ホスホジエステラーゼIII阻害薬の細胞保護作用
北海道大学大学院医学研究科
救急医学分野
松田直之
はじめに
現在11種類が同定されているcyclic nucleotide phosphadiesterase（PDE）は，その各々が様々な細胞でMn2+存在下にcAMPとcGMPを加水分解し，プロテインキナーゼA（PKA）とプロテインキナーゼG（PKG）の活性を制御している。循環管理で使用されるPDE3阻害薬の目的はcAMP分解を抑制し心筋細胞の陽性変力作用を高めることにあるが，近年，心臓，血管，肝臓，腎臓，腸管などの様々な臓器でPDE3阻害薬の細胞保護作用が示唆されている1-4)。本稿ではPDE3阻害薬の細胞保護作用を論じる。
PDE3阻害薬の現在
PDE3はmRNA合成過程のスプライシングによりPDE3AとPDE3Bの2つのファミリーに分類される5, 6)。PDE3Aは心臓，血管平滑筋，血小板に高濃度で存在し7)，一方，PDE3Bは肝臓，脂肪組織，膵臓に分布し，ジヒドロピリダジノン8)のようなPDE3B選択的阻害薬の肝細胞保護作用やインスリン機能改善作用が期待されている。このように少なくとも2種類のファミリーに分類されているPDE3は，蛋白レベルではPDE3A1（136 kDa），PDE3A2（118 kDaおよび94 kDa），PDE3B（123 kDa）などのいくつかの細かな表現型が存在し，さらに小胞体レベルではN末端に翻訳後修飾を受け，細胞内輸送が決定されている。正常な心筋細胞ではPDE3の多くは筋小胞体膜に存在するが，一部はゴルジ体のエンドソーム9）や核10)に分布する。このPDE3の細胞内局在は，全身性炎症や小胞体ストレスにより変化している可能性があり，今後，様々な病態で検討するべき課題である。
現在日本で臨床使用されているPDE3阻害薬は，ミルリノン，オルプリノン，アムリノン，そして，カルシウム感受性増強作用を合わせて持つピモベンダンである。多くのPDE3阻害薬はPDE3阻害薬作用を10-7-10-5 mol/ L（M）で高めるのに対して，10-5M以上の濃度よりPDE4とPDE5の阻害作用が出現する11)。PDE4阻害により抗炎症効果が得られるため12, 13)，10-5Mレベル以上の高濃度のPDE3阻害薬では確実に抗炎症作用が期待できる。このようにPDE3阻害薬の細胞保護作用の検討に当たっては，作用するPDEサブタイプと投与濃度の評価を加えることも大切である。
PDE3阻害薬と心臓保護作用
心臓におけるPDE3の作用はcAMPのみならずcGMPの加水分解にある。その解離定数はKm cAMP=0.2 μM，Km cGMP=0.1 μMと大差がないが，cAMPの分解速度はcGMPに対して約10倍早いため，PDE3阻害は陽性変力作用に働く7)。このように心筋細胞ではcAMPが有意に高まるが，cAMPとcGMPの産生バランスにより陽性変力作用が制御されていることには留意が必要である。産生されたcGMPは，0.5 μMレベルの低濃度ではPDE3を抑制しcAMP産生を高めるが，5 μMレベル以上の高濃度ではcAMPレベルを低下させる2相性の作用を持つ14)。また，NOドナーの投与により細胞内cGMP濃度が高められている場合は，PDE3阻害薬がより強く心抑制に働く。細胞内cGMP濃度に依存的してL型Ca2+チャネル電流も抑制されるため，PDE3阻害薬の投与を過剰にした場合，細胞内cGMP濃度が高まることで細胞内Ca2+過負荷が軽減されるように，cGMPが自己制御的に働く14)。
さて，虚血心筋では細胞内Ca2+過負荷が生じるが，この虚血耐性にはミトコンドリア機能が重要である15)。これまで虚血耐性を導くミトコンドリアにはKATPチャネルの開口が必要と考えられてきたが，これに加えて，PKA活性に依存して開口するlarge conductance Ca2+ activated K+チャネル（BKCa）がミトコンドリア内膜に存在し，虚血耐性に関与することが確認された16)。PDE3阻害薬をはじめとするPKA活性化物質は虚血心筋でp38 MAPK活性により細胞保護をもたらすことが知られていたが17)，その一方で，cAMP，PKA依存性BKCa開口によるミトコンドリア内膜の過分極を介してミトコンドリアへのCa2+取り込みを抑制し，ミトコンドリア機能を維持させる可能性がある16)。虚血状態のミトコンドリアからは活性酸素が放出されるため，活性酸素放出に伴う心筋細胞のアポトーシスが進行するが，PDE3阻害薬などのPKA活性化物質がミトコンドリア保護を介してアポトーシスを抑制する可能性が示唆された。これは心筋細胞において，PKA活性化に伴う細胞内Ca2+過負荷をミトコンドリアレベルに持ち込まないようにする自己防御作用かもしれないが，心筋細胞に限らず，様々な細胞のミトコンドリアに共通するPKAの作用かもしれない。
PDE3阻害薬と血管保護作用
心筋細胞と同様に血管にはPDE3とPDE4が存在するが，PDE3は血管平滑筋細胞に多く，PDE4は血管内皮細胞にも血管平滑筋にも存在する。アドレナリンβ受容体刺激を併用している場合，PDE3阻害薬は血管平滑筋でもcAMP産生を過剰に高め，PKA活性に依存して血管弛緩作用が強まる11)。NOドナーとの併用では強い血管拡張が惹起されるが，これは血管平滑筋でのcGMP産生が高まり，細胞内Ca2+流入が抑制されるためである11)。
細胞保護作用が期待される炎症病態の血管内皮細胞では，Toll-like受容体やtumor necrosis factor-α，interleukin-1βなどの様々な炎症性受容体刺激により，nuclear factor- κB（NF-κB）などの転写因子が活性化され，結果的に，血管内皮細胞障害が進行する18)。このような病態で血管内皮細胞機能を維持するために，特に重要な役割を担うのがAktである15)。AktはAKT8と呼ばれるレトロウイルス由来の癌遺伝子v-aktに対応する癌原遺伝子より命名され，その構造がPKAなどに類似するため，プロテインキナーゼB（PKB）と呼ばれるセリン・スレオニンキナーゼである。敗血症血管ではAkt活性が一過性に増加するものの，敗血症の進行により活性が減少する傾向があり，リン酸化されたAktの作用であるアポトーシス抑制，eNOS活性，糖代謝改善，蛋白合成などの作用が損なわれる。我々のウサギ敗血症動物を用いた基礎実験系において19, 20)，PDE3阻害薬オルプリノンは肺動脈や腸間膜動脈におけるAktのリン酸化を改善させ，血管内皮細胞を保護することを確認した（Figure参照）。
今回報告された池田らによる研究は，オルプリノンが活性酸素を直接的に消去する可能性を示すものである21)。既に2002年にヒト臍帯静脈血管内皮細胞でリポポリサッカライドにより誘発されるアポトーシスをPDE3阻害薬シロスタゾールが抑制することが示されている22)。シロスタゾールはヒドロキシラジカルをIC50 2.58±0.07 μMレベルで消去し，活性酸素で惹起される血管内皮細胞のアポトーシスを抑制している22)。オルプリノンにおいても同様な活性酸素消去能が確認されたことは貴重であり21)，オルプリノンはIC50 6.10±0.44 μMのPDE4阻害作用を高めない濃度でヒドロキシラジカルを直接的に除去する可能性がある。虚血再灌流障害15），重症敗血症18)，熱傷23)，放射線障害24)などに合併する細胞障害やアポトーシスの進行には活性酸素が重要な役割を担う。池田らによる報告21)はex vivoの研究であるため，アポトーシスなどの機能評価ができないものの，PDE3阻害薬の細胞保護作用にヒドロキシラジカル直接消去という新たな一面を追加した。このようにオルプリノンをはじめとするPDE3阻害薬は，活性酸素直接消去，ミトコンドリア保護，Akt活性化などにより細胞保護に働く可能性があり，今後の更なる検討と臨床応用が期待される。
結 語
循環作動物質PDE3阻害薬の新たな側面として，血管内皮細胞保護や臓器保護が期待される。この作用は末梢循環改善以外の機序により惹起される可能性がある。PDE3阻害薬により，虚血や炎症病態で導かれる活性酸素の除去，ミトコンドリア機能維持，Akt活性化などを介して，細胞機能が維持されうる。PDE3は主要臓器のどの細胞のどこで何をしているのか，細胞保護作用という新たなPDE3阻害薬の可能性に期待している。
文 献
1）Satoh T, Morisaki H, Ai K, et al. Olprinone, a phosphodiesterase III inhibitor, reduces gut mucosal injury and portal endotoxin level during acute hypoxia in rabbits. Anesthesiology. 2003;98:1407-14.
2）Nagata E, Kakihana Y, Tobo K, et al. The effects of olprinone (a phosphodiesterase III inhibitor) on hepatic vascular bed in a porcine model of endotoxemia. Anesth Analg. 2001;92:676-80.
3）Mizutani A, Murakami K, Okajima K, et al. Olprinone reduces ischemia/reperfusion-induced acute renal injury in rats through enhancement of cAMP. Shock. 2005;24:281-7.
4）Mikawa K, Akamatsu H, Nishina K, et al. The effect of phosphodiesterase III inhibitors on human neutrophil function. Crit Care Med. 2000;28:1001-5.
5）Wechsler J, Choi YH, Krall J, et al. Isoforms of cyclic nucleotide phosphodiesterase PDE3A in cardiac myocytes. J Biol Chem. 2002;277:38072-8.
6）Miki T, Taira M, Hockman S, et al. Characterization of the cDNA and gene encoding human PDE3B, the cGIP1 isoform of the human cyclic GMP-inhibited cyclic nucleotide phosphodiesterase family. Genomics. 1996;36:476-85.
7）Beavo JA. Cyclic nucleotide phosphodiesterases: functional implications of multiple isoforms.
