The homeostasis and therapeutic applications of innate and adaptive immune cells in periodontitis

Impact of Hyaluronic Acid and Other Re-Epithelializing Agents in Periodontal Regeneration: A Molecular Perspective

This narrative review delves into the molecular mechanisms of hyaluronic acid (HA) and re-epithelializing agents in the context of periodontal regeneration. Periodontitis, characterized by chronic inflammation and the destruction of tooth-supporting tissues, presents a significant challenge in restorative dentistry. Traditional non-surgical therapies (NSPTs) sometimes fail to fully manage subgingival biofilms and could benefit from adjunctive treatments. HA, with its antibacterial, antifungal, anti-inflammatory, angiogenic, and osteoinductive properties, offers promising therapeutic potential. This review synthesizes the current literature on the bioactive effects of HA and re-epithelializing agents, such as growth factors and biomaterials, in promoting cell migration, proliferation, and extracellular matrix (ECM) synthesis. By modulating signaling pathways like the Wnt/β-catenin, TGF-β, and CD44 interaction pathways, HA enhances wound healing processes and tissue regeneration. Additionally, the role of HA in facilitating cellular crosstalk between epithelial and connective tissues is highlighted, as it impacts the inflammatory response and ECM remodeling. This review also explores the combined use of HA with growth factors and cytokines in wound healing, revealing how these agents interact synergistically to optimize periodontal regeneration. Future perspectives emphasize the need for further clinical trials to evaluate the long-term outcomes of these therapies and their potential integration into periodontal treatment paradigms.

The spatial transcriptomic landscape of human gingiva in health and periodontitis

The gingiva is a key oral barrier that protects oral tissues from various stimuli. A loss of gingival tissue homeostasis causes periodontitis, one of the most prevalent inflammatory diseases in humans. The human gingiva exists as a complex cell network comprising specialized structures. To understand the tissue-specific pathophysiology of the gingiva, we applied a recently developed spatial enhanced resolution omics-sequencing (Stereo-seq) technique to obtain a spatial transcriptome (ST) atlas of the gingiva in healthy individuals and periodontitis patients. By utilizing Stereo-seq, we identified the major cell types present in the gingiva, which included epithelial cells, fibroblasts, endothelial cells, and immune cells, as well as subgroups of epithelial cells and immune cells. We further observed that inflammation-related signalling pathways, such as the JAK-STAT and NF-κB signalling pathways, were significantly upregulated in the endothelial cells of the gingiva of periodontitis patients compared with those of healthy individuals. Additionally, we characterized the spatial distribution of periodontitis risk genes in the gingiva and found that the expression of IFI16 was significantly increased in endothelial cells of inflamed gingiva. In conclusion, our Stereo-seq findings may facilitate the development of innovative therapeutic strategies for periodontitis by mapping periodontitis-relevant genes and pathways and effector cells.

TIPE2 regulates periodontal inflammation by inhibiting NF-κB p65 phosphorylation

BACKGROUND

The roles and molecular mechanisms of tumor necrosis factor-α-induced protein 8-like 2 (TIPE2) in periodontitis remain largely unknown.

OBJECTIVE

This study aimed to determine the expression of TIPE2 and NF-κB p65 in rat Porphyromonas gingivalis-induced periodontics in vivo.

METHODOLOGY

Periodontal inflammation and alveolar bone resorption were analyzed using western blotting, micro-computed tomography, TRAP staining, immunohistochemistry, and immunofluorescence. THP-1 monocytes were stimulated using 1 μg/ml Pg. lipopolysaccharide (Pg.LPS) to determine the expression of TIPE2 in vitro. TIPE2 mRNA was suppressed by siRNA transfection, and the transfection efficiency was proven using western blotting and real-time PCR. The NF-κB pathway was activated by treating the cells with 1 μg/ml Pg.LPS to explore related mechanisms.

RESULTS

The expression of both TIPE2 and NF-κB p65 was increased in the gingival tissues of rat periodontitis compared with normal tissues. Positive expression of TIPE2 was distributed in inflammatory infiltrating cells and osteoclasts in the marginal lacunae of the alveolar bone. However, strong positive expression of TIPE2 in THP-1 was downregulated after Pg.LPS stimulation. TIPE2 levels negatively correlated with TNF-α and IL-1β. Decreased TIPE2 in THP-1 further promoted NF-κB p65 phosphorylation. Mechanistically, TIPE2 knockdown upregulated NF-κB signaling pathway activity.

CONCLUSIONS

Taken together, these findings demonstrate that TIPE2 knockdown aggravates periodontal inflammatory infiltration via NF-κB pathway. Interventions aimed at increasing TIPE2 may help in the therapeutic applications for periodontitis.