Mapping Interaction Sites on Human Chemokine Receptors by Deep Mutational Scanning
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE100368 | GEO | 2018/04/23
REPOSITORIES: GEO
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Project description:The chemokine receptor CCR5 is a major co-receptor for human immunodeficiency virus 1 (HIV-1) mediating infection of target cells1,2. Beyond its function as co-receptor, CCR5 also influences the course of HIV disease and progression to AIDS3. However, it is unclear how CCR5 affects HIV-associated damage to the central nervous system (CNS) and development of HIV-associated neurocognitive disorders (HAND) independently of its co-receptor function. Here we show in a transgenic model of brain damage induced by HIV envelope protein gp1204 that genetic ablation of CCR5 prevents neuronal injury and loss and limits microglial activation, but fails to abrogate astrocytosis. CCR5 deficiency also protected gp120-transgenic mice against impairment of spatial learning and memory. Thus, CCR5-deficiency revealed that astrocytosis, a prominent pathological feature of AIDS brains5, can occur independently from neuronal demise and behavioral impairment. Since the viral envelope protein expressed in the transgenic mouse model originated from HIV-1 LAV4, a CXCR4-preferring virus that can infect macrophages6, CCR5 appeared to exert its control of neuronal injury predominantly in an indirect fashion and independently from its function as a co-receptor. Using analysis of genome-wide CNS gene expression we identified a subset of 734 genes that were differentially regulated in association with neuronal injury in the presence of CCR5. This subset of genes indicated that neuronal injury was associated with activation of macrophages and microglia. A set of 1305 genes was only differentially regulated in association with gp120 in the absence of CCR5 and indicated changes to leukocyte function and the anti-viral immune response besides a down-regulation of components in the GABAergic neurotransmission system. Interestingly, the most significantly differentially expressed genes were observed in a separate subset of 461 genes that was regulated in association with gp120 but independently of the CCR5 genotype. The finding that differential regulation of the 461 and 1305 gene sets was not necessarily linked to neuronal damage and loss suggested that altered expression of at least some of these factors may represent a protective adaptive response of the brain to the presence of viral gp120. Additional experiments using quantitative RT-PCR, protein assays and flow cytometry further supported the notion that CCR5 deficiency blunted microglial activation, a hallmark of HIV-associated brain injury7-9 without significantly affecting the expression of viral gp120. These results provide in vivo evidence for a significant role of CCR5 in HIV-associated CNS injury and behavioral impairment that is independent of the molecules’ function as HIV co-receptor. To characterize the neuroprotective effect of CCR5 ablation in the presence of HIV gp120, we next performed a genome-wide gene expression analysis using whole brain RNA preparations of mice from lines 1 and 2. We decided to collect samples from two time points before and after the ages of when we analyzed histopathology (6 months) and behavior (8 to 9 months) in order to identify genes for which differential regulation may be affected by an interaction of HIVgp120 expression and age. Accordingly, we collected brain tissue of gp120tg, CCR5KO x gp120tg, WT and CCR5KO mice at five different ages: 1.5, 3, 6, 12, and 20 (line 1) or 16 (line 2) months.
