Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumor necrosis factor (TNF)-alpha has been shown to be increased in brain tissue of AIDS patients and may function as a mediator of cerebral damage. We initiated a study to determine the cellular localization and degree of protein and mRNA expression of the two specific TNF-alpha receptors (TNF-Rs), p55 and p75, in brain tissues from AIDS patients. Cerebral white matter obtained at autopsy from 13 AIDS patients, 10 unhealthy controls, and 4 healthy controls was evaluated. Double-label immunohistochemistry revealed prominent up-regulation of p55 and p75 TNF-Rs on activated macrophages and microglial cells in all AIDS patients; no increased staining was found on astrocytes. Staining was most prominent in patients with opportunistic infection of the brain and in microglial nodules of patients with HIV encephalitis. Brain tissues also showed increased expression of interleukin (IL)-1 beta, IL-6, and TNF-alpha, cytokines known to up-regulate the TNF-Rs. Increased staining for TNF-Rs was also found in patients with multiple sclerosis, chronic cerebral edema, and radiation necrosis but not in an asymptomatic HIV-positive patient without AIDS. Reverse transcriptase polymerase chain reaction performed on adjacent sections from five AIDS patients revealed up-regulation from normal for p55 in all patients and for p75 in three patients. The up-regulation of both TNF-Rs in AIDS suggests that macrophages and microglial cells may be important in amplifying the TNF-alpha response.
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PMID:Increased expression of tumor necrosis factor-alpha receptors in the brains of patients with AIDS. 854 30

Mycobacterium avium complex (MAC) infection is the most common disseminated opportunistic infection encountered in patients with AIDS. We have studied the ability of specific Mycobacterium avium (MA) antigen to stimulate human monocyte-derived macrophages (MDM) to produce tumor necrosis factor-alpha (TNF-alpha). MDM stimulated with MA sonicate, MA 68 kDa and MA 48-52 kDa antigens were found to produce TNF-alpha in a dose-dependent manner. Reverse transcriptase-polymerase chain reaction analysis of mRNA extracts from antigen-stimulated MDM indicated that TNF-alpha mRNA expression was of brief duration and the time point of peak TNF-alpha mRNA levels was found to be antigen-specific. A significant difference in TNF-alpha production in response to MA 48-52 kDa antigen and M. bovis 65 kDa antigen was observed between MDM from normal and HIV positive individuals.
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PMID:Macrophage release of tumor necrosis factor-alpha by Mycobacterium avium antigens. 887 Nov 13

Previous studies have suggested that large quantities of bacterial lipids may accumulate and persist within host cells during chronic stages of Mycobacterium avium infections. This study intended to assess the ability of purified M. avium lipids to affect TH-1-type responses in human peripheral blood mononuclear cells (PBMC) from healthy donors. PBMC were exposed to total lipids and serovar-specific glycopeptidolipids (GPL) extracted from M. avium serovars 4 and 8, which have been reported to predominate as opportunistic infection among AIDS patients. After 24 h exposure to lipids followed by PHA/PMA treatment, IL-2 and IFN-gamma were assayed in the supernatants. Reverse transcriptase polymerase chain reaction (RT-PCR) was used for a semiquantitative estimation of mRNA for IL-2 and IFN-gamma in cell pellets at various time points. Exposure of PBMC to M. avium total lipids significantly suppressed PHA/PMA-induced secretion of IL-2 and IFN-gamma as determined by ELISA. The GPL antigens from serovar 4 were more efficient at inhibiting TH-1 responses than GPL from serovar 8. CD4(+)T-lymphocyte enrichment of PBMC demonstrated that suppression by M. avium lipids was intact without the presence of other cell populations such as monocytes and B-cells. Preliminary RT-PCR experiments showed that the secretion of TH-1 cytokines was partially affected at the transcriptional level. The results obtained showed that M. avium lipids are indeed able to modify the induction of TH-1-type cytokines by human PBMC, and suggest that accumulation of M. avium lipids in the chronic stages of infection may play an important role in the pathogenesis of HIV infection.
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PMID:Exposure of human peripheral blood mononuclear cells to total lipids and serovar-specific glycopeptidolipids from Mycobacterium avium serovars 4 and 8 results in inhibition of TH1-type responses. 1087 86

The human immunodeficiency virus type 1 (HIV-1) Tat protein is essential for viral replication and stimulates transcription of the integrated provirus by recruiting the kinase complex TAK/P-TEFb, composed of cyclin T1 (CycT1) and Cdk9, to the viral TAR RNA element. TAK/P-TEFb phosphorylates the RNA polymerase II complex and stimulates transcriptional elongation. In this report, we investigated the regulation of TAK/P-TEFb in primary human macrophages, a major target cell of HIV infection. While Cdk9 levels remained constant, CycT1 protein expression in freshly isolated monocytes was very low, increased early during macrophage differentiation, and, unexpectedly, decreased to very low levels after about 1 week in culture. The kinase activity of TAK/P-TEFb paralleled the changes in CycT1 protein expression. RNA analysis indicated that the transient induction of CycT1 protein expression involves a posttranscriptional mechanism. In transient transfection assays, the ability of Tat to transactivate the HIV long terminal repeat (LTR) in the late differentiated macrophages was greatly diminished relative to its ability to transactivate the HIV LTR in early differentiated cells, strongly suggesting that CycT1 is limiting for Tat function in late differentiated macrophages. Interestingly, lipopolysaccharide, a component of the cell wall of gram-negative bacteria, reinduced CycT1 expression late in macrophage differentiation. These results raise the possibility that regulation of CycT1 expression may be involved in establishing latent infection in macrophages and that opportunistic infection may reactivate the virus by inducing CycT1 expression.
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PMID:Transient induction of cyclin T1 during human macrophage differentiation regulates human immunodeficiency virus type 1 Tat transactivation function. 1236

