Effects of Modulation of the Hedgehog and Notch Signaling Pathways on Osteoblast Differentiation Induced by Titanium with Nanotopography

by Selleckchem | Apr 15 2023

Background: The events of bone formation and osteoblast/titanium (Ti) interactions may be affected by Hedgehog and Notch signalling pathways. Herein, we investigated the effects of modulation of these signalling pathways on osteoblast differentiation caused by the nanostructured Ti (Ti-Nano) generated by H2SO4/H2O2.

Methods: Osteoblasts from newborn rat calvariae were cultured on Ti-Control and Ti-Nano in the presence of the Hedgehog agonist purmorphamine or antagonist cyclopamine and of the Notch antagonist N-(3,5-Difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) or agonist bexarotene. Osteoblast differentiation was evaluated by alkaline phosphatase activity and mineralization, and the expression of Hedgehog and Notch receptors was also evaluated.

Results: In general, purmorphamine and DAPT increased while cyclopamine and bexarotene decreased osteoblast differentiation and regulated the receptor expression on both Ti surfaces, with more prominent effects on Ti-Nano. The purmorphamine and DAPT combination exhibited synergistic effects on osteoblast differentiation that was more intense on Ti-Nano.

Conclusion: Our results indicated that the Hedgehog and Notch signalling pathways drive osteoblast/Ti interactions more intensely on nanotopography. We also demonstrated that combining Hedgehog activation with Notch inhibition exhibits synergistic effects on osteoblast differentiation, especially on Ti-Nano. The uncovering of these cellular mechanisms contributes to create strategies to control the process of osseointegration based on the development of nanostructured surfaces.

Comments：

In this study, the effects of Hedgehog and Notch signalling pathways on osteoblast differentiation and their interaction with nanostructured titanium (Ti-Nano) were investigated. Osteoblasts were cultured on Ti-Nano and Ti-Control in the presence of Hedgehog agonist purmorphamine or antagonist cyclopamine and Notch antagonist DAPT or agonist bexarotene. Osteoblast differentiation was evaluated by alkaline phosphatase activity and mineralization, and the expression of Hedgehog and Notch receptors was also evaluated.

The results showed that the activation of Hedgehog pathway with purmorphamine and inhibition of Notch pathway with DAPT increased osteoblast differentiation and regulated receptor expression on both Ti surfaces, with more significant effects on Ti-Nano. Conversely, inhibition of Hedgehog pathway with cyclopamine and activation of Notch pathway with bexarotene decreased osteoblast differentiation and regulated receptor expression on both Ti surfaces, with more prominent effects on Ti-Nano.

Furthermore, the combination of purmorphamine and DAPT exhibited synergistic effects on osteoblast differentiation, especially on Ti-Nano. These findings suggest that the Hedgehog and Notch signalling pathways play important roles in osteoblast/Ti interactions and their effects are more intense on nanotopography.

Overall, this study provides insights into the cellular mechanisms that control the process of osseointegration and highlights the potential of developing strategies based on nanostructured surfaces to improve implant integration.