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Mori L, Valente ST. Cure and Long-Term Remission Strategies. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2407:391-428. [PMID: 34985678 DOI: 10.1007/978-1-0716-1871-4_26] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The majority of virally suppressed individuals will experience rapid viral rebound upon antiretroviral therapy (ART) interruption, providing a strong rationale for the development of cure strategies. Moreover, despite ART virological control, HIV infection is still associated with chronic immune activation, inflammation, comorbidities, and accelerated aging. These effects are believed to be due, in part, to low-grade persistent transcription and trickling production of viral proteins from the pool of latent proviruses constituting the viral reservoir. In recent years there has been an increasing interest in developing what has been termed a functional cure for HIV. This approach entails the long-term, durable control of viral expression in the absence of therapy, preventing disease progression and transmission, despite the presence of detectable integrated proviruses. One such strategy, the block-and-lock approach for a functional cure, proposes the epigenetic silencing of proviral expression, locking the virus in a profound latent state, from which reactivation is very unlikely. The proof-of-concept for this approach was demonstrated with the use of a specific small molecule targeting HIV transcription. Here we review the principles behind the block-and-lock approach and some of the additional strategies proposed to silence HIV expression.
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Affiliation(s)
- Luisa Mori
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Susana T Valente
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA.
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2
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Zhu S, Meng Q, Schooley RT, An J, Xu Y, Huang Z. Structural and Biological Characterizations of Novel High-Affinity Fluorescent Probes with Overlapped and Distinctive Binding Regions on CXCR4. Molecules 2019; 24:molecules24162928. [PMID: 31412600 PMCID: PMC6720714 DOI: 10.3390/molecules24162928] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/09/2019] [Accepted: 08/10/2019] [Indexed: 01/25/2023] Open
Abstract
CXC-type chemokine receptor 4 (CXCR4) is well known as a co-receptor for cellular entry and infection of human immunodeficiency virus type 1 (HIV-1). As an important member of the G protein-coupled receptor (GPCR) family, CXCR4 also mediates a variety of cellular processes and functions, such as cell chemotaxis, proliferation, and calcium signal transductions. Identification and characterization of molecular ligands or probes of CXCR4 have been an intensive area of investigations as such ligands or probes are of significant clinical values for the studies and treatments of HIV-1 infection and other human diseases mediated by the receptor. The crystal structures of CXCR4 in complex with different ligands have revealed two distinctive binding regions or subpockets. Thus, understanding the interactions of diverse ligands with these distinctive CXCR4 binding regions has become vital for elucidating the relationship between binding modes and biological mechanisms of ligand actions. Peptidic CVX15 is the only ligand that has been validated to bind one of these distinctive binding regions (or so called the major subpocket) of CXCR4. Therefore, in this study, we developed an efficient probe system including two high-affinity peptidic fluorescent probes, designated as FITC-CVX15 and FITC-DV1, with the aim of targeting distinctive CXCR4 subpockets. We conducted rational design and chemical characterization of the two CXCR4-specific probes and examined their application in biological experiments including competitive binding assays, flow cytometry analysis, and confocal imaging. Especially these two probes were applied in parallel CXCR4 competitive binding assays to detect and analyze potential binding modes of diverse CXCR4 ligands, together with molecular docking and simulations. Our results have indicated that these peptidic fluorescent probe systems provide novel ligand detecting tools, as well as present a new approach for analyzing distinctive binding modes of diverse CXCR4 ligands.
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Affiliation(s)
- Siyu Zhu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
- Department of Medicine, Division of Infectious Diseases and Global Public Health, School of Medicine, University of California San Diego, La Jolla, CA 92037, USA
| | - Qian Meng
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Robert T Schooley
- Department of Medicine, Division of Infectious Diseases and Global Public Health, School of Medicine, University of California San Diego, La Jolla, CA 92037, USA
| | - Jing An
- Department of Medicine, Division of Infectious Diseases and Global Public Health, School of Medicine, University of California San Diego, La Jolla, CA 92037, USA
| | - Yan Xu
- School of Life and Health Sciences, Chinese University of Hong Kong, Shenzhen 518172, China.
| | - Ziwei Huang
- School of Life Sciences, Tsinghua University, Beijing 100084, China.
- Department of Medicine, Division of Infectious Diseases and Global Public Health, School of Medicine, University of California San Diego, La Jolla, CA 92037, USA.
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3
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Choi WT, Yang Y, Xu Y, An J. Targeting chemokine receptor CXCR4 for treatment of HIV-1 infection, tumor progression, and metastasis. Curr Top Med Chem 2016; 14:1574-89. [PMID: 25159167 DOI: 10.2174/1568026614666140827143541] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 05/30/2014] [Accepted: 06/06/2014] [Indexed: 12/17/2022]
Abstract
The chemokine receptor CXCR4 is required for the entry of human immunodeficiency virus type 1 (HIV-1) into target cells and for the development and dissemination of various types of cancers, including gastrointestinal, cutaneous, head and neck, pulmonary, gynecological, genitourinary, neurological, and hematological malignancies. The T-cell (T)-tropic HIV-1 strains use CXCR4 as the entry coreceptor; consequently, multiple CXCR4 antagonistic inhibitors have been developed for the treatment of acquired immune deficiency syndrome (AIDS). However, other potential applications of CXCR4 antagonists have become apparent since its discovery in 1996. In fact, increasing evidence demonstrates that epithelial and hematopoietic tumor cells exploit the interaction between CXCR4 and its natural ligand, stromal cellderived factor (SDF)-1α, which normally regulates leukocyte migration. The CXCR4 and/or SDF-1α expression patterns in tumor cells also determine the sites of metastatic spread. In addition, the activation of CXCR4 by SDF-1α promotes invasion and proliferation of tumor cells, enhances tumor-associated neoangiogenesis, and assists in the degradation of the extracellular matrix and basement membrane. As such, the evaluation of CXCR4 and/or SDF-1α expression levels has a significant prognostic value in various types of malignancies. Several therapeutic challenges remain to be overcome before the use of CXCR4 inhibitors can be translated into clinical practice, but promising preclinical data demonstrate that CXCR4 antagonists can mobilize tumor cells from their protective microenvironments, interfere with their metastatic and tumorigenic potentials, and/or make tumor cells more susceptible to chemotherapy.
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Affiliation(s)
| | | | | | - Jing An
- Department of Pharmacology, State University of New York, Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA.
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4
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Ishida Y, Yoneda M, Otsuki H, Watanabe Y, Kato F, Matsuura K, Kikukawa M, Matsushita S, Hishiki T, Igarashi T, Miura T. Generation of a neutralization-resistant CCR5 tropic simian/human immunodeficiency virus (SHIV-MK38) molecular clone, a derivative of SHIV-89.6. J Gen Virol 2016; 97:1249-1260. [PMID: 26850058 DOI: 10.1099/jgv.0.000421] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Previously, we reported that a new genetically diverse CCR5 (R5) tropic simian/human immunodeficiency virus (SHIV-MK38) adapted to rhesus monkeys became more neutralization resistant to SHIV-infected plasma than did the parental SHIV-KS661 clone. Here, to clarify the significance of the neutralization-resistant phenotype of SHIV in a macaque model, we initially investigated the precise neutralization phenotype of the SHIVs, including SHIV-MK38 molecular clones, using SHIV-MK38-infected plasma, a pooled plasma of human immunodeficiency virus (HIV)-infected individuals, soluble CD4 and anti-HIV-1 neutralizing mAbs, the epitopes of which were known. The results show that SHIV-KS661 had tier 1 neutralization sensitivity, but monkey-adapted R5 tropic SHIV-MK38 acquired neutralization resistance similar to that of tier 2 or 3 as a clone virus. Sequence analysis of the env gene suggested that the neutralization-resistant phenotype of SHIV-MK38 was acquired by conformational changes in Env associated with the net charge and potential N-linked glycosylation sites. To examine the relationship between neutralization phenotype and stably persistent infection in monkeys, we performed in vivo rectal inoculation experiments using a SHIV-MK38 molecular clone. The results showed that one of three rhesus monkeys exhibited durable infection with a plasma viral load of 105 copies ml- 1 despite the high antibody responses that occurred in the host. Whilst further improvements are required in the development of a challenge virus, it will be useful to generate a neutralization-resistant R5 tropic molecular clone of the SHIV-89.6 lineage commonly used for vaccine development - a result that can be used to explore the foundation of AIDS pathogenesis.
