The effect of mitochondrial CoA degradation on glucose and fatty acid metabolism

项目总结/摘要 线粒体代谢依赖于辅酶A（CoA）来支持脂肪酸等代谢过程 氧化、生酮和糖异生。CoA的积累导致脂肪酸氧化增加， 从而导致糖尿病的发生。骨骼肌钝性线粒体中CoA水平异常升高 通过降低电子传递链复合物I的活性来合成ATP。尽管有这些证据 将CoA增加与代谢失调联系起来，线粒体内调节CoA水平的机制 目前尚不清楚。Nudt 8是一个未知的Nutriol水解酶超家族成员。这种蛋白质 由于其与Nudt 7的高度序列同源性，已被注释为潜在的CoA降解酶， 先前表征的CoA二磷酸水解酶，其存在于过氧化物酶体中。我们的初步数据显示 Nudt 8特异性降解游离CoA和CoA硫酯。此外，Nudt 8定位于线粒体， 并在高氧化性组织如心脏、肾脏、肝脏、棕色脂肪组织和肌肉中表达。 Nudt 8的CoA降解活性，加上其定位于线粒体，表明了这一作用 酶在线粒体辅酶A水平的调节，从而，代谢。该研究将利用 腺相关病毒实现Nudt 8在肝脏中的过表达，然后分析其对肝脏的影响。 线粒体CoA库的大小和组成，以及对线粒体脂肪酸和葡萄糖代谢的影响。 此外，调节Nudt 8表达和活性的机制将被阐明。 拟议的研究将在可供使用的优秀研究设施的支持下完成， 申请人，并与生物化学系内外的其他研究人员合作，在西 弗吉尼亚大学。高度协作的环境，结合个性化的培训计划，将允许 申请人获得广泛的技术技能，并发展批判性思维能力，这两者都 是受训者成长为成功科学家的关键。申请人将参加严格的课程 工作和口头报告;这些做法将提供一个广泛的知识基础代谢， 提高申请人表达其科学思想的能力。总的来说， 研究和培训计划将培养出一位全面发展的科学家，以及对该法规的宝贵见解 线粒体辅酶A库和靶向Nudt 8纠正线粒体辅酶A库失调的潜力 它是多种代谢性疾病的基础。

PROJECT SUMMARY/ABSTRACT Mitochondrial metabolism is dependent on coenzyme A (CoA) to support metabolic processes like fatty acid oxidation, ketogenesis, and gluconeogenesis. Accumulation of CoA results in increased fatty acid oxidation, which drives gluconeogenesis in diabetes. Abnormally high CoA levels in skeletal muscle blunt mitochondrial ATP synthesis by decreasing the activity of complex I of the electron transport chain. Despite this evidence linking increased CoA to metabolic dysregulation, the mechanisms regulating CoA levels within the mitochondria are currently unknown. Nudt8 is an uncharacterized member of the Nudix hydrolase superfamily. This protein has been annotated as a potential CoA-degrading enzyme due to its high sequence homology to Nudt7, a previously characterized CoA diphosphohydrolase that resides in the peroxisomes. Our preliminary data show that Nudt8 specifically degrades free CoA and CoA thioesters. Additionally, Nudt8 localizes to the mitochondria and is expressed in highly oxidative tissues such as the heart, kidney, liver, brown adipose tissue, and muscle. The CoA-degrading activity of Nudt8, coupled with its localization to the mitochondria, suggests a role for this enzyme in the regulation of mitochondrial CoA levels and thus, metabolism. The proposed research will utilize adeno-associated virus to achieve over-expression of Nudt8 in the liver, followed by analysis of its effects on mitochondrial CoA pool size and composition, and on the mitochondrial metabolism of fatty acids and glucose. Additionally, mechanisms regulating Nudt8 expression and activity will be elucidated. The proposed research will be completed with the support of the excellent research facilities available to the applicant and in collaboration with other investigators within and outside the Department of Biochemistry at West Virginia University. The highly collaborative environment, combined with a personalized training plan, will allow the applicant to acquire skills in a broad range of techniques and to develop critical thinking skills, both of which are essential for a trainee to develop into a successful scientist. The applicant will participate in rigorous course work and oral presentations; these practices will provide an extensive knowledge base in metabolism and enhance the ability of the applicant to communicate his scientific ideas. Overall, the proposed combination of research and training plans will produce a well-rounded scientist as well as valuable insight into the regulation of the mitochondrial CoA pool and potential of targeting Nudt8 to correct the dysregulated mitochondrial metabolism that underlies a variety of metabolic diseases.