The effect of enamel matrix protein derivative on follicle cells in vitro.
BACKGROUND
It is thought that during development of the periodontium, dental follicle cells, when appropriately triggered, have the ability to differentiate into periodontal ligament fibroblasts, cementoblasts, and osteoblasts. However, the exact mechanisms/factors responsible for initiating cell differentiation are not defined. The purpose of this in vitro study was to further characterize follicle cells and to determine the effects of an enamel matrix-derived protein (EMD) on these cells.


METHODS
Murine follicle cells, transformed with simian virus 40 (SV 40) T antigen-containing virus (SVF cells), were used. SVF cells were cultured in Dulbecco's modified Eagle's medium (DMEM) plus 2% fetal bovine serum (FBS) or 2% FBS plus EMD (100 microg/ml), with and without ascorbic acid (50 microg/ml). For proliferation assays, cells were plated at 500 cells/cm2 in 24-well plates and counted on days 3, 4, and 5. For Northern analysis, total RNA was isolated on days 8, 12, and 18. Induction of mineral nodules by SVF cells was determined by von Kossa staining.


RESULTS
EMD had a significant proliferative effect on SVF cells, when compared with 2% FBS control. Based on investigations in situ, follicle cells at the time point used here do not express key mineral-associated markers, e.g., osteocalcin (OCN) or bone sialoprotein (BSP). Significantly, by day 12 in culture, Northern analysis indicated that the follicle cells expressed transcripts for BSP, OCN, and osteopontin (OPN). EMD increased OPN mRNA and decreased OCN mRNA expression. SVF cells were capable of inducing mineralization on day 18, but EMD blocked this activity.


CONCLUSIONS
These results suggest the follicle cells have the capacity to act as cementoblasts or osteoblasts. Furthermore, EMD can regulate follicle cell activity, thus suggesting that epithelial-mesenchymal interactions may be important during development of periodontal tissues.
Hakki
S S
SS
Department of Periodontics/Prevention/Geriatrics, University of Michigan, School of Dentistry, Ann Arbor 48109-1078, USA.
Berry
J E
JE
Somerman
M J
MJ
D000704:Analysis of Variance; D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000276:immunology; D015152:Blotting, Northern; D002113:Calcification, Physiologic / Q000187:drug effects; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002461:Cell Line, Transformed; D048429:Cell Size / Q000187:drug effects; D004396:Coloring Agents; D003739:Dental Cementum / Q000166:cytology; D003746:Dental Enamel Proteins / Q000494:pharmacology*; D003795:Dental Sac / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology; D058574:Integrin-Binding Sialoprotein; D051379:Mice; D010006:Osteoblasts / Q000166:cytology; D015675:Osteocalcin / Q000032:analysis; D053495:Osteopontin; D010750:Phosphoproteins / Q000032:analysis; D012795:Sialoglycoproteins / Q000032:analysis; D013539:Simian virus 40 / Q000276:immunology; D013223:Statistics as Topic
D000952:Antigens, Polyomavirus Transforming; D004396:Coloring Agents; D003746:Dental Enamel Proteins; C546872:Ibsp protein, mouse; D058574:Integrin-Binding Sialoprotein; D010750:Phosphoproteins; D012795:Sialoglycoproteins; C506896:Spp1 protein, mouse; C109069:enamel matrix proteins; D015675:Osteocalcin; D053495:Osteopontin