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Chen Y, Zhang W, Lv H, Wang Z, Hao H, Yuan Y, Zheng Y. Pathological findings with vacuoles in anti-mitochondrial antibody-positive inflammatory myopathy. BMC Musculoskelet Disord 2024; 25:257. [PMID: 38566087 PMCID: PMC10985968 DOI: 10.1186/s12891-023-06941-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 10/06/2023] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND A few patients with inflammatory myopathy showed anti-mitochondrial antibody (AMA) positivity. This study aimed to report the clinical and pathological findings with vacuoles in 3 cases of such patients. METHODS Three cases with myositis from the Myositis Clinical Database of Peking University First Hospital were identified with AMA positivity. Their clinical records were retrospectively reviewed and the data was extracted. All the 3 cases underwent muscle biopsy. RESULTS Three middle-aged patients presented with chronic-onset weakness of proximal limbs, marked elevation of creatine kinase, and AMA-positivity. Two of the 3 cases meet the criteria of primary biliary cholangitis. All the 3 cases presented with cardiac involvement and proteinuria. Two cases developed type 2 respiratory failure. MRI of the thigh muscle showed multiple patches of edema bilaterally in both cases, mostly in the adductor magnus. Pathological findings include degeneration of muscle fibers, diffused MHC-I positivity, and complement deposits on cell membranes. Vacuoles without rims of different sizes were discovered under the membrane of the muscle fibers. A few RBFs were discovered in case 1, while a diffused proliferation of endomysium and perimysium was shown in case 2. CONCLUSIONS AMA-positive inflammatory myopathy is a disease that could affect multiple systems. Apart from inflammatory changes, the pathological findings of muscle can also present vacuoles.
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Affiliation(s)
- Yuanchong Chen
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, Xicheng District, Beijing, 100034, China
- Department of Radiology, Peking University First Hospital, No.8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Wei Zhang
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - He Lv
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Hongjun Hao
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Yiming Zheng
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, Xicheng District, Beijing, 100034, China.
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Chen BH, Zhu XM, Xie L, Hu HQ. Immune-mediated necrotizing myopathy: Report of two cases. World J Clin Cases 2023; 11:3552-3559. [PMID: 37383916 PMCID: PMC10294185 DOI: 10.12998/wjcc.v11.i15.3552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/25/2023] [Accepted: 04/24/2023] [Indexed: 05/25/2023] Open
Abstract
BACKGROUND Immune-mediated necrotizing myopathy is a rare autoimmune myopathy characterized by muscle weakness and elevated serum creatine kinase, with unique skeletal muscle pathology and magnetic resonance imaging features.
CASE SUMMARY In this paper, two patients are reported: One was positive for anti-signal recognition particle antibody, and the other was positive for anti-3-hydroxy-3-methylglutaryl coenzyme A reductase antibody.
CONCLUSION The clinical characteristics and treatment of the two patients were analysed, and the literature was reviewed to improve the recognition, diagnosis, and treatment of this disease.
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Affiliation(s)
- Bi-Hong Chen
- Department of Clinical Medicine, Weifang Medical University, Weifang 261053, Shandong Province, China
| | - Xue-Min Zhu
- School of Clinical Medicine, Weifang Medical University, Weifang 261053, Shandong Province, China
| | - Lei Xie
- School of Clinical Medicine, Weifang Medical University, Weifang 261053, Shandong Province, China
| | - Huai-Qiang Hu
- Department of Neurology, The 960th Hospital of People′s Liberation Army, Jinan 250031, Shandong Province, China
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Abstract
BACKGROUND Skeletal muscle development and regeneration depend on cellular fusion of myogenic progenitors to generate multinucleated myofibers. These progenitors utilize two muscle-specific fusogens, Myomaker and Myomerger, which function by remodeling cell membranes to fuse to each other or to existing myofibers. Myomaker and Myomerger expression is restricted to differentiating progenitor cells as they are not detected in adult myofibers. However, Myomaker remains expressed in myofibers from mice with muscular dystrophy. Ablation of Myomaker from dystrophic myofibers results in reduced membrane damage, leading to a model where persistent fusogen expression in myofibers, in contrast to myoblasts, is harmful. METHODS Dox-inducible transgenic mice were developed to ectopically express Myomaker or Myomerger in the myofiber compartment of skeletal muscle. We quantified indices of myofiber membrane damage, such as serum creatine kinase and IgM+ myofibers, and assessed general muscle histology, including central nucleation, myofiber size, and fibrosis. RESULTS Myomaker or Myomerger expression in myofibers independently caused membrane damage at acute time points. This damage led to muscle pathology, manifesting with centrally nucleated myofibers and muscle atrophy. Dual expression of both Myomaker and Myomerger in myofibers exacerbated several aspects of muscle pathology compared to expression of either fusogen by itself. CONCLUSIONS These data reveal that while myofibers can tolerate some level of Myomaker and Myomerger, expression of a single fusogen above a threshold or co-expression of both fusogens is damaging to myofibers. These results explain the paradigm that their expression in myofibers can have deleterious consequences in muscle pathologies and highlight the need for their highly restricted expression during myogenesis and fusion.
