Presenter(s): Lila Kaye − Biology, Emphasis In Cellular And Mollecular
Faculty Mentor(s): Karen Guillemin, Kristi Hamilton
Poster 50
Research Area: Microbiology
Funding: SPUR 2016, VPRI 2017, Meta, NIH
The microbiota of the gastrointestinal tract is critical for the development and regulation of the host immune system. Some bacterial genera are associated with health and homeostasis, while others have been linked to inflammation and disease. There have been many studies in recent literature investigating the potential role of commensal microbes in autoimmune and gastrointestinal diseases, both preventative and pathogenic. Much less is known, however, about how interactions with the immune system benefit resident microbes. Here I used the zebrafish, Danio rerio, as a powerful gnotobiotic model for investigating host-microbe symbiosis. I investigated the novel immunoregulatory protein aimA, produced by the zebrafish commensal Aeromonas, and show that it facilitates mutualism with the host by reducing gastrointestinal inflammation and increasing bacterial intestinal colonization in both monoassociations and co-inoculation with pro-inflammatory species Vibrio. Using GFP-tagged neutrophils as a reporter for inflammation, I showed that a deletion mutant lacking the gene for AimA (∆aimA) is unable to regulate host immune response and cannot colonize the gut as robustly. Inoculation into immunocompromised MyD88-/-hosts having decreased intestinal inflammation rescues the colonization defect suffered in the absence of aimA, demonstrating reciprocity between control of the host biology and control of the resident bacterial biology. Identification of bacterial products involved in establishing a healthy symbiosis with the host is crucial for understanding how commensal communities are assembled and maintained.