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Du H, Chen Y, Zeng L, Wu R, Wu T, Zhu J. Myofibrillar myopathies due to a novel mutation in exon 8 of the LDB3 gene. Int J Rheum Dis 2024; 27:e15036. [PMID: 38333999 DOI: 10.1111/1756-185x.15036] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 12/23/2023] [Accepted: 12/30/2023] [Indexed: 02/10/2024]
Abstract
Myofibrillar myopathies (MFMs) are a group of genetically heterogeneous diseases affecting the skeletal and cardiac muscles. Myofibrillar myopathies are characterized by focal lysis of myogenic fibers and integration of degraded myogenic fiber products into inclusion bodies, which are typically rich in desmin and many other proteins. Herein, we report a case of a 54-year-old woman who experienced bilateral thigh weakness for over three years. She was diagnosed with MFMs based on muscle biopsy findings and the presence of a novel mutation in exon 8 of the LDB3 gene. Myofibrillar myopathies caused by a mutation in the LDB3 gene are extremely uncommon and often lack distinct clinical characteristics and typically exhibit a slow disease progression. When considering a diagnosis of MFMs, particularly in complex instances of autosomal dominant myopathies where muscle biopsies do not clearly indicate MFMs, it becomes crucial for clinicians to utilize genetic test as a diagnostic tool.
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Affiliation(s)
- Hongjia Du
- Department of Rheumatology and Immunology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Department of Fifth Internal Medicine, Chengdu Pidu District Hospital of Traditional Chinese Medicine, Chengdu, China
| | - Yan Chen
- Department of Rheumatology and Immunology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Department of Rheumatology and Immunology, Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
| | - Li Zeng
- Department of Neurology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Rui Wu
- Department of Rheumatology and Immunology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Department of Rheumatology and Immunology, Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
| | - Tong Wu
- Department of Rheumatology and Immunology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Department of Rheumatology and Immunology, Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
| | - Jing Zhu
- Department of Rheumatology and Immunology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Department of Rheumatology and Immunology, Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
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2
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Guo G, Wang L, Li X, Fu W, Cao J, Zhang J, Liu Y, Liu M, Wang M, Zhao G, Zhao X, Zhou Y, Niu S, Liu G, Zhang Y, Dong J, Tao H, Zhao X. Enhanced myofilament calcium sensitivity aggravates abnormal calcium handling and diastolic dysfunction in patient-specific induced pluripotent stem cell-derived cardiomyocytes with MYH7 mutation. Cell Calcium 2024; 117:102822. [PMID: 38101154 DOI: 10.1016/j.ceca.2023.102822] [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] [Received: 06/05/2023] [Revised: 10/04/2023] [Accepted: 11/06/2023] [Indexed: 12/17/2023]
Abstract
Hypertrophic cardiomyopathy (HCM), the most common inherited heart disease, is frequently caused by mutations in the β-cardiac myosin heavy chain gene (MYH7). Abnormal calcium handling and diastolic dysfunction are archetypical features of HCM caused by MYH7 gene mutations. However, the mechanism of how MYH7 mutations leads to these features remains unclear, which inhibits the development of effective therapies. Initially, cardiomyocytes were generated from induced pluripotent stem cells from an eight-year-old girl diagnosed with HCM carrying a MYH7(C.1063 G>A) heterozygous mutation(mutant-iPSC-CMs) and mutation-corrected isogenic iPSCs(control-iPSC-CMs) in the present study. Next, we compared phenotype of mutant-iPSC-CMs to that of control-iPSC-CMs, by assessing their morphology, hypertrophy-related genes expression, calcium handling, diastolic function and myofilament calcium sensitivity at days 15 and 40 respectively. Finally, to better understand increased myofilament Ca2+ sensitivity as a central mechanism of central pathogenicity in HCM, inhibition of calcium sensitivity with mavacamten can improveed cardiomyocyte hypertrophy. Mutant-iPSC-CMs exhibited enlarged areas, increased sarcomere disarray, enhanced expression of hypertrophy-related genes proteins, abnormal calcium handling, diastolic dysfunction and increased myofilament calcium sensitivity at day 40, but only significant increase in calcium sensitivity and mild diastolic dysfunction at day 15. Increased calcium sensitivity by levosimendan aggravates cardiomyocyte hypertrophy phenotypes such as expression of hypertrophy-related genes, abnormal calcium handling and diastolic dysfunction, while inhibition of calcium sensitivity significantly improves cardiomyocyte hypertrophy phenotypes in mutant-iPSC-CMs, suggesting increased myofilament calcium sensitivity is the primary mechanisms for MYH7 mutations pathogenesis. Our studies have uncovered a pathogenic mechanism of HCM caused by MYH7 gene mutations through which enhanced myofilament calcium sensitivity aggravates abnormal calcium handling and diastolic dysfunction. Correction of the myofilament calcium sensitivity was found to be an effective method for treating the development of HCM phenotype in vitro.
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Affiliation(s)
- Guangli Guo
- Department of Cardiology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, China
| | - Lu Wang
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Xiaowei Li
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China
| | - Wanrong Fu
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Jinhua Cao
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Jianchao Zhang
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Yangyang Liu
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China
| | - Mengduan Liu
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China
| | - Mengyu Wang
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China
| | - Guojun Zhao
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Xi Zhao
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China
| | - Yangfan Zhou
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China
| | - Shaohui Niu
- Department of Cardiology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, China
| | - Gangqiong Liu
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Yanzhou Zhang
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Jianzeng Dong
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China; Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, No. 2 Beijing Anzhen Road, Chaoyang District, Beijing 100029, China.
| | - Hailong Tao
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
| | - Xiaoyan Zhao
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China.
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3
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Mogharehabed F, Czubryt MP. The role of fibrosis in the pathophysiology of muscular dystrophy. Am J Physiol Cell Physiol 2023; 325:C1326-C1335. [PMID: 37781738 DOI: 10.1152/ajpcell.00196.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 09/25/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Muscular dystrophy exerts significant and dramatic impacts on affected patients, including progressive muscle wasting leading to lung and heart failure, and results in severely curtailed lifespan. Although the focus for many years has been on the dysfunction induced by the loss of function of dystrophin or related components of the striated muscle costamere, recent studies have demonstrated that accompanying pathologies, particularly muscle fibrosis, also contribute adversely to patient outcomes. A significant body of research has now shown that therapeutically targeting these accompanying pathologies via their underlying molecular mechanisms may provide novel approaches to patient management that can complement the current standard of care. In this review, we discuss the interplay between muscle fibrosis and muscular dystrophy pathology. A better understanding of these processes will contribute to improved patient care options, restoration of muscle function, and reduced patient morbidity and mortality.
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Affiliation(s)
- Farnaz Mogharehabed
- Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Michael P Czubryt
- Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
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4
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Landim-Vieira M, Ma W, Song T, Rastegarpouyani H, Gong H, Coscarella IL, Bogaards SJP, Conijn SP, Ottenheijm CAC, Hwang HS, Papadaki M, Knollmann BC, Sadayappan S, Irving TC, Galkin VE, Chase PB, Pinto JR. Cardiac troponin T N-domain variant destabilizes the actin interface resulting in disturbed myofilament function. Proc Natl Acad Sci U S A 2023; 120:e2221244120. [PMID: 37252999 PMCID: PMC10265946 DOI: 10.1073/pnas.2221244120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 05/04/2023] [Indexed: 06/01/2023] Open
Abstract
Missense variant Ile79Asn in human cardiac troponin T (cTnT-I79N) has been associated with hypertrophic cardiomyopathy and sudden cardiac arrest in juveniles. cTnT-I79N is located in the cTnT N-terminal (TnT1) loop region and is known for its pathological and prognostic relevance. A recent structural study revealed that I79 is part of a hydrophobic interface between the TnT1 loop and actin, which stabilizes the relaxed (OFF) state of the cardiac thin filament. Given the importance of understanding the role of TnT1 loop region in Ca2+ regulation of the cardiac thin filament along with the underlying mechanisms of cTnT-I79N-linked pathogenesis, we investigated the effects of cTnT-I79N on cardiac myofilament function. Transgenic I79N (Tg-I79N) muscle bundles displayed increased myofilament Ca2+ sensitivity, smaller myofilament lattice spacing, and slower crossbridge kinetics. These findings can be attributed to destabilization of the cardiac thin filament's relaxed state resulting in an increased number of crossbridges during Ca2+ activation. Additionally, in the low Ca2+-relaxed state (pCa8), we showed that more myosin heads are in the disordered-relaxed state (DRX) that are more likely to interact with actin in cTnT-I79N muscle bundles. Dysregulation of the myosin super-relaxed state (SRX) and the SRX/DRX equilibrium in cTnT-I79N muscle bundles likely result in increased mobility of myosin heads at pCa8, enhanced actomyosin interactions as evidenced by increased active force at low Ca2+, and increased sinusoidal stiffness. These findings point to a mechanism whereby cTnT-I79N weakens the interaction of the TnT1 loop with the actin filament, which in turn destabilizes the relaxed state of the cardiac thin filament.
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Affiliation(s)
- Maicon Landim-Vieira
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL32306
| | - Weikang Ma
- Department of Biology, Illinois Institute of Technology, Chicago, IL60616
| | - Taejeong Song
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH45267
| | - Hosna Rastegarpouyani
- Department of Biological Science, Florida State University, Tallahassee, FL32306
- Institude of Molecular Biophysics, Florida State University, Tallahassee, FL32306
| | - Henry Gong
- Department of Biology, Illinois Institute of Technology, Chicago, IL60616
| | - Isabella Leite Coscarella
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL32306
| | - Sylvia J. P. Bogaards
- Department of Physiology, Amsterdam University Medical Center, Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Stefan P. Conijn
- Department of Physiology, Amsterdam University Medical Center, Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Coen A. C. Ottenheijm
- Department of Physiology, Amsterdam University Medical Center, Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Hyun S. Hwang
- Department of Nutrition and Integrative Physiology, Florida State University, Tallahassee, FL32306
| | - Maria Papadaki
- Department of Cell and Molecular Physiology, Loyola University Chicago Stritch School of Medicine, Chicago, IL60153
| | - Bjorn C. Knollmann
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN37232
| | - Sakthivel Sadayappan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH45267
| | - Thomas C. Irving
- Department of Biology, Illinois Institute of Technology, Chicago, IL60616
| | - Vitold E. Galkin
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA23507
| | - P. Bryant Chase
- Department of Biological Science, Florida State University, Tallahassee, FL32306
| | - Jose Renato Pinto
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL32306
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Schmid S, Heim-Kupr B, Pérez-Schindler J, Mansingh S, Beer M, Mittal N, Ehrenfeuchter N, Handschin C. PGC-1β modulates catabolism and fiber atrophy in the fasting-response of specific skeletal muscle beds. Mol Metab 2022; 66:101643. [PMID: 36400401 PMCID: PMC9723918 DOI: 10.1016/j.molmet.2022.101643] [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] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 11/14/2022] [Accepted: 11/14/2022] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE Skeletal muscle is a pivotal organ for the coordination of systemic metabolism, constituting one of the largest storage site for glucose, lipids and amino acids. Tight temporal orchestration of protein breakdown in times of fasting has to be balanced with preservation of muscle mass and function. However, the molecular mechanisms that control the fasting response in muscle are poorly understood. METHODS We now have identified a role for the peroxisome proliferator-activated receptor γ coactivator 1β (PGC-1β) in the regulation of catabolic pathways in this context in muscle-specific loss-of-function mouse models. RESULTS Muscle-specific knockouts for PGC-1β experience mitigated muscle atrophy in fasting, linked to reduced expression of myostatin, atrogenes, activation of AMP-dependent protein kinase (AMPK) and other energy deprivation signaling pathways. At least in part, the muscle fasting response is modulated by a negative effect of PGC-1β on the nuclear factor of activated T-cells 1 (NFATC1). CONCLUSIONS Collectively, these data highlight the complex regulation of muscle metabolism and reveal a new role for muscle PGC-1β in the control of proteostasis in fasting.
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Affiliation(s)
- Svenia Schmid
- Biozentrum, University of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland
| | - Barbara Heim-Kupr
- Biozentrum, University of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland
| | | | - Shivani Mansingh
- Biozentrum, University of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland
| | - Markus Beer
- Biozentrum, University of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland
| | - Nitish Mittal
- Biozentrum, University of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland
| | | | - Christoph Handschin
- Biozentrum, University of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland.
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Guo Q, Wu S, Liang W, Tan J, Liu X, Yuan Y, Li X, Zhao H. Glabrol impurity exacerbates glabridin toxicity in zebrafish embryos by increasing myofibril disorganization. J Ethnopharmacol 2022; 287:114963. [PMID: 34971733 DOI: 10.1016/j.jep.2021.114963] [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] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 12/14/2021] [Accepted: 12/26/2021] [Indexed: 06/14/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Glabridin, extracted from Glycyrrhiza glabra L., is widely used for the treatment of hyperpigmentation because of its anti-inflammatory and antioxidant activities and its ability to inhibit melanin synthesis. This led to the strict regulation of its quality and safety. However, traditional quality control methods used for plant extracts cannot reflect the product quality owing to multiple unknown impurities, which necessitates the further analysis of impurities. AIM OF THE STUDY The study identified the toxic impurities of glabridin and their toxicological mechanism. MATERIALS AND METHODS In total, 10 glabridin samples from different sources were quantified using high-performance liquid chromatography. Sample toxicities were evaluated using zebrafish and cell models. To identify impurities, samples with different toxicity were analyzed by ultra-high-performance liquid chromatography coupled with quadrupole-Orbitrap mass spectrometry. The toxicity of related impurities was verified in the zebrafish model. Phalloidin stain was used to evaluate subtle changes in myofibril alignment. RESULTS Although glabridin content in the samples was similar, there were significant differences in toxicity. The results were verified using four different mammalian cell lines. Higher contents of glabrone and glabrol were identified in the sample with the highest toxicity. In the zebrafish model, the addition of glabrol reduced the LC50 of glabridin to 9.224, 6.229, and 5.370 μM at 48, 72, and 96 h post-fertilization, respectively, whereas glabrone did not have any toxic effect. Phalloidin staining indicated that a glabrol impurity exacerbates the myotoxicity of glabridin in zebrafish embryos. CONCLUSION Glabrol, but not glabrone, was identified as a key impurity that increased glabridin toxicity. This finding indicates that controlling glabrol content is necessary during glabridin product production.
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Affiliation(s)
- Qingquan Guo
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China
| | - Shaojuan Wu
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China
| | - Wenyao Liang
- Guangzhou Quality Supervision and Testing Institute, Guangzhou 511447, China
| | - Jianhua Tan
- Guangzhou Quality Supervision and Testing Institute, Guangzhou 511447, China
| | - Xiangmei Liu
- Guangzhou Quality Supervision and Testing Institute, Guangzhou 511447, China
| | - Yuxi Yuan
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China
| | - Xiaohong Li
- Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China
| | - Haishan Zhao
- Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China.
