Visualization of Partial Exocytotic Content Release and Chemical Transport into Nanovesicles in Cells
Journal article, 2022

For decades, "all-or-none"and "kiss-and-run"were thought to be the only major exocytotic release modes in cell-to-cell communication, while the significance of partial release has not yet been widely recognized and accepted owing to the lack of direct evidence for exocytotic partial release. Correlative imaging with transmission electron microscopy and NanoSIMS imaging and a dual stable isotope labeling approach was used to study the cargo status of vesicles before and after exocytosis; demonstrating a measurable loss of transmitter in individual vesicles following stimulation due to partial release. Model secretory cells were incubated with 13C-labeled l-3,4-dihydroxyphenylalanine, resulting in the loading of 13C-labeled dopamine into their vesicles. A second label, di-N-desethylamiodarone, having the stable isotope 127I, was introduced during stimulation. A significant drop in the level of 13C-labeled dopamine and a reduction in vesicle size, with an increasing level of 127I-, was observed in vesicles of stimulated cells. Colocalization of 13C and 127I- in several vesicles was observed after stimulation. Thus, chemical visualization shows transient opening of vesicles to the exterior of the cell without full release the dopamine cargo. We present a direct calculation for the fraction of neurotransmitter release from combined imaging data. The average vesicular release is 60% of the total catecholamine. An important observation is that extracellular molecules can be introduced to cells during the partial exocytotic release process. This nonendocytic transport process appears to be a general route of entry that might be exploited pharmacologically.

partial release

fraction of neurotransmitter release

exocytosis

nanosims

nanoimaging

Author

Tho Duc Khanh Nguyen

University of Gothenburg

Lisa Mellander

University of Gothenburg

Alicia Lork

University of Gothenburg

Aurélien Thomen

University of Gothenburg

Thuy Mai Hoang Philipsen

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Michael Kurczy

AstraZeneca AB

Nhu TN Phan

University of Gothenburg

Andrew Ewing

University of Gothenburg

ACS Nano

1936-0851 (ISSN) 1936-086X (eISSN)

Vol. 16 3 4831-4842

Electrochemical Cytometry and NanoSIMS Analysis of Transmitter Vesicles

Swedish Research Council (VR) (2017-04366), 2018-01-01 -- 2021-12-31.

Subject Categories

Cell Biology

Neurosciences

Cell and Molecular Biology

DOI

10.1021/acsnano.2c00344

PubMed

35189057

More information

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3/7/2024 9