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Objective To investigate the uptake mechanism of HepG2.2.15 cells to the nanoparticles co-loaded with syringopicroside and hydroxytyrosol (SH-NPs). Methods The nanoparticles were prepared by using a nanoprecipitation method with mPEG-PLGA as nano-carrier co-loaded with syringopicroside and hydroxytyrosol. The uptake mechanism of HepG2.2.15 cells to SH-NPs was studied by fluorescence microscopy and flow cytometry using fluoresceineisothiocyanate (FITC) as a fluorescent marker. Results With colchicine as the inhibitor, the incubation time ranged from 0.5 to 24 h, the percentage of positive cells increased from 1.9% to 56.4%; When the drug concentration was 125, 250 μg/mL and 500 μg/mL, the positive cell percentages were 4.9%, 3.4% and 3.9%. With chloroquine as the inhibitor; the incubation time ranged from 0.5 to 24 h, the percentage of positive cells increased from 7.4% to 55.4%; When the drug concentration was 125, 250 and 500 μg/mL, the percentage of positive cells was 19.5%, 22.5% and 27.6%. Conclusion Colchicine and chloroquine have an inhibitory effect on HepG2.2.15 cells uptake, and the uptake of SH-NPs in HepG2.2.15 cells was positively correlated with drug concentration and incubation time. It can be concluded that the uptake mechanism of HepG2.2.15 cells to SH-NPs was nonspecific adsorption endocytosis.
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Objective To observe whether the classic drug-resistant mutations can be induced in various concentrations of adefovir (ADV)-treated HepG2.2.15 cells persistently and explore the mechanism for emergence of drug resistance.Methods HepG2.2.15 cells were cultured continually in 12-well plates with medium containing 0,0.01,0.1,1.0μmol/L concentration of ADV,and passaged every 3 days up to the 110th generations.The intracellular and supernatant HBV DNA was extracted every 10 generations.Intracellular HBV cccDNA was amplified by plasmid-safe ATP dependent DNase (PSAD) digestion in combination with rolling circle amplification and gap-spanning semi-nested PCR assay.And the RT region of supernatant HBV DNA was amplified by one-tube nested PCR assay.Then the classic drug-resistant mutations of the RT region of intracellular cccDNA and supernatant HBV DNA were analyzed using direct PCR sequencing combined with clonal sequencing (more than 20 clones/sample).Results HBV DNA stably replicated in ADV-untreated cells (control group).The intracellular total DNA and cccDNA levels,supernatant HBV DNA level decreased continuously with the prolonged ADV culture duration in 0.01 μmol/L and 0.1μmol/L ADV group.Drug resistant mutations were not detected up to the 110th generation in 0.01 μmol/L ADV group;while rtA181V+N236T mutations were detected at the110th generation in 0.1μmol/L ADV group.The 1.0μmol/L ADV group was ceased of culture at the 15th generation due to inhibited cell growth.Conclusion HBV cccDNA exists in HepG2.2.15 cells,and the classical drug-resistant mutations of rtA181V+N236T could be induced by proper concentration of ADV.
