Poly ADP-ribose Synthase Research Articles

Inhibition of inducible nitric oxide synthase in vitro and in vivo by a water-soluble extract of Wendita calysina leaves

Wendita calysina is a Paraguayan herbaceous plant commonly known as burrito. Our previous study indicated that burrito leaves are a very good source of phenylpropanoid glycosides, principally verbascoside. From W. calysina leaves, a standardized, water-soluble extract (WSE) rich in phenylpropanoid glycosides has been developed on an industrial scale to be used as a food supplement, cosmetic, phytomedicine, and ingredient of different formulations. In this study, we investigated the effect of the W. calysina WSE both in vitro in murine macrophage cell line J774.A1 stimulated with lipopolysaccharide (LPS) and, in vivo in an animal model of acute inflammation, carrageenan-induced pleurisy. Here we report that W. calysina WSE (0.05, 0.1, and 0.5 mg/ml) inhibited inducible nitric oxide synthase (iNOS) expression and activity in LPS-stimulated J774.A1. In vivo experiments showed that injection of carrageenan (2%) into the pleural cavity of rats elicited an acute inflammatory response characterized by iNOS expression, intercellular adhesion molecule-1 (ICAM-1) up-regulation, nitrotyrosine and poly (ADP-ribose) synthase (PARS) formation, and lung tissue damage-all parameters significantly reduced by W. calysina WSE (500 mg/kg per os). These results report, for the first time, that a treatment with W. calysina WSE exerts anti-inflammatory effects both in vitro and in vivo.

Cigarette smoke condensate induces vascular oxidative stress and inflammation

Although the cardiovascular morbidity and mortality induced by cigarette smoking exceeds that attributable to lung cancer, the molecular basis of smoking-induced cardiovascular injury remains unclear. To test the hypothesis that water soluble components of the cigarette smoke condensate (CSC) elicit pro-inflammatory phenotypic changes in blood vessels we exposed isolated carotid arteries and aortas of male Wistar rats to CSC (0 to 40 μg/mL, for 6 h). Lucigenin chemiluminescence measurements showed that CSC significantly increased vascular O2.- production (0, 0.4, 4, 40 μg/mL: 100±12%, 126±18%, 167±26%, 199±29%, respectively). QRT-PCR analysis showed that mRNA expression of the pro-inflammatory cytokines IL-1â, IL-6 and TNFa (4 μg/mL: by 44±18%, 43±16% and 32±11%, respectively). Inhibition of poly-(ADP)ribose-synthase (PARS) with 3-aminobenzamide (10–3 mol/L) prevented the up-regulation of inflammatory cytokines by CSC. Expression of iNOS and that of ICAM-1 was unaffected by CSC under these experimental conditions. Thus, we propose that water soluble components of cigarette smoke, which are likely to be present in the bloodstream, can elicit oxidative stress and pro-atherogenic vascular phenotypic changes. Our data warrant further studies on the role of PARS inhibitors in pharmacological vasculoprotection in smokers. (Grant support: American Federation for Aging Research, AHAF H2004-024; Philip Morris USA).

Nitric oxide reverses endotoxin-induced inflammatory hyperalgesia via inhibition of prostacyclin production in mice

We examined whether nitric oxide (NO), derived from constitutive NO synthase (NOS) and/or inducible NOS (iNOS), could contribute to endotoxin-induced inflammatory hyperalgesia via interacting with nuclear factor-κB (NF-κB), inducible cyclooxygenase (COX-2) and/or polyADP-ribose synthase (PARS). Injection of endotoxin (10 mg kg −1, i.p.) to mice elicited hyperalgesia, determined by hot plate test, which is prevented by NO precursor ( l-arginine), cNOS/iNOS inhibitor ( N G-nitro- l-arginine methyl ester; l-NAME), NF-κB inhibitor ( N-acetylserotonin), COX inhibitor (indomethacin), COX-2 inhibitor (DFU) and PARS inhibitor (3-aminobenzamide). Endotoxin caused a decrease in serum nitrite levels prevented by N-acetylserotonin, l-arginine, indomethacin, DFU or 3-aminobenzamide. Endotoxin increased serum 6-keto-PGF 1α levels diminished by l-arginine or aminoguanidine (iNOS inhibitor). l-Arginine, l-NAME, aminoguanidine, DFU or 3-aminobenzamide prevented endotoxin-induced decrease in heart, lungs, kidneys and brain nitrite and malonedialdehyde levels and myeloperoxidase activity. In conclusion, NO reverses endotoxin-induced inflammatory hyperalgesia via inhibition of prostacyclin production, and also contributes to the analgesic effect of NF-κB, COX or PARS inhibitors.

