WHITE-MATTER MICROGLIA PRODUCE MEMBRANE-TYPE MATRIX METALLOPROTEASE, AN ACTIVATOR OF GELATINASE-A, IN HUMAN BRAIN-TISSUES

Membrane-type matrix metalloprotease (MT-MMP) is an activator of gelat inase A (MMP-2), which has previously been found in carcinoma cells. W e examined non-neurological and Alzheimer's disease brain tissues for MT-MMP by immunohistochemistry and in situ hybridization. The anti-MT- MMP antibodies gave positive staining of brain microglial cells in all the brain tissues, Positively stained microglia were found only in th e white matter. The cells producing MT-MMP protein were also shown to be white matter microglia. These results provide further evidence that activated gelatinase A, which may be a processing enzyme for degradat ion of beta-amyloid protein, may be produced in white matter microglia .