Calpain inhibitors prevent nitric oxidetriggered excitotoxic apoptosis
2001, Volbracht, Christiane, Fava, Eugenio, Leist, Marcel, Nicotera, Pierluigi
The pathogenesis of some neurodegenerative disorders has been linked to excitotoxicity, excess generation of nitric oxide (NO) and apoptosis. Here, we used a model of NO-triggered neuronal apoptosis that was strictly dependent on autocrine NMDA receptor (NMDA-R) activation and intracellular Ca2 increase. We investigated the efficiency and potentially beneficial effects of calpain inhibition. Three calpain inhibitors that prevented intracellular fodrin proteolysis also blocked apoptotic features such as decrease in mitochondrial membrane potential, chromatin breakdown, and subsequent death of cerebellar granule neurons exposed to NO donors (S-nitroso- L-glutathione, S-nitroso-N-acetyl D,L-penicillamine, and diethylamino- diazenolate-2-oxide). Since inhibitors did not interfere with NMDA-R activation, we suggest that block of calpains blunts NO-triggered neuronal apoptosis by stopping the cascade downstream of primary autocrine excitotoxic events.
Neuronal death in nigral grafts in the absence of poly (ADP-ribose) polymerase activation
1999, Schierle, Gabriele S. Kaminski, Hansson, Oskar, Ferrando-May, Elisa, Nicotera, Pierluigi, Brundin, Patrik, Leist, Marcel
The exact causes of the extensive cell death in nigral transplants are still unknown. Since poly-(ADP-ribose) polymerase (PARP) overactivation has been implicated in neuronal death, we examined the effects of PARP on the survival of nigral grafts by using donor tissue from PARP knock-out or wild-type mice. Eight hours after preparation of the nigral cell suspension, cell damage was quantified by measurement of lactate dehydrogenase release, DNA fragmentation and caspase activation. At this stage, PARP deletion had no protective effect. Moreover, neither the survival of transplanted dopaminergic neurons, nor the functional recovery of hemiparkinsonian graft recipients were improved by the absence of PARP. We conclude that cell death in embryonic nigral grafts is not affected by the absence of PARP activation.