Beta-amyloid peptide (Ab), the primary protein component of senile plaques in AIzheimer's disease (AD), plays an important role in neurotoxicity. Peptide structure and aggregation state are important in toxicity. However, the exact structure of the toxic form of the peptide and the mechanism by which it interacts with a cell to cause toxicity are unknown. ? ? Based on our preliminary results, we hypothesize that one or more intermediate sized oligomers of Ab (smaller than a fibril) interact with cells via a membrane interaction that leads to toxicity; that this interaction with the membrane will involve specific residues on the surface of the Ab oligomer (and that those residues involved in the interaction will be the same, regardless of the size of Ab oligomer interacting with the membrane); and that cell toxicity can be prevented by preventing the Ab-membrane interaction, either by altering peptide residues involved in the peptide membrane interaction, or by altering membrane components involved in the interaction. ? ? To test our hypothesis, we will use a variety of methods to fractionate Ab and/or prepare Ab with different degrees of oligomerization/aggregation. We will develop a rapid method for assessment of Ab peptide biological activity (based on Ab-induced GTPase activity) that leads to toxicity. We will use hydrogen exchange followed by mass spectrometry (HX-MS) to characterize the exposed surfaces of oligomers associated with biological activity and to determine which regions of the peptide are buried in the membrane during peptide-membrane interactions. Finally, we will address the biological relevance of the interactions examined by determining if inhibition of those interactions via chemical modification of residue substitution results in attenuated GTPase activity or toxicity. If our hypothesis, in its entirety is correct, insights gained from these investigations will provide the basis for the design of agents that interfere directly with Ab-membrane interactions and prevent toxicity. If, however, only a portion of our hypothesis is correct, we will, at the least, have developed new tools with which to investigate Ab-self and Ab-membrane interactions associated with toxicity. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS042686-04
Application #
7052787
Study Section
Special Emphasis Panel (ZRG1-BECM (01))
Program Officer
Sutherland, Margaret L
Project Start
2003-06-01
Project End
2008-05-31
Budget Start
2006-06-01
Budget End
2008-05-31
Support Year
4
Fiscal Year
2006
Total Cost
$317,201
Indirect Cost
Name
University of Maryland Balt CO Campus
Department
Engineering (All Types)
Type
Schools of Engineering
DUNS #
061364808
City
Baltimore
State
MD
Country
United States
Zip Code
21250
Stephen, Elizabeth A; Venkatasubramaniam, Arundhathi; Good, Theresa A et al. (2014) The effect of glycation on arterial microstructure and mechanical response. J Biomed Mater Res A 102:2565-72
Keshet, Ben; Yang, In Hong; Good, Theresa A (2010) Can size alone explain some of the differences in toxicity between beta-amyloid oligomers and fibrils? Biotechnol Bioeng 106:333-7
Ramos, Irina; Fabris, Dan; Qi, Wei et al. (2009) Kinetic study of beta-amyloid residue accessibility using reductive alkylation and mass spectrometry. Biotechnol Bioeng 104:181-92
Qi, Wei; Zhang, Aming; Good, Theresa A et al. (2009) Two disaccharides and trimethylamine N-oxide affect Abeta aggregation differently, but all attenuate oligomer-induced membrane permeability. Biochemistry 48:8908-19
Zhang, Aming; Qi, Wei; Good, Theresa A et al. (2009) Structural differences between Abeta(1-40) intermediate oligomers and fibrils elucidated by proteolytic fragmentation and hydrogen/deuterium exchange. Biophys J 96:1091-104
Qi, Wei; Zhang, Aming; Patel, Dhara et al. (2008) Simultaneous monitoring of peptide aggregate distributions, structure, and kinetics using amide hydrogen exchange: application to Abeta(1-40) fibrillogenesis. Biotechnol Bioeng 100:1214-27
Patel, Dhara; Good, Theresa (2007) A rapid method to measure beta-amyloid induced neurotoxicity in vitro. J Neurosci Methods 161:1-10
Lee, Sungmun; Fernandez, Erik J; Good, Theresa A (2007) Role of aggregation conditions in structure, stability, and toxicity of intermediates in the Abeta fibril formation pathway. Protein Sci 16:723-32
Wang, Steven S-S; Tobler, Scott A; Good, Theresa A et al. (2003) Hydrogen exchange-mass spectrometry analysis of beta-amyloid peptide structure. Biochemistry 42:9507-14