ABSTRACT
Commensal and Probiotics-Host Interactions Team, INRA, UMR 1319 MICALIS, Domaine de Vilvert, F-78350 Jouy-en-Josas, France.
E-mails: claire.cherbuy@jouy.inra.fr; julie.tomas@jouy.inra.fr; muriel.thomas@jouy.inra.fr * Corresponding author: philippe.langella@jouy.inra.fr
The mammalian intestine is in constant contact with a vast array of commensal bacteria and faces the challenge of having to maintain its capacity to respond to intestinal pathogens while ensuring that the infl ammatory response to commensal organisms is minimal (Garrett et al. 2010; Hooper and Macpherson 2010). The intestinal epithelium is at the crossroads between the gut microbiome and the host, and the intestinal epithelial cells (IECs) play a major role in tolerance to commensal microbes (Goto and Kiyono 2012). The multiple specialized intestinal epithelial lineages are called upon to develop a rich array of essential strategies for sustaining the complex and dynamic microbial communities of the intestine. Preservation of the functions of the intestinal epithelium is important, as shown by genome-wide association studies linking loci implicated in epithelial barrier function with infl ammatory bowel diseases (IBD)
(Cho and Brant 2011). A recent study in B cell-defi cient mice showed that failure of the adaptive immune system led to commensal bacteria forcing IECs to upregulate genes controlling immunity at the expense of those regulating metabolism, revealing an additional level of complexity in the crosstalk between microbiota and the intestinal epithelium (Shulzhenko et al. 2011).
