Researchers map how measles virus spreads in human brain - Mayo Clinic

[Mary Wilson]

December 21, 2023

ROCHESTER, Minn. — Mayo Clinic researchers mapped how the measles virus mutated and spread in the brain of a person who succumbed to a rare, lethal brain disease. New cases of this disease, which is a complication of the measles virus, may occur as measles reemerges among the unvaccinated, say researchers.

Using the latest tools in genetic sequencing, researchers at Mayo Clinic reconstructed how a collective of viral genomes colonized a human brain. The virus acquired distinct mutations that drove the spread of the virus from the frontal cortex outward.

"Our study provides compelling data that shows how viral RNA mutated and spread throughout a human organ — the brain, in this case," says Roberto Cattaneo, Ph.D., a Mayo Clinic virologist who is a co-lead author on a new PLOS Pathogens study. ...

https://newsnetwork.mayoclinic.org/...map-how-measles-virus-spreads-in-human-brain/

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[Mary Wilson]

Brain Tropism acquisition: The spatial dynamics and evolution of a measles virus collective infectious unit that drove lethal subacute sclerosing panencephalitis - PLOS

Published: December 21, 2023

https://doi.org/10.1371/journal.ppat.1011817​

Iris Yousaf, William W. Hannon, Ryan C. Donohue, Christian K. Pfaller, Kalpana Yadav, Ryan J. Dikdan, Sanjay Tyagi, Declan C. Schroeder, Wun-Ju Shieh, Paul A. Rota, Alison F. Feder, Roberto Cattaneo​

Abstract

It is increasingly appreciated that pathogens can spread as infectious units constituted by multiple, genetically diverse genomes, also called collective infectious units or genome collectives. However, genetic characterization of the spatial dynamics of collective infectious units in animal hosts is demanding, and it is rarely feasible in humans. Measles virus (MeV), whose spread in lymphatic tissues and airway epithelia relies on collective infectious units, can, in rare cases, cause subacute sclerosing panencephalitis (SSPE), a lethal human brain disease. In different SSPE cases, MeV acquisition of brain tropism has been attributed to mutations affecting either the fusion or the matrix protein, or both, but the overarching mechanism driving brain adaptation is not understood. Here we analyzed MeV RNA from several spatially distinct brain regions of an individual who succumbed to SSPE. Surprisingly, we identified two major MeV genome subpopulations present at variable frequencies in all 15 brain specimens examined. Both genome types accumulated mutations like those shown to favor receptor-independent cell-cell spread in other SSPE cases. Most infected cells carried both genome types, suggesting the possibility of genetic complementation. We cannot definitively chart the history of the spread of this virus in the brain, but several observations suggest that mutant genomes generated in the frontal cortex moved outwards as a collective and diversified. During diversification, mutations affecting the cytoplasmic tails of both viral envelope proteins emerged and fluctuated in frequency across genetic backgrounds, suggesting convergent and potentially frequency-dependent evolution for modulation of fusogenicity. We propose that a collective infectious unit drove MeV pathogenesis in this brain. Re-examination of published data suggests that similar processes may have occurred in other SSPE cases. Our studies provide a primer for analyses of the evolution of collective infectious units of other pathogens that cause lethal disease in humans.

https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1011817


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