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Xue D, Wei J, Lu W, Xia B, Li S, Liu D, Liu N, Wang X, Lin G. BDE-47 disturbs the immune response of lymphocytes to LPS by downregulating NF-κB pathway. CHEMOSPHERE 2022; 308:136562. [PMID: 36152834 DOI: 10.1016/j.chemosphere.2022.136562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 08/22/2022] [Accepted: 09/18/2022] [Indexed: 06/16/2023]
Abstract
The health risks associated with 2,2',4,4'-tetra-bromodiphenyl ether (BDE-47) have become an increasing concern due to its widespread presence in the environment and biological samples. To date, the potential toxicity of BDE-47 to immune system remains unclear. In this study, we aimed to study the immunotoxicity of BDE-47 using spleen-derived lymphocytes in vitro and BALB/c mice in vivo. In vitro results showed that lymphocytes exposed to 12.5-100 μM BDE-47 exhibited unchanged cell viability but decreased release of IL-6 and TNF-α when responding to lipopolysaccharide (LPS). The expression levels of p-p65, p-IκBα, TrkA and p-Akt involved in NF-κB pathway were obviously decreased, and NF-κB activator PMA could recover the BDE-47-induced inhibitory effect on IL-6 and TNF-α release by lymphocytes in response to LPS. In vivo data showed that BDE-47 orally administered to mice (1 mg/kg, 10 mg/kg, 100 mg/kg per day, 30 days) did not significantly affect body weight, organ index and histomorphology of spleen. However, ELISA assay showed that serum IL-6 and TNF-α levels from BDE-47-treated mice after intraperitoneal injection of LPS were significantly reduced, and high-throughput mouse cytokines screening found 13 more cytokines down-regulated in the serum. Transcriptomic sequencing of spleens identified 488 differential expressed genes (DEGs). GO enrichment analysis of these DEGs suggested that the GO term of response to LPS (GO: 0032,496) was significantly involved. KEGG enrichment analysis showed that the down-regulated DEGs significantly enriched in multiple immune-related signaling pathways including the NF-κB signaling pathway (mmu04064). Overall, these data suggested that BDE-47 could negatively regulate NF-κB signaling pathways to inhibit the immune response of lymphocytes to LPS, suggesting that exposures to BDE-47 may disturb the immune balance and increase the body's susceptibility to infectious diseases.
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Affiliation(s)
- Dahui Xue
- School of Public Health, Health Science Center, Shenzhen University, Shenzhen, 518071, China; School of Basic Medical Sciences, Health Science Center, Shenzhen University, Shenzhen, 518071, China
| | - Jinhua Wei
- School of Pharmacy, Health Science Center, Shenzhen University, Shenzhen, 518071, China
| | - Wencan Lu
- Department of Spine Surgery, Shenzhen University General Hospital, Shenzhen, 518055, China
| | - Beibei Xia
- School of Public Health, Health Science Center, Shenzhen University, Shenzhen, 518071, China; School of Basic Medical Sciences, Health Science Center, Shenzhen University, Shenzhen, 518071, China
| | - Shasha Li
- School of Public Health, Health Science Center, Shenzhen University, Shenzhen, 518071, China; School of Basic Medical Sciences, Health Science Center, Shenzhen University, Shenzhen, 518071, China
| | - Dongmeng Liu
- School of Basic Medical Sciences, Health Science Center, Shenzhen University, Shenzhen, 518071, China
| | - Nan Liu
- Institute of Environment and Health, South China Hospital, Health Science Center, Shenzhen University, Shenzhen, 518116, China
| | - Xiaomei Wang
- School of Basic Medical Sciences, Health Science Center, Shenzhen University, Shenzhen, 518071, China
| | - Guimiao Lin
- School of Public Health, Health Science Center, Shenzhen University, Shenzhen, 518071, China.
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2
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Evolution of CCR5 and CCR2 Genes in Bats Showed Multiple Independent Gene Conversion Events. Viruses 2022; 14:v14020169. [PMID: 35215768 PMCID: PMC8877049 DOI: 10.3390/v14020169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/12/2022] [Accepted: 01/15/2022] [Indexed: 11/16/2022] Open
Abstract
Chemokine receptors are an important determinant for the infectiousness of different pathogens, which are able to target the host cells by binding to the extracellular domains of these proteins. This is the mechanism of infection of HIV-1, among other concerning human diseases. Over the past years, it has been shown that two chemokine receptors, CCR2 and CCR5, have been shaped by events of gene conversion in different mammalian lineages, which has been linked to a possible selective advantage against pathogens. Here, by taking advantage of available bat genomes, we present the first insight of CCR2 and CCR5 evolution within the Chiroptera order. In total, four independent events of recombination between CCR2 and CCR5 were detected: two in a single species, Miniopterus natalensis; one in two species from the Rhinolophoidea superfamily; and one in four species from the Pteropodidae family. The regions affected by the gene conversions were generally extensive and always encompassed extracellular domains. Overall, we demonstrate that CCR2 and CCR5 have been subject to extensive gene conversion in multiple species of bats. Considering that bats are known to be large reservoirs of virus in nature, these results might indicate that chimeric CCR2-CCR5 genes might grant some bat species a selective advantage against viruses that rely in the extracellular portions of either CCR2 or CCR5 as gateways into the cell.
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3
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Zhao J, Song E, Huang Y, Yu A, Mechref Y. Variability in the Glycosylation Patterns of gp120 Proteins from Different Human Immunodeficiency Virus Type 1 Isolates Expressed in Different Host Cells. J Proteome Res 2021; 20:4862-4874. [PMID: 34448591 DOI: 10.1021/acs.jproteome.1c00587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The mature HIV-1 envelope (Env) glycoprotein is composed of gp120, the exterior subunit, and gp41, the transmembrane subunit assembled as trimer by noncovalent interaction. There is a great body of literature to prove that gp120 binds to CD4 first, then to the coreceptor. Binding experiments and functional assays have demonstrated that CD4 binding induces conformational changes in gp120 that enable or enhance its interaction with a coreceptor. Previous studies provided different glycomic maps for the HIV-1 gp120. Here, we build on previous work to report that the use of LC-MS/MS, in conjunction with hydrophilic interaction liquid chromatography (HILIC) enrichment to glycosylation sites, associated with the assorted neutralizing or binding events of glycosylation targeted antibodies from different clades or strains. In this study, the microheterogeneity of the glycosylation from 4 different clades of gp120s is deeply investigated. Aberrant glycosylation patterns were detected on gp120 that originated from different clades, viral sequences, and host cells. The results of this study may help provide a better understanding of the mechanism of how the glycans participate in the antibody neutralizing process that targets glycosylation sites.
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Affiliation(s)
- Jingfu Zhao
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Ehwang Song
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Yifan Huang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Aiying Yu
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Yehia Mechref
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
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4
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Al Bitar S, Ballouz T, Doughan S, Gali-Muhtasib H, Rizk N. Potential role of micro ribonucleic acids in screening for anal cancer in human papilloma virus and human immunodeficiency virus related malignancies. World J Gastrointest Pathophysiol 2021; 12:59-83. [PMID: 34354849 PMCID: PMC8316837 DOI: 10.4291/wjgp.v12.i4.59] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/24/2021] [Accepted: 05/19/2021] [Indexed: 02/06/2023] Open
Abstract
Despite advances in antiretroviral treatment (ART), human immunodeficiency virus (HIV) continues to be a major global public health issue owing to the increased mortality rates related to the prevalent oncogenic viruses among people living with HIV (PLWH). Human papillomavirus (HPV) is the most common sexually transmitted viral disease in both men and women worldwide. High-risk or oncogenic HPV types are associated with the development of HPV-related malignancies, including cervical, penile, and anal cancer, in addition to oral cancers. The incidence of anal squamous cell cancers is increasing among PLWH, necessitating the need for reliable screening methods in this population at risk. In fact, the currently used screening methods, including the Pap smear, are invasive and are neither sensitive nor specific. Investigators are interested in circulatory and tissue micro ribonucleic acids (miRNAs), as these small non-coding RNAs are ideal biomarkers for early detection and prognosis of cancer. Multiple miRNAs are deregulated during HIV and HPV infection and their deregulation contributes to the pathogenesis of disease. Here, we will review the molecular basis of HIV and HPV co-infections and focus on the pathogenesis and epidemiology of anal cancer in PLWH. The limitations of screening for anal cancer and the need for a reliable screening program that involves specific miRNAs with diagnostic and therapeutic values is also discussed.
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Affiliation(s)
- Samar Al Bitar
- Department of Biology, American University of Beirut, Beirut 1107 2020, Lebanon
| | - Tala Ballouz
- Department of Internal Medicine, American University of Beirut Medical Center, Beirut 1107 2020, Lebanon
| | - Samer Doughan
- Department of Surgery, American University of Beirut Medical Center, Beirut 1107 2020, Lebanon
| | - Hala Gali-Muhtasib
- Department of Biology and Center for Drug Discovery, American University of Beirut, Beirut 1107 2020, Lebanon
| | - Nesrine Rizk
- Department of Internal Medicine, American University of Beirut Medical Center, Beirut 1107 2020, Lebanon
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5
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Zuru DU. Theoretical model for the design and preparation of a CNT–ursonic acid drug matrix as HIV-gp120 entry inhibitor. SCIENTIFIC AFRICAN 2019. [DOI: 10.1016/j.sciaf.2019.e00177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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6
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Wetzel KS, Elliott STC, Collman RG. SIV Coreceptor Specificity in Natural and Non-Natural Host Infection: Implications for Cell Targeting and Differential Outcomes from Infection. Curr HIV Res 2019; 16:41-51. [PMID: 29173179 DOI: 10.2174/1570162x15666171124121805] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 07/07/2017] [Accepted: 07/07/2017] [Indexed: 11/22/2022]
Abstract
Pathogenic HIV-1 infection of humans and SIVmac infection of macaques are the result of zoonotic transfer of primate immunodeficiency viruses from their natural hosts into non-natural host species. Natural host infections do not result in pathogenesis despite high levels of virus replication, and evidence suggests that differences in anatomical location and specific subsets of CD4+ T cells infected may underlie distinct outcomes from infection. The coreceptor CCR5 has long been considered the sole pathway for SIV entry and the key determinant of CD4+ cell targeting, but it has also been known that natural hosts express exceedingly low levels of CCR5 despite maintaining high levels of virus replication. This review details emerging data indicating that in multiple natural host species, CCR5 is dispensable for SIV infection ex vivo and/or in vivo and, contrary to the established dogma, alternative coreceptors, particularly CXCR6, play a central role in infection and cell targeting. Infections of non-natural hosts, however, are characterized by CCR5-exclusive entry. These findings suggest that alternative coreceptor-mediated cell targeting in natural hosts, combined with low CCR5 expression, may direct the virus to distinct populations of cells that are dispensable for immune homeostasis, particularly extralymphoid and more differentiated CD4+ T cells. In contrast, CCR5-mediated entry in non-natural hosts results in targeting of CD4+ T cells that are located in lymphoid tissues, critical for immune homeostasis, or necessary for gut barrier integrity. Thus, fundamental differences in viral entry coreceptor use may be central determinants of infection outcome. These findings redefine the normal SIV/host relationship in natural host species, shed new light on key features linked to zoonotic immunodeficiency virus transfer, and highlight important questions regarding how and why this coreceptor bottleneck occurs and the coevolutionary equilibrium is lost following cross-species transfer that results in AIDS.
