Molecular regulation of the intestinal epithelial barrier: implication in human diseases.

Intestinal barrier dysfunction is implicated in the development of various clinical diseases. While the study of intestinal barrier function has traditionally emphasized the impact of intestinal microflora and bacteria, the rapid development of molecular and cellular techniques has helped the recent transition of the field to the molecular regulation of the intestinal epithelial barrier. In this review, we summarized several aspects of recent progress on the molecular regulation of the intestinal epithelial barrier, ranging from the extrinsic factors such as probiotics, intrinsic protein effectors including the tight junction proteins, intestinal alkaline phosphatase and protein phosphatase 2A, to intestinal cell subsets such as intestinal intraepithelial lymphocytes and intestinal stem cells. Further investigations into the detailed mechanisms underlying the molecular regulation of the intestinal epithelial barrier will enable our manipulation of the factors and cell subsets involved to develop effective approaches to treat intestinal barrier dysfunction associated diseases.