The Role of Epigenetics in Mitochondrial Biogenesis-Mediated Recovery after Spinal Cord Injury

该项目的目标是确定线粒体基因的表观遗传修饰在 脊髓损伤(SCI)后平台期的诱导，并利用这些修改来 促进经济复苏。脊髓损伤是一种破坏性的疾病，通常会导致损伤部位以下的功能丧失。在最近 多年来，服役人员一直受到更先进的战争的威胁，如简易爆炸 设备，最终导致更严重和复杂的伤害，包括脊髓损伤。毁灭性的和衰弱的 这些伤害的性质并没有减轻。退伍军人事务部(VA)是最大的医疗保健机构 为患有脊髓损伤的个人提供网络，为美国25%的受害者提供护理。改进 治疗脊髓损伤的疗法不仅对患者，而且对退伍军人管理局的医疗系统都有很大的好处。 脊髓损伤的定义是直接损伤脊髓，破坏血管系统，导致氧气减少。 在该区域内传递，并降低线粒体维持细胞能量的能力。到目前为止， 大多数针对脊髓损伤后线粒体功能障碍的研究都集中在下游方面。 线粒体功能(如抗氧化剂防御)。线粒体功能的重建 药物诱导线粒体生物发生(MB)仍然是一个未被探索但却是一个新的策略。 我之前曾报道，用美国食品和药物管理局批准的线粒体生物源性β2-肾上腺素能受体治疗 福莫特罗在脊髓损伤后8h开始使用，可改善脊髓线粒体功能，减少损伤 并在伤后7天(DPI)提高运动恢复能力。与其他已发布的数据一致， 福莫特罗的大部分改善发生在最初的2周内，之后恢复 停滞不前。在人类身上也观察到了类似的效果，大部分恢复发生在第一年内。 然后到达了一个平台期。然而，这一高原阶段发展背后的机制并不完全 明白了。通过确定其形成机制，可以防止和/或 逆转，有可能在受伤后继续恢复。我的初步研究揭示了基因 福莫特罗治疗的小鼠在恢复期(7DPI)和恢复期(DPI)损伤脊髓内的差异 平台期(15DPI)，即与线粒体功能相关的基因减少，并 与表观遗传修饰相关的基因增加。因此，我假设表观遗传学 改变导致脊髓内线粒体基因转录减少 平台期，阻止线粒体功能的持续恢复并限制其疗效 福莫特罗对小鼠的治疗。为了解决这一假设，我提出了以下具体目标：1)进一步 阐明脊髓损伤后恢复期(7DPI)和平台期脊髓内的遗传特征 (≥15DPI)，加和不加福莫特罗治疗；2)阐明表观遗传学机制 线粒体基因从恢复期过渡到平台期的转录修饰 脊髓损伤后，加和不加福莫特罗治疗；3)评估抑制表观遗传学的药理学效果 使用和不使用福莫特罗治疗的活体脊髓损伤后MB和恢复的事件。 成功完成这项提议可以为观察到的复苏平台期提供完整的信息 在SCI之后。我正在使用FDA批准的一种化合物，雄性和雌性小鼠，并在8小时后开始治疗 损伤，强调临床适用性。这项提案还将直接评估 我的发现是通过确定表观遗传状态的调节是否能改善受伤后的恢复。 我的指导团队已经制定了一个全面的职业发展计划，其中包括接触到 教育环境，提高口头和书面沟通能力的机会和指导 项目和实验室维护，以方便向独立过渡。这个项目和培训将促进 完成了我长期的职业目标，成为一名独立的退伍军人管理局研究员.

The goal of this project is to determine the role of epigenetic modifications of mitochondrial genes in the induction of the plateau phase after spinal cord injury (SCI), and to exploit these modifications to promote recovery. SCI is a devastating disorder often resulting in loss of function below the injury site. In recent years, service members have been threatened by more advanced warfare, such as improvised explosive devices, ultimately inducing more severe and complex injuries, including SCI. The devastating and debilitating nature of these injuries has not been lessened. The Department of Veterans Affairs (VA) is the largest healthcare network for individuals suffering from SCI, providing care for 25% of total victims in the United States. Improved therapeutics for the treatment of SCI would greatly benefit not only sufferers, but also the VA healthcare system. SCI is defined by direct trauma to the spinal cord, which disrupts the vasculature, leading to decreased oxygen delivery within the area and reducing the ability of mitochondria to maintain cellular energetics. Thus far, the majority of studies targeting mitochondrial dysfunction following SCI have focused on downstream aspects of mitochondrial function (e.g. antioxidant defenses). Reestablishment of mitochondrial function through pharmacological induction of mitochondrial biogenesis (MB) remains an underexplored but novel strategy. I previously reported that treatment with the mitochondrially biogenic FDA-approved β2-adrenergic receptor agonist formoterol beginning up to 8h after SCI improves spinal cord mitochondrial function, decreases lesion volume and enhances locomotor recovery by 7 days post-injury (DPI). Consistent with other published data, the majority of the improvements observed with formoterol occurred within the first 2 weeks, after which recovery plateaued. A similar effect is observed in humans, with the majority of recovery taking place within the first year then reaching a plateau. The mechanism behind the development of this plateau phase, however, is not fully understood. By determining the mechanism of its formation, the plateau phase could be prevented and/or reversed, potentially allowing for continued recovery following injury. My preliminary studies revealed genetic differences within the injured spinal cord of formoterol-treated mice between the recovery phase (7 DPI) and the plateau phase (15 DPI), namely a decrease in genes associated with mitochondrial function, and a concurrent increase in genes associated with epigenetic modifications. Therefore, I hypothesize that epigenetic alterations contribute to decreased transcription of mitochondrial genes within the spinal cord during the plateau phase, preventing continued recovery of mitochondrial function and limiting the efficacy of formoterol treatment in mice. To address this hypothesis, I propose the following Specific Aims: 1) Further elucidate the genetic profile within the spinal cord during the post-SCI recovery period (7 DPI) and plateau phase (≥15 DPI), with and without formoterol treatment in mice; 2) Elucidate the mechanisms of epigenetic modifications on the transcription of mitochondrial genes during the transition from recovery to plateau phase post-SCI, with and without formoterol treatment; 3) Assess the pharmacological efficacy of inhibiting epigenetic events on MB and recovery post-SCI in vivo, with and without formoterol treatment. Successful completion of this proposal could provide integral information into the recovery plateau observed after SCI. I am using an FDA-approved compound, male and female mice and initiating treatment up to 8h after injury, emphasizing the clinical applicability. This proposal will also directly assess the therapeutic potential of my findings by determining if modulation of epigenetic status improves recovery after injury. My mentoring team has formulated a comprehensive career development plan that includes exposure to a rich educational environment, opportunities to improve oral and written communication skills and mentoring on project and laboratory maintenance to ease transition to independence. This project and training will facilitate the completion of my long-term career goal of becoming and independent VA researcher.