New Therapeutic Leads for Proteinuric Kidney Diseases

修改后的项目摘要/摘要 该项目的主要目标是在临床前动物模型和蛋白尿性肾病的人类肾脏活检样本中验证针对ROBO/SIIT信号通路的新的治疗先导。ROBO(包括Robo1/2)是缝隙配体(包括SLIT2/3)的受体。ROBO/SIIT途径已被证明在肾脏早期发育过程中发挥重要作用。Robo1、ROBO2或Slit2的突变会导致人类和小鼠的先天性肾脏和尿路异常(CAKUT)和膀胱输尿管反流(VUR)。我们还在成熟的肾脏足细胞中发现了一种新的、意想不到的功能，该信号通路可以通过抑制非肌球肌球蛋白IIA(NM-IIA)的活性来抑制neparin诱导的肌动蛋白聚合，并破坏足细胞与肾小球基底膜(GBM)的黏附和黏附。此外，我们发现，在足细胞损伤和足细胞病变动物模型中，从基因上抑制ROBO/Sit途径可以通过增强足细胞黏附来减少蛋白尿，从而维持足细胞足突、裂隙-横隔膜超微结构和足细胞支撑力。这些数据表明，ROBO/SIT通路是一种新的足细胞损伤和保护的药物靶点。阻断ROBO/SIIT通路可能会为足细胞损伤和蛋白尿患者带来潜在的新疗法。事实上，在与辉瑞的合作中，我们产生了几种抑制ROBO/Sit途径的新的治疗线索。其中一个新的治疗线索，PF-06730512，显著减少了临床前蛋白尿动物模型的蛋白尿。这种PF-06730512目前正处于FSGS患者的第二阶段临床试验中。这项第二阶段试验的最新中期分析显示，在接受PF-06730512治疗12周后，类固醇/治疗耐药的FSGS患者的蛋白尿显著减少。在这个特别的NIDDK早期临床前治疗线索验证项目中，我们计划测试我们与辉瑞合作开发的另一种抑制Robo1和ROBO2受体的新型治疗铅在蛋白尿肾病和CAKUT临床前动物模型中的有效性和安全性(目标1和目标2)。此外，我们计划验证ROBO/Sit通路基因/蛋白在肾活检样本中的表达，这些样本来自蛋白尿肾病患者(目标3)。该项目将支持具有不同作用机制的ROBO/SIT抑制剂的适应症扩大，以进一步增加针对ROBO/SIT途径治疗蛋白尿肾病的药物开发项目成功的总体可能性。

Modified Project Summary/Abstract The primary goal of this project is to validate a novel therapeutic lead targeting the ROBO/SLIT signaling pathway in pre-clinical animal models and human kidney biopsy samples of proteinuric kidney disease. ROBO (including ROBO1/2) are receptors for SLIT ligands (including SLIT2/3). ROBO/SLIT pathway has been shown to play an essential role during early kidney development. Mutations in either ROBO1, ROBO2, or SLIT2 cause congenital anomalies of the kidney and urinary tract (CAKUT) and vesicoureteral reflux (VUR) in humans and mice. We also discovered a novel, unexpected function of the ROBO/SLIT pathway in mature kidney podocytes, which acts as a negative regulator on nephrin to inhibit nephrin-induced actin polymerization and destabilizes podocyte adhesion and attachment to the glomerular basement membrane (GBM) by inhibiting nonmuscle myosin IIA (NM-IIA) activity. In addition, we found that inhibiting the ROBO/SLIT pathway genetically in animal models of podocyte injury and podocytopathies reduced albuminuria by enhanced podocyte adhesion, which maintained the podocyte foot process, slit-diaphragm ultrastructure, and the podocyte buttress force. These data suggest that the ROBO/SLIT pathway is a novel drug target for podocyte injury and podocyte protection. Blocking the ROBO/SLIT pathway may lead to potentially novel therapies for patients with podocyte injury and albuminuria. Indeed, in collaboration with Pfizer, we generated several novel therapeutic leads inhibiting the ROBO/SLIT pathway. One of the novel therapeutic leads, PF-06730512, significantly reduced albuminuria in pre-clinical proteinuric animal models. This PF-06730512 is currently in a phase 2 clinical trial for patients with FSGS. The latest interim analysis of this phase 2 trial showed a significant proteinuria reduction in steroid/treatment-resistant FSGS patients after 12 weeks of PF-06730512 treatment. In this special NIDDK early-stage preclinical therapeutic leads validation project, we plan to test the efficacy and safety of one additional novel therapeutic lead inhibiting ROBO1 and ROBO2 receptors that we generated in collaboration with Pfizer in pre-clinical animal models of proteinuric kidney disease and CAKUT (Aim 1 and Aim 2). In addition, we plan to validate ROBO/SLIT pathway gene/protein expressions in kidney biopsy samples that have been collected from patients with proteinuric kidney disease (Aim 3). This project will support the indication expansion of the ROBO/SLIT inhibitors with different mechanisms of action to further increase the overall likelihood of a successful drug development project targeting the ROBO/SLIT pathway for proteinuric kidney disease.