Epigenomic regulation of metabolism in muscle by circadian clock and environment

描述(由Candiate提供)：目前的研究是研究表观基因组修饰物组蛋白去乙酰基酶3(HDAC3)如何调节骨骼肌中的碳水化合物代谢和胰岛素敏感性，以响应内部生物钟或外部饮食因素。我开发了一种新的小鼠模型，其HDAC3特异性地在骨骼肌中耗尽，并发现小鼠表现出代谢昼夜节律基因的表达中断，并加剧了由高脂饮食(HFD)诱导的葡萄糖耐受。在指导阶段，我将在全基因组表观基因组学方法方面获得新的专业知识，这些方法在我的导师的实验室中已经很好地建立起来了。我还将通过与宾夕法尼亚大学的其他实验室和核心设施合作，获得肌肉生理学、代谢流量分析和代谢组学方法方面的额外知识。我建议在独立阶段继续的研究是研究HDAC3在运动耐力、燃料选择和效率以及骨骼肌脂和氨基酸代谢方面的作用。我们发现，没有肌肉HDAC3的小鼠运动耐力有令人惊讶的提高，这与燃料偏好从碳水化合物转向脂肪有关。我将在运动动物和分离的原代心肌细胞中，通过脂类、酮体和氨基酸分解代谢(包括无性嘌呤核苷酸循环)来表征线粒体功能和跟踪代谢通量，其中敲除实验将测试观察到的燃料选择和提高燃料效率所需的特定HDAC3靶基因。独立后，我未来的职业目标是破译骨骼肌对运动的兴奋反应所依据的表观遗传学机制。运动有益于健康的许多方面，特别是在肥胖和糖尿病的背景下。我的一般假设是，表观基因组学机制是运动诱导有益的代谢重塑的基础。我将使用全基因组方法和代谢组学方法来全面描述运动引起的骨骼肌转录组和表观基因组的变化。据我所知，这是有史以来第一次在全基因组范围内分析运动引起的表观基因组变化。这种无偏见的方法将产生全面的数据集，从中数据挖掘和基序分析将产生关于新的转录网络的新假设，这些网络对运动做出反应。然后将使用生物化学方法和代谢流量分析来验证这些假设，随后将开发遗传动物模型和生理学研究。总而言之，这些方法将产生有初步数据支持的可验证假说，这对于成功竞争未来的融资机会至关重要。

DESCRIPTION (provided by candidate): The current research is to study how epigenomic modifier histone deacetylase 3 (HDAC3) regulates carbohydrates metabolism and insulin sensitivity in skeletal muscle in response to either the internal circadian clock or the external dietary factor. I have developed a novel mouse model with HDAC3 specifically depleted in skeletal muscle, and have found that the mice display disrupted metabolic circadian gene expression and exacerbated glucose intolerance that is induced by high fat diet (HFD). During the mentored phase, I will gain new expertise in genome-wide epigenomic approaches that are well established in my mentor's laboratory. I will also gain additional knowledge in muscle physiology, metabolic flux analysis, and metabolomics methods through collaboration with other laboratories and core facilities at University of Pennsylvania. The research that I propose to continue in the independent phase is to study HDAC3 in exercise endurance, fuel selection and efficiency, as well as lipid and amino acid metabolism in skeletal muscle. We have found that mice without muscular HDAC3 have surprisingly improved exercise endurance associated with a switch in fuel preference from carbohydrates towards lipid. I will characterize mitochondrial function and trace metabolic fluxes through lipid, ketone bodies, and amino acids catabolism, including the anaplerotic purine nucleotide cycle, in exercising animals as well as in isolated primary myocytes, where knockdown experiments will test the requirement of specific HDAC3 target genes for the observed fuel selection and enhanced fuel efficiency. My future career goal after independence is to decipher the epigenomic mechanism that underlies hormetic response to physical exercise in skeletal muscle. Exercise is beneficial to many aspects of health, especially in the context of obesity and diabetes. My general hypothesis is that epigenomic mechanisms underlie exercise- induced beneficial metabolic remodeling. I will comprehensively characterize exercise-induced changes in skeletal muscle transcriptome and epigenome using genome-wide methods and metabolomics approaches. This is the first endeavor ever, as far as I know, to analyze exercise-induced epigenomic changes in a genome-wide scale. This unbiased method will produce comprehensive datasets, from which data mining and motif analysis will generate new hypotheses regarding novel transcription networks that respond to exercise. Biochemistry methods and metabolic flux analysis will then be used to validate these hypotheses, followed by development of genetic animal models and physiology studies. Together, these approaches will generate testable hypothesis backed up by preliminary data, which is essential for successful competition for future funding opportunities.