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P1‐046: Gene regulation by gamma‐secretase analyzed by microarray
Author(s) -
Restituito Sophie,
Zavadil Jiri,
Ziff Edward,
Zhang Yutong
Publication year - 2011
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2011.05.326
Subject(s) - ectodomain , nicastrin , biology , notch signaling pathway , microbiology and biotechnology , gene , gamma secretase , adam10 , hes1 , microarray analysis techniques , signal transduction , amyloid precursor protein , gene expression , receptor , metalloproteinase , genetics , matrix metalloproteinase , medicine , disintegrin , disease , pathology , alzheimer's disease
Background: Gamma-secretase, which generates amyloid peptide from APP, also cleaves other type I transmembrane proteins, including synaptic proteins such as N-cadherin. The cleavage pathway involves initial ectodomain shedding by a metalloprotease, followed by intramembrane cleavage by gamma-secretase. The C-terminal fragments generated from the cleavage of several of gamma-secretase substrates can have signaling functions and can regulate transcription (Hass et al., 2009). We have previously shown the existence of activity-dependent cleavage of APP and N-cadherin bymetalloproteases and gamma-secretase at synapses. Moreover, these cleavages modify synaptic transmission and can thus provide a novel formof functional synaptic auto regulation. Methods: We thus assayed if gamma-secretase cleavage couldmodify gene regulation in neurons.We performed a microarray expression profiling analysis using RNA isolated from 14 DIV primary hippocampal neurons in culture treated with the gamma-secretase inhibitors, L685458 for 2h or 4h and compared them to untreated controls. The experiment was carried out in duplicate and the normalized array data were analyzed with the DAVID bioinformatic database and the Gene Set Enrichment Analysis (GSEA) tool. Results: Using the DAVID bioinformatic database, we observed a down regulation of genes involved in Notch receptor signaling, including HES1, as expected. Moreover, we found that apoptosis and Wnt signaling programs were remodeled based on both up regulated and down regulated genes. Interestingly a number of genes coding for potassium channels, adhesionmolecules and synaptic proteinswere down regulated. Analogously, using GSEA, we identified down regulation of genes involved in theNotch receptor signaling, aswell as others involved in cell-cell adhesion, such asE-cadherin, and in synaptic transmission such as theNMDA NR2 receptor. Interestingly we also observed a down regulation of MT5MMP gene, a metalloprotease involved in N-cadherin cleavage in neurons, and of Presenilin1, one of the components of gamma-secretase.Conclusions: In conclusion, we generated a catalogue of candidate pathways involved in synaptic function that may be regulated by gamma-secretase. Reference: [1] Hass MR, Sato C, Kopan R, Zhao G (2009) Presenilin:RIP and beyond. Seminars in Cell & Developmental Biology 20:201-210.