rologie i - European Congress of Virology

5 th European Congress of Virologyduring viral infection. NS1 has been implicated in viral RNA replication(Khromykh et al. Journal of Virology 1999), and regulation of the hostimmune response (Chung et al. PNAS 2006). A larger NS1 related protein,NS1’, is produced via ribosomal frameshifting and plays a criticalrole in JEV neuroinvasiveness (Melian et al. Journal of Virology 2010).In the present study, we identified a single amino acid substitution in NS1that attenuates the virulence of JEV strain RP9 in a mouse model. Usinga molecular clone of JEV RP9, we demonstrated that this mutation abolishesthe neuroinvasiveness but not the neurovirulence of JEV RP9 inthree week old Balb/c mice. Interestingly, this mutation had no impact onviral RNA replication, and did not have any effect on JEV RP9 infectiouscycle in cell culture. Studies are ongoing to assess whether this mutationaffects JEV NS1 capacity to subvert the antiviral immune responses.REF O22Activation of the potentially neuropathogenic HERV W/MSRV typeendogenous retrovirus during severe infectious mononucleosis andpast Epstein Barr virus infection: the missing link with multiple sclerosis?Antonina DOLEI 1 , Giuseppe MAMELI 1 , Giordano MADEDDU 2 ,Alessandra MEI 1 , Elena ULERI 1 , Luciana PODDIGHE 1 , IvanaMAIDA 2 , Sergio BABUDIERI 2 , Caterina SERRA 1 , MariastellaMURA 21 Department of Biomedical Sciences, University of Sassari, Sassari,ITALY; 2 Department of Clinical and Experimental Medicine, Universityof Sassari, Sassari, ITALYThe etiology of multiple sclerosis (MS) is still unclear. Proposed viral cofactors are the Epstein Barr virus (EBV), and the potentially neuropathogenicHERV W/MSRV/Syncytin 1 endogenous retroviruses. The ascertainedEBV/MS links are history of late primary infection, possibly leading toinfectious mononucleosis (IM), and high titers of pre onset IgG againstEBV nuclear antigens (anti EBNA IgG). There is no evidence of MS specificEBV expression during MS, while a continuous HERV W expressionoccurs. We found repeatedly extracellular HERV W/MSRV and MSRVspecific mRNA sequences in MS patients, and MRSV presence/load strikinglyparalleled MS stages and phases. To verify whether HERV W mightbe activated in vivo, young adults hospitalized for IM were analyzed forexpression of HERV W/MSRV transcripts and proteins. Healthy controlswere either EBV() or latently EBV infected with/without high titers ofanti EBNA IgG. The results show that HERV W/MSRV activation occursin blood mononuclear cells of patients hospitalized for IM. When healthycontrols are stratified for high, low, or no anti EBNA IgG titers, this tightlycorrelates to the extent of HERV W/MSRV activation. Thus, the data indicatethat the two main links between EBV and MS (IM and high antiEBNA IgG titers) are paralleled by activation of the potentially neuropathogenicHERV W/MSRV. These novel findings suggest that the activationof HERV W/MSRV is the missing link between EBV and MS, and mayopen new avenues of intervention.REF O23Perturbation of neuronal signaling pathways by the rabies virusNicolas WOLFF 1,3,4 , Pierre MAISONNEUVE 1,3,6 , ElouanTERRIEN 1,3,6 , Célia CAILLET 1,3,4 , Mireille LAFAGE 1,2,5 , FlorenceCORDIER 1,3,4 , Christophe PRÉHAUD 1,2,5 , Henri BUC 1 , MurielDELEPIERRE 1,3,4 , Monique LAFON 1,2,51 Institut Pasteur, Paris, FRANCE; 2 Unité de NeuroImmunologie ViraleDépartement de Virologie, Paris, FRANCE; 3 Unité de RMN des BiomoléculesDépartement de Biologie Structurale et Chimie, Paris, FRANCE;4 CNRS UMR3528, Paris, FRANCE; 5 CNRS UMR3015, Paris, FRANCE;6 Université Pierre et Maris Curie, Paris, FRANCEThe human