Abstract

Fine particulate matter (PM 2.5 ) exposure can cause the injury of vascular endothelial cells by inflammatory response. CD40 works in inflammation of endothelial cells and it may be regulated by the miRNAs. This study aimed to clarify the role and mechanism of CD40 and miR-145-5p in PM 2.5 -induced injury of human umbilical vein endothelial cells (HUVECs). HUVECs were treated with different concentrations of PM 2.5 exposure (0, 100, 200, 400 μg/mL) for 24 h. The si-RNA was used for CD40 gene silencing (0, 200 μg/mL PM 2.5 , siRNA-CD40 and siRNA-CD40 + 200 μg/mL PM 2.5 ). Mimics was used for overexpression of miR-145-5p (0, 200 μg/mL PM 2.5 , mimics and mimics+200 μg/mL PM 2.5 ). The cell viability of HUVECs was detected with Cell Counting Kit8 (CCK8) kit. The level of cell apoptosis was detected by flow cytometry. The inflammation-related factor including interleukin-1β (IL-1β), interleukin-18 (IL-18), tumor necrosis factor α (TNF-α) and C1q complement/tumor necrosis factor (TNF)-associated proteins9 (CTRP9) were tested with enzyme-linked immunosorbent assay (ELISA) kits. The mRNA and protein expression levels of CD40 , CD40L , caspase1 , NLRP3 (Nod-like receptor family pyrin domain-containing 3 ) and IKKB were detected with quantitative real-time PCR (qRT-PCR), Western blot and Immunofluorescence. Compared with the control group, the cell viability of HUVECs exposed to PM 2.5 was significantly decreased ( p < 0.05); the levels of IL-Iβ and TNF-α were significantly increased, while the level of CTRP9 was significantly decreased ( p < 0.05). The proportion of apoptotic cells was increased after being treated with PM 2.5 ( p < 0.05). Besides, the mRNA and protein levels of CD40, CD40L, IKKB, NLRP3 and caspase1 were increased comparing with the control group ( p < 0.05). After CD40 silencing, the condition of inflammation and apoptosis in HUVECs exposed to