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1.
Am J Physiol Regul Integr Comp Physiol ; 322(3): R161-R169, 2022 03 01.
Article in English | MEDLINE | ID: covidwho-1770007

ABSTRACT

Arginine vasopressin (AVP) is produced in the paraventricular (PVN) and supraoptic nuclei (SON). Peripheral AVP, which is secreted from the posterior pituitary, is produced in the magnocellular division of the PVN (mPVN) and SON. In addition, AVP is produced in the parvocellular division of the PVN (pPVN), where corticotrophin-releasing factor (CRF) is synthesized. These peptides synergistically modulate the hypothalamic-pituitary-adrenal (HPA) axis. Previous studies have revealed that the HPA axis was activated by hypovolemia. However, the detailed dynamics of AVP in the pPVN under hypovolemic state has not been elucidated. Here, we evaluated the effects of hypovolemia and hyperosmolality on the hypothalamus, using AVP-enhanced green fluorescent protein (eGFP) transgenic rats. Polyethylene glycol (PEG) or 3% hypertonic saline (HTN) was intraperitoneally administered to develop hypovolemia or hyperosmolality. AVP-eGFP intensity was robustly upregulated at 3 and 6 h after intraperitoneal administration of PEG or HTN in the mPVN. While in the pPVN, eGFP intensity was significantly increased at 6 h after intraperitoneal administration of PEG with significant induction of Fos-immunoreactive (-ir) neurons. Consistently, eGFP mRNA, AVP hnRNA, and CRF mRNA in the pPVN and plasma AVP and corticosterone were significantly increased at 6 h after intraperitoneal administration of PEG. The results suggest that AVP and CRF syntheses in the pPVN were activated by hypovolemia, resulting in the activation of the HPA axis.


Subject(s)
Arginine Vasopressin/genetics , Green Fluorescent Proteins/genetics , Hypothalamo-Hypophyseal System/metabolism , Hypovolemia/metabolism , Paraventricular Hypothalamic Nucleus/metabolism , Animals , Corticosterone/blood , Corticotropin-Releasing Hormone/genetics , Corticotropin-Releasing Hormone/metabolism , Disease Models, Animal , Genes, Reporter , Green Fluorescent Proteins/biosynthesis , Hypothalamo-Hypophyseal System/physiopathology , Hypovolemia/genetics , Hypovolemia/physiopathology , Injections, Intraperitoneal , Male , Paraventricular Hypothalamic Nucleus/physiopathology , Polyethylene Glycols/administration & dosage , Proto-Oncogene Proteins c-fos/metabolism , Rats, Transgenic , Rats, Wistar , Saline Solution, Hypertonic/administration & dosage , Supraoptic Nucleus/metabolism , Supraoptic Nucleus/physiopathology , Time Factors , Up-Regulation
2.
Biologicals ; 75: 12-15, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1616379

ABSTRACT

BACKGROUND: The successful development of messenger RNA vaccines for SARS-CoV-2 opened up venues for clinical nucleotide-based vaccinations. For development of DNA vaccines, we tested whether the EGF domain peptide of Developmentally regulated endothelial locus1 (E3 peptide) enhances uptake of extracellularly applied plasmid DNA. METHODS: DNA plasmid encoding lacZ or GFP was applied with a conditioned culture medium containing E3 peptide to cell lines in vitro or mouse soleus muscles in vivo, respectively. After 48 h incubation, gene expression was examined by ß-galactosidase (ß-gal) assay and fluorescent microscope, respectively. RESULTS: Application of E3 peptide-containing medium to cultured cell lines induced intense ß-gal activity in a dose-dependent manner. Intra-gastrocnemius injection of E3 peptide-containing medium to mouse soleus muscle succeeded in the induction of GFP fluorescence in many cells around the injection site. CONCLUSIONS: The administration of E3 peptide facilitates transmembrane uptake of extracellular DNA plasmid which induces sufficient extrinsic gene expression.


Subject(s)
DNA/genetics , Epidermal Growth Factor/chemistry , Gene Expression , Peptides , Plasmids/genetics , Plasmids/metabolism , Protein Domains , Animals , COVID-19 Vaccines , Cell Membrane/metabolism , DNA/metabolism , Genes, Reporter , Green Fluorescent Proteins/genetics , Mice , Muscle, Skeletal , Vaccines, DNA/genetics , Vaccines, DNA/metabolism
3.
J Virol ; 96(3): e0183721, 2022 02 09.
Article in English | MEDLINE | ID: covidwho-1546443

