Effects of sodium fluoride on the actin cytoskeleton of murine ameloblasts.
Fluoride is associated with a decrease in the incidence of dental caries, but excess fluoride can lead to enamel fluorosis, a defect that occurs during tooth enamel formation. In fibroblasts, the Arhgap gene encodes a RhoGAP, which regulates the small G protein designated RhoA. Fluoride treatment of fibroblasts inactivates RhoGAP, thereby activating RhoA, which leads to elevation of filamentous actin (F-actin). Since RhoA is a molecular switch, our hypothesis is that in ameloblasts, fluoride may alter the cytoskeleton through interference with the Rho signaling pathway. Our objective was to measure the effects of sodium fluoride on F-actin using tooth organ culture and confocal microscopy. The results indicated that cellular responses to fluoride include elevation of F-actin in ameloblasts. It was concluded from immunohistochemistry, RT-PCR and confocal approaches that the components of the Rho pathway are present in ameloblasts, and that the response to fluoride involves the Rho/ROCK pathway.
Li
Yong
Y
Department of Anatomy and Cell Biology, University of Pennsylvania School of Dental Medicine, Philadelphia, 19104-6030, USA.
Decker
Sylvia
S
Yuan
Zhi-An
ZA
Denbesten
Pamela K
PK
Aragon
Melissa A
MA
Jordan-Sciutto
Kelly
K
Abrams
William R
WR
Huh
Jung
J
McDonald
Celeste
C
Chen
Enhong
E
MacDougall
Mary
M
Gibson
Carolyn W
CW
D000199:Actins / Q000032:analysis / Q000187:drug effects*; D000565:Ameloblasts / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002327:Cariostatic Agents / Q000494:pharmacology*; D003599:Cytoskeleton / Q000187:drug effects*; D020690:GTPase-Activating Proteins / Q000235:genetics; D015870:Gene Expression / Q000187:drug effects; D007150:Immunohistochemistry / Q000379:methods; D051379:Mice; D018613:Microscopy, Confocal / Q000379:methods; D023421:Models, Animal; D008963:Molar / Q000378:metabolism; D009924:Organ Culture Techniques; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D012965:Sodium Chloride / Q000494:pharmacology; D012969:Sodium Fluoride / Q000494:pharmacology*; D020742:rhoA GTP-Binding Protein / Q000235:genetics
C109971:ARHGAP6 protein, human; D000199:Actins; D002327:Cariostatic Agents; D020690:GTPase-Activating Proteins; D012965:Sodium Chloride; D012969:Sodium Fluoride; D020742:rhoA GTP-Binding Protein