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Sonela N, Mann J, Godwe C, Goni OH, Tchakoute M, Nkoue N, de Oliveira T, Brockman MA, Brumme ZL, Ndung'u T, Tongo M. No detectable differences in Nef-mediated downregulation of HLA-I and CD4 molecules among HIV-1 group M lineages circulating in Cameroon, where the pandemic originated. FRONTIERS IN VIROLOGY (LAUSANNE, SWITZERLAND) 2024; 4:fviro.2024.1379217. [PMID: 38883214 PMCID: PMC7616105 DOI: 10.3389/fviro.2024.1379217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
HIV-1 group M (HIV-1M) lineages downregulate HLA-I and CD4 expression via their Nef proteins. We hypothesized that these Nef functions may be partially responsible for the differences in prevalence of viruses from different lineages that co-circulate within an epidemic. Here, we characterized these two Nef activities in HIV-1M isolates from Cameroon, where multiple variants have been circulating since the pandemic's origin. Single HIV-1 Nef clones from 234 HIV-1-ART naïve individuals living in remote villages and two cosmopolitan cities of Cameroon, sampled between 2000 and 2013, were isolated from plasma HIV RNA and analyzed for their capacity to downregulate HLA-I and CD4 molecules. We found that, despite a large degree of within- and inter- lineage variation, the ability of Nef to downregulate HLA-I was similar across these different viruses. Moreover, Nef-mediated CD4 downregulation activity was also well conserved across the different lineages found in Cameroon. In addition, we observed a trend towards higher HLA-I downregulation activity of viruses circulating in the cosmopolitan cities versus the remote villages, whereas the CD4 downregulation activities were similar across the two settings. Furthermore, we noted a significant decline of HLA-I downregulation activity from 2000 to 2013, providing additional evidence supporting the attenuation of the global HIV-1M population over time. Finally, we identified 18 amino acids associated with differential HLA-I downregulation and 13 amino acids associated with differential CD4 downregulation within the dominant CRF02_AG lineage. Our lack of observation of HIV lineage-related differences in Nef-mediated HLA-I and CD4 downregulation function suggests that these activities do not substantively influence the prevalence of different HIV-1M lineages in Cameroon.
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Affiliation(s)
- Nelson Sonela
- Center of Research for Emerging and Re-Emerging Diseases (CREMER), Institute of Medical Research and Study of Medicinal Plants (IMPM), Yaoundé, Cameroon
- Chantal BIYA International Reference Centre for Research on HIV/AIDS prevention and management (CIRCB), Yaoundé, Cameroon
- Department of Medicine, Weill Cornell Medical College, Cornell University, New York, NY, United States
| | - Jaclyn Mann
- HIV Pathogenesis Programme, University of KwaZulu-Natal, Durban, South Africa
| | - Celestin Godwe
- Center of Research for Emerging and Re-Emerging Diseases (CREMER), Institute of Medical Research and Study of Medicinal Plants (IMPM), Yaoundé, Cameroon
- Départment of Biochemistry, University of Douala, Douala, Cameroon
| | - Oumarou H Goni
- Center of Research for Emerging and Re-Emerging Diseases (CREMER), Institute of Medical Research and Study of Medicinal Plants (IMPM), Yaoundé, Cameroon
- Départment of Microbiology, Faculty of Sciences, University of Yaoundé 1, Yaoundé, Cameroon
| | - Mérime Tchakoute
- Programmes de Santé et développement au sein du Groupement de la Filière Bois du Cameroun, Yaoundé, Cameroon
| | - Nathalie Nkoue
- Programmes de Santé et développement au sein du Groupement de la Filière Bois du Cameroun, Yaoundé, Cameroon
| | - Tulio de Oliveira
- Centre for Epidemic Response and Innovation (CERI), School of Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), School of Laboratory Medicine and Medical Sciences, College of Health Sciences, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Mark A Brockman
