title: Lectin from Canavalia brasiliensis (ConBr) protects hippocampal slices against glutamate neurotoxicity in a manner dependent of PI3K/Akt pathway.
abstract: The excitotoxicity induced by excessive activation of the glutamatergic neurotransmission pathway is involved in several neuropathologies. In this sense, molecules that prevent the release of glutamate or the excessive activation of its receptors can be useful in preventing the neuronal cell death observed in these diseases. Lectins are proteins capable of reversible binding to the carbohydrates in glycoconjugates, and some have been used in the study and purification of glutamate receptors. ConBr is a mannose/glucose-binding lectin purified from Canavalia brasiliensis seeds. In the present study, we aimed to evaluate the neuroprotective activity of ConBr against glutamate-induced excitotoxicity. Hippocampal slices were isolated from adult male mice and incubated for 6h in Krebs saline/DMEM buffer alone (control), in the presence of glutamate or glutamate plus ConBr. The phosphorylation of Akt and mitogen activated protein kinases (MAPKs) such as ERK1/2, p38(MAPK) and JNK1/2/3 was evaluated with western blotting. The results indicate that glutamate provoked a reduction in the hippocampal slice viability (-25%), diminished the phosphorylation of Akt and augmented p38(MAPK) and ERK1 phosphorylation. No changes were observed in the phosphorylation of JNK1/2/3 or ERK2. Notably, ConBr, through a mechanism dependent on carbohydrate interaction, prevented the reduction of cell viability and Akt phosphorylation induced by glutamate. Furthermore, in the presence of the PI3K inhibitor LY294002, ConBr was unable to reverse glutamate neurotoxicity. Taken together, our data suggest that the neuroprotective effect of ConBr against glutamate neurotoxicity requires oligosaccharide interaction and is dependent on the PI3K/Akt pathway.
authors: Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, SC, Brazil.
authors: Amanda V
authors: AV
authors: Jacques
authors: Débora K
authors: DK
authors: Rieger
authors: Mariana
authors: M
authors: Maestri
authors: Mark W
authors: MW
authors: Lopes
authors: Tanara V
authors: TV
authors: Peres
authors: Filipe M
authors: FM
authors: Gonçalves
authors: Daniela Z
authors: DZ
authors: Pedro
authors: Carla I
authors: CI
authors: Tasca
authors: Manuela G
authors: MG
authors: López
authors: Javier
authors: J
authors: Egea
authors: Kyria S
authors: KS
authors: Nascimento
authors: Benildo S
authors: BS
authors: Cavada
authors: Rodrigo B
authors: RB
authors: Leal
mesh_terms: D000818:Animals; D015153:Blotting, Western; D032449:Canavalia / Q000737:chemistry*; D050260:Carbohydrate Metabolism / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists; D018698:Glutamic Acid / Q000633:toxicity*; D006624:Hippocampus / Q000187:drug effects* / Q000473:pathology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology; D009025:Morpholines / Q000494:pharmacology; D018696:Neuroprotective Agents; D051058:Oncogene Protein v-akt / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D010766:Phosphorylation; D037121:Plant Lectins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects*; D013778:Tetrazolium Salts; D013844:Thiazoles
chemical_list: D002867:Chromones; D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; D009025:Morpholines; D018696:Neuroprotective Agents; D037121:Plant Lectins; D013778:Tetrazolium Salts; D013844:Thiazoles; C039268:lectin, Canavalia; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D018698:Glutamic Acid; D019869:Phosphatidylinositol 3-Kinases; D051058:Oncogene Protein v-akt; D020928:Mitogen-Activated Protein Kinases; C022616:thiazolyl blue