Identification of a bone marrow–derived epithelial-like population capable of repopulating injured mouse airway epithelium
Amy P. Wong, … , Jim Hu, Thomas K. Waddell
Amy P. Wong, … , Jim Hu, Thomas K. Waddell
Published January 26, 2009
Citation Information: J Clin Invest. 2009;119(2):336-348. https://doi.org/10.1172/JCI36882.
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Research Article Pulmonology

Identification of a bone marrow–derived epithelial-like population capable of repopulating injured mouse airway epithelium

Abstract

The bone marrow compartment is enriched in stem and progenitor cells, and an unidentified subpopulation of these cells can contribute to lung epithelial repair. Here we identify this subpopulation and quantitate its relative contribution to injured airway epithelium. A subpopulation of adherent human and murine bone marrow cells that expresses Clara cell secretory protein (CCSP) was identified using flow cytometry. When cultured at the air-liquid interface in ex vivo cultures, Ccsp+ cells expressed type I and type II alveolar markers as well as basal cell markers and active epithelial sodium channels. Ccsp+ cells preferentially homed to naphthalene-damaged airways when delivered transtracheally or intravenously, with the former being more efficient than the latter. Interestingly, naphthalene-induced lung damage transiently increased Ccsp expression in bone marrow and peripheral circulation. Furthermore, lethally irradiated Ccsp-null mice that received tagged wild-type bone marrow contained donor-derived epithelium in both normal and naphthalene-damaged airways. This study therefore identifies what we believe to be a newly discovered cell in the bone marrow that might have airway reconstitution potential in the context of cell-based therapies for lung disease. Additionally, these data could reconcile previous controversies regarding the contribution of bone marrow to lung regeneration.

Authors

Amy P. Wong, Armand Keating, Wei-Yang Lu, Pascal Duchesneau, Xinghua Wang, Adrian Sacher, Jim Hu, Thomas K. Waddell

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Figure 2

Characterization of the Ccsp+ BMC population.

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Characterization of the Ccsp+ BMC population. (A) Morphologically, C...
(A) Morphologically, Ccsp+ and Ccsp– cells were distinguishable in vitro. Ccsp+ cells were smaller, rounder cells, while Ccsp– cells were larger, with more cytoplasmic extensions. Ccsp+ cells expressed pan-hematopoietic marker CD45 and progenitor marker CD34. Both Ccsp+ and Ccsp– cells expressed the MSC markers CD73, CD90, and CD105. (B) Ccsp+ cells did not express the MSC markers CD106, type I collagen, or type IV collagen. Some Ccsp– cells expressed CD106, type IV collagen, and type I collagen. Insets are representative isotype staining controls. (C) Real-time PCR showed gene expression of some MSC markers (CD90, CD105, CD73) in Ccsp+ cells but not CD106. Hematopoietic genes CD45 and CD34 were also detected in Ccsp+ cells. Conversely, Ccsp– cells expressed all mesenchymal stromal cell genes but no hematopoietic genes. GAPDH was used as housekeeping gene for normalization of expression levels. Each bar represents normalized relative levels compared with MSCs (bone marrow nonadherent cells for CD45 and CD34). n = 4 sets of cells from 4 different animals. (D) Most Ccsp+ cells coexpressed both hematopoietic (CD45) and mesenchymal markers (CD90 and CD105). Control staining with CD45-PE (red) and secondary antibody specific for CD90/CD105 showed no cross-reactivity of the secondary antibody binding to CD45 primary antibody (no fluorescence in the green channel). Mixed isotypes were used as a control for nonspecificity of the primary antibody (inset). Hoechst counterstain was used to visualize nuclei (blue). All scale bars: 20 μm. Original magnification, ×20.