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Lactobacillus mucosae extracellular vesicles improve metabolic dysfunction-associated fatty liver disease by
Kaige Zhang1,2,3, Yuyu Zeng4, Zhaohui Liao1
1Department of Gastroenterology, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, 330000, Jiangxi, China.
Background And Objective:
Metabolic dysfunction-associated fatty liver disease (MAFLD) is the most prevalent chronic liver disease worldwide but lacks effective therapies. Gut microbiota play a key role in MAFLD via the gut-liver axis, yet targeted interventions remain unclear. This study investigates the therapeutic effects and mechanisms of Lactobacillus mucosae (L. mucosae) and its extracellular vesicles (EVs) in MAFLD.
Methods:
At the clinical level, 16S rRNA sequencing was performed to analyze differences in gut microbiota composition between MAFLD patients and healthy controls, followed by the identification of a core probiotic strain, L. mucosae, using culture-based approaches. A high-fat diet-induced MAFLD mouse model was subsequently established to evaluate the therapeutic effects of L. mucosae, while free fatty acid-induced hepatocyte models were used to identify L. mucosae-EVs as the key active component. Mechanistic investigations and validation were further conducted in vivo and in vitro using RNA sequencing, qPCR, Western blot analyses, DIA-based EV proteomics, and Proteinase K-mediated EV protein functional assays.
Results:
MAFLD patients showed reduced intestinal Lactobacillus abundance, negatively correlated with hepatic lipid parameters. L. mucosae administration alleviated steatosis, metabolic dysfunction, inflammation, and oxidative stress in mice. In vitro, L. mucosae-EVs were confirmed as the main active component, and Proteinase K-pretreated EVs showed attenuated protective effects on hepatocytes. Mechanistically, L. mucosae-EVs activated hepatic AMPK signaling via the gut-liver axis, remodeled gut microbiota, and restored intestinal barrier integrity.
Conclusion:
This study systematically demonstrates for the first time that L. mucosae-EVs ameliorate MAFLD through multiple mechanisms, including gut microbiota remodeling, intestinal barrier restoration, and activation of hepatic AMPK signaling via the gut-liver axis. Proteinase K-mediated functional assays suggest that EV-associated protein cargo contributes, at least in part, to these protective effects. These findings provide a solid experimental foundation and theoretical basis for the development of precision microbiome-based therapeutic strategies for MAFLD based on L. mucosae and its EVs.