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1.
Cell Insight ; : 100029, 2022.
Article in English | ScienceDirect | ID: covidwho-1814234

ABSTRACT

The emergence of the SARS-CoV-2 Omicron variant poses a striking threat to human society. More than 30 mutations in the Spike protein of the Omicron variant severely compromised the protective immunity elicited by either vaccination or prior infection. The persistent viral evolutionary trajectory generates Omicron-associated lineages, such as BA.1 and BA.2. Moreover, the virus recombination upon Delta and Omicron co-infections has been reported lately, although the impact remains to be assessed. This minireview summarizes the characteristics, evolution and mutation control, and immune evasion mechanisms of SARS-CoV-2 variants, which will be helpful for the in-depth understanding of the SARS-CoV-2 variants and policy-making related to COVID-19 pandemic control.

2.
Signal Transduct Target Ther ; 7(1): 137, 2022 Apr 25.
Article in English | MEDLINE | ID: covidwho-1805598

ABSTRACT

Whether and how innate antiviral response is regulated by humoral metabolism remains enigmatic. We show that viral infection induces progesterone via the hypothalamic-pituitary-adrenal axis in mice. Progesterone induces downstream antiviral genes and promotes innate antiviral response in cells and mice, whereas knockout of the progesterone receptor PGR has opposite effects. Mechanistically, stimulation of PGR by progesterone activates the tyrosine kinase SRC, which phosphorylates the transcriptional factor IRF3 at Y107, leading to its activation and induction of antiviral genes. SARS-CoV-2-infected patients have increased progesterone levels, and which are co-related with decreased severity of COVID-19. Our findings reveal how progesterone modulates host innate antiviral response, and point to progesterone as a potential immunomodulatory reagent for infectious and inflammatory diseases.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Antiviral Agents , COVID-19/genetics , Humans , Hypothalamo-Hypophyseal System , Immunity, Innate/genetics , Mice , Pituitary-Adrenal System , Progesterone/pharmacology
3.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-331876

ABSTRACT

Middle East Respiratory Syndrome coronavirus (MERS-CoV) and several bat coronaviruses employ Dipeptidyl peptidase-4 (DPP4) as their functional receptors. However, the receptor for NeoCoV, the closest MERS-CoV relative yet discovered in bats, remains enigmatic. In this study, we unexpectedly found that NeoCoV and its close relative, PDF-2180-CoV, can efficiently use some types of bat Angiotensin-converting enzyme 2 (ACE2) and, less favorably, human ACE2 for entry. The two viruses use their spikes' S1 subunit carboxyl-terminal domains (S1-CTD) for high-affinity and species-specific ACE2 binding. Cryo-electron microscopy analysis revealed a novel coronavirus-ACE2 binding interface and a protein-glycan interaction, distinct from other known ACE2-using viruses. We identified a molecular determinant close to the viral binding interface that restricts human ACE2 from supporting NeoCoV infection, especially around residue Asp338. Conversely, NeoCoV efficiently infects human ACE2 expressing cells after a T510F mutation on the receptor-binding motif (RBM). Notably, the infection could not be cross-neutralized by antibodies targeting SARS-CoV-2 or MERS-CoV. Our study demonstrates the first case of ACE2 usage in MERS-related viruses, shedding light on a potential bio-safety threat of the human emergence of an ACE2 using "MERS-CoV-2" with both high fatality and transmission rate.

5.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-327593

ABSTRACT

Advanced mRNA vaccines play vital roles against SARS-CoV-2. However, due to the poor stability, most current mRNA delivery platforms need to be stored at -20 °C or -70 °C. Here we present lyophilized thermostable mRNA loaded lipid nanoparticles, which could be stored at room temperature with long-term stability. We demonstrate the applicability of lyophilization techniques to different mRNA sequences and lipid components. Three lyophilized vaccines targeting wild-type, Delta and Omicron SARS-CoV-2 variant were prepared and demonstrated to be able induce high-level of IgG titer and neutralization response. In the Delta challenge in vivo experiment, the lyophilized mRNA vaccine successfully protected the mice from infection and clear the virus. This lyophilization platform could significantly improve the accessibility of mRNA vaccine or therapeutics, particularly in remote regions.

