INTEGRATION OF DNA DAMAGE RESPONSES WITH IMMUNE DEVELOPMENT AND FUNCTION

描述（由申请人提供）：精确控制淋巴细胞的发育，以产生多种抗原受体库，同时防止有害事件，如易位，促进细胞转化和淋巴细胞恶性肿瘤。这两个对立但相互依赖的过程是通过多种细胞信号的合作来管理的，这些信号控制着细胞的增殖、存活和抗原受体的组装。我们描述了一种新的信号通路，在前b细胞是由抗原受体重组过程中产生的生理性DNA断裂启动。令人惊讶的是，我们的工作表明，DNA断裂依赖的信号矛盾地激活了生存途径，这对于确保抗原受体基因重排的足够时间很重要。然而，如果DNA断裂无法修复，同样的DNA损伤反应会触发细胞死亡，以防止易位并保护基因组完整性。这种生存和细胞凋亡的时间平衡是生理性DNA断裂所特有的，因为基因毒性损伤，如伽马辐射，在没有初始生存期的情况下诱导细胞立即死亡。该项目的目的是阐明协调生存和细胞死亡信号的机制，以响应淋巴细胞的DNA断裂。利用允许分离DNA断裂信号和表面受体信号的实验方法，我们建议：1)定义控制存活动力学的生理性DNA断裂的特性，2)识别响应DNA断裂调节延迟凋亡信号的信号，以及3)定义DNA断裂信号和免疫调节因子（即CD40）在调节淋巴细胞存活中的功能整合。最终，这项工作将阐明平衡存活和细胞死亡的新信号网络

DESCRIPTION (provided by applicant): Lymphocyte development is precisely controlled to enable generation of a diverse antigen receptor repertoire while, simultaneously, preventing deleterious events, such as translocations, which promote cellular transformation and lymphoid malignancies. These two dichotomous but interdependent processes are managed through the cooperation of diverse cellular signals, which control cell proliferation, survival, and antigen receptor assembly. We describe a novel signaling pathway in pre-B cells that is initiated by the physiologic DNA breaks generated during antigen receptor recombination. Surprisingly, our work demonstrates that DNA break-dependent signals paradoxically activate survival pathways that are important to ensure adequate time for antigen receptor gene rearrangement. However, if DNA breaks cannot be repaired, the same DNA damage responses trigger cell death to prevent translocations and protect genomic integrity. This temporal balance of survival and apoptosis is unique to physiologic DNA breaks as genotoxic insults, such as gamma irradiation, induce immediate cell death without an initial survival period. The goal of this project is to elucidate the mechanisms that coordinate survival and cell death signaling in response to DNA breaks in lymphocytes. Utilizing an experimental approach that permits isolation of DNA break signals and surface receptor signals, we propose to: 1) define the properties of physiologic DNA breaks that control survival kinetics, 2) identify the signals that regulate delayed apoptotic signaling in response to DNA breaks, and 3) define the functional integration of signals from DNA breaks and immune regulators (i.e., CD40) in the regulation of lymphocyte survival. Ultimately, this work will elucidate new signaling networks that balance survival and cell death in developing lymphocytes to ensure normal maturation and inhibit leukemogenesis. These investigations will establish the foundation for an independent scientific career focused on applying basic immunology research to the pathogenesis of clinical diseases, particularly immune deficiencies and lymphoid malignancies. The mentored period of this award will provide protect time to develop new techniques for studying DNA damage responses in lymphocytes and to acquire new skills necessary for managing a research laboratory. These tools will be essential for completion of the outlined experiments and for the germination of an independent research program. A collaborative and robust immunology research environment will help guide future research directions. This application presents a research program and a career development plan that will provide the framework and skills necessary for establishing independence and competing for extramural funding.