2014-09-09 | E-GEOD-47029 | biostudies-arrayexpress
Project description:The chemokine receptor CCR5 is a major co-receptor for human immunodeficiency virus 1 (HIV-1) mediating infection of target cells1,2. Beyond its function as co-receptor, CCR5 also influences the course of HIV disease and progression to AIDS3. However, it is unclear how CCR5 affects HIV-associated damage to the central nervous system (CNS) and development of HIV-associated neurocognitive disorders (HAND) independently of its co-receptor function. Here we show in a transgenic model of brain damage induced by HIV envelope protein gp1204 that genetic ablation of CCR5 prevents neuronal injury and loss and limits microglial activation, but fails to abrogate astrocytosis. CCR5 deficiency also protected gp120-transgenic mice against impairment of spatial learning and memory. Thus, CCR5-deficiency revealed that astrocytosis, a prominent pathological feature of AIDS brains5, can occur independently from neuronal demise and behavioral impairment. Since the viral envelope protein expressed in the transgenic mouse model originated from HIV-1 LAV4, a CXCR4-preferring virus that can infect macrophages6, CCR5 appeared to exert its control of neuronal injury predominantly in an indirect fashion and independently from its function as a co-receptor. Using analysis of genome-wide CNS gene expression we identified a subset of 734 genes that were differentially regulated in association with neuronal injury in the presence of CCR5. This subset of genes indicated that neuronal injury was associated with activation of macrophages and microglia. A set of 1305 genes was only differentially regulated in association with gp120 in the absence of CCR5 and indicated changes to leukocyte function and the anti-viral immune response besides a down-regulation of components in the GABAergic neurotransmission system. Interestingly, the most significantly differentially expressed genes were observed in a separate subset of 461 genes that was regulated in association with gp120 but independently of the CCR5 genotype. The finding that differential regulation of the 461 and 1305 gene sets was not necessarily linked to neuronal damage and loss suggested that altered expression of at least some of these factors may represent a protective adaptive response of the brain to the presence of viral gp120. Additional experiments using quantitative RT-PCR, protein assays and flow cytometry further supported the notion that CCR5 deficiency blunted microglial activation, a hallmark of HIV-associated brain injury7-9 without significantly affecting the expression of viral gp120. These results provide in vivo evidence for a significant role of CCR5 in HIV-associated CNS injury and behavioral impairment that is independent of the molecules’ function as HIV co-receptor.
2014-09-09 | GSE47029 | GEO
Project description:Fentanyl enhanced expression of CXCR4 and CCR5 protein levels and viral expression in a dose-dependent manner in multiple HIV-susceptible and HIV-infected cell lines. Multiple genes associated with apoptosis, antiviral / interferon response, chemokine. signaling, and NFκB signaling were differentially regulated by fentanyl. Thus fentanyl impacts HIV replication and chemokine co-receptor expression in HIV-susceptible and HIV-infected lymphocyte cell lines suggesting that opioid use may increase the likelihood of transmission to others and accelerate disease progression.
2022-10-20 | GSE216124 | GEO
Project description:HIV-1 infection begins with binding of the viral envelope glycoprotein Env to the host receptor CD4, triggering a series of conformational changes that lead to fusion of the virus and cell membranes. Env, a trimer of gp120 and gp41 subunits, occupies a ‘closed’ conformation with contacts between gp120 subunits at the apex, and transitions through an ‘open’ conformation with the gp120 subunits spread apart following CD4 binding. Using deep mutational scanning, sequence-fitness landscapes were mapped for full-length Env from the clade B BaL strain interacting with CD4, and broadly neutralizing antibodies VRC01 and PG16, which preferentially bind closed Env. Contacting residues are conserved for CD4 binding, and glycosylation at N262 is critical for accessing the high-affinity CD4-bound state. By comparison, VRC01 binding is resistant to most single amino acid substitutions, an ideal quality in a broadly neutralizing antibody. Also in contrast to CD4 interaction, Env interfacial residues are under tight selection for PG16 binding to maintain a closed conformation. Screening for mutations that enhanced PG16 binding, we identified several important sites, in particular neutralization of the electropositive apical cavity that we hypothesize promotes trimer opening by electrostatic repulsion. Mutations were combined to generate Quaternary Epitope Stabilized (QES) mutants with enhanced presentation of the PG16 epitope, and the mutations were partially transferable to other HIV-1 strains. These mutational analyses offer insight into Env conformational stabilization that may assist immunogen design.
