New emerging tasks for microRNAs in the control of β-cell activities

MicroRNAs are key regulators of (beta-cell physiology. They participate to the differentiation of insulin-producing cells and are instrumental for the acquisition of their unique secretory properties. Moreover, they contribute to the adaptation of beta-cells to conditions of increased insulin demand and, if expressed at inappropriate levels, certain microRNAs cause beta-cell dysfunction and promote the development of different forms of diabetes mellitus. While these functions are increasingly better understood, additional tasks for these small non-coding RNAs have been recently unveiled. Thus, microRNAs are emerging as signaling molecules of a novel exosomemediated cell-to-cell communication mode permitting a coordinated response of the beta-cells to inflammatory conditions and to modifications in the insulin demand. These discoveries raise a number of important issues that once addressed promise to shed new light on the molecular mechanism governing the functions of the beta-cells under normal and disease states. This article is part of a Special Issue entitled: MicroRNAs and lipid/energy metabolism and related diseases edited by Carlos Fernandez-Hernando and Yajaira Suarez. (C) 2016 Elsevier B.V. All rights reserved.