TY - JOUR

T1 - Characterization of osteoclasts derived from CD14+ monocytes isolated from peripheral blood

AU - Sørensen, Mette Grøndahl

AU - Henriksen, Kim

AU - Schaller, Sophie

AU - Henriksen, Dennis Bang

AU - Nielsen, Finn Cilius

AU - Dziegiel, Morten Hanefeld

AU - Karsdal, Morten Asser

PY - 2007

Y1 - 2007

N2 - Bone resorption is solely mediated by osteoclasts. Therefore, a pure osteoclast population is of high interest for the investigation of biological aspects of the osteoclasts, such as the direct effect of growth factors and hormones, as well as for testing and characterizing inhibitors of bone resorption. We have established a pure, stable, and reproducible system for purification of human osteoclasts from peripheral blood. We isolated CD14-positive (CD14+) monocytes using anti-CD14-coated beads. After isolation, the monocytes are differentiated into mature osteoclasts by stimulation with macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappaB ligand (RANKL). Osteoclast formation was only observed in the CD14+ population, not in the CD14- population, and only in the presence of both M-CSF and RANKL, confirming that the CD14+ system is a pure population of osteoclast precursors. No expression of osteoclast markers was observed in the absence of RANKL, whereas RANKL dose-dependently induced the expression of cathepsin K, tartrate-resistant acid phosphatase (TRACP), and matrix metallo proteinase (MMP)-9. Furthermore, morphological characterization of the cells demonstrated that actin rings were only formed in the presence of RANKL. Moreover, the osteoclasts were capable of forming acidic resorption lacunae, and inhibitors of lysosomal acidification attenuated this process. Finally, we measured the response to known bone resorption inhibitors, and found that the osteoclasts were sensitive to these and thereby provided a robust and valid method for interpretation of the effect of antiresorptive compounds. In conclusion, we have established a robust assay for developing osteoclasts that can be used to study several biological aspects of the osteoclasts and which in combination with the resorption marker CTX-I provides a useful tool for evaluating osteoclast function in vitro.

AB - Bone resorption is solely mediated by osteoclasts. Therefore, a pure osteoclast population is of high interest for the investigation of biological aspects of the osteoclasts, such as the direct effect of growth factors and hormones, as well as for testing and characterizing inhibitors of bone resorption. We have established a pure, stable, and reproducible system for purification of human osteoclasts from peripheral blood. We isolated CD14-positive (CD14+) monocytes using anti-CD14-coated beads. After isolation, the monocytes are differentiated into mature osteoclasts by stimulation with macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappaB ligand (RANKL). Osteoclast formation was only observed in the CD14+ population, not in the CD14- population, and only in the presence of both M-CSF and RANKL, confirming that the CD14+ system is a pure population of osteoclast precursors. No expression of osteoclast markers was observed in the absence of RANKL, whereas RANKL dose-dependently induced the expression of cathepsin K, tartrate-resistant acid phosphatase (TRACP), and matrix metallo proteinase (MMP)-9. Furthermore, morphological characterization of the cells demonstrated that actin rings were only formed in the presence of RANKL. Moreover, the osteoclasts were capable of forming acidic resorption lacunae, and inhibitors of lysosomal acidification attenuated this process. Finally, we measured the response to known bone resorption inhibitors, and found that the osteoclasts were sensitive to these and thereby provided a robust and valid method for interpretation of the effect of antiresorptive compounds. In conclusion, we have established a robust assay for developing osteoclasts that can be used to study several biological aspects of the osteoclasts and which in combination with the resorption marker CTX-I provides a useful tool for evaluating osteoclast function in vitro.

KW - Animals

KW - Antigens, CD14

KW - Blood

KW - Cattle

KW - Cell Differentiation

KW - Female

KW - Humans

KW - Microarray Analysis

KW - Monocytes

KW - Osteoclasts

U2 - 10.1007/s00774-006-0725-9

DO - 10.1007/s00774-006-0725-9

M3 - Journal article

C2 - 17187192

VL - 25

SP - 36

EP - 45

JO - Journal of Bone and Mineral Metabolism

JF - Journal of Bone and Mineral Metabolism

SN - 0914-8779

IS - 1

ER -