Transforming growth factor-beta1 autocrine stimulation regulates fibroblast proliferation in hereditary gingival fibromatosis.
BACKGROUND
Hereditary gingival fibromatosis (HGF) is a rare oral disease characterized by a slow and progressive enlargement of both the maxilla and mandible gingiva. Increased proliferation, elevated synthesis of extracellular matrix, particularly collagen, and reduced levels of matrix metalloproteinases seem to contribute to the pathogenesis of gingival overgrowth in HGF patients. Transforming growth factor-beta1 (TGF-beta1) is an important cytokine thought to play a major role in fibrotic disorders such as HGF due to its ability to stimulate the synthesis and reduce the degradation of extracellular matrix. In HGF fibroblasts, TGF-beta1 autocrine stimulation reduces expression and production of matrix metalloproteinases. However, the role of TGF-beta1 in fibroblast growth modulation has not been established in this disease.


METHODS
The aim of this study was to confirm the increased proliferation rate of HGF fibroblast cell lines and to explore a possible autocrine role of TGF-beta1 as a cell growth stimulator by blocking production of this endogenous cytokine using 2 well-established systems: antisense oligonucleotides and neutralizing antibodies.


RESULTS
Four different cellular proliferation assays, bromodeoxyuridine labeling, argyrophilic nucleolar organizing region staining, proliferating cell nuclear antigen, and mitotic indexes, confirmed that fibroblasts from HGF proliferate significantly faster than those from normal gingiva. Antisense oligonucleotides reduced TGF-beta1 production as demonstrated by capture enzyme-linked immunosorbent assay, whereas TGF-beta1 expression levels were not significantly modified. Blocking TGF-beta1 synthesis with oligonucleotides or its activity with specific antibodies resulted in a decreased magnitude of HGF fibroblast proliferation.


CONCLUSIONS
These results are consistent with the existence of an autocrine role of TGF-beta1 as a stimulator of HGF fibroblast proliferation.
de Andrade
C R
CR
University of Campinas Dental School, Piracicaba, São Paulo, Brazil.
Cotrin
P
P
Graner
E
E
Almeida
O P
OP
Sauk
J J
JJ
Coletta
R D
RD
D000328:Adult; D000704:Analysis of Variance; D000906:Antibodies; D019898:Autocrine Communication / Q000502:physiology; D001973:Bromodeoxyuridine / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D005351:Fibromatosis, Gingival / Q000235:genetics / Q000503:physiopathology*; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D005881:Gingiva / Q000166:cytology / Q000187:drug effects* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008940:Mitotic Index; D009697:Nucleolus Organizer Region / Q000473:pathology; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D018809:Proliferating Cell Nuclear Antigen / Q000096:biosynthesis; D014176:Protein Biosynthesis / Q000187:drug effects; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000494:pharmacology* / Q000502:physiology
D000906:Antibodies; D016376:Oligonucleotides, Antisense; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D001973:Bromodeoxyuridine