EXPRESSION OF THE MEMBRANE-TYPE-3 MATRIX-METALLOPROTEINASE (MT3-MMP) IN HUMAN BRAIN-TISSUES

Membrane-type 3 matrix metalloproteinase (MT3-MMP) is a novel MT-MMP w hich has a transmembrane domain at the C terminus, and mediates activa tion of pro-gelatinase A, just as does MT1-MMP. Previously, we reporte d that MT1-MMP was expressed on microglial cells only in the white mat ter [Yamada T, Yoshiyama Y, Sate H, Seiki M, Shinagawa A, Takahashi M (1995) Acta Neuropathol 90:421-424]. In the present study of both non- neurological and Alzheimer brain tissues, we examined the localization of MT3-MMP by immunohistochemistry. Anti-MT3-MMP antibodies gave posi tive staining of microglial cells in all brain tissues. Positively sta ined microglia were found not only in the white matter but also in the gray matter. Reverse transcriptase-polymerase chain reaction for MT3- MMP mRNA showed the same amount of expression in gray and white matter s, while that for gelatinase A and MT1-MMP mRNA expressed much higher in the white matter than in the gray matter. These results suggest tha t MT3-MMP may play a role on microglial cells, although its role may b e different from MT1-MMP in the brain.