The suppression of ox-LDL-induced inflammatory cytokine release and apoptosis of HCAECs by long non-coding RNA-MALAT1...

Atherosclerosis is a chronic inflammatory disease. Accumulating evidence suggests that long non-coding RNAs (lncRNAs) and microRNAs have emerged as critical regulators of atherosclerosis; however, whether they have crosstalk on this issue remains elusive. Here, we investigated the potential associations between lncRNA-MALAT1 and miR-155 on the regulation of atherosclerosis.

Quantitative real-time PCR was employed to assess the expression of MALAT1, IL-6 and IL-8. ELISA was performed to measure the secretion of IL-6 and IL-8. MTT assay was used to determine the proliferation of Human Coronary Artery Endothelial Cells (HCAECs). Flow cytometry was used to measure the cell apoptosis. Western blot was used to assess the expression of apoptosis-related proteins and the phosphorylation of STAT1 and STAT3.

We found that the pro-inflammatory cytokine release and the apoptosis of HCAECs were elevated upon ox-LDL treatment, while MALAT1 expression was also up regulated. Knocking down of MALAT1 boosted ox-LDL-induced cytokine release and apoptosis of HCAECs. The binding site of miR-155 in MALAT1 sequence was confirmed by dual luciferase assay. Furthermore, miR-155 inhibition significantly repressed ox-LDL mediated inflammation and apoptosis of HCAECs via SOCS1. At last, we found that MALAT1 could suppress the inflammatory cytokine release and cell apoptosis via sponging miR-155 to increase SOCS1 level, which in turn restrained JAK-STAT pathway.

In summary, this study revealed the mechanisms by which MALAT1 worked as a putative atherosclerosis suppressor via miR-155 and SOCS1. Therefore, modulation of MALAT1/miR-155/SOCS1 axis might alleviate the inflammation persisted in atherosclerosis.