Gao Tianchu, Huo Jia, Xin Cheng, Yang Jing, Liu Qi, Dong Hui, Li Rui, Liu Yaling
Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
The Key Laboratory of Neurology, Hebei Medical University, Ministry of Education, Shijiazhuang, Hebei, China.
Front Aging Neurosci. 2023 Mar 14;15:1092607. doi: 10.3389/fnagi.2023.1092607. eCollection 2023.
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that widely affects motor neurons of the CNS. About 20% of patients with ALS have familial ALS (fALS). One of the classic models of ALS are SOD1 mice. Misfolded SOD1 protein can be overexpressed in motor neurons, which results in progressive paralysis of the limbs of mice. There is still no effective treatment for ALS. In recent years, the treatment of ALS by regulating autophagy has become a research hotspot. Autophagy obstacles have been confirmed to be one of the early pathological events of ALS. Rab7 is a member of the Ras superfamily and plays a key role in the late stage of autophagy. In our previous studies, we found that prenoylation of Rab7 was inhibited in the ALS model. Prenylation is a post-translational modification in which farnesyl or geranylgeranyl groups are covalently linked to target proteins. Based on these findings, we proposed the novel idea that the regulation of RabGGTB (the β-subunit of RabGGTase) mediated prenylation modification of Rab7, and that this can be used as a prevention and treatment of ALS associated with abnormal protein accumulation.
In the present study, RabGGTB was overexpressed in mouse spinal cord motoneurons by using adeno-associated virus as vector. Then immunofluorescence quantitative analysis was used for pathological study. The body weight, footprint analysis, the accelerating rotarod test, and neurological deficits score were used to evaluate animal behavior.
Our results show that the protein level of RabGGTB was significantly increased in the lumbar and thoracic regions of spinal cord motoneurons of injected mice. Furthermore, the onset time and survival time of SOD1 mice injected with AAV9-RabGGTB-GFP were delayed compared with those of mice without overexpression. At the same time, we also observed a decrease in SOD1 misfolded and glial overactivation in the lumbar spinal cord of these SOD1 mice.
The findings reported here show that RabGGTB plays a significant role in the pathogenesis of SOD1 mice and with great therapeutic potential for reducing abnormal aggregation of SOD1 in ALS.
肌萎缩侧索硬化症（ALS）是一种神经退行性疾病，广泛影响中枢神经系统的运动神经元。约20%的ALS患者患有家族性ALS（fALS）。ALS的经典模型之一是SOD1小鼠。错误折叠的SOD1蛋白可在运动神经元中过度表达，导致小鼠肢体进行性麻痹。目前尚无有效的ALS治疗方法。近年来，通过调节自噬治疗ALS已成为研究热点。自噬障碍已被证实是ALS早期病理事件之一。Rab7是Ras超家族的成员，在自噬后期起关键作用。在我们之前的研究中，我们发现Rab7的异戊二烯化在ALS模型中受到抑制。异戊二烯化是一种翻译后修饰，其中法尼基或香叶基香叶基基团与靶蛋白共价连接。基于这些发现，我们提出了一个新的观点，即调节RabGGTB（RabGGTase的β亚基）介导的Rab7异戊二烯化修饰，可用于预防和治疗与异常蛋白积累相关的ALS。
在本研究中，以腺相关病毒为载体，在小鼠脊髓运动神经元中过表达RabGGTB。然后采用免疫荧光定量分析进行病理研究。通过体重、足迹分析、加速转棒试验和神经功能缺损评分来评估动物行为。
我们的结果表明，注射小鼠脊髓运动神经元的腰段和胸段中RabGGTB的蛋白水平显著升高。此外，与未过表达的小鼠相比，注射AAV9-RabGGTB-GFP的SOD1小鼠的发病时间和存活时间延迟。同时我们还观察到这些SOD1小鼠腰段脊髓中SOD1错误折叠减少和胶质细胞过度激活减少。
本研究结果表明，RabGGTB在SOD1小鼠的发病机制中起重要作用，在减少ALS中SOD1异常聚集方面具有巨大的治疗潜力。
