Abstract
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.
Publication types
-
Research Support, N.I.H., Extramural
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Annexin A2 / genetics
-
Annexin A2 / metabolism*
-
Antigens, CD / genetics
-
Antigens, CD / metabolism
-
Cadherins / genetics
-
Cadherins / metabolism
-
Cytosol / metabolism*
-
Endothelial Cells / cytology
-
Endothelial Cells / metabolism*
-
Enzyme Activation / physiology
-
Gene Knockdown Techniques
-
HEK293 Cells
-
Humans
-
Intercellular Junctions / genetics
-
Intercellular Junctions / metabolism*
-
Lysophospholipids / genetics
-
Lysophospholipids / metabolism
-
Mitogen-Activated Protein Kinase 1 / genetics
-
Mitogen-Activated Protein Kinase 1 / metabolism
-
Mitogen-Activated Protein Kinase 3 / genetics
-
Mitogen-Activated Protein Kinase 3 / metabolism
-
Neovascularization, Physiologic / physiology*
-
Protein Transport / physiology
-
Proto-Oncogene Proteins c-akt / genetics
-
Proto-Oncogene Proteins c-akt / metabolism*
-
Sphingosine / analogs & derivatives
-
Sphingosine / genetics
-
Sphingosine / metabolism
Substances
-
ANXA2 protein, human
-
Annexin A2
-
Antigens, CD
-
Cadherins
-
Lysophospholipids
-
cadherin 5
-
sphingosine 1-phosphate
-
Proto-Oncogene Proteins c-akt
-
MAPK1 protein, human
-
Mitogen-Activated Protein Kinase 1
-
Mitogen-Activated Protein Kinase 3
-
Sphingosine