The outbreak of coronavirus disease 2019(COVID-19)caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is a serious global health threat.This raises an urgent need for the development of effective drug...The outbreak of coronavirus disease 2019(COVID-19)caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is a serious global health threat.This raises an urgent need for the development of effective drugs against the deadly disease.SARS-CoV-2 non-structural protein 14(NSP14)carrying RNA cap guanine N7-methyltransferase and 30-50 exoribonuclease activities could be a potential drug target for intervention.NSP14 of SARS-CoV-2 shares 98.7%of similarity with the one(PDB 5NFY)of acute respiratory syndrome(SARS)by ClustalW.Then,the SARS-CoV-2 NSP14 structures were modelled by Modeller 9.18 using SARS NSP14(PDB 5NFY)as template for virtual screening.Based on the docking score from AutoDock Vina1.1.2,18 small molecule drugs were selected for further evaluation.Based on the 5 ns MD simulation trajectory,binding free energy(DG)was calculated by MM/GBSA method.The calculated binding free energies of Saquinavir,Hypericin,Baicalein and Bromocriptine for the N-terminus of the homology model wereà37.2711±3.2160,à30.1746±3.1914,à23.8953±4.4800,andà34.1350±4.3683 kcal/mol,respectively,while the calculated binding free energies wereà60.2757±4.7708,à30.9955±2.9975,à46.3099±3.5689,andà59.8104±3.5389 kcal/mol,respectively,when binding to the C-terminus.Thus,the compounds including Saquinavir,Hypericin,Baicalein and Bromocriptine could bind to the N-terminus and C-terminus of the homology model of the SARS-CoV-2 NSP14,providing a candidate drug against SARS-CoV-2 for further study.展开更多
Coronaviruses(CoVs)are a group of related enveloped RNA viruses that have severe consequences in a wide variety of animals by causing respiratory,enteric or systemic diseases.Porcine epidemic diarrhea virus(PEDV)is an...Coronaviruses(CoVs)are a group of related enveloped RNA viruses that have severe consequences in a wide variety of animals by causing respiratory,enteric or systemic diseases.Porcine epidemic diarrhea virus(PEDV)is an economically important CoV distributed worldwide that causes diarrhea in pigs.nsp14 is a nonstructural protein of PEDV that is involved in regulation of innate immunity and viral replication.However,the function and mechanism by which nsp14 modulates and manipulates host immune responses remain largely unknown.Here,we report that PEDV nsp14 is an NF-κB pathway antagonist.Overexpression PEDV nsp14 protein remarkably decreases SeV-,poly(I:C)-and TNF-α-induced NF-κB activation.Meanwhile,expression of proinflammatory cytokines is suppressed by nspl4.nsp14 inhibits the phosphorylation of IKKs by interacting with IKKs and p65.Furthermore,nsp14 suppresses TNF-α-induced phosphorylation and nuclear import of p65.Overexpression nsp14 considerably increases PEDV replication.These results suggest a novel mechanism employed by PEDV to suppress the host antiviral response,providing insights that can guide the development of antivirals against CoVs.展开更多
Most deaths from the COVID-19 pandemic are due to acute respiratory distress syndrome(ARDS)-related respiratory failure.Cytokine storms and oxidative stress are the major players in ARDS development during respiratory...Most deaths from the COVID-19 pandemic are due to acute respiratory distress syndrome(ARDS)-related respiratory failure.Cytokine storms and oxidative stress are the major players in ARDS development during respiratory virus infections.However,it is still unknown how oxidative stress is regulated by viral and host factors in response to SARS-CoV-2 infection.Here,we found that activation of NRF2/HMOX1 significantly suppressed SARS-CoV-2 replication in multiple cell types by producing the metabolite biliverdin,whereas SARS-CoV-2 impaired the NRF2/HMOX1 axis through the action of the nonstructural viral protein NSP14.Mechanistically,NSP14 interacts with the catalytic domain of the NAD-dependent deacetylase Sirtuin 1(SIRT1)and inhibits its ability to activate the NRF2/HMOX1 pathway.Furthermore,both genetic and pharmaceutical evidence corroborated the novel antiviral activity of SIRT1 against SARS-CoV-2.Therefore,our findings reveal a novel mechanism by which SARS-CoV-2 dysregulates the host antioxidant defense system and emphasize the vital role played by the SIRT1/NRF2 axis in host defense against SARS-CoV-2.展开更多
