UMLS:C0019693 - FACTA Search

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Query: UMLS:C0019693 (HIV)
170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chemokines are important mediators of inflammation. It has been demonstrated that there is an increase in chemokine expression in both the sera and brain of individuals infected with human immunodeficiency virus type 1 (HIV-1). The HIV-1 viral protein, Tat, a transcriptional regulator, has been detected in the central nervous system (CNS) of infected individuals, and has been demonstrated to induce chemokines from various cells within the brain. The authors now show that the interaction of human microglia, the resident phagocytes of the brain, with Tat leads to dramatic increases in the secretion of the chemokines CCL2, CXCL8, CXCL10, CCL3, CCL4, and CCL5. Treatment of microglia with Tat plus specific inhibitors of signal transduction pathways demonstrated that the induction of each chemokine is regulated differently. Tat-induced expression of CCL2 and CCL4 was mediated by the activation of the extracellular regulated kinase (ERK)1/2 mitogen-activated protein kinase (MAPK) pathway and the phosphatidylinositol 3-kinase (PI3K) pathway, whereas the induction of CXCL8 and CCL3 was mediated only by the p38 MAPK pathway. Tat-induced CXCL10 expression was mediated, to some extent, by activation of the ERK1/2 MAPK pathway, phosphatidylinositol 3-kinase pathway, and the p38 MAPK pathway, whereas CCL5 expression was not mediated by any pathway tested. Western blot analysis demonstrated phosphorylation of ERK 1/2 and Akt upon stimulation of microglia with Tat. These data suggest that a soluble HIV-1 viral protein can alter the chemokine balance in the brain, which can then lead to an influx of inflammatory cells and contribute to the neuropathogenesis of HIV-1 infection.
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PMID:Expression of chemokines by human fetal microglia after treatment with the human immunodeficiency virus type 1 protein Tat. 1520 27

CD8 T cells play a key role in host defense against intracellular pathogens. Efficient migration of these cells into sites of infection is therefore intimately linked to their effector function. The molecular mechanisms that control CD8 T-cell trafficking into sites of infection and inflammation are not well understood, but the chemokine/chemokine receptor system is thought to orchestrate this process. Here we systematically examined the chemokine receptor profile expressed on human CD8 T cells. Surprisingly, we found that CXC chemokine receptor 1 (CXCR1), the predominant neutrophil chemokine receptor, defined a novel interleukin-8/CXC ligand 8 (IL-8/CXCL8)-responsive CD8 T-cell subset that was enriched in perforin, granzyme B, and interferon-gamma (IFNgamma), and had high cytotoxic potential. CXCR1 expression was down-regulated by antigen stimulation both in vitro and in vivo, suggesting antigen-dependent shaping of the migratory characteristics of CD8 T cells. On virus-specific CD8 T cells from persons with a history of Epstein-Barr virus (EBV) and influenza infection, CXCR1 expression was restricted to terminally differentiated effector memory cells. In HIV-1 infection, CXCR1-expressing HIV-1-specific CD8 T cells were present only in persons who were able to control HIV-1 replication during structured treatment interruptions. Thus, CXCR1 identifies a subset of CD8 T cells poised for immediate cytotoxicity and early recruitment into sites of innate immune system activation.
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PMID:IL-8 responsiveness defines a subset of CD8 T cells poised to kill. 1529 66

Regulation of cytokine and chemokine expression in microglia may have implications for CNS inflammatory disorders. In this study we examined the role of the cyclopentenone PG 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)) in microglial inflammatory activation in primary cultures of human fetal microglia. 15d-PGJ(2) potently inhibited the expression of microglial cytokines (IL-1, TNF-alpha, and IL-6). We found that 15d-PGJ(2) had differential effects on the expression of two alpha-chemokines; whereas the Glu-Lys-Arg (ELR)(-) chemokine IFN-inducible protein-10/CXCL10 was inhibited, the ELR(+) chemokine IL-8/CXCL8 was not inhibited. These findings were shown in primary human microglia and the human monocytic cells line THP-1 cells, using diverse cell stimuli such as bacterial endotoxin, proinflammatory cytokines (IL-1 and TNF-alpha), IFN-beta, and HIV-1. Furthermore, IL-8/CXCL8 expression was induced by 15d-PGJ(2) alone or in combination with TNF-alpha or HIV-1. Combined results from EMSA, Western blot analysis, and immunocytochemistry showed that 15d-PGJ(2) inhibited NF-kappaB, Stat1, and p38 MAPK activation in microglia. Adenoviral transduction of super-repressor IkappaBalpha, dominant negative MKK6, and dominant negative Ras demonstrated that NF-kappaB and p38 MAPK were involved in LPS-induced IFN-inducible protein 10/CXCL10 production. Interestingly, although LPS-induced IL-8/CXCL8 was dependent on NF-kappaB, the baseline or 15d-PGJ(2)-mediated IL-8/CXCL8 production was NF-kappaB independent. Our results demonstrate that 15d-PGJ(2) has opposing effects on the expression of two alpha-chemokines. These data may have implications for CNS inflammatory diseases.
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PMID:15-deoxy-Delta12,14-prostaglandin J2 inhibits IFN-inducible protein 10/CXC chemokine ligand 10 expression in human microglia: mechanisms and implications. 1532 15

