Nitric Oxide Links Mitochondrial Fission to Alzheimer’s Disease

Mitochondrial dysfunction is a hallmark of beta-amyloid (Abeta)-induced neuronal injury in the pathogenesis of Alzheimer's disease. Neurotoxic Abeta peptide, thought to be a key mediator of Alzheimer's disease, may be imported into human brain mitochondria, where it inhibits key enzymes of respiratory metabolism. Nitric oxide (NO) produced in response to Abeta induces S-nitrosylation of the mitochondrial division protein, dynamin-related protein 1 (Drp-1), which leads to excessive mitochondrial fission, synaptic loss, and neuronal damage. Furthermore, brains of patients with Alzheimer's disease contain high amounts of S-nitrosylated Drp-1. Abeta-dependent mitochondrial fragmentation likely enhances the decline in bioenergetic capacity of damaged mitochondria and therefore contributes to neuronal injury and pathogenesis of Alzheimer's disease.