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Affiliation(s)
- Phillip C Witcher
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Chengyi Sun
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, 45229, USA.
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Thompson K, Stroud DA, Thorburn DR, Taylor RW. Investigation of oxidative phosphorylation activity and complex composition in mitochondrial disease. Handb Clin Neurol 2023; 194:127-139. [PMID: 36813309 DOI: 10.1016/b978-0-12-821751-1.00008-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
A multidisciplinary approach to the laboratory diagnosis of mitochondrial disease has long been applied, with crucial information provided by deep clinical phenotyping, blood investigations, and biomarker screening as well as histopathological and biochemical testing of biopsy material to support molecular genetic screening. In an era of second and third generation sequencing technologies, traditional diagnostic algorithms for mitochondrial disease have been replaced by gene agnostic, genomic strategies including whole-exome sequencing (WES) and whole-genome sequencing (WGS), increasingly supported by other 'omics technologies (Alston et al., 2021). Whether a primary testing strategy, or one used to validate and interpret candidate genetic variants, the availability of a range of tests aimed at determining mitochondrial function (i.e., the assessment of individual respiratory chain enzyme activities in a tissue biopsy or cellular respiration in a patient cell line) remains an important part of the diagnostic armory. In this chapter, we summarize several disciplines used in the laboratory investigation of suspected mitochondrial disease, including the histopathological and biochemical assessment of mitochondrial function, as well as protein-based techniques to assess the steady-state levels of oxidative phosphorylation (OXPHOS) subunits and assembly of OXPHOS complexes via traditional (immunoblotting) and cutting-edge (quantitative proteomic) approaches.
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Affiliation(s)
- Kyle Thompson
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David A Stroud
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC, Australia; Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - David R Thorburn
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia; Mitochondrial Laboratory, Victorian Clinical Genetic Services, Melbourne, VIC, Australia
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom; NHS Highly Specialised Services for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom.
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Wang N, Han X, Hao S, Han J, Zhou X, Sun S, Tang J, Lu Y, Wu H, Ma S, Song X, Ji G. The clinical, myopathological, and molecular characteristics of 26 Chinese patients with dysferlinopathy: a high proportion of misdiagnosis and novel variants. BMC Neurol 2022; 22:398. [PMID: 36319958 PMCID: PMC9623978 DOI: 10.1186/s12883-022-02905-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 09/20/2022] [Accepted: 09/27/2022] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Dysferlinopathy is an autosomal recessive muscular dystrophy caused by pathogenic variants in the dysferlin (DYSF) gene. This disease shows heterogeneous clinical phenotypes and genetic characteristics. METHODS We reviewed the clinical and pathological data as well as the molecular characteristics of 26 Chinese patients with dysferlinopathy screened by immunohistochemistry staining and pathogenic variants in DYSF genes. RESULTS Among 26 patients with dysferlinopathy, 18 patients (69.2%) presented as Limb-girdle Muscular Dystrophy Type R2 (LGMD R2), 4 (15.4%) had a phenotype of Miyoshi myopathy (MM), and 4 (15.4%) presented as asymptomatic hyperCKemia. Fifteen patients (57.7%) were originally misdiagnosed as inflammatory myopathy or other diseases. Fifteen novel variants were identified among the 40 variant sites identified in this cohort. CONCLUSION Dysferlinopathy is a clinically and genetically heterogeneous group of disorders with various phenotypes, a high proportion of novel variants, and a high rate of misdiagnosis before immunohistochemistry staining and genetic analysis.
