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Sundby LJ, Southern WM, Sun J, Patrinostro X, Zhang W, Yong J, Ervasti JM. Deletion of exons 2 and 3 from Actb and cell immortalization lead to widespread, β-actin independent alterations in gene expression associated with cell cycle control. Eur J Cell Biol 2024; 103:151397. [PMID: 38387258 DOI: 10.1016/j.ejcb.2024.151397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 02/11/2024] [Accepted: 02/12/2024] [Indexed: 02/24/2024] Open
Abstract
The cytoplasmic actin proteins, β- and γ-actin, are 99% identical but thought to perform non-redundant functions. The nucleotide coding regions of cytoplasmic actin genes, Actb and Actg1, are 89% identical. Knockout (KO) of Actb by Cre-mediated deletion of first coding exons 2 and 3 in mice is embryonic lethal and fibroblasts derived from KO embryos (MEFs) fail to proliferate. In contrast, Actg1 KO MEFs display with a much milder defect in cell proliferation and Actg1 KO mice are viable, but present with increased perinatal lethality. Recent studies have identified important protein-independent functions for both Actb and Actg1 and demonstrate that deletions within the Actb nucleotide sequence, and not loss of the β-actin protein, cause the most severe phenotypes in KO mice and cells. Here, we use a multi-omics approach to better understand what drives the phenotypes of Actb KO MEFs. RNA-sequencing and mass spectrometry reveal largescale changes to the transcriptome, proteome, and phosphoproteome in cells lacking Actb but not those only lacking β-actin protein. Pathway analysis of genes and proteins differentially expressed upon Actb KO suggest widespread dysregulation of genes involved in the cell cycle that may explain the severe defect in proliferation.
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Affiliation(s)
- Lauren J Sundby
- Program in Molecular, Cellular, Developmental Biology, and Genetics, University of Minnesota, Minneapolis, MN 55455, USA
| | - William M Southern
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jiao Sun
- Department of Computer Science, University of Central Florida, Orlando, FL 32816, USA
| | - Xiaobai Patrinostro
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Wei Zhang
- Department of Computer Science, University of Central Florida, Orlando, FL 32816, USA
| | - Jeongsik Yong
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
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2
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Hoshimaru T, Nonoguchi N, Kosaka T, Furuse M, Kawabata S, Yagi R, Kurisu Y, Kashiwagi H, Kameda M, Takami T, Kataoka-Sasaki Y, Sasaki M, Honmou O, Hiramatsu R, Wanibuchi M. Actin Alpha 2, Smooth Muscle (ACTA2) Is Involved in the Migratory Potential of Malignant Gliomas, and Its Increased Expression at Recurrence Is a Significant Adverse Prognostic Factor. Brain Sci 2023; 13:1477. [PMID: 37891844 PMCID: PMC10605410 DOI: 10.3390/brainsci13101477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/17/2023] [Accepted: 10/17/2023] [Indexed: 10/29/2023] Open
Abstract
Malignant glioma is a highly invasive tumor, and elucidating the glioma invasion mechanism is essential for developing novel therapies. We aimed to highlight actin alpha 2, smooth muscle (ACTA2) as potential biomarkers of brain invasion and distant recurrence in malignant gliomas. Using the human malignant glioma cell line, U251MG, we generated ACTA2 knockdown (KD) cells treated with small interfering RNA, and the cell motility and proliferation of the ACTA2 KD group were analyzed. Furthermore, tumor samples from 12 glioma patients who underwent reoperation at the time of tumor recurrence were utilized to measure ACTA2 expression in the tumors before and after recurrence. Thereafter, we examined how ACTA2 expression correlates with the time to tumor recurrence and the mode of recurrence. The results showed that the ACTA2 KD group demonstrated a decline in the mean motion distance and proliferative capacity compared to the control group. In the clinical glioma samples, ACTA2 expression was remarkably increased in recurrent samples compared to the primary samples from the same patients, and the higher the change in ACTCA2 expression from the start to relapse, the shorter the progression-free survival. In conclusion, ACTA2 may be involved in distant recurrence in clinical gliomas.
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Affiliation(s)
- Takumi Hoshimaru
- Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Naosuke Nonoguchi
- Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Takuya Kosaka
- Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Motomasa Furuse
- Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Shinji Kawabata
- Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Ryokichi Yagi
- Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Yoshitaka Kurisu
- Department of Pathology, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Hideki Kashiwagi
- Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Masahiro Kameda
- Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Toshihiro Takami
- Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Yuko Kataoka-Sasaki
- Department of Neural Regenerative Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Hokkaido 060-8556, Japan
| | - Masanori Sasaki
- Department of Neural Regenerative Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Hokkaido 060-8556, Japan
| | - Osamu Honmou
- Department of Neural Regenerative Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Hokkaido 060-8556, Japan
| | - Ryo Hiramatsu
- Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Masahiko Wanibuchi
- Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
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3
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Bai Y, Zhao F, Wu T, Chen F, Pang X. Actin polymerization and depolymerization in developing vertebrates. Front Physiol 2023; 14:1213668. [PMID: 37745245 PMCID: PMC10515290 DOI: 10.3389/fphys.2023.1213668] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 08/22/2023] [Indexed: 09/26/2023] Open
Abstract
Development is a complex process that occurs throughout the life cycle. F-actin, a major component of the cytoskeleton, is essential for the morphogenesis of tissues and organs during development. F-actin is formed by the polymerization of G-actin, and the dynamic balance of polymerization and depolymerization ensures proper cellular function. Disruption of this balance results in various abnormalities and defects or even embryonic lethality. Here, we reviewed recent findings on the structure of G-actin and F-actin and the polymerization of G-actin to F-actin. We also focused on the functions of actin isoforms and the underlying mechanisms of actin polymerization/depolymerization in cellular and organic morphogenesis during development. This information will extend our understanding of the role of actin polymerization in the physiologic or pathologic processes during development and may open new avenues for developing therapeutics for embryonic developmental abnormalities or tissue regeneration.
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Affiliation(s)
- Yang Bai
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Feng Zhao
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Tingting Wu
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Fangchun Chen
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Xiaoxiao Pang
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
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4
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Miyoshi T, Belyantseva IA, Kitajiri SI, Miyajima H, Nishio SY, Usami SI, Kim BJ, Choi BY, Omori K, Shroff H, Friedman TB. Human deafness-associated variants alter the dynamics of key molecules in hair cell stereocilia F-actin cores. Hum Genet 2022; 141:363-382. [PMID: 34232383 PMCID: PMC11351816 DOI: 10.1007/s00439-021-02304-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 06/15/2021] [Indexed: 12/16/2022]
Abstract
Stereocilia protrude up to 100 µm from the apical surface of vertebrate inner ear hair cells and are packed with cross-linked filamentous actin (F-actin). They function as mechanical switches to convert sound vibration into electrochemical neuronal signals transmitted to the brain. Several genes encode molecular components of stereocilia including actin monomers, actin regulatory and bundling proteins, motor proteins and the proteins of the mechanotransduction complex. A stereocilium F-actin core is a dynamic system, which is continuously being remodeled while maintaining an outwardly stable architecture under the regulation of F-actin barbed-end cappers, severing proteins and crosslinkers. The F-actin cores of stereocilia also provide a pathway for motor proteins to transport cargos including components of tip-link densities, scaffolding proteins and actin regulatory proteins. Deficiencies and mutations of stereocilia components that disturb this "dynamic equilibrium" in stereocilia can induce morphological changes and disrupt mechanotransduction causing sensorineural hearing loss, best studied in mouse and zebrafish models. Currently, at least 23 genes, associated with human syndromic and nonsyndromic hearing loss, encode proteins involved in the development and maintenance of stereocilia F-actin cores. However, it is challenging to predict how variants associated with sensorineural hearing loss segregating in families affect protein function. Here, we review the functions of several molecular components of stereocilia F-actin cores and provide new data from our experimental approach to directly evaluate the pathogenicity and functional impact of reported and novel variants of DIAPH1 in autosomal-dominant DFNA1 hearing loss using single-molecule fluorescence microscopy.
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Affiliation(s)
- Takushi Miyoshi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Porter Neuroscience Research Center, Room 1F-143A, Bethesda, MD, 20892, USA.
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan.
| | - Inna A Belyantseva
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Porter Neuroscience Research Center, Room 1F-143A, Bethesda, MD, 20892, USA
| | - Shin-Ichiro Kitajiri
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, 390-8621, Matsumoto, Japan
| | - Hiroki Miyajima
- Department of Otolaryngology, Shinshu University School of Medicine, Matsumoto, 390-8621, Japan
- Department of Otolaryngology, Aizawa Hospital, Matsumoto, 390-8510, Japan
| | - Shin-Ya Nishio
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, 390-8621, Matsumoto, Japan
| | - Shin-Ichi Usami
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, 390-8621, Matsumoto, Japan
| | - Bong Jik Kim
- Department of Otolaryngology-Head and Neck Surgery, Chungnam National University College of Medicine, Chungnam National University Sejong Hospital, Sejong, 30099, South Korea
- Brain Research Institute, Chungnam National University College of Medicine, Daejeon, 35015, South Korea
| | - Byung Yoon Choi
- Department of Otorhinolaryngology, Seoul National University Bundang Hospital, Seongnam, 13620, South Korea
| | - Koichi Omori
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Hari Shroff
- Laboratory of High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Porter Neuroscience Research Center, Room 1F-143A, Bethesda, MD, 20892, USA
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5
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The Oxidative Balance Orchestrates the Main Keystones of the Functional Activity of Cardiomyocytes. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:7714542. [PMID: 35047109 PMCID: PMC8763515 DOI: 10.1155/2022/7714542] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 11/03/2021] [Accepted: 12/15/2021] [Indexed: 12/11/2022]
Abstract
This review is aimed at providing an overview of the key hallmarks of cardiomyocytes in physiological and pathological conditions. The main feature of cardiac tissue is the force generation through contraction. This process requires a conspicuous energy demand and therefore an active metabolism. The cardiac tissue is rich of mitochondria, the powerhouses in cells. These organelles, producing ATP, are also the main sources of ROS whose altered handling can cause their accumulation and therefore triggers detrimental effects on mitochondria themselves and other cell components thus leading to apoptosis and cardiac diseases. This review highlights the metabolic aspects of cardiomyocytes and wanders through the main systems of these cells: (a) the unique structural organization (such as different protein complexes represented by contractile, regulatory, and structural proteins); (b) the homeostasis of intracellular Ca2+ that represents a crucial ion for cardiac functions and E-C coupling; and (c) the balance of Zn2+, an ion with a crucial impact on the cardiovascular system. Although each system seems to be independent and finely controlled, the contractile proteins, intracellular Ca2+ homeostasis, and intracellular Zn2+ signals are strongly linked to each other by the intracellular ROS management in a fascinating way to form a "functional tetrad" which ensures the proper functioning of the myocardium. Nevertheless, if ROS balance is not properly handled, one or more of these components could be altered resulting in deleterious effects leading to an unbalance of this "tetrad" and promoting cardiovascular diseases. In conclusion, this "functional tetrad" is proposed as a complex network that communicates continuously in the cardiomyocytes and can drive the switch from physiological to pathological conditions in the heart.
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Suresh R, Diaz RJ. The remodelling of actin composition as a hallmark of cancer. Transl Oncol 2021; 14:101051. [PMID: 33761369 PMCID: PMC8008238 DOI: 10.1016/j.tranon.2021.101051] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/01/2021] [Accepted: 02/17/2021] [Indexed: 02/06/2023] Open
Abstract
Actin is a key structural protein that makes up the cytoskeleton of cells, and plays a role in functions such as division, migration, and vesicle trafficking. It comprises six different cell-type specific isoforms: ACTA1, ACTA2, ACTB, ACTC1, ACTG1, and ACTG2. Abnormal actin isoform expression has been reported in many cancers, which led us to hypothesize that it may serve as an early biomarker of cancer. We show an overview of the different actin isoforms and highlight mechanisms by which they may contribute to tumorigenicity. Furthermore, we suggest how the aberrant expression of actin subunits can confer cells with greater proliferation ability, increased migratory capability, and chemoresistance through incorporation into the normal cellular F-actin network and altered actin binding protein interaction. Studying this fundamental change that takes place within cancer cells can further our understanding of neoplastic transformation in multiple tissue types, which can ultimately aid in the early-detection, diagnosis and treatment of cancer.
