T. Yamane et al., DEVELOPMENT OF OSTEOCLASTS FROM EMBRYONIC STEM-CELLS THROUGH A PATHWAY THAT IS C-FMS BUT NOT C-KIT DEPENDENT, Blood, 90(9), 1997, pp. 3516-3523
Osteoclasts are hematopoietic cells essential for bone resorption, To
study the derivation of these interesting cells, we developed a stepwi
se culture system where stromal cells promote embryonic stem (ES) cell
s to differentiate into mature osteoclasts. Three phases to this diffe
rentiation process include (1) induction of hematopoiesis, along with
the generation of osteoclast precursors, (2) expansion of these precur
sors, and (3) terminal differentiation into mature osteoclasts in the
presence of 1 alpha, 25-dihydroxyvitamine D-3. Although the transition
of ES cells to the hematopoietic lineage was not blocked by an antibo
dy to c-fms, later phases were dependent on a signaling through this t
ransmembrane receptor as indicated by the finding that anti-c-fms-trea
tment of cells in the second and third phases reduced the number of os
teoclasts produced by 75% and more than 99%, respectively, Blockade of
signaling through another tyrosine kinase-type receptor, c-kit did no
t affect any stages of osteoclastogenesis, although generation of othe
r hemopoietic lineages was reduced to less than 10% of untreated. When
small numbers of ES cells were directly cultured under conditions tha
t promote osteoclast differentiation, tartrate-resistant acid phosphat
ase-positive multinucleated cells were observed at the edge but not in
side of colonies, This suggests that some types of cell-cell interacti
ons may inhibit development of mature osteoclasts. The culture system
developed here provides an important tool for osteoclast biology, (C)
1997 by The American Society of Hematology.