title: How mitochondrial dysfunction affects zebrafish development and cardiovascular function: an in vivo model for testing mitochondria-targeted drugs.
abstract: OBJECTIVE
  Mitochondria are a drug target in mitochondrial dysfunction diseases and in antiparasitic chemotherapy. While zebrafish is increasingly used as a biomedical model, its potential for mitochondrial research remains relatively unexplored. Here, we perform the first systematic analysis of how mitochondrial respiratory chain inhibitors affect zebrafish development and cardiovascular function, and assess multiple quinones, including ubiquinone mimetics idebenone and decylubiquinone, and the antimalarial atovaquone.
  
  
  METHODS
  Zebrafish (Danio rerio) embryos were chronically and acutely exposed to mitochondrial inhibitors and quinone analogues. Concentration-response curves, developmental and cardiovascular phenotyping were performed together with sequence analysis of inhibitor-binding mitochondrial subunits in zebrafish versus mouse, human and parasites. Phenotype rescuing was assessed in co-exposure assays.
  
  
  RESULTS
  Complex I and II inhibitors induced developmental abnormalities, but their submaximal toxicity was not additive, suggesting active alternative pathways for complex III feeding. Complex III inhibitors evoked a direct normal-to-dead transition. ATP synthase inhibition arrested gastrulation. Menadione induced hypochromic anaemia when transiently present following primitive erythropoiesis. Atovaquone was over 1000-fold less lethal in zebrafish than reported for Plasmodium falciparum, and its toxicity partly rescued by the ubiquinone precursor 4-hydroxybenzoate. Idebenone and decylubiquinone delayed rotenone- but not myxothiazol- or antimycin-evoked cardiac dysfunction.
  
  
  CONCLUSIONS
  This study characterizes pharmacologically induced mitochondrial dysfunction phenotypes in zebrafish, laying the foundation for comparison with future studies addressing mitochondrial dysfunction in this model organism. It has relevant implications for interpreting zebrafish disease models linked to complex I/II inhibition. Further, it evidences zebrafish's potential for in vivo efficacy or toxicity screening of ubiquinone analogues or antiparasitic mitochondria-targeted drugs.
authors.affiliation: REQUIMTE, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, Porto, Portugal.
authors.forename: Brígida R
authors.initials: BR
authors.lastname: Pinho
authors.forename: Miguel M
authors.initials: MM
authors.lastname: Santos
authors.forename: Anabela
authors.initials: A
authors.lastname: Fonseca-Silva
authors.forename: Patrícia
authors.initials: P
authors.lastname: Valentão
authors.forename: Paula B
authors.initials: PB
authors.lastname: Andrade
authors.forename: Jorge M A
authors.initials: JM
authors.lastname: Oliveira
mesh_terms: D000818:Animals; D000977:Antiparasitic Agents / Q000494:pharmacology*; D004625:Embryo, Nonmammalian / Q000187:drug effects; D047108:Embryonic Development / Q000187:drug effects; D006321:Heart / Q000187:drug effects / Q000196:embryology / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000502:physiology; D011809:Quinones / Q000494:pharmacology*; D015027:Zebrafish / Q000196:embryology*
chemical_list: D000977:Antiparasitic Agents; D011809:Quinones