Understanding interactions between the host and SARS-CoV-2 is essential for developing effective vaccines and therapeutics.Here,we report that SARS-CoV-2 usurps the host ubiquitin system to polyubiquitinate accessory ...Understanding interactions between the host and SARS-CoV-2 is essential for developing effective vaccines and therapeutics.Here,we report that SARS-CoV-2 usurps the host ubiquitin system to polyubiquitinate accessory protein ORF7a at Lys119.The 0RF7a polyubiquitination is primarily formed by K63-linked ubiquitin chains.展开更多
Many flaviviruses are emerging and reemerging pathogens, such as West Nile virus （WNV）, dengue virus （DENV）, yellow fever virus （YFV）, and Japanese encephalitis virus. Serological assay is the dominant method fo...Many flaviviruses are emerging and reemerging pathogens, such as West Nile virus （WNV）, dengue virus （DENV）, yellow fever virus （YFV）, and Japanese encephalitis virus. Serological assay is the dominant method for diagnosis of flavivirus infections in human. Because antibodies generated during flavivirus infections cross-react with other flavivirus members, plaque reduction neutralization test （PRNT） is the only available assay to determine the infecting flavivirus type. Since PRNT requires culturing raw viruses, it must be performed in biosafety levet-3 or level-4 containment for many flaviviruses, and takes more than ten days to complete. To overcome these problems, we have developed flavivirus viral-like particles （VLPs） that could be used to replace raw viruses in the neutralization assay. The VLPs were prepared by trans packaging a luciferase-reporting replicon with viral structural proteins. This novel assay involves three simple steps： （i） VLPs from a panel of flaviviruses are incubated with flavivirus-infected sera at 37℃ for 1 h; （ii）the neutralized VLPs are used to infect Vero cells; and （iii） the infected cells are measured for luciferase activities at 22 h post-infection. The virus type whose VLP is most efficiently neutralized by the serum specimen （as quantified by the luciferase activities） is the etiologic agent. As a proof-of-concept, we show that a WNV-infected mouse serum neutralized the WNV VLP more efficiently and selectively than the DENV and YFV VLPs. Our results demonstrate that the VLP neutralization assay maintains the ＂gold standard＂ of the classic PRNT; importantly, it shortens the assay time from 〉10 days to 〈1 day, and can be performed in biosafety level-2 facility.展开更多
Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron (B.1.1.529) variant is highly transmissible with potential immune escape. Hence, control measures are continuously being optimized to gu...Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron (B.1.1.529) variant is highly transmissible with potential immune escape. Hence, control measures are continuously being optimized to guard against large-scale coronavirus disease 2019 (COVID-19) outbreaks. This study aimed to explore the relationship between the intensity of control measures in response to different SARS-CoV-2 variants and the degree of outbreak control at city level.Methods: A retrospective study was conducted in 49 cities with COVID-19 outbreaks between January 2020 and June 2022. Epidemiological data on COVID-19 were extracted from the National Health Commission, People’s Republic of China, and the population flow data were sourced from the Baidu migration data provided by the Baidu platform. Outbreak control was quantified by calculating the degree of infection growth and the time-varying reproduction number (Rt). The intensity of the outbreak response was quantified by calculating the reduction in population mobility during the outbreak period. Correlation and regression analyses of the intensity of the control measures and the degree of outbreak control for the Omicron variant and non-Omicron mutants were conducted, respectively.Results: Overall, 65 outbreaks occurred in 49 cities in China from January 2020 to June 2022. Of them, 66.2% were Omicron outbreaks and 33.8% were non-Omicron outbreaks. The intensity of the control measures was positively correlated with the degree of outbreak control (r = 0.351,P = 0.03). The degree of reduction in population mobility was negatively correlated with the R_(t) value (r = - 0.612,P < 0.01). Therefore, under the same control measure intensity, the number of new daily Omicron infections was 6.04 times higher than those attributed to non-Omicron variants, and theRt value of Omicron outbreaks was 2.6 times higher than that of non-Omicron variants. In addition, the duration of non-Omicron variant outbreaks was shorter than that of the outbreaks caused by the Omicron varian展开更多
