Next-Generation Breast Organoids Capture Human Organogenesis with High-Resolution Live Imaging.

Organoids have emerged as a powerful tool for modeling tissue growth and diseases. In this study, we introduce a groundbreaking organotypic culture technique that replicates the morphology, scale, and heterogeneity of human breast tissue, and includes a mesenchymal-like stromal component. A standout feature of this approach is the use of long-term live imaging at high temporal resolution to directly observe stem cell dynamics during organogenesis, from single cells to mature organ tissue. The system is adaptable for high throughput applications and allows for genetic manipulation of the cells. Real-time imaging of ex-vivo tissue formation reveals a non-canonical process of ductal-lobular morphogenesis and branching, and de-novo generation of a supportive stroma. Incorporating patient-derived single cells from multiple donors offers an enhanced representation of the spectrum of individual responses and the impacts of distinct exposures. While developed for breast tissue, the principles of this technology can serve as a model for the development of similar systems in other tissues, where organoids do not merely reproduce the tissue, but where their regeneration can also be observed and studied. In addition, this model provides a quantitative experimental system to study mechanisms of embryogenesis, development, and tissue organization where biomechanics plays an important role.