Embryonic Gene Expression During Diabetic Embryopathy

糖尿病胚胎病期间的胚胎基因表达

• 批准号: 8205876
• 负责人: MARY R LOEKEN
• 金额: $ 40.65万
• 依托单位: JOSLIN DIABETES CENTER
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8205876
• 关键词: 5' -AMP-activated protein kinase; ATP Citrate (pro-S)-Lyase; Acetyl Coenzyme A; Acetylation; Aerobic; Affect; Antimycin A; Antioxidants; Binding; Biochemical; Biochemical Process; Cardiac; Cell Culture Techniques; Cell Respiration; Cells; Chromatin; Chromatin Structure; Citrates; Complex; Congenital Abnormality; CpG Islands; DNA Methylation; DNA Modification Process; DNA-Binding Proteins; Deacetylase; Defect; Development; Developmental Process; Diabetes Mellitus; Diabetic mother; Diabetic mouse; Differentiated Gene; Electron Transport Complex III; Embryo; Embryonic Development; Epigenetic Process; Failure; Free Radicals; Gene Expression; Genes; Genetic Transcription; Glucose; Heterogeneity; Histone Acetylation; Histone H3; Histones; Human; Hyperglycemia; Hypoxia; Knowledge; Lead; Link; Mediating; Mediator of activation protein; Metabolic; Metabolism; Methylation; Mitochondria; Modification; Molecular; Mothers; Mus; Neural Crest; Neural Tube Defects; Neural tube; Neurons; Organogenesis; Oxidation-Reduction; Oxidative Stress; Pathway interactions; Pattern; Pharmaceutical Preparations; Pregnancy; Procedures; Process; Production; RNA Interference; Reduced Glutathione; Regulation; Regulatory Element; Risk; Sampling; Signal Transduction; Source; Superoxides; Testing; Tissues; Transcription Initiation Site; Undifferentiated; Woman; base; cell type; chromatin modification; diabetic; diabetic embryopathy; embryo cell; embryonic stem cell; glucose metabolism; human embryonic stem cell; in vitro Model; in vivo Model; inhibitor/antagonist; innovation; malformation; maternal diabetes; neuroepithelium; non-diabetic; offspring; oxidation; prevent; research study; response

DESCRIPTION (provided by applicant): Congenital malformations are significantly increased in the offspring of women with pregestational diabetes. Oxidative stress, resulting from excessive glucose metabolism by the embryo, early during embryonic development, is responsible for these malformations. We have shown that oxidative stress inhibits expression of genes in the embryo that control essential developmental processes. In particular, expression of Pax3, which is required for neural tube and neural crest development, is significantly reduced in embryos of diabetic mice, and antioxidants block the inhibition of Pax3 as well as the associated neural tube and neural crest defects. While several of the biochemical processes leading to oxidative stress in embryos of diabetic mothers have been determined, it is not known how oxidative stress disrupts embryo gene expression. The central hypothesis in this proposal is that epigenetic regulation of Pax3 that is associated with increasing aerobic metabolism during early embryonic development is abrogated by oxidative stress resulting from maternal hyperglycemia. This hypothesis is based upon the recognition that fuel metabolism by the early embryo is highly glycolytic and becomes more oxidative as cells differentiate, and that genes that are expressed in the early embryo are dependent upon chromatin modifications. There are three Specific Aims: (1) Test whether oxidative stress blocks epigenetic modifications of the Pax3 transcription regulatory element that are necessary for differentiation-induced gene expression. (2) Test whether mediators of chromatin modifications, which are responsive to changes in oxidation or cellular redox status, change with differentiation, whether they are inhibited by oxidative stress, and whether they regulate Pax3 expression. (3) Test whether AMP-activated protein kinase (AMPK), which is activated in embryos and embryonic stem cells (ESC) in response to hypoxia and oxidative stress, mediates the effects of oxidative stress to block differentiation- induced chromatin modifications. Our approach is to study histone methylation and acetylation and DNA methylation in ESC, and Pax3 expression in mouse embryos and in ESC. ESC will be induced to differentiate into neuronal precursors, and oxidative stress will be induced in ESC or embryos, and the effects of stimulating or inhibiting pathways that potentially modify chromatin in response to oxidative stress will be examined. The proposed study is significant because it will determine the mechanisms by which abnormal fuel metabolism caused by maternal diabetes disrupts the activation of embryonic gene expression, thereby leading to malformations. This knowledge may lead to new strategies to normalize embryo gene expression during diabetic pregnancy. This proposal is innovative because the concept that early embryonic gene expression is developmentally regulated by signals generated by fuel metabolism that alter chromatin structure has not previously been investigated. PUBLIC HEALTH RELEVANCE: The risk for congenital malformation is significantly increased when a mother has diabetes (either type 1 or type 2). In this proposal, we will test the hypothesis that free radicals, produced by excess glucose metabolism, interfere with modifications of DNA and of DNA-binding proteins, called histones, which are necessary for proper activation of embryo gene expression. The results obtained from these experiments may lead to the development of new treatments to prevent congenital malformations during diabetic pregnancy.