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Affiliation(s)
- Katherine S Wetzel
- Department of Medicine and Penn Center for AIDS Research, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Sarah T C Elliott
- Department of Medicine and Penn Center for AIDS Research, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Ronald G Collman
- Department of Medicine and Penn Center for AIDS Research, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
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7
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Falkenhagen A, Joshi S. HIV Entry and Its Inhibition by Bifunctional Antiviral Proteins. MOLECULAR THERAPY-NUCLEIC ACIDS 2018; 13:347-364. [PMID: 30340139 PMCID: PMC6197789 DOI: 10.1016/j.omtn.2018.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 09/05/2018] [Accepted: 09/05/2018] [Indexed: 12/14/2022]
Abstract
HIV entry is a highly specific and time-sensitive process that can be divided into receptor binding, coreceptor binding, and membrane fusion. Bifunctional antiviral proteins (bAVPs) exploit the multi-step nature of the HIV entry process by binding to two different extracellular targets. They are generated by expressing a fusion protein containing two entry inhibitors with a flexible linker. The resulting fusion proteins exhibit exceptional neutralization potency and broad cross-clade inhibition. In this review, we summarize the HIV entry process and provide an overview of the design, antiviral potency, and methods of delivery of bAVPs. Additionally, we discuss the advantages and limitations of bAVPs for HIV prevention and treatment.
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Affiliation(s)
- Alexander Falkenhagen
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 3E2, Canada
| | - Sadhna Joshi
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 3E2, Canada.
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8
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Wetzel KS, Yi Y, Yadav A, Bauer AM, Bello EA, Romero DC, Bibollet-Ruche F, Hahn BH, Paiardini M, Silvestri G, Peeters M, Collman RG. Loss of CXCR6 coreceptor usage characterizes pathogenic lentiviruses. PLoS Pathog 2018; 14:e1007003. [PMID: 29659623 PMCID: PMC5919676 DOI: 10.1371/journal.ppat.1007003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 04/26/2018] [Accepted: 04/02/2018] [Indexed: 11/18/2022] Open
Abstract
Pandemic HIV-1 originated from the cross-species transmission of SIVcpz, which infects chimpanzees, while SIVcpz itself emerged following the cross-species transmission and recombination of monkey SIVs, with env contributed by the SIVgsn/mus/mon lineage that infects greater spot-nosed, mustached and mona monkeys. SIVcpz and HIV-1 are pathogenic in their respective hosts, while the phenotype of their SIVgsn/mus/mon ancestors is unknown. However, two well-studied SIV infected natural hosts, sooty mangabeys (SMs) and African green monkeys (AGMs), typically remain healthy despite high viral loads; these species express low levels of the canonical coreceptor CCR5, and recent work shows that CXCR6 is a major coreceptor for SIV in these hosts. It is not known what coreceptors were used by the precursors of SIVcpz, whether coreceptor use changed during emergence of the SIVcpz/HIV-1 lineage, and what T cell subsets express CXCR6 in natural hosts. Using species-matched coreceptors and CD4, we show here that SIVcpz uses only CCR5 for entry and, like HIV-1, cannot use CXCR6. In contrast, SIVmus efficiently uses both CXCR6 and CCR5. Coreceptor selectivity was determined by Env, with CXCR6 use abrogated by Pro326 in the V3 crown, which is absent in monkey SIVs but highly conserved in SIVcpz/HIV-1. To characterize which cells express CXCR6, we generated a novel antibody that recognizes CXCR6 of multiple primate species. Testing lymphocytes from SM, the best-studied natural host, we found that CXCR6 is restricted to CD4+ effector memory cells, and is expressed by a sub-population distinct from those expressing CCR5. Thus, efficient CXCR6 use, previously identified in SM and AGM infection, also characterizes a member of the SIV lineage that gave rise to SIVcpz/HIV-1. Loss of CXCR6 usage by SIVcpz may have altered its cell tropism, shifting virus from CXCR6-expressing cells that may support replication without disrupting immune function or homeostasis, towards CCR5-expressing cells with pathogenic consequences.
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Affiliation(s)
- Katherine S. Wetzel
- Departments of Medicine and Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, United States of America
| | - Yanjie Yi
- Departments of Medicine and Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, United States of America
| | - Anjana Yadav
- Departments of Medicine and Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, United States of America
| | - Anya M. Bauer
- Departments of Medicine and Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, United States of America
| | - Ezekiel A. Bello
- Departments of Medicine and Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, United States of America
| | - Dino C. Romero
- Departments of Medicine and Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, United States of America
| | - Frederic Bibollet-Ruche
- Departments of Medicine and Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, United States of America
| | - Beatrice H. Hahn
- Departments of Medicine and Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, United States of America
| | - Mirko Paiardini
- Division of Microbiology and Immunology, Yerkes National Primate Research Center, Atlanta, GA, United States of America
| | - Guido Silvestri
- Division of Microbiology and Immunology, Yerkes National Primate Research Center, Atlanta, GA, United States of America
| | - Martine Peeters
- UMI233-TransVIHMI/INSERM U1175, Institut de Recherche pour le Développement (IRD) and University of Montpellier, Montpellier, France
| | - Ronald G. Collman
- Departments of Medicine and Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, United States of America
- * E-mail:
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9
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CXCR6-Mediated Simian Immunodeficiency Virus SIVagmSab Entry into Sabaeus African Green Monkey Lymphocytes Implicates Widespread Use of Non-CCR5 Pathways in Natural Host Infections. J Virol 2017; 91:JVI.01626-16. [PMID: 27903799 DOI: 10.1128/jvi.01626-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/22/2016] [Indexed: 12/14/2022] Open
Abstract
African green monkeys (AGM) and sooty mangabeys (SM) are well-studied natural hosts of simian immunodeficiency virus (SIV) that do not progress to AIDS when infected with their species-specific viruses. Natural hosts of SIV express very low levels of the canonical entry coreceptor CCR5, and recent studies have shown that CCR5 is dispensable for SIV infection of SM in vivo and that blocking of CCR5 does not prevent ex vivo infection of peripheral blood mononuclear cells (PBMC) from SM or vervet AGM. In both hosts, CXCR6 is an efficient entry pathway in vitro Here we investigated the use of species-matched CXCR6 and other alternative coreceptors by SIVagmSab, which infects sabaeus AGM. We cloned sabaeus CD4 and 10 candidate coreceptors. Species-matched CXCR6, CCR5, and GPR15 mediated robust entry into transfected cells by pseudotypes carrying SIVagmSab92018ivTF Env, with lower-level entry through GPR1 and APJ. We cloned genetically divergent env genes from the plasma of two wild-infected sabaeus AGM and found similar patterns of coreceptor use. Titration experiments showed that CXCR6 and CCR5 were more efficient than other coreceptors when tested at limiting CD4/coreceptor levels. Finally, blocking of CXCR6 with its ligand CXCL16 significantly inhibited SIVagmSab replication in sabaeus PBMC and had a greater impact than did the CCR5 blocker maraviroc, confirming the use of CXCR6 in primary lymphocyte infection. These data suggest a new paradigm for SIV infection of natural host species, whereby a shared outcome of virus-host coevolution is the use of CXCR6 or other alternative coreceptors for entry, which may direct SIV toward CD4+ T cell subsets and anatomical sites that support viral replication without disrupting immune homeostasis and function. IMPORTANCE Natural hosts of SIV do not progress to AIDS, in stark contrast to pathogenic human immunodeficiency virus type 1 (HIV-1)-human and SIVmac-macaque infections. Identifying how natural hosts avoid immunodeficiency can elucidate key mechanisms of pathogenesis. It is known that despite high viral loads, natural hosts have a low frequency of CD4+ cells expressing the SIV coreceptor CCR5. In this study, we demonstrate the efficient use of the coreceptor CXCR6 by SIVagmSab to infect sabaeus African green monkey lymphocytes. In conjunction with studies of SIVsmm, which infects sooty mangabeys, and SIVagmVer, which infects vervet monkeys, our data suggest a unifying model whereby in natural hosts, in which the CCR5 expression level is low, the use of CXCR6 or other coreceptors to mediate infection may target SIV toward distinct cell populations that are able to support high-level viral replication without causing a loss of CD4+ T cell homeostasis and lymphoid tissue damage that lead to AIDS in HIV-1 and SIVmac infections.
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10
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Kleist AB, Getschman AE, Ziarek JJ, Nevins AM, Gauthier PA, Chevigné A, Szpakowska M, Volkman BF. New paradigms in chemokine receptor signal transduction: Moving beyond the two-site model. Biochem Pharmacol 2016; 114:53-68. [PMID: 27106080 DOI: 10.1016/j.bcp.2016.04.007] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/13/2016] [Indexed: 10/21/2022]
Abstract
Chemokine receptor (CKR) signaling forms the basis of essential immune cellular functions, and dysregulated CKR signaling underpins numerous disease processes of the immune system and beyond. CKRs, which belong to the seven transmembrane domain receptor (7TMR) superfamily, initiate signaling upon binding of endogenous, secreted chemokine ligands. Chemokine-CKR interactions are traditionally described by a two-step/two-site mechanism, in which the CKR N-terminus recognizes the chemokine globular core (i.e. site 1 interaction), followed by activation when the unstructured chemokine N-terminus is inserted into the receptor TM bundle (i.e. site 2 interaction). Several recent studies challenge the structural independence of sites 1 and 2 by demonstrating physical and allosteric links between these supposedly separate sites. Others contest the functional independence of these sites, identifying nuanced roles for site 1 and other interactions in CKR activation. These developments emerge within a rapidly changing landscape in which CKR signaling is influenced by receptor PTMs, chemokine and CKR dimerization, and endogenous non-chemokine ligands. Simultaneous advances in the structural and functional characterization of 7TMR biased signaling have altered how we understand promiscuous chemokine-CKR interactions. In this review, we explore new paradigms in CKR signal transduction by considering studies that depict a more intricate architecture governing the consequences of chemokine-CKR interactions.
