Search bioRxiv⌕ Search

Biology subjects

Slough, M. M.

Publications and source records attributed to Slough, M. M..

4 recordsLinked to original sources

Finding the Goldilocks zone: Modulating glycoprotein cleavage and fusogenicity optimizes the efficacy of a candidate Crimean-Congo hemorrhagic fever virus vaccine

Crimean-Congo hemorrhagic fever virus (CCHFV) is the etiologic agent of a lethal hemorrhagic disease spread by ticks throughout Europe, the Middle East, Africa and Asia. The lack of approved medical countermeasures and fundamental understanding of molecular mechanisms of viral assembly and egress have thus far curtailed disease prevention. Here, we identify and characterize key residues within the viral glycoprotein through forward and reverse genetics for vesicular stomatitis virus (VSV)-based vaccine candidates that are highly protective in animal models. These residues are broadly applicable across divergent CCHFV strains and lead to greater protection in vivo against heterologous challenge. We further characterize the essential role of proteolytic processing in the maintenance of a stable fusogenic state required for effective VSV-based CCHFV vaccines. This study establishes a toolkit for better understanding orthonairovirus glycoprotein processing and vaccine development.

microbiology↗

High-resolution in situ structures of hantavirus glycoprotein tetramers

SUMMARY/ABSTRACTNew World hantaviruses cause severe infections in humans, with case fatality rates approaching 40%. Previous structural studies have advanced our understanding of hantavirus glycoprotein architecture and function, however, the lack of high-resolution in situ structures of the glycoprotein tetramer and its lattice organization has limited mechanistic insights into viral assembly, entry, and antigenicity. Here, we leveraged a virus-like particle (VLP) system to establish a cryo-electron microscopy workflow for lattice-forming viral glycoproteins. This enabled the determination of a 2.35 [A] resolution structure of the membrane-embedded Andes virus (ANDV) glycoprotein tetramer, as well as structures of dimers of tetramers and a complex with antibody ADI-65534. These structures reveal previously uncharacterized features of glycoprotein organization, stability, and pH-sensing. Immunization of mice with self-amplifying replicon RNA (repRNA) encoding ANDV-VLPs elicited high levels of glycoprotein-binding antibodies but equivalent titers of neutralizing antibodies compared to repRNA-encoded native ANDV glycoprotein complex. Collectively, these findings advance our understanding of hantavirus glycoprotein assemblies and their function, laying a foundation for structure-based vaccine design efforts.

microbiology↗

Two point mutations in protocadherin-1 disrupt Andes hantavirus recognition and afford protection against lethal infection

Andes virus and Sin Nombre virus are the etiologic agents of severe hantavirus cardiopulmonary syndrome (HCPS) in the Americas for which no FDA-approved countermeasures are available. Protocadherin-1 (PCDH1), a cadherin-superfamily protein recently identified as a critical host factor for ANDV and SNV, represents a new antiviral target; however, its precise role remains to be elucidated. Here, we used computational and experimental approaches to delineate the binding surface of the ANDV glycoprotein complex on PCDH1s first extracellular cadherin repeat domain. Strikingly, a single amino acid residue in this PCDH1 surface influenced the host species-specificity of SNV glycoprotein-PCDH1 interaction and cell entry. Mutation of this, and a neighboring residue, substantially protected Syrian hamsters from pulmonary disease and death caused by ANDV. We conclude that PCDH1 is a bona fide entry receptor for ANDV and SNV whose direct interaction with hantavirus glycoproteins could be targeted to develop new interventions against HCPS.

microbiology↗

Two point mutations in the Hantaan virus glycoproteins afford the generation of a highly infectious recombinant vesicular stomatitis virus vector

Rodent-to-human transmission of hantaviruses is associated with severe disease. Currently, no FDA-approved, specific antivirals or vaccines are available, and the requirement for high biocontainment (BSL3) laboratories limits hantavirus research. To study hantavirus entry in a BSL-2 laboratory, we set out to generate replication-competent, recombinant vesicular stomatitis viruses (rVSVs) bearing the Gn/Gc entry glycoproteins. As previously reported, rVSVs bearing New World hantavirus Gn/Gc were readily rescued from cDNAs, but their counterparts bearing Gn/Gc from the Old World hantavirus, Hantaan virus (HTNV), were refractory to rescue and only grew to low titers. However, serial passage of the rescued rVSV-HTNV Gn/Gc virus markedly increased its infectivity and capacity for cell-to-cell spread. This gain in viral fitness was associated with the acquisition of two point mutations; I532K in the cytoplasmic tail of Gn, and S1094L in the membrane-proximal stem of Gc. Follow-up experiments with rVSVs and single-cycle VSV pseudotypes confirmed these results. Mechanistic studies revealed that both mutations were determinative and contributed to viral infectivity in a synergistic manner. Our findings indicate that the primary mode of action of these mutations is to relocalize HTNV Gn/Gc from the Golgi complex to the cell surface, thereby affording significantly enhanced Gn/Gc incorporation into budding VSV particles. Our results suggest that enhancements in cell-surface expression of hantaviral glycoprotein(s) through incorporation of cognate mutations could afford the generation of rVSVs that are otherwise challenging to rescue. The robust replication-competent rVSV-HTNV Gn/Gc reported herein may also have utility as a vaccine.\n\nImportanceHuman hantavirus infections cause pulmonary syndrome in the Americas and hemorrhagic fever with renal syndrome (HFRS) in Eurasia. No FDA-approved vaccines and therapeutics exist for these deadly viruses, and their development is limited by the requirement for high biocontainment. In this study, we identified and characterized key amino acid changes in the surface glycoproteins of HFRS-causing Hantaan virus that enhance their incorporation into recombinant vesicular stomatitis virus (rVSV) particles. The replication-competent rVSV genetically encoding Hantaan virus glycoproteins described in this work provides a powerful and facile system to study hantavirus entry under lower biocontainment and may have utility as a hantavirus vaccine.

microbiology↗