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[PMID]:28470530
[Au] Autor:Buttgereit A
[Ad] Endereço:Institute of Medical Biotechnology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany. Andreas.Buttgereit@t-online.de.
[Ti] Título:Second Harmonic Generation Microscopy of Muscle Cell Morphology and Dynamics.
[So] Source:Methods Mol Biol;1601:229-241, 2017.
[Is] ISSN:1940-6029
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Microscopy in combination with contrast-increasing dyes allows the visualization and analysis of organs, tissues, and various cells. Because of their better resolution, the development of confocal and laser microscopes enables the investigations of cell components, which are labeled with fluorescent dyes. The imaging of living cells on subcellular level (also in vivo) needs a labeling by gene transfection of GFP or similar labeled proteins. We present a method for visualization of cell structure in skeletal and heart muscle by label-free Second Harmonic Generation (SHG) microscopy and describe analytic methods for quantitative measurements of morphology and dynamics in skeletal muscle fibers.
[Mh] Termos MeSH primário: Fibras Musculares Esqueléticas/ultraestrutura
Miócitos Cardíacos/ultraestrutura
Microscopia de Geração do Segundo Harmônico/métodos
[Mh] Termos MeSH secundário: Animais
Corantes Fluorescentes/química
Proteínas de Fluorescência Verde/química
Imagem Tridimensional
Microscopia Confocal
Fibras Musculares Esqueléticas/química
Miócitos Cardíacos/química
Miosinas/química
Fótons
Sarcômeros/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Fluorescent Dyes); 147336-22-9 (Green Fluorescent Proteins); EC 3.6.4.1 (Myosins)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180219
[Lr] Data última revisão:
180219
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170505
[St] Status:MEDLINE
[do] DOI:10.1007/978-1-4939-6960-9_18


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[PMID]:29331378
[Au] Autor:Paone C; Rudeck S; Etard C; Strähle U; Rottbauer W; Just S
[Ad] Endereço:Molecular Cardiology, Department of Inner Medicine II, University of Ulm, Ulm, Germany.
[Ti] Título:Loss of zebrafish Smyd1a interferes with myofibrillar integrity without triggering the misfolded myosin response.
[So] Source:Biochem Biophys Res Commun;496(2):339-345, 2018 02 05.
[Is] ISSN:1090-2104
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Sarcomeric protein turnover needs to be tightly balanced to assure proper assembly and renewal of sarcomeric units within muscle tissues. The mechanisms regulating these fundamental processes are only poorly understood, but of great clinical importance since many cardiac and skeletal muscle diseases are associated with defective sarcomeric organization. The SET- and MYND domain containing protein 1b (Smyd1b) is known to play a crucial role in myofibrillogenesis by functionally interacting with the myosin chaperones Unc45b and Hsp90α1. In zebrafish, Smyd1b, Unc45b and Hsp90α1 are part of the misfolded myosin response (MMR), a regulatory transcriptional response that is activated by disturbed myosin homeostasis. Genome duplication in zebrafish led to a second smyd1 gene, termed smyd1a. Morpholino- and CRISPR/Cas9-mediated knockdown of smyd1a led to significant perturbations in sarcomere structure resulting in decreased cardiac as well as skeletal muscle function. Similar to Smyd1b, we found Smyd1a to localize to the sarcomeric M-band in skeletal and cardiac muscles. Overexpression of smyd1a efficiently compensated for the loss of Smyd1b in flatline (fla) mutant zebrafish embryos, rescued the myopathic phenotype and suppressed the MMR in Smyd1b-deficient embryos, suggesting overlapping functions of both Smyd1 paralogs. Interestingly, Smyd1a is not transcriptionally activated in Smyd1b-deficient fla mutants, demonstrating lack of genetic compensation despite the functional redundancy of both zebrafish Smyd1 paralogs.