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Dobie R, West CC, Henderson BEP, Wilson-Kanamori JR, Markose D, Kitto LJ, Portman JR, Beltran M, Sohrabi S, Akram AR, Ramachandran P, Yong LY, Davidson D, Henderson NC. Deciphering Mesenchymal Drivers of Human Dupuytren's Disease at Single-Cell Level. J Invest Dermatol 2022; 142:114-123.e8. [PMID: 34274346 DOI: 10.1016/j.jid.2021.05.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 01/21/2023]
Abstract
Dupuytren's disease (DD) is a common, progressive fibroproliferative disease affecting the palmar fascia of the hands, causing fingers to irreversibly flex toward the palm with significant loss of function. Surgical treatments are limited; therefore, effective new therapies for DD are urgently required. To identify the key cellular and molecular pathways driving DD, we employed single-cell RNA sequencing, profiling the transcriptomes of 35,250 human single cells from DD, nonpathogenic fascia, and healthy dermis. We identify a DD-specific population of pathogenic PDPN+/FAP+ mesenchymal cells displaying an elevated expression of fibrillar collagens and profibrogenic genes. In silico trajectory analysis reveals resident fibroblasts to be the source of this pathogenic population. To resolve the processes governing DD progression, genes differentially expressed during fibroblast differentiation were identified, including upregulated TNFRSF12A and transcription factor SCX. Knockdown of SCX and blockade of TNFRSF12A inhibited the proliferation and altered the profibrotic gene expression of cultured human FAP+ mesenchymal cells, demonstrating a functional role for these genes in DD. The power of single-cell RNA sequencing is utilized to identify the major pathogenic mesenchymal subpopulations driving DD and the key molecular pathways regulating the DD-specific myofibroblast phenotype. Using this precision medicine approach, inhibition of TNFRSF12A has shown potential clinical utility in the treatment of DD.
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Affiliation(s)
- Ross Dobie
- Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh BioQuarter, The University of Edinburgh, Edinburgh, United Kingdom
| | - Chris C West
- Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh BioQuarter, The University of Edinburgh, Edinburgh, United Kingdom; Department of Plastic, Reconstructive and Burns Surgery, St John's Hospital, Livingston, United Kingdom; Department of Plastic, Reconstructive and Hand Surgery, Leeds General Infirmary, Leeds, United Kingdom
| | - Beth E P Henderson
- Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh BioQuarter, The University of Edinburgh, Edinburgh, United Kingdom
| | - John R Wilson-Kanamori
- Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh BioQuarter, The University of Edinburgh, Edinburgh, United Kingdom
| | - Dyana Markose
- Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh BioQuarter, The University of Edinburgh, Edinburgh, United Kingdom
| | - Laura J Kitto
- Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh BioQuarter, The University of Edinburgh, Edinburgh, United Kingdom
| | - Jordan R Portman
- Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh BioQuarter, The University of Edinburgh, Edinburgh, United Kingdom
| | - Mariana Beltran
- Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh BioQuarter, The University of Edinburgh, Edinburgh, United Kingdom
| | - Sadaf Sohrabi
- Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh BioQuarter, The University of Edinburgh, Edinburgh, United Kingdom
| | - Ahsan R Akram
- Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh BioQuarter, The University of Edinburgh, Edinburgh, United Kingdom
| | - Prakash Ramachandran
- Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh BioQuarter, The University of Edinburgh, Edinburgh, United Kingdom
| | - Li Yenn Yong
- Department of Plastic, Reconstructive and Burns Surgery, St John's Hospital, Livingston, United Kingdom
| | - Dominique Davidson
- Department of Plastic, Reconstructive and Burns Surgery, St John's Hospital, Livingston, United Kingdom
| | - Neil C Henderson
- Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh BioQuarter, The University of Edinburgh, Edinburgh, United Kingdom; MRC Human Genetics Unit, Institute of Genetics and Cancer, The University of Edinburgh, Edinburgh, United Kingdom.
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8
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Hortigon-Vinagre MP, Zamora V, Burton FL, Smith GL. The Use of Voltage Sensitive Dye di-4-ANEPPS and Video-Based Contractility Measurements to Assess Drug Effects on Excitation-Contraction Coupling in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes. J Cardiovasc Pharmacol 2021; 77:280-290. [PMID: 33109927 DOI: 10.1097/fjc.0000000000000937] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/09/2020] [Indexed: 12/21/2022]
Abstract
ABSTRACT Because cardiotoxicity is one of the leading causes of drug failure and attrition, the design of new protocols and technologies to assess proarrhythmic risks on cardiac cells is in continuous development by different laboratories. Current methodologies use electrical, intracellular Ca2+, or contractility assays to evaluate cardiotoxicity. Increasingly, the human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are the in vitro tissue model used in commercial assays because it is believed to recapitulate many aspects of human cardiac physiology. In this work, we demonstrate that the combination of a contractility and voltage measurements, using video-based imaging and fluorescence microscopy, on hiPSC-CMs allows the investigation of mechanistic links between electrical and mechanical effects in an assay design that can address medium throughput scales necessary for drug screening, offering a view of the mechanisms underlying drug toxicity. To assess the accuracy of this novel technique, 10 commercially available inotropic drugs were tested (5 positive and 5 negative). Included were drugs with simple and specific mechanisms, such as nifedipine, Bay K8644, and blebbistatin, and others with a more complex action such as isoproterenol, pimobendan, digoxin, and amrinone, among others. In addition, the results provide a mechanism for the toxicity of itraconazole in a human model, a drug with reported side effects on the heart. The data demonstrate a strong negative inotropic effect because of the blockade of L-type Ca2+ channels and additional action on the cardiac myofilaments. We can conclude that the combination of contractility and action potential measurements can provide wider mechanistic knowledge of drug cardiotoxicity for preclinical assays.
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MESH Headings
- Action Potentials/drug effects
- Arrhythmias, Cardiac/chemically induced
- Arrhythmias, Cardiac/metabolism
- Arrhythmias, Cardiac/physiopathology
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/metabolism
- Cardiotoxicity
- Cell Differentiation
- Cells, Cultured
- Excitation Contraction Coupling/drug effects
- Fluorescent Dyes/chemistry
- Humans
- Induced Pluripotent Stem Cells/drug effects
- Induced Pluripotent Stem Cells/metabolism
- Induced Pluripotent Stem Cells/pathology
- Microscopy, Fluorescence
- Microscopy, Video
- Myocardial Contraction/drug effects
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Myofibrils/drug effects
- Myofibrils/metabolism
- Myofibrils/pathology
- Pyridinium Compounds/chemistry
- Risk Assessment
- Time Factors
- Toxicity Tests
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Affiliation(s)
- Maria Pura Hortigon-Vinagre
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universdad de Extremadura, Badajoz, Spain
| | - Victor Zamora
- Departamento de Ingeniería Mecánica, Energética y de los Materiales, Escuela de Ingerierias Industriales, Universidad de Extremadura, Badajoz, Spain
| | - Francis L Burton
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom ; and
- Clyde Biosciences Ltd, BioCity Scotland, Newhouse, United Kingdom
| | - Godfrey L Smith
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom ; and
- Clyde Biosciences Ltd, BioCity Scotland, Newhouse, United Kingdom
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9
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Matboli M, Saad M, Hasanin AH, A Saleh L, Baher W, Bekhet MM, Eissa S. New insight into the role of isorhamnetin as a regulator of insulin signaling pathway in type 2 diabetes mellitus rat model: Molecular and computational approach. Biomed Pharmacother 2021; 135:111176. [PMID: 33401224 DOI: 10.1016/j.biopha.2020.111176] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [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: 11/10/2020] [Revised: 12/17/2020] [Accepted: 12/26/2020] [Indexed: 12/18/2022] Open
Abstract
We intended to examine the molecular mechanism of action of isorhamnetin (IHN) to regulate the pathway of insulin signaling. Molecular analysis, immunofluorescence, and histopathological examination were used to assess the anti-hyperglycemic and insulin resistance lowering effects of IHN in streptozotocin /high fat diet-induced type 2 diabetes using Wistar rats. At the microscopic level, treatment with IHN resulted in the restoration of myofibrils uniform arrangement and adipose tissue normal architecture. At the molecular level, treatment with IHN at three different doses showed a significant decrease in m-TOR, IGF1-R & LncRNA-RP11-773H22.4. expression and it up-regulated the expression of AKT2 mRNA, miR-1, and miR-3163 in both skeletal muscle and adipose tissue. At the protein level, IHN treated group showed a discrete spread with a moderate faint expression of m-TOR in skeletal muscles as well as adipose tissues. We concluded that IHN could be used in the in ameliorating insulin resistance associated with type 2 diabetes mellitus.
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MESH Headings
- Adipose Tissue/drug effects
- Adipose Tissue/metabolism
- Adipose Tissue/pathology
- Animals
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/enzymology
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/enzymology
- Diabetes Mellitus, Type 2/pathology
- Hypoglycemic Agents/pharmacology
- Insulin/blood
- Insulin Resistance
- Male
- MicroRNAs/genetics
- MicroRNAs/metabolism
- Myofibrils/drug effects
- Myofibrils/metabolism
- Myofibrils/pathology
- Proto-Oncogene Proteins c-akt/genetics
- Proto-Oncogene Proteins c-akt/metabolism
- Quercetin/analogs & derivatives
- Quercetin/pharmacology
- RNA, Long Noncoding/genetics
- RNA, Long Noncoding/metabolism
- Rats, Wistar
- Receptor, IGF Type 1/metabolism
- Signal Transduction
- TOR Serine-Threonine Kinases/metabolism
- Rats
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Affiliation(s)
- Marwa Matboli
- The Department of Medicinal Biochemistry and Molecular Biology, The School of Medicine, University of Ain Shams, Egypt; Biochemisty Department, Faculty of Medicine, Modern University for Technology and Information, Egypt.
| | - Maha Saad
- Biochemisty Department, Faculty of Medicine, Modern University for Technology and Information, Egypt
| | - Amany Helmy Hasanin
- Clinical Pharmacology Department, Faculty of Medicine, University of Ain Shams, Egypt
| | - Lobna A Saleh
- Clinical Pharmacology Department, Faculty of Medicine, University of Ain Shams, Egypt
| | - Walaa Baher
- The Department of Histology and Cell Biology, The School of Medicine, University of Ain Shams, Egypt
| | - Miram M Bekhet
- Diabetes and Endocrinology Unit, Internal Medicine Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Sanaa Eissa
- The Department of Medicinal Biochemistry and Molecular Biology, The School of Medicine, University of Ain Shams, Egypt.
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10
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Pavis GF, Jameson TSO, Dirks ML, Lee BP, Abdelrahman DR, Murton AJ, Porter C, Alamdari N, Mikus CR, Wall BT, Stephens FB. Improved recovery from skeletal muscle damage is largely unexplained by myofibrillar protein synthesis or inflammatory and regenerative gene expression pathways. Am J Physiol Endocrinol Metab 2021; 320:E291-E305. [PMID: 33284089 PMCID: PMC8260377 DOI: 10.1152/ajpendo.00454.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [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] [Indexed: 02/08/2023]
Abstract
The contribution of myofibrillar protein synthesis (MyoPS) to recovery from skeletal muscle damage in humans is unknown. Recreationally active men and women consumed a daily protein-polyphenol beverage targeted at increasing amino acid availability and reducing inflammation (PPB; n = 9), both known to affect MyoPS, or an isocaloric placebo (PLA; n = 9) during 168 h of recovery from 300 maximal unilateral eccentric contractions (EE). Muscle function was assessed daily. Muscle biopsies were collected for 24, 27, 36, 72, and 168 h for MyoPS measurements using 2H2O and expression of 224 genes using RT-qPCR and pathway analysis. PPB improved recovery of muscle function, which was impaired for 5 days after EE in PLA (interaction P < 0.05). Acute postprandial MyoPS rates were unaffected by nutritional intervention (24-27 h). EE increased overnight (27-36 h) MyoPS versus the control leg (PLA: 33 ± 19%; PPB: 79 ± 25%; leg P < 0.01), and PPB tended to increase this further (interaction P = 0.06). Daily MyoPS rates were greater with PPB between 72 and 168 h after EE, albeit after function had recovered. Inflammatory and regenerative signaling pathways were dramatically upregulated and clustered after EE but were unaffected by nutritional intervention. These results suggest that accelerated recovery from EE is not explained by elevated MyoPS or suppression of inflammation.NEW & NOTEWORTHY The present study investigated the contribution of myofibrillar protein synthesis (MyoPS) and associated gene signaling to recovery from 300 muscle-damaging, eccentric contractions. Measured with 2H2O, MyoPS rates were elevated during recovery and observed alongside expression of inflammatory and regenerative signaling pathways. A nutritional intervention accelerated recovery; however, MyoPS and gene signaling were unchanged compared with placebo. These data indicate that MyoPS and associated signaling do not explain accelerated recovery from muscle damage.
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Affiliation(s)
- George F Pavis
- Nutritional Physiology Group, Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Tom S O Jameson
- Nutritional Physiology Group, Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Marlou L Dirks
- Nutritional Physiology Group, Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Benjamin P Lee
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
| | - Doaa R Abdelrahman
- Department of Surgery, University of Texas Medical Branch, Galveston, Texas
| | - Andrew J Murton
- Department of Surgery, University of Texas Medical Branch, Galveston, Texas
| | - Craig Porter
- Department of Surgery, University of Texas Medical Branch, Galveston, Texas
| | | | | | - Benjamin T Wall
- Nutritional Physiology Group, Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Francis B Stephens
- Nutritional Physiology Group, Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
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11
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Schuldt M, Johnston JR, He H, Huurman R, Pei J, Harakalova M, Poggesi C, Michels M, Kuster DWD, Pinto JR, van der Velden J. Mutation location of HCM-causing troponin T mutations defines the degree of myofilament dysfunction in human cardiomyocytes. J Mol Cell Cardiol 2021; 150:77-90. [PMID: 33148509 PMCID: PMC10616699 DOI: 10.1016/j.yjmcc.2020.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 10/03/2020] [Accepted: 10/13/2020] [Indexed: 01/25/2023]
Abstract
BACKGROUND The clinical outcome of hypertrophic cardiomyopathy patients is not only determined by the disease-causing mutation but influenced by a variety of disease modifiers. Here, we defined the role of the mutation location and the mutant protein dose of the troponin T mutations I79N, R94C and R278C. METHODS AND RESULTS We determined myofilament function after troponin exchange in permeabilized single human cardiomyocytes as well as in cardiac patient samples harboring the R278C mutation. Notably, we found that a small dose of mutant protein is sufficient for the maximal effect on myofilament Ca2+-sensitivity for the I79N and R94C mutation while the mutation location determines the magnitude of this effect. While incorporation of I79N and R94C increased myofilament Ca2+-sensitivity, incorporation of R278C increased Ca2+-sensitivity at low and intermediate dose, while it decreased Ca2+-sensitivity at high dose. All three cTnT mutants showed reduced thin filament binding affinity, which coincided with a relatively low maximal exchange (50.5 ± 5.2%) of mutant troponin complex in cardiomyocytes. In accordance, 32.2 ± 4.0% mutant R278C was found in two patient samples which showed 50.0 ± 3.7% mutant mRNA. In accordance with studies that showed clinical variability in patients with the exact same mutation, we observed variability on the functional single cell level in patients with the R278C mutation. These differences in myofilament properties could not be explained by differences in the amount of mutant protein. CONCLUSIONS Using troponin exchange in single human cardiomyocytes, we show that TNNT2 mutation-induced changes in myofilament Ca2+-sensitivity depend on mutation location, while all mutants show reduced thin filament binding affinity. The specific mutation-effect observed for R278C could not be translated to myofilament function of cardiomyocytes from patients, and is most likely explained by other (post)-translational troponin modifications. Overall, our studies illustrate that mutation location underlies variability in myofilament Ca2+-sensitivity, while only the R278C mutation shows a highly dose-dependent effect on myofilament function.
