Hematopoietic mobilization in mice increases the presence of bone marrow-derived hepatocytes via in vivo cell fusion.
The mechanisms for in vivo production of bone marrow-derived hepatocytes (BMDHs) remain largely unclear. We investigated whether granulocyte colony-stimulating factor (G-CSF)-mediated mobilization of hematopoietic cells increases the phenomenon. Recurrent liver injury in mice expressing green fluorescent protein (EGFP) in all hematopoietic-derived cells was produced by 3 months of carbon tetrachloride (CCL4) injections. Histologically, there were necrotic foci with histiocyte-rich infiltrates, but little oval cell proliferation. Subsequently, some animals were mobilized with G-CSF for 1, 2, or 3 weeks. Animals were sacrificed 1 month after growth factor treatment. BMDH percentages were lower than previously reported, though G-CSF mobilization significantly augmented BMDH production in injured livers. BMDHs originating from in vivo fusion were evaluated by transplanting female EGFP+ cells into male mice. Binucleated, EGFP+ hepatocytes with one Y chromosome, indicating fusion, were identified. In conclusion, (1) mobilization of hematopoietic cells increases BMDH production and (2) as with the FAH-null model, the first model demonstrating hematopoietic/hepatocyte fusion, recurring CCl4-induced injury has macrophage-rich infiltrates, a blunted oval cell response, and a predominantly in vivo fusion process for circulating cell engraftment into the liver. These findings open the possibility of using hematopoietic growth factors to treat nonhematopoietic degenerative diseases.
Quintana-Bustamante
Oscar
O
Hematopoietic Gene Therapy Division, CIEMAT/M, Botín Foundation, Madrid, Spain.
Alvarez-Barrientos
Alberto
A
Kofman
Alexander V
AV
Fabregat
Isabel
I
Bueren
Juan A
JA
Theise
Neil D
ND
Segovia
José C
JC
D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology*; D002251:Carbon Tetrachloride / Q000633:toxicity; D002459:Cell Fusion; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D019650:Hematopoietic Stem Cell Mobilization; D022781:Hepatocytes / Q000502:physiology*; D017493:Leukocyte Common Antigens / Q000032:analysis; D008115:Liver Regeneration; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA
D016179:Granulocyte Colony-Stimulating Factor; D002251:Carbon Tetrachloride; D017493:Leukocyte Common Antigens