title: Akkermansia muciniphila Adheres to Enterocytes and Strengthens the Integrity of the Epithelial Cell Layer.
abstract: Akkermansia muciniphila is a Gram-negative mucin-degrading bacterium that resides in the gastrointestinal tracts of humans and animals. A. muciniphila has been linked with intestinal health and improved metabolic status in obese and type 2 diabetic subjects. Specifically, A. muciniphila has been shown to reduce high-fat-diet-induced endotoxemia, which develops as a result of an impaired gut barrier. Despite the accumulating evidence of the health-promoting effects of A. muciniphila, the mechanisms of interaction of the bacterium with the host have received little attention. In this study, we used several in vitro models to investigate the adhesion of A. muciniphila to the intestinal epithelium and its interaction with the host mucosa. We found that A. muciniphila adheres strongly to the Caco-2 and HT-29 human colonic cell lines but not to human colonic mucus. In addition, A. muciniphila showed binding to the extracellular matrix protein laminin but not to collagen I or IV, fibronectin, or fetuin. Importantly, A. muciniphila improved enterocyte monolayer integrity, as shown by a significant increase in the transepithelial electrical resistance (TER) of cocultures of Caco-2 cells with the bacterium. Further, A. muciniphila induced interleukin 8 (IL-8) production by enterocytes at cell concentrations 100-fold higher than those for Escherichia coli, suggesting a very low level of proinflammatory activity in the epithelium. In conclusion, our results demonstrate that A. muciniphila adheres to the intestinal epithelium and strengthens enterocyte monolayer integrity in vitro, suggesting an ability to fortify an impaired gut barrier. These results support earlier associative in vivo studies and provide insights into the interaction of A. muciniphila with the host.
authors: Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.
authors: Justus
authors: J
authors: Reunanen
authors: Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.
authors: Veera
authors: V
authors: Kainulainen
authors: Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.
authors: Laura
authors: L
authors: Huuskonen
authors: Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands.
authors: Noora
authors: N
authors: Ottman
authors: Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands.
authors: Clara
authors: C
authors: Belzer
authors: Division of Digestive Surgery and Urology, Turku University Hospital, Turku, Finland.
authors: Heikki
authors: H
authors: Huhtinen
authors: Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland.
authors: Willem M
authors: WM
authors: de Vos
authors: Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland Functional Foods Forum, University of Turku, Turku, Finland reetta.satokari@helsinki.fi.
authors: Reetta
authors: R
authors: Satokari
mesh_terms: D001422:Bacterial Adhesion; D002460:Cell Line; D020895:Enterocytes / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D004847:Epithelial Cells / Q000502:physiology*; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D061327:Verrucomicrobia / Q000276:immunology / Q000502:physiology*
chemical_list: D016209:Interleukin-8