Regulation of exocrine pancreas formation

描述(申请人提供)：胰腺是一种复合腺，由内分泌、外分泌和导管上皮组成，在调节代谢功能和消化活动中发挥核心作用。与这些胰腺间隔相关的功能障碍分别会导致糖尿病、胰腺炎和胰腺癌。尽管它们的功能不同，但所有的胰腺细胞类型都来自于来自前肠内胚层的共同祖细胞群体。近年来，我们在理解启动腹侧和背侧胰腺原基形成和分化的环境信号方面取得了重大进展。此外，Pdx1和Ptf1a已被确定为两个关键的调控因子，它们共同决定了这些原基中胰腺多能前体细胞的命运。最近，FOXA1和Foxa2被证明对胰腺原基的生长和分化以及Pdx1的调节是必不可少的。除了这些因素，对前肠内胚层启动胰腺程序的分子调控知之甚少。此外，尽管已鉴定了大量对胰岛规范、分化和发育至关重要的转录因子，但对外分泌胰腺的规范和发育知之甚少。在这项研究中，我们将探讨GATA因子家族的两个成员GATA4和GATA6在调节胰腺原基规格以及在胰腺外分泌发育和分化中的作用。我们使用GATA4和GATA6的条件敲除等位基因的初步数据表明，它们在这些调控过程中具有部分多余的功能。此外，我们认为GATA蛋白可能与FoxA蛋白协同调控Pdx1，Gata4可能与Ptf1a协同调控外分泌特异基因转录。我们打算在以下特定目的中探讨GATA4和GATA6在早期胰腺形成和外分泌分化中各自的作用：在特定目的1中，我们将通过条件基因切割Sox9+和Pdx1+胰腺原基中的GATA基因，结合遗传谱系追踪来表征GATA对胰腺原基形成的调控。在特定的目标2中，我们将研究GATA因子在外分泌细胞发育中的各自作用。在具体目标3中，我们将通过研究Gata4与Ptf1a或Gata4与Foxa2之间的遗传和物理相互作用，并确定它们各自在调节胰腺基因表达和发育方面的协同活性，来研究Gata4在胰腺特异基因表达中的分子作用。我们还将使用全球CHIP-SEQ和RNA-SEQ分析来确定胰腺中受GATA4和/或GATA6调控的基因集。 与公共卫生相关：胰腺是一个复合腺，由内分泌、外分泌和导管上皮区组成，在新陈代谢功能和消化活动的调节中发挥核心作用。与这些胰腺间隔相关的功能障碍分别会导致糖尿病、胰腺炎和胰腺癌。本文建议的研究将确定和表征有助于胰腺，特别是外分泌胰腺的形成和功能的主要调控途径，以改进胰腺疾病的治疗和组织替代疗法。

DESCRIPTION (provided by applicant): The pancreas is a compound gland comprised of endocrine, exocrine and ductal epithelial compartments that play central roles in the regulation of metabolic functions and digestive activities. Dysfunctions associated with these compartments of the pancreas lead to diabetes, pancreatitis and pancreatic cancer, respectively. Despite their diverse functions, all of the pancreatic cell-types arise from a common progenitor population derived from the foregut endoderm. In recent years, significant advances have been made in our understanding of the environmental signals that initiate the formation and differentiation of the ventral and dorsal pancreatic primordia. Furthermore, Pdx1 and Ptf1a have been identified as two key regulatory factors that cooperate to determine the fate specification of the pancreatic multipotent progenitor cells within these primordia. More recently, Foxa1 and Foxa2 have been shown to be essential for the outgrowth and differentiation of the pancreatic primoridia and the regulation of Pdx1. Beyond these factors, little is known about the molecular regulation of the initiation of the pancreatic program from the foregut endoderm. In addition, although a large number of transcription factors that are essential for pancreatic islet specification, differentiation and development have been characterized, little is known about the specification and development of the exocrine pancreas. In the studies proposed here, we will investigate the roles of two Gata factor family members, Gata4 and Gata6, in the regulation of pancreatic primordia specification and in the development and differentiation of the exocrine pancreas. Our preliminary data using conditional knockout alleles of Gata4 and Gata6 suggest they have partially redundant functions in these regulatory processes. Furthermore, we propose that the Gata proteins may cooperate with the FoxA proteins in the regulation of Pdx1, and Gata4 may cooperate with Ptf1a in the regulation of exocrine- specific gene transcription. We intend to explore the respective roles of Gata4 and Gata6 in early pancreas formation and exocrine differentiation in the following specific aims: In Specific aim 1 we will characterize Gata-mediated regulation of pancreatic primordia formation using conditional gene ablation of the Gata genes in the Sox9+ and Pdx1+ pancreatic primordia, combined with genetic lineage tracing. In Specific aim 2 we will investigate the respective roles of the Gata factors in exocrine cell development. In Specific aim 3 we will investigate the molecular role of Gata4 in pancreas- specific gene expression by exploring genetic and physical interactions between Gata4 and Ptf1a or Gata4 and Foxa2 and determining their respective cooperative activities in regulating pancreas gene expression and development. We will also use global ChIP-Seq and RNA-Seq analysis to identify the set of genes regulated by Gata4 and/or Gata6 in the pancreas. PUBLIC HEALTH RELEVANCE: The pancreas is a compound gland comprised of endocrine, exocrine and ductal epithelial compartments that play central roles in the regulation of metabolic functions and digestive activities. Dysfunctions associated with these compartments of the pancreas lead to diabetes, pancreatitis and pancreatic cancer, respectively. The studies proposed here will identify and characterize the primary regulatory pathways that contribute to the formation and function of the pancreas, especially the exocrine pancreas, to improve treatment and tissue replacement therapies of pancreatic diseases.