OBJECTIVETo study the effect of silicon dioxide nanoparticles on the expression and promoter region CpG islands methylation of (Poly [ADP-ribose] polymerase 1, PARP-1) gene in human HaCaT Cell.

METHODSHaCaT Cells were treated with nm-SiO₂at 0, 2.5, 5 and 10 µg/mL and micro-SiO₂at 10 µg/ml for 24 h and DAC treatment was given at 10 µg/ml group for 48 h. Real-time PCR and western blot assay was used to detect the expression of PARP-1 mRNA and protein. BSP (Bisulfite Pyrosequence, BSP) assay was used to detect the promoter region CpG islands methylation status of PARP-1 gene.

RESULTSAfter exposure to nano-SiO₂particles, compared to CTRL group, the mRNA and protein expression of PARP-1 in micro-SiO₂and 2.5 µg/ml group unchanged, but he mRNA and protein expression of PARP-1 in 5, 10 µg/ml as well as DAC group was down-regulated and there are statistical significance between CTRL group and 5, 10 µg/ml as well as DAC group and the PARP-1 promoter region CpG islands showed methylation.

CONCLUSIONnano-SiO₂can down-regulate PARP-1 expression in HaCaT Cell and this is associated with the change in the methylation of PARP-1 gene promoter region CpG islands induced by nano-SiO₂particles.

Cell Line, Tumor ; CpG Islands ; DNA Methylation ; Humans ; Nanoparticles ; adverse effects ; Poly (ADP-Ribose) Polymerase-1 ; Poly(ADP-ribose) Polymerases ; metabolism ; Promoter Regions, Genetic ; RNA, Messenger ; metabolism ; Silicon Dioxide ; adverse effects

OBJECTIVETo study the potential association of DNA oxidation and DNA methylation, in vitro cultured cells were exposed to different doses of H2O2, 8-oxo-dG formation, cell DNA 5-mC contents were analyzed to explore the time- dose-response relationship of DNA oxidation and DNA methylation.

METHODSA549 cells were exposed to different doses of H2O2, 8-oxo-dG formation and cell genomic DNA 5-mC contents were analyzed by a high-performance liquid chromatography system and high performance capillary electrophoresis (HPCE), respectively.

RESULTSH2O2 induced the formation of 8-oxo-dG and 5-mC in different characteristics, it need at least 10 days for significant changes in the level of DNA methylation, whereas under the same conditions, changes in the level of DNA oxidation cast only 12 hours. H2O2 induced decreased levels of DNA methylation in A549 cells in a dose-dependent manner. In a certain range of time and dose, it showed a negative correlation between DNA oxidation and DNA methylation.

CONCLUSIONThe study suggests that oxidative DNA could lead to reduced levels of DNA methylation, DNA oxidation may affect the regulation of cellular methylation mechanisms, in the course of chemical mutagenesis, DNA oxidation may be an earlier important molecule event than DNA methylation.

Cell Line ; DNA ; chemistry ; DNA Damage ; DNA Methylation ; Deoxyguanosine ; analogs & derivatives ; chemistry ; Humans ; Hydrogen Peroxide ; toxicity ; Oxidative Stress

ObjectiveThe study utilized human transcriptome microarray to explore biomarkers for diagnosing drug-induced liver injury （DILI） caused by anti-tuberculosis drugs. MethodsA 6-month follow-up study was conducted on 152 patients treated with anti-tuberculosis drugs in designated hospitals in Shanghai. The blood samples were collected at the 0， 2， 4， 8， 12 and 24 weeks after treatment. According to the clinical biochemical indicators， the research subjects were divided into DILI cases （34 cases） and Control cases （118 cases）. Single factor analysis was conducted on the influencing factors between the two groups. In a 1∶1 matched DILI-control study， RNA samples of 13 pairs of cases were sequenced by the whole transcript expression mRNA array. Differentially expressed genes （DEGs） were screened by Hotelling's T² value sequencing and the expression trend analysis of genes by STEM （short-time series expression miner）， and the functional enrichment and pathway analysis of DEGs were carried out. ResultsIn total 152 clinical cases， weight of patients was a risk factor for the occurrence of hepatotoxicity caused by anti-tuberculous drugs. Based on the analysis results of mRNA array， 513 DEGs were screened by Hotelling's T² value sequencing method， which were enriched in 32 annotations of GO （Gene Ontology） analysis and 10 pathways of KEGG （Kyoto encyclopedia of genes and genomes） analysis. One differential expression pattern was screened by STEM， which was enriched in 2 biological process notes of GO. Among them， the key genes AIM2， CD86， CXCL10 and non-coding RNAs SCARNA10， SNHG10 and SNORD105 are potential biomarkers of DILI caused by anti-tuberculosis drugs. ConclusionIn this research for biomarkers conducted on cases with liver injury caused by anti-tuberculosis drugs， biological pathways associated with hepatotoxicity are identified and a series of key genes related with drug-induced liver injury are found， which provides the basis for mechanism study and searching for earlier and more sensitive biomarkers.

