Localization and expression of CSF-1 receptor in rat dental follicle cells.
Colony-stimulating factor-1 (CSF-1) accelerates tooth eruption in rats and is localized in the dental follicle, a loose connective tissue sac that is necessary for eruption to occur. CSF-1 enhances the cellular events that occur in the follicle prior to eruption--namely, an influx of monocytes into the follicle early post-natally to form the osteoclasts needed to resorb bone for the eruption pathway. Because CSF-1 levels are at a peak at day 3 post-natally, and because CSF-1 has an autocrine effect on its own gene expression, the question remains as to what causes the subsequent decline in CSF-1 protein and mRNA after day 3 post-natally. To determine if the autocrine effect is inhibited through the CSF-1 receptor, analysis of the CSF-1 receptor mRNA levels in cultured dental follicle cells reveals that high concentrations of CSF-1 reduce the gene expression of the CSF-1 receptor. Interleukin 1 alpha, a molecule that enhances CSF-1 gene expression, has no effect on CSF-1 receptor mRNA levels. Immunostaining for the CSF-1 receptor protein shows that it is present in the dental follicle early post-natally and is either absent or greatly reduced by day 10 post-natally. Earlier studies showed that the mRNA levels of the CSF-1 receptor also parallel this time course. Thus, the above results suggest that the feedback inhibition of the autocrine effect of CSF-1 on its own expression is through the effect of CSF-1 inhibiting the translation and transcription of its receptor. In turn, these molecular interactions possibly regulate the cellular events that occur in the follicle prior to and during eruption.
Wise
G E
GE
Department of Veterinary Anatomy and Cell Biology, School of Veterinary Medicine, Louisiana State University, Baton Rouge 70803-8408, USA.
Zhao
L
L
Grier
R L
RL
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D003795:Dental Sac / Q000276:immunology / Q000378:metabolism*; D015536:Down-Regulation; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D016173:Macrophage Colony-Stimulating Factor / Q000096:biosynthesis / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D016184:Receptors, Colony-Stimulating Factor / Q000032:analysis / Q000096:biosynthesis*; D014078:Tooth Eruption / Q000502:physiology*
D012333:RNA, Messenger; D016184:Receptors, Colony-Stimulating Factor; D016173:Macrophage Colony-Stimulating Factor