6.
Emerg Microbes Infect ; 11(1): 567-572, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-1642256

ABSTRACT

Global concern has been raised by the emergence and rapid transmission of the heavily mutated SARS-CoV-2 Omicron variant (B.1.1.529). So far, the infection features and immune escape ability of the Omicron variant have not been extensively studied. Here, we produced the Omicron pseudovirus and compared its entry, membrane fusion, and immune escape efficiency with the original strain and the dominating Delta variant. We found the Omicron variant showed slightly higher infectivity than the Delta variant and a similar ability to compete with the Delta variant in using Angiotensin-converting enzyme 2 (ACE2) in a BHK21-ACE2 cell line. However, the Omicron showed a significantly reduced fusogenicity than the original strain and the Delta variant in both BHK21-ACE2 and Vero-E6 cells. The neutralization assay testing the Wuhan convalescents' sera one-year post-infection showed a more dramatic reduction (10.15 fold) of neutralization against the Omicron variant than the Delta variant (1.79 fold) compared with the original strain with D614G. Notably, immune-boosting through three vaccine shots significantly improved the convalescents' immunity against the Omicron variants. Our results reveal a reduced fusogenicity and a striking immune escape ability of the Omicron variant, highlighting the importance of booster shots against the challenge of the SARS-CoV-2 antigenic drift.


Subject(s)
COVID-19 , SARS-CoV-2/immunology , Animals , COVID-19/immunology , Chlorocebus aethiops , Humans , Immune Evasion , Immunization, Secondary , Vero Cells
7.
Innovation (N Y) ; 3(1): 100181, 2022 Jan 25.
Article in English | MEDLINE | ID: covidwho-1595417

ABSTRACT

Most COVID-19 convalescents can build effective anti-SARS-CoV-2 humoral immunity, but it remains unclear how long it can maintain and how efficiently it can prevent the reinfection of the emerging SARS-CoV-2 variants. Here, we tested the sera from 248 COVID-19 convalescents around 1 year post-infection in Wuhan, the earliest known epicenter. SARS-CoV-2 immunoglobulin G (IgG) was well maintained in most patients and potently neutralizes the infection of the original strain and the B.1.1.7 variant. However, varying degrees of immune escape was observed on the other tested variants in a patient-specific manner, with individuals showing remarkably broad neutralization potency. The immune escape can be largely attributed to several critical spike mutations. These results suggest that SARS-CoV-2 can elicit long-lasting immunity but this is escaped by the emerging variants.

8.
2021.
Preprint in English | Other preprints | ID: ppcovidwho-296266

ABSTRACT

5-Methylcytosine (m 5 C) is a widespread post-transcriptional RNA modification and is reported to be involved in manifold cellular responses and biological processes through regulating RNA metabolism. However, its regulatory role in antiviral innate immunity has not yet been elucidated. Here, we report that NSUN2, a typical m 5 C methyltransferase, can negatively regulate type I interferon responses during viral infection. NSUN2 specifically mediates m 5 C methylation of IRF3 mRNA and accelerates its degradation, resulting in low levels of IRF3 and downstream IFN-β production. Knockout or knockdown of NSUN2 could enhance type I interferon responses and downstream ISG expression after viral infection in vitro . And in vivo , the antiviral innate responses is more dramatically enhanced in Nsun2 +/− mice than in Nsun2 +/+ mice. Four highly m 5 C methylated cytosines in IRF3 mRNA were identified, and their mutation could enhance the cellular IRF3 mRNA levels. Moreover, infection with Sendai virus (SeV), vesicular stomatitis virus (VSV), herpes simplex virus 1 (HSV-1), Zika virus (ZIKV), or especially SARS-CoV-2 resulted in a reduction in endogenous levels of NSUN2. Together, our findings reveal that NSUN2 serves as a negative regulator of interferon response by accelerating the fast turnover of IRF3 mRNA, while endogenous NSUN2 levels decrease after viral infection to boost antiviral responses for the effective elimination of viruses. Our results suggest a paradigm of innate antiviral immune responses ingeniously involving NSUN2-mediated m 5 C modification.

