scholarly journals Epigenetic Changes Governing Scn5a Expression in Denervated Skeletal Muscle

2021 ◽  
Vol 22 (5) ◽  
pp. 2755
Author(s):  
David Carreras ◽  
Rebecca Martinez-Moreno ◽  
Mel·lina Pinsach-Abuin ◽  
Manel M. Santafe ◽  
Pol Gomà ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Tissue ◽  
Mrna Levels ◽  
Striated Muscles ◽  
Aberrant Expression ◽  
Protein Coding ◽  
Α Subunit ◽  
Super Enhancer ◽  
Cardiac Sodium Channel ◽  
Scn5a Gene

The SCN5A gene encodes the α-subunit of the voltage-gated cardiac sodium channel (NaV1.5), a key player in cardiac action potential depolarization. Genetic variants in protein-coding regions of the human SCN5A have been largely associated with inherited cardiac arrhythmias. Increasing evidence also suggests that aberrant expression of the SCN5A gene could increase susceptibility to arrhythmogenic diseases, but the mechanisms governing SCN5A expression are not yet well understood. To gain insights into the molecular basis of SCN5A gene regulation, we used rat gastrocnemius muscle four days following denervation, a process well known to stimulate Scn5a expression. Our results show that denervation of rat skeletal muscle induces the expression of the adult cardiac Scn5a isoform. RNA-seq experiments reveal that denervation leads to significant changes in the transcriptome, with Scn5a amongst the fifty top upregulated genes. Consistent with this increase in expression, ChIP-qPCR assays show enrichment of H3K27ac and H3K4me3 and binding of the transcription factor Gata4 near the Scn5a promoter region. Also, Gata4 mRNA levels are significantly induced upon denervation. Genome-wide analysis of H3K27ac by ChIP-seq suggest that a super enhancer recently described to regulate Scn5a in cardiac tissue is activated in response to denervation. Altogether, our experiments reveal that similar mechanisms regulate the expression of Scn5a in denervated muscle and cardiac tissue, suggesting a conserved pathway for SCN5A expression among striated muscles.

mRNA levels for α-subunit of prolyl 4-hydroxylase and fibrillar collagens in immobilized rat skeletal muscle

1999 ◽  
Vol 87 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Xiao-Yan Han ◽  
Wei Wang ◽  
Raili Myllylä ◽  
Paula Virtanen ◽  
Jarmo Karpakka ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Tibialis Anterior ◽  
Collagen Synthesis ◽  
Plantar Flexion ◽  
Mrna Level ◽  
Type I ◽  
Mrna Levels ◽  
Rat Skeletal Muscle ◽  
Α Subunit ◽  
Fibrillar Collagens

There is evidence that immobilization causes a decrease in total collagen synthesis in skeletal muscle within a few days. In this study, early immobilization effects on the expression of prolyl 4-hydroxylase (PH) and the main fibrillar collagens at mRNA and protein levels were investigated in rat skeletal muscle. The right hindlimb was immobilized in full plantar flexion for 1, 3, and 7 days. Steady-state mRNAs for α- and β-subunits of PH and type I and III procollagen, PH activity, and collagen content were measured in gastrocnemius and plantaris muscles. Type I and III procollagen mRNAs were also measured in soleus and tibialis anterior muscles. The mRNA level for the PH α-subunit decreased by 49 and 55% ( P < 0.01) in gastrocnemius muscle and by 41 and 39% ( P < 0.05) in plantaris muscle after immobilization for 1 and 3 days, respectively. PH activity was decreased ( P < 0.05–0.01) in both muscles at days 3 and 7. The mRNA levels for type I and III procollagen were decreased by 26–56% ( P < 0.05–0.001) in soleus, tibialis anterior, and plantaris muscles at day 3. The present results thus suggest that pretranslational downregulation plays a key role in fibrillar collagen synthesis in the early phase of immobilization-induced muscle atrophy.