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada
| | - Zabrina L Brumme
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada
| | - Thumbi Ndung'u
- HIV Pathogenesis Programme, University of KwaZulu-Natal, Durban, South Africa
- Max Planck Institute for Infection Biology, Berlin, Germany
- Africa Health Research Institute (AHRI), Durban, South Africa
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA, United States
- Division of Infection and Immunity, University College London, London, United Kingdom
| | - Marcel Tongo
- Center of Research for Emerging and Re-Emerging Diseases (CREMER), Institute of Medical Research and Study of Medicinal Plants (IMPM), Yaoundé, Cameroon
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Trifone C, Salido J, Ruiz MJ, Leng L, Quiroga MF, Salomón H, Bucala R, Ghiglione Y, Turk G. Interaction Between Macrophage Migration Inhibitory Factor and CD74 in Human Immunodeficiency Virus Type I Infected Primary Monocyte-Derived Macrophages Triggers the Production of Proinflammatory Mediators and Enhances Infection of Unactivated CD4 + T Cells. Front Immunol 2018; 9:1494. [PMID: 29997630 PMCID: PMC6030361 DOI: 10.3389/fimmu.2018.01494] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 06/15/2018] [Indexed: 11/13/2022] Open
Abstract
Understanding the mechanisms of human immunodeficiency virus type I (HIV-1) pathogenesis would facilitate the identification of new therapeutic targets to control the infection in face of current antiretroviral therapy limitations. CD74 membrane expression is upregulated in HIV-1-infected cells and the magnitude of its modulation correlates with immune hyperactivation in HIV-infected individuals. In addition, plasma level of the CD74 activating ligand macrophage migration inhibitory factor (MIF) is increased in infected subjects. However, the role played by MIF/CD74 interaction in HIV pathogenesis remains unexplored. Here, we studied the effect of MIF/CD74 interaction on primary HIV-infected monocyte-derived macrophages (MDMs) and its implications for HIV immunopathogenesis. Confocal immunofluorescence analysis of CD74 and CD44 (the MIF signal transduction co-receptor) expression indicated that both molecules colocalized at the plasma membrane specifically in wild-type HIV-infected MDMs. Treatment of infected MDMs with MIF resulted in an MIF-dependent increase in TLR4 expression. Similarly, there was a dose-dependent increase in the production of IL-6, IL-8, TNFα, IL-1β, and sICAM compared to the no-MIF condition, specifically from infected MDMs. Importantly, the effect observed on IL-6, IL-8, TNFα, and IL-1β was abrogated by impeding MIF interaction with CD74. Moreover, the use of a neutralizing αMIF antibody or an MIF antagonist reverted these effects, supporting the specificity of the results. Treatment of unactivated CD4+ T-cells with MIF-treated HIV-infected MDM-derived culture supernatants led to enhanced permissiveness to HIV-1 infection. This effect was lost when CD4+ T-cells were treated with supernatants derived from infected MDMs in which CD74/MIF interaction had been blocked. Moreover, the enhanced permissiveness of unactivated CD4+ T-cells was recapitulated by exogenous addition of IL-6, IL-8, IL-1β, and TNFα, or abrogated by neutralizing its biological activity using specific antibodies. Results obtained with BAL and NL4-3 HIV laboratory strains were reproduced using transmitted/founder primary isolates. This evidence indicated that MIF/CD74 interaction resulted in a higher production of proinflammatory cytokines from HIV-infected MDMs. This caused the generation of an inflammatory microenvironment which predisposed unactivated CD4+ T-cells to HIV-1 infection, which might contribute to viral spreading and reservoir seeding. Overall, these results support a novel role of the MIF/CD74 axis in HIV pathogenesis that deserves further investigation.
