ABSTRACT: APOBEC3G and APOBEC3F are cell-encoded restriction factors that have evolved to counteract virus infections. When packaged into HIV-1 particles, A3G and A3F impair reverse transcription and induce the hypermutation of viral DNA. We employed a next generation sequencing approach to identify the RNAs that these proteins bind in HIV-1 infected cells and HIV-1 virions. We then analysed the mechanism of packaging of APOBEC3 in detail.
Project description:Critical cell surface immunoreceptors downregulated by HIV have previously been identified using non-systematic, candidate approaches. To gain a comprehensive, unbiased overview of how HIV infection remodels the T-cell surface, we took a distinct, systems-level, quantitative proteomic approach. HIV downregulated >100 plasma membrane proteins, many without characterised roles in the immune system. An exclusive group of host factors were targeted by the viral accessory proteins Vpu or Nef, including the amino acid transporter SNAT1 and the serine carriers SERINC3/5. We focussed on SNAT1, a novel, ß- TrCP-dependent Vpu substrate. Antagonism of SNAT1 emerges in Vpu variants from the lineage of SIVcpz/HIV-1 viruses responsible for pandemic AIDS. We found marked SNAT1 induction in activated primary human CD4+ T-cells, and used Consumption and Release (CoRe) metabolomics to identify alanine as an endogenous SNAT1 substrate required for T- cell mitogenesis. Downregulation of SNAT1 therefore defines a novel paradigm of viral interference with immunometabolism.
Project description:We have used RNA immunoprecipitation to identify the set of mRNAs that HIV-1 Tat interacts with in T-cells. We have also performed measurements of relative RNA abundance to determine if Tat binding is associated with an increase in RNA abundance in Tat-expressing T-cells and during HIV infection of primary T-cells. We have also used RNA IP and ChIP-Chip to compare the RNAs with which Tat interacts with to the RNAs that RISC interacts with and the genes associated with pTEF-b.
Project description:Herein expression trends of host miRNA were measured in HIV-1 latently infected and persistent replication cells, as well as the control cells. HIV-1 latency infection was established by infecting CEM-SS lymphocytes with HIV-1 Bru strain. After selection and long-term culture, the chronically infected cell showed the characteristics of latency definition: 1. The provirus was intergrated in to the host genome.2. No viral expression could be detected during culture.3 .Cell stimulators, such as TNFa,PMA, etc, reactivate the viral expression. As expected, miRNA trend was different in HIV-1 latency when compared to the control or HIV-1 replication. A subset of miRNAs is enriched in HIV-1 latency model. The observation reinforces the concept of active HIV-1 interplay with host small RNAs that modulate HIV-1 infection mode. In this study, the in vitro steady cell culture was used to explore the miRNA transcription signatures in HIV-1 infection. miRNA profiles were performed and compared among normal control,HIV-1 latency and HIV-1 replication .
Project description:Analysis of interferon-stimulated genes (ISGs) in various primary cells and immortalized cell lines, following type 1 interferon (IFN) treatment. Some cell types become resistant to HIV-1 infection following type 1 interferon treatment (such as macrophages, THP-1, PMA-THP-1, U87-MG cells and to a lesser extent, primary CD4+ T cells) while others either become only partially resistant (e.g., HT1080, PMA-U937) or remain permissive (e.g., CEM, CEM-SS, Jurkat T cell lines and U937); for more information see (Goujon and Malim, Journal of Virology 2010) and (Goujon and Schaller et al., Retrovirology 2013). We hypothesized that the anti-HIV-1 ISGs are differentially induced and expressed in restrictive cells compared to permissive cells and performed a whole genome analysis following type 1 IFN treatment in cell types exhibiting different HIV-1 resistance phenotypes. 48 samples; design: 9 cell lines, primary CD4+ T cells and primary macrophages, untreated and IFN-treated; 2 replicate experiments per cell line; 3 replicate experiments per primary cell type
Project description:Immune activation in people living with HIV on anti-retroviral therapy is associated with increased risk of morbidity and mortality, but the underlying mechanisms are poorly understood. To identify whether perturbation of immunological pathways persist at systems level, we compared genome-wide whole blood transcriptomes from 26 people living with HIV on long-term anti-retroviral therapy with 12 HIV-negative healthy controls. All participants were Caucasian male adults recruited from London, UK. People living with HIV were on anti-retroviral therapy for a median of 8.5 years (interquartile range 3-16 years). They had undetectable plasma HIV viral load (<40 copies/ml) and median circulating CD4 counts of 703 cells/µl (interquartile range 491-841 cells/µl).
