1. Novel Purine Derivative ITH15004 Facilitates Exocytosis through a Mitochondrial Calcium-Mediated Mechanism.
- Author
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de Pascual R, Calzaferri F, Gonzalo PC, Serrano-Nieto R, de Los Ríos C, García AG, and Gandía L
- Subjects
- Animals, Cattle, Calcium Signaling, Cells, Cultured, Primary Cell Culture, Calcium metabolism, Catecholamines metabolism, Chromaffin Cells cytology, Chromaffin Cells drug effects, Exocytosis drug effects, Mitochondria drug effects
- Abstract
Upon depolarization of chromaffin cells (CCs), a prompt release of catecholamines occurs. This event is triggered by a subplasmalemmal high-Ca
2+ microdomain (HCMD) generated by Ca2+ entry through nearby voltage-activated calcium channels. HCMD is efficiently cleared by local mitochondria that avidly take up Ca2+ through their uniporter (MICU), then released back to the cytosol through mitochondrial Na+ /Ca2+ exchanger (MNCX). We found that newly synthesized derivative ITH15004 facilitated the release of catecholamines triggered from high K+ -depolarized bovine CCs. Such effect seemed to be due to regulation of mitochondrial Ca2+ circulation because: (i) FCCP-potentiated secretory responses decay was prevented by ITH15004; (ii) combination of FCCP and ITH15004 exerted additive secretion potentiation; (iii) such additive potentiation was dissipated by the MICU blocker ruthenium red (RR) or the MNCX blocker CGP37157 (CGP); (iv) combination of FCCP and ITH15004 produced both additive augmentation of cytosolic Ca2+ concentrations ([Ca2+ ]c ) K+ -challenged BCCs, and (v) non-inactivated [Ca2+ ]c transient when exposed to RR or CGP. On pharmacological grounds, data suggest that ITH15004 facilitates exocytosis by acting on mitochondria-controlled Ca2+ handling during K+ depolarization. These observations clearly show that ITH15004 is a novel pharmacological tool to study the role of mitochondria in the regulation of the bioenergetics and exocytosis in excitable cells.- Published
- 2021
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