DNA methylation changes in human lung epithelia cells exposed to multi-walled carbon nanotubes

Abstract

Humans are increasingly exposed to nanoparticles and, although many of their physiological effects have been described, the molecular mechanisms underlying them are still largely unknown. The present study aimed to determine the possible role of certain epigenetic mechanisms in the cellular response of human lung epithelial cells that are triggered by long-term exposure to titanium dioxide nanoparticles (TiO₂NPs) and multi-walled carbon nanotubes (MWCNTs). The results showed that exposure to TiO₂NPs had only minor effects on genome-wide DNA methylation. However, we identified 755 CpG sites showing consistent DNA hypomethylation in cells exposed to MWCNTs. These sites were mainly located at low density CpG regions and enhancers, and very frequently on the X chromosome. Our results thus suggest that long-term MWCNT exposure may have important effects on the epigenome.

Keywords:

• Epigenetics
• DNA methylation
• nanomaterials
• exposure

Acknowledgments

We thank Ronnie Lendrum for editorial assistance.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work has been financially supported by the Plan Nacional de I + D + I 2008-2011/2013-2016/FEDER (PI11/01728 to A.F.F.; PI12/01080 and PI15/00892 to M.F.F.); IUOPA (to MIS, CM and GFB). A.F.F. is supported by a Miguel Servet II grant (contract CPII16/00007). The IUOPA is supported by the Obra Social Liberbank-Cajastur, Spain.