Louisiana Tech University, Department of Biomedical Engineering
Understanding the Molecular Mechanism of Alzheimer's Disease - Quantitative Proteomics of Oxidatively Modified Proteins using iTRAQ Analysis and a Novel Proteomic Reactor
Mark DeCoster, Ph.D., Louisiana Tech University, Department of Biomedical Engineering
Steve Soper, Ph.D., Louisiana State University, Department of Chemistry
Kermit Murray, Ph.D., Louisiana State University, Department of Chemistry
Project R3 (May 1, 2010 - April 30, 2012)
Pilot Project (May 1, 2009 – April 30, 2010)
Alzheimer's Disease (AD), the most common form of dementia in the elderly, may manifest as neuropathological changes and cognitive decline long before it is diagnosed. Oxidative stress induced by Reactive Oxygen Species (ROS) has been implicated as a contributing factor to Alzheimer's disease. ROS attack on proteins can lead to protein-bound carbonyl by oxidation of the amino acid side group. Protein carbonyl formation is increased in severely affected regions of the AD brain and may be an early event in the neurodegenerative process. This is considered a marker of oxidative stress in Alzheimer's disease. Although carbonylated proteins have been strongly implicated in the aging brain and pathogenesis of AD, the identities of specific protein targets of oxidative damage remain largely unknown.
The overall goal of the research proposed in this application is to identify the major carbonylated proteins in the aging brain that contribute to the pathogenesis of Alzheimer's disease (AD). It is also a goal of the study to determine which neurological pathways and brain functions are affected by the presence of these carbonylated proteins. To achieve this goal, we will develop a "micro-fluidic device" to enrich and process a minute amount of oxidatively damaged (e.g. carbonylated) proteins prior to mass spectrometry and bioinformatics analysis. The development of this microfluidic device will simplify the processing of complex proteomic samples by combining multiple proteomic steps and allow for the identification of carbonylated proteins from small samples such as brain tissue slices taken from various brain regions of transgenic mouse models with mild cognitive impairment, and Alzheimer's disease (AD). This will help to understand the longitudinal change in the identities and relative ratios of specific protein targets of oxidative damage. Furthermore, advanced bioinformatic analysis of the proteomic data will be performed using the (ingenuity pathway analysis) IPA tool. Ingenuity pathway analysis will provide a unique look at cellular pathways and functions potentially affected by carbonylation in the different developmental stages of AD. By combining the micro-fluidic device, IPA and isobaric tags for relative and absolute quantification (iTRAQ)-based proteomic techniques, a deeper understanding of the complex proteome, signaling pathways and functional group changes that occur in a mouse model of AD should emerge, which could potentially illuminate novel therapeutic avenues for the treatment of AD and other neurodegenerative disorders.