Abstract：
OBJECTIVE: Adrenal cortisol production occurs through a biosynthetic pathway which depend on NADH and NADPH for energy supply. The mitochondrial respiratory chain and the reactive oxygen species (ROS) detoxification system are therefore important for steroidogenesis. Mitochondrial dysfunction leading to oxidative stress has been implicated in the pathogenesis of several adrenal conditions. Nonetheless, only very few patients with variants in one gene of the ROS detoxification system, Thioredoxin Reductase 2 (TXNRD2), have been described with variable phenotypes.
METHODS: Clinical, genetic, structural, and functional characterization of a novel, biallelic TXNRD2 splice variant.
METHODS: On human biomaterial, we performed whole exome sequencing to identify and RNA analysis to characterize the specific TXNRD2 splice variant. Amino acid conservation analysis and protein structure modeling were performed in silico. Using patient\'s fibroblast-derived human induced pluripotent stem cells, we generated adrenal-like cells (iALC) to study the impact of wild-type (WT) and mutant TXNRD2 on adrenal steroidogenesis and ROS production.
RESULTS: The patient had a complex phenotype of primary adrenal insufficiency (PAI), combined with genital, ophthalmological, and neurological features. He carried a homozygous splice variant c.1348-1G > T in TXNRD2 which leads to a shorter protein lacking the C-terminus and thereby affecting homodimerization and flavin adenine dinucleotide binding. Patient-derived iALC showed a loss of cortisol production with overall diminished adrenal steroidogenesis, while ROS production was significantly increased.
CONCLUSIONS: Lack of TXNRD2 activity for mitochondrial ROS detoxification affects adrenal steroidogenesis and predominantly cortisol production.
METHODS: Clinical, genetic, structural, and functional characterization of a novel, biallelic TXNRD2 splice variant.
METHODS: On human biomaterial, we performed whole exome sequencing to identify and RNA analysis to characterize the specific TXNRD2 splice variant. Amino acid conservation analysis and protein structure modeling were performed in silico. Using patient\'s fibroblast-derived human induced pluripotent stem cells, we generated adrenal-like cells (iALC) to study the impact of wild-type (WT) and mutant TXNRD2 on adrenal steroidogenesis and ROS production.
RESULTS: The patient had a complex phenotype of primary adrenal insufficiency (PAI), combined with genital, ophthalmological, and neurological features. He carried a homozygous splice variant c.1348-1G > T in TXNRD2 which leads to a shorter protein lacking the C-terminus and thereby affecting homodimerization and flavin adenine dinucleotide binding. Patient-derived iALC showed a loss of cortisol production with overall diminished adrenal steroidogenesis, while ROS production was significantly increased.
CONCLUSIONS: Lack of TXNRD2 activity for mitochondrial ROS detoxification affects adrenal steroidogenesis and predominantly cortisol production.
摘要：
目的：肾上腺皮质醇的产生是通过生物合成途径进行的，该途径依赖于NADH和NADPH的能量供应。因此，线粒体呼吸链和活性氧（ROS）解毒系统对于类固醇生成很重要。导致氧化应激的线粒体功能障碍与几种肾上腺疾病的发病机理有关。尽管如此，只有极少数患者在ROS解毒系统的一个基因中变异，硫氧还蛋白还原酶2（TXNRD2），已被描述为具有可变的表型。
方法：临床，遗传,一种新颖的结构和功能表征，双等位基因TXNRD2剪接变体。
方法：关于人类生物材料，我们进行了全外显子组测序以鉴定和RNA分析以表征特定的TXNRD2剪接变体.在计算机中进行氨基酸保守性分析和蛋白质结构建模。使用患者的成纤维细胞来源的人诱导多能干细胞，我们产生了肾上腺样细胞(iALC),以研究野生型(WT)和突变型TXNRD2对肾上腺类固醇生成和ROS产生的影响.
结果：患者具有原发性肾上腺功能不全（PAI）的复杂表型，结合生殖器，眼科和神经系统的特点。他在TXNRD2中携带纯合剪接变体c.1348-1G>T，导致缺乏C末端的较短蛋白质，从而影响同源二聚化和FAD结合。患者来源的iALC显示皮质醇产生减少，肾上腺类固醇生成总体减少，而ROS产量显著增加。
结论：线粒体ROS解毒的TXNRD2活性缺乏会影响肾上腺类固醇生成和主要的皮质醇生成。
方法：临床，遗传,一种新颖的结构和功能表征，双等位基因TXNRD2剪接变体。
方法：关于人类生物材料，我们进行了全外显子组测序以鉴定和RNA分析以表征特定的TXNRD2剪接变体.在计算机中进行氨基酸保守性分析和蛋白质结构建模。使用患者的成纤维细胞来源的人诱导多能干细胞，我们产生了肾上腺样细胞(iALC),以研究野生型(WT)和突变型TXNRD2对肾上腺类固醇生成和ROS产生的影响.
结果：患者具有原发性肾上腺功能不全（PAI）的复杂表型，结合生殖器，眼科和神经系统的特点。他在TXNRD2中携带纯合剪接变体c.1348-1G>T，导致缺乏C末端的较短蛋白质，从而影响同源二聚化和FAD结合。患者来源的iALC显示皮质醇产生减少，肾上腺类固醇生成总体减少，而ROS产量显著增加。
结论：线粒体ROS解毒的TXNRD2活性缺乏会影响肾上腺类固醇生成和主要的皮质醇生成。
