Parthenolide reveals an allosteric mode to inhibit the deISGylation activity of SARS-CoV­2 papain-like protease.

The coronavirus papain-like protease (PLpro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for viral polypeptide cleavage and the deISGylation of interferon-stimulated gene 15 (ISG15), which enable it to participate in virus replication and host innate immune pathways. Therefore, PLpro is considered an attractive antiviral drug target. Here, we show that parthenolide, a germacrane sesquiterpene lactone, has SARS-CoV-2 PLpro inhibitory activity. Parthenolide covalently binds to Cys-191 or Cys-194 of the PLpro protein, but not the Cys-111 at the PLpro catalytic site. Mutation of Cys-191 or Cys-194 reduces the activity of PLpro. Molecular docking studies show that parthenolide may also form hydrogen bonds with Lys-192, Thr-193, and Gln-231. Furthermore, parthenolide inhibits the deISGylation but not the deubiquitinating activity of PLpro in vitro. These results reveal that parthenolide inhibits PLpro activity by allosteric regulation.

Comparison of clinical characteristics between SARS-CoV-2 Omicron variant and Delta variant infections in China

Background The continued ‘evolution’ of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the emergence of the Omicron variant after the Delta variant, resulting in a significant increase in the number of people with COVID-19. This increase in the number of cases continues to have a significant impact on lives. Therefore, a more detailed understanding of the clinical characteristics of Omicron infection is essential. Methods Using medical charts, we extracted clinical information for 384 patients infected with the Omicron variant in Anyang City, Henan Province, China. Epidemiology and clinical characteristics were compared with a cohort of people infected with the Delta variant in Zhengzhou in 2021. Findings Common initial symptoms at onset of illness were cough [240 (63%)], expectoration [112 (29%)], fever [96 (25%)], nasal congestion [96 (25%)] and myalgia or fatigue [30 (6%)]. In patients with the Omicron variant, levels of total cholesterol, low-density lipoprotein and creatinine increased in 52 (14%), 36 (9%) and 58 (15%) patients, respectively, compared with patients with the Delta variant [one (1%), one (1%) and two (2%)]. Levels of triglyceride and high-density lipoprotein also increased. In patients with the Omicron variant, the levels of specific gravity and the erythrocyte sedimentation rate were increased in 115 (30%) and 81 (21%) patients, and serum levels of complement 3 decreased in 93 (41%). Results Compared with patients infected with Delta, no major differences in initial clinical symptoms were identified in patients infected with Omicron. However, dyslipidemia and kidney injury were much more severe in patients with the Omicron variant, and the erythrocyte sedimentation rate was increased. Due to decreased levels of complement 3, the immunity of patients with the Omicron variant was weak.

Cover Image, Volume 93, Number 12, December 2021

Front Cover Caption: The cover image is based on the Research Article Updated SARS-CoV-2 single nucleotide variants and mortality association by Shuyi Fang et al., https://doi.org/10.1002/jmv.27191.

Immunogenicity and Safety of a SARS-CoV-2 Inactivated Vaccine (KCONVAC) in Healthy Adults: Two Randomized, Double-blind, and Placebo-controlled Phase 1/2 Clinical Trials (preprint)

