Idiopathic pulmonary fibrosis (IPF) is a deadly disease with a poor prognosis and few treatment options. Pathological remodeling of the extracellular matrix (ECM) is a key factor that drives the disease pathogenesis, although the underlying mechanisms remain unknown. Alternative polyadenylation (APA) has recently been shown to play a major role in cellular responses to stress by driving the expression of fibrotic factors through the alteration of miRNA sensitivity, but a connection to IPF has not been established. Here, we demonstrated that CFIm25, a global regulator of APA, was downregulated in the lungs of patients with IPF and mice with pulmonary fibrosis, with its expression selectively reduced in α–smooth muscle actin–positive (α-SMA–positive) fibroblasts. Following CFIm25 knockdown in healthy human lung fibroblasts, we identified 808 genes with shortened 3′-UTRs, including those involved in the TGF-β signaling pathway, the Wnt signaling pathway, and cancer pathways. The expression of key profibrotic factors was suppressed by CFIm25 overexpression in IPF fibroblasts. Finally, we demonstrated that deletion of CFIm25 in fibroblasts or myofibroblast precursors using either the Col1a1 or the Foxd1 promoter enhanced pulmonary fibrosis after bleomycin exposure. Collectively, our results identified CFIm25 downregulation as an important mechanism for elevating profibrotic gene expression in pulmonary fibrosis.
Tingting Weng, Junsuk Ko, Chioniso P. Masamha, Zheng Xia, Yu Xiang, Ning-yuan Chen, Jose G. Molina, Scott Collum, Tinne C. Mertens, Fayong Luo, Kemly Philip, Jonathan Davies, Jingjing Huang, Cory Wilson, Rajarajan A. Thandavarayan, Brian A. Bruckner, Soma S.K. Jyothula, Kelly A. Volcik, Lei Li, Leng Han, Wei Li, Shervin Assassi, Harry Karmouty-Quintana, Eric J. Wagner, Michael R. Blackburn
Guidelines: The Editorial Board will only consider letters that we deem relevant and of interest to our readers. We will not post data that have not been subjected to peer review, nor will we post letters that are essentially a reiteration of another letter. All accepted letters will be posted on our website within one week of acceptance. We reserve the right to edit any letter for length, content, and clarity. Authors of all accepted letters will be asked to preview any changes. Authors will be notified by e-mail if their letters were not accepted. As this is a final decision, no appeals will be considered.
Specific requirements: All letters must be 400 words or fewer. You may enter the letter as plain text or HTML. The author's name and e-mail address are required, and will be posted with the letter. All possible conflicts of interest must be noted, even if they are not posted. If you wish to include a figure (keep in mind that non-peer-reviewed data will not be posted), please contact the editors directly at firstname.lastname@example.org.