Integrin Signaling in the Trabecular Meshwork

描述(申请人提供)：这是一份新的R01申请。这笔赠款的长期目标是确定可用作控制和降低眼压的治疗靶点的整合素信号机制。青光眼会导致视网膜神经节细胞不可逆转的丧失，全球约有6700万人受到影响。它们通常与由于小梁网(TM)房水流出减少而导致的眼内压(IOP)升高有关。虽然已知有许多生理因素调节流出设施，但作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，还不清楚哪些分子事件调节TM的收缩能力。我们实验室的研究表明，细胞外基质(ECM)及其受体(整合素)的生物活性片段的信号特性可用于调节TM的收缩能力，并增加培养的前节段的流出能力。特别是，我们已经证明了纤维连接蛋白的一个生物活性结构域，称为HepII结构域，激活了一个？4？1整合素信号通路，降低了培养的TM细胞的细胞收缩能力。我们的初步数据有力地支持了这样的假设，即在TM中操纵整合素信号通路来改变细胞的收缩能力可以用来调节流出设施。这项研究的目的是确定在TM中靶向整合素信号通路的可能方法，以增加流出设施。为此，我们提出了三种方法来激活培养的前节细胞中的？4？1信号通路。首先，使用慢病毒载体在TM中表达微小的HepII基因。第二，在TM中过表达一个结构性激活的整合素β4亚基。第三，表达来自β4-亚基或整合素结合蛋白的细胞质区域的多肽，它可以破坏细胞黏附并降低细胞的收缩能力。在这一应用中提出的研究不仅将加强我们对整合素信号在TM中的作用的理解，而且它将发现针对TM中细胞收缩的新方法。 与公共健康相关：青光眼是美国第二大致盲原因，也是非裔美国人致盲的最常见原因。眼压升高是青光眼的常见危险因素。本项目的目标是寻找能够被激活以降低眼压的信号通路(S)，并将其作为治疗青光眼的潜在靶点。

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.