Optical microscopic imaging, manipulation, and analysis methods for morphogenesis research.

Morphogenesis is a developmental process that shapes multicellular organisms through complex and cooperative cellular movements. To understand the complex interplay between genetic programs and resulting multicellular morphogenesis, it is essential to characterize the morphologies and dynamics at the single-cell level, with an understanding of how physical forces serve as both signaling components and driving forces of tissue deformations. In recent years, advances in microscopy techniques have led to improvements in imaging speed, resolution, and depth. Concurrently, the development of various software packages has supported large-scale, single-cell-level analyses of challenging images. Although these tools have accelerated comprehensive examination of single-cell-level dynamics and mechanical processes during morphogenesis, sophisticated integration requires further expertise. With this background, this review provides a practical overview of those techniques. First, we introduce microscopic techniques for multicellular imaging and image analysis software tools, with a focus on cell segmentation and tracking. Second, we provide an overview of cutting-edge techniques for mechanical manipulation of cells and tissues. Finally, we introduce recent findings on morphogenetic mechanisms and mechanosensations that were achieved by effectively combining microscopy, image analysis tools, and mechanical manipulation techniques. Mini-abstract In this review, we introduce multicellular imaging and image analysis tools. We also provide an overview of state-of-the-art techniques for mechanical manipulations of cells and tissues and give examples of how the combination of these tools and techniques has contributed to elucidating the mechanobiological aspect underlying morphogenesis.