Toll-like receptor 2 (TLR2) stimulation in monocytes may contribute to enhanced inflammation and viral replication in HIV infection. In the present study we examined if TLR2 stimulation could modulate chemokine responses in peripheral blood mononuclear cells (PBMC) from HIV-infected patients and healthy controls. Our main findings were, with similar qualitative patterns in both healthy controls and HIV-infected patients: (1) TLR2 stimulation induced up-regulation of several chemokines at the mRNA level as well as increased protein levels of macrophage inflammatory protein (MIP)-1alpha, interleukin (IL)-8 and regulated on activation, normal T cell expressed and secreted (RANTES); (2) TLR2 stimulation induced enhanced protein expression of CCR5 (a receptor for MIP-1alpha and RANTES) on monocytes; (3) In vitro stimulation with RANTES induced release of MIP-1alpha, MCP-1, IL-8 and interferon-gamma from PBMC. While increased levels of beta-chemokines possibly have antiviral effects, TLR2 stimulation may also promote a chemokine-driven inflammatory loop, potentially contributing to the immunopathogenesis of HIV infection.
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PMID:Stimulation of toll-like receptor 2 in mononuclear cells from HIV-infected patients induces chemokine responses: possible pathogenic consequences. 1537 13

Viral latency is a long-term pathogenic condition in patients infected with HIV-1. Low but sustained virus replication in chronically infected cells can be activated by stimulation with proinflammatory cytokines such as TNF-alpha, IL-1 beta, or other host factors. However, the precise mechanism by which cellular activation induces latently infected cells to produce virions has remained unclear. In the present report, we present evidence that activation of HIV-1 replication in latently infected U1 or ACH2 cells by human macrophages is mediated by a rapid nuclear localization of NF-kappaB p50/p65 dimer with concomitant increased expression of proinflammatory cytokines. Multiplexed RT-PCR amplification of mRNA isolated from cocultures of macrophages and U1 and ACH2 cells showed significant induction of IL-1beta, IL-6, IL-8, TNF-alpha, and TGF-beta expression within 3 h of coincubation. Fixation of macrophages, U-1, or ACH2 cells with paraformaldehyde before coculture completely abrogated the induction of NF-kappaB subunits and HIV-1 replication, suggesting that cooperative interaction between the two cell types is an essential process for cellular activation. Pretreatment of macrophage-U1 or macrophage-ACH2 cocultures with neutralizing anti-TNF-alpha Ab down-regulated the replication of HIV-1. In addition, pretreatment of macrophage-U1 or macrophage-ACH2 cocultures with the NF-kappaB inhibitor (E)3-[(4-methylphenyl)sulfonyl]-2-propenenitrile (BAY 11-7082) prevented the induction of cytokine expression, indicating a pivotal role of NF-kappaB-mediated signaling in the reactivation of HIV-1 in latently infected cells by macrophages. These results provide a mechanism by which macrophages induce HIV-1 replication in latently infected cells.
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PMID:Mechanisms for macrophage-mediated HIV-1 induction. 1555 66

Since macrophage activation can now be studied at a global level using modern microarray and proteomic analyses, discovery of novel macrophage activation genes is inevitable and important for understanding HIV-associated dementia (HAD). We isolated two different types of primary human macrophages: microglia and monocyte-derived macrophages (MDM) from brain tissue and whole blood, respectively. The microarray analysis of differentially regulated macrophage activation genes reported here supports our previous assertions that the mixed glia (MIX) cultured in starvation conditions (DMEM alone) are a non-activated, or "quiescent", tissue culture model for studying macrophage activation in the brain. Transcript levels from these quiescent cultures provided a background level of gene expression and allowed for the identification of upregulated macrophage activation genes in the MIX brain cultures upon treatment with an array of soluble activation factors: serum components, cytokines, and growth factors. We found that 914 genes in the MIX cultures and 734 genes in the MDM cultures had a greater than twofold increase in expression. We discovered 180 genes with expression that was increased more than twofold in both culture types. Microarray-specific statistical analyses were performed to complement fold change analysis: significance analysis of microarrays (SAM) and Partek Pro. In the MIX cultures, we detected over a 100-fold increase in IL-1beta and TIMP1 transcription; Caspase 9, S100A8 and 9, MMP12, IL-8, monocyte chemotactic protein 1 (MCP1), MRC-1, and IL-6 were also upregulated. Activation of starved MDM cultures resulted in fewer upregulated genes compared to MIX cultures. Genes upregulated in both MIX and MDM included CCL2 (MCP1), CCL7, CXCL5, TNFSF14, kinases, and phosphatases. These microarray data may provide leads for identifying previously unknown neurotoxins, disease biomarkers, and pathways responsible for the neuronal apoptosis observed in HAD and for the eventual identification of therapeutic targets and treatments.
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PMID:Microarray analysis of activated mixed glial (microglia) and monocyte-derived macrophage gene expression. 1557 77

