Date Published: March 12, 2018
Author(s): Samuel I. Anyanwu, Akins Doherty, Michael D. Powell, Chamberlain Obialo, Ming B. Huang, Alexander Quarshie, Claudette Mitchell, Khalid Bashir, Gale W. Newman.
Extracellular vesicles (EVs) are membrane bound, secreted by cells, and detected in bodily fluids, including urine, and contain proteins, RNA, and DNA. Our goal was to identify HIV and human proteins (HPs) in urinary EVs from HIV+ patients and compare them to HIV− samples.
Urine samples were collected from HIV+ (n = 35) and HIV− (n = 12) individuals. EVs were isolated by ultrafiltration and characterized using transmission electron microscopy, tandem mass spectrometry (LC/MS/MS), and nanoparticle tracking analysis (NTA). Western blots confirmed the presence of HIV proteins. Gene ontology (GO) analysis was performed using FunRich and HIV Human Interaction database (HHID).
EVs from urine were 30–400 nm in size. More EVs were in HIV+ patients, P < 0.05, by NTA. HIV+ samples had 14,475 HPs using LC/MS/MS, while only 111 were in HIV−. HPs in the EVs were of exosomal origin. LC/MS/MS showed all HIV+ samples contained at least one HIV protein. GO analysis showed differences in proteins between HIV+ and HIV− samples and more than 50% of the published HPs in the HHID interacted with EV HIV proteins. Differences in the proteomic profile of EVs from HIV+ versus HIV− samples were found. HIV and HPs in EVs could be used to detect infection and/or diagnose HIV disease syndromes.
Extracellular vesicles (EVs) are membrane bound vesicles, between 30 nm and 1 μm in size, are secreted into blood, urine, saliva, semen, and other bodily fluids, and have been suggested as a potential source of biomarkers for disease progression [1, 2]. These EVs, microparticles and/or exosomes, are secreted by cells normally or while they are undergoing stress or apoptosis  and contain proteins, mRNA, and miRNA  that are involved in cell to cell communication, transfer of antigens to cells, and intracellular communication. EVs are described in cancer disease pathogenesis  in HIV infection , other viral infections , and other disease states such as cardiovascular, renal, liver, and metabolic disease [8–11].
This is the first report of the detection of urinary EVs containing HIV and human proteins from HIV+ patients by mass spectrometry and western blot. EVs provide intercellular communication to cells through the delivery of their cargo, nucleic acids, miRNAs, and proteins, to recipient cells reviewed in . Previous studies have found EVs in plasma of HIV+ patients but did not describe HIV or human proteins within them. Others have described EVs containing HIV proteins but these results were from in vitro HIV infected cell cultures and not from HIV+ patients [18, 20, 22, 23, 36, 38–47]. This study details both the HIV and human proteins found in urinary EVs from HIV+ patients.