The Loeser lab uses a combination of in vitro studies in articular chondrocytes and in vivo studies in mice to examine molecular mechanisms of joint tissue destruction in aging and osteoarthritis. A major focus of this work is examining how reactive oxygen species regulate cell signaling through oxidation of Cys residues in specific kinases and phosphatases. Pathways of interest include integrin mediated signaling that stimulates matrix metalloproteinase (MMP) expression and IGF-I signaling that stimulates matrix production. Oxidative stress disrupts the balance in the activity of these pathways to favor matrix destruction over repair contributing to the development of osteoarthritis.