scholarly journals Acidic Compartment Size, Positioning, and Function during Myogenesis and Their Modulation by the Wnt/Beta-Catenin Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Kayo M. Bagri ◽  
Ivone A. Rosa ◽  
Stephany Corrêa ◽  
Aline Yamashita ◽  
José Brito ◽  
...  
Keyword(s):  
Primary Cultures ◽  
Muscle Cells ◽  
Beta Catenin ◽  
Inhibitory Effects ◽  
Lysosomal Function ◽  
Acidic Compartment ◽  
And Function ◽  
Cellular Compartments ◽  
Acidic Compartments

Lysosomes and acidic compartments are involved in breaking down of macromolecules, membrane recycling, and regulation of signaling pathways. Here, we analyzed the role of acidic compartments during muscle differentiation and the involvement of the Wnt/beta-catenin pathway in lysosomal function during myogenesis. Acridine orange was used to localize and quantify acidic cellular compartments in primary cultures of embryonic muscle cells from Gallus gallus. Our results show an increase in acidic compartment size and area, as well as changes in their positioning during the initial steps of myogenesis. The inhibition of lysosomal function by either the chloroquine Lys05 or the downregulation of LAMP-2 with siRNA impaired chick myogenesis, by inhibiting myoblast fusion. Two activators of the Wnt/beta-catenin pathway, BIO and Wnt3a, were able to rescue the inhibitory effects of Lys05 in myogenesis. These results suggest a new role for the Wnt/beta-catenin pathway in the regulation of acidic compartment size, positioning, and function in muscle cells.

scholarly journals Characterization and function of Ca2+-activated K+ channels in arteriolar muscle cells

1998 ◽  
Vol 274 (1) ◽  
pp. H27-H34 ◽  
Author(s):  
William F. Jackson ◽  
Kevin L. Blair
Keyword(s):  
Single Channel ◽  
Muscle Cells ◽  
Hill Coefficient ◽  
Apparent Lack ◽  
Maximal Activation ◽  
And Function ◽  
Resting Tone

We examined the functional role of large-conductance Ca2+-activated K+(KCa) channels in the hamster cremasteric microcirculation by intravital videomicroscopy and characterized the single-channel properties of these channels in inside-out patches of membrane from enzymatically isolated cremasteric arteriolar muscle cells. In second-order (39 ± 1 μm, n = 8) and third-order (19 ± 2 μm, n = 8) cremasteric arterioles with substantial resting tone, superfusion with the KCa channel antagonists tetraethylammonium (TEA, 1 mM) or iberiotoxin (IBTX, 100 nM) had no significant effect on resting diameters ( P > 0.05). However, TEA potentiated O2-induced arteriolar constriction in vivo, and IBTX enhanced norepinephrine-induced contraction of cremasteric arteriolar muscle cells in vitro. Patch-clamp studies revealed unitary K+-selective and IBTX-sensitive currents with a single-channel conductance of 240 ± 2 pS between −60 and 60 mV ( n = 7 patches) in a symmetrical 140 mM K+ gradient. The free Ca2+ concentration ([Ca2+]) for half-maximal channel activation was 44 ± 3, 20 ± 1, 6 ± 0.4, and 3 ± 0.5 μM at membrane potentials of −60, −30, +30, and +60 mV, respectively ( n = 5), with a Hill coefficient of 1.9 ± 0.2. Channel activity increased e-fold for a 16 ± 1 mV ( n = 6) depolarization. The plot of log[Ca2+] vs. voltage for half-maximal activation ( V ½) was linear ( r 2 = 0.9843, n = 6); the change in V ½ for a 10-fold change in [Ca2+] was 84 ± 5 mV, and the [Ca2+] for half-maximal activation at 0 mV (Ca0; the Ca2+ set point) was 9 μM. Thus, in vivo, KCa channels are silent in cremasteric arterioles at rest but can be recruited during vasoconstriction. We propose that the high Ca0 is responsible for the apparent lack of activity of these channels in resting cremasteric arterioles, and we suggest that this may result from expression of unique KCa channels in the microcirculation.

scholarly journals Inhibitory effects of cnidium components on proliferation of mouse aortic smooth muscle cells in primary cultures

