Role of Pannexins in Urinary Bladder Pathology

 描述(由申请人提供)：我们最近确定，通过Pannexin通道的拉伸和化学刺激，可以从膀胱上皮(尿路上皮)释放ATP。由于嘌呤能信号被认为在膀胱病理发展中起关键作用，PAnnexin通道可能成为治疗间质性膀胱炎/痛性膀胱综合征(IC/PBS)等膀胱疾病的重要靶点。因此，我们提出的研究旨在进一步研究PAnnexin通道在尿路上皮中嘌呤能信号转导中的作用。在我们的第一个目标中，我们建议检查负责激活或失活pannin通道本身的途径，如亚硝化或磷酸化。虽然以前的研究已经阐明了导致ATP释放的各种刺激因素，但到目前为止还没有研究探讨尿路上皮细胞刺激与PAnnexin通道开放之间的联系。因此，我们将尝试确定参与激活/去激活尿路上皮细胞中的pAnnexin通道的通路。由于我们之前已经证明了用A3或A7烟碱受体激动剂模拟尿路上皮细胞可以分别激活或抑制ATP的释放，因此我们将使用这些化合物作为我们的实验刺激。我们希望这些实验 将极大地增加我们对尿路上皮刺激和ATP释放之间的联系的了解。由于ATP与多种病理性膀胱疾病密切相关，例如膀胱过度活动，我们相信这项研究有可能阐明治疗膀胱病理的新靶点。由于已发现PAnnexin通道在多种组织中对炎症小体的激活起重要作用，而炎症是膀胱病理学的重要组成部分，我们拟议的研究的后半部分将研究PAnnexin通道如何在诱导或维持膀胱炎症中发挥重要作用。为了研究这个问题，我们建议通过注射细菌脂多糖或环磷酰胺来诱导膀胱炎，并研究将PAnnexin介导的ATP释放与膀胱病理中观察到的尿频增加联系起来的信号通路。这些信号通路包括尿路上皮细胞表面嘌呤能受体的激活，NLRP3/NLRC4炎性小体的寡聚化，以及IL-1ç受体刺激下游事件的激活，如细胞旁通透性增加。我们希望，这一目标的实验将阐明 药物或基因治疗涉及炎症的病理性膀胱疾病的新靶点，如间质性膀胱炎。

 DESCRIPTION (provided by applicant): We have recently determined that ATP can be released from the urinary bladder epithelium (urothelium) in response to stretch and chemical stimulation through pannexin channels. As purinergic signaling is thought to play a critical role i the development of bladder pathology, pannexin channels may be an important target in the treatment of disorders of the urinary bladder such as interstitial cystitis/painful bladder syndrom (IC/PBS). Therefore our proposed research aims to further examine the role of pannexin channels in purinergic signaling in the urothelium. In our first aim, we propose to examine the pathways responsible for the activation or inactivation of the pannexin channel itself, such as nitrosylation or phosphorylation. While previous studies have elucidated a wide variety of stimuli responsible for causing ATP release, no studies to date have examined the pathways that connect urothelial cell stimulation to pannexin channel opening. Therefore we will attempt to determine the pathways involved in activating/deactivating pannexin channels in the urothelium. As we have previously demonstrated that simulation of urothelial cells with a3 or a7 nicotinic receptor agonists can activate or inhibit ATP release respectively, we will use these compounds in cultured rat urothelial cells as our experimental stimuli. It is our hope that these experiments will greatly increase our understanding of the mechanisms linking urothelial stimulation to ATP release. As ATP has been strongly implicated in a number of pathological bladder disorders, such as overactive bladder, we believe that this research has the potential to elucidate new targets for the treatment of bladder pathology. Because pannexin channels have been found to be important for the activation of the inflammasome in a wide variety of tissues, and inflammation is an important part of bladder pathology, the second half of our proposed study will examine how pannexin channels are important to the induction or maintenance of inflammation in the urinary bladder. To examine this question, we propose to induce bladder inflammation by injection of either bacterial lipopolysaccharides or cyclophosphamide and study the signaling pathways that connect pannexin-mediated ATP release to the increased frequency of urination observed in bladder pathology. These signaling pathways include activation of purinergic receptors on the surface of urothelial cells, the oligomerization of NLRP3/NLRC4 inflammasomes, and the activation of events downstream of IL-1ß receptor stimulation, such as increased paracellular permeability. It is our hope that the experiments in this aim will elucidate a new target for pharmacological or genetic treatment of pathological bladder disorders involving inflammation, such as interstitial cystitis.