ABSTRACT

Research activities with infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are currently permitted only under biosafety level 3 (BSL3) containment. Here, we report the development of a single-cycle infectious SARS-CoV-2 virus replicon particle (VRP) system with a luciferase and green fluorescent protein (GFP) dual reporter that can be safely handled in BSL2 laboratories to study SARS-CoV-2 biology. The spike (S) gene of SARS-CoV-2 encodes the envelope glycoprotein, which is essential for mediating infection of new host cells. Through deletion and replacement of this essential S gene with a luciferase and GFP dual reporter, we have generated a conditional SARS-CoV-2 mutant (ΔS-VRP) that produces infectious particles only in cells expressing a viral envelope glycoprotein of choice. Interestingly, we observed more efficient production of infectious particles in cells expressing vesicular stomatitis virus (VSV) glycoprotein G [ΔS-VRP(G)] than in cells expressing other viral glycoproteins, including S. We confirmed that infection from ΔS-VRP(G) is limited to a single round and can be neutralized by anti-VSV serum. In our studies with ΔS-VRP(G), we observed robust expression of both luciferase and GFP reporters in various human and murine cell types, demonstrating that a broad variety of cells can support intracellular replication of SARS-CoV-2. In addition, treatment of ΔS-VRP(G)-infected cells with either of the anti-CoV drugs remdesivir (nucleoside analog) and GC376 (CoV 3CL protease inhibitor) resulted in a robust decrease in both luciferase and GFP expression in a drug dose- and cell-type-dependent manner. Taken together, our findings show that we have developed a single-cycle infectious SARS-CoV-2 VRP system that serves as a versatile platform to study SARS-CoV-2 intracellular biology and to perform high-throughput screening of antiviral drugs under BSL2 containment. IMPORTANCE Due to the highly contagious nature of SARS-CoV-2 and the lack of immunity in the human population, research on SARS-CoV-2 has been restricted to biosafety level 3 laboratories. This has greatly limited participation of the broader scientific community in SARS-CoV-2 research and thus has hindered the development of vaccines and antiviral drugs. By deleting the essential spike gene in the viral genome, we have developed a conditional mutant of SARS-CoV-2 with luciferase and fluorescent reporters, which can be safely used under biosafety level 2 conditions. Our single-cycle infectious SARS-CoV-2 virus replicon system can serve as a versatile platform to study SARS-CoV-2 intracellular biology and to perform high-throughput screening of antiviral drugs under BSL2 containment.


Subject(s)
Genetic Engineering , Recombination, Genetic , Replicon , SARS-CoV-2/genetics , COVID-19/virology , Cell Culture Techniques , Cell Line , Containment of Biohazards/standards , Genes, Reporter , Humans , Laboratories/standards , Viral Proteins/genetics , Virus Replication
4.
J Virol ; 96(3): e0156121, 2022 02 09.
Article in English | MEDLINE | ID: covidwho-1529876

ABSTRACT

Historically part of the coronavirus (CoV) family, torovirus (ToV) was recently classified in the new family Tobaniviridae. While reverse genetics systems have been established for various CoVs, none exist for ToVs. Here, we developed a reverse genetics system using an infectious full-length cDNA clone of bovine ToV (BToV) in a bacterial artificial chromosome (BAC). Recombinant BToV harboring genetic markers had the same phenotype as wild-type (wt) BToV. To generate two types of recombinant virus, the hemagglutinin-esterase (HE) gene was edited, as cell-adapted wtBToV generally loses full-length HE (HEf), resulting in soluble HE (HEs). First, recombinant viruses with HEf and hemagglutinin (HA)-tagged HEf or HEs genes were rescued. These exhibited no significant differences in their effect on virus growth in HRT18 cells, suggesting that HE is not essential for viral replication in these cells. Thereafter, we generated a recombinant virus (rEGFP) wherein HE was replaced by the enhanced green fluorescent protein (EGFP) gene. rEGFP expressed EGFP in infected cells but showed significantly lower levels of viral growth than wtBToV. Moreover, rEGFP readily deleted the EGFP gene after one passage. Interestingly, rEGFP variants with two mutations (C1442F and I3562T) in nonstructural proteins (NSPs) that emerged during passage exhibited improved EGFP expression, EGFP gene retention, and viral replication. An rEGFP into which both mutations were introduced displayed a phenotype similar to that of these variants, suggesting that the mutations contributed to EGFP gene acceptance. The current findings provide new insights into BToV, and reverse genetics will help advance the current understanding of this neglected pathogen. IMPORTANCE ToVs are diarrhea-causing pathogens detected in various species, including humans. Through the development of a BAC-based BToV, we introduced the first reverse genetics system for Tobaniviridae. Utilizing this system, recombinant BToVs with a full-length HE gene were generated. Remarkably, although clinical BToVs generally lose the HE gene after a few passages, some recombinant viruses generated in the current study retained the HE gene for up to 20 passages while accumulating mutations in NSPs, which suggested that these mutations may be involved in HE gene retention. The EGFP gene of recombinant viruses was unstable, but rEGFP into which two NSP mutations were introduced exhibited improved EGFP expression, gene retention, and viral replication. These data suggested the existence of an NSP-based acceptance or retention mechanism for exogenous RNA or HE genes. Recombinant BToVs and reverse genetics are powerful tools for understanding fundamental viral processes, pathogenesis, and BToV vaccine development.


