A novel multifunctional peptide oligomer of bacitracin with possible bioindustrial and therapeutic applications from a Korean food-source Bacillus strain

Investigating the effects of a multifunctional microbial peptide possessing strong anti-inflammatory activity against pathogenic bacteria. The antimicrobial activity of the purified peptide (CSP32) against various multidrug-resistant as well as anaerobic pathogens was determined. Anti-inflammatory activity was determined by an enzyme-linked immunosorbent assay, western blotting, and RT-PCR in RAW 264.7 macrophages. Molecular weight and structural elucidation were performed by several analytical methods such as mass spectrometry and chemoinformatic analysis. CSP32, purified from newly isolated Bacillus sp. CS32, was active against methicillin-resistant Staphylococcus aureus, vancomycin-resistant S. aureus, vancomycin-resistant enterococci, and anaerobic pathogens Propionibacterium acne and Clostridium difficile. Furthermore, CSP32 showed strong inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production and nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) expression in RAW 264.7 macrophages. At concentrations of 10, 50, and 100 μg/mL, CSP32 treatment attenuated LPS-induced expression of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) as well as other proinflammatory mediators such as tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and IL-1β. CSP32 potently inhibited translocation of NF-κB into the nucleus by suppressing degradation of IκB kinase (IκBα) and its phosphorylation, thereby causing NF-κB to remain inactive. CSP32 may be the first oligomer of bacitracin with anti-inflammatory properties. CONCLUSION: CSP32 has stable characteristics and may find bio-industrial and therapeutic applications.