Endothelial cell-specific over-expression of endothelin-1 leads to more severe cerebral damage following transient middle cerebral artery occlusion.
Previously, we have demonstrated that mRNA expression of endothelin-1 (ET-1), a potent vasoconstrictor, is induced in astrocytes and endothelial cells after ischemic conditions, suggesting that both of these cells synthesize ET-1 under this stress condition. Furthermore, ET-1 protected primary cultured astrocytes from ischemic stress. In order to further investigate the role of endothelial ET-1 in cerebral ischemic injury, transgenic mouse lines (TET) with a transgene that included ET cDNA with SV40 polyA under tyrosine kinase with immunoglobulin and epidermal growth factor homology domain (Tie-1) promoter were used. TET mouse lines were further characterized for ET-1 over-expression in the brain. The reverse transcription-polymerase chain reaction (RT-PCR) analysis using the primers specific for transgene ET-1 showed that transgene ET-1 is only expressed in the brain from TET mice. Total expression of ET- 1 mRNA was also increased in the transgenic brain compared with the non-transgenic brain by semi-quantitative RT-PCR. In situ hybridization and immunocytochemical analyses showed that the increased ET-1 mRNA and peptide expressions were detected in endothelial cells of cerebral vessels of TET mice. Under normal conditions, the TET mice that have a slightly increased blood pressure compared with that of non-transgenic mice showed no gross morphological abnormalities in the brain. However, after transient middle cerebral artery occlusion, TET mice showed a more severe neurological deficit, and larger infarct size and volume, suggesting that over-expressing ET-1 in endothelial cells is deleterious to neuronal survival under ischemic conditions. Our present TET model will serve as an ideal model for studying the role of endothelial ET- 1 in the pathogenesis of ischemic stroke.
Leung
Justin W C
JW
Institute of Molecular Biology, The University of Hong Kong, Hong Kong SAR, China.
Ho
Maggie C Y
MC
Lo
Amy C Y
AC
Chung
Stephen S M
SS
Chung
Sookja K
SK
D000818:Animals; D001921:Brain / Q000098:blood supply* / Q000473:pathology; D016923:Cell Death; D004195:Disease Models, Animal; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000473:pathology; D006624:Hippocampus / Q000098:blood supply / Q000473:pathology; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D020244:Infarction, Middle Cerebral Artery / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009410:Nerve Degeneration / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012720:Severity of Illness Index; D015854:Up-Regulation
D019332:Endothelin-1; D012333:RNA, Messenger