Ataxia-telangiectasia (A-T) is a profoundly destructive childhood disorder resulting from mutation of a gene encoding a member of the PI3 kinase family. The gene, named ataxia- telangiectasia mutated (ATM) is a recognized component of the response mechanism to DNA double strand breaks. Yet, the consequences of ATM mutation include dramatic neurological deficiencies, and while some features of A-T can be explained by a faulty response to DNA damage, it is hard to fully account for the neurological aspects of the disease on this basis. The core hypothesis of this application is that there is a nervous system-specific form of ATM that is cytoplasmic. In this location, it serves as a serine-threonine kinase but equally as a chaperone protein that nucleates a complex of proteins that includes vesicle proteins such as synapsin-I and VAMP2. We propose that it is the failure of the functions associated with cytoplasmic ATM that leads to many of the neurological symptoms of A-T. We will explore this hypothesis in a two-part strategy.
Our first aim i s to expand our understanding of the role of ATM as a nucleocytoplasmic protein in neurons, and to uncover the unique functions that are enabled by its dual localization. We will explore how cytoplasmic ATM contributes to neuronal function on its own, and how it coordinates its action with its counterpart in the nucleus. Our outcome measures will include dendritic morphology, synaptic physiology, cell cycle regulation and cell survival. The second part of our strategy will be to develop strong pre-clinical platforms, both in vivo and in vitro, to test several agents currently under study in the clinic. We provide preliminary data showing that the well-described diversity of phenotype in human A-T is mimicked successfully in the mouse, provided that the correct set of alleles is chosen for analysis. We will use this newly expanded view of the mouse models to test the involvement of ATM in the neuronal response to stresses such as excitotoxicity, DNA damage and oxidative stress. Using the same outcome measures as above we will specifically test wild type and Atm- deficient cells for their response to stress and compare anti-oxidant and anti-inflammatory strategies for the potency as protective agents. Successful leads will be followed by in vivo trials comparing wild type with two different Atm mutations and their compound heterozygote. In a final series of pilot experiments we will explore whether ATM malfunction plays a role in other neurodegenerative disease. In the aggregate these studies offer a new look at the neurological deficits associated with A-T and, through the development of in vitro and in vivo model systems, brings fresh momentum to the discovery of treatments for this devastating condition.

Public Health Relevance

The dynamic behavior of the ATM protein in the neuronal cytoplasm and the discovery of its intimate association with proteins involved in synaptic vesicle behavior argue that there are facets of the neurobiology of ataxia-telangiectasia that remain to be discovered. The experiments proposed will bring new insights and offer fresh clues to the progress of ataxia-telangiectasia and other neurological diseases, of which Alzheimer's disease is only one example. The exploration of these phenomena will thus have significant value for our basic biological understanding of brain function as well as its malfunction in a number of different clinically relevant situations.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS071022-02
Application #
8110566
Study Section
Neural Oxidative Metabolism and Death Study Section (NOMD)
Program Officer
Tagle, Danilo A
Project Start
2010-07-15
Project End
2015-04-30
Budget Start
2011-05-01
Budget End
2012-04-30
Support Year
2
Fiscal Year
2011
Total Cost
$404,535
Indirect Cost
Name
Rutgers University
Department
Anatomy/Cell Biology
Type
Schools of Arts and Sciences
DUNS #
001912864
City
New Brunswick
State
NJ
Country
United States
Zip Code
08901
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Chen, Jianmin; Chen, Yanping; Vail, Graham et al. (2016) The impact of glutamine supplementation on the symptoms of ataxia-telangiectasia: a preclinical assessment. Mol Neurodegener 11:60
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Vail, Graham; Cheng, Aifang; Han, Yu Ray et al. (2016) ATM protein is located on presynaptic vesicles and its deficit leads to failures in synaptic plasticity. J Neurophysiol 116:201-9
Hui, Chin Wai; Herrup, Karl (2015) Individual Cytokines Modulate the Neurological Symptoms of ATM Deficiency in a Region Specific Manner eNeuro 2:
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Herrup, Karl (2013) Post-mitotic role of the cell cycle machinery. Curr Opin Cell Biol 25:711-6

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