Intracellular mitochondrial enzyme replacement therapy for heart and skeletalmyopathy in Barth Syndrome

摘要：心脏和骨骼的细胞内线粒体酶替代疗法 Barth综合征中的肌病 巴特综合征是一种X连锁疾病，由他法津编码基因缺陷引起， 一种酰基转移酶，能将心磷脂修饰成四氢杨酸油酰形式，对线粒体来说是必不可少的 呼吸。Barth综合征的临床表现为肌张力低下， 心肌病和中性粒细胞减少症。目前，对于受影响的个人还没有有效的治疗方法。这个 该项目将解决的主要问题是，是否有一种酶替代策略 重组他法津与一种细胞穿透肽相连，可促进对他法津的摄取- 缺陷细胞，恢复心磷脂重塑，抑制线粒体反应异常产生 氧物种(ROS)，恢复正常线粒体呼吸，改善心脏和骨骼肌 改善中性粒细胞减少症。该项目将利用Barth综合征的小鼠模型 来自杰克逊实验室和初步研究，以表征心脏和骨骼的基线功能 肌肉已经做好了。其他重要的里程碑包括产生和提纯 重组他法津蛋白，已被修饰为含有细胞通透性多肽， 验证其进入细胞并纠正心磷脂重塑和线粒体的能力 体外和活体动物的呼吸缺陷。其他项目的发现是他法津缺乏 心肌细胞产生比对照细胞更高水平的ROS，以及外源他法津蛋白 抑制这种过量的ROS生成。在这项提案中，阐明了 设计用于细胞内摄取的重组他法津可以进入细胞并纠正代谢 他法津缺乏的细胞或动物的缺陷将有助于理解这部小说 重组他法津试剂可用于治疗心肌病、骨骼肌病和 Barth综合征患者的中性粒细胞减少。

Abstract: Intracellular mitochondrial enzyme replacement therapy for heart and skeletal myopathy in Barth Syndrome Barth Syndrome is an X-linked disorder resulting from defects in the gene encoding Tafazzin, an acyltransferase that modifies cardiolipin to the tetralinoleoyl form and is essential for mitochondrial respiration. The clinical manifestations of Barth Syndrome include muscular hypotonia, cardiomyopathy and neutropenia. At present, no effective therapy exists for affected individuals. The main issue that this project will address is whether an enzyme replacement strategy in which recombinant tafazzin is linked to a cellular penetrating peptide can promote uptake into tafazzin- deficient cells, restore cardiolipin remodeling, suppress abnormal production of mitochondrial reactive oxygen species (ROS), restore normal mitochondrial respiration, improve heart and skeletal muscle performance and improve neutropenia. This project will utilize a mouse model of Barth Syndrome from Jackson laboratories and initial studies to characterize baseline function in heart and skeletal muscle have been done. Other significant milestones include generation and purification of recombinant tafazzin protein that has been modified to contain a cellular permeability peptide, along with verification of its ability to enter cells and correct both cardiopin remodeling and mitochondrial respiration defects in vitro and in live animals. Other project findings are that tafazzin-deficient myocytes produce ROS at higher levels than control cells, and that exogenous tafazzin protein suppresses this excess ROS generation. In this proposal, elucidation of mechanisms by which recombinant tafazzin engineered for intracellular uptake can enter cells and correct the metabolic defects in tafazzin-deficient cells or animals will facilitate understanding of whether this novel recombinant tafazzin reagent can provide a treatment for cardiomyopathy, skeletal myopathy and neutropenia in Barth Syndrome patients.