المؤلفون: Zhaoning Wang, Eric N. Olson, Rhonda Bassel-Duby, Hui Li, Francesco Chemello, Ning Liu, John R. McAnally

المصدر: Proc Natl Acad Sci U S A

مصطلحات موضوعية: musculoskeletal diseases, congenital, hereditary, and neonatal diseases and abnormalities, Cell type, Transcription, Genetic, Duchenne muscular dystrophy, Muscle disorder, Dystrophin, Macular Degeneration, Mice, Exon, Multinucleate, Myofibrils, Commentaries, medicine, Animals, Regeneration, Humans, Myocyte, Gene Regulatory Networks, Muscle, Skeletal, Multidisciplinary, biology, Sequence Analysis, RNA, Skeletal muscle, Exons, Muscular Dystrophy, Animal, Biological Sciences, medicine.disease, Cell biology, Mice, Inbred C57BL, Muscular Dystrophy, Duchenne, Disease Models, Animal, medicine.anatomical_structure, Mutation, biology.protein, Transcriptome, Gene Deletion, Signal Transduction

الوصف: Duchenne muscular dystrophy (DMD) is a fatal muscle disorder characterized by cycles of degeneration and regeneration of multinucleated myofibers and pathological activation of a variety of other muscle-associated cell types. The extent to which different nuclei within the shared cytoplasm of a myofiber may display transcriptional diversity and whether individual nuclei within a multinucleated myofiber might respond differentially to DMD pathogenesis is unknown. Similarly, the potential transcriptional diversity among nonmuscle cell types within dystrophic muscle has not been explored. Here, we describe the creation of a mouse model of DMD caused by deletion of exon 51 of the dystrophin gene, which represents a prevalent disease-causing mutation in humans. To understand the transcriptional abnormalities and heterogeneity associated with myofiber nuclei, as well as other mononucleated cell types that contribute to the muscle pathology associated with DMD, we performed single-nucleus transcriptomics of skeletal muscle of mice with dystrophin exon 51 deletion. Our results reveal distinctive and previously unrecognized myonuclear subtypes within dystrophic myofibers and uncover degenerative and regenerative transcriptional pathways underlying DMD pathogenesis. Our findings provide insights into the molecular underpinnings of DMD, controlled by the transcriptional activity of different types of muscle and nonmuscle nuclei.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c5d1a93adf459f6ebc9eb7fa1c33c7c1Test
https://doi.org/10.1073/pnas.2018391117Test

المؤلفون: Gerard P. Sergeant, Keith D. Thornbury, Mark A. Hollywood

المصدر: Proceedings of the National Academy of Sciences. 117:32836-32838

مصطلحات موضوعية: 0301 basic medicine, BK channel, Multidisciplinary, biology, Depolarization, Iberiotoxin, urologic and male genital diseases, medicine.disease, female genital diseases and pregnancy complications, 03 medical and health sciences, Transient receptor potential channel, chemistry.chemical_compound, 030104 developmental biology, 0302 clinical medicine, Urethra, medicine.anatomical_structure, chemistry, Overactive bladder, biology.protein, Biophysics, medicine, Myocyte, Paxilline, 030217 neurology & neurosurgery