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To investigate the antiviral effect of thymopolypeptides combined with 4 kinds of matrine type alkaloids on HepG2.2.15 cells, oxymatrine, sophocarpidine, sophocarpine, and sophoridine (at concentration of 0.2 mmol•L⁻¹ respectively) were respectively combined with thymopolypeptides (0.025, 0.1 g•L⁻¹), and after 48 h and 72 h treatment on HepG2.2.15 cells, the cells and supernatants were collected. The cells activity in various groups was determined by CCK-8 method to evaluate the toxic effects of the drugs on HepG2.2.15 cells. Enzyme linked immunosorbent assay (ELISA) was used to determine HBeAg and HBsAg levels in cellular supernatants. HBV DNA levels in cellular supernatants andcells were quantified with fluorogenic quantitative PCR method; and the expression level of IFN-α in supernatants was detected with CBA method. The results indicated that single thymopolypeptides at 0.025-0.4 g•L⁻¹ had no toxicity to cells. Thymopolypeptides in this concentration range combined with 0.2 mmol•L⁻¹ matrine type alkaloids also had no toxicity to cells. Anti-HBV activity of drug combination was better than that of alkali or thymopolypeptides alone. Thymopolypeptides at 0.025 g•L⁻¹ had better inhibitory effect than thymopolypeptides at 0.1 g•L⁻¹ on intracellular HBV DNA expression, but the inhibitory effect on supernatant HBeAg level was on the contrary. Anti-HBV activity was similar between alkaloids combined with 0.1 g•L⁻¹ and alkaloids combined with 0.025 g•L⁻¹. There was no statistical difference in anti-HBV effect between various combined groups (P<0.05). In general, 72 h anti-HBV effect was better than 48 h anti-HBV effect (P<0.05). The expression of IFN-α was increased after drug combination, with positive correlation to the changes of other four indicators (P<0.05). In conclusion, oxymatrine, sophocarpidine, sophocarpine and sophoridine combined with thymopolypeptides could inhibit HBsAg and HBeAg secretion in HepG2.2.15 cells and HBV DNA replication, and further promote the antiviral effect by promoting the expression of IFN-α.
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MTT assay was used in this study to investigate the inhibitory effect of danshensu on the activity of 2.2.15 cells among human hepatoma cell line (HepG2); indirect fluorescence labeling method was used to measure the changes of reactive oxygen levels in the cells; ELISA method was used to determine hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) levels in cellular supernatants; HBV DNA level was measured with fluorogenic quantitative PCR method. The inhibitory effect of danshensu on HBV RT(hepatitis B virus reverse transcriptase) was studied by using enzyme inhibition dynamics, and the effect of danshensu on secondary structure of HBV reverse transcriptase was monitored by using circular dichroism. The results showed that danshensu had a good inhibitory effect on the growth of HepG2.2.15 cells, with a half inhibitory concentration (IC₅₀) of (15.35±2.43) μmol•L⁻¹; danshensu could significantly inhibit HBsAg and HBeAg expressions, and showed an inhibitory effect on HBV DNA replication. In addition, danshensu was an effective inhibitor for HBV reverse transcriptase [IC₅₀ (21.32±2.43) μmol•L⁻¹]. The fluorescence labeling results showed that the reactive oxygen levels in the cells were increased with the increase of danshensu concentration. Circular dichroism analysis showed that danshensu could induce partial change of conformation of HBV reverse transcriptase and gradually increased α-helical content. These results indicated that danshensu could make the structure of the enzyme become closer by binding to HBV reverse transcriptase, which was not conducive to the formation of the active center, so it could finally decrease the activity of HBV reverse transcriptase. Such decrease in enzyme activity would directly affect the HBV DNA replication, and combined with the decrease of the antigen levels, the effect of danshensu on HBV was increased.
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Objective To construct the miRNA‐21 eukaryotic overexpression vector pmR‐21 and to explore its regulation effect on the expression of c‐myc gene in HepG2 .2 .15 cells .Methods The miRNA‐21 precursor gene fragment pre‐miRNA‐21 was amplified by PCR ,then connected to the pmR‐mCherry plasmid vector after double enzyme digestion ,the accuracy of the recombi‐nant vector was verified by double enzyme digestion and sequencing ;then the recombinant vector was transfected into HepG2 .2 .15 cells ,the fluorescent protein expression was observed under the fluorescence microscopy at 24 h and the transfection efficiency was detected by flow cytometry ;the expression of miRNA‐21 was evaluated by real‐time quantitative PCR;at 72 h after transfection ,the expression levels of c‐myc gene were detected by RT‐PCR and Western blot ;CCK‐8 was used to detect the cell proliferation in each group .Results The double enzyme digestion and Western blot verified that the target gene fragment was inserted into the pmR‐mCherry vector;at 24 h after transfection ,intracellular strong fluorescence was seen ,the transfection efficiency was higher than 50% ;miRNA‐21 expression level of the pmR‐21 recombinant vector group was significantly increased;c‐myc gene expression was increased in the pmR‐21 recombinant vector group at 72 h after transfection ,the cell proliferation in the pmR‐21 recombinant group was faster than that in the control group(P<0 .05) .Conclusion The pmR‐21 eukaryotic overexpression vector is successfully con‐structed ,this recombinant vector can express miRNA‐21 stably ;miRNA‐21 can up‐regulate c‐myc gene expression ,c‐myc gene is one of miR‐21′s targets for playing a cancer‐promoting action .
