Muscle Cell News Volume 1.23 | Aug 29 2016

TOP STORY

Cardiomyopathy in BRAF-Mutant hiPSC-Derived Cardiomyocytes

By cell sorting for SIRPα and CD90, researchers generated a method to examine human induced pluripotent stem cell-derived cell type-specific phenotypes and cellular interactions underpinning hypertrophic cardiomyopathy. BRAF-mutant SIRPα⁺/CD90⁻ cardiomyocytes displayed cellular hypertrophy, pro-hypertrophic gene expression, and intrinsic calcium-handling defects. [Stem Cell Reports] Full Article | Graphical Abstract

(Ranked by impact factor of the journal)

CARDIAC MUSCLE CELLS

Natural Myocardial ECM Patch Drives Cardiac Progenitor Based Restoration Even after Scarring

Researchers showed that both acute and long-term chronic myocardial infarction models, porcine cardiac extracellular matrix (ECM) promotes significant cardiac function improvement, which is correlated to progenitor and myocyte recruitment. Recruited progenitors, isolated using laser capture microdissection, expressed both early and late cardiomyocyte (CM) differentiation markers, suggesting differentiation towards the CM lineage. [Acta Biomater] Abstract

Mitochondrial Pyruvate Dehydrogenase Phosphatase 1 Regulates the Early Differentiation of Cardiomyocytes from Mouse Embryonic Stem Cells

The authors aimed to determine the potential mitochondrial factor that controls the differentiation of embryonic stem cells (ESCs) into cardiac myocytes. They induced cardiomyocyte differentiation from mouse ESCs (mESCs) and performed microarray assays to assess messenger RNA expression changes at differentiation day 8 compared with undifferentiated mESCs. [Exp Mol Med] Full Article

Desmin and αB-Crystallin Interplay in Maintenance of Mitochondrial Homeostasis and Cardiomyocyte Survival

Researchers investigated the consequences of αΒ-crystallin overexpression in the desmin deficient mouse model, which possesses a combination of the pathologies found in most cardiomyopathies, with mitochondrial defects as a hallmark. They demonstrated that cardiac specific αΒ-crystallin overexpression ameliorates all these defects and significantly improves cardiac function to almost wild type levels. [J Cell Sci] Abstract

Illuminating Myocyte-Fibroblast Homotypic and Heterotypic Gap Junction Dynamics Using Dynamic Clamp

In the heart, three major connexin (Cx) isoforms, Cx40, Cx43, and Cx45, form gap junction (GJ) channels in cell-type-specific combinations. Because each Cx is characterized by a unique time- and transjunctional voltage-dependent profile, the authors investigated whether the electrophysiological contributions of fibroblasts would vary with the specific composition of the myocyte-fibroblast GJ channel. [Biophys J] Abstract

Caveolin-1 Plays an Important Role in the Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells into Cardiomyocytes

Researchers investigated the functional role of caveolin-1 in the cardiomyocyte differentiation of marrow-derived mesenchymal stem cells and explored the potential underlying molecular mechanisms. [Cardiology] Abstract

SKELETAL MUSCLE CELLS

Skeletal Muscle Specific G Protein-Coupled Receptor Kinase 2 Ablation Alters Isolated Skeletal Muscle Mechanics and Enhances Clenbuterol-Stimulated Hypertrophy

Researchers generated a novel skeletal muscle specific GRK2 knockout mouse to gain a better understanding of the role of GRK2 in skeletal muscle physiology. In isolated muscle mechanics testing, GRK2 ablation caused a significant decrease in the specific force of contraction of the fast-twitch extensor digitorum longus muscle, yet had no effect on the slow-twitch soleus muscle. [J Biol Chem] Abstract | Full Article

Contractile Properties of Motor Units and Expression of Myosin Heavy Chain Isoforms in Rat Fast-Type Muscle after Volitional Weight-Lifting Training

The authors examined MU contractile properties, the mRNA expression of myosin heavy chain (MyHC), parvalbumin, and sarcoendoplasmic reticulum Ca2⁺ pump isoforms, as well as the MyHC protein content after five weeks of volitional progressive weight lifting training in the medial gastrocnemius muscle in rats. [J Appl Physiol] Abstract

miR-378 Attenuates Muscle Regeneration by Delaying Satellite Cell Activation and Differentiation in Mice

The authors used miR-378 transgenic (Tg) mice to assess the in vivo functional effects of miR-378 on skeletal muscle growth and regeneration. Cross-sectional analysis of skeletal muscle tissues showed that the number and size of myofibers were significantly lower in miR-378 Tg mice than in wild-type mice. [Acta Biochim Biophys Sin] Abstract

SMOOTH MUSCLE CELLS

Hypoxia-Inducible Factor-1a in Smooth Muscle Cells Protects Against Aortic Aneurysms

