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Updated: Apr 9, 2026
Evaluating Cell Death Signaling by Immunofluorescence in a Rat Model of Ischemic Stroke
Published on: January 3, 2025
Calpain-Dependent ErbB4 Cleavage Is Involved in Brain Ischemia-Induced Neuronal Death
Ying-mei Lu1,2, Yin-ping Gao1, Rong-rong Tao3
1School of Medicine, Zhejiang University City College, Hangzhou, China.
Abstract:
Disturbance of neuregulin-1β/ErbB4 signaling is considered to be associated with brain ischemia, but the mechanisms of this disruption are largely unknown. In the present study, we provide evidence that degradation of ErbB4 is involved in neuronal cell death in response to ischemia. Our data showed that the application of neuregulin-1β provided significant protection against oxygen-glucose deprivation (OGD)-induced neuronal death as detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, annexin V/propidium iodide flow cytometry analysis and terminal deoxynucleotidyl transferase (TdT) dUTP nick end labeling (TUNEL) staining. Furthermore, neuregulin-1β treatment significantly reduced the infarct volume of ischemic mice, and this result was not seen in the ErbB4 knockout mice. We found that brain ischemia induced the breakdown of ErbB4 in a time-dependent manner in vivo, but not that of ErbB2. In vitro studies further indicated that recombinant calpain induced the cleavage of ErbB4 in a dose-dependent way, whereas the calpain inhibitor significantly reduced the OGD-induced ErbB4 breakdown. Additionally, OGD-induced apoptosis was partially abolished by transfection with the ErbB4E872K mutant. Taken together, neuregulin-1β elicits its neuroprotective effect in an ErbB4-dependent manner, and the cleavage of ErbB4 by calpain contributes to a neuronal cell death cascade during brain ischemia.
Insights
Neuregulin-1β protects against brain ischemia by maintaining ErbB4 integrity. Calpain-mediated ErbB4 cleavage contributes to neuronal death during ischemic events, highlighting a key mechanism in stroke pathology.
Area of Science:
- Neuroscience
- Molecular Biology
- Pathology
Background:
- Neuregulin-1β/ErbB4 signaling is implicated in brain ischemia, but its disruption mechanisms remain unclear.
- Neuronal cell death during ischemia is a critical factor in stroke outcomes.
- Understanding the molecular pathways involved in ischemic neuronal injury is essential for developing effective treatments.
Purpose of the Study:
- To investigate the role of ErbB4 degradation in neuronal cell death following brain ischemia.
- To elucidate the protective mechanisms of neuregulin-1β in ischemic conditions.
- To identify the specific enzymes involved in ErbB4 breakdown during ischemia.
Main Methods:
- In vitro studies using oxygen-glucose deprivation (OGD) models to induce neuronal injury.
- In vivo studies using ischemic mouse models to assess infarct volume and ErbB4 levels.
- Biochemical assays including MTT, flow cytometry, TUNEL staining, and Western blotting.
- Enzyme activity assays using recombinant calpain and calpain inhibitors.
- Genetic manipulation using ErbB4 knockout mice and ErbB4 mutant transfection.
Main Results:
- Neuregulin-1β treatment significantly protected neurons against OGD-induced death and reduced infarct volume in mice.
- ErbB4 knockout mice did not exhibit protection with neuregulin-1β treatment, confirming ErbB4 dependence.
- Brain ischemia induced time-dependent breakdown of ErbB4 in vivo.
- Calpain directly cleaved ErbB4 in vitro, and calpain inhibition reduced OGD-induced ErbB4 breakdown.
- OGD-induced apoptosis was partially reduced by transfection with an ErbB4 mutant.
Conclusions:
- Neuregulin-1β exerts neuroprotective effects against brain ischemia in an ErbB4-dependent manner.
- Calpain-mediated cleavage of ErbB4 is a significant contributor to the neuronal cell death cascade during brain ischemia.
- Targeting calpain activity or preserving ErbB4 integrity may represent novel therapeutic strategies for stroke.