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Affiliation(s)
- César Trifone
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
| | - Jimena Salido
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
| | - María Julia Ruiz
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
| | - Lin Leng
- Department of Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - María Florencia Quiroga
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
| | - Horacio Salomón
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
| | - Richard Bucala
- Department of Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Yanina Ghiglione
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
| | - Gabriela Turk
- CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina
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Association between a naturally arising polymorphism within a functional region of HIV-1 Nef and disease progression in chronic HIV-1 infection. Arch Virol 2015; 160:2033-41. [PMID: 26060058 DOI: 10.1007/s00705-015-2480-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 05/31/2015] [Indexed: 01/24/2023]
Abstract
HIV-1 Nef mediates downregulation of HLA class I (HLA-I) through a number of highly conserved sequence motifs. We investigated the in vivo implication(s) of naturally arising polymorphisms in functional motifs in HIV-1 Nef that are associated with HLA-I downregulation, including the acidic cluster, polyproline, di-arginine and Met-20 regions. Plasma samples from treatment-naive, chronically HIV-1 infected subjects were collected after obtaining informed consent, and viral RNA was extracted and amplified by nested RT-PCR. The resultant nef amplicons were sequenced directly, and subtype-B sequences with an intact open reading frame (n = 406) were included in our analyses. There was over-representation of isoleucine at position 20 (Ile-20) in our dataset when compared to sequences in the Los Alamos sequence database (17.7 vs. 6.9 %, p = 0.0309). The presence of having Ile-20 in Nef was found to be associated with higher median plasma viral load (p = 0.013), independent of associated codons or viral lineage effects, whereas no clinical association was found with polymorphisms in the other functional motifs. Moreover, introduction of a Met-20-to-Ile mutation in a laboratory strain SF2 Nef resulted in a modest, albeit not statistically significant, increase in HLA class I downregulation activity (p = 0.06). Taken together, we have identified a naturally arising polymorphism, Ile-20, within HIV-1 subtype B Nef that is associated with poorer disease outcome.
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Turk G, Carobene MG. Deciphering How HIV-1 Intersubtype Recombination Shapes Viral Fitness and Disease Progression. EBioMedicine 2015; 2:188-9. [PMID: 26137559 PMCID: PMC4484815 DOI: 10.1016/j.ebiom.2015.02.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 02/16/2015] [Accepted: 02/16/2015] [Indexed: 01/30/2023] Open
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Koppensteiner H, Höhne K, Gondim MV, Gobert FX, Widder M, Gundlach S, Heigele A, Kirchhoff F, Winkler M, Benaroch P, Schindler M. Lentiviral Nef suppresses iron uptake in a strain specific manner through inhibition of Transferrin endocytosis. Retrovirology 2014; 11:1. [PMID: 24383984 PMCID: PMC3892060 DOI: 10.1186/1742-4690-11-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 12/20/2013] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Increased cellular iron levels are associated with high mortality in HIV-1 infection. Moreover iron is an important cofactor for viral replication, raising the question whether highly divergent lentiviruses actively modulate iron homeostasis. Here, we evaluated the effect on cellular iron uptake upon expression of the accessory protein Nef from different lentiviral strains. RESULTS Surface Transferrin receptor (TfR) levels are unaffected by Nef proteins of HIV-1 and its simian precursors but elevated in cells expressing Nefs from most other primate lentiviruses due to reduced TfR internalization. The SIV Nef-mediated reduction of TfR endocytosis is dependent on an N-terminal AP2 binding motif that is not required for downmodulation of CD4, CD28, CD3 or MHCI. Importantly, SIV Nef-induced inhibition of TfR endocytosis leads to the reduction of Transferrin uptake and intracellular iron concentration and is accompanied by attenuated lentiviral replication in macrophages. CONCLUSION Inhibition of Transferrin and thereby iron uptake by SIV Nef might limit viral replication in myeloid cells. Furthermore, this new SIV Nef function could represent a virus-host adaptation that evolved in natural SIV-infected monkeys.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Michael Schindler
- Institute of Virology, Helmholtz Zentrum Munich, German Research Center for Environmental Health, Neuherberg, Germany.