The severe acute respiratory syndrome coronavirus 2(SARS-CovV-2)infection is associated with a hyperinflammatory state and lymphocytopenia,a hallmark that appears as both signature and prognosis of disease severity ou...The severe acute respiratory syndrome coronavirus 2(SARS-CovV-2)infection is associated with a hyperinflammatory state and lymphocytopenia,a hallmark that appears as both signature and prognosis of disease severity outcome.Although cytokine storm and a sustained inflammatory state are commonly associated with immune cell depletion,it is still unclear whether direct SARS-Cov-2 infection of immune cells could also play a role in this scenario by harboring viral replication.We found that monocytes,as well as both B and T lymphocytes,were susceptible to SARS-Cov-2 infection in vitro,accumulating double-stranded RNA consistent with viral RNA replication and ultimately leading to expressive T cell apoptosis.In addition,flow cytometry and immunofluorescence analysis revealed that SARS-Cov-2 was frequently detected in monocytes and B lymphocytes from coronavirus disease 2019(CoVID-19)patients.The rates of SARS-Cov-2-infected monocytes in peripheral blood mononuclear cells from CoVID-19 patients increased over time from symptom onset,with SARS-CoV-2-positive monocytes,B cells,and CD4+T lymphocytes also detected in postmortem lung tissue.These results indicated that SARS-CoV-2 infection of blood-circulating leukocytes in covID-19 patients might have important implications for disease pathogenesis and progression,immune dysfunction,and virus spread within the host.展开更多
Emerging viral diseases pose global threat to public health. It is essential to build capacity to response and counteract against emerging viral diseases. Towards achieving this important goal of public health, the St...Emerging viral diseases pose global threat to public health. It is essential to build capacity to response and counteract against emerging viral diseases. Towards achieving this important goal of public health, the State Key Laboratory of Virology of China has organized the International Symposium on Emerging Viral展开更多
In the winter of 2015,the first dengue vaccine(Dengvaxia)was approved for clinical use.Dengue virus is the most prevalent mosquito-transmitted viral pathogen in humans(Qin and Shi,2014).Even though the approved Dengva...In the winter of 2015,the first dengue vaccine(Dengvaxia)was approved for clinical use.Dengue virus is the most prevalent mosquito-transmitted viral pathogen in humans(Qin and Shi,2014).Even though the approved Dengvaxia has its weaknesses(e.g.,low protection against serotype-2virus),it has been recently licensed to Mexico,Philippines,展开更多
Dear Editor The rapid evolution of SARS-CoV-2 mandates a better under-standing of cross-neutralization and cross-protection among variants.Such information is essential to guide vaccine strategy and public policy.To e...Dear Editor The rapid evolution of SARS-CoV-2 mandates a better under-standing of cross-neutralization and cross-protection among variants.Such information is essential to guide vaccine strategy and public policy.To examine the cross-protection among different variant spikes,we initially prepared four chimeric SARS-CoV-2 viruses(Fig.1a),each bearing the spike gene from Alpha,Beta,Gamma,or Epsilon in the backbone of USA-WA1/2020[isolated in January 2020 and defned as wild-type(WT)].展开更多
Many flaviviruses are significant human pathogens.The plus-strand RNA genome of a flavivirus contains a 5′terminal cap 1 structure(m7GpppAmG).The flavivirus encodes one methyltransferase(MTase),located at the Ntermin...Many flaviviruses are significant human pathogens.The plus-strand RNA genome of a flavivirus contains a 5′terminal cap 1 structure(m7GpppAmG).The flavivirus encodes one methyltransferase(MTase),located at the Nterminal portion of the NS5 RNA-dependent RNA polymerase(RdRp).Here we review recent advances in our understanding of flaviviral capping machinery and the implications for drug development.The NS5 MTase catalyzes both guanine N7 and ribose 2'-OH methylations during viral cap formation.Representative flavivirus MTases,from dengue,yellow fever,and West Nile virus(WNV),sequentially generate GpppA!m7GpppA!m7GpppAm.Despite the existence of two distinct methylation activities,the crystal structures of flavivirus MTases showed a single binding site for S-adenosyl-L-methionine(SAM),the methyl donor.This finding indicates that the substrate GpppA-RNA must be repositioned to accept the N7 and 2'-O methyl groups from SAM during the sequential reactions.Further studies demonstrated that distinct RNA elements are required for the methylations of guanine N7 on the cap and of ribose 2'-OH on the first transcribed nucleotide.Mutant enzymes with different methylation defects can trans complement one another in vitro,demonstrating that separate molecules of the enzyme can independently catalyze the two cap methylations in vitro.In the context of the infectious virus,defects in both methylations,or a defect in the N7 methylation alone,are lethal to WNV.However,viruses defective solely in 2'-O methylation are attenuated and can protect mice from later wild-typeWNV challenge.The results demonstrate that the N7 methylation activity is essential for the WNV life cycle and,thus,methyltransferase represents a novel and promising target for flavivirus therapy.展开更多
文摘Understanding interactions between the host and SARS-CoV-2 is essential for developing effective vaccines and therapeutics.Here,we report that SARS-CoV-2 usurps the host ubiquitin system to polyubiquitinate accessory protein ORF7a at Lys119.The 0RF7a polyubiquitination is primarily formed by K63-linked ubiquitin chains.
