Current imaging approaches limit the ability to perform multiscale characterization of 3D organotypic cultures (organoids) in large numbers. Here, we present an automated multiscale 3D imaging platform synergizing high-density organoid cultures with 3D live single objective light-sheet imaging. It is composed of disposable microfabricated organoid culture chips embedding optical components and a custom laser beam steering unit coupled to a commercial inverted microscope. It streamlines organoid culture and high content 3D imaging on a single user-friendly instrument with minimal manipulations and unprecedented throughput of 300 organoids per hour in 3D. Collecting large number of 3D stacks allowed training deep learning-based algorithms to quantify the organoids morphogenetic organizations at multi-scales, ranging from the sub-cellular scale to the whole organoid level.We validated the versatility and robustness of our approach on intestine, hepatic, neuroectoderm organoids and oncospheres.

Actin cytoskeleton self-organization in two cell types, fibroblasts and epitheliocytes, was studied in cells confined to isotropic adhesive islands. In fibroblasts plated onto islands of optimal size, an initially circular actin pattern evolves into a radial pattern of actin bundles that undergo asymmetric chiral swirling before finally producing parallel linear stress fibers. Epitheliocytes, however, did not exhibit succession through all the actin patterns described above. Upon confinement, the actin cytoskeleton in non-keratinocyte epitheliocytes was arrested at the circular stage, while in keratinocytes it progressed as far as the radial pattern but still could not break symmetry. Epithelial–mesenchymal transition pushed actin cytoskeleton development from circular towards radial patterns but remained insufficient to cause chirality. Knockout of cytokeratins also did not promote actin chirality development in keratinocytes. Left–right asymmetric cytoskeleton swirling could, however, be induced in keratinocytes by treatment with small doses of the G-actin sequestering drug, latrunculin A in a transcription-independent manner. Both the nucleus and the cytokeratin network followed the induced chiral swirling. Development of chirality in keratinocytes was controlled by DIAPH1 (mDia1) and VASP, proteins involved in regulation of actin polymerization..

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