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P2‐216: Proteomic analysis of TgCRND8 mice brain in condition of altered one‐carbon metabolism
Author(s) -
Fuso Andrea,
Cavallaro Rosaria A.,
Borro Marina,
Nicolia Vincenzina,
Gentile Giovanna,
Simmaco Maurizio,
Scarpa Sigfrido
Publication year - 2010
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.2010.05.1265
Subject(s) - biology , difference gel electrophoresis , biochemistry , proteomics , metabolism , chemistry , microbiology and biotechnology , gene
finding in Alzheimer’s disease, in which Ab vascular deposits are featured in >80% of the cases. CAA can compromise cerebral blood flow causing cerebral hemorrage and cognitive impairment. Although the impact of these lesions is broadly recognized, very little is known about the mechanisms causing degeneration of cerebral vascular cells in CAA. Familial Ab variants with substitutions at positions 21-23 are primarily associated with CAA, and they manifest clinically with cerebral hemorrhage or dementia. The recently reported Piedmont L34V Ab mutant, located outside the hot-spot 21-23, shows a similar hemorrhagic phenotype, albeit less aggressive than the widely studied Dutch E22Q variant. Methods: In our studies we challenged human brain microvascular endothelial (EC) and smooth muscle cells (SMC) with both variants and wild-type Ab40, and we studied the apoptotic pathways triggered by these peptides. Results: Structural analyses of the different Ab variants showed that apoptosis preceded fibril formation in all cases, correlating with the presence of oligomers and/or protofibrils. Induction of analogous caspase-mediated mitochondrial pathways was elicited by all peptides, although within different time-frames and intensity. Furthermore, vessel-wall cell death was prevented either through pharmacological inhibition of mitochondrial cytochrome c release or by the action of panand pathway-specific caspase inhibitors, giving clear indication of the independent or synergistic engagement of both extrinsic and intrinsic apoptotic mechanisms. In particular, we found that the activation of caspase 8, usually triggered by death receptors, preceded that of caspase 9. We also confirmed the activation of BID, a downstream effector of caspase-8, known to contribute to the release of Cytochrome C from the mitochondria, causing in turn secondary engagement of caspase-9. Pathway specific PCR arrays demonstrated the involvement of TNF-receptor family members. Conclusions: Overall, our data suggests a primary involvement of death receptors in Ab-induced vascular cell apoptosis. Our studies support the notion that rare genetic mutations constitute unique paradigms to understand the molecular pathogenesis of CAA, and could lead to the identification of new targets for therapeutic intervention.