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.31870135,31600116)the“1000 Talent Plan”of Sichuan Province(No.980)。
文摘The outbreak of coronavirus disease 2019(COVID-19)caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is a serious global health threat.This raises an urgent need for the development of effective drugs against the deadly disease.SARS-CoV-2 non-structural protein 14(NSP14)carrying RNA cap guanine N7-methyltransferase and 30-50 exoribonuclease activities could be a potential drug target for intervention.NSP14 of SARS-CoV-2 shares 98.7%of similarity with the one(PDB 5NFY)of acute respiratory syndrome(SARS)by ClustalW.Then,the SARS-CoV-2 NSP14 structures were modelled by Modeller 9.18 using SARS NSP14(PDB 5NFY)as template for virtual screening.Based on the docking score from AutoDock Vina1.1.2,18 small molecule drugs were selected for further evaluation.Based on the 5 ns MD simulation trajectory,binding free energy(DG)was calculated by MM/GBSA method.The calculated binding free energies of Saquinavir,Hypericin,Baicalein and Bromocriptine for the N-terminus of the homology model wereà37.2711±3.2160,à30.1746±3.1914,à23.8953±4.4800,andà34.1350±4.3683 kcal/mol,respectively,while the calculated binding free energies wereà60.2757±4.7708,à30.9955±2.9975,à46.3099±3.5689,andà59.8104±3.5389 kcal/mol,respectively,when binding to the C-terminus.Thus,the compounds including Saquinavir,Hypericin,Baicalein and Bromocriptine could bind to the N-terminus and C-terminus of the homology model of the SARS-CoV-2 NSP14,providing a candidate drug against SARS-CoV-2 for further study.
基金This work was supported by grants from the National Key R&D Program of China(2018YFD0500103 and 2017YFD0501100)the Chinese Academy of Agricultural Science and Technology Innovation Project(CAAS-ASTIP-2021-LVRI and Y2017JC55)Central Public-interest Scientific Institution Basal Research Fund(1610312016013 and 1610312017003).
文摘Coronaviruses(CoVs)are a group of related enveloped RNA viruses that have severe consequences in a wide variety of animals by causing respiratory,enteric or systemic diseases.Porcine epidemic diarrhea virus(PEDV)is an economically important CoV distributed worldwide that causes diarrhea in pigs.nsp14 is a nonstructural protein of PEDV that is involved in regulation of innate immunity and viral replication.However,the function and mechanism by which nsp14 modulates and manipulates host immune responses remain largely unknown.Here,we report that PEDV nsp14 is an NF-κB pathway antagonist.Overexpression PEDV nsp14 protein remarkably decreases SeV-,poly(I:C)-and TNF-α-induced NF-κB activation.Meanwhile,expression of proinflammatory cytokines is suppressed by nspl4.nsp14 inhibits the phosphorylation of IKKs by interacting with IKKs and p65.Furthermore,nsp14 suppresses TNF-α-induced phosphorylation and nuclear import of p65.Overexpression nsp14 considerably increases PEDV replication.These results suggest a novel mechanism employed by PEDV to suppress the host antiviral response,providing insights that can guide the development of antivirals against CoVs.
基金National Institute of Health(NIH)grants(AI069120,AI158154 and AI149718)the UCLA AIDS Institute and UCLA David Geffen School of Medicine-Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research Award Program.
文摘Most deaths from the COVID-19 pandemic are due to acute respiratory distress syndrome(ARDS)-related respiratory failure.Cytokine storms and oxidative stress are the major players in ARDS development during respiratory virus infections.However,it is still unknown how oxidative stress is regulated by viral and host factors in response to SARS-CoV-2 infection.Here,we found that activation of NRF2/HMOX1 significantly suppressed SARS-CoV-2 replication in multiple cell types by producing the metabolite biliverdin,whereas SARS-CoV-2 impaired the NRF2/HMOX1 axis through the action of the nonstructural viral protein NSP14.Mechanistically,NSP14 interacts with the catalytic domain of the NAD-dependent deacetylase Sirtuin 1(SIRT1)and inhibits its ability to activate the NRF2/HMOX1 pathway.Furthermore,both genetic and pharmaceutical evidence corroborated the novel antiviral activity of SIRT1 against SARS-CoV-2.Therefore,our findings reveal a novel mechanism by which SARS-CoV-2 dysregulates the host antioxidant defense system and emphasize the vital role played by the SIRT1/NRF2 axis in host defense against SARS-CoV-2.
