Journal: Cell Reports Medicine
Article Title: L-Phenylalanine is a metabolic checkpoint of human Th2 cells
doi: 10.1016/j.xcrm.2025.102466
Figure Lengend Snippet: L-phenylalanine inhibits Th2 cell proliferation and mTOR and STAT6 phosphorylation as well as expression of type 2 transcription factors, cytokines, activation, and pathogenicity markers (A) Phe uptake into Th2 cells. In vitro -differentiated Th2 cells from 3 different donors were incubated in indicated conditions for 6 h, and intracellular Phe was colorimetrically quantified in lysates. (B and C) Proliferation (B) and viability (C) of in vitro differentiated Th2 cells subjected to high doses of additional Phe. Bar graphs show fold changes compared to vehicle-treated, activated cells. n = 3 different donors. (D and E) IL4I1 mRNA expression (D) and representative WB image of IL4I1 protein expression (E) in in vitro -differentiated Th2 cells following incubation in increasing doses of Phe with/without concurrent activation. mRNA ( n = 6–8 different donors) and protein expression ( n = 3 different donors). (F) Volcano plot of differentially expressed genes (DEGs, raw p value < 0.05) between activated Th2 cells treated with Phe (1mM) vs. vehicle for 24 h, obtained by RNA-seq analysis ( n = 5 different donors). Genes related to STAT6/mTOR/AMPK signaling, critical for T cell activity, are highlighted in boxes. (G and H) Significantly enriched downregulated (G) and upregulated (H) GO processes in Th2 cells following treatment as in (F). STRING analysis was conducted with significantly changed DEGs (raw p value < 0.05), and relevant enriched pathways are presented. (I–M) Representative WB image (I and K) and quantification (J, L, and M) of phosphorylation of STAT6 and mTOR, respectively, in in vitro -differentiated Th2 cells ( n = 3 different donors) treated with CD2, CD3, and CD28 activation antibodies with/without additional supplementation of 1 mM of Phe for indicated time points. (N) Heatmap of mRNA expression of critical transcription factors, cytokines, and activation markers in activated in vitro -differentiated Th2 cells treated with increasing doses of Phe. mRNA expression was determined using RT-qPCR. n = 6–8 different donors. Data are analyzed using one-way ANOVA with Dunnett’s correction. Z scores were determined and plotted as heatmap with different genes mentioned as rows. Data are row normalized. (O) Frequency of activated IL4 + Th2 cells with/without additional supplementation of 1 mM of Phe ( n = 4 different donors). (P) Frequency of activated CD3 + CD4 + CCR4 + GATA3 + CD161 + Th2 cells following incubation with/without supplementation of 1 mM Phe for 24 h ( n = 3 different donors). (A–D, J, L, M, N, O, and P) Each dot represents one donor. (A–C, J, L, M, O, and P) Paired t test was used for analysis. Bars represent mean ± SEM. ∗ p < 0.05, ∗∗ p < 0.01, and ∗∗∗ p < 0.001. See also and , , and .
Article Snippet: Next, total CD3 + CD4 + T cells or memory CD3 + CD4 + T cells were isolated using the human CD4 + T cell Isolation Kit or Memory CD4 + T cell Isolation Kit (Miltenyi Biotec, Bergisch Gladbach, Germany), for respective cell types, according to manufacturer instructions on the autoMACS Pro Separator (Miltenyi Biotec, Bergisch Gladbach, Germany).
Techniques: Phospho-proteomics, Expressing, Activation Assay, In Vitro, Incubation, RNA Sequencing, Activity Assay, Quantitative RT-PCR