Investigators at the Burnham Institute for Medical Research (Burnham) have demonstrated that attacks on the mitochondrial protein Drp1 by the free radical nitric oxide-which causes a chemical reaction called S-nitrosylation-mediates neurodegeneration associated with Alzheimer's disease.
Prior to this study, the mechanism by which beta-amyloid protein caused synaptic damage to neurons in Alzheimer's disease was unknown. These findings suggest that preventing S-nitrosylation of Drp1 may reduce or even prevent neurodegeneration in Alzheimer's patients. The paper was published in the April 3 issue of the journal Science .
The team of scientists, led by neuroscientist and clinical neurologist Stuart A. Lipton, M.D., Ph.D., director of the Del E. Webb Center for Neuroscience, Aging and Stem Cell Research, showed that S-nitrosylated Drp1 (SNO-Drp1) facilitates mitochondrial fragmentation, damaging regions of nerve cell communication called synapses. Mitochondria are the energy storehouses of the cell, and their compromise by excessive fragmentation causes synaptic injury and eventual nerve cell death. Synapses are critical for learning and memory and their impairment leads to the dementia seen in Alzheimer's patients.
"We now have a better understanding of the mechanism by which beta-amyloid protein causes neurodegeneration in Alzheimer's disease," said Dr. Lipton. "We found that beta-amyloid can generate nitric oxide that reacts with Drp1. By identifying Drp1 as the protein responsible for synaptic injury, we now have a new target for developing drugs that may slow or stop the progression of Alzheimer's."