What is the impact of e-cigarettes on periodontal stem cells as revealed by transcriptomic analyses?

DESIGN

The research used an in vitro cell exposure model and multi-omics integration of transcriptome and epigenome profiling to compare the molecular effects of e-cigarettes and tobacco smoke on dental stem cells.

AIM

The study aimed to compare the effects of e-cigarette and tobacco smoke on periodontal stem cells using a multi-omics approach to understand gene regulation.

METHODS

This research studied primary human gingival mesenchymal stem cells (GMSCs) and periodontal ligament stem cells (PDLSCs) obtained from healthy donors. The cells were subjected to tobacco smoke, e-cigarette aerosol (both tobacco and menthol flavors), e-cigarette liquid (both tobacco and menthol flavors), or untreated conditions using an in vitro exposure system. RNA sequencing and bioinformatics analysis were used to profile the transcriptome and identify differential gene expression. Additionally, chromatin immunoprecipitation sequencing (ChIP-seq) was used to conduct genome-wide histone modification mapping for H3K27me3. Transcriptome profiling was combined with histone modification characterization to understand gene regulatory mechanisms. The study compared the effects of smoke versus e-cigarette, aerosol versus liquid exposure, and tobacco versus menthol flavor on gene expression and epigenetic landscapes in the two oral stem cell populations.

RESULTS

The use of tobacco smoke caused damage to the DNA and nucleus in GMSCs, as well as mitochondrial dysfunction in PDLSCs. Regarding e-cigarettes, the aerosol and liquid affected non-coding RNA expression differently. The chemokine CXCL2 was found to be downregulated by aerosol but upregulated by liquid in GMSCs. An integrative analysis revealed that the upregulation of CXCL2 caused by e-liquid involved reduced H3K27me3 and activation of distal enhancers. On the other hand, aerosol exposure maintained H3K27me3 levels, while direct e-liquid exposure resulted in genome-wide reductions in H3K27me3, particularly in enhancer regions. Overall, the specific delivery methods and components of e-cigarettes caused unique changes in the transcriptome and epigenome of oral stem cells.

CONCLUSIONS

E-cigarettes affect oral stem cells differently than tobacco smoke. Their aerosol and liquid have varying impacts on gene expression and regulatory landscapes in oral cells. Multi-omics approaches are important to understanding the molecular changes caused by e-cigarette components. This can help with toxicological assessments and determine their impact on periodontal health. Transcriptome and epigenome profiling are powerful tools to examine the unique molecular mechanisms involved in cellular responses to e-cigarettes.