iRhom2 is involved in lipopolysaccharide-induced cardiac injury in vivo and in vitro through regulating inflammation response.

Heart is a complex assembly of many cell types constituting of myocardium, endocardium and epicardium that intensively communicate to each other in order to maintain the proper cardiac function. Previous research has demonstrated that lipopolysaccharide (LPS) can induce myocardial dysfunction. iRhom2 is encoded by the gene Rhbdf2, regulating inflammation via tumor necrosis factor-α (TNF-α). In this study, we attempted to investigate the role of iRhom2 in LPS-induced cardiac injury and clarify the potential mechanism. We found that in vivo cardiac histopathological changes were induced after LPS challenge, accompanied with increase of TNF-α, interleukin-1β (IL-1β), interleukin-18 (IL-18) and interleukin-6 (IL-6) in serum and in heart tissue samples, which was dependent on TLR-4/NF-κB activation. Of note, we found that iRhom2 was a positive regulator for LPS-induced inflammation. LPS treatment markedly up-regulated iRhom2 and its down-streaming signal of IGS56. iRhom2 silence significantly suppress pro-inflammatory cytokines releases, and inactivated Toll-like receptor-4/Nuclear Factor kappa-B (TLR-4/NF-κB) signaling pathway in cells after LPS administration, suggesting its possible relationship with heart injury via TLR-4/NF-κB. It is concluded that iRhom2 may be a promising therapeutic target for LPS-induced cardiac injury by regulating inflammatory response.