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Affiliation(s)
- Andrew B Kleist
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Anthony E Getschman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Joshua J Ziarek
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Ave, Boston, MA 02115, USA.
| | - Amanda M Nevins
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Pierre-Arnaud Gauthier
- Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg.
| | - Andy Chevigné
- Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg.
| | - Martyna Szpakowska
- Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg.
| | - Brian F Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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11
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Velasquez S, Malik S, Lutz SE, Scemes E, Eugenin EA. Pannexin1 Channels Are Required for Chemokine-Mediated Migration of CD4+ T Lymphocytes: Role in Inflammation and Experimental Autoimmune Encephalomyelitis. THE JOURNAL OF IMMUNOLOGY 2016; 196:4338-47. [PMID: 27076682 DOI: 10.4049/jimmunol.1502440] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 03/09/2016] [Indexed: 12/19/2022]
Abstract
Pannexin1 (Panx1) channels are large high conductance channels found in all vertebrates that can be activated under several physiological and pathological conditions. Our published data indicate that HIV infection results in the extended opening of Panx1 channels (5-60 min), allowing for the secretion of ATP through the channel pore with subsequent activation of purinergic receptors, which facilitates HIV entry and replication. In this article, we demonstrate that chemokines, which bind CCR5 and CXCR4, especially SDF-1α/CXCL12, result in a transient opening (peak at 5 min) of Panx1 channels found on CD4(+) T lymphocytes, which induces ATP secretion, focal adhesion kinase phosphorylation, cell polarization, and subsequent migration. Increased migration of immune cells is key for the pathogenesis of several inflammatory diseases including multiple sclerosis (MS). In this study, we show that genetic deletion of Panx1 reduces the number of the CD4(+) T lymphocytes migrating into the spinal cord of mice subjected to experimental autoimmune encephalomyelitis, an animal model of MS. Our results indicate that opening of Panx1 channels in response to chemokines is required for CD4(+) T lymphocyte migration, and we propose that targeting Panx1 channels could provide new potential therapeutic approaches to decrease the devastating effects of MS and other inflammatory diseases.
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Affiliation(s)
- Stephani Velasquez
- Public Health Research Institute, Rutgers New Jersey Medical School, Rutgers The State University of New Jersey, Newark, NJ 07103; Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers New Jersey Medical School, Rutgers The State University of New Jersey, Newark, NJ 07103
| | - Shaily Malik
- Public Health Research Institute, Rutgers New Jersey Medical School, Rutgers The State University of New Jersey, Newark, NJ 07103; Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers New Jersey Medical School, Rutgers The State University of New Jersey, Newark, NJ 07103
| | - Sarah E Lutz
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697; and
| | - Eliana Scemes
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Eliseo A Eugenin
- Public Health Research Institute, Rutgers New Jersey Medical School, Rutgers The State University of New Jersey, Newark, NJ 07103; Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers New Jersey Medical School, Rutgers The State University of New Jersey, Newark, NJ 07103;
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12
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Platt EJ, Durnin JP, Kabat D. Short Communication: HIV-1 Variants That Use Mouse CCR5 Reveal Critical Interactions of gp120's V3 Crown with CCR5 Extracellular Loop 1. AIDS Res Hum Retroviruses 2015; 31:992-8. [PMID: 26114311 PMCID: PMC4576943 DOI: 10.1089/aid.2015.0131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The CCR5 coreceptor amino terminus and extracellular (ECL) loops 1 and 2 have been implicated in HIV-1 infections, with species differences in these regions inhibiting zoonoses. Interactions of gp120 with CD4 and CCR5 reduce constraints on metastable envelope subunit gp41, enabling gp41 conformational changes needed for infection. We previously selected HIV-1JRCSF variants that efficiently use CCR5(Δ18) with a deleted amino terminus or CCR5(HHMH) with ECL2 from an NIH/Swiss mouse. Unexpectedly, the adaptive gp120 mutations were nearly identical, suggesting that they function by weakening gp120's grip on gp41 and/or by increasing interactions with ECL1. To analyze this and further wean HIV-1 from human CCR5, we selected variants using CCR5(HMMH) with murine ECL1 and 2 sequences. HIV-1JRCSF mutations adaptive for CCR5(Δ18) and CCR5(HHMH) were generally maladaptive for CCR5(HMMH), whereas the converse was true for CCR5(HMMH) adaptations. The HIV-1JRCSF variant adapted to CCR5(HMMH) also weakly used intact NIH/Swiss mouse CCR5. Our results strongly suggest that HIV-1JRCSF makes functionally critical contacts with human ECL1 and that adaptation to murine ECL1 requires multiple mutations in the crown of gp120's V3 loop.
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Affiliation(s)
- Emily J. Platt
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon
| | - James P. Durnin
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon
| | - David Kabat
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon
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13
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Vijayan A, García-Arriaza J, Raman SC, Conesa JJ, Chichón FJ, Santiago C, Sorzano CÓS, Carrascosa JL, Esteban M. A Chimeric HIV-1 gp120 Fused with Vaccinia Virus 14K (A27) Protein as an HIV Immunogen. PLoS One 2015. [PMID: 26208356 PMCID: PMC4514760 DOI: 10.1371/journal.pone.0133595] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the HIV vaccine field, there is a need to produce highly immunogenic forms of the Env protein with the capacity to trigger broad B and T-cell responses. Here, we report the generation and characterization of a chimeric HIV-1 gp120 protein (termed gp120-14K) by fusing gp120 from clade B with the vaccinia virus (VACV) 14K oligomeric protein (derived from A27L gene). Stable CHO cell lines expressing HIV-1 gp120-14K protein were generated and the protein purified was characterized by size exclusion chromatography, electron microscopy and binding to anti-Env antibodies. These approaches indicate that gp120-14K protein is oligomeric and reacts with a wide spectrum of HIV-1 neutralizing antibodies. Furthermore, in human monocyte-derived dendritic cells (moDCs), gp120-14K protein upregulates the levels of several proinflammatory cytokines and chemokines associated with Th1 innate immune responses (IL-1β, IFN-γ, IL-6, IL-8, IL-12, RANTES). Moreover, we showed in a murine model, that a heterologous prime/boost immunization protocol consisting of a DNA prime with a plasmid expressing gp120-14K protein followed by a boost with MVA-B [a recombinant modified vaccinia virus Ankara (MVA) expressing HIV-1 gp120, Gag, Pol and Nef antigens from clade B], generates stronger, more polyfunctional, and greater effector memory HIV-1-specific CD4+ and CD8+ T-cell immune responses, than immunization with DNA-gp120/MVA-B. The DNA/MVA protocol was superior to immunization with the combination of protein/MVA and the latter was superior to a prime/boost of MVA/MVA or protein/protein. In addition, these immunization protocols enhanced antibody responses against gp120 of the class IgG2a and IgG3, together favoring a Th1 humoral immune response. These results demonstrate that fusing HIV-1 gp120 with VACV 14K forms an oligomeric protein which is highly antigenic as it activates a Th1 innate immune response in human moDCs, and in vaccinated mice triggers polyfunctional HIV-1-specific adaptive and memory T-cell immune responses, as well as humoral responses. This novel HIV-1 gp120-14K immunogen might be considered as an HIV vaccine candidate for broad T and B-cell immune responses.
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Affiliation(s)
- Aneesh Vijayan
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
| | - Juan García-Arriaza
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
| | - Suresh C Raman
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
| | - José Javier Conesa
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
| | - Francisco Javier Chichón
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
| | - César Santiago
- X-ray Crystallization Unit, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
| | - Carlos Óscar S Sorzano
- Biocomputing Unit, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
| | - José L Carrascosa
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
| | - Mariano Esteban
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
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14
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Kufareva I, Salanga CL, Handel TM. Chemokine and chemokine receptor structure and interactions: implications for therapeutic strategies. Immunol Cell Biol 2015; 93:372-83. [PMID: 25708536 DOI: 10.1038/icb.2015.15] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 01/09/2015] [Accepted: 01/09/2015] [Indexed: 12/15/2022]
Abstract
The control of cell migration by chemokines involves interactions with two types of receptors: seven transmembrane chemokine-type G protein-coupled receptors and cell surface or extracellular matrix-associated glycosaminoglycans. Coordinated interaction of chemokines with both types of receptors is required for directional migration of cells in numerous physiological and pathological processes. Accumulated structural information, culminating most recently in the structure of a chemokine receptor in complex with a chemokine, has led to a view where chemokine oligomers bind to glycosaminoglycans through epitopes formed when chemokine subunits come together, while chemokine monomers bind to receptors in a pseudo two-step mechanism of receptor activation. Exploitation of this structural knowledge has and will continue to provide important information for therapeutic strategies, as described in this review.
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Affiliation(s)
- Irina Kufareva
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Catherina L Salanga
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Tracy M Handel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
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15
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Kramer VG, Hassounah S, Colby-Germinario SP, Oliveira M, Lefebvre E, Mesplède T, Wainberg MA. The dual CCR5 and CCR2 inhibitor cenicriviroc does not redistribute HIV into extracellular space: implications for plasma viral load and intracellular DNA decline. J Antimicrob Chemother 2014; 70:750-6. [PMID: 25433008 DOI: 10.1093/jac/dku451] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES Cenicriviroc is a potent antagonist of the chemokine coreceptors 5 and 2 (CCR5/CCR2) and blocks HIV-1 entry. The CCR5 inhibitor maraviroc has been shown in tissue culture to be able to repel cell-free virions from the cell surface into extracellular space. We hypothesized that cenicriviroc might exhibit a similar effect, and tested this using clinical samples from the Phase IIb study 652-2-202, by measuring rates of intracellular DNA decline. We also monitored viral RNA levels in culture fluids. METHODS We infected PM-1 cells with CCR5-tropic HIV-1 BaL in the presence or absence of inhibitory concentrations of cenicriviroc (20 nM) or maraviroc (50 nM) or controls. Viral load levels and p24 were measured by ELISA, quantitative PCR and quantitative real-time reverse transcription PCR at 4 h post-infection. Frozen PBMC DNA samples from 30 patients with virological success in the Phase IIb study were studied, as were early and late reverse transcript levels. Docking studies compared binding between cenicriviroc/CCR5 and maraviroc/CCR5. RESULTS Unlike maraviroc, cenicriviroc did not cause an increase in the amount of virus present in culture fluids at 4 h compared with baseline. The use of cenicriviroc did, however, result in lower levels of intracellular viral DNA after 4 h. Structural modelling indicates that cenicriviroc binds more deeply than maraviroc to the hydrophobic pocket of CCR5, providing an explanation for the absence of viral rebound with cenicriviroc. CONCLUSIONS In contrast to maraviroc, cenicriviroc does not repel virus back into extracellular space. Differences in results may be due to superior binding of cenicriviroc to CCR5 compared with maraviroc.
