Ndufs2, a Core Subunit of Mitochondrial Complex I, Is Essential for Acute Oxygen-Sensing and Hypoxic Pulmonary Vasoconstriction
Ndufs2, a Core Subunit of Mitochondrial Complex I, Is Essential for Acute Oxygen-Sensing and Hypoxic Pulmonary Vasoconstriction
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DOI：
10.1161/circresaha.118.314284
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发表时间：
2019-06-07
影响因子：
20.1
通讯作者：
Archer, Stephen L.
中科院分区：
文献类型：
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作者：
Dunham-Snary, Kimberly J.;Wu, Danchen;Archer, Stephen L.
原理：缺氧性肺血管收缩(HPV)通过匹配通气量和灌注量来优化全身供氧。人乳头瘤病毒(HPV)是肺动脉平滑肌细胞(PASMCs)固有的。缺氧会扩张全身动脉，包括肾动脉。缺氧是通过线粒体衍生的活性氧物种的变化来感受的，特别是过氧化氢(H_2O_2)([H_2O_2](MITO))。[H_2O_2]减少(MITO)通过离子通道的还原-氧化调节增加细胞内钙([Ca~(2+)](I))，从而提高肺血管张力。虽然HPV被复杂的I抑制剂鱼藤酮模仿，但O-2传感器的分子特性尚不清楚。目的：探讨化合物I的鱼藤酮结合部位Ndufs2(NADH[烟酰胺腺嘌呤二核苷酸]脱氢酶[泛醌]铁硫蛋白2)在肺血管氧感受中的作用。方法和结果：将从正常和慢性低氧大鼠肺和肾线粒体分离的线粒体条件培养液输入到离体肺生物测定中。来自常氧肺的线粒体条件培养液比来自慢性低氧肺或肾脏的线粒体条件培养液含有更多的H_2O_2，并通过过氧化氢酶依赖的机制独特地减弱HPV。在PASMC中，急性缺氧在112+/-7秒内降低了H_2O_2，随后在205+/-34秒内升高了细胞内钙离子浓度[Ca~(2+)](I)。低氧对肾动脉SMC[Ca~(2+)](I)无影响。低氧降低PASMC胞浆和线粒体H_2O_2，增加肾动脉SMC胞浆H_2O_2。Ndufs2在PASMC中的表达高于肾动脉SMC。在PASMC中，siNdufs2(经Ndufs2 siRNA处理的细胞/组织)减少了常氧的H_2O_2，阻止了缺氧性[Ca~(2+)](I)的升高，并模拟了慢性缺氧的一些方面，包括降低复合体I的活性，提高烟酰胺腺嘌呤二核苷酸(NADH/NAD(+))的比值和降低氧敏感离子通道Kv1.5的表达。敲除复合体I(Ndufs1，NADH[烟酰胺腺嘌呤二核苷酸]脱氢酶[泛醌]铁硫蛋白1)或其他可能的氧感受器线粒体亚基(复合体III的Rieske Fe-S中心和复合体IV中的COX4I2[细胞色素c氧化酶亚基4异构体2])中的另一个Fe-S中心，对缺氧性[Ca~(2+)](I)的升高没有影响。在体内，siNdufs2显著降低缺氧和鱼藤酮诱导的收缩，而增强苯肾上腺素诱导的收缩。结论：Ndufs2在氧敏和人乳头状瘤病毒中是必需的。
Rationale: Hypoxic pulmonary vasoconstriction (HPV) optimizes systemic oxygen delivery by matching ventilation to perfusion. HPV is intrinsic to pulmonary artery smooth muscle cells (PASMCs). Hypoxia dilates systemic arteries, including renal arteries. Hypoxia is sensed by changes in mitochondrial-derived reactive oxygen species, notably hydrogen peroxide (H2O2) ([H2O2](mito)). Decreases in [H2O2](mito) elevate pulmonary vascular tone by increasing intracellular calcium ([Ca2+](i)) through reduction-oxidation regulation of ion channels. Although HPV is mimicked by the Complex I inhibitor, rotenone, the molecular identity of the O-2 sensor is unknown. Objective: To determine the role of Ndufs2 (NADH [nicotinamide adenine dinucleotide] dehydrogenase [ubiquinone] iron-sulfur protein 2), Complex I's rotenone binding site, in pulmonary vascular oxygen-sensing. Methods and Results: Mitochondria-conditioned media from pulmonary and renal mitochondria isolated from normoxic and chronically hypoxic rats were infused into an isolated lung bioassay. Mitochondria-conditioned media from normoxic lungs contained more H2O2 than mitochondria-conditioned media from chronic hypoxic lungs or kidneys and uniquely attenuated HPV via a catalase-dependent mechanism. In PASMC, acute hypoxia decreased H2O2 within 112 +/- 7 seconds, followed, within 205 +/- 34 seconds, by increased intracellular calcium concentration, [Ca2+](i). Hypoxia had no effects on [Ca2+](i) in renal artery SMC. Hypoxia decreases both cytosolic and mitochondrial H2O2 in PASMC while increasing cytosolic H2O2 in renal artery SMC. Ndufs2 expression was greater in PASMC versus renal artery SMC. Lung Ndufs2 cysteine residues became reduced during acute hypoxia and both hypoxia and reducing agents caused functional inhibition of Complex I. In PASMC, siNdufs2 (cells/tissue treated with Ndufs2 siRNA) decreased normoxic H2O2, prevented hypoxic increases in [Ca2+](i), and mimicked aspects of chronic hypoxia, including decreasing Complex I activity, elevating the nicotinamide adenine dinucleotide (NADH/NAD(+)) ratio and decreasing expression of the O-2-sensitive ion channel, Kv1.5. Knocking down another Fe-S center within Complex I (Ndufs1, NADH [nicotinamide adenine dinucleotide] dehydrogenase [ubiquinone] iron-sulfur protein 1) or other mitochondrial subunits proposed as putative oxygen sensors (Complex III's Rieske Fe-S center and COX4i2 [cytochrome c oxidase subunit 4 isoform 2] in Complex IV) had no effect on hypoxic increases in [Ca2+](i). In vivo, siNdufs2 significantly decreased hypoxia- and rotenone-induced constriction while enhancing phenylephrine-induced constriction. Conclusions: Ndufs2 is essential for oxygen-sensing and HPV.