Physiol Rev. 1995;75:725-48.
8）Edmondson SD, Mastracchio A, He J, et al. Benzyl vinylogous amide substituted aryldihydropyridazinones and aryldimethylpyrazolones as potent and selective PDE3B inhibitors. Bioorg Med Chem Lett. 2003;13:3983-7.
9）Geoffroy V, Fouque F, Lugnier C, et al. Characterization of an in vivo hormonally regulated phosphodiesterase 3 (PDE3) associated with a liver Golgi-endosomal fraction. Arch Biochem Biophys. 2001;387:154-62.
10）Lugnier C, Keravis T, Le Bec A, et al. Characterization of cyclic nucleotide phosphodiesterase isoforms associated to isolated cardiac nuclei. Biochim Biophys Acta. 1999;1472:431-46.
11）Lugnier C, Komas N. Modulation of vascular cyclic nucleotide phosphodiesterases by cyclic GMP: role in vasodilatation. Eur Heart J. 1993;14:141-8.
12）Mata M, Sarria B, Buenestado A, et al. Phosphodiesterase 4 inhibition decreases MUC5AC expression induced by epidermal growth factor in human airway epithelial cells. Thorax. 2005;60:144-52.
13）Toward TJ, Johnson FJ, Boult JE, et al. Airway function and reactivity, leukocyte influx and nitric oxide after inoculation with parainfluenza-3 virus: effects of dexamethasone or rolipram. Int Immunopharmacol. 2005;5:771-82.
14）Vandecasteele G, Verde I, Rucker-Martin C, et al. Cyclic GMP regulation of the L-type Ca2+ channel current in human atrial myocytes. J Physiol. 2001 Jun 1;533(Pt 2):329-40.
15）松田直之. 2003年心血管系基礎研究の動向―Ischemic preconditioningと血管内皮保護の戦略―. Cardiovascular Anesthesia 2004; 8: 61-7.
16）Sato T, Saito T, Saegusa N, et al. Mitochondrial Ca2+-activated K+ channels in cardiac myocytes: a mechanism of the cardioprotective effect and modulation by protein kinase A. Circulation. 2005;111:198-203.
17） Sanada S, Kitakaze M, Papst PJ, et al. Cardioprotective effect afforded by transient exposure to phosphodiesterase III inhibitors: the role of protein kinase A and p38 mitogen-activated protein kinase. Circulation. 2001;104:705-10.
18） 松田直之. 全身性炎症反応症候群とToll-like受容体シグナル -Alert Cell Strategy-. 循環制御 2004; 25: 276-84.
19）Matsuda N, Hattori Y, Akaishi Y, et al. Impairment of cardiac β-adrenoceptor cellular signaling by decreased expression of Gsα in septic rabbits. Anesthesiology 2000; 93:1465-73.
20）Matsuda N, Hattori Y, Zhang XH, et al. Contractions to histamine in pulmonary and mesenteric arteries from endotoxemic rabbits: modulation by vascular expressions of inducible nitric oxide synthase and histamine H1-receptors. J Pharmacol Exp Ther 2003; 307:175-81.
21）池田幸穂，李昌一，吉野文彦，他. ホスホジエステラーゼⅢ阻害薬・塩酸オルプリノンの直接的活性酸素消去能. 日集中医誌2006
22）Kim KY, Shin HK, Choi JM, et al. Inhibition of lipopolysaccharide-induced apoptosis by cilostazol in human umbilical vein endothelial cells. J Pharmacol Exp Ther. 2002;300:709-15.
23）Horton JW. Free radicals and lipid peroxidation mediated injury in burn trauma: the role of antioxidant therapy. Toxicology. 2003;189:75-88.
24） Zhang XH, Matsuda N, Jesmin S, et al. Normalization by edaravone a free radical scavenger of irraiation-reduced endothelial nitric oxide synthase expression. Eur J Pharmacol. 2003; 476:131-7.
深在性真菌症 ～SFI Forum～
誌上ディベート 竹末芳生 vs 松田直之
「Candida glabrataは問題となっている」の立場から
松田直之
はじめに
北海道大学病院救急部・集中治療部（ICU）では週2回の監視培養検査を行っているが，Candida属は第1位の検出菌株であり，管理の長期化した重症患者より検出されることが多い。このCandida属の中でCandida grabrataはCandida albicansのようなgerm tube形成を起こさないことから繁殖性が弱いと考えられているが，敗血症を惹起する場合がある。特に免疫抑制状態や外科術後長期管理中の患者から検出されたCandida grabrataは(1→3)-β-D-glucanの著明な上昇を認め，発熱やC反応性蛋白（CRP）の上昇を伴う場合がある。本稿では「Candida glabrataは問題となっている」の立場から，Candida glabrata感染症を考える。
ICUにおける深在性カンジダ症
当院ICUにおけるCandida属の検出は2003年，2004年ともに第1位であり，2005年も検出数が高く推移していた1）（表1参照）。このうちCandida grabrataは，Candida albicansに次ぐ第2位であり，創部，喀痰，胃液，便，尿などの多岐にわたる検体より検出され，(1→3)-β-D-glucanの上昇を伴い，炎症を惹起していると考えられるケースも多い（表2参照）。Candida grabrataが起炎菌として作用する背景として，多発外傷，移植術後，血液疾患，広範囲熱傷などの免疫低下をきたしやすい病態を当部が管理していることが挙げられる2）。2004年から2005年の2年間にCandida grabrataが血液中より検出された患者は当院全体で3名だったが，このうち2名に炎症を認め，抗真菌薬の投与でCRPの低下を得ている。当院ICUにおいてはここ数年間Candida grabrataの血中検出を認めないが，局所でCandida grabrataが繁殖し全身性炎症を惹起したと考えられる例は比較的多い。
汎発性腹膜炎の一因となったCandida grabrata感染症の一例
Candida grabrata敗血症の一例を提示する。86歳女性がS状結腸瘻より汎発性腹膜炎となり，術後管理をされていた。腹腔内膿瘍の一因としてCandida grabrataが同定されていた。Candida grabrataは，その後，血液からも検出され，(1→3)-β-D-glucanの血中濃度が108 pg/mL（基準値：0-10.9 pg/mL）と高値を示した。CRPは9.19 mg/dLと上昇し，38度代の高熱とショックを認め，呼吸管理とドパミンによる循環管理，フルコナゾールの投与が行われた。これらの10日間の管理により，血液のCandida grabrataは消失し，CRPが5.75 mg/dLまで低下したが，(1→3)-β-D-glucanは依然50 pg/mLレベルで推移し，フルコナゾールの投与が継続されたにもかかわらず，敗血症治療に難渋する結果となった。本症例においては，Staphylococcus epiderumidisを同時に検出しており，ミノマイシンが併用されていたが，他のCandida属の検出はなく，(1→3)-β-D-glucan低下とCRP低下の推移が一致していたことより，Candida grabrataが敗血症の主要因となったと評価された。
本症例のCandida grabrata株の抗真菌薬に対するminimum inhibitory concentration （MIC90）を調べた結果，フルコナゾールとミコナゾールは8 μg/mL，ミカファンギンとアンフォテンシンBが1 μg/mLだった。従来，Candida grabrataはフルコナゾールなどのアゾール系抗真菌薬の感受性が低いとされているが2），当院のデータにおいてもCandida grabrataに対するフルコナゾールの感受性が低下している。このようにCandida grabrataが繁殖した際には敗血症の起炎菌となる可能性があり，抗真菌薬での治療を行うならば，感受性を評価するべきであり，盲目的にフルコナゾールを使うのは望ましくないと評価された。
動物モデルにおける検証
当院で検出されたCandida grabrataを用いて，マウスにおける急性肺障害の進行を評価したので追記する。急性肺障害は全身性炎症反応症候群に合併しやすいが，肺や気管にはToll-like受容体（TLR）やtumor necrosis factor受容体などの炎症性受容体が比較的豊富に存在するため，これらのリガンドを経気道的に投与しても炎症やアポトーシスが進行する3-5）。急性肺障害が進行する際には，転写因子nuclear factor-κB（NF-κB）の活性化が関与し，誘導型NO合成酵素，プロスタグランジン，ケモカイン，接着分子，組織因子などの発現が高まる3, 6）。
エーテル麻酔下に18週齡のBALB-cAJclマウスの気管を剖出し，生理的食塩水0.5 mLに撹拌させたCandida grabrataを緩徐に26G針で経気管投与した。対照群は生理的食塩水のみの緩徐な投与とした。マウスはこの暴露の10分以内に元気に動き始めたが，Candida grabrataが投与されたマウスは動作が緩慢であり，振るえが強かった。暴露10時間後に同じ麻酔で全肺葉を取り出し，全蛋白と，その一部より核タンパクを抽出し，NF-κBファミリーの1つであるp65のウエスタンブロッド解析を，抗p65抗体（Santa Cruz Biotechnology）で施行した。研究の詳細はこれまでの方法に準じた3, 6）。結果はCandida grabrata投与によりp65の核移行が約9倍レベルに高まるものとなった（図参照）。この結果より，Candida grabrataが肺で新たに検出された場合は，少なくとも肺局所において十分に炎症を惹起できる可能性があると評価した6）。
Candida grabrata局所感染により全身性炎症は惹起されうる
Candida grabrataに罹患した場合，Weinbergerなどの報告ではショックを呈したものが30.8 ％，30日以内の死亡率は38.5 %であり7），Almiranteなどの報告では7日以内の死亡率が31 %，最終死亡率が50 %だった8）。Candida grabrata は高齢者や免疫低下患者では十分に全身性炎症のトリガーとなると評価されている7, 8）。ショックや多臓器不全の多くは，起炎菌が血中に存在することはなく，局所で過剰産生される炎症性サイトカインにより全身性炎症反応症候群の一環として惹起される3）。Candida grabrata の菌体成分であるβ-glucanなどが血中に移行することで，TLR4）やDectin-15）などの受容体を介して，他の主要臓器や血管内皮細胞で炎症を惹起する可能性にも留意しなければならない。また，抗菌薬の静脈内投与や中心静脈栄養によりCandida grabrataの腸での定着が生じやすい可能性も示唆されている7-9）。外科術後や重症患者管理においては絶食などによる腸管免疫の低下により，腸でCandida grabrataが増殖し起炎菌として作用する可能性もある。さらには，Candida属は好中球やマクロファージにより貪食や殺菌を受けるが10, 11），この作用が急性肺障害で用いる好中球エステラーゼ阻害薬やステロイドにより低下し，深在性真菌症が進展しやすい可能性もある。このようにCandida grabrataが血中に存在しなくとも，局所で静かにCandida grabrata感染が増悪し，ある瞬間に多臓器不全に進展する危険が存在するのだ。Candida grabrata感染症が出現する背景として，特にCandida grabrataの MICの高いフルコナゾールの使用にも問題がある。当院では表3のようにフルコナゾールの感受性は残念ながらCandida属のすべてにおいて低下している。抗真菌薬の使用に際しても，抗菌薬と同様に，耐性化傾向を十分に把握し，適切な選択を模索する必要があろう1）。