1988 ◽  
Vol 46 ◽  
pp. 185
Author(s):  
Masayasu Kimura ◽  
Shinjiro Kobayashi ◽  
Kouhei Notoya ◽  
Yasuhiko Mimura ◽  
Jun Suzuki ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Primary Cultures ◽  
Muscle Cells ◽  
Inhibitory Effects ◽  
Aortic Smooth Muscle Cells ◽  
Aortic Smooth Muscle

scholarly journals Temporal expression and signalling of prostacyclin receptor in the human endometrium across the menstrual cycle

Reproduction ◽  
2004 ◽  
Vol 127 (1) ◽  
pp. 79-86 ◽  
Author(s):  
S Battersby ◽  
H O D Critchley ◽  
A J de Brum-Fernandes ◽  
H N Jabbour
Keyword(s):  
Menstrual Cycle ◽  
Human Endometrium ◽  
Menstrual Phase ◽  
Temporal Expression ◽  
Prostacyclin Receptor ◽  
Camp Generation ◽  
Ip Receptor ◽  
And Function ◽  
Cellular Compartments

Prostacyclin (PGI2) synthesis and function in the human uterus has been implicated in the regulation of the process of normal and dysfunctional menstruation. PGI2synthesis is elevated during normal menstruation and is also associated with blood loss in women who suffer from heavy menses. This study was designed to outline further the role of PGI2in menstruation by investigating the temporal pattern and site of expression of prostaglandin I synthase (PGIS) and the prostacyclin receptor (IP receptor) in the non-pregnant human endometrium across the menstrual cycle. Quantitative RT-PCR demonstrated increased expression of PGIS and IP receptor during the menstrual phase of the cycle compared with all other phases (P< 0.05). Furthermore, PGIS and IP receptor were localised to the glandular epithelium, stromal and endothelial cells in the basal and functional layers of the endometrium. Functionality of the IP receptor in the human endometrium was assessed by measuring cAMP generation following treatment with 100 nmol l−1of the PGI2analogue, iloprost. cAMP generation was significantly higher in endometrial tissue collected during the proliferative compared with the secretory phase of the menstrual cycle (P< 0.05).In conclusion, this study has confirmed increased expression and signalling of PGIS and IP receptor during the menstrual phase and outlines a potential autocrine/paracrine role for PGI2on several cellular compartments in the endometrium including the endothelium. This may underscore a pivotal role for PGI2receptor signalling in normal and dysfunctional menstruation.

scholarly journals Cilia in the developing zebrafish ear

2019 ◽  
Vol 375 (1792) ◽  
pp. 20190163 ◽  
Author(s):  
Tanya T. Whitfield
Keyword(s):  
Hair Cells ◽  
Otic Vesicle ◽  
Sensory Hair ◽  
Ciliary Motility ◽  
Extracellular Signals ◽  
Sensory Hair Cell ◽  
Sensory Hair Cells ◽  
And Function ◽  
Cellular Compartments

The inner ear, which mediates the senses of hearing and balance, derives from a simple ectodermal vesicle in the vertebrate embryo. In the zebrafish, the otic placode and vesicle express a whole suite of genes required for ciliogenesis and ciliary motility. Every cell of the otic epithelium is ciliated at early stages; at least three different ciliary subtypes can be distinguished on the basis of length, motility, genetic requirements and function. In the early otic vesicle, most cilia are short and immotile. Long, immotile kinocilia on the first sensory hair cells tether the otoliths, biomineralized aggregates of calcium carbonate and protein. Small numbers of motile cilia at the poles of the otic vesicle contribute to the accuracy of otolith tethering, but neither the presence of cilia nor ciliary motility is absolutely required for this process. Instead, otolith tethering is dependent on the presence of hair cells and the function of the glycoprotein Otogelin. Otic cilia or ciliary proteins also mediate sensitivity to ototoxins and coordinate responses to extracellular signals. Other studies are beginning to unravel the role of ciliary proteins in cellular compartments other than the kinocilium, where they are important for the integrity and survival of the sensory hair cell. This article is part of the Theo Murphy meeting issue ‘Unity and diversity of cilia in locomotion and transport’.

scholarly journals Estradiol increases cAMP in the oviductal secretory cells through a nongenomic mechanism

