Abstract 13011: RNA-Seq Analysis of Human Abdominal Aorta Samples Identifies Putative Markers for Early Stage Atherosclerosis

Introduction: Atherosclerosis can be defined as an assembly of hundreds of intra- and extra-cellular expressed genes that jointly alter cellular processes and produce characteristic remodeling of the local tissue environment. To improve early detection, and to interrupt the disease process before clinical consequences occur, it is necessary to recognize and understand the specific patterns of expressed genes that constitute the molecular signature of early atherosclerosis. To study this, we used RNA-Seq to identify expressed genes that are differentially abundant across normal and diseased human aortic tissues. Methods: Pairs of diseased (fatty streak (fs), fibrous plaque (fp), complex fibrous plaque (fc)) and adjacent normal (nl) grossly identified aortic samples were collected from coroner’s autopsies at the Louisiana State University (n=59). Each aortic specimen (100 mg tissue) was homogenized for total RNA extraction and generation of cDNA libraries which were sequenced by the Ion Proton™ System (Life Technology). RNA-Seq reads (avg. read length = 125) were evaluated using FASTQC for sequencing quality and aligned to the human reference genome using HISAT2. The RNA transcripts were assembled and quantified using StringTie. DESeq2 was used to compare expression levels for 16,827 genes passing QC across diseased and non-diseased samples. Results: Diseased samples had a large number of differentially expressed genes (DEGs) (fc:1731> fp:380 > fs:80) when compared with paired nl samples (Benjamin-Hochberg adjusted p-value < 0.05), including 70 genes expressed in mitochondria. GO enrichment analysis of the fs, fp and fc DEGs showed the top enriched biological processes for the advanced lesions (fp, fc) were mostly immune response related pathways while the top enriched processes in fs samples were mainly lipoprotein metabolism. A group of 42 genes were differentially expressed in all the diseased samples compared with their adjacent nl control samples. Conclusions: The differentially expressed genes identified here provide greater resolution concerning molecular dysregulation of lipoprotein and immune function pathways and reinforce emerging data concerning abnormal mitochondrial function in early atherosclerosis.