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Affiliation(s)
- Rahul Suresh
- Montreal Neurological Institute, Integrated Program in Neuroscience, McGill University, Montreal, Canada
| | - Roberto J Diaz
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, Faculty of Medicine, McGill University, Montreal, Canada.
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Sadler KJ, Gatta PAD, Naim T, Wallace MA, Lee A, Zaw T, Lindsay A, Chung RS, Bello L, Pegoraro E, Lamon S, Lynch GS, Russell AP. Striated muscle activator of Rho signalling (STARS) overexpression in the mdx mouse enhances muscle functional capacity and regulates the actin cytoskeleton and oxidative phosphorylation pathways. Exp Physiol 2021; 106:1597-1611. [PMID: 33963617 DOI: 10.1113/ep089253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 05/04/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Striated muscle activator of rho signalling (STARS) is an actin-binding protein that regulates transcriptional pathways controlling muscle function, growth and myogenesis, processes that are impaired in dystrophic muscle: what is the regulation of the STARS pathway in Duchenne muscular dystrophy (DMD)? What is the main finding and its importance? Members of the STARS signalling pathway are reduced in the quadriceps of patients with DMD and in mouse models of muscular dystrophy. Overexpression of STARS in the dystrophic deficient mdx mouse model increased maximal isometric specific force and upregulated members of the actin cytoskeleton and oxidative phosphorylation pathways. Regulating STARS may be a therapeutic approach to enhance muscle health. ABSTRACT Duchenne muscular dystrophy (DMD) is characterised by impaired cytoskeleton organisation, cytosolic calcium handling, oxidative stress and mitochondrial dysfunction. This results in progressive muscle damage, wasting and weakness and premature death. The striated muscle activator of rho signalling (STARS) is an actin-binding protein that activates the myocardin-related transcription factor-A (MRTFA)/serum response factor (SRF) transcriptional pathway, a pathway regulating cytoskeletal structure and muscle function, growth and repair. We investigated the regulation of the STARS pathway in the quadriceps muscle from patients with DMD and in the tibialis anterior (TA) muscle from the dystrophin-deficient mdx and dko (utrophin and dystrophin null) mice. Protein levels of STARS, SRF and RHOA were reduced in patients with DMD. STARS, SRF and MRTFA mRNA levels were also decreased in DMD muscle, while Stars mRNA levels were decreased in the mdx mice and Srf and Mrtfa mRNAs decreased in the dko mice. Overexpressing human STARS (hSTARS) in the TA muscles of mdx mice increased maximal isometric specific force by 13% (P < 0.05). This was not associated with changes in muscle mass, fibre cross-sectional area, fibre type, centralised nuclei or collagen deposition. Proteomics screening followed by pathway enrichment analysis identified that hSTARS overexpression resulted in 31 upregulated and 22 downregulated proteins belonging to the actin cytoskeleton and oxidative phosphorylation pathways. These pathways are impaired in dystrophic muscle and regulate processes that are vital for muscle function. Increasing the STARS protein in dystrophic muscle improves muscle force production, potentially via synergistic regulation of cytoskeletal structure and energy production.
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Affiliation(s)
- Kate J Sadler
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Paul A Della Gatta
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Timur Naim
- Department of Physiology, Centre for Muscle Research, University of Melbourne, Parkville, Victoria, Australia
| | - Marita A Wallace
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Albert Lee
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Centre for Motor Neuron Disease Research, Macquarie University, Sydney, New South Wales, Australia
| | - Thiri Zaw
- Australian Proteome Analysis Facility, Macquarie University, Sydney, New South Wales, Australia
| | - Angus Lindsay
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Roger S Chung
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Centre for Motor Neuron Disease Research, Macquarie University, Sydney, New South Wales, Australia
| | - Luca Bello
- Department of Neurosciences, ERN Neuromuscular Center, University of Padua, Padua, Italy
| | - Elena Pegoraro
- Department of Neurosciences, ERN Neuromuscular Center, University of Padua, Padua, Italy
| | - Séverine Lamon
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Gordon S Lynch
- Department of Physiology, Centre for Muscle Research, University of Melbourne, Parkville, Victoria, Australia
| | - Aaron P Russell
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
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8
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Hashmi SK, Barka V, Yang C, Schneider S, Svitkina TM, Heuckeroth RO. Pseudo-obstruction-inducing ACTG2R257C alters actin organization and function. JCI Insight 2020; 5:140604. [PMID: 32814715 PMCID: PMC7455133 DOI: 10.1172/jci.insight.140604] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/15/2020] [Indexed: 12/14/2022] Open
Abstract
Actin γ 2, smooth muscle (ACTG2) R257C mutation is the most common genetic cause of visceral myopathy. Individuals with ACTG2 mutations endure prolonged hospitalizations and surgical interventions, become dependent on intravenous nutrition and bladder catheterization, and often die in childhood. Currently, we understand little about how ACTG2 mutations cause disease, and there are no mechanism-based treatments. Our goal was to characterize the effects of ACTG2R257C on actin organization and function in visceral smooth muscle cells. We overexpressed ACTG2WT or ACTG2R257C in primary human intestinal smooth muscle cells (HISMCs) and performed detailed quantitative analyses to examine effects of ACTG2R257C on (a) actin filament formation and subcellular localization, (b) actin-dependent HISMC functions, and (c) smooth muscle contractile gene expression. ACTG2R257C resulted in 41% fewer, 13% thinner, 33% shorter, and 40% less branched ACTG2 filament bundles compared with ACTG2WT. Curiously, total F-actin probed by phalloidin and a pan-actin antibody was unchanged between ACTG2WT- and ACTG2R257C-expressing HISMCs, as was ultrastructural F-actin organization. ACTG2R257C-expressing HISMCs contracted collagen gels similar to ACTG2WT-expressing HISMCs but spread 21% more and were 11% more migratory. In conclusion, ACTG2R257C profoundly affects ACTG2 filament bundle structure, without altering global actin cytoskeleton in HISMCs.
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Affiliation(s)
- Sohaib Khalid Hashmi
- Department of Pediatrics, Children's Hospital of Philadelphia Research Institute, and Perelman School of Medicine at the University of Pennsylvania, Abramson Research Center, Philadelphia, Pennsylvania, USA.,Department of Bioengineering, University of Pennsylvania School of Engineering and Applied Science, Philadelphia, Pennsylvania, USA
| | - Vasia Barka
- Department of Pediatrics, Children's Hospital of Philadelphia Research Institute, and Perelman School of Medicine at the University of Pennsylvania, Abramson Research Center, Philadelphia, Pennsylvania, USA
| | - Changsong Yang
- Department of Biology, University of Pennsylvania School of Arts and Sciences, Philadelphia, Pennsylvania, USA
| | - Sabine Schneider
- Department of Pediatrics, Children's Hospital of Philadelphia Research Institute, and Perelman School of Medicine at the University of Pennsylvania, Abramson Research Center, Philadelphia, Pennsylvania, USA
| | - Tatyana M Svitkina
- Department of Biology, University of Pennsylvania School of Arts and Sciences, Philadelphia, Pennsylvania, USA
| | - Robert O Heuckeroth
- Department of Pediatrics, Children's Hospital of Philadelphia Research Institute, and Perelman School of Medicine at the University of Pennsylvania, Abramson Research Center, Philadelphia, Pennsylvania, USA
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9
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Egge N, Arneaud SLB, Wales P, Mihelakis M, McClendon J, Fonseca RS, Savelle C, Gonzalez I, Ghorashi A, Yadavalli S, Lehman WJ, Mirzaei H, Douglas PM. Age-Onset Phosphorylation of a Minor Actin Variant Promotes Intestinal Barrier Dysfunction. Dev Cell 2020; 51:587-601.e7. [PMID: 31794717 DOI: 10.1016/j.devcel.2019.11.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 09/17/2019] [Accepted: 11/03/2019] [Indexed: 12/28/2022]
Abstract
Age-associated decay of intercellular interactions impairs the cells' capacity to tightly associate within tissues and form a functional barrier. This barrier dysfunction compromises organ physiology and contributes to systemic failure. The actin cytoskeleton represents a key determinant in maintaining tissue architecture. Yet, it is unclear how age disrupts the actin cytoskeleton and how this, in turn, promotes mortality. Here, we show that an uncharacterized phosphorylation of a low-abundant actin variant, ACT-5, compromises integrity of the C. elegans intestinal barrier and accelerates pathogenesis. Age-related loss of the heat-shock transcription factor, HSF-1, disrupts the JUN kinase and protein phosphatase I equilibrium which increases ACT-5 phosphorylation within its troponin binding site. Phosphorylated ACT-5 accelerates decay of the intestinal subapical terminal web and impairs its interactions with cell junctions. This compromises barrier integrity, promotes pathogenesis, and drives mortality. Thus, we provide the molecular mechanism by which age-associated loss of specialized actin networks impacts tissue integrity.
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Affiliation(s)
- Nathan Egge
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Medical Scientist Training Program, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sonja L B Arneaud
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Pauline Wales
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Melina Mihelakis
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jacob McClendon
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Rene Solano Fonseca
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Charles Savelle
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ian Gonzalez
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Atossa Ghorashi
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | | | - William J Lehman
- Department of Structural Biology, Boston University, Boston, MA 02118, USA
| | - Hamid Mirzaei
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Peter M Douglas
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Hamon Center for Regenerative Science and Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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10
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Liu X, Lu Y, Lian Y, Chen Z, Xia J, Meng L, Qi Z. Macrophage Depletion Improves Chronic Rejection in Rats With Allograft Heart Transplantation. Transplant Proc 2020; 52:992-1000. [PMID: 32122662 DOI: 10.1016/j.transproceed.2019.12.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 10/11/2019] [Accepted: 12/15/2019] [Indexed: 10/24/2022]
Abstract
BACKGROUND Macrophages may be important in chronic rejection after organ transplantation. This study aimed to investigate the possibility of depleting macrophages for a certain amount of time to alleviate chronic rejection in a heart transplant model of Fischer to Lewis rats. METHODS Clodronate liposome was injected abdominally to deplete macrophages for 2 time frames. The expression levels of ectodysplasin 1, arginase 1 (Arg1), chitinase-like lectin (Ym1), interferon gamma, tumor necrosis factor α (TNF-α), smooth muscle α-actin (α-SMA), monocyte chemoattractant protein 1 (MCP-1), and interleukin 10 (IL-10) were detected. RESULTS 1. The expression levels of α-SMA, interferon gamma, TNF-α, and MCP-1 and the transformation of peripheral T cells were lower after macrophage depletion for 2 or 4 weeks. 2. The expression levels of α-SMA, TNF-α, and MCP-1 and the transformation of peripheral T cells were even lower after 4 weeks compared with 2 weeks, except for interferon gamma. 3. A higher level of expression of Arg1 and Ym1 after macrophage depletion for 2 weeks was observed. 4. A higher level of expression of IL-10 after macrophage depletion for 2 weeks, but not 4 weeks, was also observed. CONCLUSIONS Macrophage clearance after heart transplantation alleviated chronic rejection probably via M2 polarization of regenerated macrophages, reduced T-lymphocyte proliferation, and changed the expression levels of interferon gamma, TNF-α, MCP-1, and IL-10.
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Affiliation(s)
- X Liu
- Organ Transplantation Institute, Medical College, Xiamen University, Xiamen, China; Department of General Surgery, Affiliated Xiang'an Hospital of Xiamen University, Xiamen, China.
| | - Y Lu
- Department of General Surgery, Affiliated Zhongshan Hospital of Xiamen University, Xiamen, China
| | - Y Lian
- Organ Transplantation Institute, Medical College, Xiamen University, Xiamen, China; Department of Thoracic Surgery, Xiamen Hospital of Traditional Chinese Medicine, Xiamen, China
| | - Z Chen
- Organ Transplantation Institute, Medical College, Xiamen University, Xiamen, China; Department of General Surgery, The Second Hospital of Xiamen City, Xiamen, China
| | - J Xia
- Organ Transplantation Institute, Medical College, Xiamen University, Xiamen, China
| | - L Meng
- Organ Transplantation Institute, Medical College, Xiamen University, Xiamen, China
| | - Z Qi
- Organ Transplantation Institute, Medical College, Xiamen University, Xiamen, China.