The authors found that deficiency of smooth muscle cell-derived hypoxia-inducible factor-1a augments aortic aneurysms, accompanied by disruption of elastin fiber formation, but not changes of elastin fiber degradation. [Arterioscler Thromb Vasc Biol] Abstract

TLR4-Activated MAPK-IL-6 Axis Regulates Vascular Smooth Muscle Cell Function

Researchers aimed to elucidate the mechanism by which Toll-like receptor 4 (TLR4) regulates vascular smooth muscle cells (VSMC) migration. Inhibitor experiments revealed that TLR4-induced IL-6 secretion and VSMC migration were mediated via the concerted actions of MyD88 and TRIF on the activation of p38 MAPK and ERK1/2 signaling. [Int J Mol Sci] Full Article

Connective Tissue Regeneration in Skeletal Muscle after Eccentric Contraction-Induced Injury

The role of individual muscle matrix components and their spatial interaction during adaptation to eccentric contractions is an unexplored field in human skeletal muscle and may provide insight into the optimal timing of rest vs. return to activity after muscle injury. [J Appl Physiol] Abstract

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Results from Pre-Clinical Study Using CardioCell’s Stem Cells for Acute Myocardial Infarction (AMI)

CardioCell LLC announced data from its pre-clinical study “Mesenchymal stem cells grown under chronic hypoxia traffic to regions of myocardial infarction, suppress splenic natural killer cells, and attenuate adverse remodeling in mice with large acute MI.” [Press release from CardioCell LLC discussing research presented at the European Society of Cardiology (ESC) Congress, Rome] Press Release

Audentes Therapeutics Announces First Patient Enrolled in the INCEPTUS Clinical Assessment Study of XLMTM

Audentes Therapeutics, Inc. reported that the first patient has been enrolled in INCEPTUS, a prospective study designed to characterize the disease presentation in children living with X-Linked Myotubular Myopathy (XLMTM). [Audentes Therapeutics, Inc.] Press Release

Mallinckrodt Receives FDA Fast-Track Designation for Synacthen^® Depot IND Application

Mallinckrodt plc announced the U.S. Food and Drug Administration (FDA) has granted the company’s request for a Fast Track designation for its Investigational New Drug (IND) application for Synacthen^® Depot in the treatment of Duchenne muscular dystrophy. Synacthen Depot is a depot formulation of Synacthen, a synthetic 24 amino acid melanocortin receptor agonist. [Mallinckrodt plc] Press Release

Special: Obama’s Science Legacy

The United States will elect a new president in November 2016. Nature is tracking the battle between Republican Donald Trump and Democrat Hillary Clinton — and analyzing how the election outcome could affect science. [Nature] Editorial

New Leader of NIH’s Research Watchdog Faces Staff Revolt

The Office of Research Integrity (ORI) in Rockville, Maryland, which guards against misconduct in biomedical research, usually attracts attention with its findings, not its internal workings. But two years ago, its director, David Wright, quit in a public huff, complaining that ORI was hobbled by a dysfunctional federal bureaucracy. Now, his successor is encountering her own rough waters, Science has learned. [ScienceInsider] Editorial

Putin Appoints Church Historian as Science Minister

Russian President Vladimir Putin has appointed a church historian as the country’s new science and education minister. The president announced that Olga Vasilyeva would succeed the current science minister, Dmitry Livanov, who will become presidential envoy on trade and economic relations with Ukraine, according to the Russian news agency Interfax. [Nature News] Editorial

NEW 7^th International Conference on Stem Cells and Cancer (ICSCC-2016): Proliferation, Differentiation and Apoptosis
October 21-23, 2016
Goa, India

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NEW Biological Data Analyst – Prediction and Understanding of Cardiac and Hepatic Toxicities (European Molecular Biology Laboratory)

NEW Postdoctoral Fellowships – Cardiac Signal Processing and Instrumentation (Massachusetts General Hospital)

Faculty Positions – Cell and Molecular Physiology (Loyola University Chicago)

Faculty Positions – Genetics and Genomics (Boston University)

Research Technician – Muscle Growth and Wasting (Howard Hughes Medical Institute)

Research Associate – Lipid Metabolism (Wright State University, Boonshoft School of Medicine)

Postdoctoral Position – Cardiovascular Stem Cell Biology (Yale University)

Postdoctoral Research Fellowship – Functional Genomics and Bioinformatics (L’Institut du Thorax)

Postdoctoral Position – Biomedical Engineering (University of South Dakota)

Postdoctoral Position – Duchenne Muscular Dystrophy (Leiden University Medical Center)

Postdoctoral Position – Epigenetics and Cell Differentiation (Centre National de la Recherche Scientifique)

Postdoctoral Fellow – Muscle Energetics (National Institutes of Health)

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