Sphingosine-1-phosphate modulates expression of vascular endothelial growth factor in human articular chondrocytes: a possible new role in arthritis.
OBJECTIVE
Although sphingosine-1-phosphate (S1P) is suggested to have an important role in arthritis, its function in chondrocytes remains unknown. In contrast, vascular endothelial growth factor (VEGF) has been speculated to contribute to the pathogenesis of osteoarthritis (OA), most likely by regulating angiogenesis. We here investigated the in vitro effect of S1P on VEGF expression in human articular chondrocytes from OA patients.


METHODS
Human articular cartilage samples were obtained from patients with OA under informed consent. Chondrocytes were isolated by an enzymatic procedure, grown in monolayer culture, and then stimulated with S1P in the presence or absence of mitogen-activated protein kinase (MAPK) inhibitors or the Gi protein inhibitor pertussis toxin (PTX). VEGF expression and secretion in culture supernatants were analyzed using real-time polymerase chain reaction and enzyme-linked immunosorbent assay.


RESULTS
Although S1P did not enhance basal secretion of matrix metalloproteinase (MMP)-1 and MMP-13, it stimulated VEGF expression in human articular chondrocytes, both at the messenger RNA and protein levels. MAPK inhibitors SB203580 and PD98059 were not effective at suppressing VEGF induction; rather, blocking extracellular signal-regulated kinase (ERK) MAPK enhanced VEGF expression. The Gi protein inhibitor PTX partially attenuated S1P-induced VEGF secretion.


CONCLUSIONS
Our results suggest that S1P may contribute to the regulation of VEGF expression in human chondrocytes. S1P may therefore play a unique role in the pathophysiology of OA by regulating VEGF expression in chondrocytes.
Department of Biochemistry, St. Marianna University School of Medicine, Kanagawa, Japan. k_msk@mac.com
Kayo
K
Masuko
Minako
M
Murata
Moroe
M
Beppu
Hiroshi
H
Nakamura
Tomohiro
T
Kato
Kazuo
K
Yudoh
D000368:Aged; D002358:Cartilage, Articular / Q000166:cytology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D000068876:Fingolimod Hydrochloride; D005419:Flavonoids / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007166:Immunosuppressive Agents / Q000494:pharmacology; D008246:Lysophospholipids / Q000494:pharmacology*; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D010003:Osteoarthritis / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism*; D037342:Pertussis Toxin / Q000494:pharmacology; D011409:Propylene Glycols / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics* / Q000378:metabolism*
D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D007166:Immunosuppressive Agents; D008246:Lysophospholipids; D011409:Propylene Glycols; D011725:Pyridines; D012333:RNA, Messenger; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C060506:sphingosine 1-phosphate; D037342:Pertussis Toxin; D020928:Mitogen-Activated Protein Kinases; D000068876:Fingolimod Hydrochloride; D013110:Sphingosine; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one