Use of recombinant adeno-associated viral vectors as a tool for labeling bone marrow cells

We have tested the feasibility of using recombinant adeno-associated virus (rAAV) vectors as a tool for labeling bone marrow (BM) cells in vivo. We infected BM cells of donor FVB mice with rAAV vectors containing the lacZ gene for 2 h. We then injected the rAAV-infected cells to lethally irradiated-recipient FVB mice. Peripheral blood (PB), BM and spleen harvested at 4 weeks after BM transplant (BMT) demonstrated stable engraftment in β-galactosidase (β-gal) expression. In contrast, Dil-labeling displayed only a faint signal 4 weeks after BMT. To analyze the kinetics of BM cells, we injected vascular endothelial growth factor (VEGF), which promotes mobilization of BM cells. Administration of VEGF protein significantly increased the rAAV-mediated β-gal expression in PB and BM of recipient mice. Moreover, when myocardial infarction was induced in BMT mice, the ischemic area exhibited significant β-gal staining in rAAV-labeled BMT group. rAAV vectors programmed stable transduction in BM cells in vivo through rapid infection. rAAV appears to represent a useful vector for labeling BM cells ex vivo prior to BMT for analysis of cardiovascular therapeutic purposes.