Fine
particulate matter (PM2.5) 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 PM2.5-induced injury of human umbilical vein endothelial cells (HUVECs). HUVECs were treated with different concentrations of PM2.5 exposure (0, 100, 200, 400 μg/mL) for 24 h. The si-
RNA was used for CD40 gene silencing (0, 200 μg/mL PM2.5,
siRNA-CD40 and
siRNA-CD40 + 200 μg/mL PM2.5). Mimics was used for overexpression of miR-145-5p (0, 200 μg/mL PM2.5, mimics and mimics+200 μg/mL PM2.5). 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 PM2.5 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 PM2.5 (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 PM2.5 was alleviated, and the expression levels of
CD40L, IKKB, NLRP3 and caspase1 were significantly decreased (p < 0.05). Furthermore, miR-145-5p was significantly down-regulated after exposure to 200μg/mL PM2.5 (p < 0.05). After over-expression of miR-145-5p, the expression level of CD40 was decreased (p < 0.05). Taken together, PM2.5 can cause
inflammation and apoptosis of HUVECs via the activation of CD40, which can be regulated by miR-145-5p. Over-expression of miR-145-5p can down-regulate CD40, further inhibiting the
inflammation and apoptosis of HUVECs induced by PM2.5.