The role of Rpl5 haploinsufficiency in hematopoietic stem/progenitor cell function in Diamond Blackfan anemia

项目摘要/摘要 贫血是一种非常常见的疾病，全球约三分之一的人受到影响。 红细胞生成对内源性和外源性压力都非常敏感，这也是造成这种情况的原因之一。 巨大的全球疾病负担。导致严重贫血的核糖体基因缺陷与 罕见的遗传性骨髓衰竭综合征以及更常见的获得性骨髓增生异常综合征。 钻石黑扇贫血患者从核糖体蛋白单倍体不足到红细胞生成缺陷的途径 (DBA)是复杂的，可能涉及多种因素(例如，GATA1翻译减少、血红素毒性和/或 核仁应激)。DBA患者可以自发缓解，因此慢性输血是 不是必需的。使用目前的患者登记和动物模型很难理解这一现象。 了解导致贫血缓解或改善的正常途径对于 治疗DBA和其他原因贫血的先进疗法。申请人为儿科血液学家/肿瘤学家。 世卫组织积极治疗所有类型的遗传性和获得性贫血患者，她的长期目标是成为 一位在造血学方面有专长的内科科学家。为了实现这一目标，候选人提出了 以下培训计划：1)培养造血干/祖细胞分离和分析方面的专业知识； 2)进一步发展利用小鼠模型和人类造血干细胞培养进行研究的专门知识 针对疾病的机制；3)发展一个独立资助的基础研究实验室；4)发展 成为一名专注于指导和合作的成功的内科科学家。这位候选人已经召集了一位 具有造血和小鼠模型专业知识的导师团队(恩格尔博士和李博士)。位于的环境 密歇根大学非常有助于成功的初级内科医生-科学家的培训 特殊的资源、教育和协作机会。这项科学提案的中心是 假设DBA的缓解，即使在这些近亲交配的小鼠中，也是基于对造血的阈值效应 对外源性和内源性修饰物均有反应的干/祖细胞。这样做的理由是 假设是基于对我们独特的DBA小鼠模型的观察，在该模型中，所有新生Rpl5(核糖体 蛋白质基因突变的小鼠出生时就患有贫血，这会导致一些小鼠的早期死亡，而另一些小鼠则会 在他们的一生中存活并保持正常的血红蛋白特征。目标一号将确定是否有 是突变小鼠的干细胞/祖细胞和/或骨髓微环境的固有缺陷 研究不同发育时期的造血细胞移植。Aim 2将测试 细胞应激改变了壁龛和/或造血干/祖细胞的功能。目标3将考察 细胞周期失调是发育易损期造血功能障碍的原因 或者在细胞应激期间。在资深导师的指导下完成培训将使申请者 发展成为一名在造血方面拥有更多专业知识的独立内科科学家。

PROJECT SUMMARY/ABSTRACT Anemia is an extraordinarily common condition that affects approximately 1 in 3 people around the globe. Erythropoiesis is exquisitely sensitive to both endogenous and exogenous stress, which contributes to this massive global disease burden. Genetic defects in ribosomes that lead to severe anemia are associated with rare inherited bone marrow failure syndromes as well as more commonly acquired myelodysplastic syndrome. The pathway from ribosomal protein haploinsufficiency to defective erythropoiesis in Diamond Blackfan anemia (DBA) is complex and likely involves multiple factors (e.g. diminished GATA1 translation, heme toxicity and/or nucleolar stress). Patients with DBA can undergo spontaneous remission such that chronic transfusions are not required. This phenomenon is poorly understood using current patient registries and animal models. Understanding normal pathways that lead to the resolution or improvement of anemia is critical in order to advance therapies for DBA and other causes of anemia. The applicant is a pediatric hematologist/oncologist who actively treats patients with all types of genetic and acquired anemias and her long term goal is to become a physician-scientist with expertise in hematopoiesis. To achieve this goal, the candidate has proposed the following training plan: 1) To develop expertise in isolation and analysis of hematopoietic stem/progenitor cells; 2) To further develop expertise employing mouse models and human hematopoietic stem cell culture to study disease-specific mechanisms; 3) To develop an independently funded basic research laboratory; 4) To develop into a successful physician-scientist focused on mentorship and collaboration. The candidate has assembled a mentorship team with expertise in hematopoiesis and mouse models (Drs. Engel and Li). The environment at the University of Michigan is highly conducive to the training of successful junior physician-scientists with exceptional resources, educational and collaborative opportunities. The scientific proposal centers on the hypothesis that DBA remission, even in these inbred mice, is based on a threshold effect on hematopoietic stem/progenitor cells that responds to both exogenous and endogenous modifiers. The rationale for this hypothesis is based on observations in our unique DBA mouse model where all neonatal Rpl5 (ribosomal protein gene) mutant mice are born with anemia, which contributes to early mortality in some mice while others survive and maintain normal hemoglobin characteristics throughout their lifespan. Aim 1 will determine if there is an intrinsic defect in stem/progenitor cells and/or the bone marrow microenvironment in mutant mice by examining transplantation of hematopoietic cells from different developmental periods. Aim 2 will test whether cellular stress alters the niche and/or hematopoietic stem/progenitor cell function. Aim 3 will examine whether cell cycle dysregulation is responsible for defective hematopoiesis during developmentally vulnerable periods or during cellular stress. Completion of training under the guidance of senior mentors will enable the applicant to develop into an independent physician-scientist with greater expertise in hematopoiesis.