Department of Medicine, Brown Medical School, Brown University, Providence, Rhode Island, USA.
Am J Physiol Heart Circ Physiol. 2010 Jun;298(6):H2154-63. doi: 10.1152/ajpheart.01015.2009. Epub 2010 Apr 9.
We have recently demonstrated that the inhibition of histone deacetylases (HDAC) protects the heart against ischemia-reperfusion (I/R) injury. The mechanism by which HDAC inhibition confers myocardial protection remains unknown. The purpose of this study is to investigate whether the disruption of NF-kappaB p50 would eliminate the protective effects of HDAC inhibition. Wild-type and NF-kappaB p50-deficient mice were treated with trichostatin A (TSA; 0.1 mg/kg ip), a potent inhibitor of HDACs. Twenty-four hours later, the hearts were perfused in Langendorff model and subjected to 30 min of ischemia and 30 min of reperfusion. Inhibition of HDACs by TSA in wild-type mice produced marked improvements in left ventricular end-diastolic pressure, left ventricular rate pressure product, and the reduction of infarct size compared with non-TSA-treated group. TSA-induced cardioprotection in wild-type animals was absent with genetic deletion of NF-kappaB p50 subunit. Notably, Western blot displayed a significant increase in nuclear NF-kappaB p50 and the immunoprecipitation demonstrated a remarkable acetylation of NF-kappaB p50 at lysine residues following HDAC inhibition. EMSA exhibited a subsequent increase in NF-kappaB DNA binding activity. Luciferase assay demonstrated an activation of NF-kappaB by HDAC inhibition. The pretreatment of H9c2 cardiomyoblasts with TSA (50 nmol/l) decreased cell necrosis and increased in cell viability in simulated ischemia. The resistance of H9c2 cardiomyoblasts to simulated ischemia by HDAC inhibition was eliminated by genetic knockdown of NF-kappaB p50 with transfection of NF-kappaB p50 short interfering RNA but not scrambled short interfering RNA. These results suggest that NF-kappaB p50 acetylation and activation play a pivotal role in HDAC inhibition-induced cardioprotection.
我们最近证明，组蛋白去乙酰化酶（HDAC）的抑制可保护心脏免受缺血再灌注（I/R）损伤。HDAC 抑制赋予心肌保护作用的机制尚不清楚。本研究旨在探讨 NF-κB p50 的破坏是否会消除 HDAC 抑制的保护作用。野生型和 NF-κB p50 缺陷型小鼠用 Trichostatin A（TSA；0.1mg/kg ip）治疗，一种有效的 HDAC 抑制剂。24 小时后，心脏在 Langendorff 模型中灌注，并进行 30min 缺血和 30min 再灌注。与非 TSA 处理组相比，TSA 抑制 HDAC 可使野生型小鼠的左室舒张末期压、左室压心率乘积显著改善，并减少梗死面积。NF-κB p50 亚基基因缺失消除了 TSA 在野生型动物中的心脏保护作用。值得注意的是，Western blot 显示核 NF-κB p50 显著增加，免疫沉淀显示 HDAC 抑制后 NF-κB p50 的赖氨酸残基乙酰化显著增加。EMSA 显示 NF-κB DNA 结合活性随后增加。荧光素酶测定显示 HDAC 抑制激活 NF-κB。TSA（50nmol/L）预处理 H9c2 心肌细胞可减少细胞坏死并增加模拟缺血时的细胞活力。用 NF-κB p50 短发夹 RNA 转染而不是用 scrambled 短发夹 RNA 转染消除了 NF-κB p50 基因敲低对 HDAC 抑制诱导的 H9c2 心肌细胞对模拟缺血的抵抗力。这些结果表明，NF-κB p50 乙酰化和激活在 HDAC 抑制诱导的心脏保护中起关键作用。
