PDF(Pubmed)
Abstract：
Pathological alterations in the biomechanical properties of the Schlemm\'s canal (SC) inner wall endothelium and its immediate vicinity are strongly associated with ocular hypertension in glaucoma due to decreased outflow facility. Specifically, the underlying trabecular meshwork is substantially stiffer in glaucomatous eyes compared with that from normal eyes. This raises the possibility of a critical involvement of mechanotransduction processes in driving SC cell dysfunction. Yes-associated protein (YAP) has emerged as a key contributor to glaucoma pathogenesis. However, the molecular underpinnings of SC cell mechanosignaling via YAP and transcriptional coactivator with PDZ-binding motif (TAZ) in response to glaucomatous extracellular matrix (ECM) stiffening are not well understood. Using a novel biopolymer hydrogel that facilitates dynamic and reversible stiffness tuning, we investigated how ECM stiffening modulates YAP/TAZ activity in primary human SC cells, and whether disruption of YAP/TAZ mechanosignaling attenuates SC cell pathobiology and increases ex vivo outflow facility. We demonstrated that ECM stiffening drives pathologic YAP/TAZ activation and cytoskeletal reorganization in SC cells, which was fully reversible by matrix softening in a distinct time-dependent manner. Furthermore, we showed that pharmacologic or genetic disruption of YAP/TAZ mechanosignaling abrogates stiffness-induced SC cell dysfunction involving altered cytoskeletal and ECM remodeling. Finally, we found that perfusion of the clinically used, small molecule YAP/TAZ inhibitor verteporfin (without light activation) increases ex vivo outflow facility in normal mouse eyes. Collectively, our data provide new evidence for a pathologic role of aberrant YAP/TAZ mechanosignaling in SC cell dysfunction and suggest that YAP/TAZ inhibition has therapeutic value for treating ocular hypertension in glaucoma.NEW & NOTEWORTHY Pathologically altered biomechanical properties of the Schlemm\'s canal (SC) inner wall microenvironment were recently validated as the cause for increased outflow resistance in ocular hypertensive glaucoma. However, the involvement of specific mechanotransduction pathways in these disease processes is largely unclear. Here, we demonstrate that Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) are central regulators of glaucoma-like SC cell dysfunction in response to extracellular matrix stiffening and that targeted disruption of YAP/TAZ mechanosignaling attenuates SC cell pathobiology and enhances outflow function.
摘要：
Schlemm管（SC）内壁内皮及其附近的生物力学特性的病理学改变与青光眼的高眼压密切相关，这是由于流出设施减少所致。具体来说,与正常眼相比，青光眼眼的潜在小梁网明显更硬。这提高了机械转导过程在驱动SC细胞功能障碍中的关键参与的可能性。Yes相关蛋白（YAP）已成为青光眼发病机理的关键因素。然而,通过YAP和具有PDZ结合基序的转录共激活因子(TAZ)响应青光眼细胞外基质(ECM)硬化的SC细胞机械信号的分子基础尚不清楚.使用新型生物聚合物水凝胶，促进动态和可逆刚度调整，我们研究了ECM硬化如何调节原代人SC细胞中的YAP/TAZ活性，以及YAP/TAZ机械信号的破坏是否减弱SC细胞病理学并增加离体流出设施。我们证明，ECM硬化驱动病理性YAP/TAZ激活和细胞骨架重组在SC细胞，通过基质软化以明显的时间依赖性方式完全可逆。此外，我们发现YAP/TAZ机械信号的药理学或遗传学破坏消除了僵硬诱导的SC细胞功能障碍,涉及细胞骨架和ECM重塑的改变.最后,我们发现临床使用的灌注，小分子YAP/TAZ抑制剂维替泊芬（无光激活）增加正常小鼠眼中的离体流出设施。总的来说，我们的数据为异常YAP/TAZ机械信号在SC细胞功能障碍中的病理作用提供了新的证据,并提示YAP/TAZ抑制对青光眼高眼压有治疗价值.
