Identification of new therapeutic targets for ADPKD

常染色体显性多囊肾病（ADPKD）影响全球超过1200万人， 终末期肾病（ESKD）的常见原因。ADPKD是由两个基因之一的突变引起的， PKD 1或PKD 2，分别编码多囊蛋白1（PC）和PC 2。PC 1或PC 2丢失导致 许多激酶和下游信号通路的激活，这是发病机制的核心。 ADPKD囊肿生长。此外，抑制一些不同的激酶上调， 在PKD动物模型中，PKD肾脏已显示出减缓囊肿生长， 最有希望的一类候选药物治疗ADPKD患者。然而，尽管人类激酶组 由超过500种激酶组成，只有一小部分这些激酶已经过测试，以确定它们是否发挥作用。 在ADPKD发病机制中的作用。因此，可能有许多激酶在ADPKD肾脏中活跃， 在囊肿生长中起着重要作用，这些作用尚未被发现，可能是良好的治疗靶点。 与坦普尔大学的詹姆斯邓肯合作，我们现在已经采用了一种新的方法， 以无偏的方式广泛筛选PKD肾脏中在来自 PKD肾与来自野生型肾的裂解物的比较。在该测定中，活性激酶是亲和的。 通过使裂解物通过含有激酶抑制剂混合物的多重抑制剂珠（MIB）来捕获。 然后通过LC分离，随后通过定量串联质谱法（LC-MS）鉴定结合的激酶。 MS/MS）。使用这种方法，我们现在已经确定了一些已知和未知的激酶 尤其是在PKD肾脏中上调和下调。 这项建议的主要目标是评估迄今为止确定的几种激酶的作用，这些激酶的活性 在PKD肾脏中增加，并确定是否抑制或激活任何鉴定的激酶， 囊肿生长，抑制间质纤维化，并保护ADPKD动物模型的肾功能。然后我们将 采取有偏见和无偏见的方法来确定由这些激酶调节的信号通路， 对于发病机制至关重要，目标是更完整地了解相关信号中心 以及PKD肾脏中异常激活的网络。此外，我们将利用这项技术广泛地 在不同阶段从各种不同的ADPKD“早期”和“晚期”小鼠模型中筛选PKD肾脏， 囊肿形成和ADPKD人类患者肾脏中，以公正的方式确定其他 在PKD肾脏中激活和抑制的激酶，以确定 小鼠模型，哪些激酶可能与人类疾病最相关，以及不同的激酶组是否 在囊肿诱导后早期被激活，并作为囊肿生长的早期“驱动器”发挥作用。最终，我们希望 新的信息将确定新的安全药物靶点和合理的联合治疗方法，以减缓 囊肿生长，然后可以转化为临床试验。

Autosomal-dominant polycystic kidney disease (ADPKD) affects more than 12 million people worldwide and is a common cause of end-stage kidney disease (ESKD). ADPKD is caused by mutations in one of two genes, PKD1 or PKD2, which encodes polycystin 1 (PC) and PC2 respectively. Loss of PC1 or PC2 results in activation of numerous kinases and downstream signaling pathways, which is central to the pathogenesis of cyst growth in ADPKD. In addition, pharmacologically inhibiting a number of different kinases up-regulated in PKD kidneys has been shown to slow cyst growth in animal models of PKD making kinase inhibitors among the most promising class of drug candidates to treat patients with ADPKD. However, while the human kinome consists of more than 500 kinases, only a fraction of these kinases have been tested to determine if they play a role in ADPKD pathogenesis. As a result, there are likely many kinases that are active in ADPKD kidneys that play prominent roles in cyst growth that are yet-to-be discovered and may be good therapeutic targets. In collaboration with James Duncan at Temple University, we have now adapted a novel approach to broadly screen PKD kidneys in an unbiased manner for kinases that are more active in lysates from PKD kidneys compared with lysates from wild type kidneys. In this assay, active kinases are affinity captured by passing lysates over multiplex inhibitor beads (MIB) containing a cocktail of kinase inhibitors. Bound kinases are then identified by LC separation followed by quantitative tandem mass spectrometry (LC- MS/MS). Using this approach, we have now identified a number of both known and unknown kinases specifically up-regulated and down-regulated in PKD kidneys. The major goal of this proposal is to assess the role of several of the kinases identified thus far whose activity is increased in PKD kidneys and determine whether inhibiting or activating any of the kinases identified slows cyst growth, inhibits interstitial fibrosis, and preserves renal function in animal models of ADPKD. We will then take both biased and unbiased approaches to identify the signaling pathways regulated by these kinases that are critical to pathogenesis with the goal of developing a more complete picture of the relevant signaling hubs and networks that are aberrantly activated in PKD kidneys. In addition, we will use this technology to broadly screen PKD kidneys from a variety of different “early” and “late” mouse models of ADPKD at different stages in cyst formation and in kidneys from human patients with ADPKD to identify in an unbiased manner additional kinases that are activated and inhibited in PKD kidneys to determine the similarities and differences between mouse models, which kinases may be most relevant to human disease, and whether distinct sets of kinases are activated early post cyst induction and function as early “drivers” of cyst growth. Ultimately, we hope this new information will identify new safe drug targets and rational approaches to combination therapies to slow cyst growth that can then be translated into clinical trials.