Zooming in on Inflammatory Bowel Disease: Microbial and Proteomic Features Associated With IBD in Colonic Microenvironments

Inflammatory bowel disease (IBD) is a multifactorial chronic intestinal inflammatory disorder characterized both by genetic and environmental factors.1 Among the latter, the microbiome recently emerged as one of the most promising avenues of research to understand the pathogenesis of IBD. Several studies have shown differences in microbiome composition and diversity in IBD patients compared with healthy controls.2, 3 Larger cohorts have allowed for further characterization of the gut microbiota in IBD patients, including assays that determine function and activity of the microbiome and thus provide better mechanistic insights.4, 5, 6 Most of these studies, however, investigated microbial composition in stool or in the colonic mucosal surface, missing potentially important factors hidden in deeper layers of the colon. Furthermore, we still lack a good understanding of how the microbiome interacts with the host at the proteomic level. The September issue of Cellular and Molecular Gastroenterology and Hepatology presents 2 new exciting articles that highlight the importance of in situ microbiome structure in deep colonic layers and metaproteomic functional networks in the characterization of IBD