Wortmannin and LY294002 inhibit myo-inositol accumulation by cultured bovine aorta endothelial cells and murine 3T3-L1 adipocytes.
We have previously reported that myo-inositol uptake and metabolism is reduced in human fibroblasts derived from patients with ataxia telangiectasia (AT). Treating normal fibroblasts with 10-100 microM wortmannin duplicates some of the phenotypic properties of AT fibroblasts including the decrease in myo-inositol accumulation. In the present study we examined whether treatment of other types of mammalian cells with wortmannin or LY294002 altered myo-inositol uptake. Cultured bovine aorta endothelial cells or 3T3-L1 adipocytes were incubated with either wortmannin or LY294002, and afterwards, myo-inositol uptake and SMIT mRNA levels were determined. Incubating cultured bovine aorta endothelial cells and 3T3-L1 adipocytes with either wortmannin or LY294002 caused a time- and concentration-dependent decrease in myo-inositol accumulation that was independent of changes in SMIT mRNA levels. The effect of wortmannin and LY294002 on myo-inositol accumulation was not due to an increase in myo-inositol secretion. The effect of LY294002 on myo-inositol accumulation was reversible. Furthermore, the LY294002-induced decrease in myo-inositol accumulation was specific since the uptake of serine or choline by cultured bovine aorta endothelial cells and 3T3-L1 adipocytes treated with LY294002 was not significantly decreased. Co-incubation of cultured bovine aorta endothelial cells and 3T3-L1 adipocytes with either wortmannin or LY294002 and hyperosmotic medium caused a significant decrease in the induction of myo-inositol accumulation by hyperosmolarity without significantly affecting the hyperosmotic-induced increase in SMIT mRNA levels. These data suggest that myo-inositol accumulation is regulated post-translationally by wortmannin and LY294002.
Yorek
M A
MA
Department of Internal Medicine, Diabetes-Endocrinology Research Centerand Veterans Affairs Medical Center (3 E 17), University of Iowa, Iowa City, IA 52246, USA. myorek@icva.gov
Dunlap
J A
JA
Lowe
W L
WL
D016475:3T3 Cells; D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism; D000730:Androstadienes / Q000494:pharmacology*; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics; D002417:Cattle; D002478:Cells, Cultured; D002794:Choline / Q000378:metabolism; D002867:Chromones / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics; D007294:Inositol / Q000378:metabolism*; D008565:Membrane Proteins; D051379:Mice; D009025:Morpholines / Q000494:pharmacology*; D009994:Osmolar Concentration; D019869:Phosphatidylinositol 3-Kinases / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D012694:Serine / Q000378:metabolism; D027981:Symporters; D013997:Time Factors; D000077191:Wortmannin
D000730:Androstadienes; D002352:Carrier Proteins; D002867:Chromones; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; D009025:Morpholines; D012333:RNA, Messenger; D027981:Symporters; C073884:SLC5A3 protein, human; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D012694:Serine; D007294:Inositol; D019869:Phosphatidylinositol 3-Kinases; D002794:Choline; D000077191:Wortmannin