Senescence-Related SOCS1, SOCS2, and GADD45G Identify an Immune-Associated Molecular Signature in Metabolic Dysfunction-Associated Steatotic Liver Disease

Senescence-related molecular nodes linking hepatic stress with immune dysregulation in metabolic dysfunction-associated steatotic liver disease (MASLD) remain poorly defined. This study aimed to identify and experimentally validate a senescence-related gene (SRG) signature associated with immune dysregulation in MASLD. Four transcriptomic datasets (127 controls, 127 MASLD) were integrated as the discovery cohort. Candidate SRGs were identified through differential expression analysis, weighted gene co-expression network analysis, and three machine learning algorithms. Immune infiltration was assessed using CIBERSORT, and a three-gene signature was evaluated in internal and external cohorts. Potential GADD45G-associated compounds were predicted by molecular docking. Experimental validation was performed in high-fat diet (HFD)-induced obese mice and palmitic acid (PA)-stimulated bone marrow-derived macrophages (BMDMs). Single-cell RNA sequencing analysis of GSE300744 was further performed to evaluate GADD45G distribution in hepatic cell populations. SOCS1, SOCS2, and GADD45G were identified as core SRGs. Their expression was reduced in MASLD liver tissues and correlated with histological features and immune alterations. The three-gene signature showed favorable classification performance in validation cohorts. In HFD mice, GADD45G expression was decreased at both mRNA and protein levels, with reduced immunoreactivity in F4/80-positive hepatic macrophages. Single-cell analysis further supported macrophage-associated expression of Gadd45g. In PA-stimulated BMDMs, reduced GADD45G protein expression was partially restored by camptothecin and myristicin treatment. Overall, SOCS1, SOCS2, and GADD45G represent a candidate senescence-related immune signature associated with MASLD. The macrophage-associated reduction in GADD45G and its modulation in vitro provide preliminary evidence for a potential role of GADD45G in MASLD-associated immune dysregulation.