A new generation Mpro inhibitor with potent activity against SARS-CoV-2 Omicron variants.

Emerging SARS-CoV-2 variants, particularly the Omicron variant and its sublineages, continually threaten the global public health. Small molecule antivirals are an effective treatment strategy to fight against the virus. However, the first-generation antivirals either show limited clinical efficacy and/or have some defects in pharmacokinetic (PK) properties. Moreover, with increased use of these drugs across the globe, they face great pressure of drug resistance. We herein present the discovery and characterization of a new generation antiviral drug candidate (SY110), which is a potent and selective inhibitor of SARS-CoV-2 main protease (Mpro). This compound displayed potent in vitro antiviral activity against not only the predominant SARS-CoV-2 Omicron sublineage BA.5, but also other highly pathogenic human coronaviruses including SARS-CoV-1 and MERS-CoV. In the Omicron-infected K18-hACE2 mouse model, oral treatment with SY110 significantly lowered the viral burdens in lung and alleviated the virus-induced pathology. Importantly, SY110 possesses favorable PK properties with high oral drug exposure and oral bioavailability, and also an outstanding safety profile. Furthermore, SY110 exhibited sensitivity to several drug-resistance Mpro mutations. Collectively, this investigation provides a promising new drug candidate against Omicron and other variants of SARS-CoV-2.

Discovery of 3-phenyl-1,2,4-oxadiazole derivatives as a new class of SARS-CoV-2 main protease inhibitors.

The ongoing COVID-19 pandemic has led to massive infections and deaths and caused tremendous grief among the people. Although vaccines have played an important role in fighting COVID-19, the situation that the protective effect of current vaccines significantly decreases against mutated strains reminds us of the pressing need for developing effective antiviral therapeutics. The main protease (Mpro) is a key enzyme for SARS-CoV-2 viral replication and transcription and an attractive target for drug development. In this research, we report a new series of Mpro inhibitors containing 3-phenyl-1,2,4-oxadiazole. Structure-activity relationship (SAR) studies led to the discovery of the most active compound, 16d, which showed an IC50 value of 5.27 ± 0.26 µM. Collectively, we obtained a new small molecular inhibitor targeting SARS-CoV-2 Mpro, which contains a new scaffold. This compound could be taken as a lead compound for subsequent drug discovery against SARS-CoV-2.

Death Receptor DR5 as a Proviral Factor for Viral Entry and Replication of Coronavirus PEDV.

Porcine epidemic diarrhea virus (PEDV), a member of Coronaviridae, causes high mortality in newborn piglets, and has caused significant economic losses in the pig industry. PEDV infection can induce apoptosis, both caspase-dependent and caspase-independent, but the details of apoptosis remain clarified. This study investigated the effect of death receptor DR5 on PEDV infection and its relationship with PEDV-induced apoptosis. We found that DR5 knockdown reduced viral mRNA and protein levels of PEDV, and the viral titer decreased from 104.5 TCID50 to 103.4 TCID50 at 12 hpi. Overexpression of DR5 significantly increased the viral titer. Further studies showed that DR5 facilitates viral replication by regulating caspase-8-dependent apoptosis, and the knockdown of DR5 significantly reduced PEDV-induced apoptosis. Interestingly, we detected a biphasic upregulation expression of DR5 in both Vero cells and piglets in response to PEDV infection. We found that DR5 also facilitates viral entry of PEDV, especially, incubation with DR5 antibody can reduce the PEDV binding to Vero cells. Our study improves the understanding of the mechanism by which PEDV induces apoptosis and provides new insights into the biological function of DR5 in PEDV infection.

Anti-social behaviour and economic decision-making: Panel experimental evidence in the wake of COVID-19.

