缺血再灌注性急性肾损伤中Klotho水平与炎症的关系及作用机制研究

Acute kidney injury is a common clinical critical disease, lack of effective therapies. Klotho is an "anti-aging" protein expressed in renal tubular epithelial cells. There are two ways regulation between Klotho and inflammation. Our previous study found that, Klotho expression in renal was significantly decreased in AKI and associated with inflammation. Supplement of Klotho could effectively protect from renal injury and inflammation, suggesting that Klotho plays an important role in the development of inflammation in AKI. NF-kB is a key transcription factor in the regulation of cytokine expression and an important target of AKI. In the non kidney disease, Klotho could inhibit the phosphorylation of PI3K/Akt,then further mediat NF-kB pathway activation. In this study, we try to identify the relationship of Klotho level with inflammation and renal injury in ischemic reperfusion AKI. We try to determine whether Klotho could anti inflammation by inhibiting the activation of PI3K/Akt，then inhibiting RelA(Ser)536 phosphorylation and further inhibiting NF-kB DNA binding and translocation by means of gene regulation. This study would provide the theoretical information for the prevention and treatment of AKI by regulating Klotho expression in the future.

急性肾损伤（AKI）是临床常见危重病，尚缺乏有效治疗手段。Klotho是一种表达在肾小管上皮细胞的"抗衰老"蛋白，与炎症之间存在双向调节关系。我们前期研究发现，AKI时肾脏Klotho水平显著降低，且伴随炎症的发生。而补充Klotho蛋白可以有效改善肾功能和炎症，提示Klotho在AKI后肾脏炎症的发生发展中起着重要的作用。NF-κB是调控炎症细胞因子表达的关键转录因子，也是AKI的重要靶点。在非肾病中，Klotho可以抑制PI3K/Akt的磷酸化，进一步介导NF-κB信号通路活化。本课题拟通过体内外研究明确Klotho在肾缺血再灌注AKI时的变化及其与炎症和肾损害的关系，采用基因调控手段确定Klotho是否通过抑制PI3K/Akt的活化，进一步抑制RelA (Ser) 536磷酸化，抑制NF-κB的DNA结合及转位而发挥抗炎症作用的。为今后调节Klotho的表达，防治AKI提供理论依据。

急性肾损伤（AKI）为临床常见的严重疾病，预后差，迄今尚缺乏特异有效的治疗手段。AKI的发病机制复杂，其中炎症是介导急性肾损伤的一个重要因素。Klotho蛋白主要表达在肾小管上皮细胞，有抗衰老、抗氧化和抗凋亡作用，但是其在缺血再灌注性AKI中的具体作用机制并不明确。本项目通过对肾I/R后小鼠全身和肾脏局部Klotho表达情况、肾功能、肾小管上皮细胞的凋亡、自噬和炎症的观察，通过观察低氧/再氧化HK2细胞后细胞的凋亡、自噬炎症以及Klotho的表达情况，并结合对心脏手术后AKI和非AKI患者术前术后多个时间点的临床资料、生化检查、血Klotho水平的检测，明确缺血再灌注AKI是一种Klotho降低及炎症增强的病理状态，通过外源性补充Klotho蛋白，确定Klotho蛋白对I/R引起的肾损害的保护作用及其抗炎症作用。通过对信号通路关键蛋白的调节，观察Klotho水平改变与NF-κB信号通路的活化之间的关系，进一步阐明Klotho抑制NF-κB的信号通路。这些结果为将来进一步将Klotho作为AKI干预治疗的靶目标、防治AKI的发生发展，改善预后提供了理论依据。