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1.
Fundamental Research ; 2023.
Article in English | ScienceDirect | ID: covidwho-2311541

ABSTRACT

Combinatorial drug therapies are generally more effective than monotherapies in treating viral infections. However, it is critical for dose optimization to maximize the efficacy and minimize side effects. Although various strategies have been deviseenchmark functions is available at Github repositoryd to accelerate the optimization process, their efficiencies were limited by the high noises and suboptimal reproducibility of biological assays. With conventional methods, variances among the replications are used to evaluate the errors of the readouts alone rather than actively participating in the optimization. Herein, we present the Regression Modeling Enabled by Monte Carlo Method (ReMEMC) algorithm for rapid identification of effective combinational therapies. ReMEMC transforms the sample variations into probability distributions of the regression coefficients and predictions. In silico simulations revealed that ReMEMC outperformed conventional regression methods in benchmark problems, and demonstrated its superior robustness against experimental noises. Using COVID-19 as a model disease, ReMEMC successfully identified an optimal 3-drug combination among 10 anti-SARS-CoV-2 drug compounds within two rounds of experiments. The optimal combination showed 2-log and 3-log higher load reduction than non-optimized combinations and monotherapy, respectively. Further workflow refinement allowed identification of personalized drug combinational therapies within 5 days. The strategy may serve as an efficient and universal tool for dose combination optimization.

2.
J Control Release ; 358: 128-141, 2023 06.
Article in English | MEDLINE | ID: covidwho-2303394

ABSTRACT

Neutralising monoclonal antibody (mAb) is an important weapon in our arsenal for combating respiratory viral infections. However, the effectiveness of neutralising mAb has been impeded by the rapid emergence of mutant variants. Early administration of broad-spectrum mAb with improved delivery efficiency can potentially enhance efficacy and patient outcomes. WKS13 is a humanised mAb which was previously demonstrated to exhibit broad-spectrum activity against SARS-CoV-2 variants. In this study, a dual targeting formulation strategy was designed to deliver WKS13 to both the nasal cavity and lower airways, the two critical sites of infection caused by SARS-CoV-2. Dry powders of WKS13 were first prepared by spray drying, with cyclodextrin used as stabiliser excipient. Two-fluid nozzle (TFN) was used to produce particles below 5 µm for lung deposition (C-TFN formulation) and ultrasonic nozzle (USN) was used to produce particles above 10 µm for nasal deposition (C-USN formulation). Gel electrophoresis and size exclusion chromatography studies showed that the structural integrity of mAb was successfully preserved with no sign of aggregation after spray drying. To achieve dual targeting property, C-TFN and C-USN were mixed at various ratios. The aerosolisation property of the mixed formulations dispersed from a nasal powder device was examined using a Next Generation Impactor (NGI) coupled with a glass expansion chamber. When the ratio of C-TFN in the mixed formulation increased, the fraction of particles deposited in the lung increased proportionally while the fraction of particles deposited in the nasal cavity decreased correspondingly. A customisable aerosol deposition profile could therefore be achieved by manipulating the mixing ratio between C-TFN and C-USN. Dual administration of C-TFN and C-USN powders to the lung and nasal cavity of hamsters, respectively, was effective in offering prophylactic protection against SARS-CoV-2 Delta variant. Viral loads in both the lung tissues and nasal wash were significantly reduced, and the efficacy was comparable to systemic administration of unformulated WKS13. Overall, dual targeting powder formulation of neutralising mAb is a promising approach for prophylaxis of respiratory viral infections. The ease and non-invasive administration of dual targeting nasal powder may facilitate the widespread distribution of neutralising mAb during the early stage of unpredictable outbreaks.


Subject(s)
Antibodies, Monoclonal , COVID-19 , Humans , Powders , SARS-CoV-2 , Respiratory Aerosols and Droplets , Administration, Inhalation , Particle Size , Dry Powder Inhalers
3.
Cell Rep Med ; 3(9): 100743, 2022 09 20.
Article in English | MEDLINE | ID: covidwho-2254238

