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Li H, Yuan L, Yang H, Guo Y, Zheng W, Fan K, Deng S, Gong L, Xu H, Yang Z, Cheng J, Kang M, Deng H. Analysis of SOD1 Variants in Chinese Patients with Familial Amyotrophic Lateral Sclerosis. QJM 2023; 116:365-374. [PMID: 36661322 DOI: 10.1093/qjmed/hcad010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 12/27/2022] [Accepted: 01/10/2023] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease, and genetic contributors exert a significant role in the complicated pathogenesis. Identification of the genetic causes in ALS families could be valuable for early diagnosis and management. The development of potential drugs for patients with genetic defects will shed new light on ALS therapy. AIM To identify causative variants in three Chinese families with familial ALS (FALS), reveal the pathogenic mechanism, and look for the targeted drug for ALS. DESIGN AND METHODS Whole-exome sequencing and bioinformatics were used to perform genetic analysis of the ALS families. Functional analysis was performed to study the variants' function and search for potential drug targets. RESULTS Three heterozygous missense variants of the SOD1 gene were identified in families with FALS. The clinical manifestations of these patients include spinal onset, predominant lower motor neurons presentation, and absence of cognitive involvement. Functional analysis showed that all three SOD1 variants led to increased reactive oxygen species (ROS) levels, reduced cell viability, and formation of cytoplasmic aggregates. Remarkably, the decreased cell viability induced by variants was rescued after treatment with the ROS inhibitor N-acetylcysteine. CONCLUSIONS This study identified three SOD1 variants in three families with FALS. The variant SOD1 toxicity was associated with oxidative damage and aggregation, and N-acetylcysteine could rescue the decreased cell viability induced by these variants. Our findings support a pathogenic role for ROS in SOD1 deficiencies, and provide a potential drug N-acetylcysteine for ALS therapy, especially in SOD1-patients with limb onset.
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Affiliation(s)
- H Li
- Health Management Center, the Third Xiangya Hospital, Central South University, Changsha, China
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China
| | - L Yuan
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China
- Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha, China
- Disease Genome Research Center, Central South University, Changsha, China
| | - H Yang
- Department of Neurology, the Second Affiliated Hospital of Guizhou Medical University, Kaili, China
| | - Y Guo
- Department of Medical Information, School of Life Sciences, Central South University, Changsha, China
| | - W Zheng
- Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha, China
| | - K Fan
- Department of Neurology, Guizhou Provincial People's Hospital, Guiyang, China
| | - S Deng
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, China
| | - L Gong
- Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha, China
| | - H Xu
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China
| | - Z Yang
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China
| | - J Cheng
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China
| | - M Kang
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China
| | - H Deng
- Health Management Center, the Third Xiangya Hospital, Central South University, Changsha, China
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China
- Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha, China
- Disease Genome Research Center, Central South University, Changsha, China
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SOD1 in ALS: Taking Stock in Pathogenic Mechanisms and the Role of Glial and Muscle Cells. Antioxidants (Basel) 2022; 11:antiox11040614. [PMID: 35453299 PMCID: PMC9032988 DOI: 10.3390/antiox11040614] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/18/2022] [Accepted: 03/19/2022] [Indexed: 12/04/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the loss of motor neurons in the brain and spinal cord. While the exact causes of ALS are still unclear, the discovery that familial cases of ALS are related to mutations in the Cu/Zn superoxide dismutase (SOD1), a key antioxidant enzyme protecting cells from the deleterious effects of superoxide radicals, suggested that alterations in SOD1 functionality and/or aberrant SOD1 aggregation strongly contribute to ALS pathogenesis. A new scenario was opened in which, thanks to the generation of SOD1 related models, different mechanisms crucial for ALS progression were identified. These include excitotoxicity, oxidative stress, mitochondrial dysfunctions, and non-cell autonomous toxicity, also implicating altered Ca2+ metabolism. While most of the literature considers motor neurons as primary target of SOD1-mediated effects, here we mainly discuss the effects of SOD1 mutations in non-neuronal cells, such as glial and skeletal muscle cells, in ALS. Attention is given to the altered redox balance and Ca2+ homeostasis, two processes that are strictly related with each other. We also provide original data obtained in primary myocytes derived from hSOD1(G93A) transgenic mice, showing perturbed expression of Ca2+ transporters that may be responsible for altered mitochondrial Ca2+ fluxes. ALS-related SOD1 mutants are also responsible for early alterations of fundamental biological processes in skeletal myocytes that may impinge on skeletal muscle functions and the cross-talk between muscle cells and motor neurons during disease progression.
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