Calcium handling in porcine coronary endothelial cells by gastrin-17

Abstract

In porcine coronary artery endothelial cells (PCAEC), gastrin-17 has recently been found to increase nitric oxide (NO) production by the endothelial NO synthase (eNOS) isoform through cholecystokinin 1/2 (CCK1/2) receptors and the involvement of protein kinase A (PKA), PKC and the b 2 -adrenoreceptor-related pathway. As eNOS is the Ca 2C -dependent isoform of the enzyme, we aimed to examine the effects of gastrin-17 on Ca 2C movements.Thus, experiments were performed in Fura-2-acetoxymethyl-ester-loaded PCAEC, where changes of cytosolic Ca 2C ([Ca 2C ] c ) caused by gastrin-17 were analysed and compared with those of CCK receptors and b 2 -adrenoreceptors agonists/antagonists. In addition, some experiments were performed by stimulating cells with gastrin-17 in the presence or absence of cAMP/PKA activator/inhibitor and of phospholipase C (PLC) and Ca 2C-calmodulin dependent protein kinase II (CaMKII) blockers. The results have shown that gastrin-17 can promote a transient increase in [Ca 2C ] c mainly originating from an intracellular pool sensitive to thapsigargin and from the extracellular space. In addition, the response of cells to gastrin-17 was increased by the adenylyl cyclase activator and the b 2 -adrenoreceptor agonists and affected mainly by the CCK2 receptor agonists/antagonists. Moreover, the effects of gastrin-17 were prevented by b 2 -adrenoreceptors and CaMKII blockers and the adenylyl cyclase/PKA and PLC inhibitors. Finally, in PCAEC cultured in Na C -free medium or loaded with the plasma membrane Ca 2C pump inhibitor, the gastrin-17-evoked Ca 2C transient was long lasting.In conclusion, this study shows that gastrin-17 affected intracellular Ca 2C homeostasis in PCAEC by both promoting a discharge of an intracellular pool and by interfering with the operation of store-dependent channels through mainly CCK2 receptors and PKA/PLC-and CaMKII-related signalling downstream of b 2 -adrenoreceptor stimulation.

Progastrin Stimulates Colonic Cell Proliferation via CCK2R- and β-Arrestin–Dependent Suppression of BMP2

“…39 Our finding that progastrin also binds to the CCK2R was initially somewhat puzzling, since studies to date have not shown the activation of classical GPCR signaling pathways by progastrin stimulation. Thus, while numerous G protein-coupled pathways have been linked to signaling by amidated gastrin through the CCK2R, including Ca 2+ and ERK signaling, 40 we show for the first time that progastrin signals not through classical G protein-coupling, but rather through a beta-arrestin pathway. In contrast to amidated gastrin, progastrin failed to activate intracellular calcium fluxes, a classical measure of Gq-mediated activation of protein kinase C. Furthermore, progastrin-dependent proliferation was blocked by siRNAs directed against beta-arrestin 1 and 2.…”

Gastrin exerts a protective effect against myocardial infarction via promoting angiogenesis

“…The gastrin peptide family has two subtype receptors, namely, CCK 1 R and CCK 2 R. The expression of CCK 2 R is greater than CCK 1 R in the coronary arteries and has a higher affinity for gastrin than CCK 1 R (Grossini et al 2013 ). Gastrin has been reported to up-regulate NO production in the artery, and the intracoronary infusion of gastrin significantly increased coronary blood flow through stimulating CCK 2 R in pigs (Grossini et al 2011 ).…”

“…Additionally, gastrin is expressed in the heart and blood vessels (Gersl et al 1981 ; Grossini et al 2011 ). Two different studies reported that gastrin promoted a transient increase of Ca 2+ (Grossini et al 2013 ) and up-regulated nitric oxide production in porcine coronary artery endothelial cells (Grossini et al 2012 ). Moreover, another study showed that gastrin increased coronary blood flow and myocardial contractility, dose-dependently, through intracoronary infusion in anesthetized pigs (Grossini et al 2011 ).…”

Asenapine modulates nitric oxide release and calcium movements in cardiomyoblasts

“…). [14][15][16] The fluorescence intensities obtained were corrected for cell autofluorescence at the wavelengths employed. [16] The results obtained were examined through one-way ANOVA followed by Newman-Keuls post hoc test.…”

“…Quantification of (Ca 2+ ) c was conventionally obtained by measuring the Fura-2/AM fluorescence in Ca 2+ -free (0.1 M EGTA) and Ca 2+ -saturated conditions by the equation (Ca 2+ ) c = K d ([ R − R min ]/[ R max − R ]). [ 14 15 16 ] The fluorescence intensities obtained were corrected for cell autofluorescence at the wavelengths employed. [ 16 ]…”