結 語
免疫の低下した重症患者などでは， Candida grabrataは十分に起炎菌となる。局所におけるCandida grabrataの検出においては，炎症所見と(1→3)-β-D-glucan値の推移を評価することが大切であり，抗真菌薬の適切な投与を念頭に入れるべきである。Candida grabrataが増殖し，β-glucanが上昇した場合，TLRやDectin-1などを介して，主要臓器や血管内皮細胞で炎症性サイトカインが過剰産生される。Candida grabrataが血中に存在しなくとも，局所感染により多臓器不全が進展する可能性がある。フルコナゾールの使用によりCandida grabrataが蔓延する可能性にも十分に留意する必要があり，抗真菌薬のMICを定期的に評価して，有効なものをバランスよく使用する工夫が必要である。
文 献
1）松田直之，秋沢宏次，南須原康行 他：ICUにおける抗菌薬サイクリング. Progress in Medicine, 25:2329-2336, 2005
2）Alexander BD, Schell WA, Miller JL, et al: Candida glabrata fungemia in transplant patients receiving voriconazole after fluconazole. Transplantation 80:868-871, 2005
3）松田直之： 総説: 全身性炎症反応症候群とToll-like受容体シグナル -Alert Cell Strategy-. 循環制御 25: 276-284, 2004
4）Blasi E, Mucci A, Neglia R, et al: Biological importance of the two Toll-like receptors, TLR2 and TLR4, in macrophage response to infection with Candida albicans. FEMS Immunol Med Microbiol 44:69-79, 2005
5）Brown GD, Herre J, Williams DL, et al: Dectin-1 mediates the biological effects of beta-glucans. J Exp Med 197:1119-1124, 2003
6）Matsuda N, Hattori Y, Takahashi Y, et al: Nuclear Factor-κB decoy oligonucleotides prevent acute lung injury in mice with cecal ligation and puncture-induced sepsis. Mol Pharmacol 67:1018-1025, 2005
7）Weinberger M, Leibovici L, Perez S, et al: Characteristics of candidaemia with Candida albicans compared with non-albicans Candida species and predictors of mortality. J Hosp Infect 61:146-154, 2005
8）Almirante B, Rodriguez D, Park BJ, et al: Barcelona Candidemia Project Study Group. Epidemiology and predictors of mortality in cases of Candida bloodstream infection: results from population-based surveillance, barcelona, Spain, from 2002 to 2003. J Clin Microbiol 43:1829-1835, 2005
9）Pultz NJ, Stiefel U, Ghannoum M, et al: Effect of parenteral antibiotic administration on establishment of intestinal colonization by Candida glabrata in adult mice. Antimicrob Agents Chemother 49:438-440, 2005
10）Kullberg BJ, Netea MG, Vonk AG, et al: Modulation of neutrophil function in host defense against disseminated Candida albicans infection in mice. FEMS Immunol Med Microbiol 26: 299–307, 1999
11）Maródi L, Korchak HM, Johnston RB: Mechanisms of host defense against Candida species. 1. Phagocytosis by monocytes and monocyte-derived macrophages. J Immunol 146: 2783–2789, 1991
誌上ディベート 竹末芳生 vs 松田直之
「Candida glabrataは問題となっている」の立場から
松田直之
はじめに
北海道大学病院救急部・集中治療部（ICU）では週2回の監視培養検査を行っているが，Candida属は第1位の検出菌株であり，管理の長期化した重症患者より検出されることが多い。このCandida属の中でCandida grabrataはCandida albicansのようなgerm tube形成を起こさないことから繁殖性が弱いと考えられているが，敗血症を惹起する場合がある。特に免疫抑制状態や外科術後長期管理中の患者から検出されたCandida grabrataは(1→3)-β-D-glucanの著明な上昇を認め，発熱やC反応性蛋白（CRP）の上昇を伴う場合がある。本稿では「Candida glabrataは問題となっている」の立場から，Candida glabrata感染症を考える。
ICUにおける深在性カンジダ症
当院ICUにおけるCandida属の検出は2003年，2004年ともに第1位であり，2005年も検出数が高く推移していた1）（表1参照）。このうちCandida grabrataは，Candida albicansに次ぐ第2位であり，創部，喀痰，胃液，便，尿などの多岐にわたる検体より検出され，(1→3)-β-D-glucanの上昇を伴い，炎症を惹起していると考えられるケースも多い（表2参照）。Candida grabrataが起炎菌として作用する背景として，多発外傷，移植術後，血液疾患，広範囲熱傷などの免疫低下をきたしやすい病態を当部が管理していることが挙げられる2）。2004年から2005年の2年間にCandida grabrataが血液中より検出された患者は当院全体で3名だったが，このうち2名に炎症を認め，抗真菌薬の投与でCRPの低下を得ている。当院ICUにおいてはここ数年間Candida grabrataの血中検出を認めないが，局所でCandida grabrataが繁殖し全身性炎症を惹起したと考えられる例は比較的多い。
汎発性腹膜炎の一因となったCandida grabrata感染症の一例
Candida grabrata敗血症の一例を提示する。86歳女性がS状結腸瘻より汎発性腹膜炎となり，術後管理をされていた。腹腔内膿瘍の一因としてCandida grabrataが同定されていた。Candida grabrataは，その後，血液からも検出され，(1→3)-β-D-glucanの血中濃度が108 pg/mL（基準値：0-10.9 pg/mL）と高値を示した。CRPは9.19 mg/dLと上昇し，38度代の高熱とショックを認め，呼吸管理とドパミンによる循環管理，フルコナゾールの投与が行われた。これらの10日間の管理により，血液のCandida grabrataは消失し，CRPが5.75 mg/dLまで低下したが，(1→3)-β-D-glucanは依然50 pg/mLレベルで推移し，フルコナゾールの投与が継続されたにもかかわらず，敗血症治療に難渋する結果となった。本症例においては，Staphylococcus epiderumidisを同時に検出しており，ミノマイシンが併用されていたが，他のCandida属の検出はなく，(1→3)-β-D-glucan低下とCRP低下の推移が一致していたことより，Candida grabrataが敗血症の主要因となったと評価された。
本症例のCandida grabrata株の抗真菌薬に対するminimum inhibitory concentration （MIC90）を調べた結果，フルコナゾールとミコナゾールは8 μg/mL，ミカファンギンとアンフォテンシンBが1 μg/mLだった。従来，Candida grabrataはフルコナゾールなどのアゾール系抗真菌薬の感受性が低いとされているが2），当院のデータにおいてもCandida grabrataに対するフルコナゾールの感受性が低下している。このようにCandida grabrataが繁殖した際には敗血症の起炎菌となる可能性があり，抗真菌薬での治療を行うならば，感受性を評価するべきであり，盲目的にフルコナゾールを使うのは望ましくないと評価された。
動物モデルにおける検証
当院で検出されたCandida grabrataを用いて，マウスにおける急性肺障害の進行を評価したので追記する。急性肺障害は全身性炎症反応症候群に合併しやすいが，肺や気管にはToll-like受容体（TLR）やtumor necrosis factor受容体などの炎症性受容体が比較的豊富に存在するため，これらのリガンドを経気道的に投与しても炎症やアポトーシスが進行する3-5）。急性肺障害が進行する際には，転写因子nuclear factor-κB（NF-κB）の活性化が関与し，誘導型NO合成酵素，プロスタグランジン，ケモカイン，接着分子，組織因子などの発現が高まる3, 6）。
エーテル麻酔下に18週齡のBALB-cAJclマウスの気管を剖出し，生理的食塩水0.5 mLに撹拌させたCandida grabrataを緩徐に26G針で経気管投与した。対照群は生理的食塩水のみの緩徐な投与とした。マウスはこの暴露の10分以内に元気に動き始めたが，Candida grabrataが投与されたマウスは動作が緩慢であり，振るえが強かった。暴露10時間後に同じ麻酔で全肺葉を取り出し，全蛋白と，その一部より核タンパクを抽出し，NF-κBファミリーの1つであるp65のウエスタンブロッド解析を，抗p65抗体（Santa Cruz Biotechnology）で施行した。研究の詳細はこれまでの方法に準じた3, 6）。結果はCandida grabrata投与によりp65の核移行が約9倍レベルに高まるものとなった（図参照）。この結果より，Candida grabrataが肺で新たに検出された場合は，少なくとも肺局所において十分に炎症を惹起できる可能性があると評価した6）。
Candida grabrata局所感染により全身性炎症は惹起されうる
Candida grabrataに罹患した場合，Weinbergerなどの報告ではショックを呈したものが30.8 ％，30日以内の死亡率は38.5 %であり7），Almiranteなどの報告では7日以内の死亡率が31 %，最終死亡率が50 %だった8）。Candida grabrata は高齢者や免疫低下患者では十分に全身性炎症のトリガーとなると評価されている7, 8）。ショックや多臓器不全の多くは，起炎菌が血中に存在することはなく，局所で過剰産生される炎症性サイトカインにより全身性炎症反応症候群の一環として惹起される3）。Candida grabrata の菌体成分であるβ-glucanなどが血中に移行することで，TLR4）やDectin-15）などの受容体を介して，他の主要臓器や血管内皮細胞で炎症を惹起する可能性にも留意しなければならない。また，抗菌薬の静脈内投与や中心静脈栄養によりCandida grabrataの腸での定着が生じやすい可能性も示唆されている7-9）。外科術後や重症患者管理においては絶食などによる腸管免疫の低下により，腸でCandida grabrataが増殖し起炎菌として作用する可能性もある。さらには，Candida属は好中球やマクロファージにより貪食や殺菌を受けるが10, 11），この作用が急性肺障害で用いる好中球エステラーゼ阻害薬やステロイドにより低下し，深在性真菌症が進展しやすい可能性もある。このようにCandida grabrataが血中に存在しなくとも，局所で静かにCandida grabrata感染が増悪し，ある瞬間に多臓器不全に進展する危険が存在するのだ。Candida grabrata感染症が出現する背景として，特にCandida grabrataの MICの高いフルコナゾールの使用にも問題がある。当院では表3のようにフルコナゾールの感受性は残念ながらCandida属のすべてにおいて低下している。抗真菌薬の使用に際しても，抗菌薬と同様に，耐性化傾向を十分に把握し，適切な選択を模索する必要があろう1）。
結 語
免疫の低下した重症患者などでは， Candida grabrataは十分に起炎菌となる。局所におけるCandida grabrataの検出においては，炎症所見と(1→3)-β-D-glucan値の推移を評価することが大切であり，抗真菌薬の適切な投与を念頭に入れるべきである。Candida grabrataが増殖し，β-glucanが上昇した場合，TLRやDectin-1などを介して，主要臓器や血管内皮細胞で炎症性サイトカインが過剰産生される。Candida grabrataが血中に存在しなくとも，局所感染により多臓器不全が進展する可能性がある。フルコナゾールの使用によりCandida grabrataが蔓延する可能性にも十分に留意する必要があり，抗真菌薬のMICを定期的に評価して，有効なものをバランスよく使用する工夫が必要である。
文 献
1）松田直之，秋沢宏次，南須原康行 他：ICUにおける抗菌薬サイクリング. Progress in Medicine, 25:2329-2336, 2005
