Counterman AE, D'Onofrio TG, Andrews AM, Weiss PS. A physical model of axonal damage due to oxidative stress.
Proc Natl Acad Sci U S A 2006;
103:5262-6. [PMID:
16569704 PMCID:
PMC1459344 DOI:
10.1073/pnas.0504134103]
[Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Oxidative damage is implicated in the pathogenesis of neurodegenerative disorders, including Alzheimer's, Parkinson's, and Huntington's diseases, and in normal aging. Here, we model oxidative stress in neurons using photogenerated radicals in a simplified membrane-encapsulated microtubule system. Using fluorescence and differential interference contrast microscopies, we monitor photochemically induced microtubule breakdown on the supported region of membrane in encapsulating synthetic liposomes as a function of lipid composition and environment. Degradation of vesicle-encapsulated microtubules is caused by attack from free radicals formed upon UV excitation of the lipid-soluble fluorescent probe, 6-(9-anthroyloxy)stearic acid. Probe concentration was typically limited to a regime in which microtubule degradation was slow, and microtubule degradation was monitored by changes in the observed protrusion of the membrane surface. The kinetics of microtubule degradation are influenced by lipid saturation level, fluorescent probe concentration, and the presence of free-radical scavengers. This system is sufficient to reproduce some degenerative morphologies found in vivo.
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