Caspase-1 signaling in ischemic acute renal failure

描述（由申请人提供）：本拨款提出的总体假设提供了一个完整的病理生理模式，其中caspase-1和caspase-1相关细胞因子如IL-18和IL-1a导致肾脏中巨噬细胞和NK细胞浸润增加并导致缺血性急性肾功能衰竭（ARF）。新发表的数据表明，受损的IL-18加工可以保护caspase-1缺陷小鼠免于缺血性ARF，这支持了这一假设。对小鼠的补充研究将在不同的模型中进行：1)体内缺血性ARF， 2)新鲜分离的肾近端小管悬浮和3)微血管内皮细胞培养。在Specific Aim 1中，我们将确定caspase-1和IL-18在缺血性ARF中表达升高的时间过程。此外，还将测试新开发的caspase-1和IL-18抑制剂的治疗潜力。Fractalkine是巨噬细胞和NK细胞的主要化学引诱剂。在特异性目标2中，我们将确定内皮中是否存在细胞因子介导的fractalkine升高。特异性Aim 3关注巨噬细胞和NK细胞在缺血性ARF中作为caspase-1、IL-18、IL-1a等细胞因子的来源。使用巨噬细胞和NK细胞抑制剂的体内研究将测试其临床应用的潜力。活化的巨噬细胞和受IL-18刺激的NK细胞通过穿孔蛋白和/或颗粒酶介导细胞裂解。在Specific Aim 4中，我们提出巨噬细胞和NK细胞依赖il -18或独立产生穿孔素和gzmA有助于FT损伤（体外）和ATN（体内）。这些研究与临床ARF的相关性是实质性的。该结果将为缺血性ARF的病理生理学提供新的见解，并有助于改变缺血性ARF的病程。这一点尤其正确，因为目前有caspase-1和IL-18抑制剂，如pralnacasan和IL-18结合蛋白（IL-18 BP）正在临床试验中进行测试。

DESCRIPTION (provided by applicant): The overall hypothesis presented in this grant provides an integrated pathophysiological schema whereby caspase-1 and caspase-1-related cytokines like IL-18 and IL-1a lead to increased macrophage and NK cell infiltration in the kidney and resultant ischemic acute renal failure (ARF). Novel published data demonstrating that impaired IL-18 processing protects caspase-1 deficient mice from ischemic ARF supports the hypothesis. Complementary studies in mice will be performed in different models: 1) ischemic ARF in vivo, 2) freshly isolated renal proximal tubules in suspension and 3) microvascular endothelial cells in culture. In Specific Aim 1, the time course of increased caspase-1 and IL-18 expression in ischemic ARF will be determined. In addition, the therapeutic potential of newly developed caspase-1 and IL-18 inhibitors will be tested. Fractalkine is a major chemoattractant for macrophages and NK cells. In Specific Aim 2, we shall determine whether there is a cytokine-mediated increase of fractalkine in the endothelium. Specific Aim 3 focuses on macrophages and NK cells as sources of caspase-1, IL-18, IL-1a and other cytokines in ischemic ARF. In vivo studies using inhibitors of macrophages and NK cells will test the potential for clinical application. Activated macrophages and NK cells stimulated by IL-18 are known to mediate cell lysis via perforin and/or granzymes. In Specific Aim 4, we propose that IL-18-dependent or independent production of perforin and gzmA by macrophages and NK cells contributes to FT injury (in vitro) and ATN (in vivo). The relevance of these studies to clinical ARF is substantial. The results should provide new insights into the pathophysiology of ischemic ARF as well as leads to altering the course of ischemic ARF. This is particularly true because of the current availability of caspase-1 and IL-18 inhibitors e.g. pralnacasan and IL-18 binding protein (IL-18 BP) that are being tested in clinical trials.