Brain cortical large extracellular vesicle proteins indicate high prevalence of SIV/SHIV-associated neuropathogenesis in female versus male rhesus macaques

Background: Antiretroviral therapy suppresses HIV-1 replication and improves survival, yet many individuals still develop HIV associated neurocognitive disorders (HAND). An intriguing (but poorly understood) clinical finding shows that HAND is more prevalent in women than in men. The mechanisms for this sex-specific prevalence are unclear. Neuro-HIV manifests in neurostructural alterations, and the secretory capacities of central nervous system (CNS) cells are modified by such alterations, as reflected by extracellular vesicles (EVs) released by CNS cells. Our study reveals sexual dimorphism in SIV (simian immunodeficiency virus)/SHIV (simian-human immunodeficiency virus)-induced proteome changes of brain cortical large EVs (LEVs) and their likely association with a higher prevalence of cognitive impairment in females. Methods: We isolated cerebral cortex-derived LEVs from infected (n = 10; 5 males and 5 females; age: 9.8 ± 4.4 years) and uninfected (n = 7; 3 males and 4 females; age: 9.2 ± 2.1 years) adult rhesus macaques (RMs). LEVs were isolated by differential centrifugation (20,000 × g for 30 min) and characterized by ZetaView analyzer and transmission electron microscopy. Proteomic and bioinformatic analyses of LEVs were performed using liquid chromatography-mass spectrometry and Ingenuity Pathway Analysis (IPA), respectively. Key differentially expressed proteins (DEPs) and EV markers were further validated by western blots. Results: The median size (≈180 nm) and zeta potential (≈ -43 mV) of LEVs between infected males and females were similar. LEVs concentrations were significantly higher (p = 0.0037) in infected vs. uninfected RMs; however, they were comparable between males and females. By proteomics, 3288 proteins (66.2%) were downregulated, and 1681 proteins (33.8%) were upregulated in infected females compared with males. IPA analysis of downregulated DEPs in females vs males (fold change < -1.5; n = 1130) indicated that several neurological disorders/diseases were activated more in infected females (z-score ≥ 2.0) than in uninfected female LEVs. Moreover, infected female LEVs experienced deactivation of several CNS functions (z-score ≤ -2.0). Sixteen DEPs were significantly (p < 0.05) downregulated in infected female RMs compared with infected males. Interestingly, none of these DEPs showed significant differences in their relative abundance across sexes in uninfected groups, strengthening their associations with the SIV/SHIV-infection status. Conclusion: Brain cortical LEVs proteome analyses revealed sex-specific prevalence of HIV-associated neuropathogenesis in SIV/SHIV-infected adult RMs. Funding support: NIH grants: R01NS136041(PKC), R56AG075988 (DWB), R21/R33AI110158 (SEB), and P51OD011104 (TNPRC). This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.