Reproduction ◽  
2014 ◽  
Vol 148 (3) ◽  
pp. 285-294 ◽  
Author(s):  
María L Oróstica ◽  
John Lopez ◽  
Israel Rojas ◽  
Jocelyn Rocco ◽  
Patricia Díaz ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Primary Cultures ◽  
Muscle Cells ◽  
Secretory Cells ◽  
Nongenomic Action ◽  
Confocal Immunofluorescence ◽  
Cellular Phenotypes ◽  
Egg Transport

In the rat oviduct, estradiol (E2) accelerates egg transport by a nongenomic action that requires previous conversion of E2to methoxyestrogens via catechol-O-methyltranferase (COMT) and activation of estrogen receptor (ER) with subsequent production of cAMP and inositol triphosphate (IP3). However, the role of the different oviductal cellular phenotypes on this E2nongenomic pathway remains undetermined. The aim of this study was to investigate the effect of E2on the levels of cAMP and IP3 in primary cultures of secretory and smooth muscle cells from rat oviducts and determine the mechanism by which E2increases cAMP in the secretory cells. In the secretory cells, E2increased cAMP but not IP3, while in the smooth muscle cells E2decreased cAMP and increased IP3. Suppression of protein synthesis by actinomycin D did not prevent the E2-induced cAMP increase, but this was blocked by the ER antagonist ICI 182 780 and the inhibitors of COMT OR 486, G protein-α inhibitory (Gαi) protein pertussis toxin and adenylyl cyclase (AC) SQ 22536. Expression of the mRNA for the enzymes that metabolizes estrogens,Comt,Cyp1a1, andCyp1b1was found in the secretory cells, but this was not affected by E2. Finally, confocal immunofluorescence analysis showed that E2induced colocalization between ESR1 (ERα) and Gαiin extranuclear regions of the secretory cells. We conclude that E2differentially regulates cAMP and IP3 in the secretory and smooth muscle cells of the rat oviduct. In the secretory cells, E2increases cAMP via a nongenomic action that requires activation of COMT and ER, coupling between ESR1 and Gαi, and stimulation of AC.

Potential role of insulin signaling on vascular smooth muscle cell migration, proliferation, and inflammation pathways

2012 ◽  
Vol 302 (4) ◽  
pp. C652-C657 ◽  
Author(s):  
Eugenio Cersosimo ◽  
Xiaojing Xu ◽  
Nicolas Musi
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Insulin Signaling ◽  
Primary Cultures ◽  
Muscle Cells ◽  
Mapk Signaling ◽  
Akt Phosphorylation ◽  
Erk Phosphorylation

To investigate the role of insulin signaling pathways in migration, proliferation, and inflammation of vascular smooth muscle cells (VSMCs), we examined the expression of active components of the phosphatidyl inositol 3 (PI-3) kinase (p-Akt) and mitogen-activated protein kinase (MAPK) (p-Erk) in primary cultures of VSMCs from human coronary arteries. VSMCs were treated in a dose-response manner with insulin (0, 1, 10, and 100 nM) for 20 min, and Akt and Erk phosphorylation were measured by Western blot analysis. In separate experiments, we evaluated the effect of 200 μM palmitate, in the presence and absence of 8 μM pioglitazone, on insulin-stimulated (100 nM for 20 min) Akt and Erk phosphorylation. The phosphorylation of Akt and Erk in VSMCs exhibited a dose dependency with a three- to fourfold increase, respectively, at the highest dose (100 nM). In the presence of palmitate, insulin-induced Akt phosphorylation was completely abolished, and there was a threefold increase in p-Erk. With addition of pioglitazone, the phosphorylation of Akt by insulin remained unchanged, whereas insulin-stimulated Erk phosphorylation was reduced by pioglitazone. These data in VSMCs indicate that high palmitate decreases insulin-stimulated Akt phosphorylation and stimulates MAPK, whereas preexposure peroxisome proliferator-activated receptor-γ agonist pioglitazone preserves Akt phosphorylation and simultaneously attenuates MAPK signaling. Our results suggest that metabolic and mitogenic insulin signals have different sensitivity, are independently regulated, and may play a role in arterial smooth muscle cells migration, proliferation, and inflammation in conditions of acute hyperinsulinemia.

scholarly journals Regulation of renal proximal tubule Na-K-ATPase by prostaglandins

