Intestinal epithelial cells: at the interface of the microbiota and mucosal immunity

Abstract

Summary The intestinal epithelium forms a barrier between the microbiota and the rest of the body. In addition, beyond acting as a physical barrier, the function of intestinal epithelial cells (IECs) in sensing and responding to microbial signals is increasingly appreciated and likely has numerous implications for the vast network of immune cells within and below the intestinal epithelium. IECs also respond to factors produced by immune cells, and these can regulate IEC barrier function, proliferation and differentiation, as well as influence the composition of the microbiota. The mechanisms involved in IEC–microbe–immune interactions, however, are not fully characterized. In this review, we explore the ability of IECs to direct intestinal homeostasis by orchestrating communication between intestinal microbes and mucosal innate and adaptive immune cells during physiological and inflammatory conditions. We focus primarily on the most recent findings and call attention to the numerous remaining unknowns regarding the complex crosstalk between IECs, the microbiota and intestinal immune cells.

Toll-Like Receptor 4 Signaling in the Ileum and Colon of Gnotobiotic Piglets Infected with Salmonella Typhimurium or Its Isogenic ∆rfa Mutants

“…CRP served in our study as "a classical" inflammatory marker that has been used by clinicians for decades [91]. The synthesis of CRP in the liver [92] was the reason that we did not measure its intestinal levels, as in the case of cytokines that are produced by different cell populations, including intestinal epithelial cells [20,93].…”

Dietary Supplementation with Spray-Dried Porcine Plasma Attenuates Colon Inflammation in a Genetic Mouse Model of Inflammatory Bowel Disease

“…Dysfunction of the innate and adaptive immune responses triggers the release of numerous proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ), which results in epithelial cell damage and apoptosis and alteration of the epithelial barrier [ 4 ]. The epithelial barrier comprises epithelial cells (enterocytes), tight junction proteins, and the mucosal layer [ 6 ] and constantly interacts with the underlying immune cells of the GALT [ 7 ]. In IBD patients, the integrity of the epithelial barrier is compromised, as shown by increased paracellular permeability and lower levels of tight junction proteins [ 8 ].…”

Structure and Function of Bovine Whey Derived Oligosaccharides Showing Synbiotic Epithelial Barrier Protective Properties

“…Intestinal epithelial cells are at the forefront of this, in mutual alliance with the gut microbial ecosystem. Today, increasing experimental data shows that intestinal epithelial cells are not only a physical barrier, but that these cells play crucial regulatory roles in the defensive systems that are at the interface between the host and the environment [ 6 ]. Reciprocal sensing is the hallmark of host-microbiota crosstalk, and its subsequent effects on host health.…”