A body of work in the literature has shown that after marrow transplantation into irradiated mice, there appear cells in the lung with an epithelial lung cell phenotype, but with markers of the donor marrow cells. After transplantation of green-fluorescent protein positive marrow cells into lethally irradiated mice, we have previously shown that there are from 3–5% non-hematopoietic cells bearing the donor marrow markers in the lung, most of these being cytokeratin positive (

Aliotta et al.,
Exp Hematol.
,
34
(2):
230
–41,
2006
). We have utilized a cell impermeable double culture chamber to co-culture irradiated and non-irradiated lung across from marrow cells. With 2 or 7 days of co-culture, the marrow cells express the lung-specific mRNAs surfactant proteins B and C and Clara Cell specific protein at high levels. This phenomenon is most pronounced when the lung has been exposed to 500 cGy 5 days prior to initiating co-culture, although it is also seen with non-irradiated lung. Conditioned media from lung exerts the same effects and RNase treatment of the conditioned media markedly decreased this effect. Ultracentrifugation of the conditioned media pellets the converting activity, which appears to reside in microvesicles. These microvesicles were demonstrated to enter marrow stem cells and to enhance their capacity to convert to lung epithelial cells after transplantation. Most recently, we have also shown that the capacity to enter marrow cells varies both with the cell cycle status of lineage negative Sca-1+ murine marrow cells and with the source of the microvesicles, either from irradiated or normal lung. Altogether, these data indicate that microvesicle transfer from damaged tissue may be the basis of some forms of marrow plasticity, which have been previously reported.

Topics:
bone marrow transplantation, chemical surfactants, coculture techniques, culture media, conditioned, cytokeratin positive, endoribonucleases, information sharing, lung, pancreatic ribonuclease, pulmonary surfactants

Author notes

Disclosure: No relevant conflicts of interest to declare.

2007, The American Society of Hematology
2007
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