title: Quinolinic acid induces disrupts cytoskeletal homeostasis in striatal neurons. Protective role of astrocyte-neuron interaction.
abstract: Quinolinic acid (QUIN) is an endogenous metabolite of the kynurenine pathway involved in several neurological disorders. Among the several mechanisms involved in QUIN-mediated toxicity, disruption of the cytoskeleton has been demonstrated in striatally injected rats and in striatal slices. The present work searched for the actions of QUIN in primary striatal neurons. Neurons exposed to 10 µM QUIN presented hyperphosphorylated neurofilament (NF) subunits (NFL, NFM, and NFH). Hyperphosphorylation was abrogated in the presence of protein kinase A and protein kinase C inhibitors H89 (20 μM) and staurosporine (10 nM), respectively, as well as by specific antagonists to N-methyl-D-aspartate (50 µM DL-AP5) and metabotropic glutamate receptor 1 (100 µM MPEP). Also, intra- and extracellular Ca(2+) chelators (10 µM BAPTA-AM and 1 mM EGTA, respectively) and Ca(2+) influx through L-type voltage-dependent Ca(2+) channel (10 µM verapamil) are implicated in QUIN-mediated effects. Cells immunostained for the neuronal markers βIII-tubulin and microtubule-associated protein 2 showed altered neurite/neuron ratios and neurite outgrowth. NF hyperphosphorylation and morphological alterations were totally prevented by conditioned medium from QUIN-treated astrocytes. Cocultured astrocytes and neurons interacted with one another reciprocally, protecting them against QUIN injury. Cocultured cells preserved their cytoskeletal organization and cell morphology together with unaltered activity of the phosphorylating system associated with the cytoskeleton. This article describes cytoskeletal disruption as one of the most relevant actions of QUIN toxicity in striatal neurons in culture with soluble factors secreted by astrocytes, with neuron-astrocyte interaction playing a role in neuroprotection.
authors.affiliation: Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Paula
authors.initials: P
authors.lastname: Pierozan
authors.forename: Fernanda
authors.initials: F
authors.lastname: Ferreira
authors.forename: Bárbara Ortiz
authors.initials: BO
authors.lastname: de Lima
authors.forename: Regina
authors.initials: R
authors.lastname: Pessoa-Pureur
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000737:chemistry / Q000502:physiology*; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D018920:Coculture Techniques; D003342:Corpus Striatum / Q000166:cytology*; D017077:Culture Media, Conditioned / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005260:Female; D006706:Homeostasis / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects*; D010766:Phosphorylation / Q000187:drug effects; D011247:Pregnancy; D017378:Quinolinic Acid / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D002614:Chelating Agents; D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D004533:Egtazic Acid; C056639:2-amino-5-phosphopentanoic acid; D017378:Quinolinic Acid; D014633:Valine
keywords: astrocyte-conditioned medium; astrocyte-neuron interaction; neurite outgrowth; neurofilament; neuronal cytoskeleton; quinolinic acid