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Mann JK, Byakwaga H, Kuang XT, Le AQ, Brumme CJ, Mwimanzi P, Omarjee S, Martin E, Lee GQ, Baraki B, Danroth R, McCloskey R, Muzoora C, Bangsberg DR, Hunt PW, Goulder PJR, Walker BD, Harrigan PR, Martin JN, Ndung'u T, Brockman MA, Brumme ZL. Ability of HIV-1 Nef to downregulate CD4 and HLA class I differs among viral subtypes. Retrovirology 2013; 10:100. [PMID: 24041011 PMCID: PMC3849644 DOI: 10.1186/1742-4690-10-100] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Accepted: 09/09/2013] [Indexed: 11/29/2022] Open
Abstract
Background The highly genetically diverse HIV-1 group M subtypes may differ in their biological properties. Nef is an important mediator of viral pathogenicity; however, to date, a comprehensive inter-subtype comparison of Nef in vitro function has not been undertaken. Here, we investigate two of Nef’s most well-characterized activities, CD4 and HLA class I downregulation, for clones obtained from 360 chronic patients infected with HIV-1 subtypes A, B, C or D. Results Single HIV-1 plasma RNA Nef clones were obtained from N=360 antiretroviral-naïve, chronically infected patients from Africa and North America: 96 (subtype A), 93 (B), 85 (C), and 86 (D). Nef clones were expressed by transfection in an immortalized CD4+ T-cell line. CD4 and HLA class I surface levels were assessed by flow cytometry. Nef expression was verified by Western blot. Subset analyses and multivariable linear regression were used to adjust for differences in age, sex and clinical parameters between cohorts. Consensus HIV-1 subtype B and C Nef sequences were synthesized and functionally assessed. Exploratory sequence analyses were performed to identify potential genotypic correlates of Nef function. Subtype B Nef clones displayed marginally greater CD4 downregulation activity (p = 0.03) and markedly greater HLA class I downregulation activity (p < 0.0001) than clones from other subtypes. Subtype C Nefs displayed the lowest in vitro functionality. Inter-subtype differences in HLA class I downregulation remained statistically significant after controlling for differences in age, sex, and clinical parameters (p < 0.0001). The synthesized consensus subtype B Nef showed higher activities compared to consensus C Nef, which was most pronounced in cells expressing lower protein levels. Nef clones exhibited substantial inter-subtype diversity: cohort consensus residues differed at 25% of codons, while a similar proportion of codons exhibited substantial inter-subtype differences in major variant frequency. These amino acids, along with others identified in intra-subtype analyses, represent candidates for mediating inter-subtype differences in Nef function. Conclusions Results support a functional hierarchy of subtype B > A/D > C for Nef-mediated CD4 and HLA class I downregulation. The mechanisms underlying these differences and their relevance to HIV-1 pathogenicity merit further investigation.
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Affiliation(s)
- Jaclyn K Mann
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.
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Mann JK, Byakwaga H, Kuang XT, Le AQ, Brumme CJ, Mwimanzi P, Omarjee S, Martin E, Lee GQ, Baraki B, Danroth R, McCloskey R, Muzoora C, Bangsberg DR, Hunt PW, Goulder PJR, Walker BD, Harrigan PR, Martin JN, Ndung'u T, Brockman MA, Brumme ZL. Ability of HIV-1 Nef to downregulate CD4 and HLA class I differs among viral subtypes. Retrovirology 2013. [PMID: 24041011 DOI: 10.1186/742-4690-10-100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