10.
PLoS Pathog ; 17(9): e1009947, 2021 09.
Article in English | MEDLINE | ID: covidwho-1470670

ABSTRACT

Kaposi's sarcoma-associated herpesvirus (KSHV) preferentially infects and causes Kaposi's sarcoma (KS) in male patients. However, the biological mechanisms are largely unknown. This study was novel in confirming the extensive nuclear distribution of the androgen receptor (AR) and its co-localization with viral oncoprotein of latency-associated nuclear antigen in KS lesions, indicating a transcription way of AR in KS pathogenesis. The endogenous AR was also remarkably higher in KSHV-positive B cells than in KSHV-negative cells and responded to the ligand treatment of 5α-dihydrotestosterone (DHT), the agonist of AR. Then, the anti-AR antibody-based chromatin immunoprecipitation (ChIP)-associated sequencing was used to identify the target viral genes of AR, revealing that the AR bound to multiple regions of lytic genes in the KSHV genome. The highest peak was enriched in the core promoter sequence of polyadenylated nuclear RNA (PAN), and the physical interaction was verified by ChIP-polymerase chain reaction (PCR) and the electrophoretic mobility shift assay (EMSA). Consistently, male steroid treatment significantly transactivated the promoter activity of PAN in luciferase reporter assay, consequently leading to extensive lytic gene expression and KSHV production as determined by real-time quantitative PCR, and the deletion of nuclear localization signals of AR resulted in the loss of nuclear transport and transcriptional activity in the presence of androgen and thus impaired the expression of PAN RNA. Oncogenically, this study identified that the AR was a functional prerequisite for cell invasion, especially under the context of KSHV reactivation, through hijacking the PAN as a critical effector. Taken together, a novel mechanism from male sex steroids to viral noncoding RNA was identified, which might provide a clue to understanding the male propensity in KS.


Subject(s)
RNA, Messenger/metabolism , RNA, Viral/metabolism , Receptors, Androgen/metabolism , Sarcoma, Kaposi/metabolism , Sex Characteristics , Carcinogenesis/metabolism , Female , Herpesvirus 8, Human , Humans , Male , RNA, Untranslated/metabolism
11.
Emerg Microbes Infect ; 10(1): 1626-1637, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1348038

ABSTRACT

Coronaviruses (CoVs) can infect a variety of hosts, including humans, livestock and companion animals, and pose a serious threat to human health and the economy. The current COVID-19 pandemic, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has killed millions of people. Unfortunately, effective treatments for CoVs infection are still lacking, suggesting the importance of coronavirus vaccines. Our previous work showed that CoV nonstuctural protein 14 (nsp14) functions as (guanine-N7)-methyltransferase (N7-MTase), which is involved in RNA cap formation. Moreover, we found that N7-MTase is well conserved among different CoVs and is a universal target for developing antivirals against CoVs. Here, we show that N7-MTase of CoVs can be an ideal target for designing live attenuated vaccines. Using murine hepatitis virus strain A59 (MHV-A59), a representative and well-studied model of coronaviruses, we constructed N7-MTase-deficient recombinant MHV D330A and Y414A. These two mutants are highly attenuated in mice and exhibit similar replication efficiency to the wild-type (WT) virus in the cell culture. Furthermore, a single dose immunization of D330A or Y414A can induce long-term humoral immune responses and robust CD4+ and CD8+ T cell responses, which can provide full protection against the challenge of a lethal-dose of MHV-A59. Collectively, this study provides an ideal strategy to design live attenuated vaccines for coronavirus by abolishing viral RNA N7-MTase activity. This approach may apply to other RNA viruses that encode their own conservative viral N7-methyltransferase.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/prevention & control , SARS-CoV-2/immunology , Vaccines, Attenuated/immunology , Animals , COVID-19 Vaccines/administration & dosage , Cytokines/biosynthesis , Humans , Immunity, Cellular , Immunity, Humoral , Immunogenicity, Vaccine , Interferon Type I/biosynthesis , Male , Mice , Mutation , Vaccines, Attenuated/administration & dosage , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/immunology
12.
Cell Prolif ; 54(9): e13091, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1320384

