Interplay between dysregulated immune system and the footprints of blood-borne miRNAs in treatment naive Crohn's disease and ulcerative colitis patients

Methods

High-throughput small RNA sequencing was conducted to quantify circulating miRNAs in 27 participants (8 CD, 10 UC and 9 healthy volunteers). To describe immune-dysregulation, circulating T-cell related cytokines were determined via bead array. Additionally, in IBD patients, the distribution of T cell subpopulations was also determined in circulation and in tissue biopsy samples using multicolor flow cytometry.

Results: Based on small RNA sequencing results, 14 miRNAs showed significant expression differences between IBD and control group after qRT-PCR validation. Five miRNAs were found to exhibit significantly different expression and high discriminatory potential (AUC:0.7-1) between CD and UC patients. Furthermore, circulating IL-22 and IFN-γ levels were significantly higher in IBD.

Notably, miRNAs exhibited several strong negative and positive correlations with cytokine levels and with T-cell subset distribution in circulation and tissue samples, with disease specific association pattern. Conclusion: We identified differentially expressed miRNAs in IBD patients’ groups. A subset of these miRNAs shows promising diagnostic value for distinguishing CD from UC.

Thereby scrutinizing miRNA expression in blood samples of IBD patients might holds diagnostic and monitoring potential. Our results confirmed that, dysregulated miRNAs reflect the underlying immune dysregulation and may contribute to IBD diseases pathology.