Traumatic brain injury (TBI) is a leading cause of death and disability in the human population worldwide, with approximately 2 million reported TBI events occurring in the US annually. Significant cell death occurs within the first days following TBI, resulting in a substantial release of brain proteins and their breakdown products into biofluids such as cerebrospinal fluid (CSF) and circulating blood as facilitated by the compromised brain blood barrier. We recently performed a pilot unbiased investigation to examine if post-TBI patient serum contains autoantibody reactive to one or more brain-specific proteins after TBI. Rather unexpectedly, we found that a significant portion of TBI patients' subacuet sera contains a dominant autoantibody response to a major astrocyte protein GFAP that is proteolytically modified as GFAP breakdown product (GFAP-BDP). We hypothesize that such protease modified GFAP could breakdown the self-tolerance and serve as the dominant autoantigen to trigger autoimmune response following TBI. To examine this hypothesis, we propose to conduct a translational study that combines testing clinical samples and conducting mouse autoimmune studies in vivo as the following:
Specific Aim 1 will identify and characterize protease-modified GFAP and accompanied autoantibodies in human CSF and sera post-TBI.
Specific Aim 2 will examine systemic immune response and brain pathological consequences in mice following active GFAP-BDP antigen immunization. Lastly, Specific Aim 3 will explore mouse pathological changes as a result of anti-GFAP-BDP autoimmunity in conjunction with experimental TBI. The data generated would provide valuable insight into the pathogenic mechanisms of TBI and likely to support potential development of treatment strategies aimed at reducing the public health burden that follows TBI.

Public Health Relevance

An unexpectedly robust autoimmune response is evoked against a major glial structural protein (GFAP) in a subset of TBI patients. The proposed study will examine, validate and explore the novel modified autoantigen and its consequence following TBI. The outcome of this proposal would provide valuable insight into the pathogenic mechanisms of TBI and likely to support potential development of treatment strategies aimed at reducing the public health burden that follows TBI.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21NS085455-02
Application #
8843988
Study Section
Acute Neural Injury and Epilepsy Study Section (ANIE)
Program Officer
Bellgowan, Patrick S F
Project Start
2014-05-01
Project End
2017-04-30
Budget Start
2015-05-01
Budget End
2017-04-30
Support Year
2
Fiscal Year
2015
Total Cost
Indirect Cost
Name
University of Florida
Department
Psychiatry
Type
Schools of Medicine
DUNS #
969663814
City
Gainesville
State
FL
Country
United States
Zip Code
32611