Department of Neurobiology, Interdisciplinary Center for Neurosciences, Heidelberg University, 69120, Heidelberg, Germany.
Department of Immunology, Heidelberg University, 69120, Heidelberg, Germany.
Mol Immunol. 2019 Oct;114:81-87. doi: 10.1016/j.molimm.2019.07.006. Epub 2019 Jul 23.
Calcium is a key regulator of the T cell immune response. Depending on the spatial properties (nucleus versus cytoplasm) of the calcium signals generated after CD3xCD28 stimulation, primary human T cells either mount a productive immune response or develop tolerance. Nuclear calcium acts as a genomic decision maker: during T cell activation, it drives expression of genes associated with a productive immune response while in its absence, stimulated T cells acquire an anergy-like gene profile. Selective inhibition of nuclear calcium signaling in stimulated T cells blocks the productive immune response and directs the cells towards an anergy-like state. Here we show that the two transcriptional programs that include, respectively, the 'activation gene', interleukin 2 (IL2) and 'anergy-related genes', EGR2, EGR3, and CREM have different requirements for transmembrane calcium flux. By either lowering extracellular calcium concentrations with EGTA or using low concentrations of the ORAI blockers, BTP2 or RO2959, we reduced transmembrane calcium flux in human primary T cells stimulated with CD3xCD28. These 'conditions of limited calcium influx' (CLCI) blocked CD3xCD28-induced IL2 expression but only moderately affected induction of the anergy-related genes EGR2, EGR3, and CREM. We observed no difference in NFAT2 nuclear translocation after CD3xCD28 stimulation between normal conditions and CLCI. These results indicate that CLCI favors expression of anergy-related genes in activated human T cells. CLCI may be used to develop novel means for pro-tolerance immunosuppressive treatments.
钙是 T 细胞免疫反应的关键调节剂。根据 CD3xCD28 刺激后产生的钙信号的空间特性（核与细胞质），原代人 T 细胞要么启动有效的免疫反应，要么发展为耐受。核钙作为基因组决策因子：在 T 细胞激活期间，它驱动与有效免疫反应相关的基因表达，而在其不存在的情况下，受刺激的 T 细胞获得类似无反应的基因谱。选择性抑制受刺激的 T 细胞中的核钙信号会阻断有效的免疫反应，并将细胞导向类似无反应的状态。在这里，我们表明，包括分别包含“激活基因”白细胞介素 2 (IL2)和“无反应相关基因”EGR2、EGR3 和 CREM 的两个转录程序对跨膜钙通量有不同的要求。通过用 EGTA 降低细胞外钙浓度或使用低浓度的 ORAI 阻滞剂 BTP2 或 RO2959，我们减少了用 CD3xCD28 刺激的人原代 T 细胞中的跨膜钙通量。这些“有限钙内流条件”（CLCI）阻断了 CD3xCD28 诱导的 IL2 表达，但仅适度影响了无反应相关基因 EGR2、EGR3 和 CREM 的诱导。我们在正常条件和 CLCI 之间观察到 CD3xCD28 刺激后 NFAT2 核易位没有差异。这些结果表明，CLCI 有利于激活的人 T 细胞中无反应相关基因的表达。CLCI 可用于开发新的耐受诱导免疫抑制治疗方法。