2）Alexander BD, Schell WA, Miller JL, et al: Candida glabrata fungemia in transplant patients receiving voriconazole after fluconazole. Transplantation 80:868-871, 2005
3）松田直之： 総説: 全身性炎症反応症候群とToll-like受容体シグナル -Alert Cell Strategy-. 循環制御 25: 276-284, 2004
4）Blasi E, Mucci A, Neglia R, et al: Biological importance of the two Toll-like receptors, TLR2 and TLR4, in macrophage response to infection with Candida albicans. FEMS Immunol Med Microbiol 44:69-79, 2005
5）Brown GD, Herre J, Williams DL, et al: Dectin-1 mediates the biological effects of beta-glucans. J Exp Med 197:1119-1124, 2003
6）Matsuda N, Hattori Y, Takahashi Y, et al: Nuclear Factor-κB decoy oligonucleotides prevent acute lung injury in mice with cecal ligation and puncture-induced sepsis. Mol Pharmacol 67:1018-1025, 2005
7）Weinberger M, Leibovici L, Perez S, et al: Characteristics of candidaemia with Candida albicans compared with non-albicans Candida species and predictors of mortality. J Hosp Infect 61:146-154, 2005
8）Almirante B, Rodriguez D, Park BJ, et al: Barcelona Candidemia Project Study Group. Epidemiology and predictors of mortality in cases of Candida bloodstream infection: results from population-based surveillance, barcelona, Spain, from 2002 to 2003. J Clin Microbiol 43:1829-1835, 2005
9）Pultz NJ, Stiefel U, Ghannoum M, et al: Effect of parenteral antibiotic administration on establishment of intestinal colonization by Candida glabrata in adult mice. Antimicrob Agents Chemother 49:438-440, 2005
10）Kullberg BJ, Netea MG, Vonk AG, et al: Modulation of neutrophil function in host defense against disseminated Candida albicans infection in mice. FEMS Immunol Med Microbiol 26: 299–307, 1999
11）Maródi L, Korchak HM, Johnston RB: Mechanisms of host defense against Candida species. 1. Phagocytosis by monocytes and monocyte-derived macrophages. J Immunol 146: 2783–2789, 1991
Dectin-1 Mediates the Biological Effects of β-Glucans
Gordon D. Brown, Jurgen Herre, David L. Williams, Janet A. Willment, Andrew S. J. Marshall, and Siamon Gordon
Abstract
The ability of fungal-derived-glucan particles to induce leukocyte activation and the production of inflammatory mediators, such as tumor necrosis factor α, is a well characterized
phenomenon. Although efforts have been made to understand how these carbohydrate polymers
exert their immunomodulatory effects, the receptors involved in generating these responses are unknown. Here we show that Dectin-1 mediates the production of TNF-α in response to zymosan and live fungal pathogens, an activity that occurs at the cell surface andrequires the cytoplasmic tail and immunoreceptor tyrosine activation motif of Dectin-1 as well as Toll-like receptor (TLR)-2 and Myd88. This is the first demonstration that the inflammatory response to pathogens requires recognition by a specific receptor in addition to the TLRs. Furthermore, these studies implicate Dectin-1 in the production of TNF-α in response to fungi, a critical step required for the successful control of these pathogens.
Gordon D. Brown, Jurgen Herre, David L. Williams, Janet A. Willment, Andrew S. J. Marshall, and Siamon Gordon
Abstract
The ability of fungal-derived-glucan particles to induce leukocyte activation and the production of inflammatory mediators, such as tumor necrosis factor α, is a well characterized
phenomenon. Although efforts have been made to understand how these carbohydrate polymers
exert their immunomodulatory effects, the receptors involved in generating these responses are unknown. Here we show that Dectin-1 mediates the production of TNF-α in response to zymosan and live fungal pathogens, an activity that occurs at the cell surface andrequires the cytoplasmic tail and immunoreceptor tyrosine activation motif of Dectin-1 as well as Toll-like receptor (TLR)-2 and Myd88. This is the first demonstration that the inflammatory response to pathogens requires recognition by a specific receptor in addition to the TLRs. Furthermore, these studies implicate Dectin-1 in the production of TNF-α in response to fungi, a critical step required for the successful control of these pathogens.
Hyperglycemia alters PI3k and Akt signaling and leads to endothelial cell proliferative dysfunction
Shubha Varma,2,* Brajesh K. Lal,1,2,* Ruifang Zheng,2 Jerome W. Breslin,1 Satoshi Saito,1,2 Peter J. Pappas,1,2 Robert W. Hobson, II,1,2 and Walter N. Durán1,2
1Program in Vascular Biology, Department of Pharmacology and Physiology, and 2Division of Vascular Surgery, Department of Surgery, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, New Jersey
Submitted 25 October 2004 ; accepted in final form 1 June 2005
Diabetes mellitus is a major risk factor for the development of vascular complications. We hypothesized that hyperglycemia decreases endothelial cell (EC) proliferation and survival via phosphatidylinositol 3-kinase (PI3k) and Akt signaling pathways. We cultured human umbilical vein ECs (HUVEC) in 5, 20, or 40 mM D-glucose. Cells grown in 5, 20, and 40 mM mannitol served as a control for osmotic effects. We measured EC proliferation for up to 15 days. We assessed apoptosis by annexin V and propidium iodide staining and flow cytometry, analyzed cell lysates obtained on culture day 8 for total and phosphorylated PI3k and Akt by Western blot analysis, and measured Akt kinase activity using a GSK fusion protein. HUVEC proliferation was also tested in the presence of pharmacological inhibitors of PI3k-Akt (wortmannin and LY294002) and after transfection with a constitutively active Akt mutant. ECs in media containing 5 mM D-glucose (control) exhibited log-phase growth on days 7–10. D-Glucose at 20 and 40 mM significantly decreased proliferation versus control (P <0.05 for both), whereas mannitol did not impair EC proliferation. Apoptosis increased significantly in HUVEC exposed to 40 mM D-glucose. D-Glucose at 40 mM significantly decreased tyrosine-phosphorylated PI3k, threonine 308-phosphorylated-Akt, and Akt activity relative to control 5 mM D-glucose. Pharmacological inhibition of PI3k-Akt resulted in a dose-dependent decrease in EC proliferation. Transfection with a constitutively active Akt mutant protected ECs by enhancing proliferation when grown in 20 and 40 mM D-glucose. We conclude that D-glucose regulates Akt signaling through threonine phosphorylation of Akt and that hyperglycemia-impaired PI3k-Akt signaling may promote EC proliferative dysfunction in diabetes.
