Caspase-1 signaling in ischemic acute renal failure

描述（由申请人提供）：本授权中提出的总体假设提供了一个完整的病理生理学模式，其中半胱天冬酶-1和半胱天冬酶-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衰竭（ARF）。新发表的数据表明，受损的IL-18处理保护caspase-1缺陷小鼠缺血性ARF支持这一假设。将在不同模型中进行小鼠补充研究：1）体内缺血性ARF，2）悬浮液中新鲜分离的肾近端小管和3）培养中的微血管内皮细胞。在特定目标1中，将确定缺血性ARF中caspase-1和IL-18表达增加的时间过程。此外，新开发的caspase-1和IL-18抑制剂的治疗潜力将被测试。Fractalkine是巨噬细胞和NK细胞的主要化学引诱物。在特定目标2中，我们将确定内皮中是否存在精氨酸介导的fractalkine增加。具体目标3关注巨噬细胞和NK细胞作为缺血性ARF中半胱天冬酶-1、IL-18、IL-1a和其他细胞因子的来源。使用巨噬细胞和NK细胞抑制剂的体内研究将测试临床应用的潜力。已知由IL-18刺激的活化的巨噬细胞和NK细胞通过穿孔素和/或颗粒酶介导细胞裂解。在具体目标4中，我们提出巨噬细胞和NK细胞依赖或不依赖IL-18的穿孔素和gzmA的产生有助于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。这些结果将为缺血性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。这是特别真实的，因为目前可用的半胱天冬酶-1和IL-18抑制剂，例如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.