Epilepsy is a curable disease, but nearly one out of four patients develops seizures that are resistant to anti- epileptic medications. Seizures are neurological conditions characterized by abnormal brain waves and decreased inhibition. The fundamental determinant of inhibition in the brain is the protein KCC2, which dictates how key anti-epileptic drug targets work. Without KCC2 these targets would no longer function properly, and consequently, neither would the first- and second-line anti-epileptic drug therapies. KCC2 was only recently found to be severely diminished in the brains of people suffering from drug-resistant epilepsy. This proposal represents the first attempt to unequivocally identify the loss o this protein as the common feature of drug- resistant seizures. Given the fundamental role of this protein, it is vital that the proposed experiments are completed for the benefit of people suffering from this as yet incurable disorder. The project will consist of an array of molecular, electrophysiological, and genetic experiments to confirm the hypothesized role of KCC2 in animal models of drug-resistant seizures. The first project aim utilizes a new strategy to examine impaired KCC2 function on the molecular scale. This will demonstrate that a deficit in KCC2 function impedes inhibitory signaling between brain cells. The second project aim utilizes a model of drug-resistant seizures in animal brain tissue to directly demonstrate that the deficit in KCC2 function causes this disorder. This will be the first demonstration of this process in any model of drug-resistant seizures. The final project aim will directly address a longstanding unanswered question in medicine. Physicians have known for years that drug-resistant seizures develop with time, slowly and sometimes rapidly evolving from a state that can be treated into one that cannot. These experiments will be the first demonstration in a living animal brain that the progressive loss of KCC2 function underlies the development of these drug-resistant seizures. Such a finding would suggest that rescuing KCC2 function could restore the therapeutic effectiveness of current anti-epileptic drugs. The overarching research objective is to lay the foundation for immediate testing of a novel therapeutic strategy that targets KCC2 function to improve the quality of life of those suffering from drug-resistant seizures.

Public Health Relevance

The aim of this proposal is to determine the underlying mechanism of drug-resistant seizures. Recent evidence revealed that a key protein in the brain is diminished in patients with drug-resistant seizures. This project is intended ultimately to lead to new therapies that target this protein.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21NS080064-02
Application #
8608616
Study Section
Clinical Neuroplasticity and Neurotransmitters Study Section (CNNT)
Program Officer
Whittemore, Vicky R
Project Start
2013-02-01
Project End
2015-01-31
Budget Start
2014-02-01
Budget End
2015-01-31
Support Year
2
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Tufts University
Department
Neurosciences
Type
Schools of Medicine
DUNS #
City
Boston
State
MA
Country
United States
Zip Code
02111
Wobst, Heike J; Wesolowski, Steven S; Chadchankar, Jayashree et al. (2017) Cytoplasmic Relocalization of TAR DNA-Binding Protein 43 Is Not Sufficient to Reproduce Cellular Pathologies Associated with ALSIn vitro. Front Mol Neurosci 10:46
Conway, Leslie C; Cardarelli, Ross A; Moore, Yvonne E et al. (2017) N-Ethylmaleimide increases KCC2 cotransporter activity by modulating transporter phosphorylation. J Biol Chem 292:21253-21263
Modgil, Amit; Parakala, Manasa L; Ackley, Michael A et al. (2017) Endogenous and synthetic neuroactive steroids evoke sustained increases in the efficacy of GABAergic inhibition via a protein kinase C-dependent mechanism. Neuropharmacology 113:314-322
Kang, Ji-Yong; Chadchankar, Jayashree; Vien, Thuy N et al. (2017) Deficits in the activity of presynaptic ?-aminobutyric acid type B receptors contribute to altered neuronal excitability in fragile X syndrome. J Biol Chem 292:6621-6632
Trattnig, Sarah M; Gasiorek, Agnes; Deeb, Tarek Z et al. (2016) Copper and protons directly activate the zinc-activated channel. Biochem Pharmacol 103:109-17
Nakamura, Yasuko; Morrow, Danielle H; Modgil, Amit et al. (2016) Proteomic Characterization of Inhibitory Synapses Using a Novel pHluorin-tagged ?-Aminobutyric Acid Receptor, Type A (GABAA), ?2 Subunit Knock-in Mouse. J Biol Chem 291:12394-407
Vien, Thuy N; Moss, Stephen J; Davies, Paul A (2016) Regulating the Efficacy of Inhibition Through Trafficking of ?-Aminobutyric Acid Type A Receptors. Anesth Analg 123:1220-1227
Kelley, Matthew R; Deeb, Tarek Z; Brandon, Nicholas J et al. (2016) Compromising KCC2 transporter activity enhances the development of continuous seizure activity. Neuropharmacology 108:103-10
Walker, Kendall R; Modgil, Amit; Albrecht, David et al. (2016) Genetic Deletion of the Clathrin Adaptor GGA3 Reduces Anxiety and Alters GABAergic Transmission. PLoS One 11:e0155799
Mircsof, Dennis; Langouët, Maéva; Rio, Marlène et al. (2015) Mutations in NONO lead to syndromic intellectual disability and inhibitory synaptic defects. Nat Neurosci 18:1731-6

Showing the most recent 10 out of 31 publications