title: Folic Acid Protects Against Glutamate-Induced Excitotoxicity in Hippocampal Slices Through a Mechanism that Implicates Inhibition of GSK-3β and iNOS.
abstract: Folic acid (folate) is a vitamin of the B-complex group crucial for neurological function. Considering that excitotoxicity and cell death induced by glutamate are involved in many disorders, the potential protective effect of folic acid on glutamate-induced cell damage in rat hippocampal slices and the possible intracellular signaling pathway involved in such effect were investigated. The treatment of hippocampal slices with folic acid (100 μM) significantly abrogated glutamate (1 mM)-induced reduction of cell viability measured by MTT reduction assay and inhibited glutamate-induced D-[3H]-aspartate release. To investigate the putative intracellular signaling pathways implicated in the protective effect of folic acid, we used a PI3K inhibitor, LY294002, which abolished the protective effects of folic acid against glutamate-induced cell damage and D-[3H] aspartate release. Moreover, hippocampal slices incubated with folic acid alone for 30 min presented increased phosphorylation of GSK-3β at Ser9, indicating an inhibition of the activity of this enzyme. Furthermore, folic acid in the presence of glutamate insult in hippocampal slices maintained for an additional period of 6 h in fresh culture medium without glutamate and/or folic acid induced phosphorylation of GSK-3β and β-catenin expression. In addition, glutamate-treated hippocampal slices showed increased iNOS expression that was reversed by folic acid. In conclusion, the results of this study show that the protective effect of folic acid against glutamate-induced excitotoxicity may involve the modulation of PI3K/GSK-3β/β-catenin pathway and iNOS inhibition.
authors.affiliation: Department of Biochemistry, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, 88040-900, Brazil. josiane.budni@unesc.net.|Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil. josiane.budni@unesc.net.|Laboratório de Doenças Neurodegenerativas, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil. josiane.budni@unesc.net.|Neuroscience Laboratory and Neurodegenerative Disease Laboratory, Graduate Program in Health Sciences, Academic Unit of Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, 8806-000, Brazil. josiane.budni@unesc.net.
authors.forename: Josiane
authors.initials: J
authors.lastname: Budni
authors.affiliation: Universidade do Contestado, Pharmacy School, Canoinhas, SC, 89460-000, Brazil.
authors.forename: Simone
authors.initials: S
authors.lastname: Molz
authors.affiliation: Department of Biochemistry, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, 88040-900, Brazil.
authors.forename: Tharine
authors.initials: T
authors.lastname: Dal-Cim
authors.affiliation: Department of Pharmacology and Therapeutics, Universidad Autónoma de Madrid, 28050, Madrid, Spain.|Instituto Teófilo Hernando, Universidad Autonoma de Madrid, Madrid, Spain.
authors.forename: Maria Dolores
authors.initials: MD
authors.lastname: Martín-de-Saavedra
authors.affiliation: Department of Pharmacology and Therapeutics, Universidad Autónoma de Madrid, 28050, Madrid, Spain.|Instituto Teófilo Hernando, Universidad Autonoma de Madrid, Madrid, Spain.|HIV Unit. Hospital La Paz/Autónoma University School of Medicine. IdiPAZ. Universidad Autonoma de Madrid, Departamento de Farmacologia, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Egea
authors.affiliation: Department of Pharmacology and Therapeutics, Universidad Autónoma de Madrid, 28050, Madrid, Spain.|Instituto Teófilo Hernando, Universidad Autonoma de Madrid, Madrid, Spain.|HIV Unit. Hospital La Paz/Autónoma University School of Medicine. IdiPAZ. Universidad Autonoma de Madrid, Departamento de Farmacologia, Madrid, Spain.
authors.forename: Manuela G
authors.initials: MG
authors.lastname: Lopéz
authors.affiliation: Department of Biochemistry, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, 88040-900, Brazil.
authors.forename: Carla Ines
authors.initials: CI
authors.lastname: Tasca
authors.affiliation: Department of Biochemistry, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, 88040-900, Brazil.
authors.forename: Ana Lúcia Severo
authors.initials: ALS
authors.lastname: Rodrigues
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D005492:Folic Acid / Q000494:pharmacology*; D018698:Glutamic Acid / Q000494:pharmacology*; D000071679:Glycogen Synthase Kinase 3 beta / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D018696:Neuroprotective Agents; D018698:Glutamic Acid; D005492:Folic Acid; D052247:Nitric Oxide Synthase Type II; D019869:Phosphatidylinositol 3-Kinases; D000071679:Glycogen Synthase Kinase 3 beta
keywords: Folic acid; GSK-3β; Glutamate; Hippocampal slices; PI3K; iNOS; β-Catenin