Biology subjects

Odle, A.

Publications and source records attributed to Odle, A..

5 recordsLinked to original sources

bioRxiv2025

Characterization of betacoronavirus HKU-1 and OC43 internal proteins using a prototypic coronavirus

Coronaviruses express a repertoire of accessory proteins for evading host immune responses. A small internal (I) accessory protein is expressed by the genus Betacoronavirus. Previous studies reported that the I proteins of SARS-CoV, MERS-CoV and SARS-CoV-2 inhibit type I interferon (IFN-I) expression through distinct mechanisms and have different roles in pathogenesis. Human coronaviruses (hCoV) HKU1 and OC43 are betacoronaviruses that also encode the I protein as an accessory protein. Although hCoV-HKU1 and hCoV-OC43 predominantly cause common cold in healthy adults, susceptible individuals infected with these viruses can develop severe disease. However, the virulence factors contributing to pathogenesis after infection with common cold CoVs (CCCoVs) have not been fully characterized. In particular, the functions of the hCoV-HKU1 and hCoV-OC43 I proteins have not been previously reported. The lack of robust reverse genetic systems, tissue culture and animal models limit the study of hCoV-HKU1 and hCoV-OC43 pathogenesis. Here, we examine the role of the hCoV-HKU1 and hCoV-OC43 I proteins in pathogenesis using a prototypic coronavirus. We introduce the I proteins of hCoV-HKU1 and hCoV-OC43 independently to a neurotropic strain of mouse hepatitis virus (J2.2). J2.2 infection is well characterized with clearly defined immune responses which allows the study of I proteins in the context of authentic coronavirus infection. We show that the I protein of hCoV-HKU1, but not that of hCoV-OC43, ameliorates MHV-J2.2 pathogenesis while the I protein of MERS-CoV exacerbates disease. The presence of the hCoV-HKU1 I protein decreases virus titers and cytokine expression while the I protein of MERS-CoV leads to increased immune cell infiltration and virus titers in mice after J2.2 infection. Moreover, the I proteins of hCoV-HKU1 and hCoV-OC43 show different patterns of subcellular localization. Overall, our findings suggest that the I protein of different betacoronaviruses play unique roles in pathogenesis. Author SummaryFactors governing the differences in the pathogenicity between highly pathogenic human coronaviruses (SARS-CoV, MERS-CoV and SARSR-CoV-2) and seasonal coronaviruses (hCoV-HKU1 and hCoV-OC43) are not completely understood. These differences are at least in part contributed to by the accessory proteins encoded between these two groups of human coronaviruses. The use of a heterologous coronavirus infection model provides an isogenic background for the direct comparison of viral proteins encoded by various coronaviruses. In this study, we compare the role of one of the accessory proteins encoded by betacoronaviruses, the I protein, in mediating disease outcome using a prototypic coronavirus. We demonstrate that the I protein of the highly pathogenic MERS-CoV but not that of the seasonal coronaviruses HKU1 and OC43 contributes to enhanced disease in the context of MHV-J2.2 infection, highlighting that virus-specific functions of accessory proteins encoded by different hCoVs.

microbiology↗

bioRxiv2024

TRIM7 ubiquitinates SARS-CoV-2 membrane protein to limit apoptosis and viral replication

SARS-CoV-2 is a highly transmissible virus that causes COVID-19 disease. Mechanisms of viral pathogenesis include excessive inflammation and viral-induced cell death, resulting in tissue damage. We identified the host E3-ubiquitin ligase TRIM7 as an inhibitor of apoptosis and SARS-CoV-2 replication via ubiquitination of the viral membrane (M) protein. Trim7-/- mice exhibited increased pathology and virus titers associated with epithelial apoptosis and dysregulated immune responses. Mechanistically, TRIM7 ubiquitinates M on K14, which protects cells from cell death. Longitudinal SARS-CoV-2 sequence analysis from infected patients revealed that mutations on M-K14 appeared in circulating variants during the pandemic. The relevance of these mutations was tested in a mouse model. A recombinant M- K14/K15R virus showed reduced viral replication, consistent with the role of K15 in virus assembly, and increased levels of apoptosis associated with the loss of ubiquitination on K14. TRIM7 antiviral activity requires caspase-6 inhibition, linking apoptosis with viral replication and pathology.

