MicroRNA-326 regulates profibrotic functions of transforming growth factor-β in pulmonary fibrosis

Sudipta Das, Manish Kumar, Vinny Negi, Bijay Pattnaik, Y. S. Prakash, Anurag Agrawal, Balaram Ghosh

Research output: Contribution to journalArticlepeer-review

106 Scopus citations


Idiopathic pulmonary fibrosis (IPF) is a fatal disorder resulting from the progressive remodeling of lungs, with no known effective treatment. Although transforming growth factor (TGF)-b has a wellestablished role in lung fibrosis, clinical experience with neutralizing antibodies to TGF-β has been disappointing, and strategies to directly suppress TGF-β1 secretion are needed. In this study we used a combination of in silico, in vitro, and in vivo approaches to identify microRNAs involved in TGF-β1 regulation and to validate the role of miR-326 in pulmonary fibrosis.We show that hsa-miR-326 regulates TGF-β1 expression and that hsa-miR-326 levels are inversely correlated to TGF-β1 protein levels in multiple human cell lines. The increase in TGF-β1 expression during the progression of bleomycin-induced lung fibrosis in mice was associated with loss of mmu-miR-326. Restoration of mmu-miR-326 levels by intranasal delivery of miR-326 mimics was sufficient to inhibit TGF-β1 expression and attenuate the fibrotic response. Moreover, human IPF lung specimens had markedly diminished miR-326 expression as compared with nonfibrotic lungs. Additional targets of miR-326 controlling TGF-β signaling and fibrosis-related pathways were identified, and miR-326 was found to down-regulate profibrotic genes, such as Ets1, Smad3, and matrix metalloproteinase 9, whereas it up-regulates antifibrotic genes, such as Smad7. Our results suggest for the first time that miR-326 plays a key role in regulating TGF-β1 expression and other profibrotic genes and could be useful in developing better therapeutic strategies for alleviating lung fibrosis.

Original languageEnglish (US)
Pages (from-to)882-892
Number of pages11
JournalAmerican journal of respiratory cell and molecular biology
Issue number5
StatePublished - May 2014


  • Idiopathic pulmonary fibrosis
  • MicroRNAs
  • Transforming growth factor-b signaling

ASJC Scopus subject areas

  • Molecular Biology
  • Pulmonary and Respiratory Medicine
  • Clinical Biochemistry
  • Cell Biology


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