Differential expression profile of miRNAs and piRNAs in asthmatic and non-asthmatic bronchial smooth muscle cells reveals new possible biomarkers for complex lung diseases

Bronchial smooth muscle (BSM) cells are the effector cells of bronchoconstriction and a potent source of inflammatory mediators and angiogenic factors. Small non-coding (snc)RNAs, such as microRNAs (miRNAs) and PIWI-interacting RNAs (piRNAs) are transcriptional and post-transcriptional regulators of gene expression. Abbarently expressed, they may play a role in airway diseases and/or provide novel biomarkers to characterize lung pathologies. To assess the miRNAs and piRNAs expression profiles of primary human BSM cells of asthmatic (n=8) and non-asthmatic (n=6) individuals. Library preparation was performed with Illumina TruSeq small RNA sample preparation protocol. Sized smallRNA libraries were gel purified and sequenced on Illumina HiSeq 1500. iMir [BMC Bioinformatics, Dec 2013, 13; 14:362) was used to identify sncRNAs and perform differential expression analysis. BSM cells of both asthmatics and non-asthmatics expressed 892 and 122 known miRNAs and piRNAs, respectively. 33 miRNAs were differentially expressed in asthmatic vs non-asthmatic BSM cells (p≤0.05, fold-change cut-off≥1.5) and among them 27 were up-regulated and 6 down-regulated. Furthermore, 1 piRNA was found significantly down regulated in BSM cells from asthmatic patients. We conclude that BSM cells from both asthmatics and non-asthmatics are characterized by distinctly different pools of miRNAs and piRNAs. Differential expression of miRNAs and piRNAs may contribute to, and/or explain, the development of airway diseases and provide novel biomarkers to characterize and discriminate between lung pathologies at an early stage of the diseases.