We systematically examine the acute impact of exposure to a public health crisis on anti-social behaviour and economic decision-making using unique experimental panel data from China, collected just before the outbreak of COVID-19 and immediately after the first wave was overcome. Exploiting plausibly exogenous geographical variation in virus exposure coupled with a dataset of longitudinal experiments, we show that participants who were more intensely exposed to the virus outbreak became more anti-social than those with lower exposure, while other aspects of economic and social preferences remain largely stable. The finding is robust to multiple hypothesis testing and a similar, yet less pronounced pattern emerges when using alternative measures of virus exposure, reflecting societal concern and sentiment, constructed using social media data. The anti-social response is particularly pronounced for individuals who experienced an increase in depression or negative affect, which highlights the important role of psychological health as a potential mechanism through which the virus outbreak affected behaviour.

Data Mining on COVID-19 Vaccines: Side Effects.

COVID-19 is a pandemic disease affecting billions of people worldwide. Taking vaccines is a most effective approach to gain fully control. Thanks to the coordinated efforts from all over the world, several brands of vaccines targeting COVID-19 have passed through clinical trials and been brought to the public. Growing numbers of people are taking vaccines and share their feedback on social media, mostly on Twitter. In this study, we used Twitter data to analyze the side effects on each individual and quantify these side effects in a brand-wise and country-wise manner. Based on Twitter data, we found that the United States has the largest number of people getting vaccinated, Pfizer is the most widely used vaccine brand around the world and the most frequent side effect is cold. From our analysis, the side effects of vaccines are under controllable and are acceptable, and everyone can join the vaccinated camping without hesitation.

SARS-CoV-2 Mpro inhibitors with antiviral activity in a transgenic mouse model.

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continually poses serious threats to global public health. The main protease (Mpro) of SARS-CoV-2 plays a central role in viral replication. We designed and synthesized 32 new bicycloproline-containing Mpro inhibitors derived from either boceprevir or telaprevir, both of which are approved antivirals. All compounds inhibited SARS-CoV-2 Mpro activity in vitro, with 50% inhibitory concentration values ranging from 7.6 to 748.5 nM. The cocrystal structure of Mpro in complex with MI-23, one of the most potent compounds, revealed its interaction mode. Two compounds (MI-09 and MI-30) showed excellent antiviral activity in cell-based assays. In a transgenic mouse model of SARS-CoV-2 infection, oral or intraperitoneal treatment with MI-09 or MI-30 significantly reduced lung viral loads and lung lesions. Both also displayed good pharmacokinetic properties and safety in rats.

Toxicology Advances for 21st Century Chemical Pollution.

Pollution represents a leading threat to global health and ecosystems. Systems-based initiatives, including Planetary Health, EcoHealth, and One Health, require theoretical and translational platforms to address chemical pollution. Comparative and predictive toxicology are providing integrative approaches for identifying problematic contaminants, designing less hazardous alternatives, and reducing the impacts of chemical pollution.

[Clinical features of asymptomatic or subclinical COVID-19 in children]

OBJECTIVE: To study the clinical features of asymptomatic or subclinical coronavirus disease 2019 (COVID-19) in children. METHODS: A retrospective analysis was performed for the clinical data of 53 children who were confirmed with asymptomatic or subclinical COVID-19, including epidemiological history, clinical typing, co-infection, time to clearance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid in nasopharyngeal swabs, laboratory examination results, length of hospital stay, and treatment outcome. RESULTS: The children with asymptomatic or subclinical COVID-19 accounted for 30.5% (53/174) in children with COVID-19 hospitalized in the COVID-19 ward of Wuhan Children's Hospital. All cases occurred with familial aggregation. Among the 53 children, 35 (66%) had asymptomatic infection and 18 (34%) had subclinical infection. Mycoplasma infection was found in 17 children (32%). For the 53 children, the mean time to clearance of SARS-CoV-2 nucleic acid in nasopharyngeal swabs was 9+/-4 days. Most laboratory markers were maintained within the normal range. The mean hospital stay was 11+/-4 days. Lung CT of 18 children with subclinical COVID-19 showed ground-glass opacities, linear opacities, and patchy opacities, with relatively limited lesions. CONCLUSIONS: There is a high proportion of children with asymptomatic or subclinical COVID-19 among the children with COVID-19 hospitalized in the COVID-19 ward. The transmission risk of asymptomatic or subclinical COVID-19 should be taken seriously.