描述（由申请人提供）：患有孕育糖尿病的妇女后代的先天性畸形大大增加。胚胎发育期间早期，胚胎过量的葡萄糖代谢产生的氧化应激是造成这些畸形的原因。我们已经表明，氧化应激抑制了控制基本发育过程的胚胎中基因的表达。特别是，神经管和神经rest发育所需的PAX3的表达在糖尿病小鼠的胚胎中显着降低，抗氧化剂阻止了PAX3的抑制以及相关的神经管和神经犯罪缺陷。尽管已经确定了导致糖尿病母亲胚胎中氧化应激的几种生化过程，但尚不知道氧化应激如何破坏胚胎基因表达。该提案中的中心假设是，与胚胎高血糖产生的氧化应激消除了与早期胚胎发育期间有氧代谢相关的PAX3的表观遗传调节。该假设是基于以下认识：早期胚胎的燃料代谢是高糖酵解的，并且随着细胞的分化而变得更加氧化，并且在早期胚胎中表达的基因取决于染色质的修饰。有三个特定的目的：（1）测试氧化应激是否阻止了分化诱导的基因表达所必需的PAX3转录调节元件的表观遗传修饰。 （2）测试染色质修饰的介体是否反应氧化或细胞氧化还原状态的变化，随着分化的变化，是否受到氧化应激的抑制，以及它们是否调节PAX3表达。 （3）测试AMP激活的蛋白激酶（AMPK）是否在响应缺氧和氧化应激的胚胎和胚胎干细胞（ESC）中激活的AMP激活蛋白激酶（AMPK）是否介导了氧化应激以阻断分化诱导的染色质修饰的作用。我们的方法是研究ESC中的组蛋白甲基化，乙酰化和DNA甲基化，以及小鼠胚胎和ESC中的PAX3表达。 ESC将被诱导分化为神经元前体，并在ESC或胚胎中诱导氧化应激，并将检查刺激或抑制途径的效果，这些途径可能会检查潜在地对氧化应激的染色质修饰。拟议的研究很重要，因为它将确定由母体糖尿病引起的异常燃料代谢的机制，破坏了胚胎基因表达的激活，从而导致畸形。这些知识可能会导致新的策略，以使糖尿病妊娠期间胚胎基因表达正常化。该提议具有创新性，因为早期胚胎基因表达在发育中受到燃料代谢产生的信号的调节的概念，以前尚未研究过改变染色质结构的概念。 公共卫生相关性：母亲患有糖尿病（1型或2型）时，先天性畸形的风险大大增加。在该提案中，我们将检验以下假设：由多余的葡萄糖代谢产生的自由基干扰DNA的修饰和DNA结合蛋白（称为组蛋白），这对于适当激活胚胎基因表达是必不可少的。从这些实验中获得的结果可能会导致开发新的治疗方法，以防止糖尿病怀孕期间先天性畸形。