BioProject

Objective: MicroRNAs (miRNAs) control key elements of mRNA stability and likely contribute to the dysregulated lung gene expression observed in systemic sclerosis associated interstitial lung disease (SSc-ILD). We analyzed the miRNA gene expression of tissue and cells from SSc-ILD patients. A chronic lung fibrotic murine model was used. Methods: RNA was isolated from lung tissue of 12 SSc-ILD patients and 5 control lungs. High-resolution computed tomography (HRCT) was performed at baseline and 2-3 years after treatment. Lung fibroblasts and PBMCs were isolated from healthy controls and SSc-ILD patients. miRNA and mRNA were analyzed by microarray, quantitative polymerase chain reaction, and/or Nanostring; pathway analysis was performed by DIANA-miRPath v2.0 software. Wild-type and miR-155 deficient (miR-155ko) mice were exposed to bleomycin. Results: Lung miRNA microarray data distinguished patients with SSc-ILD from healthy controls with 185 miRNA differentially expressed (q<0.25). DIANA-miRPath revealed 57 KEGGs pathways related to the most dysregulated miRNAs. miR-155 and miR-143 were strongly correlated with progression of the HRCT score. Lung fibroblasts showed only mild expression of miR-155/miR-21 after several stimuli. miR-155 PBMC expression strongly correlated with lung function tests in SSc-ILD. miR-155ko mice developed milder lung fibrosis, survived longer, and showed a weaker lung induction of several genes after bleomycin exposure compared to wild-type mice. Conclusions: miRNAs are dysregulated in lungs and PBMCs of SSc-ILD patients. Based on mRNA-miRNA interaction analysis and pathway tools, miRNAs may play a role in the progression of the disease. Our findings suggest that targeting miR-155 might provide a novel therapeutic strategy for SSc-ILD. Overall design: Lung biopsies taken from open lung biopsy from SSc-ILD patients (n=15 samples) and from cancer free control patients (n=5) during ressection of the lung tumor.