Sphingolipid changes do not underlie fatty acid-evoked GLUT4 insulin resistance nor inflammation signals in muscle cells

Supplemental Data

• Supplemental Figure S1 (.pptx, 60 KB) - Supplemental Figure S1. Palmitate and palmitoleate do not change the expression of enzymes of the sphingolipid pathway. A. Diagram showing the different steps of the sphingolipid pathway and which enzymes are inhibited by myriocin, fenretinide and fumonisin B1 (n=4). B-C. L6 myotubes were exposed to 0.5 mM PA, (O or the BSA vehicle for 18h. Cell were extracted and qPCR performed as described in methods using specific primers for several enzymes of the sphingolipid pathway. N.D.=not detectable.
• Supplemental Figure S2 (.pptx, 94 KB) - Supplemental Figure S2. Effect of sphingolipid pathway inhibition on other lipid species. Lipidomics analysis was performed in L6 muscle cells exposed to inhibitors of the sphingolipid pathway before treatment with palmitate (PA) of the BSA vehicle (BSA). A. Myriocin (MYR), B. fenretinide (FEN) and C. fumonisin B1 (FB1).
• Supplemental Figure S3 (.pptx, 74 KB) - Supplemental Figure S3. Inhibiting hexosylceramide formation, sphingosine kinase activity or the TLR4-NF??B pathway activation does not prevent insulin resistance of GLUT4 translocation by palmitate. Insulin-induced surface GLUT4 was measured in L6 muscle cells exposed to various inhibitors. A. Inhibition of glucosylceramide synthase (PDMP, 20-40 ??M). B. Inhibition of sphingosine kinase (SKI-II, 5-20 ??M). C. Inhibition of the NFkB pathway: TLR4 (TAK242, 100 ??M), cardamonin (CARD, 50 ??M), caffeic acid phenethyl ester (CAPE, 10 ??M) and parthenolide (PTN, 10 ??M). *Significant effect of PA over BSA control (2-way ANOVA, p<0.05). ??Significant effect of insulin over unstimulated control (p<0.05).
• Supplemental Table S1 (.xlsx, 73 KB) - Lipidomics data and statistical analysis