Prostaglandin E1 inhibits endocytosis in the β-cell endocytosis

Abstract

Prostaglandins inhibit insulin secretion in a manner similar to that of norepinephrine (NE) and somatostatin. As NE inhibits endocytosis as well as exocytosis, we have now examined the modulation of endocytosis by prostaglandin E 1 (PGE 1 ). Endocytosis following exocytosis was recorded by whole-cell patch clamp capacitance measurements in INS-832/13 cells. Prolonged depolarizing pulses producing a high level of Ca 2+ influx were used to stimulate maximal exocytosis and to deplete the readily releasable pool (RRP) of granules. This high Ca 2+ influx eliminates the inhibitory effect of PGE 1 on exocytosis and allows specific characterization of the inhibitory effect of PGE 1 on the subsequent compensatory endocytosis. After stimulating exocytosis, endocytosis was apparent under control conditions but was inhibited by PGE 1 in a Pertussis toxin-sensitive (PTX)-insensitive manner. Dialyzing a synthetic peptide mimicking the C-terminus of the α-subunit of the heterotrimeric G-protein G z into the cells blocked the inhibition of endocytosis by PGE 1 , whereas a control-randomized peptide was without effect. These results demonstrate that PGE 1 inhibits endocytosis and G z mediates the inhibition.

Drug testing complementary metal‐oxide‐semiconductor chip reveals drug modulation of transmitter release for potential therapeutic applications

“…Standard whole‐cell patch‐clamp recordings were performed as previously described (Zhao et al ) to measure capacitance changes and Ca 2+ currents and determine readily release pool (RRP) size. Patch pipettes were pulled to have resistances of around 3 MΩ with intracellular solutions.…”

The Combination of Whole Cell Lipidomics Analysis and Single Cell Confocal Imaging of Fluidity and Micropolarity Provides Insight into Stress-Induced Lipid Turnover in Subcellular Organelles of Pancreatic Beta Cells

“…These metabolites subsequently regulate various cellular functions in autocrine and/or paracrine fashions. It has been shown that endogenous PUFA metabolites, such as 20-hydroperoxyeicosatetraenoic acid (20-HETE), prostaglandin E1, E3, J2 and I2, or endocannabinoids regulate beta cell functions [14,16,29,30,31,32,33,34,35,36,37,38,39]. Some of these mediators are also generated in beta cells by direct enzymatic transformation of exogenously available unsaturated fatty acids; it has been shown that certain metabolites improved insulin secretion and ameliorate obesity- and cytokine-induced beta cell damage [16,40,41].…”