Determinants of Human Growth Hormone Expression and Pituitary Cell Differentiation

人类生长激素表达和垂体细胞分化的决定因素

基本信息

批准号：
9313887
负责人：
STEPHEN Aaron LIEBHABER
金额：
$ 52.01万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-07-15 至 2019-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9313887
关键词：
3-Dimensional Adult Anterior Pituitary Gland Architecture Binding Binding Sites Biochemical Biological Assay Biomedical Research Cell Differentiation process Cell Nucleus Cells Chromatin Critical Pathways Defect Development Developmental Biology Diagnosis Dimensions Disease Embryo Endocrine System Diseases Endocrine system Enhancers Environment Epigenetic Process Funding Gene Activation Gene Expression Gene Expression Regulation Genes Genetic Enhancer Element Genetic Transcription Genome Goals Hormones Human Informatics Inherited Investigation Laboratories Link Locus Control Region Maintenance Mediating Medical Modeling Mus Mutation Nucleosomes Organogenesis Pathologic Pathway interactions Pattern Phenotype Physiological Pituitary Gland Population Process Prolactin Public Health Regulation Regulator Genes Regulatory Element Regulatory Pathway Repression Role Series Somatotropin Somatropin Structure Syndrome System Technology Testing Therapeutic Intervention Trans-Activators Transcriptional Activation Transcriptional Regulation Transgenic Mice Transgenic Model Variant Work base cell type chromatin modification comparative differential expression gene repression genome-wide health knowledge hormone deficiency in vivo new therapeutic target novel programs promoter transcription factor transcription factor Pit-1 transcriptome

项目摘要

Abstract The divergence of the somatotrope and lactotrope lineages in the anterior pituitary constitutes a highly informative, medically relevant, and well-characterized model of mammalian cellular differentiation. Remarkably, the differentiation of both lineages is dependent on the activity of the same pituitary-specific transcription factor, Pit-1 (POU1-F1). Landmark genes defining each of the two lineages, such as Growth Hormone (GH) and Prolactin (Prl), are under direct control of Pit-1 dependent cis-regulatory elements. Loss of Pit-1 expression results in absence of both cell types from the anterior pituitary in mice and humans with consequent combined hormone deficiency syndromes. Despite the central importance of Pit-1 to development and function of the anterior pituitary, the mechanisms and pathways that it activates to drive the differentiation and maintenance of the somatotrope and lactotrope lineages remain unclear. We hypothesize that Pit-1, acting in conjunction with differentially expressed transcription factors, controls the divergence of the somatotrope and lactotrope lineages by binding to lineage-defined cis-regulatory elements, mediating long- range transcriptional interactions, organizing nucleosomal architectures, and defining lineage-dependent three dimensional (3D) chromatin networks. In Aim 1, we test the hypothesis that Pit-1 occupancy at the major enhancer element within the human GH locus control region (HSI) activates a series of temporally-defined functions that are critical to the robust and selective activation of hGH-N transcription in the pituitary somatotrope and its reciprocal repression in the lactotrope lineage. In Aim 2 we test the hypothesis that the ability of Pit-1 to drive lineage divergence depends on its interactions with cooperating transcriptional factor(s). Candidate factors are identified by comparative transcriptome analyses of primary flow-sorted somatotropes and lactotropes and are validated by a set of compelling functional assays. In Aim 3 we test the hypothesis that distinct networks of 3D chromatin interactions are established throughout the somatotrope and lactotrope genomes to integrate and coordinate lineage-specific gene activation and repression programs and that these 3-D architectures are dependent on lineage-specific Pit-1 actions. All three Aims are based on analyses of primary cells isolated from the pituitaries of physiologically intact wild type or transgenic mouse lines. These studies will extend our understanding of pituitary function and will allow us to predict and define the basis for phenotypic variations in hormone expression, identify causative mutations in inherited and acquired endocrine disorders, and highlight targets for novel therapeutic interventions. Furthermore, this program will establish a paradigm of mammalian development in a landmark model and serve as a template for investigations of differentiation and genome regulation in a broad spectrum of experimental settings.

抽象的垂体前叶中生长激素和催乳激素谱系的分歧构成了高度信息丰富、医学相关且特征明确的哺乳动物细胞分化模型。值得注意的是，两个谱系的分化取决于相同垂体特异性的活性转录因子 Pit-1 (POU1-F1)。定义两个谱系的标志性基因，例如生长激素 (GH) 和催乳素 (Prl) 受 Pit-1 依赖性顺式调节元件的直接控制。损失 Pit-1 表达导致小鼠和人类垂体前叶两种细胞类型的缺失随之而来的联合激素缺乏综合征。尽管一号坑对发展至关重要垂体前叶的功能和功能，它激活驱动分化的机制和途径生长素和催乳素谱系的维持和维持仍不清楚。我们假设 Pit-1，与差异表达的转录因子一起作用，控制生长素和催乳素谱系通过与谱系定义的顺式调节元件结合，介导长范围转录相互作用，组织核小体结构，并定义谱系依赖的三个三维（3D）染色质网络。在目标 1 中，我们测试了以下假设：Pit-1 在主要区域的占用率人类 GH 基因座控制区 (HSI) 内的增强子元件激活一系列暂时定义的对于垂体中 hGH-N 转录的稳健和选择性激活至关重要的功能生长激素及其在催乳素谱系中的相互抑制。在目标 2 中，我们检验以下假设： Pit-1 驱动谱系分歧的能力取决于其与协作转录因子的相互作用。通过对初级流分类生长激素的比较转录组分析来鉴定候选因子和催乳素，并通过一系列引人注目的功能测定进行验证。在目标 3 中，我们检验假设在整个生长素和催乳素中建立了不同的 3D 染色质相互作用网络基因组来整合和协调谱系特异性基因激活和抑制程序，并且这些 3-D 架构依赖于谱系特定的 Pit-1 操作。所有三个目标均基于以下分析：从生理完整的野生型或转基因小鼠系的垂体中分离出的原代细胞。这些研究将扩展我们对垂体功能的理解，并使我们能够预测和定义垂体功能的基础激素表达的表型变异，识别遗传性和获得性内分泌的致病突变疾病，并突出新的治疗干预措施的目标。此外，该计划将建立一个具有里程碑意义的模型中哺乳动物发育的范式，并作为研究的模板广泛的实验环境中的分化和基因组调控。