Targeting C/EBP homologous protein with siRNA attenuates cerebral vasospasm after experimental subarachnoid hemorrhage.

Abstract

Endothelial apoptosis plays a major role in the development of cerebral vascular spasm after subarachnoid hemorrhage (SAH). C/EBP homologous protein (CHOP) orchestrates apoptosis in a variety of cell types in response to endoplasmic reticulum (ER) stress, implicated in the brain injury after SAH. However, the role of CHOP in the mechanism of cerebral vasospasm (CVS) after SAH remains unexplored. The aim of this study was to evaluate the effect of CHOP silencing on endothelial apoptosis and CVS following subarachnoid hemorrhage in the rat. The study was conducted on 65 rats and employed endovascular perforation model of SAH. CHOP siRNAs were injected 24 h prior to the hemorrhage. At 72 h after SAH brains with basilar arteries (BA) were collected from euthanized rats for laboratory investigations. Triple fluorescence stain revealed expression of CHOP in cerebral vascular endothelia after SAH. Marked reduction of CHOP protein and the reduction of its downstream signaling effectors, bim and caspase-3, were found in BA with Western blot analysis. CHOP silencing reduced number of apoptotic endothelial cells in BA, and increased BA diameter after SAH. The amelioration of CVS was associated with reduced neuronal injury in cerebral tissues. In conclusion, CHOP siRNA treatment can effectively combat apoptotic mechanisms of cerebral vasospasm set in motion by subarachnoid bleeding.

• Authors: Zhaohui He, Robert P Ostrowski, Xiaochuan Sun, Qingyi Ma, Jiping Tang, John H Zhang
• Journal: Experimental neurology (Exp Neurol) Vol. 238 Issue 2 Pg. 218-24 (Dec 2012) ISSN: 1090-2430 [Electronic] United States
• PMID: 22944263 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2012 Elsevier Inc. All rights reserved.

Chemical References

• Apoptosis Regulatory Proteins
• Bcl-2-Like Protein 11
• Bcl2l11 protein, rat
• Membrane Proteins
• Proto-Oncogene Proteins
• Proto-Oncogene Proteins c-bcl-2
• RNA, Small Interfering
• von Willebrand Factor
• Transcription Factor CHOP
• Caspase 3

Topics

• Analysis of Variance
• Animals
• Apoptosis Regulatory Proteins (metabolism)
• Basilar Artery (pathology)
• Bcl-2-Like Protein 11
• Caspase 3 (metabolism)
• Cell Count
• Disease Models, Animal
• Endothelial Cells (drug effects, metabolism)
• Endothelium (drug effects, metabolism, pathology)
• In Situ Nick-End Labeling
• Male
• Membrane Proteins (metabolism)
• Proto-Oncogene Proteins (metabolism)
• Proto-Oncogene Proteins c-bcl-2 (metabolism)
• RNA, Small Interfering (therapeutic use)
• Rats
• Rats, Sprague-Dawley
• Subarachnoid Hemorrhage (complications)
• Transcription Factor CHOP (genetics, metabolism)
• Vasospasm, Intracranial (etiology, pathology, prevention & control)
• von Willebrand Factor (metabolism)