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Factors modulating rhinovirus and enterovirus pathogenicity

English title Factors modulating rhinovirus and enterovirus pathogenicity
Applicant Tapparel Vu Caroline
Number 184777
Funding scheme Project funding
Research institution Dépt Microbiologie et Médecine Moléculaire Faculté de Médecine Université de Genève
Institution of higher education University of Geneva - GE
Main discipline Experimental Microbiology
Start/End 01.04.2019 - 31.03.2023
Approved amount 588'000.00
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Keywords (8)

tissue culture; respiratory; rhinovirus; pathogenesis; enterovirus; model system; neurotropism; asthma

Lay Summary (French)

Lead
Les rhinovirus (RV) et entérovirus (EV) sont des causes majeures d’infections chez l’homme. Ces virus très variables appartiennent au genre Entérovirus dans la famille Picornaviridae, et sont associés à une grande variété de maladies différentes allant du rhume à la paralysie. Les Entérovirus peuvent être classés en deux groupes distincts sur la base de leur site principal de réplication. On distingue les entérovirus respiratoires qui ont un tropisme restreint pour les voies respiratoires et les entérovirus entériques, qui se multiplient principalement dans la muqueuse intestinale avant de disséminer vers d'autres tissus. Notre objectif est de mieux comprendre la pathogenèse de ces virus et leurs interactions avec leur hôte et avec d'autres pathogènes en utilisant des modèles de tissus humains reconstitués in vitro.
Lay summary

Contenu et objectifs du travail de recherche :

  • Nous avons mis en évidence deux mutations dans la protéine de capside de l’Entérovirus 71 (EV71), un important pathogène humain, et montré que ces mutations permettent au virus d'utiliser les héparanes sulfates comme récepteur d'attachement. De plus l'utilisation de ce récepteur semble favoriser la dissémination et le neurotropisme du virus. Nous projetons ici:

    - d'étudier comment la liaison aux héparanes sulfates module le cycle infectieux d'EV71 in vitro et dans des tissus intestinaux 

    - de confirmer l'impact de la mutation conférant la capacité à lier les héparanes sulfates, in vivo dans un modèle murin en comparant la virulence de virus liant ou non les héparanes sulfates

    Ceci nous permettra de mieux comprendre les déterminants de la neurovirulence d’EV71.
  • Nous avons pu montrer grâce à la création de virus chimériques entre un entérovirus respiratoire (EV68) et un entérovirus entérique (EV94) que les protéines de capsides confèrent une résistance différente à l'acidité et jouent un rôle critique dans le tropisme viral. Nous allons poursuivre ces constructions de virus chimériques pour mieux comprendre le rôle des protéines non structurelles dans les relations avec la cellule hôte (par exemple l'induction de l'interféron).
  • Nous allons comparer la pathogénèse de virus respiratoires dans des tissus 3D sains ou dérivés de patients asthmatiques. Nous allons également étudier les interactions de ces virus avec d’autres pathogènes respiratoires (virus ou bactéries).
  • Nous allons caractériser des EV ou RV associés à des maladies sévères pour identifier des facteurs de virulence.

Contexte scientifique et social du projet de recherche

Cette recherche permettra d'améliorer la connaissance des déterminants génomiques associés à des traits phénotypiques tels que la virulence et le neurotropisme, ainsi que la manière dont les RV et EV interagissent avec leurs hôtes et avec d'autres agents pathogènes. Cette connaissance est essentielle dans le contexte du développement de médicaments et de vaccins contre ces virus.

