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

[パルス電磁界は一次繊毛基部限局的なBMPRII発現を増加させることで骨芽細胞の骨形成分化および成熟を刺激する] med./bio.

Pulsed electromagnetic fields stimulate osteogenic differentiation and maturation of osteoblasts by upregulating the expression of BMPRII localized at the base of primary cilium.

掲載誌: Bone 2016; 93: 22-32

この研究は、先行研究で報告された、50Hz、0.6mTのパルス電磁界骨芽細胞分化骨形成刺激について更に調査した。その結果、パルス電磁界骨形成タンパク質BMP-Smad1/5/8シグナル伝達の活性化により、一次繊毛が正常な条件に対して、ラット頭蓋骨芽細胞骨形成分化および成熟を促進することが示された。更なる研究では、BMPリガンドの一次結合受容体であるBMPRIIが、パルス電磁界処理によって容易にかつ強く上方制御され、一次繊毛基部に限局化されることがわかった。著者らは、これらの結果は、パルス電磁界が一次繊毛が介在するBMPRII発現上方制御と、その後のBMP-Smad1/5/8シグナル伝達の活性化により、骨芽細胞分化および成熟を刺激すること、ならびに、BMPRIIは一次繊毛とBMP-Smad1/5/8経路を結ぶ重要な要素であることを示している、と結論付けている。

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研究目的(著者による)

The underlying mechanisms of action of osteogenic differentiation of rat osteoblasts induced by exposure to a 50 Hz pulsed magnetic field should be investigated.

詳細情報

In a previous study, the authors showed that 50 Hz pulsed magnetic field exposure could stimulate proliferation and osteogenic differentiation of rat osteoblasts and that the existence of a primary cilium is crucial for this effect (Yan et al. 2015). However, the mechanisms of action of this effect are not clear.
Rat calvarial osteoblasts were isolated from 10 neonatal rats and divided into different groups. For short term effects: exposure to the pulsed magnetic field for 1) 5 min, 2) 15 min, 3) 30 min, 4) 60 min and 5) 120 minutes. Cells without exposure (0 min) were used as the control group. For long-term effects, cells were cultured in osteogenic culture medium and divided into the following groups: exposure to the pulsed magnetic field for 6) 3 days, 7) 6 days and 8) 12 days. For each of groups 6-8, a separate control group was used.
Bone morphogenetic proteins (BMPs) have diverse functions in embryonic development and play crucial roles in osteogenesis. The BMP-Smad1/5/8 signaling pathway is important for osteogenic cell differentiation.
To study the mechanisms of action, cilia formation was prevented in cells via treatment with siRNA (small interfering RNA) to induce a gene knockdown (effect similar to knockout). Knockdown of bone morphogenetic proteins receptor II (BMPRII) was also conducted with the help of siRNA. Moreover, noggin, an antagonist of BMPs, and LDN-193189, an inhibitor of BMPRI kinases, were used.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 50 Hz
Modulation type: pulsed
ばく露時間: continuous for 5 minutes
ばく露2: 50 Hz
Modulation type: pulsed
ばく露時間: continuous for 15 minutes
ばく露3: 50 Hz
Modulation type: pulsed
ばく露時間: continuous for 30 minutes
ばく露4: 50 Hz
Modulation type: pulsed
ばく露時間: continuous for 60 minutes
ばく露5: 50 Hz
Modulation type: pulsed
ばく露時間: continuous for 120 minutes
ばく露6: 50 Hz
Modulation type: pulsed
ばく露時間: intermittent 60 minutes/day for 3 days
ばく露7: 50 Hz
Modulation type: pulsed
ばく露時間: intermittent 60 minutes/day for 6 days
ばく露8: 50 Hz
Modulation type: pulsed
ばく露時間: intermittent 60 minutes/day for 12 days

ばく露1

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • pulsed
ばく露時間 continuous for 5 minutes
Modulation
Modulation type pulsed
Duty cycle 50 %
ばく露装置
ばく露の発生源/構造
チャンバの詳細 60 mm culture dishes
ばく露装置の詳細 dishes were placed in an area with good uniformity within the coil; temperature was measured and overstepping of 37.5°C was signalized
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.6 mT - - - -

ばく露2

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • pulsed
ばく露時間 continuous for 15 minutes
Modulation
Modulation type pulsed
Duty cycle 50 %
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.6 mT - - - -

ばく露3

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • pulsed
ばく露時間 continuous for 30 minutes
Modulation
Modulation type pulsed
Duty cycle 50 %
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.6 mT - - - -

ばく露4

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • pulsed
ばく露時間 continuous for 60 minutes
Modulation
Modulation type pulsed
Duty cycle 50 %
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.6 mT - - - -

ばく露5

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • pulsed
ばく露時間 continuous for 120 minutes
Modulation
Modulation type pulsed
Duty cycle 50 %
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.6 mT - - - -

ばく露6

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • pulsed
ばく露時間 intermittent 60 minutes/day for 3 days
Modulation
Modulation type pulsed
Duty cycle 50 %
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.6 mT - - - -

ばく露7

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • pulsed
ばく露時間 intermittent 60 minutes/day for 6 days
Modulation
Modulation type pulsed
Duty cycle 50 %
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.6 mT - - - -

ばく露8

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • pulsed
ばく露時間 intermittent 60 minutes/day for 12 days
Modulation
Modulation type pulsed
Duty cycle 50 %
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.6 mT - - - -

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:
  • ばく露前
  • ばく露中
  • ばく露後

研究の主なアウトカム(著者による)

In cells with normal primary cilia formation, the protein expression of BMP2 and phosphorylated Smad1/5/8 was significantly increased in cells after 5 minutes of exposure (group 1) and peaked after 30 minutes of exposure (group 3) compared to the control group, indicating an activation of the BMP-Smad1/5/8 pathway. Furthermore, protein expression of BMP receptors BMPRII and BMPRIB was significantly increased after 15 minutes (group 2) and 120 minutes (group 5) compared to the control group, and receptors were localized at the bases of primary cilia.
Osteogenic differentiation and maturation of cells were significantly increased after 3, 6 and 12 days (groups 6-8) compared to the control groups. These promoting effects were negated by co-exposure with inhibitors LDN-193189 and noggin, confirming the BMP-Smad1/5/8 signal pathway in osteoblast differentiation and maturation.
Elimination of primary cilia via gene knockdown abolished the magnetic field-induced upregulation of BMPRII and its ciliary localization. Knockdown of BMPRII expression had no effects on primary cilia but significantly decreased the promoting effect of the magnetic field on osteoblastic differentiation and maturation.
The authors conclude that exposure to a 50 Hz pulsed magnetic field might stimulate osteogenic differentiation of rat osteoblasts by primary cilium-mediated upregulation of BMPRII expression and subsequently activation of the BMP-Smad1/5/8 signaling pathway.

研究の種別:

研究助成

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