Subject(s)
DNA, Complementary , Genome, Viral , Reverse Genetics , Torovirus/genetics , Animals , Cattle , Cattle Diseases/virology , Cell Line , Cells, Cultured , Chromosomes, Artificial, Bacterial , Cloning, Molecular , Genes, Reporter , Hemagglutinins, Viral/genetics , Hemagglutinins, Viral/metabolism , Mutation , Plasmids/genetics , Torovirus/isolation & purification , Torovirus Infections , Transfection
5.
Proc Natl Acad Sci U S A ; 118(45)2021 11 09.
Article in English | MEDLINE | ID: covidwho-1475573

ABSTRACT

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other pathogens with pandemic potential requires safe, protective, inexpensive, and easily accessible vaccines that can be developed and manufactured rapidly at a large scale. DNA vaccines can achieve these criteria, but induction of strong immune responses has often required bulky, expensive electroporation devices. Here, we report an ultra-low-cost (<1 USD), handheld (<50 g) electroporation system utilizing a microneedle electrode array ("ePatch") for DNA vaccination against SARS-CoV-2. The low cost and small size are achieved by combining a thumb-operated piezoelectric pulser derived from a common household stove lighter that emits microsecond, bipolar, oscillatory electric pulses and a microneedle electrode array that targets delivery of high electric field strength pulses to the skin's epidermis. Antibody responses against SARS-CoV-2 induced by this electroporation system in mice were strong and enabled at least 10-fold dose sparing compared to conventional intramuscular or intradermal injection of the DNA vaccine. Vaccination was well tolerated with mild, transient effects on the skin. This ePatch system is easily portable, without any battery or other power source supply, offering an attractive, inexpensive approach for rapid and accessible DNA vaccination to combat COVID-19, as well as other epidemics.


Subject(s)
COVID-19 Vaccines/administration & dosage , COVID-19/immunology , COVID-19/prevention & control , Electroporation/instrumentation , SARS-CoV-2 , Vaccines, DNA/administration & dosage , Animals , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , Costs and Cost Analysis , Electroporation/economics , Electroporation/methods , Equipment Design , Female , Genes, Reporter , Humans , Mice , Mice, Inbred BALB C , Microelectrodes , Needles , Pandemics/prevention & control , Proof of Concept Study , Rats , Rats, Wistar , Skin/immunology , Skin/metabolism , Transfection , Vaccination/economics , Vaccination/instrumentation , Vaccination/methods , Vaccines, DNA/genetics , Vaccines, DNA/immunology
6.
Viruses ; 13(10)2021 10 04.
Article in English | MEDLINE | ID: covidwho-1463827

ABSTRACT

Porcine deltacoronavirus (PDCoV), an emerging enteropathogenic coronavirus, causes diarrhoea in suckling piglets and has the potential for cross-species transmission. No effective PDCoV vaccines or antiviral drugs are currently available. Here, we successfully generated an infectious clone of PDCoV strain CHN-HN-2014 using a combination of bacterial artificial chromosome (BAC)-based reverse genetics system with a one-step homologous recombination. The recued virus (rCHN-HN-2014) possesses similar growth characteristics to the parental virus in vitro. Based on the established infectious clone and CRISPR/Cas9 technology, a PDCoV reporter virus expressing nanoluciferase (Nluc) was constructed by replacing the NS6 gene. Using two drugs, lycorine and resveratrol, we found that the Nluc reporter virus exhibited high sensibility and easy quantification to rapid antiviral screening. We further used the Nluc reporter virus to test the susceptibility of different cell lines to PDCoV and found that cell lines derived from various host species, including human, swine, cattle and monkey enables PDCoV replication, broadening our understanding of the PDCoV cell tropism range. Taken together, our reporter viruses are available to high throughput screening for antiviral drugs and uncover the infectivity of PDCoV in various cells, which will accelerate our understanding of PDCoV.


Subject(s)
Coronavirus Infections/veterinary , Deltacoronavirus/genetics , Deltacoronavirus/metabolism , Genes, Reporter/genetics , Luciferases/genetics , A549 Cells , Animals , Cell Line , Chlorocebus aethiops , Chromosomes, Artificial, Bacterial/genetics , Coronavirus Infections/pathology , Deltacoronavirus/growth & development , Dogs , Genome, Viral/genetics , Humans , Luciferases/biosynthesis , Madin Darby Canine Kidney Cells , Nanostructures , Swine , Swine Diseases/virology , Vero Cells , Virus Replication/genetics
7.
Proc Natl Acad Sci U S A ; 118(41)2021 10 12.
Article in English | MEDLINE | ID: covidwho-1437721

