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Principal Investigator: VINEET D MENACHERY
Organization: UNIVERSITY OF TEXAS MED BR GALVESTON
Fiscal Year: 2020
Award: $497,886
Funding agency: National Institute of Allergy and Infectious Diseases
Abstract
The coronavirus (CoV) spike protein is a key viral determinant responsible for receptor binding and
fusion/entry. The spike protein has also been predicted to be the major factor driving cross-species
transmission, allowing the emergence of epidemic strains like SARS- and MERS-CoV. In the first decade after
SARS-CoV emergence, changes to the epidemic spike that allowed binding to a new host receptor were
thought to underlie this zoonotic emergence. However, our work has shown that bat species already harbor
SARS-like CoVs with spike proteins capable of infecting human cells. These results argue that for a subset of
bat CoVs, receptor binding and infection of human cells is not the major barrier for emergence.
We found that despite equivalent replication in vitro, chimeric viruses containing bat CoV spikes have reduced
virulence in vivo. Mice infected with a chimeric SARS-CoV expressing the bat derived SHC014-CoV spike had
reduced weight loss and lethality compared to SARS-CoV controls. Importantly, this attenuation occurs despite
equivalent replication to SARS-CoV in the lung. The results indicate that virulence is dictated by more than
just the ability to infect host cells in vitro. Notably, we also found that the SHC014 spike chimera has reduced
infection of the large airways of the lung. These preliminary data shaped our central hypothesis that SARS-
CoV virulence is predicated on both host interactions with and viral motifs in the CoV spike protein.
Understanding the host and viral mechanisms that drive reduced airway infection may predict in vivo
pathogenesis and have critical implications for zoonotic emergence.
In this proposal, we explore the host factors and CoV spike changes that attenuate the zoonotic SHC014 spike
in vivo. In part one, we examine tropism changes finding that the zoonotic SHC014 spike has impaired upper
airway infection. We predict that this incompatibility relates to differences in host protease activity. We
subsequently define the specific host proteases that mediate this attenuation using both in vitro and in vivo
approaches. In part two, we use mouse-adaptation and structural analysis to predict spike changes
responsible for attenuation of the SHC014 spike. We subsequently generate mutant viruses and restore the
SHC014 spike or attenuate the SARS spike in vivo. Finally, we evaluate the mechanism of attenuation
focusing on spike interactions with host proteases. Together, the proposal identifies host proteases and spike
interactions that alter airway infection and dictate virulence following coronavirus infection. These findings
provide critical insights for understanding virulence as well as have important implications for emergence and
transmission of coronaviruses.
Terms: <Attenuated><Automobile Driving><Bats><Binding><Body Weight decreased><CRISPR><CRISPR/Cas system><Cell Body><Cells><Chimera><Chimera organism><Chiroptera><Clustered Regularly Interspaced Short Palindromic Repeats><CoV S protein><CoV emergence><CoV glycoprotein S><CoV spike glycoprotein><CoV spike protein><Coronaviridae><Coronaviridae Infections><Coronavirus><Coronavirus Infections><Coronavirus glycoprotein S><Coronavirus spike protein><Data><Disease><Disorder><Drug Therapy><Drug usage><Epidemic><Esteroproteases><Family><Genetic Alteration><Genetic Change><Genetic defect><Goals><Host Factor><Host Factor Protein><Human><Immune response><Immunological response><Impairment><In Vitro><Infection><Integration Host Factors><Lung><Lung Respiratory System><MERS corona virus><MERS coronavirus><MERS virus><MERS-CoV><Mediating><Mice><Mice Mammals><Middle East Respiratory Syndrome Corona Virus><Middle East Respiratory Syndrome Coronavirus><Middle East Respiratory Syndrome Virus><Middle East Respiratory Syndrome-CoV><Middle Eastern Respiratory Syndrome Corona virus><Middle Eastern Respiratory Syndrome Coronavirus><Middle Eastern Respiratory Syndrome Virus><Middle Eastern Respiratory Syndrome-CoV><Modeling><Modern Man><Molecular Interaction><Monitor><Murine><Mus><Mutation><Pathogenesis><Peptidases><Peptide Hydrolases><Pharmacotherapy><Protease Gene><Proteases><Proteinases><Proteins><Proteolytic Enzymes><Receptor Protein><SARS><SARS Virus><SARS corona virus><SARS coronavirus><SARS coronavirus disease><SARS-Associated Coronavirus><SARS-CoV><SARS-CoV disease><SARS-Related Coronavirus><Serine Endopeptidases><Serine Protease><Serine Protein Hydrolases><Serine Proteinases><Severe Acute Respiratory Syndrome><Severe Acute Respiratory Syndrome CoV disease><Severe Acute Respiratory Syndrome Virus><Severe Acute Respiratory Syndrome corona virus><Severe Acute Respiratory Syndrome coronavirus><Severe Acute Respiratory Syndrome coronavirus disease><Structural Models><Structure><System><Testing><Transmission><Tropism><Viral><Virulence><Virus><Weight Loss><Weight Reduction><Work><Zoonoses><Zoonotic><Zoonotic Infection><attenuation><base><body weight loss><corona virus><coronavirus S protein><coronavirus emergence><coronavirus receptor><coronavirus spike glycoprotein><cross-species spillover><cross-species transmission><driving><drug treatment><drug use><emergent CoV><emergent coronavirus><emerging CoV><emerging coronavirus><experiment><experimental research><experimental study><genome mutation><host jump><host response><host switching><immunoresponse><in vivo><insight><interspecies transmission><knockout gene><mutant><nCoV><new CoV><new coronavirus><novel><novel CoV><novel coronavirus><pulmonary><receptor><receptor binding><receptor bound><restoration><reverse genetics><severe acute respiratory syndrome-CoV><transmission across species><transmission between species><transmission process><transmitted across species><transmitted between species><transmitted cross-species><wt-loss>