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Affiliation(s)
- Yuki Ishida
- Laboratory of Primate Model, Experimental Research Center for Infectious Diseases, Institute for Virus Research,Kyoto University, 53 Shogoinkawaharacho, Sakyo-ku, Kyoto 606-8507,Japan
| | - Mai Yoneda
- Laboratory of Primate Model, Experimental Research Center for Infectious Diseases, Institute for Virus Research,Kyoto University, 53 Shogoinkawaharacho, Sakyo-ku, Kyoto 606-8507,Japan
| | - Hiroyuki Otsuki
- Laboratory of Primate Model, Experimental Research Center for Infectious Diseases, Institute for Virus Research,Kyoto University, 53 Shogoinkawaharacho, Sakyo-ku, Kyoto 606-8507,Japan
| | - Yuji Watanabe
- Laboratory of Primate Model, Experimental Research Center for Infectious Diseases, Institute for Virus Research,Kyoto University, 53 Shogoinkawaharacho, Sakyo-ku, Kyoto 606-8507,Japan
| | - Fumihiro Kato
- Laboratory of Primate Model, Experimental Research Center for Infectious Diseases, Institute for Virus Research,Kyoto University, 53 Shogoinkawaharacho, Sakyo-ku, Kyoto 606-8507,Japan
| | - Kanako Matsuura
- Laboratory of Primate Model, Experimental Research Center for Infectious Diseases, Institute for Virus Research,Kyoto University, 53 Shogoinkawaharacho, Sakyo-ku, Kyoto 606-8507,Japan
| | - Minako Kikukawa
- Laboratory of Primate Model, Experimental Research Center for Infectious Diseases, Institute for Virus Research,Kyoto University, 53 Shogoinkawaharacho, Sakyo-ku, Kyoto 606-8507,Japan
| | - Shuzo Matsushita
- Division of Clinical Retrovirology and Infectious Diseases, Center for AIDS Research,Kumamoto University, Kumamoto 860-0811,Japan
| | - Takayuki Hishiki
- Laboratory of Primate Model, Experimental Research Center for Infectious Diseases, Institute for Virus Research,Kyoto University, 53 Shogoinkawaharacho, Sakyo-ku, Kyoto 606-8507,Japan
| | - Tatsuhiko Igarashi
- Laboratory of Primate Model, Experimental Research Center for Infectious Diseases, Institute for Virus Research,Kyoto University, 53 Shogoinkawaharacho, Sakyo-ku, Kyoto 606-8507,Japan
| | - Tomoyuki Miura
- Laboratory of Primate Model, Experimental Research Center for Infectious Diseases, Institute for Virus Research,Kyoto University, 53 Shogoinkawaharacho, Sakyo-ku, Kyoto 606-8507,Japan
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5
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Progress toward rationally designed small-molecule peptide and peptidomimetic CXCR4 antagonists. Future Med Chem 2015; 7:1261-83. [DOI: 10.4155/fmc.15.64] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Over the last 5 years, X-ray structures of CXCR4 in complex with three different ligands (the small-molecule antagonist IT1t, the polypeptide antagonist CVX15 and the viral chemokine antagonist vMIP-II) have been released. In addition to the inherent scientific value of these specific X-ray structures, they provide a reliable structural foundation for studies of the molecular interactions between CXCR4 and its key peptide ligands (CXCL12 and HIV-1 gp120), and serve as valuable templates for further development of small-molecule CXCR4 antagonists with therapeutic potential. We here review recent computational studies of the molecular interactions between CXCR4 and its peptide ligands – based on the X-ray structures of CXCR4 – and the current status of small-molecule peptide and peptidomimetic CXCR4 antagonists.
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6
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Méndez-Samperio P. Peptidomimetics as a new generation of antimicrobial agents: current progress. Infect Drug Resist 2014; 7:229-37. [PMID: 25210467 PMCID: PMC4155802 DOI: 10.2147/idr.s49229] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Antibiotic resistance is an increasing public health concern around the world. Rapid increase in the emergence of multidrug-resistant bacteria has been the target of extensive research efforts to develop a novel class of antibiotics. Antimicrobial peptides (AMPs) are small cationic amphiphilic peptides, which play an important role in the defense against bacterial infections through disruption of their membranes. They have been regarded as a potential source of future antibiotics, owing to a remarkable set of advantageous properties such as broad-spectrum activity, and they do not readily induce drug-resistance. However, AMPs have some intrinsic drawbacks, such as susceptibility to enzymatic degradation, toxicity, and high production cost. Currently, a new class of AMPs termed “peptidomimetics” have been developed, which can mimic the bactericidal mechanism of AMPs, while being stable to enzymatic degradation and displaying potent activity against multidrug-resistant bacteria. This review will focus on current findings of antimicrobial peptidomimetics. The potential future directions in the development of more potent analogs of peptidomimetics as a new generation of antimicrobial agents are also presented.
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Affiliation(s)
- Patricia Méndez-Samperio
- Department of Immunology, National School of Biological Sciences, National Polytechnic Institute, Mexico City, Mexico
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7
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Abstract
The human immunodeficiency virus (HIV) enters cells through a series of molecular interactions between the HIV envelope protein and cellular receptors, thus providing many opportunities to block infection. Entry inhibitors are currently being used in the clinic, and many more are under development. Unfortunately, as is the case for other classes of antiretroviral drugs that target later steps in the viral life cycle, HIV can become resistant to entry inhibitors. In contrast to inhibitors that block viral enzymes in intracellular compartments, entry inhibitors interfere with the function of the highly variable envelope glycoprotein as it continuously adapts to changing immune pressure and available target cells in the extracellular environment. Consequently, pathways and mechanisms of resistance for entry inhibitors are varied and often involve mutations across the envelope gene. This review provides a broad overview of entry inhibitor resistance mechanisms that inform our understanding of HIV entry and the design of new inhibitors and vaccines.
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Affiliation(s)
- Christopher J De Feo
- Office of Vaccine Research and Review, Center for Biologics Evaluation and Research, US Food and Drug Administration, 8800 Rockville Pike, Bethesda, MD 20892, USA.
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8
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Kuil J, Buckle T, van Leeuwen FWB. Imaging agents for the chemokine receptor 4 (CXCR4). Chem Soc Rev 2012; 41:5239-61. [PMID: 22743644 DOI: 10.1039/c2cs35085h] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The interaction between the chemokine receptor 4 (CXCR4) and stromal cell-derived factor-1 (SDF-1, also known as CXCL12) is a natural regulatory process in the human body. However, CXCR4 over-expression is also found in diseases such as cancer, where it plays a role in, among others, the metastatic spread. For this reason it is an interesting biomarker for the field of diagnostic oncology, and therefore, it is gaining increasing interest for applications in molecular imaging. Especially "small-molecule" imaging agents based on T140, FC131 and AMD3100 have been extensively studied. SDF-1, antibodies, pepducins and bioluminescence have also been used to visualize CXCR4. In this critical review reported CXCR4 targeting imaging agents are described based on their affinity, specificity and biodistribution. The level wherein CXCR4 is up-regulated in cancer patients and its relation to the different cell lines and animal models used to evaluate the efficacy of the imaging agents is also discussed (221 references).
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Affiliation(s)
- Joeri Kuil
- Department of Radiology, Interventional Molecular Imaging, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
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9
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Oishi S, Fujii N. Peptide and peptidomimetic ligands for CXC chemokine receptor 4 (CXCR4). Org Biomol Chem 2012; 10:5720-31. [DOI: 10.1039/c2ob25107h] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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10
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Choi WT, Duggineni S, Xu Y, Huang Z, An J. Drug discovery research targeting the CXC chemokine receptor 4 (CXCR4). J Med Chem 2011; 55:977-94. [PMID: 22085380 DOI: 10.1021/jm200568c] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Won-Tak Choi
- Department of Pathology, The University of Washington School of Medicine, Seattle, Washington 98195, United States
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11
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Lalonde MS, Lobritz MA, Ratcliff A, Chamanian M, Athanassiou Z, Tyagi M, Wong J, Robinson JA, Karn J, Varani G, Arts EJ. Inhibition of both HIV-1 reverse transcription and gene expression by a cyclic peptide that binds the Tat-transactivating response element (TAR) RNA. PLoS Pathog 2011; 7:e1002038. [PMID: 21625572 PMCID: PMC3098202 DOI: 10.1371/journal.ppat.1002038] [Citation(s) in RCA: 53] [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: 10/07/2010] [Accepted: 03/04/2011] [Indexed: 11/18/2022] Open
Abstract
The RNA response element TAR plays a critical role in HIV replication by
providing a binding site for the recruitment of the viral transactivator protein
Tat. Using a structure-guided approach, we have developed a series of
conformationally-constrained cyclic peptides that act as structural mimics of
the Tat RNA binding region and block Tat-TAR interactions at nanomolar
concentrations in vitro. Here we show that these compounds
block Tat-dependent transcription in cell-free systems and in cell-based
reporter assays. The compounds are also cell permeable, have low toxicity, and
inhibit replication of diverse HIV-1 strains, including both CXCR4-tropic and
CCR5-tropic primary HIV-1 isolates of the divergent subtypes A, B, C, D and
CRF01_AE. In human peripheral blood mononuclear cells, the cyclic peptidomimetic
L50 exhibited an IC50 ∼250 nM. Surprisingly, inhibition of
LTR-driven HIV-1 transcription could not account for the full antiviral
activity. Timed drug-addition experiments revealed that L-50 has a bi-phasic
inhibition curve with the first phase occurring after HIV-1 entry into the host
cell and during the initiation of HIV-1 reverse transcription. The second phase
coincides with inhibition of HIV-1 transcription. Reconstituted reverse
transcription assays confirm that HIV-1 (−) strand strong stop DNA
synthesis is blocked by L50-TAR RNA interactions in-vitro.
These findings are consistent with genetic evidence that TAR plays critical
roles both during reverse transcription and during HIV gene expression. Our
results suggest that antiviral drugs targeting TAR RNA might be highly effective
due to a dual inhibitory mechanism. The HIV-1 transactivator protein (Tat), together with the elongation factor
P-TEFb binds to an HIV-1 RNA secondary structure in the 5′-UTRs of nascent
viral mRNAs (TAR) and promotes transcription elongation. This process has been
an attractive target for drug development but previous inhibitors that bind
either Tat or TAR have been plagued by poor inhibition of virus replication,
limited cell penetration, and off-target effects. In this article, we describe a
series of rationally designed cyclic peptides that block Tat-TAR interactions.
L50, the most potent of these compounds, inhibits a wide range of HIV-1 strains
from around the world. Remarkably, L50 inhibits two distinct steps in the HIV-1
lifecycle. As expected, L50 inhibits Tat-dependent HIV-1 transcription, but the
majority of its anti-HIV activity is due to a block in reverse transcription,
i.e. synthesis of the proviral DNA from the RNA genome. L50 inhibition of
reverse transcription reveals an important role for TAR RNA during reverse
transcription as well as providing one of first examples of a drug with a dual
mechanism of action.
