Targeted neuromodulation strategies to delay hypoglossal motoneuron death and preserve tongue strength, function, and structure in a mouse model of ALS

项目摘要 肌萎缩侧索硬化症(ALS)最令人衰弱的后果之一是吞咽障碍 (吞咽困难)，这与严重的发病率、抑郁/社会孤立和早期死亡有关。从… 从神经学的角度来看，ALS患者的吞咽困难被归因于由以下原因引起的进行性舌无力 舌下神经及其轴突(舌下神经)的变性 肌肉。进行性舌无力和萎缩最终导致几乎所有ALS患者无法进食和 自然饮用；取而代之的是，它们必须依靠喂养管生存。尽管有多起危及生命的 肌萎缩侧索硬化症吞咽困难的后果，目前的治疗方法，包括FDA批准的药物利鲁唑和 依达拉奉对吞咽功能无明显影响。因此，临床上迫切需要确定 针对吞咽困难潜在病理生理的有效治疗方案以保护吞咽 功能，并通过代理，显著延长生存时间和改善ALS患者的生活质量。 在这个项目中，为了满足这一临床需求，我们将利用ALS的翻译小鼠模型 吞咽困难探索光遗传刺激(opto-stim)作为一种针对舌头的治疗策略。这个 Optostim治疗是一种基于基因治疗的方法，已被证明可以促进神经元的存活 神经系统损伤中的生长、肌肉再生。在我们的方法中，我们将使用opto-stim来选择性地 “兴奋”舌下神经元引起小鼠必须克服的舌肌收缩/阻力 在自愿喝水的同时，充分伸出舌头。我们假设这个政权， 协同整合光遗传学和舌头训练的好处，有可能预防 或者延缓舌下变性和相关的舌体无力的进展。 为了探索光刺激治疗的效果，我们的项目分为两个目标。在目标1中，我们将应用 ALS小鼠在临床疾病时开始每周三次的高频和低频光刺激治疗 开始(即体重开始下降)，并评估治疗对舌运动和吞咽的影响 从疾病开始到末期(即20%体重)的功能(通过透视)和舔舔力(通过力舔舔计) 损失)。在目标2中，我们将使用各种组织学评估来量化相应的神经再生 舌下核神经元、舌下神经和舌肌的变化 建立临床病理相关性的神经调节策略。我们的结果将为我们提供对 基于光遗传的治疗策略在肌萎缩侧索硬化症中的疗效和机制。光遗传学一直是 获得越来越大的翻译潜力，可能对晚期ALS特别有利 不能参加替代治疗计划但仍有可能对治疗有反应的患者。

Project Summary One of the most debilitating consequences of amyotrophic lateral sclerosis (ALS) is swallowing impairment (dysphagia), which is associated with significant morbidity, depression/social isolation, and early mortality. From a neurological perspective, dysphagia in ALS has been attributed to progressive tongue weakness caused by degeneration of brainstem hypoglossal neurons and their axons (hypoglossal nerve) innervating the tongue muscles. Progressive tongue weakness and atrophy ultimately render nearly all ALS patients unable to eat and drink naturally; instead, they must depend on a feeding tube for survival. Despite the multiple life-threatening consequences of dysphagia in ALS, current therapies, including the FDA-approved drugs riluzole and edaravone, have no beneficial effect on swallowing function. Therefore, there is an urgent clinical need to identify effective therapeutic solutions targeting the underlying pathophysiology of dysphagia to preserve swallowing function, and by proxy, significantly extend survival and improve the quality of life for ALS patients. In this project, to address this clinical need, we will leverage a translational mouse model of ALS with dysphagia to explore optogenetic stimulation (opto-stim) as a therapeutic strategy targeting the tongue. The opto-stim treatment is a gene therapy-based approach that has been shown to promote neuronal survival, nerve growth, and muscle reinnervation in nervous system injury. In our approach, we will use opto-stim to selectively “excite” hypoglossal neurons to cause tongue muscle contraction/resistance that mice must overcome to sufficiently protrude the tongue while voluntarily drinking from a waterspout. We hypothesize that this regime, synergistically integrating the benefits of optogenetics and tongue exercise training, has the potential to prevent or slow down the progression of hypoglossal degeneration and associated tongue weakness. To explore the effects of opto-stim treatment, our project is divided into two aims. In Aim 1, we will apply high- and low-frequency opto-stim treatments three times per week in ALS mice, initiated at clinical disease onset (i.e., start of body weight decline), and assess the treatment effect on tongue motility and swallowing function (via fluoroscopy) and lick force (via force-lickometer) from disease onset to end-stage (i.e., 20% weight loss). In Aim 2, we will employ a variety of histological assessments to quantify the corresponding neuroplastic changes in the hypoglossal nucleus neurons, hypoglossal nerve, and the tongue muscles in response to each neuromodulation strategy to establish clinico-pathological correlations. Our results will provide insight into therapeutic effects and mechanisms of optogenetic-based treatment strategies in ALS. Optogenetics has been gaining increasingly significant translational potential and may be particularly beneficial for advanced-stage ALS patients who cannot participate in alternative treatment programs but may still respond to treatment.