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Affiliation(s)
- Maike Schuldt
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands.
| | - Jamie R Johnston
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA
| | - Huan He
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA; Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, USA
| | - Roy Huurman
- Department of Cardiology, Thorax Center, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Jiayi Pei
- Department of Cardiology, Division Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands; Regenerative Medicine Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Magdalena Harakalova
- Department of Cardiology, Division Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands; Regenerative Medicine Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Michelle Michels
- Department of Cardiology, Thorax Center, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Diederik W D Kuster
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Jose R Pinto
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA
| | - Jolanda van der Velden
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
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12
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Auxerre-Plantié E, Nielsen T, Grunert M, Olejniczak O, Perrot A, Özcelik C, Harries D, Matinmehr F, Dos Remedios C, Mühlfeld C, Kraft T, Bodmer R, Vogler G, Sperling SR. Identification of MYOM2 as a candidate gene in hypertrophic cardiomyopathy and Tetralogy of Fallot, and its functional evaluation in the Drosophila heart. Dis Model Mech 2020; 13:dmm045377. [PMID: 33033063 PMCID: PMC7758640 DOI: 10.1242/dmm.045377] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 10/01/2020] [Indexed: 01/11/2023] Open
Abstract
The causal genetic underpinnings of congenital heart diseases, which are often complex and multigenic, are still far from understood. Moreover, there are also predominantly monogenic heart defects, such as cardiomyopathies, with known disease genes for the majority of cases. In this study, we identified mutations in myomesin 2 (MYOM2) in patients with Tetralogy of Fallot (TOF), the most common cyanotic heart malformation, as well as in patients with hypertrophic cardiomyopathy (HCM), who do not exhibit any mutations in the known disease genes. MYOM2 is a major component of the myofibrillar M-band of the sarcomere, and a hub gene within interactions of sarcomere genes. We show that patient-derived cardiomyocytes exhibit myofibrillar disarray and reduced passive force with increasing sarcomere lengths. Moreover, our comprehensive functional analyses in the Drosophila animal model reveal that the so far uncharacterized fly gene CG14964 [herein referred to as Drosophila myomesin and myosin binding protein (dMnM)] may be an ortholog of MYOM2, as well as other myosin binding proteins. Its partial loss of function or moderate cardiac knockdown results in cardiac dilation, whereas more severely reduced function causes a constricted phenotype and an increase in sarcomere myosin protein. Moreover, compound heterozygous combinations of CG14964 and the sarcomere gene Mhc (MYH6/7) exhibited synergistic genetic interactions. In summary, our results suggest that MYOM2 not only plays a critical role in maintaining robust heart function but may also be a candidate gene for heart diseases such as HCM and TOF, as it is clearly involved in the development of the heart.This article has an associated First Person interview with Emilie Auxerre-Plantié and Tanja Nielsen, joint first authors of the paper.
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Affiliation(s)
- Emilie Auxerre-Plantié
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
| | - Tanja Nielsen
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Marcel Grunert
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Olga Olejniczak
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Andreas Perrot
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Experimental and Clinical Research Center, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
| | - Cemil Özcelik
- Experimental and Clinical Research Center, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
| | - Dennis Harries
- Medical School of Hannover, Institute of Molecular and Cell Physiology, 30625 Hannover, Germany
| | - Faramarz Matinmehr
- Medical School of Hannover, Institute of Molecular and Cell Physiology, 30625 Hannover, Germany
| | - Cristobal Dos Remedios
- Anatomy and Histology, School of Medical Sciences, Bosch Institute, University of Sydney, Camperdown, Sydney, New South Wales 2006, Australia
| | - Christian Mühlfeld
- Institute of Functional and Applied Anatomy, Hannover Medical School, 30625 Hannover, Germany
| | - Theresia Kraft
- Medical School of Hannover, Institute of Molecular and Cell Physiology, 30625 Hannover, Germany
| | - Rolf Bodmer
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Georg Vogler
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Silke R Sperling
- Cardiovascular Genetics, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
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13
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Alvarado G, Tóth A, Csősz É, Kalló G, Dankó K, Csernátony Z, Smith A, Gram M, Akerström B, Édes I, Balla G, Papp Z, Balla J. Heme-Induced Oxidation of Cysteine Groups of Myofilament Proteins Leads to Contractile Dysfunction of Permeabilized Human Skeletal Muscle Fibres. Int J Mol Sci 2020; 21:ijms21218172. [PMID: 33142923 PMCID: PMC7663642 DOI: 10.3390/ijms21218172] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/21/2020] [Accepted: 10/30/2020] [Indexed: 02/07/2023] Open
Abstract
Heme released from red blood cells targets a number of cell components including the cytoskeleton. The purpose of the present study was to determine the impact of free heme (20–300 µM) on human skeletal muscle fibres made available during orthopedic surgery. Isometric force production and oxidative protein modifications were monitored in permeabilized skeletal muscle fibre segments. A single heme exposure (20 µM) to muscle fibres decreased Ca2+-activated maximal (active) force (Fo) by about 50% and evoked an approximately 3-fold increase in Ca2+-independent (passive) force (Fpassive). Oxidation of sulfhydryl (SH) groups was detected in structural proteins (e.g., nebulin, α-actinin, meromyosin 2) and in contractile proteins (e.g., myosin heavy chain and myosin-binding protein C) as well as in titin in the presence of 300 µM heme. This SH oxidation was not reversed by dithiothreitol (50 mM). Sulfenic acid (SOH) formation was also detected in the structural proteins (nebulin, α-actinin, meromyosin). Heme effects on SH oxidation and SOH formation were prevented by hemopexin (Hpx) and α1-microglobulin (A1M). These data suggest that free heme has a significant impact on human skeletal muscle fibres, whereby oxidative alterations in structural and contractile proteins limit contractile function. This may explain and or contribute to the weakness and increase of skeletal muscle stiffness in chronic heart failure, rhabdomyolysis, and other hemolytic diseases. Therefore, therapeutic use of Hpx and A1M supplementation might be effective in preventing heme-induced skeletal muscle alterations.
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Affiliation(s)
- Gerardo Alvarado
- HAS-UD Vascular Biology and Myocardial Pathophysiology Research Group, Hungarian Academy of Sciences, H-4032 Debrecen, Hungary; (G.A.); (A.T.)
- Division of Clinical Physiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary;
| | - Attila Tóth
- HAS-UD Vascular Biology and Myocardial Pathophysiology Research Group, Hungarian Academy of Sciences, H-4032 Debrecen, Hungary; (G.A.); (A.T.)
- Division of Clinical Physiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary;
| | - Éva Csősz
- Proteomics Core Facility, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (É.C.); (G.K.)
| | - Gergő Kalló
- Proteomics Core Facility, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (É.C.); (G.K.)
| | - Katalin Dankó
- Department of Rheumatology, Institute of Internal Medicine, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary;
| | - Zoltán Csernátony
- Department of Orthopedics, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
| | - Ann Smith
- Department of Cell and Molecular Biology and Biochemistry, School of Biological and Chemical Sciences, University of Missouri-Kansas City, Missouri, MO 64110, USA;
| | - Magnus Gram
- Department of Clinical Sciences Lund, Pediatrics, Lund University, 22184 Lund, Sweden;
| | - Bo Akerström
- Department of Clinical Sciences Lund, Infection Medicine, Lund University, 22184 Lund, Sweden;
| | - István Édes
- Division of Clinical Physiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary;
| | - György Balla
- Institute of Pediatrics, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
| | - Zoltán Papp
- HAS-UD Vascular Biology and Myocardial Pathophysiology Research Group, Hungarian Academy of Sciences, H-4032 Debrecen, Hungary; (G.A.); (A.T.)
- Division of Clinical Physiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary;
- Correspondence: (Z.P.); (J.B.); Tel./Fax: +36-(52)-411717 (Z.P.); +36-(52)-413653 (J.B.)
| | - József Balla
- HAS-UD Vascular Biology and Myocardial Pathophysiology Research Group, Hungarian Academy of Sciences, H-4032 Debrecen, Hungary; (G.A.); (A.T.)
- Department of Nephrology, Institute of Medicine, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Hungary
- Correspondence: (Z.P.); (J.B.); Tel./Fax: +36-(52)-411717 (Z.P.); +36-(52)-413653 (J.B.)
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14
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Campanale CM, Scherrer B, Afacan O, Majeed A, Warfield SK, Sanders SP. Myofiber organization in the failing systemic right ventricle. J Cardiovasc Magn Reson 2020; 22:49. [PMID: 32600420 PMCID: PMC7322876 DOI: 10.1186/s12968-020-00637-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 05/13/2020] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The right ventricle (RV) often fails when functioning as the systemic ventricle, but the cause is not understood. We tested the hypothesis that myofiber organization is abnormal in the failing systemic right ventricle. METHODS We used diffusion-weighted cardiovascular magnetic resonance imaging to examine 3 failing hearts explanted from young patients with a systemic RV and one structurally normal heart with postnatally acquired RV hypertrophy for comparison. Diffusion compartment imaging was computed to separate the free diffusive component representing free water from an anisotropic component characterizing the orientation and diffusion characteristics of myofibers. The orientation of each anisotropic compartment was displayed in glyph format and used for qualitative description of myofibers and for construction of tractograms. The helix angle was calculated across the ventricular walls in 5 locations and displayed graphically. Scalar parameters (fractional anisotropy and mean diffusivity) were compared among specimens. RESULTS The hypertrophied systemic RV has an inner layer, comprising about 2/3 of the wall, composed of hypertrophied trabeculae and an epicardial layer of circumferential myofibers. Myofibers within smaller trabeculae are aligned and organized with parallel fibers while larger, composite bundles show marked disarray, largely between component trabeculae. We observed a narrow range of helix angles in the outer, compact part of the wall consistent with aligned, approximately circumferential fibers. However, there was marked variation of helix angle in the inner, trabecular part of the wall consistent with marked variation in fiber orientation. The apical whorl was disrupted or incomplete and we observed myocardial whorls or vortices at other locations. Fractional anisotropy was lower in abnormal hearts while mean diffusivity was more variable, being higher in 2 but lower in 1 heart, compared to the structurally normal heart. CONCLUSIONS Myofiber organization is abnormal in the failing systemic RV and might be an important substrate for heart failure and arrhythmia. It is unclear if myofiber disorganization is due to hemodynamic factors, developmental problems, or both.
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MESH Headings
- Adolescent
- Child, Preschool
- Diffusion Magnetic Resonance Imaging
- Female
- Heart Defects, Congenital/diagnostic imaging
- Heart Defects, Congenital/pathology
- Heart Defects, Congenital/physiopathology
- Heart Defects, Congenital/surgery
- Heart Failure/diagnostic imaging
- Heart Failure/pathology
- Heart Failure/physiopathology
- Heart Failure/surgery
- Heart Transplantation
- Heart Ventricles/diagnostic imaging
- Heart Ventricles/pathology
- Heart Ventricles/physiopathology
- Heart Ventricles/surgery
- Humans
- Male
- Myocardium/pathology
- Myofibrils/pathology
- Predictive Value of Tests
- Ventricular Dysfunction, Right/diagnostic imaging
- Ventricular Dysfunction, Right/pathology
- Ventricular Dysfunction, Right/physiopathology
- Ventricular Dysfunction, Right/surgery
- Ventricular Function, Right
- Young Adult
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Affiliation(s)
- Cosimo M. Campanale
- Unit of Perinatal Cardiology, Department of Neonatology, Ospedale Pediatrico Bambino Gesù di Roma, Rome, Italy
| | - Benoit Scherrer
- Department of Radiology, Boston Children’s Hospital and Harvard Medical School, Boston, MA USA
| | - Onur Afacan
- Department of Radiology, Boston Children’s Hospital and Harvard Medical School, Boston, MA USA
| | - Amara Majeed
- Department of Cardiology, Boston Children’s Hospital and Department of Pediatrics, Harvard Medical School, Boston, MA USA
| | - Simon K. Warfield
- Department of Radiology, Boston Children’s Hospital and Harvard Medical School, Boston, MA USA
| | - Stephen P. Sanders
- Cardiac Registry, Departments of Cardiology, Pathology and Cardiac Surgery, Boston Children’s Hospital, 300 Longwood Ave, Boston, MA 02115, USA. and Department of Pediatrics, Harvard Medical School, Boston, MA USA
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15
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Earle AJ, Kirby TJ, Fedorchak GR, Isermann P, Patel J, Iruvanti S, Moore SA, Bonne G, Wallrath LL, Lammerding J. Mutant lamins cause nuclear envelope rupture and DNA damage in skeletal muscle cells. Nat Mater 2020; 19:464-473. [PMID: 31844279 PMCID: PMC7102937 DOI: 10.1038/s41563-019-0563-5] [Citation(s) in RCA: 125] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 11/12/2019] [Indexed: 05/19/2023]
Abstract
Mutations in the LMNA gene, which encodes the nuclear envelope (NE) proteins lamins A/C, cause Emery-Dreifuss muscular dystrophy, congenital muscular dystrophy and other diseases collectively known as laminopathies. The mechanisms responsible for these diseases remain incompletely understood. Using three mouse models of muscle laminopathies and muscle biopsies from individuals with LMNA-related muscular dystrophy, we found that Lmna mutations reduced nuclear stability and caused transient rupture of the NE in skeletal muscle cells, resulting in DNA damage, DNA damage response activation and reduced cell viability. NE and DNA damage resulted from nuclear migration during skeletal muscle maturation and correlated with disease severity in the mouse models. Reduction of cytoskeletal forces on the myonuclei prevented NE damage and rescued myofibre function and viability in Lmna mutant myofibres, indicating that myofibre dysfunction is the result of mechanically induced NE damage. Taken together, these findings implicate mechanically induced DNA damage as a pathogenic contributor to LMNA skeletal muscle diseases.
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Affiliation(s)
- Ashley J Earle
- Meinig School of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Tyler J Kirby
- Meinig School of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Gregory R Fedorchak
- Meinig School of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Philipp Isermann
- Meinig School of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Jineet Patel
- Meinig School of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Sushruta Iruvanti
- Meinig School of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Steven A Moore
- Department of Pathology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Gisèle Bonne
- Sorbonne Université, Inserm UMRS 974, Center of Research in Myology, Association Institute of Myology, Paris, France
| | - Lori L Wallrath
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Jan Lammerding
- Meinig School of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA.
