The spike protein(S)of SARS-CoV-2 is responsible for viral attachment and entry,thus a major factor for host suscep-tibility,tissue tropism,virulence and pathogenicity.The S is divided with S1 and S2 region,and the S1...The spike protein(S)of SARS-CoV-2 is responsible for viral attachment and entry,thus a major factor for host suscep-tibility,tissue tropism,virulence and pathogenicity.The S is divided with S1 and S2 region,and the S1 contains the receptor-binding domain(RBD),while the S2 contains the hydrophobic fusion domain for the entry into the host cell.Numerous host proteases have been implicated in the activation of SARS-CoV-2 S through various c leavage sites.In this article,we review host proteases including furin,trypsin,transmembrane protease serine 2(TMPRSS2)and cathepsins in the activation of SARS-CoV-2 S.Many betacoronaviruses including SARS-CoV-2 have polybasic residues at the S1/S2 site which is subjected to the cleavage by furin.The S1/S2 cleavage facilitates more assessable RBD to the receptor ACE2,and the binding triggers further conformational changes and exposure of the S2'site to proteases such as type Il transmembrane serine proteases(TTPRs)including TMPRSS2.In the presence of TMPRSS2 on the target cells,SARS-CoV-2 can utilize a direct entry route by fusion of the viral envelope to the cellular membrane.In the absence of TMPRSS2,SARS-CoV-2 enter target cells via endosomes where multiple cathepsins cleave the S for the successful entry.Additional host proteases involved in the cleavage of the S were discussed.This article also includes roles of 3C-like protease inhibitors which have inhibitory activity against cathepsin L in the entry of SARS-CoV-2,and discussed the dual roles of such inhibitors in virus replication.展开更多
Introduction: Omicron is a highly divergent variant of concern (VOCs) of a severe acute respiratory syndrome SARS-CoV-2. It carries a high number of mutations in its spike protein hence;it is more transmissible in the...Introduction: Omicron is a highly divergent variant of concern (VOCs) of a severe acute respiratory syndrome SARS-CoV-2. It carries a high number of mutations in its spike protein hence;it is more transmissible in the community by immune evasion mechanisms. Due to mutation within S gene, most Omicron variants have reported S gene target failure (SGTF) with some commercially available PCR kits. Such diagnostic features can be used as markers to screen Omicron. However, Whole Genome Sequencing (WGS) is the only gold standard approach to confirm novel microorganisms at genetically level as similar mutations can also be found in other variants that are circulating at low frequencies worldwide. This Retrospective study is aimed to assess RT-PCR sensitivity in the detection of S gene target failure in comparison with whole genome sequencing to detect variants of Omicron. Methods: We have analysed retrospective data of SARS-CoV-2 positive RT-PCR samples for S gene target failure (SGTF) with TaqPath COVID-19 RT-PCR Combo Kit (ThermoFisher) and combined with sequencing technologies to study the emerged pattern of SARS-CoV-2 variants during third wave at the tertiary care centre, Surat. Results: From the first day of December 2021 till the end of February 2022, a total of 321,803 diagnostic RT-PCR tests for SARS-CoV-2 were performed, of which 20,566 positive cases were reported at our tertiary care centre with an average cumulative positivity of 6.39% over a period of three months. In the month of December 21 samples characterized by the SGTF (70/129) were suggestive of being infected by the Omicron variant and identified as Omicron (B.1.1.529 lineage) when sequence. In the month of January, we analysed a subset of samples (n = 618) with SGTF (24%) and without SGTF (76%) with Ct values Conclusions: During the COVID-19 pandemic, it took almost more than 15 days to diagnose infection and identify pathogen by sequencing technology. In contrast to that molecular assay provided quick identification with the help of SGTF phenomenon within 5 hours of duration. This strategy helps scientists and health policymakers for the quick isolation and identification of clusters. That ultimately results in a decreased transmission of pathogen among the community.展开更多
Background: Omicron JN.1 has become the dominant SARS-CoV-2 variant in recent months. JN.1 has the highest number of amino acid mutations in its receptor binding domain (RBD) and has acquired a hallmark L455S mutation...Background: Omicron JN.1 has become the dominant SARS-CoV-2 variant in recent months. JN.1 has the highest number of amino acid mutations in its receptor binding domain (RBD) and has acquired a hallmark L455S mutation. The immune evasion capability of JN.1 is a subject of scientific investigation. The US CDC used SGTF of TaqPath COVID-19 Combo Kit RT-qPCR as proxy indicator of JN.1 infections for evaluation of the effectiveness of updated monovalent XBB.1.5 COVID-19 vaccines against JN.1 and recommended that all persons aged ≥ 6 months should receive an updated COVID-19 vaccine dose. Objective: