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Principal Investigator: Ralph S Baric
Organization: UNIV OF NORTH CAROLINA CHAPEL HILL
Fiscal Year: 2019
Award: $721,207
Funding agency: National Institute of Allergy and Infectious Diseases
DESCRIPTION (provided by applicant): Recently, a novel and highly virulent Middle Eastern Respiratory Syndrome Coronavirus (MERS-CoV) emerged, causing ~40% mortality rates. MERS-CoV replicates efficiently in humans, camels and bats, but not mouse cells demonstrating a broad yet rodent-restricted host range. Ominously, person-to-person transmission and subclinical infections endanger global populations and economies. Importantly, we have demonstrated that closely related bat coronaviruses (Bt CoV), like HKU4, uses the same bat and human receptor for entry as MERS- CoV, raising the specter of further zoonotic introductions of antigenically distinct coronaviruses into human populations. Consequently, we develop a multidisciplinary program that includes X- Ray crystallography, electron microscopy, protein biochemistry, molecular virology, reverse genetics and animal model development to address fundamental questions regulating key BtCoV HKU4 and MERS-CoV-host structure-function relationships in: i) receptor mediated binding, fusion and entry, ii) cross species transmission, and iii) in vivo pathogenesis. MERS-CoV and BtCoV HKU4 encode an envelope-anchored spike glycoprotein (S) that binds to its host receptor dipeptidyl peptidase 4 (DPP4) through its S1 subunit, initiating a cascade of host serine protease regulated conformation changes that elicit S2-mediated membrane fusion and entry. The major barrier for HKU4 mediated entry into human cells occurs at protease initiated membrane fusion, rather than at the receptor binding interface. Thus, our program identifies a checkpoint associated with bat CoV cross species transmission into other mammals, including humans. In addition to identifying key structural and biochemical interactions that regulate S and DPP4 receptor ortholog-guided binding protease regulated fusion and entry, we apply reverse genetics, structure-guided mutations, and experimental evolution to study HKU4 and MERS-CoV host adaptation and pathogenesis, using recently developed transgenic animal models. In Aim 1, we study the biochemistry and structure of MERS-CoV and HKU4 bound to various species receptor-binding domains (RBD). In Aim 2, we study S processing by bat and human entry proteases. In Aim 3, we study HKU4 and MERS-CoV pathogenesis using transgenic mice and experimental evolution. The overall goal is to build a comprehensive understanding of the molecular mechanisms guiding group 2c CoV receptor recognition, entry and pathogenesis. In parallel, we produce key deliverables that are crucial for developing effective antivirals and vaccines, thereby improving rapid response and the overall global health.
Terms: <Address><Animal Model><Animal Models and Related Studies><Animals><Antiviral Agents><Antiviral Drugs><Antivirals><Artificial Genes><Bats><Binding><Binding Proteins><Bioavailability><Biochemical><Biochemistry><Biologic Availability><Biological Availability><Biological Chemistry><Camels><Cell Body><Cell Function><Cell Process><Cell physiology><Cells><Cellular Function><Cellular Physiology><Cellular Process><Chiroptera><Comparative Study><Coronaviridae><Coronavirus><Coupled><Data><Dipeptidyl Aminopeptidases><Dipeptidyl Peptidases><Dipeptidylpeptide Hydrolases><Disease><Disease Outbreaks><Disease Outcome><Disorder><Electron Microscopy><Epidemic><Esteroproteases><Event><Evolution><General Viruses><Genetic><Genetic Alteration><Genetic Change><Genetic Models><Genetic Structures><Genetic defect><Glycoproteins><Goals><History><Human><In Vitro><Infection><KO mice><Knock-out Mice><Knockout Mice><Ligand Binding Protein><Ligand Binding Protein Gene><Mammalia><Mammals><Mediating><Membrane><Membrane Fusion><Mice><Mice Mammals><Middle East><Modern Man><Molecular><Molecular Configuration><Molecular Conformation><Molecular Interaction><Molecular Stereochemistry><Molecular Virology><Murine><Mus><Mutation><Null Mouse><Ortholog><Orthologous Gene><Outbreaks><Pathogenesis><Pathway interactions><Peptidases><Peptide Hydrolases><Persons><Physiologic Availability><Population><Protease Gene><Proteases><Protein Binding><Protein Biochemistry><Protein/Amino Acid Biochemistry><Proteinases><Proteolytic Clipping><Proteolytic Enzymes><Proteolytic Processing><Public Health><Reagent><Receptor Protein><Recording of previous events><Research><Rodent><Rodentia><Rodents Mammals><Role><Serine Endopeptidases><Serine Protease><Serine Protein Hydrolases><Serine Proteinases><Single Crystal Diffraction><Site><Species Specificity><Structure><Structure-Activity Relationship><Subcellular Process><Syndrome><Synthetic Genes><Transgenic Animals><Transgenic Mice><Transmission><Tropism><Vaccines><Variant><Variation><Viral><Viral Receptor><Virulence><Virulent><Virus><Virus Receptors><X Ray Crystallographies><X-Ray Crystallography><X-Ray Diffraction Crystallography><X-Ray/Neutron Crystallography><Xray Crystallography><Zoonoses><Zoonotic><Zoonotic Infection><animal model development><anti-viral agents><anti-viral drugs><anti-virals><base><bound protein><chemical structure function><conformation><conformational state><coronavirus receptor><design><designing><genome mutation><global health><human disease><human model><improved><in vivo><membrane structure><model of animal><model organism><mortality><mouse model><multidisciplinary><murine model><mutant><novel><pathway><prevent><preventing><programs><public health relevance><receptor><receptor binding><receptor bound><recombinant virus><respiratory><respiratory virus><response><reverse genetics><social role><structural biology><structure function relationship><therapeutic evaluation><therapeutic testing><tissue tropism><transmission process><trend><vaccine evaluation><vaccine screening><vaccine testing><virus host interaction>