The roles of Smad 2/3 in transforming growth factor-beta 1 signaling in human dental pulp cells / 中华口腔医学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To explore the roles of Smad 2/3 in transforming growth factor-beta(1) (TGF-beta(1)) signaling by human dental pulp cells.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>