Characterizing the Role of Pancreatic Progenitors in Regeneration

描述（由申请人提供）：表征胰腺祖细胞在再生中的作用。我们的目标是确定用于在发育或再生过程中产生新β细胞的途径。希望这种方法将确定可以用于治疗糖尿病的目标。由于控制脊椎动物胰腺发育和功能的分子机制高度保守，我们已经转向斑马鱼作为研究β细胞生物学和再生的替代模型系统。斑马鱼具有在器官损伤后再生组织的显著能力，并且我们已经表明这种能力延伸到胰腺的胰岛素产生β细胞。我们的理由是，在一个容易再生的生物体中研究组织恢复的机制将更容易和更快。从其他系统中所做的工作来看，很明显，不同的组织损伤方法可以促进不同的再生反应。了解参与再生的细胞和信号的最有效方法是利用不同的胰腺损伤实验模型。为此，我们的实验室开发了：i）一种有效的转基因方法，可以特异性地消融β细胞，同时能够同时对剩余的胰岛进行成像; ii）化学诱导的胰腺炎破坏腺泡组织; iii）切除大部分胰腺的外科手术（部分胰腺切除术）。为了确定参与再生的细胞，我们开发了在斑马鱼中进行远程谱系追踪的工具和方法。用这种技术，我们确定了胰腺祖细胞的幼虫，引起内分泌和中央腺泡细胞的成鱼。有了这项技术和获得的经验，我们现在可以对不同的胰腺细胞类型进行命运映射，并确定它们在任何损伤模型的组织损伤后的兼性再生中的作用。再生的许多方面概括了发育过程中使用的分子途径和机制。例如，我们发现Notch信号在发育过程中调节β细胞形成方面很重要，我们最近证明Notch信号在成人胰腺损伤后显著上调。为了找到更多的途径，我们进行了一项化学筛选，寻找诱导幼鱼早熟胰岛形成的药物。这项工作导致了几个新的识别 参与β细胞分化的途径。随着药物和新开发的遗传方法的掌握，我们可以操纵所有提到的这些途径，并研究它们对胰腺发育和再生的影响。这项工作的目的是确定这些途径是否可以被操纵来诱导成体β细胞新生，并为未来在哺乳动物模型中的研究提供平台。

DESCRIPTION (provided by applicant): Characterizing the role of pancreatic progenitors in regeneration. Our goals are focused on identifying pathways used to generate new beta-cells either during development or regeneration. It is hoped that this approach will identify targets tha can be exploited in the treatment of diabetes. As there is a high degree of conservation in the molecular mechanisms that control vertebrate pancreas development and function, we have turned to the zebrafish as an alternative model system to study beta-cell biology and regeneration. The zebrafish has a remarkable capacity for regenerating tissues following organ damage and we have shown that this ability extends to the insulin producing beta-cells of the pancreas. We reason that it will be easier and faster to study mechanisms involved in tissue recovery in an organism that can readily regenerate. From work done in other systems, it is apparent that different methods of tissue injury can promote different regenerative responses. The most efficient way to learn about the cells and signals involved in regeneration will be to utilize different experimental models of pancreas injury. To these ends our lab has developed: i) An efficient transgenic method to specifically ablate the beta-cells while being able to simultaneously image the remaining islets; ii) Chemically induced pancreatitis destroying the acinar tissue; iii) A surgical procedure to remove a large portion of the pancreas (partial pancreatectomy). In order to ascertain the cells involved in regeneration, we developed the tools and methods to perform long-range lineage tracing in the zebrafish. With this technique, we identified the pancreatic progenitors in the larvae that give rise to endocrine and centroacinar cells of the adult fish. With this technology in hand and the experience gained, we can now fate map different pancreatic cell types and ascertain their role in facultative regeneration following tissue damage from any of our injury models. Many aspects of regeneration recapitulate molecular pathways and mechanisms used during development. For instance, we showed that Notch-signaling was important in regulating beta-cell formation during development and we recently demonstrated that Notch-signaling is dramatically up-regulated following adult pancreas injury. To find more pathways, we carried out a chemical screen for drugs that induce the formation of precocious islets in larval fish. This work led to the identification of several novel pathways involved in beta-cell differentiation. With pharmaceutical and newly developed genetic methods in hand, we can manipulate all these pathways mentioned and study their effects on both pancreas development and regeneration. This work is aimed at ascertaining if these pathways can be manipulated to induce adult beta-cell neogenesis, and provide the platform for future studies in mammalian models.