%0 Journal Article %1 Baumer2009 %A Baumer, Y. %A Spindler, V. %A Werthmann, R. C. %A Bunemann, M. %A Waschke, J. %D 2009 %J J Cell Physiol %K *Signal AMP/analogs Activators/pharmacology Aminoquinolines/pharmacology Antigens, Biosensing CD/metabolism Cadherins/metabolism Calcium/metabolism Capillary Cells/drug Cultured Cyclic Electric Endothelial Energy Enzyme Factors Fluorescence Forskolin/pharmacology GTP-Binding Gap Humans Impedance Inhibitors/pharmacology Junctions/drug Microscopy, Permeability/drug Protein/antagonists Protein/metabolism Pyrimidines/pharmacology Resonance Rolipram/pharmacology Techniques Thrombin/*metabolism Time Transduction/drug Transfer cdc42 derivatives/*metabolism/pharmacology effects effects/*enzymology inhibitors/*metabolism rac1 Cell %N 3 %P 716-26 %T Role of Rac 1 and cAMP in endothelial barrier stabilization and thrombin-induced barrier breakdown %U http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19472214 %V 220 %X Barrier stabilizing effects of cAMP as well as of the small GTPase Rac 1 are well established. Moreover, it is generally believed that permeability-increasing mediators such as thrombin disrupt endothelial barrier functions primarily via activation of Rho A. In this study, we provide evidence that decrease of both cAMP levels and of Rac 1 activity contribute to thrombin-mediated barrier breakdown. Treatment of human dermal microvascular endothelial cells (HDMEC) with Rac 1-inhibitor NSC-23766 decreased transendothelial electrical resistance (TER) and caused intercellular gap formation. These effects were reversed by addition of forskolin/rolipram (F/R) to increase intracellular cAMP but not by the cAMP analogue 8-pCPT-2'-O-Methyl-cAMP (O-Me-cAMP) which primarily stimulates protein kinase A (PKA)-independent signaling via Epac/Rap 1. However, both F/R and O-Me-cAMP did not increase TER above control levels in the presence of NSC-23766 in contrast to experiments without Rac 1 inhibition. Because Rac 1 was required for maintenance of barrier functions as well as for cAMP-mediated barrier stabilization, we tested the role of Rac 1 and cAMP in thrombin-induced barrier breakdown. Thrombin-induced drop of TER and intercellular gap formation were paralleled by a rapid decrease of cAMP as revealed by fluorescence resonance energy transfer (FRET). The efficacy of F/R or O-Me-cAMP to block barrier-destabilizing effects of thrombin was comparable to Y27632-induced inhibition of Rho kinase but was blunted when Rac 1 was inactivated by NSC-23766. Taken together, these data indicate that decrease of cAMP and Rac 1 activity may be an important step in inflammatory barrier disruption.

@article{Baumer2009, abstract = {Barrier stabilizing effects of cAMP as well as of the small GTPase Rac 1 are well established. Moreover, it is generally believed that permeability-increasing mediators such as thrombin disrupt endothelial barrier functions primarily via activation of Rho A. In this study, we provide evidence that decrease of both cAMP levels and of Rac 1 activity contribute to thrombin-mediated barrier breakdown. Treatment of human dermal microvascular endothelial cells (HDMEC) with Rac 1-inhibitor NSC-23766 decreased transendothelial electrical resistance (TER) and caused intercellular gap formation. These effects were reversed by addition of forskolin/rolipram (F/R) to increase intracellular cAMP but not by the cAMP analogue 8-pCPT-2'-O-Methyl-cAMP (O-Me-cAMP) which primarily stimulates protein kinase A (PKA)-independent signaling via Epac/Rap 1. However, both F/R and O-Me-cAMP did not increase TER above control levels in the presence of NSC-23766 in contrast to experiments without Rac 1 inhibition. Because Rac 1 was required for maintenance of barrier functions as well as for cAMP-mediated barrier stabilization, we tested the role of Rac 1 and cAMP in thrombin-induced barrier breakdown. Thrombin-induced drop of TER and intercellular gap formation were paralleled by a rapid decrease of cAMP as revealed by fluorescence resonance energy transfer (FRET). The efficacy of F/R or O-Me-cAMP to block barrier-destabilizing effects of thrombin was comparable to Y27632-induced inhibition of Rho kinase but was blunted when Rac 1 was inactivated by NSC-23766. Taken together, these data indicate that decrease of cAMP and Rac 1 activity may be an important step in inflammatory barrier disruption.}, added-at = {2010-12-14T18:12:02.000+0100}, author = {Baumer, Y. and Spindler, V. and Werthmann, R. C. and Bunemann, M. and Waschke, J.}, biburl = {https://www.bibsonomy.org/bibtex/262715cb8eb5d5c44c0c87bc755142347/pharmawuerz}, endnotereftype = {Journal Article}, groups = {private}, interhash = {0eb6bd184789c3b2f12b4662dabddb4b}, intrahash = {62715cb8eb5d5c44c0c87bc755142347}, issn = {1097-4652 (Electronic) 1097-4652 (Linking)}, journal = {J Cell Physiol}, keywords = {*Signal AMP/analogs Activators/pharmacology Aminoquinolines/pharmacology Antigens, Biosensing CD/metabolism Cadherins/metabolism Calcium/metabolism Capillary Cells/drug Cultured Cyclic Electric Endothelial Energy Enzyme Factors Fluorescence Forskolin/pharmacology GTP-Binding Gap Humans Impedance Inhibitors/pharmacology Junctions/drug Microscopy, Permeability/drug Protein/antagonists Protein/metabolism Pyrimidines/pharmacology Resonance Rolipram/pharmacology Techniques Thrombin/*metabolism Time Transduction/drug Transfer cdc42 derivatives/*metabolism/pharmacology effects effects/*enzymology inhibitors/*metabolism rac1 Cell}, month = Sep, note = {Baumer, Y Spindler, V Werthmann, R C Bunemann, M Waschke, J Research Support, Non-U.S. Gov't United States Journal of cellular physiology J Cell Physiol. 2009 Sep;220(3):716-26.}, number = 3, pages = {716-26}, shorttitle = {Role of Rac 1 and cAMP in endothelial barrier stabilization and thrombin-induced barrier breakdown}, timestamp = {2010-12-14T18:20:48.000+0100}, title = {Role of Rac 1 and cAMP in endothelial barrier stabilization and thrombin-induced barrier breakdown}, url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19472214}, volume = 220, year = 2009 }