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AIM:To investigate the effects of xeroderma pigmentosum D ( XPD) and p53 on the replication of hepatitis B virus ( HBV) .METHODS:Recombinant plasmid pEGFP-N2/XPD and vacant vector plasmid pEGFP-N2 were transfected into HepG2.2.15 cells by liposome.On the next day, these cells were incubated with pifithrin-α, a p53 inhibi-tor, at a concentration of 20 μmol/L for 24 h.The cells were divided into 5 groups: blank control group, pEGFP-N2 group, pEGFP-N2/XPD group, pEGFP-N2/XPD+pifithrin-αgroup and pifithrin-αgroup.The mRNA expression of XPD, hepatitis B surface antigen ( HBsAg) , hepatitis B e antigen ( HBeAg) and hepatitis B virus X protein ( HBx) was detected by RT-PCR.The content of HBsAg and HBeAg in the supernatants of culture medium was measured by ELISA.The con-tent of HBV-DNA in the supernatants of culture medium was examined by fluorescence quantitative PCR.Using the method of bDNA, the content of HBV-DNA in the core particles was assessed.RESULTS:The expression of XPD mRNA was ele-vated by the transfection of recombinant plasmid pEGFP-N2/XPD.The increase in XPD expression significantly down-regu-lated the mRNA expression of HBsAg, HBeAg and HBx.The content of HBsAg and HBeAg in the supernatants of culture medium was significantly decreased by the increase in XPD expression.The results of fluorescence quantitative PCR showed that the content of HBV-DNA in the supernatants of culture medium was significantly down-regulated by the increase in XPD expression.bDNA results showed that the content of HBV-DNA in the core particles was significantly decreased by the increase in XPD expression.Pifithrin-αabolished the above-mentioned effects of XPD (all P<0.01).CONCLUSION:XPD inhibits the replication of HBV through p53 pathway.Therefore, XPD and p53 may be the targets for antiviral therapy of hepatitis B.
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Objective To investigate the effects of HBcAg-specific CD8+T cells on inhibiting HBV replication in vitro,and to search the cytokine of noncytolytic mechanisms in viral clearance. Methods By the method of coculture of HepG2.2.15 cell (target cells) with HLA-A2 matched HBcAg-specific CD8+T cell clone (effector cells) at E:T ratios of 1:50,and monitoring HBV production (HBsAg,HBeAg,and HBV-DNA)in coculture supernatants at 24h,48h and 72h,the percentage of decrease in HBV replication level was observed. Furthermore,blocking experiment with neutralizing mAbs to IFN-? was performed to evaluate the effect of this cytokine. Results CD8+T clone produced high levels of IFN-?following coculture with 2.2.15 cells. HBsAg,HBeAg and HBV-DNA in coculture supernatants were significantly reduced,and the greatest effect was observed at 72h by 54.55%,50.36% and 74.55%,respectively. The reduction of HBV DNA was decreased followed by using neutralizing mAbs to IFN-?. The maximum activity of cytotoxicity of target cells was at 24h by 15.66%. Conclusion ①HBV-specific CD8+T cells inhibit HBV replication by cytolytic and noncytolytic mechanisms.②The effect of noncytolytic mechanisms is mainly mediated by IFN-?.
