Knockdown of MALAT1 attenuates high-glucose-induced angiogenesis and inflammation via endoplasmic reticulum stress in human retinal vascular endothelial cells.

Diabetic retinopathy (DR) is one of the most severe complications of diabetes mellitus, and retinal endoplasmic reticulum stress (ERS) plays an important role in the pathogenesis of DR. However, the exact mechanisms by which ERS mediates DR remain unclear. In this study, human retinal vascular endothelial cells (RVECs) were cultured in high-glucose (HG) medium to mimic the environment of DR. The expression of long non-coding RNA (lncRNA)-metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was determined by quantitative real time PCR. ERS markers (glucose-regulated protein 78 [GRP78] and C/EBP homologous protein [CHOP]) were measured by immunofluorescence and western blotting. Cell viability was analyzed by the CCK-8 assay. The angiogenesis of RVECs was evaluated by tube formation assays. The levels of pro-inflammation cytokines TNF-α and IL-6 in RVECs were determined by ELISA assays. We found that exposure to HG levels upregulated MALAT1 and GRP78 expression in RVECs. While, GRP78 overexpression strengthened CHOP expression, cell proliferation suppression, capillary morphogenesis and inflammation in HG-treated RVECs. Importantly, knockdown of MALAT1 reversed HG-induced cell proliferation suppression, inhibited capillary morphogenesis, and inflammation in RVECs, and those effects were reversed by GRP78 overexpression. These results suggest that MALAT1 promotes HG-induced angiogenesis and inflammation in RVECs by upregulating ER stress, and might be target for treating DR.

MiR-126 enhances VEGF expression in induced pluripotent stem cell-derived retinal neural stem cells by targeting spred-1.

Pathological retinal neovascularization (RNV) is a leading cause of vision loss in several ocular diseases; however, the underlying molecular mechanisms involved in the development of RNV remain unclear. It has been shown that microRNAs contribute to the process of angiogenesis, which has received greater attention by investigators who study the progression of RNV. In the present study, we investigated the function of miR-126 expression in retinal neural stem cells derived from induced pluripotent stem cell (IPSs) obtained from patients with RNV. During the induction process, the levels of both miR126 and vascular endothelial growth factor C (VEGF-C) gradually decreased, while the levels of spred-1 significantly increased. The existence of conserved miR-126-binding sites in spred-1 mRNA was predicted by computational algorithms, and verified by the luciferase reporter assay. The use of miR-126 mimics revealed dramatically reduced levels of spred-1, and increased levels of VEGF. When using shRNA to target spred-1, the resultant decreased levels of spred-1 were associated with significantly enhanced levels of VEGF expression. Our results demonstrate that miR-126 promotes VEGF expression in IPS cells by suppressing spred-1 expression, which contributes to angiogenesis during the progression of RNV. These findings suggest that miR-126 and spred-1 might serve as novel molecular targets for treating RNV-related ocular diseases.