scholarly journals Cardiac sodium channel, its mutations and their spectrum of arrhythmia phenotypes

2016 ◽  
Vol 26 (3) ◽  
pp. 281 ◽  
Author(s):  
Andrés Ricardo Pérez-Riera ◽  
Rodrigo Daminello Raimundo ◽  
Rodrigo Akira Watanabe ◽  
José Luiz Figueiredo ◽  
Luiz Carlos de Abreu
Keyword(s):  
Sodium Channel ◽  
Cardiac Muscle ◽  
Heart Function ◽  
Heart Diseases ◽  
Cardiac Conduction ◽  
Activation Process ◽  
Α Subunit ◽  
Cardiac Sodium Channel ◽  
Wide Range ◽  
Scn5a Gene

The mechanisms of cellular excitability and propagation of electrical signals in the cardiac muscle are very important functionally and pathologically. The heart is constituted by three types of muscle: atrial, ventricular, and specialized excitatory and conducting fi bers. From a physiological and pathophysiological point of view, the conformational states of the sodium channel during heart function constitute a signifi cant aspect for the diagnosis and treatment of heart diseases. Functional states of the sodium channel (closed, open, and inactivated) and their structure help to understand the cardiac regulation processes. There are areas in the cardiac muscle with anatomical and functional differentiation that present automatism, thus subjecting the rest of the fi bers to their own rhythm. The rate of these (pacemaker) areas could be altered by modifi cations in ions, temperature and especially, the autonomic system. Excitability is a property of the myocardium to react when stimulated. Another electrical property is conductivity, which is characterized by a conduction and activation process, where the action potential, by the all-or-nothing law, travels throughout the heart. Heart relaxation also stands out as an active process, dependent on the energetic output and on specificion and enzymatic actions, with the role of sodium channel being outstanding in the functional process. In the gene mutation aspects that encode the rapid sodium channel (SCN5A gene), this channel is responsible for several phenotypes, such as Brugada syndrome, idiopathic ventricular fibrillation, dilated cardiomyopathy, early repolarization syndrome, familial atrial fibrillation, variant 3 of long QT syndrome, multifocal ectopic ventricular contractions originating in Purkinje arborizations, progressive cardiac conduction defect (Lenègre disease), sudden infant death syndrome, sick sinus syndrome, sudden unexplained nocturnal death syndrome, among other sodium channel alterations with clinical overlapping. Finally, it seems appropriate to consider the “sodium channel syndrome” (mutations in the gene of the α subunit of the sodium channel, SCN5A gene) as a single clinical entity that may manifest in a wide range of phenotypes, to thus have a better insight on these cardiac syndromes and potential outcomes for their clinical treatment.

scholarly journals Role of SCN5A coding and non-coding sequences in Brugada syndrome onset: What’s behind the scenes?

2017 ◽  
Author(s):  
Houria Daimi ◽  
Amel Haj Khelil ◽  
Ali Neji ◽  
Khaldoun Ben Hamda ◽  
Sabri Maaoui ◽  
...  
Keyword(s):  
Genetic Testing ◽  
Binding Site ◽  
Candidate Genes ◽  
Brugada Syndrome ◽  
Genetic Variants ◽  
Sequence Variant ◽  
Α Subunit ◽  
Coding Sequence ◽  
Cardiac Sodium Channel ◽  
Scn5a Gene

