title: Analysis of crosstalk between retinoic acid and sonic hedgehog pathways following ethanol exposure in embryonic zebrafish.
abstract: BACKGROUND
  Ethanol is a teratogen affecting numerous regions of the developing nervous system. The present study was undertaken to ascertain whether ethanol independently disrupts distinct signaling pathways or rather disrupts interactive pathways that regulate development of ethanol-sensitive tissues.
  
  
  METHODS
  Zebrafish embryos were exposed to ethanol in the absence or presence of aldh1a3 or Shh morpholino oligonucleotides (MOs), which disrupt retinoic acid (RA) or sonic hedgehog (Shh) function, respectively. Morphological analysis of ocular or midbrain-hindbrain boundary (MHB) development was conducted, and the ability to rescue ethanol and MO-induced phenotypes was assessed. In situ hybridization was used to analyze Pax6a expression during ocular development.
  
  
  RESULTS
  Chronic ethanol exposure, or combined ethanol and MO treatment, results in perturbed MHB formation and microphthalmia. While RA can rescue the MHB phenotype following ethanol combined with either MO, Shh mRNA is unable to rescue the disrupted MHB with combined ethanol and aldh1a3 MO treatment. RA also is unable to rescue microphthalmia induced by ethanol and Shh MO.
  
  
  CONCLUSIONS
  These studies demonstrate that while reduction of either RA or Shh signaling produces the same disruption of MHB or ocular development, that can be phenocopied using ethanol combined with either MO, RA overexpression can only rescue disrupted MHB, but not microphthalmia, in combined subthreshold Shh MO and ethanol. Our data suggest that MHB development may involve crosstalk between RA and Shh signaling, while ocular development depends on RA and Shh signaling that both are targets of ethanol in fetal alcohol spectrum disorders but do not depend on a mechanism involving crosstalk.
authors.affiliation: Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina, USA.
authors.forename: Chengjin
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Biological and Biomedical Sciences, North Carolina Central University, Durham, North Carolina, USA.
authors.forename: Ashley
authors.initials: A
authors.lastname: Anderson
authors.affiliation: Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina, USA.|Department of Biological and Biomedical Sciences, North Carolina Central University, Durham, North Carolina, USA.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Cole
mesh_terms: D000818:Animals; D001921:Brain / Q000196:embryology; D000431:Ethanol / Q000633:toxicity*; D005123:Eye / Q000196:embryology; D005136:Eye Proteins / Q000235:genetics; D053823:Hedgehog Proteins / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000235:genetics; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D014212:Tretinoin / Q000378:metabolism*; D015027:Zebrafish / Q000196:embryology*; D029961:Zebrafish Proteins / Q000378:metabolism*
chemical_list: D005136:Eye Proteins; D053823:Hedgehog Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins; C524053:Shha protein, zebrafish; D029961:Zebrafish Proteins; D000431:Ethanol; D014212:Tretinoin
keywords: FASD; microphthalmia; retinoic acid; sonic hedgehog; zebrafish