Astrocyte-derived glutathione attenuates hemin-induced apoptosis in cerebral microvascular cells.
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.
Sukumari-Ramesh
Sangeetha
S
Department of Neurosurgery, Medical College of Georgia, Augusta, Georgia, USA.
Laird
Melissa D
MD
Singh
Nagendra
N
Vender
John R
JR
Alleyne
Cargill H
CH
Dhandapani
Krishnan M
KM
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
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