PLA2 activation by mast cell tryptase in IC

描述（由申请人提供）：间质性膀胱炎（IC）是一种病因不明的炎性膀胱疾病，尽管尿路上皮的膀胱细胞保护缺陷和肥大细胞的病理生理作用已被涉及。我们假设这两个过程参与了炎症的恶性循环，激活的肥大细胞释放的胰蛋白酶激活尿路上皮和膀胱内皮细胞上的蛋白酶活化受体-2 (PAR-2)，导致磷脂酶A2 （PLA2）活性增加，炎症磷脂代谢产物如类二十烷和血小板活化因子（PAF）的产生加速。此外，肥大细胞胰蛋白酶可能直接或间接地通过增加尿路上皮的渗透性导致尿内容物向膀胱壁的运动增加，以及通过增加内皮细胞的渗透性和多形核白细胞（PMN）与内皮的粘附，导致膀胱壁PMN含量增加，从而加剧炎症。验证这一假设的具体目的是：1。确定胰蛋白酶刺激人尿路上皮（HUR）细胞是否通过增加PLA2活性和炎症介质（如类二十烷酸和PAF）的产生来促进炎症过程的传播。在胰酶存在和不存在的情况下，还将测量尿路上皮细胞通透性和阻力的变化以及尿路上皮伤口愈合的速度，以确定胰酶对尿路上皮屏障功能的影响。2. 通过测量PLA2活性和磷脂源性炎症介质对胰蛋白酶的反应，确定胰蛋白酶对人膀胱微血管内皮细胞的刺激是否有助于炎症过程的传播。内皮细胞的通透性、细胞表面粘附分子的表达增加以及PMN对内皮细胞单层的粘附增加将决定胰蛋白酶是否有助于PMN向膀胱募集。这些研究将提供肥大细胞在IC等情况下膀胱炎症传播中的作用的理解，并强调可能的药物干预途径，以减轻这种疾病的衰弱症状。

DESCRIPTION (provided by applicant): Interstitial cystitis (IC) is an inflammatory bladder condition with unknown etiology, although a defect in bladder cytoprotection by the urothelium and a pathophysiologic role for the mast cell has been implicated. We hypothesize that these two processes participate in a vicious cycle of inflammation, with tryptase released from activated mast cells activating the protease-activated receptor-2 (PAR-2) on urothelial and endothelial cells in the bladder and resulting in increased phospholipase A2 (PLA2) activity and accelerated production of inflammatory phospholipid metabolites such as eicosanoids and platelet activating factor (PAF). Additionally, mast cell tryptase may contribute to exacerbation of inflammation directly or indirectly by increasing the permeability of the urothelium leading to increased movement of urinary contents into the bladder wall and by increasing endothelial cell permeability and adhesion of polymorphonuclear leukocytes (PMNs) to the endothelium, resulting in increased PMN content in the bladder wall. The specific aims to test this hypothesis are: 1. To determine whether tryptase stimulation of human urothelial (HUR) cells contributes to the propagation of the inflammatory process by increasing PLA2 activity and production of inflammatory mediators, such as eicosanoids and PAF. Changes in urothelial cell permeability and resistance and the rate of wound healing in the urothelium will also be measured in the presence and absence of tryptase to determine the effect of tryptase on the barrier function of the urothelium. 2. To determine whether tryptase stimulation of human bladder microvascular endothelial cells contributes to the propagation of the inflammatory process by measuring PLA2 activity and phospholipid-derived inflammatory mediators in response to tryptase. Endothelial cell permeability, increased expression of cell surface adhesion molecules and increased PMN adherence to the endothelial cell monolayer will determine if tryptase contributes to PMN recruitment to the bladder. These studies will provide an understanding of the role of mast cells in the propagation of inflammation in the bladder in such conditions as IC and highlight possible avenues for pharmacological intervention to alleviate the debilitating symptoms of this disease.