Substrate utilisation of cultured skeletal muscle cells in patients with CFS

Abstract Chronic fatigue syndrome (CFS) patients often suffer from severe muscle pain and an inability to exercise due to muscle fatigue. It has previously been shown that CFS skeletal muscle cells have lower levels of ATP and have AMP-activated protein kinase dysfunction. This study outlines experiments looking at the utilisation of different substrates by skeletal muscle cells from CFS patients (n = 9) and healthy controls (n = 11) using extracellular flux analysis. Results show that CFS skeletal muscle cells are unable to utilise glucose to the same extent as healthy control cells. CFS skeletal muscle cells were shown to oxidise galactose and fatty acids normally, indicating that the bioenergetic dysfunction lies upstream of the TCA cycle. The dysfunction in glucose oxidation is similar to what has previously been shown in blood cells from CFS patients. The consistency of cellular bioenergetic dysfunction in different cell types supports the hypothesis that CFS is a systemic disease. The retention of bioenergetic defects in cultured cells indicates that there is a genetic or epigenetic component to the disease. This is the first study to use cells derived from skeletal muscle biopsies in CFS patients and healthy controls to look at cellular bioenergetic function in whole cells.

Download Full-text

Annexins and Membrane Repair Dysfunctions in Muscular Dystrophies

International Journal of Molecular Sciences ◽

10.3390/ijms22105276 ◽

2021 ◽

Vol 22 (10) ◽

pp. 5276

Author(s):

Coralie Croissant ◽

Romain Carmeille ◽

Charlotte Brévart ◽

Anthony Bouter

Keyword(s):

Skeletal Muscle ◽

Muscular Dystrophy ◽

Genetic Disorders ◽

Muscle Cells ◽

Cell Types ◽

Clinical Severity ◽

Skeletal Muscle Cells ◽

Muscular Dystrophies ◽

Membrane Repair ◽

Human Skeletal Muscle Cells

Muscular dystrophies constitute a group of genetic disorders that cause weakness and progressive loss of skeletal muscle mass. Among them, Miyoshi muscular dystrophy 1 (MMD1), limb girdle muscular dystrophy type R2 (LGMDR2/2B), and LGMDR12 (2L) are characterized by mutation in gene encoding key membrane-repair protein, which leads to severe dysfunctions in sarcolemma repair. Cell membrane disruption is a physiological event induced by mechanical stress, such as muscle contraction and stretching. Like many eukaryotic cells, muscle fibers possess a protein machinery ensuring fast resealing of damaged plasma membrane. Members of the annexins A (ANXA) family belong to this protein machinery. ANXA are small soluble proteins, twelve in number in humans, which share the property of binding to membranes exposing negatively-charged phospholipids in the presence of calcium (Ca2+). Many ANXA have been reported to participate in membrane repair of varied cell types and species, including human skeletal muscle cells in which they may play a collective role in protection and repair of the sarcolemma. Here, we discuss the participation of ANXA in membrane repair of healthy skeletal muscle cells and how dysregulation of ANXA expression may impact the clinical severity of muscular dystrophies.

Download Full-text

Subcellular Specialization of Mitochondrial Form and Function in Skeletal Muscle Cells

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.757305 ◽

2021 ◽

Vol 9 ◽

Author(s):

T. Bradley Willingham ◽

Peter T. Ajayi ◽

Brian Glancy

Keyword(s):

Skeletal Muscle ◽

Energy Homeostasis ◽

Single Cells ◽

Muscle Cells ◽

Cell Types ◽

Current Data ◽

Skeletal Muscle Cells ◽

Form And Function ◽

Mitochondrial Heterogeneity ◽

And Function

Across different cell types and within single cells, mitochondria are heterogeneous in form and function. In skeletal muscle cells, morphologically and functionally distinct subpopulations of mitochondria have been identified, but the mechanisms by which the subcellular specialization of mitochondria contributes to energy homeostasis in working muscles remains unclear. Here, we discuss the current data regarding mitochondrial heterogeneity in skeletal muscle cells and highlight potential new lines of inquiry that have emerged due to advancements in cellular imaging technologies.

Download Full-text

Immunohistochemical localization of annexin V (CaBP33) in rat organs.

