Status of ceramide and dihydroceramide to confirm the acceptability of our in vitro model.

<p><b>A.</b> Structure of dihydroceramide and ceramide. <b>B.</b> Des 1 knock out MEFs do not express Des1 mRNA (upper panel) as well as Des1 protein (lower panel). <b>C.</b> Des1 deletion inhibits ceramide formation and causes accumulation of dihydroceramide (*<i>P</i><0.01, **<i>P</i><0.003). <b>D.</b> To confirm the efficiency of <i>Des1</i> ablation, downstream metabolites of ceramide and dihydroceramide were detected. Ceramide containing <i>Des1 +/+</i> cells contain sphingomyelin while the <i>Des1 −/−</i> contain mostly its dihydro-species, dihydrosphingomyelin (*<i>P</i><0.05, # not significant). <b>E.</b> A similar pattern was observed for levels of sphingosine and dihydrosphingosine (*<i>P</i><0.01, **<i>P</i><0.05). The data represent the average values of experiments which have been done at least in triplicates. For all panels, paired t-test has been used for statistical analysis.