Mapping the transcriptional regulatory circuits of human hematopoiesis

描述(申请人提供)：白血病是所有种族和民族中最常见的10种癌症之一，其特征是致癌转录因子的异常活性导致造血分化受损。对控制造血谱系的转录调控网络的系统表征将使我们能够了解致病变化的作用，改进诊断，并发现新的治疗靶点。我们实验室最近对人类造血的研究表明，数百种转录因子参与协调造血，其中包括30种在白血病易位中发现的转录因子。然而，由于目前检测方法的局限性(如染色质免疫沉淀分析，CHIP)，破译这些转录因子与其靶标之间的直接联系仍然是一个难以实现的目标。在这里，我将利用我们实验室开发的一种新的、高通量的芯片序列分析，建立一个全面的物理调控网络，包括四个主要的终末分化的人类造血细胞群体中的100个谱系特异性和恶性肿瘤相关的转录因子。我将使用计算算法来构建一个预测性的功能调控模型，该模型将物理结合网络与其控制的基因表达谱相结合。结合从患者样本中测量的基因表达谱，该模型将用于预测恶性转录调控电路。最后，我将使用选定的关键转录因子的敲除表达谱来验证和改进他的模型。这项研究将极大地提高我们对造血分化和白血病发病机制的理解，走向个性化的诊断和治疗。 公共卫生相关性：白血病发病机制的一个标志是癌基因转录因子的异常表达，导致造血分化受损和癌症的发展。因此，了解正常和恶性造血分化背后的转录调控电路对于改进诊断和治疗非常重要。利用我们实验室开发的一种新颖的高通量染色质免疫沉淀技术，我将提供第一张全面的人类造血分化转录调控图，特别是已被确认为白血病异常转录因子的转录调控图；我们相信，这项研究将大大增强我们对造血分化和白血病发病机制的理解。

DESCRIPTION (provided by applicant): Leukemia, one of the top 10 most frequently occurring cancers in all races and ethnicities, is characterized by the aberrant activity of oncogenic transcription factors that lead to impaired hematopoietic differentiation. Systematic characterization of the transcriptional regulatory network controlling the hematopoietic lineage will enable us to understand the role of pathogenic changes, improve diagnosis, and discover new therapeutic targets. Very recent studies in human hematopoiesis from our laboratory show that hundreds of transcription factors participate in orchestrating hematopoiesis, including 30 that were found in translocations in leukemia. However, due to the limitations of current assays (e.g. chromatin immunoprecipitation assay, ChIP), deciphering the direct connections between these transcription factors and their targets remains an elusive goal. Here, I will build a comprehensive physical regulatory network of 100 lineage specific and malignancy-related transcription factors in the four main terminally differentiated human hematopoietic cell populations, by employing a novel, high throughput ChIP-seq assay developed by our laboratory. I will use computational algorithms to construct a predictive functional regulatory model that integrates the physical binding network with the gene expression profiles it controls. Together with gene expression profiles measured from patient's samples, the model will be used to predict malignant transcriptional regulatory circuits. Finally, I will validate and refine he model using expression profiles from knockdowns of selected key transcription factors. This study will substantially enhance our understanding of hematopoietic differentiation and leukemia pathogenesis, towards personalized diagnoses and therapeutics. PUBLIC HEALTH RELEVANCE: A hallmark of the pathogenesis of leukemia is the aberrant expression of oncogenic transcription factors that leads to impaired hematopoietic differentiation and the development of cancer. Understanding the transcriptional regulatory circuits underlying normal and malignant hematopoietic differentiation is thus important for improved diagnoses and therapies. Utilizing a novel, high throughput chromatin immunoprecipitation technology developed by our laboratory, I will provide the first comprehensive transcriptional regulatory map of the human hematopoietic differentiation, particularly of transcription factors that has been identified as aberrant in leukemia; we believe, this study will substantially enhance our understanding of hematopoietic differentiation and leukemia pathogenesis.