Isolation and serum-free culture of epithelial cells derived from epithelial rests of Malassez in human periodontal ligament.
To study biological character and function of epithelial rests of Malassez (ERM) in human periodontal ligament, we have developed a serum-free culture system of epithelial cells (ME) derived from ERM. The mitogenic effects of fibroblast growth factor (FGF)-1, FGF-2, and FGF-7/keratinocyte growth factor (KGF) on ME, human periodontal ligament-derived fibroblasts (PLF), human oral epithelial cells (OE), and human submandibular gland-derived epithelial cells (SGE) were investigated under a serum-free culture condition. FGF-1 and FGF-7/KGF stimulated the growth of both ME and SGE but FGF-2 had no effect. On the other hand, FGF-1, FGF-2, and FGF-7/KGF increased the OE proliferation. These results suggested that the divergent requirement of FGF ligands among these cells would be attributed to the different expression pattern of FGF receptor (FGFR) messenger ribonucleic acid (mRNA) isotypes. Therefore, we examined the expression of FGFR isotypes in these cells. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of ME-and SGE-derived mRNAs revealed the presence of mRNA encoding FGFR2-IIIb, a high affinity receptor for FGF-1 and FGF-7/KGF. However, no mRNAs for other FGFR isotypes were detected in both ME and SGE. On the contrary, OE expressed FGFR1-IIIc, FGFR3-IIIb, and FGFR4 mRNAs as well as FGFR2-IIb. These results indicate that FGF binding sites on ME dominantly bind to FGF-1 and FGF-7/KGF, which transduce their signals via FGFR2-IIIb. Immunohistochemical analysis, PCR-Southern, ribonuclease protection assay (RPA), and Western blotting revealed that PLF expressed FGF-7/KGF mRNA and its peptide. These observations suggest that FGF-7/KGF might mediate epithelial-mesenchymal interactions between ME and PLF to maintain normal structure and function of periodontal ligament.
Yamanaka
T
T
Department of Molecular Oral Medicine and Maxillofacial Surgery I, Hiroshima University Faculty of Dentistry, Japan.
Sakamoto
A
A
Tanaka
Y
Y
Zhang
Y
Y
Hayashido
Y
Y
Toratani
S
S
Akagawa
Y
Y
Okamoto
T
T
D015139:Blotting, Southern / Q000379:methods; D018929:Cell Culture Techniques / Q000379:methods; D002455:Cell Division / Q000187:drug effects; D002469:Cell Separation; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D016895:Culture Media, Serum-Free; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D016220:Fibroblast Growth Factor 1; D051526:Fibroblast Growth Factor 10; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D015870:Gene Expression; D006133:Growth Substances / Q000235:genetics / Q000494:pharmacology; D006801:Humans; D010513:Periodontal Ligament / Q000166:cytology*; D011505:Protein-Tyrosine Kinases; D012333:RNA, Messenger; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics; D051496:Receptor, Fibroblast Growth Factor, Type 1; D051497:Receptor, Fibroblast Growth Factor, Type 2; D051498:Receptor, Fibroblast Growth Factor, Type 3; D051499:Receptor, Fibroblast Growth Factor, Type 4; D017468:Receptors, Fibroblast Growth Factor / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013363:Submandibular Gland / Q000166:cytology
D017077:Culture Media, Conditioned; D016895:Culture Media, Serum-Free; C496453:FGF7 protein, human; D051526:Fibroblast Growth Factor 10; D006133:Growth Substances; D012333:RNA, Messenger; D017468:Receptors, Fibroblast Growth Factor; D016222:Fibroblast Growth Factor 2; D016220:Fibroblast Growth Factor 1; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors; C496348:FGFR1 protein, human; C496353:FGFR2 protein, human; C496365:FGFR3 protein, human; C496371:FGFR4 protein, human; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1; D051497:Receptor, Fibroblast Growth Factor, Type 2; D051498:Receptor, Fibroblast Growth Factor, Type 3; D051499:Receptor, Fibroblast Growth Factor, Type 4