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Affiliation(s)
- Matthew S. Lalonde
- Department of Biochemistry, Case Western
Reserve University, Cleveland, Ohio, United States of America
| | - Michael A. Lobritz
- Department of Molecular Biology and
Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of
America
| | - Annette Ratcliff
- Department of Molecular Biology and
Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of
America
| | - Mastooreh Chamanian
- Department of Molecular Biology and
Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of
America
| | - Zafiria Athanassiou
- Department of Chemistry and Department of
Biochemistry, University of Washington, Seattle, Washington, United States of
America
| | - Mudit Tyagi
- Department of Molecular Biology and
Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of
America
| | - Julian Wong
- Department of Molecular Biology and
Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of
America
| | - John A. Robinson
- Department of Chemistry, University of Zurich,
Zurich, Switzerland
| | - Jonathan Karn
- Department of Molecular Biology and
Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of
America
| | - Gabriele Varani
- Department of Chemistry and Department of
Biochemistry, University of Washington, Seattle, Washington, United States of
America
| | - Eric J. Arts
- Department of Molecular Biology and
Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of
America
- Division of Infectious Diseases, Department of
Medicine, Case Western Reserve University, Cleveland, Ohio, United States of
America
- * E-mail:
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12
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Choi WT, An J. Biology and clinical relevance of chemokines and chemokine receptors CXCR4 and CCR5 in human diseases. Exp Biol Med (Maywood) 2011; 236:637-47. [PMID: 21565895 DOI: 10.1258/ebm.2011.010389] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chemokines and their receptors are implicated in a wide range of human diseases, including acquired immune deficiency syndrome (AIDS). The entry of human immunodeficiency virus type 1 (HIV-1) into a cell is initiated by the interaction of the virus's surface envelope proteins with two cell surface components of the target cell, namely CD4 and a chemokine co-receptor, usually CXCR4 or CCR5. Typical anti-HIV-1 agents include protease and reverse transcriptase inhibitors, but the targets of these agents tend to show rapid mutation rates. As such, strategies based on HIV-1 co-receptors have appeal because they target invariant host determinants. Chemokines and their receptors are also of general interest since they play important roles in numerous physiological and pathological processes in addition to AIDS. Therefore, intensive basic and translational research is ongoing for the dissection of their structure - function relationships in an effort to understand the molecular mechanism of chemokine - receptor interactions and signal transductions across cellular membranes. This paper reviews and discusses recent advances and the translation of new knowledge and discoveries into novel interventional strategies for clinical application.
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Affiliation(s)
- Won-Tak Choi
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA
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13
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Churchill EN, Qvit N, Mochly-Rosen D. Rationally designed peptide regulators of protein kinase C. Trends Endocrinol Metab 2009; 20:25-33. [PMID: 19056296 PMCID: PMC2714361 DOI: 10.1016/j.tem.2008.10.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 09/30/2008] [Accepted: 10/01/2008] [Indexed: 11/23/2022]
Abstract
Protein-protein interactions sequester enzymes close to their substrates. Protein kinase C (PKC) is one example of a ubiquitous signaling molecule with effects that are dependent upon localization. Short peptides derived from interaction sites between each PKC isozyme and its receptor for activated C kinase act as highly specific inhibitors and have become available as selective drugs in basic research and animal models of human diseases, such as myocardial infarction and hyperglycemia. Whereas the earlier inhibitory peptides are highly specific, we believe that peptides targeting additional interactions between PKC and selective substrates will generate even more selective tools that regulate different functions of individual isozymes. Here, we discuss the methodologies and applications for identifying selective regulators of PKC.
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Affiliation(s)
- Eric N Churchill
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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14
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Lapidot A, Berchanski A, Borkow G. Insight into the mechanisms of aminoglycoside derivatives interaction with HIV-1 entry steps and viral gene transcription. FEBS J 2008; 275:5236-57. [PMID: 18803669 DOI: 10.1111/j.1742-4658.2008.06657.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In recent years, based on peptide models of HIV-1 RNA binding, NMR structures of Tat-responsive element-ligand complexes and aminoglycoside-RNA interactions, and HIV-1 Tat structure, we have designed and synthesized aminoglycoside-arginine conjugates (AACs) and aminoglycoside poly-arginine conjugates (APACs), to serve as Tat mimetics. These novel molecules inhibit HIV-1 infectivity with 50% effective concentration values in the low micromolar range, the most potent compounds being the hexa-arginine-neomycin B and nona-D-arginine-neomycin conjugates. Importantly, these compounds, in addition to acting as Tat antagonists, inhibit HIV-1 infectivity by blocking several steps in HIV-1 cell entry. The AACs and APACs inhibit HIV-1 cell entry by interacting with gp120 at the CD4-binding site, by interacting with CXCR4 at the binding site of the CXCR4 mAb 12G5, and apparently by interacting with transient structures of the ectodomain of gp41. In the current review, we discuss the mechanisms of anti-HIV-1 activities of these AACs, APACs and other aminoglycoside derivatives in detail. Targeting several key processes in the viral life cycle by the same compound not only may increase its antiviral efficacy, but more importantly, may reduce the capacity of the virus to develop resistance to the compound. AACs and APACs may thus serve as leading compounds for the development of multitargeting novel HIV-1 inhibitors.
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Affiliation(s)
- Aviva Lapidot
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot, Israel.
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15
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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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16
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Zhou J, Wang G, Zhang LH, Ye XS. Modifications of aminoglycoside antibiotics targeting RNA. Med Res Rev 2007; 27:279-316. [PMID: 16892199 DOI: 10.1002/med.20085] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The increased awareness of the central role of RNA has led to realization that RNA, as structural and functional information accumulation, is also drug target to small molecular therapy. Aminoglycosides are a group of well-known antibiotics, which function through binding to specific sites in prokaryotic ribosomal RNA (rRNA) and affecting the fidelity of protein synthesis. Unfortunately, their clinical practice has been curtailed by toxicity and rapid increasing number of resistant strains. Therefore, it is highly desirable to design new modified aminoglycosides that will overcome the undesirable properties of natural occurring aminoglycosides. On the other hand, aminoglycosides as potential antiviral (HIV) agents were also reported. Herein, we survey the current efforts to develop new aminoglycoside derivatives with modification and reconstruction on each sugar ring and review the latest advances in structure-activity relationships (SAR).
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Affiliation(s)
- Jian Zhou
- The State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100083, China
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17
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Abstract
Tumor cells are known to adapt to and utilize existing physiological mechanisms to promote survival and metastasis. The role of the microenvironment in the establishment of a metastatic lesion has become increasingly important as several factors secreted by stromal cells regulate metastatic pattern in a variety of tumor types. Tumor cells interact with osteoblasts, osteoclasts and bone matrix to form a vicious cycle that is essential for successful metastases. Here we review the current concepts regarding the role of an important chemokine/chemokine receptor (SDF-1 or CXCL12/CXCR4) pathway in tumor development and metastasis. CXCL12 secretion by stromal cells is known to attract cancer cells via stimulation of the CXCR4 receptor that is up regulated by tumor cells. CXCL12/CXCR4 activation regulates the pattern of metastatic spread with organs expressing high levels of CXCL12 developing secondary tumors (i.e., the bone marrow compartment). CXCL12 has a wide range of effects in regards to tumor development but the primary role of CXCL12 appears to be the mobilization of hematopoietic stem cells and the establishment of the cancer stem-like cell niche where high levels of CXCL12 recruit a highly tumorigenic population of tumor cells and promotes cell survival, proliferation, angiogenesis, and metastasis.
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Affiliation(s)
- Jianhua Wang
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, 1011 North University Avenue, Ann Arbor, MI 48109-1078, USA
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18
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Baba M. Recent status of HIV-1 gene expression inhibitors. Antiviral Res 2006; 71:301-6. [PMID: 16488488 DOI: 10.1016/j.antiviral.2006.01.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2005] [Revised: 01/12/2006] [Accepted: 01/13/2006] [Indexed: 11/16/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) gene expression and transcription is a crucial step in the viral replication cycle, which is considered to be a potential target for inhibition of HIV-1. Among the factors involved in this step, the cellular protein nuclear factor (NF)-kappaB is the most powerful inducer of HIV-1 gene expression. On the other hand, the viral protein Tat plays a central role in sustaining a high level of HIV-1 replication. Several compounds have been reported to selectively inhibit the functions of Tat and NF-kappaB. Tat inhibitors target either the Tat/TAR RNA interaction or the Tat cofactor cyclin-dependent kinase 9/cyclin T1. Antioxidants, protein kinase C inhibitors, and IkappaB kinase inhibitors are known to suppress the activation of NF-kappaB. Although some of the compounds inhibit HIV-1 replication in cell cultures at low concentrations, they also have considerable toxicity to the host cells. Considering the increase of treatment failure cases in highly active antiretroviral therapy due to the emergence of multidrug resistance, HIV-1 gene expression inhibitors should be extensively studied as alternative approach to effective anti-HIV-1 chemotherapy.
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Affiliation(s)
- Masanori Baba
- Division of Antiviral Chemotherapy, Center for Chronic Viral Diseases, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan.