[Mh] Termos MeSH primário: Regulação da Expressão Gênica no Desenvolvimento
Histona-Lisina N-Metiltransferase/genética
Músculo Esquelético/metabolismo
Miócitos Cardíacos/metabolismo
Miosinas/genética
Sarcômeros/metabolismo
Proteínas de Peixe-Zebra/genética
Peixe-Zebra/genética
[Mh] Termos MeSH secundário: Animais
Animais Geneticamente Modificados
Sistemas CRISPR-Cas
Embrião não Mamífero
Duplicação Gênica
Edição de Genes
Genes Reporter
Proteínas de Fluorescência Verde/genética
Proteínas de Fluorescência Verde/metabolismo
Proteínas de Choque Térmico HSP90/genética
Proteínas de Choque Térmico HSP90/metabolismo
Histona-Lisina N-Metiltransferase/antagonistas & inibidores
Histona-Lisina N-Metiltransferase/deficiência
Seres Humanos
Chaperonas Moleculares/genética
Chaperonas Moleculares/metabolismo
Morfolinos/genética
Morfolinos/metabolismo
Músculo Esquelético/patologia
Miócitos Cardíacos/patologia
Miosinas/metabolismo
Dobramento de Proteína
Isoformas de Proteínas/deficiência
Isoformas de Proteínas/genética
Sarcômeros/patologia
Peixe-Zebra/crescimento & desenvolvimento
Peixe-Zebra/metabolismo
Proteínas de Peixe-Zebra/antagonistas & inibidores
Proteínas de Peixe-Zebra/deficiência
Proteínas de Peixe-Zebra/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (HSP90 Heat-Shock Proteins); 0 (Molecular Chaperones); 0 (Morpholinos); 0 (Protein Isoforms); 0 (Unc45b protein, zebrafish); 0 (Zebrafish Proteins); 147336-22-9 (Green Fluorescent Proteins); EC 2.1.1.43 (Histone-Lysine N-Methyltransferase); EC 2.1.1.43 (SmyD1 protein, zebrafish); EC 3.6.4.1 (Myosins)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180214
[Lr] Data última revisão:
180214
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180115
[St] Status:MEDLINE


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[PMID]:28463291
[Au] Autor:Abdelsalam DG; Yasui T
[Ti] Título:High brightness, low coherence, digital holographic microscopy for 3D visualization of an in-vitro sandwiched biological sample.
[So] Source:Appl Opt;56(13):F1-F6, 2017 May 01.
[Is] ISSN:1539-4522
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:We achieve practically a bright-field digital holographic microscopy (DHM) configuration free from coherent noise for three-dimensional (3D) visualization of an in-vitro sandwiched sarcomere sample. Visualization of such sandwiched samples by conventional atomic force microscope (AFM) is impossible, while visualization using DHM with long coherent lengths is challenging. The proposed configuration is comprised of an ultrashort pulse laser source and a Mach-Zehnder interferometer in transmission. Periodically poled lithium niobate (PPLN) crystal was used to convert the fundamental beam by second harmonic generation (SHG) to the generated beam fit to the CCD camera used. The experimental results show that the contrast of the reconstructed phase image is improved to a higher degree compared to a He-Ne laser based result. We attribute this improvement to two things: the feature of the femtosecond pulse light, which acts as a chopper for coherent noise suppression, and the fact that the variance of a coherent mode can be reduced by a factor of 9 due to low loss through a nonlinear medium.
[Mh] Termos MeSH primário: Holografia/métodos
Imagem Tridimensional/métodos
Lasers
Microscopia de Interferência
Sarcômeros
[Mh] Termos MeSH secundário: Cristalização
Desenho de Equipamento
Aumento da Imagem/instrumentação
Aumento da Imagem/métodos
Interpretação de Imagem Assistida por Computador/métodos
Técnicas In Vitro
Interferometria
Nióbio
Óxidos
Sarcômeros/ultraestrutura
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Oxides); 05175J654G (Niobium); 12031-63-9 (lithium niobate)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180206
[Lr] Data última revisão:
180206
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE
[do] DOI:10.1364/AO.56.0000F1


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[PMID]:28465030
[Au] Autor:Bayoglu R; Geeraedts L; Groenen KHJ; Verdonschot N; Koopman B; Homminga J
[Ad] Endereço:Department of Biomechanical Engineering, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. Electronic address: r.bayoglu@hotmail.com.
