Cyclin-dependent Kinase Inhibitor In Acute Renal Failure

描述（由申请人提供）：我们的长期目标是预防和/或治疗急性肾衰竭。我们发现，p21细胞周期蛋白依赖性激酶（cdk）抑制剂基因的激活改善了顺铂给药和肾缺血/再灌注后的肾功能衰竭。在这些损伤之后，比较p21（+/+）和p21（-/-）小鼠，在p21（+/+）群体中，细胞损伤显著更少，包括坏死和凋亡，功能性肾衰竭更少，死亡率更低。该机制直接依赖于p21作为细胞周期调节因子的作用。我们现在发现，在顺铂暴露之前使用腺病毒载体诱导p21完全保护体外小鼠肾近曲小管细胞免受细胞毒性。同样，用不同的药理学cdk 2抑制剂或已知诱导p21的组蛋白脱乙酰酶（HDAC）抑制剂预处理肾细胞也具有保护作用。我们扩展了这些发现，显示cdk 2抑制药物，具有类似于p21的活性谱，也保护肾功能和细胞形态在体内顺铂诱导的肾损伤。我们假设cdk 2抑制剂通过抑制顺铂暴露激活的细胞死亡途径来保护肾细胞免受顺铂诱导的毒性。此外，我们推测cdk 2抑制剂将有助于预防和治疗急性肾功能衰竭。我们的目标是确定cdk抑制剂在体外和体内的保护机制，并提供利用cdk抑制剂改善顺铂诱导的肾功能衰竭的初步步骤。我们的第一个具体目标是确定cdk抑制剂的保护机制。我们将证实cdk抑制剂的保护作用依赖于抑制cdk 2的活性。我们将确定cdk 2的定位和cdk 2-p21相互作用的定位。我们将确定cdk 2抑制剂抑制的细胞死亡途径，并确定每种cdk 2抑制剂抑制的死亡途径是否被顺铂激活。我们的第二个具体目标是确定cdk 2抑制剂在体内保护的条件和机制。我们将确定cdk 2基因敲除小鼠是否能免受顺铂肾毒性的影响，以及p21基因的相同片段在体外是否也能在体内起到保护作用。我们将确认purvalanol在体内的保护作用，并完善其作用的条件。

DESCRIPTION (provided by applicant): Our long-term objective is to prevent and/or treat acute renal failure. We showed that activation of the gene for the p21 cyclin-dependent kinase (cdk) inhibitor ameliorated renal failure after cisplatin administration and renal ischemia/reperfusion. After these injuries, comparing p21(+/+) with p21(-/-) mice, there was significantly less cellular damage, including both necrosis and apoptosis, less functional kidney failure, and less mortality in the p21(+/+) population. The mechanism was directly dependent on the role of p21 as a regulator of the cell cycle. We now find that induction of p21 using an adenoviral vector before cisplatin exposure completely protected mouse kidney proximal tubule cells in vitro from cytotoxicity. Similarly, pretreatment of kidney cells with different pharmacologic cdk2 inhibitors or with a histone deacetylase (HDAC) inhibitor known to induce p21 was also protective. We extended these findings by showing that a cdk2 inhibitory drug, with a spectrum of activity similar to p21, also protected kidney function and cell morphology in vivo from cisplatin-induced renal injury. We hypothesize that cdk2 inhibitors protect kidney cells from cisplatin-induced toxicity by inhibiting cell death pathways activated by cisplatin exposure. Furthermore, we hypothesize that cdk2 inhibitors will be useful to prevent and treat acute renal failure. We have developed aims that will determine the mechanism of cdk inhibitor protection in vitro and in vivo and provide initial steps to utilize cdk inhibitors to ameliorate cisplatin-induced renal failure. Our first specific aim is to determine the mechanism of cdk inhibitor protection. We will confirm that cdk inhibitor protection is dependent on repressing cdk2 activity. We will determine cdk2 localization and the localization of cdk2-p21 interaction. We will determine the cell death pathway(s) inhibited by cdk2 inhibitors, and for each death pathway inhibited by cdk2 inhibitors, determine whether it is activated by cisplatin. Our second specific aim is to determine conditions and mechanisms of protection by cdk2 inhibitors in vivo. We will determine whether cdk2 knock-out mice are protected from cisplatin nephrotoxicity, and whether the same fragment of p21 that protects in vitro also protects in vivo. We will confirm purvalanol in vivo protection and refine the conditions for its action.