Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.2.30 (PARP)
 13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aging is characterized by increased T cell lymphopenia, T cell dysfunction, and increased serum TNF levels. In this study, we have examined the role of TNF-induced apoptosis in T cell deficiency in lymphocytes from aged humans. The constitutive expression of TNF receptors (TNFRI and TNFRII) and the adapter molecules, including TNFR-associated death domain protein (TRADD), TNFR-associated factor 2 (TRAF-2), and receptor interacting protein (RIP), were analyzed both at the protein level by flow cytometry or Western blotting, and at the mRNA level using quantitative PCR or Northern blotting in lymphocytes from aged and young subjects. The susceptibility of T cells to undergo TNF-induced apoptosis was analyzed using terminal deoxynucleotidyltransferase-mediated UTP-end-labeling (TUNEL) and DNA ladder assays. Caspase (caspase-8 and caspase-3) activation was compared between aged and young subjects using Western blotting and colorimetric assays. In lymphocytes from aged humans, there was an increased susceptibility of CD4+ and CD8+ T cells to undergo TNF-alpha-induced apoptosis, as observed by TUNEL assay and DNA fragmentation ladder assay. Increased TNF-alpha-induced apoptosis was also observed in both CD45RA+ and CD45RO+ T cells from aging subjects. An increased constitutive expression of TNFRI and TRADD and decreased expression of TNFRII and TRAF-2 were observed in lymphocytes from aged as compared with young controls. In addition, there was an early and increased activation of caspases (caspase-8 and caspase-3) involved in TNFR/TNF signaling pathway, as evident by early cleavage of caspase-8, poly(ADP-ribose) polymerase (PARP), and caspase-3 substrate DEVD-p-nitroamilide NA. These data suggest that an increased TNF-alpha-induced apoptosis may play a role in T cell deficiency associated with human aging.
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PMID:Increased TNF-alpha-induced apoptosis in lymphocytes from aged humans: changes in TNF-alpha receptor expression and activation of caspases. 997 90

The mechanism of neuronal death in brain ischaemia remains unclear. Morphology, terminal transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) and immunohistochemistry for the pro-apoptotic enzyme caspase-3 (CASP3), for its substrates poly(ADP-ribose) polymerase (PARP) and the DNA-dependent protein kinase catalytic subunit (DNA-PKCS) and for poly(ADP-ribose) (PAR), an end-product of PARP activity, were used to investigate neuronal death in brain infarcts from 15 men and 20 women, aged 46-95 years. The infarcts varied in age from 18 h to several months. Neuronal death was characterized morphologically by cell shrinkage, cytoplasmic hypereosinophilia and moderate nuclear pyknosis with later chromatin dispersal and disintegration, but not features of apoptosis. Occasional apoptotic bodies were seen but these appeared to be related to inflammatory cells, endothelial cells and occasional glia, including satellite cells. Neurones within infarcts showed strong nuclear and cytoplasmic labelling for CASP3 during the first 2 days after infarction. Neuronal DNA-PKCS, PARP and poly(ADP-ribose) immunoreactivity was demonstrable in scattered neurones in and adjacent to infarcts for 18-24 h but thereafter declined to below detectable levels in most cases. TUNEL labelled cells towards the edge of the infarcts, particularly at 2-4 days, but most of the labelling could be prevented by preincubation of the sections in diethyl pyrocarbonate to inactivate endogenous nucleases. Between 3 days and 3 weeks, CASP3 and DNA-PKCS were detected in proliferating capillaries and CASP3, PARP and poly(ADP-ribose) in infiltrating macrophages. Our findings indicate that neuronal death in human brain infarcts has some of the early biochemical features of programmed cell death, with upregulation of CASP3 and rapid disappearance of DNA-PKCS and PARP. However, the morphological changes are not those of apoptosis, the DNA cleavage occurs relatively late, and some of the TUNEL is probably mediated by the release of endogenous endonucleases during protease or microwave pretreatment of the damaged tissue.
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PMID:Neuronal death in brain infarcts in man. 1073 67

