Role of HIPK2 in Kidney Tubulointerstitial Injury

描述（由申请人提供）：HIV相关肾病（HIVAN）是非洲裔美国人终末期肾病的主要原因。尽管对疾病机制的了解越来越多，但治疗选择仍然有限。虽然基因表达微阵列已广泛应用于肾脏疾病的研究，但数据分析工具相当有限。在这里，我们提出了一种新的方法来连接的微阵列数据的上游信号激酶激活使用计算/系统生物学方法。为了实现这一点，我们已经开发了几个计算程序，包括Gene 2 Network，一个使用蛋白质-蛋白质相互作用和细胞信号传导网络来构建基于基因种子列表的子网络的系统，以及激酶富集分析（KEA），一个将蛋白质列表与最有可能调节其活性的激酶联系起来的工具。使用这种方法来研究肾脏疾病的HIV-1转基因小鼠模型（Tg 26小鼠），这是一个很好的表征人类HIVAN的动物模型，我们确定同源结构域相互作用蛋白激酶2（HIPK 2）是一种新的上游激酶调节转录因子和基因激活的Tg 26小鼠的肾脏。已知HIPK 2参与p53、TGF-2、Wnt/2-连环蛋白和Notch途径的调节，已知这些途径介导包括HIVAN在内的肾脏疾病中的细胞凋亡和纤维化。我们的初步数据表明，HIPK 2蛋白表达显着增加，在肾小管间质室的Tg 26小鼠和人类与HIVAN。此外，HIPK 2介导HIV诱导的肾小管上皮细胞的凋亡和上皮-间质转化（EMT），导致肾纤维化。基于这些初步数据，我们假设HIPK 2是一种上游蛋白激酶，介导了HIV和其他肾脏疾病中的肾小管间质损伤。为了验证我们的假设，我们提出了以下具体目标：具体目标1：通过确认HIPK 2在HIV感染细胞的凋亡和EMT中的作用，并通过确定HIV激活的HIPK 2上游和下游的信号通路，检查HIPK 2在体外的作用。具体目标2：通过研究HIPK 2敲除小鼠在单侧输尿管梗阻模型中是否免受肾小管间质损伤的发展，并通过评估HIPK 2敲除对Tg 26中肾小管间质损伤发展的影响，确认HIPK 2在体内的作用。 公共卫生相关性：HIPK 2可能是一种新的上游激酶，激活多个下游途径，导致肾小管间质损伤，这是慢性肾脏疾病进展的最终共同途径。HIPK 2可能成为治疗HIV相关肾病以及其他肾脏疾病的潜在新靶点。我们的研究还将提供一种新的方法，将上游信号通路与基因表达微阵列的数据联系起来，这可以帮助我们确定HIVAN以及其他疾病中导致肾损伤的关键上游激酶。

DESCRIPTION (provided by applicant): HIV-associated nephropathy (HIVAN) is a leading cause of end stage kidney disease among African-Americans. Despite growing knowledge of the disease mechanism, therapeutic options have been limited. While gene expression microarray has been widely applied for the study of kidney diseases, data analytical tools are quite limited. Here we propose a novel approach to link the microarray data to the upstream signaling kinase activation using computation/systems biology approach. To accomplish this, we have developed several computational programs including Gene2 Network, a system that uses protein-protein interactions and cell signaling networks to build subnetworks based on seed lists of genes, and kinase enrichment analysis (KEA), a tool that links lists of proteins to the kinases most likely regulating their activity. Using this approach to study the kidney disease in a HIV-1 transgenic mouse model (Tg26 mice), which is a well-characterized animal model for human HIVAN, we identified that homeodomain interacting protein kinase 2 (HIPK2) is a novel upstream kinase regulating the transcription factors and genes activated in kidneys of Tg26 mice. HIPK2 is known to be involved in the regulation of p53, TGF-2, Wnt/2-catenin, and Notch pathways, which are known to mediate apoptosis and fibrosis in kidney disease including HIVAN. Our preliminary data suggest that HIPK2 protein expression is increased markedly in the renal tubulo-interstitial compartment of Tg26 mice and human with HIVAN. In addition, HIPK2 mediates HIV-induced apoptosis and epithelial-mesenchymal transition (EMT) of renal tubular epithelia cells, contributing to kidney fibrosis. Based on these preliminary data we hypothesize that HIPK2 is an upstream protein kinase that mediates tubulointersitial injury in HIVAN and in other kidney diseases. To test our hypotheses, we propose the following specific aims: Specific aim 1: Examine the role of HIPK2 in vitro by confirming the role of HIPK2 in apoptosis and EMT of HIV-infected cells and by determining signaling pathways up- and down-stream of HIPK2 that are activated by HIV. Specific aim 2: Confirm the role of HIPK2 in vivo by investigating whether HIPK2 knockout mice are protected from the development of tubulointerstitial injury in the unilateral ureteral obstruction model and by assessing the effect of HIPK2 knockout on the development of tubulointerstitial injury in Tg26. PUBLIC HEALTH RELEVANCE: HIPK2 could be a novel upstream kinase activating multiple downstream pathways leading to tubulo-interstitial injury, which is a final common pathway in the progression of chronic kidney disease. HIPK2 could be a potential new therapeutic target for the treatment of HIV-associated nephropathy as well as other kidney diseases. Our studies will also provide a novel approach to link upstream signaling pathways to data from gene expression microarray, which could help us to identify key upstream kinases responsible for kidney injury in HIVAN, as well as in other diseases.