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Power AS, Norman R, Jones TLM, Hickey AJ, Ward ML. Mitochondrial function remains impaired in the hypertrophied right ventricle of pulmonary hypertensive rats following short duration metoprolol treatment. PLoS One 2019; 14:e0214740. [PMID: 30964911 PMCID: PMC6456253 DOI: 10.1371/journal.pone.0214740] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 03/19/2019] [Indexed: 12/16/2022] Open
Abstract
Pulmonary hypertension (PH) increases the work of the right ventricle (RV) and causes right-sided heart failure. This study examined RV mitochondrial function and ADP transfer in PH animals advancing to right heart failure, and investigated a potential therapy with the specific β1-adrenergic-blocker metoprolol. Adult Wistar rats (317 ± 4 g) were injected either with monocrotaline (MCT, 60 mg kg-1) to induce PH, or with an equivalent volume of saline for controls (CON). At three weeks post-injection the MCT rats began oral metoprolol (10 mg kg-1 day-1-) or placebo treatment until heart failure was observed in the MCT group. Mitochondrial function was then measured using high-resolution respirometry from permeabilised RV fibres. Relative to controls, MCT animals had impaired mitochondrial function but maintained coupling between myofibrillar ATPases and mitochondria, despite an increase in ADP diffusion distances. Cardiomyocytes from the RV of MCT rats were enlarged, primarily due to an increase in myofibrillar protein. The ratio of mitochondria per myofilament area was decreased in both MCT groups (p ≤ 0.05) in comparison to control (CON: 1.03 ± 0.04; MCT: 0.74 ± 0.04; MCT + BB: 0.74 ± 0.03). This not only implicates impaired energy production in PH, but also increases the diffusion distance for metabolites within the MCT cardiomyocytes, adding an additional hindrance to energy supply. Together, these changes may limit energy supply in MCT rat hearts, particularly at high cardiac workloads. Metoprolol treatment did not delay the onset of heart failure symptoms, improve mitochondrial function, or regress RV hypertrophy.
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Affiliation(s)
- Amelia S. Power
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
- * E-mail: (M-L W); (ASP)
| | - Ruth Norman
- School of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Timothy L. M. Jones
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Anthony J. Hickey
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Marie-Louise Ward
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
- * E-mail: (M-L W); (ASP)
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Duran P, Ward S, Christman KL, Alperin M. Mechanical impact of parturition-related strains on rat pelvic striated sphincters. Neurourol Urodyn 2019; 38:912-919. [PMID: 30779377 PMCID: PMC6431564 DOI: 10.1002/nau.23946] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/11/2019] [Accepted: 01/18/2019] [Indexed: 11/08/2022]
Abstract
AIMS To define the operational resting sarcomere length (Ls ) of the female rat external urethral sphincter (EUS) and external anal sphincter (EAS) and to determine the mechanism of parturition-related injury of EUS and EAS using a simulated birth injury (SBI) vaginal distention model. METHODS EUS and EAS of 3-month-old Sprague-Dawley control and injured rats were fixed in situ, harvested, and microdissected for Ls measurements and assessment of ultrastructure. EUS and EAS function was determined at baseline, and immediately and 4 weeks after SBI, using leak point pressure (LPP) and anorectal manometry (ARM), respectively. Operational L s was compared to species-specific optimal L s using one sample Student's t test. Data (mean ± SD) were compared between groups and time points using repeated measures one-way analysis of variance, followed by Tukey's post hoc pairwise comparisons, with significance set to 0.05. RESULTS The operational resting Ls of both sphincters (EUS: 2.09 ± 0.07 µm, EAS: 2.02 ± 0.03 µm) was significantly shorter than optimal rat Ls of 2.4 µm. Strains imposed on EUS and EAS during SBI resulted in significant sarcomere elongation and disruption, compared with the controls (EUS: 3.09 ± 0.11 µm, EAS: 3.37 ± 0.09 µm). Paralleling structural changes, LPP and ARM measures were significantly lower immediately (LPP: 21.5 ± 1.0 cmH2 O, ARM: 5.1 ± 2.31 cmH2 O) and 4 weeks (LPP: 27.7 ± 1.3cmH2 O, ARM: 2.5 ± 1.0 cmH2 O) after SBI relative to the baseline (LPP: 43.4 ± 8.5 cmH2 O, ARM: 8.2 ± 2.0 cmH2 O); P < 0.05. CONCLUSIONS Analogous to humans, the short resting Ls of rat EUS and EAS favors their sphincteric function. The insult experienced by these muscles during parturition leads to sarcomere hyperelongation, myofibrillar disruption, and dysfunction of the sphincters long-term.
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Affiliation(s)
- Pamela Duran
- Department of Bioengineering, Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, CA
| | - Samuel Ward
- Department of Orthopaedic Surgery, University of California San Diego, La Jolla, CA
- Department of Radiology, University of California San Diego, La Jolla, CA
| | - Karen L. Christman
- Department of Bioengineering, Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, CA
| | - Marianna Alperin
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Division of Female Pelvic Medicine and Reconstructive Surgery, University of California San Diego, La Jolla, CA
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18
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Robinson P, Liu X, Sparrow A, Patel S, Zhang YH, Casadei B, Watkins H, Redwood C. Hypertrophic cardiomyopathy mutations increase myofilament Ca 2+ buffering, alter intracellular Ca 2+ handling, and stimulate Ca 2+-dependent signaling. J Biol Chem 2018; 293:10487-10499. [PMID: 29760186 PMCID: PMC6036197 DOI: 10.1074/jbc.ra118.002081] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 05/03/2018] [Indexed: 11/06/2022] Open
Abstract
Mutations in thin filament regulatory proteins that cause hypertrophic cardiomyopathy (HCM) increase myofilament Ca2+ sensitivity. Mouse models exhibit increased Ca2+ buffering and arrhythmias, and we hypothesized that these changes are primary effects of the mutations (independent of compensatory changes) and that increased Ca2+ buffering and altered Ca2+ handling contribute to HCM pathogenesis via activation of Ca2+-dependent signaling. Here, we determined the primary effects of HCM mutations on intracellular Ca2+ handling and Ca2+-dependent signaling in a model system possessing Ca2+-handling mechanisms and contractile protein isoforms closely mirroring the human environment in the absence of potentially confounding remodeling. Using adenovirus, we expressed HCM-causing variants of human troponin-T, troponin-I, and α-tropomyosin (R92Q, R145G, and D175N, respectively) in isolated guinea pig left ventricular cardiomyocytes. After 48 h, each variant had localized to the I-band and comprised ∼50% of the total protein. HCM mutations significantly lowered the Kd of Ca2+ binding, resulting in higher Ca2+ buffering of mutant cardiomyocytes. We observed increased diastolic [Ca2+] and slowed Ca2+ reuptake, coupled with a significant decrease in basal sarcomere length and slowed relaxation. HCM mutant cells had higher sodium/calcium exchanger activity, sarcoplasmic reticulum Ca2+ load, and sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2) activity driven by Ca2+/calmodulin-dependent protein kinase II (CaMKII) phosphorylation of phospholamban. The ryanodine receptor (RyR) leak/load relationship was also increased, driven by CaMKII-mediated RyR phosphorylation. Altered Ca2+ homeostasis also increased signaling via both calcineurin/NFAT and extracellular signal-regulated kinase pathways. Altered myofilament Ca2+ buffering is the primary initiator of signaling cascades, indicating that directly targeting myofilament Ca2+ sensitivity provides an attractive therapeutic approach in HCM.
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Affiliation(s)
- Paul Robinson
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Xing Liu
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Alexander Sparrow
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Suketu Patel
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Yin-Hua Zhang
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Barbara Casadei
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Hugh Watkins
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Charles Redwood
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
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19
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Schänzer A, Rupp S, Gräf S, Zengeler D, Jux C, Akintürk H, Gulatz L, Mazhari N, Acker T, Van Coster R, Garvalov BK, Hahn A. Dysregulated autophagy in restrictive cardiomyopathy due to Pro209Leu mutation in BAG3. Mol Genet Metab 2018; 123:388-399. [PMID: 29338979 DOI: 10.1016/j.ymgme.2018.01.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [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: 09/25/2017] [Revised: 01/02/2018] [Accepted: 01/02/2018] [Indexed: 12/13/2022]
Abstract
Myofibrillary myopathies (MFM) are hereditary myopathies histologically characterized by degeneration of myofibrils and aggregation of proteins in striated muscle. Cardiomyopathy is common in MFM but the pathophysiological mechanisms are not well understood. The BAG3-Pro209Leu mutation is associated with early onset MFM and severe restrictive cardiomyopathy (RCM), often necessitating heart transplantation during childhood. We report on a young male patient with a BAG3-Pro209Leu mutation who underwent heart transplantation at eight years of age. Detailed morphological analyses of the explanted heart tissue showed intracytoplasmic inclusions, aggregation of BAG3 and desmin, disintegration of myofibers and Z-disk alterations. The presence of undegraded autophagosomes, seen by electron microscopy, as well as increased levels of p62, LC3-I and WIPI1, detected by immunohistochemistry and western blot analyses, indicated a dysregulation of autophagy. Parkin and PINK1, proteins involved in mitophagy, were slightly increased whereas mitochondrial OXPHOS activities were not altered. These findings indicate that altered autophagy plays a role in the pathogenesis and rapid progression of RCM in MFM caused by the BAG3-Pro209Leu mutation, which could have implications for future therapeutic strategies.
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Affiliation(s)
- A Schänzer
- Institute of Neuropathology, Justus Liebig University Giessen, 35392 Giessen, Germany.
| | - S Rupp
- Pediatric Heart Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - S Gräf
- Institute of Neuropathology, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - D Zengeler
- Center for Genomics and Transcriptomics (CeGat) GmbH, 72076 Tübingen, Germany
| | - C Jux
- Pediatric Heart Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - H Akintürk
- Pediatric Heart Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - L Gulatz
- Institute of Neuropathology, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - N Mazhari
- Pediatric Heart Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - T Acker
- Institute of Neuropathology, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - R Van Coster
- Division of Child Neurology, Department of Pediatrics, University Hospital Gent, 9000 Gent, Belgium
| | - B K Garvalov
- Institute of Neuropathology, Justus Liebig University Giessen, 35392 Giessen, Germany; Department of Microvascular Biology and Pathobiology, Centre for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany
| | - A Hahn
- Department of Child Neurology, Justus Liebig University Giessen, 35392 Giessen, Germany
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20
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Guaricci AI, Bulzis G, Pontone G, Scicchitano P, Carbonara R, Rabbat M, De Santis D, Ciccone MM. Current interpretation of myocardial stunning. Trends Cardiovasc Med 2017; 28:263-271. [PMID: 29221768 DOI: 10.1016/j.tcm.2017.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [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: 07/23/2017] [Revised: 11/16/2017] [Accepted: 11/19/2017] [Indexed: 12/11/2022]
Abstract
Myocardial stunning is a temporary post-ischemic cardiac mechanical dysfunction. As such, it is a heterogeneous entity and different conditions can promote its occurrence. Transient coronary occlusion, increased production of catecholamines and endothelin, and myocardial inflammation are all possible causes of myocardial stunning. Possible underlying mechanisms include an oxyradical hypothesis, calcium overload, decreased responsiveness of myofilaments to calcium, and excitation-contraction uncoupling due to sarcoplasmic reticulum dysfunction. The aim of this review is to summarize the clinical conditions that may be responsible for stunned myocardium.
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Affiliation(s)
- Andrea Igoren Guaricci
- Institute of Cardiovascular Disease, Department of Emergency and Organ Transplantation, University Hospital "Policlinico" of Bari, Bari, Italy; Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy.
| | - Gabriella Bulzis
- Institute of Cardiovascular Disease, Department of Emergency and Organ Transplantation, University Hospital "Policlinico" of Bari, Bari, Italy
| | | | | | - Rossella Carbonara
- Institute of Cardiovascular Disease, Department of Emergency and Organ Transplantation, University Hospital "Policlinico" of Bari, Bari, Italy
| | - Mark Rabbat
- Loyola University of Chicago, Chicago, IL; Edward Hines Jr. VA Hospital, Hines, IL
| | - Delia De Santis
- Institute of Cardiovascular Disease, Department of Emergency and Organ Transplantation, University Hospital "Policlinico" of Bari, Bari, Italy
| | - Marco Matteo Ciccone
- Institute of Cardiovascular Disease, Department of Emergency and Organ Transplantation, University Hospital "Policlinico" of Bari, Bari, Italy
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21
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Pingel J, Nielsen MS, Lauridsen T, Rix K, Bech M, Alkjaer T, Andersen IT, Nielsen JB, Feidenhansl R. Injection of high dose botulinum-toxin A leads to impaired skeletal muscle function and damage of the fibrilar and non-fibrilar structures. Sci Rep 2017; 7:14746. [PMID: 29116170 PMCID: PMC5677119 DOI: 10.1038/s41598-017-14997-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 10/20/2017] [Indexed: 12/30/2022] Open
Abstract
Botulinum-toxin A (BoNT/A) is used for a wide range of conditions. Intramuscular administration of BoNT/A inhibits the release of acetylcholine at the neuromuscular junction from presynaptic motor neurons causing muscle-paralysis. The aim of the present study was to investigate the effect of high dose intramuscular BoNT/A injections (6 UI = 60 pg) on muscle tissue. The gait pattern of the rats was significantly affected 3 weeks after BoNT/A injection. The ankle joint rotated externally, the rats became flat footed, and the stride length decreased after BoNT/A injection. Additionally, there was clear evidence of microstructural changes on the tissue level by as evidenced by 3D imaging of the muscles by Synchrotron Radiation X-ray Tomographic Microscopy (SRXTM). Both the fibrillar and the non-fibrillar tissues were affected. The volume fraction of fibrillary tissue was reduced significantly and the non-fibrillar tissue increased. This was accompanied by a loss of the linear structure of the muscle tissue. Furthermore, gene expression analysis showed a significant upregulation of COL1A1, MMP-2, TGF-b1, IL-6, MHCIIA and MHCIIx in the BoNT/A injected leg, while MHVIIB was significantly downregulated. IN CONCLUSION The present study reveals that high dose intramuscular BoNT/A injections cause microstructural damage of the muscle tissue, which contributes to impaired gait.
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Affiliation(s)
- Jessica Pingel
- Center for Neuroscience, University of Copenhagen, Copenhagen, Denmark.
| | | | | | - Kristian Rix
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Martin Bech
- Medical Radiation Physics, Clinical Sciences, Lund University, Lund, Sweden
| | - Tine Alkjaer
- Center for Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Ida Torp Andersen
- Center for Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bo Nielsen
- Center for Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - R Feidenhansl
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
- European XFEL, Hamburg, Germany
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22
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Ferrantini C, Coppini R, Pioner JM, Gentile F, Tosi B, Mazzoni L, Scellini B, Piroddi N, Laurino A, Santini L, Spinelli V, Sacconi L, De Tombe P, Moore R, Tardiff J, Mugelli A, Olivotto I, Cerbai E, Tesi C, Poggesi C. Pathogenesis of Hypertrophic Cardiomyopathy is Mutation Rather Than Disease Specific: A Comparison of the Cardiac Troponin T E163R and R92Q Mouse Models. J Am Heart Assoc 2017; 6:JAHA.116.005407. [PMID: 28735292 PMCID: PMC5586279 DOI: 10.1161/jaha.116.005407] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background In cardiomyocytes from patients with hypertrophic cardiomyopathy, mechanical dysfunction and arrhythmogenicity are caused by mutation‐driven changes in myofilament function combined with excitation‐contraction (E‐C) coupling abnormalities related to adverse remodeling. Whether myofilament or E‐C coupling alterations are more relevant in disease development is unknown. Here, we aim to investigate whether the relative roles of myofilament dysfunction and E‐C coupling remodeling in determining the hypertrophic cardiomyopathy phenotype are mutation specific. Methods and Results Two hypertrophic cardiomyopathy mouse models carrying the R92Q and the E163R TNNT2 mutations were investigated. Echocardiography showed left ventricular hypertrophy, enhanced contractility, and diastolic dysfunction in both models; however, these phenotypes were more pronounced in the R92Q mice. Both E163R and R92Q trabeculae showed prolonged twitch relaxation and increased occurrence of premature beats. In E163R ventricular myofibrils or skinned trabeculae, relaxation following Ca2+ removal was prolonged; resting tension and resting ATPase were higher; and isometric ATPase at maximal Ca2+ activation, the energy cost of tension generation, and myofilament Ca2+ sensitivity were increased compared with that in wild‐type mice. No sarcomeric changes were observed in R92Q versus wild‐type mice, except for a large increase in myofilament Ca2+ sensitivity. In R92Q myocardium, we found a blunted response to inotropic interventions, slower decay of Ca2+ transients, reduced SERCA function, and increased Ca2+/calmodulin kinase II activity. Contrarily, secondary alterations of E‐C coupling and signaling were minimal in E163R myocardium. Conclusions In E163R models, mutation‐driven myofilament abnormalities directly cause myocardial dysfunction. In R92Q, diastolic dysfunction and arrhythmogenicity are mediated by profound cardiomyocyte signaling and E‐C coupling changes. Similar hypertrophic cardiomyopathy phenotypes can be generated through different pathways, implying different strategies for a precision medicine approach to treatment.
