Ischemic Preconditioning Confers Epigenetic Repression of Mtor and Induction of Autophagy Through G9a-Dependent H3K9 Dimethylation

Olof Gidlöf, Andrea L. Johnstone, Kerstin Bader, Bohdan B. Khomtchouk, Jiaqi J. O'Reilly, Selvi Celik, Derek J. Van Booven, Claes R Wahlestedt, Bernhard Metzler, David Erlinge

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Background--Ischemic preconditioning (IPC) protects the heart from prolonged ischemic insult and reperfusion injury through a poorly understood mechanism. Post-translational modifications of histone residues can confer rapid and drastic switches in gene expression in response to various stimuli, including ischemia. The aim of this study was to investigate the effect of histone methylation in the response to cardiac ischemic preconditioning. Methods and Results--We used cardiac biopsies from mice subjected to IPC to quantify global levels of 3 of the most well-studied histone methylation marks (H3K9me2, H3K27me3, and H3K4me3) with Western blot and found that H3K9me2 levels were significantly increased in the area at risk compared to remote myocardium. In order to assess which genes were affected by the increase in H3K9me2 levels, we performed ChIP-Seq and transcriptome profiling using microarray. Two hundred thirty-seven genes were both transcriptionally repressed and enriched in H3K9me2 in the area at risk of IPC mice. Of these, Mtor (Mechanistic target of rapamycin) was chosen for mechanistic studies. Knockdown of the major H3K9 methyltransferase G9a resulted in a significant decrease in H3K9me2 levels across Mtor, increased Mtor expression, as well as decreased autophagic activity in response to rapamycin and serum starvation. Conclusions--IPC confers an increase of H3K9me2 levels throughout the Mtor gene-a master regulator of cellular metabolism and a key player in the cardioprotective effect of IPC-leading to transcriptional repression via the methyltransferase G9a. The results of this study indicate that G9a has an important role in regulating cardiac autophagy and the cardioprotective effect of IPC.

Original languageEnglish (US)
Article numbere004076
JournalJournal of the American Heart Association
Volume5
Issue number12
DOIs
StatePublished - Dec 1 2016

Fingerprint

Epigenetic Repression
Ischemic Preconditioning
Autophagy
Sirolimus
Methyltransferases
Histones
Methylation
Histone Code
Switch Genes
Genes
Gene Expression Profiling
Post Translational Protein Processing
Starvation
Reperfusion Injury
Myocardium
Ischemia
Western Blotting
Biopsy
Gene Expression

Keywords

  • Autophagy
  • Epigenetics
  • Ischemia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

Ischemic Preconditioning Confers Epigenetic Repression of Mtor and Induction of Autophagy Through G9a-Dependent H3K9 Dimethylation. / Gidlöf, Olof; Johnstone, Andrea L.; Bader, Kerstin; Khomtchouk, Bohdan B.; O'Reilly, Jiaqi J.; Celik, Selvi; Van Booven, Derek J.; Wahlestedt, Claes R; Metzler, Bernhard; Erlinge, David.

In: Journal of the American Heart Association, Vol. 5, No. 12, e004076, 01.12.2016.

Research output: Contribution to journalArticle

Gidlöf, O, Johnstone, AL, Bader, K, Khomtchouk, BB, O'Reilly, JJ, Celik, S, Van Booven, DJ, Wahlestedt, CR, Metzler, B & Erlinge, D 2016, 'Ischemic Preconditioning Confers Epigenetic Repression of Mtor and Induction of Autophagy Through G9a-Dependent H3K9 Dimethylation', Journal of the American Heart Association, vol. 5, no. 12, e004076. https://doi.org/10.1161/JAHA.116.004076
Gidlöf, Olof ; Johnstone, Andrea L. ; Bader, Kerstin ; Khomtchouk, Bohdan B. ; O'Reilly, Jiaqi J. ; Celik, Selvi ; Van Booven, Derek J. ; Wahlestedt, Claes R ; Metzler, Bernhard ; Erlinge, David. / Ischemic Preconditioning Confers Epigenetic Repression of Mtor and Induction of Autophagy Through G9a-Dependent H3K9 Dimethylation. In: Journal of the American Heart Association. 2016 ; Vol. 5, No. 12.
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abstract = "Background--Ischemic preconditioning (IPC) protects the heart from prolonged ischemic insult and reperfusion injury through a poorly understood mechanism. Post-translational modifications of histone residues can confer rapid and drastic switches in gene expression in response to various stimuli, including ischemia. The aim of this study was to investigate the effect of histone methylation in the response to cardiac ischemic preconditioning. Methods and Results--We used cardiac biopsies from mice subjected to IPC to quantify global levels of 3 of the most well-studied histone methylation marks (H3K9me2, H3K27me3, and H3K4me3) with Western blot and found that H3K9me2 levels were significantly increased in the area at risk compared to remote myocardium. In order to assess which genes were affected by the increase in H3K9me2 levels, we performed ChIP-Seq and transcriptome profiling using microarray. Two hundred thirty-seven genes were both transcriptionally repressed and enriched in H3K9me2 in the area at risk of IPC mice. Of these, Mtor (Mechanistic target of rapamycin) was chosen for mechanistic studies. Knockdown of the major H3K9 methyltransferase G9a resulted in a significant decrease in H3K9me2 levels across Mtor, increased Mtor expression, as well as decreased autophagic activity in response to rapamycin and serum starvation. Conclusions--IPC confers an increase of H3K9me2 levels throughout the Mtor gene-a master regulator of cellular metabolism and a key player in the cardioprotective effect of IPC-leading to transcriptional repression via the methyltransferase G9a. The results of this study indicate that G9a has an important role in regulating cardiac autophagy and the cardioprotective effect of IPC.",
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AU - Johnstone, Andrea L.

