Mucosal Prevalence and Interactions with the Epithelium Indicate Commensalism ofSutterellaspp.
Sutterellaspecies have been frequently associated with human diseases, such as autism, Down syndrome, and inflammatory bowel disease (IBD), but the impact of these bacteria on health still remains unclear. Especially the interactions ofSutterellaspp. with the host are largely unknown, despite of the species being highly prevalent. In this study, we addressed the interaction of three known species ofSutterellawith the intestinal epithelium and examined their adhesion properties, the effect on intestinal barrier function and the pro-inflammatory capacityin vitro. We also studied the relative abundance and prevalence of the genusSutterellaandSutterella wadsworthensisin intestinal biopsies of healthy individuals and patients with celiac disease (CeD) or IBD. Our results show thatSutterellaspp. are abundant in the duodenum of healthy adults with a decreasing gradient toward the colon. No difference was detected in the prevalence ofSutterellabetween the pediatric IBD or CeD patients and the healthy controls.Sutterella parvirubraadhered better than the two otherSutterellaspp. to differentiated Caco-2 cells and was capable of decreasing the adherence ofS. wadsworthensis, which preferably bound to mucus and human extracellular matrix proteins. Furthermore, onlyS. wadsworthensisinduced an interleukin-8 production in enterocytes, which could be due to different lipopolysaccharide structures between the species. However, its pro-inflammatory activity was modest as compared to non-pathogenicEscherichia coli.Sutterellaspp. had no effect on the enterocyte monolayer integrityin vitro. Our findings indicate that the members of genusSutterellaare widely prevalent commensals with mild pro-inflammatory capacity in the human gastrointestinal tract and do not contribute significantly to the disrupted epithelial homeostasis associated with microbiota dysbiosis and increase of Proteobacteria. The ability ofSutterellaspp. to adhere to intestinal epithelial cells indicate that they may have an immunomodulatory role.
Immunobiology Research Program, Faculty of Medicine, University of Helsinki Helsinki, Finland.
Kaisa
K
Hiippala
Pharmacology, Faculty of Medicine, University of Helsinki Helsinki, Finland.
Veera
V
Kainulainen
Department of Pediatrics, Turku University Central Hospital and Functional Foods Forum, University of Turku Turku, Finland.
Marko
M
Kalliomäki
Department of Gastroenterology, Helsinki University Central Hospital Helsinki, Finland.
Perttu
P
Arkkila
Immunobiology Research Program, Faculty of Medicine, University of Helsinki Helsinki, Finland.
Reetta
R
Satokari
Proteobacteria; Sutterella; adherence; commensal; gut inflammation; host–microbe interaction