Sirtuin 4 Knockout Aggravates Sepsis‐Induced Acute Liver Injury by Enhancing Mitochondrial Fission and Mitophagy in Hepatocytes

Background: Sepsis leads to multiorgan damage, with the liver being the main target. Sirtuin 4 (Sirt4) plays a regulatory role in mitochondrial function and metabolism, but its mechanism in liver injury caused by sepsis remains unclear. Methods: The mouse model of liver injury caused by sepsis was established by cecal ligation and puncture (CLP) surgery. The degree of liver injury in wild-type (WT) and Sirt4 gene total knockout (Sirt4-KO) mice was compared by serum AST, alanine aminotransferase (ALT), and histological analysis. The expression of mitophagy and mitochondrial dynamic indicators was detected by biochemical experiments. Results: Liver injury in Sirt4-KO mice was more severe than that in WT mice after CLP, manifested as significant upregulation of mitophagy and mitochondrial dynamics imbalance. Mechanistically, Sirt4 deficiency increases mitochondrial fission and mitophagy, thereby leading to cellular damage. Conclusions: Sirt4 knockout (KO) aggravates liver injury in sepsis through increasing mitochondrial fission and mitophagy, which indicates a promising direction for future clinical treatment.