基金supported by National Institute of Health grants U01 AI061193 and U54-AI057158 (Northeast Biodefense Center).
文摘Many flaviviruses are emerging and reemerging pathogens, such as West Nile virus （WNV）, dengue virus （DENV）, yellow fever virus （YFV）, and Japanese encephalitis virus. Serological assay is the dominant method for diagnosis of flavivirus infections in human. Because antibodies generated during flavivirus infections cross-react with other flavivirus members, plaque reduction neutralization test （PRNT） is the only available assay to determine the infecting flavivirus type. Since PRNT requires culturing raw viruses, it must be performed in biosafety levet-3 or level-4 containment for many flaviviruses, and takes more than ten days to complete. To overcome these problems, we have developed flavivirus viral-like particles （VLPs） that could be used to replace raw viruses in the neutralization assay. The VLPs were prepared by trans packaging a luciferase-reporting replicon with viral structural proteins. This novel assay involves three simple steps： （i） VLPs from a panel of flaviviruses are incubated with flavivirus-infected sera at 37℃ for 1 h; （ii）the neutralized VLPs are used to infect Vero cells; and （iii） the infected cells are measured for luciferase activities at 22 h post-infection. The virus type whose VLP is most efficiently neutralized by the serum specimen （as quantified by the luciferase activities） is the etiologic agent. As a proof-of-concept, we show that a WNV-infected mouse serum neutralized the WNV VLP more efficiently and selectively than the DENV and YFV VLPs. Our results demonstrate that the VLP neutralization assay maintains the ＂gold standard＂ of the classic PRNT; importantly, it shortens the assay time from 〉10 days to 〈1 day, and can be performed in biosafety level-2 facility.
基金the fund of the fund of Three-year Action Plan for Promoting Clinical Skills and Innovation Ability of Municipal Hospitals(Grant No.SHDC2022CRS039)Medical Innovation Research Special Project of the Shanghai“Science and Technology Innovation Action Plan”(Grant Nos.21Y11922500,21Y11922400)+2 种基金the fund of talent fund of Longhua Hospital(Grant No.LH001.007)In addition,it was also supported by scientific research project on prevention and treatment of COVID-19 with traditional Chinese medicine(Grant No.XGYJKY2022-09)the emergency study of traditional Chinese medicine on COVID-19(Grant No.2022ZYLCYJ05-10)。
文摘Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron (B.1.1.529) variant is highly transmissible with potential immune escape. Hence, control measures are continuously being optimized to guard against large-scale coronavirus disease 2019 (COVID-19) outbreaks. This study aimed to explore the relationship between the intensity of control measures in response to different SARS-CoV-2 variants and the degree of outbreak control at city level.Methods: A retrospective study was conducted in 49 cities with COVID-19 outbreaks between January 2020 and June 2022. Epidemiological data on COVID-19 were extracted from the National Health Commission, People’s Republic of China, and the population flow data were sourced from the Baidu migration data provided by the Baidu platform. Outbreak control was quantified by calculating the degree of infection growth and the time-varying reproduction number (Rt). The intensity of the outbreak response was quantified by calculating the reduction in population mobility during the outbreak period. Correlation and regression analyses of the intensity of the control measures and the degree of outbreak control for the Omicron variant and non-Omicron mutants were conducted, respectively.Results: Overall, 65 outbreaks occurred in 49 cities in China from January 2020 to June 2022. Of them, 66.2% were Omicron outbreaks and 33.8% were non-Omicron outbreaks. The intensity of the control measures was positively correlated with the degree of outbreak control (r = 0.351,P = 0.03). The degree of reduction in population mobility was negatively correlated with the R_(t) value (r = - 0.612,P < 0.01). Therefore, under the same control measure intensity, the number of new daily Omicron infections was 6.04 times higher than those attributed to non-Omicron variants, and theRt value of Omicron outbreaks was 2.6 times higher than that of non-Omicron variants. In addition, the duration of non-Omicron variant outbreaks was shorter than that of the outbreaks caused by the Omicron varian
基金supported by Conselho Nacional de Desenvolviment Coientificoe Tecnologico(CNPq310100/2017-8,403201/2020-9,and INCT 465539/2014-9)+3 种基金Fundagaode Amparoa Pesquisado Estado deSao Paulo(FAPESP2013/16349-2 and 2014/02438-6)the National Institutes of Health(NIHAl163019).M.C.P and R.G.were funded by CNPq(380849/2020-8).
