Mechanisms of DUX4 mediated FSHD pathology

DUX4 介导的 FSHD 病理机制

• 批准号: 10554358
• 负责人: Peter L Jones
• 金额: $ 60.52万
• 依托单位: UNIVERSITY OF NEVADA RENO
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-03 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10554358
• 关键词: 4q35; ASH1L gene; Address; Adult; Affect; Age; Animal Model; Animal Muscular Dystrophy; Artificial Human Chromosomes; Automobile Driving; Biological; Biological Assay; Cells; Chromatin; Chromatin Remodeling Factor; Chromosomes; Clinical; Clustered Regularly Interspaced Short Palindromic Repeats; Complex; D4Z4; Development; Disease; Distal; Engraftment; Enhancers; Epigenetic Process; Facioscapulohumeral Muscular Dystrophy; Female; Funding; Gene Expression; Gene Expression Profile; Genes; Genetic; Genome; Goals; Health; Human; Mediating; Modeling; Mus; Muscle; Muscle Cells; Muscle Development; Muscle Fibers; Myoblasts; Myopathy; Natural regeneration; Pathogenesis; Pathogenicity; Pathology; Pathway interactions; Patients; Proteins; Regulation; Relaxation; Reporter; Repression; Role; SMARCA5 gene; Severities; Skeletal Muscle; Specificity; Testing; Therapeutic; Therapeutic Intervention; Tissues; Transgenic Organisms; Validation; Xenograft procedure; causal variant; diagnostic assay; effective therapy; in vivo; insight; knock-down; male; mouse model; new therapeutic target; novel; prevent; targeted treatment; therapeutic development; therapeutic target; translational potential; virulence gene

SUMMARY Facioscapulohumeral Muscular Dystrophy (FSHD) is one of the most prevalent myopathies affecting males and females of all ages, and currently there is no cure or therapeutic intervention available. The long-term goal of this project is to determine the epigenetic mechanisms leading to pathogenic gene expression in FSHD, and identify regulatory components that are viable targets for therapeutic development. FSHD is a complex genetic and epigenetic disease caused by chromatin relaxation of the D4Z4 macrosatellite repeat array at chromosome 4q35, which leads to aberrant expression of the DUX4 gene from the distal-most repeat unit. The DUX4 protein, in turn, activates a host of genes normally expressed in early development, which cause pathology when mis-expressed in adult skeletal muscle. This established model of FSHD pathogenesis has stimulated the search for DUX4- based therapeutic targets, including approaches to block DUX4 expression. While normal mechanisms of D4Z4 repression have been well-characterized, very little is known about the factors and pathways responsible for facilitating aberrant activation of DUX4. Previously, we showed that the degree and stability of epigenetic dysregulation at the FSHD-associated 4q35 locus is the key determinant for DUX4 expression, clinical presentation, and severity of FSHD pathology. Thus, targeting epigenetic dysregulation in FSHD is a potentially powerful therapeutic avenue. Such an approach would be greatly aided by a better understanding of the factors facilitating DUX4 expression, each of which represents a potential target for therapeutic inhibition. In a candidate-based screen, we identified several epigenetic regulators with druggable domains that function as novel activators of DUX4. Here, we will characterize these epigenetic facilitators of DUX4 expression and validate their potential as therapeutic targets in FSHD. We will determine the global effects of reducing the expression of these factors on skeletal muscle health and development using primary patient cells and novel animal models. Finally, we will test the translational potential of inhibiting these DUX4 regulators in an FSHD human xenograft mouse model derived from FSHD patient myoblasts with their endogenous D4Z4 arrays. DUX4 regulators will be inhibited by CRISPR inhibition and assayed for specificity. Successful completion of this project will provide key insights into the mechanisms of epigenetic dysregulation in FSHD and validate the translational potential of novel therapeutic targets in vivo.

概括 面肩肱型肌营养不良症 (FSHD) 是最常见的肌病之一，影响 所有年龄段的男性和女性，目前尚无可用的治愈或治疗干预措施。这 该项目的长期目标是确定导致致病基因的表观遗传机制 FSHD 中的表达，并确定作为治疗可行靶标的调节成分 发展。 FSHD 是一种复杂的遗传和表观遗传疾病，由染色质松弛引起 染色体 4q35 上的 D4Z4 大卫星重复阵列，导致异常表达 来自最远端重复单元的 DUX4 基因。 DUX4 蛋白反过来激活一系列基因 通常在早期发育中表达，当在成人中错误表达时会导致病理 骨骼肌。这种 FSHD 发病机制的建立模型刺激了对 DUX4- 的研究 基于治疗靶点，包括阻断 DUX4 表达的方法。虽然正常 D4Z4 抑制机制已得到充分表征，但对其因素知之甚少 以及负责促进 DUX4 异常激活的途径。之前，我们表明 FSHD 相关 4q35 位点表观遗传失调的程度和稳定性是关键 DUX4 表达、临床表现和 FSHD 病理严重程度的决定因素。因此， 针对 FSHD 的表观遗传失调是一种潜在的强大治疗途径。这样一个 更好地理解促进 DUX4 的因素将大大有助于该方法 表达，每个都代表治疗抑制的潜在靶标。在基于候选人的 筛选后，我们发现了几种具有可药物结构域的表观遗传调节因子，这些调节因子具有新颖的功能 DUX4 的激活剂。在这里，我们将描述 DUX4 表达的这些表观遗传促进因子 验证它们作为 FSHD 治疗靶点的潜力。我们将确定全球影响 使用初级方法减少这些因素对骨骼肌健康和发育的影响 患者细胞和新型动物模型。最后，我们将测试抑制这些的转化潜力 源自 FSHD 患者成肌细胞的 FSHD 人类异种移植小鼠模型中的 DUX4 调节剂 及其内源性 D4Z4 阵列。 DUX4 调节因子将被 CRISPR 抑制所抑制 测定特异性。该项目的成功完成将为我们提供重要的见解 FSHD 表观遗传失调的机制并验证新型药物的转化潜力 体内治疗靶点。