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Goh, J.

Publications and source records attributed to Goh, J..

2 recordsLinked to original sources
bioRxiv2023

1.7 GHz long-term evolution radiofrequency electromagnetic field with efficient thermal control has no effect on the proliferation of different human cell types

Long-term evolution (LTE) radiofrequency electromagnetic field (RF-EMF) is widely used in communication technologies. As a result, the influence of RF-EMF on biological systems is a major public concern, and its physiological effects remain controversial. In our previous study, we showed that continuous exposure of various human cell types to 1.7 GHz LTE RF-EMF at specific absorption rate (SAR) of 2 W/Kg for 72 h can induce cellular senescence. To understand the precise cellular effects of LTE RF-EMF, we elaborated the 1.7 GHz RF-EMF cell exposure system used in the previous study by replacing the RF signal generator and developing a software-based feedback system to improve the exposure power stability. This refinement of the 1.7 GHz LTE RF-EMF generator facilitated the automatic regulation of RF-EMF exposure, maintaining target power levels within a 3% range and a constant temperature even during the 72-h exposure period. With the improved experimental setup, we examined the effect of continuous exposure to 1.7 GHz LTE RF-EMF at up to SAR of 8 W/Kg of adipose tissue-derived stem cells and Huh7, HeLa, and B103 cells. Surprisingly, the proliferation of all cell types, which displayed different growth rates, did not change significantly compared with that of the unexposed controls. However, when the thermal control system was turned off and the subsequent temperature increase induced by the RF-EMF was not controlled during continuous exposure to SAR of 8 W/Kg LTE RF-EMF, cellular proliferation increased by 35.2% at the maximum. These observations strongly suggest that the cellular effects attributed to 1.7 GHz LTE RF-EMF exposure were primarily due to the induced thermal changes, rather than the RF-EMF exposure itself.

cell biology↗
bioRxiv2022

Human gut Actinobacteria boost drug absorption by secreting P-glycoprotein ATPase inhibitors

Drug efflux transporters are a major determinant of drug efficacy and toxicity. A canonical example is P-glycoprotein (P-gp), an efflux transporter that controls the intestinal absorption of diverse compounds. Despite reports that P-gp expression depends on the microbiome, the mechanisms responsible and their physiological relevance remain unclear. Surprisingly, we found that the cardiac drug-metabolizing gut Actinobacterium Eggerthella lenta increases drug absorption in mice through post-translational inhibition of P-gp ATPase efflux activity. P-gp inhibition is conserved in the Eggerthellaceae family but absent in other Actinobacteria. Comparative genomics identified genes associated with P-gp inhibition. Finally, activity-guided biochemical fractionation coupled to metabolomics identified a cluster of isoflavonoids produced by E. lenta related to plant-derived P-gp inhibitors. These results highlight the unexpected overlap between diet- and microbiome-derived compounds, and the importance of considering the broader relevance of the gut microbiome for drug disposition beyond first-pass metabolism. One Sentence SummaryThe gut bacterium Eggerthella lenta secretes inhibitors of P-glycoprotein ATPase activity, accelerating drug absorption.

microbiology↗