Cross-talk mechanisms between RUNX1 and inflammatory signals impacting functions of stem and progenitors in Familial Platelet Disorder.

项目摘要 实体瘤的生殖系癌症易感性已得到充分证实。曾被认为是罕见的事件， 骨髓性恶性肿瘤的易感性现在被包括在最新的白血病分类方案中， 世界卫生组织。因此，预计更多的患者将被识别为可以产生 一直害怕家人患上白血病鉴于最好的治疗方法是预防， 从癌前病变阶段过渡到显性疾病阶段的重要因素是建立 指导方针，以监测和治疗这些病人。在许多白血病易感综合征中， 单等位基因RUNX 1生殖系突变引起的家族性血小板疾病（FPD）。RUNX 1突变 FPD导致出血性疾病、血小板计数降低和功能障碍。FPD是最常见的形式之一 遗传性骨髓性恶性肿瘤，患者在中位年龄时有~40%的终生机会发展为白血病。 年龄33岁。然而，向显性白血病的转变伴随着继发性突变的获得， the complete完整mechanism机制of disease疾病transformationis unknown未知.有趣的是，FPD患者表现出不同的 过敏，如皮肤湿疹，表明炎症增加在驱动白血病中的可能作用 发展因此，我们认为炎症应激促进白血病的发生和发展， FPD为了验证这一点，我们使用原代FPD骨髓细胞进行了一系列实验。我们观察到 FPD造血干细胞和祖细胞（HSPC）显示髓样偏向分化和增加的集落 形成能力差，巨核细胞分化落后。健康人单细胞转录组分析 和FPD骨髓细胞证实了祖细胞的偏斜分化，并鉴定了 与健康干细胞相比，FPD中的炎症反应途径。同样，我们发现 骨髓龛中的炎性细胞因子，包括间充质基质细胞。所以我 假设RUNX 1突变介导的HSPC和炎症改变之间的相互作用 微环境促进FPD干细胞和祖细胞的骨髓生长和分化缺陷 细胞为了解决这一假设，在目标1中，我将评估炎症应激对生长的影响， FPD和健康HSPC的分化。我将使用遗传或药物抑制方法， 剖析炎症应激影响FPD HSPC功能的机制。然后，我将确定 使用CUT&Tag实验，这些效应是否由RUNX 1直接调节。在目标2中，我将确定 RUNX 1突变骨髓基质细胞对FPD和健康HSPCs功能的影响 建立了三维共培养方法。然后，我将使用一种独特的小鼠模型， 突变，以确定骨髓小生境对干细胞生长和分化缺陷的作用。的 这项研究的结果将提高疾病生物学的现有知识，并有助于我的长期研究。 目标是确定新的靶向治疗方法，用于治疗甚至减轻疾病的发生。

PROJECT SUMMARY Germline cancer predispositions are well established for solid tumors. Once thought to be a rare event, predispositions to myeloid malignancies are now included in the latest leukemia classification scheme from the World Health Organization. Thus, more patients are expected to be recognized as carriers which can create a constant fear of developing leukemia in their families. Given the best treatment is prevention, understanding the important factors in transitioning from pre-malignant to overt disease stage is fundamental in establishing guidelines for monitoring and treatment of such patients. Of many leukemia predisposition syndromes, we focus on familial platelet disorders (FPD) caused by monoallelic RUNX1 germline mutations in. RUNX1-mutations in FPD lead to bleeding disorders, lower counts and dysfunction of platelets. FPD is one of the most common forms of inherited myeloid malignancies, and patients have ~40% life-long chance of developing leukemia at median age of 33 years. The transition to overt leukemia is accompanied by acquisition of secondary mutations, though the complete mechanism of disease transformationis unknown. Intriguingly, FPD patients manifest with different allergies such as skin eczema, indicating the possible role of increased inflammation in driving leukemia development. Therefore, we propose that inflammatory stress facilitates leukemia initiation and progression in FPD. To test this, we performed series of experiments using primary FPD bone marrow cells. We observed that FPD hematopoietic stem and progenitors (HSPCs) show myeloid biased differentiation and increased colony formation ability, while fall behind in megakaryocyte differentiation. Single cell transcriptome analysis of healthy and FPD bone marrow cells confirmed the skewed differentiation of progenitors and identified enrichment of inflammatory response pathways in FPD compared to healthy stem cells. Consistently, we found upregulation of inflammatory cytokines in the bone marrow niche, including from mesenchymal stromal cells. Therefore, I hypothesize that a cross-talk between RUNX1-mutations mediated changes in HSPCs and inflammatory microenvironment promotes myeloid growth and differentiation defects in FPD stem and progenitor cells. To address this hypothesis, in Aim 1, I will evaluate the impact of inflammatory stress on growth and differentiation of FPD and healthy HSPCs. I will use the genetic or pharmacological inhibition approaches to dissect the mechanism by which inflammatory stress impacts the functions of FPD HSPCs. Then, I will identify whether these effects are directly regulated by RUNX1 using CUT&Tag experiments. In Aim 2, I will determine the effect of RUNX1-mutated bone marrow stromal cells on the function of FPD and healthy HSPCs using newly established 3D co-culture methods. Then, I will use a unique mouse model with germline Runx1-hetrozygous mutation to determine the role of bone marrow niche on stem cell growth and differentiation defects. The outcomes of this study will improve the existing knowledge of disease biology and contribute to my long-term goal of identifying new targeted therapies for the treatment and even attenuating disease initiation.