Fig. 4. SPTLC1 deficiency reduces c-Myc, HIF-1α, and mTORC1 signaling.

(A) Naïve CD4⁺T cells from WT and KO were differentiated under T_H17 conditions for 12 hours and scored for frequency of phospho-S6⁺ cells by flow cytometry. The left panel is a representative flow figure, and the right panel shows the cumulative percent pS6-positive cells. n = 5 biologically independent samples. (B) Immunoblot of p-4E-BP1 in WT and KO naïve CD4⁺ T cells differentiated for 12 hours under T_H17 polarizing conditions. The left panel shows representative Western blot, and the right panel is the quantitative data for the same. n = 5 biologically independent samples from two independent experiments. (C) GSEA for mTORC1 signaling genes between WT and KO T_H17 cells. (D) WT and KO naïve T cells were differentiated into T_H17 cells for 3 days and Hif1a mRNA quantified by qPCR. n = 5 biologically independent samples. (E) Immunoblot of HIF-1α in WT and KO naïve CD4⁺ T cells differentiated for 3 days under T_H17 polarizing conditions. The left panel shows representative Western blot, and the right panel is the quantitative data for the same. n = 3 biologically independent samples. (F) Myc mRNA quantified by qPCR in cells differentiated as in (D). n = 5 biologically independent samples. (G) Immunoblot of c-Myc in WT and KO naïve CD4⁺ T cells differentiated for 12 hours under T_H17 polarizing conditions. The left panel shows representative Western blot, and the right panel is the quantitative data for the same. n = 5 biologically independent samples from two independent experiments. (H and I) GSEA for hallmark gene sets (H) c-Myc target genes and (I) HIF-1α target genes between WT and KO T_H17 cells. Each dot represents an individual mouse. All data presented as means ± SEM: **P < 0.01; ***P < 0.001; ****P < 0.0001; ns, not significant.