title: Reversible reprotoxic effects of manganese through DAF-16 transcription factor activation and vitellogenin downregulation in Caenorhabditis elegans.
abstract: OBJECTIVE
  Vitellogenesis is the yolk production process which provides the essential nutrients for the developing embryos. Yolk is a lipoprotein particle that presents lipids and lipid-binding proteins, referred to as vitellogenins (VIT). The Caenorhabditis elegans nematode has six genes encoding VIT lipoproteins. Several pathways are known to regulate vitellogenesis, including the DAF-16 transcription factor. Some reports have shown that heavy metals, such as manganese (Mn), impair brood size in C. elegans; however the mechanisms associated with this effect have yet to be identified. Our aim was to evaluate Mn's effects on C. elegans reproduction and better understand the pathways related to these effects.
  
  
  METHODS
  Young adult larval stage worms were treated for 4h with Mn in 85mM NaCl and Escherichia coli OP50 medium.
  
  
  RESULTS
  Mn reduced egg-production and egg-laying during the first 24h after the treatment, although the total number of progenies were indistinguishable from the control group levels. This delay may have occurred due to DAF-16 activation, which was noted only after the treatment and was not apparent 24h later. Moreover, the expression, protein levels and green fluorescent protein (GFP) fluorescence associated with VIT were decreased soon after Mn treatment and recovered after 24h.
  
  
  CONCLUSIONS
  Combined, these data suggest that the delay in egg-production is likely regulated by DAF-16 and followed by the inhibition of VIT transport activity. Further studies are needed to clarify the mechanisms associated with Mn-induced DAF-16 activation.
authors.affiliation: Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
authors.forename: Priscila
authors.initials: P
authors.lastname: Gubert
authors.affiliation: Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
authors.forename: Bruna
authors.initials: B
authors.lastname: Puntel
authors.affiliation: Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
authors.forename: Tassia
authors.initials: T
authors.lastname: Lehmen
authors.affiliation: Institute of Nutritional Sciences, University of Potsdam, Arthur-Scheunert-Allee 114-166, 14558 Nuthetal, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Bornhorst
authors.affiliation: Laboratório do Grupo de Pesquisa em Bioquímica e Toxicologia em Caenorhabditis elegans (GBToxCe), Universidade Federal do Pampa - UNIPAMPA, Uruguaiana, RS, Brazil.
authors.forename: Daiana S
authors.initials: DS
authors.lastname: Avila
authors.affiliation: Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Aschner
authors.affiliation: Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil. Electronic address: felix@ufsm.br.
authors.forename: Felix A A
authors.initials: FAA
authors.lastname: Soares
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D015536:Down-Regulation / Q000187:drug effects*; D051858:Forkhead Transcription Factors / Q000378:metabolism*; D008345:Manganese / Q000633:toxicity*; D010063:Ovum / Q000187:drug effects; D014819:Vitellogenins / Q000172:deficiency / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; D051858:Forkhead Transcription Factors; D014819:Vitellogenins; C108831:daf-16 protein, C elegans; D008345:Manganese
keywords: Brood size; Caenorhabditis elegans; DAF-16 transcription factor; Manganese; Vitellogenin