title: Prefibrillar amyloid protein aggregates share common features of cytotoxicity.
abstract: The intracellular free Ca(2+) concentration and redox status of murine fibroblasts exposed to prefibrillar aggregates of the HypF N-terminal domain have been investigated in vitro and in vivo using a range of fluorescent probes. Aggregate entrance into the cytoplasm is followed by an early rise of reactive oxygen species and free Ca(2+) levels and eventually by cell death. Such changes correlate directly with the viability of the cells and are not observed when cell are cultured in the presence of reducing agents or in Ca(2+)-free media. In addition, moderate cell stress following exposure to the aggregates was found to be fully reversible. The results show that the cytotoxicity of prefibrillar aggregates of HypF-N, a protein not associated with clinical disease, has the same fundamental origin as that produced by similar types of aggregates of proteins linked with specific amyloidoses. These findings suggest that misfolded proteinaceous aggregates stimulate generic cellular responses as a result of the exposure of regions of the structure (such as hydrophobic residues and the polypeptide main chain) that are buried in the normally folded proteins. They also support the idea that a higher number of degenerative pathologies than previously known might be considered as protein deposition diseases.
authors.affiliation: Department of Biochemical Sciences, University of Florence, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Bucciantini
authors.forename: Giulia
authors.initials: G
authors.lastname: Calloni
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Chiti
authors.forename: Lucia
authors.initials: L
authors.lastname: Formigli
authors.forename: Daniele
authors.initials: D
authors.lastname: Nosi
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Dobson
authors.forename: Massimo
authors.initials: M
authors.lastname: Stefani
mesh_terms: D000682:Amyloid / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity*; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D046911:Macromolecular Substances; D051379:Mice; D018613:Microscopy, Confocal; D041681:NIH 3T3 Cells; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000682:Amyloid; D001426:Bacterial Proteins; C108878:HypF protein, Bacteria; D046911:Macromolecular Substances; D017382:Reactive Oxygen Species; D002118:Calcium