ABSTRACT

OBJECTIVES: Recent studies have shown the presence of SARS-CoV-2 in the tissues of clinically recovered patients and persistent immune symptoms in discharged patients for up to several months. Pregnant patients were shown to be a high-risk group for COVID-19. Based on these findings, we assessed SARS-CoV-2 nucleic acid and protein retention in the placentas of pregnant women who had fully recovered from COVID-19 and cytokine fluctuations in maternal and foetal tissues. MATERIALS AND METHODS: Remnant SARS-CoV-2 in the term placenta was detected using nucleic acid amplification and immunohistochemical staining of the SARS-CoV-2 protein. The infiltration of CD14+ macrophages into the placental villi was detected by immunostaining. The cytokines in the placenta, maternal plasma, neonatal umbilical cord, cord blood and amniotic fluid specimens at delivery were profiled using the Luminex assay. RESULTS: Residual SARS-CoV-2 nucleic acid and protein were detected in the term placentas of recovered pregnant women. The infiltration of CD14+ macrophages into the placental villi of the recovered pregnant women was higher than that in the controls. Furthermore, the cytokine levels in the placenta, maternal plasma, neonatal umbilical cord, cord blood and amniotic fluid specimens fluctuated significantly. CONCLUSIONS: Our study showed that SARS-CoV-2 nucleic acid (in one patient) and protein (in five patients) were present in the placentas of clinically recovered pregnant patients for more than 3 months after diagnosis. The immune responses induced by the virus may lead to prolonged and persistent symptoms in the maternal plasma, placenta, umbilical cord, cord blood and amniotic fluid.


Subject(s)
Cytokines/analysis , Placenta/virology , RNA, Viral/isolation & purification , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Viral Proteins/isolation & purification , Adult , Amniotic Fluid/chemistry , COVID-19/pathology , Female , Fetal Blood/chemistry , Humans , Infant, Newborn , Macrophages/immunology , Nucleic Acid Amplification Techniques , Placenta/immunology , Pregnancy , RNA, Viral/blood , RNA, Viral/genetics , SARS-CoV-2/isolation & purification , Viral Proteins/blood
13.
Mol Cell ; 81(10): 2135-2147.e5, 2021 05 20.
Article in English | MEDLINE | ID: covidwho-1117323

ABSTRACT

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is currently a global pandemic. CoVs are known to generate negative subgenomes (subgenomic RNAs [sgRNAs]) through transcription-regulating sequence (TRS)-dependent template switching, but the global dynamic landscapes of coronaviral subgenomes and regulatory rules remain unclear. Here, using next-generation sequencing (NGS) short-read and Nanopore long-read poly(A) RNA sequencing in two cell types at multiple time points after infection with SARS-CoV-2, we identified hundreds of template switches and constructed the dynamic landscapes of SARS-CoV-2 subgenomes. Interestingly, template switching could occur in a bidirectional manner, with diverse SARS-CoV-2 subgenomes generated from successive template-switching events. The majority of template switches result from RNA-RNA interactions, including seed and compensatory modes, with terminal pairing status as a key determinant. Two TRS-independent template switch modes are also responsible for subgenome biogenesis. Our findings reveal the subgenome landscape of SARS-CoV-2 and its regulatory features, providing a molecular basis for understanding subgenome biogenesis and developing novel anti-viral strategies.


