Long-term live imaging of the Drosophila adult midgut reveals real-time dynamics of division, differentiation, and loss

Organ renewal is governed by the dynamics of cell division, differentiation, and loss. To study these dynamics in real time, we present a platform for extended live imaging of the adult Drosophila midgut, a premier genetic model for stem cell-based organs. A window cut into a living animal allows the midgut to be imaged while intact and physiologically functioning. This approach prolongs imaging sessions to 12-16 hours and yields movies that document cell and tissue dynamics at vivid spatiotemporal resolution. Applying a pipeline for movie processing and analysis, we uncover new, intriguing cell behaviors: that mitotic stem cells dynamically re-orient, that daughter cells use slow kinetics of Notch activation to reach a fate-specifying threshold, and that enterocytes extrude via ratcheted constriction of a junctional ring. By enabling real-time study of midgut phenomena that were previously inaccessible, our platform opens a new realm for dynamic understanding of adult organ renewal.

器官更新受细胞分裂、分化与消亡的动态过程调控。为实时研究此类动态过程，我们搭建了一套可对成年果蝇（Drosophila）中肠进行长期活体成像的平台——成年果蝇中肠是研究干细胞依赖型器官的顶级遗传模型。通过在活体动物体表开设窗口，可在中肠保持结构完整且生理功能正常的状态下对其开展成像。该方法可将成像时长延长至12至16小时，所得影像序列能够以优异的时空分辨率记录细胞与组织的动态变化。通过一套影像处理与分析流程，我们发现了若干新颖且引人关注的细胞行为：有丝分裂干细胞会发生动态重定向；子细胞通过缓慢的Notch激活动力学过程达到细胞命运决定阈值；肠上皮细胞通过连接环的棘轮式收缩完成挤出。本平台可实现此前难以开展的中肠现象实时研究，为动态解析成年器官更新的内在机制开辟了全新研究领域。