title: Enhanced glutathione efflux from astrocytes in culture by low extracellular Ca2+ and curcumin.
abstract: Efflux of glutathione (GSH) from astrocytes has been suggested as a key factor for neuroprotection by astrocytes. Here we evaluated if the Nrf2 activator curcumin affects basal and stimulated (Ca(2+) omission) GSH efflux from cultures of astroglial cells. Stimulated efflux of GSH was observed at medium concentration of 0, 0.1 mM Ca(2+), but not at 0.2 or 0.3 mM Ca(2+). Astroglia treated with 30 microM curcumin increased the cellular content of GSH in parallel with elevated basal and stimulated efflux. Conversely treatment with buthionine sulfoximine lowered efflux of GSH. The efflux stimulated by Ca(2+)- omission was not affected by the P2X7-receptor antagonist Blue Brilliant G (100 nM) or the pannexin mimetic/blocking peptide (10)Panx1 but inhibited by the gap junction blocker carbenoxolone (100 microM) and a hemichannel blocker Gap26 (300 microM). RNAi directed against Nrf2 partly inhibited the effect of curcumin. The results show that elevated cellular GSH by curcumin treatment enhance efflux from astroglial cells, a process which appear to be a prerequisite for astroglial mediated neuroprotection.
authors.affiliation: Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden. malin.stridh@physiol.gu.se
authors.forename: Malin H
authors.initials: MH
authors.lastname: Stridh
authors.forename: Fernando
authors.initials: F
authors.lastname: Correa
authors.forename: Christina
authors.initials: C
authors.lastname: Nodin
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Weber
authors.forename: Fredrik
authors.initials: F
authors.lastname: Blomstrand
authors.forename: Michael
authors.initials: M
authors.lastname: Nilsson
authors.forename: Mats
authors.initials: M
authors.lastname: Sandberg
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003474:Curcumin / Q000494:pharmacology*; D005110:Extracellular Space / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D005721:Glutamate-Cysteine Ligase / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D005978:Glutathione / Q000378:metabolism*; D006624:Hippocampus / Q000166:cytology; D051267:NF-E2-Related Factor 2 / Q000819:agonists / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D051267:NF-E2-Related Factor 2; D034741:RNA, Small Interfering; D019328:Buthionine Sulfoximine; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione; D003474:Curcumin; D002118:Calcium