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19
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Wan L, Zhang X, Gunaseelan S, Pooyan S, Debrah O, Leibowitz MJ, Rabson AB, Stein S, Sinko PJ. Novel multi-component nanopharmaceuticals derived from poly(ethylene) glycol, retro-inverso-Tat nonapeptide and saquinavir demonstrate combined anti-HIV effects. AIDS Res Ther 2006; 3:12. [PMID: 16635263 PMCID: PMC1481600 DOI: 10.1186/1742-6405-3-12] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Accepted: 04/24/2006] [Indexed: 11/10/2022] Open
Abstract
Background Current anti-AIDS therapeutic agents and treatment regimens can provide a dramatically improved quality of life for HIV-positive people, many of whom have no detectable viral load for prolonged periods of time. Despite this, curing AIDS remains an elusive goal, partially due to the occurrence of drug resistance. Since the development of resistance is linked to, among other things, fluctuating drug levels, our long-term goal has been to develop nanotechnology-based drug delivery systems that can improve therapy by more precisely controlling drug concentrations in target cells. The theme of the current study is to investigate the value of combining AIDS drugs and modifiers of cellular uptake into macromolecular conjugates having novel pharmacological properties. Results Bioconjugates were prepared from different combinations of the approved drug, saquinavir, the antiviral agent, R.I.CK-Tat9, the polymeric carrier, poly(ethylene) glycol and the cell uptake enhancer, biotin. Anti-HIV activities were measured in MT-2 cells, an HTLV-1-transformed human lymphoid cell line, infected with HIV-1 strain Vbu 3, while parallel studies were performed in uninfected cells to determine cellular toxicity. For example, R.I.CK-Tat9 was 60 times more potent than L-Tat9 while the addition of biotin resulted in a prodrug that was 2850 times more potent than L-Tat9. Flow cytometry and confocal microscopy studies suggest that variations in intracellular uptake and intracellular localization, as well as synergistic inhibitory effects of SQV and Tat peptides, contributed to the unexpected and substantial differences in antiviral activity. Conclusion Our results demonstrate that highly potent nanoscale multi-drug conjugates with low non-specific toxicity can be produced by combining moieties with anti-HIV agents for different targets onto macromolecules having improved delivery properties.
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Affiliation(s)
- Li Wan
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers University, 160Frelinghuysen Road, Piscataway, New Jersey 08854-0789, USA
| | - Xiaoping Zhang
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers University, 160Frelinghuysen Road, Piscataway, New Jersey 08854-0789, USA
| | - Simi Gunaseelan
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers University, 160Frelinghuysen Road, Piscataway, New Jersey 08854-0789, USA
| | - Shahriar Pooyan
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers University, 160Frelinghuysen Road, Piscataway, New Jersey 08854-0789, USA
| | - Olivia Debrah
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers University, 160Frelinghuysen Road, Piscataway, New Jersey 08854-0789, USA
| | - Michael J Leibowitz
- Department of Molecular Genetics, Microbiology, and Immunology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854, USA
- Cancer Institute of New Jersey, New Brunswick, New Jersey 08903-2681, USA
| | - Arnold B Rabson
- Department of Molecular Genetics, Microbiology, and Immunology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854, USA
- Cancer Institute of New Jersey, New Brunswick, New Jersey 08903-2681, USA
| | - Stanley Stein
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers University, 160Frelinghuysen Road, Piscataway, New Jersey 08854-0789, USA
- Cancer Institute of New Jersey, New Brunswick, New Jersey 08903-2681, USA
| | - Patrick J Sinko
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers University, 160Frelinghuysen Road, Piscataway, New Jersey 08854-0789, USA
- Cancer Institute of New Jersey, New Brunswick, New Jersey 08903-2681, USA
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20
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Ochsenbauer-Jambor C, Jones J, Heil M, Zammit KP, Kutsch O. T-cell line for HIV drug screening using EGFP as a quantitative marker of HIV-1 replication. Biotechniques 2006; 40:91-100. [PMID: 16454046 DOI: 10.2144/000112072] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The rapid increase of viral strains that are resistant to the currently available antiretroviral drugs is a threat to the success of current human immunodeficiency virus type 1 (HIV-1) treatment and emphasizes the importance of developing novel anti-HIV-1 compounds. To improve the current abilities to screen for novel HIV-1 inhibitors, here we introduce a T-cell-based reporter cell line (JLTRG-RS) that expresses both HIV-1 coreceptors, CXCR4 and CCRS, and provides the convenience of using enhanced green fluorescent protein (EGFP) as a direct and quantitative marker. Unlike previous EGFP-based reporter cell lines, JLTRG-RS cells have an unusually high dynamic signal range, sufficient for plate reader detection using a 384-well format. In this format, JLTRG-R5 cell-based infectivity assays have a Z'-factor of 0.78, which defines the assay as extremely robust and clearly amenable to high-throughput screening. The functional similarity of the JLTRG-R5 cell line and peripheral blood mononuclear cells (PBMCs) was demonstrated through the identity of the inhibitory concentrations, 50% (IC50s) for four antiretroviral compounds or neutralizing antibodies. Because EGFP can be directly and continuously quantified in cell culture, the reporter cell line requires no manipulation during assay preparation or analysis. In addition, the EGFP marker allows for data acquisition at an optimal time point by prescreening selected positive control wells using fluorescent microscopy. These characteristics make the system extremely flexible, rapid, and inexpensive. Due to its intrinsic flexibility, the JLTRG-R5 cell-based reporter system provides a powerful tool to greatly facilitate future screening for HIV-1 inhibitors.
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21
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Abstract
A combination of three or more antiretroviral drugs, commonly termed 'highly active antiretroviral therapy' (HAART), has become the standard-of-care treatment for HIV-related disease in the developed world. Since its initiation in the mid 1990s, HAART has led to substantial reductions in both mortality and morbidity. There are, however, significant problems associated with existing therapies including high pill burdens and serious side effects in many patients, as well as the emergence and transmission of drug-resistant HIV variants. There is, therefore, a need for new medicines to treat HIV infections, both from the existing drug classes and, perhaps more importantly, a need for medicines that act against the virus in entirely new ways. In recent years, much has been learned about how HIV enters its target cells and this work has led to the identification of compounds that potently inhibit the individual steps of viral entry. The status of current research focussed on preventing HIV entry is described below.
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Affiliation(s)
- S Redshaw
- Roche Discovery Welwyn, Welwyn Garden City, Hertfordshire, UK.
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22
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Wang M, Xu Z, Tu P, Yu X, Xiao S, Yang M. Alpha,alpha-trehalose derivatives bearing guanidino groups as inhibitors to HIV-1 Tat-TAR RNA interaction in human cells. Bioorg Med Chem Lett 2004; 14:2585-8. [PMID: 15109657 DOI: 10.1016/j.bmcl.2004.02.073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2004] [Accepted: 02/21/2004] [Indexed: 10/26/2022]
Abstract
Replication of HIV-1 requires specific interactions of Tat protein with TAR RNA. Disruption of Tat-TAR RNA interaction could inhibit HIV-1 replication. Here four target compounds were designed and synthesized to bind to TAR RNA for blocking the interaction of Tat-TAR RNA. The core molecule 6,6'-diamino-6,6'-dideoxy-alpha,alpha-trehalose was obtained from selective bromination of, alpha,alpha-trehalose at C-6,6', followed by acetylation, azide displacement, deacetylation, and reduction. Coupling of the core molecule with the protected amino acid, then deprotection and guanidinylation generated the novel alpha,alpha-trehalose derivatives. Their abilities to inhibit Tat-TAR RNA interaction in human cells were determined by a Tat-dependent HIV-1 LTR-driven CAT assays.
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Affiliation(s)
- Min Wang
- National Research Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100083, PR China
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23
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Huang MB, Jin LL, James CO, Khan M, Powell MD, Bond VC. Characterization of Nef-CXCR4 interactions important for apoptosis induction. J Virol 2004; 78:11084-96. [PMID: 15452229 PMCID: PMC521796 DOI: 10.1128/jvi.78.20.11084-11096.2004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The HIV-1 Nef protein was analyzed for apoptotic structural motifs that interact with the CXCR4 receptor and induce apoptosis in CD4(+) lymphocytes. Two apoptotic motifs were identified. One centered on Nef amino acids (aa) 50 to 60, with the overlapping 20-mer peptides retaining about 82% of the activity of the full Nef protein. The second centered on aa 170 to 180, with the overlapping 20-mer peptides retaining about 30% of the activity of the full protein. Significant apoptotic abilities were observed for 11-mer motif peptides spanning aa 50 to 60 and aa 170 to 180, with a scrambled version of the 11-mer motif peptide corresponding to aa 50 to 60 showing no apoptotic ability. Hallmarks of apoptosis, such as the formation of DNA ladders and caspase activation, that were observed with the full-length protein were equally evident upon exposure of cells to these motif peptides. A CXCR4 antibody and the endogenous ligand SDF-1alpha were effective in blocking Nef peptide-induced apoptosis as well as the physical binding of a fluorescently tagged Nef protein, while CCR5 antibodies were ineffective. The CXCR4-negative cell line MDA-MB-468 was resistant to the apoptotic peptides and became sensitive to the apoptotic peptides upon transfection with a CXCR4-expressing vector. A fluorescently tagged motif peptide and Nef protein displayed physical binding to CXCR4-transfected MDA-MB-468 cells, but not to CCR5-transfected cells. The removal of the apoptotic motif sequences from the full-length protein completely eliminated the ability of Nef to induce apoptosis. However, these modified Nef proteins still retained the ability to enhance viral infectivity. Thus, specific sequences in the Nef protein appear to be necessary for Nef protein-induced apoptosis as well as for physical interaction with CXCR4 receptors.