microbiology↗

bioRxiv2023

Functional and antigenic characterization of SARS-CoV-2 spike fusion peptide by deep mutational scanning

The fusion peptide of SARS-CoV-2 spike protein is functionally important for membrane fusion during virus entry and is part of a broadly neutralizing epitope. However, sequence determinants at the fusion peptide and its adjacent regions for pathogenicity and antigenicity remain elusive. In this study, we performed a series of deep mutational scanning (DMS) experiments on an S2 region spanning the fusion peptide of authentic SARS-CoV-2 in different cell lines and in the presence of broadly neutralizing antibodies. We identified mutations at residue 813 of the spike protein that reduced TMPRSS2-mediated entry with decreased virulence. In addition, we showed that an F823Y mutation, present in bat betacoronavirus HKU9 spike protein, confers resistance to broadly neutralizing antibodies. Our findings provide mechanistic insights into SARS-CoV-2 pathogenicity and also highlight a potential challenge in developing broadly protective S2-based coronavirus vaccines.

microbiology↗

bioRxiv2023

Evidence of antigenic drift in the fusion machinery core of SARS-CoV-2 spike

Antigenic drift of SARS-CoV-2 is typically defined by mutations in the N-terminal domain and receptor binding domain of spike protein. In contrast, whether antigenic drift occurs in the S2 domain remains largely elusive. Here, we perform a deep mutational scanning experiment to identify S2 mutations that affect binding of SARS-CoV-2 spike to three S2 apex public antibodies. Our results indicate that spatially diverse mutations, including D950N and Q954H, which are observed in Delta and Omicron variants, respectively, weaken the binding of spike to these antibodies. Although S2 apex antibodies are known to be non-neutralizing, we show that they confer partial protection in vivo. We further demonstrate that such in vivo protection activity is diminished by the natural mutation D950N. Overall, this study indicates that the S2 domain of SARS-CoV-2 spike can undergo antigenic drift, which represents a potential challenge for the development of more universal coronavirus vaccines.

microbiology↗

bioRxiv2020

The Development of a Novel Nanobody Therapeutic for SARS-CoV-2

Combating the COVID-19 pandemic requires potent and low-cost therapeutics. We identified a novel series of single-domain antibodies (i.e., nanobody), Nanosota-1, from a camelid nanobody phage display library. Structural data showed that Nanosota-1 bound to the oft-hidden receptor-binding domain (RBD) of SARS-CoV-2 spike protein, blocking out viral receptor ACE2. The lead drug possessing an Fc tag (Nanosota-1C-Fc) bound to SARS-CoV-2 RBD with a Kd of 15.7picomolar ([~]3000 times more tightly than ACE2 did) and inhibited SARS-CoV-2 infection with an ND50 of 0.16microgram/milliliter ([~]6000 times more potently than ACE2 did). Administered at a single dose, Nanosota-1C-Fc demonstrated preventive and therapeutic efficacy in hamsters subjected to SARS-CoV-2 infection. Unlike conventional antibody drugs, Nanosota-1C-Fc was produced at high yields in bacteria and had exceptional thermostability. Pharmacokinetic analysis of Nanosota-1C-Fc documented a greater than 10-day in vivo half-life efficacy and high tissue bioavailability. Nanosota-1C-Fc is a potentially effective and realistic solution to the COVID-19 pandemic. Impact statementPotent and low-cost Nanosota-1 drugs block SARS-CoV-2 infections both in vitro and in vivo and act both preventively and therapeutically.

microbiology↗