Quantitation of Alzheimer's amyloid peptide and identification of related amyloid proteins by dot-blot immunoassay.
In Alzheimer's disease, the main component of amyloid deposits is a 39-43 amino acid peptide referred to as amyloid peptide or A beta. A crucial issue in the study of this disorder is to define the sequence of events that lead to amyloid deposition. In the present study, a new approach was developed that allows to specifically solubilize A beta peptide trapped within amyloid deposits and to quantify its amount by dot-blot immunoassay. The present method also permits to isolate components tightly bound to A beta and that are likely to catalyze its aggregation. Biochemical A beta quantitation was performed in 4 Brodmann areas from 17 elderly individuals exhibiting different degrees of amyloidosis. In parallel, classical neuropathology was done by histochemical and immunohistochemical methods. A beta amounts (pmol) were correlated to the number of amyloid deposits determined by neuropathology showing high statistical significance. Moreover, amyloid-binding proteins including apolipoprotein E and heparan sulfate proteoglycans were also found associated to A beta in the amyloid preparation. The present biochemical procedure is a new and reliable method to quantify amyloid deposition in brain. Furthermore, it allows to detect amyloid-associated components such as apolipoprotein E, that may be involved in the pathological process of amyloidogenesis.
Permanne
B
B
INSERM U422, Lille, France.
Buée
L
L
David
J P
JP
Fallet-Bianco
C
C
Di Menza
C
C
Delacourte
A
A
D000368:Aged; D016229:Amyloid beta-Peptides / Q000032:analysis*; D001921:Brain / Q000473:pathology; D001923:Brain Chemistry / Q000502:physiology*; D016022:Case-Control Studies; D002384:Catalysis; D006651:Histocytochemistry; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D016014:Linear Models; D009419:Nerve Tissue Proteins / Q000032:analysis*; D012995:Solubility
D016229:Amyloid beta-Peptides; D009419:Nerve Tissue Proteins