One major limitation hindering the scientific community's ability to develop treatments to reverse osteoarthritis (OA) is that chondrocytes de-differentiate after approximately 10 days in culture under standard monolayer conditions. Micropatterned discs of printed proteins have shown some utility for preventing de-differentiation but they do so by un-naturally restricting cell adhesion. Although chondrocyte phenotype can generally be maintained for much longer in 3D cultures, these methods severely limit analytical techniques for assessing cellular behavior due to optical and diffusion-based limitations. To combine the best of both worlds, we are developing the CellWell - a novel micropatterned platform to prevent chondrocyte de-differentiation in a fully adherent culture while maintaining compatibility with traditional cell culture and analytical techniques. These abilities will make the CellWell a potentially powerful tool to efficiently study the pathogenesis of osteoarthritis at the cellular level.
Articular chondrocytes are very mechanically sensitive cells, responding differently to forces at different magnitudes as well as to forces of the same magnitude applied at different frequencies in ways that either prevent or lead to osteoarthritis (OA). Despite this and the known importance of their cytoskeletal integrity, which distributes forces throughout the cells, surprisingly little is known about how chondrocytes respond to forces exerted upon them by their environment or about what governs their differential response to forces at different frequencies. We are working to determine how the motion and shape of the actin cytoskeleton influences the frequencies and magnitudes of intracellular force transmission through various integrins to regulate the homeostatic expression of anabolic and catabolic factors via Yes-associated protein (YAP) in articular chondrocytes.