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Affiliation(s)
- Ning Wang
- grid.452702.60000 0004 1804 3009Department of Neurology, The Second Hospital of Hebei Medical University, 050000 Shijiazhuang, Hebei People’s Republic of China ,grid.256883.20000 0004 1760 8442The Key Laboratory of Neurology (Hebei Medical University), Ministry of Education, 050000 Shijiazhuang, Hebei People’s Republic of China
| | - Xu Han
- grid.452702.60000 0004 1804 3009Department of Neurology, The Second Hospital of Hebei Medical University, 050000 Shijiazhuang, Hebei People’s Republic of China ,grid.256883.20000 0004 1760 8442The Key Laboratory of Neurology (Hebei Medical University), Ministry of Education, 050000 Shijiazhuang, Hebei People’s Republic of China
| | - Shengpu Hao
- grid.452702.60000 0004 1804 3009Department of Neurology, The Second Hospital of Hebei Medical University, 050000 Shijiazhuang, Hebei People’s Republic of China ,grid.256883.20000 0004 1760 8442The Key Laboratory of Neurology (Hebei Medical University), Ministry of Education, 050000 Shijiazhuang, Hebei People’s Republic of China
| | - Jingzhe Han
- grid.452702.60000 0004 1804 3009Department of Neurology, The Second Hospital of Hebei Medical University, 050000 Shijiazhuang, Hebei People’s Republic of China ,grid.256883.20000 0004 1760 8442The Key Laboratory of Neurology (Hebei Medical University), Ministry of Education, 050000 Shijiazhuang, Hebei People’s Republic of China
| | | | - Shuyan Sun
- grid.452702.60000 0004 1804 3009Department of Neurology, The Second Hospital of Hebei Medical University, 050000 Shijiazhuang, Hebei People’s Republic of China ,grid.256883.20000 0004 1760 8442The Key Laboratory of Neurology (Hebei Medical University), Ministry of Education, 050000 Shijiazhuang, Hebei People’s Republic of China
| | - Jin Tang
- grid.452702.60000 0004 1804 3009Department of Neurology, The Second Hospital of Hebei Medical University, 050000 Shijiazhuang, Hebei People’s Republic of China ,grid.256883.20000 0004 1760 8442The Key Laboratory of Neurology (Hebei Medical University), Ministry of Education, 050000 Shijiazhuang, Hebei People’s Republic of China
| | - Yanpeng Lu
- grid.452702.60000 0004 1804 3009Department of Neurology, The Second Hospital of Hebei Medical University, 050000 Shijiazhuang, Hebei People’s Republic of China ,grid.256883.20000 0004 1760 8442The Key Laboratory of Neurology (Hebei Medical University), Ministry of Education, 050000 Shijiazhuang, Hebei People’s Republic of China
| | - Hongran Wu
- grid.452702.60000 0004 1804 3009Department of Neurology, The Second Hospital of Hebei Medical University, 050000 Shijiazhuang, Hebei People’s Republic of China ,grid.256883.20000 0004 1760 8442The Key Laboratory of Neurology (Hebei Medical University), Ministry of Education, 050000 Shijiazhuang, Hebei People’s Republic of China
| | - Shaojuan Ma
- grid.452702.60000 0004 1804 3009Department of Neurology, The Second Hospital of Hebei Medical University, 050000 Shijiazhuang, Hebei People’s Republic of China ,grid.256883.20000 0004 1760 8442The Key Laboratory of Neurology (Hebei Medical University), Ministry of Education, 050000 Shijiazhuang, Hebei People’s Republic of China
| | - Xueqin Song
- grid.452702.60000 0004 1804 3009Department of Neurology, The Second Hospital of Hebei Medical University, 050000 Shijiazhuang, Hebei People’s Republic of China ,grid.256883.20000 0004 1760 8442The Key Laboratory of Neurology (Hebei Medical University), Ministry of Education, 050000 Shijiazhuang, Hebei People’s Republic of China
| | - Guang Ji
- grid.452702.60000 0004 1804 3009Department of Neurology, The Second Hospital of Hebei Medical University, 050000 Shijiazhuang, Hebei People’s Republic of China ,grid.256883.20000 0004 1760 8442The Key Laboratory of Neurology (Hebei Medical University), Ministry of Education, 050000 Shijiazhuang, Hebei People’s Republic of China
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Liu X, Zhang Y, Zhang S, Sun A, Zheng D, Fan D, Liu X. Different electrophysiology patterns in GNE myopathy. Orphanet J Rare Dis 2022; 17:206. [PMID: 35590323 PMCID: PMC9118620 DOI: 10.1186/s13023-022-02355-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 05/08/2022] [Indexed: 12/24/2022] Open
Abstract
