Selenium-enhanced electron microscopic imaging of different aggregate forms of a segment of the amyloid β peptide in cells.
The aggregation of misfolded proteins is a common feature underlying a wide range of age-related degenerative disorders, including Alzheimer's and Parkinson's diseases. A key aspect of understanding the molecular origins of these conditions is to define the manner in which specific types of protein aggregates influence disease pathogenesis through their interactions with cells. We demonstrate how selenium-enhanced electron microscopy (SE-EM), combined with tomographic reconstruction methods, can be used to image, here at a resolution of 5-10 nm, the interaction with human macrophage cells of amyloid aggregates formed from Aβ(25-36), a fragment of the Aβ peptide whose self-assembly is associated with Alzheimer's disease. We find that prefibrillar aggregates and mature fibrils are distributed into distinct subcellular compartments and undergo varying degrees of morphological change over time, observations that shed new light on the origins of their differential toxicity and the mechanisms of their clearance. In addition, the results show that SE-EM provides a powerful and potentially widely applicable means to define the nature and location of protein assemblies in situ and to provide detailed and specific information about their partitioning and processing.
Department of Materials, Imperial College , Exhibition Road, London SW7 2AZ, United Kingdom.
Eva K
EK
McGuire
Michael
M
Motskin
Benedetta
B
Bolognesi
Shane D
SD
Bergin
Tuomas P J
TP
Knowles
Jeremy
J
Skepper
Leila M
LM
Luheshi
David W
DW
McComb
Christopher M
CM
Dobson
Alexandra E
AE
Porter
D016229:Amyloid beta-Peptides / Q000737:chemistry*; D002478:Cells, Cultured; D003287:Contrast Media; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008264:Macrophages / Q000378:metabolism* / Q000648:ultrastructure*; D008854:Microscopy, Electron / Q000379:methods*; D046912:Multiprotein Complexes / Q000648:ultrastructure*; D011485:Protein Binding; D017510:Protein Folding; D012643:Selenium
D016229:Amyloid beta-Peptides; D003287:Contrast Media; D046912:Multiprotein Complexes; D012643:Selenium