Figure 2
Decreased total ceramides and sphingomyelins and increased phosphorylated sphingoid bases after 24 h stimulation of mesangial cells with IL-1β and PDGF-BB. Lipidomics experiments showed a decrease of the whole sphingolipid cellular pool (Cer, LacCer, dhCer, GluCer, SM, dhSG, SG, S1P, dhS1P, PhytoSG) after the treatments (a) and the increase of phosphorylated sphingoid bases (b) compared to total sphingoid bases (dhSG, SG, S1P, dhS1P, PhytoSG). Data were normalized against cell count and divided by the relative cell count normalization factor. Sphk1 (phosphorylation of sphingoid bases) protein levels are increased by both stimulations, while Cerk (phosphorylation of ceramides) is downregulated at protein (c) and gene level (d). SPTLC1 (de novo ceramide synthesis) is not regulated at protein level (c) and CERS2 (dhCer synthesis from dhSG) is downregulated at the gene level (e). *P < 0.05; **P < 0.01; ***P < 0.001. Data are reported as mean ± SEM. Uncropped blots after chemiluminescence development and total protein stain free blots are presented in Supplementary Fig. S4b. Quantification of the bands in the western blot is reported in Supplementary Fig. S5.
