Submitted on July 30, 2006
Accepted on November 30, 2006
Cardiac myocyte gene expression profiling during H2O2-induced apoptosis
Angela Clerk1*, Timothy J Kemp1, Georgia Zoumpoulidou1, and Peter H. Sugden2
1 NHLI Division, Faculty of Medicine, Imperial College London, London, United Kingdom
2 NHLI Division (Cardiac Med), Imperial College School of Medicine, London, United Kingdom
* To whom correspondence should be addressed. E-mail: a.clerk{at}imperial.ac.uk.
High levels of oxidative stress promote cardiac myocyte death, though lower levels are potentially cytoprotective/anabolic. We examined the changes in gene expression in rat neonatal cardiac myocytes exposed to apoptotic (0.2 mM) or non-toxic (0.04 mM) concentrations of H2O2 (2, 4 or 24 h) using Affymetrix microarrays. Using U34B arrays, we identified a ubiquitously-expressed, novel H2O2-responsive gene [putative peroxide-inducible transcript 1 (Perit1)] which generates two alternatively-spliced transcripts. Using 230 2.0 arrays, H2O2 (0.04 mM) promoted significant changes in expression of only 32 genes, all of which were seen with 0.2 mM H2O2. We failed to detect any increase in the rate of protein synthesis in cardiac myocytes exposed to <0.1 mM H2O2, further suggesting that global, low concentrations of H2O2 are not anabolic in this system. H2O2 (0.2 mM) promoted significant (p<0.05; >1.75-fold) changes in expression of 649 mRNAs and 187 RNAs corresponding to no established gene. Of the mRNAs, 114 encoded transcriptional regulators including Kruppel-like factors (Klfs). Quantitative PCR independently verified the changes in Klf expression. Thus, H2O2-induced cardiac myocyte apoptosis is associated with dynamic changes in gene expression. The expression of these genes and their protein products potentially influences the progression of the apoptotic response.