僕も同様のデータを持っています。
Shubha Varma,2,* Brajesh K. Lal,1,2,* Ruifang Zheng,2 Jerome W. Breslin,1 Satoshi Saito,1,2 Peter J. Pappas,1,2 Robert W. Hobson, II,1,2 and Walter N. Durán1,2
1Program in Vascular Biology, Department of Pharmacology and Physiology, and 2Division of Vascular Surgery, Department of Surgery, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, New Jersey
Submitted 25 October 2004 ; accepted in final form 1 June 2005
Diabetes mellitus is a major risk factor for the development of vascular complications. We hypothesized that hyperglycemia decreases endothelial cell (EC) proliferation and survival via phosphatidylinositol 3-kinase (PI3k) and Akt signaling pathways. We cultured human umbilical vein ECs (HUVEC) in 5, 20, or 40 mM D-glucose. Cells grown in 5, 20, and 40 mM mannitol served as a control for osmotic effects. We measured EC proliferation for up to 15 days. We assessed apoptosis by annexin V and propidium iodide staining and flow cytometry, analyzed cell lysates obtained on culture day 8 for total and phosphorylated PI3k and Akt by Western blot analysis, and measured Akt kinase activity using a GSK fusion protein. HUVEC proliferation was also tested in the presence of pharmacological inhibitors of PI3k-Akt (wortmannin and LY294002) and after transfection with a constitutively active Akt mutant. ECs in media containing 5 mM D-glucose (control) exhibited log-phase growth on days 7–10. D-Glucose at 20 and 40 mM significantly decreased proliferation versus control (P <0.05 for both), whereas mannitol did not impair EC proliferation. Apoptosis increased significantly in HUVEC exposed to 40 mM D-glucose. D-Glucose at 40 mM significantly decreased tyrosine-phosphorylated PI3k, threonine 308-phosphorylated-Akt, and Akt activity relative to control 5 mM D-glucose. Pharmacological inhibition of PI3k-Akt resulted in a dose-dependent decrease in EC proliferation. Transfection with a constitutively active Akt mutant protected ECs by enhancing proliferation when grown in 20 and 40 mM D-glucose. We conclude that D-glucose regulates Akt signaling through threonine phosphorylation of Akt and that hyperglycemia-impaired PI3k-Akt signaling may promote EC proliferative dysfunction in diabetes.
Cardioprotective effects of estradiol include the activation of large-conductance Ca2+-activated K+ channels in cardiac mitochondria
Susumu Ohya, Yukiko Kuwata, Kazuho Sakamoto, Katsuhiko Muraki, and Yuji Imaizumi
Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
Submitted 7 January 2005 ; accepted in final form 27 May 2005
The molecular components of the large-conductance Ca2+-activated K+ channels that are functionally expressed in mitochondria (mitoKCa) in cardiac myocytes have not been identified. Our experimental results show that the transcript corresponding to the large-conductance Ca2+-activated K+ channel 1-subunit (BK-1) is substantially expressed in mammalian heart. A yeast two-hybrid assay showed the BK-1 protein can interact with a mitochondrial protein, cytochrome c oxidase subunit I (Cco1). Results from immunocytochemical experiments also demonstrated that BK-1 interacted with Cco1 and colocalized in rat cardiac mitochondria. Furthermore, 17-estradiol, which enhances the activity of the BK channel -subunit only in the presence of the 1-subunit, significantly increased flavoprotein oxidation in rat ventricle myocytes and decreased the rate of cell death under simulated ischemia. Single-channel recordings from mitochondrial inner membrane indicated that the activity of mitoKCa, which had a conductance of 270 pS, was enhanced by 17-estradiol and blocked by paxilline. In combination, the present study revealed a new mechanism for the cardioprotective effects of 17-estradiol, which include the activation of mitoKCa via the interaction with BK-1. BK-1 may be an important molecular component that functionally couples with both Cco1 and mitoKCa pore-forming -subunit.
これは虚血再灌流障害を考えるに当たって，非常に重要な論文です。
ミトコンドリアのBKcaはPKA dependentにミトコンドリア内膜を過分極させ，ミトコンドリアへのCalcium流入を抑制することが，千葉大の佐藤先生たちにより，Circulationに報告されています。
Susumu Ohya, Yukiko Kuwata, Kazuho Sakamoto, Katsuhiko Muraki, and Yuji Imaizumi
Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
Submitted 7 January 2005 ; accepted in final form 27 May 2005
The molecular components of the large-conductance Ca2+-activated K+ channels that are functionally expressed in mitochondria (mitoKCa) in cardiac myocytes have not been identified. Our experimental results show that the transcript corresponding to the large-conductance Ca2+-activated K+ channel 1-subunit (BK-1) is substantially expressed in mammalian heart. A yeast two-hybrid assay showed the BK-1 protein can interact with a mitochondrial protein, cytochrome c oxidase subunit I (Cco1). Results from immunocytochemical experiments also demonstrated that BK-1 interacted with Cco1 and colocalized in rat cardiac mitochondria. Furthermore, 17-estradiol, which enhances the activity of the BK channel -subunit only in the presence of the 1-subunit, significantly increased flavoprotein oxidation in rat ventricle myocytes and decreased the rate of cell death under simulated ischemia. Single-channel recordings from mitochondrial inner membrane indicated that the activity of mitoKCa, which had a conductance of 270 pS, was enhanced by 17-estradiol and blocked by paxilline. In combination, the present study revealed a new mechanism for the cardioprotective effects of 17-estradiol, which include the activation of mitoKCa via the interaction with BK-1. BK-1 may be an important molecular component that functionally couples with both Cco1 and mitoKCa pore-forming -subunit.
これは虚血再灌流障害を考えるに当たって，非常に重要な論文です。
ミトコンドリアのBKcaはPKA dependentにミトコンドリア内膜を過分極させ，ミトコンドリアへのCalcium流入を抑制することが，千葉大の佐藤先生たちにより，Circulationに報告されています。
Frequency-dependent regulation of cardiac Na+/Ca2+ exchanger
Alexander Omelchenko, Ron Bouchard, Sabin Shurraw, Michael Trac, Mark Hnatowich, and Larry V. Hryshko
Institute of Cardiovascular Sciences, University of Manitoba, Faculty of Medicine, St. Boniface Research Centre, Winnipeg, Manitoba, Canada
Submitted 26 October 2004 ; accepted in final form 3 June 2005
The activity of the cardiac Na+/Ca2+ exchanger (NCX1.1) undergoes continuous modulation during the contraction-relaxation cycle because of the accompanying changes in the electrochemical gradients for Na+ and Ca2+. In addition, NCX1.1 activity is also modulated via secondary, ionic regulatory mechanisms mediated by Na+ and Ca2+. In an effort to evaluate how ionic regulation influences exchange activity under pulsatile conditions, we studied the behavior of the cloned NCX1.1 during frequency-controlled changes in intracellular Na+ and Ca+ (Na and Ca). Na+/Ca2+ exchange activity was measured by the giant excised patch-clamp technique with conditions chosen to maximize the extent of Na+- and Ca2+-dependent ionic regulation so that the effects of variables such as pulse frequency and duration could be optimally discerned. We demonstrate that increasing the frequency or duration of solution pulses leads to a progressive decline in pure outward, but not pure inward, Na+/Ca2+ exchange current. However, when the exchanger is permitted to alternate between inward and outward transport modes, both current modes exhibit substantial levels of inactivation. Changes in regulatory Ca2+, or exposure of patches to limited proteolysis by -chymotrypsin, reveal that this "coupling" is due to Na+-dependent inactivation originating from the outward current mode. Under physiological ionic conditions, however, evidence for modulation of exchange currents by Na-dependent inactivation was not apparent. The current approach provides a novel means for assessment of Na+/Ca2+ exchange ionic regulation that may ultimately prove useful in understanding its role under physiological and pathophysiological conditions.
おめるちぇんこは，ラリーの弟子か
Alexander Omelchenko, Ron Bouchard, Sabin Shurraw, Michael Trac, Mark Hnatowich, and Larry V. Hryshko
Institute of Cardiovascular Sciences, University of Manitoba, Faculty of Medicine, St. Boniface Research Centre, Winnipeg, Manitoba, Canada
Submitted 26 October 2004 ; accepted in final form 3 June 2005
The activity of the cardiac Na+/Ca2+ exchanger (NCX1.1) undergoes continuous modulation during the contraction-relaxation cycle because of the accompanying changes in the electrochemical gradients for Na+ and Ca2+. In addition, NCX1.1 activity is also modulated via secondary, ionic regulatory mechanisms mediated by Na+ and Ca2+. In an effort to evaluate how ionic regulation influences exchange activity under pulsatile conditions, we studied the behavior of the cloned NCX1.1 during frequency-controlled changes in intracellular Na+ and Ca+ (Na and Ca). Na+/Ca2+ exchange activity was measured by the giant excised patch-clamp technique with conditions chosen to maximize the extent of Na+- and Ca2+-dependent ionic regulation so that the effects of variables such as pulse frequency and duration could be optimally discerned. We demonstrate that increasing the frequency or duration of solution pulses leads to a progressive decline in pure outward, but not pure inward, Na+/Ca2+ exchange current. However, when the exchanger is permitted to alternate between inward and outward transport modes, both current modes exhibit substantial levels of inactivation. Changes in regulatory Ca2+, or exposure of patches to limited proteolysis by -chymotrypsin, reveal that this "coupling" is due to Na+-dependent inactivation originating from the outward current mode. Under physiological ionic conditions, however, evidence for modulation of exchange currents by Na-dependent inactivation was not apparent. The current approach provides a novel means for assessment of Na+/Ca2+ exchange ionic regulation that may ultimately prove useful in understanding its role under physiological and pathophysiological conditions.
おめるちぇんこは，ラリーの弟子か
RhoA/ROCK signaling is critical to FAK activation by cyclic stretch in cardiac myocytes
Adriana S. Torsoni, Talita M. Marin, Licio A. Velloso, and Kleber G. Franchini
Department of Internal Medicine, School of Medicine, State University of Campinas, Campinas, SP, Brazil
Submitted 13 July 2004 ; accepted in final form 9 May 2005
Focal adhesion kinase (FAK) has been shown to be activated in cardiac myocytes exposed to mechanical stress. However, details of how mechanical stimuli induce FAK activation are unknown. We investigated whether signaling events mediated by the RhoA/Rho-associated coiled coil-containing kinase (ROCK) pathway are involved in regulation of stretch-induced FAK phosphorylation at Tyr397 in neonatal rat ventricular myocytes (NRVMs). Immunostaining showed that RhoA localized to regions of myofilaments alternated with phalloidin (actin) staining. The results of coimmunoprecipitation assays indicated that FAK and RhoA are associated in nonstretched NRVMs, but cyclic stretch significantly reduced the amount of RhoA recovered from anti-FAK immunoprecipitates. Cyclic stretch induced rapid and sustained (up to 2 h) increases in phosphorylation of FAK at Tyr397 and ERK1/2 at Thr202/Tyr204. Blockade of RhoA/ROCK signaling by pharmacological inhibitors of RhoA (Clostridium botulinum C3 exoenzyme) or ROCK (Y-27632, 10 µmol/l, 1 h) markedly attenuated stretch-induced FAK and ERK1/2 phosphorylation. Similar effects were observed in cells treated with the inhibitor of actin polymerization cytochalasin D. Transfection of NRVMs with RhoA antisense oligonucleotide attenuated stretch-induced FAK and ERK1/2 phosphorylation and expression of -myosin heavy chain mRNA. Similar results were seen in cells transfected with FAK antisense oligonucleotide. These findings demonstrate that RhoA/ROCK signaling plays a crucial role in stretch-induced FAK phosphorylation, presumably by coordinating upstream events operationally linked to the actin cytoskeleton.