Background The significant morbidity and mortality resulted from the infection of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) call for urgent development of effective and safe vaccines. We report the immunogenicity and safety of a SARS-CoV-2 inactivated vaccine, KCONVAC, in healthy adults. Methods Two phase 1 and phase 2 randomized, double-blind, and placebo-controlled trials of KCONVAC were conducted in Chinese healthy adults aged 18 through 59 years. The phase 1 trial was conducted in a manner of dosage escalation. The first 30 participants were randomized in a ratio of 4:1 to receive two doses of either KCONVAC at 5 g per dose or placebo on Day 0 and Day 14, and the second 30 participants were randomized to receive either KCONVAC at 10 g per dose or placebo following the same procedures. The participants in the phase 2 trial were randomized in a ratio of 2:2:1 to receive either KCONVAC at 5 g or 10 g per dose, or placebo on Day 0 and Day 14, or Day 0 and Day 28. In the phase 1 trial, the primary safety endpoint was the proportion of participants experiencing adverse reactions/events within 28 days following each vaccination. Antibody response and cellular response were assayed in the phase 1 trial. In the phase 2 trial, the primary immunogenicity endpoint was the seroconversion and titre of neutralization antibody, and the seroconversion of receptor binding domain (RBD)-IgG 28 days after the second dose. Findings In the phase 1 trial, 60 participants were enrolled and received at least one dose of 5-g vaccine (N=24), 10-g vaccine (N=24), or placebo (N=12). In the phase 2 trial, 500 participants were enrolled and received at least one dose of 5-g vaccine (N=100 for 0/14 or 0/28 regimens), 10-g vaccine (N=100 for each regimen), or placebo (N=50 for each regimen). In the phase 1 trial, 13 (54%), 11(46%), and 7 (58%) participants reported at least one adverse event (AE), of whom 10 (42%), 6 (25%), and 6 (50%) participants reported at least one vaccination-related AE after receiving 5-g vaccine, 10-g vaccine, or placebo, respectively. In the phase 2 trial, 16 (16%), 19 (19%), and 9 (18%) participants reported at least one AE, of whom 13 (13%), 17 (17%), and 6 (12%) participants reported at least one vaccination-related AE after receiving 5-g vaccine, 10-g vaccine, or placebo at the regimen of Day 0/14, respectively. Similar results were observed in the three treatment groups of Day 0/28 regimen. All the AEs were grade 1 or 2 in intensity. No AE of grade 3 or more was reported. One SAE (foot fracture) was reported in the phase 1 trial. KCONVAC induced significant antibody response. 87.5% (21/24) to 100% (24/24) of participants in the phase 1 trial and 83.0% (83/100) to 100% (99/99) of participants in the phase 2 trial seroconverted for neutralising antibody to live virus, neutralising antibody to pseudovirus, and RBD-IgG after receiving two doses. Across the treatment groups in the two trials, the geometric mean titres (GMTs) of neutralising antibody to live virus ranged from 29.3 to 49.1 at Day 0/14 regimen and from 100.2 to 131.7 at Day 0/28 regimen, neutralising antibody to pseudovirus ranged from 69.4 to 118.7 at Day 0/14 regimen and from 153.6 to 276.6 at Day 0/28 regimen, and RBD-IgG ranged from 605.3 to 1169.8 at Day 0/14 regimen and from 1496.8 to 2485.5 at Day 0/28 regimen. RBD-IgG subtyping assay showed that a significant part of RBD-IgG was IgG1. The vaccine induced obvious T-cell response with 56.5% (13/23) and 62.5% (15/24) of participants in 5-g and 10-g vaccine groups showed positive interferon-{gamma} enzyme-linked immunospot responses 14 days after the second dose in the phase 1 trial, respectively. Interpretation KCONVAC is well tolerated and able to induce robust antibody response and cellular response in adults aged 18 to 59 years, which warrants further evaluation with this vaccine in the upcoming phase 3 efficacy trial. Funding Guandong Emergency Program for Prevention and Control of COVID-19 (2020A1111340002) and Shenzhen Key Research Project for Prevention and Control of COVID-19.

Will Proton Pump Inhibitors Lead to a Higher Risk of COVID-19 Infection and Progression to Severe Disease? A Meta-analysis (preprint)

BackgroundPrevious researches on the association between proton pump inhibitors (PPIs) use and the treatment and prevention of COVID-19 have generated inconsistent findings. Therefore, this Meta-analysis was conducted to clarify the outcome in patients who take PPIs. MethodsWe carried out a systematic search to identify potential studies until November 2020. Heterogeneity was assessed using the I-squared statistic. Odds ratios (ORs) with its 95% confidence intervals (CIs) were calculated by fixed-effects or random-effects models according to the heterogeneity. Sensitivity analyses and tests for publication bias were also performed. ResultsEight articles with more than 268,683 subjects were included. PPI use was not associated with increased or decreased risk of COVID-19 infection (OR:3.16, 95%CI = 0.74-13.43, P=0.12) or mortality risk of COVID-19 patients (OR=1.91, 95% CI=0.86-4.24, P=0.11). While it can add risk of severe disease (OR=1.54, 95% CI=1.20-1.99, P<0.001;) and secondary infection (OR=4.33, 95% CI=2.57-7.29). No publication bias was detected. ConclusionsPPI use is not associated with increased risk infection and may not change the mortality risk of COVID-19, but appeared to be associated with increased risk of progression to severe disease and secondary infection. However, more original studies to further clarify the relationship between PPI and COVID-19 are still urgently needed.

Isolation and characterization of a porcine epidemic diarrhea virus strain Jiaozuo1012/2019

In order to determine the causative agent of diarrhea of suckling piglets in a pig farm in Jiaozuo city in 2019, RTPCR was used to detect the related viral pathogens from five clinical samples. The results showed that all five samples were positive for PEDV, but negative for TGEV and PoRV. A PEDV strain named as Jiaozuo1012/2019 was isolated from the positive samples by using Vero cells through detecting the fifth passaged virus by RT-PCR. The S gene and ORF3 gene of the isolated PEDV were amplified by RT-PCR, and the homology and phylogenetic tree of these two genes were analyzed by compared with PEDV reference strain in GenBank. Based on the homology analysis of S gene and ORF3 gene, S gene of this isolated PEDV had the highest homology (99.3%) with PEDV CH/HNLH/2015 strain isolated in Henan province. The homology of S gene of PEDV Jiaozuo1012/2019 strain with other strains isolated in Henan province was 96.4%-99.0%. The homology of S gene of this isolated virus with the classic PEDV CV777 strain was 93.4%, and there are 4 insertions (59QGVN62) and 3 deletions (140N and 163NI164) in S protein of this isolated virus. The ORF3 gene shared 99.7% homology with PEDV JSCZ1601 strain isolated in Jiangsu province, among 96.4%-99.0% homology with other strains isolated in Henan province, and 96.6% homology with classical PEDV CV777 strain. The phylogenetic tree analysis of S gene and ORF3 gene showed that the isolated virus had the closest genetic relationship with the current domestically epidemic strains. This study provides reference data for further studying the variation of PEDV in Henan province.