# SHIV.D Infection Alters Production and Protein Composition of Myeloid-Derived Extracellular Vesicles

## TL;DR

This study shows that SHIV infection changes the production and protein content of myeloid-derived extracellular vesicles, which may contribute to neurological disease.

## Contribution

The study identifies specific EV subpopulations and their protein cargo changes in SHIV-infected models, linking them to neuroinflammation.

## Key findings

- SHIV.D infection increases TMEM119+ microglial and CD171+ neuronal EVs in rhesus macaque plasma.
- Myeloid-derived EVs from SHIV-infected macrophages show elevated neuropathogenic and inflammatory proteins.

## Abstract

Although neurological disease is common in people with human immunodeficiency virus (HIV) (PWH), the contributing factors and underlying inflammatory mechanisms remain challenging to identify. Extracellular vesicles (EVs) constitute a relatively uncharacterized modality of intercellular communication and bioactive cargo transport in the setting of viral infection and pathogenesis. EVs carry inflammatory mediators to areas of the periphery during antiretroviral therapy (ART) suppression but are understudied in the brain. Using a biologically relevant simian–human immunodeficiency chimeric virus with a clade D HIV envelope (SHIV.D)-infected rhesus macaque (RM) model of HIV persistence in the central nervous system (CNS), we investigate circulating EV populations and the protein cargo of myeloid-derived EVs during SHIV infection. Using EV flow cytometry to quantify specific EV subpopulations, we found a significant increase in TMEM119+ microglial EVs and CD171+ neuronal EVs in RM plasma during viremia and ART suppression. Using primary RM monocyte-derived macrophages (MDMs), we determined that MDMs increased EV production after SHIV infection. Whole proteomic analysis of these EVs demonstrated that myeloid EVs isolated from SHIV.D-infected MDMs carried significantly increased levels of neuropathogenic and inflammatory proteins. Altogether, these studies improve our understanding of the contribution of myeloid EVs to neurological disease during SHIV/HIV infection.