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Vesicular Release Dynamics are Altered by Interaction between Chemical Cargo and Vesicle Membrane Lipids

preprint
submitted on 23.04.2021, 11:41 and posted on 26.04.2021, 14:11 by Farzaneh Asadpour, Xinwei Zhang, Mohammad Mazloum-Ardakani, Maysam Mirzaei, Soodabeh Majdi, Andrew Ewing
We used liposomes loaded with different monoamines, dopamine (DA) and serotonin (5-HT), to simulate vesicular release and to monitor the dynamics of chemical release from isolated vesicles during vesicle impact electrochemical cytometry (VIEC). The release of DA from liposomes presents a longer release time compared to 5-HT. Modelling the release time showed that DA filled vesicles had a higher percentage of events where the time for the peak fall was better fit to a double exponential (DblExp) decay function, suggesting multiple kinetic steps in the release. By fitting to a desorption-release model, where the transmitters adsorbed to the vesicle membrane, the dissociation rates of DA and 5-HT from liposome membrane were estimated. DA has a lower desorption rate constant, which leads to slower DA release than that observed for 5-HT, whereas there is little difference in pore size. The alteration of vesicular release dynamics due to the interaction between chemical cargo and vesicle membrane lipids provides an important mechanism to regulate vesicular release in chemical and physiological processes. It is highly possible that this introduces a fundamental chemical regulation difference between transmitters during exocytosis.

Funding

European Research Council Advanced Grant, NanoBioNext 787534

Knut and Alice Wallenberg Scholar grant

Vetenskapsrådet 2017-04366

Iran National Science Foundation (INSF)

History

Email Address of Submitting Author

Andrew.ewing@chem.gu.se

Institution

University of Gothenburg

Country

Sweden

ORCID For Submitting Author

0000-0002-2084-0133

Declaration of Conflict of Interest

No conflict of interest

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