2010 ◽  
Vol 298 (5) ◽  
pp. F1222-F1234 ◽  
Author(s):  
Maryann B. Herman ◽  
Trivikram Rajkhowa ◽  
Facundo Cutuli ◽  
James E. Springate ◽  
Mary Taub
Keyword(s):  
Proximal Tubule ◽  
Basolateral Membrane ◽  
Primary Cultures ◽  
Renal Proximal Tubule ◽  
Transcriptional Level ◽  
Mrna Levels ◽  
Inhibitory Effects ◽  
Α Subunit ◽  
Ep Receptors

Prostaglandins (PGs) play a number of roles in the kidney, including regulation of salt and water reabsorption. In this report, evidence was obtained for stimulatory effects of PGs on Na-K-ATPase in primary cultures of rabbit renal proximal tubule (RPT) cells. The results of our real-time PCR studies indicate that in primary RPTs the effects of PGE2, the major renal PG, are mediated by four classes of PGE (EP) receptors. The role of these EP receptors in the regulation of Na-K-ATPase was examined at the transcriptional level. Na-K-ATPase consists of a catalytic α-subunit encoded by the ATP1A1 gene, as well as a β-subunit encoded by the ATP1B1 gene. Transient transfection studies conducted with pHβ1-1141 Luc, a human ATP1B1 promoter/luciferase construct, indicate that both PGE1and PGE2are stimulatory. The evidence for the involvement of both the cAMP and Ca2+signaling pathways includes the inhibitory effects of the myristolylated PKA inhibitor PKI, the adenylate cyclase (AC) inhibitor SQ22536, and the PKC inhibitors Gö 6976 and Ro-32-0432 on the PGE1stimulation. Other effectors that similarly act through cAMP and PKC were also stimulatory to transcription, including norepinephrine and dopamine. In addition to its effects on transcription, a chronic incubation with PGE1was observed to result in an increase in Na-K-ATPase mRNA levels as well as an increase in Na-K-ATPase activity. An acute stimulatory effect of PGE1on Na-K-ATPase was observed and was associated with an increase in the level of Na-K-ATPase in the basolateral membrane.

scholarly journals The immune-inflammatory response of oligodendrocytes in a murine model of preterm white matter injury: the role of TLR3 activation

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Marta Boccazzi ◽  
Juliette Van Steenwinckel ◽  
Anne-Laure Schang ◽  
Valérie Faivre ◽  
Tifenn Le Charpentier ◽  
...  
Keyword(s):  
White Matter ◽  
Primary Cultures ◽  
White Matter Injury ◽  
Poly I:C ◽  
Cytokines And Chemokines ◽  
Wide Range ◽  
Preterm Born ◽  
And Function

AbstractA leading cause of preterm birth is the exposure to systemic inflammation (maternal/fetal infection), which leads to neuroinflammation and white matter injury (WMI). A wide range of cytokines and chemokines are expressed and upregulated in oligodendrocytes (OLs) in response to inflammation and numerous reports show that OLs express several receptors for immune related molecules, which enable them to sense inflammation and to react. However, the role of OL immune response in WMI is unclear. Here, we focus our study on toll-like receptor-3 (TLR3) that is activated by double-strand RNA (dsRNA) and promotes neuroinflammation. Despite its importance, its expression and role in OLs remain unclear. We used an in vivo mouse model, which mimics inflammation-mediated WMI of preterm born infants consisting of intraperitoneal injection of IL-1β from P1 to P5. In the IL-1β-treated animals, we observed the upregulation of Tlr3, IL-1β, IFN-β, Ccl2, and Cxcl10 in both PDGFRα+ and O4+ sorted cells. This upregulation was higher in O4+ immature OLs (immOLs) as compared to PDGFRα+ OL precursor cells (OPCs), suggesting a different sensitivity to neuroinflammation. These observations were confirmed in OL primary cultures: cells treated with TLR3 agonist Poly(I:C) during differentiation showed a stronger upregulation of Ccl2 and Cxcl10 compared to cells treated during proliferation and led to decreased expression of myelin genes. Finally, OLs were able to modulate microglia phenotype and function depending on their maturation state as assessed by qPCR using validated markers for immunomodulatory, proinflammatory, and anti-inflammatory phenotypes and by phagocytosis and morphological analysis. These results show that during inflammation the response of OLs can play an autonomous role in blocking their own differentiation: in addition, the immune activation of OLs may play an important role in shaping the response of microglia during inflammation.

