Yuliang Huang

Amelioration of high fat diet induced liver lipogenesis and hepatic steatosis by interleukin-22

BACKGROUND & AIMS Interleukin-22 (IL-22) is a Th17-related cytokine within the IL-10 family and plays an important role in host defense and inflammatory responses in orchestration with other Th17 cytokines. IL-22 exerts its functions in non-immune cells as its functional receptor IL-22R1 is restricted in peripheral tissues but not in immune cells. It was recently found that IL-22 serves as a protective molecule to counteract the destructive nature of the T cell-mediated immune response to liver damage. However, it is currently unknown whether IL-22 has an effect on lipid metabolism in the liver. METHODS In this study, we demonstrate that IL-22 alleviates hepatic steatosis induced by high fat diet (HFD). RESULTS Administration of recombinant murine IL-22 (rmIL-22) was able to stimulate STAT3 phosphorylation in HepG2 cells and mouse liver. The activation of STAT3 by rmIL-22 was reduced by the over-expression of a dominant negative IL-22R1. Within hours after rmIL-22 treatment, the expression of lipogenesis-related genes including critical transcription factors and enzymes for lipid synthesis in the liver was significantly down-regulated. The levels of triglyceride and cholesterol in the liver were significantly reduced by long-term treatment of rmIL-22 in C57BL/6 and ob/ob mice fed with HFD. The HFD-induced increases of ALT and AST in ob/ob mice were ameliorated by rmIL-22 treatment. In addition, the expression of fatty acid synthase and TNF-alpha in the liver was decreased by long-term rmIL-22 administration. CONCLUSIONS Collectively, these data indicate that IL-22, in addition to its known functions in host defense and inflammation, has a protective role in HFD-induced hepatic steatosis via its regulation on lipid metabolism in the liver.

Safety, pharmacokinetics, and biomarkers of F-652, a recombinant human interleukin-22 dimer, in healthy subjects

F-652 is a recombinant fusion protein consisting of two human interleukin-22 (IL-22) molecules linked to an immunoglobulin constant region (IgG2-Fc). IL-22 plays critical roles in promoting tissue repair and suppressing bacterial infection. The safety, pharmacokinetics (PK), tolerability, and biomarkers of F-652 were evaluated following a single dose in healthy male volunteers in a randomized, double-blind, placebo-controlled study. Following single-dose subcutaneous (SC) injection of F-652 at 2.0 µg/kg into healthy subjects, six out of six subjects experienced delayed injection site reactions, which presented as erythematous and/or discoid eczematous lesions 10 to 17 days post-dosing. F-652 was then administered to the healthy subjects via an intravenous (IV) infusion at 2.0, 10, 30, and 45 µg/kg. No severe adverse event (SAE) was observed during the study. Among the IV-dosed cohorts, eye and skin treatment emergent adverse events (TEAEs) were observed in the 30 and 45 µg/kg cohorts. F-652 IV dosing resulted in linear increases in Cmax and AUC(0–t), and the T1/2 ranged from 39.4 to 206 h in the cohorts. An IV injection of F-652 induced dose-dependent increases in serum marker serum amyloid A, C-reactive protein, and FIB, and decreased serum triglycerides. The serum levels of 36 common pro-inflammatory cytokines/chemokines were not altered by the treatment of F-652 at 45 μg/kg. In conclusion, IV administration of F-652 to healthy male volunteers is safe and well-tolerated and demonstrates favorable PK and pharmacodynamic properties. These results warrant further clinical development of F-652 to treat inflammatory diseases.