BMP-4 of Xenopus laevis stimulates differentiation of human primary osteoblast-like cells

Since bone morphogenetic proteins (BMPs) are highly homologous, we investig ated the hypothesis that recombinant BMP-4 of the genome of Xenopus laevis (rxBMP-4) may influence the proliferation or differentiation of human prima ry osteoblast-like cells (HPOC), as occurs with recombinant human BMP (rhBM P-2). HPOC were incubated in the presence of either rxBMP-4, rhBMP-2 or basic fib roblast growth factor (rh-bFGF), The last two were used as positive control s and are known to induce differentiation or proliferation of HPOC, respect ively. rxBMP-4 (50 ng/ml and 100 ng/ml) induced a differentiation of HPOC to almos t the same extent as rhBMP-2, whereas the addition of rh-bFGF, applied in t he same concentration, failed to have any influence on cell differentiation . rh-bFGF however, provoked an increase in cell proliferation of up to 150% when compared with non-stimulated HPOC, while rhBMP-2 and rxBMP-4 had no s uch effect. Our results indicate an equipotent effect of rhBMP-2 and rxBMP-4 obtained f rom Xenopus laevis on the differentiation and proliferation of human primar y osteoblast-like cells.