Clostridium butyricum-derived antimicrobial peptides remodel SCFA-producing gut symbionts to alleviate inflammation and enhance gut barrier integrity through microbial crosstalk

Inflammatory bowel disease (IBD) is characterized by gut microbiota dysregulation and impaired intestinal barrier function. As a potential strategy to restore gut homeostasis, we investigated the potential of antimicrobial peptides derived from Clostridium butyricum (designated CBP) to modulate gut homeostasis and attenuate intestinal inflammation. Our initial characterization identified CBP as a 0.5-3 kDa fraction from C. butyricum fermentation broth, exhibiting potent direct antimicrobial activity against pathogenic strains including Escherichia coli, Salmonella enterica., and Staphylococcus aureus. Further genome and peptidome analysis revealed that CBP comprises novel antimicrobial peptides. In a murine model of LPS-induced intestinal injury, CBP preserved intestinal architecture, restored tight junctions, maintained goblet cells, and attenuated proinflammatory cytokines. These protective effects stemmed from selective gut microbiota modulation, with distinct effects under physiological versus inflammatory conditions. Physiologically, CBP increased beneficial genera and short-chain fatty acids (like acetic, propanoic and butyric acid) while decreasing Allobaculum. During inflammation, CBP restored the LPS-disrupted Bacillota/Bacteroidota ratio by suppressing pathobionts like Bacteroides and enriching barrier protective genera. These microbial shifts were associated with improved barrier function and suppressed pro-inflammatory cytokines. The unique advantages of CBP over its probiotic counterpart, C. butyricum, explain its superior efficacy in attenuating intestinal inflammation, positioning it as a promising postbiotic candidate. Amid the escalating global threat of antimicrobial resistance, our findings position CBP as a promising, targeted alternative to conventional antibiotics for treating human gastrointestinal disorders.