Identifying the differentially expressed microRNAs in autoimmunity: A systemic review and meta-analysis

The evidence indicates that microRNAs (miRNAs) can regulate gene expression and play an important role in the pathogenesis of autoimmune diseases, yet studies on expression profiles of miRNAs are still inconclusive. Our objective is to identify miRNAs that demonstrate enduring differential expression on autoimmune diseases. A systemic review and meta-analysis were performed by analysing the expression profile of miRNAs in several types of autoimmune disease, including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and type-1 diabetes (T1D). Several most significant differentially expressed miRNAs were identified and showed significant deregulation in autoimmune diseases. The most compelling results for SLE were with miR-21, miR-148a, miR-223, miR-125b in blood and miR-26a in kidney samples, for RA, miR-21, miR-24, miR-26a, miR-155 and miR-223 in blood, and for T1D, miR-148a, miR-181a in blood and miR-21, miR-155 in urine samples. Interestingly, some of miRNAs were differentially expressed in more than one autoimmune disease, such as miR-21, miR-26a, miR-155, miR-148a, miR-223. These miRNAs are commonly associated with the immune response and increases in the activity of the immune system and inflammation in specific organs such as skin, joint, lung, and kidney. These miRNAs can potentially be not only good biomarkers for the prediction, diagnosis, but also therapeutic targets in autoimmune diseases.