Background GNE myopathy is a rare distal myopathy caused by mutations of the GNE gene. A few cases of GNE myopathy accompanied by neurogenic features of electrophysiology mimicking hereditary motor neuropathy were reported recently. We confirmed this feature and described the clinical phenotype and mutations of GNE myopathy in these rare cases. Results The absence of lower limb tendon reflexes, decreased compound muscle action potentials in lower leg motor nerves, and neurogenic pattern of electromyography suggested neuropathy in four patients. However, muscle pathology revealed a predominantly myogenic pattern. The follow-up electroneurography results implied that the compound motor action potential amplitudes deteriorated over time. Next-generation sequencing identified three novel variants of the GNE gene, c.2054T > C (p.Val685Ala), c.424G > A (p.Gly142Arg) and c.944T > C (p.Phe315Ser), as well as two hotspot mutations, c.115C > T(p.Arg39*) and c.620A > T(p.Asp207Val), in these patients. These novel mutations cosegregated with disease in the family. Conclusions These rare cases supported the existence of neurogenic features of electrophysiology different from the typical myopathic pattern of GNE myopathy. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-022-02355-0.
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Affiliation(s)
- Xiangyi Liu
- Department of Neurology, Peking University Third Hospital, No. 49, North Garden Road, Haidian District, Beijing, 100191, China
| | - Yingshuang Zhang
- Department of Neurology, Peking University Third Hospital, No. 49, North Garden Road, Haidian District, Beijing, 100191, China
| | - Shuo Zhang
- Department of Neurology, Peking University Third Hospital, No. 49, North Garden Road, Haidian District, Beijing, 100191, China
| | - Aping Sun
- Department of Neurology, Peking University Third Hospital, No. 49, North Garden Road, Haidian District, Beijing, 100191, China
| | - Danfeng Zheng
- Department of Neurology, Peking University Third Hospital, No. 49, North Garden Road, Haidian District, Beijing, 100191, China
| | - Dongsheng Fan
- Department of Neurology, Peking University Third Hospital, No. 49, North Garden Road, Haidian District, Beijing, 100191, China
| | - Xiaoxuan Liu
- Department of Neurology, Peking University Third Hospital, No. 49, North Garden Road, Haidian District, Beijing, 100191, China.
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Huang K, Li QX, Duan HQ, Luo YB, Bi FF, Yang H. Findings of limb-girdle muscular dystrophy R7 telethonin-related patients from a Chinese neuromuscular center. Neurogenetics 2022; 23:37-44. [PMID: 34982307 DOI: 10.1007/s10048-021-00681-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 12/23/2021] [Indexed: 12/29/2022]
Abstract
Limb-girdle muscular dystrophy (LGMD) is a group of clinically and genetically heterogeneous neuromuscular disorders. LGMD-R7, which is caused by telethonin gene (TCAP) mutations, is one of the rarest forms of LGMD, and only a small number of LGMD-R7 cases have been described and mostly include patients from Brazil. A total of two LGMD-R7 patients were enrolled at a Chinese neuromuscular center. Demographic and clinical data were collected. Laboratory investigations and electromyography were performed. Routine and immunohistochemistry staining of muscle specimens was performed, and a next-generation sequencing panel array for genes associated with hereditary neuromuscular disorders was used for analysis. The patients exhibited predominant muscle weakness. Electromyography revealed myopathic changes. The muscle biopsy showed myopathic features, such as increased fiber size variation, muscle fiber atrophy and regeneration, slight hyperplasia of the connective tissue, and disarray of the myofibrillar network. Two patients were confirmed to have mutations in the open reading frame of TCAP by next-generation sequencing. One patient had compound heterozygous mutations, and the other patient harbored a novel homozygous mutation. Western blotting analysis of the skeletal muscle lysate confirmed the absence of telethonin in the patients. We described two LGMD-R7 patients presenting a classical LGMD phenotype and a novel homozygous TCAP mutation. Our research expands the spectrum of LGMD-R7 due to TCAP mutations based on patients from a Chinese neuromuscular center.
