HMGCS2/FOXO3a乙酰化在高脂膳食诱导肾功能受损中的作用

Western-style Diet with characteristics of high-fat and high-calorie foods is one of key risk factors in the development of kidney dysfunction. We have found that tea polyphenols can up-regulate the expression of kidney HMGCS2,a key enzyme of ketone body synthesis, in high-fat-fed rats and have an association with anti-oxidantive ability in kidney with mechanism unknown. We here propose the route of enhanced renal anti-oxidative ability with up-regulation of mitochondrial anti-oxidative proteins via decreased deacetylation level of FOXO3a by HMGCS2 controlled ketone body synthesis. Present project will explore:1) in animal studies, the effect of high-fat diet and tea polyphenols on the expression and activity of HMGCS2 and the level of ketone bodies in the rat kidney, the role of HMGCS2 and ketone bodies in the antioxidant protection with focus on histone deacetylases\FOXO3a acetylation\ mitochondrial anti-oxidative protein expression; 2) in vitro, the changes in the level of oxidative stress and the expressions and activities of relevant enzymes in oxidative damage model established in HEK293, the role of ketone bodies and tea polyphenols, and the mechanisms of HMGCS2 induced ketone bodies.

高脂高能量为特征的西方膳食是肾脏功能受损的主要危险因素之一，我们前期研究发现茶多酚上调高脂饲料喂养大鼠肾脏线粒体酮体产生关键酶HMGCS2的表达,且与肾脏抗氧化保护作用有关，但机制不明。本项目在此基础上提出肾组织HMGCS2（产生酮体）影响FOXO3a乙酰化，进而调控线粒体抗氧化蛋白的表达，提升肾脏抗氧化能力的设想，并拟加以研究。 本项目：1）动物实验，观察高脂膳食及茶多酚对大鼠肾组织HMGCS2的表达、活性以及酮体浓度的影响，分析对组蛋白去乙酰化酶\FOXO3a\线粒体抗氧化蛋白的影响，探究可能的抗氧化机制。2）体外培养HEK293细胞，构建细胞氧化损伤模型，观察茶多酚诱导及酮体对细胞氧化应激水平及上述通路各环节关键分子的影响，以探究酮体抗氧化作用及机制。

高脂膳食能导致肾脏受损，然而生酮膳食，一种高脂肪低碳水化合物膳食，却可以逆转糖尿病肾脏损伤，但是具体机制尚不明确。我们前期的研究结果显示绿茶多酚（GTPs）干预可以上调高脂膳食大鼠肾脏生酮关键酶（HMGCS2）的表达。因此，本课题拟研究生酮作用是否可以介导绿茶多酚对高脂膳食大鼠肾脏的保护作用及其具体机制。.1.体内实验显示：（1）绿茶多酚干预可以降低高脂膳食大鼠肾脏氧化应激水平及肾功能的损伤；（2）绿茶多酚能上调高脂膳食大鼠肾脏HMGCS2表达水平、酮体水平、SIRT3表达及活性；.2.体外实验显示：（1）绿茶多酚干预能上调HEK293细胞（转染质粒pcDNA HMGCS2）HMGCS2和 SIRT3蛋白表达水平；（2）0.1mM过氧化氢存在条件下，转染HMGCS2质粒细胞，乙酰化MnSOD（acetyl K122）/总MnSOD比率及4HNE水平降低。.绿茶多酚可以通过上调高脂膳食大鼠肾脏SIRT3和HMGCS2表达，并通过HMGCS2途径提高SIRT3活性，降低氧化应激水平，发挥肾脏保护作用。.针对于目前我国膳食模式西方化，本研究结果对预防慢性肾病有重要的应用价值，同时也为临床慢性肾病的治疗提供理论依据