Gu Xianliang, Ge Lingling, Ren Bangqi, Fang Yajie, Li Yijian, Wang Yi, Xu Haiwei
Southwest Hospital/Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, China.
Key Lab of Visual Damage & Regeneration and Restoration of Chongqing, Chongqing, China.
Front Cell Dev Biol. 2021 Dec 14;9:738341. doi: 10.3389/fcell.2021.738341. eCollection 2021.
Remodeling of extracellular matrix (ECM) components of endothelial cells is the main cause of retinal vascular basement membrane (BM) thickening, which leads to the initiation and perpetuation of microvasculopathy of diabetic retinopathy (DR). Excessive amounts of glucocorticoids (GCs) are related to the presence and severity of DR, however transcriptional effects of GCs on the biology of human retinal capillary endothelial cells (HRCECs) and its impacts on DR are still unclear. Here, we showed that GC (hydrocortisone) treatment induced ECM component [fibronectin (FN) and type IV collagen (Col IV)] expression and morphological changes in HRCECs via the glucocorticoid receptor (GR), which depended on the nuclear translocation of YAP coactivator. Mechanistically, GCs induced stress fiber formation in HRCECs, while blocking stress fiber formation inhibited GC-induced YAP nuclear translocation. Overexpression of FN, but not Col IV, activated YAP through the promotion of stress fiber formation via ECM-integrin signaling. Thus, a feedforward loop is established to sustain YAP activity. Using mRNA sequencing of HRCECs with overexpressed YAP or GC treatment, we found a similarity in Gene Ontology (GO) terms, differentially expressed genes (DEGs) and transcription factors (TFs) between the two RNA-seq datasets. , YAP was activated in retina vascular ECs of STZ-induced diabetic mice, and TF prediction analysis of published RNA-seq data of dermal vascular ECs from T2DM patients showed that GR and TEAD (the main transcription factor for YAP) were enriched. Together, GCs activate YAP and promote ECM component (FN and Col IV) remodeling in retinal capillary endothelial cells, and the underlying regulatory mechanism may provide new insights into the vascular BM thickening of the retina in the early pathogenesis of DR.
内皮细胞细胞外基质（ECM）成分的重塑是视网膜血管基底膜（BM）增厚的主要原因，这会导致糖尿病视网膜病变（DR）微血管病变的起始和持续发展。过量的糖皮质激素（GCs）与DR的发生和严重程度有关，然而GCs对人视网膜毛细血管内皮细胞（HRCECs）生物学的转录作用及其对DR的影响仍不清楚。在此，我们表明GC（氢化可的松）处理通过糖皮质激素受体（GR）诱导HRCECs中ECM成分[纤连蛋白（FN）和IV型胶原（Col IV）]的表达及形态变化，这依赖于YAP共激活因子的核转位。机制上，GCs诱导HRCECs中应力纤维形成，而阻断应力纤维形成可抑制GC诱导的YAP核转位。FN的过表达而非Col IV的过表达通过ECM-整合素信号促进应力纤维形成从而激活YAP。因此，建立了一个前馈环以维持YAP活性。通过对YAP过表达或GC处理的HRCECs进行mRNA测序，我们发现两个RNA测序数据集之间在基因本体（GO）术语、差异表达基因（DEGs）和转录因子（TFs）方面具有相似性。在链脲佐菌素诱导的糖尿病小鼠的视网膜血管内皮细胞中YAP被激活，对2型糖尿病患者皮肤血管内皮细胞已发表的RNA测序数据进行TF预测分析表明GR和TEAD（YAP的主要转录因子）富集。总之，GCs激活YAP并促进视网膜毛细血管内皮细胞中ECM成分（FN和Col IV）的重塑，其潜在的调控机制可能为DR早期发病机制中视网膜血管BM增厚提供新的见解。
