Cav3.3-mediated endochondral ossification in a three-dimensional bioprinted GelMA hydrogel

The growth plate (GP) is a crucial tissue involved in skeleton development via endochondral ossification (EO). The bone organoid is a potential research model capable of simulating the physiological function, spatial structure, and intercellular communication of native GPs. However, mimicking the EO process remains a key challenge for bone organoid research. To simulate this orderly mineralization process, we designed an in vitro shCa_v3.3 ATDC5-loaded gelatin methacryloyl (GelMA) hydrogel model and evaluated its bioprintability for future organoid construction. In this paper, we report the first demonstration that the T-type voltage-dependent calcium channel (T-VDCC) subtype Ca_v3.3 is dominantly expressed in chondrocytes and is negatively correlated with the hypertrophic differentiation of chondrocytes during the EO process. Furthermore, Ca_v3.3 knockdown chondrocytes loaded with the GelMA hydrogel successfully captured the EO process and provide a bioink capable of constructing layered and orderly mineralized GP organoids in the future. The results of this study could therefore provide a potential target for regulating the EO process and a novel strategy for simulating it in bone organoids.