Abstract
Introduction: microRNAs (miRNAs) have recently been emerged as important regulatory molecules in Cystic Fibrosis (CF) disease in which airways tissues/organs are often characterized by severe inflammation and recurrent infections. Therefore, miRNA aberrant expression might explain the wide phenotypic variability observed in CF patients. Aims and Objectives: In order to comprehend the role of miRNAs in the CF pathogenesis, we analyzed the expression of specific miRNAs in nasal epithelia of CF patients and healthy controls. Methods: miRNA and mRNA levels were measured by quantitative real time PCR (Q-PCR) using the relative quantification 2−ΔΔCT method. Computational prediction algorithms and luciferase reporter assays were used to identify putative targets of miR-145. Results: miR-145 was significantly up-regulated in nasal epithelial tissues from CF patients compared with healthy subjects (p< 0.001). We predicted SMAD3, a key element of the TGF-beta1 inflammatory pathway, as a target of miR-145. Indeed, luciferase reporter assays showed that miR-145 synthetic mimics suppressed by approximately 40% the expression of a reporter construct containing the SMAD3 3'-untranslated region. In addition, we observed an inverse correlation between SMAD3 mRNA expression and miR-145 in CF nasal tissues (r=-0.68, p=0.0018, Pearson's correlation). Conclusions: Our data confirm the importance of miRNAs in the CF pathogenesis and suggest that miRNA deregulation plays a role in the airway disease severity by modulating the expression of molecules involved in the inflammatory response. Therefore, miR-145 may be not only a novel biomarker but also potential tool in order to target specific CF clinical manifestations.
- © 2013 ERS