Weng Jie, Chen Zhenfeng, Li Jieyu, He Qi, Chen Deshu, Yang Lin, Su Haiying, Huang Junlin, Yu Shengxiang, Huang Qiaobing, Xu Qiulin, Guo Xiaohua
Department of Pulmonary and Critical Care Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
Department of Pathophysiology, Guangdong Provincial Key Laboratory of Shock and Microcirculation, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.
J Cell Mol Med. 2021 Aug;25(16):7746-7759. doi: 10.1111/jcmm.16659. Epub 2021 Jul 5.
Endothelial hyperpermeability is the initial event in the development of diabetic microvascular complications, and advanced glycation end products (AGEs) are suggested to cause much of the endothelial hyperpermeability associated with diabetes mellitus, but the molecular mechanism remains to be characterized. β-catenin reportedly plays dual functions in maintaining normal endothelial permeability by serving both as an adhesive component and a signal transduction component. Here, we found that AGEs induced the phosphorylation of β-catenin at residues Y654 and Y142 and the endothelial hyperpermeability was reversed when the two residues were blocked. In mechanism, phosphorylation of Y654 was blocked by Src inactivation, whereas phosphorylation of Y142 was reduced by a focal adhesion kinase inhibitor. β-catenin Y654 phosphorylation induced by AGEs facilitated the dissociation of vascular endothelial (VE)-cadherin/β-catenin and the impairment of adherens junctions (AJs), whereas β-catenin Y142 phosphorylation favoured the dissociation of β-catenin and α-catenin. Further investigation revealed that β-catenin Y142 phosphorylation was required for AGEs-mediated β-catenin nuclear translocation, and this nuclear-located β-catenin subsequently activated the TCF/LEF pathway. This pathway promotes the transcription of the Wnt target, ADAM10 (a disintegrin and metalloprotease 10), which mediates VE-cadherin shedding and leads to further impairment of AJs. In summary, our study showed the role of β-catenin Y654 and Y142 phosphorylation in AGEs-mediated endothelial hyperpermeability through VE-cadherin/β-catenin/α-catenin dissociation and up-regulation of ADAM10, thereby advancing our understanding of the underlying mechanisms of AGEs-induced microvascular hyperpermeability.
内皮细胞高通透性是糖尿病微血管并发症发生发展的起始事件，晚期糖基化终末产物（AGEs）被认为是导致糖尿病相关内皮细胞高通透性的主要原因，但其分子机制仍有待阐明。据报道，β-连环蛋白在维持正常内皮细胞通透性方面具有双重功能，它既是一种黏附成分，也是一种信号转导成分。在此，我们发现AGEs诱导β-连环蛋白在Y654和Y142位点磷酸化，当这两个位点被阻断时，内皮细胞高通透性得以逆转。机制上，Y654位点的磷酸化被Src失活所阻断，而Y142位点的磷酸化则被黏着斑激酶抑制剂所降低。AGEs诱导的β-连环蛋白Y654磷酸化促进了血管内皮（VE）-钙黏蛋白/β-连环蛋白的解离以及黏附连接（AJs）的损伤，而β-连环蛋白Y142磷酸化则有利于β-连环蛋白与α-连环蛋白的解离。进一步研究表明，AGEs介导的β-连环蛋白核转位需要β-连环蛋白Y142磷酸化，而这种定位于细胞核的β-连环蛋白随后激活了TCF/LEF通路。该通路促进Wnt靶基因ADAM10（一种去整合素和金属蛋白酶10）的转录，ADAM10介导VE-钙黏蛋白的脱落并导致AJs进一步受损。总之，我们的研究揭示了β-连环蛋白Y654和Y142磷酸化在AGEs介导的内皮细胞高通透性中的作用，其通过VE-钙黏蛋白/β-连环蛋白/α-连环蛋白的解离以及ADAM10的上调来实现，从而加深了我们对AGEs诱导微血管高通透性潜在机制的理解。