In animal models, immunity to cryptococcal infection, as in many chronic fungal and bacterial infections, is associated with a granulomatous inflammatory response, intact cell-mediated immunity, and a Th1 pattern of cytokine release. To examine the correlates of human immunity to cryptococcal infection in vivo, we analyzed immune parameters at the site of infection over time and assessed the rate of clearance of infection by serial quantitative cerebrospinal fluid (CSF) fungal cultures in 62 patients in a trial of antifungal therapy for HIV-associated cryptococcal meningitis. CSF IL-6, IFN-gamma, TNF-alpha, and IL-8 were significantly higher in survivors compared with nonsurvivors. There were negative correlations between log TNF-alpha, IFN-gamma, and IL-6 levels and baseline cryptococcal CFU. Log IFN-gamma, G-CSF, TNF-alpha, and IL-6 were correlated positively with the rate of fall in log CFU/ml CSF/day. In a linear regression model including antifungal treatment group, baseline CFU, and these cytokines, only treatment group and log IFN-gamma remained independently associated with rate of clearance of infection. The results provide direct in vivo evidence for the importance of quantitative differences in IFN-gamma secretion in human immune control of granulomatous infections, and increase the rationale for adjunctive IFN-gamma in the treatment of refractory HIV-associated cryptococcosis.
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PMID:IFN-gamma at the site of infection determines rate of clearance of infection in cryptococcal meningitis. 1566 40

Contraceptive microbicides formulated as vaginal gels offer the possibility of women-controlled contraception and prevention of HIV infection. However, the effects of these gels on the upper reproductive tract is largely unknown. The purpose of this study was to determine the effects of nonoxynol-9 (N-9) on human endometrium. Human endometrial biopsies were cultured and incubated with various dosages of N-9 for 6 or 24 h. Endometrial histology was assessed by light microscopy using hematoxylin and eosin. Inflammatory response was determined by analyzing proinflammatory cytokines with enzyme-linked immunosorbent assay. Endometrial mucin was assessed by immunohistochemistry and real-time polymerase chain reaction. Histological changes consistent with focal coagulative necrosis were seen after 6 and 24 h of culture. All cytokines (interleukin 1beta, tumor necrosis factor alpha and interleukin 8) decreased at all concentrations of N-9 after 24 h of incubation. The expression of Mucin1 (MUC-1) was inhibited in a dose-dependent manner at both the protein and messenger RNA levels. These results demonstrate for the first time that N-9 has multiple, potential deleterious effects on the human endometrium characterized by necrosis, alteration of proinflammatory cytokines and inhibition of MUC-1 expression. Taken together, these in vitro findings suggest that N-9 can interrupt the functional barrier provided by the endometrium and, thus, facilitate infection with HIV and other pathogens.
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PMID:The effect of nonoxynol-9 on human endometrium. 1570 64

The aim of this study was to characterize the immune system profile in the uterine cervix of 17 human papillomavirus (HPV)-infected women, compared with 17 whom were coinfected with HIV-1. Five histologically normal cervices in immunocompetent women were used as controls. HPV infection was associated with a marked increase in cells expressing interleukin (IL)-6, interferon gamma (IFN-gamma), and tumor necrosis factor alpha (TNF-alpha). Coinfection by HPV and HIV-1 led to decreased expression of IL-6, TNF-alpha, and IFN-gamma. However, coinfection led to increased numbers of cells expressing IL-4, IL-10, and IL-8. Compared with the histologically normal cervices, increased numbers of macrophages (CD68, RFD7) and T lymphocytes (CD4, CD8) were seen in HPV-infected cervices; coinfection with HIV-1 was associated with a higher number of CD8 cells and lower number of CD68 cells. HPV DNA localized exclusively to the dysplastic squamous cells, whereas HIV-1 RNA was detected mainly in CD68-positive stromal cells. In conclusion, this study shows differential expression of various cytokines and classes of inflammatory cells, relative to HIV-1 infection and HPV coinfection, which may relate to the risk of transmission of HIV-1 and increased risk of cervical cancer in these women.
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PMID:Distribution of immune cell subsets and cytokine-producing cells in the uterine cervix of human papillomavirus (HPV)-infected women: influence of HIV-1 coinfection. 1571 63

Interleukin-8 (IL-8) is the predominant cytokine expressed in the female genital tract of women with certain infectious/inflammatory conditions. IL-8 increased HIV-1 replication in T cells and to a greater extent in monocytes/macrophages in vitro. Physiological levels of IL-8 increased susceptibility to HIV-1 infection 5- to 8-fold in cervical explant tissues. Competitive inhibition of the IL-8 receptor CXCR2 with the small molecule inhibitor SB225002 resulted in a 45-70% decrease in cervical explant susceptibility to HIV-1 infection.
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PMID:IL-8 increases transmission of HIV type 1 in cervical explant tissue. 1579 29

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