AbstractBrugada syndrome (BrS) is a rare inherited cardiac arrhythmia associated with a high risk of sudden cardiac death (SCD) due to ventricular fibrillation (VF). BrS is characterized by coved-type ST-segment elevation in the right precordial leads (V1-V3) in the absence of structural heart disease. This pattern is spontaneous, or is unmasked by intravenous administration of Class I antiarrhythmic drugs. The SCN5A-encoded α-subunit of the NaV1.5 cardiac sodium channel has been linked to BrS, and mutations in SCN5A are identified in 15–30% of BrS cases. Genetic testing of BrS patients generally involves sequencing of protein-coding portions and flanking intronic regions of SCN5A, according to recent international guidelines. This excludes the regulatory untranslated regions (5’UTR and 3’UTR) from the routine genetic testing of BrS patients. We here screened the coding sequence, the flanking intronic regions as well as the 5’ and 3’UTR regions of SCN5A gene and further five candidate genes (GPD1L, SCN1B, KCNE3, SCN4B, and MOG1) in a Tunisian family diagnosed with Brugada syndrome.A new Q1000K mutation was identified on the SCN5A gene along with two common polymorphisms (H558R and D1819). Furthermore, multiple genetic variants were identified on the SCN5A 3’UTR, one of which is predicted to create additional microRNA (miRNAs) binding site for miR-1270. Additionally, we identified the hsa-miR-219a rs107822. No relevant coding sequence variant was identified in the remaining studied candidate genes. Although Q1000K is localized in the conserved binding site of MOG1 which predicts a functional consequence, this new mutation along with the additional variants were differentially distributed among the family members without any clear genotype-phenotype concordance. This gives extra evidences about the complexity of the disease and suggests that the occurrence and prognosis of BrS is most likely controlled by a combination of multiple genetic factors and exposures, rather than a single polymorphism/mutation. Most SCN5A polymorphisms were localized in non-coding regions hypothesizing an impact on the miRNA-target complementarities. In this regard, over-expression of miR-1270 led to a significant decrease of luciferase activity suggesting a direct role regulating SCN5A. Therefore, genetic variants that disrupt its binding affinity to SCN5A 3’UTR and/or its expression might cause loss of normal repression control and be associated to BrS.

scholarly journals Reprogramming mRNA Expression in Response to Defect in RNA Polymerase III Assembly in the Yeast Saccharomyces cerevisiae

2021 ◽  
Vol 22 (14) ◽  
pp. 7298
Author(s):  
Izabela Rudzińska ◽  
Małgorzata Cieśla ◽  
Tomasz W. Turowski ◽  
Alicja Armatowska ◽  
Ewa Leśniewska ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Ribosome Biogenesis ◽  
Rna Polymerase Iii ◽  
Mrna Levels ◽  
Rna Seq ◽  
Yeast Saccharomyces Cerevisiae ◽  
Protein Coding ◽  
General Transcription Factor ◽  
Pol I ◽  
Pol Iii

The coordinated transcription of the genome is the fundamental mechanism in molecular biology. Transcription in eukaryotes is carried out by three main RNA polymerases: Pol I, II, and III. One basic problem is how a decrease in tRNA levels, by downregulating Pol III efficiency, influences the expression pattern of protein-coding genes. The purpose of this study was to determine the mRNA levels in the yeast mutant rpc128-1007 and its overdose suppressors, RBS1 and PRT1. The rpc128-1007 mutant prevents assembly of the Pol III complex and functionally mimics similar mutations in human Pol III, which cause hypomyelinating leukodystrophies. We applied RNAseq followed by the hierarchical clustering of our complete RNA-seq transcriptome and functional analysis of genes from the clusters. mRNA upregulation in rpc128-1007 cells was generally stronger than downregulation. The observed induction of mRNA expression was mostly indirect and resulted from the derepression of general transcription factor Gcn4, differently modulated by suppressor genes. rpc128-1007 mutation, regardless of the presence of suppressors, also resulted in a weak increase in the expression of ribosome biogenesis genes. mRNA genes that were downregulated by the reduction of Pol III assembly comprise the proteasome complex. In summary, our results provide the regulatory links affected by Pol III assembly that contribute differently to cellular fitness.

scholarly journals Smooth muscle myosin light chain kinase expression in cardiac and skeletal muscle

2000 ◽  
Vol 279 (5) ◽  
pp. C1656-C1664 ◽  
Author(s):  
B. Paul Herring ◽  
Shelley Dixon ◽  
Patricia J. Gallagher
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Cardiac Myocyte ◽  
Cardiac Tissue ◽  
Specific Protein ◽  
Myoblast Differentiation ◽  
Adult Skeletal Muscle

