Osteoarthritis leads to more contractile and protrusive chondrocytes when cultured in 3D degradable hydrogels

Osteoarthritis (OA) significantly influences chondrocyte behavior, yet its impact on active cell-generated forces, a key indicator of cell-matrix interaction, remains poorly understood. In this study, we used traction force microscopy (TFM) and immunostaining to explore how culture dimensionality (2D versus 3D) affects cell phenotype and contractile dynamics in human articular chondrocytes from both OA and non-OA patients. Our findings reveal that OA alters key proteins involved in force exertion and transmission across both culture dimensionalities, with pronounced phenotypical differences observed in the 3D environment. While OA does not affect chondrocyte-generated tractions in 2D cultures, it enhances contractility in 3D degradable hydrogels, correlating with increased protrusive activity, higher actomyosin engagement, and altered extracellular matrix remodeling. These findings show that the 3D environment highlights OA-related changes in chondrocyte mechanobiology, emphasizing the necessity of considering culture dimensionality and degradability in OA research.