الوصف: Storage and voiding of urine in mammals is accomplished by a reciprocal contractile relationship between the bladder and the urethra. During the storage phase, the urethra remains contracted to prevent leakage of urine, while the bladder is relaxed to accommodate the increased volume of urine. Conversely, during voiding, the urethra relaxes, while the bladder contracts to generate an intravesical pressure which exceeds that in the urethra (1). The cellular mechanisms that govern these functions are only partly understood, and there is a particular paucity of data on the cellular processes that underlie tonic contraction of urethral smooth muscle (USM). This issue is addressed in PNAS by Griffin et al. (2), who demonstrate a critical role for transient receptor potential mucolipin 1 (TRPML1) channels in the regulation of detrusor and USM excitability. Spontaneous phasic contractions of the detrusor are directly correlated with bursts of action potentials, mediated by activation of voltage-dependent CaV1.2 channels (VDCC) (3). Selective blockade of large conductance Ca2+-activated K+ (BK) channels with iberiotoxin or paxilline induced depolarization and increased the amplitude and duration of spontaneous action potentials and phasic contractions (4). Furthermore, transgenic mice that lack the BK channel α subunit demonstrate a marked increase in urination frequency, corresponding to an overactive bladder (OAB) phenotype (5). This is thought to result from increased Ca2+ influx via VDCC as a result of diminished negative feedback, which limits Ca2+ entry. The BK channel blocker, penitrem A, increased the amplitude and duration of action potentials in USM cells (USMC) (6, 7), indicating that BK channels are also important regulators of USM excitability. The primary activation mechanism for BK channels in detrusor myocytes is localized Ca2+ release from intracellular stores, referred to as Ca2+ sparks (8). The resultant BK currents are termed … [↵][1]1To whom correspondence may be addressed. Email: gerard.sergeant{at}dkit.ie. [1]: #xref-corresp-1-1

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::13b6472eb3410ed5f102474574c0bd78Test
https://doi.org/10.1073/pnas.2022896117Test

المؤلفون: Benjamin M. Hogan, Angela Jeanes, Steven Petrou, Geza Berecki, Laurence Garric, Ophelia V. Ehrlich, Irina Vetter, Cas Simons, Teun P. de Boer, Charlotte D. Koopman, Samuel D. Robinson, Swati Iyer, Veronica Uribe, Scott Paterson, Jason Da Silva, Arie O. Verkerk, Gregory J. Baillie, Jessica E. De Angelis, Jeroen Bakkers, Kelly A. Smith

المساهمون: Hubrecht Institute for Developmental Biology and Stem Cell Research, Medical Biology, ACS - Amsterdam Cardiovascular Sciences

المصدر: Proceedings of the National Academy of Sciences of the United States of America, 118(9). National Academy of Sciences
Proceedings of the National Academy of Sciences of the United States of America, 118(9):e2018220118. National Academy of Sciences

مصطلحات موضوعية: Periodicity, Embryo, Nonmammalian, Mouse, Forward genetics, Arrhythmias, Lethal, Animals, Genetically Modified, Mice, Myocyte, Developmental, Arrhythmias, Cardiac/genetics, Zebrafish, Conserved Sequence, Mice, Knockout, Nonmammalian, Multidisciplinary, biology, Gene Expression Regulation, Developmental, Heart Rate/genetics, Myocytes, Cardiac/metabolism, Cell biology, Embryo, Action Potentials/genetics, Cardiac/metabolism, Knockout mouse, Haploinsufficiency, Cardiac, Arrhythmia, Cardiac function curve, Calcium/metabolism, Knockout, Potassium/metabolism, Genetically Modified, Cardiac/genetics, Zebrafish Proteins/genetics, Animals, Membrane Proteins/genetics, Myocytes, Ion Transport, Base Sequence, Organogenesis/genetics, Animal, Mammalian, Cardiac arrhythmia, Embryo, Mammalian, biology.organism_classification, Disease Models, Animal, Gene Expression Regulation, Genes, Disease Models, Mutation, Genes, Lethal, Heart/embryology, Genetic screen

الوصف: The establishment of cardiac function in the developing embryo is essential to ensure blood flow and, therefore, growth and survival of the animal. The molecular mechanisms controlling normal cardiac rhythm remain to be fully elucidated. From a forward genetic screen, we identified a unique mutant, grime, that displayed a specific cardiac arrhythmia phenotype. We show that loss-of-function mutations in tmem161b are responsible for the phenotype, identifying Tmem161b as a regulator of cardiac rhythm in zebrafish. To examine the evolutionary conservation of this function, we generated knockout mice for Tmem161b. Tmem161b knockout mice are neonatal lethal and cardiomyocytes exhibit arrhythmic calcium oscillations. Mechanistically, we find that Tmem161b is expressed at the cell membrane of excitable cells and live imaging shows it is required for action potential repolarization in the developing heart. Electrophysiology on isolated cardiomyocytes demonstrates that Tmem161b is essential to inhibit Ca2+ and K+ currents in cardiomyocytes. Importantly, Tmem161b haploinsufficiency leads to cardiac rhythm phenotypes, implicating it as a candidate gene in heritable cardiac arrhythmia. Overall, these data describe Tmem161b as a highly conserved regulator of cardiac rhythm that functions to modulate ion channel activity in zebrafish and mice.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ca136610721e5a7dc6a382d945333974Test
https://doi.org/10.1073/pnas.2018220118Test

