Background & aims: Non-alcoholic fatty liver disease (NAFLD) has emerged as a major liver disease increasingly in association with non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma (HCC). However, there are currently no approved therapies for treating NAFLD and NASH. Fibroblast growth factor 4 (FGF4) has recently been shown as a promising drug candidate for several metabolic diseases.
Methods: Mice fed a high-fat diet with high fructose/glucose drinking water (HF/HFG, Western-like diet) for 21 weeks were intraperitoneally injected with non-mitogenic recombinant FGF4△NT (rFGF4△NT, 1.0 mg/kg body weight) every other day for 8 weeks. Primary mouse hepatocytes cultured in medium containing high glucose/palmitic acid (HG/PA) or TNFα/cyclohexane (TNFα/CHX) were treated with 1.0 μg/ml rFGF4△NT. Changes in parameters for histopathology, lipid metabolism, inflammation, hepatocellular apoptosis and fibrosis were determined. The Caspase6 activity and AMPK pathway were assessed.
Results: Administration of rFGF4△NT significantly attenuated the Western-like diet-induced hepatic steatosis, inflammation, liver injury and fibrosis in mice. rFGF4△NT treatment reduced fatty acid-induced lipid accumulation and lipotoxicity-induced hepatocyte apoptosis, which were associated with inhibition of Caspase6 cleavage and activation. Inhibition of AMP-activated protein kinase (AMPK) by Compound C or deficiency of Ampk abrogated rFGF4△NT-induced hepatoprotection in primary hepatocytes and in mice with NASH.
Conclusion: rFGF4△NT exerts significant protective effects on NASH via an AMPK-dependent signaling pathway. Our study indicates that FGF4 analogs may have therapeutic potential for the Western-like diet induced NASH.
Keywords: AMP-activated protein kinase; Apoptosis; Fibrosis; Inflammation; NASH; Non-mitogenic fibroblast growth factor 4.
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