Poly-ADP-ribose syhthase inhibition reduces mesenteric injury after cardiopulmonary bypass

Objectives: Mesenteric dysfunction is a rare but severe complication after cardiac surgery, which may be related to free radical production and subsequent activation of poly-ADP-ribose synthase (PARS). We investigated the effects of PARS-inhibition on intestinal injury in a canine model of cardiopulmonary bypass (CPB).

Inhibition of poly-ADP ribose synthase (PARS) increases cardiac myocyte survival during acute cardiac allograft rejection in rats

Death of cardiomyocytes by apoptosis and by necrosis is a hallmark of acute cardiac allograft rejection. Studies of cardiac myoblasts and cardiac myocytes in culture indicated that activation of poly ADP ribose synthase (PARS) by agonists such as NO, peroxynitrite and TNFalpha contribute to both forms of cardiac muscle cell death. To investigate the role of PARS activation in acute allograft rejection Lewis-Wistar-Furth heterotopic abdominal heart transplantation was performed in rats. In animals treated with the PARS inhibitor 5-aminoisoquinolinone (5AIQ) (3 mg/kg i.p. bid) cardiac allograft survival was prolonged from 6 ± 2 to 10 ± 1.7 days (n=6, n=8 diff p<0.02). At day 5 following transplantation PARS mRNA, protein and poly ADP ribose protein were increased in the allografts of both groups. Myocyte damage determined by the TUNEL technique and immunoperoxidase staining for soluble fibronectin was reduced by 66% from 16.7 to 5.7 damaged myocytes per mm2 myocardium in vehicle vs. 5AIQ treated allografts. Myocardial inflammation was also reduced by 49% for ED1+ macrophages, 34% for CD3+ lymphocytes and 51% for NOS-2+ inflammatory cells.

Protective effects of poly (adp-ribose) synthase inhibitors on digoxin-induced cardiotoxicity in guinea-pig isolated hearts

Reactive oxygen species, generated and released during digoxin-induced cardiotoxicity, can produce an activation of poly (ADP-ribose) synthase (PARS). Our objective was to examine the effects of PARS inhibitors, 3-aminobenzamide (3-AB ) and nicotinamide, on digoxin-induced arrhythmias in guinea-pig isolated hearts. 3-AB (0.1–0.3 mM) and nicotinamide (0.3 mM) were added to the perfusion solution starting 10 min before digoxin infusion (8 μg ml −1min −1reaching the heart) and maintained throughout the experiments. Electrocardiograms and coronary perfusion pressure were recorded continuously, and digoxin-induced arrhythmias were determined. Nicotinamide markedly inhibited ventricular tachycardia (VT) incidence (from 100%, n= 7, to 29%, n= 7), and abolished ventricular fibrillation (VF) incidence. 3-AB (0.1 mM, n= 9) significantly decreased VT incidence from 100% ( n= 7) to 22% ( n= 9) and VF incidence from 86% ( n= 7) to 11% ( n= 9). Both nicotinamide and 3-AB (0.1 mM) markedly decreased number of ventricular ectopic beats (VEBs) and arrhythmia score. 3-AB at 0.3 mM ( n= 8) appeared to decrease the VT (to 63%) and VF incidence (to 38%), but these reductions did not reach statistically significance levels. Moreover, 3-AB at high concentration (0.3 mM) did not significantly modify the number of VEBs and arrhythmia score. There were no significant changes in coronary perfusion pressure, heart rate or pressure rate index measured at certain time points throughout the experiment in all groups. Our results suggest that PARS activation plays a role in the digitalis-induced cardiotoxicity in guinea-pig isolated hearts.

The protective effect of niacinamide on ischemia-reperfusion-induced liver injury.

