Project description:In 2014, enterovirus D68 (EV-D68), previously associated primarily with mild respiratory illness, caused a large outbreak of severe respiratory illness and, in rare instances, paralysis. We compared viral binding and replication of eight recent EV-D68 clinical isolates and the prototype Fermon strain from 1962 in cultured HeLa cells and differentiated human primary bronchial epithelial cells (BEC) to understand the possible reasons for the change in virus pathogenicity. We found no significant differences in binding or replication in HeLa cell cultures between the recent clinical isolates. However, in HeLa cells, Fermon had significantly greater (1.5-2 log) binding and virus progeny yields but a similar level of replication (~2-log increase in viral RNA from 2h to 24h post infection) compared to recent isolates. In differentiated BECs, Fermon and the recent EV-D68 isolates had similar levels of binding; however, the recent isolates produced 1-2-log higher virus progeny yields than Fermon due to increased replication. We then utilized RNA-seq to define the transcriptional responses in BECs infected with four recent EV-D68 isolates, representing major phylogenetic clades, and Fermon strain. All the tested clinical isolates induced similar responses in BECs; however, numerous upregulated genes in antiviral and pro-inflammatory response pathways were identified when comparing the response to clinical isolates versus Fermon. These results indicate that the recent emergence in severe EV-D68 cases could be explained by increased replication efficiency and enhanced inflammatory response induced by newly emerged clinical isolates.
Project description:Enteroviruses (EVs) are one of the most prevalent viruses worldwide. They are characterised by a high genetic and phenotypic diversity, being able to cause a plethora of symptoms. EV-D68, a respiratory EV, and EV-D94, an enteric EV, represent an interesting paradigm of EV tropism heterogeneity. These are closely related viruses, belonging to the same species, but with distinct phenotypic features. Here, we used these two viruses as well as relevant tissue culture models mimicking the respiratory and intestinal epithelia, to highlight key distinctive features of enteric and respiratory EVs. We emphasize the critical role of temperature in restricting the tissue tropism of EV-D68 and the limited replication of EV-D94 in small airway tissues. In parallel, using transcriptomic analysis, we uncover fundamental differences between intestinal and respiratory tissues, in their steady-state as well as in response to infection. Intestinal tissues are more immunotolerant than respiratory tissues both in absence and presence of infection and they present higher turnover. Finally, we highlight the different strategies applied by EV-D94 and EV-D68 towards the host antiviral response in intestinal and respiratory tissues. In summary, our study provides an insightful characterization of the differential pathogenesis of EV-D68 and EV-D94 and the interplay with their main target tissues.
Project description:Enterovirus 71 (EV71) and Coxsackievirus A16 (CA16) are the predominant etiological agents of hand, foot, and mouth disease (HFMD) and both belong to the human enterovirus A species of the Picornaviridae family. These viruses share similar genetic homology, although the clinical manifestations of HFMD caused by the two viruses have some discrepancies. Furthermore, the underlying mechanisms leading to these differences remain unclear. microRNAs (miRNAs) participate in numerous biological or pathological processes, including host responses to viral infections, by targeting messenger RNAs (mRNAs) for translational repression or degradation. Here, we focused on differences in miRNA expression patterns in peripheral blood mononuclear cells (PBMCs) of rhesus monkeys infected with EV71 or CA16 at different time points using high-throughput sequencing technology. For the first time, this study demonstrated that EV71 and CA16 infection result in specific miRNA expression patterns in PBMCs.
Project description:Enterovirus-D68 genomic sequencing of 2014 US outbreak strains to understand its evolutionary dynamics and increased disease severity