Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The CCR5 beta-chemokine receptor is the coreceptor for macrophage-tropic (M-tropic) strains of HIV-1 and appears to be the principal coreceptor during early stages of human immunodeficiency virus-1 (HIV-1) infection. Approximately 1%-2% of the Western European Caucasian population is homozygous for a 32-bp deletion in the coding region of the CCR5 gene, rendering them less susceptible to HIV infection. These individuals still harbor a normal immune response, thereby making CCR5 an attractive cellular target for anti-HIV therapies. Based on the natural population studies, reduction in CCR5 expression should not affect the physiologic function of the modified cells but should interfere with their susceptibility to HIV-1 infection. To downregulate this receptor, we have designed a hammerhead ribozyme (RZ) that specifically targets the CCR5 mRNA and lacks complementarity to other members of the chemokine receptor gene family. For expression of this highly specific ribozyme, we have taken advantage of the stable transcripts afforded by transcription from the RNA polymerase III (pol III)-based adenoviral VA1 gene. Importantly, the VA1-chimeric ribozyme is stably expressed with a half-life of almost 6 hours. Using this expression system, we show up to 70% downregulation of the elevated levels of CCR5 receptor in the HOS-CD4.CCR5 cell line. The monocytic cell line PM1 was stably transduced with the chimeric VA1 ribozyme constructs. In these cells, substantial resistance to challenge with an M-tropic but not a T-tropic HIV viral strain was observed, demonstrating specificity in downregulating the CCR5 coreceptor. The VA1-CCR5 ribozyme chimeras described in this study should prove useful in both studies of CCR5 receptor function and therapeutic intervention of monocytotropic HIV-1 infection. The VA1 vector described in this study is well suited for the stable cytoplasmic expression of other ribozyme constructs as well.
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PMID:Downregulation of the CCR5 beta-chemokine receptor and inhibition of HIV-1 infection by stable VA1-ribozyme chimeric transcripts. 1098 19

There is considerable confusion concerning the mechanism of lymphocyte death during HIV infection. During the course of HIV infection, M-tropic viruses (R5) that use CCR5 chemokine coreceptors frequently evolve to T-tropic viruses (X4) that use CXCR4 receptors. In this study we show that activation of the CD4 or CCR5 receptor by R5 HIVenv causes a caspase 8-dependent death of both uninfected and infected CD4 T cells. In contrast, CXCR4 activation by X4 HIVenv induces a caspase-independent death of both uninfected CD4 and CD8 T cells and infected CD4 cells. These results suggest that activation of the chemokine receptor by HIVenv determines the mechanism of death for both infected and uninfected T lymphocytes.
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PMID:Chemokine-receptor activation by env determines the mechanism of death in HIV-infected and uninfected T lymphocytes. 1116 Jan 37

During the course of HIV-1 infection, free virus, infected cells, and free HIV-1 proteins circulate within the host, exposing the host endothelium to these viral factors. We have previously presented evidence showing that soluble HIV-1 gp120 protein interacts with chemokine receptors on primary human endothelium and (through those interactions) induces apoptosis as well as other intracellular effects. The current study examines the effect of exposure of vascular endothelium to gp120 IIIb expressed on the surface of Jurkat cells and in the context of viral particles. Apoptosis was observed in human umbilical vein endothelial cell (HUVEC) cultures exposed to gp160-transfected Jurkat cells as well as to virion particles with gp120 on their surface. Additional experiments show that this apoptotic effect was caused by gp120 protein acting through chemokine receptors on the HUVEC surface, primarily the CXCR4 receptor. At higher concentrations of gp120, this lymphotrophic variant, which has been shown to interact predominantly with CXCR4, seems to interact with and induce apoptosis through the CCR5 receptor. Finally, this apoptotic effect in HUVEC cultures occurs at low levels of the inducing agent, gp120, on cell membranes or on virion particles. These results demonstrate that HIV-1 gp120 is capable of interacting with and killing vascular endothelial cells in multiple in vivo contexts.
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PMID:Apoptotic effects in primary human umbilical vein endothelial cell cultures caused by exposure to virion-associated and cell membrane-associated HIV-1 gp120. 1146 39

TAK-779 is a CCR5 antagonist under investigation by Takeda and Kagoshima University for the potential treatment of HIV [324663], [342114]. TAK-779 inhibits chemokine binding to the CCR5 receptor at nanomolar concentrations. However, it has no effect on the binding of chemokines to the CXCR4 receptor [346835]. A US IND for injectable TAK-779 was filed in june 1999, with Takeda initially planning to commence phase I trials in August 1999. However, the FDA did not clear the IND and recommended that Takeda altered the study protocol to include non-invasive measurement of local toxicities and to evaluate other routes of administration. By September 1999, Takeda had conducted some studies in response to the FDA's recommendations and had made efforts to develop an oral formulation. At this time, the company planned to file a new IND application upon completion of the oral formulation [342114]. In August 1995, Lehman Brothers predicted potential worldwide peak sales of US $300 million in
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PMID:TAK-779 (Takeda). 1157 4

