Identification of miRNA-497 and miRNA-27b-5p as potential diagnostic markers of cardiac fibrosis

Abstract Background Cardiac fibrosis is associated with inflammation and extracellular matrix (ECM) accumulation. A pro-fibrotic cytokine, IL11 induces cardiac fibroblasts conversion to myofibroblasts expressing α-smooth muscle actin (α-SMA) and ECM. MicroRNAs (miRNAs) are a class of small non-coding RNAs which participate in regulation of gene expression; Although mainly intracellular, miRNAs can be released into the blood stream where they can be readily detected. Purpose To screen miRNAs upregulated following IL11 triggered conversion of rat cardiac fibroblasts into myofibroblasts. To validate these miRNAs as potential diagnostic biomarkers of cardiac fibrosis by testing their level in blood plasma and septum of aortic valve stenosis (AVS) patients. Methods and results With a bioinformatical approach (Figure 1), we predicted miRNAs which can target proteins involved in TGFβ and IL-11 pathways of fibrosis progression. Of a vast number of miRNAs, we identified 7 strong candidates. After qPCR validation, we found miRNA-27b-5p and miRNA-497 to be significantly upregulated in rat cardiac fibroblasts treated by IL11 (5 ng/ul) but not TGFβ1 (100 ng/ul), values are 2–ΔΔCt: (3±1.5) and (5.2±2.2) (p-value