Plasma miRNA Profile of Crohn’s Disease and Rheumatoid Arthritis Patients

SIMPLE SUMMARY: MicroRNAs are small, noncoding RNA, around 23 nt long molecules, expressed in different cell types and involved in post-transcriptional regulation. Importantly, these unique molecules can act directly in cells expressing them, but can also be secreted into blood affecting gene expression in distant or adjacent target cells, thus representing valuable circulating biomarkers of different diseases. In addition, miRNA gene target prediction indicates the important role in pathogenesis of a variety of autoimmune diseases, including Crohn’s disease (CD) and rheumatoid arthritis (RA). Our study of blood circulating miRNAs indicated that there are 99 differentially expressed miRNAs in CD patients and 57 in RA patients, when comparing with healthy individuals. This high number of differentially expressed miRNAs in both autoimmune diseases allowed us to select over 400 different biological processes that were similarly regulated between both groups of patients, which can pave the way to future mechanistic studies for better diagnosis or treatment for patients with Crohn’s disease and rheumatoid arthritis. ABSTRACT: Crohn’s disease (CD) and rheumatoid arthritis (RA) are immune mediated inflammatory diseases. Several studies indicate a role for microRNAs (miRNAs) in the pathogenesis of a variety of autoimmune diseases, including CD and RA. Our study’s goal was to investigate circulating miRNAs in CD and RA patients to identify potential new biomarkers for early detection and personalized therapeutic approaches for autoimmune diseases. For this study, subjects with CD (n = 7), RA (n = 8) and healthy controls (n = 7) were recruited, and plasma was collected for miRNA sequencing. Comparison of the expression patterns of miRNAs between CD and healthy patients identified 99 differentially expressed miRNAs. Out of these miRNAs, 4 were down regulated, while 95 were up regulated. Comparison of miRNAs between RA and healthy patients identified 57 differentially expressed miRNAs. Out of those, 12 were down regulated, while 45 were up regulated. For all the miRNAs down regulated in CD and RA patients, 420 GO terms for biological processes were similarly regulated between both groups. Therefore, the identification of new plasma miRNAs allows the emergence of new biomarkers that can assist in the diagnosis and treatment of CD and RA.