This research project aims to elucidate the molecular and cellular mechanism underlying epithelial morphogenesis by analyzing cellular dynamics in ES cell-derived optic cup formation. Using a multi-photon microscope, we have observed cellular dynamics (cell division, cell migration and cell shape) during in vitro optic cup formation. These observations revealed that cells in the hinge region between neural retina and retinal pigmented epithelium had a higher proliferative capacity than the other regions. We have also investigated the spatiotemporal dynamics of intracellular calcium concentration during optic cup morphogenesis in vitro. Calcium is a versatile and universal messenger that is implicated in the regulation of embryonic development and tissue morphogenesis. We found that spontaneous calcium transients were specifically induced in hinge cells during a tissue deformation. A rise of intercellular calcium concentration induces cell shape changes in retinal neuroepithelium. After calcium transients, apical constriction and apico-basal contraction occur in these cells. These results suggest that a spatiotemporally regulation of calcium transients may have a role in optic cup morphogenesis.

In addition, we developed an optimized 3D culture of human ES cells for self-organized cortical tissue formation (Kadoshima et al., PNAS 2014). Self-organized cortical tissue spontaneously forms a polarity along the dorsocaudal-ventrorostral axis, and the neuroepithelium self-forms a multilayered structure including three neuronal zones and three progenitor zones.