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Background
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Proteins of the matrix metalloproteinase (MMP) family are involved in the breakdown of extracellular matrix in normal physiological processes. HME/MMP-12, also called metalloelastase, is reported only in a few cells, including tissue macrophages and hypertrophic chondrocytes. MMP-12 is critical for invasion and destruction in pathologies such as aneurysm and emphysema. The predicted molecular mass of the HME proenzyme is 54 kDa. HME mRNA and protein were detected in human alveolar macrophages. Similar to murine macrophage metalloelastase, HME readily undergoes NH2- and COOH-terminal processing to a mature 22-kDa form. Both recombinant HME expressed in Escherichia coli and native HME derived from human alveolar macrophage-conditioned media degraded insoluble elastin. HME is a unique human metalloproteinase that possesses elastolytic activity and is expressed in alveolar macrophages, MMP-12 mediates smoke-induced inflammation by releasing TNF-alpha from macrophages, with subsequent endothelial activation, neutrophil influx, and proteolytic matrix breakdown caused by neutrophil-derived proteases (Demets IK et al, Thorax, 61:196-201) Clones: 705D10.11
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