SYK and ZAP70 kinases in lymphocyte selection

SYK 和 ZAP70 激酶在淋巴细胞选择中的作用

• 批准号: 10557882
• 负责人: Eric Meffre
• 金额: $ 61.73万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-01 至 2027-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10557882
• 关键词: Ablation; Acceleration; Acute; Alleles; Antibodies; Autoantibodies; Autoimmune Diseases; B lymphoid malignancy; B-Cell Acute Lymphoblastic Leukemia; B-Cell Antigen Receptor; B-Cell Development; B-Cell Lymphomas; B-Cell Neoplasm; B-Lymphocytes; BLNK gene; Biological Markers; Calcium Signaling; Cell Death; Cell Proliferation; Cell Survival; Cells; Chronic Lymphocytic Leukemia; Clonal Deletion; Clone Cells; Development; Dominant-Negative Mutation; Engineering; Etiology; Evolution; Flare; Frequencies; Genetic; Genetic study; Human; Impairment; Knock-in; Lymphocyte; Malignant - descriptor; Mediating; Mus; Oncogenes; Oncogenic; Onset of illness; Output; PIK3CG gene; Pathologic; Patients; Peripheral; Phosphoric Monoester Hydrolases; Phosphotransferases; Preclinical Testing; Production; Protein Analysis; Receptor Signaling; Reporting; Reverse Transcriptase Polymerase Chain Reaction; Rheumatoid Arthritis; SYK gene; Signal Transduction; Structure of germinal center of lymph node; Systemic Lupus Erythematosus; T-Cell Development; T-Cell Lymphoma; T-Cell Receptor; T-Lymphocyte; Testing; ZAP-70 Gene; analog; anergy; autoreactive B cell; autoreactivity; cell transformation; humanized mouse; inducible gene expression; loss of function; mouse model; mutant; novel; optogenetics; patient derived xenograft model; pharmacologic; phosphoproteomics; premalignant; pressure; prevent; promoter; remote control; segregation; single cell proteins; small molecule inhibitor; stoichiometry

ABSTRACT While B-cells are under intense selective pressure to eliminate autoreactive and pre-malignant clones, we identified SYK as central kinase to set the thresholds for negative selection. SYK and its highly homologous relative ZAP70 initiate B-cell receptor (BCR) and T-cell receptor (TCR) signaling in B- and T-lymphocytes, respectively. Even though the two kinases are almost identical and serve analogous functions, their expression in B- and T-cells is strictly segregated throughout evolution. Whereas the reason for separation of the two kinases is not known, aberrant coexpression of Syk and Zap70 was previously reported in B-cell chronic lymphocytic leukemia (CLL) and in peripheral T-cell lymphoma (PTCL). Our group recently demonstrated that aberrant ZAP70 expression is a common feature in pre- germinal center (GC) B-cell malignancies (B-ALL, CLL, MCL; Sadras et al., Mol Cell 2021). In genetic mouse models for B-ALL and B-CLL, inducible coexpression of Zap70 accelerated disease onset, while genetic deletion impaired malignant transformation. Likewise, inducible expression of Zap70 during early B-cell development subverted negative selection of autoreactive B-cells to promote pervasive autoantibody production. Mechanistically, ZAP70 competes with SYK and exerts a dominant-negative effect on SYK-dependent Ca2+-signaling. By occupying but not phosphorylating BLNK, BTK and PLC2 substrates upstream of calcium signaling, ZAP70 dramatically reduces the frequency of autonomous Ca2+-oscillations. Fast oscillations in the sole presence of SYK (4.5 mHz) are decoded by NFATC1 and result in anergy and cell death. In contrast, slow Ca2+-oscillations in the presence of ZAP70 (0.25 mHz) promote selective activation of NF-B and B-cell survival and proliferation. We test here the central hypothesis that B-cells sense pathological signaling downstream of an autoreactive BCR or a transforming oncogene through SYK-dependent high-frequency Ca2+- oscillations. At high frequencies, Ca2+-oscillations activate NFATC1 to initiate B-cell anergy and clonal deletion. Conversely, ZAP70 slows down Ca2+-oscillations to activate NF-B instead of NFATC1 and enables autoreactive and premalignant B-cell clones to persist and eventually give rise to autoimmune disease or pre-GC B-cell malignancies. We are proposing three Aims to (1) elucidate the mechanisms by which ZAP70 slows down SYK- dependent high-frequency Ca2+-oscillations, to (2) determine how coexpression of ZAP70 subverts negative selection of autoreactive B-cells in autoimmune disease and (3) to uncover how ZAP70 enables oncogenic signaling and overt malignant transformation of pre-malignant B-cells.

摘要 虽然B细胞处于强烈的选择压力下，以消除自身反应和癌前克隆， 我们将SYK鉴定为中枢激酶以设定阴性选择的阈值。SYK及其高度 同源相对ZAP 70在B-和 T淋巴细胞。尽管这两种激酶几乎相同， 由于它们的功能，它们在B细胞和T细胞中的表达在整个进化过程中是严格分离的。而 分离这两种激酶的原因尚不清楚，Syk和Zap 70的异常共表达是由于 先前在B细胞慢性淋巴细胞白血病（CLL）和外周T细胞淋巴瘤中报告 （PTCL）。我们的研究小组最近证明，ZAP 70的异常表达是前乳腺癌的一个共同特征。 老年中心（GC）B细胞恶性肿瘤（B-ALL，CLL，MCL; Sadras等，Mol Cell 2021）。遗传 在B-ALL和B-CLL小鼠模型中，Zap 70的可诱导共表达加速了疾病的发作， 基因缺失损害恶性转化。同样地，Zap 70的诱导型表达在 早期B细胞发育破坏了自身反应性B细胞的阴性选择， 自身抗体产生。 从机制上讲，ZAP 70与SYK竞争，并对SYK依赖性细胞发挥显性-负性作用。 Ca 2+信号转导。通过占据但不磷酸化BLNK、BTK和PLC的上游底物， 在钙信号传导中，ZAP 70显著降低自主Ca 2+振荡的频率。快速 在SYK（4.5 mHz）单独存在的情况下的振荡被NFATC 1解码，并导致无反应性， 细胞死亡相比之下，在ZAP 70（0.25 mHz）存在下的缓慢Ca 2+振荡促进选择性的细胞分裂。 NF-κ B B的活化和B细胞存活和增殖。 我们在这里测试的核心假设，即B细胞的感觉病理信号下游的一个 自身反应性BCR或通过SYK依赖性高频Ca 2 +- 振荡在高频率下，Ca 2+振荡激活NFATC 1以启动B细胞无反应性和克隆形成。 删除。相反，ZAP 70减慢Ca 2+振荡以激活NF-κ B B而不是NFATC 1， 使自身反应性和癌前B细胞克隆持续存在，并最终引起自身免疫性 疾病或GC前B细胞恶性肿瘤。 我们提出了三个目标：（1）阐明ZAP 70减缓SYK的机制， 依赖于高频Ca 2+振荡，以（2）确定ZAP 70的共表达如何颠覆 自身免疫性疾病中自身反应性B细胞的阴性选择和（3）揭示ZAP 70 使致癌信号和明显的恶性转化前B细胞。