Weizmannia coagulans Extracellular Proteins Reduce Skin Acne by Inhibiting Pathogenic Bacteria and Regulating TLR2/TRAF6-Mediated NF-κB and MAPKs Signaling Pathways.

As a probiotic, Weizmannia coagulans (W. coagulans) is often used in food and medicine to regulate intestinal flora and exert anti-inflammatory effects. In this study, the anti-acne efficacy and mechanism of extracellular proteins (YTCY-EPs) from W. coagulans YTCY strain are analyzed. The main components of YTCY-EPs, extracted and separated from the fermentation broth, are peptides ranging from 1.51 to 11.44 kDa, accounting for about 80%. Among the peptides identified by LC/MS-MS, YTCY_A-F possess the properties of antimicrobial peptides, while YTCY_1-4 possess antioxidative properties. These peptides have a strong effect on Cutibacterium acnes (C. acnes) and significantly inhibit Staphylococcus aureus. The inhibition rate of biofilm adhesion of YT-EPs to C. acnes reached 50% under the MIC. It was found that YTCY-EPs possess strong antioxidant and anti-inflammatory properties. It can effectively reduce active oxygen nearly 3 times and can reduce the downstream TLR2/NF-κB and MAPKs/AP-1 pathways by regulating the nuclear translocation of NF-κB and AP-1 in vitro. The transcriptional expression of inflammatory cytokines, inflammatory chemokines, and matrix metalloproteinase genes is also regulated, thereby slowing the recruitment of inflammatory cells and the development of inflammation, and increasing keratinocyte mobility. In addition, the expression levels of inflammatory factors and matrix metalloproteinases in the rabbit ears with acne problems that were tested with YTCY-EPs were significantly reduced, and it was obviously observed that the rabbit ear inflammation, acne, and keratinization problems were repaired. The results of this study prove that YTCY-EPs can be used as a potential anti-acne raw material in cosmetics.