Subject(s)
COVID-19 , Genome, Viral , High-Throughput Nucleotide Sequencing , RNA, Viral , SARS-CoV-2 , Animals , COVID-19/genetics , COVID-19/metabolism , Caco-2 Cells , Chlorocebus aethiops , Humans , RNA, Viral/genetics , RNA, Viral/metabolism , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Vero Cells
14.
Nat Ecol Evol ; 5(5): 600-608, 2021 05.
Article in English | MEDLINE | ID: covidwho-1111986

ABSTRACT

Bats are the suggested natural hosts for severe acute respiratory syndrome coronavirus (SARS-CoV) and the causal agent of the coronavirus disease 2019 (COVID-19) pandemic, SARS-CoV-2. The interaction of viral spike proteins with their host receptor angiotensin-converting enzyme 2 (ACE2) is a critical determinant of potential hosts and cross-species transmission. Here we use virus-host receptor binding and infection assays to examine 46 ACE2 orthologues from phylogenetically diverse bat species, including those in close and distant contact with humans. We found that 24, 21 and 16 of them failed to support infection by SARS-CoV, SARS-CoV-2 or both viruses, respectively. Furthermore, we confirmed that infection assays in human cells were consistent with those in two bat cell lines. Additionally, we used genetic and functional analyses to identify critical residues in bat ACE2 receptors associated with viral entry restrictions. Our results suggest that many bat species may not be the potential hosts of one or both viruses and that no correlation was identified between proximity to humans and probability of being natural hosts of SARS-CoV or SARS-CoV-2. This study demonstrates dramatic variation in susceptibility to SARS-CoV and SARS-CoV-2 infection among bat species and adds knowledge towards a better understanding of coronavirus-bat interaction.


Subject(s)
COVID-19 , Chiroptera , Angiotensin-Converting Enzyme 2 , Animals , Humans , Peptidyl-Dipeptidase A/genetics , Receptors, Virus/genetics , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/genetics
15.
Cell Res ; 31(4): 395-403, 2021 04.
Article in English | MEDLINE | ID: covidwho-1091494

ABSTRACT

The upcoming flu season in the Northern Hemisphere merging with the current COVID-19 pandemic raises a potentially severe threat to public health. Through experimental coinfection with influenza A virus (IAV) and either pseudotyped or live SARS-CoV-2 virus, we found that IAV preinfection significantly promoted the infectivity of SARS-CoV-2 in a broad range of cell types. Remarkably, in vivo, increased SARS-CoV-2 viral load and more severe lung damage were observed in mice coinfected with IAV. Moreover, such enhancement of SARS-CoV-2 infectivity was not observed with several other respiratory viruses, likely due to a unique feature of IAV to elevate ACE2 expression. This study illustrates that IAV has a unique ability to aggravate SARS-CoV-2 infection, and thus, prevention of IAV infection is of great significance during the COVID-19 pandemic.


Subject(s)
COVID-19/pathology , Coinfection/pathology , Influenza A virus/physiology , Orthomyxoviridae Infections/pathology , SARS-CoV-2/physiology , Angiotensin-Converting Enzyme 2/deficiency , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/virology , Cathepsin L/genetics , Cathepsin L/metabolism , Cell Line , Coinfection/virology , Humans , Influenza A virus/isolation & purification , Lung/pathology , Mice , Mice, Transgenic , Orthomyxoviridae Infections/virology , RNA, Guide/metabolism , SARS-CoV-2/isolation & purification , Serine Endopeptidases/genetics , Serine Endopeptidases/metabolism , Severity of Illness Index , Viral Load , Virus Internalization
16.
Protein Cell ; 2020 Nov 09.
Article in English | MEDLINE | ID: covidwho-915250

ABSTRACT

In the original publication the author's name 'Dimitri Lavillete' is published incorrectly. The correct author name should be spelt as 'Dimitri Lavillette' is provided in this correction.