Reperfusion of ischemic liver results in the generation of oxygen radicals, nitric oxide (NO) and their reaction product peroxynitrite, all of which may cause strand breaks in DNA, which activate the nuclear enzyme poly(ADP ribose)synthase (PARS). This results in rapid depletion of intracellular nicotinamide adenine dinucleotide and adenosine 5'-triphosphate (ATP) and eventually induces irreversible cytotoxicity. In this study, we demonstrated that niacinamide, a PARS inhibitor, attenuated ischemia/reperfusion (I/R)-induced liver injury. Ischemia was induced by clamping the common hepatic artery and portal vein of rats for 40 min. Thereafter, flow was restored and the liver was reperfused for 90 min. Blood samples collected prior to I and after R were analyzed for methyl guanidine (MG), NO, tumor necrosis factor (TNF-alpha) and ATP. Blood levels of aspartate transferase (AST), alanine transferase (ALT) and lactate dehydrogenase (LDH) which served as indexes of liver injury were measured. This protocol resulted in elevation of the blood NO level (p < 0.01). Inflammation was apparent, as TNF-alpha and MG levels were significantly increased (p < 0.05 and p < 0.001). AST, ALT and LDH were elevated 4- to 5-fold (p < 0.001), while ATP was significantly diminished (p < 0.01). After administration of niacinamide (10 mM), liver injury was significantly attenuated, while blood ATP content was reversed. In addition, MG, TNF-alpha and NO release was attenuated. These results indicate that niacinamide, presumably by acting with multiple functions, exerts potent anti-inflammatory effects in I/R-induced liver injury.

Mort neuronale : rôle potentiel d’une enzyme nucléaire, la poly(ADP-ribose) polymérase

Poly(ADP-ribose) polymerase (PARP, EC 2.4.2.30) is known as a nuclear enzyme that is activated by DNA strand breaks to participate in DNA repair. It is also called poly(ADP-ribose) synthase (PARS) or poly(ADP-ribose) transferase (PADRT). In physiological conditions, PARP plays an important role in maintaining genomic stability. However, for several pathological situations, which include massive DNA injury (brain ischemia for example), excessive activation of PARP can deplete stores of nicotinamide adenine dinucleotide (NAD+), the PARP substrate, which, with the subsequent ATP depletion, leads to cell death. PARP activation appears to play a major role in neuronal death induced by cerebral ischemia, traumatic brain injury, Parkinson disease and other pathologies. PARP inhibitors (3-aminobenzamide and other compounds) and PARP gene deletion induced dramatic neuroprotection in experimental animals (rats, mice). Accordingly, these data suggest that PARP inhibitors could provide a novel therapeutic approach in a wide range of neurodegenerative disorders including cerebral ischemia and traumatic brain injury.

The Protective Effect of Niacinamide on Ischemia-Reperfusion-Induced Liver Injury

Reperfusion of ischemic liver results in the generation of oxygen radicals, nitric oxide (NO) and their reaction product peroxynitrite, all of which may cause strand breaks in DNA, which activate the nuclear enzyme poly(ADP ribose)synthase (PARS). This results in rapid depletion of intracellular nicotinamide adenine dinucleotide and adenosine 5′-triphosphate (ATP) and eventually induces irreversible cytotoxicity. In this study, we demonstrated that niacinamide, a PARS inhibitor, attenuated ischemia/reperfusion (I/R)-induced liver injury. Ischemia was induced by clamping the common hepatic artery and portal vein of rats for 40 min. Thereafter, flow was restored and the liver was reperfused for 90 min. Blood samples collected prior to I and after R were analyzed for methyl guanidine (MG), NO, tumor necrosis factor (TNF-α) and ATP. Blood levels of aspartate transferase (AST), alanine transferase (ALT) and lactate dehydrogenase (LDH) which served as indexes of liver injury were measured. This protocol resulted in elevation of the blood NO level (p < 0.01). Inflammation was apparent, as TNF-α and MG levels were significantly increased (p < 0.05 and p < 0.001). AST, ALT and LDH were elevated 4- to 5-fold (p < 0.001), while ATP was significantly diminished (p < 0.01). After administration of niacinamide (10 mM), liver injury was significantly attenuated, while blood ATP content was reversed. In addition, MG, TNF-α and NO release was attenuated. These results indicate that niacinamide, presumably by acting with multiple functions, exerts potent anti-inflammatory effects in I/R-induced liver injury.