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MESH Headings
- Animals
- Calcium Signaling
- Calcium-Calmodulin-Dependent Protein Kinases/metabolism
- Cardiomyopathy, Hypertrophic/diagnostic imaging
- Cardiomyopathy, Hypertrophic/genetics
- Cardiomyopathy, Hypertrophic/metabolism
- Cardiomyopathy, Hypertrophic/physiopathology
- Disease Models, Animal
- Excitation Contraction Coupling
- Fibrosis
- Genetic Markers
- Genetic Predisposition to Disease
- Hypertrophy, Left Ventricular/diagnostic imaging
- Hypertrophy, Left Ventricular/genetics
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/physiopathology
- Male
- Mice, Inbred C57BL
- Mice, Transgenic
- Mutation
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Myofibrils/metabolism
- Myofibrils/pathology
- Phenotype
- Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism
- Troponin T/genetics
- Ventricular Dysfunction, Left/diagnostic imaging
- Ventricular Dysfunction, Left/genetics
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Function, Left
- Ventricular Remodeling
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Affiliation(s)
- Cecilia Ferrantini
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | | | - Josè Manuel Pioner
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Francesca Gentile
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Benedetta Tosi
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Luca Mazzoni
- Department of NeuroFarBa, University of Florence, Italy
| | - Beatrice Scellini
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Nicoletta Piroddi
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | | | | | | | - Leonardo Sacconi
- LENS, University of Florence & National Institute of Optics (INO-CNR), Florence, Italy
| | - Pieter De Tombe
- Loyola University Medical Center Department of Physiology, Chicago, IL
| | | | | | - Alessandro Mugelli
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | | | | | - Chiara Tesi
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Italy
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23
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McKee KK, Crosson SC, Meinen S, Reinhard JR, Rüegg MA, Yurchenco PD. Chimeric protein repair of laminin polymerization ameliorates muscular dystrophy phenotype. J Clin Invest 2017; 127:1075-1089. [PMID: 28218617 DOI: 10.1172/jci90854] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 12/30/2016] [Indexed: 12/28/2022] Open
Abstract
Mutations in laminin α2-subunit (Lmα2, encoded by LAMA2) are linked to approximately 30% of congenital muscular dystrophy cases. Mice with a homozygous mutation in Lama2 (dy2J mice) express a nonpolymerizing form of laminin-211 (Lm211) and are a model for ambulatory-type Lmα2-deficient muscular dystrophy. Here, we developed transgenic dy2J mice with muscle-specific expression of αLNNd, a laminin/nidogen chimeric protein that provides a missing polymerization domain. Muscle-specific expression of αLNNd in dy2J mice resulted in strong amelioration of the dystrophic phenotype, manifested by the prevention of fibrosis and restoration of forelimb grip strength. αLNNd also restored myofiber shape, size, and numbers to control levels in dy2J mice. Laminin immunostaining and quantitation of tissue extractions revealed increased Lm211 expression in αLNNd-transgenic dy2J mice. In cultured myotubes, we determined that αLNNd expression increased myotube surface accumulation of polymerization-deficient recombinant laminins, with retention of collagen IV, reiterating the basement membrane (BM) changes observed in vivo. Laminin LN domain mutations linked to several of the Lmα2-deficient muscular dystrophies are predicted to compromise polymerization. The data herein support the hypothesis that engineered expression of αLNNd can overcome polymerization deficits to increase laminin, stabilize BM structure, and substantially ameliorate muscular dystrophy.
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Abstract
Calcium is a crucial mediator of cell signaling in skeletal muscles for basic cellular functions and specific functions, including contraction, fiber-type differentiation and energy production. The sarcoplasmic reticulum (SR) is an organelle that provides a large supply of intracellular Ca2+ in myofibers. Upon excitation, it releases Ca2+ into the cytosol, inducing contraction of myofibrils. During relaxation, it takes up cytosolic Ca2+ to terminate the contraction. During exercise, Ca2+ is cycled between the cytosol and the SR through a system by which the Ca2+ pool in the SR is restored by uptake of extracellular Ca2+ via a specific channel on the plasma membrane. This channel is called the store-operated Ca2+ channel or the Ca2+ release-activated Ca2+ channel. It is activated by depletion of the Ca2+ store in the SR by coordination of two main molecules: stromal interaction molecule 1 (STIM1) and calcium release-activated calcium channel protein 1 (ORAI1). Recently, myopathies with a dominant mutation in these genes have been reported and the pathogenic mechanism of such diseases have been proposed. This review overviews the calcium signaling in skeletal muscles and role of store-operated Ca2+ entry in calcium homeostasis. Finally, we discuss the phenotypes and the pathomechanism of myopathies caused by mutations in the STIM1 and ORAI1 genes.
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Affiliation(s)
- Jong-Mok Lee
- Department of Genome Medicine Development, Medical Genome Center, National Center of Neurology and Neuropsychiatry, Kodaira, Tokyo 187-8551, Japan.
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Neuropsychiatry, Kodaira, Tokyo 187-8502, Japan.
| | - Satoru Noguchi
- Department of Genome Medicine Development, Medical Genome Center, National Center of Neurology and Neuropsychiatry, Kodaira, Tokyo 187-8551, Japan.
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Neuropsychiatry, Kodaira, Tokyo 187-8502, Japan.
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Abstract
The diagnosis of malignant melanoma can be difficult because these tumors can be amelanotic and may contain diverse variants and divergent differentiations, of which the signet-ring cell subtype is very rare and has only been described in humans, dogs, cats, and a hamster. We describe herein histopathologic and immunohistochemical approaches taken to diagnose a case of signet-ring cell malignant melanoma with myofibroblastic differentiation in a cat. A tumor within the abdominal skin of a 2-year-old cat was composed of signet-ring cells and irregularly interwoven streams of spindle cells. Both neoplastic cell types were periodic-acid-Schiff, Fontana, and Sudan black B negative. Signet-ring cells strongly expressed vimentin and S100 protein. Spindle cells strongly expressed vimentin and smooth muscle actin; some cells expressed S100, moderately neuron-specific enolase, and others variably actin and desmin. A few round cells expressed melan A, and a few plump spindle cells expressed melan A and PNL2, confirming the diagnosis of amelanotic signet-ring cell malignant melanoma with myofibroblastic differentiation in a cat. Differential diagnoses were excluded, including signet-ring cell forms of adenocarcinomas, lymphomas, liposarcomas, leiomyosarcomas, squamous cell carcinomas, basal cell carcinomas, and adnexal tumors.
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Affiliation(s)
- Manuela Hirz
- Institut für Veterinär-Pathologie, Justus-Liebig-Universität Giessen, Giessen, Germany
| | - Christiane Herden
- Institut für Veterinär-Pathologie, Justus-Liebig-Universität Giessen, Giessen, Germany
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Novoselov VP, Savchenko SV, Porvin AN, Koshlyak DA, Nadev AP, Ageeva TA, Chikinev YV, Polyakevich AS. Ultrastructure of Cardiomyocytes and Blood Capillary Endotheliocytes in the Myocardium under Conditions of Experimental Mechanical Injury to the Heart. Bull Exp Biol Med 2016; 161:134-6. [PMID: 27259494 DOI: 10.1007/s10517-016-3363-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [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: 05/02/2015] [Indexed: 11/25/2022]
Abstract
We studied ultrastructural changes in cardiomyocytes and blood capillary endotheliocytes in the ventricular myocardium in response to mechanical injury of the heart of varying severity in Wistar rats. Acute alterative changes in cardiomyocyte and endotheliocyte ultrastructure indicate impairment of the energy-producing, contractile, and protein-synthesizing functions of the cells after mechanical injury. These disorders play the key role in the development of acute contractile insufficiency of the myocardium in mechanical injury to the heart.
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Affiliation(s)
- V P Novoselov
- Department of Forensic Medicine, Novosibirsk State Medical University, Novosibirsk, Russia
| | - S V Savchenko
- Department of Forensic Medicine, Novosibirsk State Medical University, Novosibirsk, Russia.
| | - A N Porvin
- Department of Forensic Medicine, Novosibirsk State Medical University, Novosibirsk, Russia
| | - D A Koshlyak
- Department of Forensic Medicine, Novosibirsk State Medical University, Novosibirsk, Russia
| | - A P Nadev
- Department of Pathology, Novosibirsk State Medical University, Novosibirsk, Russia
| | - T A Ageeva
- Department of Pathology, Novosibirsk State Medical University, Novosibirsk, Russia
| | - Yu V Chikinev
- Department of Hospital and Pediatric Surgery, Novosibirsk State Medical University, Novosibirsk, Russia
| | - A S Polyakevich
- Department of Hospital and Pediatric Surgery, Novosibirsk State Medical University, Novosibirsk, Russia
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Tu Y, Wang Y, Ding L, Zhang J, Wu W. Development of a Novel Thyroid Function Fluctuated Animal Model for Thyroid-Associated Ophthalmopathy. PLoS One 2016; 11:e0148595. [PMID: 26872324 PMCID: PMC4752469 DOI: 10.1371/journal.pone.0148595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 01/21/2016] [Indexed: 11/18/2022] Open
Abstract
Background The establishment of a suitable and stable animal model is critical for research on thyroid-associated ophthalmopathy (TAO). In clinical practice, we found that patients treated with I-131 often exhibit TAO; therefore, we aimed to establish a novel thyroid function fluctuated animal model of TAO by simulating the clinical treatment process. Methods We treated SD rats with I-131 to damage the thyroid and then used sodium levothyroxine (L-T4) to supplement the thyroid hormone (TH) levels every seven days, leading to a fluctuating level of thyroid hormones that simulated the status of clinical TAO patients. Rats administered normal saline were considered as a control. The weight, intraocular pressure, and serum T3, T4, TSH and TRAb levels of the rats were measured, and the pathological changes were analyzed by H&E staining and transmission electron microscopy (TEM). Results The experimental rats (TAO group) exhibited significantly reduced weight and elevated intraocular pressure compared with the control rats. Meanwhile, the serum levels of T3 and T4 were up-regulated in the TAO group, but the TSH level decreased during the 10-week study. Moreover, increased numbers of blood vessels and inflammatory cell infiltrations were observed in the orbital tissues of the TAO rats, while no abnormal changes occurred in the control rats. The orbital myofibrils in the TAO rats appeared fractured and dissolved, with twisted structures. Mitochondrial swelling and vacuoles within the endoplasmic reticulum, swelling nerve fibers, shedding nerve myelin, and macrophages were found in the TAO group. Conclusion Rats treated with I-131 and sodium levothyroxine exhibited characteristics similar to those of TAO patients in the clinic, providing an effective and simple method for the establishment of a stable animal model for research on the pathogenesis and treatment of TAO.
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Affiliation(s)
- Yunhai Tu
- The Eye Hospital of Wenzhou Medical University, Wenzhou, 325000, PR China
| | - Yilong Wang
- Department of Laboratory Animal Center, Wenzhou Medical University, Wenzhou, 325000, PR China
| | - Luna Ding
- The Eye Hospital of Wenzhou Medical University, Wenzhou, 325000, PR China
| | - Jiao Zhang
- The Eye Hospital of Wenzhou Medical University, Wenzhou, 325000, PR China
| | - Wencan Wu
- The Eye Hospital of Wenzhou Medical University, Wenzhou, 325000, PR China
- * E-mail:
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Bengoechea R, Pittman SK, Tuck EP, True HL, Weihl CC. Myofibrillar disruption and RNA-binding protein aggregation in a mouse model of limb-girdle muscular dystrophy 1D. Hum Mol Genet 2015; 24:6588-602. [PMID: 26362252 PMCID: PMC4634370 DOI: 10.1093/hmg/ddv363] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 09/02/2015] [Accepted: 09/02/2015] [Indexed: 12/15/2022] Open
Abstract
Limb-girdle muscular dystrophy type 1D (LGMD1D) is caused by dominantly inherited missense mutations in DNAJB6, an Hsp40 co-chaperone. LGMD1D muscle has rimmed vacuoles and inclusion bodies containing DNAJB6, Z-disc proteins and TDP-43. DNAJB6 is expressed as two isoforms; DNAJB6a and DNAJB6b. Both isoforms contain LGMD1D mutant residues and are expressed in human muscle. To identify which mutant isoform confers disease pathogenesis and generate a mouse model of LGMD1D, we evaluated DNAJB6 expression and localization in skeletal muscle as well as generating DNAJB6 isoform specific expressing transgenic mice. DNAJB6a localized to myonuclei while DNAJB6b was sarcoplasmic. LGMD1D mutations in DNAJB6a or DNAJB6b did not alter this localization in mouse muscle. Transgenic mice expressing the LGMD1D mutant, F93L, in DNAJB6b under a muscle-specific promoter became weak, had early lethality and developed muscle pathology consistent with myopathy after 2 months; whereas mice expressing the same F93L mutation in DNAJB6a or overexpressing DNAJB6a or DNAJB6b wild-type transgenes remained unaffected after 1 year. DNAJB6b localized to the Z-disc and DNAJB6b-F93L expressing mouse muscle had myofibrillar disorganization and desmin inclusions. Consistent with DNAJB6 dysfunction, keratin 8/18, a DNAJB6 client also accumulated in DNAJB6b-F93L expressing mouse muscle. The RNA-binding proteins hnRNPA1 and hnRNPA2/B1 accumulated and co-localized with DNAJB6 at sarcoplasmic stress granules suggesting that these proteins maybe novel DNAJB6b clients. Similarly, hnRNPA1 and hnRNPA2/B1 formed sarcoplasmic aggregates in patients with LGMD1D. Our data support that LGMD1D mutations in DNAJB6 disrupt its sarcoplasmic function suggesting a role for DNAJB6b in Z-disc organization and stress granule kinetics.
