A zebrafish model to investigate beta-cell functional maturation and heterogeneity

-细胞是胰腺中高度专业化的内分泌细胞的一小部分，它们产生胰岛素，胰岛素是生存所需的激素，也是适当调节能量平衡的关键。虽然越来越多的人认识到存在相当大的细胞异质性，但我们对这种异质性的基础和意义以及指导细胞成熟的因素的了解仍然很少。 斑马鱼为阐明细胞发育和成熟的分子机制提供了一个很好的模型。从遗传和生理角度来看，斑马鱼与人类惊人地相似。事实上，所有参与控制哺乳动物新陈代谢的器官和细胞都存在于这些鱼中。它们也很容易受到基因工程的影响，产生新的鱼类线条，以便对基因、蛋白质和细胞的功能进行复杂的探测。使用斑马鱼作为模式生物的一个特别有用的方面是，它们的发育非常迅速。此外，这些胚胎非常透明，这一特点使它们成为研究脊椎动物发育的理想选择。因此，对于斑马鱼，我们可以实时可视化活着的生物体中细胞发育的整个过程，以及监测细胞的功能成熟。 我们的总体目标是描绘胰岛素分泌细胞成熟的分子途径，并从发育和生理角度研究细胞异质性。这将通过以下三个具体目标来实现： 目的1：研究斑马鱼的细胞功能成熟。我们将使用一种新的斑马鱼转基因品系，它可以在体内可视化细胞刺激-分泌耦合。 目的：确定在成年斑马鱼胰腺发育过程中出现的不同谱系的胰岛细胞是否与胰岛细胞的异质性有关。我们的一个主要假设是，细胞由不同的亚群组成，这些亚群专门分泌胰岛素以响应营养或在组织损伤发生时增殖。为了研究这一方面，我们将使用一种新型的斑马鱼转基因品系，在那里我们可以标记不同的细胞种群，并在鱼类的整个生命过程中跟踪它们，以评估它们特定的遗传特征和功能。 目的：阐明营养感知在细胞功能成熟中的作用。斑马鱼细胞如何感知营养并协调对刺激的反应还没有被研究过。我们将使用基因工具和实时成像方法来探测对正确的营养感知至关重要的关键成分。 总而言之，这种前所未有的细胞表征深度将提供对细胞生物学和控制细胞发育、成熟和功能的分子机制的更深层次的了解。

-cells are a small population of highly specialized endocrine cells in the pancreas that produce insulin, a hormone required for survival and key to the proper regulation of energy homeostasis. While there is an increasing appreciation that there exists considerable -cell heterogeneity, our understanding of the basis and significance of this heterogeneity, along with the factors guiding -cell maturation, remain poorly understood. Zebrafish provide an excellent model to elucidate the molecular mechanisms underlying the development and maturation of -cells. From a genetic and physiological perspective, zebrafish are surprisingly similar to humans. Indeed, all organs and cells involved in controlling mammalian metabolism are present in these fish. They are also readily amenable to genetic engineering to generate novel lines of fish to permit sophisticated probing of the function of genes, proteins and cells. A particularly useful aspect of using zebrafish as a model organism is the fact that they develop very rapidly. Moreover, the embryos are remarkably transparent, a characteristic that makes them ideal to study vertebrate development. Therefore, with zebrafish we can visualize the entire process of -cell development, as well as monitor -cell functional maturation, in real time in a living organism. Our overall goal is to delineate the molecular pathways underlying the maturation of insulin-secreting cells, and to investigate -cell heterogeneity from a developmental and physiological perspective. This will be achieved by the following three specific objectives: Objective 1: To delineate -cell functional maturation in zebrafish. We will use a novel zebrafish transgenic line which allows visualization of -cell stimulus-secretion coupling in vivo. Objective 2: To determine whether the different lineages of -cells arising during pancreas development contribute to -cell heterogeneity in the adult zebrafish pancreas. One of our main hypotheses is that -cells are composed of different sub-populations which are specialized either to secrete insulin in response to nutrients or proliferate when tissue damage occurs. To investigate this aspect, we will use a novel zebrafish transgenic line where we can label different -cell populations and follow them through the entire life of the fish to assess their specific genetic profile and function. Objective 3: To delineate the contribution of nutrient sensing to -cell functional maturation. How zebrafish -cells sense nutrients and coordinate responses to stimuli has not been investigated. We will use genetic tools combined with live imaging approaches to probe the key components essential to proper nutrient sensing. Collectively, this unprecedented depth of -cell characterization will provide a deeper understanding of -cell biology and the molecular mechanisms that control -cell development, maturation and function.