VEGF-A/VEGFR-2 signaling leading to cAMP response element-binding protein phosphorylation is a shared pathway underlying the protective effect of preconditioning on neurons and endothelial cells.
Preconditioning protects endothelial cells as well as neurons from ischemic injury. In 7-d-old rat pups, ligating the carotid artery 1 h before hypoxia damaged the ipsilateral cerebral hemisphere; in contrast, ligating the artery 24 h before hypoxia provided complete neuroprotection. The protective effect of the 24 h artery ligation preconditioning model requires the activation of cAMP response element-binding protein (CREB). We tested the hypothesis that vascular endothelial growth factor (VEGF)-A/VEGF receptor-2 (VEGFR-2) signaling that leads to CREB activation is the shared pathway underlying the protective effect of preconditioning in neurons and endothelial cells. VEGF-A, VEGFR-1, or VEGFR-2 was inhibited by antisense oligodeoxynucleotides (ODNs) in vivo and by a VEGF-A neutralizing antibody or VEGFR-2 inhibitor in vitro. CREB phosphorylation (pCREB) and VEGF-A and VEGFR-2 expression were increased and colocalized in vascular endothelial cells and neurons in the ipsilateral cerebral cortex 24 h after ligation. The antisense ODN blockades of VEGF-A and VEGFR-2 decreased pCREB and reduced the protection of 24 h ligation preconditioning. Furthermore, oxygen-glucose deprivation (OGD) preconditioning upregulated VEGF-A, VEGFR-2, and pCREB levels and protected immortalized H19-7 neuronal cells and b.End3 vascular endothelial cells against 24 h OGD cell death. Blocking VEGF-A or VEGFR-2 reduced CREB activation and the effects of OGD preconditioning in neuronal cells and endothelial cells. Transfecting a serine-133 phosphorylation mutant CREB also inhibited the protective effect of OGD preconditioning. We conclude that VEGF-A/VEGFR-2 signaling leading to CREB phosphorylation is the shared pathway underlying the preconditioning-induced protective effect in neurons and vascular endothelial cells in the developing brain.
Lee
Hsueh-Te
HT
Department of Pediatrics, Institute of Clinical Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
Chang
Ying-Chao
YC
Tu
Yi-Fang
YF
Huang
Chao-Ching
CC
D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control; D002461:Cell Line, Transformed; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism* / Q000502:physiology; D042783:Endothelial Cells / Q000378:metabolism / Q000502:physiology*; D005947:Glucose / Q000502:physiology; D006801:Humans; D019194:Ischemic Preconditioning / Q000379:methods; D008297:Male; D051379:Mice; D009434:Neural Pathways / Q000378:metabolism / Q000502:physiology*; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D010100:Oxygen / Q000502:physiology; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000502:physiology*
D017362:Cyclic AMP Response Element-Binding Protein; D042461:Vascular Endothelial Growth Factor A; D040301:Vascular Endothelial Growth Factor Receptor-2; D005947:Glucose; D010100:Oxygen