Suppression of sulfonylurea- and glucose-induced insulin secretion in vitro and in vivo in mice lacking the chloride transport protein ClC-3.

Journal article

Priming of insulin secretory granules for release requires intragranular acidification and depends on vesicular Cl(-)-fluxes, but the identity of the chloride transporter/ion channel involved is unknown. We tested the hypothesis that the chloride transport protein ClC-3 fulfills these actions in pancreatic beta cells. In ClC-3(-/-) mice, insulin secretion evoked by membrane depolarization (high extracellular K(+), sulfonylureas), or glucose was >60% reduced compared to WT animals. This effect was mirrored by a approximately 80% reduction in depolarization-evoked beta cell exocytosis (monitored as increases in cell capacitance) in single ClC-3(-/-) beta cells, as well as a 44% reduction in proton transport across the granule membrane. ClC-3 expression in the insulin granule was demonstrated by immunoblotting, immunostaining, and negative immuno-EM in a high-purification fraction of large dense-core vesicles (LDCVs) obtained by phogrin-EGFP labeling. The data establish the importance of granular Cl(-) fluxes in granule priming and provide direct evidence for the involvement of ClC-3 in the process.

Authors: Li, D; Jing, X; Salehi, A; Collins, S; Hoppa, M

• Publication status: Published
• Journal: Cell metabolism
• Volume: 10
• Issue: 4
• Pages: 309-315
• Publication date: 2009-10-01
• DOI: 10.1016/j.cmet.2009.08.011
• EISSN: 1932-7420
• ISSN: 1550-4131
• Language: English
• Keywords: Chloride Channels; Insulin; Glucagon-Like Peptide 1; Sulfonylurea Compounds; Mice; Glucose; Calcium; Mice, Knockout; Chlorides; RNA Interference; Cytoplasmic Granules; Animals; Insulin-Secreting Cells