Abstract

Osteoarthritis (OA) is an increasingly common degenerative joint condition, estimated to affect more than 100 million people worldwide and more than 40% of people over 70 years of age. There is currently no pharmacological cure. The genetic contribution to osteoarthritis is estimated at between 39 and 60% in knee and hip OA respectively and a number of Genome Wide association studies have identified a number of alleles and loci that confer increased susceptibility to OA. In the last few years a number of key studies have demonstrated that genes known to play a role in the normal skeletal developmental processes of endochondral ossification, chondrocyte hypertrophy and joint formation are reactivated during osteoarthritis progression. Significantly, in some cases modification of these developmental genes can modulate osteoarthritis severity. The high levels of genetic contribution make osteoarthritis an ideal target for both forward genetic screening efforts focused on identifying novel genes involved in chondrocyte differentiation and hypertrophy, which are likely to be involved in osteoarthritis progression and reverse genetics focused on modulation of genes involved in developmental skeletogenesis in later life. The functional study of genes associated with aging can be problematic in part because of the limited availability of animal models and the high costs associated with keeping aged animals. Therefore, the developmental aspect opens up the prospect of using chemical screens, such as those commonly performed in the zebrafish and frogs, to identify potential pharmaceutical modifiers of disease phenotypes. Here, we explore the current models for OA and compare genes, including mechanosensitive genes, involved in developmental joint formation and osteoarthritis.

Authors and Affiliations