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This Article Full Text Full Text (PDF) All Versions of this Article: 296/3/F634    most recent 90232.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kirby, R. J. Articles by Arend, L. J. Search for Related Content PubMed PubMed Citation Articles by Kirby, R. J. Articles by Arend, L. J.

Dynamic regulation of sphingosine-1-phosphate homeostasis during development of mouse metanephric kidney

¹Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio; and ²Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York

Submitted 2 April 2008 ; accepted in final form 8 December 2008

Branching morphogenesis of the metanephric kidney is critically dependent on the delicate orchestration of diverse cellular processes including proliferation, apoptosis, migration, and differentiation. Sphingosine-1-phosphate (S1P) is a potent lipid mediator influencing many of these cellular events. We report increased expression and activity of both sphingosine kinases and S1P phosphatases during development of the mouse metanephric kidney from induction at embryonic day 11.5 to maturity. Sphingosine kinase activity exceeded S1P phosphatase activity in embryonic kidneys, resulting in a net accumulation of S1P, while kinase and phosphatase activities were similar in adult tissue, resulting in reduced S1P content. Sphingosine kinase expression was greater in the metanephric mesenchyme than in the ureteric bud, while the S1P phosphatase SPP2 was expressed at greater levels in the ureteric bud. Treatment of cultured embryonic kidneys with sphingosine kinase inhibitors resulted in a dose-dependent reduction of ureteric bud tip numbers and increased apoptosis. Exogenous S1P rescued kidneys from apoptosis induced by kinase inhibitors. Ureteric bud tip number was unaffected by exogenous S1P in kidneys treated with N,N-dimethylsphingosine, although tip number increased in those treated with D,L-threo-dihydrosphingosine. S1P₁ and S1P₂ were the predominant S1P receptors expressed in the embryonic kidney. S1P₁ expression increased during renal development while expression of S1P₂ decreased, and both receptors were expressed predominantly in the metanephric mesenchyme. These results demonstrate dynamic regulation of S1P homeostasis during renal morphogenesis and suggest that differential expression of S1P metabolic enzymes and receptors provides a novel mechanism contributing to the regulation of kidney development.

renal morphogenesis; sphingolipid; kinase; phosphatase; receptor