Cystatin C reduces the in vitro formation of soluble Abeta1-42 oligomers and protofibrils.
There are an increasing number of genetic and neuropathological observations to suggest that cystatin C, an extracellular protein produced by all nucleated cells, might play a role in the pathophysiology of sporadic Alzheimer's disease (AD). Recent observations indicate that small and large soluble oligomers of the beta-amyloid protein (Abeta) impair synaptic plasticity and induce neurotoxicity in AD. The objective of the present study was to investigate the influence of cystatin C on the production of such oligomers in vitro. Co-incubation of cystatin C with monomeric Abeta1-42 significantly attenuated the in vitro formation of Abeta oligomers and protofibrils, as determined using electron microscopy (EM), dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, thioflavin T (ThT) spectrofluorimetry and gel chromatography. However, cystatin C did not dissolve preformed Abeta oligomers. Direct binding of cystatin C to Abeta was demonstrated with the formation of an initial 1:1 molar high-affinity complex. These observations suggest that cystatin C might be a regulating element in the transformation of monomeric Abeta to larger and perhaps more toxic molecular species in vivo.
Selenica
M L
ML
Disease Biology, H. Lundbeck A/S, Copenhagen, Denmark.
Wang
X
X
Ostergaard-Pedersen
L
L
Westlind-Danielsson
A
A
Grubb
A
A
D016229:Amyloid beta-Peptides / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D052160:Benzothiazoles; D002850:Chromatography, Gel; D055316:Cystatin C; D015891:Cystatins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D015151:Immunoblotting; D066298:In Vitro Techniques; D046529:Microscopy, Electron, Transmission; D010446:Peptide Fragments / Q000378:metabolism* / Q000648:ultrastructure; D011480:Protease Inhibitors / Q000378:metabolism*; D011485:Protein Binding; D011994:Recombinant Proteins; D013050:Spectrometry, Fluorescence; D013844:Thiazoles / Q000032:analysis
D016229:Amyloid beta-Peptides; D052160:Benzothiazoles; D055316:Cystatin C; D015891:Cystatins; D010446:Peptide Fragments; D011480:Protease Inhibitors; D011994:Recombinant Proteins; D013844:Thiazoles; C078592:amyloid beta-protein (1-40); C075222:amyloid beta-protein (1-42); C009462:thioflavin T