Abstract Summary
Over 5 million teenagers in the United States reported smoking an e-cigarette in 2019. Although e-cigarette products such as JUULs are rapidly growing in popularity, many users believe e-cigarettes are safe. Furthermore, there are limited studies rigorously analyzing vascular and genetic changes induced by smoking JUULS. We present a rigorous analysis of transcriptomic (bulk RNA sequence) data from endothelial cells derived from human JUUL smokers and non-product users. Endothelial cells line the vasculature and their dysfunction is the first sign of vascular damage. Thus, our research presents an improved model for understanding cardiovascular damage and dysfunction.
Venal endothelial cells were collected from a total of 9 young, healthy JUUL smokers and non-product users and bulk RNA sequencing was performed. I developed a four-tiered statistical framework to analyze differential gene expression of endothelial cells from JUUL smokers. This framework is able to [1] identify overall (global) endothelial cell gene expression differences between JUUL smokers and non-smokers, [2] rank differentially expressed genes, [3] characterize biological products of the sequences, [4] and characterize altered cellular pathways. In particular, we hypothesized differential expression would be noted highest in genes relating to fibrosis, DNA repair, and inflammation.
I discovered 127 transcriptome sequences were differentially expressed in JUUL smokers (with a fold change >1.5 and False Discovery Rate, q-value, of <0.05). I also found markers of vascular inflammation, fibrosis, and abnormal growth to be differentially expressed. A novel transcript involved in gene regulation was also identified which appears to be a promising candidate for therapy.
My findings suggest that smoking e-cigarettes results in genetic expression changes and leads to vascular damage. This is particularly concerning because younger age groups are gaining access to e-cigarettes and the e-cigarette industry is largely unregulated.We hope to continue analysis to influence FDA regulation and improve educational outreach material to reduce the number of e-cigarette smokers.
Endothelial cells were collected from the cubital vein and magnetically separated. Bulk-RNA sequencing was subsequently performed.
A heat map of the top 20 differentially expressed shows patterns of sequence upregulation in the endothelial cell gene expression of JUUL smokers. The rows are the gene sequences; the blue columns represent non-product users and pink columns represent JUUL smokers. As red intensity increases, the genes are more up-regulated. The grouping is performed by an unsupervised hierarchical clustering algorithm implemented when generating the figure in R.