Biology subjects

Touzelet, O.

Publications and source records attributed to Touzelet, O..

3 recordsLinked to original sources

bioRxiv2024

Myoferlin is an essential component of late-stage vRNP trafficking vesicles for enveloped RNA viruses.

The Rab11a endosomal recycling pathway is exploited by important respiratory RNA viruses such as IAV and RSV, aiding viral egress from the apical surface of polarized epithelial cells. Late in infection, Rab11a-containing vesicles specifically transport viral ribonucleoprotein (vRNP) complexes towards the cell surface before packaging and budding. Rather than employing traditional Rab11a-positive recycling endosomes, virus-infected cells generate remodelled Rab11a-containing vesicles, as observed during IAV infection. Besides Rab11a, no other conserved host co-factors have been identified among these various vRNP trafficking vesicles. Here we discovered and confirmed myoferlins association with IAV vRNPs in the cytoplasm and colocalisation with Rab11a during late stages of infection. We also found that this role was conserved in late-stage vRNP trafficking of other viruses, including RSV and SeV. Myoferlin likely recruits the EHD family of proteins, which are involved in endosomal biogenesis, to these unique vRNP trafficking endosomes, highlighting myoferlins pivotal role in viral replication.

microbiology↗

bioRxiv2021

An Endogenously activated antiviral state restricts SARS-CoV-2 infection in differentiated primary airway epithelial cells

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the coronavirus disease-19 (COVID-19) pandemic, was identified in late 2019 and went on to cause over 3.3 million deaths in 15 months. To date, targeted antiviral interventions against COVID-19 are limited. The spectrum of SARS-CoV-2 infection ranges from asymptomatic to fatal disease. However, the reasons for varying outcomes to SARS-CoV-2 infection are yet to be elucidated. Here we show that an endogenously activated interferon lambda (IFN{lambda}) pathway leads to resistance against SARS-CoV-2 infection. Using a well-differentiated primary nasal epithelial cell (WD-PNEC) model from multiple adult donors, we discovered that susceptibility to SARS-CoV-2 infection, but not respiratory syncytial virus (RSV) infection, varied. One of four donors was resistant to SARS-CoV-2 infection. High baseline IFN{lambda} expression levels and associated interferon stimulated genes correlated with resistance to SARS-CoV-2 infection. Inhibition of the JAK/STAT pathway in WD-PNECs with high endogenous IFN{lambda} secretion resulted in higher SARS-CoV-2 titres. Conversely, prophylactic IFN{lambda} treatment of WD-PNECs susceptible to infection resulted in reduced viral titres. An endogenously activated IFN{lambda} response, possibly due to genetic differences, may be one explanation for the differences in susceptibility to SARS-CoV-2 infection in humans. Importantly, our work supports the continued exploration of IFN{lambda} as a potential pharmaceutical against SARS-CoV-2 infection.

immunology↗

bioRxiv2021

Collaboration Between Host and Viral Factors Shape SARS-CoV-2 Evolution

SARS-CoV-2 continues to evolve, resulting in several variants of concern with novel properties. The factors driving SARS-CoV-2 fitness and evolution in the human respiratory tract remain poorly defined. Here, we provide evidence that both viral and host factors co-operate to shape SARS-CoV-2 genotypic and phenotypic change. Through viral whole-genome sequencing, we explored the evolution of two clinical isolates of SARS-CoV-2 during passage in unmodified Vero-derived cell lines and in parallel, in well-differentiated primary nasal epithelial cell (WD-PNEC) cultures. We identify a consistent, rich genetic diversity arising in vitro, variants of which could rapidly rise to near-fixation with 2 passages. Within isolates, SARS-CoV-2 evolution was dependent on host cells, with Vero-derived cells facilitating more profound genetic changes. However, most mutations were not shared between strains. Furthermore, comparison of both Vero-grown isolates on WD-PNECs disclosed marked growth attenuation mapping to the loss of the polybasic cleavage site (PBCS) in Spike while the strain with mutations in NSP12 (T293I), Spike (P812R) and a truncation of ORF7a remained viable in WD-PNECs. Our work highlights the significant genetic plasticity of SARS-CoV-2 while uncovering an influential role for collaboration between viral and host cell factors in shaping viral evolution and fitness in human respiratory epithelium.

microbiology↗