The purpose of this study was to characterize myosin light chain kinase (MLCK) expression in cardiac and skeletal muscle. The only classic MLCK detected in cardiac tissue, purified cardiac myocytes, and in a cardiac myocyte cell line (AT1) was identical to the 130-kDa smooth muscle MLCK (smMLCK). A complex pattern of MLCK expression was observed during differentiation of skeletal muscle in which the 220-kDa-long or “nonmuscle” form of MLCK is expressed in undifferentiated myoblasts. Subsequently, during myoblast differentiation, expression of the 220-kDa MLCK declines and expression of this form is replaced by the 130-kDa smMLCK and a skeletal muscle-specific isoform, skMLCK in adult skeletal muscle. These results demonstrate that the skMLCK is the only tissue-specific MLCK, being expressed in adult skeletal muscle but not in cardiac, smooth, or nonmuscle tissues. In contrast, the 130-kDa smMLCK is ubiquitous in all adult tissues, including skeletal and cardiac muscle, demonstrating that, although the 130-kDa smMLCK is expressed at highest levels in smooth muscle tissues, it is not a smooth muscle-specific protein.

Effect of experimental hypercholesterolaemia on K+ channel α-subunit mRNA levels in rabbit hearts

2007 ◽  
Vol 562 (1-2) ◽  
pp. 130-131 ◽  
Author(s):  
Angelika Varga ◽  
Péter Bagossi ◽  
József Tözsér ◽  
Barna Peitl ◽  
Zoltán Szilvássy
Keyword(s):  
K Channel ◽  
Mrna Levels ◽  
Α Subunit ◽  
Subunit Mrna

Transcriptional regulation of gene expression in human skeletal muscle during recovery from exercise

2000 ◽  
Vol 279 (4) ◽  
pp. E806-E814 ◽  
Author(s):  
Henriette Pilegaard ◽  
George A. Ordway ◽  
Bengt Saltin ◽  
P. Darrell Neufer
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Human Skeletal Muscle ◽  
Molecular Mechanisms ◽  
Uncoupling Protein ◽  
Pyruvate Dehydrogenase Kinase ◽  
Heme Oxygenase 1 ◽  
Metabolic Efficiency ◽  
Vastus Lateralis Muscle ◽  
Mrna Levels

Exercise training elicits a number of adaptive changes in skeletal muscle that result in an improved metabolic efficiency. The molecular mechanisms mediating the cellular adaptations to exercise training in human skeletal muscle are unknown. To test the hypothesis that recovery from exercise is associated with transcriptional activation of specific genes, six untrained male subjects completed 60–90 min of exhaustive one-legged knee extensor exercise for five consecutive days. On day 5, nuclei were isolated from biopsies of the vastus lateralis muscle of the untrained and the trained leg before exercise and from the trained leg immediately after exercise and after 15 min, 1 h, 2 h, and 4 h of recovery. Transcriptional activity of the uncoupling protein 3 (UCP3), pyruvate dehydrogenase kinase 4 (PDK4), and heme oxygenase-1 (HO-1) genes (relative to β-actin) increased by three- to sevenfold in response to exercise, peaking after 1–2 h of recovery. Increases in mRNA levels followed changes in transcription, peaking between 2 and 4 h after exercise. Lipoprotein lipase and carnitine pamitoyltransferase I gene transcription and mRNA levels showed similar but less dramatic induction patterns, with increases ranging from two- to threefold. In a separate study, a single 4-h bout of cycling exercise ( n = 4) elicited from 5 to >20-fold increases in UCP3, PDK4, and HO-1 transcription, suggesting that activation of these genes may be related to the duration or intensity of exercise. These data demonstrate that exercise induces transient increases in transcription of metabolic genes in human skeletal muscle. Moreover, the findings suggest that the cumulative effects of transient increases in transcription during recovery from consecutive bouts of exercise may represent the underlying kinetic basis for the cellular adaptations associated with exercise training.