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Affiliation(s)
- Victor G Kramer
- McGill AIDS Centre, Lady Davis Institute, Jewish General Hospital, Montreal, QC, Canada Department of Experimental Medicine, McGill University, Montreal, QC, Canada
| | - Said Hassounah
- McGill AIDS Centre, Lady Davis Institute, Jewish General Hospital, Montreal, QC, Canada Department of Experimental Medicine, McGill University, Montreal, QC, Canada
| | | | - Maureen Oliveira
- McGill AIDS Centre, Lady Davis Institute, Jewish General Hospital, Montreal, QC, Canada
| | - Eric Lefebvre
- Tobira Therapeutics Inc., South San Francisco, CA, USA
| | - Thibault Mesplède
- McGill AIDS Centre, Lady Davis Institute, Jewish General Hospital, Montreal, QC, Canada
| | - Mark A Wainberg
- McGill AIDS Centre, Lady Davis Institute, Jewish General Hospital, Montreal, QC, Canada Department of Experimental Medicine, McGill University, Montreal, QC, Canada Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
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16
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Tamamis P, Floudas CA. Molecular recognition of CCR5 by an HIV-1 gp120 V3 loop. PLoS One 2014; 9:e95767. [PMID: 24763408 PMCID: PMC3999033 DOI: 10.1371/journal.pone.0095767] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 03/29/2014] [Indexed: 12/04/2022] Open
Abstract
The binding of protein HIV-1 gp120 to coreceptors CCR5 or CXCR4 is a key step of the HIV-1 entry to the host cell, and is predominantly mediated through the V3 loop fragment of HIV-1 gp120. In the present work, we delineate the molecular recognition of chemokine receptor CCR5 by a dual tropic HIV-1 gp120 V3 loop, using a comprehensive set of computational tools predominantly based on molecular dynamics simulations and free energy calculations. We report, what is to our knowledge, the first complete HIV-1 gp120 V3 loop : CCR5 complex structure, which includes the whole V3 loop and the N-terminus of CCR5, and exhibits exceptional agreement with previous experimental findings. The computationally derived structure sheds light into the functional role of HIV-1 gp120 V3 loop and CCR5 residues associated with the HIV-1 coreceptor activity, and provides insights into the HIV-1 coreceptor selectivity and the blocking mechanism of HIV-1 gp120 by maraviroc. By comparing the binding of the specific dual tropic HIV-1 gp120 V3 loop with CCR5 and CXCR4, we observe that the HIV-1 gp120 V3 loop residues 13-21, which include the tip, share nearly identical structural and energetic properties in complex with both coreceptors. This result paves the way for the design of dual CCR5/CXCR4 targeted peptides as novel potential anti-AIDS therapeutics.
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Affiliation(s)
- Phanourios Tamamis
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, United States of America
| | - Christodoulos A. Floudas
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, United States of America
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17
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Molecular recognition of CXCR4 by a dual tropic HIV-1 gp120 V3 loop. Biophys J 2014; 105:1502-14. [PMID: 24048002 DOI: 10.1016/j.bpj.2013.07.049] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 07/16/2013] [Accepted: 07/29/2013] [Indexed: 01/01/2023] Open
Abstract
HIV-1 cell entry is initiated by the interaction of the viral envelope glycoprotein gp120 with CD4, and chemokine coreceptors CXCR4 and CCR5. The molecular recognition of CXCR4 or CCR5 by the HIV-1 gp120 is mediated through the V3 loop, a fragment of gp120. The binding of the V3 loop to CXCR4 or CCR5 determines the cell tropism of HIV-1 and constitutes a key step before HIV-1 cell entry. Thus, elucidating the molecular recognition of CXCR4 by the V3 loop is important for understanding HIV-1 viral infectivity and tropism, and for the design of HIV-1 inhibitors. We employed a comprehensive set of computational tools, predominantly based on free energy calculations and molecular-dynamics simulations, to investigate the molecular recognition of CXCR4 by a dual tropic V3 loop. We report what is, to our knowledge, the first HIV-1 gp120 V3 loop:CXCR4 complex structure. The computationally derived structure reveals an abundance of polar and nonpolar intermolecular interactions contributing to the HIV-1 gp120:CXCR4 binding. Our results are in remarkable agreement with previous experimental findings. Therefore, this work sheds light on the functional role of HIV-1 gp120 V3 loop and CXCR4 residues associated with HIV-1 coreceptor activity.
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18
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Hashimoto C, Nomura W, Narumi T, Fujino M, Tsutsumi H, Haseyama M, Yamamoto N, Murakami T, Tamamura H. Anti-HIV-1 peptide derivatives based on the HIV-1 Co-receptor CXCR4. ChemMedChem 2013; 8:1668-72. [PMID: 24039179 DOI: 10.1002/cmdc.201300289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Indexed: 01/18/2023]
Abstract
The human immunodeficiency virus type 1 (HIV-1) uses CD4 and the co-receptor CCR5 or CXCR4 in the process of cell entry. The negatively charged extracellular domains of CXCR4 (CXCR4-ED) interact with positive charges on the V3 loop of gp120, facilitating binding via electrostatic interactions. The presence of highly conserved positively charged residues in the V3 loop suggests that CXCR4-ED-derived inhibitors might be broadly effective inhibitors. Synthetic peptide derivatives were evaluated for anti-HIV-1 activity. The 39-mer extracellular N-terminal region (NT) was divided into three fragments with 10-mer overlapping sites (N1-N3), and these linear peptides were synthesized. Peptide N1 contains Met 1-Asp 20 and shows significant anti-HIV-1 activity. Extracellular loops 1 and 2 (ECL1 and 2) were mimicked by cyclic peptides C1 and C2, which were synthesized by chemoselective cyclization. Cyclic peptides C1 and C2 show higher anti-HIV-1 activity than their linear peptide counterparts, L1 and L2. The cytotoxicities of C1 and C2 are lower than those of L1 and L2. These results indicate that Met 1-Asp 20 segments of the NT and cyclic peptides of ECL1 and ECL2 are potent anti-HIV-1 drug candidates.
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Affiliation(s)
- Chie Hashimoto
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kandasurugadai, Chiyoda-ku, Tokyo 101-0062 (Japan)
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19
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Li Y, Ye D. Molecular biology for formyl peptide receptors in human diseases. J Mol Med (Berl) 2013; 91:781-9. [PMID: 23404331 DOI: 10.1007/s00109-013-1005-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 01/21/2013] [Accepted: 01/27/2013] [Indexed: 02/07/2023]
Abstract
Leukocytes accumulate at sites of inflammation and immunological reaction in response to locally existing chemotactic mediators. The first chemotactic factors structurally defined were N-formyl peptides. Subsequently, numerous ligands were identified to activate formyl peptide receptors (FPRs) that belong to the seven-transmembrane G protein-coupled receptor superfamily. FPRs interact with this menagerie of structurally diverse pro- and anti-inflammatory ligands to possess important regulatory effects in multiple diseases, including inflammation, amyloidosis, Alzheimer's disease, prion disease, acquired immunodeficiency syndrome, obesity, diabetes, and cancer. How these receptors recognize diverse ligands and how they contribute to disease pathogenesis and host defense are basic questions currently under investigation that would open up new avenues for the future management of inflammation-related diseases.
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Affiliation(s)
- Yongsheng Li
- Department of Pathophysiology, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei 430030, China.
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20
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Zhukovsky MA, Lee PH, Ott A, Helms V. Putative cholesterol-binding sites in human immunodeficiency virus (HIV) coreceptors CXCR4 and CCR5. Proteins 2012; 81:555-67. [DOI: 10.1002/prot.24211] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 08/31/2012] [Accepted: 10/11/2012] [Indexed: 11/08/2022]
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21
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López de Victoria A, Tamamis P, Kieslich CA, Morikis D. Insights into the structure, correlated motions, and electrostatic properties of two HIV-1 gp120 V3 loops. PLoS One 2012; 7:e49925. [PMID: 23185486 PMCID: PMC3501474 DOI: 10.1371/journal.pone.0049925] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 10/15/2012] [Indexed: 12/11/2022] Open
Abstract
The V3 loop of the glycoprotein 120 (gp120) is a contact point for cell entry of HIV-1 leading to infection. Despite sequence variability and lack of specific structure, the highly flexible V3 loop possesses a well-defined role in recognizing and selecting cell-bound coreceptors CCR5 and CXCR4 through a mechanism of charge complementarity. We have performed two independent molecular dynamics (MD) simulations to gain insights into the dynamic character of two V3 loops with slightly different sequences, but significantly different starting crystallographic structures. We have identified highly populated trajectory-specific salt bridges between oppositely charged stem residues Arg9 and Glu25 or Asp29. The two trajectories share nearly identical correlated motions within the simulations, despite their different overall structures. High occupancy salt bridges play a key role in the major cross-correlated motions in both trajectories, and may be responsible for transient structural stability in preparation for coreceptor binding. In addition, the two V3 loops visit conformations with similarities in spatial distributions of electrostatic potentials, despite their inherent flexibility, which may play a role in coreceptor recognition. It is plausible that cooperativity between overall electrostatic potential, charged residue interactions, and correlated motions could be associated with a coreceptor selection and binding.
