Mitochondrial dysfunction and oxidative stress in seizure-induced neuronal cell death.

Abstract

Epilepsy is considered one of the most common neurological disorders worldwide. The burst firing associated with prolonged epileptic discharges could lead to a large number of changes and cascades of events at the cellular level. From its role as the cellular powerhouse, the mitochondrion is emerging as a key participant in cell death because of its association with an ever-growing list of apoptosis-related proteins. Prolonged seizures may result in the mitochondrial dysfunction and increased production of reactive oxygen species and nitric oxide (NO) precede neuronal cell death and cause subsequent epileptogenesis. Emerging evidences also showed that intrinsic mitochondrial apoptotic pathway may contribute to the neuropathology of human epilepsy, particularly in the hippocampus. Subsequent laboratory studies in the animal model of status epilepticus provide credence to the notion that activation of nuclear factor-κB upregulates NO synthase (NOS) II gene expression with temporal correlation of NOS II derived NO-, superoxide anion- and peroxynitrite-dependent reduction in mitochondrial Complex I activity, leading to apoptotic neuronal cell death in the hippocampus. These results will broaden our understanding on the intimate link between mitochondrial function, oxidative stress and mitochondria-dependent apoptotic signaling triggered by epileptic seizures. It will open a new vista in the development of more effective neuroprotective strategies against seizure-induced brain damage by modification of bioenergetic failure in the mitochondria and in the design of novel treatment perspectives for therapy-resistant forms of epilepsy.