Epigenetic regulation by microRNA of MDS pathogenesis

MicroRNA对MDS发病机制的表观遗传调控

• 批准号: 9096068
• 负责人: Keisuke Ito
• 金额: $ 25.05万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE, INC
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9096068
• 关键词: 3' Untranslated Regions; Ablation; Affect; Attenuated; Biogenesis; Bioinformatics; Biological Assay; Bone Marrow Cells; Cell Line; Cell Proliferation; Cell physiology; Cells; Clinic; Clinical; Clinical Data; Clinical Trials; Custom; DNA Methylation; Data; Data Set; Disease; Down-Regulation; Dysmyelopoietic Syndromes; Ectopic Expression; Epigenetic Process; Event; Evolution; Exhibits; Gene Targeting; Genes; Genetic; Goals; Health; Hematologic Neoplasms; Hematology; Hematopoiesis; Hematopoietic; Hematopoietic Stem Cell Transplantation; Hematopoietic System; Hematopoietic stem cells; Human; Hydroxylation; In Vitro; Ineffective Hematopoiesis; Injury; Knockout Mice; Lead; Leukemic Cell; Link; Luciferases; Maintenance; Malignant - descriptor; Messenger RNA; MicroRNAs; Molecular; Molecular Abnormality; Multiple Myeloma; Mus; Myeloid Leukemia; Myeloproliferative disease; Nuclear; Oncogenic; Onset of illness; Outcome; Pathogenesis; Pathology; Pathway interactions; Patients; Penetrance; Personal Satisfaction; Phenotype; Play; Porifera; Pre-Clinical Model; Proteins; Proto-Oncogenes; Regulation; Regulatory Element; Reporter; Repression; Research; Research Design; Role; Safety; Sampling; Specimen; Stem cells; Supportive care; Survival Rate; Techniques; Testing; Therapeutic; Time; Tissues; Transgenic Mice; Transplantation; Untranslated RNA; Work; Xenograft Model; blood treatment; cohort; effective therapy; epigenetic regulation; gene translocation; genetic manipulation; genome-wide; in vivo; leukemia; leukemogenesis; mouse model; novel; novel therapeutic intervention; oncology; overexpression; pre-clinical trial; programs; reduce symptoms; self-renewal; stem; stem cell biology; stem cell niche; therapeutic target; tumorigenesis

DESCRIPTION (provided by applicant): Myelodysplastic syndrome (MDS) is an incurable stem cell disorder that often progresses to myeloid leukemia. An abnormal epigenetic modulation has been highlighted as playing a crucial part in the pathogenesis, progress, and evolution of this disorder. To date, effective therapy for MDS has proved elusive, with supportive care used to ameliorate symptoms, and hematopoietic stem cell transplantation the only available curative option. MicroRNAs have recently been implicated in hematological malignancies through their inhibition of the expression of specific target genes. In this context, we have identified an oncogenic microRNA that enhances the self-renewal of stem cells and remodels the epigenetic landscape toward hematological malignancies. To better understand through its activity the key pathways involved in stem cell biology and MDS pathogenesis, we propose the following Specific Aims: 1. Determine how TET2 directly contributes to function of an oncogenic microRNA in hematopoiesis We have generated transgenic mice conditionally expressing this newly-identified oncogenic microRNA in the hematopoietic compartment, which in turn exhibits lower levels of ten-eleven translocation gene 2 (TET2) and global 5-hydroxymethylcytosine than control cells. Bioinformatics analyses have consistently identified TET2 as a potential target of this microRNA, whose expression was directly anti-correlated with the levels of TET2 in our large-cohort data set of patients with MDS, leading us to hypothesize that TET2 is its key target. The current proposal aims to elucidate the effect of ectopic expression of TET2 on the hematopoietic phenotypes induced by this microRNA both in vivo and in vitro. We expect our studies will provide a rationale for the therapeutic potential of targeting TET2 for the treatment of hematological malignancies. 2. Test the therapeutic potential of microRNA inhibition in preclinical models of MDS. We have shown a direct correlation between aberrant expression of this microRNA and poor MDS survival rates. Our preliminary findings demonstrated in vitro that blocking this microRNA reduces leukemogenicity in mouse primary leukemic cells and in human leukemia cell lines, accompanied by elevation of TET2, with minimal injury to normal murine hematopoiesis. In this aim, we propose to assess the safety and efficacy of inhibition of microRNA in human primary leukemia samples. We will integrate these findings with the data of ongoing pre-clinical trials in faithful mouse models of myelodysplastic syndrome, and will finally explore the potential to initiate formal clinical trial towards effective eradication of myelodysplastic syndrome. 3. To elucidate mechanistically the key target genes regulated by the microRNA-TET2 pathway: To further understand the consequences of repression of TET2 protein by the microRNA in hematopoiesis, we will examine the effects of aberrant microRNA-TET2 cross-talk on putative targets of TET2 protein. We will focus our analysis on the genetic manipulation of these genes, both in vivo and in vitro, in murine hematopoietic stem cells from transgenic mice, to observe the subsequent effects on MDS pathogenesis induced by microRNA. These proposed studies will not only identify microRNA as a potent proto-oncogene, but will also define aberrations in the microRNA-TET2 regulatory network as one of the most frequent events in hematological malignancies, with important therapeutic implications. This work will be conducted with the support of the following experts; Drs. David E. Avigan (Hematology/Oncology), Jan Vijg (Genetics, Epigenetics and microRNA biogenesis), Julie Teruya-Feldstein (Hemato-pathology), and Toshio Suda (Stem Cells). Importantly, Dr. Paul S. Frenette (Stem Cell niche) is closely supporting our research program along with Dr. Arthur Skoultchi (Epigenetic reprogramming in Hematology).