Access to antiretroviral therapy is rapidly expanding in resource-limited settings, where tuberculosis is the most common opportunistic infection. Coadministration of antitubercular and antiretroviral agents is, therefore, occurring commonly, and it is associated with 3 major complications. First, induction of cytochrome P-450 enzymes and P-glycoprotein by rifampin results in reduced concentrations of nonnucleoside reverse-transcriptase inhibitors and, particularly, protease inhibitors. This potentially results in the loss of antiviral efficacy and the development of viral resistance. Replacing rifampin with rifabutin, which does not significantly affect the concentrations of antiretroviral agents, is advocated but is currently unaffordable in resource-limited settings. Second, overlapping toxicities of antitubercular and antiretroviral agents occur frequently, necessitating discontinuation of therapy and increasing the risk of nonadherence. Third, immunopathological reactions, termed "the immune reconstitution inflammatory syndrome," occur frequently when antiretroviral therapy is initiated in patients with tuberculosis. These complexities of coadministration of antitubercular and antiretroviral agents are reviewed, and research priorities are highlighted.
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PMID:Complications of antiretroviral therapy in patients with tuberculosis: drug interactions, toxicity, and immune reconstitution inflammatory syndrome. 1762 28

Raltegravir is a first-in-class HIV-1 integrase inhibitor with established antiviral efficacy in treatment-naive and treatment-experienced patients with multidrug-resistant HIV-1 infection. In this article, we summarize pharmacoeconomic evaluations of raltegravir-based treatment regimens, compared with alternative therapies, in the treatment of patients with HIV infection and/or AIDS. Cost-effectiveness evaluations of raltegravir in treatment-experienced patients conducted using a continuous-time, state-transition Markov cohort model suggest that raltegravir, combined with optimized background therapy, falls within the range that would generally be considered cost effective compared with optimized therapy alone in Spanish, Swiss and UK health systems. In treatment-naive populations, raltegravir was evaluated using a three-stage continuous-time state-transition cohort model. Raltegravir-based initiation treatment strategies (first-line raltegravir) were compared with protease inhibitor and non-nucleoside reverse-transcriptase inhibitor initiation strategies, in which raltegravir was retained for salvage therapy. First-line raltegravir was cost-effective versus retaining raltegravir for salvage therapy in several European populations. A separate economic model was used to evaluate first-line raltegravir against two alternative initiation regimens representing standard clinical practice in Australia; raltegravir proved to be cost effective in both scenarios. In all studies examined, results were sensitive to factors including treatment duration, mortality rate, analytic time horizon, health utility weights, cost of raltegravir and optimized therapy, incidence of opportunistic infection and discount rates. Nonetheless, raltegravir remained cost effective under most scenarios.
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PMID:Cost-effectiveness of raltegravir in HIV/AIDS. 2209 78

The 2017 Conference on Retroviruses and Opportunistic Infections (CROI) featured exciting preclinical data on investigational antiretroviral agents with good in vitro efficacy and long half-lives. Investigational medications, including bictegravir, demonstrated excellent efficacy and tolerability, as did dual-agent therapy with dolutegravir paired with rilpivirine or with lamivudine. Dolutegravir monotherapy proved inadvisable due to virologic failure and resistance. The gap between high- and low-income settings along the HIV care continuum is narrowing, with Zimbabwe, Malawi, and Zambia approaching the 90-90-90 targets established by the joint United Nations Programme on HIV/AIDS (UNAIDS), whereas communities in the Southern United States are falling behind. Innovative strategies to improve outcomes include 2-way text messaging, home-based HIV testing, peer navigation, and New York City's realignment of services into comprehensive sexual health programs. A high prevalence of resistance was documented in low- and middle-income settings and policy considerations were modeled to address increasing resistance rates. Novel resistance mutations to integrase strand transfer inhibitors and nucleoside analogue reserve transcriptase inhibitors were identified, but the clinical implications are unclear and require further investigation. Several studies provided insights on dosing and safety of antiretroviral therapy to prevent mother-to-child transmission through pharmacokinetic analysis. A special session devoted to Zika virus included a study of its effects on the central nervous system and a promising animal study of a Zika vaccine.
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PMID:CROI 2017: Advances in Antiretroviral Therapy. 2859 90

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