scholarly journals Branched-chain ketoacid overload inhibits insulin action in the muscle

2020 ◽  
Vol 295 (46) ◽  
pp. 15597-15621 ◽  
Author(s):  
Dipsikha Biswas ◽  
Khoi T. Dao ◽  
Angella Mercer ◽  
Andrew M. Cowie ◽  
Luke Duffley ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Insulin Signaling ◽  
Muscle Cells ◽  
Protein Translation ◽  
Ultra Performance Liquid Chromatography ◽  
Enzyme Expression ◽  
Akt Phosphorylation ◽  
Branched Chain ◽  
And Function

Branched-chain α-keto acids (BCKAs) are catabolites of branched-chain amino acids (BCAAs). Intracellular BCKAs are cleared by branched-chain ketoacid dehydrogenase (BCKDH), which is sensitive to inhibitory phosphorylation by BCKD kinase (BCKDK). Accumulation of BCKAs is an indicator of defective BCAA catabolism and has been correlated with glucose intolerance and cardiac dysfunction. However, it is unclear whether BCKAs directly alter insulin signaling and function in the skeletal and cardiac muscle cell. Furthermore, the role of excess fatty acids (FAs) in perturbing BCAA catabolism and BCKA availability merits investigation. By using immunoblotting and ultra-performance liquid chromatography MS/MS to analyze the hearts of fasted mice, we observed decreased BCAA-catabolizing enzyme expression and increased circulating BCKAs, but not BCAAs. In mice subjected to diet-induced obesity (DIO), we observed similar increases in circulating BCKAs with concomitant changes in BCAA-catabolizing enzyme expression only in the skeletal muscle. Effects of DIO were recapitulated by simulating lipotoxicity in skeletal muscle cells treated with saturated FA, palmitate. Exposure of muscle cells to high concentrations of BCKAs resulted in inhibition of insulin-induced AKT phosphorylation, decreased glucose uptake, and mitochondrial oxygen consumption. Altering intracellular clearance of BCKAs by genetic modulation of BCKDK and BCKDHA expression showed similar effects on AKT phosphorylation. BCKAs increased protein translation and mTORC1 activation. Pretreating cells with mTORC1 inhibitor rapamycin restored BCKA's effect on insulin-induced AKT phosphorylation. This study provides evidence for FA-mediated regulation of BCAA-catabolizing enzymes and BCKA content and highlights the biological role of BCKAs in regulating muscle insulin signaling and function.

scholarly journals On the role of tubulin, plectin, desmin, and vimentin in the regulation of mitochondrial energy fluxes in muscle cells

2019 ◽  
Vol 316 (5) ◽  
pp. C657-C667 ◽  
Author(s):  
Kati Mado ◽  
Vladimir Chekulayev ◽  
Igor Shevchuk ◽  
Marju Puurand ◽  
Kersti Tepp ◽  
...  
Keyword(s):  
Striated Muscle ◽  
Adenine Nucleotides ◽  
Anion Channel ◽  
Muscle Cells ◽  
Eukaryotic Cell ◽  
Cytoskeletal Proteins ◽  
Energy Fluxes ◽  
Voltage Dependent Anion Channel ◽  
And Function

Mitochondria perform a central role in life and death of the eukaryotic cell. They are major players in the generation of macroergic compounds and function as integrated signaling pathways, including the regulation of Ca2+ signals and apoptosis. A growing amount of evidence is demonstrating that mitochondria of muscle cells use cytoskeletal proteins (both microtubules and intermediate filaments) not only for their movement and proper cellular positioning, but also to maintain their biogenesis, morphology, function, and regulation of energy fluxes through the outer mitochondrial membrane (MOM). Here we consider the known literature data concerning the role of tubulin, plectin, desmin and vimentin in bioenergetic function of mitochondria in striated muscle cells, as well as in controlling the permeability of MOM for adenine nucleotides (ADNs). This is of great interest since dysfunctionality of these cytoskeletal proteins has been shown to result in severe myopathy associated with pronounced mitochondrial dysfunction. Further efforts are needed to uncover the pathways by which the cytoskeleton supports the functional capacity of mitochondria and transport of ADN(s) across the MOM (through voltage-dependent anion channel).

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