Periodontal Regeneration Using a Mineralizing Hydrogel Loaded with a Synthetic CEMP1-Derived Peptide

Background: Periodontal regeneration requires the coordinated reconstruction of mineralized and non-mineralized tissues. P35 polypeptide derived from Cementum protein-1(CEMP1) has been demonstrated to induce bio-mineralization in vitro, although in vivo applications still need to be further validated. In this study, we developed a novel mineralizing hydrogel system (P35/ACP@PEG Hy) to facilitate periodontal regeneration by encapsulating P35-loaded amorphous calcium phosphate nanoparticles (P35/ACP-NPs) within a four-arm polyethylene glycol (PEG) hydrogel. Methods: In vitro assays were performed to characterize the physicochemical properties, sustained-release behavior, osteogenic/cementogenic effects of P35/ACP-NPs on hPDLCs, together with the mechanical performance and biocompatibility of the PEG hydrogel. The regenerative capacity of the hydrogel was further assessed in a rat periodontal defect model using micro-CT and histological staining. The regenerative efficacy was evaluated in a rat periodontal defect model via micro-CT and histological staining, while transcriptome sequencing (RNA-seq) and immune-blotting were further performed to confirm the molecular mechanisms. Results: P35/ACP@PEG exhibited favorable physicochemical properties, featuring an initial burst release followed by a sustained gradual release profile, along with the excellent biocompatibility. In vitro, P35/ACP-NPs markedly promoted osteogenic and cementogenic differentiation of hPDLCs. Correspondingly, the P35/ACP@PEG hydrogel significantly accelerated periodontal tissue regeneration in the rat model with periodontal defect. And RNA-seq analysis and immune-blotting further revealed that these effects are highly linked to activation of the TGF-β/Smad2/3/LOX signaling pathway. Conclusions: P35/ACP@PEG Hy platform can promote periodontal regeneration via activation of TGF-β/Smad2/3/LOX signaling pathway in vivo. Its sustained bioactivity, favorable biocompatibility and robust regenerative efficacy highlight a potential of P35 polypeptide for periodontal tissue repair.