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Neuroreport. 2014 Nov 12;25(16):1281-8. doi: 10.1097/WNR.0000000000000260.

Beta-amyloid oligomers induce early loss of presynaptic proteins in primary neurons by caspase-dependent and proteasome-dependent mechanisms.

Author information

1
Department of Anatomy and Neurobiology, College of Medicine, Hallym University, Gangwon-Do, Korea.

Abstract

Beta-amyloid is a major pathogenic molecule for Alzheimer's disease (AD) and can be aggregated into a soluble oligomer, which is a toxic intermediate, before amyloid fibril formation. Beta-amyloid oligomers are associated closely with early synaptic loss in AD. However, it is still unknown which synaptic proteins are involved in the synaptotoxicity, and a direct comparison among the synaptic proteins should also be addressed. Here, we investigated changes in the expression of several presynaptic and postsynaptic proteins in primary neurons after treatment with a low-molecular weight and a high-molecular weight beta-amyloid oligomer. Both oligomers induced early neuronal dysfunction after 4 h and significantly reduced presynaptic protein (synaptophysin, syntaxin, synapsin, and synaptotagmin) expression. However, the expression of postsynaptic proteins (PSD95, NMDAR2A/B, and GluR2/3), except NMDAR1 was not reduced, and some protein expression levels were increased. Glutamate treatment, which is correlated with postsynaptic activation, showed more postsynaptic-specific protein loss compared with beta-amyloid oligomer treatment. Finally, the caspase inhibitor zVAD and the proteasomal inhibitor MG132 attenuated presynaptic protein loss. Thus, our data showed changes in synaptic proteins by beta-amyloid oligomers, which provides an understanding of early synaptotoxicity and suggests new approaches for AD treatment.

PMID:
25275636
DOI:
10.1097/WNR.0000000000000260
[Indexed for MEDLINE]

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