背景:肌萎缩侧索硬化症(ALS)的特征是进行性运动神经元(MN)变性,导致神经肌肉接头(NMJ)拆除和严重的肌肉萎缩。核受体相互作用蛋白(NRIP)作为多功能蛋白发挥作用。它直接与钙调蛋白或α-肌动蛋白2相互作用,充当肌肉收缩和维持肌节完整性的钙传感器。此外,NRIP与乙酰胆碱受体(AChR)结合以稳定NMJ。肌肉中NRIP的丢失导致进行性运动神经元变性,NMJ结构异常,类似ALS表型。因此,我们假设NRIP可能是ALS的治疗因素.
方法:我们使用SOD1G93A小鼠,表达具有ALS连锁G93A突变的人SOD1,作为ALS模型。产生编码人NRIP基因(AAV-NRIP)的腺相关病毒载体,并将其注射到60日龄的SOD1G93A小鼠的肌肉中,在疾病发作之前。测量病理和行为变化以评估AAV-NRIP对SOD1G93A小鼠的疾病进展的治疗效果。
结果:SOD1G93A小鼠在脊髓和骨骼肌组织中的NRIP表达均低于野生型小鼠。在骨骼肌中观察到通过AAV-NRIP肌内注射的强制NRIP表达并逆行转导到脊髓中。AAV-NRIP基因治疗提高了SOD1G93A小鼠的运动距离和饲养频率。此外,AAV-NRIP增加肌纤维大小和肌球蛋白表达缓慢,改善NMJ变性和轴突终末神经支配,并增加SOD1G93A小鼠的α运动神经元(α-MNs)和复合肌肉动作电位(CMAP)的数量。
结论:AAV-NRIP基因治疗可改善肌肉萎缩,运动神经元变性,NMJ的轴突末端神经支配,导致SOD1G93A小鼠NMJ传递增加和运动功能改善。总的来说,AAV-NRIP可能是ALS的潜在治疗药物。
BACKGROUND: Amyotrophic lateral sclerosis (ALS) is characterized by progressive motor neuron (MN) degeneration, leading to neuromuscular junction (NMJ) dismantling and severe muscle atrophy. The nuclear receptor interaction protein (NRIP) functions as a multifunctional protein. It directly interacts with calmodulin or α-actinin 2, serving as a calcium sensor for muscle contraction and maintaining sarcomere integrity. Additionally, NRIP binds with the acetylcholine receptor (AChR) for NMJ stabilization. Loss of NRIP in muscles results in progressive motor neuron degeneration with abnormal NMJ architecture, resembling ALS phenotypes. Therefore, we hypothesize that NRIP could be a therapeutic factor for ALS.
METHODS: We used SOD1 G93A mice, expressing human SOD1 with the ALS-linked G93A mutation, as an ALS model. An adeno-associated virus vector encoding the human NRIP gene (AAV-NRIP) was generated and injected into the muscles of SOD1 G93A mice at 60 days of age, before disease onset. Pathological and behavioral changes were measured to evaluate the therapeutic effects of AAV-NRIP on the disease progression of SOD1 G93A mice.
RESULTS: SOD1 G93A mice exhibited lower NRIP expression than wild-type mice in both the spinal cord and skeletal muscle tissues. Forced NRIP expression through AAV-NRIP intramuscular injection was observed in skeletal muscles and retrogradely transduced into the spinal cord. AAV-NRIP gene therapy enhanced movement distance and rearing frequencies in SOD1 G93A mice. Moreover, AAV-NRIP increased myofiber size and slow myosin expression, ameliorated NMJ degeneration and axon terminal denervation at NMJ, and increased the number of α-motor neurons (α-MNs) and compound muscle action potential (CMAP) in SOD1 G93A mice.
CONCLUSIONS: AAV-NRIP gene therapy ameliorates muscle atrophy, motor neuron degeneration, and axon terminal denervation at NMJ, leading to increased NMJ transmission and improved motor functions in SOD1 G93A mice. Collectively, AAV-NRIP could be a potential therapeutic drug for ALS.