Amyloid-β Oligomers May Impair SNARE-Mediated Exocytosis by Direct Binding to Syntaxin 1a

• Published in: Cell reports (Cambridge) 2015-08, Vol.12 (8), p.1244-1251
• Main Authors: Yang, Yoosoo, Kim, Jaewook, Kim, Hye Yun, Ryoo, Nayeon, Lee, Sejin, Kim, YoungSoo, Rhim, Hyewhon, Shin, Yeon-Kyun
• Format: Article
• Language: English
• Subjects: Amyloid beta-Peptides - metabolism; Animals; Brain - metabolism; Exocytosis; Mice; Protein Binding; Protein Multimerization; Syntaxin 1 - metabolism
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2015.07.044

Alzheimer’s disease (AD) is closely associated with synaptic dysfunction, and thus current treatments often aim to stimulate neurotransmission to improve cognitive impairment. Whereas the formation of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex is essential for synaptic transmission, the correlation between SNAREs and AD neuropathology is unknown. Here, we report that intracellular amyloid-β (Aβ) oligomers directly inhibit SNARE-mediated exocytosis by impairing SNARE complex formation. We observe abnormal reduction of SNARE complex levels in the brains of APP/PS1 transgenic (TG) mice compared to age-matched wild-types. We demonstrate that Aβ oligomers block SNARE complex assembly through the direct interaction with a target membrane (t)-SNARE syntaxin 1a in vitro. Furthermore, the results of the in vitro single-vesicle content-mixing assay reveal that Aβ oligomers inhibit SNARE-mediated fusion pores. Thus, our study identifies a potential molecular mechanism by which intracellular Aβ oligomers hamper SNARE-mediated exocytosis, likely leading to AD-associated synaptic dysfunctions. [Display omitted] •SNARE complex formation is reduced in APP/PS1 mice•Aβ oligomers inhibit SNARE complex formation•Aβ binds to the SNARE motif of syntaxin 1a•Aβ oligomers inhibit SNARE-mediated vesicle fusion The role of Aβ in cognitive impairment in Alzheimer’s disease still remains elusive. Yang et al. now show that Aβ oligomers bind to syntaxin 1a to impair SNARE complex formation to inhibit exocytosis. The resulting inhibition of neurotransmission could therefore lead to cognitive impairments.