Recommend Sanger sequencing instead of proxy indicator to diagnose JN.1 infections to generate the data based on which guidelines are made to direct vaccination policies. Methods: The RNA in nasopharyngeal swab specimens from patients with clinical respiratory infection was subjected to nested RT-PCR, targeting a 398-base segment of the N-gene and a 445-base segment of the RBD of SARS-CoV-2 for amplification. The nested PCR amplicons were sequenced. The DNA sequences were analyzed for amino acid mutations. Results: The N-gene sequence showed R203K, G204R and Q229K, the 3 mutations associated with Omicron BA.2.86 (+JN.1). The RBD sequence showed 24 of the 26 known amino acid mutations, including the hallmark L455S mutation for JN.1 and the V483del for BA.2.86 lineage. Conclusions: Sanger sequencing of a 445-base segment of the SARS-CoV-2 RBD is useful for accurate determination of emerging variants. The CDC may consider using Sanger sequencing of the RBD to diagnose JN.1 infections for statistical analysis in making vaccination policies.展开更多
Objective Late 2019 witnessed the outbreak and widespread transmission of coronavirus disease 2019(COVID-19),a new,highly contagious disease caused by novel severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)....Objective Late 2019 witnessed the outbreak and widespread transmission of coronavirus disease 2019(COVID-19),a new,highly contagious disease caused by novel severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Consequently,considerable attention has been paid to the development of new diagnostic tools for the early detection of SARS-CoV-2.Methods In this study,a new poly-N-isopropylacrylamide microgel-based electrochemical sensor was explored to detect the SARS-CoV-2 spike protein(S protein)in human saliva.The microgel was composed of a copolymer of N-isopropylacrylamide and acrylic acid,and gold nanoparticles were encapsulated within the microgel through facile and economical fabrication.The electrochemical performance of the sensor was evaluated through differential pulse voltammetry.Results Under optimal experimental conditions,the linear range of the sensor was 10-13-10-9 mg/m L,whereas the detection limit was 9.55 fg/mL.Furthermore,the S protein was instilled in artificial saliva as the infected human saliva model,and the sensing platform showed satisfactory detection capability.Conclusion The sensing platform exhibited excellent specificity and sensitivity in detecting spike protein,indicating its potential application for the time-saving and inexpensive detection of SARS-CoV-2.展开更多
Endoplasmic reticulum stress and mitochondrial dysfunction play important roles in Parkinson s disease,but the regulato ry mechanism remains elusive.Prohibitin-2(PHB2)is a newly discove red autophagy receptor in the m...Endoplasmic reticulum stress and mitochondrial dysfunction play important roles in Parkinson s disease,but the regulato ry mechanism remains elusive.Prohibitin-2(PHB2)is a newly discove red autophagy receptor in the mitochondrial inner membrane,and its role in Parkinson’s disease remains unclear.Protein kinase R(PKR)-like endoplasmic reticulum kinase(PERK)is a factor that regulates cell fate during endoplasmic reticulum stress.Parkin is regulated by PERK and is a target of the unfolded protein response.It is unclear whether PERK regulates PHB2-mediated mitophagy thro ugh Parkin.In this study,we established a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced mouse model of Parkinson’s disease.We used adeno-associated virus to knockdown PHB2 expression.Our res ults showed that loss of dopaminergic neurons and motor deficits were aggravated in the MPTP-induced mouse model of Parkinson’s disease.Ove rexpression of PHB2 inhibited these abnormalities.We also established a 1-methyl-4-phenylpyridine(MPP+)-induced SH-SY5Y cell model of Parkinson’s disease.We found that ove rexpression of Parkin increased co-localization of PHB2 and microtubule-associated protein 1 light chain 3,and promoted mitophagy.In addition,MPP+regulated Parkin involvement in PHB2-mediated mitophagy through phosphorylation of PERK.These findings suggest that PHB2 participates in the development of Parkinson’s disease by intera cting with endoplasmic reticulum stress and Parkin.展开更多
Coronavirus disease 2019(COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2(SARS-Co V-2), has spread rapidly worldwide with high rates of transmission and substantial mortality. To date, how...Coronavirus disease 2019(COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2(SARS-Co V-2), has spread rapidly worldwide with high rates of transmission and substantial mortality. To date, however, no effective treatments or enough vaccines for COVID-19 are available. The roles of angiotensin converting enzyme 2(ACE2) and spike protein in the treatment of COVID-19 are major areas of research. In this study, we explored the potential of ACE2 and spike protein as targets for the development of antiviral agents against SARS-Co V-2. We analyzed clinical data, genetic data, and receptor binding