IkappaBbetaは,炎症反応中に遺伝子発現を抑制し,活性化するように作用します
Ping Rao1, Mathew S Hayden, Meixiao Long
1Department of Immunobiology and Department of Molecular Biophysics & Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
Nature
|August 27, 2010
まとめ
カッパBベータの阻害剤 (IkappaBbeta) は,炎症において二重の役割を果たしています. その分解は炎症性遺伝子発現を促進しますが,その核形態は腫瘍死滅因子アルファ (TNF-alpha) の生成を延長し,治療標的を提供します.
科学分野:
- 免疫学 免疫学とは
- 分子生物学は分子生物学である.
- セルラー・シグナリング
背景:
- 核因子-kappaB (NF-kappaB) の活性化は,炎症性遺伝子発現を誘発する.
- イカッパベータを含むカッパB (IkappaB) タンパク質の阻害剤は,NF-カッパBの局所化を調節する.
- 炎症反応におけるイカッパベータの正確なインビボ機能は,まだ完全に理解されていません.
研究 の 目的:
- 炎症反応中のイカッパベータの生物学的役割を明らかにする.
- イカッパベータがNF-kappaBの標的遺伝子発現,特にTNF-alphaに影響するメカニズムを調査する.
- 炎症性疾患におけるイカッパベータを標的とした治療の可能性を評価する.
主な方法:
- イカッパベータ欠乏症 (イカッパベータ ((-/-)) のマウスの生成と分析.
- 炎症反応を誘発するリポポリサッカリド (LPS) 刺激.
- NF-kappaBの活性化,TNF-α mRNAの発現,およびタンパク質レベルの定量分析.
- クロマチン免疫降水 (ChIP) 測定は,標的遺伝子プロモーターの核NF-kappaB:IkappaBbeta複合体を検出する.
主要な成果:
- IkappaBbetaの分解により,NF-kappaBジマーが放出され,TNF-alpha.のような炎症性遺伝子を上調する.
- イカッパベータの欠如は,正常なNF-kappaBの活性化にもかかわらず,逆説的にTNF-αの発現を著しく低下させた.
- 核,低酸化イカッパベータはp65:c-Relヘテロダイマーと複合体を形成し,TNF-αプロモーターと結合し,長時間TNF-α発現を維持する.
- IkappaBbeta (((-/-) マウスは,LPS誘発性 септикショックとコラーゲン誘発性関節炎に対する抵抗性を示した.
結論:
- イカッパベータは,炎症反応を阻害し,促進するという二重の機能を発揮する.
- 核イカッパベータは,p65:c-Relヘテロダイマー経由で持続的なTNF-α生成に不可欠です.
- IkappaBbetaを標的にすることは,炎症状態における慢性TNF-α生成を選択的に抑制するための潜在的な戦略を示しています.
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