1 Unit of Molecular Neurogenetics, Foundation IRCCS Neurological Institute C. Besta, Milan, Italy.
Brain. 2014 Jan;137(Pt 1):57-68. doi: 10.1093/brain/awt325. Epub 2013 Dec 6.
Pantothenate kinase-associated neurodegeneration, caused by mutations in the PANK2 gene, is an autosomal recessive disorder characterized by dystonia, dysarthria, rigidity, pigmentary retinal degeneration and brain iron accumulation. PANK2 encodes the mitochondrial enzyme pantothenate kinase type 2, responsible for the phosphorylation of pantothenate or vitamin B5 in the biosynthesis of co-enzyme A. A Pank2 knockout (Pank2(-/-)) mouse model did not recapitulate the human disease but showed azoospermia and mitochondrial dysfunctions. We challenged this mouse model with a low glucose and high lipid content diet (ketogenic diet) to stimulate lipid use by mitochondrial beta-oxidation. In the presence of a shortage of co-enzyme A, this diet could evoke a general impairment of bioenergetic metabolism. Only Pank2(-/-) mice fed with a ketogenic diet developed a pantothenate kinase-associated neurodegeneration-like syndrome characterized by severe motor dysfunction, neurodegeneration and severely altered mitochondria in the central and peripheral nervous systems. These mice also showed structural alteration of muscle morphology, which was comparable with that observed in a patient with pantothenate kinase-associated neurodegeneration. We here demonstrate that pantethine administration can prevent the onset of the neuromuscular phenotype in mice suggesting the possibility of experimental treatment in patients with pantothenate kinase-associated neurodegeneration.
泛酸激酶相关神经退行性变是一种常染色体隐性疾病,由 PANK2 基因突变引起,其特征为肌张力障碍、构音障碍、僵硬、色素性视网膜变性和脑铁蓄积。PANK2 基因编码线粒体酶泛酸激酶 2,负责辅酶 A 生物合成中泛酸或维生素 B5 的磷酸化。Pank2 基因敲除(Pank2(-/-))小鼠模型不能重现人类疾病,但表现为无精子症和线粒体功能障碍。我们用低糖和高脂肪含量的饮食(生酮饮食)来刺激线粒体β氧化利用脂肪来挑战这个小鼠模型。在辅酶 A 短缺的情况下,这种饮食可能会引起生物能量代谢的普遍损伤。只有用生酮饮食喂养的 Pank2(-/-) 小鼠才会发展出一种类似于泛酸激酶相关神经退行性变的综合征,其特征为严重的运动功能障碍、神经退行性变和中枢及外周神经系统中严重改变的线粒体。这些小鼠还表现出肌肉形态的结构改变,与泛酸激酶相关神经退行性变患者观察到的改变相当。我们在此证明,泛硫乙胺的给药可以预防小鼠神经肌肉表型的发生,这表明在泛酸激酶相关神经退行性变患者中进行实验治疗的可能性。