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:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human T-cell leukemia virus type 1 (HTLV-1) infection is associated with adult T-cell leukemia and HTLV-associated myelopathy/tropical spastic paraparesis. Inhibition of HTLV-1 transmission is important to prevent the above HTLV-1-associated diseases. We used the antisense oligodeoxynucleotides (oligos) complementary to the first splice junction, rex responsive site, gag, env, tax, rex, and p21 and evaluated the effects on the syncytium formation between HTLV-1 producing human T-cell line, C9/PL cells, and HTLV-1-uninfected human glioma cell line, U251-MG cells. The syncytium formation was significantly inhibited the virion production assayed by antisense oligos to env, tax, gag, p21, and rex, with antisense oligo to env being the most inhibitory. Antisense oligos to env and tax also inhibited reverse transcriptase activity. Antisense oligo to env may have a potential as a preventive measure of HTLV-1 replication and transmission in vivo.
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PMID:Inhibition of human T-cell leukemia virus type 1 replication by antisense env oligodeoxynucleotide. 947 88

Patients with human T-cell leukemia virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) typically have a high HTLV-1 proviral load in peripheral blood mononuclear cells and abundant, activated HTLV-1-specific cytotoxic T lymphocytes (CTLs). No effective treatment for HAM/TSP has been described so far. We report a 10-fold reduction in viral DNA for five patients with HAM/TSP during treatment with the reverse transcriptase inhibitor lamivudine. In one patient with recent-onset HAM/TSP, the reduction in viral DNA was associated with a fall in the frequency of CTLs specific to two peptides in the immunodominant viral antigen Tax. The half-life of peripheral blood mononuclear cell populations was estimated from changes in viral DNA copy number, CTL frequency, reduction in CD25 expression, and the loss of dicentric chromosomes following radiation-induced damage. Each of these four different techniques indicated a cellular half-life of approximately 3 days consistent with continuous lymphocyte replication and destruction. These results indicate that viral replication through reverse transcription significantly contributes to the maintenance of HTLV-1 viral DNA load. The relative contribution of proliferation versus replication may vary between infected people.
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PMID:Effect of lamivudine on human T-cell leukemia virus type 1 (HTLV-1) DNA copy number, T-cell phenotype, and anti-tax cytotoxic T-cell frequency in patients with HTLV-1-associated myelopathy. 1055 46

A wide variety of disorders of diverse pathogenic mechanisms can trigger spinal cord dysfunction in HIV-1-infected patients. The most common such condition is HIV-1-associated myelopathy (HM) which characteristically complicates advanced HIV-1 disease in patients with low CD4 cell counts and previous AIDS-defining diagnoses. We describe an unusual presentation of HM in a previously asymptomatic patient with a relatively preserved CD4 cell count (458 cells/mm3) who was even unaware of his serological status. The patient presented with a clinically severe, slowly progressive myelopathy and could not walk unassisted. Significant neurological improvement could be obtained as rapidly as within 4 weeks after the institution of an antiretroviral combination of only two nucleoside analog HIV-1 reverse transcriptase inhibitors (zidovudine and didanosine). An HIV-1 protease inhibitor was also prescribed at that point but could only be added to intensify the regimen 3 months later, when significant neurological improvement had already been recorded. We also review the disorders reported to derange spinal cord function in previously asymptomatic HIV-1-infected patients.
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PMID:Myelopathy in a previously asymptomatic HIV-1-infected patient. 1133 84

T cells recognizing self or microbial antigens may trigger or reactivate immune-mediated diseases. Monitoring the frequency of specific T cell clonotypes to assess a possible link with the course of disease has been a difficult task with currently available technology. Our goal was to track individual candidate pathogenic T cell clones, selected on the basis of previous extensive studies from patients with immune-mediated disorders of the CNS, including multiple sclerosis, HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) and chronic Lyme neuroborreliosis. We developed and applied a highly specific and sensitive technique to track single CD4(+) and CD8(+) T cell clones through the detection and quantification of T cell receptor (TCR) alpha or beta chain complementarity-determining region 3 transcripts by real-time reverse transcriptase (RT)-PCR. We examined the frequency of the candidate pathogenic T cell clones in the peripheral blood and CSF during the course of neurological disease. Using this approach, we detected variations of clonal frequencies that appeared to be related to clinical course, significant enrichment in the CSF, or both. By integrating clonotype tracking with direct visualization of antigen-specific staining, we showed that a single T cell clone contributed substantially to the overall recognition of the viral peptide/MHC complex in a patient with HAM/TSP. T cell clonotype tracking is a powerful new technology enabling further elucidation of the dynamics of expansion of autoreactive or pathogen-specific T cells that mediate pathological or protective immune responses in neurological disorders.
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PMID:Molecular tracking of antigen-specific T cell clones in neurological immune-mediated disorders. 1247 92

