Human vaginal fluid contains exosomes that have an inhibitory effect on an early step of the HIV-1 life cycle

Smith, Johanna A.; Daniel, René

doi:10.1097/qad.0000000000001236

Cited by 52 publications

(42 citation statements)

References 24 publications

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“…In the context of HIV-1 infection, the source of exosomes dictates their role in HIV-1 infection (48). While exosomes produced from some HIV-1-infected cell lines may enhance viral infection, exosomes from body fluids, including breast milk, vaginal lavage fluid, and semen, inhibit HIV-1 infection (26,27,49,50). These diverse functions highlight the complexity associated with exosomes and their functions.…”

Section: Discussionmentioning

confidence: 99%

Semen Exosomes Promote Transcriptional Silencing of HIV-1 by Disrupting NF-κB/Sp1/Tat Circuitry

Welch

Kaddour

Schlievert

et al. 2018

J Virol

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Exosomes play various roles in host responses to cancer and infective agents, and semen exosomes (SE) inhibit HIV-1 infection and transmission, although the mechanism(s) by which this occurs is unclear. Here, we show that SE block HIV-1 proviral transcription at multiple transcriptional check points including transcription factor recruitment to the LTR, and transcription initiation and elongation. Biochemical and functional studies show that SE inhibit HIV-1 long terminal repeat (HIV-LTR)-driven viral gene expression and virus replication. Through partitioning of the HIV-1 RNA, we found that SE reduced the optimal expression of various viral RNA species. CHIP-RT-qPCR and EMSA analysis of infected cells identified human transcription factors NF-kB and Sp1, as well as RNA Pol II and the viral protein Tat as targets of SE. Of interest, SE inhibited HIV-1 LTR activation mediated by HIV-1 or Tat, but not by the mitogen PMA or TNFα. SE inhibited the DNA binding activities of NF-kB and Sp1 and blocked the recruitment of these transcription factors and Pol II to the HIV LTR promoter. Importantly, SE directly blocked NF-kB, Sp1, and Pol II binding to the LTR, and inhibited the interactions of Tat/NF-kB and Tat/Sp1, suggesting that SE-mediated inhibition of the functional quadripartite complex-NF-kB-Sp1-Pol II-Tat, may be a novel mechanism of proviral transcription repression. These data provide a novel molecular basis for SE-mediated inhibition of HIV-1 and identify Tat as a potential target of SE. HIV is most commonly transmitted sexually, and semen is the primary vector. Despite progress in studies of HIV pathogenesis and the success of combination antiretroviral therapy in controlling viral replication, current therapy cannot completely control sexual transmission. Thus, there is need for identifying effective methods of controlling HIV replication and transmission. Recently, it was shown that human semen contains exosomes that protect against HIV infection in vitro. In this study, we identified a mechanism by which semen exosomes inhibited HIV-1 RNA expression. We found that semen exosomes inhibit recruitment of transcription factors NF-kB and Sp1, as well as RNA Pol II to the promoter region in the 5' long terminal repeat (LTR) of HIV-1. The HIV-1 early protein, transcriptional activator (Tat) was a target of semen exosomes, and semen exosomes inhibited the binding and recruitment of Tat to the HIV-1 LTR.

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Section: Discussionmentioning

confidence: 99%

Semen Exosomes Promote Transcriptional Silencing of HIV-1 by Disrupting NF-κB/Sp1/Tat Circuitry

Welch

Kaddour

Schlievert

et al. 2018

J Virol

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“…While miRNAs have been profiled in cervicovaginal secretions and menstrual blood, mostly in the forensics setting [4,40,41], their associations with EV and exRNP fractions require further study. A recent publication reported that EVs from healthy vaginal secretions inhibited HIV-1 infection [29]. Another report found that CVL EVs (styled "exosomes") were present at higher concentrations in cervical cancer and that two miRNAs were also upregulated [5].…”

