Fig. 4.

All identified 1-deoxySL metabolites are produced downstream of 1-deoxySO and form a branched pathway. A: MEF cells were treated with d3-deoxySA, 14,15-cis-1-deoxySO, 14,15-trans-1-deoxySO, and 4,5-trans-1-deoxySO for 48 h (indicated along the x axis) and the resulting 1-deoxySL downstream metabolites were measured by LC/MS (d3-labeled for the d3-deoxySA treated condition and unlabeled for the other conditions; indicated by the different patterns). All metabolites were significantly increased compared with untreated controls upon treatment with any of the 1-deoxySO isomers. Statistical significance was calculated for individual metabolites arising from each treatment versus untreated controls using the Student’s t-test. B: MEF cells were treated with isolated d3-deoxySA, d3-deoxySA-OH, and d3-deoxySO-OH (a mix of both I and II; indicated along the x axis) for 48 h, and the resulting downstream d3-labeled 1-deoxySL metabolites were measured by LC/MS (indicated by the different patterns). The amounts of each downstream metabolite produced from the different treatments were compared in pairs and significance was calculated using the Student’s t-test. C: Proposed metabolic pathway order. All bars represent averages ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.