Nomilin attenuates lipopolysaccharide-induced inflammatory response by binding with myeloid differentiation protein-2.

Abstract

Nomilin shows anti-inflammatory activity by inhibiting the activation of the Toll-like receptor 4 (TLR 4)/NF-κB pathway. However, the key target of the anti-inflammatory activity of nomilin has not been elaborated and needs further exploration. This study aimed to assess the drug potential of nomilin and its ability to target myeloid differentiation protein 2 (MD-2) as a mechanism underlying the anti-inflammatory activity of nomilin on the lipopolysaccharide (LPS)-TLR4/MD-2-NF-κB signaling pathways. The methods of ForteBio and molecular docking were used to investigate the internation between MD-2 and nomilin. 3-(4,5)-Dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide experiment was performed to test the effect of nomilin on cell viability. Enzyme-linked immunosorbent assay, real-time polymerase chain reaction, and Western blot experiments were carried out to assess the anti-inflammatory activity and possible mechanism of nomilin in vitro. The results indicated that nomilin exhibited binding affinity with MD-2. Nomilin significantly reduced the release and expression of NO, IL-6, TNF-α, and IL-1β induced by LPS in vitro. It inhibited the expression of LPS-TLR4/MD-2-NF-κB signaling pathway proteins, such as TLR4, Myd88, P65, P-P65, and iNOS. Our results suggested that nomilin had therapeutic potential and was bound to MD-2. Nomilin exhibited anti-inflammatory activity by binding to the key protein MD-2 and inhibiting the LPS-TLR4/MD-2-NF-κB signaling pathway.