Journal of Histochemistry & Cytochemistry ◽

10.1177/39.9.1833446 ◽

1991 ◽

Vol 39 (9) ◽

pp. 1189-1198 ◽

Cited By ~ 34

Author(s):

I Giambanco ◽

G Pula ◽

P Ceccarelli ◽

R Bianchi ◽

R Donato

Keyword(s):

Skeletal Muscle ◽

Endothelial Cells ◽

Annexin V ◽

Muscle Cells ◽

Cell Types ◽

Skeletal Muscle Cells ◽

Secretory Cells ◽

White Pulp ◽

Rat Tissues ◽

Peritubular Capillaries

We investigated the cellular distribution of annexin V (CaBP33) in rat tissues by immunohistochemistry. Several cell types were shown to express the protein. Glial cells in the cerebellum and in the optic nerve, the corneal epithelium, the posterior epithelium in the iris, chondrocytes, skeletal muscle cells and cardiomyocytes, the capillary endothelial cells in many organs, the muscularis mucosae and the muscular layer in the intestinal tract, hepatocytes, Müller cells in the retina, the lens fibers, Sertoli and Leydig cells in the testis, and smooth muscle cells in the epididymis and bronchi displayed intense immunostaining. In the adrenal gland, only the cortex showed immunoreaction product. In the kidney, no apparent staining of renal cells was observed, whereas endothelial cells of peritubular capillaries were stained. In the heart, annexin V was found associated exclusively with the sarcolemma and intercalated discs, as opposed to the diffuse distribution of the protein in skeletal muscle cells. In the spleen, only reticular elements in the white pulp and endothelial cells in the red pulp appeared to be immunostained. The present data complement the biochemical work thus far done on annexin V and suggest that the protein is neither restricted to secretory cells nor exclusively related to exocytotic events in secretory cells.

Download Full-text

MP473PROTEIN DEGRADATION RATES ARE COMPARABLE IN CULTURED SKELETAL MUSCLE CELLS FROM HUMAN PATIENTS WITH CKD AND HEALTHY CONTROLS

Nephrology Dialysis Transplantation ◽

10.1093/ndt/gfx173.mp473 ◽

2017 ◽

Vol 32 (suppl_3) ◽

pp. iii602-iii602

Author(s):

Douglas Gould ◽

Alice Smith ◽

Emma Watson

Keyword(s):

Skeletal Muscle ◽

Muscle Cells ◽

Skeletal Muscle Cells ◽

Healthy Controls ◽

Degradation Rates

Download Full-text

Abnormalities of AMPK Activation and Glucose Uptake in Cultured Skeletal Muscle Cells from Individuals with Chronic Fatigue Syndrome

PLoS ONE ◽

10.1371/journal.pone.0122982 ◽

2015 ◽

Vol 10 (4) ◽

pp. e0122982 ◽

Cited By ~ 27

Author(s):

Audrey E. Brown ◽

David E. Jones ◽

Mark Walker ◽

Julia L. Newton

Keyword(s):

Skeletal Muscle ◽

Chronic Fatigue Syndrome ◽

Glucose Uptake ◽

Muscle Cells ◽

Chronic Fatigue ◽

Skeletal Muscle Cells ◽

Ampk Activation ◽

Fatigue Syndrome

Download Full-text

Analysis of the upstream regions governing expression of the chicken cardiac troponin T gene in embryonic cardiac and skeletal muscle cells.

The Journal of Cell Biology ◽

10.1083/jcb.107.2.573 ◽

1988 ◽

Vol 107 (2) ◽

pp. 573-585 ◽

Cited By ~ 53

Author(s):

J H Mar ◽

P B Antin ◽

T A Cooper ◽

C P Ordahl

Keyword(s):

Skeletal Muscle ◽

Cardiac Troponin ◽

Troponin T ◽

Muscle Cells ◽

Cell Types ◽

Chloramphenicol Acetyltransferase ◽

Skeletal Muscle Cells ◽

Upstream Region ◽

Cardiac Troponin T ◽

Cis Acting

The chicken gene encoding cardiac troponin T (cTNT) is expressed in both cardiac and skeletal muscle during early embryonic development, but is specifically repressed in skeletal muscle during fetal development. To determine if the cis-acting sequences governing transcription of a single gene in these two related cell types are the same, we have transfected promoter/upstream segments of the cTNT gene coupled to the bacterial chloramphenicol acetyltransferase gene into primary cultures of early embryonic cardiac and skeletal muscle cells. Using this assay system, chloramphenicol acetyltransferase activity directed by the cTNT promoter/upstream region was between two and three orders of magnitude higher in cardiac or skeletal muscle cells than in fibroblast cells, indicating that cis elements responsible for cell-specific expression reside in this region of the cTNT gene. Deletion experiments showed that a 67-nucleotide DNA segment residing between 268 and 201 nucleotides upstream of the cTNT transcription initiation site is required for cTNT promoter activity in embryonic cardiac cells. This region is not required in embryonic skeletal muscle cells because a cTNT promoter construction containing only 129 upstream nucleotides is transcriptionally active in these cells. These results demonstrate that different cis-acting sequences are required for cTNT expression in early embryonic cardiac and skeletal muscle cells. Nonessential regions residing farther upstream, on the other hand, affected the level of expression of these minimum regions in a similar manner in both cell types. The data from these experiments indicate, therefore, that transcription of the cTNT promoter in early embryonic cardiac and skeletal muscle cells is governed both by common and divergent regulatory elements in cis and in trans.

