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Measles virus exits human airway epithelia within dislodged metabolically active infectious centers
Journal article   Open access   Peer reviewed

Measles virus exits human airway epithelia within dislodged metabolically active infectious centers

Camilla E Hippee, Brajesh K Singh, Andrew L Thurman, Ashley L Cooney, Alejandro A Pezzulo, Roberto Cattaneo and Patrick L Sinn
PLoS pathogens, Vol.17(8), pp.e1009458-e1009458
08/2021
DOI: 10.1371/journal.ppat.1009458
PMCID: PMC8384213
PMID: 34383863
url
https://doi.org/10.1371/journal.ppat.1009458View
Published (Version of record) Open Access

Abstract

Measles virus (MeV) is the most contagious human virus. Unlike most respiratory viruses, MeV does not directly infect epithelial cells upon entry in a new host. MeV traverses the epithelium within immune cells that carry it to lymphatic organs where amplification occurs. Infected immune cells then synchronously deliver large amounts of virus to the airways. However, our understanding of MeV replication in airway epithelia is limited. To model it, we use well-differentiated primary cultures of human airway epithelial cells (HAE) from lung donors. In HAE, MeV spreads directly cell-to-cell forming infectious centers that grow for ~3-5 days, are stable for a few days, and then disappear. Transepithelial electrical resistance remains intact during the entire course of HAE infection, thus we hypothesized that MeV infectious centers may dislodge while epithelial function is preserved. After documenting by confocal microscopy that infectious centers progressively detach from HAE, we recovered apical washes and separated cell-associated from cell-free virus by centrifugation. Virus titers were about 10 times higher in the cell-associated fraction than in the supernatant. In dislodged infectious centers, ciliary beating persisted, and apoptotic markers were not readily detected, suggesting that they retain functional metabolism. Cell-associated MeV infected primary human monocyte-derived macrophages, which models the first stage of infection in a new host. Single-cell RNA sequencing identified wound healing, cell growth, and cell differentiation as biological processes relevant for infectious center dislodging. 5-ethynyl-2'-deoxyuridine (EdU) staining located proliferating cells underneath infectious centers. Thus, cells located below infectious centers divide and differentiate to repair the dislodged infected epithelial patch. As an extension of these studies, we postulate that expulsion of infectious centers through coughing and sneezing could contribute to MeV's strikingly high reproductive number by allowing the virus to survive longer in the environment and by delivering a high infectious dose to the next host.
Cells, Cultured Epithelial Cells - metabolism Epithelial Cells - virology Humans Macrophages - metabolism Macrophages - virology Measles - genetics Measles - metabolism Measles - virology Measles virus - pathogenicity Respiratory System - metabolism Respiratory System - virology RNA-Seq Single-Cell Analysis Transcriptome Virus Internalization Virus Replication

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