Establishment of bone marrow-derived endothelial cell lines from ts-SV40 T-antigen gene transgenic rats

Purpose. Postneonatal neovascularization is thought to result exclusively f rom the proliferation, migration, and remodeling of fully differentiated en dothelial cells (ECs). Recently, it has been reported that bone marrow cont ains cells which can differentiate into ECs and contribute to neoangiogenes is in adult species. In this study, we tried to establish conditionally imm ortalized endothelial cell lines (TR-BME) derived from rat bone marrow. Methods. Mononuclear cells were isolated and differentiated into ECs at 37 degreesC from the bone marrow of a transgenic rat harboring temperature-sen sitive SV40 large T-antigen (ts T-Ag) gene. Then, the cells were transferre d and incubated at 33 degreesC, a permissive temperature for ts T-Ag. Expre ssion of vascular endothelial growth factor (VEGF) receptor (VEGFR)-1, 2, T ie-1, 2 and von Willebrand factor (VWF) were assayed by reverse transcripta se-mediated polymerase chain reaction (RT-PCR). Results. We have established three cell lines incorporating 1,1'-dioctadecy l-3,3,3',3-tetramethylindo-carbocyanine perchlorate (DiI-Ac-LDL) with a spi ndle shape. One of these, clone 2, strongly ex pressed VEGFR-2, and weakly expressed VEGFR-1 and VWF. In contrast, clone 8 showed strong expression of Tie-1, 2, and VWF, and weak expression of VEGFR-1,2. All markers were expr essed strongly in clone 3. Conclusions. These data confirm that the above three TR-BME cells are novel ECs derived from bone marrow progenitors.