Direct link to Lay Summary Last update: 02.04.2019

Responsible applicant and co-applicants

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Project partner

Associated projects

Number Title Start Funding scheme
180323 Novel virucidal drugs: From basic to in vivo studies 01.10.2018 Sinergia
166218 Viral and host factors modulating rhinovirus and enterovirus disease severity 01.04.2016 Project funding
127159 Picornavirus respiratoires: variabilité génomique et adaptation 01.01.2010 Project funding

Abstract

Rhinoviruses (RVs) and enteroviruses (EVs) belong to the Enterovirus genus within the Picornaviridae family and are among the most prevalent infectious agents worldwide. They cause a wide range of diseases from common cold to severe neurological pathologies. In line with their diversity (> 260 human infecting types), their pathogenesis remains poorly characterized and has been mostly studied in vitro or in animal models. Here, we intend to continue our previous research projects, using relevant human tissue culture models. Enterovirus A71 is considered the most important neurotropic EV after poliovirus, and despite intensive investigations, its neurotropic determinants remain ill defined. We have previously identified a mutation in the EV-A71 VP1 capsid protein acquired during a disseminated infection in an immunocompromised patient and have shown that this mutation confers the ability to use the heparan sulfate (HS) attachment receptor, thus affecting viral tropism in respiratory, intestinal and neural tissues. We also observed that HS binding modulates viral growth in vitro. We now plan to further explore the differences between EV-A71 HS-dependent and HS-independent variants by comparing each step of the viral life cycle. In parallel, we will compare infections caused by the two variants after inoculation of immunocompetent mice or in mice treated with anti-CD20 antibodies to mimic the immunosuppressed status of the patient. This will indicate the respective role of viral (ability to bind HS) and host factors (immune status) in promoting EV-A71 dissemination and virulence in vivo. EVs can be divided into respiratory or enteric EVs based on their in vivo tropism. Thanks to artificially engineered chimeras between a respiratory (EV-D68) and an enteric (EV-D94) EV, we have highlighted the importance of the capsid in defining viral tropism, acid and temperature sensitivity. We have also shown that capsid exchanges do not affect antiviral responses. We will use a similar approach and measure interferon (IFN) induction after infection of respiratory, intestinal and neural tissues with viruses chimeric at the nonstructural proteins level. This will help to understand how EV nonstructural proteins antagonize the host antiviral response. RVs account for up to 80% of common colds and are the most frequent cause of asthma exacerbations. RVs from species C use CDHR3 as a receptor and a study showed an association between a CDHR3 polymorphism and childhood asthma with severe exacerbations. We will use respiratory tissues reconstituted from asthmatic patients, with or without the CDHR3 susceptibility allele, to compare the replication of RVs from different species. If a difference is observed, the potential role of tissue IFN response or receptor expression and accessibility will be investigated via elisa, transcriptome analysis and immunohistochemistry. Co-infections by distinct respiratory pathogens are frequently reported. We will also study virus-virus and virus-bacteria interactions in cells and tissues. Preliminary results of viral coinfections in tissues showed that RVs are inhibited by influenza (Flu) and respiratory syncytial virus (RSV) but not by coronavirus OC43. RSV is inhibited by Flu but Flu is not inhibited by any of these viruses. We also observed that inhibition is not dependent on blocking viral entry. We will thus investigate a possible implication of type I or type III IFN by analyzing the replication of each virus in cells or tissues pre-treated with these cytokines. In addition, we will perform single or dual infections of cells and tissues knocked-down for the type III IFN receptor or for STAT1 (involved in type I and type III IFN pathways). These experiments will be completed by single cell RNA sequencing of dually infected respiratory tissues to finely dissect the response of single or dually infected cells and of uninfected neighboring cells. Concerning virus-bacteria interactions, we will question a direct or cell-mediated effect of bacteria commonly detected in patients with respiratory diseases, on RV infection. To this end, we will preincubate RV and bacteria before infection or incubate bacteria and cells before viral infection. If enhancement or inhibition is observed, this will be confirmed in respiratory tissues and the underlying mechanisms will be investigated. These projects are the logical follow-up to our previous work. They address fundamental questions regarding the pathogenesis of respiratory and non-respiratory EVs. The findings will help deepen our understanding of the important aspects of enterovirus-host interactions and will help optimize patient care and ultimately, develop novel, effective treatments.
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