A secreted bacterial peptidoglycan hydrolase enhances tolerance to enteric pathogens

• Published in: Science (American Association for the Advancement of Science) Vol. 353; no. 6306; pp. 1434 - 1437
• Main Authors: Rangan, Kavita J., Pedicord, Virginia A., Wang, Yen-Chih, Kim, Byungchul, Lu, Yun, Shaham, Shai, Mucida, Daniel, Hang, Howard C.
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 23.09.2016; The American Association for the Advancement of Science
• Subjects: Animals; Antigens; Antigens, Bacterial - immunology; Bacteria; Bacterial Proteins - immunology; Caenorhabditis elegans; Caenorhabditis elegans - immunology; Caenorhabditis elegans - microbiology; Caenorhabditis elegans Proteins; Enterococcus faecium; Enterococcus faecium - enzymology; Enterococcus faecium - immunology; Fragments; Gastrointestinal Microbiome - immunology; Host-Pathogen Interactions - immunology; Mice; Mice, Inbred C57BL; Models, Biological; N-Acetylmuramoyl-L-alanine Amidase - immunology; Nerve Tissue Proteins; Pathogenesis; Pathogens; Probiotics; Salmonella; Salmonella Infections - prevention & control; Salmonella typhimurium - immunology; Tolerances
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.aaf3552

The intestinal microbiome modulates host susceptibility to enteric pathogens, but the specific protective factors and mechanisms of individual bacterial species are not fully characterized. We show that secreted antigen A (SagA) from Enterococcus faecium is sufficient to protect Caenorhabditis elegans against Salmonella pathogenesis by promoting pathogen tolerance. The NlpC/p60 peptidoglycan hydrolase activity of SagA is required and generates muramylpeptide fragments that are sufficient to protect C. elegans against Salmonella pathogenesis in a tol-1-dependent manner. SagA can also be heterologously expressed and secreted to improve the protective activity of probiotics against Salmonella pathogenesis in C. elegans and mice. Our study highlights how protective intestinal bacteria can modify microbialassociated molecular patterns to enhance pathogen tolerance.