Neuronal damage and dementia are common sequelae of HIV encephalitis. The mechanism by which HIV infection of CNS macrophages results in neuronal damage is not known. We examined the brains from 15 AIDS autopsies (8 with HIV encephalitis and 7 without) and 4 non-infected control autopsies for the presence of DNA strand breaks, for associated changes in the expression of the DNA repair enzymes KU80 and Poly (ADP-ribose) polymerase (PARP), and for accumulation of amyloid precursor protein (APP). Abundant DNA damage was observed with terminal transferase-mediated dUTP nick end-labeling (TUNEL), however, there was no morphologic evidence of significant neuroglial apoptosis. The DNA repair enzyme KU80 was immunocytochemically detectable in neuronal and glial cells in autopsy brains from patients with and without HIV encephalitis; however, in cases with HIV encephalitis the staining was more prominent than in the infected or non-infected controls without encephalitis. There was no difference in KU80 immunostaining in oligodendroglia from autopsies with and without encephalitis. Immunostaining for PARP was more intense in gray and white matter of cases with HIV encephalitis. No clear spatial relationship existed between expression of DNA repair enzymes and the spatial proximity of microglial nodules or HIV-infected macrophages. The cytoplasm of cortical and subcortical neurons immunostained for APP Stronger cortical neuronal APP staining was observed in cases without HIV encephalitis. Staining of deep gray matter neurons was similar, irrespective of the presence or absence of encephalitis. While foci of intense APP staining were noted in white matter not related to HIV infection, they were associated with foci of opportunistic infections (e.g. due to CMV or PML). We conclude that damaged DNA and altered patterns of expression of DNA repair proteins and APP are common findings in the brains of AIDS patients at autopsy, but do not have a spatial relationship to HIV-infected macrophages.
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PMID:Damage and repair of DNA in HIV encephalitis. 1108 73

Epidemiological and clinical data suggest that selenium may prevent prostate cancer, but the biological effects of selenium on normal or malignant prostate cells are not well known. We evaluated the effects of sodium selenite (Na2SeO3) or l-selenomethionine (SeMet) on monolayer and anchorage-independent growth in a series of normal primary prostate cultures (epithelial, stromal, and smooth muscle) and prostate cancer cell lines (LNCaP, PC-3, and DU145). We observed differential, dose-dependent growth inhibition and apoptosis within prostate cancer cells (compared with normal prostate cells) treated with 1-500 microM of Na2SeO3 or SeMet. Na2SeO3 more potently inhibited growth at any given concentration. The androgen-responsive LNCaP cells were the most sensitive to selenium growth suppression (IC50s at 72 h for Na2SeO3 and SeMet were 0.2 and 1.0 microM, respectively). Growth of the primary prostate cells virtually was not suppressed (IC50s at 72 h for Na2SeO3 and SeMet were 22-38 and >500 microM, respectively). We also observed that DNA condensation and DNA fragmentation (terminal deoxynucleotidyltransferase dUTP nick end labeling/fluorescence-activated cell sorting) were elevated in selenium-treated cells and that activated caspase-3 colocalized with terminal deoxynucleotidyltransferase dUTP nick end labeling-stained cells by immunofluorescence. Higher basal poly(ADP-ribose) polymerase (PARP) expression levels and PARP cleavage (a substrate for caspase-3) were observed during apoptosis in tumor cells, compared with normal cells. Selective tumor cell death was associated with an increase in sub-G0-G1 cells after propidium iodide staining and fluorescence-activated cell sorting analysis. SeMet caused an increase in arrest in the G2-M phase of the cell cycle selectively in cancer cells. Inhibition of cancer cell growth by SeMet was associated with phosphorylation of P-Tyr15-p34/cdc2, which caused growth arrest in the G2-M phase. Anchorage-independent growth of prostate cancer cells in soft agar was sensitive to selenium. Our results suggest that Na2SeO3 is the more potent inducer of apoptosis in normal and cancer prostate cells. Our SeMet results involving PARP and G2-M cell-cycle arrest (cited above) indicate that SeMet selectively induces apoptosis in cancer but not primary cells of the human prostate. Our overall findings are relevant to the molecular mechanisms of selenium actions on prostate carcinogenesis and help demonstrate the selective, dose-dependent effects of selenium (especially SeMet) on prostate cancer cell death and growth inhibition.
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PMID:Selenium effects on prostate cell growth. 1109 24

Alveolar macrophages (AMs) are the principal target cells of silica and occupy a key position in the pathogenesis of silica-related diseases. Silica has been found to induce apoptosis in AMs, whereas its underlying mechanisms involving the initiation and execution of apoptosis are largely unknown. The main objective of the present study was to examine the form of cell death caused by silica and the mechanisms involved. Silica-induced apoptosis in AMs was evaluated by terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling assay and cell cycle/DNA content analysis. The elevated level of reactive oxygen species (ROS), caspase-9 and caspase-3 activation, and poly(ADP-ribose) polymerase (PARP) cleavage in silica-treated AMs were also determined. The results showed that there was a temporal pattern of apoptotic events in silica-treated AMs, starting with ROS formation and followed by caspase-9 and caspase-3 activation, PARP cleavage, and DNA fragmentation. Silica-induced apoptosis was significantly attenuated by a caspase-3 inhibitor, N-acetyl-Asp-Glu-Val-Asp aldehyde, and ebselen, a potent antioxidant. These findings suggest that apoptosis is an important form of cell death caused by silica exposure in which the elevated ROS level that results from silica exposure may act as an initiator, leading to caspase activation and PARP cleavage to execute the apoptotic process.
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PMID:Reactive oxygen species and caspase activation mediate silica-induced apoptosis in alveolar macrophages. 1113 90

