Bifidobacterium bifidum CIP-01 attenuates metabolic dysfunction-associated steatotic liver disease induced by high-alcohol-producing Klebsiella pneumoniae.

Abstract

BACKGROUND: High-alcohol-producing Klebsiella pneumoniae (HiAlc Kpn) can cause metabolic dysfunction-associated steatotic liver disease (MASLD) through sustained alcohol overflow in the microenvironment. As a probiotic, Bifidobacterium bifidum (B. bifidum) exhibits unique anti-inflammatory properties; however, whether and how it alleviate MASLD induced by HiAlc Kpn requires further investigation. METHODS: MASLD mouse model was constructed by gavage administration with HiAlc Kpn W14 to assess the therapeutic effect of B. bifidum CIP-01 in vivo. Cell infection models, metabolomics sequencing, and in vitro antibacterial assays were integrated to systematically elucidate the mechanism by which B. bifidum CIP-01 mitigates HiAlc Kpn W14-induced cell damage. RESULTS: B. bifidum CIP-01 was able to ameliorate MASLD induced by HiAlc Kpn through a multi-target mechanism. Compared to pair-fed mice, HiAlc Kpn W14 disrupted gut barrier and promoted inflammatory cytokines release. While, supplementation with B. bifidum CIP-01 reversed these effects by a) restoring intestinal integrity via upregulating tight junction proteins (ZO-1/Occludin) and mucin protein MUC-2, reducing reactive oxidative stress (ROS) and apoptosis in colonic cells, and b) rescuing hepatic cytochrome P450 2E1 (CYP2E1)-driven oxidative injury (ROS/Caspase-3) while promoting mitochondrial β-oxidation, as well as c) directly suppressing HiAlc Kpn proliferation and biofilm formation. Metabolomics and 16S rRNA of fecal samples analyses revealed B. bifidum CIP-01-mediated metabolic regulation: depletion of toxic branched-chain amino acids (BCAAs) intermediates and restoration of energy homeostasis and antioxidant defense alongside increased short-chain fatty acids (SCFAs)-associated pathways. CONCLUSION: Our findings highlight B. bifidum CIP-01 as a novel therapeutic candidate for HiAlc Kpn-induced MASLD, operating through a triad of pathogen suppression, gut-liver axis repair, and metabolic regulation.