Characterization of endogenous and exogenous gamma-secretase activating protein (GSAP) expression in cells

that BIN1 is a genuine genetic determinant of AD. The Amphiphysins (Amph 1 and 2) are expressed in the brain and are involved in endocytosis processes. However, little is known about their potential implications in the pathological process. We aimed at characterizing how BIN1 may act in the AD process. Methods: mRNA levels of Amph 1 and BIN1 were measured in the frontal area of 64 AD brains and 64 controls using the Quantigene technology. The SKNSH-SY5Yand HEK cell lines, stably over-expressing APP695wt were transitorily transfected with a vector expressing BIN1. After 48 hours, supernatants were recovered and cells were lysed. Holo-APP and s-actin were measured by protein blotting. As1-40, As1-42, sAPPa and sAPPs were measured by sandwich ELISA. Finally, we assessed BIN1/Amph 1modulation of Tau and As -mediated neurotoxicity in D. melanogaster. using rough-eye and bristle phenotypes.Results:We observed an increase in expression of both Amph 1 and BIN1 genes in the brains of AD cases compared to controls. BIN1 over-expression in the two cell lines did not modify the APP metabolism whereas BIN1/Amph 1 knockdown suppressed Tau neurotoxicity in D. melanogaster. Conclusions: Our preliminary results indicated that BIN1 is over-expressed in AD brain and might play a role in AD process not by modulating APP metabolism but by controlling Tau proteinopathy-mediated neurotoxicity.