Background Natural pyrethrins have long been widely used in the fields of environmental and household hygiene. Studies have reported that natural pyrethrins have potential liver toxicity, but their specific mechanisms are still unclear yet. Objective To explore the effect of natural pyrethrins on DNA damage in human liver cells. Methods This study used human liver cell QSG7701 as an in vitro testing model. After exposure to DMSO and a series of concentrations of natural pyrethrins (5, 10, 20, and 40 μg·mL⁻¹) for 6 and 24 h, reactive oxygen species (ROS) was detected by fluorescence microscopy using a fluorescence probe, thiobarbituric acid reactive substance (TBARS) by colorimetric method using a microplate reader, DNA damage by comet assay through observing DNA fragment migration under microscope, and phospho H2AX (γH2AX) and 8-oxoguanine (8-oxoG) by immunofluorescence assay using a laser confocal microscope. Results As the exposure concentration of natural pyrethrins increased, the fluorescence intensity of ROS significantly increased in a concentration-dependent manner. The differences in ROS between the 10 μg·mL⁻¹ and above groups and the control group were statistically significant (P<0.01), and the ROS levels in the 20 μg·mL⁻¹ and 40 μg·mL⁻¹ treatment groups were 2.17 and 3.05 times higher than that in the control group respectively. The TBARS level increased in a concentration-dependent manner in natural pyrethrins treated cells (P<0.01), and the levels in the 20 μg·mL⁻¹ and 40 μg·mL⁻¹ treatment groups were 2.46 and 3.01 times higher than that in the control group respectively. The results of comet assay showed trailing formation of cellular DNA in each dose group; as the exposure concentration of natural pyrethrins increased, indicators such as tail DNA content (TDNA%), tail length (TL), tail moment (TM), and Olive tail moment (OTM) increased in a concentration-dependent manner. Compared with the control group, the differences in the indicators between the 20 μg·mL⁻¹ and above groups and the control group were statistically significant (P<0.01), especially in the 40 μg·mL⁻¹ treatment groups, where TDNA%, TL, TM, and OTM were (46.92 ± 3.52) %, (64.67± 4.16) μm, 30.96 ± 2.94, and 22.64 ± 3.89, respectively. The cellular immunofluorescence results showed that natural pyrethrins induced the formation of γH2AX and 8-oxoG, the fluorescence intensities of γH2AX and 8-oxoG increased in a concentration-dependent manner, and the differences between the 10 μg·mL⁻¹ and above groups and the control group were statistically significant (P<0.01). Conclusion Natural pyrethrins could induce DNA damage in human liver cells, and ROS-mediated oxidative stress may play an important role in its liver cell genotoxicity.

Objective To establish bovine corneal opacity and permeability （BCOP） test， and determine its predictive ability for the eye irritation evaluation of cosmetics. Methods A total of ten reference chemicals were selected to establish the BCOP test. Then eye irritation of 16 routinely collected cosmetics in our laboratory was predicted. In vitro scores were calculated by the change in the opacity and sodium fluorescein permeability after exposure to the testing cosmetics， and subsequently compared with the historical data by Draize test. Results Reference chemicals with known irritation classification were correctly classified by the BCOP test， which was consistent with the classification of UN globally harmonized system of classification and labeling of chemicals. Moreover， the specificity of the BCOP test for the classification of non-irritating cosmetics samples was 80.0% （8/10）， and the sensitivity for weak to mild irritating cosmetics samples was 83.3% （5/6）. The BCOP test demonstrated an overall classification consistency of 81.3% （13/16） with in vivo test. Conclusion BCOP test may be independently used to identify chemicals with potential eye irritation and serious eye damage， suggesting it is significant for in vitro integrated test strategy for predicting eye irritation due to cosmetics.