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Abstract
PURPOSE OF REVIEW To review recent advances in immunopathology for idiopathic inflammatory myopathies, focusing on widely available immunohistochemical analyses. RECENT FINDINGS Sarcoplasmic expression of myxovirus resistance protein A (MxA) is specifically observed in all types of dermatomyositis and informs that type I interferons are crucially involved in its pathogenesis. It is a more sensitive diagnostic marker than perifascicular atrophy. Diffuse tiny dots in the sarcoplasm highlighted by p62 immunostaining are characteristically seen in immune-mediated necrotizing myopathy. This feature is linked to a chaperone-assisted selective autophagy pathway. Myofiber invasion by highly differentiated T cells, a marker of which is KLRG1, is specific to inclusion body myositis and has a crucial role in its pathogenesis. The recent advances in immunopathology contribute to increased diagnostic accuracy and a better understanding of the underlying pathophysiology in different types of idiopathic inflammatory myopathies.
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Affiliation(s)
- Akinori Uruha
- Department of Neuropathology, Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Berlin, Germany. .,Department of Neurology, Tokyo Metropolitan Neurological Hospital, 2-6-1 Musashidai, Fuchu, Tokyo, 183-0042, Japan.
| | - Hans-Hilmar Goebel
- Department of Neuropathology, Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Berlin, Germany.,Department of Neuropathology, Universitätsmedizin Mainz, Langenbeckstraße 1, 55131, Mainz, Germany
| | - Werner Stenzel
- Department of Neuropathology, Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Berlin, Germany.,Leibniz Science Campus Chronic Inflammation, Charitéplatz 1, 10117, Berlin, Germany
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Doyle JJ, Vrancx C, Maios C, Labarre A, Patten SA, Parker JA. Modulating the endoplasmic reticulum stress response attenuates neurodegeneration in a Caenorhabditis elegans model of spinal muscular atrophy. Dis Model Mech 2020; 13:dmm.041350. [PMID: 33106327 PMCID: PMC7774902 DOI: 10.1242/dmm.041350] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/28/2020] [Indexed: 11/20/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating autosomal recessive neuromuscular disease resulting in muscle atrophy and neurodegeneration, and is the leading genetic cause of infant death. SMA arises when there are homozygous deletion mutations in the human SMN1 gene, leading to a decrease in corresponding SMN1 protein. Although SMN1 is expressed across multiple tissue types, much of the previous research into SMA focused on the neuronal aspect of the disease, overlooking many of the potential non-neuronal aspects of the disease. Therefore, we sought to address this gap in knowledge by modeling SMA in the nematode Caenorhabditis elegans. We mutated a previously uncharacterized allele, which resulted in the onset of mild SMA-like phenotypes, allowing us to monitor the onset of phenotypes at different stages. We observed that these mutant animals recapitulated many key features of the human disease, and most importantly, we observed that muscle dysfunction preceded neurodegeneration. Furthermore, we tested the therapeutic efficacy of targeting endoplasmic reticulum (ER) stress in non-neuronal cells and found it to be more effective than targeting ER stress in neuronal cells. We also found that the most potent therapeutic potential came from a combination of ER- and neuromuscular junction-targeted drugs. Together, our results suggest an important non-neuronal component of SMA pathology and highlight new considerations for therapeutic intervention. Summary: A new non-larval-lethal C. elegans model of spinal muscular atrophy shows mild phenotypes, such as muscle cell and neuronal degeneration, and is therefore useful for testing potential drug treatments.
