Intracellular amyloid β oligomers impair organelle transport and induce dendritic spine loss in primary neurons

Research

Umeda, Tomohiro / Ramser, Elisa M. / Yamashita, Minato / Nakajima, Koichi / Mori, Hiroshi / Silverman, Michael A. / Tomiyama, Takami

梅田, 知宙 / / 山下, 港 / 中嶋, 弘一 / 森, 啓 / / 富山, 貴美

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Introduction: Synaptic dysfunction and intracellular transport defects are early events in Alzheimer's disease (AD). Extracellular amyloid β (Aβ) oligomers cause spine alterations and impede the transport of proteins and organelles such as brain-derived neurotrophic factor (BDNF) and mitochondria that are required for synaptic function. Meanwhile, intraneuronal accumulation of Aβ precedes its extracellular deposition and is also associated with synaptic dysfunction in AD. However, the links between intracellular Aβ, spine alteration, and mechanisms that support synaptic maintenance such as organelle trafficking are poorly understood. / Results: We compared the effects of wild-type and Osaka (E693Δ)-mutant amyloid precursor proteins: the former secretes Aβ into extracellular space and the latter accumulates Aβ oligomers within cells. First we investigated the effects of intracellular Aβ oligomers on dendritic spines in primary neurons and their tau-dependency using tau knockout neurons. We found that intracellular Aβ oligomers caused a reduction in mushroom, or mature spines, independently of tau. We also found that intracellular Aβ oligomers significantly impaired the intracellular transport of BDNF, mitochondria, and recycling endosomes: cargoes essential for synaptic maintenance. A reduction in BDNF transport by intracellular Aβ oligomers was also observed in tau knockout neurons. / Conclusions: Our findings indicate that intracellular Aβ oligomers likely contribute to early synaptic pathology in AD and argue against the consensus that Aβ-induced spine loss and transport defects require tau.

This study was supported by the Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan (no. 23110514, 24659434, 25290018); by the Grantsin-Aid from the Ministry of Health, Labour, and Welfare, Japan; and in part by the Strategic Research Program for Brain Sciences (CREST), the Ministry of Education, Culture, Sports, Science and Technology of Japan, and the Canadian Institute for Health Research (no. 90396) to M.A.S. For initiating this work, M.A.S. thanks the Japanese Society for Promotion of Science Long-Term Invitation Fellowship (#L11710).

eng

51

publisher

Osaka City University, Japan Science and Technology Agency / Simon Fraser University / Osaka City University / Osaka City University / Japan Science and Technology Agency, Osaka City University / Simon Fraser University / Osaka City University, Japan Science and Technology Agency

2015-08-21

BioMed Central

2051-5960

Journal Article

https://doi.org/10.1186/s40478-015-0230-2

この作品はクリエイティブ・コモンズ 表示 4.0 国際 ライセンスの下に提供されています。

© The Author(s). 2015