Biology subjects

Yount, B. L.

Publications and source records attributed to Yount, B. L..

6 recordsLinked to original sources

bioRxiv2025

A neutralizing human antibody induces movement of the HCoV-229E receptor binding domain

HCoV-229E is an endemic Alphacoronavirus that typically causes common cold-like disease in most healthy adults, but can also cause severe respiratory disease in the very young and the elderly. Although the virus was discovered over sixty years ago and undergoes continuous antigenic drift, remarkably little is known about the humoral immune response to HCoV-229E infection. Here we report the isolation of two receptor binding domain-targeting neutralizing human antibodies raised in response to natural HCoV-229E infection. One of these, DH1533, potently neutralizes HCoV-229E, binds to spike with sub-nanomolar affinity and prevents the association between the RBD and the host cell receptor aminopeptidase N. Structural characterization of this antibody bound to HCoV-229E spike delineated a neutralization-sensitive epitope on the RBD and revealed that DH1533 induces conformational flexibility in neighboring RBDs, reminiscent of the "up-and-down" kinetics observed in the related Betacoronavirus spikes. These findings provide insight into the humoral immune response to HCoV-229E infection and will serve as a guide for the design of future therapeutic interventions.

immunology↗

bioRxiv2022

Host kinase CSNK2 is a target for inhibition of pathogenic β-coronaviruses including SARS-CoV-2

Inhibition of the protein kinase CSNK2 with any of 30 specific and selective inhibitors representing different chemotypes, blocked replication of pathogenic human and murine {beta}-coronaviruses. The potency of in-cell CSNK2A target engagement across the set of inhibitors correlated with antiviral activity and genetic knockdown confirmed the essential role of the CSNK2 holoenzyme in {beta}-coronavirus replication. Spike protein uptake was blocked by CSNK2A inhibition, indicating that antiviral activity was due in part to a suppression of viral entry. CSNK2A inhibition may be a viable target for development of new broad spectrum anti-{beta}-coronavirus drugs. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=72 SRC="FIGDIR/small/474779v3_ufig1.gif" ALT="Figure 1"> View larger version (19K): org.highwire.dtl.DTLVardef@5d2799org.highwire.dtl.DTLVardef@1d2de35org.highwire.dtl.DTLVardef@fa852eorg.highwire.dtl.DTLVardef@13da300_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2021

A global map of the Zika virus phosphoproteome reveals host-driven regulation of viral budding

Flaviviruses are enveloped, positive-strand RNA viruses that cause millions of infections in the human population annually. Although Zika virus (ZIKV) had been detected in humans as early as the 1950s, its reemergence in South America in 2015 resulted in a global health crisis. While flaviviruses encode 10 proteins that can be post-translationally modified by host enzymes, little is known regarding post-translational modifications (PTMs) of the flavivirus proteome. We used mass spectrometry to comprehensively identify host-driven PTMs on the ZIKV proteome. This approach allowed us to identify 43 PTMs across 8 ZIKV proteins, including several that are highly conserved within the Flavivirus genus. Notably, we found two phosphosites on the ZIKV envelope protein that are functionally important for viral propagation. Both appear to regulate viral budding, while one also impacts ZIKV cytopathogenicity. Additionally, we discovered host kinases that interact with ZIKV proteins and determined that Bosutinib--an FDA-approved tyrosine kinase inhibitor that targets some of these host kinases--impairs ZIKV growth, in part by blocking phosphorylation of a tyrosine residue on the envelope protein. Thus, we have defined a high-resolution map of host-driven PTMs on ZIKV proteins as well as cellular interacting kinases, uncovered novel mechanisms of host driven-regulation of ZIKV budding and cytopathogenicity, and identified an FDA-approved inhibitor of ZIKV growth.

microbiology↗

bioRxiv2020

A mouse-adapted SARS-CoV-2 model for the evaluation of COVID-19 medical countermeasures

