title: Astrocyte-derived glutathione attenuates hemin-induced apoptosis in cerebral microvascular cells.
abstract: Intracerebral hemorrhage (ICH) induces neurovascular injury via poorly defined mechanisms. The aim of this study was to determine whether gliovascular communication may restrict hemorrhagic vascular injury. Hemin, a hemoglobin by-product, concentration- and time-dependently increased apoptotic cell death in mouse bEnd.3 cells and in primary human brain microvascular endothelial cells, at least in part, via a caspase-3 dependent pathway. Cell death was preceded by a NFκB-mediated increase in inflammatory gene expression, including upregulation of inducible nitric oxide synthase (iNOS) expression and activity. Functionally, inhibition of iNOS or the addition of a peroxynitrite decomposition catalyst reduced cell death. Interestingly, co-treatment with astrocyte-conditioned media (ACM) reversed hemin-induced NFκB activation, nitrotyrosine formation, and apoptotic cell death, at least in part, via the release of the endogenous antioxidant, reduced glutathione (GSH). Prior treatment of astrocytes with the GSH-depleting agent, DL-buthionine (S,R)-sulfoximine or direct addition of diethyl maleate, a thiol-depleting agent, to ACM reversed the observed protection. In contrast, neither exogenous GSH nor the GSH precursor, N-acetylcysteine, was protective in bEnd.3 cells. Together, these data support an important role for astrocyte-derived GSH in the maintenance of oxidative balance in the vasculature and suggest therapeutic targeting of the GSH system may reduce neurological injury following ICH.
authors.affiliation: Department of Neurosurgery, Medical College of Georgia, Augusta, Georgia, USA.
authors.forename: Sangeetha
authors.initials: S
authors.lastname: Sukumari-Ramesh
authors.forename: Melissa D
authors.initials: MD
authors.lastname: Laird
authors.forename: Nagendra
authors.initials: N
authors.lastname: Singh
authors.forename: John R
authors.initials: JR
authors.lastname: Vender
authors.forename: Cargill H
authors.initials: CH
authors.lastname: Alleyne
authors.forename: Krishnan M
authors.initials: KM
authors.lastname: Dhandapani
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001205:Ascorbic Acid / Q000494:pharmacology; D001253:Astrocytes / Q000737:chemistry*; D001921:Brain / Q000166:cytology; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D003474:Curcumin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism / Q000494:pharmacology*; D006427:Hemin / Q000494:pharmacology*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D051379:Mice; D055806:Microvessels / Q000166:cytology*; D018696:Neuroprotective Agents / Q000494:pharmacology; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D030421:Peroxynitrous Acid / Q000494:pharmacology; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D013997:Time Factors
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D000975:Antioxidants; D004791:Enzyme Inhibitors; D018696:Neuroprotective Agents; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D030421:Peroxynitrous Acid; D006427:Hemin; D007770:L-Lactate Dehydrogenase; D052247:Nitric Oxide Synthase Type II; C499321:Parp1 protein, mouse; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D053148:Caspase 3; D005978:Glutathione; D003474:Curcumin; D001205:Ascorbic Acid; D000111:Acetylcysteine