Distinct translational control in CD4+ T-cell subsets

Regulatory T cells expressing the transcription factor Foxp3 play indispensable roles for the induction and maintenance of immunological self-tolerance and immune homeostasis. Genome-wide mRNA expression-studies have defined canonical signatures of T-cell subsets. Changes in steady-state mRNA levels do, however, often not reflect those of corresponding proteins due to post-transcriptional mechanisms including mRNA translation. Here, we unveil a unique translational signature, contrasting CD4+Foxp3+ regulatory T (TFoxp3+) and CD4+Foxp3- non-regulatory T (TFoxp3-) cells, which imprints subset-specific protein expression. We further show that translation of eukaryotic translation initiation factor 4E (eIF4E) is induced during T-cell activation and, in turn, regulates translation of cell cycle related mRNAs and proliferation in both TFoxp3- and TFoxp3+ cells. Unexpectedly, eIF4E also affects Foxp3 expression and thereby lineage identity. Thus, mRNA-specific translational control directs both common and distinct cellular processes in CD4+ T-cell subset. CD4+/Foxp3+ and CD4+Foxp3- cells were studied ex vivo or activated in vitro for 36h. Both polysome-associated and cytoplasmic RNA was isolated to enables studies of translational control