Osteoclasts and macrophages share progenitors that must receive decisive lineage signals driving them into their respective differentiation routes. Macrophage colony stimulation factor M-CSF is a common factor; bone is likely the stimulus for osteoclast differentiation. To elucidate the effects of both, shared mouse bone marrow precursor myeloid blast was precultured with M-CSF on plastic and on bone. M-CSF priming prior to stimulation with M-CSF and osteoclast differentiation factor RANKL resulted in a complete loss of osteoclastogenic potential without bone. Such M-CSF primed cells expressed the receptor RANK, but lacked the crucial osteoclastogenic transcription factor NFATc1. This coincided with a steeply decreased expression of osteoclast genes TRACP and DC-STAMP, but an increased expression of the macrophage markers F4/80 and CD11b. Compellingly, M-CSF priming on bone accelerated the osteoclastogenic potential: M-CSF primed cells that had received only one day M-CSF and RANKL and were grown on bone already expressed an array of genes that are associated with osteoclast differentiation and these cells differentiated into osteoclasts within 2 days. Osteoclastogenesis-insensitive precursors grown in the absence of bone regained their osteoclastogenic potential when transferred to bone. This implies that adhesion to bone dictates the fate of osteoclast precursors. Common macrophage-osteoclast precursors may become insensitive to differentiate into osteoclasts and regain osteoclastogenesis when bound to bone or when in the vicinity of bone.

dx.doi.org/10.1002/jcp.24702, hdl.handle.net/1765/84729
Journal of Cellular Physiology
Department of Immunology

de Vries, T.J, Schoenmaker, T, Aerts, D, Grevers, L.C, Souza, P.P, Nazmi, K, … Everts, V. (2015). M-CSF priming of osteoclast precursors can cause osteoclastogenesis-insensitivity, which can be prevented and overcome on bone. Journal of Cellular Physiology, 230(1), 210–225. doi:10.1002/jcp.24702