Folate and S-adenosyimethionine in Methyl Group and One-carbon Metabolism

甲基中的叶酸和S-腺苷甲硫氨酸与一碳代谢

基本信息

批准号：
8215729
负责人：
CONRAD WAGNER
金额：
$ 33.25万
依托单位：
VANDERBILT UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-02-01 至 2014-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8215729
关键词：
Affect Age Age-Months Amines Amino Acids Animal Feed Animals Appearance Binding Carbon Cells Child Cirrhosis Code Coenzymes Collection Creatine Creatinine DNA DNA Methylation DNA biosynthesis Data Development Diet Enzyme Inhibitor Drugs Enzyme Inhibitors Enzymes Epigenetic Process Exocrine pancreas Family Fatty Liver Fibrosis Folate Folic Acid Deficiency Formaldehyde Gene Expression Gene Expression Regulation Gene Targeting Genes Genomics Glycine Goals Health Hepatic Tissue Histologic Histology Histones Homocysteine Homocystine Human Hypermethylation Immunohistochemistry In Vitro Inflammation Intestinal Mucosa Kidney Knock-out Knockout Mice Link Liver Liver diseases Malignant Neoplasms Malignant neoplasm of liver Measures Mediating Metabolism Methionine Methionine Metabolism Pathway Methods Methylation Methyltransferase Missense Mutation Modeling Mus Mutation Niacinamide Pancreas Pathology Pathway interactions Plasma Play Primary carcinoma of the liver cells Process Production Promoter Regions Prostate Proteins Purines Reaction Regulation Role S-Adenosylhomocysteine S-Adenosylmethionine Sarcosine Serum Severities Steatohepatitis Submandibular gland Testing Tetrahydrofolates Thymine Time Tissues Urine animal tissue betaine-homocysteine methyltransferase enzyme activity feeding folate-binding protein folic acid metabolism glycine N-methyltransferase guanidinoacetate in vivo indexing inhibitor/antagonist methyl group mouse model oxidation pancreatic juice prevent promoter purine

项目摘要

DESCRIPTION (provided by applicant): Regulation of methylation is intimately associated with folate metabolism. These two metabolic processes are connected by the enzyme, glycine N-methyltransferase, which is abundant in liver, exocrine pancreas and prostate as well as in kidney and intestinal mucosa in lower amounts. It carries out the methylation of glycine by S-adenosylmethionine (AdoMet) to form N-methylglycine and S-adenosylhomocysteine (AdoHcy). The function of the enzyme is believed to be regulation of the ratio of AdoMet to AdoHcy. AdoMet is the major do- nor of methyl groups and the AdoMet/AdoHcy ratio an index of the methylating capacity of the cell. The enzyme also tightly binds 5-methyl-tetrahydrofolate pentaglutamate in vivo and in vitro, which acts as an inhibitor of the enzyme. This links the availability of preformed methyl groups, as methionine, to the de novo synthesis of methyl groups via folate-mediated reactions. We developed a glycine N-methyltransferase knockout mouse that has very high levels of S-adenosylmethionine in the livers and plasma compared to WT mice. Preliminary data showed that liver DNA is not globally hypermethylated. These -/- mice spontaneously develop fatty liver. Our First Hypothesis is that extra-hepatic tissues from -/- animals with high levels of glycine N- methyltransferase will also have abnormal histology and elevated AdoMet. Our First Specific Aim is to ex- amine histology and measure methionine metabolites in tissues from WT, and -/- mice. Our Second Hy- pothesis is that promoter regions of genes will be hypermethylated affecting the epigenetic expression of key proteins. Our second Specific Aim is to measure DNA for global methylation and the promoter regions of genes involved in the development of steatohepatitis and methionine metabolism in tissue from WT and mice. Glycine N-methyltransferase is most abundant in exocrine tissue. Our Third Hypothesis is that glycine N-methyltransferase is important in exocrine secretion and our Third Specific Aim is to measure exocrine se- cretion in WT and -/- mice. The most abundant folate coenzyme in liver is 5-methyltetrahydrofolate. Most of the folate in the liver is tightly bound to glycine N-methyltransferase. Our Fourth Hypothesis is that in the absence of this protein the different forms of folate will be redistributed and result in alterations in folate-mediated reac- tions. Our Fourth Specific Aim is to measure the distribution of the various forms of folate in liver, pancreas and prostate of WT and -/- mice and also whether it is changed in folate deficiency. The levels of AdoMet are very high in -/- animals suggesting that proteins may be overmethylated. Our Fifth Hypothesis is that his- tones may be hypermethylated in -/- animals. Our Fifth Specific Aim is to examine the methylation of histones in WT and -/- mice. Our Sixth Hypothesis is that it is possible to reduce the high levels of AdoMet in tissues by administration of compounds that serve as acceptors of methyl groups and reduce the severity of liver dis- ease in -/- mice. Our Sixth Specific Aim is to determine whether administration of nicotinamide or guanidi- noacetate will do this. PUBLIC HEALTH RELEVANCE: This proposal "Folate and S-adenosylmethionine in Methyl Group and One-carbon Metabolism" deals with the effects of the loss of the enzyme, glycine N-methyltransferase, a major enzyme in liver, pancreas and the prostate gland. We have discovered mutations of this enzyme in several children that result in moderate liver damage and have developed a mouse model that has a complete absence of glycine N-methyltransferase that progresses to severe liver disease as they get older. One of the goals of this proposal is to evaluate the use of several common natural compounds for their ability to diminish the development of liver damage in this mouse model thus raising the possibility of treating humans with defective glycine N-methyltransferase and prevent serious liver damage.

