Sleeve Gastrectomy Alters Exosomal miR-497-5p Cargo to Ameliorate Metabolic Dysfunction-Associated Steatotic Liver by Targeting GABARAPL1

Background: Obesity is strongly associated with metabolic dysfunction and steatotic liver disease (MASLD). Laparoscopic sleeve gastrectomy (LSG) effectively addresses severe obesity and its metabolic complications. Recent studies suggest that exosomes and their MicroRNA (miRNA) content mediate systemic metabolic improvements following bariatric surgery.

Objective: This study aims to characterize plasma exosomal miRNAs before and after LSG, identify functional candidates linked to MASLD remission, and validate underlying mechanisms in vitro.

Methods: Plasma exosomes from control subjects, as well as pre- and post-LSG patients, were isolated via ultracentrifugation, characterized, and subjected to high-throughput miRNA Sequencing. Differential expression analysis, weighted gene co-expression network analysis, and random forest modeling were used to identify key miRNAs. Predicted targets, based on multi-database consensus, were integrated with paired liver transcriptomes from GEO (GSE106737, GSE83452). miRNA-target interactions were confirmed through dual-luciferase assays. In a free fatty acid-induced HepG2 MASLD model, miRNA mimics/inhibitors were employed to evaluate lipid accumulation (Oil Red O, intracellular triacylglycerol/total Cholesterol) and target expression (qRT-PCR, Western blot).

Results: LSG significantly altered circulating exosomal miRNA profiles. Six key miRNAs were identified, with miR-497-5p being the most prominent. Integrative analysis revealed GABARAPL1 as a direct target of miR-497-5p, and its upregulation in post-LSG liver tissues. Luciferase assays confirmed miR-497-5p binding to the GABARAPL1 3'UTR. In HepG2 cells, inhibition of miR-497-5p reduced lipid droplet formation and intracellular triacylglycerol/total Cholesterol levels, while overexpression exacerbated steatosis. Inhibition also led to increased GABARAPL1 mRNA and protein levels.

Conclusion: LSG induces significant remodeling of the circulating exosomal miRNA profile. Specifically, the downregulation of exosomal miR-497-5p post-LSG appears to alleviate hepatic lipid accumulation by derepressing its target, GABARAPL1, a key regulator of lipophagy. miR-497-5p is thus a potential biomarker and therapeutic target.