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11
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Congenital heart diseases: genetics, non-inherited risk factors, and signaling pathways. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2020. [DOI: 10.1186/s43042-020-0050-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Abstract
Background
Congenital heart diseases (CHDs) are the most common congenital anomalies with an estimated prevalence of 8 in 1000 live births. CHDs occur as a result of abnormal embryogenesis of the heart. Congenital heart diseases are associated with significant mortality and morbidity. The damage of the heart is irreversible due to a lack of regeneration potential, and usually, the patients may require surgical intervention. Studying the developmental biology of the heart is essential not only in understanding the mechanisms and pathogenesis of congenital heart diseases but also in providing us with insight towards developing new preventive and treatment methods.
Main body
The etiology of congenital heart diseases is still elusive. Both genetic and environmental factors have been implicated to play a role in the pathogenesis of the diseases. Recently, cardiac transcription factors, cardiac-specific genes, and signaling pathways, which are responsible for early cardiac morphogenesis have been extensively studied in both human and animal experiments but leave much to be desired. The discovery of novel genetic methods such as next generation sequencing and chromosomal microarrays have led to further study the genes, non-coding RNAs and subtle chromosomal changes, elucidating their implications to the etiology of congenital heart diseases. Studies have also implicated non-hereditary risk factors such as rubella infection, teratogens, maternal age, diabetes mellitus, and abnormal hemodynamics in causing CHDs.
These etiological factors raise questions on multifactorial etiology of CHDs. It is therefore important to endeavor in research based on finding the causes of CHDs. Finding causative factors will enable us to plan intervention strategies and mitigate the consequences associated with CHDs. This review, therefore, puts forward the genetic and non-genetic causes of congenital heart diseases. Besides, it discusses crucial signaling pathways which are involved in early cardiac morphogenesis. Consequently, we aim to consolidate our knowledge on multifactorial causes of CHDs so as to pave a way for further research regarding CHDs.
Conclusion
The multifactorial etiology of congenital heart diseases gives us a challenge to explicitly establishing specific causative factors and therefore plan intervention strategies. More well-designed studies and the use of novel genetic technologies could be the way through the discovery of etiological factors implicated in the pathogenesis of congenital heart diseases.
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12
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Angelini A, Gorey MA, Dumont F, Mougenot N, Chatzifrangkeskou M, Muchir A, Li Z, Mericskay M, Decaux JF. Cardioprotective effects of α-cardiac actin on oxidative stress in a dilated cardiomyopathy mouse model. FASEB J 2019; 34:2987-3005. [PMID: 31908029 DOI: 10.1096/fj.201902389r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 12/12/2019] [Accepted: 12/15/2019] [Indexed: 12/12/2022]
Abstract
The expression of α-cardiac actin, a major constituent of the cytoskeleton of cardiomyocytes, is dramatically decreased in a mouse model of dilated cardiomyopathy triggered by inducible cardiac-specific serum response factor (Srf) gene disruption that could mimic some forms of human dilated cardiomyopathy. To investigate the consequences of the maintenance of α-cardiac actin expression in this model, we developed a new transgenic mouse based on Cre/LoxP strategy, allowing together the induction of SRF loss and a compensatory expression of α-cardiac actin. Here, we report that maintenance of α-cardiac actin within cardiomyocytes temporally preserved cytoarchitecture from adverse cardiac remodeling through a positive impact on both structural and transcriptional levels. These protective effects were accompanied in vivo by the decrease of ROS generation and protein carbonylation and the downregulation of NADPH oxidases NOX2 and NOX4. We also show that ectopic expression of α-cardiac actin protects HEK293 cells against oxidative stress induced by H2 O2 . Oxidative stress plays an important role in the development of cardiac remodeling and contributes also to the pathogenesis of heart failure. Taken together, these findings indicate that α-cardiac actin could be involved in the regulation of oxidative stress that is a leading cause of adverse remodeling during dilated cardiomyopathy development.
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Affiliation(s)
- Aude Angelini
- Biological Adaptation and Ageing, Institut de Biologie Paris-Seine (IBPS), CNRS UMR 8256, INSERM ERL U1164, Sorbonne Université, Paris, France
| | - Mark-Alexander Gorey
- Biological Adaptation and Ageing, Institut de Biologie Paris-Seine (IBPS), CNRS UMR 8256, INSERM ERL U1164, Sorbonne Université, Paris, France
| | - Florent Dumont
- Signalling and Cardiovascular Pathophysiology, INSERM UMR-S 1180, Université Paris-Saclay, Châtenay-Malabry, France
| | - Nathalie Mougenot
- Faculté de Médecine, Pierre et Marie Curie, INSERM UMS 28 Phénotypage du petit animal, Sorbonne Université, Paris, France
| | - Maria Chatzifrangkeskou
- Center of Research in Myology, Institut de Myologie, INSERM UMRS 974, Sorbonne Université, Paris, France
| | - Antoine Muchir
- Center of Research in Myology, Institut de Myologie, INSERM UMRS 974, Sorbonne Université, Paris, France
| | - Zhenlin Li
- Biological Adaptation and Ageing, Institut de Biologie Paris-Seine (IBPS), CNRS UMR 8256, INSERM ERL U1164, Sorbonne Université, Paris, France
| | - Mathias Mericskay
- Signalling and Cardiovascular Pathophysiology, INSERM UMR-S 1180, Université Paris-Saclay, Châtenay-Malabry, France
| | - Jean-Francois Decaux
- Biological Adaptation and Ageing, Institut de Biologie Paris-Seine (IBPS), CNRS UMR 8256, INSERM ERL U1164, Sorbonne Université, Paris, France
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13
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A new evolutionary model for the vertebrate actin family including two novel groups. Mol Phylogenet Evol 2019; 141:106632. [DOI: 10.1016/j.ympev.2019.106632] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 09/19/2019] [Accepted: 09/23/2019] [Indexed: 02/06/2023]
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14
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How the central domain of dystrophin acts to bridge F-actin to sarcolemmal lipids. J Struct Biol 2019; 209:107411. [PMID: 31689503 DOI: 10.1016/j.jsb.2019.107411] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 10/07/2019] [Accepted: 10/29/2019] [Indexed: 01/08/2023]
Abstract
Dystrophin is a large intracellular protein that prevents sarcolemmal ruptures by providing a mechanical link between the intracellular actin cytoskeleton and the transmembrane dystroglycan complex. Dystrophin deficiency leads to the severe muscle wasting disease Duchenne Muscular Dystrophy and the milder allelic variant, Becker Muscular Dystrophy (DMD and BMD). Previous work has shown that concomitant interaction of the actin binding domain 2 (ABD2) comprising spectrin like repeats 11 to 15 (R11-15) of the central domain of dystrophin, with both actin and membrane lipids, can greatly increase membrane stiffness. Based on a combination of SAXS and SANS measurements, mass spectrometry analysis of cross-linked complexes and interactive low-resolution simulations, we explored in vitro the molecular properties of dystrophin that allow the formation of ABD2-F-actin and ABD2-membrane model complexes. In dystrophin we identified two subdomains interacting with F-actin, one located in R11 and a neighbouring region in R12 and another one in R15, while a single lipid binding domain was identified at the C-terminal end of R12. Relative orientations of the dystrophin central domain with F-actin and a membrane model were obtained from docking simulation under experimental constraints. SAXS-based models were then built for an extended central subdomain from R4 to R19, including ABD2. Overall results are compatible with a potential F-actin/dystrophin/membrane lipids ternary complex. Our description of this selected part of the dystrophin associated complex bridging muscle cell membrane and cytoskeleton opens the way to a better understanding of how cell muscle scaffolding is maintained through this essential protein.
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15
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Bildyug NB, Khaitlina SY. Redistribution of Sarcomeric Myosin and α-Actinin in Cardiomyocytes in Culture upon the Rearrangement of their Contractile Apparatus. ACTA ACUST UNITED AC 2019. [DOI: 10.1134/s1990519x1905002x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Bildyug N. Extracellular Matrix in Regulation of Contractile System in Cardiomyocytes. Int J Mol Sci 2019; 20:E5054. [PMID: 31614676 PMCID: PMC6834325 DOI: 10.3390/ijms20205054] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/07/2019] [Accepted: 10/09/2019] [Indexed: 12/16/2022] Open
Abstract
The contractile apparatus of cardiomyocytes is considered to be a stable system. However, it undergoes strong rearrangements during heart development as cells progress from their non-muscle precursors. Long-term culturing of mature cardiomyocytes is also accompanied by the reorganization of their contractile apparatus with the conversion of typical myofibrils into structures of non-muscle type. Processes of heart development as well as cell adaptation to culture conditions in cardiomyocytes both involve extracellular matrix changes, which appear to be crucial for the maturation of contractile apparatus. The aim of this review is to analyze the role of extracellular matrix in the regulation of contractile system dynamics in cardiomyocytes. Here, the remodeling of actin contractile structures and the expression of actin isoforms in cardiomyocytes during differentiation and adaptation to the culture system are described along with the extracellular matrix alterations. The data supporting the regulation of actin dynamics by extracellular matrix are highlighted and the possible mechanisms of such regulation are discussed.
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Affiliation(s)
- Natalya Bildyug
- Institute of Cytology, Russian Academy of Sciences, St-Petersburg 194064, Russia.
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17
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Rangrez AY, Kilian L, Stiebeling K, Dittmann S, Schulze-Bahr E, Frey N, Frank D. A cardiac α-actin (ACTC1) p. Gly247Asp mutation inhibits SRF-signaling in vitro in neonatal rat cardiomyocytes. Biochem Biophys Res Commun 2019; 518:500-505. [PMID: 31434612 DOI: 10.1016/j.bbrc.2019.08.081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 08/14/2019] [Indexed: 12/23/2022]
Abstract
We recently identified a novel, heterozygous, and non-synonymous ACTC1 mutation (p.Gly247Asp or G247D) in a large, multi-generational family, causing atrial-septal defect followed by late-onset dilated cardiomyopathy (DCM). Molecular dynamics studies revealed possible actin polymerization defects as G247D mutation resides at the juncture of side-chain interaction, which was indeed confirmed by in vitro actin polymerization assays. Since polymerization/de-polymerization is important for the activation of Rho-GTPase-mediated serum response factor (SRF)-signaling, we studied the effect of G247D mutation using luciferase assay. Overexpression of native human ACTC1 in neonatal rat cardiomyocytes (NRVCMs) strongly activated SRF-signaling both in C2C12 cells and NRVCMs, whereas, G247D mutation abolished this activation. Mechanistically, we found reduced GTP-bound Rho-GTPase and increased nuclear localization of globular actin in NRVCMs overexpressing mutant ACTC1 possibly causing inhibition of SRF-signaling activation. In conclusion, our data suggests that human G247D ACTC1 mutation negatively regulates SRF-signaling likely contributing to the late-onset DCM observed in mutation carrier patients.
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Affiliation(s)
- Ashraf Yusuf Rangrez
- Department of Internal Medicine III, Cardiology and Angiology, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
| | - Lucia Kilian
- Department of Internal Medicine III, Cardiology and Angiology, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Katharina Stiebeling
- Department of Internal Medicine III, Cardiology and Angiology, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Sven Dittmann
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster, Germany
| | - Eric Schulze-Bahr
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster, Germany
| | - Norbert Frey
- Department of Internal Medicine III, Cardiology and Angiology, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Derk Frank
- Department of Internal Medicine III, Cardiology and Angiology, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
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18
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Frank D, Rangrez AY, Friedrich C, Dittmann S, Stallmeyer B, Yadav P, Bernt A, Schulze-Bahr E, Borlepawar A, Zimmermann WH, Peischard S, Seebohm G, Linke WA, Baba HA, Krüger M, Unger A, Usinger P, Frey N, Schulze-Bahr E. Cardiac α-Actin (
ACTC1
) Gene Mutation Causes Atrial-Septal Defects Associated With Late-Onset Dilated Cardiomyopathy. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2019; 12:e002491. [DOI: 10.1161/circgen.119.002491] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background:
Familial atrial septal defect (ASD) has previously been attributed primarily to mutations in cardiac transcription factors. Here, we report a large, multi-generational family (78 members) with ASD combined with a late-onset dilated cardiomyopathy and further characterize the consequences of mutant α-actin.
Methods:
We combined a genome-wide linkage analysis with cell biology, microscopy, and molecular biology tools to characterize a novel
ACTC1
(cardiac α-actin) mutation identified in association with ASD and late-onset dilated cardiomyopathy in a large, multi-generational family.
