RNAseq analysis of heart tissue from mice treated with atenolol and isoproterenol reveals a reciprocal transcriptional response

The transcriptional response to many widely used drugs and its modulation by genetic variability is poorly understood. Here we present an analysis of RNAseq profiles from heart tissue of 18 inbred mouse strains treated with the ß-blocker atenolol (ATE) and the ß-agonist isoproterenol (ISO). Differential expression analyses revealed a large set of genes responding to ISO (n=1770 at FDR=0.0001) and a comparatively small one responding to ATE (n=23 at FDR=0.0001). At a less stringent definition of differential expression, the transcriptional responses to these two antagonistic drugs are reciprocal for many genes, with an overall anti-correlation of r= -0.3. This trend is also observed at the level of most individual strains even though the power to detect differential expression is significantly reduced. The inversely expressed gene sets are enriched with genes annotated for heart-related functions. Modular analysis revealed gene sets that exhibited coherent transcription profiles across some strains and/or treatments. Correlations between such modules and a broad spectrum of cardiovascular traits are stronger than expected by chance. This provides evidence for the overall importance of transcriptional regulation for these organismal responses and explicits links between co-expressed genes and the traits they are associated with. Gene set enrichment analysis of differentially expressed groups of genes pointed to pathways related to heart development and functionality. Our study provides new insights into the transcriptional response of the heart to perturbations of the ß-adrenergic system, implicating several new genes that had not been associated to this system previously. Overall design: Cardiac mRNA expression profiles of the various inbred mouse strains were examined either under baseline condition (control) or in response to chronic administration of isoproterenol or atenolol at 10 mg/kg per day for 2 weeks. Expression data were produced by RNA-sequencing, in triplicates, using the HiSeq 2000 Illumina platform. Only males, aged ten to twelve weeks on average, were included in the experimental protocol. Mouse ID numbers refer to those described in Berthonneche C. et al. PLoS One. 2009 Aug 12;4(8):e6610 (doi: 10.1371/journal.pone.0006610. PMID: 19672458). Corresponding individual phenotypic values, in particular heart rate, systolic blood pressure, electrocardiogaphic measurements and heart weight are available in dataset "maurer1" of the Mouse Phenome Database (http://phenome.jax.org/). Preparation of the sequencing libraries, RNA-sequencing and RNA expression quantitations were performed by the BGI.

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Prunotto A, Stevenson BJ, Berthonneche C, Schüpfer F, Beckmann JS, Maurer F, Bergmann S