Sex differences in RNA transcripts in dilated cardiomyopathy

Abstract Introduction Dilated cardiomyopathy (DCM) is the most common cardiomyopathy and a major cause of heart failure. Differences in clinical presentation and phenotype exist in men and women but the reason for this is not clear. The analysis of the RNA transcripts (mRNA sequencing) offers an opportunity to provide a link between the genome, the proteome, and the phenotype. The aim of this study was to explore sex differences using mRNA sequencing in patients with DCM. Method Our database, an observational prospective cohort study, includes patients referred for suspected cardiomyopathy. The database includes data on patients’ characteristics, symptoms, diagnostic procedures, treatments, cardiac devices, and outcome. Endomyocardial biopsy from the right ventricle was collected and total RNA, including miRNA and other small RNA, was isolated. RNA sequencing and library preparation was performed. Following quality check, reads were aligned to GRCh38 reference genome by STAR (v2.7.10a). Sex-specific differential expression analysis between individuals diagnosed with DCM (cases) versus non-confirmed cardiomyopathy (controls) was performed using DESeq2 (v.1.38.3) adjusting for age, RNA integrity number and systolic blood pressure. After controlling for multiple testing using the Benjamini-Hochberg method, genes with a corrected P-value < 0.05 were considered as being differentially expressed. Gene-set enrichment analysis on differentially expressed genes was performed via Enrichr tool using Descartes cell types and tissues, KEGG biological pathways, DisGeNET, and Gene Ontology Biological Processes (GOBP). Results Patients´characteristics in women and men with DCM is presented in table 1. There was no difference in outcome in men and women (data not shown). Differential expression analyses with transcriptomic data comparing DCM (n=43) versus controls (n=22) stratified by sex (DCM n= 9, (20.9%) women and controls n=7, (30.4%) women) was performed. There was no overlap between differentially expressed genes between sexes (Figure 1). In men gene set enrichment analyses showed that differentially expressed genes were related to pathways involved in dilated and hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy (KEGG). Interestingly, these analyses revealed an enrichment of genes related to platelet biology, namely precursors (Descartes), activation (GOBP, KEGG) and platelet disorder (DisGeNET). In women, HLA-DQB1 was more expressed in DCM. HLA-DQB1 is associated with celiac disease, narcolepsy, and type 1 diabetes. Consistently, the enrichment analyses showed an enrichment of genes involved in autoimmune diseases (DisGeNET). Conclusion Women and men with DCM exhibit differently activated RNA transcripts although no difference in phenotype was observed. This may indicate that although DCM can be caused by similar factors in women and men the transcriptome is differently activated which warrants further investigation.Table 1.