Download Full-text

Aldosterone- and testosterone-mediated intracellular calcium response in skeletal muscle cell cultures

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.2000.279.1.e132 ◽

2000 ◽

Vol 279 (1) ◽

pp. E132-E139 ◽

Cited By ~ 54

Author(s):

Manuel Estrada ◽

José Luis Liberona ◽

Manuel Miranda ◽

Enrique Jaimovich

Keyword(s):

Skeletal Muscle ◽

Intracellular Calcium ◽

Second Messengers ◽

Calcium Transient ◽

Muscle Cells ◽

Cell Types ◽

Skeletal Muscle Cells ◽

Calcium Signal ◽

Cell Nuclei ◽

Acetoxymethyl Ester

Fast nongenomic steroid actions in several cell types seem to be mediated by second messengers such as intracellular calcium ([Ca2+]i) and inositol 1,4,5-trisphosphate (IP3). We have shown the presence of both slow calcium transients and IP3 receptors associated with cell nuclei in cultured skeletal muscle cells. The effect of steroids on [Ca2+]i was monitored in Fluo 3-acetoxymethyl ester-loaded myotubes by either confocal microscopy or fluorescence microscopy, with the use of out-of-focus fluorescence elimination. The mass of IP3 was determined by radioreceptor displacement assay. [Ca2+]ichanges after either aldosterone (10–100 nM) or testosterone (50–100 nM) were observed; a relatively fast (<2 min) calcium transient, frequently accompanied by oscillations, was evident with both hormones. A slow rise in [Ca2+]i that reached its maximum after a 30-min exposure to aldosterone was also observed. Calcium responses seem to be fairly specific for aldosterone and testosterone, because several other steroid hormones do not induce detectable changes in fluorescence, even at 100-fold higher concentrations. The mass of IP3 increased transiently to reach two- to threefold the basal level 45 s after addition of either aldosterone or testosterone, and the IP3transient was more rapid than the fast calcium signal. Spironolactone, an inhibitor of the intracellular aldosterone receptor, or cyproterone acetate, an inhibitor of the testosterone receptor, had no effect on the fast [Ca2+]i signal or in the increase in IP3 mass. These signals could mean that there are distinct nongenomic pathways for the action of these two steroids in skeletal muscle cells.

Download Full-text

Faculty Opinions recommendation of Abnormalities of AMPK activation and glucose uptake in cultured skeletal muscle cells from individuals with chronic fatigue syndrome.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.725419785.793567529 ◽

2019 ◽

Author(s):

Yves Jammes

Keyword(s):

Skeletal Muscle ◽

Chronic Fatigue Syndrome ◽

Glucose Uptake ◽

Muscle Cells ◽

Chronic Fatigue ◽

Skeletal Muscle Cells ◽

Ampk Activation ◽

Fatigue Syndrome

Download Full-text

The Redox Homeostasis of Skeletal Muscle Cells Regulates Stage Differentiation of Toxoplasma gondii

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.798549 ◽

2021 ◽

Vol 11 ◽

Author(s):

Md. Taibur Rahman ◽

Izabela J. Swierzy ◽

Bryan Downie ◽

Gabriela Salinas ◽

Martin Blume ◽

...

Keyword(s):

Skeletal Muscle ◽

Toxoplasma Gondii ◽

Host Cell ◽

Redox Homeostasis ◽

Chronic Phase ◽

Tca Cycle ◽

Muscle Cells ◽

Pentose Phosphate ◽

Skeletal Muscle Cells ◽

Detoxification Enzymes

Toxoplasma gondii is an obligatory intracellular parasite that causes persistent infections in birds and mammals including ~30% of the world’s human population. Differentiation from proliferative and metabolically active tachyzoites to largely dormant bradyzoites initiates the chronic phase of infection and occurs predominantly in brain and muscle tissues. Here we used murine skeletal muscle cells (SkMCs) to decipher host cellular factors that favor T. gondii bradyzoite formation in terminally differentiated and syncytial myotubes, but not in proliferating myoblast precursors. Genome-wide transcriptome analyses of T. gondii-infected SkMCs and non-infected controls identified ~6,500 genes which were differentially expressed (DEGs) in myotubes compared to myoblasts, largely irrespective of infection. On the other hand, genes related to central carbohydrate metabolism, to redox homeostasis, and to the Nrf2-dependent stress response pathway were enriched in both infected myoblast precursors and myotubes. Stable isotope-resolved metabolite profiling indicated increased fluxes into the oxidative branch of the pentose phosphate pathway (OxPPP) in infected myoblasts and into the TCA cycle in infected myotubes. High OxPPP activity in infected myoblasts was associated with increased NADPH/NADP+ ratio while myotubes exhibited higher ROS levels and lower expression of anti-oxidants and detoxification enzymes. Pharmacological reduction of ROS levels in SkMCs inhibited bradyzoite differentiation, while increased ROS induced bradyzoite formation. Thus, we identified a novel host cell-dependent mechanism that triggers stage conversion of T. gondii into persistent tissue cysts in its natural host cell type.

Download Full-text