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Glutathione-Induced Calcium Shifts in Chick Retinal Glial Cells

2016; Public Library of Science; Volume: 11; Issue: 4 Linguagem: Inglês

10.1371/journal.pone.0153677

1932-6203

Hércules Rezende Freitas, Gabriel Araújo e Silva Ferraz, Gustavo C. Ferreira, Victor Túlio Ribeiro‐Resende, Luciana B. Chiarini, José Luíz Martins do Nascimento, Karen Renata Herculano Matos Oliveira, Tiago de Lima Pereira, Leonardo Gomes Braga Ferreira, Regina Célia Cussa Kubrusly, Robson Xavier Faria, Anderson Manoel Herculano, Ricardo Augusto de Melo Reis,

Retinal Development and Disorders

Neuroglia interactions are essential for the nervous system and in the retina Müller cells interact with most of the neurons in a symbiotic manner. Glutathione (GSH) is a low-molecular weight compound that undertakes major antioxidant roles in neurons and glia, however, whether this compound could act as a signaling molecule in neurons and/or glia is currently unknown. Here we used embryonic avian retina to obtain mixed retinal cells or purified Müller glia cells in culture to evaluate calcium shifts induced by GSH. A dose response curve (0.1–10mM) showed that 5–10mM GSH, induced calcium shifts exclusively in glial cells (later labeled and identified as 2M6 positive cells), while neurons responded to 50mM KCl (labeled as βIII tubulin positive cells). BBG 100nM, a P2X7 blocker, inhibited the effects of GSH on Müller glia. However, addition of DNQX 70μM and MK-801 20μM, non-NMDA and NMDA blockers, had no effect on GSH calcium induced shift. Oxidized glutathione (GSSG) at 5mM failed to induce calcium mobilization in glia cells, indicating that the antioxidant and/or structural features of GSH are essential to promote elevations in cytoplasmic calcium levels. Indeed, a short GSH pulse (60s) protects Müller glia from oxidative damage after 30 min of incubation with 0.1% H2O2. Finally, GSH induced GABA release from chick embryonic retina, mixed neuron-glia or from Müller cell cultures, which were inhibited by BBG or in the absence of sodium. GSH also induced propidium iodide uptake in Müller cells in culture in a P2X7 receptor dependent manner. Our data suggest that GSH, in addition to antioxidant effects, could act signaling calcium shifts at the millimolar range particularly in Müller glia, and could regulate the release of GABA, with additional protective effects on retinal neuron-glial circuit.