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Increased levels of inducible HSP70 in cells exposed to electromagnetic fields.

Radiation research · 2006 · Mixed · Low evidence

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MixedLow evidencePaper 5145

In several cell models, some cell types showed increased inducible HSP70 protein levels after 24 h exposure to 50 Hz, 680 microT EMFs. In endothelial cells, EMFs alone caused only poor/transient HSF1 activation and did not significantly alter HSP70 mRNA level…

Study snapshot

PublicationRadiation research · 2006
Study typein_vitro
Reported directionMixed
Evidence ratingLow

Abstract

Because reports in the literature on the effects of electromagnetic fields (EMFs) on expression of the 70-kDa heat-shock protein (HSP70) are somewhat contradictory, we studied the influence of low-frequency EMFs on the accumulation of inducible HSP70 in several cell models. Some of the cell types tested showed increased levels of HSP70 protein when exposed for 24 h to 50 Hz, 680 microT EMFs. In endothelial cells, EMFs alone induced only a poor and transient activation of the heat-shock transcription factor 1 (HSF1); however, neither the level of HSP70 mRNA nor the synthesis of HSP70 appeared to be altered significantly. Accordingly, transfection experiments involving HSP70 promoter showed that gene transcription was not affected. We also noted a marked reduction in proteasome activities in cell extracts exposed to EMFs. Interestingly, the heat-shock-induced levels of HSP70 mRNA and protein were increased by a concomitant weak stressor like EMFs. Taken together, our results indicate that in EMF-exposed endothelial cells, HSP70 gene transcription and translation are unaffected; however, EMFs alone promoted accumulation of the inducible HSP70 protein, probably by increasing its stability, and it enhanced accumulation and translation of the heat-induced HSP70 mRNA when applied in concert with heat shock.

Machine Enhanced Logic

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 directionmixed
PopulationNot supplied
Sample sizeNot supplied
ExposureELF · 0.05 MHz · 24 h
Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

In several cell models, some cell types showed increased inducible HSP70 protein levels after 24 h exposure to 50 Hz, 680 microT EMFs. In endothelial cells, EMFs alone caused only poor/transient HSF1 activation and did not significantly alter HSP70 mRNA levels, HSP70 synthesis, or HSP70 promoter-driven transcription, but were associated with reduced proteasome activity and increased accumulation of inducible HSP70 protein; EMFs also increased heat-shock-induced HSP70 mRNA and protein when combined with heat shock.

Outcomes measured

  • Inducible HSP70 protein levels/accumulation
  • HSF1 activation
  • HSP70 mRNA levels
  • HSP70 synthesis/translation
  • HSP70 promoter activity (transfection)
  • Proteasome activity
  • Heat-shock-induced HSP70 mRNA and protein (with concomitant EMF exposure)

Limitations

  • Sample size not reported in abstract
  • Specific cell models and number of cell types not detailed in abstract
  • Mechanistic interpretation (e.g., increased protein stability) is not directly demonstrated in the abstract
View raw extracted JSON
{
  "study_type": "in_vitro",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 0.05,
    "sar_wkg": null,
    "duration": "24 h"
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Inducible HSP70 protein levels/accumulation",
    "HSF1 activation",
    "HSP70 mRNA levels",
    "HSP70 synthesis/translation",
    "HSP70 promoter activity (transfection)",
    "Proteasome activity",
    "Heat-shock-induced HSP70 mRNA and protein (with concomitant EMF exposure)"
  ],
  "main_findings": "In several cell models, some cell types showed increased inducible HSP70 protein levels after 24 h exposure to 50 Hz, 680 microT EMFs. In endothelial cells, EMFs alone caused only poor/transient HSF1 activation and did not significantly alter HSP70 mRNA levels, HSP70 synthesis, or HSP70 promoter-driven transcription, but were associated with reduced proteasome activity and increased accumulation of inducible HSP70 protein; EMFs also increased heat-shock-induced HSP70 mRNA and protein when combined with heat shock.",
  "effect_direction": "mixed",
  "limitations": [
    "Sample size not reported in abstract",
    "Specific cell models and number of cell types not detailed in abstract",
    "Mechanistic interpretation (e.g., increased protein stability) is not directly demonstrated in the abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ELF-EMF",
    "50 Hz",
    "680 microT",
    "HSP70",
    "heat shock protein 70",
    "HSF1",
    "endothelial cells",
    "proteasome activity",
    "gene transcription",
    "translation",
    "protein stability",
    "heat shock"
  ],
  "suggested_hubs": [
    {
      "slug": "elf-emf",
      "weight": 0.9,
      "reason": "In vitro exposure to low-frequency (50 Hz) electromagnetic fields with microtesla flux density."
    }
  ]
}
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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: 10.1667/rr3487.1
PubMed: 16392967

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