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Affiliation(s)
- Ming-Bo Huang
- Department of Microbiology, Biochemistry, and Immunology, Morehouse School of Medicine, 720 Westview Drive S.W., Atlanta, GA 30310, USA
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24
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Zhou N, Fang J, Mukhtar M, Acheampong E, Pomerantz RJ. Inhibition of HIV-1 fusion with small interfering RNAs targeting the chemokine coreceptor CXCR4. Gene Ther 2004; 11:1703-12. [PMID: 15306840 DOI: 10.1038/sj.gt.3302339] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
RNA interference (RNAi) is an evolutionarily conserved process by which plants and animals protect their genomes utilizing small, double-stranded RNAs to degrade target RNAs in a sequence-specific manner. Post-transcriptional gene silencing by these moieties can lead to degradation of both cellular and viral RNAs. It has recently been shown that double-stranded, small interfering RNAs (siRNAs) of 21-25 nucleotides can be transfected into relevant cells to target specific RNAs. This approach was utilized to inhibit human immunodeficiency virus type I (HIV-1) infection in human cells. siRNAs with homology to a motif in the mRNA that encodes for the HIV-1 chemokine coreceptor CXCR4 was utilized. Complementary studies via immunofluorescence microscopy and fluorescence-activated cell sorting demonstrated downregulation of CXCR4 from the surface of cells transfected with the specific siRNAs. As well, siRNAs without sequence homology to CXCR4 were used as controls and demonstrated no downregulation of CXCR4. siRNAs targeted to another chemokine coreceptor, APJ, showed specificity for downregulation of APJ but had no effects on CXCR4. Transfections with siRNAs targeting CXCR4 mRNA were shown to inhibit HIV-1 envelope fusion, which is relatively resistant to most viral inhibitors targeting chemokine coreceptors. The specificity of this effect was demonstrated by the inhibition of fusion by CXCR4-tropic and dual-tropic (CXCR4 and CCR5) envelope glycoproteins from HIV-1 on CXCR4+ indicator cells, but the lack of effects by siRNAs targeting CXCR4 mRNA on dual-tropic HIV-1 envelopes in CCR5+ indicator cells utilizing these fusion assays. Interestingly, siRNAs targeting CXCR4 selectively inhibited CXCR4-tropic cell-free virus infection of human cells but at only modest levels as compared to cell:cell fusion. siRNA may be a potential molecular therapeutic approach to alter a cellular cofactor critical for infection of human cells by relevant strains of HIV-1. The targeting of a cellular cofactor, rather than the HIV-1-specific mRNAs or genomic RNA, holds promise as the rapid mutational ability of the HIV-1 genome may obviate the potential clinical use of RNAi directly against this virus.
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Affiliation(s)
- N Zhou
- Division of Infectious Diseases and Environmental Medicine, Department of Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
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25
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Zhou N, Zhang X, Fan X, Argyris E, Fang J, Acheampong E, DuBois GC, Pomerantz RJ. The N-terminal domain of APJ, a CNS-based coreceptor for HIV-1, is essential for its receptor function and coreceptor activity. Virology 2003; 317:84-94. [PMID: 14675627 DOI: 10.1016/j.virol.2003.08.026] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The human APJ, a G protein-coupled seven-transmembrane receptor, has been found to be dramatically expressed in the human central nervous system (CNS) and also to serve as a coreceptor for the entry of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV). Studies with animal models suggested that APJ and its natural ligand, apelin, play an important role in the central control of body fluid homeostasis, and in regulation of blood pressure and cardiac contractility. In this study, we characterize the structural and functional determinants of the N-terminal domain of APJ in interactions with its natural ligand and HIV-1 envelope glycoprotein. We demonstrate that the second 10 residues of the N-terminal domain of APJ are critical for association with apelin, while the first 20 amino acids play an important role in supporting cell-cell fusion mediated by HIV-1 gp120. With site-directed mutagenesis, we have identified that the negatively charged amino acid residues Glu20 and Asp23 are involved in receptor and coreceptor functions, but residues Tyr10 and Tyr11 substantially contribute to coreceptor function for both T-tropic (CXCR4) and dual-tropic (CXCR4 and CCR5) HIV-1 isolates. Thus, this study provides potentially important information for further characterizing APJ-apelin functions in vitro and in vivo and designing small molecules for treatment of HIV-1 infection in the CNS.
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Affiliation(s)
- Naiming Zhou
- Dorrance H. Hamilton Laboratories, Center for Human Virology and Biodefense, Division of Infectious Diseases and Environmental Medicine, Department of Medicine, Jefferson Medical College, Philadelphia, PA 19107, USA
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26
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Borkow G, Vijayabaskar V, Lara HH, Kalinkovich A, Lapidot A. Structure–activity relationship of neomycin, paromomycin, and neamine–arginine conjugates, targeting HIV-1 gp120–CXCR4 binding step. Antiviral Res 2003; 60:181-92. [PMID: 14638394 DOI: 10.1016/s0166-3542(03)00156-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We have recently designed and synthesized aminoglycoside-arginine conjugates (AACs) as potential anti-HIV-1 agents. AACs exert a number of activities related to Tat antagonism. We here present a new set of AACs, conjugates of neomycin B, paromomycin, and neamine with different number of arginines (1-6), their (a) uptake by human T-cell lines, (b) antiviral activities, (c) competition with monoclonal antibody (mAb) 12G5 binding to CXCR4, (d) competition with stromal cell-derived factor-1 (SDF-1alpha) binding to CXCR4, and (e) competition with HIV-1 coat protein gp120 cell penetration. The appearance of mutations in HIV-1 gp120 gene in AACs resistant HIV-1 isolates, supports that AACs inhibit HIV-1 infectivity via interference of gp120-CXCR4 interaction. Our results point that the most potent AACs is the hexa-arginine-neomycin conjugate, the other multi-arginine-aminoglycoside conjugates are less active, and the mono-arginine conjugates display the lowest activity. Our studies demonstrate that, in addition to the core, the number of arginines attached to a specific aminoglycoside, are also important in the design of potent anti-HIV agents. The AACs play an important role, not only as HIV-1 RNA binders but also as inhibitors of viral entry into human cells.
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Affiliation(s)
- Gadi Borkow
- Department of Organic Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel
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27
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Zhou N, Fang J, Acheampong E, Mukhtar M, Pomerantz RJ. Binding of ALX40-4C to APJ, a CNS-based receptor, inhibits its utilization as a co-receptor by HIV-1. Virology 2003; 312:196-203. [PMID: 12890632 DOI: 10.1016/s0042-6822(03)00185-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
APJ, a G protein-coupled seven-transmembrane receptor, has been shown to serve as a co-receptor for the entry of human immunodeficiency virus type 1 (HIV-1), and it is dramatically expressed in central nervous system (CNS)-based cells. ALX40-4C was identified as a small-molecule antagonist of the chemokine receptor CXCR4, which can specifically inhibit HIV-1 entry via this co-receptor. In this study, we demonstrated that ALX40-4C inhibited both APJ- and CXCR4/APJ-mediated cell membrane fusion in a dose-dependent manner. In competitive binding assays, (125)I-Apelin13 was replaced by ALX40-4C with an IC(50) of 2.9 microM, as compared with an IC(50) of 0.2 nM for Apelin13. Furthermore, ALX40-4C could block ligand-induced APJ internalization and signaling. ALX40-4C, as an antagonist to APJ, directly binds to and prevents use of APJ as a HIV-1 co-receptor. Thus, ALX-4C has potential utility for further elucidation of HIV-1 neuropathogenesis and therapy of HIV-1-induced encephalopathy.
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Affiliation(s)
- Naiming Zhou
- The Dorrance H. Hamilton Laboratories, Thomas Jefferson University, Jefferson Medical College, Center for Human Virology, Division of Infectious Diseases, Department of Medicine, 1020 Locust Street, Suite 329, Philadelphia, PA 19107, USA
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28
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Booth V, Slupsky CM, Clark-Lewis I, Sykes BD. Unmasking ligand binding motifs: identification of a chemokine receptor motif by NMR studies of antagonist peptides. J Mol Biol 2003; 327:329-34. [PMID: 12628240 DOI: 10.1016/s0022-2836(03)00094-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Determining the critical structural features a ligand must possess in order to bind to its receptor is of key importance to the understanding of vital biological processes and to the rational design of small molecule therapeutics to modulate receptor function. We have developed a general strategy for determining such ligand binding motifs using low temperature NMR structures of peptides with the desired receptor binding properties. This approach has been successfully applied to determine a binding motif for the chemokine receptor CXCR4. The motif identified provides a detailed guide for the design of small molecule antagonists against CXCR4, which are much sought after to aid in the treatment of a number of conditions including human immunodeficiency virus type 1 infection and a variety of cancers.
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Affiliation(s)
- Valerie Booth
- Department of Biochemistry, Protein Engineering Network of Centres of Excellence, University of Alberta, 713 HMRC Edmonton, Alta., Canada T5G 2S2
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29
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Abstract
Defining the mechanisms of HIV-1 entry has enabled the rational design of strategies aimed at interfering with the process. This article delineates what is currently understood about HIV-1 entry, as a window through which to understand what will likely be the next major group of antiretroviral therapeutics. These exciting new approaches offer the promise of adding viral entry to reverse transcription and protein processing as steps to block in the viral life cycle. Several principles learned with other antiretroviral drugs are sure to be valid for entry antagonists, whereas other considerations may be unique to this group of agents. There is no agent to which HIV-1 has not been able to acquire resistance and this is likely to remain the case. Multiple rounds of viral replication are required to generate the genetic diversity that forms the basis of resistance. Combination therapy in which replication is maximally suppressed will remain a cornerstone of treatment with entry inhibitors, as with other agents. Furthermore, the coreceptor specificity of some entry and fusion inhibitors argues that combinations will likely be needed to broaden the effective range of susceptible viral variants. Finally, the targeting of multiple steps within the entry process has the potential for synergy. The fusion inhibitor T20 and CXCR4 antagonist AMD3100 are synergistic in vitro at blocking infection of PBMC with clinical isolates [115] and T20 combined with the CD4 inhibitor PRO 542 have synergistic in vitro effects, with more than 10-fold greater inhibition of R5, X4, and R5X4 strains than either agent alone [116]. Entry antagonists raise other, unique issues. As discussed previously, the theoretic concern exists that blocking CCR5 could enhance the emergence of CXCR4-using variants and possibly accelerate disease. So far, in vitro selection for variants resistant to the CCR5 antagonist SCH-C in PBMC (which express both CCR5 and CXCR4) has resulted in mutants that were resistant to the blocker but still used CCR5. Alternatively, because many HIV-1 strains have the capacity to use several other chemokine or orphan receptors for entry, blocking both CCR5 and CXCR could lead to a variant that uses one of these other molecules in place of the principal coreceptors, although data in vitro so far suggest that this is unlikely [13,14]. This new class of antiviral drugs offers great promise but also novel concerns, and careful analysis of viruses that arise with their use in vivo is essential.