المؤلفون: Karim Azzag, James A. Thomson, Ami Yamamoto, Michael Kyba, Ron Stewart, Tania Incitti, Alessandro Magli, Karena Lin, Robert W. Arpke, Rita C.R. Perlingeiro, Ce Yuan, Radbod Darabi

المصدر: Proceedings of the National Academy of Sciences. 116:4346-4351

مصطلحات موضوعية: Pluripotent Stem Cells, Multidisciplinary, Gene Expression Profiling, Regeneration (biology), PAX3, PAX7 Transcription Factor, Cell Differentiation, Biological Sciences, Biology, Muscle Development, musculoskeletal system, Embryonic stem cell, Cell biology, Myoblasts, Transplantation, Transcriptome, Mice, Animals, Myocyte, Progenitor cell, Muscle, Skeletal, Induced pluripotent stem cell, PAX3 Transcription Factor

الوصف: Optimal cell-based therapies for the treatment of muscle degenerative disorders should not only regenerate fibers but provide a quiescent satellite cell pool ensuring long-term maintenance and regeneration. Conditional expression of Pax3/Pax7 in differentiating pluripotent stem cells (PSCs) allows the generation of myogenic progenitors endowed with enhanced regenerative capacity. To identify the molecular determinants underlying their regenerative potential, we performed transcriptome analyses of these cells along with primary myogenic cells from several developmental stages. Here we show that in vitro-generated PSC-derived myogenic progenitors possess a molecular signature similar to embryonic/fetal myoblasts. However, compared with fetal myoblasts, following transplantation they show superior myofiber engraftment and ability to seed the satellite cell niche, respond to multiple reinjuries, and contribute to long-term regeneration. Upon engraftment, the transcriptome of reisolated Pax3/Pax7–induced PSC-derived myogenic progenitors changes toward a postnatal molecular signature, particularly in genes involved in extracellular matrix remodeling. These findings demonstrate that Pax3/Pax7–induced myogenic progenitors remodel their molecular signature and functionally mature upon in vivo exposure to the adult muscle environment.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::185e553d3d22ba26dd37ca7dc2b4017bTest
https://doi.org/10.1073/pnas.1808303116Test

المؤلفون: Akane Ohta, Yohei Minakuchi, Atsushi Kuhara, Miki, Tomoyo Ujisawa, Atsushi Toyoda, Tatsuya

المصدر: Proceedings of the National Academy of Sciences. 115:8823-8828

مصطلحات موضوعية: 0301 basic medicine, Multidisciplinary, biology, Cell, Endoribonuclease, Thermoregulation, biology.organism_classification, Dorsal nerve cord, Cell biology, 03 medical and health sciences, Transient receptor potential channel, 030104 developmental biology, 0302 clinical medicine, medicine.anatomical_structure, medicine, biology.protein, Myocyte, 030217 neurology & neurosurgery, Caspase, Caenorhabditis elegans