Transmembrane prolyl 4-hydroxylase is a fourth prolyl 4-hydroxylase regulating EPO production and erythropoiesis

Blood ◽  
2012 ◽  
Vol 120 (16) ◽  
pp. 3336-3344 ◽  
Author(s):  
Anu Laitala ◽  
Ellinoora Aro ◽  
Gail Walkinshaw ◽  
Joni M. Mäki ◽  
Maarit Rossi ◽  
...  
Keyword(s):  
Cultured Cells ◽  
Mrna Level ◽  
Hypoxia Inducible Factor ◽  
Mrna Levels ◽  
Wild Type ◽  
Α Subunit ◽  
Hepcidin Expression ◽  
In The Wild ◽  
Hepcidin Mrna

AbstractAn endoplasmic reticulum transmembrane prolyl 4-hydroxylase (P4H-TM) is able to hydroxylate the α subunit of the hypoxia-inducible factor (HIF) in vitro and in cultured cells, but nothing is known about its roles in mammalian erythropoiesis. We studied such roles here by administering a HIF-P4H inhibitor, FG-4497, to P4h-tm−/− mice. This caused larger increases in serum Epo concentration and kidney but not liver Hif-1α and Hif-2α protein and Epo mRNA levels than in wild-type mice, while the liver Hepcidin mRNA level was lower in the P4h-tm−/− mice than in the wild-type. Similar, but not identical, differences were also seen between FG-4497–treated Hif-p4h-2 hypomorphic (Hif-p4h-2gt/gt) and Hif-p4h-3−/− mice versus wild-type mice. FG-4497 administration increased hemoglobin and hematocrit values similarly in the P4h-tm−/− and wild-type mice, but caused higher increases in both values in the Hif-p4h-2gt/gt mice and in hematocrit value in the Hif-p4h-3−/− mice than in the wild-type. Hif-p4h-2gt/gt/P4h-tm−/− double gene-modified mice nevertheless had increased hemoglobin and hematocrit values without any FG-4497 administration, although no such abnormalities were seen in the Hif-p4h-2gt/gt or P4h-tm−/− mice. Our data thus indicate that P4H-TM plays a role in the regulation of EPO production, hepcidin expression, and erythropoiesis.

scholarly journals Immunocytochemical localization of mitochondrial carbonic anhydrase in rat tissues.

1991 ◽  
Vol 39 (4) ◽  
pp. 451-459 ◽  
Author(s):  
H K Väänänen ◽  
N D Carter ◽  
S J Dodgson
Keyword(s):  
Skeletal Muscle ◽  
Carbonic Anhydrase ◽  
Cardiac Tissue ◽  
Polyclonal Antiserum ◽  
Heterogeneous Population ◽  
Rat Tissues ◽  
Staining Reaction ◽  
Gastric Parietal Cells ◽  
First Time ◽  
Carbonic Anhydrase Gene

We used a monospecific polyclonal antiserum against mitochondrial carbonic anhydrase (CA V) from rat liver to study tissue localization of this new member of the carbonic anhydrase gene family. Strong granular immunostaining reaction of CA V was observed in hepatocytes, myocardium, and in certain populations of skeletal muscle fibers. This is the first time that mitochondrial carbonic anhydrase is described in cardiac tissue of rat or any other species. Different epithelial cells revealed very heterogeneous staining reaction, suggesting that mitochondria are a heterogeneous population with respect to their CA V content. Many cells in different glandular epithelia did not show any CA V, whereas some cells, such as gastric parietal cells, were intensely stained with CA V antibodies. No systematic co-expression of CA V with CA I, CA II, or CA III was observed, although the distribution of CA V in skeletal muscle was somewhat similar to that of CA III. Connective tissue cells such as fibroblasts, chondroblasts, and osteoblasts were negative.

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