BACKGROUND The highly genetically diverse HIV-1 group M subtypes may differ in their biological properties. Nef is an important mediator of viral pathogenicity; however, to date, a comprehensive inter-subtype comparison of Nef in vitro function has not been undertaken. Here, we investigate two of Nef's most well-characterized activities, CD4 and HLA class I downregulation, for clones obtained from 360 chronic patients infected with HIV-1 subtypes A, B, C or D. RESULTS Single HIV-1 plasma RNA Nef clones were obtained from N=360 antiretroviral-naïve, chronically infected patients from Africa and North America: 96 (subtype A), 93 (B), 85 (C), and 86 (D). Nef clones were expressed by transfection in an immortalized CD4+ T-cell line. CD4 and HLA class I surface levels were assessed by flow cytometry. Nef expression was verified by Western blot. Subset analyses and multivariable linear regression were used to adjust for differences in age, sex and clinical parameters between cohorts. Consensus HIV-1 subtype B and C Nef sequences were synthesized and functionally assessed. Exploratory sequence analyses were performed to identify potential genotypic correlates of Nef function. Subtype B Nef clones displayed marginally greater CD4 downregulation activity (p = 0.03) and markedly greater HLA class I downregulation activity (p < 0.0001) than clones from other subtypes. Subtype C Nefs displayed the lowest in vitro functionality. Inter-subtype differences in HLA class I downregulation remained statistically significant after controlling for differences in age, sex, and clinical parameters (p < 0.0001). The synthesized consensus subtype B Nef showed higher activities compared to consensus C Nef, which was most pronounced in cells expressing lower protein levels. Nef clones exhibited substantial inter-subtype diversity: cohort consensus residues differed at 25% of codons, while a similar proportion of codons exhibited substantial inter-subtype differences in major variant frequency. These amino acids, along with others identified in intra-subtype analyses, represent candidates for mediating inter-subtype differences in Nef function. CONCLUSIONS Results support a functional hierarchy of subtype B > A/D > C for Nef-mediated CD4 and HLA class I downregulation. The mechanisms underlying these differences and their relevance to HIV-1 pathogenicity merit further investigation.
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Affiliation(s)
- Jaclyn K Mann
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.
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Corró G, Rocco CA, De Candia C, Catano G, Turk G, Mangano A, Aulicino PC, Bologna R, Sen L. Genetic and functional analysis of HIV type 1 nef gene derived from long-term nonprogressor children: association of attenuated variants with slow progression to pediatric AIDS. AIDS Res Hum Retroviruses 2012; 28:1617-26. [PMID: 22583022 DOI: 10.1089/aid.2012.0020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Among persons infected by HIV-1, the rate of progression to AIDS is multifactorial being affected by host and viral factors, including the HIV-encoded negative factor (Nef). Our aim was to define whether variations in the nef gene as well as its functions may be associated with slower HIV disease course in infected children. The proviral HIV-1 nef gene was cloned, sequenced, and compared in children with contrasting disease course: 10 long-term nonprogressors (LTNP) and six rapid progressor (RP). The CD4 and MHC-I down-modulation ability of nef alleles derived from LTNP and RP children was analyzed. We observed that only one of our 10 LTNP had a protective genetic background, and out of them, 40% had defective nef genes, carrying substitutions at the (AWLEAQ(56-61)) and the (Rxx(22-24)) domains, and that those alleles were unable of down-regulate CD4 and MHC-I. The emergence or presence of Nef L58V substitution was associated with viral attenuation, indicated by a reduction in HIV viral loads, a persistent preservation of CD4(+) T cell counts, and lack of AIDS-related symptoms. Our results demonstrate that HIV-1 perinatally infected children carrying functionally defective nef HIV-1 strains have prolonged asymptomatic phases without therapy, suggesting a relevant role of CD4 and MHC-I down-modulation Nef domains on in vivo HIV-1 pathogenesis and pediatric immunodeficiency outcome.
