title: Mechanisms of manganese-induced neurotoxicity in primary neuronal cultures: the role of manganese speciation and cell type.
abstract: Manganese (Mn) is an essential trace element required for the proper functioning of a variety of physiological processes. However, chronic exposures to Mn can cause neurotoxicity in humans, especially when it occurs during critical stages of the central nervous system development. The mechanisms mediating this phenomenon as well as the contribution of Mn speciation and the sensitivity of different types of neuronal cells in such toxicity are poorly understood. This study was aimed to investigate the mechanisms mediating the toxic effects of MnCl(2), Mn(II) citrate, Mn(III) citrate, and Mn(III) pyrophosphate in primary cultures of neocortical (CTX) and cerebellar granular (CGC) neurons. Cell viability, mitochondrial function, and glutathione levels were evaluated after Mn exposure. CGC were significantly more susceptible to Mn-induced toxicity when compared with CTX. Moreover, undifferentiated CGC were more vulnerable to Mn toxicity than mature neurons. Mitochondrial dysfunction was observed after the exposure to all the tested Mn species. Ascorbate protected CGC against Mn-induced neurotoxicity, and this event seemed to be related to the dual role of ascorbate in neurons, acting as antioxidant and metabolic energetic supplier. CTX were protected from Mn-induced toxicity by ascorbate only when coincubated with lactate. These findings reinforce and extend the notion of the hazardous effects of Mn toward neuronal cells. In addition, the present results indicate that Mn-induced neurotoxicity is influenced by brain cell types, their origins, and developmental stages as well as by the chemical speciation of Mn, thus providing important information about Mn-induced developmental neurotoxicity and its risk assessment.
authors.affiliation: Department of Neurochemistry and Neuropharmacology, Institut d'Investigacions Biomèdiques de Barcelona, IIBB-CSIC-IDIBAPS, Barcelona 08036, Spain.
authors.forename: R B
authors.initials: RB
authors.lastname: Hernández
authors.forename: M
authors.initials: M
authors.lastname: Farina
authors.forename: B P
authors.initials: BP
authors.lastname: Espósito
authors.forename: N C
authors.initials: NC
authors.lastname: Souza-Pinto
authors.forename: F
authors.initials: F
authors.lastname: Barbosa
authors.forename: C
authors.initials: C
authors.lastname: Suñol
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001205:Ascorbic Acid / Q000494:pharmacology; D018929:Cell Culture Techniques; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000187:drug effects* / Q000196:embryology / Q000254:growth & development / Q000473:pathology; D002540:Cerebral Cortex / Q000187:drug effects* / Q000196:embryology / Q000254:growth & development / Q000473:pathology; D004578:Electron Spin Resonance Spectroscopy; D005978:Glutathione / Q000378:metabolism; D008345:Manganese / Q000737:chemistry / Q000493:pharmacokinetics / Q000633:toxicity*; D017895:Manganese Compounds / Q000737:chemistry / Q000493:pharmacokinetics; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008815:Mice, Inbred Strains; D008928:Mitochondria / Q000187:drug effects; D009474:Neurons / Q000187:drug effects*; D020258:Neurotoxicity Syndromes / Q000209:etiology / Q000517:prevention & control; D038081:Organogenesis / Q000187:drug effects; D009942:Organometallic Compounds / Q000737:chemistry / Q000493:pharmacokinetics / Q000633:toxicity; D010084:Oxidation-Reduction; D013054:Spectrophotometry, Atomic; D013056:Spectrophotometry, Ultraviolet
chemical_list: D017895:Manganese Compounds; D009942:Organometallic Compounds; D008345:Manganese; D005978:Glutathione; D001205:Ascorbic Acid