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1.
Viruses ; 13(8)2021 08 23.
Article in English | MEDLINE | ID: covidwho-1524167

ABSTRACT

The pandemic of COVID-19 caused by SARS-CoV-2 continues to spread despite the global efforts taken to control it. The 3C-like protease (3CLpro), the major protease of SARS-CoV-2, is one of the most interesting targets for antiviral drug development because it is highly conserved among SARS-CoVs and plays an important role in viral replication. Herein, we developed high throughput screening for SARS-CoV-2 3CLpro inhibitor based on AlphaScreen. We screened 91 natural product compounds and found that all-trans retinoic acid (ATRA), an FDA-approved drug, inhibited 3CLpro activity. The 3CLpro inhibitory effect of ATRA was confirmed in vitro by both immunoblotting and AlphaScreen with a 50% inhibition concentration (IC50) of 24.7 ± 1.65 µM. ATRA inhibited the replication of SARS-CoV-2 in VeroE6/TMPRSS2 and Calu-3 cells, with IC50 = 2.69 ± 0.09 µM in the former and 0.82 ± 0.01 µM in the latter. Further, we showed the anti-SARS-CoV-2 effect of ATRA on the currently circulating variants of concern (VOC); alpha, beta, gamma, and delta. These results suggest that ATRA may be considered as a potential therapeutic agent against SARS-CoV-2.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus 3C Proteases/antagonists & inhibitors , SARS-CoV-2/drug effects , Tretinoin/pharmacology , Animals , Cell Line, Tumor , Chlorocebus aethiops , Cysteine Proteinase Inhibitors/pharmacology , DEAD Box Protein 58/metabolism , High-Throughput Screening Assays , Humans , Receptors, Immunologic/metabolism , SARS-CoV-2/enzymology , SARS-CoV-2/physiology , Vero Cells , Virus Replication/drug effects
2.
Viruses ; 13(2)2021 02 15.
Article in English | MEDLINE | ID: covidwho-1085038

ABSTRACT

To predict the clinical outcome of coronavirus disease-2019 (COVID-19), we examined relationships among epidemiological data, viral load, and disease severity. We examined viral loads of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) in fatal (15 cases), symptomatic/survived (133 cases), and asymptomatic cases (138 cases) using reverse transcription quantitative real-time PCR (RT-qPCR). We examined 5768 nasopharyngeal swabs (NPS) and attempted to detect the SARS-CoV-2 genome using RT-qPCR. Among them, the viral genome was detected using the method for the 370 NPS samples with a positive rate of 6.4%. A comparison of each age showed that the fatal case was higher than the survived case and asymptomatic patients. Survived cases were older than asymptomatic patients. Notably, the viral load in the fatal cases was significantly higher than in symptomatic or asymptomatic cases (p < 0.05). These results suggested that a high viral load of the SARS-CoV-2 in elderly patients at an early stage of the disease results in a poor outcome. We should, therefore, intervene early to prevent a severe stage of the disease in such cases.


Subject(s)
COVID-19/diagnosis , Nasal Mucosa/virology , SARS-CoV-2/isolation & purification , Viral Load , Adult , Aged , COVID-19/virology , Female , Humans , Japan , Male , Middle Aged , RNA, Viral/analysis , Severity of Illness Index
3.
Internal Medicine ; 127(1):95-97, 2021.
Article in Japanese | ISHO-JP | ID: covidwho-994593

ABSTRACT

Summary Vaccine development is important for the control of COVID-19, as well as for the development of diagnostic and therapeutic agents, and vaccine development is underway in many countries. Vaccine development is underway in many countries. Although there is no vaccine with established efficacy, phase III trials have begun in the United Kingdom, the United States, China, Russia, and Germany. The development of inactivated vaccines such as DNA vaccines, RNA vaccines, and vector vaccines is underway. There have been reports that BCG vaccine is expected to be effective, but the efficacy has not yet been established. Rapid vaccine development is required, and attention should be paid to issues such as adverse events and duration of efficacy.

4.
Microorganisms ; 8(10)2020 Oct 20.
Article in English | MEDLINE | ID: covidwho-890391

ABSTRACT

Favipiravir was initially developed as an antiviral drug against influenza and is currently used in clinical trials against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection (COVID-19). This agent is presumably involved in RNA chain termination during influenza virus replication, although the molecular interactions underlying its potential impact on the coronaviruses including SARS-CoV-2, SARS-CoV, and Middle East respiratory syndrome coronavirus (MERS-CoV) remain unclear. We performed in silico studies to elucidate detailed molecular interactions between favipiravir and the SARS-CoV-2, SARS-CoV, MERS-CoV, and influenza virus RNA-dependent RNA polymerases (RdRp). As a result, no interactions between favipiravir ribofuranosyl-5'-triphosphate (F-RTP), the active form of favipiravir, and the active sites of RdRps (PB1 proteins) from influenza A (H1N1)pdm09 virus were found, yet the agent bound to the tunnel of the replication genome of PB1 protein leading to the inhibition of replicated RNA passage. In contrast, F-RTP bound to the active sites of coronavirus RdRp in the presence of the agent and RdRp. Further, the agent bound to the replicated RNA terminus in the presence of agent, magnesium ions, nucleotide triphosphate, and RdRp proteins. These results suggest that favipiravir exhibits distinct mechanisms of action against influenza virus and various coronaviruses.

5.
J Allergy Clin Immunol ; 146(2): 330-331, 2020 08.
Article in English | MEDLINE | ID: covidwho-597639
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