title: CD40-dependent activation of phosphatidylinositol 3-kinase/Akt pathway mediates endothelial cell survival and in vitro angiogenesis.
abstract: CD40 has been involved in tumor and inflammatory neoangiogenesis. In this study we determined that stimulation of endothelial CD40 with sCD154 induced resistance to apoptosis and in vitro vessel-like formation by human microvascular endothelial cells (HMEC). These effects were determined to be mediated by CD40-dependent signaling because they were inhibited by a soluble CD40-muIg fusion protein. Moreover, apoptosis of HMEC was associated with an impairment of Akt phosphorylation, which was restored by stimulation with sCD154. The anti-apoptotic effect as well as in vitro vessel-like formation and Akt phosphorylation were inhibited by treatment of HMEC with two unrelated pharmacological inhibitors of phosphatidylinositol 3-kinase (PI3K), wortmannin and LY294002. CD40 stimulation induced a rapid increase in Akt enzymatic activity that was not prevented by cycloheximide, an inhibitor of protein synthesis. The enhanced Akt activity induced by stimulation of endothelial CD40 was temporarily correlated with the association of CD40 with TRAF6, c-Cbl, and the p85 subunit of PI3K. Expression of negative-dominant Akt inhibited the activation of endogenous Akt through CD40 stimulation, despite the observation that association of CD40 with TRAF6, c-Cbl, and PI3K was intact. The defective activation of Akt abrogated not only the anti-apoptotic effect of CD40 stimulation but also the proliferative response, the enhanced motility, and the in vitro formation of vessel-like tubular structures by CD40-stimulated HMEC. In conclusion, these results suggest that endothelial CD40, through activation of the PI3K/Akt signaling pathway, regulates cell survival, proliferation, migration, and vessel-like structure formation, all steps considered critical for angiogenesis.
authors.affiliation: Cattedra di Nefrologia, Dipartimento di Medicina Interna, Università di Torino, and Centro Ricerca Medicina Sperimentale (CeRMS), Torino 10126, Italy.
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Deregibus
authors.forename: Stefano
authors.initials: S
authors.lastname: Buttiglieri
authors.forename: Simona
authors.initials: S
authors.lastname: Russo
authors.forename: Benedetta
authors.initials: B
authors.lastname: Bussolati
authors.forename: Giovanni
authors.initials: G
authors.lastname: Camussi
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D017209:Apoptosis; D015153:Blotting, Western; D001973:Bromodeoxyuridine / Q000494:pharmacology; D019013:CD40 Antigens / Q000378:metabolism*; D023201:CD40 Ligand / Q000378:metabolism; D002455:Cell Division; D002465:Cell Movement; D002470:Cell Survival; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D053938:DNA Fragmentation; D004591:Electrophoresis, Polyacrylamide Gel; D004730:Endothelium, Vascular / Q000166:cytology / Q000473:pathology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D006801:Humans; D009025:Morpholines / Q000494:pharmacology; D009389:Neovascularization, Pathologic; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D050721:Proto-Oncogene Proteins c-cbl; D015398:Signal Transduction; D048029:TNF Receptor-Associated Factor 6; D013997:Time Factors; D014162:Transfection; D044767:Ubiquitin-Protein Ligases; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D019013:CD40 Antigens; D002867:Chromones; D004791:Enzyme Inhibitors; D009025:Morpholines; D011500:Protein Synthesis Inhibitors; D011506:Proteins; D011518:Proto-Oncogene Proteins; D048029:TNF Receptor-Associated Factor 6; D023201:CD40 Ligand; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D003513:Cycloheximide; D050721:Proto-Oncogene Proteins c-cbl; D044767:Ubiquitin-Protein Ligases; D019869:Phosphatidylinositol 3-Kinases; C067419:CBL protein, human; D001973:Bromodeoxyuridine; D000077191:Wortmannin