The arrhythmogenic cardiomyopathy-specific coding and non-coding transcriptome in human cardiac stromal cells

Background: Arrhythmogenic cardiomyopathy (ACM) is a genetic autosomal disease characterized by abnormal cell-cell adhesion, cardiomyocyte death, progressive fibro-adipose replacement of the myocardium, arrhythmias and sudden death. Several different cell types contribute to the pathogenesis of ACM, including, as recently described, cardiac stromal cells (CStCs). In the present study, we aim to identify ACM-specific expression profiles of human CStCs derived from endomyocardial biopsies of ACM patients and healthy individuals employing TaqMan Low Density Arrays for miRNA expression profiling, and high throughput sequencing for gene expression quantification. Results: We identified 5 miRNAs and 272 genes as significantly differentially expressed. Both the differentially expressed genes as well as the target genes of the ACM-specific miRNAs were found to be enriched in cell adhesion related biological processes. Functional similarity and protein interaction based network analyses performed on the identified deregulated genes, miRNA targets and known ACM-causative genes revealed clusters of highly related genes involved in cell adhesion, extracellular matrix organization, lipid transport and ephrin receptor signaling. Conclusions: We determined for the first time the coding and non-coding transcriptome characteristic of ACM cardiac stromal cells, finding evidence for a potential contribution of miRNAs to ACM pathogenesis or phenotype maintenance. Besides known pathways, we identified also deregulation of genes encoding ephrin receptors and ephrins, thus suggesting a potential involvement of Eph-ephrin signaling in CStCs from ACM hearts. Overall design: Expression profiles of cardiac stromal cells from 3 ACM patients were compared against those of cardiac stromal cells from 3 healthy individuals.