文摘The severe acute respiratory syndrome coronavirus 2(SARS-CovV-2)infection is associated with a hyperinflammatory state and lymphocytopenia,a hallmark that appears as both signature and prognosis of disease severity outcome.Although cytokine storm and a sustained inflammatory state are commonly associated with immune cell depletion,it is still unclear whether direct SARS-Cov-2 infection of immune cells could also play a role in this scenario by harboring viral replication.We found that monocytes,as well as both B and T lymphocytes,were susceptible to SARS-Cov-2 infection in vitro,accumulating double-stranded RNA consistent with viral RNA replication and ultimately leading to expressive T cell apoptosis.In addition,flow cytometry and immunofluorescence analysis revealed that SARS-Cov-2 was frequently detected in monocytes and B lymphocytes from coronavirus disease 2019(CoVID-19)patients.The rates of SARS-Cov-2-infected monocytes in peripheral blood mononuclear cells from CoVID-19 patients increased over time from symptom onset,with SARS-CoV-2-positive monocytes,B cells,and CD4+T lymphocytes also detected in postmortem lung tissue.These results indicated that SARS-CoV-2 infection of blood-circulating leukocytes in covID-19 patients might have important implications for disease pathogenesis and progression,immune dysfunction,and virus spread within the host.
文摘Emerging viral diseases pose global threat to public health. It is essential to build capacity to response and counteract against emerging viral diseases. Towards achieving this important goal of public health, the State Key Laboratory of Virology of China has organized the International Symposium on Emerging Viral
基金Chengfeng Qin was supported by the Excellent Young Scientist Program of the National Natural Science Foundation (81522025)XF Li was supported by the Beijing Nova Program of Science & Technology (2016110)
文摘In the winter of 2015,the first dengue vaccine(Dengvaxia)was approved for clinical use.Dengue virus is the most prevalent mosquito-transmitted viral pathogen in humans(Qin and Shi,2014).Even though the approved Dengvaxia has its weaknesses(e.g.,low protection against serotype-2virus),it has been recently licensed to Mexico,Philippines,
文摘Dear Editor The rapid evolution of SARS-CoV-2 mandates a better under-standing of cross-neutralization and cross-protection among variants.Such information is essential to guide vaccine strategy and public policy.To examine the cross-protection among different variant spikes,we initially prepared four chimeric SARS-CoV-2 viruses(Fig.1a),each bearing the spike gene from Alpha,Beta,Gamma,or Epsilon in the backbone of USA-WA1/2020[isolated in January 2020 and defned as wild-type(WT)].
基金This research was partially supported by grants from the National Institute of Health(NIH)(No.AI07079201A1)to H.L。
文摘Many flaviviruses are significant human pathogens.The plus-strand RNA genome of a flavivirus contains a 5′terminal cap 1 structure(m7GpppAmG).The flavivirus encodes one methyltransferase(MTase),located at the Nterminal portion of the NS5 RNA-dependent RNA polymerase(RdRp).Here we review recent advances in our understanding of flaviviral capping machinery and the implications for drug development.The NS5 MTase catalyzes both guanine N7 and ribose 2'-OH methylations during viral cap formation.Representative flavivirus MTases,from dengue,yellow fever,and West Nile virus(WNV),sequentially generate GpppA!m7GpppA!m7GpppAm.Despite the existence of two distinct methylation activities,the crystal structures of flavivirus MTases showed a single binding site for S-adenosyl-L-methionine(SAM),the methyl donor.This finding indicates that the substrate GpppA-RNA must be repositioned to accept the N7 and 2'-O methyl groups from SAM during the sequential reactions.Further studies demonstrated that distinct RNA elements are required for the methylations of guanine N7 on the cap and of ribose 2'-OH on the first transcribed nucleotide.Mutant enzymes with different methylation defects can trans complement one another in vitro,demonstrating that separate molecules of the enzyme can independently catalyze the two cap methylations in vitro.In the context of the infectious virus,defects in both methylations,or a defect in the N7 methylation alone,are lethal to WNV.However,viruses defective solely in 2'-O methylation are attenuated and can protect mice from later wild-typeWNV challenge.The results demonstrate that the N7 methylation activity is essential for the WNV life cycle and,thus,methyltransferase represents a novel and promising target for flavivirus therapy.
