Retinoic acid induces osteoclast-like cell formation by directly acting on hemopoietic blast cells and stimulates osteopontin mRNA expression in isolated osteoclasts.
Although retinoic acid (RA) has been considered to be a bone-resorbing agent both in vivo and in vitro, its mechanism remains still unclear. The present study was performed to examine the effect of RA on osteoclast-like cell formation in the presence or absence of osteoblasts and to study whether RA would affect osteopontin mRNA expression in isolated rabbit osteoclasts. RA (10(-8) and 10(-6) M) significantly stimulated the formation of osteoclast-like cell in osteoblast-containing mouse bone cell cultures. Also, RA caused a stimulation of osteoclast-like cell formation from hemopoietic blast cells supported by granulocyte macrophage-colony stimulating factor (GM-CSF) in mouse spleen cell cultures. However, RA did not affect blast cell number in these cultures and significantly inhibited GM-CSF-stimulated proliferation of hemopoietic blast cells. On the other hand, RA stimulated the bone-resorbing activity of mature osteoclasts in mouse bone cell cultures. Moreover, RA caused a stimulation of osteopontin mRNA expression in isolated rabbit osteoclasts. The present study demonstrated for the first time that RA stimulated osteoclast-like cell formation, presumably through directly acting on the hemopoietic blast cells, and that RA stimulated osteopontin mRNA expression in isolated rabbit osteoclasts.
Kaji
H
H
Department of Medicine, Kobe University School of Medicine, Japan.
Sugimoto
T
T
Kanatani
M
M
Fukase
M
M
Kumegawa
M
M
Chihara
K
K
D000818:Animals; D001862:Bone Resorption / Q000378:metabolism; D002117:Calcitriol / Q000494:pharmacology; D002455:Cell Division; D002478:Cells, Cultured; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D010010:Osteoclasts / Q000166:cytology / Q000378:metabolism*; D053495:Osteopontin; D010750:Phosphoproteins / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis*; D011817:Rabbits; D012795:Sialoglycoproteins / Q000096:biosynthesis*; D013154:Spleen / Q000166:cytology; D014212:Tretinoin / Q000494:pharmacology*
D010750:Phosphoproteins; D012333:RNA, Messenger; D012795:Sialoglycoproteins; C506896:Spp1 protein, mouse; D053495:Osteopontin; D014212:Tretinoin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D002117:Calcitriol