الوصف: Significance Environmental temperature acclimation is essential to animal survival, yet thermoregulation mechanisms remain poorly understood. In this study, we describe Ca 2+ -dependent endoribonuclease (EndoU) ENDU-2 located in ADL chemosensory neurons and specific muscle cells as a regulator of multiple pleiotropic phenomena including cold tolerance, life span, and brood size through cell-autonomous and cell-nonautonomous pathways in nematode Caenorhabditis elegans . Ca 2+ imaging revealed ADL temperature response to be the result of transient receptor potential (TRP) channel activity and regulated by ENDU-2 via cell-autonomous and cell-nonautonomous pathways. Transcriptome analysis revealed that ENDU-2 influences expression of the caspase gene ced-3 . Moreover, ENDU-2 downregulates cold tolerance and synaptic remodeling in the dorsal nerve cord through caspase signaling. We therefore propose a model for cold tolerance regulation that occurs via EndoU action.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::1f64d4bb78165620f87a07d9cf4fa298Test
https://doi.org/10.1073/pnas.1808634115Test

المؤلفون: Eva A. Rog-Zielinska, Patrizia Camelliti, Urszula Siedlecka, Peter Kohl, Eileen T. O'Toole, T Knoepfel, Tommaso Poggioli, TA Quinn

المساهمون: Commission of the European Communities, British Heart Foundation

المصدر: Proceedings of the National Academy of Sciences. 113:14852-14857

مصطلحات موضوعية: Male, 0301 basic medicine, Action Potentials, Cell Count, Cell Communication, fibroblast, CARDIOMYOCYTES, Connexins, Membrane Potentials, Mice, Myocyte, Myocytes, Cardiac, IN-VIVO, heterocellular coupling, Membrane potential, Multidisciplinary, SINOATRIAL NODE, Gap junction, Gap Junctions, Heart, Biological Sciences, Multidisciplinary Sciences, medicine.anatomical_structure, CARDIAC ELECTRICAL-ACTIVITY, Science & Technology - Other Topics, Female, Electrical conduction system of the heart, CONTRIBUTE, EXPRESSION, FIBROBLASTS, cardiac, Mice, Transgenic, Biology, Optogenetics, MEMBRANE NANOTUBES, 03 medical and health sciences, ADULT, Bacterial Proteins, Heart Conduction System, ATRIAL, medicine, Animals, CONNECTIONS, Muscle Cells, Science & Technology, Sinoatrial node, Myocardium, Cell Membrane, Electric Conductivity, genetically-encoded voltage indicator, electrophysiology, FIBROBLAST-MYOCYTE INTERACTIONS, Coupling (electronics), Luminescent Proteins, Electrophysiology, 030104 developmental biology, CONDUCTION, TISSUE, Biophysics, Biomedical engineering

الوصف: Electrophysiological studies of excitable organs usually focus on action potential (AP)-generating cells, whereas nonexcitable cells are generally considered as barriers to electrical conduction. Whether nonexcitable cells may modulate excitable cell function or even contribute to AP conduction via direct electrotonic coupling to AP-generating cells is unresolved in the heart: such coupling is present in vitro, but conclusive evidence in situ is lacking. We used genetically encoded voltage-sensitive fluorescent protein 2.3 (VSFP2.3) to monitor transmembrane potential in either myocytes or nonmyocytes of murine hearts. We confirm that VSFP2.3 allows measurement of cell type-specific electrical activity. We show that VSFP2.3, expressed solely in nonmyocytes, can report cardiomyocyte AP-like signals at the border of healed cryoinjuries. Using EM-based tomographic reconstruction, we further discovered tunneling nanotube connections between myocytes and nonmyocytes in cardiac scar border tissue. Our results provide direct electrophysiological evidence of heterocellular electrotonic coupling in native myocardium and identify tunneling nanotubes as a possible substrate for electrical cell coupling that may be in addition to previously discovered connexins at sites of myocyte-nonmyocyte contact in the heart. These findings call for reevaluation of cardiac nonmyocyte roles in electrical connectivity of the heterocellular heart.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::231602b2f617385b2ef5bf78ea3e864fTest
https://doi.org/10.1073/pnas.1611184114Test

المؤلفون: Pengpeng Bi, John R. McAnally, Eric N. Olson, John M. Shelton, Rhonda Bassel-Duby, Efrain Sanchez-Ortiz

