The main objective of the experiments described in this application is to develop and evaluate a highly innovative, mechanistically rational neuroprotective strategy in cerebral ischemia. During the last ten years with support from this grant, we have characterized a Zn2+-mediated apoptotic-enabling signaling pathway that culminates with the SNARE-dependent insertion of p38/Src dual phosphorylated Kv2.1-encoded K+ channels in the neuronal plasma membrane. This process results in a dramatic enhancement of delayed-rectifier K+ currents, mediating the loss of intracellular K+ required for the establishment of a permissive, optimal environment for caspase and nuclease activation in injured neurons. Although interfering with the processes responsible for the apoptotic K+ current surge can effectively block neuronal cell death, none of the upstream signaling events leading to the K+ current enhancement are specific for this pathway. In preliminary studies presented here, we show that channels lacking a SNARE binding domain do not support an apoptotic current surge. Moreover, we show that overexpression of the SNARE-binding intracellular channel domain alone is neuroprotective in vitro. We hypothesize that interfering with a cellular process that trigger the Kv2.1-mediated apoptotic K+ current surge may provides a highly specific and effective therapeutic strategy for neuroprotection in stroke and related injury. In order to adequately evaluate this hypothesis we will address the following experimental Specific Aims: First, we will characterize in detail the phosphorylation and SNARE-dependent mechanisms leading to Kv2.1-mediated apoptotic K+ current surges~ and second, we will investigate whether interfering with the SNARE/Kv2.1 interaction using cell-penetrating peptides is a viable neuroprotective strategy in a rodent stroke model. The long-term goal of our research program is to devise novel neuroprotective approaches for the treatment of stroke and related neurodegenerative conditions. The loss of intracellular K+ via a surge of Kv2.1-mediated K+ currents may constitute a ubiquitous requirement for apoptotic cell death of cortical and hippocampal neurons. As effective neuroprotective strategies to treat human neurological conditions continue to be highly elusive, conceptually innovative studies, such as targeting neuronal apoptotic K+ currents, are not only of potentially high significance, but also urgently needed.

Public Health Relevance

The research proposed in this application will help us understand the role of potassium channel function in neuronal cell death. Most importantly, research conducted during this project may reveal novel avenues for developing a new class of neuroprotective drugs to prevent brain damage during stroke and related conditions.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS043277-12
Application #
8729509
Study Section
Brain Injury and Neurovascular Pathologies Study Section (BINP)
Program Officer
Bosetti, Francesca
Project Start
2002-04-01
Project End
2018-07-31
Budget Start
2014-08-01
Budget End
2015-07-31
Support Year
12
Fiscal Year
2014
Total Cost
Indirect Cost
Name
University of Pittsburgh
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Justice, Jason A; Manjooran, Daniel T; Yeh, Chung-Yang et al. (2018) Molecular Neuroprotection Induced by Zinc-Dependent Expression of Hepatitis C-Derived Protein NS5A Targeting Kv2.1 Potassium Channels. J Pharmacol Exp Ther 367:348-355
Justice, Jason A; Schulien, Anthony J; He, Kai et al. (2017) Disruption of KV2.1 somato-dendritic clusters prevents the apoptogenic increase of potassium currents. Neuroscience 354:158-167
Yeh, Chung-Yang; Bulas, Ashlyn M; Moutal, Aubin et al. (2017) Targeting a Potassium Channel/Syntaxin Interaction Ameliorates Cell Death in Ischemic Stroke. J Neurosci 37:5648-5658
Schulien, Anthony J; Justice, Jason A; Di Maio, Roberto et al. (2016) Zn(2+) -induced Ca(2+) release via ryanodine receptors triggers calcineurin-dependent redistribution of cortical neuronal Kv2.1 K(+) channels. J Physiol 594:2647-59
Li, Dong; Yuan, Hongjie; Ortiz-Gonzalez, Xilma R et al. (2016) GRIN2D Recurrent De Novo Dominant Mutation Causes a Severe Epileptic Encephalopathy Treatable with NMDA Receptor Channel Blockers. Am J Hum Genet 99:802-816
Clemens, Katerina; Yeh, Chung-Yang; Aizenman, Elias (2015) Critical role of Casein kinase 2 in hepatitis C NS5A-mediated inhibition of Kv2.1 K(+) channel function. Neurosci Lett 609:48-52
Aizenman, Elias; Mastroberardino, Pier G (2015) Metals and neurodegeneration. Neurobiol Dis 81:1-3
He, Kai; McCord, Meghan C; Hartnett, Karen A et al. (2015) Regulation of Pro-Apoptotic Phosphorylation of Kv2.1 K+ Channels. PLoS One 10:e0129498
Hershfinkel, Michal; Ford, Dianne; Kelleher, Shannon et al. (2015) Seashells by the zinc shore: a meeting report of the International Society for Zinc Biology, Asilomar, CA 2014. Metallomics 7:1299-304
Gilad, David; Shorer, Sharon; Ketzef, Maya et al. (2015) Homeostatic regulation of KCC2 activity by the zinc receptor mZnR/GPR39 during seizures. Neurobiol Dis 81:4-13

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