PER2-mediated ameloblast differentiation via PPARγ/AKT1/β-catenin axis / 国际口腔科学杂志·英文版

Circadian rhythm is involved in the development and diseases of many tissues. However, as an essential environmental regulating factor, its effect on amelogenesis has not been fully elucidated. The present study aims to investigate the correlation between circadian rhythm and ameloblast differentiation and to explore the mechanism by which circadian genes regulate ameloblast differentiation. Circadian disruption models were constructed in mice for in vivo experiments. An ameloblast-lineage cell (ALC) line was used for in vitro studies. As essential molecules of the circadian system, Bmal1 and Per2 exhibited circadian expression in ALCs. Circadian disruption mice showed reduced amelogenin (AMELX) expression and enamel matrix secretion and downregulated expression of BMAL1, PER2, PPARγ, phosphorylated AKT1 and β-catenin, cytokeratin-14 and F-actin in ameloblasts. According to previous findings and our study, BMAL1 positively regulated PER2. Therefore, the present study focused on PER2-mediated ameloblast differentiation and enamel formation. Per2 knockdown decreased the expression of AMELX, PPARγ, phosphorylated AKT1 and β-catenin, promoted nuclear β-catenin accumulation, inhibited mineralization and altered the subcellular localization of E-cadherin in ALCs. Overexpression of PPARγ partially reversed the above results in Per2-knockdown ALCs. Furthermore, in in vivo experiments, the length of incisor eruption was significantly decreased in the circadian disturbance group compared to that in the control group, which was rescued by using a PPARγ agonist in circadian disturbance mice. In conclusion, through regulation of the PPARγ/AKT1/β-catenin signalling axis, PER2 played roles in amelogenin expression, cell junctions and arrangement, enamel matrix secretion and mineralization during ameloblast differentiation, which exert effects on enamel formation.

Effects of sevoflurane pretreatment on lung metastasis of mouse Lewis lung cancer cells / 临床麻醉学杂志

Objective To observe the effects of sevoflurane pretreatment on lung metastasis of mouse Lewis lung cancer (LLC)cells.Methods Mouse LLC cells were inoculated in culture plate. After being cultured for 24 h the cells were randomly divided into four groups:group control (CC), group 1% sevoflurane (SC1),group 2% sevoflurane (SC2),and group 3% sevoflurane (SC3).Cells of group SC1-3 were exposed to 1%,2%,3% sevoflurane for 4 h respectively,cells of group CC were exposed to 95%O 2-5%CO 2 mixture air,and were then cultured for another 24 h.The invasive activity of cells was determined by Transwell assay.The migration of cells was evaluated by wound scratch assay.The expression of MMP-2 and MMP-9 in cells were detected by ELISA.Thirty-two C57BL/6 mice were divided into four groups (n = 8):group control (CM),group 1% sevoflurane (SM1),group 2% sevoflurane (SM2),and group 3% sevoflurane (SM3).LLC cells of group SC1-3 were injected into caudal vein of mouse in group SM1-3 respectively.Cells of group CC were injected into mouse of group CM.Lung metastasis inhibitory rates were evaluated after 3 weeks. Results Compared with group CC,the invasive activity and migration of cells in group SC1-3 were decreased significantly,group SC1 >group SC2 >group SC3 (P group SC2>group SC3 (P <0.05).Compared with group CM,lung metastasis inhibitory rates of group SM1-3 were increased significantly,group SM1 < group SM2 < group SM3 (P < 0.05 ). Conclusion Sevoflurane can inhibit the lung metastasis of mouse LLC cells,which maybe through down-regulating the expression of MMP-2 and MMP-9 in mouse LLC cells.

Effects of mitogen-activated protein kinase p38 on CD3/CD28-stimulated T-cell proliferation and IL-2 expression enhauced by shockwaves / 吉林大学学报(医学版)

Objective To investigate the effects of mitogen-activated protein kinase p38(p38 MAPK)on CD3/CD28-stimulated T-cell proliferation and IL-2 expression which were enhanced by shockwaves.Methods Jurkat T cells or peripheral blood mononuclear cells(PBMC)were pretreated with the p38 MAPK-inhibitor(SB203580)(The Jurkat T cells or PBMC of the control groups were not pretreated with SB203580),then treated with shockwaves,and stimulated respectively with a suboptimal dose of anti-CD3 and anti-CD28 antibodies or PHA.Finally the IL-2 productions of Jurkat T cells or the proliferation of PBMC were respectively measured.The protein tyrosine phosphorylation of p38 MAPKin Jurkat T cells treated either with shockwaves or not was measured by Western blotting with anti-phosphotyrine antibodies(Thr180/Tyr182).The expressoins of p38 MAPK in Jurkat T cells treated either with shockwaves or not were determined by Western blotting with anti-p38 MAPK antibodies.Results Compared with negative control group without shockwave treatment,the 3H-TdR incorporation of the phytohemagglutinin-stimulated PBMC,which were treated with low dose shockwaves(LDSWs)of 100,150,200,250,300,330 impulses at(0.180?0.015)mJ?mm2,increased significantly(P