Nicorandil regulates Bcl-2 family proteins and protects cardiac myocytes against hypoxia-induced apoptosis
Nicorandil regulates Bcl-2 family proteins and protects cardiac myocytes against hypoxia-induced apoptosis
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DOI：
10.1016/j.yjmcc.2006.01.020
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发表时间：
2006-04-01
影响因子：
5
通讯作者：
Matsubara, H
中科院分区：
文献类型：
--
作者：
Nishikawa, S;Tatsumi, T;Matsubara, H
尼可地尔已被证明可通过打开线粒体ATP敏感性钾（mitoK（ATP））通道和抗氧化应激的硝酸盐样作用抑制心肌细胞凋亡。然而，缺氧条件下尼可地尔介导的心脏保护作用的详细机制仍不清楚。本研究检测尼可地尔是否可以通过调节缺氧心肌细胞中Bcl-2家族蛋白来抑制凋亡。新生大鼠心肌细胞缺氧7小时。富葡萄糖条件下缺氧诱导的心肌细胞凋亡（13.9 +/- 0.9%）。心肌细胞凋亡伴随着线粒体膜电位（Δ Psi（m））的损失，细胞色素c从线粒体释放到胞质溶胶中，和半胱天冬酶-3的激活。缺氧还显著增加Bax和降低Bcl-2 mRNA和蛋白表达，从而增加Bax/Bcl-2比值。尼可地尔100 μ mol/l通过抑制Delta Psi（m）损失和细胞色素c易位，显著降低了凋亡心肌细胞的百分比（7.2 +/- 0.5%）。500 μ mol/l 5-羟基癸酸酯（一种选择性mitoK（ATP）通道拮抗剂）或10 μ mol/l 1H-[1，2，4]oxidazolo[4，3-a]quinoxalin-1-one（ODQ，一种可溶性鸟苷酸环化酶抑制剂）联合给药可部分但显著抑制尼可地尔的这些作用。尼可地尔可显著抑制缺氧诱导的Bax和Bcl-2表达的变化，并伴随着线粒体Bax和Bcl-2免疫反应性的增加和降低。尼可地尔对Bax和Bcl-2表达的这些作用分别被ODQ和5-HD联合处理显著减弱。共处理KT 5823（一种蛋白激酶G抑制剂）可显著阻断尼可地尔对Bax表达的影响，而8-溴环鸟苷3 '，5'单磷酸（8-溴-cGMP）（一种cGMP类似物）可模拟尼可地尔对Bax表达的影响。目前的研究表明，尼可地尔通过开放线粒体K（ATP）通道和一氧化氮-cGMP信号传导调节Bcl-2家族蛋白，并抑制缺氧诱导的线粒体死亡途径。(c)2006爱思唯尔有限公司保留所有权利。
Nicorandil has been shown to inhibit myocyte apoptosis by opening of mitochondrial ATP-sensitive potassium (mitoK(ATP)) channels and nitrate-like effect against oxidative stress. However, the detailed mechanism of nicorandil-mediated cardioprotection under hypoxic conditions remains to be largely unknown. The present study examined whether nicorandil can inhibit apoptosis via regulation of Bcl-2 family proteins in hypoxic myocytes. Neonatal rat cardiac myocytes were exposed to hypoxia for 7 hours. Hypoxia-induced myocyte apoptosis (13.9 +/- 0.9%) under glucose-rich conditions. Myocyte apoptosis was accompanied by loss of mitochondrial membrane potential (Delta Psi(m)), cytochrome c release from mitochondria into cytosol, and activation of caspase-3. Hypoxia also significantly increased Bax and decreased Bcl-2 mRNA and protein expression, thereby increasing Bax/Bcl-2 ratio. Nicorandil 100 mu mol/l significantly decreased the percentage of apoptotic myocytes (7.2 +/- 0.5%) by inhibiting loss of Delta Psi(m) and translocation of cytochrome c. These effects of nicorandil were partially but significantly inhibited by cotreatment of either 500 mu mol/l 5-hydroxydecanoate, a selective mitoK(ATP) channel antagonist, or 10 mu mol/l 1H-[1,2,4]oxidazolo[4,3-a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylate cyclase. Moreover, nicorandil significantly inhibited the hypoxia-induced changes in Bax and Bcl-2 expression, and concomitant increased Bax and decreased Bcl-2 immunoreactivity in mitochondria. These effects of nicorandil in Bax and Bcl-2 expression were significantly blunted by cotreatment of ODQ and 5-HD, respectively. Cotreatment of KT5823, an inhibitor of protein kinase G, significantly blocked the effect of nicorandil on Bax expression and 8-bromo-cyclic guanosine 3',5' monophosphate (8-bromo-cGMP), a cGMP analog, mimicked the effect of nicorandil on Bax expression. The present study demonstrates that nicorandil regulates Bcl-2 family proteins via opening of mitoK(ATP) channels and nitric oxide-cGMP signaling and inhibits hypoxia-induced mitochondrial death pathway. (c) 2006 Elsevier Ltd. All rights reserved.