Control of Trabecular Meshwork Cytoskeleton

描述：青光眼是一种视神经疾病，全世界有近6700万人受到影响。它通常与由于小梁网(TM)房水流出减少而导致的眼内压升高有关。最近的研究表明，肌动蛋白细胞骨架对房水流出有深远的影响，因此可能为青光眼的治疗提供一个新的靶点。整合素/Syndecan介导的信号通路在肌动蛋白细胞骨架的调控中起着关键作用。我们认为整合素和/或合十蛋白参与了肌动蛋白细胞骨架和外流设施的调节，这些受体可能是类固醇治疗后观察到的细胞骨架变化(即家族形成)的原因。我们进一步认为，类固醇治疗激活这些信号通路是因为它引起与整合素和合并素相关的细胞外配体或细胞质信号分子的上调。这笔赠款的主要目的是确定整合素和同步蛋白在管理TM中肌动蛋白细胞骨架的组织中所起的作用，以及可以在多大程度上操纵它们来调节流出设施。这项资助的目的是(1)通过使用整合素特定的多肽(激动剂和拮抗剂)以及激活或抑制抗体来阻断或触发部族形成来确定负责TM肌动蛋白网络形成的特定整合素，(2)使用整合素拮抗剂和激动剂来证明特定的整合素信号通路影响流出设施，特别是在类固醇治疗的眼睛中，(3)证明Syndecan-4是TM中肌动蛋白网络的关键调节因子，通过使用syndecan-4 siRNA阻断或增强其正常功能，并在TM细胞培养中过表达全长或截短syndecan-4，(4)确定病毒表达的针对syndecan-4的发夹siRNA序列是否会阻止类固醇诱导的家族形成和减少流出能力，以及(5)确定类固醇处理是否影响与这些途径相关的蛋白质(rac1、Tiam1、Trio、PI-3 Kinase、Src、PIP2)的表达或活性。最终，这些知识可以用来开发新的治疗方法来治疗或预防POAG或类固醇诱导的青光眼。

DESCRIPTION: Glaucoma is an optic neuropathy that affects nearly 67 million people world-wide. It is commonly associated with elevated levels of intraocular pressure due to a reduction in aqueous humor outflow from the trabecular meshwork (TM). Recent studies indicate that the actin cytoskeleton has a profound influence on aqueous humor outflow and thus might provide a new target for the treatment for glaucoma. Integrin/syndecan mediated signaling pathways play a critical role in regulating the actin cytoskeleton. We propose that integrins and/or syndecans contribute to the regulation of the actin cytoskeleton and outflow facility and that these receptors may be responsible for changes in the cytoskeleton (i.e., CLAN formation) observed after steroid treatment. We further propose that steroid treatment activates these signaling pathways because it causes an upregulation of extracellular ligands or cytoplasmic signaling molecules associated with integrins and syndecans. The main objectives of this grant are to determine the role that integrins and syndecans play in governing the organization of the actin cytoskeleton in the TM and the extent to which they can be manipulated to regulate outflow facility. The aims of this grant are (1) determine the specific integrins responsible for the formation of CLANs in TM by using integrin specific peptides (agonists and antagonists) and activating or inhibiting antibodies to block or trigger CLAN formation, (2) use integrin antagonists and agonists to demonstrate that specific integrin signaling pathways influence outflow facility, especially in steroid treated eyes, (3) demonstrate that syndecan-4 is a key regulator of actin networks in the TM by blocking or enhancing its normal function using syndecan-4 siRNA and overexpression of full length or truncated syndecan-4 in TM cell cultures, (4) determine if virally expressed hairpin siRNA sequences to syndecan-4 would block steroid induced clan formation and decreases in outflow facility, and (5) determine if steroid treatment affects the expression or activity of proteins (Rac1, Tiam1, Trio, PI-3 kinase, Src, PIP2) associated with these pathways. Ultimately, this knowledge can be used to develop new therapies to treat or prevent POAG or steroid-induced glaucoma.