Regulation of kidney nutrient metabolism by SIRT5

项目摘要(摘要) 糖尿病的发病率和死亡率主要是由其主要并发症引起的，这些并发症包括 糖尿病肾病(DKD)。尽管在实验模型中存在大量关于疾病机制的数据， 人类DKD的发病机制尚不清楚，但高血糖是DKD的主要危险因素。 我们的研究导致了一种新的范式，即改变糖尿病肾脏的营养利用和流量 DKD的一个关键特性。利用BKS db/db糖尿病小鼠模型，我们研究了糖尿病小鼠碳水化合物和 肾皮质中的脂类代谢。使用转录组学、代谢组学和代谢流的系统方法 分析发现，肾脏中的葡萄糖和脂肪酸代谢增加。养分利用率的提高 未导致ATP/ADP比值增加，并伴有线粒体功能障碍。 此外，我们观察到蛋白质的赖氨酸-丙二酸丙二酸化(一个可以改变酶活性的过程)减少。 在糖尿病肾脏中，Sirtuin 5(SIRT 5)活性增加与Sirtuin 5(SIRT 5)活性相关，SIRT 5是一种已知的去丙氨酸化介质。 这些观察结果构成了这一提议的基础，该提议试图测试SIRT5在调节改变的过程中的作用 糖尿病肾脏中的代谢流量。我们假设，丙二酸化的减少是由 在db/db糖尿病肾脏中观察到的sirt 5有助于增加营养通量。使用SIRT 5敲门- 用高脂饮食和链脲佐菌素治疗糖尿病小鼠，我们的计划是：1)研究它们的影响 糖尿病小鼠肾皮质SIRT-5葡萄糖缺乏和脂肪酸代谢通量的研究，2)确定靶点 肾脏SIRT-5缺乏症患者肾脏丙二酸化的差异及丙二酸化对靶点的影响 糖尿病肾皮质代谢酶活性；3)评价SIRT-5赖氨酸丙二酸化的作用 糖尿病条件下的靶向代谢酶。这些研究将对阐明SIRT5的作用至关重要 糖尿病患者肾脏中营养物质的利用。

PROJECT SUMMARY (ABSTRACT) The morbidity and mortality of diabetes mellitus occurs largely from its major complications, which include diabetic kidney disease (DKD). Although extensive data exist on disease mechanisms in experimental models, the pathogenesis of human DKD remains unclear except that hyperglycemia is a major risk factor for DKD. Our studies have led to an emerging paradigm that altered nutrient utilization and flux in the diabetic kidney is a key feature of DKD. Utilizing BKS db/db diabetic mouse model, we investigated changes in carbohydrate and lipid metabolism in kidney cortex. A systems approach using transcriptomics, metabolomics, and metabolic flux analysis identified increased glucose and fatty acid metabolism in the kidney. The increased nutrient utilization did not result in an increased ATP/ADP ratio, and was accompanied by mitochondrial dysfunction. Furthermore, we observed decreased lysine-malonylation of proteins (a process that can alter enzyme activity) in diabetic kidney associated with increased Sirtuin 5 (SIRT 5) activity, a known mediator of demalonylation. These observations form the basis of this proposal that seeks to test the role of SIRT5 in mediating altered metabolic flux in the diabetic kidney. We hypothesize that the decreased malonylation, which is regulated by SIRT 5, observed in the db/db diabetic kidney contributes to the increased nutrient flux. Using SIRT 5 knock- out mice made diabetic with high-fat diet and streptozotocin treatments, our plan is to: 1) investigate the effect of SIRT 5 deficiency in glucose and fatty-acid metabolic flux in kidney cortex in diabetic mice, 2) identify targets of differential malonylation with SIRT 5 deficiency in kidney and assess for the effect of malonylation on target metabolic enzyme activity in diabetic kidney cortex, and 3) evaluate effect of lysine malonylation of SIRT 5 target metabolic enzymes under diabetic conditions. These studies will be pivotal in clarifying the role of SIRT5 in nutrient utilization in the kidney in diabetic states.