Nkx2.2 in Pancreatic Development: The Role of the NK2-SD Domain

Nkx2.2 在胰腺发育中：NK2-SD 结构域的作用

• 批准号: 8470643
• 负责人: Joshua Adam Levine
• 金额: $ 2.62万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8470643
• 关键词: Alanine; Amino Acids; Animals; Beta Cell; Blood Glucose; Cell Differentiation process; Cells; D Cells; DNA Binding; Development; Diabetes Mellitus; Ductal; Embryonic Development; Endocrine; Epithelial; Evolution; Family member; Functional disorder; Gene Expression Profiling; Generations; Genes; Gland; Glucagon; Gluconeogenesis; Hormonal; Human; In Vitro; Insulin; Investigation; Islet Cell; Islets of Langerhans; Knockout Mice; Knowledge; Laboratories; Maintenance; Mediating; Medical; Metabolic; Molecular; Mono-S; Mus; Mutant Strains Mice; Mutate; Mutation; Nkx-2.2 protein; Oral; Pancreas; Pancreatic Polypeptide; Pharmaceutical Preparations; Phenotype; Play; Point Mutation; Population; Production; Proteins; Protocols documentation; Regulation; Regulatory Pathway; Replacement Therapy; Role; Structure; TAC1 gene; Time; Transcriptional Regulation; Transplantation; blood glucose regulation; cell type; diabetic patient; embryonic stem cell; endocrine pancreas development; ghrelin; glycogenolysis; homeodomain; improved; in vivo; islet; pancreas development; postnatal; promoter; protein protein interaction; response; stem cell differentiation; stem cell technology; transcription factor

DESCRIPTION (provided by applicant): The endocrine pancreas, composed of the islets of Langerhans, is responsible for the maintenance of blood glucose homeostasis. Several cell types comprise the islets and include glucagon-producing . cells, insulin- producing ¿ cells, somatostatin-producing d cells, pancreatic polypeptide-producing PP cells, and ghrelin- producing e cells. Diabetes mellitus is associated with a loss of insulin-producing ¿ cells. Current medical treatment is focused on management of blood glucose levels through insulin replacement as well as oral medications that facilitate insulin release, inhibit gluconeogenesis, and inhibit glycogenolysis. However, in 2000, it was determined that islets can be successfully transplanted into diabetic patients using cadaveric islets. Although cell replacement therapies have been successful, the paucity of donor islets has limited its application and has led to the need to create islets in the laboratory using stem cell technologies. Current stem cell differentiation protocols have been adapted and improved in response to studies of normal mouse pancreas development, however complete ¿ cell differentiation has yet to be achieved. Thus, continued investigation into normal pancreas development will be of utmost importance for creating better in vitro ¿ cell differentiation protocols for the generation of transplantable cells. Nkx2.2 is a homeodomain transcription factor that is essential for the production of several islet cell types. Nkx2.2 null mice do not form ¿ cells and have reduced numbers of a and PP cells. Instead, the Nkx2.2 null islets are filled with ghrelin cells, the predominant mono-hormonal islet cell population that forms in the ES cell differentiation protocols. Therefore, knowledge of Nkx2.2 function and regulation will be important for the development of proper islet cell differentiation protocols. Studies from the Sussel lab have indicated that Nkx2.2 functions as an activator and a repressor at different developmental time points and in different cellular contexts. At this time, the functional structure of the Nkx2.2 protein is not well characterized, although three domains have been described, including the DNA binding homeodomain, the groucho co-repressor interaction domain (TN) and the NK2-specific domain (NK2-SD), which is highly conserved amongst family members and across species, but its function is unknown. Despite its high homology, the function of the NK2-SD domain is unknown. Characterization of the function of the NK2- SD domain during pancreas development will facilitate the development of optimized ¿ cell differentiation protocols. Specific aims: 1. To determine whether the highly conserved Nkx2.2 NK2-SD domain mediates Nkx2.2 function in vivo, I will investigate the phenotypic changes associated with Nkx2.2NK2-SD mutant mice during embryonic development and in postnatal animals. 2. To understand the mechanism by which the NK2-SD domain influences Nkx2.2 mediated transcriptional regulation, I will characterize the DNA binding and transcriptional activities of the NK2-SD domain on candidate Nkx2.2 target promoters.

描述（由应用程序提供）：由兰格汉斯胰岛组成的内分泌胰腺负责维持血糖稳态。几种细胞类型包括胰岛，包括产生胰高血糖素。细胞，产生胰岛素的细胞，产生生长抑素的D细胞，​​产生胰腺多肽的PP细胞以及产生生长素蛋白的E细胞。糖尿病与产生胰岛素的细胞丧失有关。当前的医疗侧重于通过胰岛素替代品以及促进胰岛素释放，抑制糖节生成和抑制糖基溶解的口服药物来治疗血糖水平。但是，在2000年，确定可以使用尸体胰岛成功将胰岛成功移植到糖尿病患者中。尽管细胞替代疗法已经成功，但供体胰岛的匮乏限制了其应用，并导致需要使用干细胞技术在实验室中创建胰岛。当前的干细胞分化方案已通过对正常小鼠胰腺发育的研究进行了调整和改进，但是尚未实现完整的细胞分化。这是为正常胰腺发育的持续投资对于为生成可移植细胞的产生更好的体外细胞分化方案至关重要。 NKX2.2是一种同源域转录因子，对于生产几种胰岛细胞类型至关重要。 NKX2.2无效小鼠不形成细胞，并且A和PP细胞的数量减少。取而代之的是，NKX2.2无效的胰岛充满了生长素蛋白细胞，Ghrelin细胞是在ES细胞分化方案中形成的主要单激素胰岛细胞群。因此，NKX2.2功能和调节的知识对于开发适当的胰岛细胞分化方案将很重要。苏塞尔实验室的研究表明，在不同的发育时间点和不同的细胞环境下，NKX2.2充当激活剂和复制品。目前，尽管已经描述了三个结构域，包括DNA结合综合域，Groupo共抑制剂相互作用域（TN）和NK2特异性结构域（NK2-SD），但在家庭中和跨种类中高度保守，但它的功能是一无所知。尽管具有很高的同源性，但NK2-SD域的功能尚不清楚。胰腺发育过程中NK2-SD结构域功能的表征将有助于开发优化的细胞分化方案。具体目的：1。为了确定高度组成的NKX2.2 NK2-SD结构域是否介导了体内NKX2.2功能，我将研究与NKX2.2NK2-SD突变小鼠在胚胎发育过程中和产后动物中与NKX2.2NK2-SD突变小鼠相关的表型变化。 2。了解NK2-SD域影响NKX2.2介导的转录调控的机制，我将表征NK2-SD域对候选NKX2.2目标启动子的DNA结合和转录活性。