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron BA.2 was a dominant circulating SARS-CoV-2 variant worldwide. Recent reports hint that BA.2 is similarly potent regarding antibody evasion but may be more transmissible than BA.1. The pathogenicity of BA.2 remains unclear and is of critical public health significance. Here we investigated the virological features and pathogenicity of BA.2 with in vitro and in vivo models. We show that BA.2 is less dependent on transmembrane protease serine 2 (TMPRSS2) for virus entry in comparison with BA.1 in vitro. In K18-hACE2 mice, BA.2 replicates more efficiently than BA.1 in the nasal turbinates and replicates marginally less efficiently in the lungs, leading to decreased body weight loss and improved survival. Our study indicates that BA.2 is similarly attenuated in lungs compared with BA.1 but is potentially more transmissible because of its better replication at the nasal turbinates.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Humans , Mice , SARS-CoV-2/genetics , Serine , Virulence
4.
J Med Virol ; 95(2): e28585, 2023 02.
Article in English | MEDLINE | ID: covidwho-2289067

ABSTRACT

Genome-wide association study (GWAS) could identify host genetic factors associated with coronavirus disease 2019 (COVID-19). The genes or functional DNA elements through which genetic factors affect COVID-19 remain uncharted. The expression quantitative trait locus (eQTL) provides a path to assess the correlation between genetic variations and gene expression. Here, we firstly annotated GWAS data to describe genetic effects, obtaining genome-wide mapped genes. Subsequently, the genetic mechanisms and characteristics of COVID-19 were investigated by an integrated strategy that included three GWAS-eQTL analysis approaches. It was found that 20 genes were significantly associated with immunity and neurological disorders, including prior and novel genes such as OAS3 and LRRC37A2. The findings were then replicated in single-cell datasets to explore the cell-specific expression of causal genes. Furthermore, associations between COVID-19 and neurological disorders were assessed as a causal relationship. Finally, the effects of causal protein-coding genes of COVID-19 were discussed using cell experiments. The results revealed some novel COVID-19-related genes to emphasize disease characteristics, offering a broader insight into the genetic architecture underlying the pathophysiology of COVID-19.


Subject(s)
COVID-19 , Genome-Wide Association Study , Humans , COVID-19/genetics , Quantitative Trait Loci , Genetic Predisposition to Disease , Polymorphism, Single Nucleotide
5.
Cell Rep Med ; 3(12): 100849, 2022 12 20.
Article in English | MEDLINE | ID: covidwho-2278940

ABSTRACT

Direct in vivo investigation of human placenta trophoblast's susceptibility to SARS-CoV-2 is challenging. Here we report that human trophoblast stem cells (hTSCs) and their derivatives are susceptible to SARS-CoV-2 infection, which reveals heterogeneity in hTSC cultures. Early syncytiotrophoblasts (eSTBs) generated from hTSCs have enriched transcriptomic features of peri-implantation trophoblasts, express high levels of angiotensin-converting enzyme 2 (ACE2), and are productively infected by SARS-CoV-2 and its Delta and Omicron variants to produce virions. Antiviral drugs suppress SARS-CoV-2 replication in eSTBs and antagonize the virus-induced blockage of STB maturation. Although less susceptible to SARS-CoV-2 infection, trophoblast organoids originating from hTSCs show detectable viral replication reminiscent of the uncommon placental infection. These findings implicate possible risk of COVID-19 infection in peri-implantation embryos, which may go unnoticed. Stem cell-derived human trophoblasts such as eSTBs can potentially provide unlimited amounts of normal and genome-edited cells and facilitate coronavirus research and antiviral discovery.


Subject(s)
COVID-19 , Pregnancy Complications, Infectious , Humans , Female , Pregnancy , SARS-CoV-2 , Trophoblasts , Placenta , Peptidyl-Dipeptidase A/genetics , Antiviral Agents/pharmacology
6.
Viruses ; 15(3)2023 03 06.
Article in English | MEDLINE | ID: covidwho-2253490

ABSTRACT

The emergence of new immune-evasive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and subvariants outpaces the development of vaccines specific against the dominant circulating strains. In terms of the only accepted immune correlate of protection, the inactivated whole-virion vaccine using wild-type SARS-CoV-2 spike induces a much lower serum neutralizing antibody titre against the Omicron subvariants. Since the inactivated vaccine given intramuscularly is one of the most commonly used coronavirus disease 2019 (COVID-19) vaccines in developing regions, we tested the hypothesis that intranasal boosting after intramuscular priming would provide a broader level of protection. Here, we showed that one or two intranasal boosts with the Fc-linked trimeric spike receptor-binding domain from wild-type SARS-CoV-2 can induce significantly higher serum neutralizing antibodies against wild-type SARS-CoV-2 and the Omicron subvariants, including BA.5.2 and XBB.1, with a lower titre in the bronchoalveolar lavage of vaccinated Balb/c mice than vaccination with four intramuscular doses of inactivated whole virion vaccine. The intranasally vaccinated K18-hACE2-transgenic mice also had a significantly lower nasal turbinate viral load, suggesting a better protection of the upper airway, which is the predilected site of infection by Omicron subvariants. This intramuscular priming and intranasal boosting approach that achieves broader cross-protection against Omicron variants and subvariants may lengthen the interval required for changing the vaccine immunogen from months to years.


