MicroRNAs in immune response and macrophage polarization

Abstract

Inflammation is essential to combat invading microbial pathogens. In this process, the involvement of multiple immune cell populations is crucial in mounting an optimum immune response. In the past decade, a new class of noncoding small RNAs, called microRNAs (miRNAs), has emerged as important regulators in biological processes. The important role of miRNAs in inflammation and immune response is highlighted by studies in which deregulation of miRNAs was demonstrated to accompany diseases associated with excessive or uncontrolled inflammation. In this brief review, we summarize the roles of miRNAs that have been characterized in innate and adaptive immune responses. We discuss the role of miRNAs in macrophage polarization, a molecular event that has clear effect on inflammation.

Figure 1

A few miRNAs, such as miR-124, miR-155 and miR-223, have been identified to regulate both M1 and M2 macrophage polarization. However, it is unknown if the large number of miRNAs that regulate inflammatory response also modulate macrophage plasticity.