Proteinases and Matrix Degradation

Extra-cellular matrix (ECM) plays critical roles in the normal development and function of the organism by interacting with cells and supporting tissue and organ architectures. The cell-ECM interaction regulates various fundamental cellular functions including growth, differentiation, apoptosis, and migration. The turnover and remodeling of ECM are transient and under strict control in physiologic conditions, and excessive degradation of ECM components by proteinases causes tissue destruction in many pathologic conditions. Thus regulatory mechanisms of ECM degradation are important to understand to reveal pathogenesis of these diseases. In rheumatoid arthritis and osteoarthritis, activity of ECM-degrading proteinases is elevated, causing destruction of joint tissue including cartilage and bone. It is getting clearer that these unbalanced ECM metabolisms are not only due to upregulation of proteinase genes but also other factors. This chapter provides up-to-date information about ECM-degrading proteinases and their regulations in rheumatoid arthritis and osteoarthritis.