Stroke places a significant burden on our patients and their families, and has a major economic impact on society. While advances in the areas of revascularization have improved our ability to treat this devastating disorder, the development of neuroprotective drugs targeting the delayed neuron loss has not kept a pace. Protective strategies that target the acute phase of necrotic cell loss after stroke have failed in clinical trials. Our belief, which is supported by evidence from imaging data in humans, is that these Interventions fail to address the wave of neuronal cell death that matures during the hours to days after the inciting stimulus. We seek to identify new molecular targets and therapies that can alter transcriptional responses in endangered brain tissue, which without intervention Is destined to die. We envision that therapies based on our discoveries would complement Intravenous or Intra-arterial thrombolysis protocols after focal stroke, and In patients who have sustained global anoxic brain injury after cardiac arrest. Hypoxia is a key physiologic component of stroke, and our studies indicate that the endoplasmic reticulum (ER) plays a major role in stimulating de novo adaptive and pathological gene expression in neurons. We have identified a cluster of bZIP transcription factors that are activated in other paradigms involving ER stress. One factor of particular Interest is the protein Chop-10 (ddit3/gadd153). While most published studies indicate Chop serves a pathological role, our data suggests Chop promotes adaptive signaling In the face of hypoxic challenge. We also find that Chop is subject to post-translational modification (PTM), and that Chop may tie required for BDNF induced neuroprotection. In this updated ROO proposal we focus on understanding the factors governing Chop's ability to either protect or trigger cell death programs in neurons. Discoveries made during the K99 phase have led us to define the upstream signals linking BDNF mediated protection with Chop activation. These studies buikj upon progress made during the K99 phase and use a variety of molecular genetic tools to study Chop-10 biology in stroke-relevant experimental paradigms. We anticipate that our results will aid in the identification of novel and tractable therapeutics for stroke.

Public Health Relevance

The currently available therapeutic options for stroke are suboptimal in that they fail to address the delayed, genetically programmed phase of neruon cell death induced by ischemia. We are using a molecular genetic approach to studying the role of the endoplasmic reticulum response transcription factor Chop-10 in this process. We anticipate our findings will highlight novel neuroprotective strategies for this disorder.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Transition Award (R00)
Project #
4R00NS060764-03
Application #
8032665
Study Section
Special Emphasis Panel (NSS)
Program Officer
Jacobs, Tom P
Project Start
2008-04-01
Project End
2013-03-31
Budget Start
2010-04-01
Budget End
2011-03-31
Support Year
3
Fiscal Year
2010
Total Cost
$249,000
Indirect Cost
Name
University of Rochester
Department
Neurology
Type
Schools of Dentistry
DUNS #
041294109
City
Rochester
State
NY
Country
United States
Zip Code
14627
Rininger, A; Wayland, A; Prifti, V et al. (2012) Assessment of CA1 injury after global ischemia using supervised 2D analyses of nuclear pyknosis. J Neurosci Methods 207:181-8
Rininger, A; Dejesus, C; Totten, A et al. (2012) MKP-1 antagonizes C/EBPýý activity and lowers the apoptotic threshold after ischemic injury. Cell Death Differ 19:1634-43
Halterman, Marc W (2011) An improved method for the study of apoptosis-related genes using the tet-on system. J Biomol Screen 16:332-7
Segel, George B; Halterman, Marc W; Lichtman, Marshall A (2011) The paradox of the neutrophil's role in tissue injury. J Leukoc Biol 89:359-72
Halterman, Marc W; Gill, Molly; DeJesus, Chris et al. (2010) The endoplasmic reticulum stress response factor CHOP-10 protects against hypoxia-induced neuronal death. J Biol Chem 285:21329-40