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Affiliation(s)
- Linda D Starr-Spires
- Pulmonary, Allergy and Critical Care Division, University of Pennsylvania School of Medicine, 522 Johnson Pavilion, 36th and Hamilton Walk, Philadelphia, PA 19104-6060, USA
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30
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Said EA, Krust B, Nisole S, Svab J, Briand JP, Hovanessian AG. The anti-HIV cytokine midkine binds the cell surface-expressed nucleolin as a low affinity receptor. J Biol Chem 2002; 277:37492-502. [PMID: 12147681 DOI: 10.1074/jbc.m201194200] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The growth factor midkine (MK) is a cytokine that inhibits the attachment of human immunodeficiency virus particles by a mechanism similar to the nucleolin binding HB-19 pseudopeptide. Here we show that the binding of MK to cells occurs specifically at a high and a low affinity binding site. HB-19 prevents the binding of MK to the low affinity binding site only. Confocal immunofluorescence laser microscopy revealed the colocalization of MK and the cell-surface-expressed nucleolin at distinct spots. The use of various deletion constructs of nucleolin then indicated that the extreme C-terminal end of nucleolin, containing repeats of the amino acid motif RGG, is the domain that binds MK. The specific binding of MK to cells is independent of heparan sulfate and chondroitin sulfate expression. After binding to cells, MK enters cells by an active process. Interestingly, the cross-linking of surface-bound MK with a specific antibody results in the clustering of surface nucleolin along with glycosylphosphatidylinositol-linked proteins CD90 and CD59, thus, pointing out that MK binding induces lateral assemblies of nucleolin with specific membrane components of lipid rafts. Our results suggest that the cell surface-expressed nucleolin serves as a low affinity receptor for MK and could be implicated in its entry process.
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Affiliation(s)
- Elias A Said
- Unité de Virologie et Immunologie Cellulaire (URA 1930 CNRS), Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France
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31
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Martín-García J, Kolson DL, González-Scarano F. Chemokine receptors in the brain: their role in HIV infection and pathogenesis. AIDS 2002; 16:1709-30. [PMID: 12218382 DOI: 10.1097/00002030-200209060-00003] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Julio Martín-García
- Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
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32
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Abstract
The human immunodeficiency virus (HIV) infects a wide range of human cells. Cell entry is mediated through the CD4 receptor and a variety of coreceptors, most importantly the chemokine receptors CCR5 and CXCR4. Some antiretroviral agents selectively inhibit different HIV phenotypes depending on their coreceptor usage. Here, we analyse mathematical models, which describe the in vivo interaction of HIV phenotypes, differing in their coreceptor usage, with two target cell types (naive and memory CD4+ T cells). In particular, we investigate how the selection pressures on CCR5- and CXCR4-using HIV variants change as a result of treatment with coreceptor-specific antiretroviral agents. Our main result is that CXCR4 inhibitors increase the selection pressure in favor of the emergence of CCR5-using variants, thus selecting for coexistence of CXCR4- and CCR5-using variants, whereas CCR5 inhibitors increase the selection pressure against CCR5-using variants, thus selecting against coexistence. These results shed new light on the potential risks and benefits of coreceptor inhibitors.
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Affiliation(s)
- Roland Regoes
- Ecology and Evolution, Swiss Federal Institute of Technology Zurich, ETH Zentrum NW, CH-8092, Zurich, Switzerland
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33
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Abstract
Chemokines are the largest family of cytokines in human immunophysiology. These proteins are defined by four invariant cysteines and are categorized based on the sequence around the first two cysteines, which leads to two major and two minor subfamilies. Chemokines function by activating specific G protein-coupled receptors, which results in, among other functions, the migration of inflammatory and noninflammatory cells to the appropriate tissues or compartments within tissues. Some of these proteins and receptors have been implicated or shown to be involved in inflammation, autoimmune diseases, and infection by HIV-1. The three-dimensional structure of each monomer is virtually identical, but the quaternary structure of chemokines is different for each subfamily. Structure-function studies reveal several regions of chemokines to be involved in function, with the N-terminal region playing a dominant role. A number of proteins and small-molecule antagonists have been identified that inhibit chemokine activities. In this review, we discuss aspects of the structure, function, and inhibition of chemokines.
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Affiliation(s)
- Elias J Fernandez
- Department of Pharmacology, Yale University, New Haven, Connecticut 06520-8066, USA.
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34
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Kaushik N, Basu A, Palumbo P, Myers RL, Pandey VN. Anti-TAR polyamide nucleotide analog conjugated with a membrane-permeating peptide inhibits human immunodeficiency virus type 1 production. J Virol 2002; 76:3881-91. [PMID: 11907228 PMCID: PMC136084 DOI: 10.1128/jvi.76.8.3881-3891.2002] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The emergence of drug-resistant variants has posed a significant setback against effective antiviral treatment for human immunodeficiency virus (HIV) infections. The choice of a nonmutable region of the viral genome such as the conserved transactivation response element (TAR element) in the 5' long terminal repeat (LTR) may potentially be an effective target for drug development. We have earlier demonstrated that a polyamide nucleotide analog (PNA) targeted to the TAR hairpin element, when transfected into cells, can effectively inhibit Tat-mediated transactivation of HIV type 1 (HIV-1) LTR (T. Mayhood et al., Biochemistry 39:11532-11539, 2000). Here we show that this anti-TAR PNA (PNA(TAR)), upon conjugation with a membrane-permeating peptide vector (transportan) retained its affinity for TAR in vitro similar to the unconjugated analog. The conjugate was efficiently internalized into the cells when added to the culture medium. Examination of the functional efficacy of the PNA(TAR)-transportan conjugate in cell culture using luciferase reporter gene constructs resulted in a significant inhibition of Tat-mediated transactivation of HIV-1 LTR. Furthermore, PNA(TAR)-transportan conjugate substantially inhibited HIV-1 production in chronically HIV-1-infected H9 cells. The mechanism of this inhibition appeared to be regulated at the level of transcription. These results demonstrate the efficacy of PNA(TAR)-transportan as a potential anti-HIV agent.
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Affiliation(s)
- Neerja Kaushik
- Center for the Study of Emerging and Re-Emerging Pathogens, UMDNJ-New Jersey Medical School, Newark, New Jersey 07103, USA
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35
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Cabrera C, Gutiérrez A, Barretina J, Blanco J, Litovchick A, Lapidot A, Clotet B, Esté JA. Anti-HIV activity of a novel aminoglycoside-arginine conjugate. Antiviral Res 2002; 53:1-8. [PMID: 11684311 DOI: 10.1016/s0166-3542(01)00188-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We have previously described conjugates of L-arginine with aminoglycosides (AAC) that have shown anti-human immunodeficiency virus type 1 (HIV-1) activity in in vitro cell culture systems. Here, we extend our report to a novel neomycin B-arginine conjugate (NeoR) that has shown up to 30-fold increased potency over previous AAC compounds. NeoR inhibited the replication of both R5 and X4 strains of HIV-1 in cells expressing the appropriate coreceptor or peripheral blood mononuclear cells. In lymphoid tissue ex vivo, NeoR blocked the replication of the dualtropic strain 89.6 suggesting anti-HIV activity of AAC on the site of in vivo virus replication. NeoR blocked the binding of HIV particles to lymphoid cells and was also able to antagonize the activity of the CXCR4 receptor so it may prevent the emergence of X4 HIV-1 strains. Nevertheless, in a cellular assay, we were unable to detect anti-Tat dependent transactivation activity as previously suggested for this family of compounds.
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Affiliation(s)
- Cecilia Cabrera
- Retrovirology Laboratory, Fundació irsiCaixa, Hospital Universitari Germans Trias i Pujol, Universitat Autonoma de Barcelona, 08916, Badalona, Spain
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36
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Derdeyn CA, Decker JM, Sfakianos JN, Zhang Z, O'Brien WA, Ratner L, Shaw GM, Hunter E. Sensitivity of human immunodeficiency virus type 1 to fusion inhibitors targeted to the gp41 first heptad repeat involves distinct regions of gp41 and is consistently modulated by gp120 interactions with the coreceptor. J Virol 2001; 75:8605-14. [PMID: 11507206 PMCID: PMC115106 DOI: 10.1128/jvi.75.18.8605-8614.2001] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
T-20 is a synthetic peptide that corresponds to 36 amino acids within the C-terminal heptad repeat region (HR2) of human immunodeficiency virus type 1 (HIV-1) gp41. T-20 has been shown to potently inhibit viral replication of HIV-1 both in vitro and in vivo and is currently being evaluated in a Phase III clinical trial. T-649 is an inhibitory peptide that also corresponds to 36 amino acids within HR2. This sequence overlaps the T-20 sequence but is shifted 10 residues toward the N terminus of gp41. Both inhibitors are thought to exert their antiviral activity by interfering with the conformational changes that occur within gp41 to promote membrane fusion following gp120 interactions with CD4 and coreceptor molecules. We have shown previously that coreceptor specificity defined by the V3 loop of gp120 modulates sensitivity to T-20 and that a critical region within the N-terminal heptad repeat (HR1) of gp41 is the major determinant of sensitivity (C. A. Derdeyn et al., J. Virol. 74:8358-8367, 2000). This report shows that (i) regions within gp41 distinct from those associated with T-20 sensitivity govern the baseline sensitivity to T-649 and (ii) T-649 sensitivity of chimeric viruses that contain sequences derived from CXCR4- and CCR5-specific envelopes is also modulated by coreceptor specificity. Moreover, the pattern of sensitivity of CCR5-specific chimeras with only minor differences in their V3 loop was consistent for both inhibitors, suggesting that the individual affinity for coreceptor may influence accessibility of these inhibitors to their target sequence. Finally, an analysis of the sensitivity of 55 primary, inhibitor-naive HIV-1 isolates found that higher concentrations of T-20 (P < 0.001) and T-649 (P = 0.016) were required to inhibit CCR5-specific viruses compared to viruses that utilize CXCR4. The results presented here implicate gp120-coreceptor interactions in driving the complex conformational changes that occur in gp41 to promote fusion and entry and suggest that sensitivity to different HR1-directed fusion inhibitors is governed by distinct regions of gp41 but is consistently modulated by coreceptor specificity.
