Role of DNA Damage Responses in Immune Development and Function

DNA 损伤反应在免疫发育和功能中的作用

基本信息

批准号：
10197574
负责人：
Jeffrey J Bednarski
金额：
$ 31.5万
依托单位：
WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-01 至 2022-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10197574
关键词：
Antibody Repertoire B Cell Proliferation B cell differentiation B-Cell Development B-Cell Leukemia B-Lymphocytes Cell Cycle Cell Cycle Arrest Cell Maturation Cell Proliferation Cells Clonal Expansion Complex DNA DNA Damage DNA Double Strand Break Development Double Strand Break Repair Ensure Equilibrium Extinction (Psychology)Gene Rearrangement Generations Genes Genetic Recombination Genetic Transcription Genome Stability Goals Immune Immunoglobulin Light Chain Genes Light-Chain Immunoglobulins Lymphoblastic Leukemia Lymphocyte Malignant - descriptor Mediating Modeling Pathway interactions Phosphotransferases Physiological Population Process Protein Tyrosine Kinase RAG1 gene Receptor Gene Receptor Signaling Regulation Regulator Genes Repressor Proteins Role SYK gene Signal Transduction Site Surface System TP53 gene Testing Therapeutic Transcription Repressor Tumor Suppressor Proteins Work cell assembly cell type genome integrity genotoxicity immunoglobulin receptor innovation irradiation leukemia leukemic transformation novel novel therapeutics pre-B cell receptor preservation prevent programs receptor recruit repaired response transcription factor ubiquitin ligase

项目摘要

PROJECT SUMMARY Lymphocyte development is precisely controlled to enable clonal expansion and generation of a diverse immunoglobulin receptor repertoire, which proceeds through DNA double-stranded breaks (DSBs). These two dichotomous, but interdependent processes, are managed through the cooperation of diverse cellular signals to prevent cells with DSBs from entering cell cycle where they could be aberrantly repaired as translocations. During early B cell development, the pre-B cell receptor (pre-BCR), through activation of the SYK kinase, coordinates both the proliferative expansion of pre-B cells and the assembly of immunoglobulin receptor genes. Negative regulation of the pre-BCR is required to enforce cell cycle arrest and limit the number of DNA breaks generated during immunoglobulin receptor gene assembly. Indeed, unopposed pre-BCR signaling, particularly increased SYK activity, drives proliferation and leukemic transformation. We have identified a novel cell-type specific checkpoint pathway activated by signals from DSBs that inhibits pre-BCR signaling. The physiologic DSBs generated during immunoglobulin receptor gene rearrangement trigger DNA damage responses that suppress SYK kinase activity downstream of the pre-BCR. Surprisingly, this signaling network is not triggered by genotoxic DNA injury and, thus, is specific to the DSBs generated during normal B cell differentiation. In early B cells, distinct cellular responses to physiologic and genotoxic DSBs are essential for ensuring normal B cell differentiation and inhibiting leukemic transformation. Our goal is to determine how signals from DSBs integrate with developmental programs to coordinate B cell maturation. We propose that early B cells toggle between signals from the pre-BCR and DSBs to order immunoglobulin receptor gene assembly and maintain genomic stability by preventing proliferation of cells with DSBs. Utilizing an innovative experimental approach that permits isolation of DSB signals and surface receptor signals, we propose to: 1) define the transcriptional repressor complex that regulates DSB-mediated checkpoints, 2) identify the DSB-dependent post-translational pathways that suppress pre-BCR signaling, and 3) determine the DSB-specific pathways that dictate the unique cellular responses to physiologic versus genotoxic insults. Completion of these studies will delineate a set of mechanisms critical for dampening pre-BCR signals, will establish novel paradigms for cell- type specific checkpoints to DSBs, and will define the underlying principles for discrete cellular responses to physiologic versus genotoxic DSBs.

项目概要精确控制淋巴细胞的发育，以实现克隆扩增和生成多样化的细胞免疫球蛋白受体库，通过 DNA 双链断裂 (DSB) 进行。这两个二分但相互依赖的过程是通过不同细胞信号的合作来管理的防止带有 DSB 的细胞进入细胞周期，在细胞周期中它们可能会因易位而被异常修复。期间早期 B 细胞发育中，前 B 细胞受体 (pre-BCR) 通过激活 SYK 激酶，协调前 B 细胞的增殖扩张和免疫球蛋白受体基因的组装。消极的需要调节前 BCR 来强制细胞周期停滞并限制产生的 DNA 断裂数量在免疫球蛋白受体基因组装过程中。事实上，未受对抗的前 BCR 信号传导，特别是增加 SYK 活性可促进增殖和白血病转化。我们已经鉴定出一种新的细胞类型特异性检查点通路由 DSB 信号激活，抑制前 BCR 信号传导。生理 DSB 免疫球蛋白受体基因重排过程中产生的DNA损伤反应会抑制前 BCR 下游的 SYK 激酶活性。令人惊讶的是，这个信号网络不是由基因毒性触发的 DNA 损伤因此对正常 B 细胞分化过程中产生的 DSB 具有特异性。在早期 B 细胞中，对生理和基因毒性 DSB 的不同细胞反应对于确保 B 细胞正常至关重要分化并抑制白血病转化。我们的目标是确定来自 DSB 的信号如何与发育程序整合以协调 B 细胞成熟。我们建议早期 B 细胞在来自前 BCR 和 DSB 的信号之间切换以命令免疫球蛋白受体基因组装和通过 DSB 防止细胞增殖来维持基因组稳定性。利用创新的实验允许分离 DSB 信号和表面受体信号的方法，我们建议：1）定义调节 DSB 介导的检查点的转录阻遏复合物，2) 识别 DSB 依赖性抑制 BCR 前信号传导的翻译后途径，以及 3) 确定 DSB 特异性途径决定了细胞对生理和基因毒性损伤的独特反应。完成这些研究将描述了一组对于抑制 BCR 前信号至关重要的机制，将为细胞建立新的范例为 DSB 键入特定的检查点，并将定义离散细胞响应的基本原则生理性 DSB 与基因毒性 DSB。