Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

CC chemokine receptor 5 (CCR5) is a coreceptor for cellular entry of monocyte-tropic (R5) strains of human immunodeficiency virus (HIV) type 1, which has been implicated as the predominant phenotype of HIV in early infection. The CCR5 agonists macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and RANTES (regulated on activation, normally T cell-expressed and -secreted) have been shown to block replication of R5 virus in vitro and have gained attention as potential antiviral factors. However, a few reports have suggested that other chemokines may also block R5 HIV-1, including monocyte chemoattractant protein (MCP)-2 (CC chemokine ligand 8). We demonstrate that MCP-2 specifically inhibits replication of R5 HIV-1 and that this activity is additive to that of RANTES. Furthermore, MCP-2 induces a robust, pertussis toxin-sensitive calcium flux in primary lymphocytes, and cross-desensitization studies indicate that MCP-2 acts via CCR5. These data confirm that MCP-2 is a ligand for CCR5 on CD4(+) lymphocytes and can specifically block R5 HIV-1.
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PMID:Monocyte chemoattractant protein-2 (CC chemokine ligand 8) inhibits replication of human immunodeficiency virus type 1 via CC chemokine receptor 5. 1193 Mar 29

Chemokines and chemokine receptors play a crucial role in the trafficking of leukocyte populations across the body, and are involved in the development of a large variety of human diseases. CCR5 is the main coreceptor used by macrophage (M)-tropic strains of human immunodeficiency virus type 1 (HIV-1) and HIV-2, which are responsible for viral transmission. CCR5 therefore plays an essential role in HIV pathogenesis. A number of inflammatory CC-chemokines, including MIP-1 alpha, MIP-1 beta, RANTES, MCP-2, and HCC-1[9-74] act as CCR5 agonists, while MCP-3 is a natural antagonist of the receptor. CCR5 is mainly expressed in memory T-cells, macrophages, and immature dendritic cells, and is upregulated by proinflammatory cytokines. It is coupled to the Gi class of heterotrimeric G-proteins, and inhibits cAMP production, stimulates Ca2+ release, and activates PI3-kinase and MAP kinases, as well as other tyrosine kinase cascades. A mutant allele of CCR5, CCR5 delta 32 is frequent in populations of European origin, and encodes a nonfunctional truncated protein that is not transported to the cell surface. Homozygotes for the delta 32 allele exhibit a strong, although incomplete, resistance to HIV infection, whereas heterozygotes display delayed progression to acquired immunodeficiency syndrome (AIDS). Many other alleles, affecting the primary structure of CCR5 or its promoter have been described, some of which lead to nonfunctional receptors or otherwise influence AIDS progression. CCR5 is considered as a drug target in the field of HIV, but also in a growing number of inflammatory diseases. Modified chemokines, monoclonal antibodies and small chemical antagonists, as well as a number of gene therapy approaches have been developed in this frame.
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PMID:CCR5 and HIV infection. 1240 6

Immature dendritic cells are among the first cells infected by retroviruses after mucosal exposure. We explored the effects of human immunodeficiency virus-1 (HIV-1) and its Tat transactivator on these primary antigen-presenting cells using DNA microarray analysis and functional assays. We found that HIV-1 infection or Tat expression induces interferon (IFN)-responsive gene expression in immature human dendritic cells without inducing maturation. Among the induced gene products are chemokines that recruit activated T cells and macrophages, the ultimate target cells for the virus. Dendritic cells in the lymph nodes of macaques infected with simian immunodeficiency virus (SIV) have elevated levels of monocyte chemoattractant protein 2 (MCP-2), demonstrating that chemokine induction also occurs during retroviral infection in vivo. These results show that HIV-1 Tat reprograms host dendritic cell gene expression to facilitate expansion of HIV-1 infection.
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PMID:HIV-1 Tat reprograms immature dendritic cells to express chemoattractants for activated T cells and macrophages. 1256 32

