Brain trauma induces inflammation in both the endothelium and the brain parenchyma, collectively termed the neurovascular unit. While neurons die quickly by necrosis following traumatic brain injury (TBI), a vicious cycle of inflammation in endothelial cells exacerbates the injury. In activated endothelial cells, excessive superoxide reacts with nitric oxide (NO) to form peroxynitrite. At high levels following TBI, peroxynitrite is involved in blood brain barrier (BBB) leakage, altered enzymatic functions, and neurobehavior impairment. It activates AMP Kinase (AMPK), which in turn may up regulate the superoxide-producing activity of endothelial nitric oxide synthase (eNOS), and thus maintains a vicious cycle of neuroinflammatory secondary injury. The nitrosylating agent S-nitrosoglutathione (GSNO) is capable of reducing the levels of peroxynitrite and inhibiting the activity of AMPK. It also restores the levels of glutathione and protects the integrity of the neurovascular unit. Therefore, this study will investigate whether GSNO treatment ameliorates TBI-induced neuroinflammatory damage to the neurovascular unit via nitrosylation. We hypothesize that GSNO blocks the vicious AMPK/eNOS/peroxynitrite cycle, thus reducing the neurovascular injury and aiding functional recovery in TBI.
In Specific Aim 1, pharmacological agents (GSNO, a peroxynitrite scavenger, and an AMPK selective inhibitor) will be used as therapeutic tools to dissect the regulation of AMPK and amelioration of TBI in a controlled cortical impact mouse model.
In Specific Aim 2, the elucidated mechanisms will be further examined and validated using AMPK alpha 1/2 knockout mice, AMPK alpha over-expressing transgenic mice, and wild type mice.
In Specific Aim 3, we will determine whether GSNO-mediated nitrosylation of either AMPK or its upstream kinase LKB1 is responsible for the inhibition of aberrant eNOS activity and the reduced formation of peroxynitrite. The complementary pharmacological and genetic approach will determine the role of AMPK in TBI. GSNO, unlike conventional NO donors, is a non-toxic endogenous NO modulator and nitrosylating agent. Understanding S-nitrosylation mechanism and the unique AMPK/eNOS/peroxynitrite pathway may lead to new strategies for the treatment of neuroinflammatory brain trauma that target not only its neuronal consequences but also its vascular causes and exacerbations.

Public Health Relevance

As a consequence of war, accidents and sport injury, an increasing number of young Americans are suffering from brain trauma. Current treatment is limited to supportive care because the neuroinflammatory mechanisms of traumatic brain injury are not well understood. The success of this proposed mechanistic intervention using S-nitrosoglutathione would provide a novel neurovascular approach to treating brain trauma.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS072511-04
Application #
8652841
Study Section
Clinical Neuroimmunology and Brain Tumors Study Section (CNBT)
Program Officer
Bellgowan, Patrick S F
Project Start
2011-05-01
Project End
2016-04-30
Budget Start
2014-05-01
Budget End
2015-04-30
Support Year
4
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Medical University of South Carolina
Department
Pathology
Type
Schools of Medicine
DUNS #
City
Charleston
State
SC
Country
United States
Zip Code
29403
Khan, Mushfiquddin; Dhammu, Tajinder S; Baarine, Mauhamad et al. (2018) GSNO promotes functional recovery in experimental TBI by stabilizing HIF-1?. Behav Brain Res 340:63-70
Choi, Seungho; Won, Je-Seong; Carroll, Steven L et al. (2018) Pathology of nNOS-Expressing GABAergic Neurons in Mouse Model of Alzheimer's Disease. Neuroscience 384:41-53
Kim, Jinsu; Choi, Seungho; Saxena, Nishant et al. (2017) Regulation of STAT3 and NF-?B activations by S-nitrosylation in multiple myeloma. Free Radic Biol Med 106:245-253
Samuvel, Devadoss J; Shunmugavel, Anandakumar; Singh, Avtar K et al. (2016) S-Nitrosoglutathione ameliorates acute renal dysfunction in a rat model of lipopolysaccharide-induced sepsis. J Pharm Pharmacol 68:1310-9
Khan, Mushfiquddin; Dhammu, Tajinder S; Matsuda, Fumiyo et al. (2016) Targeting the nNOS/peroxynitrite/calpain system to confer neuroprotection and aid functional recovery in a mouse model of TBI. Brain Res 1630:159-70
Won, Je-Seong; Annamalai, Balasubramaniam; Choi, Seungho et al. (2015) S-nitrosoglutathione reduces tau hyper-phosphorylation and provides neuroprotection in rat model of chronic cerebral hypoperfusion. Brain Res 1624:359-369
Kaliyaperumal, Kolanjiappan; Sharma, Anand K; McDonald, Daniel G et al. (2015) S-Nitrosoglutathione-mediated STAT3 regulation in efficacy of radiotherapy and cisplatin therapy in head and neck squamous cell carcinoma. Redox Biol 6:41-50
Khan, Mushfiquddin; Dhammu, Tajinder S; Matsuda, Fumiyo et al. (2015) Promoting endothelial function by S-nitrosoglutathione through the HIF-1?/VEGF pathway stimulates neurorepair and functional recovery following experimental stroke in rats. Drug Des Devel Ther 9:2233-47
Shunmugavel, Anandakumar; Khan, Mushfiquddin; Hughes Jr, Francis M et al. (2015) S-Nitrosoglutathione protects the spinal bladder: novel therapeutic approach to post-spinal cord injury bladder remodeling. Neurourol Urodyn 34:519-26
Khan, Mushfiquddin; Dhammu, Tajinder S; Matsuda, Fumiyo et al. (2015) Blocking a vicious cycle nNOS/peroxynitrite/AMPK by S-nitrosoglutathione: implication for stroke therapy. BMC Neurosci 16:42

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