The roles of Smad 2/3 in transforming growth factor-beta 1 signaling in human dental pulp cells
Bao, L.-y.; Niu, Z.-y.; Wang, P.
Zhonghua Kou Qiang Yi Xue Za Zhi 38(1): 39-42
2003
ISSN/ISBN: 1002-0098 PMID: 12760775 Document Number: 562759
To explore the roles of Smad 2/3 in transforming growth factor-beta(1) (TGF-beta(1)) signaling by human dental pulp cells. 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. 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. 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.