Integrated liver transcriptomic data reveal differences in aging-associated regulation between metabolic dysfunction-associated steatotic liver disease and normal liver aging.

Abstract

Age-related molecular trajectories of metabolic dysfunction-associated steatotic liver disease (MASLD) remain insufficiently characterized, limiting age-stratified risk assessment and intervention. To test whether MASLD-related molecular changes with age merely reflect accelerated physiological aging or represent a disease-specific divergence. We utilized public transcriptomic data from normal liver and MASLD samples to identify differential transcriptomic signals. We employed Spearman correlation analysis and generalized additive models (GAM) for nonlinear age-related trajectory modeling, and functional enrichment analysis for signaling pathway characterization. We integrated 1,354 public liver transcriptome samples from GEO and GTEx databases to construct a cross-age cohort. Differential expression and age-correlation analyses showed minimal overlap (only 22 genes) between age-associated genes in MASLD and controls, with some genes displaying opposite age-related trends. GAM identified four major expression patterns in MASLD-stable, early-life change, late-life acceleration, and mid-life fluctuation-with trajectory inflection time points around ages ~35 and ~75. Functional enrichment indicated that control age-associated genes mainly involved classical cell cycle processes, whereas MASLD changes were enriched for protein deubiquitination, proteostasis imbalance, and p53-related stress and apoptotic signaling. Many MASLD age-associated genes were also associated with fibrosis stage or NAS, largely in concordant directions. MASLD exhibits disease-specific age-related transcriptional remodeling characterized by dysregulation of proteostasis and deubiquitination pathways, activation of cellular stress-response programs, and enrichment of p53-associated apoptotic signaling, rather than a simple acceleration of physiological aging.