Piezo2/Ca2+介导成纤维细胞表型转化在近视巩膜重塑中的作用及力学响应机制

Scleral remodeling and its mechanical property changes are the basis of axial elongation of myopia. However, the mechanism of such processes still remains unknown. Recently, our research group found that fibroblast differentiation and Piezo2, mechanically sensitive ion channel, are significantly up-regulated in the guinea pig sclera of form-deprivation myopia (FDM). But its role in scleral remodeling is still unclear. Therefore, we apply gain-of-function and loss-of-function in guinea pig FDM and fibroblast mechanical loading models, firstly, to elucidate the role of fibroblast differentiation in myopia scleral remodeling; Secondly, we aim to reveal if Piezo2 channel can regulate the influx of calcium and its downstream Calpain and RhoA, which further lead to fibroblast differentiation in myopia sclera. Finally, we target Piezo2 channel for intervention, to explore if it could be a potential therapeutic target in regulating myopia scleral remodeling. Our study may enrich the perspective in biomechanical mechanism of fibroblast differentiation and scleral remodeling, and provide with theoretical evidence for prevention and treatment in myopia.

巩膜重塑、力学性能改变是近视眼轴延长的基础，然机制不明。本课题组新近研究发现豚鼠形觉剥夺性近视巩膜成纤维细胞转化为肌成纤维细胞增多，且细胞膜机械敏感性离子通道Piezo2表达增加，但其在调控巩膜重塑中的机制未见报道。为此，本课题通过豚鼠近视模型和细胞力学加载模型，运用基因功能获得及功能丧失等技术，首先研究成纤维细胞表型转化对近视巩膜重塑的作用；其次阐明细胞膜Piezo2离子通道-细胞外Ca2+内流-活化钙蛋白酶Calpain及RhoA在将细胞外应变力信号转化为细胞内生物学信号、调控成纤维细胞表型转化中的作用；最后回归在体动物，以Piezo2为靶标进行干预，探讨其在调控近视巩膜重塑作用中的转化潜力。本课题的研究结果可能丰富人们对成纤维细胞表型转化在近视巩膜重塑中的关键作用及其力学生物学机制的认识，为近视防治提供理论基础和潜在的治疗靶点。

近视已成为世界范围内的常见病、多发病。巩膜是异常视觉信号作用的终端靶效应器，决定着眼球的大小和形态。在近视的形成与发展过程中，巩膜结构及力学性能发生重塑。从力学层面研究巩膜的重塑机制，寻找阻断巩膜重塑的关键靶点是近视防治的关键问题。本课题在前期研究工作的基础上，通过体外加载应变力刺激巩膜成纤维细胞，研究巩膜重塑的力学分子学机制。并通过体内外实验干预Piezo2/Ca2+/RhoA信号通路，研究力学生物学信号通路对实验性近视巩膜重塑的调控机制。本研究发现：豚鼠形觉剥夺性近视巩膜组织中α-SMA表达增加，且Piezo2、RhoA信号分子表达增加，对巩膜力学特性的研究发现实验性近视巩膜极限应变增加。进一步体外巩膜成纤维细胞加载应变力刺激结果表明，应变力可以促进Piezo2、RhoA、α-SMA表达，细胞外Ca2+内流增加，细胞内Calpain1活性增加。体外应用抑制剂、无Ca2+培养基、SiRNA干扰技术分别干预Piezo2、Ca2+、RhoA表达可以调控α-SMA表达。本研究明确了Piezo2/Ca2+力学信号通路在实验性近视巩膜重塑中的作用及意义，为近视防治提供了新的干预靶点。