tyrosine phosphatase PTPN4 and the Microtubule associatedSer/Thr kinase 2 (MAST2) are two enzymes expressed in neurons. WhilePTPN4 is an anti apoptotic protein, MAST2 inhibits neurogenesis andneuroprotection. The PDZ domain of these two enzymes is specifically targetedby the cytoplasmic domain of the envelope glycoprotein (G protein)of the rabies virus (RABV) during neuron infection (Préhaud et al, 2010).As a result, the complexes formed by the PDZ of the two enzymes and theirrespective ligands are disrupted, triggering drastic effect on cell signalingand cell commitment either towards death or survival. By targeting MAST2PDZ, the G protein of virulent RABV alters the intracellular trafficking ofPTEN (Terrien et al., 2012) and promotes survival, whereas the G proteinof attenuated RABV induces neuronal cell death by targeting PTPN4 PDZ.We recently demonstrated that the catalytic activity of PTPN4 is regulatedby its PDZ domain and that the viral sequence interfered with this allostericregulation.We provided structural and biological evidences that the RABV Gproteins act as competitors endowed with specificity and sufficient affinityin a vital cellular process. The disruption of critical endogenousprotein protein interactions by viral protein altered drastically intracellularprotein trafficking and catalytic activity controlling the cellularhomeostasis.Terrien E, et al. Science Signal 2012; 5 (237): ra58.Babault, et al. Structure 2011; 19: 1518 1524.Préhaud, C et al. Science Signal 2010; 3 (105): ra5.REF O24Infection and crossing of an in vitro cellular model of human bloodbrain barrier by a large array of neurotropic enterovirusesRomain VOLLE 1,2 , Christine ARCHIMBAUD 1,2 , CécileHENQUELL 1,2 , Audrey MIRAND 1,2 , Martine CHAMBON 1,2 , HélènePEIGUE LAFEUILLE 1,2 , Jean Luc BAILLY 1,21 Université d’Auvergne, Faculté de Médecine, EPIE EA4843, ClermontFerrand, France; 2 CHU de Clermont Ferrand, Laboratoire de virologie,Centre National de Référence Entérovirus/Parechovirus – Laboratoireassocié, Clermont Ferrand, FRANCEHuman enteroviruses (EVs) are associated with neurological conditions(meningitis, encephalitis, and acute flaccid paralysis) but theirentry into the central nervous system (CNS) remains poorly understood.Infection of the blood brain barrier may represent an access pathwayto the CNS common to most neurotropic EVs. We used a humanbrain microvascular endothelial cell line (hCMEC/D3) to investigate thishypothesis.Cytotoxic effects in non polarized hCMEC/D3 cells were assessed byRT qPCR, virus infectivity, and infection kinetics for 88 EV strains(43 serotypes). Two virus groups were characterized in the screeninganalysis. Cytotoxic viruses, in contrast to replicating but poorly cytotoxicEVs, caused statistically significant cell death through necrosisand apoptosis. Confocal and electron microscopy observations showedpatterns of intra cellular injuries common to both virus groups: actindepolymerization, mitochondria relocation in the perinuclear space, andinduction of vesicular structures suggestive of viral factories. Endothelialbarriers generated in vitro by culture of hCMEC/D3 cells on a microporousmembrane were productively infected by cytotoxic EVs, whichaltered the barrier permeability within 24 hours. Poorly cytotoxic EVshad no effect on barrier permeability over at least 96 hours of productiveinfection.This study provides consistent data indicating that human cerebral microvascularendothelial cells are susceptible to a large array of EV types andsuggests two pathways for the infection of brain parenchyma from virusespresent in the blood.S46 Virologie, Vol 17, supplément 2, septembre 2013