The frequency range of 60 GHz was considered in the context of their near-future applications in wireless communication systems. The endoplasmic reticulum is an organelle sensitive to a wide variety of environmental insults and involved in a number of pathologies and it is the site of synthesis and folding of secreted proteins. Perturbations of endoplasmic reticulum functions and the resulting induced pathway involves different transmembrane proteins or transcription factors (e.g. ATF6, XBP-1) which activate specific genes, such as the chaperone BiP/GRP78.
Separated transfection complexes were used: Cells were transfected with pSEAP (secreted alkaline phosphatase) reporter plasmid as marker for endoplasmic reticulum stress. This reporter enzyme is folded into its active conformation inside the endoplasmic reticulum, and only the correctly folded proteins are secreted into the medium.
Cells were transfected with BiP promoter-reporter plasmid to study stress-involved transcription factors XBP-1 and ATF6.
As endoplasmic reticulum-stress positive control, cells were treated for with thapsigargin or brefeldin or dimethyl sulfoxide.
|power density||0.14 mW/cm²||-||-||-||-|
Exposure to 60.4 GHz did not modify endoplasmic reticulum protein folding and secretion, nor induced XBP1 or ATF6 transcription factors maturation. There was no significant changes in gene expression of BiP/GRP78 and HSP70.
The data show that endoplasmic reticulum homeostasis does not undergo any modification at molecular level after exposure to low-power millimeter wave exposure at 60.4 GHz.