Division of Genetics and Genomics at Boston Children's Hospital, Boston, Massachusetts, USA.
Department of Pediatrics, Division of Neurology at the University of Alabama at Birmingham and Children's of Alabama, Birmingham, Alabama, USA.
JCI Insight. 2018 Sep 20;3(18). doi: 10.1172/jci.insight.120493.
Zebrafish are a powerful tool for studying muscle function owing to their high numbers of offspring, low maintenance costs, evolutionarily conserved muscle functions, and the ability to rapidly take up small molecular compounds during early larval stages. Fukutin-related protein (FKRP) is a putative protein glycosyltransferase that functions in the Golgi apparatus to modify sugar chain molecules of newly translated proteins. Patients with mutations in the FKRP gene can have a wide spectrum of clinical symptoms with varying muscle, eye, and brain pathologies depending on the location of the mutation in the FKRP protein. Patients with a common L276I FKRP mutation have mild adult-onset muscle degeneration known as limb-girdle muscular dystrophy 2I (LGMD2I), whereas patients with more C-terminal pathogenic mutations develop the severe Walker-Warburg syndrome (WWS)/muscle-eye-brain (MEB) disease. We generated fkrp-mutant zebrafish that phenocopy WWS/MEB pathologies including severe muscle breakdowns, head malformations, and early lethality. We have also generated a milder LGMD2I-model zebrafish via overexpression of a heat shock-inducible human FKRP (L276I) transgene that shows milder muscle pathology. Screening of an FDA-approved drug compound library in the LGMD2I zebrafish revealed a strong propensity towards steroids, antibacterials, and calcium regulators in ameliorating FKRP-dependent pathologies. Together, these studies demonstrate the utility of the zebrafish to both study human-specific FKRP mutations and perform compound library screenings for corrective drug compounds to treat muscular dystrophies.
斑马鱼是研究肌肉功能的有力工具，因为它们具有繁殖力强、维护成本低、肌肉功能进化保守以及在早期幼虫阶段能够快速吸收小分子化合物的特点。Fukutin 相关蛋白（FKRP）是一种假定的蛋白糖基转移酶，在高尔基体内发挥作用，修饰新翻译蛋白的糖链分子。FKRP 基因突变的患者可能具有广泛的临床表现，肌肉、眼睛和大脑的病变程度取决于 FKRP 蛋白中突变的位置。携带常见 L276I FKRP 突变的患者具有轻度成人发病的肌肉退行性变，称为肢带型肌营养不良症 2I（LGMD2I），而携带更靠 C 端致病性突变的患者则会发展为严重的 Walker-Warburg 综合征（WWS）/肌肉眼脑（MEB）疾病。我们生成了 FKRP 突变的斑马鱼，其表型与 WWS/MEB 病理相似，包括严重的肌肉分解、头部畸形和早期致死性。我们还通过过表达热休克诱导的人类 FKRP（L276I）转基因，生成了一种更轻微的 LGMD2I 模型斑马鱼，该模型显示出更轻微的肌肉病理学。在 LGMD2I 斑马鱼中对 FDA 批准的药物化合物库进行筛选，结果表明类固醇、抗菌药和钙调节剂在改善 FKRP 依赖性病变方面具有很强的倾向。总之，这些研究表明，斑马鱼既可以用于研究人类特异性 FKRP 突变，也可以用于进行化合物库筛选，以寻找治疗肌肉营养不良的矫正药物化合物。
