Adenosine regulates the proinflammatory signaling function of thrombin in endothelial cells.
The plasma level of the regulatory metabolite adenosine increases during the activation of coagulation and inflammation. Here we investigated the effect of adenosine on modulation of thrombin-mediated proinflammatory responses in HUVECs. We found that adenosine inhibits the barrier-disruptive effect of thrombin in HUVECs by a concentration-dependent manner. Analysis of cell surface expression of adenosine receptors revealed that A2A and A2B are expressed at the highest level among the four receptor subtypes (A2B  > A2A  > A1  > A3 ) on HUVECs. The barrier-protective effect of adenosine in response to thrombin was recapitulated by the A2A specific agonist, CGS 21680, and abrogated both by the siRNA knockdown of the A2A receptor and by the A2A -specific antagonists, ZM-241385 and SCH-58261. The thrombin-induced RhoA activation and its membrane translocation were both inhibited by adenosine in a cAMP-dependent manner, providing a molecular mechanism through which adenosine exerts a barrier-protective function. Adenosine also inhibited thrombin-mediated activation of NF-κB and decreased adhesion of monocytic THP-1 cells to stimulated HUVECs via down-regulation of expression of cell surface adhesion molecules, VCAM-1, ICAM-1, and E-selectin. Moreover, adenosine inhibited thrombin-induced elevated expression of proinflammatory cytokines, IL-6 and HMGB-1; and chemokines, MCP-1, CXCL-1, and CXCL-3. Taken together, these results suggest that adenosine may inhibit thrombin-mediated proinflammatory signaling responses, thereby protecting the endothelium from injury during activation of coagulation and inflammation.
Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri.
Seyed Mahdi
SM
Hassanian
Peyman
P
Dinarvand
Alireza R
AR
Rezaie
D000241:Adenosine / Q000378:metabolism* / Q000494:pharmacology; D058908:Adenosine A2 Receptor Agonists / Q000378:metabolism* / Q000494:pharmacology; D058917:Adenosine A2 Receptor Antagonists / Q000494:pharmacology; D001777:Blood Coagulation / Q000187:drug effects; D002199:Capillary Permeability; D002448:Cell Adhesion; D002478:Cells, Cultured; D018920:Coculture Techniques; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D019040:E-Selectin / Q000378:metabolism; D004789:Enzyme Activation; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000276:immunology / Q000378:metabolism*; D018836:Inflammation Mediators / Q000378:metabolism*; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D021381:Protein Transport; D034622:RNA Interference; D043705:Receptor, Adenosine A2A / Q000235:genetics / Q000378:metabolism; D043704:Receptor, Adenosine A2B / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013917:Thrombin / Q000378:metabolism* / Q000494:pharmacology; D014162:Transfection; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
D058908:Adenosine A2 Receptor Agonists; D058917:Adenosine A2 Receptor Antagonists; D019040:E-Selectin; C573420:ICAM1 protein, human; D018836:Inflammation Mediators; D016328:NF-kappa B; D043705:Receptor, Adenosine A2A; D043704:Receptor, Adenosine A2B; C546936:SELE protein, human; D019010:Vascular Cell Adhesion Molecule-1; C066737:RHOA protein, human; D018799:Intercellular Adhesion Molecule-1; D000242:Cyclic AMP; D013917:Thrombin; D020742:rhoA GTP-Binding Protein; D000241:Adenosine