Opposite effect of cAMP signaling in endothelial barriers of different origin

• Published in: American Journal of Physiology: Cell Physiology 2004-11, Vol.287 (5), p.C1246-C1255
• Main Authors: Bindewald, K, Gunduz, D, Hartel, F, Peters, S. C, Rodewald, C, Nau, S, Schafer, M, Neumann, J, Piper, H. M, Noll, T
• Format: Article
• Language: English
• Subjects: Animals; Aorta - cytology; Aorta - physiology; Cell Adhesion - physiology; Cells, Cultured; Coronary Vessels - cytology; Coronary Vessels - physiology; Cyclic AMP - metabolism; Cyclic AMP-Dependent Protein Kinases; Endothelial Cells - metabolism; Endothelial Cells - ultrastructure; Endothelium, Vascular - metabolism; Endothelium, Vascular - ultrastructure; Enzyme Activation - physiology; Intercellular Junctions - ultrastructure; Male; Microscopy, Fluorescence; Myosin Light Chains - metabolism; Myosin-Light-Chain Kinase - metabolism; Myosin-Light-Chain Phosphatase - metabolism; Protein-Serine-Threonine Kinases - metabolism; Rats; Rats, Wistar; Signal Transduction - physiology; Swine
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.00132.2004

1 Physiologisches Institut, Justus-Liebig-Universität, D-35392 Giessen; and 2 Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität, D-48149 Münster, Germany Submitted 8 March 2004 ; accepted in final form 21 June 2004 cAMP-mediated signaling mechanisms may destabilize or stabilize the endothelial barrier, depending on the origin of endothelial cells. Here, microvascular coronary [coronary endothelial cells (CEC)] and macrovascular aortic endothelial cell (AEC) monolayers with opposite responses to cAMP were analyzed. Macromolecule permeability, isometric force, activation state of contractile machinery [indicated by phosphorylation of regulatory myosin light chains (MLC), activity of MLC kinase, and MLC phosphatase], and dynamic changes of adhesion complex proteins (translocation of VE-cadherin and paxillin) were determined. cAMP signaling was stimulated by the adenosine receptor agonist 5'- N -(ethylcarboxamido)-adenosine (NECA), the -adrenoceptor agonist isoproterenol (Iso), or by the adenylyl cyclase activator forskolin (FSK). Permeability was increased in CEC and decreased in AEC on stimulation with NECA, Iso, or FSK. The effects could be inhibited by the PKA inhibitor Rp-8-CPT-cAMPS and imitated by the PKA activator Sp-cAMPS. Under cAMP/PKA-dependent stimulation, isometric force and MLC phosphorylation were reduced in monolayers of either cell type, due to an activation of MLC phosphatase. In CEC but not in AEC, FSK induced delocalization of VE-cadherin and paxillin from cellular adhesion complexes as indicated by cell fractionation and immunofluorescence microscopy. In conclusion, decline in contractile activation and isometric force contribute to cAMP/PKA-mediated stabilization of barrier function in AEC. In CEC, this stabilizing effect is overruled by cAMP-induced disintegration of cell adhesion structures. endothelial cell adhesion; endothelial permeability; isometric force; myosin light chain kinase; myosin light chain phosphatase Address for reprint requests and other correspondence: T. Noll, Physiologisches Institut, Justus-Liebig-Universität, Aulweg 129, D-35392 Giessen, Germany (E-mail: thomas.noll{at}physiologie.med.uni-giessen.de )