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Affiliation(s)
| | | | | | - Heather L True
- Department of Cell Biology and Physiology and and The Hope Center for Neurological Diseases, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Conrad C Weihl
- Department of Neurology, The Hope Center for Neurological Diseases, Washington University School of Medicine, St Louis, MO 63110, USA
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Ishii K, Suzuki N, Mabuchi Y, Ito N, Kikura N, Fukada S, Okano H, Takeda S, Akazawa C. Muscle Satellite Cell Protein Teneurin-4 Regulates Differentiation During Muscle Regeneration. Stem Cells 2015; 33:3017-27. [PMID: 26013034 PMCID: PMC4744701 DOI: 10.1002/stem.2058] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 04/30/2015] [Indexed: 02/06/2023]
Abstract
Satellite cells are maintained in an undifferentiated quiescent state, but during muscle regeneration they acquire an activated stage, and initiate to proliferate and differentiate as myoblasts. The transmembrane protein teneurin-4 (Ten-4) is specifically expressed in the quiescent satellite cells; however, its cellular and molecular functions remain unknown. We therefore aimed to elucidate the function of Ten-4 in muscle satellite cells. In the tibialis anterior (TA) muscle of Ten-4-deficient mice, the number and the size of myofibers, as well as the population of satellite cells, were reduced with/without induction of muscle regeneration. Furthermore, we found an accelerated activation of satellite cells in the regenerated Ten-4-deficient TA muscle. The cell culture analysis using primary satellite cells showed that Ten-4 suppressed the progression of myogenic differentiation. Together, our findings revealed that Ten-4 functions as a crucial player in maintaining the quiescence of muscle satellite cells.
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Affiliation(s)
- Kana Ishii
- Department of Biochemistry and BiophysicsGraduate School of Health Care Sciences, Tokyo Medical and Dental UniversityTokyoJapan
| | - Nobuharu Suzuki
- Department of Biochemistry and BiophysicsGraduate School of Health Care Sciences, Tokyo Medical and Dental UniversityTokyoJapan
| | - Yo Mabuchi
- Department of Biochemistry and BiophysicsGraduate School of Health Care Sciences, Tokyo Medical and Dental UniversityTokyoJapan
| | - Naoki Ito
- Department of Molecular TherapyNational Institute of Neuroscience, National Center of Neurology and PsychiatryKodairaTokyoJapan
| | - Naomi Kikura
- Department of Biochemistry and BiophysicsGraduate School of Health Care Sciences, Tokyo Medical and Dental UniversityTokyoJapan
| | - So‐ichiro Fukada
- Laboratory of Molecular and Cellular PhysiologyGraduate School of Pharmaceutical Sciences, Osaka UniversitySuitaOsakaJapan
| | - Hideyuki Okano
- Department of PhysiologyKeio University School of MedicineShinjuku‐kuTokyoJapan
| | - Shin'ichi Takeda
- Department of Molecular TherapyNational Institute of Neuroscience, National Center of Neurology and PsychiatryKodairaTokyoJapan
| | - Chihiro Akazawa
- Department of Biochemistry and BiophysicsGraduate School of Health Care Sciences, Tokyo Medical and Dental UniversityTokyoJapan
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Mendias CL, Roche SM, Harning JA, Davis ME, Lynch EB, Sibilsky Enselman ER, Jacobson JA, Claflin DR, Calve S, Bedi A. Reduced muscle fiber force production and disrupted myofibril architecture in patients with chronic rotator cuff tears. J Shoulder Elbow Surg 2015; 24:111-9. [PMID: 25193488 DOI: 10.1016/j.jse.2014.06.037] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [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: 04/05/2014] [Revised: 05/28/2014] [Accepted: 06/09/2014] [Indexed: 02/01/2023]
Abstract
BACKGROUND A persistent atrophy of muscle fibers and an accumulation of fat, collectively referred to as fatty degeneration, commonly occur in patients with chronic rotator cuff tears. The etiology of fatty degeneration and function of the residual rotator cuff musculature have not been well characterized in humans. We hypothesized that muscles from patients with chronic rotator cuff tears have reduced muscle fiber force production, disordered myofibrils, and an accumulation of fat vacuoles. METHODS The contractility of muscle fibers from biopsy specimens of supraspinatus muscles of 13 patients with chronic full-thickness posterosuperior rotator cuff tears was measured and compared with data from healthy vastus lateralis muscle fibers. Correlations between muscle fiber contractility, American Shoulder and Elbow Surgeons (ASES) scores, and tear size were analyzed. Histology and electron microscopy were also performed. RESULTS Torn supraspinatus muscles had a 30% reduction in maximum isometric force production and a 29% reduction in normalized force compared with controls. Normalized supraspinatus fiber force positively correlated with ASES score and negatively correlated with tear size. Disordered sarcomeres were noted, along with an accumulation of lipid-laden macrophages in the extracellular matrix surrounding supraspinatus muscle fibers. CONCLUSIONS Patients with chronic supraspinatus tears have significant reductions in muscle fiber force production. Force production also correlates with ASES scores and tear size. The structural and functional muscle dysfunction of the residual muscle fibers is independent of the additional area taken up by fibrotic tissue. This work may help establish future therapies to restore muscle function after the repair of chronically torn rotator cuff muscles.
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Affiliation(s)
- Christopher L Mendias
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Stuart M Roche
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Julie A Harning
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Max E Davis
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Evan B Lynch
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Jon A Jacobson
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Dennis R Claflin
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Surgery, Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Sarah Calve
- School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Asheesh Bedi
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
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Yuen M, Sandaradura SA, Dowling JJ, Kostyukova AS, Moroz N, Quinlan KG, Lehtokari VL, Ravenscroft G, Todd EJ, Ceyhan-Birsoy O, Gokhin DS, Maluenda J, Lek M, Nolent F, Pappas CT, Novak SM, D'Amico A, Malfatti E, Thomas BP, Gabriel SB, Gupta N, Daly MJ, Ilkovski B, Houweling PJ, Davidson AE, Swanson LC, Brownstein CA, Gupta VA, Medne L, Shannon P, Martin N, Bick DP, Flisberg A, Holmberg E, Van den Bergh P, Lapunzina P, Waddell LB, Sloboda DD, Bertini E, Chitayat D, Telfer WR, Laquerrière A, Gregorio CC, Ottenheijm CAC, Bönnemann CG, Pelin K, Beggs AH, Hayashi YK, Romero NB, Laing NG, Nishino I, Wallgren-Pettersson C, Melki J, Fowler VM, MacArthur DG, North KN, Clarke NF. Leiomodin-3 dysfunction results in thin filament disorganization and nemaline myopathy. J Clin Invest 2014; 124:4693-708. [PMID: 25250574 DOI: 10.1172/jci75199] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 08/19/2014] [Indexed: 01/02/2023] Open
Abstract
Nemaline myopathy (NM) is a genetic muscle disorder characterized by muscle dysfunction and electron-dense protein accumulations (nemaline bodies) in myofibers. Pathogenic mutations have been described in 9 genes to date, but the genetic basis remains unknown in many cases. Here, using an approach that combined whole-exome sequencing (WES) and Sanger sequencing, we identified homozygous or compound heterozygous variants in LMOD3 in 21 patients from 14 families with severe, usually lethal, NM. LMOD3 encodes leiomodin-3 (LMOD3), a 65-kDa protein expressed in skeletal and cardiac muscle. LMOD3 was expressed from early stages of muscle differentiation; localized to actin thin filaments, with enrichment near the pointed ends; and had strong actin filament-nucleating activity. Loss of LMOD3 in patient muscle resulted in shortening and disorganization of thin filaments. Knockdown of lmod3 in zebrafish replicated NM-associated functional and pathological phenotypes. Together, these findings indicate that mutations in the gene encoding LMOD3 underlie congenital myopathy and demonstrate that LMOD3 is essential for the organization of sarcomeric thin filaments in skeletal muscle.
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Fabrisia A, Elke B, Donna S, Ricardo F, Bret G, Bridget D, Giovanna D, Alexandra R, Amin C, Yesica G, Aaron B. Arsenic induces sustained impairment of skeletal muscle and muscle progenitor cell ultrastructure and bioenergetics. Free Radic Biol Med 2014; 74:64-73. [PMID: 24960579 PMCID: PMC4159748 DOI: 10.1016/j.freeradbiomed.2014.06.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 05/20/2014] [Accepted: 06/17/2014] [Indexed: 02/07/2023]
Abstract
Over 4 million individuals in the United States, and over 140 million individuals worldwide, are exposed daily to arsenic-contaminated drinking water. Human exposures can range from below the current limit of 10 μg/L to over 1mg/L, with 100 μg/L promoting disease in a large portion of those exposed. Although increased attention has recently been paid to myopathy following arsenic exposure, the pathogenic mechanisms underlying clinical symptoms remain poorly understood. This study tested the hypothesis that arsenic induces lasting muscle mitochondrial dysfunction and impairs metabolism. Compared to nonexposed controls, mice exposed to drinking water containing 100 μg/L arsenite for 5 weeks demonstrated impaired muscle function, mitochondrial myopathy, and altered oxygen consumption that were concomitant with increased mitochondrial fusion gene transcription. There were no differences in the levels of inorganic arsenic or its monomethyl and dimethyl metabolites between controls and exposed muscles, confirming that arsenic does not accumulate in muscle. Nevertheless, muscle progenitor cells isolated from exposed mice recapitulated the aberrant myofiber phenotype and were more resistant to oxidative stress, generated more reactive oxygen species, and displayed autophagic mitochondrial morphology, compared to cells isolated from nonexposed mice. These pathological changes from a possible maladaptive oxidative stress response provide insight into declines in muscle functioning caused by exposure to this common environmental contaminant.
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Affiliation(s)
- Ambrosio Fabrisia
- Department of Physical Medicine & Rehabilitation,
University of Pittsburgh, Pittsburgh, PA 15219
| | - Brown Elke
- Department of Physical Medicine & Rehabilitation,
University of Pittsburgh, Pittsburgh, PA 15219,
| | - Stolz Donna
- Department of Cell Biology, University of Pittsburgh, Pittsburgh,
PA 15213,
| | - Ferrari Ricardo
- Department of Physical Medicine & Rehabilitation,
University of Pittsburgh, Pittsburgh, PA,
| | - Goodpaster Bret
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA
15213,
| | - Deasy Bridget
- Department of Orthopaedic Surgery, University of Pittsburgh,
Pittsburgh, PA 15213,
| | - Distefano Giovanna
- Department of Physical Therapy, University of Pittsburgh,
Pittsburgh, PA, 15213,
| | - Roperti Alexandra
- Department of Bioengineering, University of Pittsburgh, Pittsburgh,
PA, 15213,
| | - Cheikhi Amin
- Department of Environmental and Occupational Health, University of
Pittsburgh, Pittsburgh, PA, 15219,
| | - Garciafigueroa Yesica
- Department of Environmental and Occupational Health, University of
Pittsburgh, Pittsburgh, PA, 15219,
| | - Barchowsky Aaron
- Department of Environmental and Occupational Health, University of
Pittsburgh, Pittsburgh, PA, 15219,
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Witjas-Paalberends ER, Piroddi N, Stam K, van Dijk SJ, Oliviera VS, Ferrara C, Scellini B, Hazebroek M, ten Cate FJ, van Slegtenhorst M, dos Remedios C, Niessen HWM, Tesi C, Stienen GJM, Heymans S, Michels M, Poggesi C, van der Velden J. Mutations in MYH7 reduce the force generating capacity of sarcomeres in human familial hypertrophic cardiomyopathy. Cardiovasc Res 2013; 99:432-41. [PMID: 23674513 DOI: 10.1093/cvr/cvt119] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [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] [Indexed: 11/14/2022] Open
Abstract
AIMS Familial hypertrophic cardiomyopathy (HCM), frequently caused by sarcomeric gene mutations, is characterized by cellular dysfunction and asymmetric left-ventricular (LV) hypertrophy. We studied whether cellular dysfunction is due to an intrinsic sarcomere defect or cardiomyocyte remodelling. METHODS AND RESULTS Cardiac samples from 43 sarcomere mutation-positive patients (HCMmut: mutations in thick (MYBPC3, MYH7) and thin (TPM1, TNNI3, TNNT2) myofilament genes) were compared with 14 sarcomere mutation-negative patients (HCMsmn), eight patients with secondary LV hypertrophy due to aortic stenosis (LVHao) and 13 donors. Force measurements in single membrane-permeabilized cardiomyocytes revealed significantly lower maximal force generating capacity (Fmax) in HCMmut (21 ± 1 kN/m²) and HCMsmn (26 ± 3 kN/m²) compared with donor (36 ± 2 kN/m²). Cardiomyocyte remodelling was more severe in HCMmut compared with HCMsmn based on significantly lower myofibril density (49 ± 2 vs. 63 ± 5%) and significantly higher cardiomyocyte area (915 ± 15 vs. 612 ± 11 μm²). Low Fmax in MYBPC3mut, TNNI3mut, HCMsmn, and LVHao was normalized to donor values after correction for myofibril density. However, Fmax was significantly lower in MYH7mut, TPM1mut, and TNNT2mut even after correction for myofibril density. In accordance, measurements in single myofibrils showed very low Fmax in MYH7mut, TPM1mut, and TNNT2mut compared with donor (respectively, 73 ± 3, 70 ± 7, 83 ± 6, and 113 ± 5 kN/m²). In addition, force was lower in MYH7mut cardiomyocytes compared with MYBPC3mut, HCMsmn, and donor at submaximal [Ca²⁺]. CONCLUSION Low cardiomyocyte Fmax in HCM patients is largely explained by hypertrophy and reduced myofibril density. MYH7 mutations reduce force generating capacity of sarcomeres at maximal and submaximal [Ca²⁺]. These hypocontractile sarcomeres may represent the primary abnormality in patients with MYH7 mutations.
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Affiliation(s)
- E Rosalie Witjas-Paalberends
- Laboratory for Physiology, VU University Medical Center, Institute for Cardiovascular Research, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
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Venkataraman R, Baldo MP, Hwang HS, Veltri T, Pinto JR, Baudenbacher FJ, Knollmann BC. Myofilament calcium de-sensitization and contractile uncoupling prevent pause-triggered ventricular tachycardia in mouse hearts with chronic myocardial infarction. J Mol Cell Cardiol 2013; 60:8-15. [PMID: 23570978 DOI: 10.1016/j.yjmcc.2013.03.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 03/11/2013] [Accepted: 03/30/2013] [Indexed: 11/16/2022]
Abstract
Myocardial infarction (MI) is a major risk for ventricular arrhythmia. Pause-triggered ventricular arrhythmia can be caused by increased myofilament Ca binding due to sarcomeric mutations or Ca-sensitizing compounds. Myofilament Ca sensitivity is also increased after MI. Here we hypothesize that MI increases risk for pause-triggered ventricular arrhythmias, which can be prevented by myofilament Ca-desensitization and contractile uncoupling. To test this hypothesis, we generated a murine chronic MI model using male B6SJLF1/J mice (n=40) that underwent permanent ligation of the left anterior descending coronary artery. 4 weeks post MI, cardiac structure, function and myofilament Ca sensitivity were evaluated. Pause-dependent arrhythmia susceptibility was quantified in isolated hearts with pacing trains of increasing frequency, followed by a pause and an extra stimulus. Coronary ligation resulted in a mean infarct size of 39.6±5.7% LV and fractional shortening on echocardiography was reduced by 40% compared to non-infarcted controls. Myofilament Ca sensitivity was significantly increased in post MI hearts (pCa50: Control=5.66±0.03; MI=5.84±0.05; P<0.01). Exposure to the Ca desensitizer/contractile uncoupler blebbistatin (BLEB, 3 μM) reduced myofilament Ca sensitivity of MI hearts to that of control hearts and selectively reduced the frequency of post-pause ectopic beats (MI 0.12±0.04 vs MI+BLEB 0.01±0.005 PVC/pause; P=0.02). BLEB also reduced the incidence of ventricular tachycardia in chronic MI hearts from 59% to 10% (P<0.05). We conclude that chronic MI hearts exhibit increased myofilament Ca sensitivity and pause-triggered ventricular arrhythmias, which can be prevented by blebbistatin. Decreasing myofilament Ca sensitivity may be a strategy to reduce arrhythmia burden after MI.
