Establishment of a cell-based screening assay for inhibitors of SARS-CoV-2 3CL protease / 药学学报

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the pathogen that caused the global COVID-19 outbreak. The 3C-like protease (3CLpro) of SARS-CoV-2 plays a key role in virus replication and has become an ideal target for antiviral drug design. In this paper, we report the validation and use of bioluminescence resonance energy transfer (BRET) technology to establish a cell-based assay for screening for SARS-CoV-2 virus 3CL protease inhibitors. The results show that the method is able to monitor the cleavage efficiency of 3CL protease with good reproducibility (Z' factor is 0.59), and is consistent with antiviral activity analysis in cell culture. This work demonstrates that this method can be applied to the screening and evaluation of 3CL protease inhibitors, providing a powerful tool for the development of new drugs.

Application of Mycobacterium marinum infected zebrafish for evaluation of anti-tuberculosis drugs / 药学学报

Tuberculosis (TB) is a serious infectious disease caused by Mycobacterium. tuberculosis. In recent years, with the emergence of drug-resistant forms, the development of new anti-tuberculosis drugs is urgently needed. In this study, we used Mycobacterium marinum (M. marinum), which is highly similar to M. tuberculosis, to establish a M. marinum infected-zebrafish model and quantitative PCR (qPCR) method for bacterial count analysis. The results showed that injecting M. marinum into the yolk sac is an efficient and convenient way to infect zebrafish embryos. By counting the survival rate of infected zebrafish and the number of bacteria in zebrafish by Ziehl-Neelsen staining, we analyzed the efficacy of isoniazid and rifampicin as anti-tuberculosis drugs and the synergistic effect of drugs. The results suggested that three evaluation methods exhibit good consistency. This study demonstrated that zebrafish-M. marinum infection model combined with qPCR analysis is a simple and efficient method for in vivo screening and evaluation of anti-tuberculosis drugs. Animal experiments were carried out in accordance with the provisions for animal ethics in the Regulations on Laboratory Animals of Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences.

The sensitivity of transmitted/founder HIV-1 to anti-HIV drugs / 药学学报

The majority of mucosal HIV-1 infection is initially established by a few HIV-1 viral variants, followed by the development of overt systemic infection, and these viral variants are known as transmitted/founder viruses (T/F viruses). Investigation of the sensitivity of T/F virus to different anti-HIV-1 drugs will provide the best strategies of pre-exposure prophylaxis (PrEP) for high-risk groups of HIV-infected patients. Herein we constructed for the first time, a luciferase reporter system for HIV-1 T/F viruses, and then compared the drug sensitivity between T/F viruses and chronic infection virus. The result showed that the 50% inhibitory concentration (IC50) of nucleoside reverse transcriptase inhibitors (NRTIs), integrase inhibitors (INIs) and protease inhibitors (PIs) were not significantly different between the T/F viruses and chronic infection viruses of the same subtype (P>0.05), while non-nucleoside reverse transcriptase inhibitors (NNRTIs) showed a moderate resistance to T/F viruses, with a significant increase in IC50 (P<0.05). The conclusion suggests that when patients are in high-risk or in the acute infection of HIV-1, NNRTIs should be avoided in the first-line antiretroviral therapy regimens.