Control of Trabecular Meshwork Cytoskeleton

青光眼是一种影响全球近6700万人的视神经病变。它通常与眼压升高有关，这是由于小梁网流出的房水减少所致。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新的靶点。整合素/syndecan介导的信号通路在调节肌动蛋白细胞骨架中起关键作用。我们提出整合素和/或syndecans有助于肌动蛋白细胞骨架和流出设施的调节，这些受体可能负责在类固醇治疗后观察到的细胞骨架的变化（即CLAN形成）。我们进一步提出，类固醇治疗激活了这些信号通路，因为它导致细胞外配体或细胞质信号分子与整合素和syndecans相关的上调。这项资助的主要目的是确定整合素和syndecans在控制TM中肌动蛋白细胞骨架的组织中所起的作用，以及它们可以在多大程度上被操纵来调节流出设施。该资助的目的是：(1)通过使用整合素特异性肽（激动剂和拮抗剂）和激活或抑制抗体来阻断或触发CLAN形成，确定负责TM中CLAN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)通过使用syndecan-4 siRNA和在TM细胞培养中过表达全长或截断的syndecan-4，通过阻断或增强其正常功能，证明syndecan-4是TM中肌动蛋白网络的关键调节因子；(4)确定病毒向syndecan-4表达发卡siRNA序列是否会阻断类固醇诱导的家族形成和流出设施的减少；(5)确定类固醇治疗是否会影响蛋白质(Rac1, Tiam1, Trio， PI-3激酶，Src, PIP2)与这些通路相关。最终，这些知识可用于开发治疗或预防POAG或类固醇性青光眼的新疗法。

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.