Articular Cartilage Maturation and Repair (Postdoctoral Fellowship for Michael Mienaltowski)

Articular cartilage is very important for joint movement and the dissipation ofbiomechanical forces placed on joints during exercise. Yet, cellular and molecular mechanisms that regulate the synthesis and breakdown of cartilage by chondrocytes when adapting to meet the needs of a healthy, fully-functional joint remain poorly understood. The lack of a strong foundation of knowledge about chondrocyte function makes it difficult to answer even basic questions about the mechanisms essential for cartilage maturation and repair. In order to better understand how chondrocytes function during maturation and how attempts are made at the healing of joint surface lesions, we intend to examine differential patterns of gene expression. Chondrocyte gene expression from normal adult cartilage will be compared to three different groups: 1) neonatal articular cartilage, 2) isolated articular chondrocytes allowed to "dedifferentiate" in culture, and 3) repair tissue from articular cartilage lesions. Initial genomic-scale comparisons will be made through micro array transcriptional profiling using an equine-specific cartilage cDNA microarray containing 9,322 unique clone sets derived from the articular cartilage of a thoroughbred yearling. As these comparisons 8!e made, patterns of gene expression will elucidate which clones to further investigate because they contribute significantly to the functional adaptation of chondrocytes during maturation and repair.