title: A role for sphingosine kinase 1 in dextran sulfate sodium-induced colitis.
abstract: The bioactive lipid sphingosine-1-phosphate (S1P) is emerging as an important mediator of immune and inflammatory responses. S1P formation is catalyzed by sphingosine kinase (SK), of which the SK1 isoenzyme is activated by tumor necrosis alpha (TNF-alpha). SK1 has been shown to be required for mediating TNF-alpha inflammatory responses in cells, including induction of cyclooxygenase 2 (COX-2). Because TNF-alpha and COX-2 are increased in patients with inflammatory bowel disease (IBD), we investigated the role of SK1 in a murine model of colitis. SK1(-/-) mice treated with dextran sulfate sodium (DSS) had significantly less blood loss, weight loss, colon shortening, colon histological damage, and splenomegaly than did wild-type (WT) mice. In addition, SK1(-/-) mice had no systemic inflammatory response. Moreover, WT but not SK1(-/-) mice treated with dextran sulfate sodium had significant increases in blood S1P levels, colon SK1 message and activity, and colon neutrophilic infiltrate. Unlike WT mice, SK1(-/-) mice failed to show colonic COX-2 induction despite an exaggerated TNF-alpha response; thus implicating for the first time SK1 in TNF-alpha-mediated COX-2 induction in vivo. Inhibition of SK1 may prove to be a valuable therapeutic target by inhibiting systemic and local inflammation in IBD.
authors.affiliation: Department of Medicine, Medical University of South Carolina, 114 Doughty St., MSC 779, Charleston, SC 29425, USA.
authors.forename: Ashley J
authors.initials: AJ
authors.lastname: Snider
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Kawamori
authors.forename: Sarah G
authors.initials: SG
authors.lastname: Bradshaw
authors.forename: K Alexa
authors.initials: KA
authors.lastname: Orr
authors.forename: Gary S
authors.initials: GS
authors.lastname: Gilkeson
authors.forename: Yusuf A
authors.initials: YA
authors.lastname: Hannun
authors.forename: Lina M
authors.initials: LM
authors.lastname: Obeid
mesh_terms: D000818:Animals; D001835:Body Weight; D003092:Colitis / Q000139:chemically induced* / Q000378:metabolism*; D003093:Colitis, Ulcerative / Q000378:metabolism / Q000473:pathology; D003106:Colon / Q000473:pathology; D051546:Cyclooxygenase 2 / Q000378:metabolism; D016264:Dextran Sulfate / Q000633:toxicity*; D004912:Erythrocytes / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D008246:Lysophospholipids / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009929:Organ Size; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*; D013110:Sphingosine / Q000031:analogs & derivatives / Q000378:metabolism; D013154:Spleen / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D000099157:Sphingosine Kinase
chemical_list: D051546:Cyclooxygenase 2; D016264:Dextran Sulfate; D008246:Lysophospholipids; D017853:Phosphotransferases (Alcohol Group Acceptor); D013110:Sphingosine; D014409:Tumor Necrosis Factor-alpha; D000099157:Sphingosine Kinase; C060506:sphingosine 1-phosphate; C077623:Ptgs2 protein, mouse