Specific low-frequency electromagnetic fields induce expression of active KDM6B associated with functional changes in U937 cells

ABSTRACT

In this study, we investigated the effects of specific low-frequency electromagnetic field sequences on U937 cells, an in vitro model of human monocyte/macrophage differentiation. U937 cells were exposed to electromagnetic stimulation by means of the SynthéXer system using two similar sequences, XR-BC31 and XR-BC31/F. Each sequence was a time series of 29 wave segments, equal to a total duration of 77 min. Here, we report that exposure (4 d, once a day) of U937 cells to the XR-BC31 setting, but not to the XR-BC31/F, resulted in increased expression of the histone demethylase KDM6B along with a global reduction in histone H3 lysine 27 tri-methylation (H3K27me3). Furthermore, exposure to the XR-BC31 sequence induced differentiation of U937 cells towards a macrophage-like phenotype displaying a KDM6B dependent increase in expression and secretion of the anti-inflammatory interleukins (ILs), IL-10 and IL-4. Importantly, all the observed changes were highly dependent on the nature of the sequence. Our results open a new way of interpretation for the effects of low-frequency electromagnetic fields observed in vivo. Indeed, it is conceivable that a specific low-frequency electromagnetic fields treatment may cause the reprogramming of H3K27me3 and cell differentiation.

KEYWORDS:

• Electromagnetic fields
• demethylase KDM6B
• histone H3K27 tri-methylation
• monocyte/macrophage differentiation
• anti-inflammatory interleukins

Acknowledgments

We thank Prof. Giorgio Grosa and Prof. Gianpiero Gervino for helpful discussion and comments.

Author Contributions

GP carried out cellular and molecular studies and made substantial contributions to the analysis and interpretation of data. GP, AF, MB and ML participated in the design and coordination of the study and drafted the manuscript. All authors have read and approved the final manuscript.

Disclosure statement

Dr. Massimo Balma is CEO of Ethidea, the remaining authors declare that they have no competing interests.

Supplemental material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by Ethidea EXPREX project.