MicroRNA-150 affects endoplasmic reticulum stress via MALAT1-miR-150 axis-mediated NF-κB pathway in LPS-challenged HUVECs and septic mice.

Aims: Sepsis is a systemic inflammatory complication, which is the common cause of death in critical patients. This study aimed to evaluate the potential regulatory mechanisms of miR-150 in lipopolysaccharide (LPS)-challenged HUVECs and cecal ligation and puncture (CLP)-induced septic mice.

Materials And Methods: Human umbilical vein endothelial cells (HUVECs) were challenged with LPS. Pulmonary arterial endothelial cells (PAECs) were isolated from CLP-induced septic mice. The mRNA and protein levels of target molecules were detected by RT-qPCR and Western blotting. Apoptosis of HUVECs was determined by Annexin V/PI staining on a flow cytometry. The interaction between miR-150 and MALAT1 was assessed by luciferase reporter assay, RIP and RNA pull-down assay.

Key Findings: MiR-150 was downregulated in LPS-induced HUVECs. MiR-150 mimics restrained LPS-induced inflammatory response by reducing TNF-α and IL-6 levels, but increasing IL-10 level. Moreover, miR-150 mimics downregulated endoplasmic reticulum (ER) stress-related proteins, GRP78 and CHOP levels in LPS-exposed HUVECs. Additionally, LPS-induced apoptosis was suppressed by miR-150 mimics via decreasing cleaved caspase-3 and Bax levels, while enhancing Bcl-2 level. Mechanistically, MALAT1 could competitively bind to miR-150. LPS-induced apoptosis, ER stress and inflammation were promoted by MALAT1 overexpression, but reversed by siMALAT1. Furthermore, miR-150 inhibitor strengthened LPS-induced apoptosis, ER stress and inflammation, which could be attenuated by siMALAT1 via regulating NF-κB pathway. Finally, agomiR-150 repressed ER stress and inflammatory response in PAECs isolated from septic mice via decreasing MALAT1 level.

Significance: Our findings suggest that miR-150 affects sepsis-induced endothelial injury by regulating ER stress and inflammation via MALAT1-mediated NF-κB pathway.