Mapping the transcriptional regulatory circuits of human hematopoiesis

描述（由申请人提供）：白血病是所有种族和民族中十大最常见的癌症之一，其特征是致癌转录因子的异常活性导致造血分化受损。系统表征控制造血谱系的转录调控网络将使我们能够了解致病变化的作用，提高诊断水平，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造血，包括30种在白血病易位中发现的转录因子。然而，由于当前检测方法（如染色质免疫沉淀测定，ChIP）的局限性，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捉摸的目标。在这里，我将建立一个全面的物理调控网络，100谱系特异性和恶性肿瘤相关的转录因子在四种主要的终末分化的人造血细胞群，通过采用一种新的，高通量的ChIP-seq分析由我们的实验室开发。我将使用计算算法来构建一个预测功能调节模型，该模型将物理结合网络与其控制的基因表达谱集成在一起。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回路。最后，我将使用来自选定关键转录因子敲除的表达谱来验证和完善模型。这项研究将大大提高我们对造血分化和白血病发病机制的理解，朝着个性化诊断和治疗的方向发展。

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.