Activation of matrix metalloproteinases and FoxO3a in HaCaT keratinocytes by radiofrequency electromagnetic field exposure

Jun-Sang Bae,Hyung-Gun Kim,Hak Rim Kim,Dong-Jun Kang,Ju Hwan Kim,Hyung-Do Choi,Sangbong Jeon,Nam Kim,Jai Hyuen Lee

doi:10.1038/s41598-021-87263-2

Abstract

As the skin is the largest body organ and critically serves as a barrier, it is frequently exposed and could be physiologically affected by radiofrequency electromagnetic field (RF-EMF) exposure. In this study, we found that 1760 MHz RF-EMF (4.0 W/kg specific absorption rate for 2 h/day during 4 days) exposure could induce intracellular reactive oxygen species (ROS) production in HaCaT human keratinocytes using 2′,7′-dichlorofluorescin diacetate fluorescent probe analysis. However, cell growth and viability were unaffected by RF-EMF exposure. Since oxidative stress in the skin greatly influences the skin-aging process, we analyzed the skin senescence-related factors activated by ROS generation. Matrix metalloproteinases 1, 3, and 7 (MMP1, MMP3, and MMP7), the main skin wrinkle-related proteins, were significantly increased in HaCaT cells after RF-EMF exposure. Additionally, the gelatinolytic activities of secreted MMP2 and MMP9 were also increased by RF-EMF exposure. FoxO3a (Ser318/321) and ERK1/2 (Thr 202/Tyr 204) phosphorylation levels were significantly increased by RF-EMF exposure. However, Bcl2 and Bax expression levels were not significantly changed, indicating that the apoptotic pathway was not activated in keratinocytes following RF-EMF exposure. In summary, our findings show that exposure to 1760 MHz RF-EMF induces ROS generation, leading to MMP activation and FoxO3a and ERK1/2 phosphorylation. These data suggest that RF-EMF exposure induces cellular senescence of skin cells through ROS induction in HaCaT human keratinocytes.

Highlights

As the skin is the largest body organ and critically serves as a barrier, it is frequently exposed and could be physiologically affected by radiofrequency electromagnetic field (RF-EMF) exposure
Since reactive oxygen species (ROS) generation in the skin is one of the main causes of skin aging, ROS generation in HaCaT cells induced by RF-EMF exposure was measured using the fluorescent probe 2′,7′-dichlorofluorescin diacetate (DCF-DA)
We analyzed ROS production levels in whole cells using flow cytometry with Flow Jo software. These data indicated that intracellular ROS production was increased to 15.7% in HaCaT cells after RF-EMF exposure, showing that 58.3% of RF-EMF-exposed cells were stained with DCF (41.7% cells unstained with DCF; Fig. 1B c), whereas 42.6% of the control cells were stained with DCF (57.4% cells unstained with DCF; Fig. 1B b)

Summary

Introduction

As the skin is the largest body organ and critically serves as a barrier, it is frequently exposed and could be physiologically affected by radiofrequency electromagnetic field (RF-EMF) exposure. Since oxidative stress in the skin greatly influences the skinaging process, we analyzed the skin senescence-related factors activated by ROS generation. Our findings show that exposure to 1760 MHz RF-EMF induces ROS generation, leading to MMP activation and FoxO3a and ERK1/2 phosphorylation. These data suggest that RF-EMF exposure induces cellular senescence of skin cells through ROS induction in HaCaT human keratinocytes. Public concern about the possible harmful effects of radiofrequency electromagnetic fields (RF-EMF) generated by electronic devices on the human body is continuously increasing. RF-EMFs stimulate ROS generation both in vivo[6,7] and in vitro[8,9]

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Results

Conclusion