title: Development of a novel diffusion-based method to estimate the size of the aggregated Abeta species responsible for neurotoxicity.
abstract: beta-Amyloid peptide (Abeta) is the primary protein component of senile plaques in Alzheimer's disease and is believed to be responsible for the neurodegeneration associated with the disease. Abeta is toxic only when aggregated, however, the size and structure of the aggregated species associated with toxicity is unknown. In the present study, we developed a diffusion-based method to simultaneously separate and detect the biological activity of toxic Abeta oligomers and used the method to examine the relationship between size of aggregated protein and toxicity to SH-SY5Y cells. From these measurements, the effective diffusivity and hydrodynamic radius of the toxic oligomeric species of Abeta could be determined. A sensitivity analysis was performed to examine the effects of model assumptions used in data analysis on the effective diffusivity calculated. The method provides a new estimate of the size of small toxic Abeta species associated with fibril formation. This work contributes to our understanding of the relationship between Abeta structure and toxicity and with further refinements may aid in our ability to design agents which alter the Abeta aggregation/dissociation processes associated with neurotoxicity.
authors.affiliation: Department of Chemical Engineering, Texas A&M University, TAMU 3122, College Station, Texas 77843-3122, USA.
authors.forename: Steven S-S
authors.initials: SS
authors.lastname: Wang
authors.forename: Alejandro
authors.initials: A
authors.lastname: Becerra-Arteaga
authors.forename: Theresa A
authors.initials: TA
authors.lastname: Good
mesh_terms: D000544:Alzheimer Disease / Q000209:etiology / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity*; D002470:Cell Survival; D004058:Diffusion; D004867:Equipment Design; D005434:Flow Cytometry / Q000295:instrumentation / Q000379:methods; D006801:Humans; D046911:Macromolecular Substances; D008954:Models, Biological; D008970:Molecular Weight; D009447:Neuroblastoma / Q000378:metabolism / Q000503:physiopathology; D025941:Protein Interaction Mapping; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012685:Sepharose; D013045:Species Specificity; D018675:Toxicity Tests / Q000295:instrumentation / Q000379:methods; D014407:Tumor Cells, Cultured
chemical_list: D016229:Amyloid beta-Peptides; D046911:Macromolecular Substances; D012685:Sepharose