Therapeutic targeting of Nox2 and Nox4 in Duchenne Muscular Dystrophy

摘要： 杜氏肌营养不良症（DMD）是由一种基因突变引起的， 肌营养不良蛋白是肌肉正常工作所需的蛋白质。DMD患者表现出进行性肌无力 发生在骨骼肌和心肌中。心脏纤维化最终是他们过早死亡的主要原因。 死亡DMD无法治愈，因此它仍然是一个未满足的医疗需求。任何能改善 症状、生活质量或生存率对DMD患者有广泛而有意义的影响。许多 研究表明，营养不良的肌肉表现出高水平的氧化应激， NADPH氧化酶（Nox's）增加，这是ROS产生的主要细胞来源。Nox 2是主要的 Nox 4是骨骼肌中ROS的主要来源，而Nox 4已被鉴定为骨骼肌中ROS的主要来源。 心肌细胞和心肌成纤维细胞。最近的研究表明，Nox 2在骨骼肌中 功能障碍和心肌纤维化中的Nox 4。然而，尽管有强有力的证据表明Nox 2和4与DMD有关， 发病机制，该领域进展的关键障碍是选择性Nox 2或Nox 4抑制剂尚未被发现。 available.这个STTR第一阶段的应用是生物技术创业公司Fibronox LLC， 和两个学术实体，匹兹堡大学（UP）和亚利桑那大学（UA）。Hecker博士（Dr. Hecker） 是Fibronox的创始人兼首席科学官，也是第一个为氧化剂定义新角色的人- 产生酶，Nox 4，介导组织纤维化。赫克博士最近发现了第一个选择性的Nox 4 抑制剂先导候选药物，其中Fibronox已获得独家许可权。Pagano博士（UP） 确定了第一个选择性Nox 2抑制剂先导候选药物。使用这些创新的选择性Nox 2和Nox 4 抑制剂，它现在是可行的，第一次，以目标的氧化剂产生的DMD的主要来源。博士 Colson（UA）通过提供骨骼和心肌力学方面的专业知识来完善这个团队。整体 该项目的目的是证明在DMD小鼠中Nox 2的药理学靶向是概念验证。 足以减少ROS介导的炎症并改善骨骼肌功能，而药理学 靶向Nox 4将减少ROS介导的心脏纤维化，从而改善心脏功能， 生存目的1研究将确定Nox 4抑制剂对心脏纤维化的治疗效果，性能， 和DMD小鼠的存活率。目的2研究将确定Nox 2抑制剂对炎症的治疗效果。 反应和恢复骨骼肌功能的能力。STTR的长期目标 是为了解决DMD新型疗法的未满足需求。我们的目标是为 开发这些一流的选择性Nox抑制剂用于DMD适应症。这些新的治疗 策略解决DMD的关键病理特征：抑制Nox 2以恢复骨骼肌功能， 抑制Nox 4以减少纤维化并恢复心脏功能。这种双管齐下的方法提供了独立的 改善DMD患者生活质量和生存率的机会。

ABSTRACT: Duchenne muscular dystrophy (DMD) caused by a genetic mutation that prevents the production of dystrophin, a protein that muscles need to work properly. DMD patients exhibit progressive muscle weakness occurs in both skeletal and cardiac muscle. Cardiac fibrosis is ultimately the leading cause of their premature death. There is no cure for DMD, thus it remains an unmet medical need. Any therapeutic strategy that improves symptoms, quality of life, or survival would have a broad and meaningful impact for DMD patients. Numerous studies have demonstrated that dystrophic muscle exhibits high levels of oxidative stress, which is associated with increased NADPH-oxidases (Nox's) – a major cellular sources of ROS generation. Nox2 is the primary source of ROS in skeletal muscle, whereas Nox4 has been identified as the primary source of ROS in cardiomyocytes and cardiac myofibroblasts. Recent studies patients have implicated Nox2 in skeletal muscle dysfunction, and Nox4 in cardiac fibrosis. However, despite strong evidence implicating Nox2 and 4 in DMD pathogenesis, a critical barrier to progress in this area is that selective Nox2 or Nox4 inhibitors have not been available. This STTR Phase I application is a collaboration between biotech startup company, Fibronox LLC, and two academic entities, University of Pittsburgh (UP) and University of Arizona (UA). The PI (Dr. Hecker) is the Founder and Chief Scientific Officer of Fibronox, and was the first to define a novel role for the oxidant- generating enzyme, Nox4, in mediating tissue fibrosis. Dr. Hecker recently identified the first selective Nox4 inhibitor lead drug candidate, where Fibronox has obtained exclusive licensing rights. Dr. Pagano (UP) has identified the first selective Nox2 inhibitor lead drug candidate. Using these innovative selective Nox2 and Nox4 inhibitors, it is now feasible, for the first time, to target the primary source of oxidant generation in DMD. Dr. Colson (UA) rounds out this team by providing expertise in skeletal and cardiac muscle mechanics. The overall goal of this project is to demonstrate proof-of-concept that pharmacologic targeting of Nox2 in DMD mice is sufficient to reduce ROS-mediated inflammation and improve skeletal muscle function, whereas pharmacologic targeting of Nox4 will reduce ROS-mediated cardiac fibrosis, leading to improved cardiac function and increased survival. Aim 1 studies will determine the therapeutic efficacy of Nox4 inhibitors on cardiac fibrosis, performance, and survival in DMD mice. Aim 2 studies will determine the therapeutic efficacy of Nox2 inhibitors on inflammatory responses and the ability to restore skeletal muscle function in a DMD mouse model. The long-term STTR goal is to address the unmet need for novel therapies for DMD. Our objective is to provide proof-of-concept for the development of these first-in-class selective Nox inhibitors for a DMD indication. These novel therapeutic strategies address the key pathological features of DMD: Nox2 inhibition to restore skeletal muscle function and Nox4 inhibition to reduce fibrosis and restore cardiac function. This two-pronged approach offers independent opportunities to improve DMD patient quality of life and survival.