Expression of the lytic cycle genes of Epstain-Barr virus (EBV) is induced in type I Burkitt's lymphoma-derived cells by treatment with phorbol esters (e.g., phorbol myristate acetate [PMA]), anti-immunoglobulin, or the cytokine transforming growth factor beta (TGF-beta). Concomitantly, all these agents induce apoptosis as judged by a sub-G1 fluorescence-activated cell sorter (FACS) profile, proteolytic cleavage of poly(ADP-ribose) polymerase (PARP) and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) staining. However, caspase activation is not required for induction of the lytic cycle since the latter is not blocked by the caspase inhibitor ZVAD. Furthermore, not all agents that induce apoptosis in these cultures (for example, cisplatin and ceramide) induce the EBV lytic programme. Although it is closely associated with the lytic cycle, apoptosis is neither necessary nor sufficient for its activation. Multiparameter FACS analysis of cultures treated with PMA, anti-Ig, or TGF-beta revealed BZLF1-expressing cells distributed in different phases of the cell cycle according to which inducer was used. However, BZLF1-positive cells did not appear to undergo apoptosis and accumulate with a sub-G1 DNA content, irrespective of the inducer used. This result, which suggests that lytic gene expression is protective, was confirmed and extended by immunofluorescence staining doubled with TUNEL analysis. BZLF1- and also gp350-expressing cells were almost always shown to be negative for TUNEL staining. Similar experiments using EBV-positive and -negative subclones of Akata BL cells carrying an episomal BZLF1 reporter plasmid confirmed that protection from apoptosis was associated with the presence of the EBV genome. Finally, treatment with phosphonoacetic acid or acyclovir prior to induction with PMA, anti-Ig, or TGF-beta blocked the protective effect in Mutu-I cells. These data suggest that a late gene product(s) may be particularly important for protection against caspase activity and cell death.
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PMID:Activators of the Epstein-Barr virus lytic program concomitantly induce apoptosis, but lytic gene expression protects from cell death. 1116 Jul 43

Cadmium (Cd) is a well-known environmental carcinogen and immunotoxin. Currently the direct cytotoxic effects of Cd on thymocytes are largely unexplored. The main objective of the present study was to investigate the apoptogenic property of Cd and the mechanisms involved, using primary cultured mouse thymocytes as a model. Cd-induced apoptosis in thymocytes was studied by TdT-mediated dUTP nick end-labeling assay and DNA gel electrophoresis. The results showed that Cd was able to cause apoptosis in mouse thymocytes in a time- and dose-dependent manner. Moreover, Cd exposure led to a rapid and sustained intracellular calcium (Ca2+) elevation, followed by caspase-3 activation and PARP cleavage, all of which preceded the characteristic DNA fragmentation. BAPTA-AM, a specific intracellular Ca2+ chelator, abolished Cd-induced Ca2+ overloading and subsequently inhibited caspase-3 activation, PARP cleavage, and apoptosis. It is believed that intracellular Ca2+ elevation may trigger caspase-3 activation either through mitochondria or through activation of Ca2+-dependent protease in Cd-treated thymocytes. Results from this study thus provide new information for a better understanding of the immunotoxic and immunomodulatory effects of Cd.
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PMID:Critical role of calcium overloading in cadmium-induced apoptosis in mouse thymocytes. 1118 Nov 7