Subject(s)
COVID-19 , Turbinates , Mice , Animals , SARS-CoV-2/genetics , Viral Load , COVID-19/prevention & control , Mice, Transgenic , Antibodies, Neutralizing , COVID-19 Vaccines , Mice, Inbred BALB C , Antibodies, Viral , Spike Glycoprotein, Coronavirus/genetics
7.
ACS Cent Sci ; 9(2): 217-227, 2023 Feb 22.
Article in English | MEDLINE | ID: covidwho-2241536

ABSTRACT

The 3C-like protease (3CLpro) is an essential enzyme for the replication of SARS-CoV-2 and other coronaviruses and thus is a target for coronavirus drug discovery. Nearly all inhibitors of coronavirus 3CLpro reported so far are covalent inhibitors. Here, we report the development of specific, noncovalent inhibitors of 3CLpro. The most potent one, WU-04, effectively blocks SARS-CoV-2 replications in human cells with EC50 values in the 10-nM range. WU-04 also inhibits the 3CLpro of SARS-CoV and MERS-CoV with high potency, indicating that it is a pan-inhibitor of coronavirus 3CLpro. WU-04 showed anti-SARS-CoV-2 activity similar to that of PF-07321332 (Nirmatrelvir) in K18-hACE2 mice when the same dose was administered orally. Thus, WU-04 is a promising drug candidate for coronavirus treatment.

8.
Sci Adv ; 9(3): eadd3867, 2023 Jan 20.
Article in English | MEDLINE | ID: covidwho-2239636

ABSTRACT

Successful severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection requires proteolytic cleavage of the viral spike protein. While the role of the host transmembrane protease serine 2 in SARS-CoV-2 infection is widely recognized, the involvement of other proteases capable of facilitating SARS-CoV-2 entry remains incompletely explored. Here, we show that multiple members from the membrane-type matrix metalloproteinase (MT-MMP) and a disintegrin and metalloproteinase families can mediate SARS-CoV-2 entry. Inhibition of MT-MMPs significantly reduces SARS-CoV-2 replication in vitro and in vivo. Mechanistically, we show that MT-MMPs can cleave SARS-CoV-2 spike and angiotensin-converting enzyme 2 and facilitate spike-mediated fusion. We further demonstrate that Omicron BA.1 has an increased efficiency on MT-MMP usage, while an altered efficiency on transmembrane serine protease usage for virus entry compared with that of ancestral SARS-CoV-2. These results reveal additional protease determinants for SARS-CoV-2 infection and enhance our understanding on the biology of coronavirus entry.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/metabolism , Peptide Hydrolases/metabolism , Proteolysis , Metalloproteases/metabolism , Virus Internalization
9.
J Med Virol ; 2022 Sep 02.
Article in English | MEDLINE | ID: covidwho-2236823

ABSTRACT

Increasing evidence supports inter-species transmission of SARS-CoV-2 variants from humans to domestic or wild animals during the ongoing COVID-19 pandemic, which is posing great challenges to epidemic control. Clarifying the host range of emerging SARS-CoV-2 variants will provide instructive information for the containment of viral spillover. The spike protein (S) of SARS-CoV-2 is the key determinant of receptor utilization, and therefore amino acid mutations on S will probably alter viral host range. Here, to evaluate the impact of S mutations, we tested 27 pseudoviruses of SARS-CoV-2 carrying different spike mutants by infecting Hela cells expressing different angiotensin-converting enzyme 2 (ACE2) orthologs from 20 animals. Of these 27 pseudoviruses, 20 bear single mutation and the other 7 were cloned from emerging SARS-CoV-2 variants, including D614G, Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Delta (B.1.617.2), Lambda (B.1.429), and Mu (B.1.621). Using pseudoviral reporter assay, we identified that the substitutions of T478I and N501Y enabled the pseudovirus to utilize chicken ACE2, indicating potential infectivity to avian species. Furthermore, the S mutants of real SARS-CoV-2 variants comprising N501Y showed significantly acquired abilities to infect cells expressing mouse ACE2, indicating a critical role of N501Y in expanding SARS-CoV-2 host range. In addition, A262S and T478I significantly enhanced the utilization of various mammal ACE2. In summary, our results indicated that T478I and N501Y substitutions were two S mutations important for receptor adaption of SARS-CoV-2, potentially contributing to the spillover of the virus to many other animal hosts. Therefore, more attention should be paid to SARS-CoV-2 variants with these two mutations.