المصدر: Proceedings of the National Academy of Sciences. 115:3864-3869

مصطلحات موضوعية: Male, 0301 basic medicine, Satellite Cells, Skeletal Muscle, Population, Muscle Proteins, Biology, Cell Fusion, Mice, 03 medical and health sciences, Myoblast fusion, 0302 clinical medicine, Conditional gene knockout, medicine, Animals, Regeneration, Myocyte, Muscle, Skeletal, education, Mice, Knockout, education.field_of_study, Multidisciplinary, Cell fusion, Regeneration (biology), Membrane Proteins, Skeletal muscle, Biological Sciences, Cell biology, 030104 developmental biology, medicine.anatomical_structure, Female, Stem cell, 030217 neurology & neurosurgery

الوصف: Regeneration of skeletal muscle in response to injury occurs through fusion of a population of stem cells, known as satellite cells, with injured myofibers. Myomixer, a muscle-specific membrane micropeptide, cooperates with the transmembrane protein Myomaker to regulate embryonic myoblast fusion and muscle formation. To investigate the role of Myomixer in muscle regeneration, we used CRISPR/Cas9-mediated genome editing to generate conditional knockout Myomixer alleles in mice. We show that genetic deletion of Myomixer in satellite cells using a tamoxifen-regulated Cre recombinase transgene under control of the Pax7 promoter abolishes satellite cell fusion and prevents muscle regeneration, resulting in severe muscle degeneration after injury. Satellite cells devoid of Myomixer maintain expression of Myomaker, demonstrating that Myomaker alone is insufficient to drive myoblast fusion. These findings, together with prior studies demonstrating the essentiality of Myomaker for muscle regeneration, highlight the obligatory partnership of Myomixer and Myomaker for myofiber formation throughout embryogenesis and adulthood.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f7b6a51c4d1719eb314b7e87326fe7d4Test
https://doi.org/10.1073/pnas.1800052115Test

المؤلفون: Eric N. Olson, Elizabeth H. Chen, Pengpeng Bi, Rhonda Bassel-Duby, Jun Shi, Nick V. Grishin, Jimin Pei, Hui Li

المصدر: Proceedings of the National Academy of Sciences. 114:11950-11955

مصطلحات موضوعية: 0301 basic medicine, Elephants, Muscle Fibers, Skeletal, Muscle Proteins, Biology, Muscle Development, Cell Line, Conserved sequence, Cell Fusion, Myoblasts, 03 medical and health sciences, Myoblast fusion, Animals, CRISPR, Myocyte, Amino Acid Sequence, Zebrafish, Genetics, Multidisciplinary, Myogenesis, Cas9, Membrane Proteins, Biological Sciences, Zebrafish Proteins, biology.organism_classification, Turtles, Cell biology, 030104 developmental biology, Membrane protein, Sharks, CRISPR-Cas Systems

الوصف: Skeletal muscle formation requires fusion of mononucleated myoblasts to form multinucleated myofibers. The muscle-specific membrane proteins myomaker and myomixer cooperate to drive mammalian myoblast fusion. Whereas myomaker is highly conserved across diverse vertebrate species, myomixer is a micropeptide that shows relatively weak cross-species conservation. To explore the functional conservation of myomixer, we investigated the expression and function of the zebrafish myomixer ortholog. Here we show that myomixer expression during zebrafish embryogenesis coincides with myoblast fusion, and genetic deletion of myomixer using CRISPR/Cas9 mutagenesis abolishes myoblast fusion in vivo. We also identify myomixer orthologs in other species of fish and reptiles, which can cooperate with myomaker and substitute for the fusogenic activity of mammalian myomixer. Sequence comparison of these diverse myomixer orthologs reveals key amino acid residues and a minimal fusogenic peptide motif that is necessary for promoting cell-cell fusion with myomaker. Our findings highlight the evolutionary conservation of the myomaker-myomixer partnership and provide insights into the molecular basis of myoblast fusion.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9a4b768b89df315b8a7049f9e0b86bb2Test
https://doi.org/10.1073/pnas.1715229114Test

