Differing roles of mitochondrial nitric oxide synthase in cardiomyocytes and urothelial cells
Differing roles of mitochondrial nitric oxide synthase in cardiomyocytes and urothelial cells
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DOI：
10.1152/ajpheart.00737.2003
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发表时间：
2004-01-01
影响因子：
4.8
通讯作者：
Peterson, J
中科院分区：
文献类型：
--
作者：
Kanai, A;Epperly, M;Peterson, J
线粒体一氧化氮合酶（mtNOS）自1995年被首次报道以来一直存在争议。我们已经解决了这个问题，通过直接微传感器测量从小鼠心脏分离的线粒体中NO的产生。线粒体NO的产生被Ca 2+刺激，并通过阻断生电Ca 2+摄取或使用NOS拮抗剂来抑制。心脏mtNOS被确定为神经元亚型的情况下，NO生产的小鼠线粒体缺乏神经元，但不是内皮或诱导亚型。在肌营养不良蛋白缺陷（mdx）小鼠的心肌细胞中，检测到细胞内Ca 2+升高、线粒体NO产生增加、氧化磷酸化减慢和ATP产生减少。对mtNOS的抑制增加了mdx中的收缩性，但在野生型心肌细胞中没有，表明mtNOS可以保护细胞免于过度收缩。mtNOS也与辐射诱导的细胞损伤有关。在照射的大鼠/小鼠膀胱中，我们有证据表明，尿道产生的NO损害膀胱腔的尿路上皮“伞”细胞。这种损伤破坏了渗透屏障，从而产生了发展放射性膀胱炎的可能性。RT-PCR和Southern印迹分析表明，线粒体NOS仅限于伞细胞，扫描电镜显示伞细胞被辐射选择性损伤。同时微传感器测量表明，辐射增加NO和过氧亚硝酸盐（ONOO（-））在这些细胞中的生产，这可以通过转染锰超氧化物歧化酶（MnSOD）或滴注NOS拮抗剂在照射或照射的膀胱没有mtNOS。这些研究表明，mtNOS是在心肌细胞和尿路上皮细胞，它是来自神经元亚型，它可以是保护性的或有害的。
The existence of mitochondrial nitric oxide ( NO) synthase ( mtNOS) has been controversial since it was first reported in 1995. We have addressed this issue by making direct microsensor measurements of NO production in the mitochondria isolated from mouse hearts. Mitochondrial NO production was stimulated by Ca2+ and inhibited by blocking electrogenic Ca2+ uptake or by using NOS antagonists. Cardiac mtNOS was identified as the neuronal isoform by the absence of NO production in the mitochondria of mice lacking the neuronal but not the endothelial or inducible isoforms. In cardiomyocytes from dystrophin- deficient ( mdx) mice, elevated intracellular Ca2+, increased mitochondrial NO production, slower oxidative phosphorylation, and decreased ATP production were detected. Inhibition of mtNOS increased contractility in mdx but not in wild- type cardiomyocytes, indicating that mtNOS may protect the cells from overcontracting. mtNOS was also implicated in radiation- induced cell damage. In irradiated rat/ mouse urinary bladders, we have evidence that mitochondrially produced NO damages the urothelial " umbrella" cells that line the bladder lumen. This damage disrupts the permeability barrier thereby creating the potential to develop radiation cystitis. RT- PCR and Southern blot analyses indicate that mtNOS is restricted to the umbrella cells, which scanning electron micrographs show are selectively damaged by radiation. Simultaneous microsensor measurements demonstrate that radiation increases NO and peroxynitrite ( ONOO (-)) production in these cells, which can be prevented by transfection with manganese superoxide dismutase ( MnSOD) or instillation of NOS antagonists during irradiation or irradiation of bladders devoid of mtNOS. These studies demonstrate that mtNOS is in the cardiomyocytes and urothelial cells, that it is derived from the neuronal isoform, and that it can be either protective or detrimental.