18.
SSRN; 2020.
Preprint | SSRN | ID: ppcovidwho-587

ABSTRACT

Circulating in China and 75 other countries and territories, the ongoing COVID-19 outbreak has caused devastating mortality and posed a great threat to public h

19.
Protein Cell ; 11(10): 723-739, 2020 10.
Article in English | MEDLINE | ID: covidwho-697126

ABSTRACT

Emerging and re-emerging RNA viruses occasionally cause epidemics and pandemics worldwide, such as the on-going outbreak of the novel coronavirus SARS-CoV-2. Herein, we identified two potent inhibitors of human DHODH, S312 and S416, with favorable drug-likeness and pharmacokinetic profiles, which all showed broad-spectrum antiviral effects against various RNA viruses, including influenza A virus, Zika virus, Ebola virus, and particularly against SARS-CoV-2. Notably, S416 is reported to be the most potent inhibitor so far with an EC50 of 17 nmol/L and an SI value of 10,505.88 in infected cells. Our results are the first to validate that DHODH is an attractive host target through high antiviral efficacy in vivo and low virus replication in DHODH knock-out cells. This work demonstrates that both S312/S416 and old drugs (Leflunomide/Teriflunomide) with dual actions of antiviral and immuno-regulation may have clinical potentials to cure SARS-CoV-2 or other RNA viruses circulating worldwide, no matter such viruses are mutated or not.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus Infections/drug therapy , Oxidoreductases/antagonists & inhibitors , Pandemics , Pneumonia, Viral/drug therapy , RNA Viruses/drug effects , Thiazoles/pharmacology , Animals , Antiviral Agents/therapeutic use , Betacoronavirus/drug effects , Betacoronavirus/physiology , Binding Sites/drug effects , COVID-19 , Cell Line , Coronavirus Infections/virology , Crotonates/pharmacology , Cytokine Release Syndrome/drug therapy , Drug Evaluation, Preclinical , Gene Knockout Techniques , Humans , Hydroxybutyrates , Influenza A virus/drug effects , Leflunomide/pharmacology , Mice , Mice, Inbred BALB C , Nitriles , Orthomyxoviridae Infections/drug therapy , Oseltamivir/therapeutic use , Oxidoreductases/metabolism , Oxidoreductases Acting on CH-CH Group Donors , Pneumonia, Viral/virology , Protein Binding/drug effects , Pyrimidines/biosynthesis , RNA Viruses/physiology , SARS-CoV-2 , Structure-Activity Relationship , Thiazoles/therapeutic use , Toluidines/pharmacology , Ubiquinone/metabolism , Virus Replication/drug effects
20.
Virol Sin ; 35(6): 725-733, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-659402

ABSTRACT

We recently reported that inhibitors against human dihydroorotate dehydrogenase (DHODH) have broad-spectrum antiviral activities including their inhibitory efficacies on SARS-CoV-2 replication in infected cells. However, there are limited data from clinical studies to prove the application of DHODH inhibitors in Coronavirus disease 2019 (COVID-19) patients. In the present study, we evaluated Leflunomide, an approved DHODH inhibitor widely used as a modest immune regulator to treat autoimmune diseases, in treating COVID-19 disease with a small-scale of patients. Cases of 10 laboratory-confirmed COVID-19 patients of moderate type with obvious opacity in the lung were included. Five of the patients were treated with Leflunomide, and another five were treated as blank controls without a placebo. All the patients accepted standard supportive treatment for COVID-19. The patients given Leflunomide had a shorter viral shedding time (median of 5 days) than the controls (median of 11 days, P = 0.046). The patients given Leflunomide also showed a significant reduction in C-reactive protein levels, indicating that immunopathological inflammation was well controlled. No obvious adverse effects were observed in Leflunomide-treated patients, and they all discharged from the hospital faster than controls. This preliminary study on a small-scale compassionate use of Leflunomide provides clues for further understanding of Leflunomide as a potential antiviral drug against COVID-19.


Subject(s)
Antiviral Agents/administration & dosage , COVID-19/drug therapy , Leflunomide/administration & dosage , Aged , C-Reactive Protein/metabolism , COVID-19/diagnostic imaging , COVID-19/metabolism , COVID-19/virology , China , Female , Humans , Lung/diagnostic imaging , Lung/drug effects , Male , Middle Aged , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Virus Replication/drug effects , Virus Shedding/drug effects
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