Effects of prolonged stimulation with heated tobacco products (Ploom TECH+) on gingival epithelial cells

Objective and Background: Heated tobacco products have recently become commercially available. These products, as well as combustible cigarettes, produce aerosols; the risk of various diseases associated with heated tobacco products may be the same as or higher than that with combustible cigarettes. In this study, we examined the effect of Ploom TECH+ extract on gingival epithelial cells.
Methods: Tobacco leaves from Ploom TECH+ tobacco capsules and water were mixed and heated; the supernatant subsequently collected was the heated tobacco product (HTP; control: HTP not added). Normal human gingival epithelial progenitors were cultured alternately with or without HTP for a total of 1 month. Subsequently, RNA, DNA, and proteins were isolated from these samples and comprehensively analyzed using RNA sequencing (RNA-seq), reduced representation bisulfite sequencing (RRBS), and western blotting, respectively.
Results: RNA-seq revealed that 284 genes showed a two-fold increase and 145 genes showed a two-fold decrease in gene expression. A heat map showed genetic differences between the control and HTP groups. A principal component analysis plot showed a clear genetic distribution between the control and HTP. Gene Ontology (GO) analysis showed that genes related to seven GO terms, including cornification and keratinization, were induced by long-term HTP stimulation. By contrast, GO pathways with a significant decrease in component expression were not detected. RRBS revealed that CpG island methylation increased more than two-fold in 158 genes and decreased to less than two-fold in 171 genes. Methylation of these CpG islands was not correlated with changes in gene expression levels. HTP treatment increased S100A7 expression.
Conclusion: Long-term HTP stimulation affected epithelial differentiation and keratinization of gingival epithelial cells. Thus, habitual use of Ploom TECH+ may be a risk factor for tobacco-related oral mucosal diseases.

This is the peer reviewed version of the following article: Uehara, O., Nakamoto, N., Hiraki, D., Paudel, D., Sugiyama, N., Morikawa, T., Yoshida, K., Kawano, Y., Shimo, T., Furuichi, Y., Miura, H. and Abiko, Y., Effects of prolonged stimulation with heated tobacco products (Ploom TECH+) on gingival epithelial cells. Journal of Periodontal Research, 58, 3, 553-563, which has been published in final form at https://doi.org/10.1111/jre.13123. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.