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 anti-HIV agent MAP30 (Momordica anti-HIV protein, 30 kDa) inhibits the proliferation of BC-2, an AIDS-related primary effusion lymphoma (PEL) cell line derived from an AIDS patient. BC-2 cells are latently infected with Kaposi's sarcoma-associated herpes virus (KSHV), also known as human herpes virus 8 (HHV8). We examined the effect of MAP30 on the expression of viral and cellular genes in BC-2 during latent and lytic states of the viral life cycle. By Northern analysis and RT-PCR, we found that MAP30 downregulates the expression of viral cyclin D (vCD), viral interleukin-6 (vIL-6), and viral FLIP (vFLIP), genes involved in cell cycle regulation, viral pathogenesis, and apoptosis. By pathway-specific cDNA microarray analysis, we found that BC-2 cells express high levels of egr-1, ATF-2, hsp27, hsp90, IkappaB, mdm2, skp1, and IL-2, cellular genes involved in mitogenesis, tumorigenesis, and inhibition of apoptosis in NFkappaB and p53 signaling pathways. These results define for the first time the specific cellular pathways involved in AIDS-related tumorigenesis and suggest specific novel targets for the treatment. Furthermore, we found that MAP30 downregulates the expression of egr-1, ATF-2, hsp27, hsp90, IkappaB, mdm2, and Skp1, while it upregulates the pro-apoptotic-related genes Bax, CRADD, and caspase-3. Thus, MAP30 modulates the expression of both viral and cellular genes involved in KS pathogenesis. These results provide valuable insight into the molecular mechanisms of MAP30 anti-KS action and suggest its utility as a therapeutic agent against AIDS-related tumors.
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PMID:Anti-HIV agent MAP30 modulates the expression profile of viral and cellular genes for proliferation and apoptosis in AIDS-related lymphoma cells infected with Kaposi's sarcoma-associated virus. 1157 62

CD95 plays a critical role in the homeostasis of the immune system, and has been reported to participate in T cell death during HIV infection. Here we report that the response to CD3-TCR stimulation of CD4(+) T cells from HIV-infected individuals and CD4(+) T cells from healthy donors incubated in vitro with HIV-1(Lai) depends on the manner the CD3-TCR complex is engaged. While stimulation by anti-CD3 antibodies in solution induced CD4 T cell apoptosis both in the absence or presence of anti-CD95 antibodies, stimulation by immobilized anti-CD3 antibodies rendered CD4(+) T cells resistant to CD95-mediated death and led to increased CD4 T cell proliferation in response to CD95 ligation. CD95 ligation of CD4(+) T cells led to the activation of caspases, while costimulation induced by anti-CD3 and anti-CD95 mAb prevented the full processing of caspase-3 and caspase-8. Proliferation of CD4(+) T cells induced by CD3-TCR and CD95 costimulation was decreased by treatments with a caspase-1 inhibitor or with neutralizing antibodies to IL-1ss, indicating a requirement for caspase-1-mediated IL-1beta processing and secretion. Our findings suggest a novel mechanism whereby in addition to its role in inducing T cell apoptosis, CD95 signaling during HIV infection may also provide a costimulatory signal leading to an enhancement of CD4 T cell proliferation in response to CD3-TCR complex engagement.
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PMID:Role of CD95-activated caspase-1 processing of IL-1beta in TCR-mediated proliferation of HIV-infected CD4(+) T cells. 1174 71

Pigtailed macaques infected with a virulent human immunodeficiency virus-2 (HIV-2) strain develop renal thrombotic microangiopathy (TMA), which morphologically resembles aspects of human HIV-associated TMA. Apoptotic cell death of microvascular endothelial cells might be a pathogenetic clue to this disease. For defining further the pattern of cellular injury in this model, serial kidney sections of 58 macaques infected with HIV-2 and 7 uninfected controls were studied by routine microscopy, terminal deoxynucleotidyl-transferase-mediated dUTP nick-end labeling (TUNEL), 4',6-diamidino-2-phenylindole staining, and immunohistochemistry for single-stranded DNA, p53, the Wilms' tumor suppressor gene-1 peptide product, caspase-3, and the proliferation marker Ki67. Selected cases were further evaluated by in situ end labeling and transmission electron microscopy. Kidneys of 13 HIV-2-infected animals contained a pattern of cellular injury, which was characterized by (1) nuclear swelling with an ultrastructural morphology different from apoptotic nuclei, (2) sharply demarcated areas of renal cells with chromatin nicks (TUNEL positive) and single-stranded DNA, (3) absence of an inflammatory or proliferative response, (4) upregulation of p53 and loss of at least one cellular differentiation marker (Wilms' tumor suppressor gene-1), (5) a tight correlation with the diagnosis of renal TMA, and (6) a contrast between profound changes in the renal cellular morphology and the apparently unaffected clinical condition of the host. This pattern of injury, which shares some features of both apoptotic and oncotic necrosis, might be involved in the pathogenesis of HIV-associated renal TMA in this model.
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PMID:Cellular injury associated with renal thrombotic microangiopathy in human immunodeficiency virus-infected macaques. 1180 64

