Therapeutic targeting of Nox2 and Nox4 in Duchenne Muscular Dystrophy

摘要： 杜氏肌营养不良症 (DMD) 由阻止产生 肌营养不良蛋白，肌肉正常工作所需的一种蛋白质。 DMD 患者表现出进行性肌肉无力 发生在骨骼肌和心肌中。心脏纤维化最终是导致其早产的主要原因 死亡。 DMD 无法治愈，因此它仍然是一个未得到满足的医疗需求。任何改善的治疗策略 症状、生活质量或生存将对 DMD 患者产生广泛且有意义的影响。众多 研究表明，营养不良的肌肉表现出高水平的氧化应激，这与 NADPH 氧化酶 (Nox) 增加，NADPH 氧化酶是 ROS 生成的主要细胞来源。 Nox2是主要的 骨骼肌中 ROS 的来源，而 Nox4 已被确定为骨骼肌中 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，Nox2 与患者骨骼肌有关 功能障碍和Nox4在心脏纤维化中的作用。然而，尽管有强有力的证据表明 Nox2 和 4 与 DMD 有关 发病机制中，该领域进展的一个关键障碍是选择性 Nox2 或 Nox4 抑制剂尚未被开发出来。 可用。 STTR 第一阶段应用是生物技术初创公司 Fibronox LLC 与 以及两个学术实体：匹兹堡大学 (UP) 和亚利桑那大学 (UA)。 PI（Hecker 博士） 是 Fibronox 的创始人兼首席科学官，也是第一个定义氧化剂新作用的人 产生酶Nox4，介导组织纤维化。 Hecker 博士最近发现了第一个选择性 Nox4 抑制剂先导候选药物，Fibronox 已获得该药物的独家许可权。帕加诺博士（UP）有 确定了第一个选择性 Nox2 抑制剂先导候选药物。使用这些创新的选择性 Nox2 和 Nox4 抑制剂，现在首次可以针对 DMD 中氧化剂生成的主要来源。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 该项目的目标是证明概念验证，即 DMD 小鼠中 Nox2 的药理靶向是 足以减少 ROS 介导的炎症并改善骨骼肌功能，而药理学 以 Nox4 为靶点将减少 ROS 介导的心脏纤维化，从而改善心脏功能并增加心脏功能。 生存。目标 1 研究将确定 Nox4 抑制剂对心脏纤维化、性能、 和 DMD 小鼠的存活率。目标 2 研究将确定 Nox2 抑制剂对炎症的治疗效果 DMD 小鼠模型中的反应和恢复骨骼肌功能的能力。 STTR 长期目标 旨在解决 DMD 新疗法未得到满足的需求。我们的目标是提供概念验证 开发这些一流的选择性 Nox 抑制剂用于 DMD 适应症。这些新颖的治疗 策略解决 DMD 的关键病理特征：抑制 Nox2 以恢复骨骼肌功能和 抑制Nox4可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.