Different modes of endothelial-smooth muscle cell interaction elicit differential β-catenin phosphorylations and endothelial functions.
β-Catenin phosphorylation plays important roles in modulating its functions, but the effects of different phosphorylated forms of β-catenin in response to heterocellular interaction are unclear. Here we investigated whether distinct modes of phosphorylation on β-catenin could be triggered through heterocellular interactions between endothelial cells (ECs) and smooth muscle cells (SMCs), and the consequent modulation of EC functions. ECs were cocultured with SMCs to initiate direct contact and paracrine interaction. EC-SMC coculture induced EC β-catenin phosphorylations simultaneously at tyrosine 142 (Tyr142) and serine 45/threonine 41 (Ser45/Thr41) at the cytoplasm/nuclei and the membrane, respectively. Treating ECs with SMC-conditional medium induced β-catenin phosphorylation only at Ser45/Thr41. These findings indicate that different phosphorylation effects of EC-SMC coculture were induced through heterocellular direct contact and paracrine effects, respectively. Using specific blocking peptides, antagonists, and siRNAs, we found that the β-catenin Tyr142-phosphorylation was mediated by connexin 43/Fer and that the β-catenin Ser45/Thr41-phosphorylation was mediated by SMC-released bone morphogenetic proteins through VE-cadherin and bone morphogenetic protein receptor-II/Smad5. Transfecting ECs with β-catenin-Tyr142 or -Ser45 mutants showed that these two phosphorylated forms of β-catenin modulate differential EC function: The Tyr142-phosphorylated β-catenin stimulates vascular cell-adhesion molecule-1 expression to increase EC-monocytic adhesion, but the Ser45/Thr41-phosphorylated β-catenin attenuates VE-cadherin-dependent junction structures to increase EC permeability. Our findings provide new insights into the understanding of regulatory complexities of distinct modes of β-catenin phosphorylations under EC-SMC interactions and suggest that different phosphorylated forms of β-catenin play important roles in modulating vascular pathophysiology through different heterocellular interactions.
Biophotonics and Molecular Imaging Research Center, National Yang-Ming University, Taipei 11221, Taiwan.
Shun-Fu
SF
Chang
Li-Jing
LJ
Chen
Pei-Ling
PL
Lee
Ding-Yu
DY
Lee
Shu
S
Chien
Jeng-Jiann
JJ
Chiu
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D052006:Bone Morphogenetic Protein Receptors, Type II / Q000378:metabolism; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism; D002417:Cattle; D002448:Cell Adhesion; D002450:Cell Communication; D002451:Cell Compartmentation; D002463:Cell Membrane Permeability; D018031:Connexin 43 / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology* / Q000378:metabolism*; D008954:Models, Biological; D009000:Monocytes / Q000166:cytology / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000166:cytology* / Q000378:metabolism; D019899:Paracrine Communication; D010766:Phosphorylation; D010769:Phosphothreonine / Q000378:metabolism; D019000:Phosphotyrosine / Q000378:metabolism; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D059748:Proteolysis; D051902:Smad5 Protein / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism*; D000099152:Cadherin 5
D015703:Antigens, CD; D052006:Bone Morphogenetic Protein Receptors, Type II; D019485:Bone Morphogenetic Proteins; D015820:Cadherins; D018031:Connexin 43; D010769:Phosphothreonine; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases; D051902:Smad5 Protein; D025801:Ubiquitin; D019010:Vascular Cell Adhesion Molecule-1; D051176:beta Catenin; D000099152:Cadherin 5; C497797:SMAD5 protein, human
endothelial permeability; inflammation