描述（由申请人提供）：甲基化的调节与叶酸代谢密切相关。这两个代谢过程是通过酶N-甲基转移酶甘氨酸N-甲基转移酶连接的，该酶在肝脏，外分泌胰腺和前列腺以及肾脏和肠粘膜中含量较低。它通过S-腺苷甲硫代（ADOMEM）进行甘氨酸的甲基化，形成N-甲基甘氨酸和S-腺苷羟瘤半胱氨酸（Adohcy）。据信酶的功能是ADOMET与Adohcy之比的调节。 ADOMET是甲基的主要或ADOMET/ADOHCY比，是细胞的甲基化能力的指数。该酶还紧密地结合了体内和体外的5-甲基四氢叶酸戊二酸戊二酸戊二酸戊二酸酯，后者充当酶的抑制剂。这将预先形成的甲基（如蛋氨酸）的可用性与通过叶酸介导的反应从头合成的甲基合成。与WT小鼠相比，我们开发了一种甘氨酸N-甲基转移酶基因敲除小鼠，该小鼠在肝脏和血浆中具有很高的S-腺苷硫氨酸。初步数据表明，肝脏DNA不是全球性高甲基化的。这些 - / - 小鼠自发发展脂肪肝。我们的第一个假设是，来自甘氨酸N-甲基转移酶的 - / - 动物的肝外组织也将具有异常的组织学和升高的ADOMET。我们的第一个具体目的是检验胺基学并测量来自WT的组织中的蛋氨酸代谢产物和 - / - 小鼠。我们的第二个方法是，基因的启动子区域将是高甲基化的，影响关键蛋白的表观遗传表达。我们的第二个具体目的是测量与WT和小鼠组织中脂肪性肝炎和蛋氨酸代谢发展有关的基因和蛋氨酸代谢的基因的启动子区域的DNA。甘氨酸N-甲基转移酶在外分泌组织中最丰富。我们的第三个假设是，甘氨酸N-甲基转移酶在外分泌分泌中很重要，我们的第三个具体目的是测量WT和 - / - 小鼠中的外分泌症。肝脏中最丰富的叶酸辅酶是5-甲基四氢叶酸。肝脏中的大多数叶酸都与甘氨酸N-甲基转移酶紧密结合。我们的第四个假设是，在没有该蛋白质的情况下，将重新分布不同形式的叶酸，并导致叶酸介导的反应改变。我们的第四个具体目的是测量叶酸，胰腺和 - wt和 - / - 小鼠的各种形式的叶酸的分布，以及它是否在叶酸缺乏方面发生了变化。 - / - 动物的ADOMET水平很高，表明蛋白质可能过度甲基化。我们的第五个假设是 - 在 - / - 动物中可能是甲基化的。我们的第五个具体目的是检查WT和 - / - 小鼠中组蛋白的甲基化。我们的第六个假设是，可以通过给予用作甲基受体的化合物并降低 - / - 小鼠中肝脏的严重程度来降低组织中的高水平ADOMET。我们的第六个具体目的是确定烟酰胺或鸟甲酸的给药是否会这样做。公共卫生相关性：该提案“甲基组中的叶酸和s-腺苷甲硫代和单碳代谢”涉及酶丧失酶，甘氨酸N-甲基转移酶的损失的影响，甘氨酸N-甲基转移酶，肝脏，胰腺和前列腺腺体中的主要酶。我们已经在几个儿童中发现了这种酶的突变，这些突变导致中度肝脏损害，并开发出一种小鼠模型，该模型完全没有甘氨酸N-甲基转移酶，随着年龄的增长，它们会发展为严重的肝病。该提案的目标之一是评估使用几种常见的天然化合物，以减少该小鼠模型中肝脏损伤发展的能力，从而增加了患有甘氨酸N-甲基转移酶缺陷并防止严重肝损害的人类的可能性。