# Cargo and Biological Properties of Extracellular Vesicles Released from Human Adenovirus Type 4-Infected Lung Epithelial Cells

## TL;DR

This study explores how human adenovirus type 4 infection alters the cargo and function of extracellular vesicles released from lung cells, suggesting a role in viral spread.

## Contribution

The study reveals that adenovirus-infected cells release extracellular vesicles containing viral DNA and proteins, enabling non-lytic viral dissemination.

## Key findings

- EVs from infected cells contain 268 unique proteins linked to viral processes and vesicle trafficking.
- AdV-EVs carry viral genomic DNA and can initiate infection in new cells without viral particles.
- Small non-coding RNAs, including snoRNAs and virus-associated RNAs, are differentially uploaded into EVs.

## Abstract

Extracellular vesicles (EVs) are rapidly gaining recognition as critical mediators of inter-cellular communication during viral infections. To contribute to fill the gap in knowledge regarding the role of EVs in adenovirus infection, we used human adenovirus type 4 of species Mastadenovirus exoticum (HAdV-E4), a prevalent respiratory and ocular pathogen, and characterized the cargo and biological properties of EVs released by HAdV-E4-infected A549 lung epithelial cells at a pre-lytic stage of infection. Using immunocapture-based isolation and multi-omics approaches, we found that infection profoundly alters the EV uploaded proteome and small non-coding RNA repertoire. Mass spectrometry identified 268 proteins unique to EVs purified from infected cells (AdV-EVs), with enrichment in pathways supporting vesicle trafficking and viral protein translation, and importantly also a few virus-encoded proteins. A small RNA transcriptome analysis showed differential uploading in AdV-EVs of various small non-coding RNAs, including snoRNAs, as well as the presence of virus associated RNAs I and II. Notably, AdV-EVs contained viral genomic DNA and could initiate productive infection upon delivery to naïve cells in the absence of detectable viral particles. Our data suggest that EVs released during the HAdV-E4 infection may serve as vehicles for non-lytic viral dissemination and highlight their possible role in intra-host dissemination