[Ti] Título:Twente spine model: A complete and coherent dataset for musculo-skeletal modeling of the thoracic and cervical regions of the human spine.
[So] Source:J Biomech;58:52-63, 2017 06 14.
[Is] ISSN:1873-2380
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Musculo-skeletal modeling could play a key role in advancing our understanding of the healthy and pathological spine, but the credibility of such models are strictly dependent on the accuracy of the anatomical data incorporated. In this study, we present a complete and coherent musculo-skeletal dataset for the thoracic and cervical regions of the human spine, obtained through detailed dissection of an embalmed male cadaver. We divided the muscles into a number of muscle-tendon elements, digitized their attachments at the bones, and measured morphological muscle parameters. In total, 225 muscle elements were measured over 39 muscles. For every muscle element, we provide the coordinates of its attachments, fiber length, tendon length, sarcomere length, optimal fiber length, pennation angle, mass, and physiological cross-sectional area together with the skeletal geometry of the cadaver. Results were consistent with similar anatomical studies. Furthermore, we report new data for several muscles such as rotatores, multifidus, levatores costarum, spinalis, semispinalis, subcostales, transversus thoracis, and intercostales muscles. This dataset complements our previous study where we presented a consistent dataset for the lumbar region of the spine (Bayoglu et al., 2017). Therefore, when used together, these datasets enable a complete and coherent dataset for the entire spine. The complete dataset will be used to develop a musculo-skeletal model for the entire human spine to study clinical and ergonomic applications.
[Mh] Termos MeSH primário: Vértebras Cervicais/anatomia & histologia
Modelos Anatômicos
Músculo Esquelético/anatomia & histologia
Vértebras Torácicas/anatomia & histologia
[Mh] Termos MeSH secundário: Idoso
Seres Humanos
Masculino
Sarcômeros
Tendões/anatomia & histologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1711
[Cu] Atualização por classe:180120
[Lr] Data última revisão:
180120
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170504
[St] Status:MEDLINE


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[PMID]:29262369
[Au] Autor:Shalabi N; Persson M; Månsson A; Vengallatore S; Rassier DE
[Ad] Endereço:Department of Mechanical Engineering, McGill University, Montreal, Québec, Canada; Department of Kinesiology and Physical Education, McGill University, Montreal, Québec, Canada.
[Ti] Título:Sarcomere Stiffness during Stretching and Shortening of Rigor Skeletal Myofibrils.
[So] Source:Biophys J;113(12):2768-2776, 2017 Dec 19.
[Is] ISSN:1542-0086
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:In this study, we measured the stiffness of skeletal muscle myofibrils in rigor. Using a custom-built atomic force microscope, myofibrils were first placed in a rigor state then stretched and shortened at different displacements (0.1-0.3 µm per sarcomere) and nominal speeds (0.4 and 0.8 µm/s). During stretching, the myofibril stiffness was independent of both displacement and speed (average of 987 nN/µm). During shortening, the myofibril stiffness was independent of displacement, but dependent on speed (1234 nN/µm at 0.4 µm/s; 1106 nN/µm at 0.8 µm/s). Furthermore, the myofibril stiffness during shortening was greater than that during stretching and the difference depended on speed (31% at 0.4 µm/s; 8% at 0.8 µm/s). The results suggest that the myofibrils exhibit nonlinear viscoelastic properties that may be derived from myofibril filaments, similar to what has been observed in muscle fibers.
