研究のタイプ: 医学/生物学の研究 (experimental study)

[酸性スフィンゴミエリナーゼは50Hz磁界による脂質ラフト上のEGF受容体クラスター化を仲介する] med./bio.

Acid sphingomyelinase mediates 50-Hz magnetic field-induced EGF receptor clustering on lipid raft.

掲載誌: J Recept Signal Transduct Res 2016; 36 (6): 593-600

この研究は、著者らが以前に報告した50Hz磁界MF)による細胞膜表面での上皮成長因子受容体(EGFR)クラスタリングおよびリン酸化について、そのメカニズムにおける酸性スフィンゴミエリナーゼ(ASMase)および脂質ラフトの役割を検討した。ヒト羊膜上皮(FL)細胞にMF(50Hz、0.4 mT)ばく露をさまざまなばく露時間で与えた。細胞内ASMase活性は市販キットで、細胞膜表面のEGFRクラスタリング、ASMase、脂質ラフトは免疫蛍光染色後の共焦点顕微鏡法で評価した。その結果、ナイスタチン投与による脂質ラフトの乱れがあるとMF誘導性EGFRクラスタリングは阻害された;MFばく露によりASMase活性が上昇し、脂質ラフトが存在する膜ドメインへのASMaseの移行が誘導された;ASMase阻害剤投与により、MF誘導性EGFRクラスタリングは阻害された、と報告している。

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研究目的(著者による)

The roles of acid sphingomyelinase and lipid rafts in EGF receptor clustering during exposure of human amnion epithelial cells to a 50 Hz magnetic field should be investigated.

詳細情報

Previous studies by the authors found that exposing cells to a 50 Hz magnetic field could induce epidermal growth factor receptor (EGFR) clustering, suggesting that EGFR might be one of the cellular targets of EMF (Sun et al. 2008, Ke et al. 2008). In the present study, associated mechanisms of action and signal transduction should be investigated.
Cells were either exposed to the magnetic field or sham exposed. Some samples were pretreated with nystatin (60 µg/ml), a lipid raft inhibitor, or with imipramine (50 µM), a specific inhibitor of acid sphingomyelinase. Moreover, some samples were treated with C2-ceramide (50 µg/ml), the product of the acid sphingomyelinase, after exposure.
A positive control was conducted.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 50 Hz
ばく露時間: continuous for 5, 15, 30 or 60 minutes

ばく露1

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 5, 15, 30 or 60 minutes
ばく露装置
ばく露の発生源/構造
チャンバの詳細 cell dishes in exposure in chambers in incubator
ばく露装置の詳細 exposure system consisted of two exposure chambers (one for exposure and one for sham exposure), which were put in a CO2 incubator, and a set of control devices outside the incubator; each chamber contained a set of square Helmholtz coils (20 cm x 20 cm) which were double wrapped with two lines of copper wire and was encased by mu-metal; a fan on the metal wall ventilated and maintained air and temperature uniform between chamber and incubator; current was fed into the coils with the same direction in the exposure chamber, whereas opposite direction currents were fed into the coils in the sham exposure chamber; the incubator was aired with 95% humidity air and 5% CO2; the temperature in the chambers was maintained at 37.0°C ± 0.1°C throughout the entire exposure period; the difference in temperature between the chambers did not exceed 0.1°C; cell dishes were put in the center of the coils and the magnetic field was perpendicular to the dishes
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.4 mT - 測定値 - -

Reference articles

ばく露を受けた生物:

方法 影響評価項目/測定パラメータ/方法

研究対象とした生物試料:
調査の時期:
  • ばく露中
  • ばく露後

研究の主なアウトカム(著者による)

Exposure to the magnetic field for 15 min significantly increased the clustering of EGF receptors in cells compared to sham exposed cells, as it was expected from previous studies. However, pretreatment with nystatin almost completely inhibited the MF-induced EGFR clustering, indicating that it required intact lipid rafts.
Moreover, exposure to the magnetic field for 15 or 30 minutes significantly increased the enzyme activity of acid sphingomyelase compared to sham exposed cells.
It was shown that exposure to the magnetic field for 15 minutes induced lipid raft and acid sphingomyelase clustering and co-location on the cell membrane. The magnetic field-induced EGFR clustering was inhibited completely by imipramine. When C2-ceramide was added to the medium, the MF-induced EGFR clustering was restored.
The authors conclude that the results indicate that acid sphingomyelase mediates the 50 Hz magnetic field-induced EGFR clustering via ceramide generation on lipid rafts in human amnion epithelial cells.

研究の種別:

研究助成

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