Bone marrow production of lung cells: The impact of G-CSF, cardiotoxin, graded doses of irradiation, and subpopulation phenotype

Abstract

Objective-Previous studies have demonstrated the production of various types of lung cells from marrow cells under diverse experimental conditions. Our aim was to identify some of the variables that influence conversion in the lung. Methods-In separate experiments, mice received various doses of total-body irradiation followed by transplantation with whole bone marrow or various subpopulations of marrow cells (Lin −/+ , ckit −/+ , Sca-1 −/+ ) from GFP + (C57BL/6-TgN[ACTbEGFP]1Osb) mice. Some were given intramuscular cardiotoxin and/or mobilized with granulocyte colony-stimulating factor (G-CSF).Results-The production of pulmonary epithelial cells from engrafted bone marrow was established utilizing green fluorescent protein (GFP) antibody labeling to rule out autofluorescence and deconvolution microscopy to establish the colocaliztion of GFP and cytokeratin and the absence of CD45 in lung samples after transplantation. More donor-derived lung cells (GFP + /CD45 − ) were seen with increasing doses of radiation (5.43% of all lung cells, 1200 cGy). In the 900-cGy group, 61.43% of GFP + /CD45 − cells were also cytokeratin + . Mobilization further increased GFP + / CD45 − cells to 7.88% in radiation-injured mice. Up to 1.67% of lung cells were GFP + /CD45 − in radiation-injured mice transplanted with Lin − , c-kit + , or Sca-1 + marrow cells. Lin + , c-kit − , and Sca-1 − subpopulations did not significantly engraft the lung. Conclusions-We have established that marrow cells are capable of producing pulmonary epithelial cells and identified radiation dose and G-CSF mobilization as variables influencing the production of lung cells from marrow cells. Furthermore, the putative lung cell-producing marrow cell has the phenotype of a hematopoietic stem cell.

Cellular Phenotype and Extracellular Vesicles: Basic and Clinical Considerations

“…In a similar vein, by studying murine lung originator cells and murine target marrow cells, Aliotta et al [28][29][30] showed that lung RNA was transferred to marrow cells inducing the expression of lung-specific mRNAs (surfactants A-D, Clara cell-specific protein, and aquaporin-5) and proteins and altering the function of marrow cells toward that of pulmonary cells. This later was shown by the increase in prosurfactantpositive pulmonary cells after transplant with vesicle exposed marrow.…”

“…These meaningless criteria nevertheless hurt the field and impaired progress. In our own studies, we had demonstrated that the engraftment of GFP + marrow cells into lethally irradiated mice resulted in the appearance of GFP + pulmonary epithelial cells in the lungs of transplanted mice [28]. Subsequent studies showed that when lung tissue was cultured opposite murine marrow cells, but separated from them by a cell impermeable 0.4 mm membrane, the marrow cells expressed the pulmonary-specific mRNAs, surfactants A-D, aquaporin-5, and Clara cellspecific protein [29].…”

Gene therapy approaches for stem cell protection

“…17 The administration of radiolabeled, trackable hematopoietic stem cells results in initial transient homing of these cells to the lung, then a secondary clearance from the lung, and migration to bone marrow sites. 24 Furthermore, initial lodging of engrafted hematopoietic cells to reticular/adventitial cell sites in the marrow sinuses is followed by secondary migration to sites of the true hematopoietic stem cell niche. 17 Increased mobilization of hematopoietic cells from the marrow into the circulation is known to increase following G-CSF, keratinocyte growth factor (KGF) or IL-11 administration.…”

“…12,[24][25][26] Toxicity to the non-hematopoietic organ microenvironment can facilitate engraftment or repopulation by cells from other organs including the marrow. 24,27,28 Exposure of the rat liver to carbon tetrachloride, followed by further damage to repopulating cells by 3-amino-fluorine alters the liver microenvironment to accept bone marrow-derived cells which are capable of differentiating into both hepatocytes and hepatic duct cells. 27 Irradiation and/or chemical injury to the stromal microenvironment of the heart, lung, esophagus and central nervous system also facilitates homing and differentiation of bone marrow-derived cells into functioning components of that organ.…”

“…27 Irradiation and/or chemical injury to the stromal microenvironment of the heart, lung, esophagus and central nervous system also facilitates homing and differentiation of bone marrow-derived cells into functioning components of that organ. 18,24 Embryonic stem cells have been substituted for bone marrow stem cells as progenitor populations in these Gene therapy stem cell protection JS Greenberger experiments, but toxicity to the recipient microenvironment limits their engraftment as well. 29 Gene therapy approaches to reduce oxidative stress effects on repopulating stem cells by the irradiated or injured organ microenvironment…”