Targeting heat shock protein 72 to improve renal function after transplantation

项目摘要 对于接受已故捐赠者肾脏的人来说，长期移植功能往往很差， 占移植总数的70%。造成这些不良结果的一个关键因素是器官的冷藏（CS）， 这在保存期间引起损伤。因此，迫切需要了解 CS通过其激活诱导受体肾损伤的分子途径。我们的长期目标是 识别这些CS相关通路，并在CS期间应用靶向治疗，以改善结局， 移植相关死亡率。CS诱导的肾损伤的重要分子决定因素之一是 蛋白质稳态异常在应激过程中，热休克蛋白和蛋白酶体协同作用， 维持蛋白质稳态。Hsp 72是Hsc 70的主要应激诱导同源物， 热休克蛋白70家族，在所有有核细胞中表现出管家功能， for cell细胞survival生存.重要的是，Hsc 70和Hsp 72通过结合受损的蛋白质并募集细胞中的蛋白质来发挥关键作用。 蛋白酶体进行靶向降解，防止受损蛋白质的非特异性聚集。此外 除了其保护作用外，Hsp 72还通过调节细胞内蛋白质的表达而参与许多人类疾病的发病机制。 免疫系统和炎症。使用临床相关的肾CS大鼠模型， 我们发现，CS降低了蛋白酶体功能，并损害了蛋白质的稳态， 移植CS如何降低移植物中的蛋白酶体功能尚不清楚。我们假设CS- HSF 1和p38 MAPK介导的活化介导Hsp 72的上调和Rpt 6的磷酸化， 导致移植后蛋白酶体功能障碍和损伤。我们有初步数据支持这一点 假说.我们还建立了CS/移植的动物模型，更好地模拟了临床实际 比简单的CS/温灌注更有效，并且将允许我们通过3个特定目标来测试我们的假设。目的 1：确定肾CS期间Hsp 72上调的机制及其对蛋白酶体功能障碍的影响， 移植目的2：阐明Rpt 6磷酸化/聚集的机制及其对细胞凋亡的影响。 蛋白酶体功能障碍的肾CS和移植。目的3：确定 Hsp 72抑制剂HS-72使用肾CS和移植的大鼠和人模型。该项目使用了 临床相关的大鼠肾移植模型以及离体人肾灌注泵以测试效果 新的基于CS的疗法（例如，HS-72）对移植后蛋白酶体/肾功能的影响。我们期望 鉴定CS和移植后蛋白酶体功能障碍和肾损伤分子介质。这些 研究结果将很容易翻译，例如通过给予靶向这些途径的药物， 改善终末期肾移植患者移植结局和降低死亡率解决方案 疾病

PROJECT SUMMARY ABSTRACT Long-term allograft function tends to be poor for people who receive kidneys from deceased donors, which comprise 70% of total transplants. A key contributor to these poor outcomes is cold storage (CS) of the organs, which induces injury during preservation. Accordingly, there is an urgent need to understand the mechanisms by which CS activates molecular pathways that induce renal damage in the recipient. Our long-term goal is to identify these CS-related pathways and apply targeted therapies during CS to improve outcomes and decrease transplant-associated mortality. One of the important molecular determinants of CS-induced kidney injury is abnormal protein homeostasis. During stress, heat-shock proteins and the proteasome play a concerted role in maintaining protein homeostasis. Hsp72 is the major stress-inducible homologue of Hsc70, the cognate member of the heat-shock protein 70 family that exhibits housekeeping function in all nucleated cells and is necessary for cell survival. Importantly, Hsc70 and Hsp72 play critical roles by binding damaged proteins and recruiting the proteasome for targeted degradation, preventing the nonspecific aggregation of damaged proteins. In addition to its protective roles, Hsp72 is implicated in the pathogenesis of numerous human diseases by modulating the immune system and inflammation. Using a clinically relevant rat model of renal CS combined with transplantation, we showed that CS decreases proteasome function and impairs protein homeostasis in the transplants. How CS decreases proteasome function in the transplants is not known. We hypothesize that CS- mediated activation of HSF1 and p38MAPK mediate the upregulation of Hsp72 and phosphorylation of Rpt6, leading to proteasome dysfunction and injury after transplantation. We have preliminary data supporting this hypothesis. We have also established animal models of CS/transplantation, which mimic the clinical reality more effectively than simple CS/warm perfusion and will allow us to test our hypothesis through 3 specific aims. Aim 1: Define the mechanism of Hsp72 upregulation and its impact on proteasome dysfunction during renal CS and transplantation. Aim 2: Delineate the mechanism of Rpt6 phosphorylation/aggregation and its impact on proteasome dysfunction during renal CS and transplantation. Aim 3: Determine the therapeutic utility of the Hsp72 inhibitor HS-72 using both rat and human models of renal CS and transplantation. This project uses a clinically relevant rat kidney transplant model as well as ex vivo human kidney perfusion pump to test the effects of novel CS-based therapies (e.g., HS-72) on proteasome/renal function after transplantation. We expect to identify molecular mediators of proteasome dysfunction and renal injury following CS and transplantation. These findings would be readily translatable, such as by administering drugs targeting these pathways to the CS solution to improve transplant outcomes and reduce mortality for transplant patients with end-stage kidney disease.