Browsing by Subject "fetal alcohol spectrum disorder (FASD)"

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    Fetal Alcohol Syndrome Affects in Retinal Cell Gene Expression
    (Office of the Vice Chancellor for Research, 2015-04-17) Rodriguez, Joseph; Kubicek, Christin
    Alcohol exposure during fetal development has many adverse effects on embryonic cells, this is known as fetal alcohol spectrum disorder (FASD). Retinal cells are consistently affected by ethanol exposure in human patients. Zebrafish are an excellent model to use for studying FASD on, due to their similar developmental pathways to humans. This research aims to understand the changes that occur at the gene level to retinal cells during exposure to ethanol. To better understand changes that occur in retinal cells, a project was begun to examine GFP marked Zebrafish embryos exposed to ethanol [100, 150 mM EtOH], from 2-24 hours postfertilization (hpf), and eyes from treated and control zebrafish embryos will be harvested using dissection, dissociated using papain protease digestion, sorted using fluorescence activated cell sorting (FACS). These GFP labeled cells can then be used to isolate retinal cell RNA for gene expression analysis. This research will provide insight into gene expression changes during retinal development is specific cell types after alcohol exposure. Our goal is to understand the genesis of FASD birth defects caused by ethanol exposure, and this research will possibly identify methods to prevent or reverse the damage.
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    Fetal Alcohol Syndrome Affects in Retinal Cell Gene Expression
    (Office of the Vice Chancellor for Research, 2016-04-08) Rodriguez, Joseph; Kaur, Navneet
    Alcohol exposure during fetal development has many adverse effects, producing birth defects known as fetal alcohol spectrum disorder (FASD). Retinal development is consistently affected by ethanol exposure in human patients. Zebrafish are an excellent model to study FASD, due to their similar developmental pathways to humans. Previous studies show that ethanol exposure caused retinal cell differentiation defects leading to photoreceptor defects similar to those seen in human FASD patients. This research aims to understand the gene expression changes that occur in retinal cells due to ethanol exposure. Zebrafish embryos exposed to ethanol [100, 150 mM], from 2-24 hours post-fertilization (hpf), were grown in regular medium until 72 hpf. Eyes from ethanol treated and control zebrafish embryos were dissected and total RNA was isolated. The RNA was then purified and reverse transcribed into cDNA. Quantitative PCR was then used to analyze the cDNA using gene specific primers to determine relative expression levels of various genes present in the retinal developmental pathway. We examined specific signaling pathways including, Wnt, Notch, pro-neural gene targets, and other specific markers expressed by retinal precursor cell populations that comprise the differentiation pathways. This research provides insight into gene expression changes during retinal development that affects specific cell types after alcohol exposure. Our goal is to understand the genesis of FASD birth defects caused by ethanol exposure, and this research will possibly identify ethanol targets and therapeutic strategies to prevent or reverse the damage.
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    Zebrafish retinal stem cell differentiation mechanisms are disrupted by embryonic ethanol exposure
    (Office of the Vice Chancellor for Research, 2016-04-08) Muralidharan, Pooja; Sarmah, Swapnalee; Marrs, James A.
    Prenatal alcohol exposure can lead to a wide range of developmental abnormalities, which are included under the umbrella term fetal alcohol spectrum disorder (FASD). To understand the genesis of FASD defects, the zebrafish is important mechanistic animal model, particularly for retinal development. Previous work from our laboratory showed that ethanol treatment during gastrulation through somitogenesis in zebrafish embryos could recapitulate human ocular defects including microphthalmia, optic nerve hypoplasia, and photoreceptor defects. Ethanol-treated embryos showed increased retinal proliferation in the outer nuclear layer (ONL), inner nuclear layer (INL), and ciliary marginal zone (CMZ). Retinoic acid (RA) and folic acid (FA) co-supplementation rescued most ethanol-induced retinal defects, suggesting that nutrient deficiencies contribute to FASD. To better understand the genesis of ethanol-induced retinal cell differentiation defects, effects of ethanol exposure on retinal stem cell populations in the CMZ and Müller glial cell populations were examined. Ethanol treated retinas had an expanded CMZ, and a reduced expression domain for the cell cycle exit marker, cdkn1c. Ethanol treated retinas also showed reduced GFAP-positive Müller glial cells, which are a stem cell population in the central retina. At 72 hpf, the ONL of ethanol exposed fish showed few photoreceptors expressing terminal differentiation markers. Importantly, these poorly differentiated photoreceptors co-expressed the bHLH differentiation factor, neuroD, indicating that ethanol exposure produced immature and undifferentiated photoreceptors. Reduced differentiation along with increased progenitor marker expression and proliferation suggest cell cycle exit disruption due to ethanol exposure. Ethanol exposure severely disrupted Wnt and Notch signaling, which are critical for stem cell behavior and differentiation. These defects were rescued by Wnt signaling agonist, RA, and FA treatments. These results suggest ethanol disrupted retinal cell differentiation mechanisms. Further analysis of underlying molecular mechanisms will provide insight into the ethanol-induced retinal defects and potential therapeutic targets.