gpi-6150 and Disease-Models--Animal

Severe hypoglycemia causes neuronal death and cognitive impairment. Evidence suggests that hypoglycemic neuronal death involves excitotoxicity and DNA damage. Poly(ADP-ribose) polymerase-1 (PARP-1) normally functions in DNA repair, but promotes cell death when extensively activated by DNA damage. Cortical neuron cultures were subjected to glucose deprivation to assess the role of PARP-1 in hypoglycemic neuronal death. PARP-1-/- neurons and wild-type, PARP-1+/+ neurons treated with the PARP inhibitor 3,4-dihydro-5-[4-(1-piperidinyl)butoxy]-1(2H)-isoquinolinone both showed increased resistance to glucose deprivation. A rat model of insulin-induced hypoglycemia was used to assess the therapeutic potential of PARP inhibitors after hypoglycemia. Rats subjected to severe hypoglycemia (30 min EEG isoelectricity) accumulated both nitrotyrosine and the PARP-1 product, poly(ADP-ribose), in vulnerable neurons. Treatment with PARP inhibitors immediately after hypoglycemia blocked production of poly(ADP-ribose) and reduced neuronal death by >80% in most brain regions examined. Increased neuronal survival was also achieved when PARP inhibitors were administered up to 2 hr after blood glucose correction. Behavioral and histological assessments performed 6 weeks after hypoglycemia confirmed a sustained salutary effect of PARP inhibition. These results suggest that PARP-1 activation is a major factor mediating hypoglycemic neuronal death and that PARP-1 inhibitors can rescue neurons that would otherwise die after severe hypoglycemia.

Topics: Animals; Astrocytes; Behavior, Animal; Benzamides; Benzopyrans; Cell Death; Cells, Cultured; Cognition Disorders; Disease Models, Animal; Drug Administration Schedule; Enzyme Inhibitors; Hypoglycemia; Isoquinolines; Male; Maze Learning; Mice; Mice, Knockout; Neurons; Poly(ADP-ribose) Polymerase Inhibitors; Rats; Rats, Sprague-Dawley; Receptors, Glutamate; Time Factors; Treatment Outcome; Tyrosine

Poly (ADP-ribose) polymerase, a nuclear enzyme activated by DNA strand breaks, has been show to play an important role in the pathogenesis of inflammation. Here, we investigate the effects of GPI 6150 (1,11b-dihydro-[2H]benzopyrano [4,3,2-de]isoquinolin-3-one), a new poly (ADP-ribose) polymerase inhibitor, in animal models of acute and chronic inflammation (carrageenan-induced paw edema, adjuvant-induced arthritis and zymosan-induced multiple organ failure) where oxygen radicals, nitric oxide and peroxynitrite are known to play a crucial role in the inflammatory process. The results show that the poly (ADP-ribose) polymerase inhibitor GPI 6150 inhibits the inflammatory response (paw swelling, and organ injury). The present results demonstrate that inhibition of poly (ADP-ribose) polymerase by GPI 6150 exerts potent anti-inflammatory effects. Part of these anti-inflammatory effects may be related to a reduction of neutrophil recruitment into the inflammatory site.

Topics: Animals; Anti-Inflammatory Agents; Arthritis, Experimental; Benzopyrans; Carrageenan; Disease Models, Animal; Dose-Response Relationship, Drug; Edema; Enzyme Inhibitors; Hindlimb; Inflammation; Isoquinolines; Liver; Lung; Male; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Rats; Rats, Long-Evans; Survival Rate; Zymosan