c-Junは,肺動脈の滑らかな筋肉細胞の電圧ゲートされたK (((+)) チャンネル活動を低下させます
1Department of Medicine, University of California, San Diego, San Diego, CA 92103-8382, USA.
Circulation
|September 26, 2001
まとめ
転写因子c-Junは,肺動脈の滑らかな筋肉細胞 (PASMCs) の電圧誘導カリウムチャンネル (K(v)) 活動を減少させます. このK ((v)) 流の減少は,膜の去極化,カルシウムの増加,およびPASMCの増殖を促進します.
科学分野:
- 分子生物学は分子生物学である.
- 心血管生理学 心血管の生理学
- 細胞生物学 細胞生物学
背景:
- 電圧誘導のカリウム (K) チャンネルは膜ポテンシャル (E) を調節し,シトソリックフリーCa2+濃度 ([Ca2+]cyt) に影響を及ぼします.
- 肺動脈の滑らかな筋肉細胞 (PASMCs) の[Ca2+][Cyt]が上昇すると,血管収縮と増殖が促進されます.
- 増殖を刺激する転写因子であるc-Junが,PASMCにおけるK ((v)) チャンネル活性を調節する役割は,以前は不明でした.
研究 の 目的:
- PASMCのK (v) チャンネル活動に対するc-Junの影響を調査する.
- c-Junが膜ポテンシャルとPASMCの増殖に与える影響を決定する.
主な方法:
- アデノウイルスベクターは,初次培養のPASMCsでc-Junを過剰表現するために使用されました.
- K(v) の電流 (I(K(V))) は電気生理学を用いて測定された.
- 単細胞RT-PCRでKv1.5mRNAレベルが評価され, [3H]チミジンの組み込みにより増殖が測定されました.
主要な成果:
- c-Junの過剰発現は,PASMCのK ((v)) 流とKv1.5mRNAレベルを低下させた.
- c-JunはKvbeta(2) のタンパク質発現を上限調節し,I(K(V)) の不活性化を加速した.
- c-Junを過剰に発現したPASMCsは,膜脱極化と増殖を示した.
結論:
- c-Jun媒介のPASMC増殖は,K (((v) チャンネル活性が低下している.
- 減少したK (v) 流は,膜の去極化を引き起こし,[Ca (−2+) ] (−cyt) を上昇させます.
- このメカニズムはPASMCの成長を促進し,肺高血圧におけるc-Junの役割を示唆しています.
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