Three-dimensional culture technology: Self-organized spheroid culture drives osteocytogenesis

Three-dimensional (3D) culture technology developing organoids exerts a powerful impact to recapitulate the structure and function of certain organs in vitro for the fundamental biology and regenerative medicine. While studies on organoids for osteocyte-related model have not yet been reported, the osteocyte plays a role as a control tower to regulate the bone remodeling by controlling osteoclasts and osteoblasts. In this study, we fabricated 3D self-organized spheroids reconstructed by mouse osteoblast precursor cells (MC3T3-E1) as well as human bone marrow derived mesenchymal stem cells (MSC), and further investigated their osteocyte differentiation capability. As a result of real-time PCR and immunostaining, the spheroid culture greatly up-regulated osteocyte markers in a short period of time, 2 days, compared to the conventional two-dimensional (2D) monolayer model. Consequently, the results altogether suggest that the 3D culture technology using the self-organized spheroids rendered the osteocyte-likeness and further is expected to become a new in vitro model to represent the osteocytes.