10.
J Med Virol ; : e28326, 2022 Nov 21.
Article in English | MEDLINE | ID: covidwho-2233994

ABSTRACT

The initial severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron subvariants, BA.1 and BA.2, are being progressively displaced by BA.5 in many countries. To provide insight on the replacement of BA.2 by BA.5 as the dominant SARS-CoV-2 variant, we performed a comparative analysis of Omicron BA.2.12.1 and BA.5.2 variants in cell culture and hamster models. We found that BA.5.2 exhibited enhanced replicative kinetics over BA.2.12.1 in vitro and in vivo, which is evidenced by the dominant BA.5.2 viral genome detected at different time points, regardless of immune selection pressure with vaccine-induced serum antibodies. Utilizing reverse genetics, we constructed a mutant SARS-CoV-2 carrying spike F486V substitution, which is an uncharacterized mutation that concurrently discriminates Omicron BA.5.2 from BA.2.12.1 variant. We noticed that the 486th residue does not confer viral replication advantage to the virus. We also found that 486V displayed generally reduced immune evasion capacity when compared with its predecessor, 486F. However, the surge of fitness in BA.5.2 over BA.2.12.1 was not due to stand-alone F486V substitution but as a result of the combination of multiple mutations. Our study upholds the urgency for continuous monitoring of SARS-CoV-2 Omicron variants with enhanced replication fitness.

11.
ACS central science ; 2023.
Article in English | EuropePMC | ID: covidwho-2218690

ABSTRACT

The 3C-like protease (3CLpro) is an essential enzyme for the replication of SARS-CoV-2 and other coronaviruses and thus is a target for coronavirus drug discovery. Nearly all inhibitors of coronavirus 3CLpro reported so far are covalent inhibitors. Here, we report the development of specific, noncovalent inhibitors of 3CLpro. The most potent one, WU-04, effectively blocks SARS-CoV-2 replications in human cells with EC50 values in the 10-nM range. WU-04 also inhibits the 3CLpro of SARS-CoV and MERS-CoV with high potency, indicating that it is a pan-inhibitor of coronavirus 3CLpro. WU-04 showed anti-SARS-CoV-2 activity similar to that of PF-07321332 (Nirmatrelvir) in K18-hACE2 mice when the same dose was administered orally. Thus, WU-04 is a promising drug candidate for coronavirus treatment. A novel oral noncovalent inhibitor of 3C-like protease, named WU-04, was developed as a promising drug candidate for COVID-19 treatment.

12.
Protein Cell ; 14(1): 37-50, 2023 01.
Article in English | MEDLINE | ID: covidwho-2222720

ABSTRACT

The twenty-first century has already recorded more than ten major epidemics or pandemics of viral disease, including the devastating COVID-19. Novel effective antivirals with broad-spectrum coverage are urgently needed. Herein, we reported a novel broad-spectrum antiviral compound PAC5. Oral administration of PAC5 eliminated HBV cccDNA and reduced the large antigen load in distinct mouse models of HBV infection. Strikingly, oral administration of PAC5 in a hamster model of SARS-CoV-2 omicron (BA.1) infection significantly decreases viral loads and attenuates lung inflammation. Mechanistically, PAC5 binds to a pocket near Asp49 in the RNA recognition motif of hnRNPA2B1. PAC5-bound hnRNPA2B1 is extensively activated and translocated to the cytoplasm where it initiates the TBK1-IRF3 pathway, leading to the production of type I IFNs with antiviral activity. Our results indicate that PAC5 is a novel small-molecule agonist of hnRNPA2B1, which may have a role in dealing with emerging infectious diseases now and in the future.


