Title Abeta - induced BACE - 1 cleaves N - terminal sequence

We would be very pleased if you would consider our manuscript for publication in Biochemical and Biophysical Research Communications. Below is a brief summary of the background and purpose of our study. In this report, we demonstrated that mPGES-2 can be cleaved by BACE-1, which leads to neuroinflammation in the brain. In addition to APP, novel substrates of BACE-1 have been identified. Furthermore, we demonstrated that amyloid beta treatment augmented protein levels of mPGES-2, which synthesizes PGE2. In addition, we revealed that a sequence of amino acids at the N-terminal of mPGES-2 is cleaved by BACE-1, which results in an activated form of mPGES-2. We also observed the translocation of mPGES-2, BACE-1, and COX-2 to the perinuclear space. Multiple lines of evidence, ranging from molecular and cellular to epidemiological data, have highlighted the importance of inflammation in the pathogenesis of Alzheimer's disease (AD). Our results imply that amyloid beta can evoke neuroinflammation by BACE-1-mediated cleavage of mPGES-2, which can aggravate the pathogenesis of AD. Abstract We previously indicated that amyloid beta (Abeta) augments protein levels of beta-site amyloid precursor protein cleaving enzyme-1 (BACE-1) through oxidative stress. In this study, we revealed that BACE-1 is involved in the cleavage of membrane-bound prostaglandin E2 synthase-2 (mPGES-2) in its N-terminal portion, which, in turn, enhanced the generation of prostaglandin E2 (PGE2). PGE2 results in increased Abeta production, initiating a cell-injuring cycle. Using rat primary cortical neurons, a 48 h treatment with Abeta 1-42 (5 M) resulted in the enhanced extracellular PGE2 levels up to about 1 ng/mL, which was attenuated by treatment with a BACE-1 inhibitor (200 nM). A synthetic peptide sequence of 20 amino acids that included the cleavage site of mPGES-2 (HTARWHL RAQDLHERS AAQLSLSS) was cleaved by recombinant BACE-1, confirmed using reverse-phase high-performance liquid chromatography. Cleaved or activated mPGES-2 augments the generation of PGE2. In addition, mPGES-2 was determined to be colocalized with BACE-1 and cyclooxygenase-2 in the perinuclear region in cells after exposure to Abeta. Exposure of neurons to PGE2 led to cell death, and Abeta production was enhanced by PGE2 (1 ng/mL, 48 h). Collectively, these results suggest that Abeta might cause neuroinflammation that aggravates Alzheimer's disease pathogenesis.