[Mh] Termos MeSH primário: Fenômenos Mecânicos
Sarcômeros/metabolismo
[Mh] Termos MeSH secundário: Animais
Fenômenos Biomecânicos
Proteínas do Citoesqueleto/metabolismo
Feminino
Microscopia de Força Atômica
Coelhos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Cytoskeletal Proteins)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180102
[Lr] Data última revisão:
180102
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171221
[St] Status:MEDLINE


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[PMID]:27773487
[Au] Autor:Coravos JS; Martin AC
[Ad] Endereço:Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02142, USA.
[Ti] Título:Apical Sarcomere-like Actomyosin Contracts Nonmuscle Drosophila Epithelial Cells.
[So] Source:Dev Cell;39(3):346-358, 2016 11 07.
[Is] ISSN:1878-1551
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Actomyosin networks generate contractile force that changes cell and tissue shape. In muscle cells, actin filaments and myosin II appear in a polarized structure called a sarcomere, in which myosin II is localized in the center. Nonmuscle cortical actomyosin networks are thought to contract when nonmuscle myosin II (myosin) is activated throughout a mixed-polarity actin network. Here, we identified a mutant version of the myosin-activating kinase, ROCK, that localizes diffusely, rather than centrally, in epithelial cell apices. Surprisingly, this mutant inhibits constriction, suggesting that centrally localized apical ROCK/myosin activity promotes contraction. We determined actin cytoskeletal polarity by developing a barbed end incorporation assay for Drosophila embryos, which revealed barbed end enrichment at junctions. Our results demonstrate that epithelial cells contract with a spatially organized apical actomyosin cortex, involving a polarized actin cytoskeleton and centrally positioned myosin, with cell-scale order that resembles a muscle sarcomere.
[Mh] Termos MeSH primário: Actomiosina/metabolismo
Polaridade Celular
Células Epiteliais/citologia
Contração Muscular
Músculos/citologia
[Mh] Termos MeSH secundário: Citoesqueleto de Actina/metabolismo
Actinas/metabolismo
Animais
Forma Celular
Proteínas de Drosophila/metabolismo
Drosophila melanogaster/citologia
Drosophila melanogaster/embriologia
Células Epiteliais/metabolismo
Modelos Biológicos
Morfogênese
Miosina Tipo II/metabolismo
Sarcômeros/metabolismo
Quinases Associadas a rho/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Actins); 0 (Drosophila Proteins); 9013-26-7 (Actomyosin); EC 2.7.11.1 (rho-Associated Kinases); EC 3.6.1.- (Myosin Type II)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:171207
[Lr] Data última revisão:
171207
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161025
[St] Status:MEDLINE


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[PMID]:29050564
[Au] Autor:Thorolfsdottir RB; Sveinbjornsson G; Sulem P; Helgadottir A; Gretarsdottir S; Benonisdottir S; Magnusdottir A; Davidsson OB; Rajamani S; Roden DM; Darbar D; Pedersen TR; Sabatine MS; Jonsdottir I; Arnar DO; Thorsteinsdottir U; Gudbjartsson DF; Holm H; Stefansson K
[Ad] Endereço:deCODE genetics/Amgen, Inc., Reykjavik, Iceland. Electronic address: rosath@decode.is.
[Ti] Título:A Missense Variant in PLEC Increases Risk of Atrial Fibrillation.
[So] Source:J Am Coll Cardiol;70(17):2157-2168, 2017 Oct 24.