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the current COVID-19 pandemic, is one of the biggest threats to public health. However, the dynamic of SARS-CoV-2 infection remains poorly understood. Replication-competent recombinant viruses expressing reporter genes provide valuable tools to investigate viral infection. Low levels of reporter gene expressed from previous reporter-expressing recombinant (r)SARS-CoV-2 in the locus of the open reading frame (ORF)7a protein have jeopardized their use to monitor the dynamic of SARS-CoV-2 infection in vitro or in vivo. Here, we report an alternative strategy where reporter genes were placed upstream of the highly expressed viral nucleocapsid (N) gene followed by a porcine tescherovirus (PTV-1) 2A proteolytic cleavage site. The higher levels of reporter expression using this strategy resulted in efficient visualization of rSARS-CoV-2 in infected cultured cells and excised lungs or whole organism of infected K18 human angiotensin converting enzyme 2 (hACE2) transgenic mice. Importantly, real-time viral infection was readily tracked using a noninvasive in vivo imaging system and allowed us to rapidly identify antibodies which are able to neutralize SARS-CoV-2 infection in vivo. Notably, these reporter-expressing rSARS-CoV-2, in which a viral gene was not deleted, not only retained wild-type (WT) virus-like pathogenicity in vivo but also exhibited high stability in vitro and in vivo, supporting their use to investigate viral infection, dissemination, pathogenesis, and therapeutic interventions for the treatment of SARS-CoV-2 in vivo.


Subject(s)
COVID-19 , Gene Expression Regulation, Viral , Genes, Reporter , SARS-CoV-2 , Viral Proteins , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/genetics , COVID-19/metabolism , Chlorocebus aethiops , Coronavirus Nucleocapsid Proteins/biosynthesis , Coronavirus Nucleocapsid Proteins/genetics , Female , Humans , Mice , Mice, Transgenic , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Teschovirus/genetics , Vero Cells , Viral Proteins/biosynthesis , Viral Proteins/genetics
8.
Cell ; 184(20): 5247-5260.e19, 2021 09 30.
Article in English | MEDLINE | ID: covidwho-1415259

ABSTRACT

3' untranslated region (3'UTR) variants are strongly associated with human traits and diseases, yet few have been causally identified. We developed the massively parallel reporter assay for 3'UTRs (MPRAu) to sensitively assay 12,173 3'UTR variants. We applied MPRAu to six human cell lines, focusing on genetic variants associated with genome-wide association studies (GWAS) and human evolutionary adaptation. MPRAu expands our understanding of 3'UTR function, suggesting that simple sequences predominately explain 3'UTR regulatory activity. We adapt MPRAu to uncover diverse molecular mechanisms at base pair resolution, including an adenylate-uridylate (AU)-rich element of LEPR linked to potential metabolic evolutionary adaptations in East Asians. We nominate hundreds of 3'UTR causal variants with genetically fine-mapped phenotype associations. Using endogenous allelic replacements, we characterize one variant that disrupts a miRNA site regulating the viral defense gene TRIM14 and one that alters PILRB abundance, nominating a causal variant underlying transcriptional changes in age-related macular degeneration.


Subject(s)
3' Untranslated Regions/genetics , Biological Evolution , Disease/genetics , Genome-Wide Association Study , Algorithms , Alleles , Gene Expression Regulation , Genes, Reporter , Genetic Variation , Humans , Phenotype , Polymorphism, Single Nucleotide/genetics , Polyribosomes/metabolism , Quantitative Trait Loci/genetics , RNA/genetics
9.
J Virol ; 95(22): e0112621, 2021 10 27.
Article in English | MEDLINE | ID: covidwho-1398575

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged at the end of 2019 and has been responsible for the still ongoing coronavirus disease 2019 (COVID-19) pandemic. Prophylactic vaccines have been authorized by the U.S. Food and Drug Administration (FDA) for the prevention of COVID-19. Identification of SARS-CoV-2-neutralizing antibodies (NAbs) is important to assess vaccine protection efficacy, including their ability to protect against emerging SARS-CoV-2 variants of concern (VoC). Here, we report the generation and use of a recombinant (r)SARS-CoV-2 USA/WA1/2020 (WA-1) strain expressing Venus and an rSARS-CoV-2 strain expressing mCherry and containing mutations K417N, E484K, and N501Y found in the receptor binding domain (RBD) of the spike (S) glycoprotein of the South African (SA) B.1.351 (beta [ß]) VoC in bifluorescent-based assays to rapidly and accurately identify human monoclonal antibodies (hMAbs) able to neutralize both viral infections in vitro and in vivo. Importantly, our bifluorescent-based system accurately recapitulated findings observed using individual viruses. Moreover, fluorescent-expressing rSARS-CoV-2 strain and the parental wild-type (WT) rSARS-CoV-2 WA-1 strain had similar viral fitness in vitro, as well as similar virulence and pathogenicity in vivo in the K18 human angiotensin-converting enzyme 2 (hACE2) transgenic mouse model of SARS-CoV-2 infection. We demonstrate that these new fluorescent-expressing rSARS-CoV-2 can be used in vitro and in vivo to easily identify hMAbs that simultaneously neutralize different SARS-CoV-2 strains, including VoC, for the rapid assessment of vaccine efficacy or the identification of prophylactic and/or therapeutic broadly NAbs for the treatment of SARS-CoV-2 infection. IMPORTANCE SARS-CoV-2 is responsible of the COVID-19 pandemic that has warped daily routines and socioeconomics. There is still an urgent need for prophylactics and therapeutics to treat SARS-CoV-2 infections. In this study, we demonstrate the feasibility of using bifluorescent-based assays for the rapid identification of hMAbs with neutralizing activity against SARS-CoV-2, including VoC in vitro and in vivo. Importantly, results obtained with these bifluorescent-based assays recapitulate those observed with individual viruses, demonstrating their feasibility to rapidly advance our understanding of vaccine efficacy and to identify broadly protective human NAbs for the therapeutic treatment of SARS-CoV-2.


