Ferredoxin 1b (Fdx1b) Is the Essential Mitochondrial Redox Partner for Cortisol Biosynthesis in Zebrafish.
Ferredoxin 1b (Fdx1b) Is the Essential Mitochondrial Redox Partner for Cortisol Biosynthesis in Zebrafish.
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DOI：
10.1210/en.2015-1480
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发表时间：
2016-03
期刊：
影响因子：
4.8
通讯作者：
Krone N
中科院分区：
文献类型：
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作者：
Griffin A;Parajes S;Weger M;Zaucker A;Taylor AE;O'Neil DM;Müller F;Krone N
线粒体细胞色素 P450 (CYP) 酶依靠氧化还原伙伴铁氧还蛋白 1 (FDX1) 的电子转移来发挥催化活性。类固醇生成的关键步骤需要线粒体 CYP 酶和 FDX1。体外研究了超过 30 种铁氧还蛋白突变；然而，在人类中尚未发现自发发生的突变，这使得 FDX1 对整个生物体类固醇生成的影响很大程度上未知。斑马鱼是研究人类类固醇生成的重要模型，因为它们具有相似的类固醇产物和内分泌组织。本研究旨在通过使用斑马鱼来表征铁氧还蛋白对体内类固醇生成能力的影响。斑马鱼具有重复的铁氧还蛋白旁系同源物：fdx1 和 fdx1b。尽管 fdx1 在整个发育过程中和大多数组织中都可以观察到，但 fdx1b 在斑马鱼肾间腺（与哺乳动物肾上腺相对应）发育后表达。此外，fdx1b 仅限于成人类固醇生成组织，例如肾间、性腺和大脑，这表明 fdx1b 与类固醇生成 CYP 酶相互作用。通过使用类转录激活因子效应核酸酶，我们生成了 fdx1b 突变斑马鱼系。 fdx1b 基因被破坏的幼虫在形态上并不显眼。然而，通过液相色谱串联质谱法进行的类固醇激素分析显示，fdx1b 突变体无法合成糖皮质激素。此外，这些突变体的下丘脑-垂体-肾间轴上调，并表现出暗光适应能力的改变，表明皮质醇信号传导受损。反义吗啉敲低证实 Fdx1b 是皮质醇从头生物合成所必需的。总之，通过使用斑马鱼，我们构建了铁氧还蛋白敲除模型系统，该系统首次证明了线粒体氧化还原调节对体内糖皮质激素生物合成的影响。
Mitochondrial cytochrome P450 (CYP) enzymes rely on electron transfer from the redox partner ferredoxin 1 (FDX1) for catalytic activity. Key steps in steroidogenesis require mitochondrial CYP enzymes and FDX1. Over 30 ferredoxin mutations have been explored in vitro; however, no spontaneously occurring mutations have been identified in humans leaving the impact of FDX1 on steroidogenesis in the whole organism largely unknown. Zebrafish are an important model to study human steroidogenesis, because they have similar steroid products and endocrine tissues. This study aimed to characterize the influence of ferredoxin on steroidogenic capacity in vivo by using zebrafish. Zebrafish have duplicate ferredoxin paralogs: fdx1 and fdx1b. Although fdx1 was observed throughout development and in most tissues, fdx1b was expressed after development of the zebrafish interrenal gland (counterpart to the mammalian adrenal gland). Additionally, fdx1b was restricted to adult steroidogenic tissues, such as the interrenal, gonads, and brain, suggesting that fdx1b was interacting with steroidogenic CYP enzymes. By using transcription activator-like effector nucleases, we generated fdx1b mutant zebrafish lines. Larvae with genetic disruption of fdx1b were morphologically inconspicuous. However, steroid hormone analysis by liquid chromatography tandem mass spectrometry revealed fdx1b mutants failed to synthesize glucocorticoids. Additionally, these mutants had an up-regulation of the hypothalamus-pituitary-interrenal axis and showed altered dark-light adaptation, suggesting impaired cortisol signaling. Antisense morpholino knockdown confirmed Fdx1b is required for de novo cortisol biosynthesis. In summary, by using zebrafish, we generated a ferredoxin knockout model system, which demonstrates for the first time the impact of mitochondrial redox regulation on glucocorticoid biosynthesis in vivo.