[Is] ISSN:1558-3597
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Genome-wide association studies (GWAS) have yielded variants at >30 loci that associate with atrial fibrillation (AF), including rare coding mutations in the sarcomere genes MYH6 and MYL4. OBJECTIVES: The aim of this study was to search for novel AF associations and in doing so gain insights into the mechanisms whereby variants affect AF risk, using electrocardiogram (ECG) measurements. METHODS: The authors performed a GWAS of 14,255 AF cases and 374,939 controls, using whole-genome sequence data from the Icelandic population, and tested novel signals in 2,002 non-Icelandic cases and 12,324 controls. They then tested the AF variants for effect on cardiac electrical function by using measurements in 289,297 ECGs from 62,974 individuals. RESULTS: The authors discovered 2 novel AF variants, the intergenic variant rs72700114, between the genes LINC01142 and METTL11B (risk allele frequency = 8.1%; odds ratio [OR]: 1.26; p = 3.1 × 10 ), and the missense variant p.Gly4098Ser in PLEC (frequency = 1.2%; OR: 1.55; p = 8.0 × 10 ), encoding plectin, a cytoskeletal cross-linking protein that contributes to integrity of cardiac tissue. The authors also confirmed 29 reported variants. p.Gly4098Ser in PLEC significantly affects various ECG measurements in the absence of AF. Other AF variants have diverse effects on the conduction system, ranging from none to extensive. CONCLUSIONS: The discovery of a missense variant in PLEC affecting AF combined with recent discoveries of variants in the sarcomere genes MYH6 and MYL4 points to an important role of myocardial structure in the pathogenesis of the disease. The diverse associations between AF variants and ECG measurements suggest fundamentally different categories of mechanisms contributing to the development of AF.
[Mh] Termos MeSH primário: Fibrilação Atrial/genética
Variação Estrutural do Genoma
[Mh] Termos MeSH secundário: Fibrilação Atrial/fisiopatologia
Eletrocardiografia
Estudo de Associação Genômica Ampla
Seres Humanos
Mutação de Sentido Incorreto/genética
Cadeias Leves de Miosina/genética
Plectina/genética
Risco
Sarcômeros
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Myosin Light Chains); 0 (Plectin); 0 (myosin light chain 4, human)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171117
[Lr] Data última revisão:
171117
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:171021
[St] Status:MEDLINE


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[PMID]:29030372
[Au] Autor:Mamidi R; Li J; Gresham KS; Verma S; Doh CY; Li A; Lal S; Dos Remedios CG; Stelzer JE
[Ad] Endereço:From the Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH (R.M., J.L., C.Y.D., J.E.S.); Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA (K.S.G); Department of Horticulture Sciences, IFAS,
[Ti] Título:Dose-Dependent Effects of the Myosin Activator Omecamtiv Mecarbil on Cross-Bridge Behavior and Force Generation in Failing Human Myocardium.
[So] Source:Circ Heart Fail;10(10), 2017 Oct.
[Is] ISSN:1941-3297
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Omecamtiv mecarbil (OM) enhances systolic function in vivo by directly binding the myosin cross-bridges (XBs) in the sarcomere. However, the mechanistic details governing OM-induced modulation of XB behavior in failing human myocardium are unclear. METHODS AND RESULTS: The effects of OM on steady state and dynamic XB behavior were measured in chemically skinned myocardial preparations isolated from human donor and heart failure (HF) left ventricle. HF myocardium exhibited impaired contractile function as evidenced by reduced maximal force, magnitude of XB recruitment ( ), and a slowed rate of XB detachment ( ) at submaximal Ca activations. Ca sensitivity of force generation (pCa ) was higher in HF myocardium when compared with donor myocardium, both prior to and after OM incubations. OM incubation (0.5 and 1.0 µmol/L) enhanced force generation at submaximal Ca activations in a dose-dependent manner. Notably, OM induced a slowing in with 1.0 µmol/L OM but not with 0.5 µmol/L OM in HF myocardium. Additionally, OM exerted other differential effects on XB behavior in HF myocardium as evidenced by a greater enhancement in and slowing in the time course of cooperative XB recruitment ( ), which collectively prolonged achievement of peak force development ( ), compared with donor myocardium. CONCLUSIONS: Our findings demonstrate that OM augments force generation but also prolongs the time course of XB transitions to force-bearing states in remodeled HF myocardium, which may extend the systolic ejection time in vivo. Optimal OM dosing is critical for eliciting enhanced systolic function without excessive prolongation of systolic ejection time, which may compromise diastolic filling.
