Angiopoietin-1 induces neurite outgrowth of PC12 cells in a Tie2-independent, beta1-integrin-dependent manner.
Overexpression of angiopoietin (Ang) 1 in the brain results in increased vascularization and altered neuronal dendrite configuration. We hypothesized that Ang1 acts directly on neurons inducing neurite outgrowth. We stimulated PC12 cells with Ang1 and observed outgrowth levels comparable to nerve growth factor (NGF). Western blotting and RT-PCR demonstrated the absence of the Ang1 receptor, Tie2 and the presence of beta1-integrin. Downstream of beta1-integrin, Ang1 stimulation led to a approximately 2.6 fold increase in focal adhesion kinase (FAK) phosphorylation and no change in the activation of mitogen-activated protein kinase (MAPK) nor c-Jun N-terminal kinase (JNK). Conversely, NGF stimulation had no effect on FAK phosphorylation but led to a approximately 3.1 and approximately 2 fold increase in phosphorylation of MAPK and JNK. Ang1, but not NGF-mediated outgrowth was attenuated following functional inhibition of beta1-integrin and FAK, and Wortmannin inhibited neurite outgrowth mediated by both. Our results suggest that Ang1 induces neurite outgrowth in PC12 cells in a Tie2-independent, beta1-integrin-FAK-PI3K-Akt-dependent manner and that NGF and Ang1 mediate neurite outgrowth via two independent signaling mechanisms.
Chen
Xinyu
X
Department of Dermatology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
Fu
Wen
W
Tung
Christie E
CE
Ward
Nicole L
NL
D042683:Angiopoietin-1 / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D051417:Focal Adhesion Kinase 1 / Q000187:drug effects / Q000378:metabolism; D039641:Integrin beta Chains / Q000187:drug effects / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D020932:Nerve Growth Factor / Q000378:metabolism / Q000494:pharmacology; D016501:Neurites / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D055495:Neurogenesis / Q000187:drug effects / Q000502:physiology; D016716:PC12 Cells; D019869:Phosphatidylinositol 3-Kinases / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D042787:Receptor, TIE-2 / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
D042683:Angiopoietin-1; C467629:Angpt1 protein, rat; D004791:Enzyme Inhibitors; D039641:Integrin beta Chains; D020932:Nerve Growth Factor; D019869:Phosphatidylinositol 3-Kinases; D042787:Receptor, TIE-2; D051417:Focal Adhesion Kinase 1; C496052:Ptk2 protein, rat; D051057:Proto-Oncogene Proteins c-akt