MiR-505 as an anti-inflammatory regulator suppresses HMGB1/NF-κB pathway in lipopolysaccharide-mediated endometritis by targeting HMGB1.

Endometritis is characterized by severe inflammation and tissue damage. It is a common clinical disease that causes infertility due to infectious diseases of the reproductive system. MicroRNAs (miRNAs) are the current focus of research on the regulation of the inflammatory process and play a vital role in various inflammatory diseases. The highly conserved miR-505 regulates the mechanism of lipopolysaccharide (LPS) induced endometritis, but the extent to which pro-inflammatory genes are activated remains unclear. The results of this study showed that the expression of miR-505 was significantly down-regulated in mouse endometritis tissue and LPS-stimulated BEND cells. The study also showed that overexpression of miR-505 significantly suppressed the production of the pro-inflammatory cytokines IL-1β, IL-6 and TNF-α, and this effect was reversed by inhibiting the expression of miR-505. Moreover, miR-505 inhibited the expression of HMGB1 by targeting its 3'-UTR, thereby inhibiting the activation of HMGB1/NF-κB signalling. Taken together, the results of this study further confirmed that miR-505, as an anti-inflammatory agent, regulates the activation of the HMGB1/NF-κB signalling pathway through negative feedback.