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Affiliation(s)
- Aliana López de Victoria
- Department of Bioengineering, University of California Riverside, Riverside, California, United States of America
| | - Phanourios Tamamis
- Department of Bioengineering, University of California Riverside, Riverside, California, United States of America
| | - Chris A. Kieslich
- Department of Bioengineering, University of California Riverside, Riverside, California, United States of America
| | - Dimitrios Morikis
- Department of Bioengineering, University of California Riverside, Riverside, California, United States of America
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22
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Perdomo MF, Sällberg M, Vahlne A. HIV inhibition by CD4 and CCR5-derived glycopeptides. AIDS Res Hum Retroviruses 2012; 28:1052-8. [PMID: 22559037 DOI: 10.1089/aid.2012.0009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
We have previously proposed a method by which natural antibodies can be redirected toward a known pathogen. We could show that CD4-derived peptides coupled to the galα1,3gal sugar moiety, a specificity held by natural antibodies, were able to neutralize HIV. Importantly, the antibody-peptide-antigen complexes activated the innate immune system through the Fc parts of the natural antibody. We now tested these peptides for their effectiveness on primary isolates and included sequence variations to increase their binding affinity. In addition, we evaluated three new CCR5-derived peptides. All peptides were tested for neutralization of six primary HIV-1 isolates. When testing three of the previously published glycopeptides we found that 10 to 100 times higher concentrations were needed to achieve the same neutralization of primary isolates. We found that the modifications of the CD4 glycopeptides modestly improved the neutralization of HIV-1. The modified CD4 and the CCR5 glycopeptides neutralized HIV-1 strains from different patients and of different subtypes. Notably, the combination of CD4 and CCR5 glycopeptides enhanced the neutralization potential as compared to the single peptides. A combination of CD4- and CCR5-galα1,3gal-linked peptides redirected natural antibodies to neutralize primary isolates of HIV-1, although less efficiently than laboratory-adapted strains. This might represent a new and valuable tool to block the entry of HIV into susceptible cells.
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Affiliation(s)
- Maria F. Perdomo
- Division of Clinical Microbiology, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
| | - Matti Sällberg
- Division of Clinical Microbiology, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
| | - Anders Vahlne
- Division of Clinical Microbiology, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
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23
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Möbius K, Dürr R, Haußner C, Dietrich U, Eichler J. A Functionally Selective Synthetic Mimic of the HIV‐1 Co‐receptor CXCR4. Chemistry 2012; 18:8292-5. [DOI: 10.1002/chem.201200111] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/15/2012] [Indexed: 01/21/2023]
Affiliation(s)
- Kalle Möbius
- Department Chemistry and Pharmacy, Universität Erlangen‐Nürnberg, Schuhstrasse 19, 91052 Erlangen (Germany), Fax: (+49) 9131‐8522587
| | - Ralf Dürr
- Georg‐Speyer‐Haus—Institute of Biomedical Research, Paul‐Ehrlich‐Str. 42–44, 60596 Frankfurt (Germany)
| | - Christina Haußner
- Department Chemistry and Pharmacy, Universität Erlangen‐Nürnberg, Schuhstrasse 19, 91052 Erlangen (Germany), Fax: (+49) 9131‐8522587
| | - Ursula Dietrich
- Georg‐Speyer‐Haus—Institute of Biomedical Research, Paul‐Ehrlich‐Str. 42–44, 60596 Frankfurt (Germany)
| | - Jutta Eichler
- Department Chemistry and Pharmacy, Universität Erlangen‐Nürnberg, Schuhstrasse 19, 91052 Erlangen (Germany), Fax: (+49) 9131‐8522587
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24
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Connell BJ, Baleux F, Coic YM, Clayette P, Bonnaffé D, Lortat-Jacob H. A synthetic heparan sulfate-mimetic peptide conjugated to a mini CD4 displays very high anti- HIV-1 activity independently of coreceptor usage. ACTA ACUST UNITED AC 2012; 19:131-9. [PMID: 22284360 DOI: 10.1016/j.chembiol.2011.12.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 11/30/2011] [Accepted: 12/12/2011] [Indexed: 12/01/2022]
Abstract
The HIV-1 envelope gp120, which features both the virus receptor (CD4) and coreceptor (CCR5/CXCR4) binding sites, offers multiple sites for therapeutic intervention. However, the latter becomes exposed, thus vulnerable to inhibition, only transiently when the virus has already bound cellular CD4. To pierce this defense mechanism, we engineered a series of heparan sulfate mimicking tridecapeptides and showed that one of them target the gp120 coreceptor binding site with μM affinity. Covalently linked to a CD4-mimetic that binds to gp120 and renders the coreceptor binding domain available to be targeted, the conjugated tridecapeptide now displays nanomolar affinity for its target. Using solubilized coreceptors captured on top of sensorchip we show that it inhibits gp120 binding to both CCR5 and CXCR4 and in peripheral blood mononuclear cells broadly inhibits HIV-1 replication with an IC(50) of 1 nM.
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Affiliation(s)
- Bridgette Janine Connell
- CEA, CNRS, Université Joseph Fourier - Grenoble 1, Institut de Biologie Structurale Jean-Pierre Ebel, UMR 5075, 38000 Grenoble, France
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25
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Espirito-Santo M, Santos-Costa Q, Calado M, Dorr P, Azevedo-Pereira JM. Susceptibility of HIV type 2 primary isolates to CCR5 and CXCR4 monoclonal antibodies, ligands, and small molecule inhibitors. AIDS Res Hum Retroviruses 2012; 28:478-85. [PMID: 21902586 DOI: 10.1089/aid.2011.0124] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Human immunodeficiency virus (HIV) entry into susceptible cells involves the interaction between viral envelope glycoproteins with CD4 and a chemokine receptor (coreceptor), namely CCR5 and CXCR4. This interaction has been studied to enable the discovery of a new class of antiretroviral drugs that targets the envelope glycoprotein-coreceptor interaction. However, very few data exist regarding HIV-2 susceptibility to these coreceptor inhibitors. With this work we aimed to identify this susceptibility in order to assess the potential use of these molecules to treat HIV-2-infected patients and to further understand the molecular basis of HIV-2 envelope glycoprotein interactions with CCR5 and CXCR4. We found that CCR5-using HIV-2 isolates are readily inhibited by maraviroc, TAK-779, and PF-227153, while monoclonal antibody 2D7 shows only residual or no inhibitory effects. The anti-HIV-2 activity of CXCR4-targeted molecules reveals that SDF-1α/CXCL12 inhibited all HIV-2 tested except one, while mAb 12G5 inhibited the replication of only two isolates, showing residual inhibitory effects with all the other CXCR4-using viruses. A major conclusion from our results is that infection by HIV-2 primary isolates is readily blocked in vitro by maraviroc, at concentrations similar to those required for HIV-1. The susceptibility to maraviroc was independent of CD4(+) T cell counts or clinical stage of the patient from which the virus was obtained. These findings indicate that maraviroc could constitute a reliable therapeutic alternative for HIV-2-infected patients, as long as they are infected with CCR5-using variants, and this may have direct implications for the clinical management of HIV-2-infected patients.
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Affiliation(s)
- Maria Espirito-Santo
- Centro de Patogénese Molecular, Unidade de Retrovírus e Infecções Associadas, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, Lisbon, Portugal
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26
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Delhalle S, Schmit JC, Chevigné A. Phages and HIV-1: from display to interplay. Int J Mol Sci 2012; 13:4727-4794. [PMID: 22606007 PMCID: PMC3344243 DOI: 10.3390/ijms13044727] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 03/26/2012] [Accepted: 03/30/2012] [Indexed: 11/16/2022] Open
Abstract
The complex hide-and-seek game between HIV-1 and the host immune system has impaired the development of an efficient vaccine. In addition, the high variability of the virus impedes the long-term control of viral replication by small antiviral drugs. For more than 20 years, phage display technology has been intensively used in the field of HIV-1 to explore the epitope landscape recognized by monoclonal and polyclonal HIV-1-specific antibodies, thereby providing precious data about immunodominant and neutralizing epitopes. In parallel, biopanning experiments with various combinatorial or antibody fragment libraries were conducted on viral targets as well as host receptors to identify HIV-1 inhibitors. Besides these applications, phage display technology has been applied to characterize the enzymatic specificity of the HIV-1 protease. Phage particles also represent valuable alternative carriers displaying various HIV-1 antigens to the immune system and eliciting antiviral responses. This review presents and summarizes the different studies conducted with regard to the nature of phage libraries, target display mode and biopanning procedures.
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Affiliation(s)
- Sylvie Delhalle
- Laboratory of Retrovirology, CRP-Sante, 84, Val Fleuri, L-1526 Luxembourg, Luxembourg; E-Mails: (J.-C.S.); (A.C.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +352-26970211; Fax: +352-26970221
| | - Jean-Claude Schmit
- Laboratory of Retrovirology, CRP-Sante, 84, Val Fleuri, L-1526 Luxembourg, Luxembourg; E-Mails: (J.-C.S.); (A.C.)
- Service National des Maladies Infectieuses, Centre Hospitalier Luxembourg, 4, rue E. Barblé, L-1210 Luxembourg, Luxembourg
| | - Andy Chevigné
- Laboratory of Retrovirology, CRP-Sante, 84, Val Fleuri, L-1526 Luxembourg, Luxembourg; E-Mails: (J.-C.S.); (A.C.)
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27
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Abstract
The G protein-coupled receptor of human chemokine receptor 5 (CCR5) is a key target in the human immunodeficiency virus (HIV) infection process due to its major involvement in binding to the HIV type 1 (HIV-1) envelope glycoprotein gp120 and facilitating virus entry into the cells. The identification of naturally occurring CCR5 mutations (especially CCR5 delta-32) has allowed us to address the CCR5 molecule as a promising target to prevent or resist HIV infection in vivo. To obtain high-affinity peptides that can be used to block CCR5, CCR5 analogs with high conformational similarity are required. In this study, two recombinant proteins named CCR5 N-Linker-E2 and CCR5 mN-E1-E2 containing the fragments of the CCR5 N-terminal, the first extracellular loop or the second extracellular loop are cloned from a full-length human CCR5 cDNA. The recombinant human CCR5 analogs with self-cleavage activity of the intein Mxe or Ssp in the vector pTwinI were then produced with a high-yield expression and purification system in Escherichia coli. Experiments of extracellular epitope-activity identification (such as immunoprecipitation and indirective/competitive enzyme-linked immunosorbent assay) confirmed the close similarity between the epitope activity of the CCR5 analogs and that of the natural CCR5, suggesting the applicability of the recombinant CCR5 analogs as antagonists of the chemokine ligands. Subsequent screening of high-affinity peptides from the phage random-peptides library acquired nine polypeptides, which could be used as CCR5 peptide antagonists. The CCR5 analogs and affinity peptides elucidated in this paper provide us with a basis for further study of the mechanism of inhibition of HIV-1 infection.
