Microbiota-host genetic interactions modulate MASLD risk in PNPLA3 I148M carriers via ceramides and are reversible by targeted microbial interventions

Abstract

Background The factors that determine when genetic susceptibility to metabolic dysfunction-associated steatotic liver disease (MASLD) progresses to clinically significant liver injury remain incompletely understood. Objective We investigated whether disruption of the intestinal host-microbiota interface acts as a contextual modifier that amplifies PNPLA3 I148M -associated hepatic injury. Design We used a dual-hit mouse model combining hepatic Pnpla3 I148M -expression with Nlrp6 -deficiency, a model of impaired intestinal mucosal homeostasis, under western-diet conditions. Multi-omics profiling, including metagenomics, metabolomics and transcriptomics, was integrated with analyses in human cohorts (Lifelines, Charité MASLD, Human Phenotype Project). Microbiota-dependent effects were examined using faecal microbiota transplantation (FMT), antibiotic-mediated depletion and targeted intervention with Akkermansia muciniphila or its membrane protein Amuc_1100. Results In mice, the combination of Pnpla3 I148M expression and impaired intestinal sensing synergistically exacerbated gut-barrier dysfunction and bacterial encroachment, accompanied by increased portal levels of microbiota-associated metabolites, including long-chain ceramides (Cer(d18:1/16:0), Cer(d18:1/18:0)) and bile acids. These changes were associated with hepatic mitochondrial stress and inflammatory responses. Human carriers with advanced MASLD displayed microbial and metabolic signatures consistent with increased gut-derived metabolic signalling. Restoration of eubiotic microbiota via FMT or Amuc_1100 treatment improved intestinal barrier integrity and attenuated hepatic lipid accumulation in experimental models. Conclusion These findings suggest that gut-derived signals resulting from a disrupted intestinal barrier may act as modifiers of PNPLA3 I148M -clinical penetrance by amplifying downstream metabolic and inflammatory responses. By identifying these pathways linking environmental context to genetic susceptibility, this study highlights the host-microbiota interface as a potential target for strategies aimed at limiting MASLD progression in genetically at-risk individuals.