CCR5 is a G protein-coupled receptor for RANTES, MIP-1alpha, MIP-1beta, and MCP-2 that functions as the front line coreceptor for human immunodeficiency virus type 1 infection. To elucidate the mechanism for CCR5 activation, this coreceptor was expressed in yeast coupled to the pheromone response pathway and a constitutively active mutant (CAM) was derived by random mutagenesis. Conversion of Thr-82 in the highly conserved TXP motif in transmembrane helix 2 to Pro, His, Tyr, Arg, or Lys conferred autonomous signaling activity in yeast and mammalian cells. This substitution also imparted constitutive signaling to CCR2 in yeast and mammalian cells, but not CCR1, CCR3, CCR4, CXCR2, or CXCR4. The CCR5-CAM, but not the CCR2-CAM had a reduction in ligand binding affinity. Whereas the amplitude of calcium mobilization induced by RANTES stimulation was lower in the CCR5-CAM than the wild-type (WT) receptor, MCP-1 induced a higher signal in the CCR2-CAM than in CCR2-WT. The chemotactic response of CCR5-CAM(T82P) to RANTES was similar to that of CCR5-WT, but CCR5-CAM(T82K) was dramatically decreased. The chemotactic response of CCR2-WT and CCR2-CAM(T94K) were similar. These findings extend insight into the role of the TXP motif in the mechanism for CCR5 signaling. CCR2, the receptor most closely genetically related to CCR5, shared a similar signaling mechanism, but other receptors containing the TXP motif did not. The expression of CCR5 and CCR2 in yeast and the availability of variants with autonomous signaling represent critical tools for characterizing receptor antagonists and developing approaches to block their role in human diseases.
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PMID:Constitutive activation of CCR5 and CCR2 induced by conformational changes in the conserved TXP motif in transmembrane helix 2. 1283 56

Acyclic nucleoside phosphonates are potent antiviral agents effective against replication of DNA viruses and retroviruses including human immunodeficiency virus (HIV). In addition to their antimetabolic mode of antiviral action, acyclic nucleoside phosphonates also possess immunomodulatory properties. We have shown recently that a number of them stimulate secretion of cytokines including chemokines RANTES/CCL5 ("regulated upon activation, normal T cell expressed and secreted") and MIP-1 alpha/CCL3 (macrophage inflammatory protein-1 alpha) that may inhibit entry of HIV in cells. In present experiments we analyzed effects of acyclic nucleoside phosphonates on gene expression of other members of the beta family of chemokines, monocyte chemotactic proteins (MCPs), which have also been implicated in the control of HIV infection. The following compounds differing at the type of heterocyclic base, i.e. adenine (A), or 2,6-diaminopurine (DAP), at the 6-amino group of the base, and at the N ( 9 )-side chain represented by 9-[2-(phosphonomethoxy)ethyl] (PME) and 9-[2-(phosphonomethoxy)propyl] (PMP) moieties were included in the study: (1) (R)-PMPA, ie. tenofovir, (2) N ( 6 )-cyclopropyl-(R)-PMPDAP, (3) N ( 6 )-cyclopentyl-(R)-PMPDAP, (4) N ( 6 )-dimethylaminoethyl-(R)-PMPDAP, (5) N ( 6 )-cyclopentyl-PMEDAP, (6) N ( 6 )-isobutyl-PMEDAP, (7) N ( 6 ) -cyclohexylmetyl-PMEDAP, and (8) N ( 6 ) -cyclooctyl-PMEDAP. These compounds are able to activate production of MCP-1 and MCP-3, and none of them influences gene expression of MCP-2, and MCP-5. Enhancement of monocyte chemotactic protein expression was found to be mediated by transcriptional factor nuclear factor-kappaB (NF-kappaB).
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PMID:Acyclic nucleoside phosphonate antivirals activate gene expression of monocyte chemotactic protein 1 and 3. 1703 77

