Publications by authors named "Rodney G"

Eccentric contraction- (ECC) induced force loss is a hallmark of murine dystrophin-deficient (mdx) skeletal muscle that is used to assess efficacy of potential therapies for Duchenne muscular dystrophy. While virtually all key proteins involved in muscle contraction have been implicated in ECC force loss, a unifying mechanism that orchestrates force loss across such diverse molecular targets has not been identified. We showed that correcting defective hydrogen sulfide (H2S) signaling in mdx muscle prevented ECC force loss.

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Dilated cardiomyopathy (DCM) is a highly prevalent and genetically heterogeneous condition that results in decreased contractility and impaired cardiac function. The FK506-binding protein FKBP12 has been implicated in regulating the ryanodine receptor in skeletal muscle, but its role in cardiac muscle remains unclear. To define the effect of FKBP12 in cardiac function, we generated conditional mouse models of FKBP12 deficiency.

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Skeletal muscle cells (myofibers) are elongated non-mitotic, multinucleated syncytia that have adapted a microtubule lattice. Microtubule-associated proteins (MAPs) play roles in regulating microtubule architecture. The most abundant MAP in skeletal muscle is MAP4.

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Aim: Duchenne muscular dystrophy is a progressive muscle-wasting disease caused by mutations in the dystrophin gene. Despite progress in dystrophin-targeted gene therapies, it is still a fatal disease requiring novel therapeutics that can be used synergistically or alternatively to emerging gene therapy. Defective autophagy and disorganized microtubule networks contribute to dystrophic pathogenesis, yet the mechanisms by which microtubule alterations regulate autophagy remain elusive.

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Here we show that striated muscle preferentially expressed protein kinase α (Spegα) maintains cardiac function in hearts with Spegβ deficiency. Speg is required for stability of excitation-contraction coupling (ECC) complexes and interacts with esterase D (Esd), Cardiomyopathy-Associated Protein 5 (Cmya5), and Fibronectin Type III and SPRY Domain Containing 2 (Fsd2) in cardiac and skeletal muscle. Mice with a sequence encoding a V5/HA tag inserted into the first exon of the Speg gene (HA-Speg mice) display a >90% decrease in Spegβ but Spegα is expressed at ~50% of normal levels.

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Article Synopsis
  • Postnatal skeletal muscle development involves significant changes in gene splicing, essential for adapting muscle function from fetal to adult stages.
  • The protein LIMCH1 is crucial in this process, with two spliced isoforms: uLIMCH1 (fetal) and mLIMCH1 (muscle-specific), which are produced differently during and after birth.
  • Knockout studies using CRISPR/Cas9 on mLIMCH1 in mice showed that the lack of this isoform leads to muscle weakness and impaired calcium handling, highlighting its importance in muscle function and the broader implications for conditions like muscular dystrophy.
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Perturbation to the redox state accompanies many diseases and its effects are viewed through oxidation of biomolecules, including proteins, lipids, and nucleic acids. The thiol groups of protein cysteine residues undergo an array of redox post-translational modifications (PTMs) that are important for regulation of protein and pathway function. To better understand what proteins are redox regulated following a perturbation, it is important to be able to comprehensively profile protein thiol oxidation at the proteome level.

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Cancer cachexia is a lethal metabolic syndrome featuring muscle wasting with preferential loss of fast-twitching muscle mass through an undefined mechanism. Here, we show that cancer induces muscle wasting by selectively degrading myosin heavy chain (MHC) subtypes IIb and IIx through E3 ligase UBR2-mediated ubiquitylation. Induction of MHC loss and atrophy in C2C12 myotubes and mouse tibialis anterior (TA) by murine cancer cells required UBR2 up-regulation by cancer.

