Integrinα2β1-YAP/TAZ介导的力学生物学信号转导在近视巩膜重塑中的作用

Scleral remodeling and its elasticity decrease are the final processes of the axial length elongation in myopia. However, the mechanism of these processes still remains unknown. Recently, our study group found that Integrinα2β1, a protein that mediating mechano-biological signaling transduction is significantly down-regulated in the sclera of form deprivation myopia (FDM) mice, and its change is correlated with myopic degree. But the role of Integrinα2β1 is unclear. Therefore, we apply gene knock-out and recombination technique in mice FDM and 3-D soft substratum cell culture model, firstly, to elucidate if Integrinα2β1 can regulate YAP/TAZ pathway and its downstream collagen metabolic molecular by RhoA pathway, which lead to elasticity modulus decrease and scleral axial length elongation; Secondly, if down-regulated Integrinα2β1 can influence cell-mediated collagen gel’s contraction and YAP/TAZ by regulating the reconstruction of cellular skeleton protein (F-actin). Then, we target Integrinα2β1-YAP/TAZ for intervention, to reveal if it could be a potential therapeutic target in myopic control. To the best of our knowledge, no related research has been published by now. Our study may enrich the perspective in biomechanics of scleral remodeling, and provide with both theoretical and experimental evidence for prevention and treatment in myopia.

巩膜重塑、弹性承载力降低是近视眼轴延长的最终环节，然而机制不完全清晰。最近，本课题组发现，介导力学生物学信号转导的Integrinα2β1在形觉剥夺近视小鼠巩膜组织中显著下调，且与近视度数相关，但作用不明。为此，本课题对近视动物模型和培养于3D软性基质的细胞模型，运用基因敲除及重组技术，首先研究下调的Integrinα2β1是否通过RhoA调节YAP/TAZ使下游的胶原代谢相关因子表达减少，导致巩膜弹性模量下降、眼轴延长，其次阐明Integrinα2β1是否通过胞浆骨架蛋白(F-actin)重构影响细胞收缩力并调控YAP/TAZ起作用，进而，以Integrinα2β1-YAP/TAZ为靶标进行干预，揭示其可能是近视治疗的有效靶点。迄今，这些研究在国际上尚属空白，其预期的研究结果可能丰富人们对近视巩膜重塑中力学生物学机制的认识，为近视防治提供理论和实验依据，具有重要的理论和现实意义。

近视（Myopia）是目前世界范围内的常见病，可造成不可逆性视力损害。近视巩膜基质重塑引起巩膜扩张、变薄，导致眼轴过度延长是近视最主要的病理变化。然而，近视巩膜基质重塑的分子生物学调控机制尚未完全阐明。最近研究认为，巩膜生物力学变化在近视发生发展中起重要作用，但其对巩膜重塑的作用尚不明确。本研究的主要目的为探讨Integrinα1β1-YAP介导的力学生物学信号转导在近视巩膜基质重塑中的作用，阐明细胞外基质硬度这一力学信号调控巩膜成纤维I型胶原形成的分子机制，为近视的干预和治疗寻找新的靶点。本项目首先，建立豚鼠形觉剥夺近视（Form-deprivation myopia,FDM）模型，发现其巩膜组织中Integrinα1β1表达下调，活化的YAP减少。其次，在离体细胞实验中，用硬性和软性基质模拟正常和FDM巩膜组织硬度，对Integrinα1β1、F-actin、YAP多个靶点进行干预，结果发现ECM基质硬度降低通过下调Integrinα1β1表达，使巩膜成纤维细胞中FAs形成及F-actin聚合减少，进而使YAP入核减少，YAP转录活性下降，最终使COL1A1的表达下调。最后，通过在体干预实验，证实干预F-actin、YAP影响实验性近视动物模型近视进展和眼轴延长，可作为近视治疗的潜在靶点。本研究明确了Integrinα1β1-YAP力学信号通路在实验性近视巩膜重塑中的变化及意义，阐明力学信号改变调控巩膜重塑的机制，为近视防治提供了新的干预靶点。