title: Sphingosine kinase 1 knockdown reduces insulin synthesis and secretion in a rat insulinoma cell line.
abstract: To evaluate the role of sphingosine kinase 1 (SphK1) in insulin secretion, we used stable transfection to knock down the expression of the Sphk1 gene in the rat insulinoma INS-1 832/13 cell line. Cell lines with lowered Sphk1 mRNA expression and SphK1 enzyme activity (SK11 and SK14) exhibited lowered glucose- and 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid (BCH) plus glutamine-stimulated insulin release and low insulin content associated with decreases in the mRNA of the insulin 1 gene. Overexpression of the rat or human Sphk1 cDNA restored insulin secretion and total insulin content in the SK11 cell line, but not in the SK14 cell line. The Sphk1 cDNA-transfected SK14 cell line expressed significantly less SphK1 activity than the Sphk1 cDNA-transfected SK11 cells suggesting that the shRNA targeting SK14 was more effective in silencing the exogenous rat Sphk1 mRNA. The results indicate that SphK1 activity is important for insulin synthesis and secretion.
authors.affiliation: Childrens Diabetes Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, United States.
authors.forename: N M
authors.initials: NM
authors.lastname: Hasan
authors.forename: M J
authors.initials: MJ
authors.lastname: Longacre
authors.forename: S W
authors.initials: SW
authors.lastname: Stoker
authors.forename: M A
authors.initials: MA
authors.lastname: Kendrick
authors.forename: N R
authors.initials: NR
authors.lastname: Druckenbrod
authors.forename: S G
authors.initials: SG
authors.lastname: Laychock
authors.forename: L D
authors.initials: LD
authors.lastname: Mastrandrea
authors.forename: M J
authors.initials: MJ
authors.lastname: MacDonald
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000494:pharmacology; D055785:Gene Knockdown Techniques; D006801:Humans; D007328:Insulin / Q000096:biosynthesis* / Q000378:metabolism*; D000078790:Insulin Secretion; D007340:Insulinoma / Q000473:pathology*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000172:deficiency* / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000099157:Sphingosine Kinase
chemical_list: D004791:Enzyme Inhibitors; D007328:Insulin; D017853:Phosphotransferases (Alcohol Group Acceptor); D013110:Sphingosine; D000099157:Sphingosine Kinase; C061800:N,N-dimethylsphingosine