Mesoderm specific transcript and adipose tissue expansion

中胚层特异性转录和脂肪组织扩张

• 批准号: 9981735
• 负责人: Robert A Koza
• 金额: $ 44.17万
• 依托单位: MAINEHEALTH
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-22 至 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9981735
• 关键词: Acyltransferase; Adipocytes; Adipose tissue; Biological Assay; Cell Nucleus; Cells; Complex; Confocal Microscopy; Controlled Environment; DNA; DNA analysis; Data; Development; Diet; Endoplasmic Reticulum; Environment; Epigenetic Process; Epoxide hydrolase; Epoxy Compounds; Fatty acid glycerol esters; Fluorescence Resonance Energy Transfer; Genes; Genetic; Genetic Predisposition to Disease; Genome; Goals; Heritability; High Fat Diet; Homeostasis; Hydrolase; Impairment; In Vitro; Inbreeding; Individual; Inflammation; Knockout Mice; Laboratories; Link; Lipase; Lipids; Liposomes; Mediating; Membrane; Membrane Proteins; Mesenchymal Stem Cells; Mesoderm; Metabolic; Metabolic Diseases; Metabolic dysfunction; Modeling; Modification; Molecular; Mouse Strains; Mus; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Pathway interactions; Population; Predisposition; Production; Protein Family; Proteins; RNA; Regulation; Serine Protease; Suggestion; System; Testing; Time; Tissue Expansion; Transcript; Transcription Coactivator; Translations; Triad Acrylic Resin; Triglycerides; Tyrosine; Variant; alpha-glycerophosphoric acid; base; blood glucose regulation; epigenomics; gene environment interaction; glucose tolerance; imprint; improved; in vivo; insulin sensitivity; inter-individual variation; knock-down; novel; obesity development; obesity treatment; overexpression; promoter; small hairpin RNA

The rising global rate of obesity is caused by complex interactions between genetic, environmental and epigenetic factors. Gene-environment interactions are recognized as important for the development of obesity; however, the contribution of epigenetic-based mechanisms is not well defined. Using a diet-induced obesity susceptible genetically identical population of mice raised in controlled environmental conditions, we were able to identify potential epigenetic determinants of obesity. One of the genes that was identified, the paternally-expressed gene mesoderm specific transcript (Mest), was shown to have highly variable expression in white adipose tissue (WAT) and was positively associated with WAT expansion. Mouse strains developed by our laboratory with global and adipose tissue-specific inactivation of Mest showed that its inactivation is able to reduce high fat diet-mediated adipose tissue expansion and WAT inflammation, and improve glucose tolerance and insulin sensitivity. The stability of inter-individual variations of Mest expression in WAT is predictive for the development of obesity and suggestive of a `heritable' epigenetic mechanism for its regulation. Because Mest is coordinately regulated with the transcriptional activator Kruppel-like-factor 14 (Klf14) which resides ~200 kb downstream of the Mest locus on mouse Chr 6, it is possible that both genes are regulated by a common epigenetic pathway during metabolic imbalance. One of the goals of this proposal is to test whether Mest is regulated by an epigenetically heritable regulatory network that controls its expression in adipose tissue with dietary obesity (Aim 1). MEST belongs to the α/β hydrolase family of proteins which has a diversity of catalytic functions. Based on homology with similar proteins, MEST may function as an acyltransferase, lipase or epoxide hydrolase. We showed that MEST is localized within the endoplasmic reticulum (ER) membrane of adipocytes and co-localizes with lipid droplet surface proteins at ER-lipid droplet contact points. In vitro studies using mesenchymal progenitor cells derived from control or Mest-null mice, in concert with shRNA knockdown of Gpat4 suggest that MEST either possesses endogenous GPAT-like catalytic activity, or is an allosteric regulator of GPAT function. A second goal of this proposal will be to define how MEST functions to facilitate lipid accumulation in adipocytes (Aim 2). The aims of this proposal test our hypothesis that an epigenetic mechanism common to both Mest and Klf14 controls their expression in adipose tissue, and that inter-individual susceptibility for the development of obesity and impaired glucose homeostasis is caused by MEST-facilitated lipid accumulation in adipocytes via modulation of GPAT or EH activity at the ER-lipid droplet interface.

全球肥胖率上升是由遗传，环境和表观遗传因素之间的复杂相互作用引起的。基因环境相互作用被认为对肥胖的发展很重要。但是，基于表观遗传的机制的贡献尚未很好地定义。使用饮食引起的肥胖症在受控环境条件下提出的小鼠的遗传相同种群，我们能够鉴定肥胖的潜在表观遗传决定剂。被鉴定出的基因之一，含父表达的基因中胚层特异性转录本（MEST），在白色脂肪组织（WAT）中具有高度可变的表达，并且与WAT膨胀呈正相关。我们的实验室通过全球和脂肪组织特异性灭活发育的小鼠菌株表明，其失活能够减少高脂肪饮食介导的脂肪组织的扩张和水分注射，并提高葡萄糖耐受性和胰岛素敏感性。 WAT中最高表达的个体间变化的稳定性可预测肥胖的发展，并暗示了其调节的“可遗传”表观遗传机制。由于Mest与转录激活剂Kruppel样因子14（KLF14）协调调节，其在小鼠ChR 6上的含量约为200 kb，因此在代谢不平衡期间，这两个基因都可能受到常见的表观遗传途径的调节。该提案的目标之一是测试MEST是否受到表观遗传遗传的调节网络的调节，该法规控制其在饮食肥胖症中控制其在脂肪组织中的表达（AIM 1）。 Mest属于具有多种催化功能的蛋白质的α/β水解酶家族。基于与类似蛋白质的同源性，Mest可能起到Aycyltransferase，脂肪酶或环氧水解酶的作用。我们表明，MEST位于脂肪细胞的内质网（ER）膜中，并与ER-脂质液滴接触点的脂质液滴表面蛋白共定位。使用源自对照或最无效小鼠的间充质祖细胞的体外研究，与GPAT4的shRNA敲低表明，Mest具有内源性GPAT样催化活性，或者是GPAT功能的变构调节剂。该提案的第二个目标是定义如何促进脂肪细胞中脂质积累的功能（AIM 2）。该提案的目的检验了我们的假设，即MEST和KLF14共有的表观遗传机制可以控制其在脂肪组织中的表达，并且由于脂肪细胞在脂肪细胞中的脂肪细胞的积累而导致的脂肪效果掉落或EH-eh-eh-eh er Gpat At er Gpat at gpat at gpate at er gpat at gpatat at gpat at gpat at gpat at er gpat at pat at gpat at gpat at gpat at gpatat at gpat ater erh er gpat at gpat at er gpat at gpat at gpat at gpat at er er gpat at er gpat at er gpat at er的易受依赖性的敏感性。