SARS-CoV-2 replicon for high-throughput antiviral screening.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus, which is highly pathogenic and classified as a biosafety level 3 (BSL-3) agent, has greatly threatened global health and efficacious antivirals are urgently needed. The high requirement of facilities to manipulate the live virus has limited the development of antiviral study. Here, we constructed a reporter replicon of SARS-CoV-2, which can be handled in a BSL-2 laboratory. The Renilla luciferase activity effectively reflected the transcription and replication levels of the replicon genome. We identified the suitability of the replicon in antiviral screening using the known inhibitors, and thus established the replicon-based high-throughput screening (HTS) assay for SARS-CoV-2. The application of the HTS assay was further validated using a few hit natural compounds, which were screened out in a SARS-CoV-2 induced cytopathic-effect-based HTS assay in our previous study. This replicon-based HTS assay will be a safe platform for SARS-CoV-2 antiviral screening in a BSL-2 laboratory without the live virus.

Generation and characterization of Japanese encephalitis virus expressing GFP reporter gene for high throughput drug screening.

Japanese encephalitis virus (JEV), a major cause of Japanese encephalitisis, is an arbovirus that belongs to the genus Flavivirus of the family Flaviviridae. Currently, there is no effective drugs available for the treatment of JEV infection. Therefore, it is important to establish efficient antiviral screening system for the development of antiviral drugs. In this study, we constructed a full-length infectious clone of eGFP-JEV reporter virus by inserting the eGFP gene into the capsid-coding region of the viral genome. The reporter virus RNA transfected-BHK-21 cells generated robust eGFP fluorescence signals that were correlated well with viral replication. The reporter virus displayed growth kinetics similar to wild type (WT) virus although replicated a little slower. Using a known JEV inhibitor, NITD008, we demonstrated that the reporter virus could be used to identify inhibitors against JEV. Furthermore, an eGFP-JEV-based high throughput screening (HTS) assay was established in a 96-well format and used for screening of 1443 FDA-approved drugs. Sixteen hit drugs were identified to be active against JEV. Among them, five compounds which are lonafarnib, cetylpyridinium chlorid, cetrimonium bromide, nitroxoline and hexachlorophene, are newly discovered inhibitors of JEV, providing potential new therapies for treatment of JEV infection.

Development of a rapid antiviral screening assay based on eGFP reporter virus of Mayaro virus.

Mayaro virus (MAYV) is a neglected mosquito-borne alphavirus that causes illness similar to Chikungunya (CHIKV), Dengue (DENV) and Zika virus (ZIKV). Currently, there is no specific treatment or vaccine against MAYV infection. To develop an efficient antiviral screening assay for MAYV, we constructed the infectious clones of MAYV strain BeAr 20290 and its eGFP reporter virus. The reporter virus exhibited high replication capacity indistinguishable with the wild type MAYV, and was genetically stable within at least five rounds of passages in BHK-21 cell. The expression of eGFP correlated well with the viral replication. Using the known inhibitor ribavirin, we confirmed that the MAYV-eGFP reporter virus could be used for antiviral screening to identify the specific inhibitors against MAYV. Using the MAYV-eGFP based antiviral assay, we found that the compound 6-Azauridine which had antiviral activity against CHIKV and SFV, showed a significant inhibitory effect on MAYV replication.

[Research about effect of spray drying conditions on hygroscopicity of spray dry powder of gubi compound's water extract and its mechanism].

OBJECTIVE: To investigate moisture content and hygroscopicity of spray dry powder of Gubi compound's water extract obtained at different spray drying conditions and laying a foundation for spray drying process of Chinese herbal compound preparation. METHOD: In the paper, on the basis of single-factor experiments, the author choose inlet temperature, liquid density, feed rate, air flow rate as investigated factors. RESULT: The experimental absorption rate-time curve and scanning electron microscopy results showed that under different spray drying conditions the spray-dried powders have different morphology and different adsorption process. CONCLUSION: At different spray-dried conditions, the morphology and water content of the powder is different, these differences lead to differences in the adsorption process, at the appropriate inlet temperature and feed rate with a higher sample density and lower air flow rate, in the experimental system the optimum conditions is inlet temperature of 150 degrees C, feed density of 1.05 g x mL(-1), feed rate of 20 mL x min(-1) air flow rate of 30 m3 x h(-1).

[Effect of Qianlie Huichun on prostate tissue VEGF expression in rats].

OBJECTIVE: To investigate the effect of Qianlie Huichun on the expression of vascular endothelial growth factor(VEGF) in prostate tissues and expound its anti-prostatomegaly action in model rats with prostatic hypertrophy induced by injected testosterone. METHODS: A total of 60 male rats were eventy randomized into six groups. All were gelded except the normal control group. After a week, the gelded rats were injected with testosterone(4 mg/kg/d), meanwhile the first group were fed with a small dosage of Qianlie Huichun(0.4 g/kg/d), the second group with a medium dosage(0.8 g/kg/d), the third group with a large dosage(1.6 g/kg/d), and the fourth group injected with estriol(2.5 mg/kg/d), all for a month. The fifth group were model controls, and the sixth the normal controls, both fed with the same amount of pure water for a month. Then all the six groups of rats were killed and their prostate glands were resected for the examination of the expression rate of VEGF by immunohistochemical method. RESULTS: The difference of VEGF expression between Qianlie Huichun groups and the model group was significant(P < 0.01), and so was it between the medium and large dosage middle, large amount of Qianlie Huichun groups and the estriol group(P < 0.01). CONCLUSION: Qianlie Huichun depressed the VEGF expression of the prostate gland in model rats, and the expression rate decreased with the increased amount of the drug, which shows that Qianlie Huichun has a definite therapeutic effect on prostatic hypertrophy by depressed the vascular growth of the vessel in the prostate gland.

[Effect of qianlie huichun capsular on Fas expression and cell apoptosis of prostate gland tissue in rat].

OBJECTIVE: To investigate the effect of Qianlie Huichun capsular on Fas expression and cell apoptosis of prostate gland tissue in the model rat. METHOD: Hypertrophy of prostate model rat was established by injecting testosterone to gelding male rats. After being treated with Qianlie Huichun ig 30 days, the rats were killed and prostate glands were resected for examination. The Fas expression was examined by immunobistochemical SABC. The cell apoptosis and the peak of cell apoptosis in the prostate gland of the rats were examined by flow cytometry. Compared with model group, the weight of prostage gland tissue in groups treated with Qianlie Huichun capsular was light (P < 0.01). RESULT: Compared with model group, the Fas expression in all treatment groups increase(P < 0.05, P < 0.01). Compared with normal and model groups, cell apoptosis in all treatment groups increase at different level(P < 0.01). CONCLUSION: The Qianlie Huchun capsular increases the Fas expression and cell apoptosis of model rats, and shows a definite treatment effect on the hypertrophy of prostate by promoting the apoptosis of prostate cell.