capability.Clinical data revealed that COVID-19 patients with comorbidities related to an abnormal reninangiotensin system exhibited more early symptoms and poorer prognoses. However, the relationship between ACE2 expression and COVID-19progression is still not clear. Furthermore, if ACE2 is not a good targetable protein, it would not be applicable across a wide range of populations. The spike-S1 receptor-binding domain that interacts with ACE2 showed various amino acid mutations based on sequence analysis. We identified two spike-S1 point mutations(V354 F and V470 A) by receptorligand docking and binding enzyme-linked immunosorbent assays. These variants enhanced the binding of the spike protein to ACE2 receptors and were potentially associated with increased infectivity. Importantly, the number of patients infected with the V354 F and V470 A mutants has increased with the development of the SARS-Co V-2 pandemic. These results suggest that ACE2 and spike-S1 are likely not ideal targets for the design of peptide drugs to treat COVID-19 in different populations.展开更多
COVID-19 is a global pandemic that has claimed millions of lives. This disease is caused by a coronavirus, SARS-CoV-2, which requires the binding of its spike protein to angiotensin-converting enzyme 2 (ACE2) for infe...COVID-19 is a global pandemic that has claimed millions of lives. This disease is caused by a coronavirus, SARS-CoV-2, which requires the binding of its spike protein to angiotensin-converting enzyme 2 (ACE2) for infection of the host cell. <em>Morinda citrifolia</em> (noni) fruit juice has antiviral activity that involves enhancement of immune system function. SARS-CoV-2 spike-ACE2 interaction experiments were carried out to further investigate the antiviral properties of noni juice and its major iridoids. Noni juice inhibited binding by approximately 69%. Scandoside was the most active of the three iridoids evaluated, reducing average spike protein-ACE2 interaction by 79.25%. The iridoids worked synergistically towards inhibiting spike protein binding when assayed together, improving activity by more than 22% above the expected level. But the modest activity of the most abundant iridoid, deacetylasperulosidic acid, indicates that other phytochemicals (<em>i.e</em>. scopoletin, quercetin, rutin and kaempferol) are also involved. Our results suggest that the presence of several biological active phytochemicals in noni juice enhances resistance to SARS-CoV-2 by interfering with its ability to bind ACE2. This is a new and significant anti-viral mechanism of noni juice that does not directly involve its immunomodulatory properties.展开更多
The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), had caused over 382 million cases and over 2.7 million deaths globally as of 23 March 2021. By ...The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), had caused over 382 million cases and over 2.7 million deaths globally as of 23 March 2021. By that date, at least 10 SARS-CoV-2 variants had emerged. The transmissibility and lethality of the variants are higher than those of the Wuhan reference strain. Therefore, a universal vaccine for the reference strain and all variants (present and future) is indispensable. The coronavirus envelope (E) protein is an integral membrane protein crucial to the viral lifecycle and the pathogenesis of coronaviruses. The SARS-CoV-2 E protein has a postsynaptic density protein 95/Drosophila disc large tumor suppressor/zonula occludens-1 (PDZ) binding motif (PBM), and its interaction with PDZ-domain-2 of the human tight junction protein may interrupt the integrity of lung epithelium. Furthermore, the SARS-CoV-2 E protein itself is a homopentameric cation channel viroporin, which may be involved in viral release. This protein is thus a potential target for the development of a universal COVID-19 vaccine, because of its highly conserved amino acid sequence. The variant mutations occur mainly in the spike protein, and conservation of E protein remained in most Variants of Concern (VOC). Only one of the extant VOC have mutations in the E protein that P71L mutation occurs in the South African variant 501Y.V2 (B.1.351). If a vaccine is designed to target E protein, two scenarios are possible: 1) SARS-CoV-2 maintains a highly conserved E protein amino acid sequence, rendering the virus consistently or permanently susceptible to the vaccine;or 2) the E protein mutates and new variants evolve accordingly. In scenario 2, the tertiary structure and function of the E protein homopentameric cation channel viroporin, PBM, or other aspects affecting pathogenicity would be attenuated. Either scenario would thus ameliorate the pandemic. I therefore propose that a vaccine targeting the SARS-CoV-2 E protein would be effective against the Wuhan reference strain and all current and future SARS-CoV-2 variants. Efforts to create E protein-based vaccines are ongoing. Further research and clinical trials are needed to realize this universal COVID-19 vaccine.展开更多
基金National Institutes of Health(NIH)(grants R01 A/130092 and Al161085).
