title: Ethanol-induced upregulation of 10-formyltetrahydrofolate dehydrogenase helps relieve ethanol-induced oxidative stress.
abstract: Alcoholism induces folate deficiency and increases the risk for embryonic anomalies. However, the interplay between ethanol exposure and embryonic folate status remains unclear. To investigate how ethanol exposure affects embryonic folate status and one-carbon homeostasis, we incubated zebrafish embryos in ethanol and analyzed embryonic folate content and folate enzyme expression. Exposure to 2% ethanol did not change embryonic total folate content but increased the tetrahydrofolate level approximately 1.5-fold. The expression of 10-formyltetrahydrofolate dehydrogenase (FDH), a potential intracellular tetrahydrofolate reservoir, was increased in both mRNA and protein levels. Overexpressing recombinant FDH in embryos alleviated the ethanol-induced oxidative stress in ethanol-exposed embryos. Further characterization of the zebrafish fdh promoter revealed that the -124/+40 promoter fragment was the minimal region required for transactivational activity. The results of site-directed mutagenesis and binding analysis revealed that Sp1 is involved in the basal level of expression of fdh but not in ethanol-induced upregulation of fdh. On the other hand, CEBPα was the protein that mediated the ethanol-induced upregulation of fdh, with an approximately 40-fold increase of fdh promoter activity when overexpressed in vitro. We concluded that upregulation of fdh involving CEBPα helps relieve embryonic oxidative stress induced by ethanol exposure.
authors.affiliation: Institute of Basic Medical Science, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Tsun-Hsien
authors.initials: TH
authors.lastname: Hsiao
authors.forename: Chia-Jen
authors.initials: CJ
authors.lastname: Lin
authors.forename: Yi-Shao
authors.initials: YS
authors.lastname: Chung
authors.forename: Gang-Hui
authors.initials: GH
authors.lastname: Lee
authors.forename: Tseng-Ting
authors.initials: TT
authors.lastname: Kao
authors.forename: Wen-Ni
authors.initials: WN
authors.lastname: Chang
authors.forename: Bing-Hung
authors.initials: BH
authors.lastname: Chen
authors.forename: Jan-Jong
authors.initials: JJ
authors.lastname: Hung
authors.forename: Tzu-Fun
authors.initials: TF
authors.lastname: Fu
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics / Q000378:metabolism; D002492:Central Nervous System Depressants / Q000494:pharmacology; D004625:Embryo, Nonmammalian / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D000431:Ethanol / Q000494:pharmacology*; D005492:Folic Acid / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D018384:Oxidative Stress / Q000187:drug effects*; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D013763:Tetrahydrofolates / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects*; D015027:Zebrafish / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*; D000099295:Formyltetrahydrofolate Dehydrogenase
chemical_list: D022763:CCAAT-Enhancer-Binding Protein-alpha; D002492:Central Nervous System Depressants; D000431:Ethanol; D005492:Folic Acid; D000587:Oxidoreductases Acting on CH-NH Group Donors; D013763:Tetrahydrofolates; D029961:Zebrafish Proteins; D000099295:Formyltetrahydrofolate Dehydrogenase; C030371:5,6,7,8-tetrahydrofolic acid