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Affiliation(s)
- James J Doyle
- Division of Experimental Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada.,Metabolic Disorders and Complications, Research Institute of the McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada
| | - Celine Vrancx
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal and Department of Neuroscience, University of Montreal, Montreal, Quebec H2X 0A9, Canada
| | - Claudia Maios
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal and Department of Neuroscience, University of Montreal, Montreal, Quebec H2X 0A9, Canada
| | - Audrey Labarre
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal and Department of Neuroscience, University of Montreal, Montreal, Quebec H2X 0A9, Canada
| | | | - J Alex Parker
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal and Department of Neuroscience, University of Montreal, Montreal, Quebec H2X 0A9, Canada
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Hamel J, Tawil R. Case Studies on the Genetic and Clinical Diagnosis of Facioscapulohumeral Muscular Dystrophy. Neurol Clin 2020; 38:529-540. [PMID: 32703466 DOI: 10.1016/j.ncl.2020.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Facioscapulohumeral muscular dystrophy is the second most common adult muscular dystrophy and is caused by DUX4 protein. DUX4 is expressed when the locus on chromosome 4q35 is hypomethylated. The clinical features can be nearly pathognomonic with facial weakness, scapular winging, and abdominal weakness with a positive Beevor sign. Diagnosis of late-onset or milder disease is often more challenging. Diseases mimicking the facioscapulohumeral muscular dystrophy phenotype should be recognized. We present 6 cases to illustrate both clinical and genetic diagnostic challenges in facioscapulohumeral muscular dystrophy and provide examples on how to navigate the different steps of genetic testing.
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Affiliation(s)
- Johanna Hamel
- Department of Neurology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 673, Rochester, NY 14642, USA.
| | - Rabi Tawil
- Department of Neurology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 673, Rochester, NY 14642, USA
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Lehka L, Rędowicz MJ. Mechanisms regulating myoblast fusion: A multilevel interplay. Semin Cell Dev Biol 2020; 104:81-92. [PMID: 32063453 DOI: 10.1016/j.semcdb.2020.02.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/07/2020] [Accepted: 02/08/2020] [Indexed: 02/07/2023]
Abstract
Myoblast fusion into myotubes is one of the crucial steps of skeletal muscle development (myogenesis). The fusion is preceded by specification of a myogenic lineage (mesodermal progenitors) differentiating into myoblasts and is followed by myofiber-type specification and neuromuscular junction formation. Similarly to other processes of myogenesis, the fusion requires a very precise spatial and temporal regulation occuring both during embryonic development as well as regeneration and repair of the muscle. A plethora of genes and their products is involved in regulation of myoblast fusion and a precise multilevel interplay between them is crucial for myogenic cells to fuse. In this review, we describe both cellular events taking place during myoblast fusion (migration, adhesion, elongation, cell-cell recognition, alignment, and fusion of myoblast membranes enabling formation of myotubes) as well as recent findings on mechanisms regulating this process. Also, we present muscle disorders in humans that have been associated with defects in genes involved in regulation of myoblast fusion.
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Abstract
CLINICAL/METHODICAL ISSUE Muscular injuries represent the most common musculoskeletal lesions. Especially in professional athletes an imaging clarification is essential in order to define the exact location of the lesion, the affected muscles, the extent and degree of the injury as well as to define possible concomitant complications. The best possible therapy can be initiated and a necessary rest period for a low risk resumption of sporting activity can be individually specified. STANDARD RADIOLOGICAL METHODS/METHODICAL INNOVATIONS Due to technical improvements, for example mobile devices and thus increased rapid availability as well as relative cost-effectiveness compared to other modalities, the imaging evaluation of muscle injury would nowadays be unthinkable without ultrasound. PERFORMANCE The article discusses general prerequisites for the performance of muscle ultrasound as well as a standardized examination algorithm of muscle injuries beginning with general and leading to special tips and tricks. ACHIEVEMENTS/PRACTICAL RECOMMENDATIONS Despite the known investigator dependence, ultrasound enables a reliable and unerring imaging clarification of muscle injuries. For this reason, ultrasound should be considered as the first-line diagnostic imaging modality when dealing with muscle trauma.
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Abstract
OBJECTIVES Neutral lipid storage disease with myopathy (NLSDM) is a rare metabolic myopathy occurring owing to mutations in the patatin like phospholipase domain containing 2 (PNPLA2) gene. Till date, less than 50 patients with PNPLA2 mutations have been reported. In this study, we describe the clinical, pathological, and genetic findings, and muscle magnetic resonance imaging (MRI) changes in four Chinese patients with NLSDM. PATIENTS AND METHODS Peripheral blood smears were stained using Wright's stain. Muscle biopsies, muscle MRI, and sequence analysis of PNPLA2 gene were performed. RESULTS All patients exhibited slowly progressive myopathy during adulthood. Cardiomyopathy, sensorineural hearing loss, hepatic adipose infiltration, and hypertriglyceridemia were observed in some patients. Jordan's anomaly was detected in the blood smears of all patients. Muscle biopsies revealed the presence of massive lipid droplets and rimmed vacuoles in two patients. MR images of the lower lumbar, pelvis, and lower extremities showed the involvement of posterior compartment muscles. The anterior compartment muscles were found to be less affected. Gene analysis for PNPLA2 revealed an identical homozygous mutation c.757 + 1G > T in all patients. CONCLUSION Patients with NLSDM display clinical heterogeneities despite sharing the same mutation (c.757 + 1G > T) of the PNPLA2 gene, may suggest a founder effect in the region.
