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:2.4.2.30 (PARP)
13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Incubation of cultured rat hepatocytes with sodium nitroprusside or SIN-1, two nitric oxide (NO) donors, inhibited the mitogenic action of hepatocyte growth factor in a dose-dependent manner. The addition of 100 microM reduced hemoglobin, which is known to absorb NO, or the presence of 20 microM 1,5-isoquinolinediol, a poly(ADP-ribose) polymerase (PARP) inhibitor, decreased the cytostatic effects of SIN-1. By labeling the hepatocytes with [2-3H]adenine we studied whether nitric oxide induces ADP-ribosylation of proteins in a whole-cell system. At 0.4 mM, sodium nitroprusside increased the [3H]adenine labeling of two proteins of 116 and 130-135 kDa. This effect was time-dependent and was detected after 2 h. Only the 116-kDa protein was recognized by three different antibodies against poly (ADP-ribose) polymerase in Western blot assays. These results demonstrate that NO has antimitogenic effects in cultured hepatocytes and that its action could be mediated by PARP activation.
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PMID:Nitric oxide inhibits DNA synthesis and induces activation of poly(ADP-ribose) polymerase in cultured rat hepatocytes. 889 65

To clarify the mechanisms of nitric oxide (NO)-induced cell death in human neuronal cells, we examined effects of NO donors such as sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP) on activities of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and poly(ADP-ribose) polymerase (PARP) in human neuroblastoma cell line, SH-SY5Y. SNP-induced [32P]ADP-ribosylation of 113-kDa and 37-kDa proteins in SH-SY5Y cells. Treatment with PARP inhibitors such as 3-aminobenzamide and 1,5-isoquinolinediol partially prevented SNAP-induced cell death of SH-SY5Y. In purified GAPDH (37-kDa protein), SNP- and SNAP-induced enhancement of [32P]ADP-ribosylation, and inhibition of GAPDH activity. These results suggest that NO-induced cell death in human neuroblastoma SH-SY5Y cells possibly involves in covalent modifications such as ADP-ribosylation in PARP and GAPDH.
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PMID:Possible involvement of ADP-ribosylation of particular enzymes in cell death induced by nitric oxide-donors in human neuroblastoma cells. 904 62

Poly(ADP-ribose)polymerase (PARP) is an abundant nuclear enzyme activated by DNA breaks. PARP is generally believed to play a role in maintaining the integrity of the genome in eukaryote cells via anti-recombinogenic activity by preventing inappropriate homologous recombination reactions at DNA double-strand breaks. While inhibition of PARP reduces non-homologous recombination, at the same time it stimulates sister chromatid exchange and intrachromosomal homologous recombination. Here we report that the inhibition of PARP with 100 microg/ml (0.622 mM) 1,5-isoquinolinediol results in an average 4.6-fold increase in the frequency of extrachromosomal homologous recombination between two linearized plasmids carrying herpes simplex virus thymidine kinase genes inactivated by non-overlapping mutations, in mouse Ltk-fibroblasts. These results are in disagreement with the previously reported observation that PARP inhibition had no effect on extrachromosomal homologous recombination in Ltk-cells.
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PMID:Inhibition of poly(ADP-ribose)polymerase stimulates extrachromosomal homologous recombination in mouse Ltk-fibroblasts. 1053 64

Gene targeting is a technique that allows the introduction of predefined alterations into chromosomal DNA. It involves a homologous recombination reaction between the targeted genomic sequence and an exogenous targeting vector. In theory, gene targeting constitutes the ideal method of gene therapy for single gene disorders. In practice, gene targeting remains extremely inefficient for at least two reasons: very low frequency of homologous recombination in mammalian cells and high proficiency of the mammalian cells to randomly integrate the targeting vector by illegitimate recombination. One known method to improve the efficiency of gene targeting is inhibition of poly(ADP-ribose)polymerase (PARP). It has been shown that PARP inhibitors, such as 3-methoxybenzamide, could lower illegitimate recombination, thus increasing the ratio of gene targeting to random integration. However, the above inhibitors were reported to decrease the absolute frequency of gene targeting. Here we show that treatment of mouse Ltk cells with 1,5-isoquinolinediol, a recent generation PARP inhibitor, leads to an increase up to 8-fold in the absolute frequency of gene targeting in the correction of the mutation at the stable integrated HSV tk gene.
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PMID:1,5-isoquinolinediol increases the frequency of gene targeting by homologous recombination in mouse fibroblasts. 1268 32

