[Effect of different orthodontic forces on the expression of T helper cell 17 cell-related cytokines in the pressure side of periodontal tissue in rats].

OBJECTIVES: This study aimed to explore the changes in the expression of the characteristic transcription factor retinoid related orphan receptor γt (RORγt) and the cytokine interleukin-17 (IL-17) of T helper cell 17 (Th17) in the pressure side of the periodontal tissue of rats under different orthodontic forces. Their effects on the expression of osteoprotegerin (OPG) and the quantity of osteoclast (OC) were also explored. The role of Th17 cell in alveolar bone remodeling under different forces was preliminarily investigated. METHODS: A total of 108 rats were chosen and randomly divided into three groups. Mesial forces of 0, 50, and 100 g were loaded on the maxillary first molar in the three groups. The rats were executed at 0, 1, 3, 5, 7, and 14 days. The expression of RORγt mRNA was quantified by real-time quantitative polymerase chain reaction. The expression of IL-17 protein was quantified by enzyme linked immunosorbent assay. The expression levels of RORγt and OPG proteins were quantified, and the quantity of OC was counted via immunohistochemistry. RESULTS: The expression levels of RORγt and IL-17 and the quantity of OC increased first and then decreased in the 50 and 100 g groups, and the peak values of the two groups were on days 5 and 7, respectively. The expression levels in the 50 g group basically recovered to normal level on day 14, while that in the 100 g group remained at a high level. The expression levels in the 50 g group were higher than those in the 0 g group and lower than those in the 100 g group. The expression of OPG in the 50 g group decreased first, then increased, and finally decreased. It basically recovered to normal level on day 14. The expression of OPG in the 100 g group decreased first and then increased. It remained at a high level on day 14. The expression in the 50 g group was significantly higher than that in the 0 g group on day 7, while the expression in the 100 g group was significantly higher than that in the 0 g group on day 14. CONCLUSIONS: RORγt, IL-17, and OPG were expressed regularly over time under different orthodontic forces, indicating that Th17 participated in the process of bone resorption on the pressure side of periodontal tissue by secreting IL-17.

Overexpression of Csk-binding protein/phosphoprotein associated with glycosphingolipid-enriched microdomains induces cluster of differentiation 59-mediated apoptosis in Jurkat cells.

Csk-binding protein/phosphoprotein associated with glycosphingolipid-enriched microdomains (CBP/PAG) is a membrane-bound adaptor protein that downregulates the activation of Src family kinases present in lipid rafts. To elucidate the role of CBP/PAG in human T cell activation, a cell line overexpressing CBP/PAG was constructed and the function of CBP/PAG in Jurkat cells was examined. The present study revealed that increased CBP/PAG expression in T cells significantly enhanced their apoptosis and reduced cellular activation and proliferation. Overexpression of CBP/PAG suppressed the growth of Jurkat cells by recruiting c-Src and its negative regulator, C-terminal Src kinase (CSK), to lipid rafts. The negative regulation of CBP/PAG was enhanced in the presence of anti-cluster of differentiation (CD)59 monoclonal antibodies. In addition, a significant association was revealed between the location of CBP/PAG and CD59, which were co-expressed in the same region of the cell membrane, implicating a potential overlap of the elicited signaling pathways. These results indicate that CBP/PAG functions as a negative regulator of cell signal transduction and suggest that CD59 may strengthen the role of negative feedback regulation.

A role for GPI-CD59 in promoting T-cell signal transduction via LAT.

Cluster of differentiation 59 (CD59) is a glycosylphosphatidylinositol-anchored protein. Cross-linking of CD59 with specific monoclonal antibodies can cause a series of intracellular signal transduction events. However, the underlying molecular mechanisms are poorly understood. Linker for activation of T-cells (LAT) is a crucial adaptor protein in T-cell signaling, and its phosphorylation and palmitoylation are essential for its localization and function. In a previous study by the present authors, it was demonstrated that CD59 may be responsible for LAT palmitoylation, thereby regulating T-cell signal transduction. The present study detected the co-localization of LAT and CD59 in lipid rafts by transfecting Jurkat cells with lentivirus vectors carrying the LAT-enhanced green fluorescent protein fusion protein. In addition, LAT and CD59 were shown to have a synergistic effect on the proliferation of Jurkat cells. The results also indicated that CD59 may transfer the palmitate group from phosphatidylinositol to LAT to form LAT palmitate, which then localizes to lipid rafts to regulate T-cell activation. The results of the present study provided novel insights into the role of CD59 in T-cell signal transduction.

Notch signaling mediated by TGF-ß/Smad pathway in concanavalin A-induced liver fibrosis in rats.

AIM: To explore the exact interaction between Notch and transforming growth factor (TGF)-ß signaling in liver fibrosis. METHODS: We established a rat model of liver fibrosis induced by concanavalin A. Peripheral blood mononuclear cells (PBMCs) were isolated from the modeled rats, and cultured with γ-secretase inhibitor DAPT and TGF-ß inhibitor for 24 h. The mRNA levels of Notch and TGF-ß signaling were detected by quantitative real-time polymerase chain reaction. Expression of Notch and TGF-ß proteins was analyzed by western blotting. RESULTS: Compared to control rats, Notch and TGF-ß signaling was activated in PBMCs of model rats. Administration of DAPT and TGF-ß inhibitor suppressed Notch and TGF-ß signal transducer in PBMCs of model rats. DAPT reduced mRNA and protein expression of TGF-ß signaling, such as TGF-ß1 and Smad3. TGF-ß inhibitor also downregulated Notch1, Hes1 and Hes5, and mRNA and protein expression of the Notch signaling pathway. CONCLUSION: Notch and TGF-ß signaling play a role in liver fibrosis. TGF-ß signaling upregulates Notch signaling, which promotes TGF-ß signaling.