteine catabolism via the transsulfuration pathway. Recent studies have demonstrated that hormonal imbalance is a factor in the control of key proteins that regulate these pathways. A diabetic state is characterized by increased expression of specific methyltransferases that utilize SAM-derived methyl groups and produce homocysteine. Although the supply of methyl groups from the folate-dependent 1-carbon pool appears to be diminished under diabetic conditions, the increased production of homocysteine is compensated for by stimulation of folate-independent remethylation and catabolism by transsulfuration, resulting in hypohomocysteinemia. Similar changes have been observed with glucocorticoid administration and in a growth hormone-deficient model, which can be prevented by insulin and growth hormone treatment, respectively. Taken together, these reports clearly indicate that hormonal regulation is a major factor in the metabolic control of folate, methyl groups, and homocysteine, thereby providing a potential link between the pathologies associated with these pathways and hormonal imbalance.
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Affiliation(s)
- Kelly T Williams
- Department of Food Science and Human Nutrition, Iowa State University, Ames IA 50011, USA
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Lever M, Atkinson W, Sizeland PCB, Chambers ST, George PM. Inter- and intra-individual variations in normal urinary glycine betaine excretion. Clin Biochem 2007; 40:447-53. [PMID: 17335790 DOI: 10.1016/j.clinbiochem.2006.10.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 08/23/2006] [Accepted: 10/10/2006] [Indexed: 01/15/2023]
Abstract
OBJECTIVES To establish whether normal human subjects excrete glycine betaine at a constant rate. DESIGN AND METHODS Urine was collected from ten normal healthy male subjects for 14 days, during which fluid intake was systematically varied from <800 mL to >3 L per day. Glycine betaine, sorbitol and creatinine excretions were estimated per day and as millimole per mol creatinine. RESULTS The intrasubject SD of urine glycine betaine was 3.5 mmol/mol creatinine, and the intersubject SD 5.8 mmol/mol creatinine. The intrasubject SD of plasma glycine betaine was 10.2 mol/L and the intersubject SD 14.2 mol/L. Water load had little effect on glycine betaine excretion and plasma glycine betaine. After 12 years, excretions and plasma concentrations tended to parallel the initial results. CONCLUSIONS Normal subjects have consistent individual glycine betaine excretions that are not strongly influenced by urine volume. Abnormal excretions, or significant changes in excretion, can be interpreted as indicating a pathological process.
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Affiliation(s)
- Michael Lever
- Clinical Biochemistry Unit, Canterbury Health Laboratories, Christchurch School of Medicine and Health Sciences, Christchurch, New Zealand.
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Slow S, Garrow TA. Liver choline dehydrogenase and kidney betaine-homocysteine methyltransferase expression are not affected by methionine or choline intake in growing rats. J Nutr 2006; 136:2279-83. [PMID: 16920841 DOI: 10.1093/jn/136.9.2279] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Choline dehydrogenase (CHDH) and betaine-homocysteine methyltransferase (BHMT) are 2 enzymes involved in choline oxidation. BHMT is expressed at high levels in rat liver and its expression is regulated by dietary Met and choline. BHMT is also found in rat kidney, albeit in substantially lower amounts, but it is not known whether kidney BHMT expression is regulated by dietary Met or choline. Similarly, CHDH activity is highest in the liver and kidney, but the regulation of its expression by diet has not been thoroughly investigated. Sprague Dawley rats ( approximately 50 g) were fed, for 9 d in 2 x 3 factorial design (n = 8), an l-amino acid-defined diet varying in l-Met (0.125, 0.3, or 0.8%) and choline (0 or 25 mmol/kg diet). Liver and kidney BHMT and CHDH were assessed using enzymatic, Western blot, and real-time PCR analyses. Liver samples were also fixed for histological analysis. Liver BHMT activity was 1.3-fold higher in rats fed the Met deficient diet containing choline, which was reflected in corresponding increases in mRNA content and immunodetectable protein. Independent of dietary choline, supplemental Met increased hepatic BHMT activity approximately 30%. Kidney BHMT and liver CHDH expression were refractory to these diets. Some degree of fatty liver developed in all rats fed a choline-devoid diet, indicating that supplemental Met cannot completely compensate for the lack of dietary choline in growing rats.
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Affiliation(s)
- Sandy Slow
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana IL 61801, USA
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