Suppression and Epigenetic Regulation of MiR-9 Contributes to Ethanol Teratology: Evidence from Zebrafish and Murine Fetal Neural Stem Cell Models
- Authors
- Pappalardo-Carter, D.L., Balaraman, S., Sathyan, P., Carter, E.S., Chen, W.J., and Miranda, R.C.
- ID
- ZDB-PUB-130710-70
- Date
- 2013
- Source
- Alcoholism, clinical and experimental research 37(10): 1657-1667 (Journal)
- Registered Authors
- Keywords
- MiR-9, zebrafish, embryonic development, ethanol, methylation
- MeSH Terms
-
- Animals
- Epigenesis, Genetic/drug effects
- Epigenesis, Genetic/physiology*
- Ethanol/toxicity*
- Fetal Stem Cells/drug effects
- Fetal Stem Cells/physiology*
- Gene Knockdown Techniques/methods
- Mice
- Mice, Inbred C57BL
- MicroRNAs/physiology*
- Neural Stem Cells/drug effects
- Neural Stem Cells/physiology*
- Random Allocation
- Teratogenesis/drug effects
- Teratogenesis/physiology*
- Zebrafish
- PubMed
- 23800254 Full text @ Alcoholism Clin. Exp. Res.
Background
Fetal alcohol exposure produces multiorgan defects, making it difficult to identify underlying etiological mechanisms. However, recent evidence for ethanol (EtOH) sensitivity of the miRNA miR-9 suggests one mechanism, whereby EtOH broadly influences development. We hypothesized that loss of miR-9 function recapitulates aspects of EtOH teratology.
Methods
Zebrafish embryos were exposed to EtOH during gastrulation, or injected with anti-miR-9 or nonsense control morpholinos during the 2-cell stage of development and collected between 24 and 72 hours postfertilization (hpf). We also assessed the expression of developmentally important, and known miR-9 targets, FGFR-1, FOXP2, and the nontargeted transcript, MECP2. Methylation at CpG islands of mammalian miR-9 genes was assessed in fetal murine neural stem cells (mNSCs) by methylation-specific PCR, and miRNA processing assessed by qRT-PCR for pre-miR-9 transcripts.
Results
EtOH treatment and miR-9 knockdown resulted in similar cranial defects including microcephaly. Additionally, EtOH transiently suppressed miR-9, as well as FGFR-1 and FOXP2, and alterations in miR-9 expression were correlated with severity of EtOH-induced teratology. In mNSCs, EtOH increased CpG dinucleotide methylation at the miR-9-2 locus and accumulation of pre-miR-9-3.
Conclusions
EtOH exerts regulatory control at multiple levels of miR-9 biogenesis. Moreover, early embryonic loss of miR-9 function recapitulated the severe range of teratology associated with developmental EtOH exposure. EtOH also disrupts the relationship between miR-9 and target gene expression, suggesting a nuanced relationship between EtOH and miRNA regulatory networks in the developing embryo. The implications of these data for the expression and function of mature miR-9 warrant further investigation.