MicroRNAs in the Intestine: Role in Renewal, Homeostasis, and Inflammation.

The mammalian intestine is not only an organ for food digestion and nutrient absorption but also an integral part of the immune and endocrine systems. The intestinal epithelium under stressful environments requires epithelial cells to rapidly elicit changes in gene expression patterns to regulate their survival, adapt to stress, and maintain epithelial homeostasis. Recently, miRNAs have emerged as a novel class of posttranscriptional gene regulators that are fundamentally involved in many aspects of intestinal epithelial differentiation, architecture, and barrier function. In this review, we highlight the critical roles of miRNAs in both the crypt-villus axis of cellular self-renewal and inflammation in the mammalian intestinal mucosa and their impact on the microbiota. We also discuss the functions of specific miRNAs within the intestine to better understand the cellular mechanisms that promote intestinal homeostasis, and the influence of dietary components in the regulation of endogenous miRNA in the study of nutrition and gene regulation in intestinal health.