Astrocyte-specific heme oxygenase-1 hyperexpression attenuates heme-mediated oxidative injury.
In prior studies, we have observed that HO activity protects astrocytes from heme-mediated injury, but paradoxically increases neuronal injury. In this study, we tested the hypothesis that an adenovirus encoding the human HO-1 gene driven by an enhanced glial fibrillary acidic protein promoter (Ad-GFAP-HO-1) would increase HO-1 expression selectively in astrocytes, and provide cytoprotection. Treatment with 100 MOI Ad-GFAP-HO-1 for 24 h resulted in HO-1 expression that was 6.4-fold higher in cultured primary astrocytes than in neurons. Astrocyte HO activity was increased by approximately fourfold over baseline, which was sufficient to reduce cell death after 24-h hemin exposure by 60%, as assessed by both MTT and LDH release assays. A similar reduction in cell protein oxidation, quantified by carbonyl assay, was also observed. These results suggest that HO-1 transgene expression regulated by an enhanced GFAP promoter selectively increases HO-1 expression in astrocytes, and is cytoprotective. Further investigation of this strategy in vivo is warranted.
Benvenisti-Zarom
Luna
L
Department of Emergency Medicine, Thomas Jefferson University, 1020 Sansom Street, Thompson Building Room 239, Philadelphia, PA 19107, USA.
Regan
Raymond F
RF
D000818:Animals; D001253:Astrocytes / Q000201:enzymology*; D001921:Brain / Q000378:metabolism / Q000503:physiopathology; D001925:Brain Damage, Chronic / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D016923:Cell Death / Q000235:genetics; D002478:Cells, Cultured; D002543:Cerebral Hemorrhage / Q000150:complications; D019610:Cytoprotection / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D005822:Genetic Vectors; D006418:Heme / Q000378:metabolism*; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D009410:Nerve Degeneration / Q000209:etiology* / Q000378:metabolism* / Q000503:physiopathology; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D011401:Promoter Regions, Genetic / Q000235:genetics; D014162:Transfection / Q000379:methods; D015854:Up-Regulation / Q000235:genetics
D006418:Heme; D051547:Heme Oxygenase-1