ろうしたのだ？Baby
Adriana S. Torsoni, Talita M. Marin, Licio A. Velloso, and Kleber G. Franchini
Department of Internal Medicine, School of Medicine, State University of Campinas, Campinas, SP, Brazil
Submitted 13 July 2004 ; accepted in final form 9 May 2005
Focal adhesion kinase (FAK) has been shown to be activated in cardiac myocytes exposed to mechanical stress. However, details of how mechanical stimuli induce FAK activation are unknown. We investigated whether signaling events mediated by the RhoA/Rho-associated coiled coil-containing kinase (ROCK) pathway are involved in regulation of stretch-induced FAK phosphorylation at Tyr397 in neonatal rat ventricular myocytes (NRVMs). Immunostaining showed that RhoA localized to regions of myofilaments alternated with phalloidin (actin) staining. The results of coimmunoprecipitation assays indicated that FAK and RhoA are associated in nonstretched NRVMs, but cyclic stretch significantly reduced the amount of RhoA recovered from anti-FAK immunoprecipitates. Cyclic stretch induced rapid and sustained (up to 2 h) increases in phosphorylation of FAK at Tyr397 and ERK1/2 at Thr202/Tyr204. Blockade of RhoA/ROCK signaling by pharmacological inhibitors of RhoA (Clostridium botulinum C3 exoenzyme) or ROCK (Y-27632, 10 µmol/l, 1 h) markedly attenuated stretch-induced FAK and ERK1/2 phosphorylation. Similar effects were observed in cells treated with the inhibitor of actin polymerization cytochalasin D. Transfection of NRVMs with RhoA antisense oligonucleotide attenuated stretch-induced FAK and ERK1/2 phosphorylation and expression of -myosin heavy chain mRNA. Similar results were seen in cells transfected with FAK antisense oligonucleotide. These findings demonstrate that RhoA/ROCK signaling plays a crucial role in stretch-induced FAK phosphorylation, presumably by coordinating upstream events operationally linked to the actin cytoskeleton.
ろうしたのだ？Baby
PKC--dependent survival signals in diabetic hearts
Ashwani Malhotra,1 Rebecca Begley,3 Barinder P. S. Kang,1 Irmindra Rana,1 Jing Liu,2 Guiping Yang,2 Daria Mochly-Rosen,3 and Leonard G. Meggs1
1Division of Nephrology, Department of Medicine, and 2Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, New Jersey; and 3Department of Molecular Pharmacology, Stanford University, Stanford, California
Diabetes mellitus is complicated by the development of a primary cardiomyopathy, which contributes to the excess morbidity and mortality of this disorder. The protein kinase C (PKC) family of isozymes plays a key role in the cardiac phenotype expressed during postnatal development and in response to pathological stimuli. Hyperglycemia is an activating signal for cardiac PKC isozymes that modulate a myriad of cell events including cell death and survival. The -isozyme of the PKC family transmits a powerful survival signal in cardiac muscle cells. Accordingly, to test the hypothesis that endogenous activation of cardiac PKC- will protect against hyperglycemic cell injury and left ventricular dysfunction, diabetes mellitus was induced using streptozotocin in genetically engineered mice with cardiac-specific expression of the PKC- translocation activator [-receptors for activated C kinase (-RACK)]. The results demonstrate a striking PKC- cardioprotective phenotype in diabetic -RACK (-agonist) mice that is characterized by inhibition of the hyperglycemia apoptosis signal, attenuation of hyperglycemia-mediated oxidative stress, and preservation of parameters of left ventricular pump function. Hearts of diabetic -agonist mice exhibited selective trafficking of PKC- to membrane and mitochondrial compartments, phosphorylation/inactivation of the mitochondrial Bad protein, and inhibition of cytochrome c release. We conclude that activation of endogenous PKC- in hearts of diabetic -agonist mice promotes the survival phenotype, attenuates markers of oxidative stress, and inhibits the negative inotropic properties of chronic hyperglycemia.
バカボンのパパが喜ぶ研究をする人材を育てねばならない。
Ashwani Malhotra,1 Rebecca Begley,3 Barinder P. S. Kang,1 Irmindra Rana,1 Jing Liu,2 Guiping Yang,2 Daria Mochly-Rosen,3 and Leonard G. Meggs1
1Division of Nephrology, Department of Medicine, and 2Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, New Jersey; and 3Department of Molecular Pharmacology, Stanford University, Stanford, California
Diabetes mellitus is complicated by the development of a primary cardiomyopathy, which contributes to the excess morbidity and mortality of this disorder. The protein kinase C (PKC) family of isozymes plays a key role in the cardiac phenotype expressed during postnatal development and in response to pathological stimuli. Hyperglycemia is an activating signal for cardiac PKC isozymes that modulate a myriad of cell events including cell death and survival. The -isozyme of the PKC family transmits a powerful survival signal in cardiac muscle cells. Accordingly, to test the hypothesis that endogenous activation of cardiac PKC- will protect against hyperglycemic cell injury and left ventricular dysfunction, diabetes mellitus was induced using streptozotocin in genetically engineered mice with cardiac-specific expression of the PKC- translocation activator [-receptors for activated C kinase (-RACK)]. The results demonstrate a striking PKC- cardioprotective phenotype in diabetic -RACK (-agonist) mice that is characterized by inhibition of the hyperglycemia apoptosis signal, attenuation of hyperglycemia-mediated oxidative stress, and preservation of parameters of left ventricular pump function. Hearts of diabetic -agonist mice exhibited selective trafficking of PKC- to membrane and mitochondrial compartments, phosphorylation/inactivation of the mitochondrial Bad protein, and inhibition of cytochrome c release. We conclude that activation of endogenous PKC- in hearts of diabetic -agonist mice promotes the survival phenotype, attenuates markers of oxidative stress, and inhibits the negative inotropic properties of chronic hyperglycemia.
バカボンのパパが喜ぶ研究をする人材を育てねばならない。
Review series
IKK/NF-B signaling: balancing life and death – a new approach to cancer therapy
Jun-Li Luo, Hideaki Kamata and Michael Karin
Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology and Cancer Center, School of Medicine, UCSD, La Jolla, California, USA.
Address correspondence to: Michael Karin, Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology and Cancer Center, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA. Phone: (858) 534-1361; Fax: (858) 534-8158; E-mail: karinoffice@ucsd.edu.
IB kinase/NF-B (IKK/NF-B) signaling pathways play critical roles in a variety of physiological and pathological processes. One function of NF-B is promotion of cell survival through induction of target genes, whose products inhibit components of the apoptotic machinery in normal and cancerous cells. NF-B can also prevent programmed necrosis by inducing genes encoding antioxidant proteins. Regardless of mechanism, many cancer cells, of either epithelial or hematopoietic origin, use NF-B to achieve resistance to anticancer drugs, radiation, and death cytokines. Hence, inhibition of IKK-driven NF-B activation offers a strategy for treatment of different malignancies and can convert inflammation-induced tumor growth to inflammation-induced tumor regression.
IKK/NF-B signaling: balancing life and death – a new approach to cancer therapy
Jun-Li Luo, Hideaki Kamata and Michael Karin
Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology and Cancer Center, School of Medicine, UCSD, La Jolla, California, USA.
Address correspondence to: Michael Karin, Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology and Cancer Center, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA. Phone: (858) 534-1361; Fax: (858) 534-8158; E-mail: karinoffice@ucsd.edu.
IB kinase/NF-B (IKK/NF-B) signaling pathways play critical roles in a variety of physiological and pathological processes. One function of NF-B is promotion of cell survival through induction of target genes, whose products inhibit components of the apoptotic machinery in normal and cancerous cells. NF-B can also prevent programmed necrosis by inducing genes encoding antioxidant proteins. Regardless of mechanism, many cancer cells, of either epithelial or hematopoietic origin, use NF-B to achieve resistance to anticancer drugs, radiation, and death cytokines. Hence, inhibition of IKK-driven NF-B activation offers a strategy for treatment of different malignancies and can convert inflammation-induced tumor growth to inflammation-induced tumor regression.
Review
Mitochondria: pharmacological manipulation of cell death
Lisa Bouchier-Hayes, Lydia Lartigue and Donald D. Newmeyer
La Jolla Institute for Allergy and Immunology, Department of Cellular Immunology, San Diego, California, USA.
Address correspondence to: Donald D. Newmeyer, La Jolla Institute for Allergy and Immunology, Department of Cellular Immunology, 10355 Science Center Drive, San Diego, California 92121, USA. Phone: (858) 558-3539; Fax: (858) 558-3526; E-mail: don@liai.org.
Cell death by apoptosis or necrosis is often important in the etiology and treatment of disease. Since mitochondria play important roles in cell death pathways, these organelles are potentially prime targets for therapeutic intervention. Here we discuss the mechanisms through which mitochondria participate in the cell death process and also survey some of the pharmacological approaches that target mitochondria in various ways.
Mitochondria: pharmacological manipulation of cell death
Lisa Bouchier-Hayes, Lydia Lartigue and Donald D. Newmeyer
La Jolla Institute for Allergy and Immunology, Department of Cellular Immunology, San Diego, California, USA.
