Evidence of Temporary Airway Epithelial Repopulation and Rare Clonal Formation by BM‐derived Cells Following Naphthalene Injury in Mice

Abstract

The goal of the study was to investigate participation of bone marrow (BM) cells in the process of airway epithelial restoration after naphthalene-induced injury. We transplanted sex-mismatched green fluorescent protein (GFP) -tagged BM-derived cultured plastic-adherent mesenchymal stem cells into 5Gy-irradiated C57BL/6 recipients. After 1 month of recovery, experimental animals were subjected to 250 mg/kg naphthalene IP. Animals were killed at 2-30 days after naphthalene. By immunofluorescence, immunohistochemistry, and by in situ hybridization for the Y-chromosome, we observed patches of donor-derived cells in the large and small conducting airways, mostly at 2-6 days after injury. GFP 1 cells in the epithelium of airways were positive for pancytokeratin and some other epithelial markers. Although rare, GFP 1 cells formed clear isolated patches of the bronchial epithelium, consistent with clonal formation; as some cells were also positive for proliferating cell nuclear antigen, a marker of proliferating cells. After day 12, only occasional GFP 1 cells were present in the epithelium. These data confirm that bone marrow-derived cultured mesenchymal cells can participate in the recovery of the injured airway epithelium after naphthalene-induced injury with minimal long-term engraftment.

Hematopoietic Stem/Progenitor Cells Express Functional Mitochondrial Energy-Dependent Cystic Fibrosis Transmembrane Conductance Regulator

“…However, in reports that provided evidence of engraftment and differentiation by systemic administration of BM-derived stem cells, the frequency in airways is very low ( < 1%). We and others [11,16] have delivered BM cells directly (by intratracheal instillation) to the lung after lung injury in mice, with results similar to the systemic administration route. Meanwhile, engraftment studies have been made also in CF mice.…”

“…In vivo studies in mouse models have suggested that bone marrow (BM)-derived hematopoietic stem/progenitor cells (HSPCs) can localize to the lung and acquire phenotypic markers of airway and alveolar epithelium, vascular endothelium, and interstitial cells [7][8][9][10][11]. There is also evidence that blood-borne stem cells may contribute to lung tissue in recipients of BM or lung transplantation [12][13][14].…”

Paracrine Effects and Heterogeneity of Marrow-Derived Stem/Progenitor Cells: Relevance for the Treatment of Respiratory Diseases

“…Since then, several studies have demonstrated the ability of marrow-derived hematopoietic stem/progenitor cells (HSPCs) to home to the lung and transform into epithelial cells [Krause et al, 2001;Grove et al, 2002;Theise et al, 2002;Abe et al, 2004;Serikov et al, 2007]. There is also evidence that bloodborne stem cells may contribute to lung tissue in recipients of bone marrow or lung transplantation [Kleeberger et al, 2003;Suratt et al, 2003;Mattsson et al, 2004].…”

Bone Marrow-Derived Cells Participate in Stromal Remodeling of the Lung Following Acute Bacterial Pneumonia in Mice

“…Previously, staining for Y chromosome [12] or for both Y and X chromosomes [28] was effectively used to determine the possibility of cell fusion. In this study we did not perform this analysis because we previously had shown that GFP is a reliable tag of engrafted cells by Y chromosome staining in sex-mismatched transplantations [23]; therefore, we checked only GFP-positive cells for polyploidy, which was not observed. Because we were not able to demonstrate physiologically important or long-term engraftment of bone marrow cells as specialized epithelial or endothelial cells, analysis of the possibility of cell fusion was not warranted.…”

“…In 5-Gy-irradiated chimeric mouse subjected to naphthalene-induced lung injury, we found very limited engraftment of bone marrow-derived mesenchymal stem cells in the bronchial epithelium [23], although in vitro these cells were capable of endodermal differentiation [24]. Homing of BMDC to the lung and their possible differentiation into specialized cells of endothelial or epithelial lining, as well as participation in postinflammatory lung fibrosis following acute bacterial pneumonia, have not yet been studied.…”