MMP-3 ELISA Kit, Human

MMP-3 is a 45 kDa protein with a wide range of connective tissue substrates, including proteoglycans, gelatin, laminin, fibronectin and collagen (types III, IV and IX). In addition, MMP-3 can stimulate the other enzymes in the MMPs group, such as MMP-1, MMP-7, MMP-8, MMP-9 and MMP-13. This stimulation increases biochemical substance degradation, including degradation of type II collagen, the most important type of collagen in the extracellular matrix (ECM).² Moreover, MMP-3 can activate several serpin-type serine proteinase inhibitors. In addition, MMP-3 can release a number of cell surface molecules, including E-cadherin, a known contributor to cancer development. Thus, MMP-3 exhibits a number of activities that would make it a particularly good tumor promoter.³ MMP-3 is produced by various types of cells; fibroblast, smooth muscle cells, and macrophages. Similar to other secreted proteinases, the catalytic activity of MMP-3 is regulated at four stages, namely transcription, compartmentalization, proenzyme activation and enzyme inactivation by natural inhibitors. The production of MMP-3 is mainly regulated at the level of transcription. The expression of MMP-3 in unstimulated cells is low, but it is induced by a variety of extracellular stimuli, including mitogenic growth factors, cytokines and contact with the extracellular matrix. Owing to the similarities in structure across the MMP family, it is important to distinctively control transcription according to cell type or different stimulators. Several transcription factors, including NF-kappaB (nuclear factor kappaB), the transcription factor ETS-1 (E26 transformation-specific-1) and AP-1 (activator protein-1), are reported to be involved in the transcriptional induction of MMP-3. MMP-3 is known to mediate the release of macrophage chemotactic activity from chondrocytes. In addition, serum MMP-3 level is a clinically useful maker for predicting joint destruction and for disease activity in rheumatoid arthritis (RA).⁴