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Affiliation(s)
- Raghav Venkataraman
- Department of Biomedical Engineering and Physics, Vanderbilt University, Nashville, TN 37232-0575, USA
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Esposito A, Campana L, Palmisano A, De Cobelli F, Canu T, Santarella F, Colantoni C, Monno A, Vezzoli M, Pezzetti G, Manfredi AA, Rovere-Querini P, Del Maschio A. Magnetic resonance imaging at 7T reveals common events in age-related sarcopenia and in the homeostatic response to muscle sterile injury. PLoS One 2013; 8:e59308. [PMID: 23555016 PMCID: PMC3595251 DOI: 10.1371/journal.pone.0059308] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Accepted: 02/15/2013] [Indexed: 01/01/2023] Open
Abstract
Skeletal muscle remodeling in response to various noxae physiologically includes structural changes and inflammatory events. The possibility to study those phenomena in-vivo has been hampered by the lack of validated imaging tools. In our study, we have relied on multiparametric magnetic resonance imaging for quantitative monitoring of muscle changes in mice experiencing age-related sarcopenia or active regeneration after sterile acute injury of tibialis anterior muscle induced by cardiotoxin (CTX) injection. The extent of myofibrils’ necrosis, leukocyte infiltration, and regeneration have been evaluated and compared with parameters from magnetic resonance imaging: T2-mapping (T2 relaxation time; T2-rt), diffusion-tensor imaging (fractional anisotropy, F.A.) and diffusion weighted imaging (apparent diffusion coefficient, ADC). Inflammatory leukocytes within the perimysium and heterogeneous size of fibers characterized aged muscles. They displayed significantly increased T2-rt (P<0.05) and F.A. (P<0.05) compared with young muscles. After acute damage T2-rt increased in otherwise healthy young muscles with a peak at day 3, followed by a progressive decrease to basal values. F.A. dropped 24 hours after injury and afterward increased above the basal level in the regenerated muscle (from day 7 to day 15) returning to the basal value at the end of the follow up period. The ADC displayed opposite kinetics. T2-rt positively correlated with the number of infiltrating leucocytes retrieved by immunomagnetic bead sorting from the tissue (r = 0.92) and with the damage/infiltration score (r = 0.88) while F.A. correlated with the extent of tissue regeneration evaluated at various time points after injury (r = 0.88). Our results indicate that multiparametric MRI is a sensitive and informative tool for monitoring inflammatory and structural muscle changes in living experimental animals; particularly, it allows identifying the increase of T2-rt and F.A. as common events reflecting inflammatory infiltration and muscle regeneration in the transient response of the tissue to acute injury and in the persistent adaptation to aging.
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Affiliation(s)
- Antonio Esposito
- Department of Radiology and Preclinical MR and US Facility of Experimental Imaging Center, San Raffaele Scientific Institute, Milano, Italy.
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Sanbe A. [Small heat shock protein related diseases and acetylated tubulin]. Seikagaku 2013; 85:13-20. [PMID: 23469714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Affiliation(s)
- Atsushi Sanbe
- Department of Pharmacotherapeutics, School of Pharmacy, Iwate Medical University, 2-1-1 Nishitokuda Yahaba-cho, Shiwa-gun, Iwate 028-3694, Japan
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Badawoud MH, Hassan SM. Effects of exposure to lead on the peripheral motor system of the rat. An ultrastructural study. Neurosciences (Riyadh) 2013; 18:52-57. [PMID: 23291798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
OBJECTIVE To investigate the morphological changes in the peripheral motor system of the rat induced by exposure to lead. METHODS This study was conducted at the Anatomy Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia from January 2011 to January 2012. Female adult albino rats (n=10) were given lead acetate in their drinking water (500mg/L) for a period of 30 days. Female adult albino rats (n=5) were used as control. The soleus and gastrocnemius muscles were dissected and processed for electron microscopy. RESULTS Lead administration induced morphological changes in all constituents of the peripheral motor system of the rat, including; extension of long processes by Schwann cells, engorgement of nerve terminals, withdrawal of some terminals, and muscle fiber alterations. CONCLUSION Lead toxicity is detrimental to all constituents of the peripheral motor system of the rat. The histopathological changes explain some of the clinical manifestations of lead toxicity.
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Affiliation(s)
- Mohammed H Badawoud
- Department of Anatomy, Faculty of Medicine, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia.
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Mekkaoui C, Huang S, Chen HH, Dai G, Reese TG, Kostis WJ, Thiagalingam A, Maurovich-Horvat P, Ruskin JN, Hoffmann U, Jackowski MP, Sosnovik DE. Fiber architecture in remodeled myocardium revealed with a quantitative diffusion CMR tractography framework and histological validation. J Cardiovasc Magn Reson 2012; 14:70. [PMID: 23061749 PMCID: PMC3506570 DOI: 10.1186/1532-429x-14-70] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 10/01/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The study of myofiber reorganization in the remote zone after myocardial infarction has been performed in 2D. Microstructural reorganization in remodeled hearts, however, can only be fully appreciated by considering myofibers as continuous 3D entities. The aim of this study was therefore to develop a technique for quantitative 3D diffusion CMR tractography of the heart, and to apply this method to quantify fiber architecture in the remote zone of remodeled hearts. METHODS Diffusion Tensor CMR of normal human, sheep, and rat hearts, as well as infarcted sheep hearts was performed ex vivo. Fiber tracts were generated with a fourth-order Runge-Kutta integration technique and classified statistically by the median, mean, maximum, or minimum helix angle (HA) along the tract. An index of tract coherence was derived from the relationship between these HA statistics. Histological validation was performed using phase-contrast microscopy. RESULTS In normal hearts, the subendocardial and subepicardial myofibers had a positive and negative HA, respectively, forming a symmetric distribution around the midmyocardium. However, in the remote zone of the infarcted hearts, a significant positive shift in HA was observed. The ratio between negative and positive HA variance was reduced from 0.96 ± 0.16 in normal hearts to 0.22 ± 0.08 in the remote zone of the remodeled hearts (p < 0.05). This was confirmed histologically by the reduction of HA in the subepicardium from -52.03° ± 2.94° in normal hearts to -37.48° ± 4.05° in the remote zone of the remodeled hearts (p < 0.05). CONCLUSIONS A significant reorganization of the 3D fiber continuum is observed in the remote zone of remodeled hearts. The positive (rightward) shift in HA in the remote zone is greatest in the subepicardium, but involves all layers of the myocardium. Tractography-based quantification, performed here for the first time in remodeled hearts, may provide a framework for assessing regional changes in the left ventricle following infarction.
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Affiliation(s)
- Choukri Mekkaoui
- Athinoula A. Martinos Center For Biomedical Imaging, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Shuning Huang
- Athinoula A. Martinos Center For Biomedical Imaging, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Howard H Chen
- Athinoula A. Martinos Center For Biomedical Imaging, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Guangping Dai
- Athinoula A. Martinos Center For Biomedical Imaging, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Timothy G Reese
- Athinoula A. Martinos Center For Biomedical Imaging, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - William J Kostis
- Athinoula A. Martinos Center For Biomedical Imaging, Boston, MA, USA
- Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Aravinda Thiagalingam
- Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Pal Maurovich-Horvat
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jeremy N Ruskin
- Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Udo Hoffmann
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Marcel P Jackowski
- Department of Computer Science, Institute of Mathematics and Statistics, University of São Paulo, São Paulo, Brazil
| | - David E Sosnovik
- Athinoula A. Martinos Center For Biomedical Imaging, Boston, MA, USA
- Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, USA
- Athinoula A. Martinos Center For Biomedical Imaging, 149 13th Street, Charlestown, MA, 02129, USA
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Zhang C, Cheng YJ, Chen J, Wickline S, Wang LV. Label-free photoacoustic microscopy of myocardial sheet architecture. J Biomed Opt 2012; 17:060506. [PMID: 22734729 PMCID: PMC3379726 DOI: 10.1117/1.jbo.17.6.060506] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 05/03/2012] [Accepted: 05/08/2012] [Indexed: 05/04/2023]
Abstract
Cardiac myofibers are organized into sheet architectures, which contribute to up to 40% of the heart wall thickening for ejection of blood for circulation. It is important to delineate the sheet architecture for a better understanding of cardiac mechanisms. However, current sheet imaging technologies are limited by fixation-induced dehydration/deformation and low spatial resolution. Here we implemented high-resolution label-free photoacoustic microscopy (PAM) of the myocardial sheet architecture. With high endogenous optical-absorption contrast originating mainly from cytochrome, myoglobin, and melanin, PAM can image the unfixed, unstained and unsliced heart without introducing deformation artifacts. A fresh blood-free mouse heart was imaged by PAM ex vivo. The three-dimensional branching sheets were clearly identified within 150 [micro sign]m depth. Various morphological parameters were derived from the PAM image. The sheet thickness (80 ± 10 μm) and the cleavage height (11 ± 1 μm) were derived from an undehydrated heart for the first time. Therefore, PAM has the potential for the functional imaging of sheet architecture in ex vivo perfused and viable hearts.
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Affiliation(s)
- Chi Zhang
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130
| | - Ya-Jian Cheng
- Washington University School of Medicine, Cardiovascular Division, Campus Box 8215, 4320 Forest Park Avenue, St. Louis, Missouri 63108
| | - Junjie Chen
- Washington University School of Medicine, Cardiovascular Division, Campus Box 8215, 4320 Forest Park Avenue, St. Louis, Missouri 63108
| | - Samuel Wickline
- Washington University School of Medicine, Cardiovascular Division, Campus Box 8215, 4320 Forest Park Avenue, St. Louis, Missouri 63108
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130
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Creus KK, De Paepe B, Weis J, De Bleecker JL. The multifaceted character of lymphotoxin β in inflammatory myopathies and muscular dystrophies. Neuromuscul Disord 2012; 22:712-9. [PMID: 22652080 DOI: 10.1016/j.nmd.2012.04.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 04/22/2012] [Accepted: 04/30/2012] [Indexed: 11/18/2022]
Abstract
Lymphotoxin beta (LTβ) regulates some inflammatory mechanisms that could be operative in idiopathic inflammatory myopathies (IM). We studied LTβ and LTβR in inflammatory myopathies, normal and disease controls with immunohistochemistry, Western blotting and in situ hybridisation. LTβ occurs in myonuclei of normal controls, implying its role in normal muscle physiology. LTβ is strongly upregulated in regenerating muscle fibres in all myopathies, but not in denervated myofibres. Normal-appearing myofibres in inflammatory myopathies and muscular dystrophies express LTβ possibly reflecting early myofibre damage, representing a hitherto undescribed pathologic hallmark. Furthermore, we visualised LTβ in several inflammatory cell types in inflammatory myopathies, suggesting its involvement in the different inflammatory mechanisms underlying inflammatory myopathy subgroups.
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Affiliation(s)
- Kim K Creus
- Laboratory for Neuropathology, Department of Neurology, Ghent University Hospital, Ghent, Belgium
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Berg KT, Hunter DG, Bothun ED, Antunes-Foschini R, McLoon LK. Extraocular muscles in patients with infantile nystagmus: adaptations at the effector level. Arch Ophthalmol 2012; 130:343-9. [PMID: 22411664 PMCID: PMC3759680 DOI: 10.1001/archophthalmol.2011.381] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To test the hypothesis that the extraocular muscles (EOMs) of patients with infantile nystagmus have muscular and innervational adaptations that may have a role in the involuntary oscillations of the eyes. METHODS Specimens of EOMs from 10 patients with infantile nystagmus and postmortem specimens from 10 control subjects were prepared for histologic examination. The following variables were quantified: mean myofiber cross-sectional area, myofiber central nucleation, myelinated nerve density, nerve fiber density, and neuromuscular junction density. RESULTS In contrast to control EOMs, infantile nystagmus EOMs had significantly more centrally nucleated myofibers, consistent with cycles of degeneration and regeneration. The EOMs of patients with nystagmus also had a greater degree of heterogeneity in myofiber size than did those of controls, with no difference in mean myofiber cross-sectional area. Mean myelinated nerve density, nerve fiber density, and neuromuscular junction density were also significantly decreased in infantile nystagmus EOMs. CONCLUSIONS The EOMs of patients with infantile nystagmus displayed a distinct hypoinnervated phenotype. This represents the first quantification of changes in central nucleation and myofiber size heterogeneity, as well as decreased myelinated nerve, nerve fiber, and neuromuscular junction density. These results suggest that deficits in motor innervation are a potential basis for the primary loss of motor control. CLINICAL RELEVANCE Improved understanding of the etiology of nystagmus may direct future diagnostic and treatment strategies.
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Affiliation(s)
- Kathleen T Berg
- Department of Ophthalmology, University of Minnesota, Minneapolis, MN 55455, USA
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Wrede A, Margraf NG, Goebel HH, Deuschl G, Schulz-Schaeffer WJ. Myofibrillar disorganization characterizes myopathy of camptocormia in Parkinson's disease. Acta Neuropathol 2012; 123:419-32. [PMID: 22160321 PMCID: PMC3282910 DOI: 10.1007/s00401-011-0927-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 11/26/2011] [Accepted: 12/02/2011] [Indexed: 10/29/2022]
Abstract
Camptocormia is a highly disabling syndrome that occurs in various diseases but is particularly associated with Parkinson's disease (PD). Although first described nearly 200 years ago, the morphological changes associated with camptocormia are still under debate and the pathophysiology is unknown. We analyzed paraspinal muscle biopsies of 14 PD patients with camptocormia and compared the findings to sex-matched postmortem controls of comparable age to exclude biopsy site-specific changes. Camptocormia in PD showed a consistent lesion pattern composed of myopathic changes with type-1 fiber hypertrophy, loss of type-2 fibers, loss of oxidative enzyme activity, and acid phosphatase reactivity of lesions. Ultrastructurally, myofibrillar disorganization and Z-band streaming up to electron-dense patches/plaques were seen in the lesions. No aberrant protein aggregation, signs of myositis or mitochondriopathy were found, but the mitochondrial content of paraspinal muscles in patients and controls was markedly higher than known from limb biopsies. Additionally, we were able to demonstrate a link between the severity of the clinical syndrome and the degree of the myopathic changes. Because of the consistent lesion pattern, we propose criteria for the diagnosis of camptocormia in PD from muscle biopsies. The morphological changes show obvious parallels to the muscle pathology of experimental tenotomy reported in the 1970s, which depend on an intact innervation and do not occur after interruption of the myotactic reflexes. A dysregulation of the proprioception could be part of the pathogenesis of camptocormia in Parkinson's disease, particularly in view of the clinical symptoms of rigidity and loss of muscle strength.
