Resveratrol Increases Glutamate Uptake, Glutathione Content, and S100B Secretion in Cortical Astrocyte Cultures

Abstract

Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a polyphenol present in grapes and red wine, which has antioxidant properties and a wide range of other biological effects. In this study, we investigated the effect of resveratrol, in a concentration range of 10-250 microM, on primary cortical astrocytes; evaluating cell morphology, parameters of glutamate metabolism such as glutamate uptake, glutamine synthetase activity and glutathione total content, and S100B secretion. Astrocyte cultures were prepared of cerebral cortex from neonate Wistar rats. Morphology was evaluated by phase-contrast microscopy and immunocytochemistry for glial fibrillary acidic protein (GFAP). Glutamate uptake was measured using L-[2,3-3H]glutamate. Glutamine synthetase and content of glutathione were measured by enzymatic colorimetric assays. S100B content was determined by ELISA. Typical polygonal morphology becomes stellated when astrocyte cultures were exposed to 250 microM resveratrol for 24 h. At concentration of 25 microM, resveratrol was able to increase glutamate uptake and glutathione content. Conversely, at 250 microM, resveratrol decreased glutamate uptake. Unexpectedly, resveratrol at this high concentration increased glutamine synthetase activity. Extracellular S100B increased from 50 microM upwards. Our findings reinforce the protective role of this compound in some brain disorders, particularly those involving glutamate toxicity. However, the underlying mechanisms of these changes are not clear at the moment and it is necessary caution with its administration because elevated levels of this compound could contribute to aggravate these conditions.

A metabolic perturbation by U0126 identifies a role for glutamine in resveratrol-induced cell death

“…The proposed requirement for glutamine metabolism as a cofactor for resveratrol-induced cell death may relate to research reports in areas other than cancer, specifically to the ability of resveratrol to inhibit glutamate toxicity 76 and adipogenesis. 77 Glutamate toxicity in neurons results from elevated glutamate concentrations in the synaptic cleft and is modulated through interactions with astrocytes.…”

“…77 Glutamate toxicity in neurons results from elevated glutamate concentrations in the synaptic cleft and is modulated through interactions with astrocytes. 76 Inhibiting glucose or glutamine uptake may alter the downstream flux of glutamate within this dynamic system. Glutamine uptake is also critical in adipocytes, which need oxaloacetate replenished in the TCA cycle to drive citrate release for production of fatty acids and triglyceride storage.…”

Neuroprotective Effect of Resveratrol Against Glutamate-Induced Excitotoxicity

“…For example, Res protected against neurotoxic effects and antagonized the [Ca2+]i elevation produced by excess Glu concentrations in cerebrospinal fluid from amyotrophic lateral sclerosis patients, primary cultured rat cortical cells and the murine hippocampal cell line HT 22 [11][12][13]. Recent studies have reported that Res increased Glu uptake, glutathione content and S 100B secretion in primary cortical astrocytes [14], and reduced Glu-induced radical formation in murine brain cultures [15]. Res and capsaicin combined enhance neuroprotection against Glu-induced toxicity in mouse cerebral cortical neurons, implying a useful therapeutic method for treating neurodegenerative disorders [16].…”

“…Res inhibits the increase of extracellular Glu levels induced by stretch injuries by enhancing the Glu transporter, thus increasing Glu uptake, glutathione content, glutamine synthetase activity and S 100B (a neurotrophic cytokine) secretion in cortical astrocyte cultures and C6 glioma cells [14,18,19]. Moreover, Res could directly inhibit Glu release in rat cerebrocortical nerve terminals by decreasing mitogen-activated protein kinase activation and, subsequently suppressing voltage-dependent Ca2+ channel activity [20].…”

Avaliação temporal da expressão gênica e proteica de S100b no encéfalo de ratos neonatos submetidos à anóxia.

“…Em astrócitos, é evidenciado que agonistas do receptor de serotonina (5-HT 1A ), glutamato, antidepressivos, risperidona, antioxidantes naturais, adenosina, interleucina-1 beta (IL-1β), fator de necrose tumoral alfa (TNFα), MTPT, ácido lisofosfatídico, complexo da desidrogenase dos α-cetoácidos de cadeia ramificada, estresse metabólico, estresse oxidativo e alterações extracelulares dos níveis de cálcio e potássio são estímulos que induzem a liberação da proteína S100β (Abib et al, 2007;de Almeida et al, 2007;de Souza et al, 2009;Donato et al, 2009;Edwards, Robinson, 2006;Funchal et al, 2007;Iuvone et al, 2007;Nardin et al, 2009;Quincozes-Santos et al, 2008;Sorci et al, 2011;Tramontina et al, 2008).…”