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AIM: To investigate the effect of mycophenolate acid(MPA) on hepatitis B virus(HBV) replication in vitro.METHODS: In the presence or absence of guanosine,the HepG2.2.15 cells were treated with different concentrations of MPA(1-20 mg/L) for 4 days.Hepatitis B surface antigen(HBsAg) and hepatitis Be antigen(HBeAg) in supernatant were detected by ELISA.Intracellular HBV core mRNA and HBV DNA were analyzed by reverse transcription-polymerase chain reaction(RT-PCR) and slot blot hybridization,respectively.RESULTS: MPA suppressed the expression of HBsAg and HBeAg,and inhibited the replication of HBV DNA.The effect of MPA on HBV replication was reversed by addition of exogenous guanosine.CONCLUSION: MPA suppresses the expression of HBsAg,HBeAg and replication of HBV DNA in HepG2.2.15 cells.Reducing the synthesis of guanosine nucleotides may be involved in the mechanism of the inhibitory activity of MPA on HBV replication.
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Objective In order to explore the roles of TLR2 and TLR4 in the hepatocyte dam- age caused hy hepatitis B virus infection,and to find whether LPS can affect the damage of hepato- cytes pre-and pos-HBV infection,we detected the changes of TLR2 and TLR4 expressions in hu- man hepatocyte lines HepG2 cells and 2.2.15 cells.Methods HepG2 ceils are most similar to normal human hepatocytes and 2.2.15 ceils are HepG2 cells infected with HBV.We selected these two cell lines to study the differences of TLR2 and TLR4 expression between HepG2 cells before and after HBV infection.In this research,both HepG2 and 2.2.15 cells were stimulated with 0?g/ml, 1?g/ml,10?g/ml,100?g/ml,1 mg/ml and 10 mg/ml LPS.Then the expression of protein of TLR2 and TLR4 were examined by immuno-histochemistry(IHC).The cnRNA of HepG2 and 2.2.15 ceils stimulated with 0?g/ml and 10 mg/ml LPS were examined by reversal transcription-pol- ymerase chain reaction(RT-PCR).Thereafter,the apoptosis of HepG2 and HepG2.2.15 cells were examined by flow cytometry(FC),and the expressions of HBsAg and HBeAg of HepG2.2.15 cells tested with Abbott kits.Results IHC and RT-PCR analysis revealed that TLR2 and TLR4 expres- sions could he detected in both HepG2 and 2.2.15 cells.Moreover,without immune activation, TLR2 and TLR4 expressions were higher in the presence of higher concentrations of LPS.FC analy sis revealed that no apoptosis detected in HepG2 ceils stimulated with LPS in this research,but apop- tosis could be detected in 2.2.15 cells when treated with the same factors.Furthermore,the apoptosis ratios increased with the increase of LPS concentrations.When concentrations of LPS were 1?g/ml, 10?g/ml,100?g/ml,1 mg/ml and 10 mg/ml,the apoptosis ratios were 1.94%,3.03%,3.50%, 3.72%,5.30%,respectively.Abbott analysis revealed that expressions of HBsAg and HBeAg of 2.2.15 cells stimulated with LPS were lower than those not stimulated with LPS.Conclusion HBV can affect the expressions of TLR2 and TLR4 in HepG2 cell lines.LPS can lead 2.2.15 cells to apop- tosis but not HepG2 cells.Although LPS cannot damage normal hepatocytes,it might aggravate hep- atocytes damage when their microenvironment was changed by HBV infection.
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AIM:To study the inhibitory effect of Compound Liuyuexue(Tarphochlamys affinis(Giff) Bremekhu,Herba Hedyotis,Raidx Gardeniae,etc.)(CLYX) on HBV in vitro.METHODS:The serum containing CLYX was added to cultured HepG2.2.15 cells,and HepG2.2.15 cells were cultured in medium containing the serum with CLYX for 72 h and 144 h.The culture media were collected for determining the levels of HBsAg and HBeAg by ELISA.RESULTS:The serum containing CLYX could markedly inhibit HBsAg and HBeAg expressions in the HepG2.2.15 cells(P