H-RN, a novel antiangiogenic peptide derived from hepatocyte growth factor inhibits inflammation in vitro and in vivo through PI3K/AKT/IKK/NF-κB signal pathway.

H-RN, a novel antiangiogenic peptide derived from the kringle 1 domain of hepatocyte growth factor (HGF), consists of the sequence RNPRGEEGGPW (molecular weight: 1254.34Da). Emerging evidence indicates that HGF and the kringle domain exhibit anti-inflammatory effects in inflammatory diseases. In the present study, we assessed the anti-inflammatory effect of H-RN in models of experimental ocular inflammation, including endotoxin-induced uveitis (EIU) and experimental autoimmune uveitis (EAU). The results demonstrated that intravitreal treatment of H-RN concentration-dependently suppressed clinical manifestation, inhibited ocular inflammatory cytokine production and improved histopathologic scores. Moreover, H-RN attenuated the LPS-induced mRNA and protein expression of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in RAW 264.7 cells and inhibited cell chemotactic migration toward LPS. We also demonstrated that H-RN suppressed TNF-α-induced adhesion molecule expression in HUVECs, including ICAM-1, VCAM-1 and E-selectin, which contributed to its suppressive effect on adherence of U937 cells to endothelial cells. We also demonstrated the possible anti-inflammation mechanism of H-RN. Western blot and immunofluorescence staining analyses revealed that H-RN significantly suppressed LPS-induced phosphorylation of nuclear factor (NF)-κB-p65 at Ser276. Based on examination of upstream pathways, we found that H-RN inhibited PI3K-p85 and AKT(Ser473) phosphorylation, which may result in the attenuation of LPS-induced IKK complex activation and IκB degradation. Thus, our studies suggest that the 11-amino-acid peptide H-RN exhibits anti-inflammatory effects in vitro and in vivo and may represent a promising candidate for ocular inflammatory diseases.