title: Downregulation of sphingosine 1-phosphate (S1P) receptor 1 by dexamethasone inhibits S1P-induced mesangial cell migration.
abstract: Sphingosine 1-phosphate (S1P) is generated by sphingosine kinase (SK)-1 and -2 and acts mainly as an extracellular ligand at five specific receptors, denoted S1P1-5. After activation, S1P receptors regulate important processes in the progression of renal diseases, such as mesangial cell migration and survival. Previously, we showed that dexamethasone enhances SK-1 activity and S1P formation, which protected mesangial cells from stress-induced apoptosis. Here we demonstrate that dexamethasone treatment lowered S1P1 mRNA and protein expression levels in rat mesangial cells. This effect was abolished in the presence of the glucocorticoid receptor antagonist RU-486. In addition, in vivo studies showed that dexamethasone downregulated S1P1 expression in glomeruli isolated from mice treated with dexamethasone (10 mg/kg body weight). Functionally, we identified S1P1 as a key player mediating S1P-induced mesangial cell migration. We show that dexamethasone treatment significantly lowered S1P-induced migration of mesangial cells, which was again reversed in the presence of RU-486. In summary, we suggest that dexamethasone inhibits S1P-induced mesangial cell migration via downregulation of S1P1. Overall, these results demonstrate that dexamethasone has functional important effects on sphingolipid metabolism and action in renal mesangial cells.
authors.forename: Alexander
authors.initials: A
authors.lastname: Koch
authors.forename: Manuel
authors.initials: M
authors.lastname: Jäger
authors.forename: Anja
authors.initials: A
authors.lastname: Völzke
authors.forename: Georgios
authors.initials: G
authors.lastname: Grammatikos
authors.forename: Dagmar Meyer
authors.initials: DM
authors.lastname: Zu Heringdorf
authors.forename: Andrea
authors.initials: A
authors.lastname: Huwiler
authors.forename: Josef
authors.initials: J
authors.lastname: Pfeilschifter
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology*; D015536:Down-Regulation; D007668:Kidney / Q000166:cytology; D008246:Lysophospholipids / Q000494:pharmacology*; D050527:Mesangial Cells / Q000166:cytology* / Q000187:drug effects*; D051379:Mice; D051381:Rats; D049349:Receptors, Lysosphingolipid / Q000235:genetics / Q000378:metabolism*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D008246:Lysophospholipids; D049349:Receptors, Lysosphingolipid; C060506:sphingosine 1-phosphate; D003907:Dexamethasone; D013110:Sphingosine