Subject(s)
Antibodies, Neutralizing/immunology , Neutralization Tests/methods , SARS-CoV-2/immunology , Animals , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/therapeutic use , Antibodies, Neutralizing/therapeutic use , Broadly Neutralizing Antibodies/immunology , Broadly Neutralizing Antibodies/therapeutic use , COVID-19/therapy , COVID-19/virology , Genes, Reporter , Humans , Luminescent Proteins/genetics , Luminescent Proteins/metabolism , Lung/drug effects , Lung/virology , Mice , Mutation , Recombinant Proteins/genetics , Recombinant Proteins/immunology , Recombinant Proteins/metabolism , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism , Viral Load/drug effects , Virus Replication/drug effects
10.
PLoS Pathog ; 17(9): e1009898, 2021 09.
Article in English | MEDLINE | ID: covidwho-1394564

ABSTRACT

The respiratory disease COVID-19 is caused by the coronavirus SARS-CoV-2. Here we report the discovery of ethacridine as a potent drug against SARS-CoV-2 (EC50 ~ 0.08 µM). Ethacridine was identified via high-throughput screening of an FDA-approved drug library in living cells using a fluorescence assay. Plaque assays, RT-PCR and immunofluorescence imaging at various stages of viral infection demonstrate that the main mode of action of ethacridine is through inactivation of viral particles, preventing their binding to the host cells. Consistently, ethacridine is effective in various cell types, including primary human nasal epithelial cells that are cultured in an air-liquid interface. Taken together, our work identifies a promising, potent, and new use of the old drug via a distinct mode of action for inhibiting SARS-CoV-2.


Subject(s)
Antiviral Agents/pharmacology , Ethacridine/pharmacology , Protease Inhibitors/pharmacology , Virus Activation/drug effects , Animals , Cell Line , Chlorocebus aethiops , Coronavirus 3C Proteases/antagonists & inhibitors , Genes, Reporter , Green Fluorescent Proteins/genetics , Humans , Vero Cells , Virion/drug effects , Virus Replication/drug effects
11.
Cells ; 10(9)2021 08 31.
Article in English | MEDLINE | ID: covidwho-1390542

ABSTRACT

The rising prevalence of diabetes is threatening global health. It is known not only for the occurrence of severe complications but also for the SARS-Cov-2 pandemic, which shows that it exacerbates susceptibility to infections. Current therapies focus on artificially maintaining insulin homeostasis, and a durable cure has not yet been achieved. We demonstrate that our set of small molecule inhibitors of DYRK1A kinase potently promotes ß-cell proliferation, enhances long-term insulin secretion, and balances glucagon level in the organoid model of the human islets. Comparable activity is seen in INS-1E and MIN6 cells, in isolated mice islets, and human iPSC-derived ß-cells. Our compounds exert a significantly more pronounced effect compared to harmine, the best-documented molecule enhancing ß-cell proliferation. Using a body-like environment of the organoid, we provide a proof-of-concept that small-molecule-induced human ß-cell proliferation via DYRK1A inhibition is achievable, which lends a considerable promise for regenerative medicine in T1DM and T2DM treatment.


Subject(s)
Homeostasis , Insulin-Secreting Cells/cytology , Insulin-Secreting Cells/enzymology , Insulin/metabolism , Protein Kinase Inhibitors/pharmacology , Protein-Tyrosine Kinases/antagonists & inhibitors , Animals , Cell Line , Cell Proliferation/drug effects , Cell Survival/drug effects , Genes, Reporter , Harmine/pharmacology , Homeostasis/drug effects , Humans , Induced Pluripotent Stem Cells/drug effects , Induced Pluripotent Stem Cells/metabolism , Insulin-Secreting Cells/drug effects , Kinetics , Male , Mice , Models, Biological , NFATC Transcription Factors/metabolism , Organoids/drug effects , Organoids/metabolism , Protein Kinase Inhibitors/chemistry , Protein-Tyrosine Kinases/metabolism , Rats , Transforming Growth Factor beta/antagonists & inhibitors , Transforming Growth Factor beta/metabolism
12.
Angew Chem Int Ed Engl ; 60(24): 13280-13286, 2021 06 07.
Article in English | MEDLINE | ID: covidwho-1384109

ABSTRACT

Eukaryotic mRNAs are emerging modalities for protein replacement therapy and vaccination. Their 5' cap is important for mRNA translation and immune response and can be naturally methylated at different positions by S-adenosyl-l-methionine (AdoMet)-dependent methyltransferases (MTases). We report on the cosubstrate scope of the MTase CAPAM responsible for methylation at the N6 -position of adenosine start nucleotides using synthetic AdoMet analogs. The chemo-enzymatic propargylation enabled production of site-specifically modified reporter-mRNAs. These cap-propargylated mRNAs were efficiently translated and showed ≈3-fold increased immune response in human cells. The same effects were observed when the receptor binding domain (RBD) of SARS-CoV-2-a currently tested epitope for mRNA vaccination-was used. Site-specific chemo-enzymatic modification of eukaryotic mRNA may thus be a suitable strategy to modulate translation and immune response of mRNAs for future therapeutic applications.


