SYK and ZAP70 kinases in lymphocyte selection

SYK 和 ZAP70 激酶在淋巴细胞选择中的作用

基本信息

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
项目类别：
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

项目摘要

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.

抽象的虽然B细胞面临着强烈的选择压力，以消除自动反应性和恶性克隆，但我们将SYK确定为中央激酶，以设定负选择的阈值。 Syk及其高度同源相对ZAP70启动B细胞受体（BCR）和T细胞受体（TCR）信号传导 T淋巴细胞分别。即使这两个激酶几乎相同，并且具有类似的作用在整个进化过程中，它们在B-和T细胞中的表达被严格隔离。而两种激酶分离的原因尚不清楚，Syk和Zap70的异常共表达为先前在B细胞慢性淋巴细胞性白血病（CLL）和周围T细胞淋巴瘤中报道（PTCL）。我们的小组最近表明，异常的ZAP70表达是前pre- 生发中心（GC）B细胞恶性肿瘤（B-All，Cll，Mcl； Sadras等，Mol Cell 2021）。通用 B-all和B-CLL的小鼠模型，ZAP70加速疾病发作的诱导共表达，而遗传缺失受损的恶性转化。同样，ZAP70在早期的B细胞发育颠覆了自动反应性B细胞的负面选择，以促进普遍性自身抗体生产。从机械上讲，ZAP70与SYK竞争，并对SYK依赖性执行主导性影响 Ca2+信号。通过占据但不占磷酸化的blnk，BTK和PLC2底物的上游钙信号传导，ZAP70大大降低了自主Ca2+振荡的频率。快速地 SYK（4.5 MHz）唯一存在的振荡被NFATC1解码，并导致反感细胞死亡。相比之下，在ZAP70（0.25 MHz）存在下缓慢的Ca2+振荡促进选择性 NF-B和B细胞存活和增殖的激活。我们在这里检验了中心假设，即B细胞在下游自动反应性BCR或通过SYK依赖性高频Ca2+ - 转化的癌基因 - 振荡。在高频下，Ca2+振荡激活NFATC1以启动B细胞厌食和克隆删除。相反，ZAP70减慢Ca2+振荡激活NF-B，而不是NFATC1和启用自动反应性和前B细胞克隆，并最终引起自身免疫性疾病或GC前B细胞Malignancys。我们提出的三个目标是（1）阐明ZAP70减慢SYK-的机制依赖性高频Ca2+振荡，至（2）确定ZAP70的共表达方式自身免疫性疾病中自动反应性B细胞的阴性选择和（3）揭示了ZAP70如何实现了恶性前B细胞的致癌信号传导和明显的恶性转化。