Identifying candidate circulating RNA markers for coronary artery disease by deep RNA-Sequencing in human plasma

This study aimed to develop a short-read RNA-Seq protocol to detect mRNAs, lncRNAs and circRNAs (including putative novel lncRNAs) in human plasma. This protocol was applied to plasma from patients with established stable CAD (samples collected ~4 months after an acute coronary event) and healthy controls to screen for candidate mRNA, lncRNA and circRNA biomarkers associated with the presence of coronary artery disease and the progression from CAD to HF. We hypothesised that circulating levels of non-coding RNAs in patients with stable CAD may relect progression of atherosclerotic disease or adverse myocardial remodeling, and may help identify patients at risk of future cardiovascular events. Here we demonstrate that mRNAs, lncRNAs and circRNAs can be reliably detected in human plasma by deep RNA-Seq and report novel candidate biomarkers for the presence of CAD. Circulating cell-free RNA from 59 patients with stable CAD (half of whom developed HF within 3 years) and 30 controls was sequenced to a median depth of 108 paired reads per sample on an Illumina NovaSeq 6000 S1 flowcell.