Human solid tumors contain hypoxic regions that have considerably lower oxygen tension than normal tissues. These impart resistance to radiotherapy and anticancer chemotherapy, as well as predisposing to increased tumor metastases. To develop a potentially therapeutic protein drug highly specific for solid tumors, we constructed fusion proteins selectively stabilized in hypoxic tumor cells. A model fusion protein, oxygen-dependent degradation (ODD)-beta-galactosidase (beta-Gal), composed of a part of the ODD domain of hypoxia-inducible factor-1alpha fused to beta-Gal, showed increased stability in cultured cells under a hypoxia-mimic condition. When ODD-beta-Gal was further fused to the HIV-TAT protein transduction domain (TAT(47-57)) and i.p. injected to a tumor-bearing mouse, the biologically active fusion protein was specifically stabilized in solid tumors but was hardly detected in the normal tissue. Furthermore, when wild-type (WT) caspase-3 (Casp3(WT)) or its catalytically inactive mutant was fused to TAT-ODD and i.p. injected to a tumor-bearing mouse, the size of tumors was reduced by the administration of TAT-ODD-Casp3(WT) but not by TAT-ODD-mutant Casp3. TAT-ODD-Casp3(WT) did not cause any obvious side effects on tumor-bearing mice, suggesting specific stabilization and activation of the fusion protein in the hypoxic tumor cells. These results suggest that the combination of protein therapy using a cytotoxic TAT-ODD fusion protein with radiotherapy and chemotherapy may provide a new strategy for annihilating solid tumors.
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PMID:Antitumor effect of TAT-oxygen-dependent degradation-caspase-3 fusion protein specifically stabilized and activated in hypoxic tumor cells. 1192 18

Many patients infected with human immunodeficiency virus-1 (HIV-1) develop a syndrome of neurologic deterioration known as HIV-associated dementia (HAD). Neurons are not productively infected by HIV-1; thus, the mechanism of HIV-induced neuronal injury remains incompletely understood. Several investigators have observed evidence of neuronal injury, including dendritic degeneration, and apoptosis in CNS tissue from patients with HAD. Caspase enzymes, proteases associated with the process of apoptosis, are synthesized as inactive proenzymes and are activated in a proteolytic cascade after exposure to apoptotic signals. Here we demonstrate that HAD is associated with active caspase-3-like immunoreactivity that is localized to the soma and dendrites of neurons in affected regions of the human brain. Additionally, the cascade of caspase activation was studied using an in vitro model of HIV-induced neuronal apoptosis. Increased caspase-3 proteolytic activity and mitochondrial release of cytochrome c were observed in cerebrocortical cultures exposed to the HIV coat protein gp120. Specific inhibitors of both the Fas/tumor necrosis factor-alpha/death receptor pathway and the mitochondrial caspase pathway prevented gp120-induced neuronal apoptosis. Caspase inhibition also prevented the dendrite degeneration observed in vivo in transgenic mice with CNS expression of HIV/gp120. These findings suggest that pharmacologic interventions aimed at the caspase enzyme pathways may be beneficial for the prevention or treatment of HAD.
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PMID:Caspase cascades in human immunodeficiency virus-associated neurodegeneration. 1201 21

We recently reported that the T-cell receptor (TCR)-zeta chain is cleaved by caspase-3 and -7 in apoptotic T lymphocytes or in a cell-free system. We report here that the zeta chain is also a direct substrate for granzyme B (GrB) proteolytic activity. Loss in expression of TCR-zeta was observed in Jurkat T leukemic cells treated by a combination of GrB and a replication-deficient adenovirus. Although the apoptosis initiated in these cells by GrB was significantly reduced by the pancaspase inhibitor Z-VAD-FMK, TCR-zeta degradation was not prevented. These findings suggest that the GrB-mediated degradation of TCR-zeta chain can proceed despite the efficient inhibition of caspase activity. An in vitro translated TCR-zeta product was efficiently cleaved by GrB, which suggests that the TCR-zeta protein is a direct substrate for GrB. As assessed by site-directed mutagenesis, the activity of GrB was directed toward aspartic acid residues that were different from those of recombinant caspase-3. Whereas caspase-3 cleavage products appear to accumulate, the GrB-generated products seem to undergo further degradation, which suggests the presence of multiple GrB-specific cleavage sites within the TCR-zeta protein. These findings suggest that the TCR-zeta protein in target T lymphocytes serves as a substrate for the proteolytic activities that are featured by the two major mechanisms of cytotoxicity: death receptor pathways mediated by caspases and granule exocytosis mediated by direct GrB activity or GrB-activated caspases. TCR-zeta protein degradation may be of significance in cytotoxic mechanisms directed against T cells infected with viruses, such as HIV-1, in which the TCR-zeta protein is used for viral pathogenesis.
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PMID:Granzyme B-mediated degradation of T-cell receptor zeta chain. 1220 35