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  • Fibro-adipogenic progenitors (FAPs) in muscle tissues help muscle regeneration but become senescent in aging, affecting their interaction with muscle progenitor/stem cells (MPCs), especially in Hutchinson-Gilford progeria syndrome (HGPS).
  • In a study comparing normal WT mice to Zmpste24 (Z24) mice, Z24 mice showed significantly more FAPs and fewer MPCs, with a high percentage of senescent FAPs, which negatively impacted the proliferation and muscle formation capabilities of MPCs.
  • Administering the senolytic drug fisetin successfully reduced senescent FAPs, improved the function of MPCs, and showed promising results in
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  • Dilated cardiomyopathy is a major cause of death in Duchenne muscular dystrophy (DMD) due to the absence of the dystrophin protein, leading to disorganization of heart muscle cells and gap junctions.
  • Research shows that the phosphorylation of connexin-43 (Cx43) is crucial for its proper function and localization, and that microtubule (MT) organization affects this process.
  • Treatment with colchicine improved the structure of MTs and reduced harmful heart remodeling in DMD mice, highlighting the need for understanding pS-Cx43 and MT interactions to create new therapies for DMD-related heart issues.
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Obesity is often associated with metabolic dysregulation and oxidative stress with the latter serving as a possible unifying link between obesity and cardiovascular complications. Glutaredoxins (Grxs) comprise one of the major antioxidant systems in the heart. Although Grx3 has been shown to act as an endogenous negative regulator of cardiac hypertrophy and heart failure, its metabolic impact on cardiac function in diet-induced obese (DIO) mice remains largely unknown.

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Skeletal muscle contraction depends on activation of clustered acetylcholine receptors (AchRs) and muscle-specific Na channels (Nav1.4). Some Nav1.

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This guideline updates and replaces the 5th edition of the Standards of Monitoring published in 2015. The aim of this document is to provide guidance on the minimum standards for monitoring of any patient undergoing anaesthesia or sedation under the care of an anaesthetist. The recommendations are primarily aimed at anaesthetists practising in the UK and Ireland, but it is recognised that these guidelines may also be of use in other areas of the world.

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Article Synopsis
  • In 2008, guidelines were established for researching autophagy, which has since gained significant interest and new technologies, necessitating regular updates to monitoring methods across various organisms.
  • The new guidelines emphasize selecting appropriate techniques to evaluate autophagy while noting that no single method suits all situations; thus, a combination of methods is encouraged.
  • The document highlights that key proteins involved in autophagy also impact other cellular processes, suggesting genetic studies should focus on multiple autophagy-related genes to fully understand these pathways.
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The ability for skeletal muscle to perform optimally can be affected by the regulation of Ca within the triadic junctional space at rest. Reactive oxygen species impact muscle performance due to changes in oxidative stress, damage and redox regulation of signaling cascades. The interplay between ROS and Ca signaling at the triad of skeletal muscle is therefore important to understand as it can impact the performance of healthy and diseased muscle.

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Article Synopsis
  • Growing evidence indicates that glutaredoxins, particularly Grx3, are important for protecting heart cells from oxidative stress and regulating redox states.
  • In a study using mice where Grx3 was specifically deleted in heart muscle cells, it was found that while these mice appeared normal at a young age, they developed significant heart issues, including hypertrophy and decreased heart function by 12 months.
  • The research highlights that Grx3 plays a critical role in maintaining cellular health in the heart by managing reactive oxygen species and calcium handling, suggesting a link between Grx3 and heart disease progression.
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Specialized adult somatic cells, such as cardiomyocytes (CMs), are highly differentiated with poor renewal capacity, an integral reason underlying organ failure in disease and aging. Among the least renewable cells in the human body, CMs renew approximately 1% annually. Consistent with poor CM turnover, heart failure is the leading cause of death.

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  • Impaired growth during fetal life can lead to heart development changes, increasing cardiovascular dysfunction risk later in life.
  • Research indicates that the timing of nutritional deficiencies could affect heart vulnerability even after birth, particularly in female mice.
  • Female mice undernourished early showed smaller hearts and limited heart functionality, suggesting ongoing risks for heart problems in contexts like intense exercise.
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