The curious case of miR-155 in SLE

Epigenetic modifications have been well documented in autoimmune diseases. MicroRNAs (miRNAs), in particular, have long intrigued scientists in the field of autoimmunity. Owing to its central role in the development of the immune system, microRNA-155 (miR-155) is deeply involved in systemic lupus erythematosus (SLE). Despite the advancements made in treating SLE, the disease still remains incurable. Therefore, recent attention has been drawn to the manipulation of epigenetics in the development of curative treatments. In fact, it is a widely held view that miRNA-targeted therapy is a new glimmer of hope in the treatment of autoimmune diseases. However, the duplicity of miRNAs should not be overlooked. A single miRNA can target several mRNAs, and some mRNAs may possess opposing functions. In this review, we highlight the role of miR-155 as a biomarker and review its functions in SLE patients and animal models while discussing possible reasons behind inconsistencies across studies.