Controlling Hematopoietic Lineage Commitment from ESC to Platelets

描述(由申请人提供)： 骨髓移植告诉我们，造血是由多能造血干细胞支持的，这些干细胞可以在一生中维持或重建各种血细胞谱系。尽管我们对谱系承诺的理解取得了进展，但这并没有转化为治疗谱系特异性细胞减少症的改进方法。我们应用的目的是加深我们对谱系承诺的理解，并利用这一知识开发分子干预措施，在体外和体内都能推动造血向理想的谱系发展。由于移植后血小板减少的临床重要性，该应用程序特别专注于巨核细胞生成，并与我们在费城儿童医院的UOL合作伙伴最大限度地发挥协同作用。为了实现这一目标，我们提出了一个具有4个目标的多方面计划，每个目标涉及来自FHCRC/UW联盟的两名或更多调查人员。在目标1中，费罗博士、帕丁顿博士和托罗克-斯托布博士将在从小鼠、狗和人到血小板的干细胞途径中生成功能定义的祖细胞的分子图谱。这三个实验模型具有互补的优势，允许采用全面的方法，包括可以预测临床结果的强大的临床前体内模型。在目标2中，这些研究人员将对已定义的祖细胞进行基因修饰，以表达谱系阶段特异性的报告，以用于高含量、高投入的siRNA筛选试验，以确定将控制祖细胞命运的微环境的变化。第三个目标将测试不同的祖细胞亚群对有条件激活的信号分子的反应的增殖和分化潜力。为此，BRAU和Emery博士将使用信号分子衍生物，这些分子可以被称为化学二聚化诱导剂(CID)的小分子药物激活。在目标4中，Kiem博士和Blau博士将利用犬的血小板减少模型来测试目标2中确定的基因产品，以及目标3中扩大的细胞产品，以改善体内的血小板计数。这些狗模型的活体研究将在高度相关的临床前模型中建立这些疗法的安全性和有效性。

DESCRIPTION (provided by applicant): Marrow transplantation have taught us that hematopoiesis is supported by multipotent hematopoietic stem cells that can maintain or reconstitute the various blood cell lineages throughout life. Despite advances in our understanding of lineage commitment, this has not translated into improved approaches for treating lineage specific cytopenias. The goal of our application is to further our understanding of lineage commitment and use this knowledge to develop molecular interventions that will drive hematopoiesis toward desired lineages both in vitro and in vivo. The application is specifically focused on megakaryopoiesis, because of the clinical importance of post-transplant thrombocytopenia, and to maximize synergy with our UOl partners at Childrens Hospital of Philadelphia. Towards this goal we propose a multifaceted program with 4 Aims, with each aim involving two or more investigators from the FHCRC/UW Consortium. In Aim 1, Drs Fero, Paddington and Torok-Storb will generate molecular profiles of functionally defined progenitors in the stem cell to platelet pathway from mouse, dog, and man. These three experimental models have complementary strengths that allow for a comprehensive approach including a robust preclinical in vivo model that can predict clinical outcomes. In Aim 2 these same investigators will gene modify the defined progenitor cells to express lineage-stage-specific reporters for use in a high content, high through put siRNA screening assays to identify changes in the microenvironment that will control progenitor fate. A third Aim will test the proliferation and differentation potential of distinct progenitor subsets in response to conditionally activated signaling molecules. For this purpose Drs Blau and Emery will use signaling molecule derivatives that can be activated in response to small molecule drugs called chemical inducers of dimerization (CIDs). In Aim 4, Drs Kiem and Blau will exploit the canine model of thrombocytopenia to test gene products identified in Aim 2, and cell products expanded in Aim 3 to improve the platelet count in vivo. These in vivo studies in the dog model will establish the safety and efficacy of these therapies in a highly relevant preclinical model