Ibuprofen inhibits tryptophan import, reduces intracellular tryptophan levels and does not extend RLS in the absence of tryptophan permeases.

A, Uptake of [¹⁴C]-tryptophan (y axis) is shown at the indicated time points (x axis) after the cells were exposed to, and allowed to internalize, [¹⁴C]-tryptophan, together with ibuprofen, rapamycin, or no treatment, as indicated. The average of 2 independent experiments is shown, while the error bars indicate the variability between the two experiments. B, Intracellular amino acid pools. The percentage difference in the amino acid levels between the ibuprofen-treated (0.2 mM) and untreated (0 mM) samples is shown on the x-axis. The average of six independent experiments (each analyzed in quadruplicate) and the associate standard deviation is shown. All the obtained values from these amino acid analyses are shown in S3 Table. C, Survival curves for MATα tat2Δ cells (BY4742 strain background) treated with ibuprofen at 0.2 mM (shown in purple), compared to experiment-matched untreated cells (shown in red). For comparison, wild type (WT) cells (BY4742 background) were also included in this experiment and they were either untreated (shown in black) or treated (shown in blue) with ibuprofen. Mean lifespans are shown in parentheses, along with the number of cells assayed. D, Survival curves for wild type and tat1Δ, tat2Δ cells (BY4741 strain background) treated with ibuprofen at 0.2 mM compared to experiment-matched untreated cells. Mean lifespans are shown in parentheses, along with the number of cells assayed.