AAV-based TCAP delivery rescues mitochondria dislocation in limb-girdle muscular dystrophy R7.

IF 10.6 1区 医学 Q1 CLINICAL NEUROLOGY
Brain Pub Date : 2024-10-28 DOI:10.1093/brain/awae351
Xiaoqing Lv, Shuangwu Liu, Xi Li, He Lv, Kai Shao, Sushan Luo, Dandan Zhao, Chuanzhu Yan, Pengfei Lin
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引用次数: 0

Abstract

Limb-girdle muscular dystrophy R7 is a rare genetic disease caused by homozygous or compound heterozygous variants in the titin-cap (TCAP) gene that results in the absence of the protein telethonin. The primary pathological features of limb-girdle muscular dystrophy R7 are fiber size variation, nuclear centralization, and abnormal mitochondrial distribution. The mechanisms underlying this disease are unclear, and there is currently no specific treatment for limb-girdle muscular dystrophy R7. This study established a Tcap-deficient mouse model to explore the disease mechanism of mitochondria dislocation and potential therapeutic strategies. We use methods such as proteomics, immunofluorescence, histopathological staining, and western blotting to explore the mechanism of mitochondrial dislocation. Moreover, in the quest for a prospective therapeutic intervention for this disorder, the adeno-associated virus serotype 2/9 was employed to deliver the Tcap gene into the muscles of these mice, facilitating preclinical experimentation. After 2 months and 7 months, the muscular phenotype was evaluated and selected mice were humanely euthanized for subsequent molecular and histological analysis. The phenotype of Tcap-/- mice mimicked that observed in individuals diagnosed with limb-girdle muscular dystrophy R7. This study elucidated the mechanism of mitochondrial dislocation in limb-girdle muscular dystrophy R7. Through our in vitro experiments, we discovered that telethonin aids in preserving the integrity of desmin by preventing truncation at the N-terminus. Additionally, telethonin combined with desmin and colocalized at the Z-disc. Research has shown that the Tcap gene plays a crucial role in controlling the desmin cytoskeleton organization. The absence of telethonin leads to a collapsed desmin cytoskeleton. This causes disorganization of the mitochondrial network, leading to mitochondrial dysfunction. In addition, the study investigated the efficacy of adeno-associated virus (AAV)-mediated Tcap replacement in Tcap-/- mice. By intramuscular delivery of AAV, we observed dramatic improvements in muscle phenotype, muscle pathology, CK levels, muscle magnetic resonance imaging, mitochondrial network organization, and mitochondrial function. The results of this study demonstrated that telethonin deficiency led to desmin cytoskeleton collapse that caused mitochondrial dislocation. AAV-mediated replacement therapy could be a promising safe and efficient treatment option for limb-girdle muscular dystrophy R7. The study highlights the potential of AAV-mediated replacement therapy for specific types of limb-girdle muscular dystrophy.

基于AAV的TCAP递送可挽救肢腰肌营养不良症R7的线粒体错位。
肢腰肌营养不良症 R7 是一种罕见的遗传病,由 titin-cap(TCAP)基因的同源变异或复合杂合变异引起,导致蛋白质 telethonin 的缺失。肢腰肌营养不良症 R7 的主要病理特征是纤维大小变异、核集中和线粒体分布异常。这种疾病的发病机制尚不清楚,目前也没有治疗肢腰肌营养不良症R7的特效药物。本研究建立了一个Tcap缺陷小鼠模型,以探索线粒体错位的疾病机制和潜在的治疗策略。我们采用蛋白质组学、免疫荧光、组织病理学染色和 Western 印迹等方法来探索线粒体脱位的机制。此外,为了寻找治疗这种疾病的前瞻性干预措施,我们还采用了 2/9 血清型腺相关病毒将 Tcap 基因注入这些小鼠的肌肉,从而促进了临床前实验。2 个月和 7 个月后,对小鼠的肌肉表型进行评估,并对选定的小鼠实施人道安乐死,以进行后续的分子和组织学分析。Tcap-/-小鼠的表型与被诊断患有肢腰肌营养不良症R7的小鼠的表型相似。这项研究阐明了肢腰肌营养不良症R7线粒体脱位的机制。通过体外实验,我们发现 telethonin 能防止 N 端截断,从而有助于保持 desmin 的完整性。此外,telethonin 还能与 desmin 结合,并在 Z 盘处共定位。研究表明,Tcap 基因在控制 desmin 细胞骨架组织方面起着至关重要的作用。telethonin 的缺失会导致 desmin 细胞骨架坍塌。这会导致线粒体网络紊乱,从而导致线粒体功能障碍。此外,该研究还调查了腺相关病毒(AAV)介导的Tcap置换对Tcap-/-小鼠的疗效。通过肌肉注射 AAV,我们观察到肌肉表型、肌肉病理学、CK 水平、肌肉磁共振成像、线粒体网络组织和线粒体功能都有显著改善。这项研究结果表明,telethonin 缺乏会导致 desmin 细胞骨架崩溃,从而引起线粒体错位。AAV介导的替代疗法可能是治疗肢腰肌营养不良症R7的一种安全有效的治疗方案。该研究强调了AAV介导的替代疗法治疗特定类型肢腰肌营养不良症的潜力。
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来源期刊
Brain
Brain 医学-临床神经学
CiteScore
20.30
自引率
4.10%
发文量
458
审稿时长
3-6 weeks
期刊介绍: Brain, a journal focused on clinical neurology and translational neuroscience, has been publishing landmark papers since 1878. The journal aims to expand its scope by including studies that shed light on disease mechanisms and conducting innovative clinical trials for brain disorders. With a wide range of topics covered, the Editorial Board represents the international readership and diverse coverage of the journal. Accepted articles are promptly posted online, typically within a few weeks of acceptance. As of 2022, Brain holds an impressive impact factor of 14.5, according to the Journal Citation Reports.
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