Inhibition of the activity of poly(ADP ribose) synthetase reduces ischemia–reperfusion injury in the heart and skeletal muscle

Abstract

Reperfusion of the ischemic myocardium results in the generation of oxygen-derived free radicals, NO, and presumably peroxynitrite. These, in turn, may cause strand breaks in DNA, which activate the nuclear enzyme poly(ADP ribose) synthetase (PARS). This results in a rapid depletion of intracellular NAD and ATP. When this reaction is excessive, there is ultimately cell death. Here we demonstrate that 3-aminobenzamide (and several other, chemically distinct, inhibitors of PARS activity) reduces the infarct size caused by ischemia and reperfusion of the heart or skeletal muscle of the rabbit. Inhibition of PARS activity also attenuates the myocardial dysfunction caused by global ischemia and reperfusion in the isolated, perfused heart of the rabbit. In skeletal muscle, inhibition of the activity of neuronal NO synthase reduces infarct size, indicating that the formation of NO contributes to the activation of PARS there. There is no significant neuronal NO synthase activity in the heart, and hence NO synthase inhibitors did not reduce myocardial infarct size. Thus, activation of PARS contributes to the cell death caused by ischemia-reperfusion, and PARS inhibitors may constitute a novel therapy for ischemia-reperfusion injury.Poly(ADP ribose) synthetase (PARS; EC 2.4.2.30) is a chromatin-bound enzyme, which plays a physiological role in the repair of strand breaks in DNA (1). PARS is located in the nuclei of cells of various tissues, including the heart and skeletal muscle (2). When activated by strand breaks in DNA, PARS catalyzes the transfer of ADP ribose moieties from NAD with the concomitant formation of nicotinamide. This results in a substantial depletion of NAD. Nicotinamide, which inhibits PARS activity by negative feedback, can be recycled to NAD in a reaction that consumes ATP. As NAD is essential to mitochondrial electron transport, depletion of NAD rapidly leads to a fall in ATP, and ultimately cell death (3-5). Radicals including superoxide anions, hydrogen peroxide or hydroxyl radicals (3-5), and NO or peroxynitrite (6-8) cause the breakage of DNA strands and activation of PARS. Inhibitors of PARS activity attenuate the fall in NAD and ATP and improve survival of cultured cells (e.g., fibroblasts, endothelial cells, and smooth muscle cells) exposed to oxygen-derived free radicals (3-5, 9), NO (6-8), or peroxynitrite (8). The formation of radicals contributes to the ''reperfusion injury'' of previously ischemic organs, including the heart (10) and the skeletal muscle (11). Here we demonstrate that several inhibitors of PARS activity reduce the infarct size caused by ischemia-reperfusion of the heart and skeletal muscle. MATERIALS AND METHODS Determination of Myocardial Infarct Size (in Vivo).Male New Zealand white rabbits were premedicated [Hypnorm (Janssen, Saunderton, U.K.), 0.1 ml⅐kg Ϫ1 i.m.; containing 0.315 mg⅐ml Ϫ1 fentanyl citrate and 10 mg⅐mlϪ1 fluanisone] and anesthetized (pentobarbitone, 20 mg⅐kg Ϫ1 i.v.). Following tracheotomy and ventilation (36-40 strokes⅐min Ϫ1 , tidal volume: 18...

Cerebral Endothelial Cell Apoptosis after Ischemia—Reperfusion: Role of PARP Activation and AIF Translocation

“…In our HBMEC model of HX/RO that results in a 30% to 40% loss of cell viability, treatment with 3-AB and 4-AN, two mechanistically distinct PARP-1 inhibitors (Banasik et al, 1992;Schlicker et al, 1999;Thiemermann et al, 1997), during HX/RO dosedependently blocked AIF translocation and reduced apoptotic cell death, supporting the concept that early PARP-1 activation is an upstream trigger of mitochondrial AIF release in cerebral endothelium.…”

Design and synthesis of a new steroid-macrocyclic derivative with biological activity

“…All these data suggest that the molecular mechanism involved in the activity of the compound 11 is via androgen receptor. This phenomenon is similar to the activity exerted by other drugs on left ventricular pressure [41], however via a different molecular mechanism, which may contribute to decreased cell death caused by heart failure. There are some reports which indicate that several macrocyclic derivatives have biological activity and can modulate the activity exerted by the androgen receptor [41,42].…”

“…This phenomenon is similar to the activity exerted by other drugs on left ventricular pressure [41], however via a different molecular mechanism, which may contribute to decreased cell death caused by heart failure. There are some reports which indicate that several macrocyclic derivatives have biological activity and can modulate the activity exerted by the androgen receptor [41,42]. In order to evaluate this hypothesis, several studies have been conducted to predict the interaction of Table 4 Interaction of amino acid fragments with testosterone Hydrogen bonds Polar Hydrophobic Cation-pi Other macrocyclic with the androgen receptor using theoretical models [13][14][15][16].…”

Increased expression and activation of poly(ADP-ribose) polymerase (PARP) contribute to retinal ganglion cell death following rat optic nerve transection

“…Excessive activation of poly(ADP-ribose) polymerase has been implicated to mediate cell death in different models of ischemia-reperfusion injury 10,40,42 as well as streptozotocininduced diabetes, 32 glutamate-induced neurotoxicity 5,49 and Alzheimer's disease. 27 The common feature in the pathogen- Figure 3 Poly(ADP-ribose) polymer immunohistochemistry on retinal sections to monitor PARP activation after ON transection with or without 3-ABA treatment.…”