title: Sustained behavioral effects of lithium exposure during early development in zebrafish: involvement of the Wnt-β-catenin signaling pathway.
abstract: Lithium has been the paradigmatic treatment for bipolar disorder since 1950s, offering prophylactic and acute efficacy against maniac and depressive episodes. Its use during early pregnancy and the perinatal period remains controversial due to reports of negative consequences on the newborn including teratogenic and neurobehavioral effects generally referred as Floppy baby syndrome. The mechanisms underlying lithium therapeutic action are still elusive but exacerbation of Wnt signaling pathway due to GSK-3 inhibition is believed to represent its main effect. In this study we evaluated the impact of lithium exposure during zebrafish embryonic and early development including behavioral and molecular characterization of Wnt-β-catenin pathway components. Wild-type zebrafish embryos were individually treated for 72 hpf with LiCl at 0.05, 0.5 and 5mM. No significant teratogenic and embryotoxic effects were observed. At the end of treatment period western blot analysis of selected Wnt-β-catenin system components showed increased β-catenin and decreased N-cadherin protein levels, without significant changes in Wnt3a, supporting GSK-3 inhibition as lithium's main target. At 10 dpf 0.5 and 5mM lithium-treated larvae showed a dose-dependent decrease in locomotion among other exploratory parameters, resembling lithium-induced Floppy baby syndrome neurobehavioral symptoms in humans. At this later period previously altered proteins returned to control levels in treated groups, suggesting that the neurobehavioral effects are a lasting consequence of lithium exposure during early development. RT-qPCR analysis of β-catenin and N-cadherin gene expression showed no effects of lithium at 3 or 10 dpf, suggesting that protein fluctuations were likely due to post-transcriptional events. Other Wnt target genes were evaluated and only discrete alterations were observed. These results suggest that zebrafish may be a valuable model for investigation of early effects of lithium that may be mediated by effects on the Wnt signaling pathway.
authors.affiliation: Laboratório de Biologia e Desenvolvimento do Sistema Nervoso, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande, 90619-900 Porto Alegre, RS, Brazil; ZebLab, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande, 90619-900 Porto Alegre, RS, Brazil.
authors.forename: Laura R
authors.initials: LR
authors.lastname: Nery
authors.affiliation: Laboratório de Biologia e Desenvolvimento do Sistema Nervoso, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande, 90619-900 Porto Alegre, RS, Brazil; ZebLab, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande, 90619-900 Porto Alegre, RS, Brazil.
authors.forename: Natália S
authors.initials: NS
authors.lastname: Eltz
authors.affiliation: Laboratório de Biologia e Desenvolvimento do Sistema Nervoso, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande, 90619-900 Porto Alegre, RS, Brazil; ZebLab, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande, 90619-900 Porto Alegre, RS, Brazil.
authors.forename: Lídia
authors.initials: L
authors.lastname: Martins
authors.affiliation: ZebLab, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande, 90619-900 Porto Alegre, RS, Brazil.
authors.forename: Laura D
authors.initials: LD
authors.lastname: Guerim
authors.affiliation: ZebLab, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande, 90619-900 Porto Alegre, RS, Brazil; Laboratório de Biologia Genômica e Molecular, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900 Porto Alegre, RS, Brazil.
authors.forename: Talita C
authors.initials: TC
authors.lastname: Pereira
authors.affiliation: ZebLab, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande, 90619-900 Porto Alegre, RS, Brazil; Laboratório de Biologia Genômica e Molecular, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900 Porto Alegre, RS, Brazil; National Institute for Translational Medicine (INCT-TM), 90035-003 Porto Alegre, RS, Brazil.
authors.forename: Maurício R
authors.initials: MR
authors.lastname: Bogo
authors.affiliation: Laboratório de Biologia e Desenvolvimento do Sistema Nervoso, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande, 90619-900 Porto Alegre, RS, Brazil; ZebLab, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande, 90619-900 Porto Alegre, RS, Brazil; National Institute for Translational Medicine (INCT-TM), 90035-003 Porto Alegre, RS, Brazil. Electronic address: monica.vianna@pucrs.br.
authors.forename: Monica R M
authors.initials: MR
authors.lastname: Vianna
mesh_terms: D000818:Animals; D018692:Antimanic Agents / Q000633:toxicity*; D015153:Blotting, Western; D015820:Cadherins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006330:Heart Defects, Congenital / Q000139:chemically induced; D053208:Kaplan-Meier Estimate; D018021:Lithium Chloride / Q000633:toxicity*; D009043:Motor Activity / Q000502:physiology; D012333:RNA, Messenger; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013623:Tail / Q000002:abnormalities; D060509:Wnt3A Protein / Q000378:metabolism*; D015027:Zebrafish / Q000254:growth & development* / Q000502:physiology; D029961:Zebrafish Proteins / Q000378:metabolism*; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D018692:Antimanic Agents; D015820:Cadherins; C513786:N-cadherin, zebrafish; D012333:RNA, Messenger; D060509:Wnt3A Protein; C555512:Wnt3a protein, zebrafish; D029961:Zebrafish Proteins; D051176:beta Catenin; D018021:Lithium Chloride
keywords: Lithium; N-Cadherin; Neurobehavioral effects; Wnt; Zebrafish; β-Catenin