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confidence: 99%

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

et al. 2020

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Cervicovaginal secretions, or their components collected, are referred to as cervicovaginal lavage (CVL). CVL constituents have utility as biomarkers and play protective roles in wound healing and against HIV-1 infection. However, several components of cervicovaginal fluids are less well understood, such as extracellular RNAs and their carriers, for example, extracellular vesicles (EVs). EVs comprise a wide array of double-leaflet membrane extracellular particles and range in diameter from 30 nm to over one micron. The aim of this study was to determine whether differentially regulated CVL microRNAs (miRNAs) might influence retrovirus replication. To this end, we characterized EVs and miRNAs of primate CVL during the menstrual cycle and simian immunodeficiency virus (SIV) infection of macaques. EVs were enriched by stepped ultracentrifugation, and miRNA profiles were assessed with a medium-throughput stem-loop/hydrolysis probe qPCR platform. Whereas hormone cycling was abnormal in infected subjects, EV concentration correlated with progesterone concentration in uninfected subjects. miRNAs were present predominantly in the EVdepleted CVL supernatant. Only a small number of CVL miRNAs changed during the menstrual cycle or SIV infection, for example, miR-186-5p, which was depleted in retroviral infection. This miRNA inhibited HIV replication in infected macrophages in vitro. In silico target prediction and pathway enrichment analyses shed light on the probable functions of miR-186-5p in hindering HIV infections via immunoregulation, T-cell regulation, disruption of viral pathways, etc. These results provide further evidence for the potential of EVs and small RNAs as biomarkers or effectors of disease processes in the reproductive tract. The cervicovaginal canal is a potential source of biological markers for forensics investigations [1-4], reproductive tract cancers [5-7], and infections [8-10].

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“…For all experiments except RNA-Seq, the collected exosomes were further purified with anti-CD9 antibody-coated magnetic beads (CD9 Exo-Flow Exosome Purification Kit, System Biosciences, Cat. EXOTC10A-1) as in (Rim and Kim, 2016;Smith and Daniel, 2016).…”

Section: Collection and Purification Of Exosomes And Cd9-positive Exomentioning

confidence: 99%

Complexity and ultrastructure of infectious extracellular vesicles from cells infected by non-enveloped virus

Yang

Rossignol

Chang

et al. 2019

Preprint

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AbstractEnteroviruses support cell-to-cell viral transmission prior to their canonical lytic spread of virus. Poliovirus (PV), a prototype for human pathogenic positive-sense RNA enteroviruses, and picornaviruses in general, transport multiple virions en bloc via infectious extracellular vesicles secreted from host cells. Using biochemical and biophysical methods we identify multiple components in these secreted vesicles, including PV virions; positive and negative-sense viral RNA; essential viral replication proteins; ribosomal and regulatory cellular RNAs; and numerous host cell proteins, such as regulators of cellular metabolism and structural remodeling. Using cryo-electron tomography, we visualize the near-native three-dimensional architecture of secreted infectious extracellular vesicles containing both virions and a unique mat-like structure. Based on our biochemical data (western blot, RNA-Seq, and mass spectrometry), these mat-like structures are expected to be comprised of unencapsidated RNA and proteins. Our data show that, prior to cell lysis, non-enveloped viruses are secreted within infectious vesicles that also transport viral and host RNAs and proteins.ImportanceThe family of picornaviridae is comprised of small positive-sense RNA viruses, many of which are significant human pathogens. Picornaviruses exploit secreted extracellular vesicles for cell-to-cell viral transmission without cell lysis, and poliovirus serves as a model system for picornaviruses that are not protected by a surrounding membrane (non-enveloped viruses). The structure and contents of these vesicles secreted by virus-infected cells are described here. In addition to mature virions, these vesicles carry negative-sense, ‘template’ viral RNA and essential replication proteins, as well as cellular resources from the host. Their complex contents may comprise an enhanced virulence factor for propagation of infection, and understanding their structure and function is helping elucidate the mechanism by which extracellular vesicles contribute to the spread of non-enveloped virus infection.

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Human vaginal fluid contains exosomes that have an inhibitory effect on an early step of the HIV-1 life cycle

Cited by 52 publications

References 24 publications

Semen Exosomes Promote Transcriptional Silencing of HIV-1 by Disrupting NF-κB/Sp1/Tat Circuitry

Semen Exosomes Promote Transcriptional Silencing of HIV-1 by Disrupting NF-κB/Sp1/Tat Circuitry

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

Complexity and ultrastructure of infectious extracellular vesicles from cells infected by non-enveloped virus

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