GSE202640
Mechanical forces direct the cell fate of inner ear organoids in a stage-dependent manner
During the development, mechanical force plays an important role in shaping the inner ear and establishing regular cellular patterns, however, the effects of ubiquitous mechanical cues on cellular fate determination are not clear. Here we developed stiffness adjustable hydrogels for three-dimensional (3D) cochlear organoid culture, which could precisely simulate the mechanical force from the extracellular matrix (ECM) during the expansion of cochlear progenitor cells (CPCs) and organoid formation. Within a certain range, suitable stiffness can stimulate CPC proliferation through a mechanism requiring integrin/cytoskeleton/YAP signaling. Surprisingly, increasing stiffness could inhibit the proliferation of CPCs and induce the differentiation of organoids, which was mediated by the increased intracellular Ca2+ signaling in CPCs, and further activated Klf2 to promote the differentiation of HCs with bundles. Furthermore, this chemical-defined hydrogel is also suitable for 3D bioprinting, and we printed the spiral-like structure with CPCs and HCs, which provided a promising way for cochlear organoids to further improve our understanding of the organization of the inner ear and contribute to developing new therapeutic approaches for HCs regeneration. Overall design: We establish a chemically defined GelMA-HA-RGD hybrid hydrogel-based 3D culture system for cochlear organoid formation from cochlear progenitor cells. We compared the cells cultured in gels with different degrees of stiffness. Highly resembling the dynamic force pattern from the extracellular matrix in the developmental microenvironment in which inner ear progenitors reside in vivo, the tunable mechanical force in the hybrid hydrogel system manipulated CPC proliferation and differentiation.