The number of clinical manifestations associated with human T-cell lymphotrophic virus type 1 infection continues to expand, as does the number of regulatory genes that human T-cell lymphotrophic virus 1 either transactivates or binds to directly. The relationship with the immunogenetics of the host is becoming more crucial with specific human leukocyte antigen types determining the risk of developing tropical spastic paraparesis/human T-cell lymphotrophic virus 1 associated myelopathy or adult T-cell leukaemia and lymphoma. Perhaps surprisingly, given the complexity of the virus-host interaction and the poor response to treatment of human T-cell lymphotrophic virus 1 associated conditions so far, a really remarkable response to azathioprine and alpha-interferon is reported for patients with adult T-cell leukaemia. Other reverse transcriptase inhibitors may also be effective in adult T-cell leukaemia and lymphoma and tropical spastic paraparesis/human T-cell lymphotrophic virus 1 associated myelopathy, although the fact that adult T-cell leukaemia is a monoclonal expansion disease that no longer requires virus replication per se, raises the question as to whether or not azathioprine is acting as an anti-cancer agent, which was its original role before the anti-HIV screening programme.
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PMID:Human T-cell lymphotrophic virus type 1: infections and pathogenesis. 1703 89

Human T-cell leukemia virus type-1 (HTLV-1) is associated with a number of human diseases. Although the mechanism by which the virus causes diseases is still not known, studies indicate that viral replication is critical for the development of HTLV-1 associated myelopathy, and initial studies suggested that blocking replication with reverse transcriptase inhibitors had a therapeutic effect. Therefore, based on the success of HIV-1 protease inhibitors, the HTLV-1 protease is also a potential target for chemotherapy. Furthermore, mutated residues in HIV-1 protease that confer drug resistance are frequently seen in equivalent positions of other retroviral proteases, like HTLV-1 protease. Therefore, comparison of HTLV-1 and HIV-1 proteases is expected to aid the rational design of broad spectrum inhibitors effective against various retroviral proteases, including the mutant HIV-1 enzymes appearing in drug resistance. This review describes the characteristics of HTLV-1 protease, makes comparison with HIV-1 protease, and discusses the status of inhibitor development for the HTLV-1 protease.
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PMID:The protease of human T-cell leukemia virus type-1 is a potential therapeutic target. 1750 36

Human T-lymphotropic virus type 1 (HTLV-1), the first known human retrovirus, induces various human diseases with a long latency period. The mechanism by which the virus causes diseases is still unknown. Studies indicate that viral replication is important at least for the development of HTLV-1 associated myelopathy, and therefore treatments based on our knowledge of human immunodeficiency virus type-1 (HIV-1) can be utilized to develop potent antiretroviral therapies targeting the replication enzymes reverse transcriptase, protease and integrase as well as the envelope glycoproteins. Furthermore, accessory gene products such as Tax and HBZ may also provide targets for chemotherapy. Treatment targeting these viral proteins may prevent the development of other HTLV-1-related diseases including adult T-cell leukemia, although such treatment may not be useful during the progression of the disease. This review describes the characteristics of HTLV-1 replication enzymes, envelope glycoproteins, and accessory proteins Tax and HBZ, and discusses the status of drug development strategies.
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PMID:Drug targets in human T-lymphotropic virus type 1 (HTLV-1) infection. 1927 4

