The Role of Selectin-Mediated Recognition in Glaucoma

描述（由申请人提供）：青光眼是世界上仅次于白内障的第二大致盲原因，影响着大约7000万人。水流出通道阻塞引起的眼压升高是原发性开角型青光眼发生的主要危险因素。由于缺乏对流出设施抵抗的分子机制的理解，这种致盲疾病的治疗受到损害。在最近的一项研究中，碳水化合物结合蛋白e-选择素（ELAM-1, CD62E）被确定为青光眼的特异性分子标志物。结果表明，虽然e -选择素在不同病因的青光眼流出通道的小梁网（TM）细胞中一致存在，但在所有正常眼睛的流出通道中均不存在。我们提出了一个独特的假设，即TM细胞表面e -选择素通过与邻近细胞或房水中假定的糖蛋白反受体结合，激活关键的信号通路，进而通过促进细胞-基质和/或细胞-细胞相互作用和细胞骨架变化，提供眼睛水流出通道特有的保护性应激反应。在本NEI R03申请中，我们建议进行试点研究，以确定该假设是否值得进行详细调查。在目的1中，使用免疫组织化学和Western blot分析，我们将确定选择素的特定碳水化合物配体，如果有的话，在正常和青光眼的TM细胞和房液中表达。在Aim 2中，我们将在体外确定选择素/碳水化合物介导的信号传导是否促进TM细胞对多种细胞外基质分子的粘附。我们的研究将确定以选择蛋白为基础的碳水化合物识别系统是否在青光眼水流出阻力的发病机制中起作用。

DESCRIPTION (provided by applicant): Glaucoma is the second leading cause of blindness in the world after cataract, affecting approximately 70 million people. Elevated intraocular pressure due to the obstruction of the aqueous outflow pathway is a major causal risk factor in the development of primary open-angle glaucoma. Treatment of this blinding disease is compromised because of the lack of understanding of the molecular mechanism responsible for the resistance to the outflow facility. In a recent study, a carbohydrate-binding protein, E-selectin (ELAM-1, CD62E), was identified as a specific molecular marker of glaucoma. It was demonstrated that while E-selectin is consistently present on trabecular meshwork (TM) cells in the outflow pathways of eyes of glaucomas of diverse etiology, it was absent in the outflow pathway of all normal eyes examined. We propose a unique hypothesis that TM cell surface E-selectin, by binding to its putative glycoprotein counterreceptors on adjacent cells or in aqueous humor activates key signaling pathways, which in turn, by promoting cell-matrix and/or cell-to-cell interactions and cytoskeletal changes, provide a protective stress response specific to the aqueous outflow pathway of the eye. In this NEI R03 application, we propose pilot studies to determine whether the hypothesis merits a detailed investigation. In Aim 1, using immunohistochemical and Western blot analysis, we shall establish which specific carbohydrate ligands of selectins, if any, are expressed on the TM cells and in the aqueous humor of normal and glaucomatous eyes. In Aim 2, we shall determine whether the selectins/carbohydrate-mediated signaling promotes adhesion of TM cells to a variety of extracellular matrix molecules in vitro. The proposed studies will determine whether the selectin-based carbohydrate recognition system plays a role in the pathogenic mechanisms of aqueous outflow resistance in glaucoma.