Pressure Regulation of Human Trabecular Meshwork Genes

描述（由申请人提供）：青光眼是一种导致不可逆失明的视神经病变。我们研究青光眼的方法包括选择一个与疾病相关的成熟的临床条件，并在分子水平上研究临床参数。高眼压（IOP）是青光眼发生的主要危险因素。在人类中，90%的房水通过小梁网（TM）离开眼睛。因此，功能障碍的TM导致阻力增加和IOP升高。由于组织的生理学受其基因表达的控制，在先前的资助周期中，我们检查了在IOP升高的条件下TM的差异表达。在分析了许多芯片阵列比较正常和高眼压灌注死后人眼，我们解开了一些基因参与钙化过程。我们进一步发现，这些过程不仅存在于TM中，而且它们似乎在来自昏迷患者的TM中更活跃。基于这些发现，我们假设TM钙化与IOP和流出道功能的调节有关。控制骨和血管组织中生理和病理钙化的基因和机制在TM中是活跃的，这些过程以及抑制它们的努力是控制房水流出的调节系统的一部分。我们进一步假设，未能保持TM矿化检查将影响沉积的胶原蛋白和弹性蛋白交联与ECM硬化的有害后果。 为了验证这些假设，我们建议通过三种新的途径进一步表征所确定的机制。第一个将通过使用转基因小鼠来研究体内现象。第二部分将研究人体器官培养的过程。第三个将使用原代人类TM细胞来确定TM矿化中两种途径（WNT和LOX相关弹性蛋白/胶原交联）的参与。这两种途径与血管钙化和成骨细胞分化以及影响TM功能的条件独立相关。 这些假说的发展将为调节外流阻力的机制提供新的理解，并可能导致青光眼的新治疗方法。 公共卫生相关性：青光眼是不可逆失明的第二大原因，也是非洲裔美国人最常见的原因。青光眼的治疗方法有哪些？眼压升高是青光眼发生的主要危险因素。眼压是通过小梁网对房水流动的阻力来维持的。我们的项目的目标是调查的相关性，以前未描述的矿化过程中发生的小梁网的眼压调节。小梁网需要具有适当的分子机制，其将保持弹性、张力和柔软度的物理性质。保持柔软性与小梁网的功能最相关。 病理性钙化发生在软组织中，具有重要的临床意义。众所周知，异位钙化发生在心血管疾病、动脉粥样硬化、关节炎、肾脏疾病和癌症中。血管钙化降低了血管的弹性，增加了血管的脆性，导致动脉破裂的风险增加。在这个项目中，我们的目标是在转基因动物的眼睛，人类的眼睛死后捐赠者和初级小梁网细胞从角膜移植后的残留组织获得的这一过程的特点。我们将进一步研究钙化抑制剂在小梁网中的作用，并最终为青光眼的新治疗方法的开发打开一扇新的大门。

DESCRIPTION (provided by applicant): Glaucoma is an optic neuropathy which causes irreversible blindness. Our approach to study glaucoma consists of selecting a well-established clinical condition associated with the disease and investigating the clinical parameter at the molecular level. Elevated intraocular pressure (IOP) is the major risk factor for the development of glaucoma. In humans, 90% of the aqueous humor exits the eye through the trabecular meshwork (TM). Thus, a dysfunctional TM results in increased resistance and elevated IOP. Because the physiology of a tissue is governed by the expression of its genes, during the previous grant cycle we examined TM differential expression under conditions of elevated IOP. After analyzing many chip arrays comparing normal and high IOP perfuse post-mortem human eyes, we unraveled a number of genes involved in calcification processes. We further uncovered that such processes were not only present in the TM, but also that they seemed to be more active in TMs from glaucomatous patients. Based on these findings, we hypothesize that TM calcification is linked to regulation of IOP and outflow facility. That genes and mechanisms that govern physiological and pathological calcification in the bone and vascular tissues are active in the TM, and that these processes, as well as efforts to inhibit them, are part of the regulatory systems that control aqueous humor outflow. We further hypothesize that failure to maintain TM mineralization in check will affect deposited collagen and elastin cross-linking with deleterious consequences to ECM hardening. To test these hypotheses we propose to further characterize the identified mechanism through three new avenues. The first will investigate the phenomenon in vivo, through the use of transgenic mice. The second will investigate the process in human organ cultures. The third will use primary human TM cells to determine the involvement of two pathways (WNT and LOX-related elastin/collagen cross-linking) in TM mineralization. These two pathways have been independently associated with vascular calcification and osteoblastic differentiation and, with conditions affecting TM function. Results to be obtained with the development of these hypotheses will provide new understanding on the mechanisms regulating outflow resistance and would potentially lead to new treatments for glaucoma. PUBLIC HEALTH RELEVANCE: Glaucoma is the second leading cause of irreversible blindness and the most common cause among African- Americans. Currently, there is no cure for glaucoma. Elevated intraocular pressure (IOP) is the major risk factor for the developing of glaucoma. IOP is maintained by the resistance of the trabecular meshwork to the flow of aqueous humor. The goal of our project is to investigate the relevance of a previously undescribed process of mineralization occurring in the trabecular meshwork for the regulation of IOP. The trabecular meshwork needs to have in place molecular mechanisms that would maintain the physical properties of elasticity, tension and softness. Maintenance of the softness is of highest relevance to the trabecular meshwork's function. Pathological calcification occurs in soft tissues and has important clinical implications. Ectopic calcifications are well known to occur in cardiovascular diseases, atherosclerosis, arthritis, kidney disease and cancers. Vascular calcification decreases elasticity of the blood vessels and increases their brittleness, leading to increase risk of arterial rupture. In this project we aim to characterize this process in the eye of transgenic animals, human eyes from post-mortem donors and primary trabecular meshwork cells obtained from residual tissue after corneal transplants. We will aim to further study the role of inhibitors of calcification in the trabecular meshwork and ultimate open a new door for the development of new treatments for Glaucoma.