Phenotypic redifferentiation of dedifferentiated microtia chondrocytes through a three-dimensional chondrogenic culture system.

Chondrocytes from microtia patients are a valuable cell source for the tissue-engineering of auricles. However, dedifferentiation of microtia chondrocytes remains an obstacle for clinical translation. Strategies, such as three-dimensional (3D) culture systems, and the use of chondrogenic growth factors, have successfully induced redifferentiation of dedifferentiated chondrocytes from healthy individuals. However, it remains unknown whether these strategies are similarly effective for microtia patient-derived chondrocytes, which may carry genomic defects. To address this issue, dedifferentiated microtia chondrocytes (DMCs) were cultured in a 3D chondrogenic culture system for 4-8 weeks to investigate their redifferentiated properties and to generate redifferentiated microtia chondrocytes (RMCs). To predict the degree and course of redifferentiation, RMCs at different time points were harvested and examined for cell morphology, cell proliferation, type II collagen expression at passaging, and chondrogenic capacity. We show that a 3D chondrogenic culture system can effectively induce DMCs to become redifferentiated, functional chondrocytes, enabling them to regenerate mature cartilage. Furthermore, RMCs achieved their full original function after culture in the chondrogenic culture system for 6-8 weeks. Interestingly, redifferentiation of microtia chondrocytes exhibited a time-dependent trend. Although the primary mechanism by which the 3D chondrogenic culture system regulated the transition of DMCs into RMCs remains unknown, the current study provides deeper insight into microtia chondrocytes and promotes clinical translation of tissue-engineered auricles.