Results:
Using a genome-wide linkage analysis, the ASD disease locus was mapped to chromosome 15q14 harboring the
ACTC1
gene. In 15 affected family members, a heterozygous, nonsynonymous, and fully penetrant mutation (p. Gly247Asp) was identified in exon 5 of
ACTC1
that was absent in all healthy family members (n=63). In silico tools predicted deleterious consequences of this variant that was found absent in control databases. Ultrastructural analysis of myocardial tissue of one of the mutation carriers showed sarcomeric disarray, myofibrillar degeneration, and increased apoptosis, while cardiac proteomics revealed a significant increase in extracellular matrix proteins. Consistently, structural defects and increased apoptosis were also observed in neonatal rat ventricular cardiomyocytes overexpressing the mutant, but not native human ACTC1. Molecular dynamics studies and additional mechanistic analyses in cardiomyocytes confirmed actin polymerization/turnover defects, thereby affecting contractility.
Conclusions:
A combined phenotype of ASD and late-onset heart failure was caused by a heterozygous, nonsynonymous ACTC1 mutation. Mechanistically, we found a shared molecular mechanism of defective actin signaling and polymerization in both cardiac development and contractile function. Detection of ACTC1 mutations in patients with ASD may thus have further clinical implications with regard to monitoring for (late-onset) dilated cardiomyopathy.
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Affiliation(s)
- Derk Frank
- Department of Internal Medicine III, Cardiology and Angiology, University Medical Center Schleswig-Holstein, Campus Kiel (D.F., A.Y.R., A. Bernt, A. Borlepawar, P.U., N.F.)
- Co-affiliated with DZHK (German Centre for Cardiovascular Research), sites Hamburg/Kiel/Lübeck and Göttingen, Germany (D.F., A.Y.R., A. Bernt, A. Borlepawar, W.H.-Z., W.A.L., N.F.)
| | - Ashraf Yusuf Rangrez
- Department of Internal Medicine III, Cardiology and Angiology, University Medical Center Schleswig-Holstein, Campus Kiel (D.F., A.Y.R., A. Bernt, A. Borlepawar, P.U., N.F.)
- Co-affiliated with DZHK (German Centre for Cardiovascular Research), sites Hamburg/Kiel/Lübeck and Göttingen, Germany (D.F., A.Y.R., A. Bernt, A. Borlepawar, W.H.-Z., W.A.L., N.F.)
| | - Corinna Friedrich
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine (C.F., S.D., B.S., Ellen Schulze-Bahr, S.P., G.S., A.U., Eric Schulze-Bahr), University Hospital Münster
- Institute for Human Genetics (C.F), University Hospital Münster
| | - Sven Dittmann
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine (C.F., S.D., B.S., Ellen Schulze-Bahr, S.P., G.S., A.U., Eric Schulze-Bahr), University Hospital Münster
| | - Birgit Stallmeyer
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine (C.F., S.D., B.S., Ellen Schulze-Bahr, S.P., G.S., A.U., Eric Schulze-Bahr), University Hospital Münster
| | - Pankaj Yadav
- Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Heidelberg (P.Y.)
| | - Alexander Bernt
- Department of Internal Medicine III, Cardiology and Angiology, University Medical Center Schleswig-Holstein, Campus Kiel (D.F., A.Y.R., A. Bernt, A. Borlepawar, P.U., N.F.)
- Co-affiliated with DZHK (German Centre for Cardiovascular Research), sites Hamburg/Kiel/Lübeck and Göttingen, Germany (D.F., A.Y.R., A. Bernt, A. Borlepawar, W.H.-Z., W.A.L., N.F.)
| | - Ellen Schulze-Bahr
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine (C.F., S.D., B.S., Ellen Schulze-Bahr, S.P., G.S., A.U., Eric Schulze-Bahr), University Hospital Münster
| | - Ankush Borlepawar
- Department of Internal Medicine III, Cardiology and Angiology, University Medical Center Schleswig-Holstein, Campus Kiel (D.F., A.Y.R., A. Bernt, A. Borlepawar, P.U., N.F.)
- Co-affiliated with DZHK (German Centre for Cardiovascular Research), sites Hamburg/Kiel/Lübeck and Göttingen, Germany (D.F., A.Y.R., A. Bernt, A. Borlepawar, W.H.-Z., W.A.L., N.F.)
| | - Wolfram-Hubertus Zimmermann
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen (W.H.-Z.)
- Co-affiliated with DZHK (German Centre for Cardiovascular Research), sites Hamburg/Kiel/Lübeck and Göttingen, Germany (D.F., A.Y.R., A. Bernt, A. Borlepawar, W.H.-Z., W.A.L., N.F.)
| | - Stefan Peischard
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine (C.F., S.D., B.S., Ellen Schulze-Bahr, S.P., G.S., A.U., Eric Schulze-Bahr), University Hospital Münster
| | - Guiscard Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine (C.F., S.D., B.S., Ellen Schulze-Bahr, S.P., G.S., A.U., Eric Schulze-Bahr), University Hospital Münster
| | - Wolfgang A. Linke
- Institute of Physiology II (W.A.L.), University Hospital Münster
- Co-affiliated with DZHK (German Centre for Cardiovascular Research), sites Hamburg/Kiel/Lübeck and Göttingen, Germany (D.F., A.Y.R., A. Bernt, A. Borlepawar, W.H.-Z., W.A.L., N.F.)
| | - Hideo A. Baba
- Institute of Pathology, University of Duisburg-Essen (H.A.B.)
| | - Marcus Krüger
- Center for Molecular Medicine Cologne (CMMC), Proteomics Facility, University of Cologne (M.K.)
| | - Andreas Unger
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine (C.F., S.D., B.S., Ellen Schulze-Bahr, S.P., G.S., A.U., Eric Schulze-Bahr), University Hospital Münster
| | - Philip Usinger
- Department of Internal Medicine III, Cardiology and Angiology, University Medical Center Schleswig-Holstein, Campus Kiel (D.F., A.Y.R., A. Bernt, A. Borlepawar, P.U., N.F.)
| | - Norbert Frey
- Department of Internal Medicine III, Cardiology and Angiology, University Medical Center Schleswig-Holstein, Campus Kiel (D.F., A.Y.R., A. Bernt, A. Borlepawar, P.U., N.F.)
- Co-affiliated with DZHK (German Centre for Cardiovascular Research), sites Hamburg/Kiel/Lübeck and Göttingen, Germany (D.F., A.Y.R., A. Bernt, A. Borlepawar, W.H.-Z., W.A.L., N.F.)
| | - Eric Schulze-Bahr
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine (C.F., S.D., B.S., Ellen Schulze-Bahr, S.P., G.S., A.U., Eric Schulze-Bahr), University Hospital Münster
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19
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Guhathakurta P, Prochniewicz E, Grant BD, Peterson KC, Thomas DD. High-throughput screen, using time-resolved FRET, yields actin-binding compounds that modulate actin-myosin structure and function. J Biol Chem 2018; 293:12288-12298. [PMID: 29866882 DOI: 10.1074/jbc.ra118.002702] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/16/2018] [Indexed: 12/20/2022] Open
Abstract
We have used a novel time-resolved FRET (TR-FRET) assay to detect small-molecule modulators of actin-myosin structure and function. Actin-myosin interactions play crucial roles in the generation of cellular force and movement. Numerous mutations and post-translational modifications of actin or myosin disrupt muscle function and cause life-threatening syndromes. Here, we used a FRET biosensor to identify modulators that bind to the actin-myosin interface and alter the structural dynamics of this complex. We attached a fluorescent donor to actin at Cys-374 and a nonfluorescent acceptor to a peptide containing the 12 N-terminal amino acids of the long isoform of skeletal muscle myosin's essential light chain. The binding site on actin of this acceptor-labeled peptide (ANT) overlaps with that of myosin, as indicated by (a) a similar distance observed in the actin-ANT complex as in the actin-myosin complex and (b) a significant decrease in actin-ANT FRET upon binding myosin. A high-throughput FRET screen of a small-molecule library (NCC, 727 compounds), using a unique fluorescence lifetime readout with unprecedented speed and precision, showed that FRET is significantly affected by 10 compounds in the micromolar range. Most of these "hits" alter actin-activated myosin ATPase and affect the microsecond dynamics of actin detected by transient phosphorescence anisotropy. We conclude that the actin-ANT TR-FRET assay enables detection of pharmacologically active compounds that affect actin structural dynamics and actomyosin function. This assay establishes feasibility for the discovery of allosteric modulators of the actin-myosin interaction, with the ultimate goal of developing therapies for muscle disorders.
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Affiliation(s)
- Piyali Guhathakurta
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
| | - Ewa Prochniewicz
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
| | | | | | - David D Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455; Photonic Pharma LLC, Minneapolis, Minnesota 55410.
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20
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Vedula P, Kashina A. The makings of the 'actin code': regulation of actin's biological function at the amino acid and nucleotide level. J Cell Sci 2018; 131:131/9/jcs215509. [PMID: 29739859 DOI: 10.1242/jcs.215509] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The actin cytoskeleton plays key roles in every eukaryotic cell and is essential for cell adhesion, migration, mechanosensing, and contractility in muscle and non-muscle tissues. In higher vertebrates, from birds through to mammals, actin is represented by a family of six conserved genes. Although these genes have evolved independently for more than 100 million years, they encode proteins with ≥94% sequence identity, which are differentially expressed in different tissues, and tightly regulated throughout embryogenesis and adulthood. It has been previously suggested that the existence of such similar actin genes is a fail-safe mechanism to preserve the essential function of actin through redundancy. However, knockout studies in mice and other organisms demonstrate that the different actins have distinct biological roles. The mechanisms maintaining this distinction have been debated in the literature for decades. This Review summarizes data on the functional regulation of different actin isoforms, and the mechanisms that lead to their different biological roles in vivo We focus here on recent studies demonstrating that at least some actin functions are regulated beyond the amino acid level at the level of the actin nucleotide sequence.
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Affiliation(s)
- Pavan Vedula
- Department of Biomedical Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anna Kashina
- Department of Biomedical Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
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21
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Laurini E, Martinelli V, Lanzicher T, Puzzi L, Borin D, Chen SN, Long CS, Lee P, Mestroni L, Taylor MRG, Sbaizero O, Pricl S. Biomechanical defects and rescue of cardiomyocytes expressing pathologic nuclear lamins. Cardiovasc Res 2018; 114:846-857. [PMID: 29432544 PMCID: PMC5909658 DOI: 10.1093/cvr/cvy040] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 01/06/2018] [Accepted: 02/07/2018] [Indexed: 02/07/2023] Open
Abstract
Aims Given the clinical impact of LMNA cardiomyopathies, understanding lamin function will fulfill a clinical need and will lead to advancement in the treatment of heart failure. A multidisciplinary approach combining cell biology, atomic force microscopy (AFM), and molecular modeling was used to analyse the biomechanical properties of human lamin A/C gene (LMNA) mutations (E161K, D192G, N195K) using an in vitro neonatal rat ventricular myocyte model. Methods and results The severity of biomechanical defects due to the three LMNA mutations correlated with the severity of the clinical phenotype. AFM and molecular modeling identified distinctive biomechanical and structural changes, with increasing severity from E161K to N195K and D192G, respectively. Additionally, the biomechanical defects were rescued with a p38 MAPK inhibitor. Conclusions AFM and molecular modeling were able to quantify distinct biomechanical and structural defects in LMNA mutations E161K, D192G, and N195K and correlate the defects with clinical phenotypic severity. Improvements in cellular biomechanical phenotype was demonstrated and may represent a mechanism of action for p38 MAPK inhibition therapy that is now being used in human clinical trials to treat laminopathies.
