Lysosomal membrane protein Sidt2 knockout induces apoptosis of human hepatocytes in vitro independent of the autophagy-lysosomal pathway / 南方医科大学学报

OBJECTIVE@#To explore the regulatory mechanism of human hepatocyte apoptosis induced by lysosomal membrane protein Sidt2 knockout.@*METHODS@#The Sidt2 knockout (Sidt2-/-) cell model was constructed in human hepatocyte HL7702 cells using Crispr-Cas9 technology.The protein levels of Sidt2 and key autophagy proteins LC3-II/I and P62 in the cell model were detected using Western blotting, and the formation of autophagosomes was observed with MDC staining.EdU incorporation assay and flow cytometry were performed to observe the effect of Sidt2 knockout on cell proliferation and apoptosis.The effect of chloroquine at the saturating concentration on autophagic flux, proliferation and apoptosis of Sidt2 knockout cells were observed.@*RESULTS@#Sidt2-/- HL7702 cells were successfully constructed.Sidt2 knockout significantly inhibited the proliferation and increased apoptosis of the cells, causing also increased protein expressions of LC3-II/I and P62(P < 0.05) and increased number of autophagosomes.Autophagy of the cells reached a saturated state following treatment with 50 μmol/L chloroquine, and at this concentration, chloroquine significantly increased the expressions of LC3B and P62 in Sidt2-/- HL7702 cells.@*CONCLUSION@#Sidt2 gene knockout causes dysregulation of the autophagy pathway and induces apoptosis of HL7702 cells, and the latter effect is not mediated by inhibiting the autophagy-lysosomal pathway.

Toxicity of N-Succinyl-Chitosan to Bovine Hemoglobin and Human Liver Cells / 中国药学杂志

OBJECTIVE: To investigate the toxicity of N-succinyl-chitosan (NSCS) to bovine hemoglobin (BHb) and human liver cells (HL-7702). METHODS: BHb was used as a research object and the toxic effect of NSCS was investigated by UV-Vis absorption spectroscopy, fluorescence spectroscopy and synchrotron spectroscopy under the simulative human physiological condition. At the same time, human HL-7702 cells was used as a research object and methyl thiazolyl tetrazolium (MTT) assay was employed to examine the cytotoxicity of NSCS. RESULTS: The results of UV-Vis absorption spectroscopy and MTT showed that the toxicity of NSCS was weak, and substitution degree had little effect on it. The result of fluorescence spectroscopy demonstrated that the intrinsic fluorescence of BHb was quenched by NSCS and the quenching effect slightly increased with the increase of substitution degree. The quenching mechanism was mainly dynamic quenching, and the major driving forces were hydrophobic and electrostatic force. CONCLUSION: The result of synchronous fluorescence spectroscopy reveals that NSCS has almost no influence on the conformation of BHb. The toxicity of NSCS to BHb and HL-7702 is weak.

An investigation of trichloroethylene-induced effects on histone methylation in L-02 hepatic cells / 中华预防医学杂志

Objective@#To further explore TCE-induced hepatotoxicity and its mechanisms by identification of trichloroethylene (TCE) induced abnormal histone methylation in human liver cells.@*Methods@#L-02 cells were treated with 0 and 8 mmol/L TCE for 24 h. Histones were extracted by acid. Liquid chromatography electrospray ionization tandem mass spectrometry (ESI-LC-MS/MS) were used to identify and quantify TCE related histone methylations. TCE induced abnormal methylation of H3K79 me2 and H3K79 me3 were validated by Western blot analysis. The further analysis of the function of histone abnormal methylation modifications were done by single cell gel electrophoresis (SCGE) and Western blot analysis of p53 and ɤH2AX.@*Results@#After treatment with TCE for 24 h in L-02 cells, the 36 TCE related histone methylation sites in 28 peptide segments were identified by MS. After treatment with TCE in concentrations of 0 and 8.0 mmol/L in L-02 cells for 24 h, the relative expression level of histone H3K79 me3 were 1.00±0.06, 0.70±0.09 (t=15.01, P=0.015); the relative expression level of histone H3K79 me2 were 1.00±0.05, 0.74±0.07 (t=16.69, P=0.018); the Olive Tail Moment about DNA damage were 1.46±0.28, 3.12± 0.68 (t=15.22, P=0.018); the relative expression levels of p53 were 1.00±0.04, 1.24±0.04 (t=18.71, P= 0.012); and the relative expression levels of ɤH2AX were 1.00 ± 0.03, 1.56 ± 0.11 (t=8.32, P=0 045).@*Conclusion@#TCE can induce changes in the relative expression level of H3K79 me2 and H3K79 me3 in L-02 cell, and induce DNA damage, suggesting that TCE may induce changes in the relative expression level of H3K79 me2 and H3K79 me3 by DNA damage.