[Mh] Termos MeSH primário: Cardiotônicos/farmacologia
Insuficiência Cardíaca/tratamento farmacológico
Força Muscular/efeitos dos fármacos
Contração Miocárdica/efeitos dos fármacos
Miosinas/metabolismo
Ureia/análogos & derivados
[Mh] Termos MeSH secundário: Cardiotônicos/metabolismo
Proteínas de Transporte/metabolismo
Estudos de Casos e Controles
Relação Dose-Resposta a Droga
Insuficiência Cardíaca/metabolismo
Insuficiência Cardíaca/fisiopatologia
Seres Humanos
Técnicas In Vitro
Fosforilação
Ligação Proteica
Sarcômeros/metabolismo
Transdução de Sinais/efeitos dos fármacos
Fatores de Tempo
Troponina I/metabolismo
Troponina T/metabolismo
Ureia/metabolismo
Ureia/farmacologia
Remodelação Ventricular
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Cardiotonic Agents); 0 (Carrier Proteins); 0 (Troponin I); 0 (Troponin T); 0 (myosin-binding protein C); 2M19539ERK (omecamtiv mecarbil); 8W8T17847W (Urea); EC 3.6.4.1 (Myosins)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171015
[St] Status:MEDLINE


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[PMID]:29025768
[Au] Autor:Sirish P; Ledford HA; Timofeyev V; Thai PN; Ren L; Kim HJ; Park S; Lee JH; Dai G; Moshref M; Sihn CR; Chen WC; Timofeyeva MV; Jian Z; Shimkunas R; Izu LT; Chiamvimonvat N; Chen-Izu Y; Yamoah EN; Zhang XD
[Ad] Endereço:From the Division of Cardiovascular Medicine, Department of Internal Medicine (P.S., H.A.L., V.T., P.N.T., L.R., S.P., G.D., M.M., C.-R.S., W.C.C., M.V.T., N.C., Y.C.-I., X.-D.Z.), Center for Neuroscience (H.J.K.), Department of Pharmacology (Z.J., R.S., L.T.I., N.C., Y.C.-I.) and Department of Biom
[Ti] Título:Action Potential Shortening and Impairment of Cardiac Function by Ablation of .
[So] Source:Circ Arrhythm Electrophysiol;10(10), 2017 Oct.
[Is] ISSN:1941-3084
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Intracellular pH (pH ) is critical to cardiac excitation and contraction; uncompensated changes in pH impair cardiac function and trigger arrhythmia. Several ion transporters participate in cardiac pH regulation. Our previous studies identified several isoforms of a solute carrier Slc26a6 to be highly expressed in cardiomyocytes. We show that Slc26a6 mediates electrogenic Cl /HCO exchange activities in cardiomyocytes, suggesting the potential role of Slc26a6 in regulation of not only pH , but also cardiac excitability. METHODS AND RESULTS: To test the mechanistic role of Slc26a6 in the heart, we took advantage of knockout ( ) mice using both in vivo and in vitro analyses. Consistent with our prediction of its electrogenic activities, ablation of results in action potential shortening. There are reduced Ca transient and sarcoplasmic reticulum Ca load, together with decreased sarcomere shortening in cardiomyocytes. These abnormalities translate into reduced fractional shortening and cardiac contractility at the in vivo level. Additionally, pH is elevated in cardiomyocytes with slower recovery kinetics from intracellular alkalization, consistent with the Cl /HCO exchange activities of Slc26a6. Moreover, mice show evidence of sinus bradycardia and fragmented QRS complex, supporting the critical role of Slc26a6 in cardiac conduction system. CONCLUSIONS: Our study provides mechanistic insights into Slc26a6, a unique cardiac electrogenic Cl /HCO transporter in ventricular myocytes, linking the critical roles of Slc26a6 in regulation of pH , excitability, and contractility. pH is a critical regulator of other membrane and contractile proteins. Future studies are needed to investigate possible changes in these proteins in mice.
