MMP3 and Alzheimer disease: In a transgenic mouse model of AD, expression of MMP-2 and MT1-MMP, a potent MMP-2 activator, was found in reactive astrocytes around amyloid plaques [45], and higher levels of Aβ1–42 increased the production of MMP-3, MMP-12, and MMP-13 in microglia [47].