Address correspondence to: Donald D. Newmeyer, La Jolla Institute for Allergy and Immunology, Department of Cellular Immunology, 10355 Science Center Drive, San Diego, California 92121, USA. Phone: (858) 558-3539; Fax: (858) 558-3526; E-mail: don@liai.org.
Cell death by apoptosis or necrosis is often important in the etiology and treatment of disease. Since mitochondria play important roles in cell death pathways, these organelles are potentially prime targets for therapeutic intervention. Here we discuss the mechanisms through which mitochondria participate in the cell death process and also survey some of the pharmacological approaches that target mitochondria in various ways.
こういう僕にとって自明のことが論文になると複雑な気持ちです。
Research Article
Intensive insulin therapy protects the endothelium of critically ill patients
Lies Langouche1, Ilse Vanhorebeek1, Dirk Vlasselaers1, Sarah Vander Perre1, Pieter J. Wouters1, Kristin Skogstrand2, Troels K. Hansen3 and Greet Van den Berghe1
1Department of Intensive Care Medicine, Katholieke Universiteit Leuven, Leuven, Belgium.
2Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark.
3Immunoendocrine Research Unit, Medical Department M, Aarhus University Hospital, Aarhus, Denmark.
Address correspondence to: Greet Van den Berghe, Department of Intensive Care Medicine, Katholieke Universiteit Leuven, Herestraat 49, B-3000 Leuven, Belgium. Phone: 32-16-34-40-21; Fax: 32-16-34-40-15; E-mail: greta.vandenberghe@med.kuleuven.be.
Received for publication April 18, 2005, and accepted in revised form June 7, 2005.
The vascular endothelium controls vasomotor tone and microvascular flow and regulates trafficking of nutrients and biologically active molecules. When endothelial activation is excessive, compromised microcirculation and subsequent cellular hypoxia contribute to the risk of organ failure. We hypothesized that strict blood glucose control with insulin during critical illness protects the endothelium, mediating prevention of organ failure and death. In this preplanned subanalysis of a large, randomized controlled study, intensive insulin therapy lowered circulating levels of ICAM-1 and tended to reduce E-selectin levels in patients with prolonged critical illness, which reflects reduced endothelial activation. This effect was not brought about by altered levels of endothelial stimuli, such as cytokines or VEGF, or by upregulation of eNOS. In contrast, prevention of hyperglycemia by intensive insulin therapy suppressed iNOS gene expression in postmortem liver and skeletal muscle, possibly in part via reduced NF-B activation, and lowered the elevated circulating NO levels in both survivors and nonsurvivors. These effects on the endothelium statistically explained a significant part of the improved patient outcome with intensive insulin therapy. In conclusion, maintaining normoglycemia with intensive insulin therapy during critical illness protects the endothelium, likely in part via inhibition of excessive iNOS-induced NO release, and thereby contributes to prevention of organ failure and death.
僕が5年前に考えていて，いくつかデータを持っているものがこうやってきちんと論文になって発表されると，すごいなあと思うとともに，どことなく悔しいです。しかし研究をするひとだけが知っている大変な苦労があるのだと思います。1日は24時間しかないので，やはり，共同研究者を増やしていくしかないように思っています。
Research Article
Intensive insulin therapy protects the endothelium of critically ill patients
Lies Langouche1, Ilse Vanhorebeek1, Dirk Vlasselaers1, Sarah Vander Perre1, Pieter J. Wouters1, Kristin Skogstrand2, Troels K. Hansen3 and Greet Van den Berghe1
1Department of Intensive Care Medicine, Katholieke Universiteit Leuven, Leuven, Belgium.
2Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark.
3Immunoendocrine Research Unit, Medical Department M, Aarhus University Hospital, Aarhus, Denmark.
Address correspondence to: Greet Van den Berghe, Department of Intensive Care Medicine, Katholieke Universiteit Leuven, Herestraat 49, B-3000 Leuven, Belgium. Phone: 32-16-34-40-21; Fax: 32-16-34-40-15; E-mail: greta.vandenberghe@med.kuleuven.be.
Received for publication April 18, 2005, and accepted in revised form June 7, 2005.
The vascular endothelium controls vasomotor tone and microvascular flow and regulates trafficking of nutrients and biologically active molecules. When endothelial activation is excessive, compromised microcirculation and subsequent cellular hypoxia contribute to the risk of organ failure. We hypothesized that strict blood glucose control with insulin during critical illness protects the endothelium, mediating prevention of organ failure and death. In this preplanned subanalysis of a large, randomized controlled study, intensive insulin therapy lowered circulating levels of ICAM-1 and tended to reduce E-selectin levels in patients with prolonged critical illness, which reflects reduced endothelial activation. This effect was not brought about by altered levels of endothelial stimuli, such as cytokines or VEGF, or by upregulation of eNOS. In contrast, prevention of hyperglycemia by intensive insulin therapy suppressed iNOS gene expression in postmortem liver and skeletal muscle, possibly in part via reduced NF-B activation, and lowered the elevated circulating NO levels in both survivors and nonsurvivors. These effects on the endothelium statistically explained a significant part of the improved patient outcome with intensive insulin therapy. In conclusion, maintaining normoglycemia with intensive insulin therapy during critical illness protects the endothelium, likely in part via inhibition of excessive iNOS-induced NO release, and thereby contributes to prevention of organ failure and death.
僕が5年前に考えていて，いくつかデータを持っているものがこうやってきちんと論文になって発表されると，すごいなあと思うとともに，どことなく悔しいです。しかし研究をするひとだけが知っている大変な苦労があるのだと思います。1日は24時間しかないので，やはり，共同研究者を増やしていくしかないように思っています。
Research Article
PI3K rescues the detrimental effects of chronic Akt activation in the heart during ischemia/reperfusion injury
Tomohisa Nagoshi1, Takashi Matsui1, Takuma Aoyama1, Annarosa Leri2, Piero Anversa2, Ling Li1, Wataru Ogawa3, Federica del Monte1, Judith K. Gwathmey4,5, Luanda Grazette1, Brian Hemmings6, David A. Kass7, Hunter C. Champion7 and Anthony Rosenzweig1
1Program in Cardiovascular Gene Therapy, Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
2Department of Medicine, New York Medical College, Valhalla, New York, USA.
3Department of Clinical Molecular Medicine, Division of Diabetes, Digestive, and Kidney Diseases, Kobe University Graduate School of Medicine, Kobe, Japan.
4Gwathmey Inc., Cambridge, Massachusetts, USA.
5Harvard Medical School, Boston, Massachusetts, USA.
6Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.
7Division of Cardiology, The Johns Hopkins Hospital, Baltimore, Maryland, USA.
Address correspondence to: Anthony Rosenzweig, Program in Cardiovascular Gene Therapy, Massachusetts General Hospital, 114 16th Street, Room 2600, Charlestown, Massachusetts 02129, USA. Phone: (617) 726-8286; Fax: (617) 724-7387; E-mail: arosenzweig@partners.org.
Received for publication August 18, 2004, and accepted in revised form March 29, 2005.
Acute activation of the serine-threonine kinase Akt is cardioprotective and reduces both infarction and dysfunction after ischemia/reperfusion injury (IRI). However, less is known about the chronic effects of Akt activation in the heart, and, paradoxically, Akt is activated in samples from patients with chronic heart failure. We generated Tg mice with cardiac-specific expression of either activated (myristoylated [myr]) or dominant-negative (dn) Akt and assessed their response to IRI in an ex vivo model. While dn-Akt hearts demonstrated a moderate reduction in functional recovery after IRI, no function was restored in any of the myr-Akt–Tg hearts. Moreover, infarcts were dramatically larger in myr-Akt–Tg hearts. Biochemical analyses demonstrated that chronic Akt activation induces feedback inhibition of PI3K activity through both proteasome-dependent degradation of insulin receptor substrate–1 (IRS-1) and inhibition of transcription of IRS-1 as well as that of IRS-2. To test the functional significance of these signaling changes, we performed in vivo cardiac gene transfer with constitutively active PI3K in myr-Akt–Tg mice. Restoration of PI3K rescued function and reduced injury after IRI. These data demonstrate that PI3K-dependent but Akt-independent effectors are required for full cardioprotection and suggest a mechanism by which chronic Akt activation can become maladaptive.
さすがにすばらしい研究です。
PI3K rescues the detrimental effects of chronic Akt activation in the heart during ischemia/reperfusion injury
Tomohisa Nagoshi1, Takashi Matsui1, Takuma Aoyama1, Annarosa Leri2, Piero Anversa2, Ling Li1, Wataru Ogawa3, Federica del Monte1, Judith K. Gwathmey4,5, Luanda Grazette1, Brian Hemmings6, David A. Kass7, Hunter C. Champion7 and Anthony Rosenzweig1
1Program in Cardiovascular Gene Therapy, Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
2Department of Medicine, New York Medical College, Valhalla, New York, USA.
3Department of Clinical Molecular Medicine, Division of Diabetes, Digestive, and Kidney Diseases, Kobe University Graduate School of Medicine, Kobe, Japan.
4Gwathmey Inc., Cambridge, Massachusetts, USA.
5Harvard Medical School, Boston, Massachusetts, USA.
6Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.
7Division of Cardiology, The Johns Hopkins Hospital, Baltimore, Maryland, USA.
Address correspondence to: Anthony Rosenzweig, Program in Cardiovascular Gene Therapy, Massachusetts General Hospital, 114 16th Street, Room 2600, Charlestown, Massachusetts 02129, USA. Phone: (617) 726-8286; Fax: (617) 724-7387; E-mail: arosenzweig@partners.org.
Received for publication August 18, 2004, and accepted in revised form March 29, 2005.