We hypothesize that poly (ADP-ribosyl)ation, that is, poly (ADP-ribose) polymerase (PARP)-dependent transfer of ADP-ribose moieties from NAD to nuclear proteins, plays a role in diabetic nephropathy. We evaluated whether PARP activation is present and whether two unrelated PARP inhibitors, 3-aminobenzamide (ABA) and 1,5-isoquinolinediol (ISO), counteract overexpression of endothelin-1 (ET-1) and ET receptors in the renal cortex in short-term diabetes. The studies were performed in control rats and streptozotocin-diabetic rats treated with/without ABA or ISO (30 and 3 mg x kg(-1) x day(-1), intraperitoneally, for 2 weeks after 2 weeks of diabetes). Poly (ADP-ribose) immunoreactivity was increased in tubuli, but not glomeruli, of diabetic rats and this increase was corrected by ISO, whereas ABA had a weaker effect. ET-1 concentration (ELISA) was increased in diabetic rats, and this elevation was blunted by ISO. ET-1, ET(A), and ET(B) mRNA (ribonuclease protection assay), but not ET-3 mRNA (RT/PCR), abundance was increased in diabetic rats, and three variables were, at least, partially corrected by ISO. ABA produced a trend towards normalization of ET-1 concentration and ET-1, ET(A), and ET(B) mRNA abundance, but the differences with untreated diabetic group were not significant. Poly(ADP-ribosyl)ation is involved in diabetes-induced renal overexpression of ET-1 and ET receptors. PARP inhibitors could provide a novel therapeutic approach for diabetic complications including nephropathy, and other diseases that involve the endothelin system.
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PMID:Diabetes-induced overexpression of endothelin-1 and endothelin receptors in the rat renal cortex is mediated via poly(ADP-ribose) polymerase activation. 1282 90

Poly(adenosine diphosphate-ribose) polymerase (PARP) has recently been characterized as a key regulator of cell death-survival transcriptional programs associated with stress and inflammation. Possible participation of this enzyme in the response of tumors to photodynamic therapy (PDT) was investigated in this study. Immunohistochemical analysis of mouse FsaR tumors treated by PDT based on photosensitizers Photofrin or 5,10,15,20-tetra-(m-hydroxyphenyl)chlorine (mTHPC) revealed a strong positive staining for PARP product poly(ADP-ribose) at 30 min and 1 h after PDT, respectively, and even more intense positivity at 2 h after PDT with both photosensitizers. Flow cytometry-based examination showed the induction of poly-ADP-ribosylation in FsaR tumors at 30 min after PDT, with a trend for a further increase in the intensity by 2 h after PDT in both cancer cells and tumor-associated leukocytes. In FsaR cells treated in vitro by mTHPC-based PDT, flow cytometric analysis indicated that the activation of PARP concentrated in cells undergoing apoptosis and reached a maximum by 30 min after PDT. The administration of PARP inhibitors, 3-aminobenzamide or 1,5-isoquinolinediol, to FsaR tumor-bearing mice before PDT light treatment increased the resistance of these tumors to PDT. PARP appears to control the balance between apoptotic and necrotic cell death in PDT-treated tumors and regulate the progression of PDT-induced inflammatory or innate immune response.
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PMID:Activation of poly(adenosine diphosphate-ribose) polymerase in mouse tumors treated by photodynamic therapy. 1462 69

Oxidative and nitrosative stress play a key role in the pathogenesis of diabetic neuropathy, but the mechanisms remain unidentified. Here we provide evidence that poly(ADP-ribose) polymerase (PARP) activation, a downstream effector of oxidant-induced DNA damage, is an obligatory step in functional and metabolic changes in the diabetic nerve. PARP-deficient (PARP(-/-)) mice were protected from both diabetic and galactose-induced motor and sensory nerve conduction slowing and nerve energy failure that were clearly manifest in the wild-type (PARP(+/+)) diabetic or galactose-fed mice. Two structurally unrelated PARP inhibitors, 3-aminobenzamide and 1,5-isoquinolinediol, reversed established nerve blood flow and conduction deficits and energy failure in streptozotocin-induced diabetic rats. Sciatic nerve immunohistochemistry revealed enhanced poly(ADP-ribosyl)ation in all experimental groups manifesting neuropathic changes. Poly(ADP-ribose) accumulation was localized in both endothelial and Schwann cells. Thus, the current work identifies PARP activation as an important mechanism in diabetic neuropathy and provides the first evidence for the potential therapeutic value of PARP inhibitors in this devastating complication of diabetes.
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PMID:Role of poly(ADP-ribose) polymerase activation in diabetic neuropathy. 1498 56