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Affiliation(s)
- Jiaze Tan
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Haitao Yang
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Jingchuan Fan
- Department of Medical Laboratory Technology, Institute of Life Sciences of Chongqing Medical University, Chongqing 400016, China
| | - Yulan Fan
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Fei Xiao
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China.
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14
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Hedberg-Oldfors C, Darin N, Oldfors A. Muscle pathology in Vici syndrome-A case study with a novel mutation in EPG5 and a summary of the literature. Neuromuscul Disord 2017; 27:771-776. [PMID: 28624465 DOI: 10.1016/j.nmd.2017.05.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/29/2017] [Accepted: 05/03/2017] [Indexed: 11/25/2022]
Abstract
Vici syndrome is a disorder characterized by myopathy, cardiomyopathy, agenesis of the corpus callosum, immunodeficiency, cataracts, hypopigmentation, microcephaly, gross developmental delay and failure to thrive. It is caused by mutations in EPG5, which encodes a protein involved in the autophagy pathway. Although myopathy is part of the syndrome, few publications have described the muscle pathology. We present a detailed morphological analysis in a boy with Vici syndrome due to a novel homozygous one-base deletion in EPG5 (c.784delA), and we review the histopathological findings from previous reports. Muscle biopsy was performed at three months of age and demonstrated small vacuolated fibers, frequently with internal nuclei, and expressing developmental and fast myosin isoforms. There was an increase in acid phosphatase activity in the small fibers, which also showed LAMP-2 upregulation, glycogen accumulation and contained numerous p62-positive inclusions and some lipid droplets. Electron microscopy demonstrated hypoplastic fibers with massive glycogen accumulation and extensive disorganization of the myofibrils. This study expands the muscle pathological features of Vici syndrome and demonstrates a pattern of vacuolar myopathy with glycogen storage and immature, hypoplastic and atrophic muscle fibers. Increased lysosomes and accumulation of p62 are in line with a disturbance of the autophagic pathway as an essential part of the pathogenesis.
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Affiliation(s)
| | - Niklas Darin
- Department of Pediatrics, University of Gothenburg, The Queen Silvia Children's Hospital, Gothenburg, Sweden
| | - Anders Oldfors
- Department of Pathology and Genetics, University of Gothenburg, Gothenburg, Sweden
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15
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van der Ploeg A, Carlier PG, Carlier RY, Kissel JT, Schoser B, Wenninger S, Pestronk A, Barohn RJ, Dimachkie MM, Goker-Alpan O, Mozaffar T, Pena LDM, Simmons Z, Straub V, Guglieri M, Young P, Boentert M, Baudin PY, Wens S, Shafi R, Bjartmar C, Thurberg BL. Prospective exploratory muscle biopsy, imaging, and functional assessment in patients with late-onset Pompe disease treated with alglucosidase alfa: The EMBASSY Study. Mol Genet Metab 2016; 119:115-23. [PMID: 27473031 DOI: 10.1016/j.ymgme.2016.05.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 11/23/2022]
Abstract
BACKGROUND Late-onset Pompe disease is characterized by progressive skeletal myopathy followed by respiratory muscle weakness, typically leading to loss of ambulation and respiratory failure. In this population, enzyme replacement therapy (ERT) with alglucosidase alfa has been shown to stabilize respiratory function and improve mobility and muscle strength. Muscle pathology and glycogen clearance from skeletal muscle in treatment-naïve adults after ERT have not been extensively examined. METHODS This exploratory, open-label, multicenter study evaluated glycogen clearance in muscle tissue samples collected pre- and post- alglucosidase alfa treatment in treatment-naïve adults with late-onset Pompe disease. The primary endpoint was the quantitative reduction in percent tissue area occupied by glycogen in muscle biopsies from baseline to 6months. Secondary endpoints included qualitative histologic assessment of tissue glycogen distribution, secondary pathology changes, assessment of magnetic resonance images (MRIs) for intact muscle and fatty replacement, and functional assessments. RESULTS Sixteen patients completed the study. After 6months of ERT, the percent tissue area occupied by glycogen in quadriceps and deltoid muscles decreased in 10 and 8 patients, respectively. No changes were detected on MRI from baseline to 6months. A majority of patients showed improvements on functional assessments after 6months of treatment. All treatment-related adverse events were mild or moderate. CONCLUSIONS This exploratory study provides novel insights into the histopathologic effects of ERT in late-onset Pompe disease patients. Ultrastructural examination of muscle biopsies demonstrated reduced lysosomal glycogen after ERT. Findings are consistent with stabilization of disease by ERT in treatment-naïve patients with late-onset Pompe disease.
