Contribution of Reactive Oxygen Species to 3-Hydroxyglutarate Neurotoxicity in Primary Neuronal Cultures from Chick Embryo Telencephalons

Publisher Website
Google Scholar
Abstract
Glutaryl-CoA dehydrogenase deficiency is an autosomal recessively inherited neurometabolic disorder with a distinct neuropathology characterized by acute encephalopathic crises during a vulnerable period of brain development. 3-Hydroxyglutarate (3-OH-GA), which accumulates in affected patients, has been identified as an endogenous neurotoxin mediating excitotoxicity via N-methyl-d-aspartate receptors. As increased generation of reactive oxygen species (ROS) and nitric oxide (NO) plays an important role in excitotoxic neuronal damage, we investigated whether ROS and NO contribute to 3-OH-GA neurotoxicity. 3-OH-GA increased mitochondrial ROS generation in primary neuronal cultures from chick embryo telencephalons, which could be prevented by MK-801, confirming the central role of N-methyl-d-aspartate receptor stimulation in 3-OH-GA toxicity. ROS increase was reduced by α-tocopherol and—less effectively—by melatonin. α-Tocopherol revealed a wider time frame for neuroprotection than melatonin. Creatine also reduced neuronal damage and ROS formation but only if it was administered ≥6 h before 3-OH-GA. NO production revealed only a slight increase after 3-OH-GA incubation. NO synthase inhibitor Nω-nitro-l-arginine prevented NO increase but did not protect neurons against 3-OH-GA. The NO donor S-nitroso-N-acetylpenicillamine revealed no effect on 3-OH-GA toxicity at low concentrations (0.5–5 μM), whereas it potentiated neuronal damage at high concentrations (50–500 μM), suggesting that weak endogenous NO production elicited by 3-OH-GA did not affect neuronal viability. We conclude from our results that ROS generation contributes to 3-OH-GA neurotoxicity in vitro and that radical scavenging and stabilization of brain energy metabolism by creatine are hopeful new strategies in glutaryl-CoA dehydrogenase deficiency.