Nanoscale Amperometry Reveals that Only a Fraction of Vesicular Serotonin Content is Released During Exocytosis from Beta Cells. Issue 14 (26th February 2021)

• Record Type: Journal Article
• Authors: Hatamie, Amir; Ren, Lin; Dou, Haiqiang; Gandasi, Nikhil R.; Rorsman, Patrik; Ewing, Andrew
• Is Part Of: Angewandte Chemie international edition. Volume 60:Issue 14(2021)
• Page Start: 7593
• Page End: 7596
• Publication Date: 2021-02-26
• Subjects: beta cells -- electrochemical analysis -- exocytosis -- nanoelectrodes -- partial release; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202015902
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Recent work has shown that chemical release during the fundamental cellular process of exocytosis in model cell lines is not all‐or‐none. We tested this theory for vesicular release from single pancreatic beta cells. The vesicles in these cells release insulin, but also serotonin, which is detectible with amperometric methods. Traditionally, it is assumed that exocytosis in beta cells is all‐or‐none. Here, we use a multidisciplinary approach involving nanoscale amperometric chemical methods to explore the chemical nature of insulin exocytosis. We amperometrically quantified the number of serotonin molecules stored inside of individual nanoscale vesicles (39 317±1611) in the cell cytoplasm before exocytosis and the number of serotonin molecules released from single cells (13 310±1127) for each stimulated exocytosis event. Thus, beta cells release only one‐third of their granule content, clearly supporting partial release in this system. We discuss these observations in the context of type‐2 diabetes. Abstract : Exocytosis from beta cells monitored by amperometry is compared to the vesicle content assessed from intracellular vesicle impact cytometry to determine if partial release is dominant. Serotonin was used as an electroactive proxy for insulin as it is co‐released. The fraction of release from insulin‐containing granules in beta cells was found to be at most 34 %, providing a new perspective on insulin release for diabetes research.