We hypothesize that amyloid ?-protein (A?) assembly into neurotoxic oligomers and polymers is a seminal neuropathogenetic process in Alzheimer's disease (AD). If so, assembly inhibition or dissociation of existing assemblies could be effective therapeutic approaches. To test our hypothesis, the structural biology of A? must be elucidated in detail. What conformers form oligomers? By what mechanism? What are the structures of the oligomers thus formed? What is the relative toxicity of each oligomer species? Many, including ourselves, have striven to correlate structure with measures of biological activity. Recent work has suggested that dimeric or trimeric assemblies are important neurotoxins, but hexameric, nonameric, dodecameric, and larger oligomers also have been shown to be potent neurotoxins. The long-term goal of this proposal is to move past simple quaternary structure determination to elucidation of A? monomer secondary and tertiary structure dynamics and the determination of mechanisms of monomer oligomerization. This means eventually understanding the interatomic interactions that control the dynamics, and in doing so, identifying therapeutic targets at atomic resolution. This "knowledge-based" approach is distinct from, but complementary to, high-throughput screening strategies. Both approaches should be executed to maximize the chances for identifying efficacious, disease-modifying therapeutic agents. We propose here to: (1) elucidate the physical biochemistry of A? monomer folding and self-assembly;and (2) establish structure-neurotoxicity relationships of the A? assemblies thus formed. To do so, we will chemically synthesize A? peptides in which specific amino acids and chemical bonds are altered and then study the conformational dynamics and assembly of these peptides. The positions of these alterations, and the alterations themselves, have been chosen carefully so as to reveal the key structural features of the A? molecule that control its assembly into structures that damage or kill neurons. We will identify, isolate, and structurally characterize specific types of assemblies and then determine quantitatively the toxic activity of each assembly by treating primary neurons in culture. The depth of understanding of the structures of the assemblies obtained in the first aim will be unprecedented. Thus the knowledge gained through this "structure-activity correlation" process is expected to provide the most accurate assessment of which assemblies, and which structures (at atomic resolution) on these assemblies, should be targeted therapeutically. In addition to its contributions to an improved understanding of AD and its treatment, results of the proposed project should have relevance for studies of other neurodegenerative diseases linked to aberrant protein assembly. These include Parkinson's, Huntington's, amyotrophic lateral sclerosis, familial amyloid polyneuropathy, and the prionoses.

Public Health Relevance

This project will advance our understanding of how a protein, the amyloid-protein, causes Alzheimers disease. This understanding can be translated directly into the development of a new class of drugs that have the potential to modify or cure the disease. The project also will be of relevance to Parkinsons, Huntingtons, amyotrophic lateral sclerosis, familial amyloid polyneuropathy, the prionoses, and other neurodegenerative diseases of aging.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS038328-13
Application #
8625341
Study Section
Special Emphasis Panel (ZRG1-MDCN-C (02))
Program Officer
Corriveau, Roderick A
Project Start
1998-12-10
Project End
2015-02-28
Budget Start
2014-03-01
Budget End
2015-02-28
Support Year
13
Fiscal Year
2014
Total Cost
$623,961
Indirect Cost
$218,792
Name
University of California Los Angeles
Department
Neurology
Type
Schools of Medicine
DUNS #
092530369
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Roychaudhuri, Robin; Lomakin, Aleksey; Bernstein, Summer et al. (2014) Gly25-Ser26 amyloid ?-protein structural isomorphs produce distinct A?42 conformational dynamics and assembly characteristics. J Mol Biol 426:2422-41
Do, Thanh D; LaPointe, Nichole E; Sangwan, Smriti et al. (2014) Factors that drive peptide assembly from native to amyloid structures: experimental and theoretical analysis of [leu-5]-enkephalin mutants. J Phys Chem B 118:7247-56
Roychaudhuri, Robin; Yang, Mingfeng; Deshpande, Atul et al. (2013) C-terminal turn stability determines assembly differences between Aýý40 and Aýý42. J Mol Biol 425:292-308
Lv, Zhengjian; Roychaudhuri, Robin; Condron, Margaret M et al. (2013) Mechanism of amyloid *-protein dimerization determined using single-molecule AFM force spectroscopy. Sci Rep 3:2880
Mizwicki, Mathew T; Liu, Guanghao; Fiala, Milan et al. (2013) 1*,25-dihydroxyvitamin D3 and resolvin D1 retune the balance between amyloid-* phagocytosis and inflammation in Alzheimer's disease patients. J Alzheimers Dis 34:155-70
Lv, Zhengjian; Condron, Margaret M; Teplow, David B et al. (2013) Nanoprobing of the effect of Cu(2+) cations on misfolding, interaction and aggregation of amyloid ýý peptide. J Neuroimmune Pharmacol 8:262-73
Rosensweig, Clark; Ono, Kenjiro; Murakami, Kazuma et al. (2012) Preparation of stable amyloid ýý-protein oligomers of defined assembly order. Methods Mol Biol 849:23-31
Roychaudhuri, Robin; Yang, Mingfeng; Condron, Margaret M et al. (2012) Structural dynamics of the amyloid ýý-protein monomer folding nucleus. Biochemistry 51:3957-9
Noguchi, Akihiko; Matsumura, Satoko; Dezawa, Mari et al. (2009) Isolation and characterization of patient-derived, toxic, high mass amyloid beta-protein (Abeta) assembly from Alzheimer disease brains. J Biol Chem 284:32895-905
Roychaudhuri, Robin; Yang, Mingfeng; Hoshi, Minako M et al. (2009) Amyloid beta-protein assembly and Alzheimer disease. J Biol Chem 284:4749-53

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