2019-02-03 | GSE102276 | GEO
Project description:The illicit use of synthetic opioids such as fentanyl has led to a serious public health crisis in the United States. People with opioid use disorder are more likely to contract infections such as HIV and viral hepatitis. While several drugs of abuse are known to enhance viral replication and to suppress immunologic responses, the effects of synthetic opioids on HIV pathogenesis have not been investigated thoroughly. Thus, we examined the impact of fentanyl on HIV-susceptible and HIV-infected cell types and chemokine receptor expression in vitro. TZM-bl and HIV-infected lymphocyte cells were incubated with fentanyl at concentrations of 1 ng, 100 ng, and 10 ug. Expression levels of the CXCR4 and CCR5 chemokine receptors were measured in cell lysates, and HIV p24 antigen was quantified in culture supernatants by ELISA. HIV proviral DNA was quantified in cells using SYBR RT-PCR targeting the pol gene. Cell viability in the presence of drug was detected by the MTT Cell Proliferation Assay. RNA-seq and miRNAseq was performed to characterize cellular gene regulation in the presence of fentanyl. Fentanyl enhanced expression of CXCR4 and CCR5 protein levels in a dose-dependent manner in HIV-susceptible and HIV-infected cells. Similarly, fentanyl induced viral expression in HIV-exposed TZM-bl cells and in multiple HIV-infected lymphocyte cell lines. Multiple genes associated with apoptosis, antiviral / interferon response, chemokine signaling, and NFκB signaling were differentially regulated by fentanyl. These data demonstrate that the synthetic opioid fentanyl impacts HIV replication and chemokine co-receptor expression in HIV-susceptible and HIV-infected cells. Increased virus levels also suggest that opioid use may increase the likelihood of transmission to others and accelerate disease progression.
2022-10-19 | GSE216044 | GEO
Project description:Macrophages are important effector cells of the immune system and play an important role in mounting inflammatory responses. Macrophages can be activated by different stimuli in the tissue, either by cytokines produced by T helper cells (M1 or M2 polarization) or by the pathogens they encounter. Macrophages are also important target cells of HIV-1 and are preferentially infected by CCR5-using viruses. In this study, we investigated the ability of HIV-1 to induce changes in gene expression in unpolarized macrophages as well as in M1 or M2 polarized cells. We observed that CCR5-using HIV-1 regulates the expression of genes that are also regulated by IL-4 in macrophages. Genes regulated by HIV-1 infection and IL-4 polarization are involved in dampening pro-inflammatory responses in macrophages, which may facilitate HIV-1 to escape from detection by other immune cells. We also observed that changes in macrophage gene expression triggered by CCR5-using HIV-1 differed from those regulated by a CXCR4-using virus. This indicates that CCR5-using HIV-1 may be able to modulate macrophage gene expression to achieve successful replication. Our results provide insight in the complex interplay between HIV-1 and cells of the immune system. Polarized macrophages were obtained by stimulation of primary human monocytes with IFN-gamma (250 U/ml) in combination with TNF-alpha (12.5 ng/ml) (M1), IL-4 (50 ng/ml) (M2a), IL-10 (50 ng/ml) (M2c) for 5 days. Cells were inoculated for 24 hours with one of two HIV-1 strains (CCR5 or CXCR4 using HIV1) or their non replicating counterparts (heat inactivated virus). Macrophages that were not stimulated wiht cyokines or inoculates with HIV-1 were used as control. A total of 16 treatment conditions were tested in triplicate, for a total of 48 samples analysed.
2015-08-01 | E-GEOD-55029 | biostudies-arrayexpress
Project description:Many G protein-coupled receptors (GPCRs) are found to homo- or hetero-oligomerize, but how and why GPCRs associate remains controversial. The class A chemokine receptors CCR5 and CXCR4 both homo- and heterodimerize with each other, and crystal structures of CXCR4 in inactive conformations have captured dimeric organization. By selecting libraries of CCR5 and CXCR4 variants based on bimolecular fluorescence complementation, we determine how nearly every single amino acid substitution effects homo-associations. We find three mechanisms for chemokine receptor association: (i) non-specific aggregation in the membrane phase enhanced by destabilizing structural mutations, (ii) specific protein-protein dimerization interfaces, and (iii) motifs in the cytoplasmic tails that are hypothesized to promote lipid raft localization, thereby bringing receptors close together at high density. We identify mutations that tease apart the effects of these respective mechanisms, and show that specific dimer organization, despite reducing agonist binding, is necessary for active signaling within the cell.
