TGF-β2 and TGF-β1 differentially regulate the odontogenic and osteogenic differentiation of mesenchymal stem cells

To explore the effects of transforming growth factor-β2 (TGF-β2) and TGF-β1 on the odontogenic and osteogenic differentiation of mesenchymal stem cells (MSCs).

We used lentiviral transduction to knock down TGF-β1 or TGF-β2 in stem cells from dental apical papilla (SCAPs), and to generate bone marrow mesenchymal stem cells (BMSCs) with overexpression of TGF-β1 or TGF-β2. We investigated the odontogenic and osteogenic differentiation abilities of these transductants in vitro and in vivo.

In vitro, TGF-β2 knockdown in SCAPs reduced the expression of odontoblast-related markers DSPP and DMP-1, and increased the expression of osteoblast-related markers OCN and RUNX-2. Conversely, TGF-β1 knockdown had the opposite effects. TGF-β2 overexpression promoted expression of odontoblast-related markers in BMSCs at early differentiation, but inhibited the expression of odontoblast-related markers at later stages. TGF-β2 overexpression attenuated expression of osteogenic-related markers in BMSCs, while TGF-β1 overexpression enhanced odontoblast-related and osteoblast-related markers. SCAP or BMSC transductants were transplanted underneath kidneys in vivo. Masson staining showed that knockdown of TGF-β1, but not TGF-β2 promoted the expression of type I collagen in SCAPs. Immunohistochemical staining showed that TGF-β2 knockdown inhibited DSPP expression in SCAPs, but TGF-β1 knockdown had no obvious effect on DSPP expression. In vivo, TGF-β1 overexpression and TGF-β2 overexpression had no effect on the expression of type I collagen and DSPP in BMSCs.

TGF-β2 promotes odontogenic differentiation of SCAPs and attenuates osteogenic differentiation of SCAPs and BMSCs. TGF-β1 promotes osteogenic differentiation of BMSCs and plays a complex role in regulating odontogenic differentiation of MSCs.