Biology subjects

Thornhill, E. M.

Publications and source records attributed to Thornhill, E. M..

3 recordsLinked to original sources

bioRxiv2024

SARS-CoV-2 Mediated Inhibition Of Respiratory Syncytial Virus

With circulation of SARS-CoV-2, fears about coinfection with other respiratory viruses such as influenza and RSV were significant, but the opposite was observed. Distancing/barriers played a major role in reducing other viral co-infections, however, some infrequent co-infections still occurred. We investigated the relationship between SARS-CoV-2 and RSV during coinfection to understand how they might compete or synergize. We found only RSVs replication was significantly reduced when coinfected with SARS-CoV-2. Investigation of the mechanism revealed that the SARS-CoV-2 protein Nsp1 disrupts the RSV M2-2 protein but not the upstream M2-1 protein on the same biscistronic mRNA transcript. The impact of Nsp1 on M2-2 was not dependent on M2-2 being the second ORF in a bicistronic mRNA transcript, but likely from prevention of ribosomal termination-reinitiation necessary for M2-2 production. Additional viral ORFs from influenza A, influenza B, or Sendai virus dependent on the same or other ribosomal initiation mechanisms were tested and we found only influenza B M/M2 which likely uses a similar method as M2-2 was disrupted. Various M2-2 constructs, with/without the proposed site of ribosomal termination-reinitiating, co-transfected with Nsp1 and were in agreement that disruption to M2-2 expression occurs if the site of re-initiation was present upstream. These data not only suggest Sars-CoV-2 can outcompete RSV through suppression of M2, but may also point to potential ways to interfere with RSV by targeted therapies.

microbiology↗

bioRxiv2024

RESPIRATORY SYNCYTIAL VIRUS NON-STRUCTURAL PROTEIN EXPRESSION ARE LIMITED IN NEUTROPHILS

Respiratory Syncytial Virus (RSV) is a negative stranded RNA virus with a high incidence of secondary bacterial infections. RSV contains two broad immune inhibitory proteins Ns1 and Ns2 which are not present in any other viruses of the Mononegavirales Order. Here we report that expression of Ns2 is attenuated during RSV infection of neutrophils and that RSV is indeed infecting neutrophils rather than simply being phagocytosed by them. Infection was determined by intracellular staining and coinfection studies of uninfected Hep2 cells. The significant attenuation of Ns2 in vivo along with the low abundance of coinfected cells indicates that RSV infection is likely functionally non permissive in in vivo infection. The implications of RSV infection of neutrophils may explain the previously observed phenomenon of decreased phagocytosis in neutrophils exposed to RSV and the lack of Ns2 expression within neutrophils may provide avenues of study to attenuate viral infection through therapy development.

immunology↗

bioRxiv2024

ANALYSIS OF RESPIRATORY SYNCYTIAL VIRUS REVEALS CONSERVED RNA SECONDARY STRUCTURAL MOTIFS AND IMPACT VIRAL LIFECYCLE

An analysis that combined bioinformatics, comparative sequence/structural analysis, and experimental assays has been completed on respiratory syncytial virus (RSV). Both the genomic RNA and its reverse complement were studied using the novel bioinformatics pipeline ScanFold, which predicted 49 regions on RSV RNAs that appear to encode functional secondary structures (based on their unusually stable sequence order). Multiple motifs appear to be conserved between RSV and related virus strains, including one region within the F gene, which had a highly favorable overall prediction metric of a paired secondary structure. This motif was subjected to additional experimental analyses using SHAPE analysis to confirm ScanFold predicted secondary structure. In subsequent analysis, RSV F mRNA transcripts were made by in vitro transcription using T7 polymerase and transcripts which relaxed the predicted secondary structure yielded slightly higher mRNA transcripts and protein expression levels as wildtype F. However, using reverse genetics for comparison of viruses containing wildtype or relaxed F suggested that the predicted secondary structures may be critical for RSV replication in cells. To our knowledge, this is the first study to examine conserved RNA structures across multiple RSV strains and may help identify potential therapeutic targets to inhibit.

microbiology↗