title: Synergy between sphingosine 1-phosphate and lipopolysaccharide signaling promotes an inflammatory, angiogenic and osteogenic response in human aortic valve interstitial cells.
abstract: Given that the bioactive lipid sphingosine 1-phosphate is involved in cardiovascular pathophysiology, and since lipid accumulation and inflammation are hallmarks of calcific aortic stenosis, the role of sphingosine 1-phosphate on the pro-inflammatory/pro-osteogenic pathways in human interstitial cells from aortic and pulmonary valves was investigated. Real-time PCR showed sphingosine 1-phosphate receptor expression in aortic valve interstitial cells. Exposure of cells to sphingosine 1-phosphate induced pro-inflammatory responses characterized by interleukin-6, interleukin-8, and cyclooxygenase-2 up-regulations, as observed by ELISA and Western blot. Strikingly, cell treatment with sphingosine 1-phosphate plus lipopolysaccharide resulted in the synergistic induction of cyclooxygenase-2, and intercellular adhesion molecule 1, as well as the secretion of prostaglandin E2, the soluble form of the intercellular adhesion molecule 1, and the pro-angiogenic factor vascular endothelial growth factor-A. Remarkably, the synergistic effect was significantly higher in aortic valve interstitial cells from stenotic than control valves, and was drastically lower in cells from pulmonary valves, which rarely undergo stenosis. siRNA and pharmacological analysis revealed the involvement of sphingosine 1-phosphate receptors 1/3 and Toll-like receptor-4, and downstream signaling through p38/MAPK, protein kinase C, and NF-κB. As regards pro-osteogenic pathways, sphingosine 1-phosphate induced calcium deposition and the expression of the calcification markers bone morphogenetic protein-2 and alkaline phosphatase, and enhanced the effect of lipopolysaccharide, an effect that was partially blocked by inhibition of sphingosine 1-phosphate receptors 3/2 signaling. In conclusion, the interplay between sphingosine 1-phosphate receptors and Toll-like receptor 4 signaling leads to a cooperative up-regulation of inflammatory, angiogenic, and osteogenic pathways in aortic valve interstitial cells that seems relevant to the pathogenesis of aortic stenosis and may allow the inception of new therapeutic approaches.
authors.affiliation: Instituto de Biología y Genética Molecular (CSIC-Universidad Valladolid), Valladolid, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Fernández-Pisonero
authors.affiliation: Cardiology Department, Instituto Ciencias del Corazón (ICICOR) Hospital Clínico Universitario, Valladolid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: López
authors.affiliation: Instituto de Biología y Genética Molecular (CSIC-Universidad Valladolid), Valladolid, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Onecha
authors.affiliation: Research Unit, Hospital Clínico Universitario, Valladolid, Spain.
authors.forename: Ana I
authors.initials: AI
authors.lastname: Dueñas
authors.affiliation: Instituto de Biología y Genética Molecular (CSIC-Universidad Valladolid), Valladolid, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Maeso
authors.affiliation: Instituto de Biología y Genética Molecular (CSIC-Universidad Valladolid), Valladolid, Spain.
authors.forename: Mariano Sánchez
authors.initials: MS
authors.lastname: Crespo
authors.affiliation: Cardiology Department, Instituto Ciencias del Corazón (ICICOR) Hospital Clínico Universitario, Valladolid, Spain.
authors.forename: José Alberto
authors.initials: JA
authors.lastname: San Román
authors.affiliation: Instituto de Biología y Genética Molecular (CSIC-Universidad Valladolid), Valladolid, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: García-Rodríguez
mesh_terms: D000368:Aged; D000469:Alkaline Phosphatase / Q000378:metabolism; D001021:Aortic Valve / Q000378:metabolism / Q000473:pathology*; D001024:Aortic Valve Stenosis / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D005260:Female; D006801:Humans; D007249:Inflammation / Q000378:metabolism / Q000473:pathology*; D018836:Inflammation Mediators / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000378:metabolism*; D008246:Lysophospholipids / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018919:Neovascularization, Physiologic; D010012:Osteogenesis; D010641:Phenotype; D049349:Receptors, Lysosphingolipid / Q000378:metabolism; D015398:Signal Transduction; D012995:Solubility; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism
chemical_list: D015415:Biomarkers; D055396:Bone Morphogenetic Protein 2; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D008246:Lysophospholipids; D049349:Receptors, Lysosphingolipid; D051197:Toll-Like Receptor 4; D018799:Intercellular Adhesion Molecule-1; C060506:sphingosine 1-phosphate; D000469:Alkaline Phosphatase; D013110:Sphingosine; D002118:Calcium