Degenerative diseases are associated with tissue-localized aggregation of proteins in a variety of morphologies, including fibrillar cross-?-sheet assemblies referred to as amyloid fibrils. The most prominent neurodegenerative diseases among the elderly, Alzheimer's disease, and the Lewy body diseases (including Parkinson's disease) appear to result from a loss in the balance between protein synthesis, folding to a native functional state or maintenance of the natively unfolded state, aggregation, and degradation. In Alzheimer's disease, the natively unfolded A? peptide forms fibrillar aggregates that are the principal component of intracellular and extracellular plaques, along with intracellular deposits of hyperphosphorylated tau. Parkinson's disease is characterized by cytoplasmic a-synuclein aggregates associated with degenerating dopaminergic neurons in the substantia nigra and other brain areas. Clinical observations suggest a correlation between oxidative stress/inflammation, aggregation and degenerative diseases. Past studies have demonstrated that hydrophobic aldehydes derived from oxidative stress, in particular 4-hydroxynonenal and the atheronals, exacerbate aggregation through thermodynamic and kinetic perturbations mediated by covalent and non-covalent modifications of A? and a-synuclein, which may help to explain the occurrence of sporadic Alzheimer's and Parkinson's disease. The research proposed herein seeks to understand the effect of hydrophobic aldehydes on the maintenance of protein homeostasis in cells and multicellular organisms and the effect that these covalent modifications have on degenerative disease phenotypes in organismal models of degenerative diseases. Besides evaluating the influence of a new set of common lipid-derived aldehydes on aggregation in the absence and presence of biologically relevant membranes, we will discern their ability to inhibit the biological machinery that maintains organismal protein homeostasis, including the disaggregase activity recently discovered in human cells. We propose new methodology to follow protein aggregation in living human cells and in multicellular organisms using FlAsH fluorophores, to complement a previously developed kinetic aggregation assay in which seeding of aggregation by cell homogenates is the readout. Using these methods, we will assess the influence of the hydrophobic aldehydes on protein aggregation in vivo and discern whether quantification of aggregation in organisms explains toxicity as a function of aldehyde concentration in organisms with low or high levels of aggregation-prone protein expression. Transcriptional analysis of the protein homeostasis network upon aldehyde treatment in the presence of controllable levels of aggregation-prone proteins should provide much insight into the etiology of sporadic neurodegenerative diseases associated with aging, aggregation, and oxidative stress.

Public Health Relevance

Clinical observations suggest a correlation between oxidative stress/inflammation, aggregation and degenerative diseases, such as Alzheimer's disease and Parkinson's disease. This project seeks to understand the influence of protein-modifying hydrophobic aldehydes, derived from the aberrant oxidation of membrane components, on the maintenance of protein homeostasis in cells and multicellular organisms, and the effect that these covalent modifications have on degenerative diseases. We will explore the hypothesis that covalent modifications of aggregation-prone proteins in organisms could exacerbate aggregation and the associated pathology and possibly also modify and inhibit the biological machinery that maintains cellular protein homeostasis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS050636-05
Application #
7735974
Study Section
Biophysics of Neural Systems Study Section (BPNS)
Program Officer
Corriveau, Roderick A
Project Start
2004-12-01
Project End
2014-06-30
Budget Start
2009-07-01
Budget End
2010-06-30
Support Year
5
Fiscal Year
2009
Total Cost
Indirect Cost
Name
Scripps Research Institute
Department
Type
DUNS #
781613492
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Liu, Yu; Tan, Yun Lei; Zhang, Xin et al. (2014) Small molecule probes to quantify the functional fraction of a specific protein in a cell with minimal folding equilibrium shifts. Proc Natl Acad Sci U S A 111:4449-54
Zhang, Xin; Liu, Yu; Genereux, Joseph C et al. (2014) Heat-shock response transcriptional program enables high-yield and high-quality recombinant protein production in Escherichia coli. ACS Chem Biol 9:1945-9
Palhano, Fernando L; Lee, Jiyong; Grimster, Neil P et al. (2013) Toward the molecular mechanism(s) by which EGCG treatment remodels mature amyloid fibrils. J Am Chem Soc 135:7503-10
Talantova, Maria; Sanz-Blasco, Sara; Zhang, Xiaofei et al. (2013) A? induces astrocytic glutamate release, extrasynaptic NMDA receptor activation, and synaptic loss. Proc Natl Acad Sci U S A 110:E2518-27
Lee, Jiyong; Culyba, Elizabeth K; Powers, Evan T et al. (2011) Amyloid-? forms fibrils by nucleated conformational conversion of oligomers. Nat Chem Biol 7:602-9
Usui, Kenji; Hulleman, John D; Paulsson, Johan F et al. (2009) Site-specific modification of Alzheimer's peptides by cholesterol oxidation products enhances aggregation energetics and neurotoxicity. Proc Natl Acad Sci U S A 106:18563-8
Bieschke, Jan; Siegel, Sarah J; Fu, Yanwen et al. (2008) Alzheimer's Abeta peptides containing an isostructural backbone mutation afford distinct aggregate morphologies but analogous cytotoxicity. Evidence for a common low-abundance toxic structure(s)? Biochemistry 47:50-9
Balch, William E; Morimoto, Richard I; Dillin, Andrew et al. (2008) Adapting proteostasis for disease intervention. Science 319:916-9
Powers, Evan T; Powers, David L (2008) Mechanisms of protein fibril formation: nucleated polymerization with competing off-pathway aggregation. Biophys J 94:379-91
Stewart, Cameron R; Wilson, Leanne M; Zhang, Qinghai et al. (2007) Oxidized cholesterol metabolites found in human atherosclerotic lesions promote apolipoprotein C-II amyloid fibril formation. Biochemistry 46:5552-61

Showing the most recent 10 out of 13 publications