Autotaxin-Lysophosphatidic Acid Axis Is a Novel Molecular Target for Lowering Intraocular Pressure
Autotaxin-Lysophosphatidic Acid Axis Is a Novel Molecular Target for Lowering Intraocular Pressure
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DOI：
10.1371/journal.pone.0042627
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发表时间：
2012-08-20
期刊：
影响因子：
3.7
通讯作者：
Rao, Ponugoti Vasantha
中科院分区：
文献类型：
--
作者：
Iyer, Padma;Lalane, Robert, III;Rao, Ponugoti Vasantha
原发性开角型青光眼是美国第二大失明原因，通常与通过小梁通路的房水 (AH) 引流减少导致的眼内压 (IOP) 升高有关。开发针对青光眼患者 IOP 增加的有效疗法需要识别和表征调节 IOP 和 AH 流出的分子机制。本研究描述了自分泌运动蛋白 (ATX) 的鉴定和作用，它是一种分泌蛋白，也是细胞外溶血磷脂酸 (LPA) 的主要来源，在兔模型中调节 IOP 中的作用。定量蛋白质组学分析发现，ATX 在来自非青光眼受试者的人类 AH 和来自不同动物物种的 AH 中都是丰富的蛋白质。与来自年龄匹配的白内障对照患者的 AH 相比，来自人类原发性开角型青光眼患者的 AH 中 ATX 的溶血磷脂酶 D (LysoPLD) 活性显着升高（大约 1.8 倍；n = 20）。对源自人小梁网 (HTM) 细胞原代培养物的条件培养基的免疫印迹分析证实了 ATX 的分泌以及 TM 细胞的循环机械拉伸增加分泌的 ATX 水平的能力。局部应用 ATX 小分子化学抑制剂 (S32826)，在体外抑制 AH LysoPLD 活性（>90%），导致荷兰带兔的 IOP 呈剂量依赖性显着降低。单次前房注射S32826（大约2μM）可显着降低兔子的眼压，降眼压反应持续超过48小时。使用小干扰 RNA (siRNA) 抑制 HTM 细胞中的 ATX 表达，导致肌动蛋白应激纤维和肌球蛋白轻链磷酸化减少。总的来说，这些观察结果表明 ATX-LPA 轴代表了青光眼患者降低 IOP 的潜在治疗靶点。
Primary open-angle glaucoma is the second leading cause of blindness in the United States and is commonly associated with elevated intraocular pressure (IOP) resulting from diminished aqueous humor (AH) drainage through the trabecular pathway. Developing effective therapies for increased IOP in glaucoma patients requires identification and characterization of molecular mechanisms that regulate IOP and AH outflow. This study describes the identification and role of autotaxin (ATX), a secretory protein and a major source for extracellular lysophosphatidic acid (LPA), in regulation of IOP in a rabbit model. Quantitative proteomics analysis identified ATX as an abundant protein in both human AH derived from non-glaucoma subjects and in AH from different animal species. The lysophospholipase D (LysoPLD) activity of ATX was found to be significantly elevated (by similar to 1.8 fold; n = 20) in AH derived from human primary open angle glaucoma patients as compared to AH derived from age-matched cataract control patients. Immunoblotting analysis of conditioned media derived from primary cultures of human trabecular meshwork (HTM) cells has confirmed secretion of ATX and the ability of cyclic mechanical stretch of TM cells to increase the levels of secreted ATX. Topical application of a small molecular chemical inhibitor of ATX (S32826), which inhibited AH LysoPLD activity in vitro (by >90%), led to a dose-dependent and significant decrease of IOP in Dutch-Belted rabbits. Single intracameral injection of S32826 (similar to 2 mu M) led to significant reduction of IOP in rabbits, with the ocular hypotensive response lasting for more than 48 hrs. Suppression of ATX expression in HTM cells using small-interfering RNA (siRNA) caused a decrease in actin stress fibers and myosin light chain phosphorylation. Collectively, these observations indicate that the ATX-LPA axis represents a potential therapeutic target for lowering IOP in glaucoma patients.