Development of Highly Potent Noncovalent Inhibitors of SARS-CoV-2 3CLpro.

The 3C-like protease (3CLpro) is an essential enzyme for the replication of SARS-CoV-2 and other coronaviruses and thus is a target for coronavirus drug discovery. Nearly all inhibitors of coronavirus 3CLpro reported so far are covalent inhibitors. Here, we report the development of specific, noncovalent inhibitors of 3CLpro. The most potent one, WU-04, effectively blocks SARS-CoV-2 replications in human cells with EC50 values in the 10-nM range. WU-04 also inhibits the 3CLpro of SARS-CoV and MERS-CoV with high potency, indicating that it is a pan-inhibitor of coronavirus 3CLpro. WU-04 showed anti-SARS-CoV-2 activity similar to that of PF-07321332 (Nirmatrelvir) in K18-hACE2 mice when the same dose was administered orally. Thus, WU-04 is a promising drug candidate for coronavirus treatment.

Development of Highly Potent Noncovalent Inhibitors of SARS-CoV-2 3CLpro

The 3C-like protease (3CLpro) is an essential enzyme for the replication of SARS-CoV-2 and other coronaviruses and thus is a target for coronavirus drug discovery. Nearly all inhibitors of coronavirus 3CLpro reported so far are covalent inhibitors. Here, we report the development of specific, noncovalent inhibitors of 3CLpro. The most potent one, WU-04, effectively blocks SARS-CoV-2 replications in human cells with EC50 values in the 10-nM range. WU-04 also inhibits the 3CLpro of SARS-CoV and MERS-CoV with high potency, indicating that it is a pan-inhibitor of coronavirus 3CLpro. WU-04 showed anti-SARS-CoV-2 activity similar to that of PF-07321332 (Nirmatrelvir) in K18-hACE2 mice when the same dose was administered orally. Thus, WU-04 is a promising drug candidate for coronavirus treatment. A novel oral noncovalent inhibitor of 3C-like protease, named WU-04, was developed as a promising drug candidate for COVID-19 treatment.

BRET-Based Self-Cleaving Biosensors for SARS-CoV-2 3CLpro Inhibitor Discovery.

The 3C-like protease (3CLpro) of SARS-CoV-2 is an attractive drug target for developing antivirals against SARS-CoV-2. A few small molecule inhibitors of 3CLpro are in clinical trials for COVID-19 treatments, and more inhibitors are under development. One limiting factor for 3CLpro inhibitors development is that the cellular activities of such inhibitors should be evaluated in Biosafety Level 3 (BSL-3) laboratories. Here, we design DNA-coded biosensors that can be used in BSL-2 laboratories to set up cell-based assays for 3CLpro inhibitor discovery. The biosensors were constructed by linking a green fluorescent protein (GFP2) to the N-terminus and a Renilla luciferase (RLuc8) to the C-terminus of SARS-CoV-2 3CLpro, with the linkers derived from the cleavage sequences of 3CLpro. After overexpression of the biosensors in human embryonic kidney (HEK) 293T cells, 3CLpro can be released from GFP2 and RLuc by self-cleavage, resulting in a decrease of the bioluminescence resonance energy transfer (BRET) signal. Using one of these biosensors, pBRET-10, we evaluated the cellular activities of several 3CLpro inhibitors. These inhibitors restored the BRET signal by blocking the proteolysis of pBRET-10, and their relative activities measured using pBRET-10 were consistent with their previously reported anti-SARS-CoV-2 activities. We conclude that the biosensor pBRET-10 is a useful tool for SARS-CoV-2 3CLpro inhibitor discovery. IMPORTANCE The virus proteases 3CLpro are validated drug targets for developing antivirals to treat coronavirus diseases, such as COVID-19. However, the development of 3CLpro inhibitors relies heavily on BSL-3 laboratories. Here, we report a series of BRET-based self-cleaving biosensors that can be used to set up cell-based assays to evaluate the cell permeability and cellular activity of SARS-CoV-2 3CLpro inhibitors in BSL-2 laboratories. The cell-based assay is suitable for high-throughput screening for 3CLpro inhibitors because of the simplicity and good reproducibility of our biosensors. The design strategy can also be used to design biosensors for other viral proteases for which the activation processes involve the self-cleavage of polyproteins.

Histone demethylase LSD1 promotes RIG-I poly-ubiquitination and anti-viral gene expression.

Under RNA virus infection, retinoic acid-inducible gene I (RIG-I) in host cells recognizes viral RNA and activates the expression of type I IFN. To investigate the roles of protein methyltransferases and demethylases in RIG-I antiviral signaling pathway, we screened all the known related enzymes with a siRNA library and identified LSD1 as a positive regulator for RIG-I signaling. Exogenous expression of LSD1 enhances RIG-I signaling activated by virus stimulation, whereas its deficiency restricts it. LSD1 interacts with RIG-I, promotes its K63-linked polyubiquitination and interaction with VISA/MAVS. Interestingly, LSD1 exerts its function in antiviral response not dependent on its demethylase activity but through enhancing the interaction between RIG-I with E3 ligases, especially TRIM25. Furthermore, we provide in vivo evidence that LSD1 increases antiviral gene expression and inhibits viral replication. Taken together, our findings demonstrate that LSD1 is a positive regulator of signaling pathway triggered by RNA-virus through mediating RIG-I polyubiquitination.

Dynamical Variations of the Global COVID-19 Pandemic Based on a SEICR Disease Model: A New Approach of Yi Hua Jie Mu.