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Affiliation(s)
- Ans van der Ploeg
- Center for Lysosomal and Metabolic Diseases, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Pierre G Carlier
- Institut de Myologie, AIM and CEA NMR Laboratory - Spectroscopy Laboratory, Université Pierre et Marie Curie, Paris, France
| | - Robert-Yves Carlier
- Medical Imaging Department, Raymond Poincare University Hospital, Garches, France
| | - John T Kissel
- Department of Neurology, Division of Neuromuscular Medicine, Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Benedikt Schoser
- Friedrich-Baur-Institut, Neurologische Klinik, Klinikum der Universität München, München, Germany
| | - Stephan Wenninger
- Friedrich-Baur-Institut, Neurologische Klinik, Klinikum der Universität München, München, Germany
| | - Alan Pestronk
- Department of Neurology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Richard J Barohn
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Mazen M Dimachkie
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Ozlem Goker-Alpan
- Lysosomal Disorders Unit and Center for Clinical Trials, O&O Alpan LLC, Fairfax, VA, USA
| | - Tahseen Mozaffar
- Department of Neurology, University of California, Irvine, Irvine, CA, USA
| | - Loren D M Pena
- Division of Pediatric Medical Genetics, Duke University Medical Center, Durham, NC, USA
| | | | - Volker Straub
- Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Michela Guglieri
- Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Peter Young
- Department of Sleep Medicine and Neuromuscular Disorders, University Hospital of Münster, Münster, Germany
| | - Matthias Boentert
- Department of Sleep Medicine and Neuromuscular Disorders, University Hospital of Münster, Münster, Germany
| | | | - Stephan Wens
- Center for Lysosomal and Metabolic Diseases, Erasmus MC University Medical Center, Rotterdam, Netherlands
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16
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Abstract
Sporadic inclusion-body myositis (sIBM) presents in average at the sixth decade of life and affects three men for one woman. It is a non-lethal, slowly progressive but disabling disease. Except the striated muscles, no other organs (such as the interstitial lung) are involved. The phenotype of this myopathy is particular since it involves the axial muscles (camptocormia, swallowing dysfunction) and limb girdle (notably the quadriceps) but also the distal muscles (in particular the fingers' and wrists' flexors) in a bilateral but non-symmetrical manner. The clinical presentation is then very suggestive of the diagnosis, which remains to be proven by a muscle biopsy. Histological features defining the diagnosis associate endomysial inflammatory infiltrates with frequent invaded fibres (the myositis) and amyloid deposits generally accompanying rimmed vacuoles (the inclusions). There is still today a debate to know if this disease is at its beginning a degenerative or an auto-immune condition. Nonetheless, usual immunosuppressive drugs (corticosteroids, azathioprine, methotrexate) or polyvalent immunoglobulines remain ineffective and even may worsen the handicap. Some controlled randomized trials will soon be launched for this condition, but for now, the best therapeutic approach to slow down the rapidity of progression of the disease is to maintain muscle exercise with the help of the physiotherapists.
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Affiliation(s)
- O Benveniste
- Service de médecine interne 1, centre de référence des pathologies neuromusculaires Paris-Est, DHU i2B, faculté de médecine Pierre-et-Marie-Curie, hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, 47-83, boulevard de l'Hôpital, 75651 Paris cedex 13, France.
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