Helicobacter pylori inhibited cell proliferation in human periodontal ligament fibroblasts through the Cdc25C/CDK1/cyclinB1 signaling cascade

PURPOSE: Several studies have shown that the oral cavity is a secondary location for Helicobacter pylori colonization and that H. pylori is associated with the severity of periodontitis. This study investigated whether H. pylori had an effect on the periodontium. We established an invasion model of a standard strain of H. pylori in human periodontal ligament fibroblasts (hPDLFs), and evaluated the effects of H. pylori on cell proliferation and cell cycle progression. METHODS: Different concentrations of H. pylori were used to infect hPDLFs, with 6 hours of co-culture. The multiplicity of infection in the low- and high-concentration groups was 10:1 and 100:1, respectively. The Cell Counting Kit-8 method and Ki-67 immunofluorescence were used to detect cell proliferation. Flow cytometry, quantitative real-time polymerase chain reaction, and western blots were used to detect cell cycle progression. In the high-concentration group, the invasion of H. pylori was observed by transmission electron microscopy. RESULTS: It was found that H. pylori invaded the fibroblasts, with cytoplasmic localization. Analyses of cell proliferation and flow cytometry showed that H. pylori inhibited the proliferation of periodontal fibroblasts by causing G2 phase arrest. The inhibition of proliferation and G2 phase arrest were more obvious in the high-concentration group. In the low-concentration group, the G2 phase regulatory factors cyclin dependent kinase 1 (CDK1) and cell division cycle 25C (Cdc25C) were upregulated, while cyclin B1 was inhibited. However, in the high-concentration group, cyclin B1 was upregulated and CDK1 was inhibited. Furthermore, the deactivated states of tyrosine phosphorylation of CDK1 (CDK1-Y15) and serine phosphorylation of Cdc25C (Cdc25C-S216) were upregulated after H. pylori infection. CONCLUSIONS: In our model, H. pylori inhibited the proliferation of hPDLFs and exerted an invasive effect, causing G2 phase arrest via the Cdc25C/CDK1/cyclin B1 signaling cascade. Its inhibitory effect on proliferation was stronger in the high-concentration group.

Design, screening and antimicrobial activity of novel peptides against / 南方医科大学学报

OBJECTIVE@#To construct antimicrobial peptides with potent antimicrobial activity, low cytotoxicity and efficient killing rate of for prevention and treatment of dental caries.@*METHODS@#We exploited the existing design strategies to modify reutericin 6 or gassericin A produced by species in the oral cavity based on their cationicity, amphipathicity and -helical structure. We examined their antimicrobial activities using bacterial susceptibility assay, their cytotoxicity through cytotoxicity assay and their killing rate of with time-kill assay. We further evaluated the candidate derivatives for their killing rate against , their antimicrobial activity against different oral pathogens and the development of drug resistance.@*RESULTS@#We constructed 6 AT-1 derivatives, among which AT-7 showed an MIC of 3.3 μmol/L against , and with a killing rate of 88.7% against within 5 min. We did not obtain strains of resistant to AT- 7 after induction for 10 passages.@*CONCLUSIONS@#Hydrophobicity and imperfect amphipathic structure are two key parameters that define the antimicrobial potency of the antimicrobial peptides. The imperfectly amphipathic peptide AT-7 shows the potential for clinical application in dental caries treatment.

Effect of low-frequency pulsed electromagnetic field combined with whole-body vibration on bone density and mechanics performance of disuse osteoporosis rats / 中华骨科杂志

Objective To discuss the effect of low-frequency pulsed electromagnetic field (ELF-PEMFs) combined with-whole-body vibration(WBV) on the bone mineral density,bone microstructure and the biological mechanics performance inhindlimb unloading osteoporosis rats.Methods Forty female 4 months aged SD rats were randomly divided into five groups:blank group,control group,ELF-PEMFs group,WBV group,low-frequency pulsed electromagnetic field combined with wholebody-vibration(ELF-PEMFs + WBV) group.The blank group was the normal control which comprise the healthy rats.The controlgroup was the disused osteoporosis model.Except for the blank group,thehind limb unloading rats were kept for six weeks.No intervention were provided to the blank group and the control group,other three groups were treated with physical therapy.The bodyweight of rats in each group was record.Bone mineral density was measured by Dual energy X-ray absorptiometry.The right femurs was analyzed by Micro-CT and the left femur was tested through a biomechanical machine.Results After 8 weeks of continuous treatment,the ELF-PEMFs group,WBV group,ELF-PEMFs+WBV group were significantly increased in weight and bonedensity (PELF-PEMFs=0.015,PWBV=0.016,PELF-PEMFs+WBV=0.007),(tELF-PEMFs=5.956,PELF-PEMFs=0.000;tWBV=6.127,PWBV=0.000;tELF-PEMFs+WBV=4.639,PELF-PVMFs+WBV=0.000).The difference was statistically significant (F=0.091,P=0.018).The ELF-PEMFs +WBV group was significantly higher in bone formation index.The items of BV/TV,Tb.N,Tb.Th and SMI in Micro-CT analysis increased,while Tb.Sp and Conn.D index decreased significantly.Trabecular bone structure of all the three groups was improved,however the ELF PEMFs +WBV group was better than the other two groups (vs.ELF-PEMF group,PBV/TV=0.041,PTb.N=0.026,PTb.Th=0.009,PConn.D=0.030,PTb.Sp=0.045,PSMI=0.032;VS.WBV group,PBv/Tv=0.018,PTb.N=0.004,PTb.Th=0.022,PConn.D=0.042,PTb.Sp=0.039,PSMI=0.049).The maximum load,energy absorption and bone stiffness index in biomechanicalperformance test were improved.The combination treatment group were significantly improved (F=0.167,P=0.038).Conclusion Low-frequencypulsed electromagnetic field combined with whole body vibration therapy can improve bone mineral density,bone microstructureand the biological mechanics performance.They have synergistic effect and the combination therapy is better than single treatment.