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Affiliation(s)
- Guillermo Corró
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
| | - Carlos A Rocco
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
| | - Cristian De Candia
- National Reference Center for AIDS, University of Buenos Aires, Buenos Aires, Argentina
| | - Gabriel Catano
- Veterans Administration Research Center for AIDS and HIV-1 Infection, South Texas Veterans Health Care System and Department of Medicine, University of Texas Health Science Care at San Antonio, San Antonio, Texas
| | - Gabriela Turk
- National Reference Center for AIDS, University of Buenos Aires, Buenos Aires, Argentina
| | - Andrea Mangano
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
| | - Paula C. Aulicino
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
| | - Rosa Bologna
- Servicio de Infectología, Hospital de Pediatría “Prof. Dr. Juan P. Garrahan,” Buenos Aires, Argentina
| | - Luisa Sen
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
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A noncanonical mu-1A-binding motif in the N terminus of HIV-1 Nef determines its ability to downregulate major histocompatibility complex class I in T lymphocytes. J Virol 2012; 86:3944-51. [PMID: 22301137 DOI: 10.1128/jvi.06257-11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Downregulation of major histocompatibility complex class I (MHC-I) by HIV-1 Nef protein is indispensable for evasion of protective immunity by HIV-1. Though it has been suggested that the N-terminal region of Nef contributes to the function by associating with a mu-1A subunit of adaptor protein 1, the structural basis of the interaction between Nef and mu-1A remains elusive. We found that a tripartite hydrophobic motif (Trp13/Val16/Met20) in the N terminus of Nef was required for the MHC-I downregulation. Importantly, the motif functioned as a noncanonical mu-1A-binding motif for the interaction with the tyrosine motif-binding site of the mu-1A subunit. Our findings will help understanding of how HIV-1 evades the antiviral immune response by selectively redirecting the cellular protein trafficking system.
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Ghiglione Y, Rodríguez AM, De Candia C, Carobene M, Benaroch P, Schindler M, Salomón H, Turk G. HIV-mediated up-regulation of invariant chain (CD74) correlates with generalized immune activation in HIV+ subjects. Virus Res 2011; 163:380-4. [PMID: 21945129 DOI: 10.1016/j.virusres.2011.09.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/06/2011] [Accepted: 09/07/2011] [Indexed: 10/17/2022]
Abstract
HIV Nef-mediated up-regulation of invariant chain (Ii chain, also CD74) is presumed to play an active role in HIV immunopathogenesis. However, this has not been definitely ascertained. In order to help elucidate this hypothesis, Ii chain, CD4, HLA-DR and HLA-ABC expression was analyzed ex vivo in monocyte-derived macrophages (MDMs) from HIV(+) subjects. Viral load, CD4(+) T cell count and immune activation were also determined in enrolled subjects. Correlations between these parameters and the modulation of cell surface molecules in infected cells were studied. Ii chain expression was found to be up-regulated in infected MDMs derived from all patients but one (median fold up-regulation 2.47±1.82 (range 0.87-7.36)). Moreover, the magnitude of Ii chain up-regulation significantly correlated with higher activation of B and CD4(+) T cells (studied by HLA-DR and CD38 expression). On the other hand, lower HLA-ABC (i.e. stronger down-regulation) in infected MDMs was associated with higher CD4 counts. No correlation was observed between the magnitude of Ii chain up-regulation and the other Nef functions studied here. This is the first study reporting that Ii chain up-regulation occurs on naturally infected antigen presenting cells obtained directly from HIV(+) subjects. Moreover, it is also shown that the magnitude of this up-regulation correlates with immune activation. This allows postulating an alternative hypothesis regarding the contribution of Ii chain up-regulation to HIV-mediated immune damage.
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Affiliation(s)
- Yanina Ghiglione
- National Reference Center for AIDS, University of Buenos Aires, Buenos Aires, Argentina
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De Candia C, Espada C, Duette G, Ghiglione Y, Turk G, Salomón H, Carobene M. Viral replication is enhanced by an HIV-1 intersubtype recombination-derived Vpu protein. Virol J 2010; 7:259. [PMID: 20920359 PMCID: PMC2967538 DOI: 10.1186/1743-422x-7-259] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 10/04/2010] [Indexed: 01/02/2023] Open
Abstract
Background Multiple HIV-1 intersubtype recombinants have been identified in human populations. Previous studies from our lab group have shown that the epidemic in Argentina is characterized by the high prevalence of a circulating recombinant form, CRF12_BF, and many related BF recombinant forms. In these genomic structures a recombination breakpoint frequently involved the vpu coding region. Due to the scarce knowledge of Vpu participation in the virion release process and its impact on pathogenesis and of the functional capacities of intersubtype recombinant Vpu proteins, the aim of this work was to perform a comparative analysis on virion release capacity and relative replication capacity among viral variants harboring either a BF recombinant Vpu or a subtype B Vpu. Results Our results showed that BF recombinant Vpu was associated to an increased viral particles production when compared to WT B variant in tetherin-expressing cell lines. This observation was tested in the context of a competition assay between the above mentioned variants. The results showed that the replication of the BF Vpu-harboring variant was more efficient in cell cultures than subtype B, reaching a higher frequency in the viral population in a short period of time. Conclusion This study showed that as a result of intersubtype recombination, a structurally re-organized HIV-1 Vpu has an improved in vitro capacity of enhancing viral replication, and provides evidence of the changes occurring in this protein function that could play an important role in the successful spread of intersubtype recombinant variants.
