Digitoxin elicits anti-inflammatory and vasoprotective properties in endothelial cells: Therapeutic implications for the treatment of atherosclerosis?
Pro-inflammatory processes initiated in the endothelium represent a crucial step in the pathogenesis of inflammatory cardiovascular disease, such as atherosclerosis. Recent observations pointed to potential anti-inflammatory properties of the cardiac glycoside digitoxin. Therefore, the present study investigated potential anti-inflammatory and vasoprotective properties of digitoxin as well as the underlying signaling pathways affected in endothelial cells (EC). Digitoxin, employing therapeutical concentrations used in patients (3-30nM), potently inhibited the IL-1beta-induced expression of MCP-1 and VCAM-1 in EC and the capacity of corresponding cell culture supernatants on monocyte migration as well as monocyte adhesion to endothelial monolayers, respectively. Furthermore, digitoxin prevented the IL-1beta-induced activation of p44/42-MAPK and NF-kappaB without affecting activation of JNK and p38-MAPK. Inhibition of NF-kappaB signaling but not p44/42-MAPK mimicked the observed inhibitory effects of digitoxin on MCP-1 expression and monocyte migration. Moreover, digitoxin inhibited NF-kappaB signaling at the level of TAK-1/IKK. Additionally, digitoxin prevented TNF-alpha-induced apoptosis in EC accompanied by activation of Akt. Blockade of PI-3-kinase, activator of Akt, prevented the anti-apoptotic properties of digitoxin and impaired its inhibitory action on NF-kappaB signaling and MCP-1 expression. Finally, digitoxin activated endothelial NO-synthase, which was blocked by inhibition of PI-3-kinase, Ca(2+)/Calmodulin-dependent-proteinkinase-II and chelation of intracellular calcium. Digitoxin elicits anti-inflammatory and vasoprotective properties by blocking NF-kappaB and activating PI-3-kinase/Akt signaling as well as Ca(2+)/Calmodulin-dependent-proteinkinase-II in EC. These observations indicate a potential therapeutical application of digitoxin in the treatment of cardiovascular diseases, such as atherosclerosis.
Jagielska
Joanna
J
Clinic of Cardiology and Angiology, Hannover Medical School, Carl-Neuberg-Str. 01, 30625 Hannover, Germany.
Salguero
Gustavo
G
Schieffer
Bernhard
B
Bavendiek
Udo
U
D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D050197:Atherosclerosis / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D004074:Digitoxin / Q000494:pharmacology*; D004077:Digoxin / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D051550:I-kappa B Kinase / Q000037:antagonists & inhibitors; D053583:Interleukin-1beta / Q000037:antagonists & inhibitors / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis
D000893:Anti-Inflammatory Agents; D053583:Interleukin-1beta; D016328:NF-kappa B; D019010:Vascular Cell Adhesion Molecule-1; D004077:Digoxin; D004074:Digitoxin; D052250:Nitric Oxide Synthase Type III; D051550:I-kappa B Kinase; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3