Acute activation of the serine-threonine kinase Akt is cardioprotective and reduces both infarction and dysfunction after ischemia/reperfusion injury (IRI). However, less is known about the chronic effects of Akt activation in the heart, and, paradoxically, Akt is activated in samples from patients with chronic heart failure. We generated Tg mice with cardiac-specific expression of either activated (myristoylated [myr]) or dominant-negative (dn) Akt and assessed their response to IRI in an ex vivo model. While dn-Akt hearts demonstrated a moderate reduction in functional recovery after IRI, no function was restored in any of the myr-Akt–Tg hearts. Moreover, infarcts were dramatically larger in myr-Akt–Tg hearts. Biochemical analyses demonstrated that chronic Akt activation induces feedback inhibition of PI3K activity through both proteasome-dependent degradation of insulin receptor substrate–1 (IRS-1) and inhibition of transcription of IRS-1 as well as that of IRS-2. To test the functional significance of these signaling changes, we performed in vivo cardiac gene transfer with constitutively active PI3K in myr-Akt–Tg mice. Restoration of PI3K rescued function and reduced injury after IRI. These data demonstrate that PI3K-dependent but Akt-independent effectors are required for full cardioprotection and suggest a mechanism by which chronic Akt activation can become maladaptive.
さすがにすばらしい研究です。
宿敵オニール
Akt1 in the cardiovascular system: friend or foe?
Brian T. O’Neill and E. Dale Abel
Division of Endocrinology, Metabolism and Diabetes and Program in Human Molecular Biology and Genetics, University of Utah School of Medicine, Salt Lake City, Utah, USA.
Address correspondence to: E. Dale Abel, Division of Endocrinology, Metabolism and Diabetes, Program in Human Molecular Biology and Genetics, 15 North 2030 East, Building 533 Room 3410B, Salt Lake City, Utah 84112, USA. Phone: (801) 585-0727; Fax: (801) 585-0701; E-mail: dale.abel@hmbg.utah.edu.
Akt is an important signaling molecule that modulates many cellular processes such as cell growth, survival, and metabolism. Akt activation has been proposed as a potential strategy for increasing cardiomyocyte survival following ischemia. In mammalian cells, 3 distinct isoforms of Akt exist, but their precise roles in cardiovascular biology were previously unknown. Three separate studies published in this issue of the JCI now provide important new insight into the central role of Akt1 in the regulation of angiogenesis and the maladaptive or deleterious consequences of chronic unregulated Akt activation in the heart (see the related articles beginning on pages 2108, 2119, and 2128). Here we discuss the implications of these exciting new studies.
Aktを見えるようにしてみせよう，ホトトギス。
Akt1 in the cardiovascular system: friend or foe?
Brian T. O’Neill and E. Dale Abel
Division of Endocrinology, Metabolism and Diabetes and Program in Human Molecular Biology and Genetics, University of Utah School of Medicine, Salt Lake City, Utah, USA.
Address correspondence to: E. Dale Abel, Division of Endocrinology, Metabolism and Diabetes, Program in Human Molecular Biology and Genetics, 15 North 2030 East, Building 533 Room 3410B, Salt Lake City, Utah 84112, USA. Phone: (801) 585-0727; Fax: (801) 585-0701; E-mail: dale.abel@hmbg.utah.edu.
Akt is an important signaling molecule that modulates many cellular processes such as cell growth, survival, and metabolism. Akt activation has been proposed as a potential strategy for increasing cardiomyocyte survival following ischemia. In mammalian cells, 3 distinct isoforms of Akt exist, but their precise roles in cardiovascular biology were previously unknown. Three separate studies published in this issue of the JCI now provide important new insight into the central role of Akt1 in the regulation of angiogenesis and the maladaptive or deleterious consequences of chronic unregulated Akt activation in the heart (see the related articles beginning on pages 2108, 2119, and 2128). Here we discuss the implications of these exciting new studies.
Aktを見えるようにしてみせよう，ホトトギス。
Review Series
Inherited disorders of voltage-gated sodium channels
Alfred L. George, Jr.
Division of Genetic Medicine, Departments of Medicine and Pharmacology, Vanderbilt University, Nashville, Tennessee, USA.
Address correspondence to: Alfred L. George Jr., Division of Genetic Medicine, 529 Light Hall, Vanderbilt University, Nashville, Tennessee 37232-0275, USA. Phone: (615) 936-2660; Fax: (615) 936-2661; E-mail: al.george@vanderbilt.edu.
A variety of inherited human disorders affecting skeletal muscle contraction, heart rhythm, and nervous system function have been traced to mutations in genes encoding voltage-gated sodium channels. Clinical severity among these conditions ranges from mild or even latent disease to life-threatening or incapacitating conditions. The sodium channelopathies were among the first recognized ion channel diseases and continue to attract widespread clinical and scientific interest. An expanding knowledge base has substantially advanced our understanding of structure-function and genotype-phenotype relationships for voltage-gated sodium channels and provided new insights into the pathophysiological basis for common diseases such as cardiac arrhythmias and epilepsy.
Inherited disorders of voltage-gated sodium channels
Alfred L. George, Jr.
Division of Genetic Medicine, Departments of Medicine and Pharmacology, Vanderbilt University, Nashville, Tennessee, USA.
Address correspondence to: Alfred L. George Jr., Division of Genetic Medicine, 529 Light Hall, Vanderbilt University, Nashville, Tennessee 37232-0275, USA. Phone: (615) 936-2660; Fax: (615) 936-2661; E-mail: al.george@vanderbilt.edu.
A variety of inherited human disorders affecting skeletal muscle contraction, heart rhythm, and nervous system function have been traced to mutations in genes encoding voltage-gated sodium channels. Clinical severity among these conditions ranges from mild or even latent disease to life-threatening or incapacitating conditions. The sodium channelopathies were among the first recognized ion channel diseases and continue to attract widespread clinical and scientific interest. An expanding knowledge base has substantially advanced our understanding of structure-function and genotype-phenotype relationships for voltage-gated sodium channels and provided new insights into the pathophysiological basis for common diseases such as cardiac arrhythmias and epilepsy.
Research Article
Ets-1 is a critical regulator of Ang II-mediated vascular inflammation and remodeling
Yumei Zhan1,2, Courtney Brown1,2, Elizabeth Maynard1,2, Aleksandra Anshelevich1,2, Weihua Ni1,2, I-Cheng Ho3 and Peter Oettgen1,2
1Division of Cardiology, Beth Israel Deaconess Medical Center, and
2Department of Medicine and New England Baptist Bone and Joint Institute, Harvard Institutes of Medicine, Boston, Massachusetts, USA.
3Division of Rheumatology, Allergy, and Immunology, Brigham and Women’s Hospital, Boston, Massachusetts, USA.
Address correspondence to: Peter Oettgen, Harvard Institutes of Medicine, 4 Blackfan Circle, Boston, Massachusetts 02115, USA. Phone: (617) 667-3390; Fax: (617) 975-5299; E-mail: joettgen@caregroup.harvard.edu.
Ang II is a central mediator of vascular inflammation and remodeling. The transcription factor Ets-1 is rapidly induced in vascular smooth muscle and endothelial cells of the mouse thoracic aorta in response to systemic Ang II infusion. Arterial wall thickening, perivascular fibrosis, and cardiac hypertrophy are significantly diminished in Ets1–/– mice compared with control mice in response to Ang II. The induction of 2 known targets of Ets-1, cyclin-dependent kinase inhibitor p21CIP and plasminogen activator inhibitor–1 (PAI-1), by Ang II is markedly blunted in the aorta of Ets1–/– mice compared with wild-type controls. Expression of p21CIP in VSMCs leads to cellular hypertrophy, whereas expression of p21CIP in endothelial cells is associated with cell cycle arrest, apoptosis, and endothelial dysfunction. PAI-1 promotes the development of perivascular fibrosis. We have identified monocyte chemoattractant protein–1 (MCP-1) as a novel target for Ets-1. Expression of MCP-1 is similarly reduced in Ets1–/– mice compared with control mice in response to Ang II, which results in significantly diminished recruitment of T cells and macrophages to the vessel wall. In summary, our results support a critical role for Ets-1 as a transcriptional mediator of vascular inflammation and remodeling in response to Ang II.
Ets-1 is a critical regulator of Ang II-mediated vascular inflammation and remodeling
Yumei Zhan1,2, Courtney Brown1,2, Elizabeth Maynard1,2, Aleksandra Anshelevich1,2, Weihua Ni1,2, I-Cheng Ho3 and Peter Oettgen1,2
1Division of Cardiology, Beth Israel Deaconess Medical Center, and
2Department of Medicine and New England Baptist Bone and Joint Institute, Harvard Institutes of Medicine, Boston, Massachusetts, USA.
3Division of Rheumatology, Allergy, and Immunology, Brigham and Women’s Hospital, Boston, Massachusetts, USA.
Address correspondence to: Peter Oettgen, Harvard Institutes of Medicine, 4 Blackfan Circle, Boston, Massachusetts 02115, USA. Phone: (617) 667-3390; Fax: (617) 975-5299; E-mail: joettgen@caregroup.harvard.edu.
Ang II is a central mediator of vascular inflammation and remodeling. The transcription factor Ets-1 is rapidly induced in vascular smooth muscle and endothelial cells of the mouse thoracic aorta in response to systemic Ang II infusion. Arterial wall thickening, perivascular fibrosis, and cardiac hypertrophy are significantly diminished in Ets1–/– mice compared with control mice in response to Ang II. The induction of 2 known targets of Ets-1, cyclin-dependent kinase inhibitor p21CIP and plasminogen activator inhibitor–1 (PAI-1), by Ang II is markedly blunted in the aorta of Ets1–/– mice compared with wild-type controls. Expression of p21CIP in VSMCs leads to cellular hypertrophy, whereas expression of p21CIP in endothelial cells is associated with cell cycle arrest, apoptosis, and endothelial dysfunction. PAI-1 promotes the development of perivascular fibrosis. We have identified monocyte chemoattractant protein–1 (MCP-1) as a novel target for Ets-1. Expression of MCP-1 is similarly reduced in Ets1–/– mice compared with control mice in response to Ang II, which results in significantly diminished recruitment of T cells and macrophages to the vessel wall. In summary, our results support a critical role for Ets-1 as a transcriptional mediator of vascular inflammation and remodeling in response to Ang II.
アクセス
トータル
ランキング