Subject(s)
RNA Caps/immunology , RNA, Messenger/immunology , COVID-19/pathology , COVID-19/virology , Chromatography, High Pressure Liquid , Genes, Reporter , HEK293 Cells , Humans , Mass Spectrometry , Methylation , Methyltransferases/metabolism , Protein Biosynthesis , Protein Domains/genetics , Protein Domains/immunology , RNA Caps/analysis , RNA Caps/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , S-Adenosylmethionine/chemistry , S-Adenosylmethionine/immunology , S-Adenosylmethionine/metabolism , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
13.
Commun Biol ; 4(1): 557, 2021 05 11.
Article in English | MEDLINE | ID: covidwho-1387494

ABSTRACT

Dengue virus (DENV) is spread from human to human through the bite of the female Aedes aegypti mosquito and leads to about 100 million clinical infections yearly. Treatment options and vaccine availability for DENV are limited. Defective interfering particles (DIPs) are considered a promising antiviral approach but infectious virus contamination has limited their development. Here, a DENV-derived DIP production cell line was developed that continuously produced DENV-free DIPs. The DIPs contained and could deliver to cells a DENV serotype 2 subgenomic defective-interfering RNA, which was originally discovered in DENV infected patients. The DIPs released into cell culture supernatant were purified and could potently inhibit replication of all DENV serotypes in cells. Antiviral therapeutics are limited for many viral infection. The DIP system described could be re-purposed to make antiviral DIPs for many other RNA viruses such as SARS-CoV-2, yellow fever, West Nile and Zika viruses.


Subject(s)
Defective Viruses , Dengue Vaccines/therapeutic use , Dengue Virus/growth & development , Dengue/prevention & control , Virus Replication , Animals , Cell Line, Tumor , Chlorocebus aethiops , Defective Viruses/genetics , Defective Viruses/metabolism , Dengue/virology , Dengue Virus/genetics , Dengue Virus/metabolism , Genes, Reporter , HEK293 Cells , Host-Pathogen Interactions , Humans , Luminescent Proteins/biosynthesis , Luminescent Proteins/genetics , RNA, Viral/biosynthesis , RNA, Viral/genetics , Vero Cells , Viral Load
14.
Nat Commun ; 12(1): 4586, 2021 07 28.
Article in English | MEDLINE | ID: covidwho-1387355

ABSTRACT

Heterogeneous immunoassays such as ELISA have become indispensable in modern bioanalysis, yet translation into point-of-care assays is hindered by their dependence on external calibration and multiple washing and incubation steps. Here, we introduce RAPPID (Ratiometric Plug-and-Play Immunodiagnostics), a mix-and-measure homogeneous immunoassay platform that combines highly specific antibody-based detection with a ratiometric bioluminescent readout. The concept entails analyte-induced complementation of split NanoLuc luciferase fragments, photoconjugated to an antibody sandwich pair via protein G adapters. Introduction of a calibrator luciferase provides a robust ratiometric signal that allows direct in-sample calibration and quantitative measurements in complex media such as blood plasma. We developed RAPPID sensors that allow low-picomolar detection of several protein biomarkers, anti-drug antibodies, therapeutic antibodies, and both SARS-CoV-2 spike protein and anti-SARS-CoV-2 antibodies. With its easy-to-implement standardized workflow, RAPPID provides an attractive, fast, and low-cost alternative to traditional immunoassays, in an academic setting, in clinical laboratories, and for point-of-care applications.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Immunoassay/standards , Luminescent Measurements/standards , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/blood , COVID-19/immunology , COVID-19/virology , COVID-19 Serological Testing/instrumentation , Calibration , GTP-Binding Proteins/chemistry , Genes, Reporter , Humans , Immunoconjugates/chemistry , Limit of Detection , Luciferases/genetics , Luciferases/metabolism , Point-of-Care Testing , SARS-CoV-2/genetics
15.
Viruses ; 12(6)2020 05 30.
Article in English | MEDLINE | ID: covidwho-1389514

ABSTRACT

Single-stranded positive RNA ((+) ssRNA) viruses include several important human pathogens. Some members are responsible for large outbreaks, such as Zika virus, West Nile virus, SARS-CoV, and SARS-CoV-2, while others are endemic, causing an enormous global health burden. Since vaccines or specific treatments are not available for most viral infections, the discovery of direct-acting antivirals (DAA) is an urgent need. Still, the low-throughput nature of and biosafety concerns related to traditional antiviral assays hinders the discovery of new inhibitors. With the advances of reverse genetics, reporter replicon systems have become an alternative tool for the screening of DAAs. Herein, we review decades of the use of (+) ssRNA viruses replicon systems for the discovery of antiviral agents. We summarize different strategies used to develop those systems, as well as highlight some of the most promising inhibitors identified by the method. Despite the genetic alterations introduced, reporter replicons have been shown to be reliable systems for screening and identification of viral replication inhibitors and, therefore, an important tool for the discovery of new DAAs.


