OR23 - Comprehending Cellular Functions and Nanoparticle Therapeutics for Root Resorption Using a Periodontal Organoid Model

Abstract:
The study aims to characterize a heterogeneous collagen-based periodontal model to study cellular functions and the therapeutic effects of immunomodulatory nanoparticles in root resorption. The periodontal model was constructed using a two-stage technique consisting of periodontal fibroblasts (PDLF) and macrophages (Mφ). The developed model was exposed to inflammatory and resorptive stimuli with and without engineered chitosan nanoparticles (CSnp)/(CSDEX) for 7 days. On days 2 and 7, immunofluorescence analysis (IFA-CD80, CD206, NFATc1, STAT6, and periostin) and cytokine analysis (TNF-α, IL6, IL10, TGFβ1, MMP2, MMP9, OPG) were conducted. Statistical analyses using the t-test and one-way ANOVA with Tukey's multiple comparisons were used (p <.05). The developed 3D PDLF-Mφ model comprised a core of PDLF surrounded by Mφ (total diameter: 3.8×3.8 mm, thickness: 300-500µm) with a spatial arrangement of cells to simulate the PDL. IFA and cytokine analysis of the 3D model without nanoparticles showed higher expression of TNF-α, IL6, and STAT6. Treatment with nanoparticles resulted in Mφ polarization and clastic differentiation being downregulated with a reduction of CD80, NFATc1, STAT6 and upregulation of periostin in a temporal fashion. Cytokine analysis showed a differential response with CSnp and CSDEX. Both nanoparticles showed downregulation of TNF-α, MMP9, and upregulation of IL-10, MMP2, and IL6. TGF-β1 and OPG upregulation was observed with CSnp. The study highlights the role of TNFα, IL6, and STAT6 signaling in the PDLF-Mφ crosstalk when exposed to inflammatory and/or resorptive microenvironments. The engineered nanoparticles inhibited osteoclastic differentiation of Mφ by downregulating TNF-α, MMP9, NFATc1, STAT6, and upregulating IL-10 and TGF-β1.