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Affiliation(s)
- Yingping Wu
- Biopharmaceutical Centre, State Key Laboratory of Biocontrol, College of Life Sciences, Sun Yat-Sen University, Guangdong 510275, China
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Jiménez JL, Pion M, Mata FJDL, Gomez R, Muñoz E, Leal M, Muñoz-Fernandez MA. Dendrimers as topical microbicides with activity against HIV. NEW J CHEM 2012. [DOI: 10.1039/c1nj20396g] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Cloning and analysis of sooty mangabey alternative coreceptors that support simian immunodeficiency virus SIVsmm entry independently of CCR5. J Virol 2011; 86:898-908. [PMID: 22090107 DOI: 10.1128/jvi.06415-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Natural host sooty mangabeys (SM) infected with simian immunodeficiency virus SIVsmm do not develop AIDS despite high viremia. SM and other natural hosts express very low levels of CCR5 on CD4(+) T cells, and we recently showed that SIVsmm infection and robust replication occur in vivo in SM genetically lacking CCR5, indicating the use of additional entry pathways. SIVsmm uses several alternative coreceptors of human origin in vitro, but which molecules of SM origin support entry is unknown. We cloned a panel of putative coreceptors from SM and tested their ability to mediate infection, in conjunction with smCD4, by pseudotypes carrying Envs from multiple SIVsmm subtypes. smCXCR6 supported efficient infection by all SIVsmm isolates with entry levels comparable to those for smCCR5, and smGPR15 enabled entry by all isolates at modest levels. smGPR1 and smAPJ supported low and variable entry, whereas smCCR2b, smCCR3, smCCR4, smCCR8, and smCXCR4 were not used by most isolates. In contrast, SIVsmm from rare infected SM with profound CD4(+) T cell loss, previously reported to have expanded use of human coreceptors, including CXCR4, used smCXCR4, smCXCR6, and smCCR5 efficiently and also exhibited robust entry through smCCR3, smCCR8, smGPR1, smGPR15, and smAPJ. Entry was similar with both known alleles of smCD4. These alternative coreceptors, particularly smCXCR6 and smGPR15, may support virus replication in SM that have restricted CCR5 expression as well as SM genetically lacking CCR5. Defining expression of these molecules on SM CD4(+) subsets may delineate distinct natural host target cell populations capable of supporting SIVsmm replication without CD4(+) T cell loss.
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30
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Wang FY, He SY, Zhang ZJ, He LF, Chen XW, Teng T. Analyses of anti-HIV type 1 activity of a small CCR5 peptide antagonist. AIDS Res Hum Retroviruses 2011; 27:1111-5. [PMID: 21375388 DOI: 10.1089/aid.2010.0303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We have identified a small peptide (AFDWTFVPSLIL) that specifically binds to CC chemokine receptor 5 (CCR5) expressed on the Chinese hamster ovary (CHO) cell surface. Here, we further investigate its interaction with CCR5 on activated peripheral blood mononuclear cells (PBMCs), and determine whether the peptide inhibits HIV-1 infection mediated by CCR5 in PBMCs. The peptide antagonized the binding of CCR5 ligands, the second extracellular loop-specific monoclonal antibody (mAb) (2D7), regulated on activation of normal expressed and secreted T cells (RANTES), to PBMCs and blocked CCR5-mediated Ca(2+) signaling elicited by RANTES at a concentration of 10 μg/ml. Moreover, the peptide displayed selective inhibition of R5 HIV-1 replication. We conclude that the peptide is a CCR5 antagonist with anti-HIV-1 activity.
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Affiliation(s)
- Fang Yu Wang
- Department of Life Science, The Key Laboratory of Functional Organometallic Materials of Hunan Province, Hengyang Normal University, Hengyang, People's Republic of China
- School of Pharmaceutical and Life Science, University of South China, Hengyang, People's Republic of China
| | - Shu Ya He
- School of Pharmaceutical and Life Science, University of South China, Hengyang, People's Republic of China
| | - Zhi Jian Zhang
- Department of Life Science, The Key Laboratory of Functional Organometallic Materials of Hunan Province, Hengyang Normal University, Hengyang, People's Republic of China
| | - Li Fang He
- Department of Life Science, The Key Laboratory of Functional Organometallic Materials of Hunan Province, Hengyang Normal University, Hengyang, People's Republic of China
| | - Xiao Wei Chen
- School of Pharmaceutical and Life Science, University of South China, Hengyang, People's Republic of China
| | - Tao Teng
- Department of Life Science, The Key Laboratory of Functional Organometallic Materials of Hunan Province, Hengyang Normal University, Hengyang, People's Republic of China
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31
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Abstract
The conventional treatment of infectious agents is increasingly encountering antimicrobial resistance. This resistance has led to an intense search for novel treatment modalities for infectious diseases. Elucidation of the mechanisms underlying the inhibitory activity of chemokines has been instrumental in the rational design of anti-human immunodeficiency virus chemokine drugs. The immune-based therapies, in combination with antimicrobial drugs, for viral hepatitis have attracted much attention. Recognition of toll-like receptors by synthetic immunomodulators is used for certain viral infections. New methodologies have the potential to identify novel targets and foster the development of individually tailored immunomodulatory drug treatments.
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Affiliation(s)
- K Noel Masihi
- Robert Koch Institute, Nordufer 20, D-13353 Berlin, Germany
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32
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Février M, Dorgham K, Rebollo A. CD4+ T cell depletion in human immunodeficiency virus (HIV) infection: role of apoptosis. Viruses 2011; 3:586-612. [PMID: 21994747 PMCID: PMC3185763 DOI: 10.3390/v3050586] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 05/03/2011] [Accepted: 05/04/2011] [Indexed: 02/07/2023] Open
Abstract
Human immunodeficiency virus (HIV) infection is principally a mucosal disease and the gastrointestinal (GI) tract is the major site of HIV replication. Loss of CD4+ T cells and systemic immune hyperactivation are the hallmarks of HIV infection. The end of acute infection is associated with the emergence of specific CD4+ and CD8+ T cell responses and the establishment of a chronic phase of infection. Abnormal levels of immune activation and inflammation persist despite a low steady state level of viremia. Although the causes of persistent immune hyperactivation remain incompletely characterized, physiological alterations of gastrointestinal tract probably play a major role. Failure to restore Th17 cells in gut-associated lymphoid tissues (GALT) might impair the recovery of the gut mucosal barrier. This review discusses recent advances on understanding the contribution of CD4+ T cell depletion to HIV pathogenesis.
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Affiliation(s)
- Michèle Février
- Unité Génomique Virale et Vaccination, CNRS URA3015, Institut Pasteur, 28 rue du Dr Roux, 75015 Paris, France.
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33
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Labrecque J, Metz M, Lau G, Darkes MC, Wong RSY, Bogucki D, Carpenter B, Chen G, Li T, Nan S, Schols D, Bridger GJ, Fricker SP, Skerlj RT. HIV-1 entry inhibition by small-molecule CCR5 antagonists: a combined molecular modeling and mutant study using a high-throughput assay. Virology 2011; 413:231-43. [PMID: 21388649 DOI: 10.1016/j.virol.2011.02.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 02/13/2011] [Accepted: 02/18/2011] [Indexed: 02/01/2023]
Abstract
Based on the attrition rate of CCR5 small molecule antagonists in the clinic the discovery and development of next generation antagonists with an improved pharmacology and safety profile is necessary. Herein, we describe a combined molecular modeling, CCR5-mediated cell fusion, and receptor site-directed mutagenesis approach to study the molecular interactions of six structurally diverse compounds (aplaviroc, maraviroc, vicriviroc, TAK-779, SCH-C and a benzyloxycarbonyl-aminopiperidin-1-yl-butane derivative) with CCR5, a coreceptor for CCR5-tropic HIV-1 strains. This is the first study using an antifusogenic assay, a model of the interaction of the gp120 envelope protein with CCR5. This assay avoids the use of radioactivity and HIV infection assays, and can be used in a high throughput mode. The assay was validated by comparison with other established CCR5 assays. Given the hydrophobic nature of the binding pocket several binding models are suggested which could prove useful in the rational drug design of new lead compounds.
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Affiliation(s)
- Jean Labrecque
- Department of Biology, AnorMED Inc. now Genzyme Corporation, 500 Kendall Street, Cambridge, MA 02142, USA
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34
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Abstract
Infectious diseases continue to impact human morbidity and mortality. Every individual is vulnerable to microbial infections regardless of socioeconomic status, gender, age group or ethnic background. There has been an explosion of international air travel with an estimated 2 billion passengers travelling on commercial airlines every year. The rapid expansion of globalization and mass tourism has facilitated the spread of disease-causing pathogens from one continent to another at unprecedented rates.
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Affiliation(s)
- F.P. Nijkamp
- Faculteit Farmacie, Rijksuniversiteit Utrecht, Utrecht, Netherlands
| | - Michael J. Parnham
- Diseases "Dr. Fran Mihaljevic", Research & Clinical Immunology Unit, University Hospital for Infectious, Mirogojska cesta 8, Zagreb, 10000 Croatia
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Lorenzen T. Profile of maraviroc: a CCR5 antagonist in the management of treatment-experienced HIV patients. HIV AIDS-RESEARCH AND PALLIATIVE CARE 2010; 2:151-6. [PMID: 22096393 PMCID: PMC3218686 DOI: 10.2147/hiv.s4787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Maraviroc is the first and, so far, the only licensed representative of the class of chemokine receptor type 5 (CCR5) inhibitors used for the treatment of human immunodeficiency virus (HIV) infection. Its safety and efficacy were demonstrated in several clinical trials, and its use was approved in 2007 by the responsible authorities. Some specific issues are correlated with maraviroc and its use. It is the only drug in the antiretroviral armamentarium, which does not interact with the viral enzymes but with a human receptor. Hence, it is able to be long-term effective only if the infecting virus uses, exclusively, the CCR5 receptor. Occurrence and detection of the CCR5 tropism are some of the great challenges of maraviroc use in treatment-experienced patients. Although up to 80% of naive patients harbor CCR5-tropic virus, the occurrence of CXCR4 or other tropisms increases with the duration of HIV infection and treatment. Nonetheless, maraviroc is a potent medication for eligible patients and helps to improve the outcome of antiretroviral treatment (ART) of HIV infection.
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Affiliation(s)
- Thore Lorenzen
- IFI Institute for Interdisciplinary Medicine, Hamburg, Germany
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Abstract
Lentiviral vectors have become an important research tool and have just entered into clinical trials. As wild-type lentiviruses engage specific receptors that have limited tropism, most investigators have replaced the endogenous envelope glycoprotein with an alternative envelope. Such pseudotyped vectors have the potential to infect a wide variety of cell types and species. Alternatively, selection of certain viral envelope glycoproteins may also facilitate cell targeting to enhance directed gene transfer. We describe the method for generating pseudotyped vector and provide information regarding available pseudotypes and their respective target tissues.
