[The roles of Smad 2/3 in transforming growth factor-beta 1 signaling in human dental pulp cells].
OBJECTIVE
To explore the roles of Smad 2/3 in transforming growth factor-beta(1) (TGF-beta(1)) signaling by human dental pulp cells.


METHODS
Laser scanning confocal microscope was used to observe translocation of Smad 2/3 from plasma into nucleus in cultured dental pulp cells at early stage of TGF-beta(1) treatment, and changes of Smad 2/3 protein expression at later stage were evaluated by Western blot analyses.


RESULTS
The expression of Smad 2/3 (fluorescence intensity) kept decreasing in cytoplasm but increasing in nucleus within 2 h after TGF-beta(1) treatment, forming a trend that Smad 2/3 translocated into nucleus from cytoplasma. The total amount of Smad 2 protein remained unchanged before and after TGF-beta(1) treatment, but the expression level of Smad 3 decreased markedly after 24 h treatment and kept dropping by 48 h.


CONCLUSIONS
The results suggest that the Smad 2/3 may be the downstream signal transducers of TGF-beta(1) in human dental pulp cells and Smad 2/3 may mediate TGF-beta(1) signaling by translocation early in TGF-beta(1) treatment, while down-regulation of Smad 3 expression by TGF-beta(1) at later stage is involved in negative modulation of TGF-beta(1) signaling.
Bao
Liu-yu
LY
Department of Operative Dentistry, College of Stomatology, The Fourth Military Medical University, Xi'an 710032, China.
Niu
Zhong-ying
ZY
Wang
Ping
P
D000293:Adolescent; D000328:Adult; D001692:Biological Transport / Q000187:drug effects; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D002648:Child; D003593:Cytoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism* / Q000502:physiology; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D018613:Microscopy, Confocal; D015398:Signal Transduction; D051899:Smad2 Protein; D051900:Smad3 Protein; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism* / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1
D004268:DNA-Binding Proteins; C497782:SMAD2 protein, human; C497790:SMAD3 protein, human; D051899:Smad2 Protein; D051900:Smad3 Protein; C508960:TGFB1 protein, human; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1