Investigations of the structure-activity relationships of 1,3,4-trisubstituted pyrrolidine human CCR5 receptor antagonists afforded orally bioavailable compounds with the ability to inhibit HIV replication in vitro.
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PMID:1,3,4-Trisubstituted pyrrolidine CCR5 receptor antagonists. Part 2: lead optimization affording selective, orally bioavailable compounds with potent anti-HIV activity. 1159 14

Herein we report the preparation of a combinatorial library of compounds with potent CCR5 binding affinity. The library design was aided by SAR generated in a traditional medicinal chemistry effort. Compounds with novel combinations of subunits were discovered that have high binding affinity for the CCR5 receptor. A potent CCR5 antagonist from the library, compound 11 was found to have moderate anti-HIV-1 activity.
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PMID:Combinatorial synthesis of CCR5 antagonists. 1172 Aug 60

A series of CCR5 antagonists containing bicyclic isoxazolidines was generated through a nitrone mediated cycloaddition with olefins bearing the preferred pharmacophores previously described. Potent antagonists (3 and 16) were generated with enhanced affinity for the CCR5 receptor while maintaining antiviral activity against HIV.
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PMID:CCR5 antagonists: bicyclic isoxazolidines as conformationally constrained N-1-substituted pyrrolidines. 1184 99

HIV-1 enters a host cell after an initial interaction between viral envelope glycoprotein gp120 and cell surface receptor CD4, followed by a second interaction between gp120 and a cell surface chemokine receptor. CD4 residue Phe43 makes a significant contribution to the high-affinity interaction between CD4 and env. We and others have used scorpion toxin scaffolds to display and examine CD4 epitopes used for gp120 recognition. These peptides, which have a beta-turn Phe that acts as a Phe43 surrogate, compete with CD4 for gp120 binding and enhance the binding of gp120 to 17b, an antibody that binds near the co-receptor-binding site. In the current study, a scyllatoxin-scaffolded peptide, identified via phage epitope randomization and lacking a beta-turn Phe (indeed, containing no aromatic residues), was shown to behave in a distinctly CD4-like manner. This peptide, denoted [20EGLV23]ST, not only competed with CD4 for gp120 binding, but also enhanced the binding of gp120 to 17b. Quantitatively, an [20EGLV23]ST-gp120 complex exhibited the same 17b binding on-rate as a complex of gp120 with [20AGSF23]ST, a scyllatoxin-based CD4 mimetic peptide containing a beta-turn Phe. In view of this result, we examined the role of Phe43 in CD4 itself by comparing F43V D1D2 sCD4 versus D1D2 sCD4. Like the peptides, a close similarity was observed for both Phe43 and Phe43-less D1D2 sCD4s in enhancing gp120 binding to 17b. Further, when examined for their ability to enhance binding of gp120 to CCR5+ cells, [20EGLV23]ST and [20AGSF23]ST were found to have the same efficacy, after correcting for the difference in their gp120 affinities. These results show that, although Phe43 is important in maintaining high affinity in gp120 ligands, the aromatic residue is not necessary for triggering the conformational isomerization in gp120 that results in formation or exposure of the binding sites for the 17b antibody and the CCR5 receptor.
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PMID:Beta-turn Phe in HIV-1 Env binding site of CD4 and CD4 mimetic miniprotein enhances Env binding affinity but is not required for activation of co-receptor/17b site. 1203 37

Schering-Plough is developing Sch-351125 (Sch-C), the lead in a series of CCR5 inhibitors, for the potential treatment of HIV infection. By March 2001, it had entered phase I studies in the US, however, by April 2001, these had been suspended based in part on observed QTc prolongation at the highest dose. By December 2001, a new phase I trial had been initiated in France. The company has continued to investigate a number of second-generation CCR5 receptor antagonists, including Sch-350634, for the potential treatment of HIV infection. Although it was reported at two separate meetings in early 2001 that Sch-350634 was in phase I/II trials, in April 2001, Schering-Plough confirmed that the compound was not in clinical development at that time and that a preclinical toxicology program was scheduled for late 2001. In December 2001, Morgan Stanley predicted a 2004 launch for a compound arising from the CCR5 inhibitor program, with sales of US$100 million in 2004, US$200 million in 2005, rising to US$300 million in 2006.
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PMID:Sch-351125 and Sch-350634. Schering-Plough. 1205 83

We compared the density of the CCR5 receptor on the surface of CD4+ lymphocytes and monocytes/macrophages of the homozygote (CCR5-59653C) and the heterozygote (CCR5-59653T), bearing CCR2-64V alleles. Flow cytometric analysis revealed lower density of the CCR5 receptor on the surface of CD4+ lymphocytes and monocytes/macrophages of the heterozygote than in the same cells of the homozygote. Our observation might explain slower replication of HIV and the delay in progression to AIDS in the individuals bearing CCR5-59653T transition.
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PMID:Decreased density of the CCR5 receptor on the surface of CD4+ lymphocytes and monocytes/macrophages is associated with the CCR5-59653T transition in the promoter region. 1205 98


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