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Affiliation(s)
- Erik Laurini
- Department of Engineering and Architecture, University of Trieste, 34127 Trieste, Italy
| | - Valentina Martinelli
- International Center for Genetic Engineering and Biotechnology, 34149 Trieste, Italy
| | - Thomas Lanzicher
- Department of Engineering and Architecture, University of Trieste, 34127 Trieste, Italy
| | - Luca Puzzi
- Department of Engineering and Architecture, University of Trieste, 34127 Trieste, Italy
| | - Daniele Borin
- Department of Engineering and Architecture, University of Trieste, 34127 Trieste, Italy
| | - Suet Nee Chen
- Cardiovascular Institute and Adult Medical Genetics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Carlin S Long
- Cardiovascular Institute and Adult Medical Genetics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Patrice Lee
- Array BioPharma Inc., Boulder, CO 80301, USA
| | - Luisa Mestroni
- Cardiovascular Institute and Adult Medical Genetics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Matthew R G Taylor
- Cardiovascular Institute and Adult Medical Genetics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Orfeo Sbaizero
- Department of Engineering and Architecture, University of Trieste, 34127 Trieste, Italy
| | - Sabrina Pricl
- Department of Engineering and Architecture, University of Trieste, 34127 Trieste, Italy
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22
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Dohn TE, Cripps RM. Absence of the Drosophila jump muscle actin Act79B is compensated by up-regulation of Act88F. Dev Dyn 2018; 247:642-649. [PMID: 29318731 PMCID: PMC6118211 DOI: 10.1002/dvdy.24616] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/04/2018] [Accepted: 01/08/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Actins are structural components of the cytoskeleton and muscle, and numerous actin isoforms are found in most organisms. However, many actin isoforms are expressed in distinct patterns allowing each actin to have a specialized function. Numerous studies have demonstrated that actin isoforms both can and cannot compensate for each other under specific circumstances. This allows for an ambiguity of whether isoforms are functionally distinct. RESULTS In this study, we analyzed mutants of Drosophila Act79B, the predominant actin expressed in the adult jump muscle. Functional and structural analysis of the Act79B mutants found the flies to have normal jumping ability and sarcomere structure. Analysis of actin gene expression determined that expression of Act88F, an actin gene normally expressed in the flight muscles, was significantly up-regulated in the jump muscles of mutants. This indicated that loss of Act79B caused expansion of Act88F expression. When we created double mutants of Act79B and Act88F, this abolished the jump ability of the flies and resulted in severe defects in myofibril formation. CONCLUSIONS These results indicate that Act88F can functionally substitute for Act79B in the jump muscle, and that the functional compensation in actin expression in the jump muscles only occurs through Act88F. Developmental Dynamics 247:642-649, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Tracy E. Dohn
- Department of Biology, University of New Mexico, Albuquerque, New Mexico
| | - Richard M. Cripps
- Department of Biology, University of New Mexico, Albuquerque, New Mexico
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23
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Abstract
There are multiple intrinsic mechanisms for diastolic dysfunction ranging from molecular to structural derangements in ventricular myocardium. The molecular mechanisms regulating the progression from normal diastolic function to severe dysfunction still remain poorly understood. Recent studies suggest a potentially important role of core cardio-enriched transcription factors (TFs) in the control of cardiac diastolic function in health and disease through their ability to regulate the expression of target genes involved in the process of adaptive and maladaptive cardiac remodeling. The current relevant findings on the role of a variety of such TFs (TBX5, GATA-4/6, SRF, MYOCD, NRF2, and PITX2) in cardiac diastolic dysfunction and failure are updated, emphasizing their potential as promising targets for novel treatment strategies. In turn, the new animal models described here will be key tools in determining the underlying molecular mechanisms of disease. Since diastolic dysfunction is regulated by various TFs, which are also involved in cross talk with each other, there is a need for more in-depth research from a biomedical perspective in order to establish efficient therapeutic strategies.
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24
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O'Rourke AR, Lindsay A, Tarpey MD, Yuen S, McCourt P, Nelson DM, Perrin BJ, Thomas DD, Spangenburg EE, Lowe DA, Ervasti JM. Impaired muscle relaxation and mitochondrial fission associated with genetic ablation of cytoplasmic actin isoforms. FEBS J 2018; 285:481-500. [PMID: 29265728 DOI: 10.1111/febs.14367] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 11/06/2017] [Accepted: 12/13/2017] [Indexed: 12/28/2022]
Abstract
While α-actin isoforms predominate in adult striated muscle, skeletal muscle-specific knockouts (KOs) of nonmuscle cytoplasmic βcyto - or γcyto -actin each cause a mild, but progressive myopathy effected by an unknown mechanism. Using transmission electron microscopy, we identified morphological abnormalities in both the mitochondria and the sarcoplasmic reticulum (SR) in aged muscle-specific βcyto - and γcyto -actin KO mice. We found βcyto - and γcyto -actin proteins to be enriched in isolated mitochondrial-associated membrane preparations, which represent the interface between mitochondria and sarco-endoplasmic reticulum important in signaling and mitochondrial dynamics. We also measured significantly elongated and interconnected mitochondrial morphologies associated with a significant decrease in mitochondrial fission events in primary mouse embryonic fibroblasts lacking βcyto - and/or γcyto -actin. Interestingly, mitochondrial respiration in muscle was not measurably affected as oxygen consumption was similar in skeletal muscle fibers from 12 month-old muscle-specific βcyto - and γcyto -actin KO mice. Instead, we found that the maximal rate of relaxation after isometric contraction was significantly slowed in muscles of 12-month-old βcyto - and γcyto -actin muscle-specific KO mice. Our data suggest that impaired Ca2+ re-uptake may presage development of the observed SR morphological changes in aged mice while providing a potential pathological mechanism for the observed myopathy.
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Affiliation(s)
- Allison R O'Rourke
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA
| | - Angus Lindsay
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Michael D Tarpey
- Department of Physiology, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, USA
| | - Samantha Yuen
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Preston McCourt
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - D'anna M Nelson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Benjamin J Perrin
- Department of Biology, Indiana University-Purdue University Indianapolis, IN, USA
| | - David D Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Espen E Spangenburg
- Department of Physiology, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, USA
| | - Dawn A Lowe
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
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25
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Min S, Yoon W, Cho H, Chung J. Misato underlies visceral myopathy in Drosophila. Sci Rep 2017; 7:17700. [PMID: 29255146 PMCID: PMC5735100 DOI: 10.1038/s41598-017-17961-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 12/01/2017] [Indexed: 11/12/2022] Open
Abstract
Genetic mechanisms for the pathogenesis of visceral myopathy (VM) have been rarely demonstrated. Here we report the visceral role of misato (mst) in Drosophila and its implications for the pathogenesis of VM. Depletion of mst using three independent RNAi lines expressed by a pan-muscular driver elicited characteristic symptoms of VM, such as abnormal dilation of intestinal tracts, reduced gut motility, feeding defects, and decreased life span. By contrast, exaggerated expression of mst reduced intestine diameters, but increased intestinal motilities along with thickened muscle fibers, demonstrating a critical role of mst in the visceral muscle. Mst expression was detected in the adult intestine with its prominent localization to actin filaments and was required for maintenance of intestinal tubulin and actomyosin structures. Consistent with the subcellular localization of Mst, the intestinal defects induced by mst depletion were dramatically rescued by exogenous expression of an actin member. Upon ageing the intestinal defects were deteriorative with marked increase of apoptotic responses in the visceral muscle. Taken together, we propose the impairment of actomyosin structures induced by mst depletion in the visceral muscle as a pathogenic mechanism for VM.
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Affiliation(s)
- Soohong Min
- National Creative Research Initiatives Center for Energy Homeostasis Regulation, Institute of Molecular Biology and Genetics, Seoul National University, 1 Gwanak-Ro, Gwanak-Gu, Seoul, 08826, Republic of Korea.,Harvard Medical School, Department of Cell Biology, 240 Longwood Avenue, Seeley-Mudd Building, Boston, MA, 02115, USA
| | - Woongchang Yoon
- National Creative Research Initiatives Center for Energy Homeostasis Regulation, Institute of Molecular Biology and Genetics, Seoul National University, 1 Gwanak-Ro, Gwanak-Gu, Seoul, 08826, Republic of Korea.,School of Biological Sciences, Seoul National University, 1 Gwanak-Ro, Gwanak-Gu, Seoul, 08826, Republic of Korea
| | - Hyunho Cho
- National Creative Research Initiatives Center for Energy Homeostasis Regulation, Institute of Molecular Biology and Genetics, Seoul National University, 1 Gwanak-Ro, Gwanak-Gu, Seoul, 08826, Republic of Korea.,School of Biological Sciences, Seoul National University, 1 Gwanak-Ro, Gwanak-Gu, Seoul, 08826, Republic of Korea
| | - Jongkyeong Chung
- National Creative Research Initiatives Center for Energy Homeostasis Regulation, Institute of Molecular Biology and Genetics, Seoul National University, 1 Gwanak-Ro, Gwanak-Gu, Seoul, 08826, Republic of Korea. .,School of Biological Sciences, Seoul National University, 1 Gwanak-Ro, Gwanak-Gu, Seoul, 08826, Republic of Korea.
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26
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Abstract
Cardiac and skeletal striated muscles are intricately designed machines responsible for muscle contraction. Coordination of the basic contractile unit, the sarcomere, and the complex cytoskeletal networks are critical for contractile activity. The sarcomere is comprised of precisely organized individual filament systems that include thin (actin), thick (myosin), titin, and nebulin. Connecting the sarcomere to other organelles (e.g., mitochondria and nucleus) and serving as the scaffold to maintain cellular integrity are the intermediate filaments. The costamere, on the other hand, tethers the sarcomere to the cell membrane. Unique structures like the intercalated disc in cardiac muscle and the myotendinous junction in skeletal muscle help synchronize and transmit force. Intense investigation has been done on many of the proteins that make up these cytoskeletal assemblies. Yet the details of their function and how they interconnect have just started to be elucidated. A vast number of human myopathies are contributed to mutations in muscle proteins; thus understanding their basic function provides a mechanistic understanding of muscle disorders. In this review, we highlight the components of striated muscle with respect to their interactions, signaling pathways, functions, and connections to disease. © 2017 American Physiological Society. Compr Physiol 7:891-944, 2017.
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Affiliation(s)
- Christine A Henderson
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
| | - Christopher G Gomez
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
| | - Stefanie M Novak
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
| | - Lei Mi-Mi
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
| | - Carol C Gregorio
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
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27
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Dash SN, Narumanchi S, Paavola J, Perttunen S, Wang H, Lakkisto P, Tikkanen I, Lehtonen S. Sept7b is required for the subcellular organization of cardiomyocytes and cardiac function in zebrafish. Am J Physiol Heart Circ Physiol 2017; 312:H1085-H1095. [DOI: 10.1152/ajpheart.00394.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 02/28/2017] [Accepted: 03/19/2017] [Indexed: 12/22/2022]
Abstract
Myofibrils made up of actin, myosin, and associated proteins generate the contractile force in muscle, and, consequently, mutations in these proteins may lead to heart failure. Septins are a conserved family of small GTPases that associate with actin filaments, microtubules, and cellular membranes. Despite the importance of septins in cytoskeleton organization, their role in cardiomyocyte organization and function is poorly characterized. Here, we show that septin 7 is expressed in both embryonic and adult zebrafish hearts and elucidate the physiological significance of sept7b, the zebrafish ortholog of human septin 7, in the heart in embryonic and larval zebrafish. Knockdown of sept7b reduced F-actin and α-cardiac actin expression in the heart and caused disorganization of actin filaments. Electron microscopy of sept7b-depleted larvae showed disorganization of heart myofibrils and partial detachment from Z-disks. Functional studies revealed that knockdown of sept7b leads to reduced ventricular dimensions, contractility, and cardiac output. Furthermore, we found that depletion of sept7b diminished the expression of retinaldehyde dehydrogenase 2, which catalyzes the synthesis of retinoic acid necessary for heart morphogenesis. We further observed that the sept7b and retinoic acid signaling pathways converge to regulate cardiac function. Together, these results specify an essential role for sept7b in the contractile function of the heart. NEW & NOTEWORTHY Knockdown of the zebrafish ortholog of human septin 7 ( sept7b) destabilizes cardiac actin and reduces ventricular dimensions, contractility, and cardiac output in larval zebrafish, indicating that sept7b is essential for cardiac function. We further found that sept7b and retinoic acid signaling pathways converge to regulate cardiac function. These data prompt further studies defining the role of sept7b in cardiomyopathies.