Project description:HIV-1 Tat is a multifunctional protein, that in addition to its primary function of transactivating viral transcription also tends to modulate cellular gene expression, the molecular mechanism of which remains to be clearly elucidated. We have reported earlier NFκB enhancer binding activity of Tat and proposed its potential role in regulation of cellular gene expression. In the present study, we have analysed genome wide occupancy of Tat protein in HIV-1 infected cells. Our results identify an entire spectrum of binding sites of Tat protein on chromatin and also reveal that Tat is recruited majorly on gene promoters indicating its possible involvement in the regulation of cellular gene expression. Agilent two-color ChIP-on-Chip experiment, Organism: Homo sapiens ,Genotypic Technology designed Custom Human Promoter 244k ChIP-on-chip Array (AMADID-019469)
Project description:Early events of HIV-1 lifecycle, such as post-entry virus trafficking, uncoating and nuclear import, remain poorly understood due to limited information about virus-host interactions. We used a multidisciplinary approach. First, a mass spectrometry (MS)-based proteomics methodology enabled us to identify cellular proteins that specifically bind to 3-dimensional curved hexameric capsid lattices closely mimicking the assembled HIV-1 core. We then employed virology, live cell imaging, CRISPR gene knockout, x-ray crystallography, and biochemistry to demonstrate that Sec24C (a component of the COPII complex) is the first example of a cytoplasmic protein that utilizes an FG containing motif to directly and specifically bind the curved hexameric HIV-1 capsid lattices.
Project description:HIV-infected T cells secrete simultaneously viral particles and small extracellular vesicles (sEVs) including MVB-derived exosomes and plasma membrane-derived EVs. sEVs and HIV share many physical and chemical characteristics, which makes their separation difficult.. Here, we used a global and un-biased proteomic approach to identify novel specific markers of the virus or sEV subtypes secreted by a human T lymphoma cell line.
Project description:Exploratory microarray analysis identified significant changes in gene expression in adipose tissue. These included changes in genes regulating lipid and steroid metabolic processes and electron carrier activity in HIV-infected patients receiving antiretroviral therapy (ART). Additional genes involved in metabolic processes and mitochondrial function were found to be up-regulated in the adipose tissue of HIV-positive patients compared with HIV-negative controls. To identify differential gene expression in different tissues (PBMC, muscle, adipose tissue) between HIV patient groups (HIV negative, HIV positive with ART, HIV positive without ART).
Project description:We assessed correlates of protection from disease progression in a rare subset of HIV-infected individuals, viremic non-progressors (VNPs). These individuals have high viral load for several years, but in contrast to the majority of infected individuals, they do not progress to AIDS. Here we found this lack of progression was associated with selective preservation of two essential subsets of memory CD4+ T cells, central memory (TCM) and stem-cell memory (TSCM) cells. Compared to HIV-infected putative progressors, VNPs had higher proliferation of these indispensable subsets of memory cells, which was associated with the number of TCM. In addition, the long-lived CD4+ TCM and TSCM cells in VNPs had decreased HIV infection compared to the less critical effector memory CD4+ T cells, which indicates a possible mechanism by which VNPs maintain their CD4+ T cell pool after several years of infection, and remain free from AIDS progression. 6 HIV-infected patients fitting the clinical criteria of Viremic Non-Progressors were identified. VNPs were defined as having confirmed HIV-1 infection for at least 9 years with sustained plasma HIV RNA levels >10,000 copies/ml and maintenance of peripheral blood CD4+ T cell counts >500 cells/mm3 and a CD4% (of all lymphocytes) >15%. As controls, 7 HIV-infected Putative Progressors were identified. PPs were defined as having plasma HIV RNA levels >10,000 copies/mL, CD4+ T cell counts >400 cells/mm3 and having been initially infected with HIV 2-24 months prior to the index visit. The estimated date of initial HIV infection was calculated according to published algorithms that incorporate âde-tunedâ anti-HIV-1 antibody ELISA results or by a documented sero-conversion window of <6 months. All participants were required to be antiretroviral therapy (ART)-naïve. RNA from 6 VNP and 7 PPs was purified from PAXgene whole blood tubes and hybridized to Affymetrix U133 Plus 2.0 arrays. During data analysis, one VNP patient (PID 4015) was determined to be an outlier and removed from further analysis. Thus, 5 VNPs and 7 PPs are represented in this Series.