Project description:Gene expression was measured using microarrays in 8 hour postfertilization embryos, comparing control versus ethanol-treated (2 to 8 hours postfertilization) embryos. This experiment was performed to determine the gene expression changes that occur in response to ethanol treatment as a model of fetal alcohol spectrum disorder. Fetal alcohol spectrum disorder (FASD) occurs when pregnant mothers consume alcohol, causing embryonic ethanol exposure and characteristic birth defects that include craniofacial, neural and cardiac defects. Gastrulation is a particularly sensitive developmental stage for teratogen exposure, and zebrafish is an outstanding model to study gastrulation and FASD. Epiboly (spreading blastomere cells over the yolk cell), prechordal plate migration and convergence/extension cell movements are sensitive to early ethanol exposure. Here, experiments are presented to characterize mechanisms of ethanol toxicity on epiboly and gastrulation. Epiboly mechanisms include blastomere radial intercalation cell movements and yolk cell microtubule cytoskeleton pulling the embryo to the vegetal pole. Both of these processes were disrupted by ethanol exposure. Ethanol effects on cell migration also indicated that cell adhesion was affected, which was confirmed by cell aggregation assays. E-cadherin cell adhesion molecule expression and distribution, which control epiboly and gastrulation, were not affected. Gene expression microarray analysis was used to identify potential causative factors for early development defects, and expression of the cell adhesion molecule protocadherin-18a (pcdh18a), which controls epiboly, was significantly reduced in ethanol-exposed embryos. Injecting pcdh18a synthetic mRNA in ethanol-treated embryos partially rescued epiboly cell movements, including enveloping layer cell shape changes. Together, data show that epiboly and gastrulation defects induced by ethanol are multifactorial, and include yolk cell (extraembryonic tissue) microtubule cytoskeleton disruption and blastomere adhesion defects, in part caused by reduced pcdh18a expression. Control vs. ethanol-treated zebrafish embryos that were treated from 2 to 8 hours postfertilization. Total RNA from control and ethanol-treated embryos were harvested at 8 hours postfertilization.

Project description:Alcohol exposure during the formation and closure of the neural tube, or neurulation (embryonic day [E] 8-10 in mice; ∼4th week of human pregnancy), perturbs development of midline brain structures and significantly disrupts gene expression in the rostroventral neural tube (RVNT). Previously, alcohol exposure during neurulation was found to alter gene pathways related to cell proliferation, p53 signaling, ribosome biogenesis, immune signaling, organogenesis, and cell migration 6 or 24 hours after administration. Our current study expands upon this work by investigating short-term gene expression changes in the RVNT following a single binge-like alcohol exposure during neurulation. Female C57BL/6J mice were administered a single dose of 2.9 g/kg alcohol or vehicle on E9.0 to target mid-neurulation. The RVNTs of stage-matched embryos were collected 2 or 4 hours after exposure and processed for RNA-seq. Functional profiling was performed with g:Profiler, as well as the CiliaCarta and DisGeNet databases. Two hours following E9.0 alcohol exposure, 650 genes in the RVNT were differentially expressed. Functional enrichment analysis revealed that pathways related to cellular metabolism, gene expression, cell cycle, organogenesis, and Hedgehog signaling were down-regulated and pathways related to cellular stress response, p53 signaling, and hypoxia were up-regulated by alcohol. Four hours after alcohol, 225 genes were differentially expressed. Biological processes related to metabolism, RNA binding, ribosome biogenesis, and methylation were down-regulated, while protein localization and binding, autophagy, and intracellular signaling pathways were up-regulated. Two hr after alcohol, the differentially expressed genes were associated with disease terms related to eye and craniofacial development and anoxia. These data provide further information regarding the biological functions targeted by alcohol exposure during neurulation in regions of the neural tube that give rise to alcohol-sensitive midline brain structures. Disruption of these gene pathways contributes to the craniofacial and brain malformations associated with prenatal alcohol exposure.

Project description:Gene expression was measured using microarrays in 8 hour postfertilization embryos, comparing control versus ethanol-treated (2 to 8 hours postfertilization) embryos. This experiment was performed to determine the gene expression changes that occur in response to ethanol treatment as a model of fetal alcohol spectrum disorder. Fetal alcohol spectrum disorder (FASD) occurs when pregnant mothers consume alcohol, causing embryonic ethanol exposure and characteristic birth defects that include craniofacial, neural and cardiac defects. Gastrulation is a particularly sensitive developmental stage for teratogen exposure, and zebrafish is an outstanding model to study gastrulation and FASD. Epiboly (spreading blastomere cells over the yolk cell), prechordal plate migration and convergence/extension cell movements are sensitive to early ethanol exposure. Here, experiments are presented to characterize mechanisms of ethanol toxicity on epiboly and gastrulation. Epiboly mechanisms include blastomere radial intercalation cell movements and yolk cell microtubule cytoskeleton pulling the embryo to the vegetal pole. Both of these processes were disrupted by ethanol exposure. Ethanol effects on cell migration also indicated that cell adhesion was affected, which was confirmed by cell aggregation assays. E-cadherin cell adhesion molecule expression and distribution, which control epiboly and gastrulation, were not affected. Gene expression microarray analysis was used to identify potential causative factors for early development defects, and expression of the cell adhesion molecule protocadherin-18a (pcdh18a), which controls epiboly, was significantly reduced in ethanol-exposed embryos. Injecting pcdh18a synthetic mRNA in ethanol-treated embryos partially rescued epiboly cell movements, including enveloping layer cell shape changes. Together, data show that epiboly and gastrulation defects induced by ethanol are multifactorial, and include yolk cell (extraembryonic tissue) microtubule cytoskeleton disruption and blastomere adhesion defects, in part caused by reduced pcdh18a expression.

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Transcriptomic analyses of gastrulation-stage C57BL/6J and C57BL/6NHsd mouse embryos with differential susceptibility to alcohol

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