Host lysozyme-mediated lysis of Lactococcus lactis facilitates delivery of colitis-attenuating superoxide dismutase to inflamed colons.

Abstract

Beneficial microbes that target molecules and pathways, such as oxidative stress, which can negatively affect both host and microbiota, may hold promise as an inflammatory bowel disease therapy. Prior work showed that a five-strain fermented milk product (FMP) improved colitis in T-bet(-/-) Rag2(-/-) mice. By varying the number of strains used in the FMP, we found that Lactococcus lactis I-1631 was sufficient to ameliorate colitis. Using comparative genomic analyses, we identified genes unique to L. lactis I-1631 involved in oxygen respiration. Respiration of oxygen results in reactive oxygen species (ROS) generation. Also, ROS are produced at high levels during intestinal inflammation and cause tissue damage. L. lactis I-1631 possesses genes encoding enzymes that detoxify ROS, such as superoxide dismutase (SodA). Thus, we hypothesized that lactococcal SodA played a role in attenuating colitis. Inactivation of the sodA gene abolished L. lactis I-1631's beneficial effect in the T-bet(-/-) Rag2(-/-) model. Similar effects were obtained in two additional colonic inflammation models, Il10(-/-) mice and dextran sulfate sodium-treated mice. Efforts to understand how a lipophobic superoxide anion (O2 (-)) can be detoxified by cytoplasmic lactoccocal SodA led to the finding that host antimicrobial-mediated lysis is a prerequisite for SodA release and SodA's extracytoplasmic O2 (-) scavenging. L. lactis I-1631 may represent a promising vehicle to deliver antioxidant, colitis-attenuating SodA to the inflamed intestinal mucosa, and host antimicrobials may play a critical role in mediating SodA's bioaccessibility.

• Authors: Sonia A Ballal, Patrick Veiga, Kathrin Fenn, Monia Michaud, Jason H Kim, Carey Ann Gallini, Jonathan N Glickman, Gaëlle Quéré, Peggy Garault, Chloé Béal, Muriel Derrien, Pascal Courtin, Saulius Kulakauskas, Marie-Pierre Chapot-Chartier, Johan van Hylckama Vlieg, Wendy S Garrett
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 112 Issue 25 Pg. 7803-8 (Jun 23 2015) ISSN: 1091-6490 [Electronic] United States
• PMID: 26056274 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Reactive Oxygen Species
• Superoxide Dismutase
• Muramidase

Topics

• Animals
• Colitis (enzymology, metabolism, microbiology)
• Intestinal Mucosa (enzymology, metabolism, microbiology)
• Lactococcus lactis (metabolism)
• Mice
• Muramidase (metabolism)
• Reactive Oxygen Species (metabolism)
• Superoxide Dismutase (metabolism)