Effect and Potential Mechanism of Inhibition of Long Non-coding RNA MALAT1 on Glycolipipotoxicity-induced Endothelial Cell Dysfunction / 中国循环杂志

ABSTRACT

Objectives:To investigate the effect of inhibition of long non-coding RNA(lnc RNA)in human metastasis associated lung adenocarcinoma transcript 1(MALAT1)on glycolipitoxicity-induced human umbilical vein endothelial cell dysfunction. Methods:Human umbilical vein endothelial cells were treated with glucose and palmitic acid in vitro to establish the glycolipitoxic endothelial cell models.Following groups were examined:control group,high-glucose and high-fat group,high-glucose and high-fat + non-targeting RAN control group,high-glucose and high-lipid+MALAT1 siRNA group,and high-glucose and high-lipid+MAPK1 siRNA group.RT-qPCR was used to detect the mRNA expression of MALAT1 and MAPK1.Western blot was used to detect the expression levels of autophagy,mitochondrial fusion division,apoptosis,and pathway-related proteins.Immunofluorescence confocal localization was used to detect the fluorescence colocalization of autophagy and lysosome-related proteins.The number of autophagolysosomes in endothelial cells was observed by transmission electron microscopy.Mitochondrial probe staining was used to detect mitochondrial morphology,immunofluorescence was used to detect intracellular reactive oxygen species(ROS)production,flow cytometry was used to detect the apoptosis of cells in each group,cell proliferation and scratch assays were used to detect the proliferation and migration ability of cells in different groups at different time points.The angiogenesis was quantified by counting the number of new blood vessels in each group. Results:Compared with the control group,the expression of lncRNA MALAT1 mRNA and the expression of phosphorylated mito-activated protein kinase 1(p-MAPK1)were upregulated(both P＜0.05)and the expression of phosphorylated mammalian target protein(p-mTOR)was downregulated in the high-glucose and high-fat group and the high-sugar and high-fat control group(all P＜0.01).Compared with the high-glucose and high-fat non-targeting RNA control group,the expressions of microtubule-associated protein 1A/1B-light chain 3(LC3)and p62 were downregulated(P＜0.01,P＜0.05),LC3 and lysosome-associated membrane protein 2(LAMP2)protein co-localized positive fluorescence particles were increased(both P＜0.01),number of lysosomes were decreased,the expression of ROS was decreased(P＜0.01),the expression level of mitochondrial fusion protein optic nerve atrophin 1(OPA1)was increased(P＜0.05),the expressions of cleaved caspase-3 and BCL-2-related X protein(BAX)were decreased and BCL-2 was increased(all P＜0.05),cell proliferation,migration,and tube-forming ability were increased(all P＜0.01),and the expression of p-MAPK1 was decreased(P＜0.05)and p-mTOR expression was increased(both P＜0.05)in the high-glucose and high-lipid+si-MALAT1 group.Compared with the high-glucose and high-fat non-targeting RNA control group,the expression of p-MAPK1 in endothelial cells was decreased and the expression of p-mTOR was increased in the high-glucose and high-lipid+si-MAPK1 group(both P＜0.01). Conclusions:Inhibition of lncRNA MALAT1 expression can reduce the level of mitophagy in glycolipidotoxic environments,reduce apoptosis of endothelial cells and improve endothelial cell function,which may be related to the regulation of MAPK1/mTOR signaling pathway.