De novo gene expression induced by endoplasmic reticulum (ER) stress plays a decisive role in determining whether neurons live or die following global cerebral ischemia. However, the molecular mechanisms regulating the balance between protective and damaging responses originating from the ER remain unsettled. We discovered that the ER-stress factor CHOP-10, previously linked to differentiation and apoptosis, induces ischemic tolerance in cortical neurons and is activated by the potent neuroprotective brain derived neurotrophic factor (BDNF). Importantly, we also found that loss of CHOP-10 expression alters neuritic responses to ischemia in the adult hippocampus. These results suggest that CHOP-10 plays a more complex role in the neuronal response to ischemic injury that previously recognized. In this proposal we test the hypothesis that CHOP functions as an integrator of both adaptive and pathological responses. Preliminary studies reveal that post-translational modifications induced by PKC and related kinase pathways have marked effects on the stability, localization and toxicity of CHOP-10. Using in vitro culture models and the 3-vessel occlusion model of transient global ischemia, we will define the mechanism(s) and role of BDNF-CHOP coupling. Together, these experiments seek to broaden our understanding regarding the role of CHOP-10 and ER stress responses in ischemic brain injury, and identify the molecular basis for ER-stress dependent transcriptional switching. Since CHOP itself is not a typical drug target, our focus on CHOP-kinase pathways may have important translational implications. The identification of suitable targets in this network could serve as the basis for therapies designed to inhibit delayed neuronal loss after ischemic brain injury.

Public Health Relevance

In the United States an estimated 400;000 patients will suffer cardiac arrest each year; and in greater than 80% of cases a poor neurological outcome is expected; new treatment strategies are desperately needed. The current proposal focuses on a recently identified protective pathway in neurons involving the neurotrophic factor BDNF and the endoplasmic reticulum stress response factor CHOP-10. Progress in this area will enable the identification of drugs that can be used to protect the brain after cardiac arrest.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
1F31NS084672-01
Application #
8594980
Study Section
Special Emphasis Panel (ZRG1-F03A-N (20))
Program Officer
Bosetti, Francesca
Project Start
2014-01-16
Project End
Budget Start
2014-01-16
Budget End
Support Year
1
Fiscal Year
2013
Total Cost
$42,232
Indirect Cost
Name
University of Rochester
Department
Neurology
Type
Schools of Dentistry
DUNS #
041294109
City
Rochester
State
NY
Country
United States
Zip Code
14627
Quinn, Breandan R; Yunes-Medina, Laura; Johnson, Gail V W (2018) Transglutaminase 2: Friend or foe? The discordant role in neurons and astrocytes. J Neurosci Res 96:1150-1158
Yunes-Medina, Laura; Feola, Julianne; Johnson, Gail V W (2017) Subcellular localization patterns of transglutaminase 2 in astrocytes and neurons are differentially altered by hypoxia. Neuroreport 28:1208-1214