TY - JOUR T1 - Novel Isoquinolinone-Derived Inhibitors of Poly(ADP-ribose) Polymerase-1: Pharmacological Characterization and Neuroprotective Effects in an in Vitro Model of Cerebral Ischemia JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 943 LP - 949 DO - 10.1124/jpet.103.048934 VL - 305 IS - 3 AU - Alberto Chiarugi AU - Elena Meli AU - Maura Calvani AU - Roberta Picca AU - Roberto Baronti AU - Emidio Camaioni AU - Gabriele Costantino AU - Maura Marinozzi AU - Domenico E. Pellegrini-Giampietro AU - Roberto Pellicciari AU - Flavio Moroni Y1 - 2003/06/01 UR - http://jpet.aspetjournals.org/content/305/3/943.abstract N2 - Excessive activation of poly(ADP-ribose) polymerase-1 (PARP-1), a nuclear enzyme catalyzing the transfer of ADP-ribose units from NAD to acceptor proteins, induces cellular energy failure by NAD and ATP depletion and has been proposed to play a causative role in a number of pathological conditions, including ischemia/reperfusion injury. In this study, we used an in vitro enzyme activity assay to characterize a series of newly synthesized isoquinolinone derivatives as potential PARP-1 inhibitors. Several compounds displayed powerful inhibitory activity: thieno[2,3-c]isoquinolin-5-one (TIQ-A) displayed a submicromolar IC50 of 0.45 ± 0.1 μM, whereas the 5-hydroxy and 5-methoxy TIQ-A derivatives had IC50 values of 0.39 ± 0.19 and 0.21 ± 0.12 μM, respectively. We then examined the neuroprotective effects of the newly characterized compounds in cultured mouse cortical cells exposed to 60 min of oxygen and glucose deprivation (OGD). When PARP-1 inhibitors were present in the incubation medium during OGD and the subsequent 24-h recovery period, they significantly attenuated neuronal injury. TIQ-A provided neuroprotection even when added to the culture 30 min after OGD and was able to reduce the early activation of PARP induced by OGD as detected by flow cytometry. When the IC50 values observed in the PARP-1 activity assay for selected compounds were compared with their IC50 values for the neuroprotective activity, a significant correlation (r = 0.93, P < 0.01) was observed. Our results suggest that TIQ-A and its derivatives are a new class of neuroprotectants that may be helpful in studies aimed at understanding the involvement of PARP-1 in physiology and pathology. The American Society for Pharmacology and Experimental Therapeutics ER -