AB plays a central role in AD pathogenesis, although there is still a great need to fully define on which of the multiple AB assemblies underlay the neurotoxic properties and the amyloid-forming ability. While soluble oligomers more than fibrillar structures have been implicated in the mechanism(s) of neuronal toxicity, few in vivo experiments and our own recent data indicate that seeding of AB amyloidogenesis in APP transgenic mice can be accelerated by intracerebral infusion of soluble AD brain extracts but not to the same extent by homologous synthetic peptides in various states of aggregation, suggesting the existence of still undefined amyloidogenic co-factors. Two early-onset neurodegenerative conditions, familial British and Danish dementias (FBD and FDD) show extensive pre-amyloid and amyloid deposits, congophilic angiopathy and neurofibrillary tangle pathology, closely resembling AD. The deposited proteins (ABri in FBD and ADan in FDD), nevertheless, differ from AB in length and in primary structure and yet, all species share great propensity to oligomerize, assemble as ion-channel like structures in lipid bi-layers and form fibrils, all suggestive of common pathogenic pathways. We hypothesize that unrelated peptides could adopt similar altered amyloidogenic configurations that trigger comparable downstream detrimental effects in neuronal cells, being capable of accelerating amyloid deposition in vivo when in conjunction with additional amyloidogenic co-factors. Accordingly, we propose:
Aim 1 : to compare oligomeric and fibrillar ABri, ADan and AB assemblies isolated from brains with FBD / FDD / AD as well as from Tg mouse models and determine the structural requirements for synthetic ABri, ADan and AB to form in vitro similar assemblies to those found in vivo;
Aim 2 : to test the functional effect of the oligomeric and fibrillar ABri and ADan species characterized in aim 1 in comparison with analogous AB structures on their differential neurotoxic potential, assessing the induction of specific cell-death mechanisms (activation of initiator and effector caspases, mitochondrial pathways, Ca2+ dysregulation, etc) in ex vivo and in vitro paradigms, validating the results with tissue fractions enriched in oligomeric assemblies as well as synthetic homologues reconstituted in amyloid-depleted tissue extracts;
Aim 3 : to (a) analyze the exogenous amyloidogenic capability of oligomeric/fibrillar AB, ABri and ADan species in vivo in APP and ADanPP Tg animals using intra-hippocampal injections of brain extracts compared with synthetic homologues with analogous oligomerization in the presence/absence of amyloid-depleted brain extracts and (b) conduct a comparative proteomic analysis of the amyloid-inducing extracts to identify common post-translational modifications and/or additional co-factor(s) responsible for the amyloid-inducing activity.

Public Health Relevance

There is extensive experimental data strongly suggesting that amyloid beta (AB) plays a central role in Alzheimer's disease (AD) although basic questions in the pathogenetic mechanisms remain unclear, particularly the role of oligomers and the existence of amyloidogenic co-factors of the disease. To clarify these issues we propose to study two early-onset non-AB neurodegenerative conditions that closely resemble AD: familial British and Danish dementias. The use of these alternative models of neurodegeneration in close comparison with AD cases will help elucidate whether different amyloids trigger common pathogenic mechanisms and are potentially amenable to similar therapeutics strategies.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
5R01AG030539-05
Application #
8452683
Study Section
Clinical Neuroscience and Neurodegeneration Study Section (CNN)
Program Officer
Petanceska, Suzana
Project Start
2009-04-15
Project End
2014-03-31
Budget Start
2013-05-15
Budget End
2014-03-31
Support Year
5
Fiscal Year
2013
Total Cost
$312,468
Indirect Cost
$128,121
Name
New York University
Department
Pathology
Type
Schools of Medicine
DUNS #
121911077
City
New York
State
NY
Country
United States
Zip Code
10016
Doudevski, Ivo; Rostagno, Agueda; Cowman, Mary et al. (2014) Clusterin and complement activation in exfoliation glaucoma. Invest Ophthalmol Vis Sci 55:2491-9
Todd, Krysti; Fossati, Silvia; Ghiso, Jorge et al. (2014) Mitochondrial dysfunction induced by a post-translationally modified amyloid linked to a familial mutation in an alternative model of neurodegeneration. Biochim Biophys Acta 1842:2457-67
Ghiso, Jorge; Fossati, Silvia; Rostagno, Agueda (2014) Amyloidosis associated with cerebral amyloid angiopathy: cell signaling pathways elicited in cerebral endothelial cells. J Alzheimers Dis 42 Suppl 3:S167-76
Tsachaki, Maria; Fotinopoulou, Angeliki; Slavi, Nefeli et al. (2013) BRI2 interacts with BACE1 and regulates its cellular levels by promoting its degradation and reducing its mRNA levels. Curr Alzheimer Res 10:532-41
Ghiso, Jorge A; Doudevski, Ivo; Ritch, Robert et al. (2013) Alzheimer's disease and glaucoma: mechanistic similarities and differences. J Glaucoma 22 Suppl 5:S36-8
Saul, Anika; Lashley, Tammaryn; Revesz, Tamas et al. (2013) Abundant pyroglutamate-modified ABri and ADan peptides in extracellular and vascular amyloid deposits in familial British and Danish dementias. Neurobiol Aging 34:1416-25
Fossati, Silvia; Ghiso, Jorge; Rostagno, Agueda (2012) Insights into caspase-mediated apoptotic pathways induced by amyloid-? in cerebral microvascular endothelial cells. Neurodegener Dis 10:324-8
Calero, Miguel; Rostagno, Agueda; Ghiso, Jorge (2012) Search for amyloid-binding proteins by affinity chromatography. Methods Mol Biol 849:213-23
Tsachaki, Maria; Serlidaki, Despina; Fetani, Andriana et al. (2011) Glycosylation of BRI2 on asparagine 170 is involved in its trafficking to the cell surface but not in its processing by furin or ADAM10. Glycobiology 21:1382-8
Tomidokoro, Yasushi; Tamaoka, Akira; Holton, Janice L et al. (2010) PYROGLUTAMATE FORMATION AT THE N-TERMINI OF ABRI MOLECULES IN FAMILIAL BRITISH DEMENTIA IS NOT RESTRICTED TO THE CENTRAL NERVOUS SYSTEM. Hirosaki Igaku 61:S262-S269

Showing the most recent 10 out of 18 publications