Real‐time monitoring of cAMP levels in living endothelial cells: thrombin transiently inhibits adenylyl cyclase 6

Abstract

The crosstalk between Ca2+ and cAMP signals plays a significant role for the regulation of the endothelial barrier function. The Ca 2+ -elevating agent thrombin was demonstrated to increase endothelial permeability and to decrease cAMP levels. Since Ca

Intracellular Ascorbate Prevents Endothelial Barrier Permeabilization by Thrombin

“…Protease-activated receptor activation by thrombin both inhibits adenylate cyclase via G i (35) and activates PDE3, a cGMP-inhibited cAMP phosphodiesterase (36,37). The resulting decrease in cAMP impairs the function of signaling pathways involving both protein kinase A and Epac1.…”

Fluorescence/Bioluminescence Resonance Energy Transfer Techniques to Study G-Protein-Coupled Receptor Activation and Signaling

“…Although it has been possible to generate images of primary cells or of functional units such as thyroid follicles or pancreatic islets isolated from mice transgenically expressing second-messenger sensors Calebiro et al, 2009;Mironov et al, 2009;von Hayn et al, 2010;Werthmann et al, 2009Werthmann et al, , 2011, the high degree of background fluorescence calls for several improvements for in vivo microscopy, including red-shifted sensors and FRET analysis by multiphoton and second harmonic generation microscopy (Provenzano et al, 2009). In addition, BRET studies have been performed in cells isolated from transgenic mice expressing luciferaselabeled ␤ 2 -adrenergic receptors and GFP2-labeled ␤-arrestin2 (Audet et al, 2010).…”

Dynamics of adenylate cyclase regulation via heterotrimeric G-proteins

“…In contrast, activation of β 1 -ARs results in cAMP signals reaching through the whole cell [18,19]. In both vascular endothelial cells and smooth muscle cells, G q -mediated Ca 2 + release leads to a robust negative regulation of cAMP levels if these were pre-elevated by stimulation of β 2 -AR [20,21]. As controlled by single-cell Ca 2 + imaging, purinergic stimulation (VSMCs) or exposure to thrombin [HUVECs (human umbilical vein endothelial cells)] led to a rapid rise in intracellular Ca 2 + that preceded the G q -mediated decline in cAMP.…”

“…As controlled by single-cell Ca 2 + imaging, purinergic stimulation (VSMCs) or exposure to thrombin [HUVECs (human umbilical vein endothelial cells)] led to a rapid rise in intracellular Ca 2 + that preceded the G q -mediated decline in cAMP. On the basis of our observations that the inhibition was insensitive to pertussis toxin pre-treatment, but attenuated by pre-incubation with the Ca 2 + -chelator BAPTA/AM [1,2-bis-(o-aminophenoxy)ethane-N,N,N ,Ntetra-acetic acid tetrakis(acetoxymethyl ester)], we concluded that the reduction in cAMP following stimulation of G qcoupled receptors was regulated directly by Ca 2 + [20,21]. Furthermore, siRNA-mediated knockdown of AC5 and AC6 attenuated the ability of UDP/ADP or thrombin to reduce cAMP levels in VSMCs and HUVECs respectively.…”