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Affiliation(s)
| | - Suneeta Narumanchi
- Unit of Cardiovascular Research, Minerva Institute for Medical Research, Biomedicum Helsinki, Helsinki, Finland
| | - Jere Paavola
- Unit of Cardiovascular Research, Minerva Institute for Medical Research, Biomedicum Helsinki, Helsinki, Finland
- Internal Medicine, Jorvi Hospital, Helsinki University Hospital, Espoo, Finland
| | - Sanni Perttunen
- Unit of Cardiovascular Research, Minerva Institute for Medical Research, Biomedicum Helsinki, Helsinki, Finland
| | - Hong Wang
- Department of Pathology, University of Helsinki, Helsinki, Finland
| | - Päivi Lakkisto
- Unit of Cardiovascular Research, Minerva Institute for Medical Research, Biomedicum Helsinki, Helsinki, Finland
- Clinical Chemistry and Hematology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; and
| | - Ilkka Tikkanen
- Unit of Cardiovascular Research, Minerva Institute for Medical Research, Biomedicum Helsinki, Helsinki, Finland
- Abdominal Center, Nephrology, Helsinki University Hospital, Helsinki, Finland
| | - Sanna Lehtonen
- Department of Pathology, University of Helsinki, Helsinki, Finland
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28
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Moradi M, Sivadasan R, Saal L, Lüningschrör P, Dombert B, Rathod RJ, Dieterich DC, Blum R, Sendtner M. Differential roles of α-, β-, and γ-actin in axon growth and collateral branch formation in motoneurons. J Cell Biol 2017; 216:793-814. [PMID: 28246119 PMCID: PMC5346967 DOI: 10.1083/jcb.201604117] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 11/11/2016] [Accepted: 01/17/2017] [Indexed: 12/17/2022] Open
Abstract
α-, β-, and γ-actin differentially regulate cytoskeletal dynamics and stability in axons of motoneurons. Locally translated α-actin contributes to stable actin filaments in axonal branches, whereas β- and γ-actin give rise to highly dynamic filaments that modulate growth cone dynamics. Axonal branching and terminal arborization are fundamental events during the establishment of synaptic connectivity. They are triggered by assembly of actin filaments along axon shafts giving rise to filopodia. The specific contribution of the three actin isoforms, Actα, Actβ, and Actγ, to filopodia stability and dynamics during this process is not well understood. Here, we report that Actα, Actβ, and Actγ isoforms are expressed in primary mouse motoneurons and their transcripts are translocated into axons. shRNA-mediated depletion of Actα reduces axonal filopodia dynamics and disturbs collateral branch formation. Knockdown of Actβ reduces dynamic movements of growth cone filopodia and impairs presynaptic differentiation. Ablation of Actβ or Actγ leads to compensatory up-regulation of the two other isoforms, which allows maintenance of total actin levels and preserves F-actin polymerization. Collectively, our data provide evidence for specific roles of different actin isoforms in spatial regulation of actin dynamics and stability in axons of developing motoneurons.
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Affiliation(s)
- Mehri Moradi
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Rajeeve Sivadasan
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Lena Saal
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Patrick Lüningschrör
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Benjamin Dombert
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Reena Jagdish Rathod
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Daniela C Dieterich
- Institute for Pharmacology and Toxicology, Medical Faculty, University of Magdeburg, 39120 Magdeburg, Germany.,Center for Behavioral Brain Sciences, Medical Faculty, University of Magdeburg, 39120 Magdeburg, Germany
| | - Robert Blum
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
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29
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Lanzicher T, Martinelli V, Long CS, Del Favero G, Puzzi L, Borelli M, Mestroni L, Taylor MRG, Sbaizero O. AFM single-cell force spectroscopy links altered nuclear and cytoskeletal mechanics to defective cell adhesion in cardiac myocytes with a nuclear lamin mutation. Nucleus 2016; 6:394-407. [PMID: 26309016 DOI: 10.1080/19491034.2015.1084453] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Previous investigations suggested that lamin A/C gene (LMNA) mutations, which cause a variety of human diseases including muscular dystrophies and cardiomyopathies, alter the nuclear mechanical properties. We hypothesized that biomechanical changes may extend beyond the nucleus.
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Affiliation(s)
- Thomas Lanzicher
- a Department of Engineering and Architecture ; University of Trieste ; Trieste Italy
| | - Valentina Martinelli
- a Department of Engineering and Architecture ; University of Trieste ; Trieste Italy.,b International Center for Genetic Engineering and Biotechnology ; Trieste Italy
| | - Carlin S Long
- c Cardiovascular Institute & Adult Medical Genetics; University of Colorado Denver Anschutz Medical Campus ; CO USA
| | - Giorgia Del Favero
- d Department of Food Chemistry and Toxicology ; University of Vienna ; Waehringer Str. 38A-1090 Vienna Austria
| | - Luca Puzzi
- a Department of Engineering and Architecture ; University of Trieste ; Trieste Italy
| | - Massimo Borelli
- e Department of Life Sciences ; University of Trieste ; Trieste Italy
| | - Luisa Mestroni
- c Cardiovascular Institute & Adult Medical Genetics; University of Colorado Denver Anschutz Medical Campus ; CO USA
| | - Matthew R G Taylor
- c Cardiovascular Institute & Adult Medical Genetics; University of Colorado Denver Anschutz Medical Campus ; CO USA
| | - Orfeo Sbaizero
- a Department of Engineering and Architecture ; University of Trieste ; Trieste Italy.,c Cardiovascular Institute & Adult Medical Genetics; University of Colorado Denver Anschutz Medical Campus ; CO USA
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30
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Hutter-Schmid B, Humpel C. Alpha-Smooth Muscle Actin mRNA and Protein Are Increased in Isolated Brain Vessel Extracts of Alzheimer Mice. Pharmacology 2016; 98:251-260. [PMID: 27463512 DOI: 10.1159/000448007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 06/24/2016] [Indexed: 12/22/2022]
Abstract
Alzheimer's disease (AD) is a severe neurodegenerative disorder of the brain, characterized by extracellular beta-amyloid (Aβ) plaques, intracellular tau pathology, neurodegeneration and inflammation. There is clear evidence that the blood-brain barrier is damaged in AD and that vessel function is impaired. Alpha-smooth muscle actin (αSMA) is a prominent protein expressed on brain vessels, especially in cells located closer to the arteriole end of the capillaries, which possibly influences the blood vessel contraction. The aim of the present study was to observe αSMA protein and mRNA expression in isolated brain vessel extracts and cortex in an Alzheimer mouse model with strong Aβ plaque deposition. Our data revealed a prominent expression of αSMA protein in isolated brain vessel extracts of AD mice by Western blot analysis. Immunostaining showed that these vessels were associated with Aβ plaques. Quantitative real-time PCR analysis confirmed this increase at the mRNA expression level and showed a significant increase of transforming growth factor beta-1 mRNA expression in AD mice. In situ hybridization demonstrated a strong expression pattern of αSMA mRNA in the whole cortex and hippocampus. In conclusion, our data provide evidence that αSMA protein and mRNA are enhanced in vessels in an AD mouse model, possibly counteracting vessel malfunction in AD.
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Affiliation(s)
- Bianca Hutter-Schmid
- Department of Psychiatry, Psychotherapy and Psychosomatics, Laboratory of Psychiatry and Experimental Alzheimer's Research, Medical University of Innsbruck, Innsbruck, Austria
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31
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A gain-of-function ACTC1 3'UTR mutation that introduces a miR-139-5p target site may be associated with a dominant familial atrial septal defect. Sci Rep 2016; 6:25404. [PMID: 27139165 PMCID: PMC4853704 DOI: 10.1038/srep25404] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 04/18/2016] [Indexed: 12/29/2022] Open
Abstract
The ostium secundum atrial septal defect (ASDII) is the most common type of congenital heart disease and is characterized by a left to right shunting of oxygenated blood caused by incomplete closure of the septum secundum. We identified a familial form of isolated ASDII that affects four individuals in a family of five and shows autosomal dominant inheritance. By whole genome sequencing, we discovered a new mutation (c.*1784T > C) in the 3′-untranslated region (3′UTR) of ACTC1, which encodes the predominant actin in the embryonic heart. Further analysis demonstrated that the c.*1784T > C mutation results in a new target site for miRNA-139-5p, a microRNA that is involved in cell migration, invasion, and proliferation. Functional analysis demonstrated that the c.*1784T > C mutation specifically downregulates gene expression in a luciferase assay. Additionally, miR-139-5p mimic causes further decrease, whereas miR-139-5p inhibitor can dramatically rescue the decline in gene expression caused by this mutation. These findings suggest that the familial ASDII may be a result of an ACTC1 3′UTR gain-of-function mutation caused by the introduction of a new miR-139-5p target site. Our results provide the first evidence of a pathogenic mutation in the ACTC1 3′UTR that may be associated with familial isolated ASDII.
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32
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Morioka K, Takano-Ohmuro H. Localizations of γ-Actins in Skin, Hair, Vibrissa, Arrector Pili Muscle and Other Hair Appendages of Developing Rats. Acta Histochem Cytochem 2016; 49:47-65. [PMID: 27222613 PMCID: PMC4858540 DOI: 10.1267/ahc.15031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 02/16/2016] [Indexed: 11/22/2022] Open
Abstract
Six isoforms of actins encoded by different genes have been identified in mammals including α-cardiac, α-skeletal, α-smooth muscle (α-SMA), β-cytoplasmic, γ-smooth muscle (γ-SMA), and γ-cytoplasmic actins (γ-CYA). In a previous study we showed the localization of α-SMA and other cytoskeletal proteins in the hairs and their appendages of developing rats (Morioka K., et al. (2011) Acta Histochem. Cytochem. 44, 141–153), and herein we determined the localization of γ type actins in the same tissues and organs by immunohistochemical staining. Our results indicate that the expression of γ-SMA and γ-CYA is suggested to be poor in actively proliferating tissues such as the basal layer of the epidermis and the hair matrix in the hair bulb, and as well as in highly keratinized tissues such as the hair cortex and hair cuticle. In contrast, the expression of γ-actins were high in the spinous layer, granular layer, hair shaft, and inner root sheath, during their active differentiations. In particular, the localization of γ-SMA was very similar to that of α-SMA. It was located not only in the arrector pili muscles and muscles in the dermis, but also in the dermal sheath and in a limited area of the outer root sheath in both the hair and vibrissal follicles. The γ-CYA was suggested to be co-localized with γ-SMA in the dermal sheath, outer root sheath, and arrector pili muscles. Sparsely distributed dermal cells expressed both types of γ-actin. The expression of γ-actins is suggested to undergo dynamic changes according to the proliferation and differentiation of the skin and hair-related cells.
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Affiliation(s)
- Kiyokazu Morioka
- Research Institute of Pharmaceutical Sciences, Musashino University
- The Tokyo Metropolitan Institute of Medical Science
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33
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Bildyug N, Bozhokina E, Khaitlina S. Contribution of α-smooth muscle actin and extracellular matrix to the in vitro reorganization of cardiomyocyte contractile system. Cell Biol Int 2016; 40:472-7. [DOI: 10.1002/cbin.10577] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 12/23/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Natalya Bildyug
- Department of Cell Culture; Institute of Cytology RAS; Saint-Petersburg 194064 Russia
| | - Ekaterina Bozhokina
- Department of Cell Culture; Institute of Cytology RAS; Saint-Petersburg 194064 Russia
| | - Sofia Khaitlina
- Department of Cell Culture; Institute of Cytology RAS; Saint-Petersburg 194064 Russia
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Shimura D, Kusakari Y, Sasano T, Nakashima Y, Nakai G, Jiao Q, Jin M, Yokota T, Ishikawa Y, Nakano A, Goda N, Minamisawa S. Heterozygous deletion of sarcolipin maintains normal cardiac function. Am J Physiol Heart Circ Physiol 2016; 310:H92-103. [DOI: 10.1152/ajpheart.00411.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 10/21/2015] [Indexed: 11/22/2022]
Abstract
Sarcolipin (SLN) is a small proteolipid and a regulator of sarco(endo)plasmic reticulum Ca2+-ATPase. In heart tissue, SLN is exclusively expressed in the atrium. Previously, we inserted Cre recombinase into the endogenous SLN locus by homologous recombination and succeeded in generating SLN-Cre knockin (SlnCre/+) mice. This SlnCre/+ mouse can be used to generate an atrium-specific gene-targeting mutant, and it is based on the Cre-loxP system. In the present study, we used adult SlnCre/+ mice atria and analyzed the effects of heterozygous SLN deletion by Cre knockin before use as the gene targeting mouse. Both SLN mRNA and protein levels were decreased in SlnCre/+ mouse atria, but there were no morphological, physiological, or molecular biological abnormalities. The properties of contractility and Ca2+ handling were similar to wild-type (WT) mice, and expression levels of several stress markers and sarcoplasmic reticulum-related protein levels were not different between SlnCre/+ and WT mice. Moreover, there was no significant difference in sarco(endo)plasmic reticulum Ca2+-ATPase activity between the two groups. We showed that SlnCre/+ mice were not significantly different from WT mice in all aspects that were examined. The present study provides basic characteristics of SlnCre/+ mice and possibly information on the usefulness of SlnCre/+ mice as an atrium-specific gene-targeting model.