Primary human neuron cultures are an important in vitro model system for studies on mechanisms involved in human immunodeficiency virus (HIV)-associated dementia (HAD) and other neurological disorders. Here, more than 80 cell surface antigens were screened to identify a marker that could readily distinguish between neurons and astrocytes and found that neurons lack CD44 surface expression, whereas astrocytes and other cell types in brain are CD44+. Neurons and astrocytes were isolated from human fetal brain based on differential expression of CD44. Using purified neurons cocultured with astrocytes and/or microglia, it was demonstrated that HIV infection of microglia induces cellular activation and production of soluble factors that activate uninfected microglia and astrocytes and induce neuronal cell death. Activated astrocytes promoted HIV replication in microglia, thereby amplifying HIV-induced neurotoxicity. A screen for 120 cytokine/proteins detected upregulation of insulin-like growth factor (IGF)-binding protein (IGFBP)-2, interleukin (IL)-6, and CCL8/MCP-2 (monocyte chemoattractant protein 2) in supernatants of HIV-infected brain cell cultures. IGF-1 and -2 increased neuronal survival in HIV-infected brain cell cultures, whereas IGFBP-2 inhibited prosurvival effects of these growth factors. These findings identify CD44 as a marker that can be used to sort neurons from other cell types in brain, suggest the importance of microglia-astrocyte interactions in neurodegenerative mechanisms associated with HIV infection, and indicate a role for insulin-like growth factors in neuroprotection from HIV-induced neurodegeneration. The ability to reconstitute brain cultures using isolated populations of neurons, astrocytes, and microglia will be valuable for studies on pathogenic mechanisms in HAD and other neurological disorders, and will also facilitate neuroactive drug discovery.
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PMID:Reconstitution of human immunodeficiency virus-induced neurodegeneration using isolated populations of human neurons, astrocytes, and microglia and neuroprotection mediated by insulin-like growth factors. 1716 63

Chemokines regulate leukocyte migration during physiological and pathological conditions. They exert their biological activity through interaction with 7-transmembrane spanning G protein-coupled receptors (GPCR) and are presented on glycosaminoglycans (GAG) linked to endothelial cell layers. Specific chemokines and chemokine receptors affect angiogenesis or are targets for viral mimicry, e.g. by human immunodeficiency virus (HIV). Several enzymes, in particular proteases, have been described to process chemokines at specific sites generating chemokine isoforms that were also identified from natural sources. For some chemokines, e.g. CXCL8 and CCL3L1, posttranslational modification results in enhanced biological activity. For CXCL7 and CCL14 truncation is even mandatory for receptor signaling and chemotactic properties. The activity of many other chemokines is down-regulated by processing and receptor antagonists are generated, e.g. for truncated CCL8 and CCL11. Moreover, some processed chemokines such as CCL5(3-68) show enhanced affinity for one receptor (CCR5) and reduced interaction with other receptors (CCR1 and CCR3) resulting in differential changes in leukocyte response. These posttranslational mechanisms, in addition to gene duplication, transcriptional and translational regulation of chemokine ligand and receptor expression, GAG binding properties, expression of "silent" receptors and synergistic interaction between chemokines, modulate chemokine activity in a complex manner. This report reviews current understanding on the regulation of the chemokine network through posttranslational modification and its consequences for leukocyte migration, angiogenesis and protection against viral infection.
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PMID:Regulation of chemokine activity by posttranslational modification. 1879 69

Human immunodeficiency virus (HIV)-associated dementia (HAD) is a syndrome occurring in HIV-infected patients with advanced disease that likely develops as a result of macrophage and microglial activation as well as other immune events triggered by virus in the central nervous system. The most relevant experimental model of HAD, rhesus macaques exhibiting simian immunodeficiency virus (SIV) encephalitis (SIVE), closely reproduces the human disease and has been successfully used to advance our understanding of mechanisms underlying HAD. In this study we integrate gene expression data from uninfected and SIV-infected hippocampus with a human protein interaction network and discover modules of genes whose expression patterns distinguish these two states, to facilitate identification of neuronal genes that may contribute to SIVE/HIV cognitive deficits. Using this approach we identify several downregulated candidate genes and select one, EGR1, a key molecule in hippocampus-related learning and memory, for further study. We show that EGR1 is downregulated in SIV-infected hippocampus and that it can be downregulated in differentiated human neuroblastoma cells by treatment with CCL8, a product of activated microglia. Integration of expression data with protein interaction data to discover discriminatory modules of interacting proteins can be usefully used to prioritize differentially expressed genes for further study. Investigation of EGR1, selected in this manner, indicates that its downregulation in SIVE may occur as a consequence of the host response to infection, leading to deficits in cognition.
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PMID:An integrated systems analysis implicates EGR1 downregulation in simian immunodeficiency virus encephalitis-induced neural dysfunction. 1981 22


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