المؤلفون: Guoliang Li, Xiaojing Wang, Bo Zuo, Hong Mei Luo, Zai Yan Xu, Shanshan Wang, An Dai Zheng, Rui Zeng, Jianjun Jin, Pan Xia, Wei Lv

المصدر: Proceedings of the National Academy of Sciences. 115

مصطلحات موضوعية: 0301 basic medicine, Myoblast proliferation, Multidisciplinary, Myogenesis, Biology, Long non-coding RNA, Cell biology, 03 medical and health sciences, 030104 developmental biology, Myosin, SYNPO2, Myocyte, C2C12, Myogenin

الوصف: Although many long noncoding RNAs (lncRNAs) have been identified in muscle, their physiological function and regulatory mechanisms remain largely unexplored. In this study, we systematically characterized the expression profiles of lncRNAs during C2C12 myoblast differentiation and identified an intronic lncRNA, SYISL (SYNPO2 intron sense-overlapping lncRNA), that is highly expressed in muscle. Functionally, SYISL promotes myoblast proliferation and fusion but inhibits myogenic differentiation. SYISL knockout in mice results in significantly increased muscle fiber density and muscle mass. Mechanistically, SYISL recruits the enhancer of zeste homolog 2 (EZH2) protein, the core component of polycomb repressive complex 2 (PRC2), to the promoters of the cell-cycle inhibitor gene p21 and muscle-specific genes such as myogenin (MyoG), muscle creatine kinase (MCK), and myosin heavy chain 4 (Myh4), leading to H3K27 trimethylation and epigenetic silencing of target genes. Taken together, our results reveal that SYISL is a repressor of muscle development and plays a vital role in PRC2-mediated myogenesis.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::098657cc4911c3e9447e679ef1ae8cf1Test
https://doi.org/10.1073/pnas.1801471115Test

المؤلفون: Yasuyuki Mitani, Yi Li Min, Douglas P. Millay, Malgorzata E. Quinn, Dilani G. Gamage, Rhonda Bassel-Duby, Eric N. Olson

المصدر: Proceedings of the National Academy of Sciences. 113:2116-2121

مصطلحات موضوعية: 0301 basic medicine, Myoblasts, Skeletal, Muscle Proteins, Mutagenesis (molecular biology technique), Mice, Transgenic, Biology, Muscle Development, Cell Line, Cell Fusion, Mice, Structure-Activity Relationship, 03 medical and health sciences, Myoblast fusion, medicine, Animals, Myocyte, Multidisciplinary, Cell Membrane, Membrane Proteins, Skeletal muscle, Biological Sciences, Transmembrane protein, Protein Structure, Tertiary, Cell biology, 030104 developmental biology, medicine.anatomical_structure, Membrane protein, C2C12, Intracellular

الوصف: During skeletal muscle development, myoblasts fuse to form multinucleated myofibers. Myomaker [Transmembrane protein 8c (TMEM8c)] is a muscle-specific protein that is essential for myoblast fusion and sufficient to promote fusion of fibroblasts with muscle cells; however, the structure and biochemical properties of this membrane protein have not been explored. Here, we used CRISPR/Cas9 mutagenesis to disrupt myomaker expression in the C2C12 muscle cell line, which resulted in complete blockade to fusion. To define the functional domains of myomaker required to direct fusion, we established a heterologous cell-cell fusion system, in which fibroblasts expressing mutant versions of myomaker were mixed with WT myoblasts. Our data indicate that the majority of myomaker is embedded in the plasma membrane with seven membrane-spanning regions and a required intracellular C-terminal tail. We show that myomaker function is conserved in other mammalian orthologs; however, related family members (TMEM8a and TMEM8b) do not exhibit fusogenic activity. These findings represent an important step toward deciphering the cellular components and mechanisms that control myoblast fusion and muscle formation.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0dd0bdaa976d69090e68aa4507905242Test
https://doi.org/10.1073/pnas.1600101113Test