经典Wnt信号通路诱发EMT促进糖尿病视网膜病纤维化发生的机制

Fibrosis is main pathological characteristic of blindness in diabetic retinopathy. Our previous studies have shown that the canonical Wnt signaling pathway is activated in diabetic retinopathy and nephropathy in animal models of diabetes and blockade of the canonical Wnt signaling pathway attenuates tissue fibrosis, strongly suggesting the activation of canonical Wnt signaling pathway promotes fibrosis. However, the mechanism is still unclear. EMT is closely related to the fibrosis in kidney, lung and liver,while whether the EMT is involved in the fibrosis of diabetic retinopathy has not been reported. Our preliminary results indicate the occurrence of EMT in experimental diabetic retinopathy. This study is designed to further prove the EMT occurrence in diabetic retinopathy and clarify the mechanism responsible for EMT in retina fibrosis. On the other hand, Wnt signaling pathway mediates EMT and Our preliminary results show that activation of canonical Wnt signaling pathway can cause retinal pigment epithelial cells to undergo EMT. Therefore, this study is also to enlucidate the mechanism by which the canonical Wnt signaling pathway induces EMT in diabetic retinopathy. The purpose of this project is to elucidate the canonical Wnt signaling pathway mediated-EMT promotes retinal fibrosis of diabetic retinopathy, and it is of important value to further understand the pathogenesis of fibrosis and to search effective therapeutic targets for diabetic retinopathy.

糖尿病视网膜病纤维化增生是其致盲的基本病理表现。我们以往研究发现，经典Wnt信号通路在糖尿病视网膜病和肾病中过度激活，阻断Wnt信号通路可以减弱组织纤维化，提示Wnt信号通路激活促进纤维化发生，但机制尚不清楚。EMT发生与肾脏、肺脏以及肝脏纤维化紧密相关，而EMT是否介导糖尿病视网膜病的纤维化尚未报导；我们的预实验结果初步显示糖尿病视网膜病存在EMT；本项目拟进一步证实糖尿病视网膜病中EMT的发生并阐明EMT导致视网膜纤维化发生的机制。另一方面，Wnt信号通路是介导EMT的主要信号通路，我们以往研究显示Wnt信号通路的激活，预实验结果进一步提示Wnt激活可引起视网膜色素上皮细胞发生EMT；本项目拟阐明Wnt信号通路诱发视网膜EMT发生的机制。旨在明确Wnt信号通路过度激活通过诱发EMT促进糖尿病视网膜病视网膜纤维化，对于充分理解糖尿病视网膜病纤维化发病机制和寻找有效治疗靶点具有重要价值。

本项目对糖尿病视网膜EMT的发生和介导视网膜纤维化以及EMT发生的机制进行了系统的研究。关于糖尿病视网膜EMT的发生：体内实验采用增殖性糖尿病视网膜病人的手术前膜标本以及1型和2型糖尿病动物模型视网膜，体外实验采用高糖和糖基化终末产物处理视网膜色素上皮细胞和Müller细胞，通过检测EMT的标记分子明确糖尿病视网膜EMT的发生。关于EMT导致视网膜纤维化的发生：过表达snail和N-cadherin，引起视网膜色素上皮细胞和Müller细胞中纤维化因子CTGF和Fibronectin的表达上调；干扰snai和N-cadherinl可以降低细胞中因高糖引起的CTGF和Fibronectin的表达上调。关于糖尿病视网膜EMT发生的机制：wnt信号通路的激活可以引起视网膜色素上皮细胞和Müller细胞EMT分子的变化，另外，AKT和ERK通路介导调EMT分子的变化。本项目初步证实糖尿病视网膜病中EMT的发生并介导视网膜纤维化及其相关机制，对于充分理解糖尿病视网膜病纤维化发病机制和寻找有效治疗靶点具有重要价值。