Short ELF-EMF Exposure Targets SIRT1/Nrf2/HO-1 Signaling in THP-1 Cells.

International journal of molecular sciences · 2020 · Benefit · Low evidence

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BenefitLow evidencePaper 5624

Study snapshot

PublicationInternational journal of molecular sciences · 2020

Study typein_vitro

Reported directionBenefit

Evidence ratingLow

Abstract

Extremely low frequency electromagnetic fields (ELF-EMFs) have been known to modulate inflammatory responses by targeting signal transduction pathways and influencing cellular redox balance through the generation of oxidants and antioxidants. Here, we studied the molecular mechanism underlying the anti-oxidative effect of ELF-EMF in THP-1 cells, particularly with respect to antioxidant enzymes, such as heme oxygenase-1 (HO-1), regulated transcriptionally through nuclear factor E2-related factor 2 (Nrf2) activation. Cells treated with lipopolysaccharides (LPS) were exposed to a 50 Hz, 1 mT extremely low frequency electromagnetic fields for 1 h, 6 h and, 24 h. Our results indicate that ELF-EMF induced HO-1 mRNA and protein expression in LPS-treated THP-1 cells, with peak expression at 6 h, accompanied with a concomitant migration to the nucleus of a truncated HO-1 protein form. The immunostaining analysis further verified a nuclear enrichment of HO-1. Moreover, ELF-EMF inhibited the protein expressions of the sirtuin1 (SIRT1) and nuclear factor kappa B (NF-kB) pathways, confirming their anti-inflammatory/antioxidative role. Pretreatment with LY294002 (Akt inhibitor) and PD980559 (ERK inhibitor) inhibited LPS-induced Nrf2 nuclear translocation and HO-1 protein expression in ELF-EMF-exposed cells. Taken together, our results suggest that short ELF-EMF exposure exerts a protective role in THP-1 cells treated with an inflammatory/oxidative insult such as LPS, via the regulation of Nrf-2/HO-1 and SIRT1 /NF-kB pathways associated with intracellular glutathione (GSH) accumulation.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typein_vitro

Effect directionbenefit

PopulationTHP-1 cells (LPS-treated)

Sample sizeNot supplied

ExposureELF · 0.05 MHz · 1 h, 6 h, and 24 h

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

In LPS-treated THP-1 cells, exposure to 50 Hz, 1 mT ELF-EMF increased HO-1 mRNA and protein expression (peak at 6 h) and was associated with nuclear enrichment of a truncated HO-1 form and Nrf2 activation. ELF-EMF exposure inhibited SIRT1 and NF-κB pathway protein expression, and Akt/ERK inhibitors reduced ELF-EMF-associated Nrf2 nuclear translocation and HO-1 protein expression.

Outcomes measured

HO-1 mRNA expression
HO-1 protein expression
Nrf2 nuclear translocation/activation
Nuclear localization of truncated HO-1
SIRT1 protein expression
NF-κB pathway protein expression
Intracellular glutathione (GSH) accumulation
Effects of Akt inhibitor (LY294002) and ERK inhibitor (PD980559) on Nrf2/HO-1 responses

Limitations

In vitro study in a single cell line (THP-1) under LPS-induced inflammatory/oxidative conditions
No sample size or replication details provided in the abstract
Only one ELF-EMF condition reported (50 Hz, 1 mT) with short exposure durations

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 0.05,
    "sar_wkg": null,
    "duration": "1 h, 6 h, and 24 h"
  },
  "population": "THP-1 cells (LPS-treated)",
  "sample_size": null,
  "outcomes": [
    "HO-1 mRNA expression",
    "HO-1 protein expression",
    "Nrf2 nuclear translocation/activation",
    "Nuclear localization of truncated HO-1",
    "SIRT1 protein expression",
    "NF-κB pathway protein expression",
    "Intracellular glutathione (GSH) accumulation",
    "Effects of Akt inhibitor (LY294002) and ERK inhibitor (PD980559) on Nrf2/HO-1 responses"
  ],
  "main_findings": "In LPS-treated THP-1 cells, exposure to 50 Hz, 1 mT ELF-EMF increased HO-1 mRNA and protein expression (peak at 6 h) and was associated with nuclear enrichment of a truncated HO-1 form and Nrf2 activation. ELF-EMF exposure inhibited SIRT1 and NF-κB pathway protein expression, and Akt/ERK inhibitors reduced ELF-EMF-associated Nrf2 nuclear translocation and HO-1 protein expression.",
  "effect_direction": "benefit",
  "limitations": [
    "In vitro study in a single cell line (THP-1) under LPS-induced inflammatory/oxidative conditions",
    "No sample size or replication details provided in the abstract",
    "Only one ELF-EMF condition reported (50 Hz, 1 mT) with short exposure durations"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ELF-EMF",
    "50 Hz",
    "1 mT",
    "THP-1",
    "lipopolysaccharide",
    "oxidative stress",
    "inflammation",
    "HO-1",
    "Nrf2",
    "SIRT1",
    "NF-κB",
    "glutathione",
    "Akt",
    "ERK"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.3390/ijms21197284
PubMed: 33023074

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