Investigating β-cell Functional Heterogeneity in Zebrafish Using Single-Cell Optogenetics

使用单细胞光遗传学研究斑马鱼β细胞功能异质性

• 批准号: 282312683
• 负责人: Professor Dr. Nikolay Ninov, Ph.D.
• 金额: --
• 依托单位: Zentrum für Regenerative Therapien Dresden - CRTD
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/282312683?language=en
• 关键词: Investigating; cell; Functional; Heterogeneity; Zebrafish

There is emerging evidence that the pancreatic beta-cells are heterogeneous and form subpopulations with distinct characteristics. It is believed that individual beta-cells specialize towards performing specific tasks in the islet (e.g. proliferation versus function), which might increase the overall fitness of the cellular community. However, the origins and the role of cell heterogeneity in islet physiology and pathophysiology are yet to be defined. Recently, we identified a critical subpopulation of β-cells, called leader cells, which guide the response of the rest of cells to glucose. When we destroyed precisely the leader cells using photo-ablation, the coordinated islet activity was immediately impaired. In a close collaboration with Prof. Guy Rutter (Imperial College London), we applied high-speed in vivo 3D Ca2+ imaging and novel analytical approaches to reveal that the leader β-cells are the first cells to respond to glucose in both zebrafish and mouse islets. Critically, islet coordination was aberrant in human islets taken from subjects with T2DM. This led us to put forward the concept that leader cells are selectively affected during diabetes progression, leading to islet dysfunction. Thus, the current working model is that the loss of a critical subpopulation of β-cells may impair the function of islets trough disrupted Ca2+ responses. To understand the role of this functional heterogeneity for insulin secretion, during the previous funding period, my group has developed unique state-of-the-art tools to study and manipulate β-cell function. Among our newest tools are transgenic lines with β-cell-specific expression of optogenetic effectors, as well as methods to photo-label and track over time single cells in the islet. Using our new technologies, we propose to address fundamental questions related to the development of leader cells within islets, their stability and metabolic signatures, as well as to define novel molecular markers of leader and follower cells. Moreover, we will apply the new tools to study how leader cells are affected by β-cell stress, either metabolic or inflammatory, and to find out if leader-cells can die or lose their function under such conditions. Addressing these fundamental questions will be paramount to understand why type 2 diabetic islets show normal β-cell mass but impaired cell-coordination and islet function. A possible explanation is that the loss of leader cells prevents the proper functioning of the islets. If this turns out to be the case, new strategies aiming to protecting and restoring leader cells will be necessary.

有新的证据表明，胰腺β细胞是异质的，并形成具有不同特征的亚群。 据信，单个β细胞专门用于在胰岛中执行特定任务（例如增殖与功能），这可能会增加细胞群落的整体适应性。 然而，胰岛生理和病理生理学中细胞异质性的起源和作用还有待确定。 最近，我们发现了一个关键的β细胞亚群，称为领导细胞，它指导其余细胞对葡萄糖的反应。 当我们使用光消融精确地破坏领导细胞时，协调的胰岛活性立即受损。 在与Guy Rutter教授（帝国理工学院伦敦）的密切合作中，我们应用了高速体内3D Ca2+成像和新的分析方法，揭示了领导β细胞是斑马鱼和小鼠胰岛中第一个对葡萄糖做出反应的细胞。 重要的是，在取自T2DM受试者的人胰岛中，胰岛协调异常。 这使我们提出了这样一个概念，即在糖尿病进展过程中，前导细胞受到选择性影响，导致胰岛功能障碍。 因此，目前的工作模型是，β细胞的关键亚群的损失可能通过破坏的Ca2+反应损害胰岛的功能。 为了了解这种功能异质性对胰岛素分泌的作用，在上一个资助期间，我的团队开发了独特的最先进的工具来研究和操纵β细胞功能。 我们的最新工具包括具有β细胞特异性表达的光遗传效应子的转基因系，以及随时间推移对胰岛中的单细胞进行光标记和跟踪的方法。 使用我们的新技术，我们建议解决与胰岛内领导细胞的发展，其稳定性和代谢特征相关的基本问题，以及定义领导细胞和跟随细胞的新分子标记。 此外，我们将应用新的工具来研究领导细胞如何受到β细胞应激的影响，无论是代谢还是炎症，并找出领导细胞在这种条件下是否会死亡或失去功能。 解决这些基本问题对于理解为什么2型糖尿病胰岛显示正常的β细胞质量但受损的细胞协调和胰岛功能至关重要。 一个可能的解释是，前导细胞的丢失阻止了胰岛的正常功能。 如果事实证明是这样的话，就需要采取新的策略来保护和恢复领导细胞。