MMP-3 - Matrix metalloproteinase-3 (MMP-3), also known as Stromelysin-1, is a matrix metalloproteinase enzyme involved in the breakdown of extracellular matrix proteins and tissue remodeling. The MMP-3 enzyme degrades collagen types II, III, IV, IX, and X, proteoglycans, fibronectin, laminin, and elastin, and can activate other MMPs such as MMP-1, MMP-7, and MMP-9. MMP-3 has been implicated in exacerbating the effects of traumatic brain injury (TBI) through its disruption of the blood-brain barrier, and is also thought to be involved in wound repair, progression of atherosclerosis, and tumor initiation.
MMP-9 - Matrix metalloproteinase 9 (MMP-9) is a 92 kDa secreted protein, belonging to the metzincin (multi domain zinc (II) dependent endopeptidases) superfamily of proteases. It is produced by normal and transformed cells. MMP-9 functions through enzymatic degradation by cleaving extracellular matrix proteins and adhesion molecules (like ICAM-5). These events play major roles in the processes of synaptic plasticity, learning, memory, and morphological reconstruction of targets such as neuronal dendritic spines. MMP-9 has been shown to be linked to various disease states including cancer, cardiovascular disease and arthritis. Specifically, cancer models have shown directly that metastasis/angiogenesis and overall tumor aggression are linked to elevated MMP-9 levels. Cardiovascular issues including myocardial infarction, aneurysms, and atherosclerotic plaques have been shown to be linked to increased MMP-9 levels using knockout and overexpression studies in mice. Allograft studies of renal transplant patients have unearthed links between MMP-9 and immune-mediated tissue rejection (destruction) of the allograft opening up windows for rejection prediction in future transplant cases.