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Affiliation(s)
- Daniela Bischof
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
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Distinct molecular pathways to X4 tropism for a V3-truncated human immunodeficiency virus type 1 lead to differential coreceptor interactions and sensitivity to a CXCR4 antagonist. J Virol 2010; 84:8777-89. [PMID: 20573813 DOI: 10.1128/jvi.00333-10] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
During the course of infection, transmitted HIV-1 isolates that initially use CCR5 can acquire the ability to use CXCR4, which is associated with an accelerated progression to AIDS. Although this coreceptor switch is often associated with mutations in the stem of the viral envelope (Env) V3 loop, domains outside V3 can also play a role, and the underlying mechanisms and structural basis for how X4 tropism is acquired remain unknown. In this study we used a V3 truncated R5-tropic Env as a starting point to derive two X4-tropic Envs, termed DeltaV3-X4A.c5 and DeltaV3-X4B.c7, which took distinct molecular pathways for this change. The DeltaV3-X4A.c5 Env clone acquired a 7-amino-acid insertion in V3 that included three positively charged residues, reestablishing an interaction with the CXCR4 extracellular loops (ECLs) and rendering it highly susceptible to the CXCR4 antagonist AMD3100. In contrast, the DeltaV3-X4B.c7 Env maintained the V3 truncation but acquired mutations outside V3 that were critical for X4 tropism. In contrast to DeltaV3-X4A.c5, DeltaV3-X4B.c7 showed increased dependence on the CXCR4 N terminus (NT) and was completely resistant to AMD3100. These results indicate that HIV-1 X4 coreceptor switching can involve (i) V3 loop mutations that establish interactions with the CXCR4 ECLs, and/or (ii) mutations outside V3 that enhance interactions with the CXCR4 NT. The cooperative contributions of CXCR4 NT and ECL interactions with gp120 in acquiring X4 tropism likely impart flexibility on pathways for viral evolution and suggest novel approaches to isolate these interactions for drug discovery.
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38
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Jones KL, Roche M, Gantier MP, Begum NA, Honjo T, Caradonna S, Williams BRG, Mak J. X4 and R5 HIV-1 have distinct post-entry requirements for uracil DNA glycosylase during infection of primary cells. J Biol Chem 2010; 285:18603-14. [PMID: 20371602 DOI: 10.1074/jbc.m109.090126] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It has been assumed that R5 and X4 HIV utilize similar strategies to support viral cDNA synthesis post viral entry. In this study, we provide evidence to show that R5 and X4 HIV have distinct requirements for host cell uracil DNA glycosylase (UNG2) during the early stage of infection. UNG2 has been previously implicated in HIV infection, but its precise role remains controversial. In this study we show that, although UNG2 is highly expressed in different cell lines, UNG2 levels are low in the natural host cells of HIV. Short interfering RNA knockdown of endogenous UNG2 in primary cells showed that UNG2 is required for R5 but not X4 HIV infection and that this requirement is bypassed when HIV enters the target cell via vesicular stomatitis virus envelope-glycoprotein-mediated endocytosis. We also show that short interfering RNA knockdown of UNG2 in virus-producing primary cells leads to defective R5 HIV virions that are unable to complete viral cDNA synthesis. Quantitative PCR analysis revealed that endogenous UNG2 levels are transiently up-regulated post HIV infection, and this increase in UNG2 mRNA is approximately 10-20 times higher in R5 versus X4 HIV-infected cells. Our data show that both virion-associated UNG2 and HIV infection-induced UNG2 expression are critical for reverse transcription during R5 but not X4 HIV infection. More importantly, we have made the novel observation that R5 and X4 HIV have distinct host cell factor requirements and differential capacities to induce gene expression during the early stages of infection. These differences may result from activation of distinct signaling cascades and/or infection of divergent T-lymphocyte subpopulations.
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Affiliation(s)
- Kate L Jones
- Centre for Virology, Burnet Institute, Melbourne, Victoria 3004, Australia
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39
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Teeravechyan S, Essex M, Lee TH. Conserved determinants of enhanced CCR5 binding in the human immunodeficiency virus subtype D envelope third variable loop. AIDS Res Hum Retroviruses 2010; 26:481-8. [PMID: 20377425 DOI: 10.1089/aid.2009.0086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Human immunodeficiency virus 1 subtype D (HIV-1D) contributes to a significant portion of the HIV-1 disease burden in eastern and central Africa, and is associated with more rapid disease progression. Its viral envelope sequences, particularly in the third variable region (V3), are highly divergent from other major subtypes yet have rarely been studied to date. We evaluated the V3 and select bridging sheet residues of the HIV-1D 94UG114 envelope by alanine-scanning mutagenesis to determine the residues involved in CCR5 usage conservation in the face of sequence variability. We found most single alanine mutations capable of abolishing CCR5 binding, suggesting binding contacts that are highly sensitive to mutation. Despite drastic binding defects across the board, most mutants mediated fusion at or near wild-type levels, demonstrating an ability to accommodate changes in CCR5 affinity while maintaining the ability to complete entry. Three of the alanine mutations did not abolish CCR5 binding but rather resulted in enhanced CCR5 binding. The positions of these residues were found to be conserved between strains of two subtypes, revealing similar V3 elements that suggest a conservation of constraints in V3 loop conformation.
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Affiliation(s)
- Samaporn Teeravechyan
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts
| | - M. Essex
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts
| | - Tun-Hou Lee
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts
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40
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Structure-function analysis of human immunodeficiency virus type 1 gp120 amino acid mutations associated with resistance to the CCR5 coreceptor antagonist vicriviroc. J Virol 2009; 83:12151-63. [PMID: 19776131 DOI: 10.1128/jvi.01351-09] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vicriviroc (VCV) is a small-molecule CCR5 coreceptor antagonist currently in clinical trials for treatment of R5-tropic human immunodeficiency virus type 1 (HIV-1) infection. With this drug in development, identification of resistance mechanisms to VCV is needed to allow optimal outcomes in clinical practice. In this study we further characterized VCV resistance in a lab-adapted, VCV-resistant RU570 virus (RU570-VCV(res)). We show that K305R, R315Q, and K319T amino acid changes in the V3 loop, along with P437S in C4, completely reproduced the resistance phenotype in a chimeric ADA envelope containing the C2-V5 region from RU570 passage control gp120. The K305R amino acid change primarily impacted the degree of resistance, whereas K319T contributed to both resistance and virus infectivity. The P437S mutation in C4 had more influence on the relative degree of virus infectivity, while the R315Q mutation contributed to the virus concentration-dependent phenotypic resistance pattern observed for RU570-VCV(res). RU570-VCV(res) pseudovirus entry with VCV-bound CCR5 was dramatically reduced by Y10A, D11A, Y14A, and Y15A mutations in the N terminus of CCR5, whereas these mutations had less impact on entry in the absence of VCV. Notably, an additional Q315E/I317F substitution in the crown region of the V3 loop enhanced resistance to VCV, resulting in a stronger dependence on the N terminus for viral entry. By fitting the envelope mutations to a molecular model of a recently described docked N-terminal CCR5 peptide consisting of residues 2 to 15 in complex with HIV-1 gp120 CD4, potential new interactions in gp120 with the N terminus of CCR5 were uncovered. The cumulative results of this study suggest that as the RU570 VCV-resistant virus adapted to use the drug-bound receptor, it also developed an increased reliance on the N terminus of CCR5.
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Adaptive mutations in a human immunodeficiency virus type 1 envelope protein with a truncated V3 loop restore function by improving interactions with CD4. J Virol 2009; 83:11005-15. [PMID: 19692476 DOI: 10.1128/jvi.01238-09] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We previously reported that a human immunodeficiency virus type 1 (HIV-1) clade B envelope protein with a severely truncated V3 loop regained function after passage in tissue culture. The adapted virus, termed TA1, retained the V3 truncation, was exquisitely sensitive to neutralization by the CD4 binding site monoclonal antibody b12 and by HIV-positive human sera, used CCR5 to enter cells, and was completely resistant to small molecule CCR5 antagonists. To examine the mechanistic basis for these properties, we singly and in combination introduced each of the 5 mutations from the adapted clone TA1 into the unadapted envelope. We found that single amino acid changes in the C3 region, the V3 loop, and in the fusion peptide were responsible for imparting near-normal levels of envelope function to TA1. T342A, which resulted in the loss of a highly conserved glycosylation site in C3, played the primary role. The adaptive amino acid changes had no impact on CCR5 antagonist resistance but made virus more sensitive to neutralization by antibodies to the CD4 binding site, modestly enhanced affinity for CD4, and made TA1 more responsive to CD4 binding. Specifically, TA1 was triggered by soluble CD4 more readily than the parental Env and, unlike the parental Env, could mediate entry on cells that express low levels of CD4. In contrast, TA1 interacted with CCR5 less efficiently and was highly sensitive to antibodies that bind to the CCR5 N terminus and ECL2. Therefore, enhanced utilization of CD4 is one mechanism by which HIV-1 can overcome mutations in the V3 region that negatively affect CCR5 interactions.
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42
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Berro R, Sanders RW, Lu M, Klasse PJ, Moore JP. Two HIV-1 variants resistant to small molecule CCR5 inhibitors differ in how they use CCR5 for entry. PLoS Pathog 2009; 5:e1000548. [PMID: 19680536 PMCID: PMC2718843 DOI: 10.1371/journal.ppat.1000548] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 07/20/2009] [Indexed: 12/04/2022] Open
Abstract
HIV-1 variants resistant to small molecule CCR5 inhibitors recognize the inhibitor-CCR5 complex, while also interacting with free CCR5. The most common genetic route to resistance involves sequence changes in the gp120 V3 region, a pathway followed when the primary isolate CC1/85 was cultured with the AD101 inhibitor in vitro, creating the CC101.19 resistant variant. However, the D1/86.16 escape mutant contains no V3 changes but has three substitutions in the gp41 fusion peptide. By using CCR5 point-mutants and gp120-targeting agents, we have investigated how infectious clonal viruses derived from the parental and both resistant isolates interact with CCR5. We conclude that the V3 sequence changes in CC101.19 cl.7 create a virus with an increased dependency on interactions with the CCR5 N-terminus. Elements of the CCR5 binding site associated with the V3 region and the CD4-induced (CD4i) epitope cluster in the gp120 bridging sheet are more exposed on the native Env complex of CC101.19 cl.7, which is sensitive to neutralization via these epitopes. However, D1/86.16 cl.23 does not have an increased dependency on the CCR5 N-terminus, and its CCR5 binding site has not become more exposed. How this virus interacts with the inhibitor-CCR5 complex remains to be understood. Human immunodeficiency virus type 1 (HIV-1) is the causative agent of AIDS. HIV-1 entry into target cells is triggered by the interaction of the viral envelope glycoproteins with a cell-surface receptor (CD4) and a co-receptor (CCR5), and culminates in fusion of the viral and cell membranes. Small molecule inhibitors that bind to CCR5 are a new class of drug for treating HIV-1-infected people. However, HIV-1 can evolve ways to become resistant to these compounds, by acquiring mutations that alter how its envelope glycoproteins (gp120-gp41) interact with CCR5. In this study, we investigated how two resistant viruses gained the ability to use the inhibitor-bound form of CCR5 through two different mechanisms. In the first virus, four amino acid substitutions in the V3 region of gp120 created an increased dependency on interactions with the CCR5 N-terminus. These changes altered the configuration of gp120, increasing the exposure of antibody epitopes in the V3 region and the CD4i epitope cluster associated with the CCR5 binding site. In contrast, the second virus, which became resistant via three sequence changes in the gp41 subunit, did not become more dependent on the CCR5 N-terminus and remained resistant to neutralization by antibodies against elements of the CCR5 binding site.