Radioprotective effects of nitroxides R-1 on human liver cells L-02 / 中华放射医学与防护杂志

Objcetive To investigate the protective effects of the nitroxides R-1 on human liver cells exposed to ionizing radiation.Methods Human liver cells L-02 were cultured and irradiated with 60Co γ-rays at the doses of 0,1,2,4,and 8 Gy,in order to screen the proper irradiation dose.WR2721 at the terminal concentration of 4 mmol/L was used as positive control.L-02 cells irradiated with 4 Gy were added with R-1 at the terminal concentration of 0.25 μmol/L at 30 min before irradiation or immediately after irradiation.MIT method was used to screen the proper conditions for follow-up experiment 72 h later.L-02 cell culture fluid was added with R-1 at the concentrations of 0,0.125,0.25,0.5,and 1 μmol/L,respectively for 30 min before irradiation at the doses of 0,1,2,4,and 8 Gy to ealculate clone formation rate at 10 d post-irradiation.L-02 cells were cultured and divided into 4 groups:control group without any treatment.drug group pretreated by 0.25 μmol/L R-1 only,irradiation group,irradiated at 4 Gy only,and drug + irradiation group with combination of 0.25 μmol/L R-01 and 4 Gy irradiation.The inverted microscopy and Hoechst 33258 staining and flow eytometry were used to observe the apoptosis of the cells at 24,48,and 72 h later.Results Nitroxides R-1 did not inhibit the viability of L-02 cell when its concentration was less than 1 μmol/L and it inhibited the L-02 cell growth when the concentration wu higher than 2 μmoL/L.The A value and colony formation rate of different concentration of R-1 groups were all higher than those of the irradiation group,and the effect of the 0.25 μmol/L drug concentration group was the most significant.Consequently,the concentration 0.25 μmoL/L was selected for follow-up experiment.Compared with the irradiation group,the L-02 cells of the pretreatment group showed solid adherence, increased refraction,clear outline,less apoptotic and dead cells at 4 Gy post-irradiation.Conclusions Nitroxides R-1 can protect the human liver cells from 60Coγ-ray induced injury effectively.The mechanism of its protective effect may be the reduction of apoptosis.

Antagonistic effect of scutellarin on toxicity of selenium in human liver cells L-02 / 中草药

Object To investigate the antagonistic effect of scutellarin on the toxicity of selenium in human liver cells L-02. Methods MTT method was used to observe the effects of scutellarin and selenium on cell growth. The morphological changes of cells were observed by fluorescent microscope. The MDA level, thiol content, and total antioxidative capacity of cells were also measured. Results The optimum condition for scutellarin to promote cell growth was 0.5 mmol/L in 48 h culture period. Comparing with the only selenium treated group, 0.5 mmol/L scutellarin significantly antagonized the inhibition of cell growth caused by 1 and 5 ?mol/L selenium, suppressed the selenium-induced cell damage and the increase of MDA content, as well as increased the thiol content and cell antioxidation capacity. Conclusion Scutellarin markedly antagonizes the toxicity of selenium in human liver cells L-02 by inhibiting lipid peroxidation and promoting cellular antioxidation capacity.