Suppressive effects of nicotine on the cytodifferentiation of murine periodontal ligament cells.
OBJECTIVE
Tobacco smoking has been suggested to be one of the important risk factors of developing periodontal disease. Although epidemiological studies have shown the detrimental effects of smoking on periodontal disease, the effects of smoke compounds on gingival tissue are not well understood. The aim of this study was to evaluate the effects of nicotine, which is the major component of the thousands of chemicals that constitute cigarette smoke, for cytodifferentiation of murine periodontal ligament (MPDL) cell.


METHODS
Expression of nAChR subunits on MPDL cells was examined using RT-PCR. The effects of nicotine on gene expression of extracellular matrices and osteoblastic transcription factors were evaluated by quantitative RT-PCR. Mineralized nodule formation of nicotine-treated MPDL cells was characterized by alizarin red staining.


RESULTS
Murine periodontal ligament cells expressed several subunits of nAChR, which have functional calcium signals in response to nicotine. Gene expression of extracellular matrices and osteoblastic transcription factors were reduced in nicotine-treated MPDL cells. In addition, mineralized nodule formation was inhibited in MPDL cells in the presence of nicotine.


CONCLUSIONS
Our findings indicate that nicotine may negatively regulate the cytodifferentiation and mineralization of MPDL cells.
Yanagita
M
M
Department of Periodontology, Division of Oral Biology and Disease Control, Osaka University Graduate School of Dentistry, Osaka, Japan.
Kojima
Y
Y
Kawahara
T
T
Kajikawa
T
T
Oohara
H
H
Takedachi
M
M
Yamada
S
S
Murakami
S
S
D000469:Alkaline Phosphatase / Q000187:drug effects; D000818:Animals; D002113:Calcification, Physiologic / Q000187:drug effects; D020013:Calcium Signaling / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002999:Clone Cells; D024042:Collagen Type I / Q000187:drug effects; D050659:Core Binding Factor Alpha 1 Subunit / Q000187:drug effects; D005109:Extracellular Matrix / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D010006:Osteoblasts / Q000187:drug effects; D053495:Osteopontin / Q000187:drug effects; D010513:Periodontal Ligament / Q000166:cytology / Q000187:drug effects*; D011978:Receptors, Nicotinic / Q000032:analysis; D000076182:Sp7 Transcription Factor; D014157:Transcription Factors / Q000187:drug effects; D016335:Zinc Fingers / Q000187:drug effects
D024042:Collagen Type I; D050659:Core Binding Factor Alpha 1 Subunit; D018722:Nicotinic Agonists; D011978:Receptors, Nicotinic; C493716:Runx2 protein, mouse; D000076182:Sp7 Transcription Factor; C479466:Sp7 protein, mouse; C506896:Spp1 protein, mouse; D014157:Transcription Factors; D053495:Osteopontin; D009538:Nicotine; D000469:Alkaline Phosphatase