title: VEGF-mediated PI3K class IA and PKC signaling in cardiomyogenesis and vasculogenesis of mouse embryonic stem cells.
abstract: VEGF-, phosphoinositide 3-kinase (PI3K)- and protein kinase C (PKC)-regulated signaling in cardiac and vascular differentiation was investigated in mouse ES cells and in ES cell-derived Flk-1⁺ cardiovascular progenitor cells. Inhibition of PI3K by wortmannin and LY294002, disruption of PI3K catalytic subunits p110α and p110δ using short hairpin RNA (shRNA), or inhibition of p110α with compound 15e and of p110δ with IC-87114 impaired cardiac and vascular differentiation. By contrast, TGX-221, an inhibitor of p110β, and shRNA knockdown of p110β were without significant effects. Antagonists of the PKC family, i.e. bisindolylmaleimide-1 (BIM-1), GÖ 6976 (targeting PKCα/βII) and rottlerin (targeting PKCδ) abolished vasculogenesis, but not cardiomyogenesis. Inhibition of Akt blunted cardiac as well as vascular differentiation. VEGF induced phosphorylation of PKCα/βII and PKCδ but not PKCζ. This was abolished by PI3K inhibitors and the VEGFR-2 antagonist SU5614. Furthermore, phosphorylation of Akt and phosphoinositide-dependent kinase-1 (PDK1) was blunted upon inhibition of PI3K, but not upon inhibition of PKC by BIM-1, suggesting that activation of Akt and PDK1 by VEGF required PI3K but not PKC. In summary, we demonstrate that PI3K catalytic subunits p110α and p110δ are central to cardiovasculogenesis of ES cells. Akt downstream of PI3K is involved in both cardiomyogenesis and vasculogenesis, whereas PKC is involved only in vasculogenesis.
authors.affiliation: Department of Internal Medicine I, Cardiology Division, Friedrich Schiller University, 07743 Jena, Germany.
authors.forename: Mohamed M
authors.initials: MM
authors.lastname: Bekhite
authors.forename: Andreas
authors.initials: A
authors.lastname: Finkensieper
authors.forename: Stephanie
authors.initials: S
authors.lastname: Binas
authors.forename: Jörg
authors.initials: J
authors.lastname: Müller
authors.forename: Reinhard
authors.initials: R
authors.lastname: Wetzker
authors.forename: Hans-Reiner
authors.initials: HR
authors.lastname: Figulla
authors.forename: Heinrich
authors.initials: H
authors.lastname: Sauer
authors.forename: Maria
authors.initials: M
authors.lastname: Wartenberg
mesh_terms: D000818:Animals; D020134:Catalytic Domain; D002454:Cell Differentiation; D002460:Cell Line; D002867:Chromones / Q000494:pharmacology; D058543:Class Ia Phosphatidylinositol 3-Kinase / Q000235:genetics / Q000378:metabolism*; D058732:Embryoid Bodies / Q000166:cytology* / Q000187:drug effects; D004789:Enzyme Activation; D051379:Mice; D009025:Morpholines / Q000494:pharmacology; D024510:Muscle Development; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism; D018919:Neovascularization, Physiologic; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034622:RNA Interference; D015398:Signal Transduction; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*
chemical_list: D002867:Chromones; D009025:Morpholines; D000081082:Phosphoinositide-3 Kinase Inhibitors; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D058543:Class Ia Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; D011493:Protein Kinase C