The transcription factor c-Myc suppresses MiR-23b and MiR-27b transcription during fetal distress and increases the sensitivity of neurons to hypoxia-induced apoptosis

PLoS One. 2015 Mar 17;10(3):e0120217. doi: 10.1371/journal.pone.0120217. eCollection 2015.

Abstract

Previous studies reported that the expression of miR-23b-27b cluster was downregulated in embryonic brain cortices during hypoxia-induced neuronal apoptosis. However, the mechanism underlying this downregulation is not completely understood. Here, we report that the transcription factor c-Myc plays an important role in regulating the expression of miR-23b-27b cluster during hypoxia. First, the c-Myc protein level was significantly elevated in embryonic brain cortices in a mouse model of fetal distress. Second, forced overexpression or knockdown of c-Myc could suppress or increase the expression of miR-23b-27b cluster polynucleotides. Third, we identified 2 conserved c-Myc binding sites (E-boxes) in the enhancer and promoter regions of miR-23b-27b cluster in the mouse genome. Finally, we showed that elevated c-Myc expression led to an increase in the Apaf-1 level by suppressing miR-23b-27b cluster expression and that this enhanced neuronal sensitivity to apoptosis. In summary, our study demonstrates that c-Myc may suppress the expression of the miR-23b-27b cluster, resulting in additional neuronal apoptosis during hypoxia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis*
  • Cell Hypoxia
  • Mice
  • MicroRNAs / biosynthesis*
  • Neurons / metabolism*
  • Proto-Oncogene Proteins c-myc / metabolism*
  • Response Elements
  • Transcription, Genetic*

Substances

  • MicroRNAs
  • Mirn23b microRNA, mouse
  • Mirn27 microRNA, mouse
  • Myc protein, mouse
  • Proto-Oncogene Proteins c-myc

Grants and funding

This work was supported by grants from the National Natural Science Foundation of China (31100777, 30988003 and 90608010) and the Natural Science Foundation of Jiangsu Province (BK2011013). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.