Estradiol and raloxifene decrease the formation of multinucleate cells in human bone marrow cultures.
Estrogen (E2) deficiency is responsible for increased bone turnover in the postmenopausal period, and it can be prevented by estrogen replacement therapy. The way estrogen acts on bone cells is not fully understood. Human bone marrow cell cultures may be a reliable model for studying the action of steroids on osteoclastogenesis in vitro. We examine the effects of estradiol and Raloxifene, a selective estrogen receptor modulator, on human primary bone marrow cells cultured for 15 days. 17beta-estradiol and Raloxifene significantly decreased the number of tartrate-resistant acid phosphatase multinucleate cells from osteoclast precursors on day 15. Estrogen receptor alpha (ER-alpha) mRNA was present in bone marrow mononuclear cells cultured for 5 days, but there was no estrogen receptor beta (ER-beta) mRNA, suggesting that this effect was mediated by ER-alpha. 15-day cultures no longer contained ER-alpha mRNA, suggesting that estrogen acts on early events of osteoclast differentiation. Finally, 10-8 M 17beta-estradiol has no effect on the release of IL-6 and IL-6-sr into the medium of marrow mononuclear cells cultured for 5 or 15 days. Osteoclast apoptosis was not affected by estradiol or Raloxifene after 15 days of culture under our conditions. In conclusion, we have shown that both estradiol and Raloxifene inhibit osteoclast differentiation in human bone marrow mononuclear cultures. The biological effect that can mimic in vivo differentiation could be mediated through ER-alpha.
Ramalho
Ana Claudia
AC
INSERM U. 349, Lariboisière Hospital, 2, rue Ambroise-Paré, 75475 Paris Cedex 10 France.
Couttet
Philippe
P
Baudoin
Claude
C
Morieux
Caroline
C
Graulet
Anne-Marie
AM
de Vernejoul
Marie-Christine
MC
Cohen-Solal
Martine E
ME
D017209:Apoptosis / Q000502:physiology; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects*; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D004958:Estradiol / Q000494:pharmacology*; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects*; D012333:RNA, Messenger / Q000096:biosynthesis; D020849:Raloxifene Hydrochloride / Q000494:pharmacology*; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism*; D018123:Receptors, Interleukin; D019947:Receptors, Interleukin-6; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020845:Selective Estrogen Receptor Modulators / Q000494:pharmacology; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D015850:Interleukin-6; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D018123:Receptors, Interleukin; D019947:Receptors, Interleukin-6; D011993:Recombinant Fusion Proteins; D020845:Selective Estrogen Receptor Modulators; C104543:interleukin 6-interleukin 6 receptor fusion protein, recombinant; D020849:Raloxifene Hydrochloride; D004958:Estradiol