Subject(s)
Antiviral Agents , Hepatitis B virus , Heterogeneous-Nuclear Ribonucleoprotein Group A-B , SARS-CoV-2 , Animals , Mice , Antiviral Agents/pharmacology , COVID-19 , Interferon Type I/metabolism , SARS-CoV-2/drug effects , Heterogeneous-Nuclear Ribonucleoprotein Group A-B/antagonists & inhibitors
13.
Viruses ; 15(2)2023 01 26.
Article in English | MEDLINE | ID: covidwho-2216969

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the coronavirus disease 2019 (COVID-19) pandemic that has caused disastrous effects on the society and human health globally. SARS-CoV-2 is a sarbecovirus in the Coronaviridae family with a positive-sense single-stranded RNA genome. It mainly replicates in the cytoplasm and viral components including RNAs and proteins can be sensed by pattern recognition receptors including toll-like receptors (TLRs), RIG-I-like receptors (RLRs), and NOD-like receptors (NLRs) that regulate the host innate and adaptive immune responses. On the other hand, the SARS-CoV-2 genome encodes multiple proteins that can antagonize the host immune response to facilitate viral replication. In this review, we discuss the current knowledge on host sensors and viral countermeasures against host innate immune response to provide insights on virus-host interactions and novel approaches to modulate host inflammation and antiviral responses.


Subject(s)
COVID-19 , Severe acute respiratory syndrome-related coronavirus , Humans , SARS-CoV-2/genetics , Cytoplasm , Host Microbial Interactions , RNA
14.
Nat Commun ; 13(1): 7907, 2022 12 23.
Article in English | MEDLINE | ID: covidwho-2185829

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic. Angiotensin-converting enzyme 2 (ACE2) is an entry receptor for SARS-CoV-2. The full-length membrane form of ACE2 (memACE2) undergoes ectodomain shedding to generate a shed soluble form (solACE2) that mediates SARS-CoV-2 entry via receptor-mediated endocytosis. Currently, it is not known how the physiological regulation of ACE2 shedding contributes to the etiology of COVID-19 in vivo. The present study identifies Membrane-type 1 Matrix Metalloproteinase (MT1-MMP) as a critical host protease for solACE2-mediated SARS-CoV-2 infection. SARS-CoV-2 infection leads to increased activation of MT1-MMP that is colocalized with ACE2 in human lung epithelium. Mechanistically, MT1-MMP directly cleaves memACE2 at M706-S to release solACE218-706 that binds to the SARS-CoV-2 spike proteins (S), thus facilitating cell entry of SARS-CoV-2. Human solACE218-706 enables SARS-CoV-2 infection in both non-permissive cells and naturally insusceptible C57BL/6 mice. Inhibition of MT1-MMP activities suppresses solACE2-directed entry of SARS-CoV-2 in human organoids and aged mice. Both solACE2 and circulating MT1-MMP are positively correlated in plasma of aged mice and humans. Our findings provide in vivo evidence demonstrating the contribution of ACE2 shedding to the etiology of COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2 , COVID-19 , Host-Pathogen Interactions , Matrix Metalloproteinase 14 , SARS-CoV-2 , Animals , Humans , Mice , Angiotensin-Converting Enzyme 2/metabolism , COVID-19/metabolism , COVID-19/virology , Mice, Inbred C57BL , Peptidyl-Dipeptidase A/metabolism , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/metabolism
15.
Cell Rep Med ; 3(10): 100774, 2022 10 18.
Article in English | MEDLINE | ID: covidwho-2050073

ABSTRACT

"Pan-coronavirus" antivirals targeting conserved viral components can be designed. Here, we show that the rationally engineered H84T-banana lectin (H84T-BanLec), which specifically recognizes high mannose found on viral proteins but seldom on healthy human cells, potently inhibits Middle East respiratory syndrome coronavirus (MERS-CoV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (including Omicron), and other human-pathogenic coronaviruses at nanomolar concentrations. H84T-BanLec protects against MERS-CoV and SARS-CoV-2 infection in vivo. Importantly, intranasally and intraperitoneally administered H84T-BanLec are comparably effective. Mechanistic assays show that H84T-BanLec targets virus entry. High-speed atomic force microscopy depicts real-time multimolecular associations of H84T-BanLec dimers with the SARS-CoV-2 spike trimer. Single-molecule force spectroscopy demonstrates binding of H84T-BanLec to multiple SARS-CoV-2 spike mannose sites with high affinity and that H84T-BanLec competes with SARS-CoV-2 spike for binding to cellular ACE2. Modeling experiments identify distinct high-mannose glycans in spike recognized by H84T-BanLec. The multiple H84T-BanLec binding sites on spike likely account for the drug compound's broad-spectrum antiviral activity and the lack of resistant mutants.


