Lipopolysaccharides affect compressed periodontal ligament cells via Eph-ephrin signaling.

OBJECTIVES: The aim of this study is to investigate the underlying mechanism of the recovery of periodontal ligament cells (PDLCs) sequentially exposed to inflammation and mechanical loading. MATERIALS AND METHODS: We divided PDLCs into four groups: control; compressive force (CF) alone (2.0 g/cm2 ); lipopolysaccharides (LPS) pretreatment (0.1 µg/ml) followed by simultaneous LPS and CF stimulation, simulating uncontrolled periodontitis; and LPS pretreatment followed by CF exposure, simulating controlled periodontitis. The expression of EphB4-ephrinB2 and EphA2-ephrinA2, and the level of osteoclastogenesis and osteogenesis were evaluated. RESULTS: Simultaneous stimulation by LPS and CF, compared with CF alone and sequential LPS and CF exposure, significantly suppressed EphB4 and enhanced ephrinA2 expression. Similarly, the most intense osteoclastic differentiation was observed under simultaneous LPS and CF stimulation, while sequential exposure to LPS and CF only slightly increased osteoclastic cell numbers. Both the activation of EphB4 signaling and ephrinA2 silencing lowered osteoclastic differentiation, which had previously been upregulated by simultaneous LPS and CF stimulation. These treatments also increased osteogenic differentiation. CONCLUSIONS: Simultaneous LPS and CF stimulation critically enhances osteoclastogenesis in PDLCs through the suppression of EphB4 and the induction of ephrinA2 signaling. Sequential LPS and CF exposure partially abolishes the osteolytic effects of simultaneous stimulation.

Ageing and Inflammation: What Happens in Periodontium?

Periodontitis is a chronic inflammatory disease with a high incidence and severity in the elderly population, making it a significant public health concern. Ageing is a primary risk factor for the development of periodontitis, exacerbating alveolar bone loss and leading to tooth loss in the geriatric population. Despite extensive research, the precise molecular mechanisms underlying the relationship between ageing and periodontitis remain elusive. Understanding the intricate mechanisms that connect ageing and inflammation may help reveal new therapeutic targets and provide valuable options to tackle the challenges encountered by the rapidly expanding global ageing population. In this review, we highlight the latest scientific breakthroughs in the pathways by which inflammaging mediates the decline in periodontal function and triggers the onset of periodontitis. We also provide a comprehensive overview of the latest findings and discuss potential avenues for future research in this critical area of investigation.

Porphyromonas gingivalis lipopolysaccharide enhances the proliferation of human periodontal ligament cells via upregulation of cyclin D1, cyclin A and cyclin B1.

Human periodontal ligament cells (hPDLCs) play a notable role in periodontal tissue homeostasis and regeneration. However, the effect of Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) on the proliferation of hPDLCs remains unclear. The present study investigated the effects of Pg-LPS on the proliferation profile of hPDLCs, and the involvement of cyclins and cyclin-dependent kinases in the process. hPDLCs were treated with Pg-LPS, and cell proliferation and cycle were detected using Cell Counting Kit-8 assays and flow cytometry. The mRNA expression levels of the cyclins and cyclin-dependent kinases (CDKs), including cyclins A, B1, D1 and D2 and CDK1, 2 and 4, were detected using reverse transcription-quantitative PCR. The protein expression levels of cyclins A, B1 and D1 were analysed using western blotting. The proliferation of hPDLCs was significantly increased after treatment with Pg-LPS at the concentrations of 0.001, 0.01, 0.1, 1 and 10 µg/ml for 24, 36 and 48 h compared with the cells cultured without LPS (P<0.01). The proliferation index of hPDLCs was significantly enhanced after treatment with Pg-LPS (0.0001, 0.001, 0.01, 0.1, 1 and 10 µg/ml) for 24 h (P<0.01). However, the S-phase fraction (SPF) only significantly increased after treatment with Pg-LPS at 0.01 µg/ml for 24 h (P<0.05), while the G2/M-phase fraction increased (P<0.01) and the G0/G1-phase fraction decreased (P<0.01) compared with the controls. The proliferation index and SPF increased, peaked at 24 h and then decreased at 48 h in both Pg-LPS-stimulated and control groups. Notably, Pg-LPS significantly upregulated the expression levels of cyclins D1, A and B1 after 24 h compared with those in the controls. Overall, the present study indicated that Pg-LPS may enhance the proliferation of hPDLCs, potentially through upregulation of cyclins D1, A and B1.

Gemcitabine-loaded RGD modified liposome for ovarian cancer: preparation, characterization and pharmacodynamic studies.

BACKGROUND: Ovarian cancer is the third leading cause of death among gynecological cancers in women in China. Chemotherapy is an important method for comprehensive treatment of ovarian cancer, but the curative effect is poor. PURPOSE: In this study, gemcitabine (GEM) -loaded RGD modified liposomes (LPs) were developed by the emulsification-solvent evaporation method and evaluated for their antitumor activity in vitro and in vivo. METHODS: The physicochemical properties of LPs such as particle size, zeta potential and in vitro drug release were investigated. We also demonstrated the effect of RGD-GEM-PEG LPs in ovarian cancer. RESULTS: RGD-PEG3500-DSPE GEM LPs had a uniform spherical morphology. The mean particle size and polydispersity index were determined to be 106.7 nm and 0.13 respectively. The ER% and DL% of the formulation were 79.6±3.1% and 6.1±1.4% respectively. Compared with the free drug, RGD modified GEM LPs had sustained-release properties in vitro. In vivo, compared with the DiD-RGD-PEG3500-DSPE GEM LPs group, free DiD-GEM and DiD-GEM LPs had no obvious fluorescence intensity in tumor of mice at all times, indicating that ordinary liposomes and drugs had no tumor targeting function. RGD-PEG3500-DSPE GEM LPs showed a superior antiproliferative effect on SKOV3 cells and had a better antitumor effect in vivo than non-modified LPs. CONCLUSION: These results indicated that RGD-PEG3500-DSPE GEM LPs were a promising candidate for antitumor drug delivery.