The human immunodeficiency virus type 1 (HIV-1) envelope protein gp120 has been implicated in the pathogenesis of HIV-1 dementia. Thus, inhibition of gp120 activity could reduce HIV toxicity in the brain. We have used primary cultures of rat cerebellar granule cells to examine mechanisms whereby gp120 causes cell death and to characterize neuroprotective agents. gp120 induced a time- and concentration-dependent apoptotic cell death, which was caspase-3-mediated but caspase-1 independent, and was totally blocked by the irreversible caspase-3-like protease inhibitor N-acetyl-Asp-Glu-Val-Asp-chloromethylketone. Caspase-3 activation was observed only in neurons that internalize gp120, indicating that internalization is key to gp120 toxicity. Because brain-derived neurotrophic factor (BDNF) prevents caspase-3-mediated neuronal cell death, we examined whether BDNF could prevent gp120-mediated apoptosis. Preincubation of neurons with BDNF before the addition of gp120 reduced caspase-3 activation, and consequently rescued 80% of neurons from apoptosis. Most importantly, BDNF reduced the levels of CXC chemokine receptor-4 (CXCR4), a receptor that mediates HIV-1 gp120-induced apoptosis. This effect correlated with the ability of BDNF to reduce gp120 internalization and apoptosis. Moreover, BDNF blocked the neurotoxic effect of stromal-derived factor-1alpha, a natural ligand for CXCR4, further establishing a correlation between neuroprotection and downregulation of CXCR4. We propose that BDNF may be a valid therapy to slow down the progression of HIV/gp120-mediated neurotoxicity.
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PMID:Brain-derived neurotrophic factor inhibits human immunodeficiency virus-1/gp120-mediated cerebellar granule cell death by preventing gp120 internalization. 1284 75

The anti-HIV drug 3'-azido-3'-deoxythymidine (AZT) is the drug of choice for preventing maternal-fetal HIV transmission during pregnancy. Our aim was to assess the cytotoxic effects of AZT on human placenta in vitro. The mechanisms of AZT-induced effects were investigated using JEG-3 choriocarcinoma cells and primary explant cultures from term and first-trimester human placentas. Cytotoxicity measures included trypan blue exclusion, MTT, and reactive oxygen species (ROS) assays. Apoptosis was measured with an antibody specific to cleaved caspase-3 and by rescue of cells by the general caspase inhibitor Boc-D-FMK. The effect of AZT on the activities of glutathione-S-transferase, beta-glucuronidase, UDP-glucuronosyl transferase, cytochrome P450 (CYP) 1A, and CYP reductase (CYPR) in the placenta was assessed using biochemical assays and immunoblotting. AZT increased ROS levels, decreased cellular proliferation rates, was toxic to mitochondria, and initiated cell death by a caspase-dependent mechanism in the human placenta in vitro. In the absence of serum, the effects of AZT were amplified in all the models used. AZT also increased the amounts of activity of GST, beta-glucuronidase, and CYP1A, whereas UGT and CYPR were decreased. We conclude that AZT causes apoptosis in the placenta and alters metabolizing enzymes in human placental cells. These findings have implications for the safe administration of AZT in pregnancy with respect to the maintenance of integrity of the maternal-fetal barrier.
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PMID:3'-azido-3'-deoxythymidine (AZT) induces apoptosis and alters metabolic enzyme activity in human placenta. 1455 Jul 50

TNF-alpha is a pro-inflammatory cytokine that plays a key role in disorders due to HIV-1 infection and replication such as Kaposi sarcoma, wasting, aphthous ulcerations and progression to AIDS. The controversial drug thalidomide is anti-inflammatory, anti-angiogenic and a selective inhibitor of TNF-alpha that is being studied as a treatment for HIV-1-related disorders, immune disorders and cancer. The cellular and molecular mechanism of thalidomide is unclear despite renewed clinical interest in the drug. Previous data from this laboratory indicate that thalidomide decreases cell growth and cell-cell interactions of human T leukemic cells. The specific aim of the present study is to determine whether thalidomide administration induces cell death via apoptosis. Low dose thalidomide treatment of human T leukemic cells exhibited rapid increases in caspase-3 activity, annexin V-FITC binding and DNA disintegration that is characteristic of apoptosis. These data indicate that low doses of thalidomide signal human T leukemic cells to die by apoptosis, which is a possible method of altering inflammatory cells and inflammatory activities.
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PMID:Exposure to the anti-TNF-alpha drug thalidomide induces apoptotic cell death in human T leukemic cells. 1468 94

TNF-related apoptosis-inducing ligand (TRAIL) is a type II integral membrane protein that interacts with multiple receptors and cell types including neurons. In this report, TRAIL protein levels were increased in human monocyte-derived macrophages (MDM) after HIV-1 infection and immune activation. In HIV-1 encephalitic (HIVE) human brain tissue, TRAIL-expressing macrophages were found in association with active caspase-3 positive neurons. Cytotoxic TRAIL receptors 1 and 2 were expressed on neurons in primary human fetal cultures and HIV-1 encephalitic brain tissue. Furthermore, TRAIL induced a dose-dependent effect on neuronal apoptosis. These results support a role for TRAIL in mononuclear phagocyte (MP)-mediated neurotoxicity in HIV-1-associated dementia (HAD).
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PMID:TNF-related apoptosis-inducing ligand mediates human neuronal apoptosis: links to HIV-1-associated dementia. 1497 93


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