We hypothesize that poly(ADP-ribose) polymerase (PARP) activation is an important mechanism in the oxidative stress-related development of diabetic retinopathy. In the experiments reported here, we evaluated if: a) PARP activation is present in the retina in short-term diabetes; and b) PARP inhibitors, 3-aminobenzamide and 1,5-isoquinolinediol, counteract diabetes- and hypoxia-induced retinal VEGF formation. In vivo studies were performed in control and streptozotocin-diabetic rats treated with/without 3-aminobenzamide or 1,5-isoquinolinediol (30 and 3 mg/kg per day, intraperitoneally, for 2 weeks after 2 weeks of diabetes). In vitro studies were performed in human retinal pigment epithelial cells exposed to normoxia or hypoxia with/without 3-aminobenzamide and 1,5-isoquinolinediol at 200 and 2 micro M. Retinal immunostaining for poly(ADP-ribose) was increased and NAD concentration reduced in diabetic rats, and both variables were corrected by PARP inhibitors. Retinal VEGF protein (ELISA, immunohistochemistry), but not mRNA (ribonuclease protection assay) abundance, was increased in diabetic rats, and this increase was corrected by both 3-aminobenzamide and 1,5-isoquinolinediol. PARP inhibitors did not affect retinal glucose, sorbitol pathway intermediates or lipid peroxidation in diabetic rats. Hypoxia caused a several-fold increase in both VEGF-mRNA and protein in retinal pigment epithelial cells. VEGF mRNA overexpression was only slighly blunted by PARP inhibitors whereas VEGF protein was corrected. In conclusion, PARP is involved in diabetes- and hypoxia-induced VEGF production at post-transcriptional level, downstream from the sorbitol pathway activation and oxidative stress. The results justify studies of PARP inhibitors in models of retinopathy of prematurity and diabetic retinopathy.
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PMID:Poly(ADP-ribose) polymerase inhibitors counteract diabetes- and hypoxia-induced retinal vascular endothelial growth factor overexpression. 1520 16

Poly(ADP-ribose) polymerase (PARP) inhibition has recently been identified as a novel approach to treatment of experimental peripheral diabetic neuropathy (PDN). However, long-term inhibition of PARP, an enzyme involved in DNA repair, can potentially result in premature aging, loss of genome stability, and other side effects. This study evaluated potential synergistic interactions between low doses of the potent and specific PARP inhibitor 1,5-isoquinolinediol (ISO) and one of two vasodilators, the ACE inhibitor lisinopril (LIS) and the beta2-adrenoceptor agonist salbutamol (SAL) in the model of early PDN. Control and streptozotocin (STZ)-induced diabetic rats were treated with either ISO plus LIS or ISO plus SAL for 2 weeks after an initial 2 weeks without treatment. ISO (intraperitoneally) and LIS and SAL (both in the drinking water) were used in subtherapeutic doses, resulting in a minor correction of diabetes-associated sciatic motor and hind-limb digital sensory nerve conduction deficits when administered as monotherapies. Both combination treatments corrected endoneurial blood flow and vascular conductance deficits in STZ-induced diabetic rats. ISO plus SAL corrected all other changes of PDN, i.e., motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV) deficits as well as thermal and mechanical hyperalgesia. With ISO plus LIS, no significant correction of MNCV was observed, and the effect on thermal hyperalgesia was quite modest. SNCV and mechanical hyperalgesia were corrected. In vitro studies in human endothelial and Schwann cells showed early accumulation of poly(ADP-ribosyl)ated proteins (Western blot analysis) in response to high glucose, thus suggesting the importance of PARP activation in human PDN. In conclusion, low-dose PARP inhibitor-containing combination therapies may constitute a new approach for treatment of PDN.
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PMID:Low-dose poly(ADP-ribose) polymerase inhibitor-containing combination therapies reverse early peripheral diabetic neuropathy. 1585 40

Poly(ADP-ribose) polymerase (PARP) activation is emerging as a fundamental mechanism in the pathogenesis of diabetes complications including diabetic neuropathy. This study evaluated the role of PARP in diabetic sensory neuropathy. The experiments were performed in control and streptozotocin-induced diabetic rats treated with or without the PARP inhibitor 1,5-isoquinolinediol (ISO; 3 mg x kg(-1) x day(-1) i.p.) for 2 weeks after 2 weeks without treatment. Diabetic rats developed thermal hyperalgesia (assessed by paw-withdrawal and tail-flick tests), mechanical hyperalgesia (von Frey anesthesiometer/rigid filaments and Randall-Sellito tests), tactile allodynia (flexible von Frey filaments), and increased flinching behavior in phases 1 and 2 of the 2% formalin pain test. They also had clearly manifest increase in nitrotyrosine and poly(ADP-ribose) immunoreactivities in the sciatic nerve and increased superoxide formation (hydroxyethidine method) and nitrotyrosine immunoreactivity in vasa nervorum. ISO treatment alleviated abnormal sensory responses, including thermal and mechanical hyperalgesia and tactile allodynia as well as exaggerated formalin flinching behavior in diabetic rats, without affecting the aforementioned variables in the control group. Poly(ADP-ribose) and, to a lesser extent, nitrotyrosine abundance in sciatic nerve, as well as superoxide and nitrotyrosine formation in vasa nervorum, were markedly reduced by ISO therapy. Apoptosis in dorsal root ganglion neurons (transferase-mediated dUTP nick-end labeling assay) was not detected in any of the groups. In conclusion, PARP activation contributes to early diabetic sensory neuropathy by mechanisms that may include oxidative stress but not neuronal apoptosis.
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PMID:Poly(ADP-ribose) polymerase inhibition alleviates experimental diabetic sensory neuropathy. 1673 31


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