Subject(s)
Antiviral Agents/pharmacology , Drug Discovery/methods , Genes, Reporter/physiology , RNA Viruses/drug effects , Replicon/physiology , Animals , Antiviral Agents/chemistry , Cell Line , Chlorocebus aethiops , Cricetinae , Humans , RNA Viruses/genetics , Transfection , Vero Cells
16.
Viruses ; 13(8)2021 07 28.
Article in English | MEDLINE | ID: covidwho-1376988

ABSTRACT

The human adenovirus phylogenetic tree is split across seven species (A-G). Species D adenoviruses offer potential advantages for gene therapy applications, with low rates of pre-existing immunity detected across screened populations. However, many aspects of the basic virology of species D-such as their cellular tropism, receptor usage, and in vivo biodistribution profile-remain unknown. Here, we have characterized human adenovirus type 49 (HAdV-D49)-a relatively understudied species D member. We report that HAdV-D49 does not appear to use a single pathway to gain cell entry, but appears able to interact with various surface molecules for entry. As such, HAdV-D49 can transduce a broad range of cell types in vitro, with variable engagement of blood coagulation FX. Interestingly, when comparing in vivo biodistribution to adenovirus type 5, HAdV-D49 vectors show reduced liver targeting, whilst maintaining transduction of lung and spleen. Overall, this presents HAdV-D49 as a robust viral vector platform for ex vivo manipulation of human cells, and for in vivo applications where the therapeutic goal is to target the lung or gain access to immune cells in the spleen, whilst avoiding liver interactions, such as intravascular vaccine applications.


Subject(s)
Adenoviruses, Human/genetics , Genetic Therapy/methods , Genetic Vectors/genetics , Adenoviruses, Human/classification , Adenoviruses, Human/metabolism , Animals , Cell Line , Genes, Reporter , Genetic Therapy/instrumentation , Genetic Vectors/metabolism , Humans , Liver/virology , Lung/virology , Mice , Phylogeny , Spleen/virology , Transduction, Genetic
17.
Bioengineered ; 12(1): 4407-4419, 2021 12.
Article in English | MEDLINE | ID: covidwho-1373615

ABSTRACT

Widespread infection due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) has led to a global pandemic. Currently, various approaches are being taken up to develop vaccines and therapeutics to treat SARS-CoV2 infection. Consequently, the S protein has become an important target protein for developing vaccines and therapeutics against SARS-CoV2. However, the highly infective nature of SARS-CoV2 restricts experimentation with the virus to highly secure BSL3 facilities. The availability of fusion-enabled, nonreplicating, and nonbiohazardous mimics of SARS-CoV2 virus fusion, containing the viral S or S and M protein in their native conformation on mammalian cells, can serve as a useful substitute for studying viral fusion for testing various inhibitors of viral fusion. This would avoid the use of the BSL3 facility for fusion studies required to develop therapeutics. In the present study, we have developed SARS-CoV2 virus fusion mimics (SCFMs) using mammalian cells transfected with constructs coding for S or S and M protein. The fusogenic property of the mimic(s) and their interaction with the functional human ACE2 receptors was confirmed experimentally. We have also shown that such mimics can easily be used in an inhibition assay. These mimic(s) can be easily prepared on a large scale, and such SCFMs can serve as an invaluable resource for viral fusion inhibition assays and in vitro screening of antiviral agents, which can be shared/handled between labs/facilities without worrying about any biohazard while working under routine laboratory conditions, avoiding the use of BSL3 laboratory.Abbreviations :SCFM: SARS-CoV2 Virus Fusion Mimic; ACE2: Angiotensin-Converting Enzyme 2; hACE2: Human Angiotensin-Converting enzyme 2; MEF: Mouse Embryonic Fibroblasts; HBSS: Hanks Balanced Salt Solution; FBS: Fetal Bovine Serum.


