Characterizing the Role of Pancreatic Progenitors in Regeneration

描述(由申请人提供)：描述胰腺前体细胞在再生中的作用。我们的目标集中在确定在发育或再生过程中用于产生新的β细胞的途径。人们希望这种方法将确定可用于糖尿病治疗的靶点。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。斑马鱼在器官受损后具有非凡的再生组织的能力，我们已经证明这种能力延伸到胰腺中产生胰岛素的β细胞。我们的理由是，在一个容易再生的有机体中，研究组织恢复的机制将更容易和更快。从在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最有效的方法是利用不同的胰腺损伤实验模型。为此，我们的实验室已经开发出：i)一种有效的转基因方法，可以在同时对剩余的胰岛进行成像的同时，特异地去除β细胞；ii)化学诱导的胰腺炎破坏腺泡组织；iii)一种外科手术，切除大部分胰腺(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血统追踪的工具和方法。利用这项技术，我们在幼鱼中鉴定了产生内分泌细胞和中央腺泡细胞的胰腺前体细胞。有了这项技术和获得的经验，我们现在可以绘制不同类型的胰腺细胞的命运图，并确定它们在任何损伤模型的组织损伤后兼性再生中的作用。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，我们证明了Notch信号在发育过程中调节β细胞形成的重要性，最近我们证明了Notch信号在成人胰腺损伤后显著上调。为了找到更多的途径，我们对诱导幼鱼早熟胰岛形成的药物进行了化学筛选。这项工作导致了几部小说的鉴定 参与β细胞分化的途径。有了药物和新开发的遗传方法，我们可以操纵所有这些途径，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年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.