Human Bladder Urothelial Cell Structure and Function in Bladder Hypersensation

描述(申请人提供)：膀胱尿路上皮细胞(BUG)与人类疾病的相关性传统上仅从尿路上皮细胞癌的角度来理解。然而，有令人兴奋的新文献强调了改变的细菌结构和功能在非肿瘤状态中的作用。间质性膀胱炎(IC)和膀胱过度活动症(OAB)这两种非常普遍但知之甚少的疾病可能都与膀胱尿路上皮的病理性变化有关。这两种情况都以感觉过敏症状为特征，如尿急、尿频和膀胱疼痛。 我们建议研究膀胱尿路上皮的结构和功能，因为它与IC和OAB的正常和感觉过敏条件有关。最近对膀胱尿路上皮管腔一侧的扫描电子显微镜显示，IC和对照的顶伞细胞(AUC)之间有明显的变化。这些变化可能是由于尿路蛋白表达异常所致。Uroplakins是仅在尿路上皮细胞中由AUC表达的独特蛋白质，在AUC膜结构和功能中发挥作用。体外培养的人ICBUC也存在异常，包括嘌呤能信号增强，某些生长因子(HB-EGF、EGF和APF)的表达改变，以及钾电导降低(由离子通道Kir2.1和BK介导)，导致去极化。膀胱尿路上皮M_2受体的发现为使用抗M_2受体治疗OAB提供了另一种作用机制。 这项资助将检验以下4个假设：1.膀胱感觉过敏患者的AUC存在与尿路蛋白相关的结构异常。2.膀胱感觉过敏患者的膀胱尿路上皮改变了紧密连接蛋白(ZO-1、occludin)、Kir2.1、BK、M2、HB-EGF、EGF和APF的蛋白表达。3.离子通道Kir2.1的电导在IC BUC中降低。这种情况可以用HB-EGF治疗逆转。APF治疗可使正常BUC的Kir2.1电导降低。4.人BUC的BK通道电导受M2受体的调节。OAB和IC BUC细胞外向钾电流降低，hSIo基因可逆转此现象。通过实现这些目标，我们希望对感觉过敏膀胱疾病的发病机制有一个了解，这最终可以导致有针对性的治疗选择。

DESCRIPTION (provided by applicant): The relevance of bladder urothelial cells (BUG) to human disease has traditionally been understood only in terms of urothelial cell carcinoma. However, there is exciting new literature highlighting the role of altered BUG structure and function in non-neoplastic states. Two highly prevalent yet poorly understood conditions, interstitial cystitis (IC) and overactive bladder (OAB) may both be associated with pathogenic changes in the bladder urothelium. Both of these conditions are characterized by hypersensory symptoms such as urinary urgency, frequency, and bladder pain. We propose to study the structure and function of the bladder urothelium as it relates to both normal and hypersensory conditions of IC and OAB. Recent scanning electron microscopy of the lumenal side of the bladder urothelium show distinct changes between IC and control apical umbrella cells (AUC). These changes could be due to abnormalities in uroplakins expression. Uroplakins are unique proteins expressed only by the AUC in the urothelium and play a role in AUC membrane structure and function. Human IC BUC grown in culture also had abnormalities including augmented purinergic signaling, altered expression of certain growth factors (HB-EGF, EGF and APF), and decreased potassium conductance (mediated by ion channels Kir2.1 and BK) leading to depolarization. The discovery of muscarinic M2 receptors on the bladder urothelium provides another mechanism of action in the use of antimuscarinics in treatment of OAB. This grant will test the following 4 hypotheses: 1. AUC from patients with bladder hypersensory conditions have structural abnormalities related to uroplakins. 2. The bladder urothelium from patients with bladder hypersensory conditions have altered protein expressions of tight junction proteins (ZO-1, occludin), Kir2.1, BK, M2, HB-EGF, EGF and APF. 3. The conductance of ion channel Kir2.1 is decreased in IC BUC. This can be reversed with HB-EGF treatment. Normal BUC can be made to have decreased Kir2.1 conductance with APF treatment. 4. The conductance of the BK channel is regulated by M2 receptors in human BUC. There is a decreased outward potassium current in OAB and IC BUC which can be reversed by hSIo cDNA transfection. By accomplishing these aims, we hope to develop an understanding of the pathogenesis of hypersensory bladder conditions which ultimately can lead to targeted treatment options.