Improving dystrophin gene therapy through understanding dystrobrevin function

描述(申请人提供)：心脏病是杜氏肌营养不良症(DMD)患者的主要死亡原因。DMD是一种一致致命的疾病，其特征是严重的骨骼肌损伤和心肌病，由dystrophin基因突变引起。心脏的临床重要性要求Dstrophin在心肌中的功能是开发有效的DMD治疗方法的中心焦点。肌营养不良蛋白将内部细胞骨架连接到膜上，起到机械缓冲的作用，保护膜免受收缩的影响。抗肌营养不良蛋白与膜的相互作用的稳定性对这一机械功能至关重要。重要的是，最近的研究表明，dystrophin相关蛋白dystrobrevin(DB)显著加强了dystrophin-膜在心肌和骨骼肌中的相互作用。这一新发现对截断的dystrophin结构的设计具有重要的意义，该结构旨在通过 基因治疗载体。Db与抗肌营养不良蛋白和膜结合的肌聚糖复合体结合，提示抗肌营养不良蛋白增强抗肌营养不良蛋白-膜相互作用的潜在机制。Db在维持dystrophin信号复合体方面也起着重要作用，主要是通过与信号转接器蛋白Syntroin的相互作用。Db在调节dystrophin的双重机械和信号功能中的重要作用，使我们充分理解Db的相互作用，这对于设计适合于基因治疗的Mu-dystrophin结构至关重要。DB在体内增强dystrophin功能的生理机制知之甚少。对dystrophin中枢功能调节因素的有限理解代表了生物医学知识中的一个重要缺口，抑制了设计完全功能的dystrophin结构的能力。长期目标是开发一种功能齐全的肌营养不良蛋白结构，为病毒介导的DMD基因治疗奠定基础。这项应用的总体目标是1)了解DB在稳定dystrophin信号复合体和加强dystrophin与膜的机械相互作用中的作用，以及2)将这一知识转化为u-dystrophin结构设计中与生理相关的改进。中心假说是，Db对形成完整的dystrophin信号复合体是必不可少的，并显著加强了dystrophin-膜相互作用，并且在Mu-dystrophin结构中包含Db结合结构域将导致Mu-Dystrophin心脏功能的显著改善。

DESCRIPTION (provided by applicant):Heart disease is a leading cause of death in patients with Duchenne muscular dystrophy (DMD). DMD is a uniformly fatal disease characterized by severe skeletal muscle injury and cardiomyopathy, resulting from mutations within the dystrophin gene. The clinical importance of the heart requires that dystrophin's function in the myocardium be a central focus in the development of effective therapies for DMD. Dystrophin connects the internal cytoskeleton to the membrane and functions as a mechanical buffer, protecting the membrane from the forces of contraction. The stability of dystrophin's interaction with the membrane is essential to this mechanical function. Importantly, recent studies have demonstrated that the dystrophin associated protein, dystrobrevin (DB) significantly strengthens the dystrophin-membrane interaction in both cardiac and skeletal muscle. This new finding has significant implications for the design of truncated dystrophin constructs intended for delivery by gene therapy vectors. DB binds to both dystrophin and the membrane bound sarcoglycan complex suggesting a potential mechanism for dystrobrevin's reinforcement of the dystrophin-membrane interaction. DB also plays an important role in maintaining the dystrophin signaling complex, primarily through interactions with the signaling adapter protein syntrophin. DB's important role in modulating the dual mechanical and signaling functions of dystrophin, make a full understanding of DB's interactions essential for the design of mu-dystrophin constructs suitable for genetic therapy. Little is known about the physiological mechanisms by which DB potentiates dystrophin's function in vivo. This limited understanding of factors regulating dystrophin's central functions represents an important gap in biomedical knowledge, inhibiting the ability to design fully functional mu- dystrophin constructs. The long-term goal is to develop a fully functional mu-dystrophin constructs that will form the basis of a viral mediated gene therapy for DMD. The overall objectives of this application are to 1) understand the role of DB in stabilizing the dystrophin signaling complex and reinforcing dystrophin's mechanical interaction with the membrane and 2) translate this knowledge into physiologically relevant improvements in the design of mu-dystrophin constructs. The central hypothesis is that DB is essential to forming the full dystrophin signaling complex and significantly strengthens the dystrophin-membrane interaction and that inclusion of a DB binding domain in mu-dystrophin constructs will result in significant improvements of mu-dystrophin functionality within the heart.