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Affiliation(s)
- Arne Wrede
- Prion and Dementia Research Unit, Institute of Neuropathology, Medical University Center Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Nils G. Margraf
- Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Hans H. Goebel
- Institute of Neuropathology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Günther Deuschl
- Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Walter J. Schulz-Schaeffer
- Prion and Dementia Research Unit, Institute of Neuropathology, Medical University Center Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
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Jonkers RAM, Dirks ML, Nabuurs CIHC, De Feyter HM, Praet SFE, Nicolay K, van Loon LJC, Prompers JJ. Myofibrillar distribution of succinate dehydrogenase activity and lipid stores differs in skeletal muscle tissue of paraplegic subjects. Am J Physiol Endocrinol Metab 2012; 302:E365-73. [PMID: 22068603 DOI: 10.1152/ajpendo.00270.2011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Lack of physical activity has been related to an increased risk of developing insulin resistance. This study aimed to assess the impact of chronic muscle deconditioning on whole body insulin sensitivity, muscle oxidative capacity, and intramyocellular lipid (IMCL) content in subjects with paraplegia. Nine subjects with paraplegia and nine able-bodied, lean controls were recruited. An oral glucose tolerance test was performed to assess whole body insulin sensitivity. IMCL content was determined both in vivo and in vitro using (1)H-magnetic resonance spectroscopy and fluorescence microscopy, respectively. Muscle biopsy samples were stained for succinate dehydrogenase (SDH) activity to measure muscle fiber oxidative capacity. Subcellular distributions of IMCL and SDH activity were determined by defining subsarcolemmal and intermyofibrillar areas on histological samples. SDH activity was 57 ± 14% lower in muscle fibers derived from subjects with paraplegia when compared with controls (P < 0.05), but IMCL content and whole body insulin sensitivity did not differ between groups. In muscle fibers taken from controls, both SDH activity and IMCL content were higher in the subsarcolemmal region than in the intermyofibrillar area. This typical subcellular SDH and IMCL distribution pattern was lost in muscle fibers collected from subjects with paraplegia and had changed toward a more uniform distribution. In conclusion, the lower metabolic demand in deconditioned muscle of subjects with paraplegia results in a significant decline in muscle fiber oxidative capacity and is accompanied by changes in the subcellular distribution patterns of SDH activity and IMCL. However, loss of muscle activity due to paraplegia is not associated with substantial lipid accumulation in skeletal muscle tissue.
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Affiliation(s)
- Richard A M Jonkers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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Qiu X, Zheng H, Chen S, Chen D, Chen J, Wang W, Xia S. [The influence of denervation on myofiber morphology of the adductor and abductor in patients with recurrent laryngeal nerve paralysis]. Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2011; 25:1125-1130. [PMID: 22390035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
OBJECTIVE To investigate the influence of denervation on myofiber morphology of the adductor and the abductor in patients with recurrent laryngeal nerve (RLN) paralysis and to provide experimental evidence for the clinical feasibility of RLN repair. METHOD Adductor muscles were acquired from the lateral cricoarytenoid muscle (LCAM) and abductor muscles from the posterior cricoarytenoid muscle(PCAM). Normal human PCAM and LCAM are treated as control group (n = 7). Thirty-eight cases of PCAM with damaged RLN were divided into five groups according to the duration of their RLN damage: 0.5-1 year (7 cases), > 1-2 years (10 cases), > 2-3 years (8 cases), > 3-6 years (8 cases) and > 6 years (5 cases); twenty-nine cases of LCAM were also divided into five groups: 0.5-1 year (7 cases), > 1-2 years (6 cases); > 2-3 years (6 cases), > 3-6 years (6 cases) and > 6 years group(4 cases). They were all stained with HE and Masson three-color staining, the fiber cross-sectional area of muscle tissue and collagen connective tissue were quantitative analyzed. The changes of myofiber morphology of adductor and abductor muscles after the loss of the RLN were analyzed with image analysis system. RESULT The transverse areas of myofibers gradually decreased and those of collagen fibers gradually increased with the prolongation of denervation. (1) Difference between the denervated groups of LCAM of 0.5-1 year, > 1-2 years and > 2-3 years groups were not significant (P > 0.05). Fiber cross-sectional area of > 3-6 years group decreased most obviously with significantly difference compared with > 2-3 years group (P < 0.05); (2) There were obvious difference between the control group, 0.5-1 year group, > 1-2 years group, > 2-3 years group and > 3-6 years of PCAM(P < 0.05); (3) There was no significant difference between the group of > 3-6 years and > 6 years of two kinds of laryngeal intrinsic muscle (P > 0.05); (4) Fiber cross-sectional area of each group of the LCAM after 1 year denervation were significantly greater than that of the PCAM under same conditions (P < 0.05). CONCLUSION The influence of denervation on myofiber morphology following denervation is different between the abductor and adductor owing to the different fiber type composition and functional properties. The rate of muscle atrophy of the adductor is slower than that of the abductor. To restore the structure and function of denervated laryngeal muscles better, the recurrent laryngeal nerve injury repair surgery for PCA muscle function recovery should be carried out within 1 year after denervation while the surgery for LCA muscle function recovery should be carried out within 3 years after denervation.
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Affiliation(s)
- Xiaoxia Qiu
- Department of Otolaryngology-Head and Neck Surgery, Changhai Hospital, the Second Military Medical University, Shanghai, 200433, China
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Abstract
Homer proteins are a family of multifaceted scaffolding proteins that participate in the organization of signaling complexes at the post-synaptic density and in a variety of tissues including striated muscle. Homer isoforms form multimers via their C-terminal coiled coil domains, which allows for the formation of a polymeric network in combination with other scaffolding proteins. We hypothesized that the ability of Homer isoforms to serve as scaffolds would be influenced by oxidative stress. We have found by standard SDS-PAGE of lysates from adult mouse skeletal muscle exposed to air oxidation that Homer migrates as both a dimer and monomer in the absence of reducing agents and solely as a monomer in the presence of a reducing agent, suggesting that Homer dimers exposed to oxidation could be modified by the presence of an inter-molecular disulfide bond. Analysis of the peptide sequence of Homer 1b revealed the presence of only two cysteine residues located adjacent to the C-terminal coiled-coil domain. HEK 293 cells were transfected with wild-type and cysteine mutant forms of Homer 1b and exposed to oxidative stress by addition of menadione, which resulted in the formation of disulfide bonds except in the double mutant (C246G, C365G). Exposure of myofibers from adult mice to oxidative stress resulted in decreased solubility of endogenous Homer isoforms. This change in solubility was dependent on disulfide bond formation. In vitro binding assays revealed that cross-linking of Homer dimers enhanced the ability of Homer 1b to bind Drebrin, a known interacting partner. Our results show that oxidative stress results in disulfide cross-linking of Homer isoforms and loss of solubility of Homer scaffolds. This suggests that disulfide cross-linking of a Homer polymeric network may contribute to the pathophysiology seen in neurodegenerative diseases and myopathies characterized by oxidative stress.
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Affiliation(s)
- Igor Nepliouev
- Ion Channel Research Unit and Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Zhu-Shan Zhang
- Ion Channel Research Unit and Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Jonathan A. Stiber
- Ion Channel Research Unit and Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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Abstract
Although androgen receptor (AR) within myocytes is thought to mediate many of the effects of testosterone and other androgens on skeletal muscle, little is known about the functions of AR within these cells. We, therefore, studied the ultrastructure of skeletal muscle of HSA-AR transgenic (Tg) mice that overexpress AR selectively in myocytes and exhibit neuromuscular atrophy. We examined male HSA-AR mice from two different founding lines: L78 (lower copy number and less severe phenotype) and L141 (higher copy number and more severe phenotype) and compared these to wild-type (Wt) brothers. We also examined testosterone-treated female mice from these two lines and compared them both to their Wt sisters and to vehicle-treated controls. Ultrastructural examination of extensor digitorum longus sections using transmission electron microscopy revealed remarkably disorganized myofibrils in male Tg and testosterone-treated female Tg mice. Quantification of ultrastructural pathology indicated reduced myofibril width, hypertrophic and hyperplastic intermyofibrillar mitochondria, and pronounced glycogen accumulation in HSA-AR males of both lines. Reduced myofibrillar width and increases in mitochondrial number, size, and volume density were also observed in testosterone-treated HSA-AR females, although glycogen accumulation was not observed. Structural abnormalities in mitochondria were also associated with increases in electron transport chain activity and systemic resting metabolic rate, indicative of hypermetabolism. We find that overexpression of AR in myocytes of HSA-AR mice results in alterations in myofibrils, mitochondria, and glycogen. Alterations in myofibrils and mitochondria appear to result from acute actions of testosterone, whereas those on glycogen do not. Pathology of myofibrils and/or mitochondria may, therefore, mediate in part the neuromuscular atrophy observed in HSA-AR mice.
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MESH Headings
- Animals
- Atrophy
- Basal Metabolism
- Electron Transport Chain Complex Proteins/metabolism
- Female
- Gene Dosage
- Gene Expression
- Glycogen/metabolism
- Male
- Mice
- Mice, Transgenic
- Microscopy, Electron, Transmission
- Mitochondria, Muscle/drug effects
- Mitochondria, Muscle/metabolism
- Mitochondria, Muscle/pathology
- Muscle Proteins/biosynthesis
- Muscle Proteins/genetics
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Myofibrils/drug effects
- Myofibrils/pathology
- Neuromuscular Diseases/chemically induced
- Neuromuscular Diseases/metabolism
- Neuromuscular Diseases/pathology
- Receptors, Androgen/biosynthesis
- Receptors, Androgen/genetics
- Sex Factors
- Testosterone/toxicity
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Affiliation(s)
- Mutaz Musa
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada M5S 3G3
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Laky D, Parascan L, Cândea V. Atrial structural remodeling in patients with atrial chronic fibrillations and in animal models. Rom J Morphol Embryol 2011; 52:95-98. [PMID: 21424038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Arrhythmia's atrium fibrillation (AF) is the most often met in clinical setting and it is associated with an increased in mortality risk. For profound the structural changes in chronic AF, we are studied the morphological changes of atrium biopsies to be effected at 175 patients. With sustained AF malformative and valvular acquired cardiac diseases operated under extracorporeal circulation. Similar studies we are effected to 11 dogs with partial coronary obstructions to a made periodical EKG investigations. The morphological changes mainly concern accommodation (dedifferentiation) of cardiomyocytes (particularly at experimental model) and mal-accommodation (degeneration of cells with fibrosis replacement features) particularly in acquired valvular diseases. These changes were often interfered. Over study, maintain the hypothesis that the structural changes to be an accommodation more than degenerative response to AF.
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Affiliation(s)
- D Laky
- "Victor Babeş" National Institute, Bucharest, Romania
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Smuder AJ, Kavazis AN, Hudson MB, Nelson WB, Powers SK. Oxidation enhances myofibrillar protein degradation via calpain and caspase-3. Free Radic Biol Med 2010; 49:1152-60. [PMID: 20600829 PMCID: PMC2930052 DOI: 10.1016/j.freeradbiomed.2010.06.025] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 05/10/2010] [Accepted: 06/21/2010] [Indexed: 01/12/2023]
Abstract
Oxidative stress has been linked to accelerated rates of proteolysis and muscle fiber atrophy during periods of prolonged skeletal muscle inactivity. However, the mechanism(s) that links oxidative stress to muscle protein degradation remains unclear. A potential connection between oxidants and accelerated proteolysis in muscle fibers is that oxidative modification of myofibrillar proteins may enhance their susceptibility to proteolytic processing. In this regard, it is established that protein oxidation promotes protein recognition and degradation by the 20S proteasome. However, it is unknown whether oxidation of myofibrillar proteins increases their recognition and degradation by calpains and/or caspase-3. Therefore, we tested the hypothesis that oxidative modification of myofibrillar proteins increases their susceptibility to degradation by both calpains and caspase-3. To test this postulate, myofibrillar proteins were isolated from rat skeletal muscle and exposed to in vitro oxidation to produce varying levels of protein modification. Modified proteins were then independently incubated with active calpain I, calpain II, or caspase-3 and the rates of protein degradation were assessed via peptide mapping. Our results reveal that increased protein oxidation results in a stepwise escalation in the degradation of myofibrillar proteins by calpain I, calpain II, and caspase-3. These findings provide a mechanistic link connecting oxidative stress with accelerated myofibrillar proteolysis during disuse muscle atrophy.
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Affiliation(s)
- Ashley J Smuder
- Center for Exercise Science, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA
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50
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Kane DA, Anderson EJ, Price JW, Woodlief TL, Lin CT, Bikman BT, Cortright RN, Neufer PD. Metformin selectively attenuates mitochondrial H2O2 emission without affecting respiratory capacity in skeletal muscle of obese rats. Free Radic Biol Med 2010; 49:1082-7. [PMID: 20600832 PMCID: PMC2921476 DOI: 10.1016/j.freeradbiomed.2010.06.022] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 06/10/2010] [Accepted: 06/21/2010] [Indexed: 11/21/2022]
Abstract
Metformin is a widely prescribed drug for treatment of type 2 diabetes, although no cellular mechanism of action has been established. To determine whether in vivo metformin treatment alters mitochondrial function in skeletal muscle, respiratory O(2) flux and H(2)O(2) emission were measured in saponin-permeabilized myofibers from lean and obese (fa/fa) Zucker rats treated for 4 weeks with metformin. Succinate- and palmitoylcarnitine-supported respiration generated greater than twofold higher rates of H(2)O(2) emission in myofibers from untreated obese versus lean rats, indicative of an obesity-associated increased mitochondrial oxidant emitting potential. In conjunction with improved glycemic control, metformin treatment reduced H(2)O(2) emission in muscle from obese rats to rates near or below those observed in lean rats during both succinate- and palmitoylcarnitine-supported respiration. Surprisingly, metformin treatment did not affect basal or maximal rates of O(2) consumption in muscle from obese or lean rats. Ex vivo dose-response experiments revealed that metformin inhibits complex I-linked H(2)O(2) emission at a concentration approximately 2 orders of magnitude lower than that required to inhibit respiratory O(2) flux. These findings suggest that therapeutic concentrations of metformin normalize mitochondrial H(2)O(2) emission by blocking reverse electron flow without affecting forward electron flow or respiratory O(2) flux in skeletal muscle.
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MESH Headings
- Animals
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/physiopathology
- Electron Transport Complex I/metabolism
- Hydrogen Peroxide/metabolism
- Male
- Metformin/administration & dosage
- Metformin/therapeutic use
- Mitochondria, Muscle/drug effects
- Mitochondria, Muscle/metabolism
- Mitochondria, Muscle/pathology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Myofibrils/drug effects
- Myofibrils/pathology
- Obesity
- Oxygen Consumption/drug effects
- Rats
- Rats, Sprague-Dawley
- Rats, Zucker
- Respiratory Rate/drug effects
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Affiliation(s)
- Daniel A. Kane
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina
| | - Ethan J. Anderson
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Pharmacology & Toxicology, East Carolina University, Greenville, North Carolina
- Department of Cardiovascular Sciences, East Carolina University, Greenville, North Carolina
| | - Jesse W. Price
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Biology, East Carolina University, Greenville, North Carolina
| | - Tracey L. Woodlief
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina
| | - Chien-Te Lin
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina
| | - Benjamin T. Bikman
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina
| | - Ronald N. Cortright
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina
- Department of Physiology, East Carolina University, Greenville, North Carolina
| | - P. Darrell Neufer
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina
- Department of Physiology, East Carolina University, Greenville, North Carolina
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