Submit a Letter to the Editor
Abstract
The origin of fibroblasts in pulmonary fibrosis is assumed to be intrapulmonary, but their extrapulmonary origin and especially derivation from bone marrow (BM) progenitor cells has not been ruled out. To examine this possibility directly, adult mice were durably engrafted with BM isolated from transgenic mice expressing enhanced GFP. Induction of pulmonary fibrosis in such chimera mice by endotracheal bleomycin (BLM) injection caused large numbers of GFP+ cells to appear in active fibrotic lesions, while only a few GFP+ cells could be identified in control lungs. Flow-cytometric analysis of lung cells confirmed the BLM-induced increase in GFP+ cells in chimera mice and revealed a significant increase in GFP+ cells that also express type I collagen. GFP+ lung fibroblasts isolated from chimera mice expressed collagen and telomerase reverse transcriptase but not α-smooth muscle actin. Treatment of isolated GFP+ fibroblasts with TGF-β failed to induce myofibroblast differentiation. Cultured lung fibroblasts expressed the chemokine receptors CXCR4 and CCR7 and responded chemotactically to their cognate ligands, stromal cell–derived factor-1α and secondary lymphoid chemokine, respectively. Thus the collagen-producing lung fibroblasts in pulmonary fibrosis can also be derived from BM progenitor cells.
Authors
Naozumi Hashimoto, Hong Jin, Tianju Liu, Stephen W. Chensue, Sem H. Phan
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. We reserve the right to edit any letter for length, content, and clarity. Authors will be notified by e-mail if their letters were accepted. 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 editors@the-jci.org.
Copyright © 2021 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)