MicroRNAs in idiopathic inflammatory myopathies: state-of-the-art and future perspectives

Purpose of review: Idiopathic inflammatory myopathies (IIMs) are a group of rare autoimmune disorders characterized by muscle weakness and inflammation. MicroRNAs (miRNAs) are the main class of small noncoding RNAs regulating a wide range of physiological and pathological processes and play a role in mediating autoimmunity and inflammation. In this review, we summarize the latest knowledge on the role of miRNAs in systemic autoimmune diseases with particular focus on IIMs. Recent findings: Study on miRNA expression in IIMs is helping in understanding the pathogenetic basis of the disease at a tissue and systemic level. Several miRNAs, even with a muscle-specific expression (myomiRs), have been shown to be involved in immune and nonimmune mechanisms of myofiber damage. MiRNAs modulate and orchestrate the local inflammatory infiltrate and could be used as potential biomarkers as they correlate with disease activity and response to therapy. Summary: IIMs comprise different clinical phenotypes and still little is known about the molecular signature of each subset. Further research about miRNA profiling will provide additional insights in the disease characterization with an expected impact on the therapeutic strategies.