Themis is a T cell lineage-specific molecule that is involved in TCR signal transduction. The effects of germline Themis deletion on peripheral CD4⁺ T cell function have not been described before. In this study, we found that Themis-deficient CD4⁺ T cells had poor proliferative responses, reduced cytokine production in vitro and weaker inflammatory potential, as measured by their ability to cause colitis in vivo. Resting T cells are quiescent, whereas activated T cells have high metabolic demands. Fulfillment of these metabolic demands depends upon nutrient availability and upregulation of nutrient intake channels after efficient TCR signal transduction, which leads to metabolic reprogramming in T cells. We tested whether defects in effector functions were caused by impaired metabolic shifts in Themis-deficient CD4⁺ T cells due to inefficient TCR signal transduction, in turn caused by the lack of Themis. We found that upon TCR stimulation, Themis-deficient CD4⁺ T cells were unable to upregulate the expression of insulin receptor (IR), glucose transporter (GLUT1), the neutral amino acid transporter CD98 and the mTOR pathway, as measured by c-Myc and pS6 expression. Mitochondrial analysis of activated Themis-deficient CD4⁺ T cells showed more oxidative phosphorylation (OXPHOS) than aerobic glycolysis, indicating defective metabolic reprogramming. Furthermore, we found reduced NFAT translocation in Themis-deficient CD4⁺ T cells upon TCR stimulation. Using previously reported ChIP-seq and RNA-seq data, we found that NFAT nuclear translocation controls IR gene expression. Together, our results describe an internal circuit between TCR signal transduction, NFAT nuclear translocation, and metabolic signaling in CD4⁺ T cells.

Themis 是一种 T 细胞谱系特异性分子，参与 TCR 信号转导。种系 Themis 缺失对外周 CD4 ⁺ T 细胞功能的影响以前没有被描述过。在这项研究中，我们发现 Themis-deficient CD4 ⁺T 细胞的增殖反应较差，体外细胞因子产生减少，炎症潜能较弱，这可以通过它们在体内引起结肠炎的能力来衡量。静止的 T 细胞处于静止状态，而活化的 T 细胞具有很高的代谢需求。这些代谢需求的满足取决于有效的 TCR 信号转导后营养物质的可用性和营养摄入通道的上调，这导致 T 细胞中的代谢重编程。^{我们测试了效应器功能的缺陷是否是由于 TCR 信号转导效率低下导致 Themis 缺陷型 CD4 +} T 细胞的代谢转变受损，进而由 Themis 缺乏引起的。我们发现在 TCR 刺激下，Themis 缺陷型 CD4 ⁺通过 c-Myc 和 pS6 表达测量，T 细胞无法上调胰岛素受体 (IR)、葡萄糖转运蛋白 (GLUT1)、中性氨基酸转运蛋白 CD98 和 mTOR 途径的表达。^{活化的 Themis 缺陷 CD4 +} T 细胞的线粒体分析显示氧化磷酸化 (OXPHOS) 比有氧糖酵解更多，表明代谢重编程缺陷。此外，我们发现在 TCR 刺激后 Themis 缺陷 CD4 ⁺ T 细胞中 NFAT 易位减少。使用先前报道的 ChIP-seq 和 RNA-seq 数据，我们发现 NFAT 核易位控制IR基因表达。总之，我们的结果描述了 TCR 信号转导、NFAT 核易位和 CD4 中的代谢信号之间的内部电路⁺ T 细胞。