Dual-Specificity Phosphatase 26 Protects Against Nonalcoholic Fatty Liver Disease in Mice Through Transforming Growth Factor Beta-Activated Kinase 1 Suppression

Nonalcoholic fatty liver disease (NAFLD), which has a wide global distribution, includes different stages ranging from simple steatosis to nonalcoholic steatohepatitis, advanced fibrosis, and liver cirrhosis according to the degree of severity. Chronic low-grade inflammation, insulin resistance, and lipid accumulation are the leading causes of NAFLD. To date, no effective medicine for NAFLD has been approved by governmental agencies. Our study demonstrated that the expression of dual-specificity phosphatase 26 (Dusp26), a member of the Dusp protein family, was decreased in the liver tissue of mice with hepatic steatosis and genetically obese (ob/ob) mice. In our study, hepatic steatosis, inflammatory responses, and insulin resistance were exacerbated in liver-specific Dusp26-knockout (KO) mice but ameliorated in liver-specific Dusp26-transgenic mice induced by a high-fat diet. In addition, the degree of liver fibrosis was aggravated in high-fat high-cholesterol diet-induced Dusp26-KO mice. We further found that the binding of Dusp26 to transforming growth factor beta-activated kinase 1 (TAK1) to block the phosphorylation of TAK1 regulated the TAK1-p38/c-Jun NH2-terminal kinase signaling axis to alleviate hepatic steatosis and metabolic disturbance. Conclusion: These findings suggest that Dusp26 is a good TAK1-dependent therapeutic target for NAFLD.