ABSTRACT
Zika virus (ZIKV) is an emerging mosquito-borne virus that is associated with severe congenital brain malformations in the fetus and Guillain-Barré syndrome in adults. However, there are currently no drugs or preventive vaccines approved for ZIKV infection. Here, ciclesonide has been found significantly against ZIKV activity by plaque and cytotoxicity assays in vitro, and its 50% effective concentration (EC50) to ZIKV SZ01 and MR766 are (0.40 ± 0.22) and (1.59 ± 1.08) μmol·L-1, respectively. Its 50% cytotoxic concentration (CC50) to Vero cells are (64.70 ± 7.33) μmol·L-1; Virus yield reduction and Western blot assays showed that ciclesonide can inhibit replication of ZIKV. In addition, ciclesonide can also inhibit the replication of ZIKV in A549 cells; the results of time of drug addition analysis indicated that ciclesonide mainly acts on the ZIKV RNA synthesis stage. Ciclesonide can also inhibit the internalization of ZIKV. These results indicated that ciclesonide is a potential drug against ZIKV.
ABSTRACT
Tenofovir disoproxil fumarate (TDF) is a nucleoside analogue that has been widely used for clinical treatment of human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infection. The aim of this study was to investigate whether TDF has anti-Zika virus (ZIKV) activity in vitro. The inhibitory effect of TDF on ZIKV was detected by plaque reduction assay. Then, the anti-ZIKV activity of TDF at RNA level and protein level was verified by real time quantitative PCR and Western blot. Finally, MTT assay was used to determine the cytotoxicity of TDF. Our results showed that TDF not only reduced the formation of plaque after ZIKV infection, but also inhibited the replication of ZIKV RNA or expression of ZIKV NS2B protein. The 50% effective concentration (EC50) of TDF in inhibition of ZIKV replication were 14.96-27.47 μmol·L-1, while that of ribavirin was 56.01 ± 12.16 μmol·L-1, which served as the positive control. The cytotoxicity of TDF and ribavirin in Vero cells were very low, with their 50% cytotoxic concentration (CC50) values being greater than 500 μmol·L-1. The therapeutic index of TDF calculated by CC50/EC50 was greater than 18.20, which was significantly higher than that of ribavirin. The results suggest that TDF has good anti-ZIKV activity in vitro and is expected to become a candidate drug for anti-ZIKV therapy.
ABSTRACT
Objective To investigate the effects of DL-3-n-Butylphthalide(NBP)on proliferation and apoptosis of 1-methyl-4-phenyl-pyridinium (MPP +)-induced SH-SY5Y cells, and mechanisms via mixed lineage kinase 3 (MLK3) signaling pathway. Methods The SH-SY5Y cells were divided into control group,MPP+group,NBP group and URMC-099 group,that cultured normally,with 1 mmol/L MPP+for 24 hours,with 10μmol/L NBP for 3 hours and then with MPP+for 24 hours,and with 200 nmol/L MLK3 inhibitor URMC-099 for 3 hours and then with MPP+for 24 hours,respectively.The morphology of SH-SY5Y cells was observed under inverted phase contrast mi-croscope and the survival rate was measured with 3-(4,5-Cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assays.The apoptosis was quantified under flow cytometry with Annexin V/PI fluorescence staining,and the nuclear morphology was observed with Hoechst 33342 staining.The expression of phosphorylated protein of MLK3(p-MLK3),c-Jun N-terminal kinase(p-JNK),extra cellular regulated protein ki-nases(p-ERK1/2)were detected with Western blotting.Results Compared with the control group,the survival rate reduced and apoptosis in-creased in MPP+group(P<0.05),with the increase of p-MLK3 and p-JNK and decrease of p-ERK1/2 d(P<0.05).Compared with MPP+group,the survival rate increased and apoptosis reduced in both NBP and URMC-099 groups(P<0.05),with the decrease of p-MLK3 and p-JNK and increase of p-ERK1/2(P<0.05).Conclusion NBP can decrease the apoptosis and promote the proliferation of SH-SY5Y cells in-duced by MPP+,which may be associated with inhibiting MLK3 signaling pathway,and regulating the downstream p-JNK and p-ERK1/2.
ABSTRACT
Ribavirin is a broad-spectrum antiviral agent and glycyrrhizin has activities of anti-inflammation, immunoregulation and anti-viral infections. To enhance antiviral efficacy and weaken side-effects of ribavirin, antiviral effects of the combination of glycyrrhizin and ribavirin were studied in the present study. Firstly, a mouse model of viral pneumonia was established by inoculation of influenza H1N1 virus. Protective effects of glycyrrhizin and ribavirin used alone or in combination against H1N1 virus infection in mice were evaluated based on the survival rate, lung index and virus titer in lungs of mice. Results showed that the combination of glycyrrhizin and ribavirin significantly inhibited the lung consolidation with a 36% inhibition ratio on the lung swell of infected mice. The combination of the two drugs exhibited synergetic effects on survival of infected mice. The combination of 50 mg · kg(-1) · d(-1) glycyrrhizin and 40 mg · kg(-1) · d(-1) ribavirin resulted a 100% protection for infected mice with a synergetic value of 36, which was significantly higher than the control group and each drug alone. This combination also resulted a significant drop of lung virus titer (P < 0.01), as well as inhibition on the production of proinflammatory cytokines IL-6 (P < 0.01), TNF-α (P < 0.01) and IL-1β (P < 0.05) induced by virus infection compared to the control. The treatment of ribavirin plus glycyrrhizin was more effective in influenza A infection in mice than either compound used alone, which suggested a potential clinical value of the combination of the two agents.