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Affiliation(s)
- Cristian De Candia
- National Reference Center for AIDS, Department of Microbiology, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina
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Cavalieri E, Florido C, Leal É, Machado DM, Camargo M, Diaz RS, Janini LM. Intrahost and interhost variability of the HIV type 1 nef gene in Brazilian children. AIDS Res Hum Retroviruses 2009; 25:1129-40. [PMID: 19943790 DOI: 10.1089/aid.2009.0061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Many aspects of HIV-1 pathogenesis are affected by Nef protein activity, and efforts have been made to study variation in the nef gene and how that variation relates to disease outcome. We studied the genetic diversity of the nef gene in distinct clones obtained from the same patient (intrahost) and in sequences obtained from different hosts (interhost). The set of sequences analyzed was obtained from HIV-1-infected Brazilian children and contained 112 clones from 25 children (intrahost samples), as well as 55 sequences from epidemiologically unlinked children (interhost samples). We found extensive site polymorphisms and amino acid length variations, mainly in the amino terminal region of the nef gene, between the myristoylation motif (MGxxxS) and the MHC-1 downregulation motif (Rxx). Analysis of the sequences deposited in the Los Alamos HIV sequences database ( www.hiv.lanl.gov ) indicated that the most frequent motif at the MHC-1 downregulation site in the subtype B strain is R(86%)A(64%)E(82%) (n = 1040) and R(78%)T(74%)E(56%) in the subtype C strain (n = 549). Conversely, the Brazilian subtype B isolates presented the motif R(81%)T(62%)E(67%) at this site (n = 64). A detailed analysis of selective pressures identified a concentration of codons under strong positive selection in the amino terminal region of the nef gene. We also determined that different sites are under positive selection in the subtype B and subtype C viruses. The amino acid composition in the MHC-1 downregulation motif of the nef gene in our sequences may indicate a distinct adaptive pattern of HIV-1 subtype B to the Brazilian host population.
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Affiliation(s)
| | | | - Élcio Leal
- Federal University of São Paulo, São Paulo, Brazil
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Characterization of DNA and MVA vectors expressing Nef from HIV-1 CRF12_BF revealed high immune specificity with low cross-reactivity against subtype B. Virus Res 2009; 146:1-12. [PMID: 19715734 DOI: 10.1016/j.virusres.2009.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Revised: 08/06/2009] [Accepted: 08/20/2009] [Indexed: 11/20/2022]
Abstract
The HIV epidemic in Argentina is characterized by the high prevalence of infections caused by subtype B and BF variants. In this study, the Nef protein was used as a tool to study the impact of HIV-1 BF variants in the design of future vaccines. DNA and MVA vectors expressing Nef of the CRF12_BF recombinant form of HIV-1 were generated and characterized. After the administration of single DNAprime/MVAboost immunization schedules in Balb/c mice we found that NefBF delivered from these vectors generated a response of high specificity with low cross-reactivity against subtype B. But, when a more potent response was induced after 3 priming DNA doses and a booster with MVA virus, cross-reactivity against NefB was detected, although of lower magnitude than the NefBF specific. These results will be pivotal for vaccines designs in our region, indicating that antigens from these viral variants must be considered for a future vaccine.
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