描述（由申请人提供）：骨髓增生异常综合征（MDS）是一种无法治愈的干细胞疾病，通常会进展为骨髓性白血病。异常的表观遗传调节已被强调在这种疾病的发病机制、进展和进化中发挥着至关重要的作用。迄今为止，MDS 的有效治疗方法难以捉摸，只能通过支持治疗来改善症状，而造血干细胞移植是唯一可用的治疗选择。最近，MicroRNA 通过抑制特定靶基因的表达而与血液恶性肿瘤有关。在这种背景下，我们发现了一种致癌的 microRNA，它可以增强干细胞的自我更新，并重塑血液恶性肿瘤的表观遗传景观。为了通过其活性更好地了解干细胞生物学和 MDS 发病机制中涉及的关键途径，我们提出以下具体目标： 1. 确定 TET2 如何直接促进造血中致癌 microRNA 的功能 我们已经培育出转基因小鼠，在造血室中有条件地表达这种新鉴定的致癌 microRNA，从而表现出较低水平的 10-11 易位基因 2 (TET2) 和全局 5-羟甲基胞嘧啶比对照细胞高。生物信息学分析一致认为 TET2 是该 microRNA 的潜在靶标，其表达与 MDS 患者大队列数据集中的 TET2 水平直接反相关，这使我们推测 TET2 是其关键靶标。目前的提案旨在阐明 TET2 的异位表达对该 microRNA 在体内和体外诱导的造血表型的影响。我们期望我们的研究将为靶向 TET2 治疗血液恶性肿瘤的治疗潜力提供理论依据。 2. 测试 microRNA 抑制在 MDS 临床前模型中的治疗潜力。我们已经证明这种 microRNA 的异常表达与 MDS 存活率低之间存在直接相关性。我们的初步研究结果表明，在体外阻断这种 microRNA 可降低小鼠原代白血病细胞和人白血病细胞系的致白血病性，并伴有 TET2 升高，同时对正常小鼠造血功能的损害最小。为此，我们建议评估人类原发性白血病样本中抑制 microRNA 的安全性和有效性。我们将把这些发现与正在进行的骨髓增生异常综合征忠实小鼠模型的临床前试验数据相结合，并最终探索启动正式临床试验以有效根除骨髓增生异常综合征的潜力。 3. 从机制上阐明 microRNA-TET2 通路调控的关键靶基因：为了进一步了解 microRNA 在造血过程中抑制 TET2 蛋白的后果，我们将检查异常的 microRNA-TET2 串扰对 TET2 蛋白假定靶标的影响。我们将重点分析转基因小鼠造血干细胞中这些基因的体内和体外遗传操作，以观察 microRNA 对 MDS 发病机制的后续影响。这些拟议的研究不仅将确定 microRNA 是一种有效的原癌基因，还将将 microRNA-TET2 调控网络中的畸变定义为血液恶性肿瘤中最常见的事件之一，具有重要的治疗意义。这项工作将在以下专家的支持下进行；博士。 David E. Avigan（血液学/肿瘤学）、Jan Vijg（遗传学、表观遗传学和 microRNA 生物发生）、Julie Teruya-Feldstein（血液病理学）和 Toshio Suda（干细胞）。重要的是，Paul S. Frenette 博士（干细胞领域）与 Arthur Skoultchi 博士（血液学表观遗传重编程）密切支持我们的研究项目。