Mucopolysaccharidosis (MPS) Type VI (Maroteaux-Lamy Disease) is the lysosomal storage disease characterized by deficient arylsulfatase B activity and the resultant accumulation of dermatan sulfate-containing glycosaminoglycans (GAGs). A major feature of this and other MPS disorders is abnormal cartilage and bone development leading to short stature, dysostosis multiplex, and degenerative joint disease. To investigate the underlying cause(s) of degenerative joint disease in the MPS disorders, articular cartilage and cultured articular chondrocytes were examined from rats and cats with MPS VI. An age-progressive increase in the number of apoptotic chondrocytes was identified in the MPS animals by terminal transferase nick-end translation (TUNEL) staining and by immunohistochemical staining with anti-poly (ADP-ribose) polymerase (PARP) antibodies. Articular chondrocytes grown from these animals also released more nitric oxide (NO) and tumor necrosis factor alpha (TNF-alpha) into the culture media than did control chondrocytes. Notably, dermatan sulfate, the GAG that accumulates in MPS VI cells, induced NO release from normal chondrocytes, suggesting that GAG accumulation was responsible, in part, for the enhanced cell death in the MPS cells. Coculture of normal chondrocytes with MPS VI cells reduced the amount of NO release, presumably because of the release of arylsulfatase B by the normal cells and reuptake by the mutant cells. As a result of the enhanced chondrocyte death, marked proteoglycan and collagen depletion was observed in the MPS articular cartilage matrix. These results demonstrate that MPS VI articular chondrocytes undergo cell death at a higher rate than normal cells, because of either increased levels of dermatan sulfate and/or the presence of inflammatory cytokines in the MPS joints. In turn, this leads to abnormal cartilage matrix homeostasis in the MPS individuals, which further exacerbates the joint deformities characteristic of these disorders.
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PMID:Articular chondrocytes from animals with a dermatan sulfate storage disease undergo a high rate of apoptosis and release nitric oxide and inflammatory cytokines: a possible mechanism underlying degenerative joint disease in the mucopolysaccharidoses. 1155 79

Leishmania donovani promastigotes introduced into the bloodstream by sandfly vectors, are exposed to reactive oxygen species like H2O2 during phagocytosis by the host macrophages. H2O2 can induce promastigote death, but the mechanism of induction of this death is not known. Studies presented in this paper demonstrate that exposure to 4 mM H2O2 results in a pattern of promastigote death that shares many features with metazoan apoptosis. Motility and cell survival in these parasites show a gradual decline with increasing doses of H2O2. Features common to metazoan apoptosis, such as nuclear condensation, DNA fragmentation with accompanying DNA ladder formation and loss of cell volume, are observed after exposure to 4 mM H2O2. Within 30 minutes of the exposure, there is a significant increase in the ability of the cell lysates to cleave the fluorogenic tetrapeptide acetyl-Asp-Glu-Val-Asp-7-amino-4-trifluoromethyl coumarin, which is a substrate for the CED-3/CPP32 group of proteases. Pretreatment of cells with a specific inhibitor of CED-3/CPP32 group of proteases, Z-DEVD-FMK, reduces the number of cells showing apoptosis-like features, prevents DNA breakage and inhibits cleavage of a PARP-like protein. Activation of the caspase-like proteases is followed at 2 hours by the cleavage of a poly(ADP)ribose-polymerase-like protein and a reduction in intracellular glutathione concentration. DNA breakdown as detected by TdT labelling of cells and agarose gel electrophoresis is visible at 6 hours. Taken together, the above data show for the first time that there is a distinct pathway for apoptosis-like death in L. donovani.
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PMID:Hydrogen peroxide induces apoptosis-like death in Leishmania donovani promastigotes. 1155 54

African swine fever (ASF) is an asymptomatic infection of warthogs and bushpigs, which has become an emergent disease of domestic pigs, characterized by hemorrhage, lymphopenia, and disseminated intravascular coagulation. It is caused by a large icosohedral double-stranded DNA virus, African swine fever virus (ASFV), with infection of macrophages well characterized in vitro and in vivo. This study shows that virulent isolates of ASFV also infect primary cultures of porcine aortic endothelial cells and bushpig endothelial cells (BPECs) in vitro. Kinetics of early and late gene expression, viral factory formation, replication, and secretion were similar in endothelial cells and macrophages. However, ASFV-infected endothelial cells died by apoptosis, detected morphologically by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling and nuclear condensation and biochemically by poly(ADP-ribose) polymerase (PARP) cleavage at 4 h postinfection (hpi). Immediate-early proinflammatory responses were inhibited, characterized by a lack of E-selectin surface expression and interleukin 6 (IL-6) and IL-8 mRNA synthesis. Moreover, ASFV actively downregulated interferon-induced major histocompatibility complex class I surface expression, a strategy by which viruses evade the immune system. Significantly, Western blot analysis showed that the 65-kDa subunit of the transcription factor NF-kappaB, a central regulator of the early response to viral infection, decreased by 8 hpi and disappeared by 18 hpi. Both disappearance of NF-kappaB p65 and cleavage of PARP were reversed by the caspase inhibitor z-VAD-fmk. Interestingly, surface expression and mRNA transcription of tissue factor, an important initiator of the coagulation cascade, increased 4 h after ASFV infection. These data suggest a central role for vascular endothelial cells in the hemorrhagic pathogenesis of the disease. Since BPECs infected with ASFV also undergo apoptosis, resistance of the natural host must involve complex pathological factors other than viral tropism.
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PMID:African swine fever virus infection of porcine aortic endothelial cells leads to inhibition of inflammatory responses, activation of the thrombotic state, and apoptosis. 1158 5


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