F13A1-Mediated Macrophage Activation Promotes MASH Progression via the PKM2/HIF1A Pathway.

Macrophages are central mediators of hepatic inflammation and fibrosis in metabolic-associated steatohepatitis (MASH), yet the mechanisms driving their activation remain unclear. Integration of four human single-nucleus transcriptomic datasets identified Coagulation Factor XIII-A (F13A1)-positive macrophages as the predominant subset in MASH livers, a finding validated in patient samples and murine models. Lipid-stressed hepatocytes induce F13A1 expression through a sphingosine-1-phosphate (S1P)-dependent mechanism. Silencing F13A1 suppressed the pro-inflammatory phenotype and alleviated hepatic injury in vivo. Mechanistically, F13A1 directly interacted with pyruvate kinase M2 (PKM2), promoting its dimerization, a process enhanced by intracellular calcium levels. Dimerized PKM2 translocated into the nucleus and upregulates interleukin-1 beta (IL1B) expression via the PKM2/HIF1A (Hypoxia-inducible factor 1-alpha) axis. In addition, F13A1 enhanced the Warburg effect in macrophages through PKM2-mediated metabolic reprogramming. Pharmacologic activation of PKM2 with DASA-58 abrogated F13A1-driven inflammation, and PEG-PLA micelle-mediated delivery of DASA-58 ameliorated hepatic inflammation in vivo. These findings establish F13A1 as a critical driver of macrophage-mediated inflammation in MASH and highlight the F13A1/PKM2/HIF1A pathway as a promising therapeutic target.