miRNA profiling of primate cervicovaginal lavage and extracellular vesicles reveals miR-186-5p as a potential retroviral restriction factor in macrophages

Introduction: The goal of this study was to characterize extracellular vesicles (EVs) and miRNA profiles of primate cervicovaginal lavage (CVL) during the menstrual cycle and simian immunodeficiency virus (SIV) infection, and to determine if CVL-associated miRNAs might influence replication of retroviruses. Methods: CVL and peripheral blood were collected for five weeks from two uninfected and four SIV-infected macaques. EVs were enriched by stepped ultracentrifugation and characterized by population-level and single vesicle analyses. miRNA profiles were assessed with a medium-throughput stem-loop/hydrolysis probe qPCR platform and validated by targeted qPCR assays. Influence of miR-186-5p (miR-186) on HIV protein and RNA production was monitored in monocyte-derived macrophages. Results: Although menstrual hormone cycling was abnormal in infected subjects, EV concentration increased with progesterone in uninfected subjects. miRNAs were present predominantly in the EV-depleted supernatant fraction of CVL. Few changes in miRNA levels correlated with the menstrual cycle or SIV infection. miR-186, depleted in retroviral infection, was investigated for a possible role in controlling retroviral infection. miR-186 inhibited HIV production when transfected into monocyte-derived macrophages. Conclusions: We report profiles of a targeted set of miRNAs in CVL fractions. The menstrual cycle may affect quantity of EVs recovered from CVL, but has only minor effects on abundance of the miRNAs we examined. miR-186 decline appears to be associated with SIV infection, and miR-186 inhibits HIV replication in macrophages in vitro. Further studies are required to characterize the role of EVs and small RNAs as biomarkers of disease in the reproductive tract.