Study on the transfection of dextran derivative nanoparticles to the mda-mb-435 human breast cancer cells / 中国药理学通报

Aim To prepare the dextran derivative nanoparticles with higher transfecting efficiency to mda-mb-435 human breast cancer cells.Methods The dextran 40 and the sodium periodate were reacted with different mole ratio to form the intermediate:oxidized dextrans having different aldehyde content.With different reactants matching,the spermine were grafted onto the oxidized dextrans mentioned above to form the dextran-spermine imine conjugates which were reduced by the excess reducing agent NaBH4 to produce the end products 9 species of dextran derivative nanoparticles(extran-spermine amine conjugates).The dextran derivative nanipartical of the highest gene transfecting efficiency was selected from the 9 species of dextran derivative nanoparticles by the experiment of gene transfection,using the pEGFP-C1 plasmid as the reporter,the mda-mb-435 human breast cancer cells as the transfected cells.Results The dextran derivative nanoparticles with the highest transfecting efficiency was the one that had the highest content of spermine grafted onto the oxidized dextran40 obtained by the reaction between sodium periodate and dextran40 with the mole ratio of 0.8.Conclusion The dextran derivative nanoparticles of the highest transfecting efficiency to the mda-mb-435 human breast cancer had been prepared.

Effects of Ganoderma Polysacchrides on PKC and PKA Activities in Murine T Cells / 中国药房

AIM：To investigated the effects of Ganoderma polysaccthride(GLB7)on protein kinase A(PKA) and protein kinase C(PKC) activitives in murine T cells.METHODS：A new ion-pair reversed-phase high liquid chromatography method was used to determinate the activities of PKA and PKC in T cells.RESULTS：GLB7 could markedly increase the activities of PKA and PKC in murine T cells in a dose-dependent manner.The peak time was at 5 min and 20 min and the activities of PKA and PKC returned to basic level at 20 min and 1.5h respectively.GLB7 could induce translocation of PKC and antagonize the inhibition effect of staurosporine(10μ mol· L-1) on PKC in T cells.CONCLUSION：The immunopotentiating and antitumour effects of Ganoderma polysacchride may be associated with its activation on PKA and PKC in murine T cells.

Effect of Ganoderma polysacchride on intracellular free calcium and intracellular pH in murine T cells / 中国药理学通报

AIM　To extend the approach of the act ion of ganoderma polysacchride on intracellular signal events in T cells. METHODS　Laser scanning confocal microscope imaging of the calcium and p H fluorescent indicator dye Fluo-3/AM and SNARF-1/AM were used to determine th e kinetic changes of ［Ca2+］i and ［pH］i in murine T cells induced b y a ganoderma polysacchride,designated GLB7. RESULTS　It was fou nd that GLB7(20 mg*L-1) could increase ［Ca2+］i and ［pH］i at 1 min were 334.7%±16.4%(n=3)、171.6%±10.4%(n=3) respectively. T he increase in ［Ca2+］i induced by GLB7 was due to the influx of extr acellular Ca2+ and intracellular Ca2+ release through both IP3-se nsitive and IP3-insensitive Ca2+ stores, and increase in ［pH］i indu ced by GLB7 was relative to Na+/H+ exchange systems and ［Ca2+］i. GLB 7 did not influence ［Ca2+］i and ［pH］i in murine T cells induced by Con A(3 mg*L-1). CONCLUSION　Stimulation of the increase in ［Ca2+］i and ［pH］i may be an important channel for gano derma polysacchrides to achieve their pharmacological actions.

Effect of chitosan on PKC activity and DAG concentration in murine peritoneal macrophages / 中国药理学通报

ABSTRACT AIM To investigate the effect of ch-itosan on protein kinase C (PKC) activitives and diacyl glycerol(DAG)concentration in murine peritoneal macrophages. METHODS A new ion-pair reversed-phase high liquid chromatography and ra-dioimmunoassay were used to determinate the activity of PKC and the concentration of DAG respectively. RESULTS ( 1) Chitosan induced activation and translocation of PKC in murine peritoneal macrophages. The peak time was 25 min and the activity of PKC came back the basic level at 1. 5 h. (2)Chitosan increased the production of DAG in murine peritoneal macrophages. The peak time was 30 s and the concentration of DAG came back the basic level at 3 min. CONCLUSION The im-munopoteniating effect of chitosan may be associated with the channel of DAG /PKC.