Deficiency of Ferritin Heavy-Chain Nuclear Import in Triple A Syndrome Implies Nuclear Oxidative Damage as the Primary Disease Mechanism
Deficiency of Ferritin Heavy-Chain Nuclear Import in Triple A Syndrome Implies Nuclear Oxidative Damage as the Primary Disease Mechanism
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DOI：
10.1210/me.2009-0056
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发表时间：
2009-12-01
影响因子：
--
通讯作者：
Clark, Adrian J. L.
中科院分区：
文献类型：
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作者：
Storr, Helen L.;Kind, Barbara;Clark, Adrian J. L.
Triple A 综合征是一种罕见的常染色体隐性遗传疾病，其特征是 ACTH 抵抗性肾上腺衰竭、流泪症、贲门失弛缓症和进行性神经系统表现。大多数病例与 AAAS 基因突变有关，该基因编码一种新型 60 kDa WD 重复核孔蛋白，即功能未知的无泪腺-贲门失弛缓症-肾上腺皮质功能不全神经系统疾病 (ALADIN)。我们的目的是通过使用细菌双杂交 (B2-H) 技术确定 ALADIN 的相互作用蛋白伙伴来阐明 ALADIN 的功能作用。从编码全长铁蛋白重链蛋白 (FTH1) 的 HeLa S-3 细胞和人小脑 cDNA 文库中鉴定出不相同的 cDNA 片段。这种相互作用通过免疫共沉淀和荧光寿命成像显微镜-荧光共振能量转移研究得到证实。免疫印迹显示来自 3A 患者（已知 AAAS 突变）的成纤维细胞缺乏核 FTH1，表明 FTH1 的核转位有缺陷。转染 FTH1 并通过共聚焦显微镜观察的细胞几乎没有核 FTH1，但当与 AAAS 共转染时，FTH1 在细胞核中很容易可见。因此，当 ALADIN 在这些细胞中共表达时，FTH1 核转位会增强。除了众所周知的铁储存作用外，FTH1 还被证明可以保护细胞核免受氧化损伤。转染AAAS或FTH1或同时转染两种基因可显着减少过氧化氢诱导的神经元细胞凋亡。总而言之，这项工作为 3A 综合征的进展性临床特征提供了一个合理的机制。 （分子内分泌学23：2086-2094，2009）
Triple A syndrome is a rare autosomal recessive disorder characterized by ACTH-resistant adrenal failure, alacrima, achalasia, and progressive neurological manifestations. The majority of cases are associated with mutations in the AAAS gene, which encodes a novel, 60-kDa WD-repeat nuclear pore protein, alacrima-achalasia-adrenal insufficiency neurological disorder (ALADIN) of unknown function. Our aim was to elucidate the functional role of ALADIN by determining its interacting protein partners using the bacterial two-hybrid (B2-H) technique. Nonidentical cDNA fragments were identified from both a HeLa S-3 cell and human cerebellar cDNA library that encoded the full-length ferritin heavy chain protein (FTH1). This interaction was confirmed by both co-immunoprecipitation and fluorescence lifetime imaging microscopy-fluorescence resonance energy transfer studies. Immunoblotting showed that fibroblasts from triple A patients (with known AAAS mutations) lack nuclear FTH1, suggesting that the nuclear translocation of FTH1 is defective. Cells transfected with FTH1 and visualized by confocal microscopy had very little nuclear FTH1, but when cotransfected with AAAS, FTH1 is readily visible in the nuclei. Therefore, FTH1 nuclear translocation is enhanced when ALADIN is coexpressed in these cells. In addition to its well known iron storage role, FTH1 has been shown to protect the nucleus from oxidative damage. Apoptosis of neuronal cells induced by hydrogen peroxide was significantly reduced by transfection of AAAS or by FTH1 or maximally by both genes together. Taken together, this work offers a plausible mechanism for the progressive clinical features of triple A syndrome. (Molecular Endocrinology 23: 2086-2094, 2009)