The ongoing coronavirus disease 2019 (COVID-19) pandemic has caused more than 150 million cases of infection to date and poses a serious threat to global public health. In this study, global COVID-19 data were used to examine the dynamical variations from the perspectives of immunity and contact of 84 countries across the five climate regions: tropical, arid, temperate, and cold. A new approach named Yi Hua Jie Mu is proposed to obtain the transmission rates based on the COVID-19 data between the countries with the same climate region over the Northern Hemisphere and Southern Hemisphere. Our results suggest that the COVID-19 pandemic will persist over a long period of time or enter into regular circulation in multiple periods of 1-2 years. Moreover, based on the simulated results by the COVID-19 data, it is found that the temperate and cold climate regions have higher infection rates than the tropical and arid climate regions, which indicates that climate may modulate the transmission of COVID-19. The role of the climate on the COVID-19 variations should be concluded with more data and more cautions. The non-pharmaceutical interventions still play the key role in controlling and prevention this global pandemic.

Assessment and modeling of maize evapotranspiration and yield with plastic and biodegradable film mulch

• In wet year, the ET under no film mulching was lower than film mulching, but was higher in dry year. • A slight T difference under BFM and PFM occurred in the late crop growth stages. • Max E difference at B station and J station happen in early and late growth stages, respectively. • Water use efficiency and irrigation use efficiency under PFM and BFM were improved. Biodegradable film mulching (BFM) in various crops is a good alternative to plastic film mulching (PFM). However, the difference in field water consumption between BFM and PFM has not been fully investigated. A four-year experiment with an improved evapotranspiration (ET) model (BSW) was performed to systematically evaluate and compare the effects of BFM, PFM, and no film mulching (NFM) on ET dynamics. The experiments were done in the Hetao Irrigation District of China at the Baleng experimental station (B station) with sandy soil in 2016-2017 and the Jiuzhuang experimental station (J station) with sandy loam soil in 2018-2019. The results of multi-year verification illustrated that the model accuracy was well-supported during 2016-2019 with mean absolute error (MAE) of 9.0%-16.9% and 13.1%-19.1% for ET and evaporation (E), respectively. The average cumulative ET (CET) under FM (i.e., BFM and PFM) was 443.5 mm each year and decreased by 13.4% compared to NFM. However, there was an obvious difference in CET during the different hydrological years, especially in the early crop growth stages. In the wet years (2016 and 2018), the average CET under FM increased by 6.2%-7.0% compared to NFM but decreased by 7.1%-11.8% in the dry years (2017 and 2019). The transpiration (T) difference between FM and NFM primarily appeared in the early crop growth stages, and T / ET under FM was significantly higher than with NFM by 46.9%-50.2%. An obvious E difference between BFM and PFM was observed in the later crop growing stages due to a greater area of the disintegrated biodegradable film. Additionally, crop yield under PFM and BFM increased by 35.4% and 28.3% compared with NFM, respectively, and water use efficiency (WUE) increased by 47.1% and 35.8%, respectively. Thus, biodegradable film is recommended to replace plastic film to effectively promote the development of sustainable agriculture. [ABSTRACT FROM AUTHOR] Copyright of Agricultural & Forest Meteorology is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

New Structural Economic Analysis of Anti-COVID-19 Pandemic Model of BEST Region.

The successful anti-COVID-19 pandemic model of BEST region (Beijing-Seoul-Tokyo) includes China, Japan and South Korea, which benefit from its well-functioning organizational ecosystem and specific anti-COVID-19 pandemic strategies. Under the premise of an efficient market, the capable organizations of China, Japan and South Korea will play the dynamic function of coordination and organic connection. They will also help improve the governance efficiency of facilitating state in different stages of fighting against the pandemic. This article follows the analytical logic of the new structural economics, taking the factor endowment and its structure as the starting point for the analysis, through the comparative advantage operation mode determined by the market, and based on the collaborative anti-COVID-19 pandemic perspective of the government, the market and various social organizations, to build a framework for the facilitating state-efficient market-capable organization. The key to the success of the anti-COVID-19 pandemic method in China, Japan and South Korea is organically coordinated between government, market and organizations. Based on the effective promotion of micro-organizations, governments organize resource integration and implement macro-control of the market. A dynamic balance between economic governance and pandemic prevention and control has been achieved by optimizing the endowment structure of resources, improving infrastructure and reducing system costs.

Clinical characteristics and follow-up analysis of 324 discharged COVID-19 patients in Shenzhen during the recovery period.

Objectives: Research on recovering COVID-19 patients could be helpful for containing the pandemic and developing vaccines, but we still do not know much about the clinical features, recovery process, and antibody reactions during the recovery period. Methods: We retrospectively analysed the epidemiological information, discharge summaries, and laboratory results of 324 patients. Results: In all, 15 (8.62%) patients experienced chest distress/breath shortness, where 8 of the 15 were severely ill. This means severely ill patients need an extended amount of time to recover after discharge; next, 20 (11.49%) patients experienced anxiety and 21 (12.07%) had headache/insomnia and a small fraction of them complained of anosmia/ageusia, indicating that these patients need treatment for mental and psychological health issues. Regarding the re-positive patients, their CT and laboratory test results showed no obvious evidence of illness progress or infectivity but a high anti-SARS-CoV-2 antibody expression. Conclusion: Recovered COVID-19 patients need psychological and physiological care and treatment, re-positivity can occur in any person, but juveniles, females, and patients with mild/moderate existing symptoms have higher rates of re-positivity, While there is no evidence that turning re-positive has an impact on their infectivity, but it still alerted us that we need differentiate them in the following managements.