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Affiliation(s)
- Daisuke Shimura
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
| | - Yoichiro Kusakari
- Department of Cell Physiology, The Jikei University School of Medicine, Tokyo, Japan
| | - Tetsuo Sasano
- Department of Biofunctional Informatics, Tokyo Medical and Dental University, Tokyo, Japan
| | | | - Gaku Nakai
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
| | - Qibin Jiao
- Department of Cardiology, The Affiliated Hospital of Hangzhou Normal University, Institute of Ageing Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Meihua Jin
- Cardiovascular Research Institute, Yokohama City University, Kanagawa, Japan
| | - Tomohiro Yokota
- Departments of Anesthesiology, Physiology and Medicine, Molecular Biology Institute, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Yoshihiro Ishikawa
- Cardiovascular Research Institute, Yokohama City University, Kanagawa, Japan
| | - Atsushi Nakano
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, California
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, California
- Jonsson Comprehensive Cancer Center, University of California, Los Angeles, California; and
- Molecular Biology Institute, University of California, Los Angeles, California
| | - Nobuhito Goda
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
| | - Susumu Minamisawa
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
- Department of Cell Physiology, The Jikei University School of Medicine, Tokyo, Japan
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Abstract
Actin is the central building block of the actin cytoskeleton, a highly regulated filamentous network enabling dynamic processes of cells and simultaneously providing structure. Mammals have six actin isoforms that are very conserved and thus share common functions. Tissue-specific expression in part underlies their differential roles, but actin isoforms also coexist in various cell types and tissues, suggesting specific functions and preferential interaction partners. Gene deletion models, antibody-based staining patterns, gene silencing effects, and the occurrence of isoform-specific mutations in certain diseases have provided clues for specificity on the subcellular level and its consequences on the organism level. Yet, the differential actin isoform functions are still far from understood in detail. Biochemical studies on the different isoforms in pure form are just emerging, and investigations in cells have to deal with a complex and regulated system, including compensatory actin isoform expression.
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Affiliation(s)
- Christophe Ampe
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium.
| | - Marleen Van Troys
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
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Kelloniemi A, Szabo Z, Serpi R, Näpänkangas J, Ohukainen P, Tenhunen O, Kaikkonen L, Koivisto E, Bagyura Z, Kerkelä R, Leosdottir M, Hedner T, Melander O, Ruskoaho H, Rysä J. The Early-Onset Myocardial Infarction Associated PHACTR1 Gene Regulates Skeletal and Cardiac Alpha-Actin Gene Expression. PLoS One 2015; 10:e0130502. [PMID: 26098115 PMCID: PMC4476650 DOI: 10.1371/journal.pone.0130502] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 05/19/2015] [Indexed: 11/19/2022] Open
Abstract
The phosphatase and actin regulator 1 (PHACTR1) locus is a very commonly identified hit in genome-wide association studies investigating coronary artery disease and myocardial infarction (MI). However, the function of PHACTR1 in the heart is still unknown. We characterized the mechanisms regulating Phactr1 expression in the heart, used adenoviral gene delivery to investigate the effects of Phactr1 on cardiac function, and analyzed the relationship between MI associated PHACTR1 allele and cardiac function in human subjects. Phactr1 mRNA and protein levels were markedly reduced (60%, P<0.01 and 90%, P<0.001, respectively) at 1 day after MI in rats. When the direct myocardial effects of Phactr1 were studied, the skeletal α-actin to cardiac α-actin isoform ratio was significantly higher (1.5-fold, P<0.05) at 3 days but 40% lower (P<0.05) at 2 weeks after adenovirus-mediated Phactr1 gene delivery into the anterior wall of the left ventricle. Similarly, the skeletal α-actin to cardiac α-actin ratio was lower at 2 weeks in infarcted hearts overexpressing Phactr1. In cultured neonatal cardiac myocytes, adenovirus-mediated Phactr1 overexpression for 48 hours markedly increased the skeletal α-actin to cardiac α-actin ratio, this being associated with an enhanced DNA binding activity of serum response factor. Phactr1 overexpression exerted no major effects on the expression of other cardiac genes or LV structure and function in normal and infarcted hearts during 2 weeks’ follow-up period. In human subjects, MI associated PHACTR1 allele was not associated significantly with cardiac function (n = 1550). Phactr1 seems to regulate the skeletal to cardiac α-actin isoform ratio.
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Affiliation(s)
- Annina Kelloniemi
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
| | - Zoltan Szabo
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
| | - Raisa Serpi
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
| | - Juha Näpänkangas
- Department of Pathology, Oulu University Hospital, University of Oulu, Oulu, Finland
| | - Pauli Ohukainen
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
| | - Olli Tenhunen
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
| | - Leena Kaikkonen
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
| | - Elina Koivisto
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
| | - Zsolt Bagyura
- Heart Center, Semmelweis University, Budapest, Hungary
| | - Risto Kerkelä
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
- Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Oulu, Finland
| | | | - Thomas Hedner
- Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Olle Melander
- Lund University, Department of Clinical Sciences, Malmö, Sweden
| | - Heikki Ruskoaho
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
- * E-mail: (JR); (HR)
| | - Jaana Rysä
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
- * E-mail: (JR); (HR)
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Kandasamy MK, McKinney EC, Roy E, Meagher RB. Ascomycete fungal actins differentially support plant spatial cell and organ development. Cytoskeleton (Hoboken) 2015; 72:80-92. [PMID: 25428798 DOI: 10.1002/cm.21198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 11/18/2014] [Accepted: 11/23/2014] [Indexed: 01/18/2023]
Abstract
Actin interacts with a wide variety of cytoplasmic and nuclear proteins to support spatial development in nearly all eukaryotes. Null mutations in plant vegetative actins produce dramatically altered cell, tissue, and organ morphologies. Animal cytoplasmic actins (e.g., human HsACTB, HsACTG1) and some ancestral protist actins fully suppress these mutant phenotypes suggesting that some animal, plant, and protist actins share functional competence for spatial development. Considering that fungi have a phylogenetic origin closer to animals than plants, we were interested to explore whether the fungal actins may have this same capacity to function in plants and support development. We ectopically expressed actins from four highly divergent ascomycete fungi in two different Arabidopsis double vegetative actin null mutants. We found that expression of actin from the earliest diverging ascomycete subphyla, the archiascomycete Schizosaccharomyces pombe, qualitatively and quantitatively suppressed the root cell polarity and root organ developmental defects of act8/act7 mutants and the root-hairless cell elongation phenotype of act2/act8 mutants. Interestingly, the actin from the pyrenomycete Neurospora crassa was modestly effective in the suppression of vegetative actin mutant phenotypes. In contrast, actins from the saccharomycetes Saccharomyces cerevisiae and Candida albicans were unable to support any aspect of plant development, and moreover induced severe dwarfism and sterility. These data imply that basal fungi inherited an actin with full competence for spatial development from their protist ancestor and maintained it via non-progressive sequence evolution, while the later more derived fungal species lost these activities.
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Affiliation(s)
- Muthugapatti K Kandasamy
- Department of Genetics, Davison Life Sciences Complex, University of Georgia, Athens, Georgia; Biomedical Microscopy Core, Coverdell Center, University of Georgia, Athens, Georgia
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Fediuk J, Dakshinamurti S. A role for actin polymerization in persistent pulmonary hypertension of the newborn. Can J Physiol Pharmacol 2015; 93:185-94. [PMID: 25695400 DOI: 10.1139/cjpp-2014-0413] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Persistent pulmonary hypertension of the newborn (PPHN) is defined as the failure of normal pulmonary vascular relaxation at birth. Hypoxia is known to impede postnatal disassembly of the actin cytoskeleton in pulmonary arterial myocytes, resulting in elevation of smooth muscle α-actin and γ-actin content in elastic and resistance pulmonary arteries in PPHN compared with age-matched controls. This review examines the original histological characterization of PPHN with attention to cytoskeletal structural remodeling and actin isoform abundance, reviews the existing evidence for understanding the biophysical and biochemical forces at play during neonatal circulatory transition, and specifically addresses the role of the cortical actin architecture, primarily identified as γ-actin, in the transduction of mechanical force in the hypoxic PPHN pulmonary circuit.
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Affiliation(s)
- Jena Fediuk
- Biology of Breathing Group, Manitoba Institute of Child Health, 715 McDermot Avenue, Winnipeg, MB R3E 3P4, Canada., Department of Physiology, University of Manitoba, Winnipeg, Manitoba, Canada
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39
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Yin Z, Ren J, Guo W. Sarcomeric protein isoform transitions in cardiac muscle: a journey to heart failure. Biochim Biophys Acta Mol Basis Dis 2014; 1852:47-52. [PMID: 25446994 DOI: 10.1016/j.bbadis.2014.11.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 10/27/2014] [Accepted: 11/04/2014] [Indexed: 01/05/2023]
Abstract
Sarcomeric protein isoforms are mainly governed by alternative promoter-driven expression, distinct gene expression, gene mutation and alternative mRNA splicing. The transitions of sarcomeric proteins have been implicated to play a role in the onset and development of human heart failure. In this mini-review, we summarized isoform transitions of several most widely examined sarcomeric proteins including myosin, actin, troponin, tropomyosin, titin and myosin binding protein-C, and the consequence of these abnormal isoform transitions. Even though the isoform transitions of sarcomeric proteins have been described in individual sarcomeric protein reviews, no concise summary of these results has been presented previously. This review is intended to fill this gap and discuss possible future perspectives.
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Affiliation(s)
- Zhiyong Yin
- Animal Science, College of Agriculture and Natural Resources, University of WY, Laramie WY82071, USA; Department of Cardiology, Xi Jing Hospital, Fourth Military Medical University, Xi'an 710032, PR China
| | - Jun Ren
- Center for Cardiovascular Research and Alternative Medicine, College of Health Science, University of WY, Laramie WY82071, USA
| | - Wei Guo
- Animal Science, College of Agriculture and Natural Resources, University of WY, Laramie WY82071, USA; Center for Cardiovascular Research and Alternative Medicine, College of Health Science, University of WY, Laramie WY82071, USA.
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40
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Masedunskas A, Appaduray M, Hardeman EC, Gunning PW. What makes a model system great? INTRAVITAL 2014. [DOI: 10.4161/intv.26287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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41
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Clowes C, Boylan MGS, Ridge LA, Barnes E, Wright JA, Hentges KE. The functional diversity of essential genes required for mammalian cardiac development. Genesis 2014; 52:713-37. [PMID: 24866031 PMCID: PMC4141749 DOI: 10.1002/dvg.22794] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 05/22/2014] [Accepted: 05/23/2014] [Indexed: 01/04/2023]
Abstract
Genes required for an organism to develop to maturity (for which no other gene can compensate) are considered essential. The continuing functional annotation of the mouse genome has enabled the identification of many essential genes required for specific developmental processes including cardiac development. Patterns are now emerging regarding the functional nature of genes required at specific points throughout gestation. Essential genes required for development beyond cardiac progenitor cell migration and induction include a small and functionally homogenous group encoding transcription factors, ligands and receptors. Actions of core cardiogenic transcription factors from the Gata, Nkx, Mef, Hand, and Tbx families trigger a marked expansion in the functional diversity of essential genes from midgestation onwards. As the embryo grows in size and complexity, genes required to maintain a functional heartbeat and to provide muscular strength and regulate blood flow are well represented. These essential genes regulate further specialization and polarization of cell types along with proliferative, migratory, adhesive, contractile, and structural processes. The identification of patterns regarding the functional nature of essential genes across numerous developmental systems may aid prediction of further essential genes and those important to development and/or progression of disease. genesis 52:713–737, 2014.
