Annexin 2 regulates endothelial morphogenesis by controlling AKT activation and junctional integrity.
Sprouting angiogenesis is a multistep process that involves endothelial cell activation, basement membrane degradation, proliferation, lumen formation, and stabilization. In this study, we identified annexin 2 as a regulator of endothelial morphogenesis using a three-dimensional in vitro model where sprouting angiogenesis was driven by sphingosine 1-phosphate and angiogenic growth factors. We observed that sphingosine 1-phosphate triggered annexin 2 translocation from the cytosol to the plasma membrane and its association with vascular endothelial (VE)-cadherin. In addition, annexin 2 depletion attenuated Akt activation, which was associated with increased phosphorylation of VE-cadherin and endothelial barrier leakage. Disrupting homotypic VE-cadherin interactions with EGTA, antibodies to the extracellular domain of VE-cadherin, or gene silencing all resulted in decreased Akt (but not Erk1/2) activation. Furthermore, expression of constitutively active Akt restored reduced endothelial sprouting responses observed with annexin 2 and VE-cadherin knockdown. Collectively, we report that annexin 2 regulates endothelial morphogenesis through an adherens junction-mediated pathway upstream of Akt.
Su
Shih-Chi
SC
Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, Texas 77843-1114, USA.
Maxwell
Steve A
SA
Bayless
Kayla J
KJ
D017306:Annexin A2 / Q000235:genetics / Q000378:metabolism*; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism*; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D004789:Enzyme Activation / Q000502:physiology; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D006801:Humans; D007365:Intercellular Junctions / Q000235:genetics / Q000378:metabolism*; D008246:Lysophospholipids / Q000235:genetics / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000502:physiology*; D021381:Protein Transport / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D013110:Sphingosine / Q000031:analogs & derivatives / Q000235:genetics / Q000378:metabolism; D000099152:Cadherin 5
D017306:Annexin A2; D015703:Antigens, CD; D015820:Cadherins; D008246:Lysophospholipids; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D051057:Proto-Oncogene Proteins c-akt; D013110:Sphingosine; D000099152:Cadherin 5; C472822:ANXA2 protein, human; C060506:sphingosine 1-phosphate; C535150:MAPK1 protein, human