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Affiliation(s)
- C A Derdeyn
- Department of Microbiology, Birmingham, Alabama 35294, USA
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37
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Affiliation(s)
- Tatjana Dragic
- Albert Einstein College of Medicine, Department of Microbiology and Immunology, 1300 Morris Park Ave, Bronx, NY 10461, USA1
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38
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Doranz BJ, Filion LG, Diaz-Mitoma F, Sitar DS, Sahai J, Baribaud F, Orsini MJ, Benovic JL, Cameron W, Doms RW. Safe use of the CXCR4 inhibitor ALX40-4C in humans. AIDS Res Hum Retroviruses 2001; 17:475-86. [PMID: 11350661 DOI: 10.1089/08892220151126508] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
ALX40-4C is a small peptide inhibitor of the chemokine receptor CXCR4 that can inhibit X4 strains of HIV-1. Prior to the discovery of chemokine receptors as the HIV coreceptors, ALX40-4C was used in phase I/II clinical trials to evaluate its therapeutic potential against HIV-1, making ALX40-4C the first anticoreceptor inhibitor to be tested in humans against HIV-1. Patients in the highest dose groups achieved ALX40-4C levels above the effective concentration of the drug for nearly the entire 1-month treatment period. ALX40-4C was well tolerated by 39 of 40 asymptomatic HIV-infected patients, despite the critical role of CXCR4 in normal development and hematopoiesis. No significant or consistent reductions in viral load were observed, but only 12 of the enrolled patients harbored virus types that used CXCR4. We also found that ALX40-4C interacts with the second extracellular loop of CXCR4 and inhibits infection exclusively by blocking direct virus-CXCR4 interactions.
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Affiliation(s)
- B J Doranz
- Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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39
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Gatignol A, Jeang KT. Tat as a transcriptional activator and a potential therapeutic target for HIV-1. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2001; 48:209-27. [PMID: 10987092 DOI: 10.1016/s1054-3589(00)48007-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- A Gatignol
- U529 INSERM, Institut Cochin de Génétique Moléculaire, Paris, France
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40
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Mayhood T, Kaushik N, Pandey PK, Kashanchi F, Deng L, Pandey VN. Inhibition of Tat-mediated transactivation of HIV-1 LTR transcription by polyamide nucleic acid targeted to TAR hairpin element. Biochemistry 2000; 39:11532-9. [PMID: 10995220 DOI: 10.1021/bi000708q] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tat, an essential human immunodeficiency virus type 1 protein interacts with the transactivation response element (TAR) and stimulates transcription from the viral long-terminal repeat (LTR). Blockage of Tat-TAR interaction halts viral transcription and hence replication. We have found that polyamide nucleic acid (PNA), targeted to the TAR sequences of viral RNA genome is able to prevent Tat-TAR interaction by efficient sequestration of the TAR. Anti-TAR PNA competes for TAR and prevents Tat-mediated stimulation of HIV-1 LTR transcription in vitro but has no influence on the basal level of transcription in the absence of Tat. Using a reporter gene construct pHIV LTR-CAT and pCMV-Tat in cell culture, we have further shown that anti-TAR PNA is able to block Tat-mediated transactivation of HIV-1 LTR transcription in vivo as judged by the extent of LTR driven CAT gene expression in the absence and presence of anti-TAR PNA. Supplementation of 100 nM of anti-TAR PNA into the culture medium further enhances the suppression of transactivation. Nonspecific scrambled PNA had no influence on Tat-TAR interaction and LTR-driven CAT gene expression in cell culture. These results suggest that PNA targeted to the TAR sequence of the viral genome may be a potential inhibitor of HIV-1 gene expression.
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Affiliation(s)
- T Mayhood
- Department of Biochemistry and Molecular Biology, UMD-New Jersey Medical School, 185 South Orange Avenue, Newark, New Jersey 07103, USA
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41
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Derdeyn CA, Decker JM, Sfakianos JN, Wu X, O'Brien WA, Ratner L, Kappes JC, Shaw GM, Hunter E. Sensitivity of human immunodeficiency virus type 1 to the fusion inhibitor T-20 is modulated by coreceptor specificity defined by the V3 loop of gp120. J Virol 2000; 74:8358-67. [PMID: 10954535 PMCID: PMC116346 DOI: 10.1128/jvi.74.18.8358-8367.2000] [Citation(s) in RCA: 629] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
T-20 is a synthetic peptide that potently inhibits replication of human immunodeficiency virus type 1 by interfering with the transition of the transmembrane protein, gp41, to a fusion active state following interactions of the surface glycoprotein, gp120, with CD4 and coreceptor molecules displayed on the target cell surface. Although T-20 is postulated to interact with an N-terminal heptad repeat within gp41 in a trans-dominant manner, we show here that sensitivity to T-20 is strongly influenced by coreceptor specificity. When 14 T-20-naive primary isolates were analyzed for sensitivity to T-20, the mean 50% inhibitory concentration (IC(50)) for isolates that utilize CCR5 for entry (R5 viruses) was 0.8 log(10) higher than the mean IC(50) for CXCR4 (X4) isolates (P = 0. 0055). Using NL4.3-based envelope chimeras that contain combinations of envelope sequences derived from R5 and X4 viruses, we found that determinants of coreceptor specificity contained within the gp120 V3 loop modulate this sensitivity to T-20. The IC(50) for all chimeric envelope viruses containing R5 V3 sequences was 0.6 to 0.8 log(10) higher than that for viruses containing X4 V3 sequences. In addition, we confirmed that the N-terminal heptad repeat of gp41 determines the baseline sensitivity to T-20 and that the IC(50) for viruses containing GIV at amino acid residues 36 to 38 was 1.0 log(10) lower than the IC(50) for viruses containing a G-to-D substitution. The results of this study show that gp120-coreceptor interactions and the gp41 N-terminal heptad repeat independently contribute to sensitivity to T-20. These results have important implications for the therapeutic uses of T-20 as well as for unraveling the complex mechanisms of virus fusion and entry.
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Affiliation(s)
- C A Derdeyn
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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42
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Li BQ, Fu T, Gong WH, Dunlop N, Kung H, Yan Y, Kang J, Wang JM. The flavonoid baicalin exhibits anti-inflammatory activity by binding to chemokines. IMMUNOPHARMACOLOGY 2000; 49:295-306. [PMID: 10996027 DOI: 10.1016/s0162-3109(00)00244-7] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Baicalin (BA) is a flavonoid compound purified from the medicinal plant Scutellaria baicalensis Georgi and has been reported to possess anti-inflammatory and anti-viral activities. In order to elucidate the mechanism(s) of action of BA, we tested whether BA could interfere with chemokines or chemokine receptors, which are critical mediators of inflammation and infection. We observed that BA inhibited the binding of a number of chemokines to human leukocytes or cells transfected to express specific chemokine receptors. This was associated with a reduced capacity of the chemokines to induce cell migration. Co-injection of BA with CXC chemokine interleukin-8 (IL-8) into rat skin significantly inhibited IL-8 elicited neutrophil infiltration. BA did not directly compete with chemokines for binding to receptors, but rather acted through its selective binding to chemokine ligands. This conclusion was supported by the fact that BA cross-linked to oxime resin bound chemokines of the CXC (stromal cell-derived factor (SDF)-1alpha, IL-8), CC (macrophage inflammatory protein (MIP)-1beta, monocyte chemotactic protein (MCP)-2), and C (lymphotactin (Ltn)) subfamilies. BA did not interact with CX3C chemokine fractalkine/neurotactin or other cytokines, such as TNF-alpha and IFN-gamma, indicating that its action is selective. These results suggest that one possible anti-inflammatory mechanism of BA is to bind a variety of chemokines and limit their biological function.
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Affiliation(s)
- B Q Li
- Intramural Research Support Program, SAIC Frederick, National Cancer Institute-Frederick Cancer Research and Development Center, Building 560, Room 31-40, Frederick, MD 21702-1201, USA.
