Role of Toll-like receptor 2/4-nuclear factor-κB signaling pathway in invasion of Mycobacterium tuberculosis to mouse dendritic cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the mechanism of Mycobacterium tuberculosis invasion to mouse dendritic cells (DC).</p><p><b>METHODS</b>Mycobacterium tuberculosis strain H37Rv was co-cultured with mouse DC2.4 cells.The mRNA expression of Toll-like receptor 2/4(TLR2/4) in DC2.4 cells was detected by fluorescent quantitative real-time PCR and the protein expression of nuclear factor κB(NF-κB) was assessed by Western blotting.The extracellular concentration of tumor necrosis factor α(TNF-α) was measured by ELISA methods during Mycobacterium Tuberculosis invasion.Indirect immunofluorescent staining and flow cytometry assay were used to detect the expression of CD80 and CD86 on DC2.4 cells before and after invasion.</p><p><b>RESULTS</b>The invasion of Mycobacterium tuberculosis in DC2.4 cells was observed after 2 h of co-incubation.The rates of invasion were (37.9±5.6)%,(51.2±7.6)%,(57.2±8.9)% and(63.9±6.8)% at 6,8,10 and 12 h after co-incubation,respectively.The mRNA expression level of TLR2 /4 was significantly increased at 6 h but decreased at 10 h after co-incubation.The expressions of NF-κB p65 and TNF-α were higher in DC2.4 cells after being invaded by 6,8,and 10 h and then gradually decreased.CD80 and CD86 expression were increased on DC2.4 at 6 h after co-incubation.</p><p><b>CONCLUSION</b>Invasion of Mycobacterium tuberculosis strain H37Rv to DC might enhance its antigen-presenting function through activation of TLR2/4-NF-kB signaling pathway.</p>

Effects of snakegourd root polysaccharide on apoptosis of MCF-7 cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of snakegourd root polysaccharide on apoptosis of human breast cancer cells (MCF-7 cells).</p><p><b>METHODS</b>Colorimetric MTT assay was used to measure the inhibition of snakegourd root polysaccharide on MCF-7 cells. The morphological changes of MCF-7 cells were observed by fluorescence microscope after DAPI staining and transmission electron microscope. The apoptosis of MCF-7 cells was examined by DNA agarose gel electrophoresis analysis of DNA fragmentation amd flow cytometry. The activity of Caspase-3 and Caspase-8 was detected by colorimetric assay.</p><p><b>RESULTS</b>Polysaccharide of snakegourd root significantly inhibited MCF-7 cells in a dose-and time-dependent manner. The nuclear condensation and marginalization were observed by DAPI staining and transmission electron microscope. The characteristic ladder of apoptosis in DNA electrophoresis was detected in MCF-7 cells treated with 10.0 μmol/L polysaccharide of snakegourd root at d 2. The activities of Caspase-3 and Caspase-8 were increased in a time-dependent manner. The rates of apoptosis in MCF-7 cells were (5.2 ±1.3)%, (13.1 ±4.7)%, (27.6 ±6.8)% and (43.8 ±9.8)% treated with 1.0,5.0,10.0 and 20.0 μmol/L snakegourd root polysaccharide at d 2,respectively. The maximal activities of intracellular Caspase-3 and Caspase-8 were (2.32 ±0.12)U/μg and (1.92 ±0.11)U/μg at d 2 and d 1, respectively when MCF-7 cells were treated with 10.0 μmol/L.</p><p><b>CONCLUSION</b>The polysaccharide of snakegourd root can induce the apoptosis of MCF-7 cells,which is associated with the activation of intracellular Caspase-3 and Caspase-8.</p>