RGD Peptide-Based Hydrogel Enhances the Osteogenic Differentiation of Periodontal Ligament Stem Cells via Wnt Signaling.

Abstract

Introduction: Periodontitis results in progressive loss of gingival tissue and periodontal ligament, eventually resulting in tooth instability. As regenerating degraded periodontal tissue is not possible without intervention, therefore, a tissue-engineered substitute is a good option. Bone regeneration strategies often rely on either biochemical stimulation or engineered scaffolds, but rarely in a coordinated manner. Arginine-Glycine-Aspartic acid (RGD) hydrogel provides a unique combination of biocompatibility and biodegradability, making it an attractive scaffold for tissue engineering. The study aims to investigate the effect of combining Wnt pathway activation with Arginine-Glycine-Aspartic acid (RGD) hydrogel (a three-dimensional environment, 3D) to enhance the osteogenic differentiation of mesenchymal stem cells (MSCs) derived from periodontal ligament tissue.

Methods: The cells were isolated from the root of the extracted tooth. They were grown in an osteogenic medium with and without a Wnt activator in two-dimensional (2D) and RGD hydrogel- based 3D environments to expand in vitro. Osteogenic gene expression was evaluated by qPCR in 2D and 3D cultures. Mesenchymal stem cells isolated from periodontal ligament tissue showed osteogenic differentiation when cultured in a differential medium with or without the Wnt signaling activator, CHIR99021 (a GSK3β inhibitor).

Results: The data of our study revealed that osteogenic genes were expressed in both 2D- and 3D-- cultured cells. However, higher expression of osteogenic genes was found in Wnt signaling-activated cells. Furthermore, the RGD hydrogel provided better differentiation efficacy and a significant increase (p < 0.001) in terms of Wnt-activated differentiation.

Discussion: The RGD hydrogel-Wnt activation model described in this study holds strong potential for translation into preclinical bone regeneration strategies. By enhancing osteogenic differentiation through a synergistic interaction between the Wnt signaling pathway and the 3D peptide hydrogel matrix, this platform offers a promising approach to early-stage testing of bone regeneration therapies.

Conclusion: Hence, the Arg-Gly-Asp (RGD) hydrogel-based 3D microenvironment along with a Wnt signaling activator provides superior efficacy in differentiation since it allows cell encapsulation and an environment that closely simulates native tissues. Therefore, these findings highlight the synergistic effect of biochemical and biophysical cues in directing stem cell fate and offer a promising strategy for advancing stem cell-based bone tissue engineering.