G9a-mediated histone methylation regulates ethanol-induced neurodegeneration in the neonatal mouse brain

Shivakumar Subbanna, Madhu Shivakumar, Nagavedi S. Umapathy, Mariko Saito, Panaiyur S. Mohan, Asok Kumar, Ralph A. Nixon, Alexander D. Verin, Delphine Psychoyos, Balapal S. Basavarajappa

Research output: Contribution to journalArticle

60 Scopus citations

Abstract

Rodent exposure to binge-like ethanol during postnatal day 7 (P7), which is comparable to the third trimester of human pregnancy, induces neuronal cell loss. However, the molecular mechanisms underlying these neuronal losses are still poorly understood. Here, we tested the possibility of histone methylation mediated by G9a (lysine dimethyltransferase) in regulating neuronal apoptosis in P7 mice exposed to ethanol. G9a protein expression, which is higher during embryogenesis and synaptogenic period compared to adult brain, is entirely confined to the cell nuclei in the developing brain. We found that ethanol treatment at P7, which induces apoptotic neurodegeneration in neonatal mice, enhanced G9a activity followed by increased histone H3 lysine 9 (H3K9me2) and 27 (H3K27me2) dimethylation. In addition, it appears that increased dimethylation of H3K9 makes it susceptible to proteolytic degradation by caspase-3 in conditions in which ethanol induces neurodegeneration. Further, pharmacological inhibition of G9a activity prior to ethanol treatment at P7 normalized H3K9me2, H3K27me2 and total H3 proteins to basal levels and prevented neurodegeneration in neonatal mice. Together, these data demonstrate that G9a mediated histone H3K9 and K27 dimethylation critically regulates ethanol-induced neurodegeneration in the developing brain. Furthermore, these findings reveal a novel link between G9a and neurodegeneration in the developing brain exposed to postnatal ethanol and may have a role in fetal alcohol spectrum disorders.

Original languageEnglish (US)
Pages (from-to)475-485
Number of pages11
JournalNeurobiology of Disease
Volume54
DOIs
StatePublished - Jun 1 2013

Keywords

  • Bix
  • Developing brain
  • Fetal alcohol syndrome
  • Methyltransferase
  • Neuronal loss

ASJC Scopus subject areas

  • Neurology

Fingerprint Dive into the research topics of 'G9a-mediated histone methylation regulates ethanol-induced neurodegeneration in the neonatal mouse brain'. Together they form a unique fingerprint.

  • Cite this

    Subbanna, S., Shivakumar, M., Umapathy, N. S., Saito, M., Mohan, P. S., Kumar, A., Nixon, R. A., Verin, A. D., Psychoyos, D., & Basavarajappa, B. S. (2013). G9a-mediated histone methylation regulates ethanol-induced neurodegeneration in the neonatal mouse brain. Neurobiology of Disease, 54, 475-485. https://doi.org/10.1016/j.nbd.2013.01.022