Control of Trabecular Meshwork Cytoskeleton

青光眼是一种视神经病变，影响全球近6700万人。它通常与眼内压水平升高有关，这是由于小梁网（TM）的房水流出减少所致。近年来的研究表明，肌动蛋白细胞骨架对房水流出有着重要的影响，可能为青光眼的治疗提供新的靶点。整合素/多配体蛋白聚糖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/或多配体蛋白聚糖有助于调节肌动蛋白细胞骨架和流出设施，并且这些受体可能负责细胞骨架的变化（即，CLAN形成）。我们进一步提出，类固醇治疗激活这些信号通路，因为它会导致与整合素和多配体蛋白聚糖相关的细胞外配体或细胞质信号分子的上调。 这项赠款的主要目标是确定的作用，整合素和syndecans发挥在管理组织的肌动蛋白细胞骨架在TM和在何种程度上可以操纵，以调节流出设施。本研究的目的是：（1）利用整合素特异性肽确定TM中负责形成CLANs的特异性整合素（激动剂和拮抗剂）和激活或抑制抗体以阻断或触发CLAN形成，（2）使用整联蛋白拮抗剂和激动剂来证明特异性整联蛋白信号传导途径影响流出功能，特别是在类固醇治疗的眼中，（3）通过在TM细胞培养物中使用多配体蛋白聚糖-4 siRNA和全长或截短的多配体蛋白聚糖-4的过表达来阻断或增强其正常功能，证明多配体蛋白聚糖-4是TM中肌动蛋白网络的关键调节剂，（4）确定病毒表达的针对多配体蛋白聚糖-4的发夹siRNA序列是否会阻断类固醇诱导的族形成和流出便利性的降低，和（5）确定类固醇治疗是否影响与这些途径相关的蛋白质（Rac 1、Tiam 1、Trio、PI-3激酶、Src、PIP 2）的表达或活性。最终，这些知识可以用于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.