Proamyloidogenic effects of membrane type 1 matrix metalloproteinase involve MMP-2 and BACE-1 activities, and the modulation of APP trafficking.

We previously demonstrated that membrane type 1 (MT1) matrix metalloproteinase (MMP) was up-regulated in the hippocampus of the model of transgenic mice bearing 5 familial mutations on human amyloid precursor protein (APP) and presenilin 1 of Alzheimer disease (AD), and that the proteinase increased the levels of amyloid β peptide (Aβ) and its APP C-terminal fragment of 99 aa in a heterologous cell system. Here we provide further evidence that MT1-MMP interacts with APP and promotes amyloidogenesis in a proteolytic-dependent manner in Swedish APP-expressing human embryonic kidney 293 (HEKswe) cells. MT1-MMP-mediated processing of APP releases a soluble APP fragment, sAPP95.