文摘The spike protein(S)of SARS-CoV-2 is responsible for viral attachment and entry,thus a major factor for host suscep-tibility,tissue tropism,virulence and pathogenicity.The S is divided with S1 and S2 region,and the S1 contains the receptor-binding domain(RBD),while the S2 contains the hydrophobic fusion domain for the entry into the host cell.Numerous host proteases have been implicated in the activation of SARS-CoV-2 S through various c leavage sites.In this article,we review host proteases including furin,trypsin,transmembrane protease serine 2(TMPRSS2)and cathepsins in the activation of SARS-CoV-2 S.Many betacoronaviruses including SARS-CoV-2 have polybasic residues at the S1/S2 site which is subjected to the cleavage by furin.The S1/S2 cleavage facilitates more assessable RBD to the receptor ACE2,and the binding triggers further conformational changes and exposure of the S2'site to proteases such as type Il transmembrane serine proteases(TTPRs)including TMPRSS2.In the presence of TMPRSS2 on the target cells,SARS-CoV-2 can utilize a direct entry route by fusion of the viral envelope to the cellular membrane.In the absence of TMPRSS2,SARS-CoV-2 enter target cells via endosomes where multiple cathepsins cleave the S for the successful entry.Additional host proteases involved in the cleavage of the S were discussed.This article also includes roles of 3C-like protease inhibitors which have inhibitory activity against cathepsin L in the entry of SARS-CoV-2,and discussed the dual roles of such inhibitors in virus replication.
文摘Introduction: Omicron is a highly divergent variant of concern (VOCs) of a severe acute respiratory syndrome SARS-CoV-2. It carries a high number of mutations in its spike protein hence;it is more transmissible in the community by immune evasion mechanisms. Due to mutation within S gene, most Omicron variants have reported S gene target failure (SGTF) with some commercially available PCR kits. Such diagnostic features can be used as markers to screen Omicron. However, Whole Genome Sequencing (WGS) is the only gold standard approach to confirm novel microorganisms at genetically level as similar mutations can also be found in other variants that are circulating at low frequencies worldwide. This Retrospective study is aimed to assess RT-PCR sensitivity in the detection of S gene target failure in comparison with whole genome sequencing to detect variants of Omicron. Methods: We have analysed retrospective data of SARS-CoV-2 positive RT-PCR samples for S gene target failure (SGTF) with TaqPath COVID-19 RT-PCR Combo Kit (ThermoFisher) and combined with sequencing technologies to study the emerged pattern of SARS-CoV-2 variants during third wave at the tertiary care centre, Surat. Results: From the first day of December 2021 till the end of February 2022, a total of 321,803 diagnostic RT-PCR tests for SARS-CoV-2 were performed, of which 20,566 positive cases were reported at our tertiary care centre with an average cumulative positivity of 6.39% over a period of three months. In the month of December 21 samples characterized by the SGTF (70/129) were suggestive of being infected by the Omicron variant and identified as Omicron (B.1.1.529 lineage) when sequence. In the month of January, we analysed a subset of samples (n = 618) with SGTF (24%) and without SGTF (76%) with Ct values Conclusions: During the COVID-19 pandemic, it took almost more than 15 days to diagnose infection and identify pathogen by sequencing technology. In contrast to that molecular assay provided quick identification with the help of SGTF phenomenon within 5 hours of duration. This strategy helps scientists and health policymakers for the quick isolation and identification of clusters. That ultimately results in a decreased transmission of pathogen among the community.