BCL-2 protects peroxynitrite-treated thymocytes from poly(ADP-ribose) synthase (PARS)-independent apoptotic but not from PARS-mediated necrotic cell death

In thymocytes, peroxynitrite induces poly(ADP-ribose) synthetase (PARS) activation, which results in necrotic cell death. In the absence of PARS, however, peroxynitrite-treated thymocytes die by apoptosis. Because Bcl-2 has been reported to inhibit not only apoptotic but also some forms of necrotic cell death, here we have investigated how Bcl-2 regulates the peroxynitrite-induced apoptotic and necrotic cell death. We have found that Bcl-2 did not provide protection against peroxynitrite-induced necrotic death, as characterized by propidium iodide uptake, mitochondrial membrane potential decrease, secondary superoxide production, and cardiolipin loss. In the presence of a PARS inhibitor, peroxynitrite-treated thymocytes from Bcl-2 transgenic mice showed no caspase activation or DNA fragmentation and displayed smaller mitochondrial membrane potential decrease. These data show that Bcl-2 protects thymocytes from peroxynitrite-induced apoptosis at a step proximal to mitochondrial alterations but fails to prevent PARS-mediated necrotic cell death. Activation of tissue transglutaminase (tTG) occurs in various forms of apoptosis. Peroxynitrite did not induce transglutaminase activity in thymocytes and did not have a direct inhibitory effect on the purified tTG. Basal tTG was not different in Bcl-2 transgenic and wild type cells.

Poly(ADP‐Ribose) Synthase Inhibition Reduces Ischemic Injury and Inflammation in Neonatal Rat Brain

Poly(ADP-ribose) synthase (PARS), an abundant nuclear protein, has been described as an important candidate for mediation of neurotoxicity by nitric oxide. However, in cerebral ischemia, excessive PARS activation may lead to energy depletion and exacerbation of neuronal damage. We examined the effect of inhibiting PARS on the (a) degree of cerebral injury, (b) process of inflammatory responses, and (c) functional outcomes in a neonatal rat model of focal ischemia. We demonstrate that administration of 3-aminobenzamide, a PARS inhibitor, leads to a significant reduction of infarct volume: 63 +/- 2 (untreated) versus 28 +/- 4 mm(3) (treated). The neuroprotective effects currently observed 48 h postischemia hold up at 7 and 17 days of survival time and attenuate neurological dysfunction. Inhibition of PARS activity, demonstrated by a reduction in poly(ADP-ribose) polymer formation, also reduces neutrophil recruitment and levels of nitrotyrosine, an indicator of peroxynitrite generation. Taken together, our results demonstrate that PARS inhibition reduces ischemic damage and local inflammation associated with reperfusion and may be of interest for the treatment of neonatal stroke.

Inhibition of PARS attenuates endotoxin-induced dysfunction of pulmonary vasorelaxation.

Endotoxin (Etx) causes excessive activation of the nuclear repair enzyme poly(ADP-ribose) synthase (PARS), which depletes cellular energy stores and leads to vascular dysfunction. We hypothesized that PARS inhibition would attenuate injury to mechanisms of pulmonary vasorelaxation in acute lung injury. The purpose of this study was to determine the effect of in vivo PARS inhibition on Etx-induced dysfunction of pulmonary vasorelaxation. Rats received intraperitoneal saline or Etx (Salmonella typhimurium; 20 mg/kg) and one of the PARS inhibitors, 3-aminobenzamide (3-AB; 10 mg/kg) or nicotinamide (Nic; 200 mg/kg), 90 min later. After 6 h, concentration-response curves were determined in isolated pulmonary arterial rings. Etx impaired endothelium-dependent (response to ACh and calcium ionophore) and -independent (sodium nitroprusside) cGMP-mediated vasorelaxation. 3-AB and Nic attenuated Etx-induced impairment of endothelium-dependent and -independent pulmonary vasorelaxation. 3-AB and Nic had no effect on Etx-induced increases in lung myeloperoxidase activity and edema. Lung ATP decreased after Etx but was maintained by 3-AB and Nic. Pulmonary arterial PARS activity increased fivefold after Etx, which 3-AB and Nic prevented. The beneficial effects were not observed with benzoic acid, a structural analog of 3-AB that does not inhibit PARS. Our results suggest that PARS inhibition with 3-AB or Nic improves pulmonary vasorelaxation and preserves lung ATP levels in acute lung injury.