A similar pattern was observed in the current study in WT but not MMP-9−/− mice, as the fecal microbiota of the latter group had no changes in diversity following infection. Colonization of the cecal mucosa by the murine pathogen Helicobacter hepaticus also reduces microbial diversity [38]. The distinct and stable fecal microbiome in MMP-9−/− mice identified in this study emphasizes NCT-501 purchase that the presence of MMP-9 in mouse colon supports a microbiome that

is more susceptible to C. rodentium colonization and reductions in microbial diversity. Given that MMP-9−/− (B6.FVB(Cg)-Mmp9 tm1Tvu /J) mice have a microbiota that is more resistant to C. rodentium colonization, this genotype should prove useful for future studies evaluating the contribution of microbe-microbe interactions to the pathogenesis of C. rodentium

infection and the maintenance of microbial diversity. The role of other MMPs in maintaining the fecal microbiota upon infectious challenge will also prove to be of interest in future experimental studies. Conclusions Microbe-microbe and host-microbe interactions are essential for maintaining gut health [1]. Although studies have shown that expression of matrix metalloproteinase 9 is associated with IBD, the influence of MMP-9 expression on gut microbial community dynamics has not been studied in vivo. This work demonstrates that, in a model of bacterial-induced colitis, the particular microbial community of MMP-9−/− mice Ilomastat order contributes to reduced levels of C. rodentium preventing a reduction in the microbial diversity associated with infection [21]. An altered intestinal ecosystem may lead to changes in some of the protective, metabolic, structural and histological functions of the gut microbiome [39], which has driven scientists to develop unique microbial signatures that describe IBD [4].

Further analysis of the interaction between the microbiome and other MMPs upregulated in IBD [1–3, 8, 12] are required to yield further insight into microbe-microbe and host-microbe interactions. Methods Bacterial strains and growth conditions before C. rodentium, strain DBS 100 (generously provided by the late Dr. David Schauer, Massachusetts Institute of Technology, Cambridge, MA) was grown on Luria-Bertani (LB) agar plates overnight at 37°C, followed by overnight culture in LB broth at 37°C without shaking, yielding a final bacterial concentration of approximately 109 colony-forming units (CFU)/mL. Mouse strains and bacterial infection Male and female wild-type (C57BL/6 J) and MMP-9−/− (B6.FVB(Cg)-Mmp9 tm1Tvu /J) mice aged 5–6 weeks were purchased (Jackson Laboratory, Bar Harbour, ME) and housed in the BAY 11-7082 cell line containment unit of Laboratory Animal Services at the Hospital for Sick Children in cages containing a maximum of 5 mice per cage. All mice were allowed free access to food and water (supplied from a controlled source) for the duration of the study protocol.