Regulation of Exocrine Pancreatic Progenitors by Ptf1a-p48

Ptf1a-p48 对外分泌胰腺祖细胞的调节

• 批准号: 7591123
• 负责人: Steven D Leach
• 金额: $ 34.34万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7591123
• 关键词: Acinar Cell; BHLH Protein; Biological Assay; Biological Models; Cell Cycle; Cell Differentiation process; Cells; Code; Data; Defect; Development; Diabetes Mellitus; Differentiation and Growth; Dorsal; Elements; Epithelium; Functional RNA; Gene Expression; Gene Targeting; Genes; Goals; Growth; In Vitro; Laboratories; Late Effects; Lead; Malignant neoplasm of pancreas; Mediating; MicroRNAs; Morphogenesis; Mus; Mutation; Notch Signaling Pathway; Pancreas; Pancreatic Bud; Pattern; Phenotype; Play; Process; Regulation; Replacement Therapy; Research; Resources; Reverse Transcriptase Polymerase Chain Reaction; Role; Staging; Stem cells; Testing; Therapeutic; Undifferentiated; Work; Zebrafish; base; cell growth; design; gain of function; genome wide association study; genome-wide; human DICER1 protein; in vivo; loss of function; migration; mutant; novel; pancreas development; progenitor; programs; protein expression; public health relevance; research study; transcription factor

DESCRIPTION (provided by applicant): Pancreatic progenitor cells represent an important resource for cell replacement therapy in diabetes, and may also represent the cell-of-origin for pancreatic cancer. Among the many transcription factors regulating pancreatic development and differentiation, expression of the basic helix-loop-helix transcription factor, ptf1a-p48, represents the defining feature of pancreatic progenitor cells. Several laboratories, including our own, have identified distinct early and late effects of ptf1a-p48 during pancreatic development. Early in development, ptf1a-p48 is widely expressed in the emerging pancreatic epithelium, where it is required for specification of pancreatic identity, as well as for early growth and morphogenesis. Later in development, ptf1a-p48 becomes restricted to the exocrine compartment, where it induces cell cycle exit and acinar cell differentiation. However, the mechanisms by which ptf1a-p48 exerts its different developmental stage-specific effects remain unknown. We now propose to comprehensively characterize both early and late ptf1a-p48 functions, taking advantage of our unique ability to study pancreas development in both mouse and zebrafish. This work will be based on the following central hypotheses: First, that the early and late effects of ptf1a-p48 on pancreatic development are mediated through entirely different sets of ptf1a-p48 target genes; second, that different structural domains of the ptf1a-p48 molecule may be required for induction of these early and late effects; and third, that ptf1a-p48 target genes may include both coding and non-coding elements, including functionally important microRNA's. To test these hypotheses, the following Specific Aims will be pursued: 1) To identify discrete domains of the ptf1a-p48 molecule responsible for mediating its developmental stage-specific effects on pancreatic development, using newly developed in vivo assays; 2) To identify novel ptf1a-p48 target genes through genome-wide ChIP-on-chip analysis, and determine gain-of-function and loss-of-function phenotypes associated with altered expression of these genes; and 3) To identify and functionally characterize novel ptf1a-p48-regulated microRNA's in developing mouse and zebrafish pancreas. Together, these studies will determine the mechanisms by which ptf1a-p48 exerts its multiple influences in developing mouse and zebrafish pancreas. In so doing, it is likely that we will also identify important new regulators of pancreatic specification, morphogenesis and differentiation. By clarifying the role of this important transcription factor in regulating the pancreatic progenitor pool, these studies will contribute to the eventual therapeutic manipulation of these cells in the context of pancreatic cancer and diabetes. Public Health Relevance: Pancreatic progenitor cells represent an important resource for cell replacement therapy in diabetes, and may also represent the cell-of-origin for pancreatic cancer. Studies in this proposal focus on how Ptf1a-p48, a pancreatic transcription factor, regulates the initial specification, growth and differentiation of pancreatic progenitor cells. We have recently completed two genome-wide screens for genes that may act downstream of Ptf1a-p48. In so doing, we have identified a number of additional coding and non-coding genes that may play important roles in regulating the pancreatic progenitor pool. Using both mouse and zebrafish model systems, we now plan to functionally characterize these novel Ptf1a-p48 target genes. By better clarifying how Ptf1a-p48 regulates progenitor cell growth and differentiation, these studies will contribute to the eventual therapeutic manipulation of pancreatic progenitors in the context of pancreatic cancer and diabetes.

描述（由申请人提供）：胰腺祖细胞是糖尿病细胞替代疗法的重要来源，也可能是胰腺癌的起源细胞。在调节胰腺发育和分化的许多转录因子中，碱性螺旋-环-螺旋转录因子ptf 1a-p48的表达代表了胰腺祖细胞的定义特征。几个实验室，包括我们自己的实验室，已经确定了ptf 1a-p48在胰腺发育过程中不同的早期和晚期作用。在发育的早期，ptf 1a-p48在新生胰腺上皮中广泛表达，在那里它是胰腺特性的特化以及早期生长和形态发生所必需的。在发育后期，ptf 1a-p48被限制在外分泌区室，在那里它诱导细胞周期退出和腺泡细胞分化。然而，ptf 1a-p48发挥其不同发育阶段特异性作用的机制仍不清楚。我们现在建议全面表征ptf 1a-p48的早期和晚期功能，利用我们独特的能力来研究小鼠和斑马鱼的胰腺发育。这项工作将基于以下中心假设：第一，ptf 1a-p48对胰腺发育的早期和晚期效应是通过完全不同的ptf 1a-p48靶基因组介导的;第二，ptf 1a-p48分子的不同结构域可能需要诱导这些早期和晚期效应;第三，ptf 1a-p48靶基因可能包括编码和非编码元件，包括功能上重要的microRNA。为了验证这些假设，将追求以下具体目标：1）使用新开发的体内测定法来鉴定ptf 1a-p48分子的负责介导其对胰腺发育的发育阶段特异性作用的离散结构域; 2）通过全基因组ChIP-on-chip分析鉴定新的ptf 1a-p48靶基因，并确定与这些基因的表达改变相关的功能获得和功能丧失表型;和3）鉴定和功能表征发育中的小鼠和斑马鱼胰腺中的新型ptf 1a-p48调节的microRNA。总之，这些研究将确定ptf 1a-p48在小鼠和斑马鱼胰腺发育中发挥多重影响的机制。在这样做的过程中，我们很可能还将确定胰腺特化、形态发生和分化的重要新调节因子。通过阐明这种重要的转录因子在调节胰腺祖细胞库中的作用，这些研究将有助于在胰腺癌和糖尿病的背景下对这些细胞进行最终的治疗操作。 公共卫生相关性：胰腺祖细胞是糖尿病细胞替代疗法的重要来源，也可能是胰腺癌的起源细胞。本研究主要关注胰腺转录因子Ptf 1a-p48如何调控胰腺祖细胞的初始特化、生长和分化。我们最近完成了两个全基因组筛选可能作用于Ptf 1a-p48下游的基因。在这样做的过程中，我们已经确定了一些额外的编码和非编码基因，可能在调节胰腺祖细胞池中发挥重要作用。使用小鼠和斑马鱼模型系统，我们现在计划对这些新的Ptf 1a-p48靶基因进行功能表征。通过更好地阐明Ptf 1a-p48如何调节祖细胞的生长和分化，这些研究将有助于在胰腺癌和糖尿病的背景下对胰腺祖细胞的最终治疗操作。