[Mh] Termos MeSH primário: Potenciais de Ação
Antiporters/deficiência
Acoplamento Excitação-Contração
Frequência Cardíaca
Contração Miocárdica
Miócitos Cardíacos/metabolismo
[Mh] Termos MeSH secundário: Animais
Antiporters/genética
Bradicardia/genética
Bradicardia/metabolismo
Bradicardia/fisiopatologia
Células CHO
Cricetulus
Genótipo
Concentração de Íons de Hidrogênio
Cinética
Proteínas de Membrana Transportadoras/genética
Proteínas de Membrana Transportadoras/metabolismo
Camundongos da Linhagem 129
Camundongos Knockout
Fenótipo
Sarcômeros/metabolismo
Retículo Sarcoplasmático/metabolismo
Transfecção
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Antiporters); 0 (Membrane Transport Proteins); 0 (SLC26A6 protein, human); 0 (Slc26a6 protein, mouse)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171101
[Lr] Data última revisão:
171101
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171014
[St] Status:MEDLINE


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[PMID]:28867488
[Au] Autor:Bonnet A; Lambert G; Ernest S; Dutrieux FX; Coulpier F; Lemoine S; Lobbardi R; Rosa FM
[Ad] Endereço:IBENS, Institut de Biologie de l'Ecole Normale Supérieure, 75005 Paris, France; INSERM U1024, 75005 Paris, France; CNRS UMR 8197, 75005 Paris, France. Electronic address: bonnet.aline@gmail.com.
[Ti] Título:Quaking RNA-Binding Proteins Control Early Myofibril Formation by Modulating Tropomyosin.
[So] Source:Dev Cell;42(5):527-541.e4, 2017 Sep 11.
[Is] ISSN:1878-1551
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Skeletal muscle contraction is mediated by myofibrils, complex multi-molecular scaffolds structured into repeated units, the sarcomeres. Myofibril structure and function have been extensively studied, but the molecular processes regulating its formation within the differentiating muscle cell remain largely unknown. Here we show in zebrafish that genetic interference with the Quaking RNA-binding proteins disrupts the initial steps of myofibril assembly without affecting early muscle differentiation. Using RNA sequencing, we demonstrate that Quaking is required for accumulation of the muscle-specific tropomyosin-3 transcript, tpm3.12. Further functional analyses reveal that Tpm3.12 mediates Quaking control of myofibril formation. Moreover, we identified a Quaking-binding site in the 3' UTR of tpm3.12 transcript, which is required in vivo for tpm3.12 accumulation and myofibril formation. Our work uncovers a Quaking/Tpm3 pathway controlling de novo myofibril assembly. This unexpected developmental role for Tpm3 could be at the origin of muscle defects observed in human congenital myopathies associated with tpm3 mutation.
[Mh] Termos MeSH primário: Miofibrilas/metabolismo
Proteínas de Ligação a RNA/metabolismo
Tropomiosina/metabolismo
Proteínas de Peixe-Zebra/metabolismo
Peixe-Zebra/metabolismo
[Mh] Termos MeSH secundário: Regiões 3' não Traduzidas/genética
Animais
Sítios de Ligação
Diferenciação Celular/genética
Desenvolvimento Embrionário/genética
Regulação da Expressão Gênica no Desenvolvimento
Células Musculares/citologia
Células Musculares/metabolismo
Desenvolvimento Muscular/genética
Miosinas/metabolismo
RNA Mensageiro/genética
RNA Mensageiro/metabolismo
Sarcômeros/metabolismo
Somitos/embriologia
Somitos/metabolismo
Peixe-Zebra/embriologia
Peixe-Zebra/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (3' Untranslated Regions); 0 (RNA, Messenger); 0 (RNA-Binding Proteins); 0 (Tropomyosin); 0 (Zebrafish Proteins); 0 (qk protein, zebrafish); EC 3.6.4.1 (Myosins)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170925
[Lr] Data última revisão:
170925
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170905
[St] Status:MEDLINE



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