Transforming growth factor-β-activated kinase 1 regulates angiogenesis via AMP-activated protein kinase-α1 and redox balance in endothelial cells.
OBJECTIVE
Transforming growth factor-β-activated kinase 1 (TAK1) is a mitogen-activated protein 3-kinase and an AMP-activated protein kinase (AMPK) kinase in some cell types. Although TAK1(-/-) mice display defects in developmental vasculogenesis, the role of TAK1 in endothelial cells has not been investigated in detail.


RESULTS
TAK1 downregulation (small interfering RNA) in human endothelial cells attenuated proliferation without inducing apoptosis and diminished endothelial cell migration, as well as tube formation. Cytokine- and vascular endothelial growth factor (VEGF)-induced endothelial cell sprouting in a modified spheroid assay were abrogated by TAK1 downregulation. Moreover, VEGF-induced endothelial sprouting was impaired in aortic rings from mice lacking TAK1 in endothelial cells (TAK(ΔEC)). TAK1 inhibition and downregulation also inhibited VEGF-stimulated phosphorylation of several kinases, including AMPK. Proteomic analyses revealed that superoxide dismutase 2 (SOD2) expression was reduced in TAK1-deficient endothelial cells, resulting in attenuated hydrogen peroxide production but increased mitochondrial superoxide production. Endothelial cell SOD2 expression was also attenuated by AMPK inhibition and in endothelial cells from AMPKα1(-/-) mice but was unaffected by inhibitors of c-Jun N-terminal kinase, p38, extracellular signal-regulated kinase 1/2, or phosphatidylinositol 3-kinase/Akt. Moreover, the impaired endothelial sprouting from TAK(ΔEC) aortic rings was abrogated in the presence of polyethylene glycol-SOD, and tube formation was normalized by the overexpression of SOD2. A similar rescue of angiogenesis was observed in polyethylene glycol-SOD-treated aortic rings from mice with endothelial cell-specific deletion of the AMPKα1.


CONCLUSIONS
These results establish TAK1 as an AMPKα1 kinase that regulates vascular endothelial growth factor-induced and cytokine-induced angiogenesis by modulating SOD2 expression and the superoxide anion:hydrogen peroxide balance.
From the Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Frankfurt, Germany and DZHK (German Centre for Cardiovascular Research) partner site Rhine-Main (N.Z., R.A.M., T.F., R.P., E.B., I.F., B.F.); and Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany (B.S., N.W.).
Nina
N
Zippel
Randa Abdel
RA
Malik
Timo
T
Frömel
Rüdiger
R
Popp
Elke
E
Bess
Boris
B
Strilic
Nina
N
Wettschureck
Ingrid
I
Fleming
Beate
B
Fisslthaler
D055372:AMP-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002465:Cell Movement; D049109:Cell Proliferation; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D061307:Human Umbilical Vein Endothelial Cells / Q000201:enzymology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism; D018919:Neovascularization, Physiologic; D010084:Oxidation-Reduction; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D011973:Receptors, LDL / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D000072105:Superoxide Dismutase-1; D013997:Time Factors; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D000099151:MAP Kinase Kinase Kinase 7; D000099156:Superoxide Dismutase 2
D055372:AMP-Activated Protein Kinases; D000975:Antioxidants; D006861:Hydrogen Peroxide; D053583:Interleukin-1beta; D020930:MAP Kinase Kinase Kinases; D047428:Protein Kinase Inhibitors; D011973:Receptors, LDL; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D042461:Vascular Endothelial Growth Factor A; D000099151:MAP Kinase Kinase Kinase 7; D000099156:Superoxide Dismutase 2; C000606290:SOD1 protein, human; C000606291:Sod1 protein, mouse; C548179:Prkaa1 protein, mouse; C526180:PRKAA1 protein, human
AMPK kinase; MAP kinase kinase kinase 7; angiogenesis modulators; redox