Trapping of Syntaxin1a in Presynaptic Nanoclusters by a Clinically Relevant General Anesthetic

• Published in: Cell reports (Cambridge) Vol. 22; no. 2; pp. 427 - 440
• Main Authors: Bademosi, Adekunle T., Steeves, James, Karunanithi, Shanker, Zalucki, Oressia H., Gormal, Rachel S., Liu, Shu, Lauwers, Elsa, Verstreken, Patrik, Anggono, Victor, Meunier, Frederic A., van Swinderen, Bruno
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 09-01-2018; Elsevier
• Subjects: Drosophila melanogaster; etomidate; neurotransmission; PC12; propofol; SNAP-25; SNARE; sptPALM; super-resolution microscopy; syntaxin1A; PC12; neurotransmission; syntaxin1A; propofol; etomidate; sptPALM; Drosophila melanogaster; super-resolution microscopy; SNAP-25; SNARE
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2017.12.054

Propofol is the most commonly used general anesthetic in humans. Our understanding of its mechanism of action has focused on its capacity to potentiate inhibitory systems in the brain. However, it is unknown whether other neural mechanisms are involved in general anesthesia. Here, we demonstrate that the synaptic release machinery is also a target. Using single-particle tracking photoactivation localization microscopy, we show that clinically relevant concentrations of propofol and etomidate restrict syntaxin1A mobility on the plasma membrane, whereas non-anesthetic analogs produce the opposite effect and increase syntaxin1A mobility. Removing the interaction with the t-SNARE partner SNAP-25 abolishes propofol-induced syntaxin1A confinement, indicating that syntaxin1A and SNAP-25 together form an emergent drug target. Impaired syntaxin1A mobility and exocytosis under propofol are both rescued by co-expressing a truncated syntaxin1A construct that interacts with SNAP-25. Our results suggest that propofol interferes with a step in SNARE complex formation, resulting in non-functional syntaxin1A nanoclusters.
[Display omitted]
•Propofol impairs presynaptic release of neurotransmitters•Propofol and etomidate restrict syntaxin1A mobility on presynaptic membranes•Non-anesthetic analogs of propofol increase syntaxin1A mobility•A propofol target emerges from an interaction between syntaxin1A and SNAP-25
Bademosi et al. use single-molecule imaging microscopy to understand how general anesthetics might affect presynaptic release mechanisms. They find that a clinically relevant concentration of propofol targets the presynaptic release machinery by specifically restricting syntaxin1A mobility on the plasma membrane. This suggests an alternate target process for these drugs.