文摘Background: Omicron JN.1 has become the dominant SARS-CoV-2 variant in recent months. JN.1 has the highest number of amino acid mutations in its receptor binding domain (RBD) and has acquired a hallmark L455S mutation. The immune evasion capability of JN.1 is a subject of scientific investigation. The US CDC used SGTF of TaqPath COVID-19 Combo Kit RT-qPCR as proxy indicator of JN.1 infections for evaluation of the effectiveness of updated monovalent XBB.1.5 COVID-19 vaccines against JN.1 and recommended that all persons aged ≥ 6 months should receive an updated COVID-19 vaccine dose. Objective: Recommend Sanger sequencing instead of proxy indicator to diagnose JN.1 infections to generate the data based on which guidelines are made to direct vaccination policies. Methods: The RNA in nasopharyngeal swab specimens from patients with clinical respiratory infection was subjected to nested RT-PCR, targeting a 398-base segment of the N-gene and a 445-base segment of the RBD of SARS-CoV-2 for amplification. The nested PCR amplicons were sequenced. The DNA sequences were analyzed for amino acid mutations. Results: The N-gene sequence showed R203K, G204R and Q229K, the 3 mutations associated with Omicron BA.2.86 (+JN.1). The RBD sequence showed 24 of the 26 known amino acid mutations, including the hallmark L455S mutation for JN.1 and the V483del for BA.2.86 lineage. Conclusions: Sanger sequencing of a 445-base segment of the SARS-CoV-2 RBD is useful for accurate determination of emerging variants. The CDC may consider using Sanger sequencing of the RBD to diagnose JN.1 infections for statistical analysis in making vaccination policies.
基金supported by Key Research and Development Project of Hubei Province[Number 2020BCB022]Opening Fund of State Key Laboratory of Virology of Wuhan University[grant number 2022KF002]+2 种基金Royal Society International Exchanges Scheme[IECNSFC201116]The Academy of Medical Sciences/Wellcome Trust[Springboard grantSBF007100054]。
文摘Objective Late 2019 witnessed the outbreak and widespread transmission of coronavirus disease 2019(COVID-19),a new,highly contagious disease caused by novel severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Consequently,considerable attention has been paid to the development of new diagnostic tools for the early detection of SARS-CoV-2.Methods In this study,a new poly-N-isopropylacrylamide microgel-based electrochemical sensor was explored to detect the SARS-CoV-2 spike protein(S protein)in human saliva.The microgel was composed of a copolymer of N-isopropylacrylamide and acrylic acid,and gold nanoparticles were encapsulated within the microgel through facile and economical fabrication.The electrochemical performance of the sensor was evaluated through differential pulse voltammetry.Results Under optimal experimental conditions,the linear range of the sensor was 10-13-10-9 mg/m L,whereas the detection limit was 9.55 fg/mL.Furthermore,the S protein was instilled in artificial saliva as the infected human saliva model,and the sensing platform showed satisfactory detection capability.Conclusion The sensing platform exhibited excellent specificity and sensitivity in detecting spike protein,indicating its potential application for the time-saving and inexpensive detection of SARS-CoV-2.
基金supported by the Key Science and Technology Research of Henan Province,No.222102310351(to JW)Luoyang 2022 Medical and Health Guiding Science and Technology Plan Project,No.2022057Y(to JY)Henan Medical Science and Technology Research Program Province-Ministry Co-sponsorship,No.SBGJ202002099(to JY)。
文摘Endoplasmic reticulum stress and mitochondrial dysfunction play important roles in Parkinson s disease,but the regulato ry mechanism remains elusive.Prohibitin-2(PHB2)is a newly discove red autophagy receptor in the mitochondrial inner membrane,and its role in Parkinson’s disease remains unclear.Protein kinase R(PKR)-like endoplasmic reticulum kinase(PERK)is a factor that regulates cell fate during endoplasmic reticulum stress.Parkin is regulated by PERK and is a target of the unfolded protein response.It is unclear whether PERK regulates PHB2-mediated mitophagy thro ugh Parkin.In this study,we established a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced mouse model of Parkinson’s disease.We used adeno-associated virus to knockdown PHB2 expression.Our res ults showed that loss of dopaminergic neurons and motor deficits were aggravated in the MPTP-induced mouse model of Parkinson’s disease.Ove rexpression of PHB2 inhibited these abnormalities.We also established a 1-methyl-4-phenylpyridine(MPP+)-induced SH-SY5Y cell model of Parkinson’s disease.We found that ove rexpression of Parkin increased co-localization of PHB2 and microtubule-associated protein 1 light chain 3,and promoted mitophagy.In addition,MPP+regulated Parkin involvement in PHB2-mediated mitophagy through phosphorylation of PERK.These findings suggest that PHB2 participates in the development of Parkinson’s disease by intera cting with endoplasmic reticulum stress and Parkin.