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Affiliation(s)
- Reem Berro
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Rogier W. Sanders
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Min Lu
- Department of Biochemistry, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Per J. Klasse
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, United States of America
| | - John P. Moore
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, United States of America
- * E-mail:
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Heterosexual transmission of human immunodeficiency virus type 1 subtype C: Macrophage tropism, alternative coreceptor use, and the molecular anatomy of CCR5 utilization. J Virol 2009; 83:8208-20. [PMID: 19515785 DOI: 10.1128/jvi.00296-09] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Human immunodeficiency virus type 1 transmission selects for virus variants with genetic characteristics distinct from those of donor quasispecies, but the biological factors favoring their transmission or establishment in new hosts are poorly understood. We compared primary target cell tropisms and entry coreceptor utilizations of donor and recipient subtype C Envs obtained near the time of acute infection from Zambian heterosexual transmission pairs. Both donor and recipient Envs demonstrated only modest macrophage tropism, and there was no overall difference between groups in macrophage or CD4 T-cell infection efficiency. Several individual pairs showed donor/recipient differences in primary cell infection, but these were not consistent between pairs. Envs had surprisingly broad uses of GPR15, CXCR6, and APJ, but little or no use of CCR2b, CCR3, CCR8, GPR1, and CXCR4. Donors overall used GPR15 better than did recipients. However, while several individual pairs showed donor/recipient differences for GPR15 and/or other coreceptors, the direction of the differences was inconsistent, and several pairs had unique alternative coreceptor patterns that were conserved across the transmission barrier. CCR5/CCR2b chimeras revealed that recipients as a group were more sensitive than were donors to replacement of the CCR5 extracellular loops with corresponding regions of CCR2b, but significant differences in this direction were not consistent within pairs. These data show that sexual transmission does not select for enhanced macrophage tropism, nor for preferential use of any alternative coreceptor. Recipient Envs are somewhat more constrained than are donors in flexibility of CCR5 use, but this pattern is not universal for all pairs, indicating that it is not an absolute requirement.
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Abstract
PURPOSE OF REVIEW We discuss the current knowledge concerning the biology of CXCR4 and CCR5 and their roles in HIV-1 infection. RECENT FINDINGS Important research findings reported in the last 2 years have advanced our knowledge in the field of HIV coreceptors and pathogenesis. Novel methods have been used to crystallize two new members of the G-protein coupled receptors. It has been demonstrated that expression and stability of the naturally occurring truncated CCR5 protein is critical for resistance to HIV-1. The first stem cell transplantation of donor cells with the CCR5 mutation provided proof of principle. The Food and Drug Administration approved the first CCR5-based entry inhibitor. New CXCL12 isoforms were discovered, one isoform is a potent X4 inhibitor with weak chemotaxis activity. SUMMARY The coreceptor discoveries revealed new insights into host and viral factors influencing HIV transmission and disease. The HIV/coreceptor interaction has become a major target for the development of novel antiviral strategies to treat and prevent HIV infection. The first CCR5-based entry inhibitor has been recently approved. New drugs that promote CCR5 and CXCR4 internalization, independent of cellular signaling, might provide clinical benefits with minimum side effects.
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45
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Abstract
PURPOSE OF REVIEW Small molecule inhibitors targeting the CCR5 coreceptor represent a new class of drugs for treating HIV-1 infection. Maraviroc has received regulatory approvals, and vicriviroc is in phase 3 trials. Understanding how resistance to these drugs develops and is diagnosed is essential to guide clinical practice. We review what has been learned from in-vitro resistance studies, and how this relates to what is being seen, or can be anticipated, in clinical studies. RECENT FINDINGS The principal resistance pathway in vitro involves continued use of CCR5 in an inhibitor-insensitive manner; the resistant viruses recognize the inhibitor-CCR5 complex, as well as free CCR5. Switching to use the CXCR4 coreceptor is rare. The principal genetic pathway involves accumulating 2-4 sequence changes in the gp120 V3 region, but a non-V3 pathway is also known. The limited information available from clinical studies suggests that a similar escape process is followed in vivo. However, the most common change associated with virologic failure involves expansion of pre-existing, CXCR4-using viruses that are insensitive to CCR5 inhibitors. SUMMARY HIV-1 escapes small molecule CCR5 inhibitors by continuing to use CCR5 in an inhibitor-insensitive manner, or evades them by expanding naturally insensitive, CXCR4-using variants.
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Affiliation(s)
- John P Moore
- Weill Medical College of Cornell University, New York, NY 10065, USA.
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46
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Computer-based design of novel HIV-1 entry inhibitors: neomycin conjugated to arginine peptides at two specific sites. J Mol Model 2008; 15:281-94. [DOI: 10.1007/s00894-008-0401-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 10/03/2008] [Indexed: 10/21/2022]
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47
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Abstract
In this review, the author discusses recent advances in anti-HIV inhibitors, targeting CXCR4, including natural and modified chemokines, peptides and organic compounds, their mechanisms of action, and the molecular process of virus invasion of immune cells. Peptides with strong anti-HIV activity exhibit several common features, such as electrostatic charges, cyclization, beta-turns and dimerization induced by a sulphide bond. Organic compounds, such as cyclams, display a unique metal-mediated mechanism in the binding process to its target CXCR4. Understanding of their mechanisms of action may be useful for the design of more effective drugs. Consecutive interactions of viral glycoprotein gp120 with CD4 and the co-receptor, CXCR4 or another co-receptor CCR5 on the cell surface leads to virus invasion into host cells. The molecular details of the binding between HIV glycoproteins and the co-receptors also provide a basis for anti-HIV therapy.
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Affiliation(s)
- Xiangyang Liang
- Department of Biochemistry, 117 Schweitzer Hall, University of Missouri, Columbia, MO 65211, USA.
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48
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Lapidot A, Peled A, Berchanski A, Pal B, Kollet O, Lapidot T, Borkow G. NeoR6 inhibits HIV-1-CXCR4 interaction without affecting CXCL12 chemotaxis activity. Biochim Biophys Acta Gen Subj 2008; 1780:914-20. [DOI: 10.1016/j.bbagen.2008.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2007] [Revised: 03/05/2008] [Accepted: 03/07/2008] [Indexed: 11/30/2022]
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49
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Barbonetti A, Vassallo MRC, Antonangelo C, Nuccetelli V, D'Angeli A, Pelliccione F, Giorgi M, Francavilla F, Francavilla S. RANTES and human sperm fertilizing ability: effect on acrosome reaction and sperm/oocyte fusion. Mol Hum Reprod 2008; 14:387-91. [PMID: 18490356 DOI: 10.1093/molehr/gan031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Beta-chemokine, regulated on activation and normally T-cell expressed and presumably secreted (RANTES), is present in both the male and female genital tract fluids where its levels increase in diseases related to infertility, such as endometriosis and male genital tract infections. beta-Chemokine receptors (CCR3 and CCR5) are expressed on freshly ejaculated human sperm cells and a sperm chemoattractant effect for RANTES has been reported. No information exists on other possible roles of RANTES on sperm functions involved in the fertilization process. In the present study, the exposure of sperm suspensions to high concentrations of the chemokine, comparable to those observed in inflammatory diseases, significantly decreased the stimulatory effect exerted by progesterone on sperm/oocyte fusion, evaluated by means of the hamster egg penetration test. Accordingly, a large proportion of spermatozoa preincubated under capacitating conditions with high concentrations of RANTES underwent a premature acrosome reaction (AR) that prevented subsequent progesterone-induced AR. Finally, sperm samples exposed to the same high levels of chemokine showed a significant increase in the intracellular levels of cAMP, which is involved in capacitation and AR dynamics. These results indicate a negative interference of high levels of RANTES on the sperm fertilizing ability, thereby suggesting a potential contribution of this chemokine to subfertility associated with endometriosis and genital tract inflammatory diseases.
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Affiliation(s)
- A Barbonetti
- Andrologic Unit, Department of Internal Medicine, University of L'Aquila, Blocco 11, Coppito 67100, Coppito, L'Aquila, Italy
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50
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Harada S, Monde K, Tanaka Y, Kimura T, Maeda Y, Yusa K. Neutralizing antibodies decrease the envelope fluidity of HIV-1. Virology 2008; 370:142-50. [PMID: 17900650 DOI: 10.1016/j.virol.2007.08.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Revised: 08/06/2007] [Accepted: 08/17/2007] [Indexed: 11/28/2022]
Abstract
For successful penetration of HIV-1, the formation of a fusion pore may be required in order to accumulate critical numbers of fusion-activated gp41 with the help of fluidization of the plasma membrane and viral envelope. An increase in temperature to 40 degrees C after viral adsorption at 25 degrees C enhanced the infectivity by 1.4-fold. The enhanced infectivity was inhibited by an anti-CXCR4 peptide, T140, and anti-V3 monoclonal antibodies (0.5beta and 694/98-D) by post-attachment neutralization, but not by non-neutralizing antibodies (670-30D and 246-D) specific for the C5 of gp120 and cluster I of gp41, respectively. Anti-HLA-II and an anti-HTLV-I gp46 antibody, LAT27, neutralized the molecule-carrying HIV-1(C-2(MT-2)). The anti-V3 antibodies suppressed the fluidity of the HIV-1(C-2) envelope, whereas the non-neutralizing antibodies did not. The anti-HLA-II antibody decreased the envelope fluidity of HIV-1(C-2(MT-2)), but not that of HIV-1(C-2). Therefore, fluidity suppression by these antibodies represents an important neutralization mechanism, in addition to inhibition of viral attachment.
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Affiliation(s)
- Shinji Harada
- Department of Medical Virology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
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