2020-05-01 | GSE125426 | GEO
Project description:HIV-1 usually utilize CCR5 as the co-receptor and rarely switches to CXCR4-tropic until late stage of infection. CCR5+CD4+ T cells are the major virus-producing cells in patients as well as SIV-infected non-human primates. The differentiation of CCR5+CD4+ T cells is associated with the availability of IL-15, which increases during acute HIV-1 infection. Here, we report that CCR5 is expressed by CD4+ T cells exhibiting effector or effector memory phenotype with high expression levels of the IL-2/IL-15 receptor common beta and gamma chains. IL-15 but not IL-7 improves the survival of CCR5+CD4+ T cells, drives their expansion, and facilitates HIV-1 infection in vitro and in humanized mice. Our study suggests that IL-15 plays confounding roles in HIV-1 infection, and future studies on the IL-15-based boosting of anti-HIV-1 immunity should carefully exam the potential effects on the expansion of HIV-1 reservoirs in CCR5+CD4+ T cells.
2022-04-03 | GSE199729 | GEO
Project description:HIV-1 and HIV-2 are two etiological agents of Acquired Immune Deficiency Syndrome (AIDS). Several differences exist between these two retroviruses in terms of geographical distribution, replication, transmission and progression to AIDS. The molecular reasons explaining these features are largely unknown. One reason could rely on host factors able to differently counteract HIV replication. Among these factors, cellular microRNAs (miRNAs) have recently emerged as playing crucial roles. One aspect of the complex interplay between HIV and host miRNAs is the ability of HIV-1 to modulate host miRNAs and thereby to create favorable conditions for its replication. Here, we sought to compare the miRNA modulations elicited by HIV-1 and HIV-2 using an unbiased experimental strategy based on miRNA arrays. Surprisingly, we observed that these two unrelated HIVs similarly modulated the host miRNA repertoire, when utilizing CD4 and CXCR4 for entry. However, these modulations were different from the changes triggered by HIV-1 using CD4 and CCR5. In accordance with the mode of action of miRNAs, our observations were confirmed at the mRNA level. We concluded that co-receptor utilization (CXCR4 or CCR5), as opposed to genomic organization and phylogeny, is a key event determining the modulations of the host miRNA repertoire.
2012-03-06 | E-MEXP-3139 | biostudies-arrayexpress
Project description:<p>Rare individuals are highly resistant to infection with human immunodeficiency virus (HIV). Studies of candidate genes resulted in the discovery of a 32bp deletion in the CC-chemokine receptor 5 gene (CCR5Δ32), which rendered this critical co-receptor for primary HIV infection to be non-functional. Pharmacologic and vaccine-induced blockade of CCR5 is being pursued to treat and prevent HIV infection and other conditions.</p> <p>The allele frequency of CCR5Δ32 among persons of European ancestry is approximately 10%. CCR5Δ32/Δ32 homozygotes are almost totally resistant to HIV infection. People with severe hemophilia A require frequent replacement with clotting Factor VIII (FVIII) to control hemorrhage. Prior to the discovery of HIV in 1984 and licensure of recombinant FVIII in the late 1980s, people with severe hemophilia A were treated with plasma-derived FVIII and thus were intensively exposed to HIV. Only 5% of such patients were not infected with HIV. Of these, approximately 1/3 were CCR5Δ32/Δ32 homozygotes. The remaining 2/3 of these people who were highly resistant to HIV remain unexplained. This project seeks to discover genome variations among people who are highly resistant to HIV infection. Such variation is likely to serve as a target for reducing the morbidity and incidence of HIV. </p>
| phs000445 | dbGaP