Anti-fibrosis application of overexpression and recombinant human CYGB in multiple models of advanced fibrosis

AIM: We report the anti-fibrotic properties of cytoglobin (CYGB), a respiratory protein that is expressed in hepatic stellate cells (HSCs). METHODS: Cygb deficiency or specific overexpression in stellate cells with mCherry reporter (TG) mice underwent bile duct ligation (BDL) or choline-deficient L-amino acid-defined (CDAA) diet. Recombinant human CYGB (rhCYGB) was produced, and examined its bio-distribution and function in HSCs or in mice treated with TAA or DDC inducing advanced liver fibrosis. Humanized liver chimeric PXB mice were used for safety assay. RNA-Seq and pathway analysis in both rhCYGB-treated HSCs and liver tissues were performed. RESULTS: Cygb loss significantly exacerbated liver damage, fibrosis, and reactive oxygen species (ROS) formation in both BDL and CDAA models, whereas all these manifestations were attenuated in TG mice. In cultured HSCs, rhCYGB was endocytosed and accumulated in endosomes via clathrin-mediated pathway, in which clathrin inhibitor attenuated its incorporation. rhCYGB significantly impeded ROS formation and fibrogenesis spontaneously or in the presence of ROS inducers or TGFβ1 challenge in HSCs. We found that rhCYGB regulates the fibrosis pathway in HSCs via both ROS scavenging and interferon-β secretion by activating TAK-1, and p-STAT-1. Momelotinib nullified the effect of rhCYGB. Intravenously injected rhCYGB reached the HSCs and strongly suppressed liver injuries and fibrosis in TAA or DDC administrated mice. CONCLUSION: rhCYGB could have anti-fibrotic applications.