Cyclin-dependent Kinase Inhibitor in Acute Renal Failure

描述(申请人提供)：我们的长期目标是预防/治疗急性肾损伤。我们正在使用顺铂毒性作为肾脏损伤的模型，在体外使用培养的小鼠肾近端小管细胞，并在体内使用野生型和转基因小鼠。我们已经证实，抑制细胞周期相关的酶，细胞周期蛋白依赖性激酶-2(CDK2)，在体外保护细胞毒性，并在体内保护顺铂引起的肾脏损伤。基于这些发现，我们培育了两个转基因小鼠品系，由于特异性CDK2抑制，它们对顺铂诱导的急性肾损伤具有抵抗力。我们发现，细胞死亡的几条途径依赖于CDK2的活性，并有助于顺铂的细胞毒性。我们假设，细胞死亡由顺铂激活，并依赖于CDK2激酶活性，可能可以通过交叉途径而不是平行途径来解释。现在我们发现，作为对顺铂的反应，CDK2磷酸化了两种蛋白，p21和BclxL，这两种蛋白可以直接或间接地影响细胞死亡途径。在我们的第一个特定目标中，我们将调查这些蛋白质是否提供了细胞周期和细胞死亡的交叉点。我们假设抑制CDK2将是预防AKI的有效的短期和长期策略。我们最近开发的转基因小鼠诱导了p21或dN-CDK2的表达，使其免受顺铂肾毒性的保护，证实了这一假设的前半部分。我们假设的后半部分将在第二个具体目标中解决，这将确定抑制CDK2是否只是推迟肾毒性，以及CDK2抑制和顺铂暴露是否会对肾脏恢复造成长期影响。

DESCRIPTION (provided by applicant): Our long-term goal is to prevent/treat acute kidney injury. We are using cisplatin toxicity as a model of renal injury, in vitro using cultured mouse kidney proximal tubule cells, and in vivo using wild-type and transgenic mice. We have established that inhibition of a cell cycle-associated enzyme, cyclin-dependent kinase-2 (Cdk2), protect from cytotoxicity in vitro and protects from kidney injury in vivo caused by cisplatin administration. Based on these findings, we developed two transgenic mouse strains resistant to cisplatin-induced acute renal injury because of specific cdk2 inhibition. We found that several pathways of cell death were dependent on Cdk2 activity and contribute to cisplatin cytotoxicity. We hypothesize that cell death activated by cisplatin and dependent on Cdk2 kinase activity can likely be explained by intersecting rather than parallel pathways. Now we find that in response to cisplatin, Cdk2 phosphorylates two proteins, p21 and Bcl xL, that directly and indirectly could have effects on cell death pathways. In our first specific aim we will investigate whether these proteins provide the intersections of cell cycle and cell death. We hypothesize that Cdk2 inhibition would be an effective short- and long-term strategy to prevent AKI. Our recently developed transgenic mice in which induced expression of either p21 or DN-Cdk2 protected from cisplatin nephrotoxicity confirmed the first half of this hypothesis. The second half of our hypothesis will be addressed in this second specific aim, which will determine whether Cdk2inhibition merely delays nephrotoxicity and whether Cdk2 inhibition and cisplatin exposure causes longer-term effects on kidney recovery.