Ing4-deficiency enhances the regenerative capacity of multipotent progenitor cells

项目摘要/摘要。长期造血干细胞(HSCs)能够自我更新和 分化为所有成熟的造血系。这一过程的既定范例涉及 造血干细胞的自我更新和分化为祖细胞。我们提案的主要目标是定义 造血干细胞移植中促进干/祖细胞自我更新的机制 病人。接受造血干细胞移植治疗非恶性疾病和疾病的患者稳步上升 发生在过去20年，但这些患者的存活率在五年内可能低至20%-40% 移植后时期。这表明对这些患者进行改进的造血干细胞移植的需求很大。至 提高了我们对HSC功能和自我更新的认识，我完成了第一次大规模的体内逆转 针对染色质因子的遗传筛选，它通过染色质的变化来调节基因的表达 结构。从这个屏幕上，我们发现了对植物同源多态(PHD)手指和染色质的要求 相关蛋白，Ing4。作为Hbo1染色质重塑复合体的成员，Ing4与靶基因座结合 通过识别H3K4me3标记并增加组蛋白乙酰化的局部水平。Ing4也有 已被证明对NF-κB、c-Myc、HIF1a和P53具有负调控作用。我们对Ing4基因缺陷小鼠的研究表明 Ing4的缺失对骨髓的造血有很大的影响。这些小鼠表现出增加 HSCs水平和多能祖细胞(MPP)的丧失。MPPS的移植表明，虽然有 MPP越少，分化到MPP阶段的细胞就越有能力 与野生型相比，在9个月后表现出非常高的嵌合体水平 移植。我们假设Ing4调节MPP细胞的自我更新特性和Ing4的丢失 结果产生具有激活的干细胞样属性的MPPS。根据这项提案所做的工作将确定 Ing4缺陷的MPP的通路改变，以表征它们是如何恢复功能的 就像造血干细胞一样。如果成功，我们的研究将为重新激活自我更新途径提供一种新的机制。 这可能会为需要这种治疗的患者带来更成功的造血干细胞移植。

Project summary/Abstract. Long-term hematopoietic stem cells (HSCs) are capable of self-renewal and differentiation into all mature hematopoietic lineages. The established paradigm for this process involves the self-renewal and differentiation of HSCs into progenitor cells. The primary goal of our proposal is to define mechanisms to enhance self-renewal in stem and progenitor cells for hematopoietic stem cell transplantation in patients. A steady rise in patients receiving HSC transplants for non-malignant diseases and disorders has occurred over the last two decades, but survival of these patients can be as low as 20-40% in the five year post-transplant period. This suggests a strong need for improved HSC transplants for these patients. To advance our understanding of HSC function and self-renewal, I completed the first large-scale in vivo reverse genetic screen targeting chromatin factors, which regulate gene expression through changes in chromatin structure. From this screen, we found a requirement for the plant homeodoming (PHD) finger and chromatin associated protein, Ing4. As a member of the Hbo1 chromatin remodeling complex, Ing4 binds to target loci through recognition of H3K4me3 marks and increases localized levels of histone acetylation. Ing4 has also been shown to negatively regulate NF-κB, c-Myc, Hif1a, and p53. Our work in Ing4-deficient mice has shown that loss of Ing4 has a dramatic effect on hematopoiesis in the bone marrow. These mice show increased levels of HSCs and a loss of multipotent progenitors (MPPs). Transplantation of MPPs shows that while there are fewer MPPs, the cells that do differentiate to the MPP stage are more capable of robust, long-term reconstitution than their wild-type counterparts, showing very high levels of chimerism up to 9 months post- transplant. We hypothesize that Ing4 regulates self-renewal properties in MPP cells and loss of Ing4 results in MPPs with activated stem cell-like properties. Work done under this proposal will identify the pathways altered in Ing4-deficient MPPs to characterize how they have regained the ability to function like HSCs. If successful, our studies will provide a new mechanism for re-activating self-renewal pathways. This could lead to more successful HSC transplants for patients needing this treatment.