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43
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Cabrera C, Gutiérrez A, Blanco J, Barretina J, Litovchick A, Lapidot A, Evdokimov AG, Clotet B, Esté JA. Anti-human immunodeficiency virus activity of novel aminoglycoside-arginine conjugates at early stages of infection. AIDS Res Hum Retroviruses 2000; 16:627-34. [PMID: 10791873 DOI: 10.1089/088922200308855] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Conjugates of L-arginine with aminoglycosides have already been described as potent in vitro inhibitors of the HIV-1 Tat-trans-activation responsive element interaction. The polycationic nature of these agents leads us to suggest that they may be active against HIV-1 replication by inhibiting earlier stages of the virus life cycle. We have found that R4K and R3G, kanamycin A, and gentamicin C, conjugated with arginine, inhibited HIV-1 NL4-3 replication at EC50 values of 15 and 30 microM for R3G and R4K, respectively, without a detectable tonic effect on MT-4 cells at concentrations higher than 4000 and about 1000 microM, respectively. Both compounds inhibited the binding of a monoclonal antibody (12G5) directed to CXCR4 as well as the intracellular Ca2+ signal induced by the chemokine SDF-1alpha on CXCR4+ cells, suggesting that aminoglycoside-arginine conjugates interact with CXCR4, the coreceptor used by T-tropic, X4 strains of HIV-1. On the other hand, CB4K, a conjugate of kanamycin A with gamma-guanidinobutyric acid, structurally similar to R4K, failed to display any anti-HIV activity of CXCR4 antagonist activity. An HIV-1 strain that was made resistant to the known CXCR4 antagonist AMD3100 was cross-resistant to both R4K and R3G. However, unlike SDF-1alpha and R4K, R3G inhibited the binding of HIV-1 to MT-4 cells. Aminoglycoside-arginine conjugates inhibit HIV replication by interrupting the early phase of the virus life cycle, namely virus binding to CD4 cells and interaction with CXCR4. R3G and R4K may serve as prototypes of novel anti-HIV agents and should be further studied.
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Affiliation(s)
- C Cabrera
- Institut de Recerca de la SIDA-Caixa (irsiCaixa), Retrovirology Laboratory, Hospital Universitari Germans Trias i Pujol, Badalona, Spain
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44
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Klimkait T, Felder ER, Albrecht G, Hamy F. Rational optimization of a HIV-1 Tat inhibitor: Rapid progress on combinatorial lead structures. Biotechnol Bioeng 2000. [DOI: 10.1002/(sici)1097-0290(1998)61:3%3c155::aid-cc3%3e3.0.co;2-g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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45
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Litovchick A, Evdokimov AG, Lapidot A. Aminoglycoside-arginine conjugates that bind TAR RNA: synthesis, characterization, and antiviral activity. Biochemistry 2000; 39:2838-52. [PMID: 10715103 DOI: 10.1021/bi9917885] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Regulation of HIV gene expression is crucially dependent on binding of the trans-activator protein, Tat, to the trans-activation response RNA element, TAR, found at the 5' end of all HIV-1 transcripts. Tat-TAR interaction is mediated by a short arginine-rich domain of the protein. Disruption of this interaction could, in theory, create a state of complete viral latency. A new class of small-molecule peptidomimetic TAR RNA binders, conjugates of aminoglycosides and arginine, was recently designed [Litovchick, A., Evdokimov, A. G., and Lapidot, A. (1999) FEBS Lett. 445, 73-79]. Two of these compounds, the tri-arginine derivative of gentamicin C (R3G) and the tetra-arginine derivative of kanamycin A (R4K), bind efficiently and specifically to TAR RNA. These compounds display negligible toxicity while being transported and accumulated in cell nuclei. Here we present a detailed synthesis and chemical characterization of the aminoglycoside-arginine conjugates R3G and R4K as well as GB4K, the tetra-gamma-guanidinobutyric derivative of kanamycin A. Their binding sites on TAR RNA were assigned by RNase A, uranyl nitrate, and lead acetate footprinting. The conjugates interact with TAR RNA in the widened major groove, formed by the UCU bulge and the neighboring base pairs of the upper stem portion of TAR, the binding site of Tat protein, and Tat-derived peptides (e.g., R52). Our results suggest an additional binding site of R4K and R3G compounds, in the lower stem-bulge region of TAR. The antiviral activity of the conjugates in cultured equine dermal fibroblasts infected with equine infectious anemia virus, used as a model system of HIV-infected cells, is also presented.
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Affiliation(s)
- A Litovchick
- Departments of Organic Chemistry and Structural Biology, The Weizmann Institute of Science, 76100 Rehovot, Israel
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46
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Romerio F, Gallo RC. Novel biologic approaches for the treatment of AIDS. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1999; 134:577-84. [PMID: 10595784 DOI: 10.1016/s0022-2143(99)90096-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- F Romerio
- Institute of Human Virology, University of Maryland Biotechnology Institute, Baltimore 21201, USA
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47
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Klimkait T, Felder ER, Albrecht G, Hamy F. Rational optimization of a HIV-1 Tat inhibitor: rapid progress on combinatorial lead structures. Biotechnol Bioeng 1999; 61:155-68. [PMID: 10397803 DOI: 10.1002/(sici)1097-0290(1998)61:3<155::aid-cc3>3.0.co;2-g] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Lead molecules identified by combinatorial chemistry approaches are preferred starting points for straightforward improvements of compound profiles. Structure-guided rationales can be supported and complemented by systematic variations based on the modular nature of the molecules. A peptoidic compound (CGP 64222), previously identified from a sequential unrandomization process, was shown to specifically inhibit the interaction between the HIV-1 trans-activator Tat and its RNA response element TAR. To improve the compound's pharmaceutical attractiveness an approach to reduce both, size and number of charges was pursued. Because this resulted in activity decrease, parallel synthesis with variations on one rationally defined position aimed at the identification of structural determinants was undertaken to regain in vitro activity in biochemical and cellular Tat-TAR interaction assays. As a result CGP74026 was identified, a drastically simplified but highly active Tat antagonist, which is able to block HIV-1 replication even in primary human cells.
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Affiliation(s)
- T Klimkait
- Institute for Medical Microbiology, University of Basel, Basel, Switzerland
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48
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Doranz BJ, Orsini MJ, Turner JD, Hoffman TL, Berson JF, Hoxie JA, Peiper SC, Brass LF, Doms RW. Identification of CXCR4 domains that support coreceptor and chemokine receptor functions. J Virol 1999; 73:2752-61. [PMID: 10074122 PMCID: PMC104032 DOI: 10.1128/jvi.73.4.2752-2761.1999] [Citation(s) in RCA: 184] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interaction of the chemokine stromal cell-derived factor 1 (SDF-1) with its receptor CXCR4 is vital for cell trafficking during development, is capable of inhibiting human immunodeficiency virus type 1 (HIV-1) utilization of CXCR4 as a coreceptor, and has been implicated in delaying disease progression to AIDS in vivo. Because of the importance of this chemokine-chemokine receptor pair to both development and disease, we investigated the molecular basis of the interaction between CXCR4 and its ligands SDF-1 and HIV-1 envelope. Using CXCR4 chimeras and mutants, we determined that SDF-1 requires the CXCR4 amino terminus for binding and activates downstream signaling pathways by interacting with the second extracellular loop of CXCR4. SDF-1-mediated activation of CXCR4 required the Asp-Arg-Tyr motif in the second intracellular loop of CXCR4, was pertussis toxin sensitive, and did not require the distal C-terminal tail of CXCR4. Several CXCR4 mutants that were not capable of binding SDF-1 or signaling still supported HIV-1 infection, indicating that the ability of CXCR4 to function as a coreceptor is independent of its ability to signal. Direct binding studies using the X4 gp120s HXB, BH8, and MN demonstrated the ability of HIV-1 gp120 to bind directly and specifically to the chemokine receptor CXCR4 in a CD4-dependent manner, using a conformationally complex structure on CXCR4. Several CXCR4 variants that did not support binding of soluble gp120 could still function as viral coreceptors, indicating that detectable binding of monomeric gp120 is not always predictive of coreceptor function.
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Affiliation(s)
- B J Doranz
- Department of Pathology and Laboratory Medicine, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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49
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Cammack N. Human immunodeficiency virus type 1 entry and chemokine receptors: a new therapeutic target. Antivir Chem Chemother 1999; 10:53-62. [PMID: 10335399 DOI: 10.1177/095632029901000201] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
After the identification of CD4 as the primary receptor for human immunodeficiency virus (HIV) type 1 entry into cells of the immune system, it soon became clear that CD4 alone was not sufficient to establish a productive infection. The search for the second receptors or co-receptors started over 10 years ago, and it was not until 1996 that G protein-coupled 7-transmembrane receptors, CXCR4 and CCR5 were finally identified as the co-receptors for HIV-1 entry. The 7-transmembrane receptor family is a familiar therapeutic target for a number of diseases, and therefore these recent findings represent an exciting opportunity for new therapeutic approaches to the treatment of HIV-1 infection.
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Affiliation(s)
- N Cammack
- Department of Virology, Roche Discovery Welwyn, Welwyn Garden City, UK
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50
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Litovchick A, Evdokimov AG, Lapidot A. Arginine-aminoglycoside conjugates that bind to HIV transactivation responsive element RNA in vitro. FEBS Lett 1999; 445:73-9. [PMID: 10069377 DOI: 10.1016/s0014-5793(99)00092-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
HIV gene expression is crucially dependent on binding of the viral Tat protein to the transactivation RNA response element. A number of synthetic Tat-transactivation responsive element interaction inhibitors of peptide/peptoid nature were described as potential antiviral drug prototypes. We present a new class of peptidomimetic inhibitors, conjugates of L-arginine with aminoglycosides. Using a gel-shift assay and affinity chromatography on an L-arginine column we found that these compounds bind specifically to the transactivation responsive element RNA in vitro with Kd values in the range of 20-400 nM, which is comparable to the Kd of native Tat bound to the transactivation responsive element (10-12 nM). Confocal microscopy studies demonstrated that fluorescein-labelled conjugate penetrates into live cells. High affinity to the transactivation responsive element, low toxicity, and relative simplicity of synthesis make these compounds attractive candidates for antiviral drug design.
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Affiliation(s)
- A Litovchick
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot, Israel
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