Physiological and pathological roles for microRNAs: implications for immunity complications

MicroRNAs (miRNAs) are small non-coding regulatory RNAs molecules with a size of approximately 22 nucleotides that are implicated in regulating gene expression at the post-transcriptional regulatory levels. Inflammatory disorders especially autoimmune diseases (ADs) occur from an abnormal immune response of body against cells of their own specific tissues or multiple organ systems leading to chronic and sustain inflammatory responses and thus contribute to cell damage. Some recent studies have reported that several miRNAs may be expressed differentially in ADs and other inflammatory diseases which can have a critical role in immune response modulation and autoimmunity. This review is focused on the role of miRNAs in the pathogenesis and progression of several autoimmune diseases.