Subject(s)
Antibodies, Neutralizing/pharmacology , Containment of Biohazards/methods , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Viral Matrix Proteins/antagonists & inhibitors , Virus Internalization/drug effects , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , Chlorocebus aethiops , Embryo, Mammalian , Fibroblasts/drug effects , Fibroblasts/virology , Gene Expression , Genes, Reporter , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , HEK293 Cells , Humans , Luminescent Proteins/genetics , Luminescent Proteins/metabolism , MCF-7 Cells , Mice , Molecular Mimicry , Plasmids/chemistry , Plasmids/metabolism , Primary Cell Culture , Protein Binding , Receptors, Virus/genetics , Receptors, Virus/metabolism , SARS-CoV-2/drug effects , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Transfection , Vero Cells , Viral Matrix Proteins/genetics , Viral Matrix Proteins/metabolism
18.
Int J Mol Sci ; 22(13)2021 Jun 28.
Article in English | MEDLINE | ID: covidwho-1288900

ABSTRACT

A group of clinically approved cancer therapeutic tyrosine kinase inhibitors was screened to test their effects on the expression of angiotensin-converting enzyme 2 (ACE2), the cell surface receptor for SARS-CoV-2. Here, we show that the receptor tyrosine kinase inhibitor imatinib (also known as STI571, Gleevec) can inhibit the expression of the endogenous ACE2 gene at both the transcript and protein levels. Treatment with imatinib resulted in inhibition of cell entry of the viral pseudoparticles (Vpps) in cell culture. In FVB mice orally fed imatinib, tissue expression of ACE2 was reduced, specifically in the lungs and renal tubules, but not in the parenchyma of other organs such as the heart and intestine. Our finding suggests that receptor tyrosine kinases play a role in COVID-19 infection and can be therapeutic targets with combined treatments of the best conventional care of COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Down-Regulation/drug effects , Imatinib Mesylate/pharmacology , SARS-CoV-2/physiology , Virus Internalization/drug effects , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/genetics , Animals , COVID-19/pathology , COVID-19/virology , Cell Line , Cell Survival/drug effects , Chlorocebus aethiops , Female , Genes, Reporter , Humans , Mice , Promoter Regions, Genetic , SARS-CoV-2/isolation & purification
19.
J Virol Methods ; 295: 114221, 2021 09.
Article in English | MEDLINE | ID: covidwho-1284316

ABSTRACT

SARS-CoV-2 is the culprit causing Coronavirus Disease 2019 (COVID-19). For the study of SARS-CoV-2 infection in a BSL-2 laboratory, a SARS-CoV-2 pseudovirus particle (SARS2pp) production and infection system was constructed by using a lentiviral vector bearing dual-reporter genes eGFP and firefly luciferase (Luc2) for easy observation and analysis. Comparison of SARS2pp different production conditions revealed that the pseudovirus titer could be greatly improved by: 1) removing the last 19 amino acids of the spike protein and replacing the signal peptide with the mouse Igk signal sequence; 2) expressing the spike protein using CMV promoter other than CAG (a hybrid promoter consisting of a CMV enhancer, beta-actin promoter, splice donor, and a beta-globin splice acceptor); 3) screening better optimized spike protein sequences for SARS2pp production; and 4) adding 1 % BSA in the SARS2pp production medium. For infection, this SARS2pp system showed a good linear relationship between MOI 2-0.0002 and then was successfully used to evaluate SARS-CoV-2 infection inhibitors including recombinant human ACE2 proteins and SARS-CoV-2 neutralizing antibodies. The kidney, liver and small intestine-derived cell lines were also found to show different susceptibility to SARSpp and SARS2pp. Given its robustness and good performance, it is believed that this pseudovirus particle production and infection system will greatly promote future research for SARS-CoV-2 entry mechanisms and inhibitors and can be easily applied to study new emerging SARS-CoV-2 variants.


Subject(s)
Neutralization Tests/methods , SARS-CoV-2/physiology , Virus Internalization , Angiotensin-Converting Enzyme 2/pharmacology , Animals , Antibodies, Neutralizing/pharmacology , Antiviral Agents/pharmacology , Cell Line , Genes, Reporter , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Humans , Lentivirus/genetics , Luciferases, Firefly/genetics , Luciferases, Firefly/metabolism , Recombinant Proteins/pharmacology , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Virion , Virus Internalization/drug effects
20.
Int J Mol Sci ; 22(12)2021 Jun 18.
Article in English | MEDLINE | ID: covidwho-1273462

ABSTRACT

The COVID-19 pandemic caused by SARS-CoV-2 coronavirus deeply affected the world community. It gave a strong impetus to the development of not only approaches to diagnostics and therapy, but also fundamental research of the molecular biology of this virus. Fluorescence microscopy is a powerful technology enabling detailed investigation of virus-cell interactions in fixed and live samples with high specificity. While spatial resolution of conventional fluorescence microscopy is not sufficient to resolve all virus-related structures, super-resolution fluorescence microscopy can solve this problem. In this paper, we review the use of fluorescence microscopy to study SARS-CoV-2 and related viruses. The prospects for the application of the recently developed advanced methods of fluorescence labeling and microscopy-which in our opinion can provide important information about the molecular biology of SARS-CoV-2-are discussed.


Subject(s)
Microscopy, Fluorescence , SARS-CoV-2/physiology , COVID-19/pathology , COVID-19/virology , Endocytosis , Fluorescent Dyes/chemistry , Genes, Reporter , Humans , RNA, Viral/chemistry , RNA, Viral/metabolism , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Viral Envelope Proteins/chemistry , Viral Envelope Proteins/metabolism , Virus Internalization
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