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.
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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.
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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.