Subject(s)
COVID-19 , Middle East Respiratory Syndrome Coronavirus , Humans , SARS-CoV-2 , Lectins/pharmacology , Mannose/pharmacology , Angiotensin-Converting Enzyme 2 , Spike Glycoprotein, Coronavirus/pharmacology , Antiviral Agents/pharmacology
16.
J Biol Chem ; 298(11): 102511, 2022 11.
Article in English | MEDLINE | ID: covidwho-2031421

ABSTRACT

Revealing the mechanisms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry and cell-to-cell spread might provide insights for understanding the underlying mechanisms of viral pathogenesis, tropism, and virulence. The signaling pathways involved in SARS-CoV-2 entry and viral spike-mediated cell-to-cell fusion remain elusive. In the current study, we found that macropinocytosis inhibitors significantly suppressed SARS-CoV-2 infection at both the entry and viral spike-mediated cell-to-cell fusion steps. We demonstrated that SARS-CoV-2 entry required the small GTPase Rac1 and its effector kinase p21-activated kinase 1 by dominant-negative and RNAi assays in human embryonic kidney 293T-angiotensin-converting enzyme 2 cells and that the serine protease transmembrane serine protease 2 reversed the decrease in SARS-CoV-2 entry caused by the macropinocytosis inhibitors. Moreover, in the cell-to-cell fusion assay, we confirmed that macropinocytosis inhibitors significantly decreased viral spike-mediated cell-to-cell fusion. Overall, we provided evidence that SARS-CoV-2 utilizes a macropinocytosis pathway to enter target cells and to efficiently promote viral spike-mediated cell-to-cell fusion.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Spike Glycoprotein, Coronavirus/metabolism , Cell Fusion , Virus Internalization , Serine Proteases
17.
Emerg Microbes Infect ; 11(1): 2275-2287, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-2004930

ABSTRACT

SARS-CoV-2 B.1.1.529.1 (Omicron BA.1) emerged in November 2021 and quickly became the predominant circulating SARS-CoV-2 variant globally. Omicron BA.1 contains more than 30 mutations in the spike protein, which contribute to its altered virological features when compared to the ancestral SARS-CoV-2 or previous SARS-CoV-2 variants. Recent studies by us and others demonstrated that Omicron BA.1 is less dependent on transmembrane serine protease 2 (TMPRSS2), less efficient in spike cleavage, less fusogenic, and adopts an altered propensity to utilize the plasma membrane and endosomal pathways for virus entry. Ongoing studies suggest that these virological features of Omicron BA.1 are in part retained by the subsequent Omicron sublineages. However, the exact spike determinants that contribute to these altered features of Omicron remain incompletely understood. In this study, we investigated the spike determinants for the observed virological characteristics of Omicron. By screening for the individual changes on Omicron BA.1 and BA.2 spike, we identify that 69-70 deletion, E484A, and H655Y contribute to the reduced TMPRSS2 usage while 25-27 deletion, S375F, and T376A result in less efficient spike cleavage. Among the shared spike mutations of BA.1 and BA.2, S375F and H655Y reduce spike-mediated fusogenicity. Interestingly, the H655Y change consistently reduces serine protease usage while increases the use of endosomal proteases. In keeping with these findings, the H655Y substitution alone reduces plasma membrane entry and facilitates endosomal entry when compared to SARS-CoV-2 WT. Overall, our study identifies key changes in Omicron spike that contributes to our understanding on the virological determinant and pathogenicity of Omicron.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Mutation , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
18.
Emerg Microbes Infect ; 11(1): 2093-2101, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-1978182

ABSTRACT

The replication and pathogenicity of SARS-CoV-2 Omicron BA.2 are comparable to that of BA.1 in experimental animal models. However, BA.2 has rapidly emerged to overtake BA.1 to become the predominant circulating SARS-CoV-2 variant worldwide. Here, we compared the replication fitness of BA.1 and BA.2 in cell culture and in the Syrian hamster model of COVID-19. Using a reverse genetics approach, we found that the BA.1-specific spike mutation G496S compromises its replication fitness, which may contribute to BA.1 being outcompeted by BA.2 in the real world. Additionally, the BA.1-unique G496S substitution confers differentiated sensitivity to therapeutic monoclonal antibodies, which partially recapitulates the immunoevasive phenotype of BA.1 and BA.2. In summary, our study identified G496S as an important determinant during the evolutionary trajectory of SARS-CoV-2.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Antibodies, Monoclonal , Cricetinae , Humans , Mesocricetus , Mutation, Missense , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics
19.
Nature ; 609(7928): 785-792, 2022 09.
Article in English | MEDLINE | ID: covidwho-1972633

