Abstract：
Naturally occurring gain-of-function (GOF) mutants have been identified in patients for a variety of cytokine receptors. Although this constitutive activation of cytokine receptors is strongly associated with malignant disorders, ligand-independent receptor activation is also a useful tool in synthetic biology e.g. to improve adoptive cellular therapies with genetically modified T-cells. Balanced Interleukin (IL-)7 signaling via a heterodimer of IL-7 receptor (IL-7Rα) and the common γ-chain (γc) controls T- and B-cell development and expansion, whereas uncontrolled IL-7 signaling can drive acute lymphoid leukemia (ALL) development. The ALL-driver mutation PPCL in the transmembrane domain of IL-7Rα is a mutational insertion of the four amino acids proline-proline-cysteine-leucine and leads to ligand-independent receptor dimerization and constitutive activation. We showed here in the cytokine-dependent pre-B-cell line Ba/F3 that the PPCL-insertion in a synthetic version of the IL-7Rα induced γc-independent STAT5 and ERK phosphorylation and also proliferation of the cells and that booster-stimulation by arteficial ligands additionally generated non-canonical STAT3 phosphorylation via the synthetic IL-7Rα-PPCL-receptors. Transfer of the IL-7Rα transmembrane domain with the PPCL insertion into natural and synthetic cytokine receptor chains of the IL-6, IL-12 and Interferon families also resulted in constitutive receptor signaling. In conclusion, our data suggested that the insertion of the mutated PPCL IL-7Rα transmembrane domain is an universal approach to generate ligand-independent, constitutively active cytokine receptors.
摘要：
已经在患者中鉴定了各种细胞因子受体的天然存在的功能获得(GOF)突变体。尽管细胞因子受体的这种组成型激活与恶性疾病密切相关，不依赖配体的受体激活在合成生物学中也是有用的工具,例如用于改善使用遗传修饰的T细胞的过继性细胞疗法。通过IL-7受体（IL-7Rα）和共同的γ链（γc）的异源二聚体平衡的白介素（IL-）7信号控制T细胞和B细胞的发育和扩增，而不受控制的IL-7信号可以驱动急性淋巴细胞白血病（ALL）的发展。IL-7Rα跨膜结构域中的ALL驱动突变PPCL是四个氨基酸脯氨酸-脯氨酸-半胱氨酸-亮氨酸的突变插入，并导致不依赖配体的受体二聚化和组成型激活。我们在细胞因子依赖性前B细胞系Ba/F3中显示，在IL-7Rα的合成版本中插入PPCL诱导了不依赖γc的STAT5和ERK磷酸化以及细胞的增殖，并且通过人工配体的增强刺激还通过合成的IL-7Rα-PPCL受体产生了非常规STAT3磷酸化。将具有PPCL插入的IL-7Rα跨膜结构域转移到IL-6、IL-12和干扰素家族的天然和合成细胞因子受体链中也导致组成型受体信号传导。总之,我们的数据表明，插入突变的PPCLIL-7Rα跨膜结构域是产生不依赖配体的通用方法，组成型活性细胞因子受体。
