ADAR1 is significantly downregulated in IPF fibroblasts; the overexpression of ADAR1 and ADAR2 reestablishes the expression levels of miRNA-21, PELI1, and SPRY2 in fibroblasts of patients with IPF.
The sequences of the dysregulated microRNAs in IPF including miR-21, miR-31, miR-101, miR-29, miR-199, and let-7d were used to search NONCODE database containing 33,829 human lncRNAs.
Additionally, we found that the altered expression levels of miR-21, miR-155 and miR-101-3p were associated with forced vital capacity (FVC) and radiological features in IPF.
MicroRNA-21 was significantly upregulated in isolated lung epithelial cells during bleomycin-induced lung fibrosis and human idiopathic pulmonary fibrosis.
These findings suggest that serum miR-21 is associated with IPF and the degree of damage indicated by FVC and radiologic examinations could correlate with miR-21 and miR-155 expression in serum.
These experiments demonstrate an important role for miR-21 in fibrotic lung diseases and also suggest a novel approach using miRNA therapeutics in treating clinically refractory fibrotic diseases, such as IPF.