The role of LTBP2 in glaucoma

总结： 已经建立了一种独特的具有LTBP 2自发突变的青光眼动物模型。这 基因与异质性青光眼表型有关，包括人类原发性先天性青光眼 (PCG)以及某些形式的成人型开角型青光眼。作为唯一已知的大型动物同系物 在人类遗传性青光眼中，该模型具有相当大的转化研究潜力。后 节段病理学已被广泛表征，并密切概括了人类 青光眼性视神经病变然而，LTBP 2在眼睛中所起的作用仍然未知， 导致潜在眼内压（IOP）升高的精确细胞和分子机制 这种形式的青光眼仍然没有得到解决。本建议的目的是确定和本地化， 治疗干预的潜在靶点，有助于早期和晚期癌症的关键病理生物学机制 在该模型中的发作和进行性IOP升高。除了扰乱LTBP2的公认作用， 微纤维组装，增强TGF β信号传导，促进细胞外基质（ECM）积累 在小梁网（TM）内的眼压升高被认为是这种情况下IOP升高的机制。 "微纤维病"。然而，在我们的动物模型的初步研究还没有建立是否显着 房水TGF β浓度增加代表IOP升高的原因或结果。我们的中央 一种假说认为LTBP 2是流出道发育和重构的重要调节因子， 以及TM细胞和ECM生物学和整个生命中的促纤维化途径的调节剂， 超越发展。我们将追求两个具体的目标：目标1：确定缺席的影响 或LTBP2表达减少对近端和远端房水流出途径的发展，我们将测试 LTBP2在流出途径的发展和重塑中起重要作用的假设， 结合体内和原位方法，检查远端流出道形态和超微结构， 近端流出途径（TM和近端小管组织）和野生型中这些途径的ECM组分 以及LTBP 2 +/-和LTBP 2-/-眼。目的2：确定LTBP 2缺失或减少的病理学作用 为了在TM细胞（TMC）生物学上表达，我们将使用来源于野生型、LTBP 2 +/-和LTBP 2-/-的TMC培养物， 眼睛在目标2中，我们将检验LTBP2表达减少将a）负面影响TMC的假设 B）增强TGF β对肌动蛋白细胞骨架的病理作用， 促进ECM纤维化。成功完成这些目标将产生新的知识复杂 LTBP2在水流出途径的生理学和病理学中的作用，提供了一个重要的基础， 推进我们的总体目标，设计和测试创新的治疗方法，以青光眼在我们独特的 平移模型

Summary: A unique animal model of glaucoma with spontaneously arising mutation in LTBP2 has been established. This gene is implicated in heterogeneous glaucoma phenotypes, including human primary congenital glaucoma (PCG) as well as some forms of adult-onset open angle glaucoma. As the only known large animal homolog of inherited glaucoma in humans, this model has considerable potential for translational research. Posterior segment pathology has been extensively characterized and closely recapitulates features of human glaucomatous optic neuropathy. However, the role played by LTBP2 in the eye remains unknown and the precise cellular and molecular mechanisms responsible for the underlying elevated intraocular pressure (IOP) in this form of glaucoma remain unresolved. The objective of this proposal is to identify and localize, as potential targets for therapeutic intervention, key pathobiological mechanisms that contribute to both early onset and progressive IOP elevation in this model. In addition to perturbing LTBP2’s acknowledged role in microfibril assembly, enhanced TGF beta signaling, contributing to extracellular matrix (ECM) accumulation within the trabecular meshwork (TM) has been proposed as a mechanism for IOP elevation in this “microfibrillopathy”. However, preliminary studies in our animal model have not established whether significant increase in aqueous humor TGF beta concentrations represent a cause or effect of IOP elevation. Our central hypothesis is that LTBP2 is both an important regulator of outflow pathway development and remodeling in the perinatal period and a regulator of TM cell and ECM biology and pro-fibrotic pathways throughout life, extending beyond development. We will pursue two specific Aims: Aim 1: To determine the effects of absent or reduced LTBP2 expression on development of proximal and distal aqueous outflow pathways, we will test the hypothesis that LTBP2 plays an important role in outflow pathway development and remodeling using a combination of in vivo and in situ approaches to examine distal outflow morphology and ultrastructure of the proximal outflow pathway (TM and juxtacanalicular tissue) and ECM components of these pathways in wildtype and LTBP2+/- and LTBP2-/- eyes. Aim 2: To determine the pathological effects of absent or reduced LTBP2 expression on TM cell (TMC) biology, we will use TMC cultures derived from wildtype, LTBP2+/- and LTBP2-/- eyes. In Aim 2, we will test the hypotheses that reduced LTBP2 expression will a) negatively impact TMC attachment and proliferation in vitro and b) enhance the pathologic effects of TGFβ on actin cytoskeleton and promotion of ECM fibrosis. Successful completion of these Aims will generate new knowledge on the complex role of LTBP2 in physiology and pathology of the aqueous outflow pathways, providing a critical foundation to advance our overall goal of designing and testing innovative therapeutic approaches to glaucoma in our unique translational model.