基金supported by the National Key Research and Development Program of China (2018YFD0900602)National Natural Science Foundation of China (31970388, 31701234)+3 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)Natural Science Foundation of the Jiangsu Higher Education Institutions (17KJB180006)Natural Science Foundation from Jiangsu Province (BK20160043, BK20151546, 15KJA180004and BK20171035)Jiangsu Distinguished Professor Funding。
文摘Coronavirus disease 2019(COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2(SARS-Co V-2), has spread rapidly worldwide with high rates of transmission and substantial mortality. To date, however, no effective treatments or enough vaccines for COVID-19 are available. The roles of angiotensin converting enzyme 2(ACE2) and spike protein in the treatment of COVID-19 are major areas of research. In this study, we explored the potential of ACE2 and spike protein as targets for the development of antiviral agents against SARS-Co V-2. We analyzed clinical data, genetic data, and receptor binding capability.Clinical data revealed that COVID-19 patients with comorbidities related to an abnormal reninangiotensin system exhibited more early symptoms and poorer prognoses. However, the relationship between ACE2 expression and COVID-19progression is still not clear. Furthermore, if ACE2 is not a good targetable protein, it would not be applicable across a wide range of populations. The spike-S1 receptor-binding domain that interacts with ACE2 showed various amino acid mutations based on sequence analysis. We identified two spike-S1 point mutations(V354 F and V470 A) by receptorligand docking and binding enzyme-linked immunosorbent assays. These variants enhanced the binding of the spike protein to ACE2 receptors and were potentially associated with increased infectivity. Importantly, the number of patients infected with the V354 F and V470 A mutants has increased with the development of the SARS-Co V-2 pandemic. These results suggest that ACE2 and spike-S1 are likely not ideal targets for the design of peptide drugs to treat COVID-19 in different populations.
文摘COVID-19 is a global pandemic that has claimed millions of lives. This disease is caused by a coronavirus, SARS-CoV-2, which requires the binding of its spike protein to angiotensin-converting enzyme 2 (ACE2) for infection of the host cell. <em>Morinda citrifolia</em> (noni) fruit juice has antiviral activity that involves enhancement of immune system function. SARS-CoV-2 spike-ACE2 interaction experiments were carried out to further investigate the antiviral properties of noni juice and its major iridoids. Noni juice inhibited binding by approximately 69%. Scandoside was the most active of the three iridoids evaluated, reducing average spike protein-ACE2 interaction by 79.25%. The iridoids worked synergistically towards inhibiting spike protein binding when assayed together, improving activity by more than 22% above the expected level. But the modest activity of the most abundant iridoid, deacetylasperulosidic acid, indicates that other phytochemicals (<em>i.e</em>. scopoletin, quercetin, rutin and kaempferol) are also involved. Our results suggest that the presence of several biological active phytochemicals in noni juice enhances resistance to SARS-CoV-2 by interfering with its ability to bind ACE2. This is a new and significant anti-viral mechanism of noni juice that does not directly involve its immunomodulatory properties.
文摘The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), had caused over 382 million cases and over 2.7 million deaths globally as of 23 March 2021. By that date, at least 10 SARS-CoV-2 variants had emerged. The transmissibility and lethality of the variants are higher than those of the Wuhan reference strain. Therefore, a universal vaccine for the reference strain and all variants (present and future) is indispensable. The coronavirus envelope (E) protein is an integral membrane protein crucial to the viral lifecycle and the pathogenesis of coronaviruses. The SARS-CoV-2 E protein has a postsynaptic density protein 95/Drosophila disc large tumor suppressor/zonula occludens-1 (PDZ) binding motif (PBM), and its interaction with PDZ-domain-2 of the human tight junction protein may interrupt the integrity of lung epithelium. Furthermore, the SARS-CoV-2 E protein itself is a homopentameric cation channel viroporin, which may be involved in viral release. This protein is thus a potential target for the development of a universal COVID-19 vaccine, because of its highly conserved amino acid sequence. The variant mutations occur mainly in the spike protein, and conservation of E protein remained in most Variants of Concern (VOC). Only one of the extant VOC have mutations in the E protein that P71L mutation occurs in the South African variant 501Y.V2 (B.1.351). If a vaccine is designed to target E protein, two scenarios are possible: 1) SARS-CoV-2 maintains a highly conserved E protein amino acid sequence, rendering the virus consistently or permanently susceptible to the vaccine;or 2) the E protein mutates and new variants evolve accordingly. In scenario 2, the tertiary structure and function of the E protein homopentameric cation channel viroporin, PBM, or other aspects affecting pathogenicity would be attenuated. Either scenario would thus ameliorate the pandemic. I therefore propose that a vaccine targeting the SARS-CoV-2 E protein would be effective against the Wuhan reference strain and all current and future SARS-CoV-2 variants. Efforts to create E protein-based vaccines are ongoing. Further research and clinical trials are needed to realize this universal COVID-19 vaccine.
