Zhang Chengjin, Anderson Ashley, Cole Gregory J
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.
Birth Defects Res A Clin Mol Teratol. 2015 Dec;103(12):1046-57. doi: 10.1002/bdra.23460. Epub 2015 Oct 16.
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.
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.
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.
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.
乙醇是一种致畸剂，会影响发育中的神经系统的多个区域。本研究旨在确定乙醇是独立破坏不同的信号通路，还是破坏调节乙醇敏感组织发育的相互作用通路。
将斑马鱼胚胎暴露于乙醇中，同时存在或不存在醛脱氢酶1a3（aldh1a3）或音猬因子（Shh）吗啉代寡核苷酸（MOs），它们分别破坏视黄酸（RA）或音猬因子（Shh）的功能。对眼睛或中脑-后脑边界（MHB）的发育进行形态学分析，并评估挽救乙醇和MO诱导的表型的能力。原位杂交用于分析眼睛发育过程中Pax6a的表达。
慢性乙醇暴露，或乙醇与MO联合处理，会导致MHB形成紊乱和小眼症。虽然RA可以挽救乙醇与任何一种MO联合处理后的MHB表型，但Shh mRNA无法挽救乙醇与aldh1a3 MO联合处理导致的MHB破坏。RA也无法挽救乙醇和Shh MO诱导的小眼症。
这些研究表明，虽然RA或Shh信号的减少会导致相同的MHB或眼睛发育破坏，这可以用乙醇与任何一种MO联合处理来模拟，但在亚阈值Shh MO和乙醇联合处理中，RA过表达只能挽救破坏的MHB，而不能挽救小眼症。我们的数据表明，MHB的发育可能涉及RA和Shh信号之间的相互作用，而眼睛发育依赖于RA和Shh信号传导，这两者都是胎儿酒精谱系障碍中乙醇的作用靶点，但不依赖于涉及相互作用的机制。
