Three-model platform for understanding DMD epigenetic mechanisms and advancing small molecule therapies

用于了解 DMD 表观遗传机制和推进小分子疗法的三模型平台

• 批准号: 10578675
• 负责人: David Lee Mack
• 金额: $ 55万
• 依托单位: SEATTLE CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-04 至 2025-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10578675
• 关键词: Adrenal Cortex Hormones; Affect; Aftercare; Biological Models; Birth; Cell Line; Cells; Chromatin; Clinical Trials; Combined Modality Therapy; Defect; Development; Disease; Drug usage; Duchenne muscular dystrophy; Dystrophin; Effectiveness; Embryo; Epigenetic Process; Event; Face; Functional disorder; Future; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Genomics; Goals; Histone Deacetylase Inhibitor; Human; Human Cell Line; Knowledge; Libraries; Maps; Modeling; Mus; Muscle; Muscle function; Muscular Dystrophies; Mutation; Myocardium; Myopathy; Neuromuscular Diseases; Outcome Measure; Pathologic; Pathology; Patients; Pharmacotherapy; Phenotype; Positioning Attribute; Pre-Clinical Model; Process; Progressive Disease; Public Health; Rattus; Research; Role; Safety; Skeletal Muscle; Testing; Transcriptional Regulation; Validation; Work; Zebrafish; chromatin modification; clinically relevant; disease-causing mutation; drug discovery; drug efficacy; epigenetic drug; fetal; functional outcomes; gene therapy; improved; induced pluripotent stem cell; insight; male; muscular structure; myogenesis; novel; novel therapeutics; pharmacologic; preclinical evaluation; restoration; screening; side effect; small molecule; standard of care; targeted treatment; transcriptome

PROJECT SUMMARY Duchenne muscular dystrophy (DMD) is a severe degenerative muscle disease caused by mutations in the DMD gene, which encodes dystrophin. The current standard of care, corticosteroid treatment, delays the progression of muscle dysfunction but has serious side effects. DMD gene therapy and gene editing approaches are promising but face many challenges. Pharmacological approaches are being identified that could benefit DMD by modulating pathological mechanisms independent of the dystrophin mutation. However, many small molecule therapies have had difficulties showing efficacy while progressing through DMD clinical trials, possibly due to inadequate preclinical evaluation or to targeting mechanisms too late in the disease process. Although DMD is a progressive disease, there is evidence for early, embryonic- and fetal-stage defects in myogenesis and gene expression in DMD. In particular, our preliminary studies have identified one of the earliest known DMD phenotypes: a novel transcriptional trajectory of DMD human induced pluripotent stem cells (hiPSCs) undergoing myogenesis. By understanding how these early myogenic and transcriptional defects initiate and how they drive DMD pathology, we may be better positioned to identify and utilize DMD therapies. The hypothesis of this proposal is that epigenetic drugs, small molecules that target chromatin modifications and transcriptional regulation, can ameliorate early DMD transcriptional defects as well as improve downstream DMD pathology. Certain histone deacetylase inhibitors (HDACi) have shown promise for DMD in mice, zebrafish, and recent clinical trials. However, beyond these HDACi, epigenetic drugs have not been broadly and systematically studied for their efficacy and safety to treat DMD. The goals of this proposal are to identify novel epigenetic small molecules that are beneficial for DMD, by demonstrating effectiveness in multiple DMD models, and, in parallel, to better characterize the disrupted transcriptional and epigenetic mechanisms underlying DMD. We propose three Aims. First, we will identify the classes of epigenetic small molecules that improve the DMD phenotype, by screening an epigenetic drug library in dmd zebrafish. Our preliminary studies have already identified novel epigenetic drugs that rescue dmd zebrafish. Second, through single-cell genomics on hiPSC-derived DMD skeletal muscle, we will generate maps of transcriptome and chromatin packaging defects during the initiation and progression of DMD. We will test whether epigenetic drugs correct the novel transcriptional dysregulation phenotype, as well as functional deficits, that we have identified in hiPSC-derived DMD muscle. Third, we will evaluate epigenetic drugs for efficacy and safety in the DMD rat, assessing clinically relevant functional outcomes in skeletal and cardiac muscle. This project will provide novel basic scientific insight into the early epigenetic dysregulation occurring in DMD. The long-term impact will be the development of a three-model platform, zebrafish, rat and hiPSC lines, for DMD drug discovery and mechanistic and functional validation, taking advantage of each model system.

项目摘要 杜氏肌营养不良症（DMD）是一种严重的退行性肌肉疾病所造成的突变在DMD 基因，编码肌营养不良蛋白。目前的标准治疗，皮质类固醇治疗，延迟进展 但有严重的副作用DMD基因治疗和基因编辑方法 前景广阔，但面临诸多挑战。药理学方法正在确定，可能有利于DMD 通过调节独立于肌营养不良蛋白突变的病理机制。然而，许多小分子 治疗在DMD临床试验中难以显示疗效，这可能是由于 临床前评估不足或靶向机制在疾病过程中太晚。虽然DMD是 作为一种进行性疾病，有证据表明早期、胚胎期和胎儿期肌肉发生和基因缺陷， 在DMD中表达。特别是，我们的初步研究已经确定了已知最早的DMD之一， 表型：DMD人诱导多能干细胞（hiPSC）经历的新转录轨迹 肌生成通过了解这些早期肌源性和转录缺陷如何启动以及它们如何驱动 DMD病理学，我们可能更好地定位，以确定和利用DMD疗法。这个假设 一项建议是，表观遗传药物，靶向染色质修饰和转录的小分子， 调控，可以改善早期DMD转录缺陷以及改善下游DMD病理。 某些组蛋白去乙酰化酶抑制剂（HDACi）已经显示出对小鼠、斑马鱼和最近的DMD的前景。 临床试验然而，除了这些HDACi，表观遗传药物尚未得到广泛和系统的研究 治疗DMD的有效性和安全性。这项提案的目标是确定新的表观遗传小 通过在多个DMD模型中证明有效性，对DMD有益的分子，并且，并行地， 以更好地表征DMD基础的被破坏的转录和表观遗传机制。我们提出 三个目标。首先，我们将通过以下方式鉴定改善DMD表型的表观遗传小分子的类别： 在DMD斑马鱼中筛选表观遗传药物文库。我们的初步研究已经发现了 拯救DMD斑马鱼的表观遗传药物第二，通过单细胞基因组学对hiPSC衍生的DMD 在骨骼肌中，我们将在启动期间生成转录组和染色质包装缺陷的图谱 DMD的进展。我们将测试表观遗传药物是否能纠正新的转录失调 表型，以及我们已经在hiPSC衍生的DMD肌肉中鉴定的功能缺陷。三是 评估表观遗传药物在DMD大鼠中的有效性和安全性，评估临床相关功能 骨骼肌和心肌的结果。该项目将提供新的基本科学见解， DMD中发生的表观遗传失调。长远的影响将是发展一个三模式 平台，斑马鱼，大鼠和hiPSC系，用于DMD药物发现和机制和功能验证， 利用每个模型系统。