ABSTRACT

Highly pathogenic coronaviruses, including severe acute respiratory syndrome coronavirus 2 (refs. 1,2) (SARS-CoV-2), Middle East respiratory syndrome coronavirus3 (MERS-CoV) and SARS-CoV-1 (ref. 4), vary in their transmissibility and pathogenicity. However, infection by all three viruses results in substantial apoptosis in cell culture5-7 and in patient tissues8-10, suggesting a potential link between apoptosis and pathogenesis of coronaviruses. Here we show that caspase-6, a cysteine-aspartic protease of the apoptosis cascade, serves as an important host factor for efficient coronavirus replication. We demonstrate that caspase-6 cleaves coronavirus nucleocapsid proteins, generating fragments that serve as interferon antagonists, thus facilitating virus replication. Inhibition of caspase-6 substantially attenuates lung pathology and body weight loss in golden Syrian hamsters infected with SARS-CoV-2 and improves the survival of mice expressing human DPP4 that are infected with mouse-adapted MERS-CoV. Our study reveals how coronaviruses exploit a component of the host apoptosis cascade to facilitate virus replication.


Subject(s)
Aspartic Acid , Caspase 6 , Coronavirus Infections , Coronavirus , Cysteine , Host-Pathogen Interactions , Virus Replication , Animals , Apoptosis , Aspartic Acid/metabolism , Caspase 6/metabolism , Coronavirus/growth & development , Coronavirus/pathogenicity , Coronavirus Infections/enzymology , Coronavirus Infections/virology , Coronavirus Nucleocapsid Proteins/immunology , Coronavirus Nucleocapsid Proteins/metabolism , Cricetinae , Cysteine/metabolism , Dipeptidyl Peptidase 4/genetics , Dipeptidyl Peptidase 4/metabolism , Humans , Interferons/antagonists & inhibitors , Interferons/immunology , Lung/pathology , Mesocricetus , Mice , Middle East Respiratory Syndrome Coronavirus , Severe acute respiratory syndrome-related coronavirus , SARS-CoV-2 , Survival Rate , Weight Loss
20.
Int J Biol Sci ; 18(12): 4744-4755, 2022.
Article in English | MEDLINE | ID: covidwho-1954694

ABSTRACT

Viruses exploit the host lipid metabolism machinery to achieve efficient replication. We herein characterize the lipids profile reprogramming in vitro and in vivo using liquid chromatography-mass spectrometry-based untargeted lipidomics. The lipidome of SARS-CoV-2-infected Caco-2 cells was markedly different from that of mock-infected samples, with most of the changes involving downregulation of ceramides. In COVID-19 patients' plasma samples, a total of 54 lipids belonging to 12 lipid classes that were significantly perturbed compared to non-infected control subjects' plasma samples were identified. Among these 12 lipid classes, ether-linked phosphatidylcholines, ether-linked phosphatidylethanolamines, phosphatidylcholines, and ceramides were the four most perturbed. Pathway analysis revealed that the glycerophospholipid, sphingolipid, and ether lipid metabolisms pathway were the most significantly perturbed host pathways. Phosphatidic acid phosphatases (PAP) were involved in all three pathways and PAP-1 deficiency significantly suppressed SARS-CoV-2 replication. siRNA knockdown of LPIN2 and LPIN3 resulted in significant reduction of SARS-CoV-2 load. In summary, these findings characterized the host lipidomic changes upon SARS-CoV-2 infection and identified PAP-1 as a potential target for intervention for COVID-19.


Subject(s)
COVID-19 , SARS-CoV-2 , Caco-2 Cells , Ceramides , Ethers , Glycerophospholipids , Humans , Lipid Metabolism , Phosphatidate Phosphatase/genetics , Phosphatidate Phosphatase/metabolism , Phosphatidylcholines/metabolism , Phosphatidylethanolamines/metabolism
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