PRMT5 inhibition ameliorates inflammation and promotes the osteogenic differentiation of LPS‑induced periodontal stem cells via STAT3/NF‑κB signaling

Ginsenoside Rb3 alleviates the formation of osteoclasts induced by periodontal ligament fibroblasts in the periodontitis microenvironment through the STAT3 pathway

This study explores the potential role and mechanism of Ginsenoside Rb3 (Rb3) in modulating osteoclastogenesis induced by human periodontal ligament fibroblasts (hPLFs) within the periodontitis microenvironment. We investigated the anti-inflammatory effects of Rb3 on hPLFs stimulated with Porphyromonas gingivalis lipopolysaccharide (P.g-LPS) utilizing quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay techniques. Moreover, the functional role of Rb3 in hPLFs-induced osteoclast formation was assessed by treating human bone marrow-derived macrophages (hBMMs) with conditioned medium from hPLFs, followed by analyses through qPCR, western blot analysis, and staining for tartrate-resistant acid phosphatase (TRAP) and phalloidin. The impact of Rb3 on the activation of the STAT3 signaling pathway was determined via western blot analysis. Results indicated that Rb3 treatment significantly suppressed the upregulation of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, MCP-1, and IL-18) at both gene and protein levels in hPLFs induced by P.g-LPS. Furthermore, conditioned medium from Rb3 plus P.g-LPS treated hPLFs notably decreased the number of TRAP-positive cells, actin ring formations, and the expression of osteoclast marker genes (including CTSK, NFATC1, and ACP5). Rb3 also inhibited the P.g-LPS-induced activation of the STAT3 pathway, with the activation of STAT3 partially reversing the effects of Rb3 on inflammation and osteoclast differentiation. Collectively, Rb3 ameliorates inflammation in P.g-LPS-stimulated hPLFs and reduces hPLFs-induced osteoclastogenesis by inhibiting the STAT3 signaling pathway, suggesting its potential as a therapeutic agent for periodontitis.

Protein arginine methyltransferase 5 in osteoblasts promotes the healing of extraction sockets

OBJECTIVES

To explore the effect of protein arginine methyltransferase 5 (PRMT5) on tooth extraction sockets healing, we established an extraction sockets model in osteoblast-conditional Prmt5 knockout mice. The results provided clues for promoting extraction sockets healing in clinical settings.

MATERIALS AND METHODS

Maxillary first molars were extracted from 6 to 8-week-old mice to establish an extraction fossa model. Microcomputed tomography (Micro-CT), histology, and immunostaining assays were performed on samples harvested at 3-, 7-, and 14-day post-extraction. Prmt5-silenced cell lines  were employed to explore the regulatory mechanisms underlying the osteigenic differentiation.

RESULTS

PRMT5 expression was higher in the early stage of socket healing. Micro-CT analysis showed that the percentage of new bone in the extraction sockets was lower in OC-Cre; Prmt5fl/fl mice than in the control group, consistent with Masson staining. We found that, Prmt5 deficiency delayed the osteogenesis during extraction socket healing, which might be achieved through the decrease of H4R3me2s in the Sp7 promoter region.

CONCLUSION

PRMT5 in osteoblasts may promote the differentiation of osteoblasts by regulating the Sp7 promoter H4R3me2s and participate in the healing of tooth extraction sockets.