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

• 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
• 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

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 垂体前垂体中体育体和乳酸谱的差异构成高度 哺乳动物细胞分化的信息丰富，医学上相关且特征良好的模型。 值得注意的是，两个谱系的分化取决于相同的垂体特异性的活性 转录因子，PIT-1（POU1-F1）。定义两个谱系中每个谱系的地标基因，例如生长 激素（GH）和催乳素（PRL）直接控制PIT-1依赖的顺式调节元件。损失 PIT-1的表达导致小鼠和人类的两种细胞类型都没有两种细胞类型 随之而来的组合激素缺乏综合征。尽管PIT-1对开发至关重要 垂体前垂体的功能，激活差异化的机制和途径 尚不清楚体长和乳酸谱的维持。我们假设那个坑-1， 与差异表达的转录因子一起作用，控制了 通过与谱系定义的顺式调节元件结合，体育型和乳糖谱系 范围转录相互作用，组织核小体架构以及定义谱系依赖性三个 尺寸（3D）染色质网络。在AIM 1中，我们检验了Pit-1占用率的假设 人类GH基因座控制区域（HSI）中的增强元素激活一系列时间定义 对于垂体中HGH-N转录的鲁棒和选择性激活至关重要的功能 在乳酸谱系中的躯体及其相互抑制作用。在AIM 2中，我们检验了以下假设 PIT-1驱动谱系差异的能力取决于其与协同转录因子的相互作用。 候选因子通过对原发流量分类的比较转录组分析来鉴定 和乳糖，并通过一组引人注目的功能测定验证。在AIM 3中，我们检验假设 在整个乳腺癌和乳糖中建立了3D染色质相互作用的不同网络 集成和协调谱系特异性基因激活和抑制程序的基因组，并且这些 3-D体系结构取决于谱系特定的PIT-1动作。这三个目标均基于分析 从生理上完整的野生型或转基因小鼠系的垂体中分离出来的原代细胞。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基础 激素表达中的表型变化，鉴定遗传和获得的内分泌中的因果突变 疾病，并突出显示新的治疗干预措施的目标。此外，该程序将建立一个 具有里程碑意义的模型中哺乳动物开发的范式，并作为研究模板 在广泛的实验环境中的分化和基因组调节。