Mutant p53 rejuvenates aged stem cells through modulating epigenetic regulators

项目摘要/摘要 老年人面临着巨大的血液病负担，包括贫血、克隆性 造血、骨髓增生异常综合征(MDS)和急性髓系白血病(AML)。MD是一组 起源于HSC并经常进展为AML的老年人的血液疾病。而肿瘤中的突变 在老年健康人和MDS患者的血细胞中发现了抑制子P53，突变体的作用 P53在HSC衰老和MDS发病机制中的作用目前尚不清楚。我们最近发现，一些收益- 功能(GOF)突变型P53蛋白通过一种新机制增强HSCs的自我更新能力 涉及到破坏表观遗传途径。我们的目标是研究GOF突变型P53在人类免疫缺陷中的作用。 HSC老化与MDS发病机制的关系，为MDS的治疗寻找新的治疗靶点。我们 假设在老年HSCs中获得特定的GOF P53突变驱动Pre-Pre的发展 白血病造血干细胞具有增强的自我更新能力，从而允许克隆进化和 随后获得导致MDS干细胞形成的突变和/或表观遗传变化。 我们推测，药物抑制对p53突变的合成致死通路将消除药物- 耐药MDS干细胞和改善治疗结果。在这项拟议的研究中，我们将利用 生物化学、遗传学、分子和药理学方法以及人类脊椎动物模型 目的：研究干细胞老化和MDS发生的表观遗传学调控。我们将聘用 无偏见的全基因组方法，包括RNA-SEQ、CHIP-SEQ和DNA甲基化分析，以识别 GOF突变型P53靶向并破译GOF突变型P53如何调节老年HSCs的基因表达。在……里面 此外，我们还将鉴定p53R248W/ASXL1/-小鼠中的MDS干细胞，并阐明其机制。 突变型p53促进MDS干细胞自我更新。此外，我们将识别出 CRISPR-CAS9筛选对人MDS细胞突变型p53的合成杀伤作用。我们的结果将填补一个 关于白血病前造血干细胞和MDS干细胞起源和发展的显著差异 细胞。我们预计这些研究将描绘特定的突变型P53蛋白在老年HSC中的作用。 白血病前HSCs和MDS干细胞，并可能在人类MDS细胞中识别具有p53的新靶点 可能具有治疗潜力的突变，以消除耐药的MDS干细胞。这些结果 可能会为衰老、MDS和癌症研究开辟新的途径。

PROJECT SUMMARY/ABSTRACT Elderly individuals are faced with a significant burden of hematologic diseases, including anemia, clonal hematopoiesis, myelodysplastic syndromes (MDS), and acute myeloid leukemia (AML). MDS are a group of blood diseases of the elderly that initiate in a HSC and frequently progress to AML. While mutations in tumor suppressor p53 are found in the blood cells of aged healthy individuals and in MDS patients, the role of mutant p53 in HSC aging and pathogenesis of MDS are largely unknown. We recently discovered that some gain-of- function (GOF) mutant p53 proteins enhanced the self-renewal potential of HSCs by a novel mechanism involving disruption of epigenetic pathways. Our objective here is to characterize the role of GOF mutant p53 in HSC aging and pathogenesis of MDS and identify novel therapeutic targets for the treatment of MDS. We hypothesize that acquisition of specific GOF p53 mutations in aged HSCs drives the development of pre- leukemic hematopoietic stem cells with enhanced self-renewal capability, thereby allowing clonal evolution and subsequent acquisition of mutations and/or epigenetic changes that lead to the formation of MDS stem cells. We speculate that pharmacological inhibition of pathways synthetic lethal to p53 mutations will eliminate drug- resistant MDS stem cells and improve treatment outcome. In this proposed research, we will utilize biochemical, genetic, molecular, and pharmacological approaches as well as vertebrate models of human MDS to investigate the epigenetic regulation of stem cell aging and MDS development. We will employ unbiased genome-wide approaches, including RNA-seq, ChIP-seq, and DNA methylation assays, to identify GOF mutant p53 targets and decipher how GOF mutant p53 regulates gene expression in aged HSCs. In addition, we will characterize MDS stem cells in p53R248W/+Asxl1+/- mice and elucidate the mechanism by which mutant p53 enhances MDS stem cell self-renewal. Further, we will identify genes and pathways that are synthetic lethal to mutant p53 in human MDS cells using CRISPR-Cas9 screening. Our results will fill a significant gap regarding the origin and development of pre-leukemic hematopoietic stem cells and MDS stem cells. We anticipate that these studies will delineate the effects of specific mutant p53 proteins in aged HSCs, pre-leukemic HSCs, and MDS stem cells, and will likely identify novel targets in human MDS cells with p53 mutations that may have therapeutic potential for eliminating drug-resistant MDS stem cells. These outcomes would likely open new avenues for aging, MDS, and cancer research.