Enteric glial cells and their role in the intestinal epithelial barrier

Abstract

The intestinal epithelium constitutes a physical and functional barrier between the external environment and the host organism. It is formed by a continuous monolayer of intestinal epithelial cells maintained together by intercellular junctional complex, limiting access of pathogens, toxins and xenobiotics to host tissues. Once this barrier integrity is disrupted, inflammatory disorders and tissue injury are initiated and perpetuated. Beneath the intestinal epithelial cells lies a population of astrocyte-like cells that are known as enteric glia. The morphological characteristics and expression markers of these enteric glia cells were identical to the astrocytes of the central nervous system. In the past few years, enteric glia have been demonstrated to have a trophic and supporting relationship with intestinal epithelial cells. Enteric glia lesions and/or functional defects can be involved in the barrier dysfunction. Besides, factors secreted by enteric glia are important for the regulation of gut barrier function. Moreover, enteric glia have an important impact on epithelial cell transcriptome and induce a shift in epithelial cell phenotype towards increased cell adhesion and cell differentiation. Enteric glia can also preserve epithelial barrier against intestinal bacteria insult. In this review, we will describe the current body of evidence supporting functional roles of enteric glia on intestinal barrier.

Keywords: Enteric glia cells; Intestinal epithelial cells; Intestinal barrier function; Tight junctions

Core tip: This review offers a state-of-the-art discussion on the role of enteric glial cells (EGCs), an intriguing population of astrocyte-like cells within the gastrointestinal tract, on the regulation of intestinal epithelial barrier. The discussion will shed light on the novel mechanisms of EGC-intestinal epithelial cells interactions, which is invaluable in ultimately developing new therapeutic tools for the restoration of the intestinal barrier functions.