Approximately 3% of all human T-lymphotropic virus type 1 (HTLV-1)-infected persons will develop a disabling inflammatory disease of the central nervous system known as HTLV-1-associated myelopathy/tropical spastic paraparesis, against which there is currently no efficient treatment. As correlation exists between the proviral load (PVL) and the clinical status of the carrier, it is thought that diminishing the PVL could prevent later occurrence of the disease. We have conducted a study combining valproate, an inhibitor of histone deacetylases, and azidothymidine, an inhibitor of reverse transcriptase, in a series of baboons naturally infected with simian T-lymphotropic virus type 1 (STLV-1), whose PVL was equivalent to that of HTLV-1 asymptomatic carriers. We show that the combination of drugs caused a strong decrease in the PVL and prevented the transient rise in PVL that is seen after treatment with histone deacetylases alone. We then demonstrate that the PVL decline was associated with an increase in the STLV-1-specific cytotoxic T-cell population. We conclude that combined treatment with valproate to induce viral expression and azidothymidine to prevent viral propagation is a safe and effective means to decrease PVL in vivo. Such treatments may be useful to reduce the risk of HAM/TSP in asymptomatic carriers with a high PVL.
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PMID:Highly active antiretroviral treatment against STLV-1 infection combining reverse transcriptase and HDAC inhibitors. 2058 83

Since human T-lymphotropic virus type 1 (HTLV-1)-associated diseases are associated with a high HTLV-1 load, reducing this load may treat or prevent disease. However, despite in vitro evidence that certain nucleoside/nucleotide analogue reverse transcriptase inhibitors (NRTIs) are active against HTLV-1, in vivo results have been disappointing. We therefore assayed the sensitivity of HTLV-1 primary isolates to a panel of RT inhibitors. HTLV-1 primary isolates were obtained, pre- and post- NRTI treatment, from patients with HTLV-1-associated myelopathy. Sensitivity to azidothymidine (AZT), lamivudine (3TC), tenofovir (TDF) and three phosphonated carbocyclic 2'-oxa-3'aza nucleosides (PCOANs) was assessed in a RT inhibitor assay. With the exception of 3TC, HTLV RT from primary isolates was less sensitive to all tested inhibitors than HTLV-1 RT from MT-2 cells. HTLV-1 RT from primary isolates and from chronically infected, transformed MT-2 cells was insensitive to 3TC. Sensitivity of primary isolates to RT inhibitors was not reduced following up to 12 months of patient treatment with AZT plus 3TC. The sensitivity of HTLV-1 primary isolates to NRTIs differs from that of cell lines and may vary among patients. Failure of NRTIs to reduce HTLV-1 viral load in vivo was not due to the development of phenotypic NRTI resistance. AZT and the three PCOANs assayed all consistently inhibited primary isolate HTLV-1 RT.
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PMID:Susceptibility of primary HTLV-1 isolates from patients with HTLV-1-associated myelopathy to reverse transcriptase inhibitors. 2199 43

The neurologic events related to antiretroviral therapy (ART) in HIV-infected ART-naive patients are relatively common. Side effects of ART and complications of HIV infection may overlap significantly. Establishing etiology of neurologic (neuropathy and neuropathic pain, changes in cognition, dementia, and myelopathy) and psychiatric (neurocognitive disorders, depression, anxiety, substance abuse and dependence, and others) complications can present a significant challenge. It has long been documented that neurologic and psychological side effects can occur with many of the agents used to treat HIV infection. Particularly, efavirenz from the non-nucleoside reverse transcriptase inhibitor (NNRTI) has been associated with neurologic and psychological complaints that may be difficult to differentiate from pre-existing mental illness, substance abuse, and HIV-related neuropsychiatric symptoms. Peripheral neuropathy (PN) of at least 6 different types is a well-known adverse effect of treatment with nucleoside reverse transcriptase inhibitors (NRTIs) in HIV-infected patients. Lack of dealing with early stages of neurologic and psychological side effects of HIV infection and Highly Active Anti-retroviral Therapy (HAART) are observed in daily practice. The purpose of this article is to identify the neurologic, neuropsychiatric and psychiatric complications related to HIV and anti-retroviral therapy, to discuss current knowledge about these disorders, and to suggest strategies for their diagnosis and management.
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PMID:Neuropathic and neurocongnitive complications of antiretroviral therapy among HIV-infected patients. 2401 99


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