MICA: Strategy for heart repair in Duchenne Muscular Dystrophy (DMD) using genetically engineered autologous Mesoangioblasts

MICA：利用基因工程自体中成血管细胞修复杜氏肌营养不良症 (DMD) 的心脏的策略

• 批准号: MR/X00466X/1
• 负责人: Francesco Galli
• 金额: $ 51.79万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FX00466X%2F1
• 关键词: MICA; Strategy; heart; repair; Duchenne

The NHS official website indicates that around 70,000 people have Muscular Dystrophy (MD) or a related condition in the UK. Duchenne Muscular Dystrophy (DMD) is the most common and one of the most severe forms of MD. DMD is an inherited disease due to lack of expression of the dystrophin protein, causing a progressive waste of skeletal muscle which lead to progressive loss of ambulation, muscle weakness and muscle wasting in children. In the most severe cases, also heart muscle cells are affected, and this result in heart failure, the most common cause of premature death in DMD patients. All MDs still lack an effective therapy, even though administration of steroids (although with severe adverse effects), corrective surgery, assisted ventilation and drugs to support cardiac function have improved both the duration and the quality of life for patients.Many approaches based on either stem cells or gene therapy have entered clinical experimentation with the aim of repairing DMD heart, but none has reached significant clinical efficacy. The limited success of these therapies is due both to the difficulties of delivering the treatment to the heart and to the activation of the immune system of the patients towards donor cells or viral vectors. To overcome these limitations, I have developed a cell mediated exon skipping strategy, for skeletal muscle, currently being tested in a clinical trial in Manchester (EudrAct n.2019-001825-28), based upon transplantation of autologous Mesoangioblasts (Mabs), which are vessel-associated myogenic progenitors. Mabs are genetically corrected using a lentivector expressing a small nuclear RNA (snRNA) designed to induce exon-skipping on dystrophin exon 51 and to generate a short but functional version of dystrophin. The novelty of this approach is based on the ability of snRNA to diffuse along the regenerating muscle fibre and then correcting the resident dystrophic neighbouring nuclei inducing exon skipping. However, Mabs can be used only for the treatment of skeletal muscle as they cannot naturally differentiate into cardiac muscle: for this reason, the heart of the MD patients would remain untreated. In this project I will address this problem. It is well known that fibroblasts can be converted to cardiac muscle cells but, in comparison with Mabs, they cannot be delivered systematically, due to their inability to cross the vessel walls. This makes cardiac-converted fibroblasts good candidates to treat only localised lesions like myocardial infarct but not to treat progressive and widespread cardiomyopathies. My preliminary data show that Mabs can be converted to cardiomyocytes by transient over-expression of specific cardiac related genes in around 10-15 days. I therefore hypothesize that this time window will allow to deliver these Mabs-converted cardiomyocytes by cardiac catheterization in the whole heart. This project aims to evaluate the structural and functional amelioration of the heart in a mouse model of DMD after transplantation of Mabs-converted cardiomyocytes. Moreover, I will quantify the extent of the fusion of genetically corrected Mabs-converted cardiomyocytes with resident cardiomyocytes and subsequently the rate of correction, by exon-skipping, in the neighbouring nuclei quantifying the amount of dystrophin produced.The core element of this strategy is already in clinical experimentation for DMD skeletal muscle but not for the heart. This project will test the applicability of the cell mediated exon-skipping strategy to the heart. The succesful outcome of this project, demonstrating the efficacy of this strategy, will lead the way for a future clinical testing of this strategy in the heart of DMD patients and in heart diseases in general.

NHS 官方网站显示，英国约有 7 万人患有肌营养不良症 (MD) 或相关病症。杜氏肌营养不良症 (DMD) 是最常见也是最严重的 MD 形式之一。 DMD 是一种遗传性疾病，由于抗肌营养不良蛋白表达缺乏，导致骨骼肌逐渐萎缩，进而导致儿童逐渐丧失行走能力、肌无力和肌肉萎缩。在最严重的情况下，心肌细胞也会受到影响，从而导致心力衰竭，这是 DMD 患者过早死亡的最常见原因。尽管使用类固醇（尽管有严重的副作用）、矫正手术、辅助通气和支持心脏功能的药物已经改善了患者的生存时间和生活质量，但所有MD仍然缺乏有效的治疗方法。许多基于干细胞或基因治疗的方法已进入临床试验，旨在修复DMD心脏，但没有一种达到显着的临床疗效。这些疗法的成功有限是由于难以将治疗传递到心脏以及激活患者对供体细胞或病毒载体的免疫系统。为了克服这些限制，我开发了一种针对骨骼肌的细胞介导的外显子跳跃策略，目前正在曼彻斯特的一项临床试验中进行测试（EudrAct n.2019-001825-28），该策略基于自体中成血管细胞（Mab）（血管相关的肌源性祖细胞）的移植。使用表达小核 RNA (snRNA) 的慢载体对 Mab 进行基因校正，该慢病毒载体旨在诱导肌营养不良蛋白外显子 51 上的外显子跳跃，并生成简短但有功能的肌营养不良蛋白版本。这种方法的新颖性是基于 snRNA 沿着再生肌纤维扩散的能力，然后纠正诱导外显子跳跃的常驻营养不良的邻近核。然而，单克隆抗体只能用于治疗骨骼肌，因为它们不能自然分化为心肌：因此，MD 患者的心脏将得不到治疗。在这个项目中我将解决这个问题。众所周知，成纤维细胞可以转化为心肌细胞，但与单克隆抗体相比，由于它们无法穿过血管壁，因此无法系统地递送。这使得心脏转化的成纤维细胞成为仅治疗心肌梗塞等局部病变的良好候选者，但不能治疗进行性和广泛的心肌病。我的初步数据显示，Mab 可以通过特定心脏相关基因的瞬时过度表达在大约 10-15 天内转化为心肌细胞。因此，我假设这个时间窗口将允许通过心导管插入术在整个心脏中递送这些单克隆抗体转化的心肌细胞。该项目旨在评估 DMD 小鼠模型移植 Mabs 转化的心肌细胞后心脏结构和功能的改善情况。此外，我将量化基因校正的 Mabs 转化的心肌细胞与常驻心肌细胞的融合程度，以及随后通过外显子跳跃在邻近细胞核中量化抗肌萎缩蛋白产生量的校正率。该策略的核心要素已经在 DMD 骨骼肌的临床实验中，但尚未在心脏的临床实验中。该项目将测试细胞介导的外显子跳跃策略对心脏的适用性。该项目的成功结果证明了该策略的有效性，将为未来对该策略在 DMD 患者心脏和一般心脏病中的临床测试开辟道路。