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Affiliation(s)
- Christopher Clowes
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, United Kingdom
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42
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Transcriptional analysis of apoptotic cerebellar granule neurons following rescue by gastric inhibitory polypeptide. Int J Mol Sci 2014; 15:5596-622. [PMID: 24694544 PMCID: PMC4013584 DOI: 10.3390/ijms15045596] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/04/2014] [Accepted: 03/17/2014] [Indexed: 12/31/2022] Open
Abstract
Apoptosis triggered by exogenous or endogenous stimuli is a crucial phenomenon to determine the fate of neurons, both in physiological and in pathological conditions. Our previous study established that gastric inhibitory polypeptide (Gip) is a neurotrophic factor capable of preventing apoptosis of cerebellar granule neurons (CGNs), during its pre-commitment phase. In the present study, we conducted whole-genome expression profiling to obtain a comprehensive view of the transcriptional program underlying the rescue effect of Gip in CGNs. By using DNA microarray technology, we identified 65 genes, we named survival related genes, whose expression is significantly de-regulated following Gip treatment. The expression levels of six transcripts were confirmed by real-time quantitative polymerase chain reaction. The proteins encoded by the survival related genes are functionally grouped in the following categories: signal transduction, transcription, cell cycle, chromatin remodeling, cell death, antioxidant activity, ubiquitination, metabolism and cytoskeletal organization. Our data outline that Gip supports CGNs rescue via a molecular framework, orchestrated by a wide spectrum of gene actors, which propagate survival signals and support neuronal viability.
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43
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Preller M, Manstein D. Myosin Structure, Allostery, and Mechano-Chemistry. Structure 2013; 21:1911-22. [DOI: 10.1016/j.str.2013.09.015] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 09/19/2013] [Accepted: 09/25/2013] [Indexed: 01/10/2023]
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Rockey DC, Weymouth N, Shi Z. Smooth muscle α actin (Acta2) and myofibroblast function during hepatic wound healing. PLoS One 2013; 8:e77166. [PMID: 24204762 PMCID: PMC3812165 DOI: 10.1371/journal.pone.0077166] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 08/30/2013] [Indexed: 01/18/2023] Open
Abstract
Smooth muscle α actin (Acta2) expression is largely restricted to smooth muscle cells, pericytes and specialized fibroblasts, known as myofibroblasts. Liver injury, associated with cirrhosis, induces transformation of resident hepatic stellate cells into liver specific myofibroblasts, also known as activated cells. Here, we have used in vitro and in vivo wound healing models to explore the functional role of Acta2 in this transformation. Acta2 was abundant in activated cells isolated from injured livers but was undetectable in quiescent cells isolated from normal livers. Both cellular motility and contraction were dramatically increased in injured liver cells, paralleled by an increase in Acta2 expression, when compared with quiescent cells. Inhibition of Acta2 using several different techniques had no effect on cytoplasmic actin isoform expression, but led to reduced cellular motility and contraction. Additionally, Acta2 knockdown was associated with a significant reduction in Erk1/2 phosphorylation compared to control cells. The data indicate that Acta2 is important specifically in myofibroblast cell motility and contraction and raise the possibility that the Acta2 cytoskeleton, beyond its structural importance in the cell, could be important in regulating signaling processes during wound healing in vivo.
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Affiliation(s)
- Don C. Rockey
- Department of Internal Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
- * E-mail:
| | - Nate Weymouth
- Division of Digestive and Liver Diseases, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Zengdun Shi
- Department of Internal Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
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45
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Gomes AC, Falcão-Pires I, Pires AL, Brás-Silva C, Leite-Moreira AF. Rodent models of heart failure: an updated review. Heart Fail Rev 2013; 18:219-49. [PMID: 22446984 DOI: 10.1007/s10741-012-9305-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Heart failure (HF) is one of the major health and economic burdens worldwide, and its prevalence is continuously increasing. The study of HF requires reliable animal models to study the chronic changes and pharmacologic interventions in myocardial structure and function and to follow its progression toward HF. Indeed, during the past 40 years, basic and translational scientists have used small animal models to understand the pathophysiology of HF and find more efficient ways of preventing and managing patients suffering from congestive HF (CHF). Each species and each animal model has advantages and disadvantages, and the choice of one model over another should take them into account for a good experimental design. The aim of this review is to describe and highlight the advantages and drawbacks of some commonly used HF rodents models, including both non-genetically and genetically engineered models, with a specific subchapter concerning diastolic HF models.
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Affiliation(s)
- A C Gomes
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319, Porto, Portugal
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46
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Müller M, Diensthuber RP, Chizhov I, Claus P, Heissler SM, Preller M, Taft MH, Manstein DJ. Distinct functional interactions between actin isoforms and nonsarcomeric myosins. PLoS One 2013; 8:e70636. [PMID: 23923011 PMCID: PMC3724804 DOI: 10.1371/journal.pone.0070636] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 06/26/2013] [Indexed: 02/07/2023] Open
Abstract
Despite their near sequence identity, actin isoforms cannot completely replace each other in vivo and show marked differences in their tissue-specific and subcellular localization. Little is known about isoform-specific differences in their interactions with myosin motors and other actin-binding proteins. Mammalian cytoplasmic β- and γ-actin interact with nonsarcomeric conventional myosins such as the members of the nonmuscle myosin-2 family and myosin-7A. These interactions support a wide range of cellular processes including cytokinesis, maintenance of cell polarity, cell adhesion, migration, and mechano-electrical transduction. To elucidate differences in the ability of isoactins to bind and stimulate the enzymatic activity of individual myosin isoforms, we characterized the interactions of human skeletal muscle α-actin, cytoplasmic β-actin, and cytoplasmic γ-actin with human myosin-7A and nonmuscle myosins-2A, -2B and -2C1. In the case of nonmuscle myosins-2A and -2B, the interaction with either cytoplasmic actin isoform results in 4-fold greater stimulation of myosin ATPase activity than was observed in the presence of α-skeletal muscle actin. Nonmuscle myosin-2C1 is most potently activated by β-actin and myosin-7A by γ-actin. Our results indicate that β- and γ-actin isoforms contribute to the modulation of nonmuscle myosin-2 and myosin-7A activity and thereby to the spatial and temporal regulation of cytoskeletal dynamics. FRET-based analyses show efficient copolymerization abilities for the actin isoforms in vitro. Experiments with hybrid actin filaments show that the extent of actomyosin coupling efficiency can be regulated by the isoform composition of actin filaments.
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Affiliation(s)
- Mirco Müller
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | | | - Igor Chizhov
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Peter Claus
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Sarah M. Heissler
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Matthias Preller
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Manuel H. Taft
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Dietmar J. Manstein
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
- * E-mail:
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47
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Sequeira V, Nijenkamp LLAM, Regan JA, van der Velden J. The physiological role of cardiac cytoskeleton and its alterations in heart failure. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:700-22. [PMID: 23860255 DOI: 10.1016/j.bbamem.2013.07.011] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 07/01/2013] [Accepted: 07/08/2013] [Indexed: 12/11/2022]
Abstract
Cardiac muscle cells are equipped with specialized biochemical machineries for the rapid generation of force and movement central to the work generated by the heart. During each heart beat cardiac muscle cells perceive and experience changes in length and load, which reflect one of the fundamental principles of physiology known as the Frank-Starling law of the heart. Cardiac muscle cells are unique mechanical stretch sensors that allow the heart to increase cardiac output, and adjust it to new physiological and pathological situations. In the present review we discuss the mechano-sensory role of the cytoskeletal proteins with respect to their tight interaction with the sarcolemma and extracellular matrix. The role of contractile thick and thin filament proteins, the elastic protein titin, and their anchorage at the Z-disc and M-band, with associated proteins are reviewed in physiologic and pathologic conditions leading to heart failure. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé
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Affiliation(s)
- Vasco Sequeira
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
| | - Louise L A M Nijenkamp
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
| | - Jessica A Regan
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands; Department of Physiology, Molecular Cardiovascular Research Program, Sarver Heart Center, University of Arizona, Tucson, AZ 85724, USA
| | - Jolanda van der Velden
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands; ICIN-Netherlands Heart Institute, The Netherlands.
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48
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Preuss C, Andelfinger G. Genetics of Heart Failure in Congenital Heart Disease. Can J Cardiol 2013; 29:803-10. [DOI: 10.1016/j.cjca.2013.03.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 02/27/2013] [Accepted: 03/06/2013] [Indexed: 01/09/2023] Open
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49
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Tondeleir D, Drogat B, Slowicka K, Bakkali K, Bartunkova S, Goossens S, Haigh JJ, Ampe C. Beta-Actin Is Involved in Modulating Erythropoiesis during Development by Fine-Tuning Gata2 Expression Levels. PLoS One 2013; 8:e67855. [PMID: 23840778 PMCID: PMC3694046 DOI: 10.1371/journal.pone.0067855] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 05/28/2013] [Indexed: 12/22/2022] Open
Abstract
The functions of actin family members during development are poorly understood. To investigate the role of beta-actin in mammalian development, a beta-actin knockout mouse model was used. Homozygous beta-actin knockout mice are lethal at embryonic day (E)10.5. At E10.25 beta-actin knockout embryos are growth retarded and display a pale yolk sac and embryo proper that is suggestive of altered erythropoiesis. Here we report that lack of beta-actin resulted in a block of primitive and definitive hematopoietic development. Reduced levels of Gata2, were associated to this phenotype. Consistently, ChIP analysis revealed multiple binding sites for beta-actin in the Gata2 promoter. Gata2 mRNA levels were almost completely rescued by expression of an erythroid lineage restricted ROSA26-promotor based GATA2 transgene. As a result, erythroid differentiation was restored and the knockout embryos showed significant improvement in yolk sac and embryo vascularization. These results provide new molecular insights for a novel function of beta-actin in erythropoiesis by modulating the expression levels of Gata2 in vivo.
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Affiliation(s)
- Davina Tondeleir
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Benjamin Drogat
- Vascular Cell Biology Unit, Department for Molecular Biomedical Research, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Karolina Slowicka
- Vascular Cell Biology Unit, Department for Molecular Biomedical Research, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Karima Bakkali
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Sonia Bartunkova
- Vascular Cell Biology Unit, Department for Molecular Biomedical Research, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Steven Goossens
- Vascular Cell Biology Unit, Department for Molecular Biomedical Research, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Jody J. Haigh
- Vascular Cell Biology Unit, Department for Molecular Biomedical Research, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- * E-mail: * (CA); (JJH)
| | - Christophe Ampe
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
- * E-mail: * (CA); (JJH)
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Ochala J, Iwamoto H, Ravenscroft G, Laing NG, Nowak KJ. Skeletal and cardiac α-actin isoforms differently modulate myosin cross-bridge formation and myofibre force production. Hum Mol Genet 2013; 22:4398-404. [PMID: 23784376 DOI: 10.1093/hmg/ddt289] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Multiple congenital myopathies, including nemaline myopathy, can arise due to mutations in the ACTA1 gene encoding skeletal muscle α-actin. The main characteristics of ACTA1 null mutations (absence of skeletal muscle α-actin) are generalized skeletal muscle weakness and premature death. A mouse model (ACTC(Co)/KO) mimicking these conditions has successfully been rescued by transgenic over-expression of cardiac α-actin in skeletal muscles using the ACTC gene. Nevertheless, myofibres from ACTC(Co)/KO animals generate less force than normal myofibres (-20 to 25%). To understand the underlying mechanisms, here we have undertaken a detailed functional study of myofibres from ACTC(Co)/KO rodents. Mechanical and X-ray diffraction pattern analyses of single membrane-permeabilized myofibres showed, upon maximal Ca(2+) activation and under rigor conditions, lower stiffness and disrupted actin-layer line reflections in ACTC(Co)/KO when compared with age-matched wild-types. These results demonstrate that in ACTC(Co)/KO myofibres, the presence of cardiac α-actin instead of skeletal muscle α-actin alters actin conformational changes upon activation. This later finely modulates the strain of individual actomyosin interactions and overall lowers myofibre force production. Taken together, the present findings provide novel primordial information about actin isoforms, their functional differences and have to be considered when designing gene therapies for ACTA1-based congenital myopathies.
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Affiliation(s)
- Julien Ochala
- Centre of Human and Aerospace Physiological Sciences, School of Biomedical Sciences, King's College London, Room 3.3, Shepherd's House, Guy's Campus, London SE1 1UL, UK
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