AU - Bader, Kerstin

AU - Khomtchouk, Bohdan B.

AU - O'Reilly, Jiaqi J.

AU - Celik, Selvi

AU - Van Booven, Derek J.

AU - Wahlestedt, Claes R

AU - Metzler, Bernhard

AU - Erlinge, David

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N2 - Background--Ischemic preconditioning (IPC) protects the heart from prolonged ischemic insult and reperfusion injury through a poorly understood mechanism. Post-translational modifications of histone residues can confer rapid and drastic switches in gene expression in response to various stimuli, including ischemia. The aim of this study was to investigate the effect of histone methylation in the response to cardiac ischemic preconditioning. Methods and Results--We used cardiac biopsies from mice subjected to IPC to quantify global levels of 3 of the most well-studied histone methylation marks (H3K9me2, H3K27me3, and H3K4me3) with Western blot and found that H3K9me2 levels were significantly increased in the area at risk compared to remote myocardium. In order to assess which genes were affected by the increase in H3K9me2 levels, we performed ChIP-Seq and transcriptome profiling using microarray. Two hundred thirty-seven genes were both transcriptionally repressed and enriched in H3K9me2 in the area at risk of IPC mice. Of these, Mtor (Mechanistic target of rapamycin) was chosen for mechanistic studies. Knockdown of the major H3K9 methyltransferase G9a resulted in a significant decrease in H3K9me2 levels across Mtor, increased Mtor expression, as well as decreased autophagic activity in response to rapamycin and serum starvation. Conclusions--IPC confers an increase of H3K9me2 levels throughout the Mtor gene-a master regulator of cellular metabolism and a key player in the cardioprotective effect of IPC-leading to transcriptional repression via the methyltransferase G9a. The results of this study indicate that G9a has an important role in regulating cardiac autophagy and the cardioprotective effect of IPC.

AB - Background--Ischemic preconditioning (IPC) protects the heart from prolonged ischemic insult and reperfusion injury through a poorly understood mechanism. Post-translational modifications of histone residues can confer rapid and drastic switches in gene expression in response to various stimuli, including ischemia. The aim of this study was to investigate the effect of histone methylation in the response to cardiac ischemic preconditioning. Methods and Results--We used cardiac biopsies from mice subjected to IPC to quantify global levels of 3 of the most well-studied histone methylation marks (H3K9me2, H3K27me3, and H3K4me3) with Western blot and found that H3K9me2 levels were significantly increased in the area at risk compared to remote myocardium. In order to assess which genes were affected by the increase in H3K9me2 levels, we performed ChIP-Seq and transcriptome profiling using microarray. Two hundred thirty-seven genes were both transcriptionally repressed and enriched in H3K9me2 in the area at risk of IPC mice. Of these, Mtor (Mechanistic target of rapamycin) was chosen for mechanistic studies. Knockdown of the major H3K9 methyltransferase G9a resulted in a significant decrease in H3K9me2 levels across Mtor, increased Mtor expression, as well as decreased autophagic activity in response to rapamycin and serum starvation. Conclusions--IPC confers an increase of H3K9me2 levels throughout the Mtor gene-a master regulator of cellular metabolism and a key player in the cardioprotective effect of IPC-leading to transcriptional repression via the methyltransferase G9a. The results of this study indicate that G9a has an important role in regulating cardiac autophagy and the cardioprotective effect of IPC.

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