Coronaviruses are prone to emergence into new host species most recently evidenced by SARS-CoV-2, the causative agent of the COVID-19 pandemic. Small animal models that recapitulate SARS-CoV-2 disease are desperately needed to rapidly evaluate medical countermeasures (MCMs). SARS-CoV-2 cannot infect wildtype laboratory mice due to inefficient interactions between the viral spike (S) protein and the murine ortholog of the human receptor, ACE2. We used reverse genetics to remodel the S and mACE2 binding interface resulting in a recombinant virus (SARS-CoV-2 MA) that could utilize mACE2 for entry. SARS-CoV-2 MA replicated in both the upper and lower airways of both young adult and aged BALB/c mice. Importantly, disease was more severe in aged mice, and showed more clinically relevant phenotypes than those seen in hACE2 transgenic mice. We then demonstrated the utility of this model through vaccine challenge studies in immune competent mice with native expression of mACE2. Lastly, we show that clinical candidate interferon (IFN) lambda-1a can potently inhibit SARS-CoV-2 replication in primary human airway epithelial cells in vitro, and both prophylactic and therapeutic administration diminished replication in mice. Our mouse-adapted SARS-CoV-2 model demonstrates age-related disease pathogenesis and supports the clinical use of IFN lambda-1a treatment in human COVID-19 infections.

microbiology↗

bioRxiv2020

Remdesivir potently inhibits SARS-CoV-2 in human lung cells and chimeric SARS-CoV expressing the SARS-CoV-2 RNA polymerase in mice.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in 2019 as the causative agent of the novel pandemic viral disease COVID-19. With no approved therapies, this pandemic illustrates the urgent need for safe, broad-spectrum antiviral countermeasures against SARS-CoV-2 and future emerging CoVs. We report that remdesivir (RDV), a monophosphoramidate prodrug of an adenosine analog, potently inhibits SARS-CoV-2 replication in human lung cells and primary human airway epithelial cultures (EC50 = 0.01 M). Weaker activity was observed in Vero E6 cells (EC50 = 1.65 M) due to their low capacity to metabolize RDV. To rapidly evaluate in vivo efficacy, we engineered a chimeric SARS-CoV encoding the viral target of RDV, the RNA-dependent RNA polymerase, of SARS-CoV-2. In mice infected with chimeric virus, therapeutic RDV administration diminished lung viral load and improved pulmonary function as compared to vehicle treated animals. These data provide evidence that RDV is potently active against SARS-CoV-2 in vitro and in vivo, supporting its further clinical testing for treatment of COVID-19.

microbiology↗

bioRxiv2017

MERS-CoV NSP16 necessary for IFN resistance and viral pathogenesis

Coronaviruses encode a mix of highly conserved and novel genes as well as genetic elements necessary for infection and pathogenesis, raising the possibility for common targets for attenuation and therapeutic design. In this study, we focus on the highly conserved nonstructural protein (NSP) 16, a viral 2O methyl-transferase (MTase) that encodes critical functions in immune modulation and infection. Using reverse genetics, we disrupted a key motif in the conserved KDKE motif of MERS NSP16 (D130A) and evaluated the effect on viral infection and pathogenesis. While the absence of 2O MTase activity had only marginal impact on propagation and replication in Vero cells, the MERS dNSP16 mutant demonstrated significant attenuation relative to control both in primary human airway cultures and in vivo. Further examination indicated the MERS dNSP16 mutant had a type I IFN based attenuation and was partially restored in the absence of IFIT molecules. Importantly, the robust attenuation permitted use of MERS dNSP16 as a live attenuated vaccine platform protecting from challenge with a mouse adapted MERS-CoV strain. These studies demonstrate the importance of the conserved 2O MTase activity for CoV pathogenesis and highlight NSP16 as a conserved universal target for rapid live attenuated vaccine design in an expanding CoV outbreak setting.\n\nSignificanceCoronavirus emergence in both human and livestock represents a significant threat to global public health, as evidenced by the sudden emergence of SARS-CoV, MERS-CoV, PEDV and swine delta coronavirus in the 21st century. These studies describe an approach that effectively targets the highly conserved 2O methyl-transferase activity of coronaviruses for attenuation. With clear understanding of the IFN/IFIT based mechanism, NSP16 mutants provide a suitable target for a live attenuated vaccine platform as well as therapeutic development for both current and future emergent CoV strains. Importantly, other approaches targeting other conserved pan-coronavirus functions have not yet proven effective against MERS-CoV, illustrating the broad applicability of targeting viral 2O MTase function across coronaviruses.

microbiology↗