Integrin Signaling in the Trabecular Meshwork

描述（由申请人提供）：这是一份新的R01申请。该资助的长期目标是确定整合素信号机制，可作为控制和降低眼压的治疗靶点。青光眼导致视网膜神经节细胞不可逆转的丧失，全世界约有6700万人患有青光眼。它们通常与眼内压（IOP）水平升高有关，这是由于房水从小梁网（TM）流出减少所致。虽然已知有许多生理因素调节流出设施，但已成为流出设施重要调节机制的关键因素之一是TM的收缩特性。目前，还不清楚是什么分子事件调节了TM的收缩性。我们实验室的研究表明，来自细胞外基质（ECM）及其受体（整合素）的生物活性片段的信号传导特性可用于调节TM的收缩性并增加培养前节段的流出设施。特别是，我们已经证明了纤维连接蛋白的生物活性结构域称为HepII结构域激活？1整合素信号通路降低培养的TM细胞的细胞收缩性。我们的初步数据有力地支持了这样的假设，即对TM中整合素信号通路的操纵可以改变细胞的收缩性，从而调节流出设施。本研究的目的是确定可能的方法来靶向TM中的整合素信号通路，以增加流出设施。为此，我们提出了三种方法来激活？1信号通路的培养前节段。首先，使用慢病毒载体在TM中表达mini-HepII基因。第二，过度表达构成激活？TM中的4个整合素亚基。第三，从？细胞质结构域表达多肽。4亚基或整合素结合蛋白，paxillin破坏细胞粘附和降低细胞收缩性。本应用程序中提出的研究不仅将增强我们对整合素信号在TM中的作用的理解，而且将确定靶向TM细胞收缩性的新方法。

DESCRIPTION (provided by applicant): This is a new application for a R01. The long-term objective of this grant is to identify integrin signaling mechanisms that can be used as therapeutic targets to control and lower intraocular pressure. The glaucomas, which lead to irreversible loss of retinal ganglion cells, affect approximately 67 million people worldwide. They are commonly associated with elevated levels of intraocular pressure (IOP) due to a reduction in aqueous humor outflow from the trabecular meshwork (TM). Although a number of physiological factors are known to regulate outflow facility, one of the key factors that have emerged as an important regulatory mechanism for outflow facility is the contractile properties of the TM. At the present, it is unclear what molecular events regulate contractility in the TM. Studies from our laboratory have shown that the signaling properties of bioactive fragments from the extracellular matrix (ECM) and their receptors (integrins) can be used to regulate the contractility of the TM and increase outflow facility in cultured anterior segments. In particular we have shown that a bioactive domain from fibronectin called the HepII domain activates a ?4?1 integrin signaling pathway that decreases cell contractility in cultured TM cells. Our preliminary data strongly supports the hypothesis that manipulation of integrin signaling pathways in the TM that modify cellular contractility can be used to regulate outflow facility. The objective of this research is to identify possible ways to target integrin signaling pathways in the TM in order to increase outflow facility. To this end, we propose three approaches to activate the ?4?1 signaling pathway in cultured anterior segments. First, use lentiviral vectors to express a mini-HepII gene in the TM. Second, over express a constitutively activated ?4 integrin subunit in the TM. Third, express peptides from the cytoplasmic domain of the ?4-subunit or the integrin binding protein, paxillin which disrupt cell adhesion and decrease cell contractility. The studies proposed in this application will not only enhance our understanding of the role of integrin signaling in the TM, but it will identify new ways to target cell contractility in the TM. PUBLIC HEALTH RELEVANCE: Glaucoma is the second most common cause of blindness in the U.S. and the most common cause of blindness among African-Americans. Increased intraocular pressure (IOP) is a common risk factor for glaucoma. The goal of this project is to identify signaling pathway(s) that can be activated to reduce IOP and be used as potential targets to treat glaucoma.