scholarly journals Biological Redox Impact of Tocopherol Isomers Is Mediated by Fast Cytosolic Calcium Increases in Living Caco-2 Cells

Antioxidants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 155
Author(s):  
Miltha Hidalgo ◽  
Vania Rodríguez ◽  
Christine Kreindl ◽  
Omar Porras
Keyword(s):  
Plasma Membrane ◽  
Cellular Responses ◽  
Cytosolic Calcium ◽  
Tetraacetic Acid ◽  
Cellular Mechanisms ◽  
Fast Kinetics ◽  
Antioxidant Responses ◽  
Biological Impacts ◽  
Monensin A ◽  
Tocopherol Isomers

Most of the biological impacts of Vitamin E, including the redox effects, have been raised from studies with α-tocopherol only, despite the fact that tocopherol-containing foods carry mixed tocopherol isomers. Here, we investigated the cellular mechanisms involved in the immediate antioxidant responses evoked by α-, γ- and δ-tocopherol in Caco-2 cells. In order to track the cytosolic redox impact, we performed imaging on cells expressing HyPer, a fluorescent redox biosensor, while cytosolic calcium fluctuations were monitored by means of Fura-2 dye and imaging. With this approach, we could observe fast cellular responses evoked by the addition of α-, γ- and δ-tocopherol at concentrations as low as 2.5 μM. Each isomer induced rapid and consistent increases in cytosolic calcium with fast kinetics, which were affected by chelation of extracellular Ca2+, suggesting that tocopherols promoted a calcium entry upon the contact with the plasma membrane. In terms of redox effects, δ-tocopherol was the only isomer that evoked a significant change in the HyPer signal at 5 μM. By mimicking Ca2+ entry with ionomycin and monensin, a decline in the HyPer signal was induced as well. Finally, by silencing calcium with 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA), an intracellular Ca2+ chelator, none of the isomers were able to induce redox changes. Altogether, our data indicate that an elevation in cytoplasmic Ca2+ is necessary for the development of a tocopherol-induced antioxidant impact on the cytoplasm of Caco-2 cells reported by HyPer biosensor.

Regulation of intracellular free calcium in normal murine keratinocytes

1991 ◽  
Vol 261 (5) ◽  
pp. C767-C773 ◽  
Author(s):  
F. H. Kruszewski ◽  
H. Hennings ◽  
S. H. Yuspa ◽  
R. W. Tucker
Keyword(s):  
Image Analysis ◽  
Plasma Membrane ◽  
Digital Image Analysis ◽  
Cellular Responses ◽  
Cytosolic Calcium ◽  
Dermal Fibroblasts ◽  
Cell Phenotype ◽  
Free Calcium ◽  
Serum Response ◽  
Initial Peak

Cultured normal murine keratinocytes maintain a basal cell phenotype in medium with a Ca2+ concentration of 0.05 mM and differentiate when exposed for 28-48 h to medium supplemented with extracellular Ca2+ greater than 0.10 mM. Previous studies have documented Ca2+ activation of signaling pathways in the plasma membrane and tightly regulated cellular responses to small incremental changes in extracellular Ca2+. To determine if changes in free cytosolic calcium (Cai) are associated with these early signaling events, digital image analysis of fura-2-loaded keratinocytes was used to measure Cai in individual cells. Basal keratinocytes in 0.05 mM Ca2+ display a biphasic Cai increase when exposed to greater than 0.1 mM Ca2+ in serum-containing medium. These separate phases were controlled by different media components. Initial peak Cai occurred rapidly (within 60 s), was transient (lasting less than 5 min), and resulted from release of 10-20% of total intracellular Ca2+ stores. Peak Cai depended on serum concentration and was independent of extracellular Ca2+. This transient Cai response was lost as keratinocytes differentiated. Plateau Cai level was sustained (greater than 24 h) and depended on extracellular Ca2+, but not serum. The magnitude of plateau Cai increased incrementally following increases in extracellular Ca2+ as small as 0.02 mM. A similar biphasic Cai increase was noted in cultures of murine dermal fibroblasts stimulated by 1.2 mM Ca2+ and serum. However, fibroblasts did not lose the serum response in high-Ca2+ medium, and plateau Cai was not sensitive to small changes in extracellular Ca2+.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Regulation of Neural Cell Adhesion Molecule Polysialylation: Evidence for Nontranscriptional Control and Sensitivity to an Intracellular Pool of Calcium

1998 ◽  
Vol 140 (5) ◽  
pp. 1177-1186 ◽  
Author(s):  
Juan L. Brusés ◽  
Urs Rutishauser
Keyword(s):  
Cell Adhesion ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Neural Cell Adhesion Molecule ◽  
Calcium Ionophore ◽  
Cytosolic Calcium ◽  
Neural Cell ◽  
Ciliary Ganglion ◽  
Cellular Mechanisms ◽  
Neural Cell Adhesion

The up- and downregulation of polysialic acid–neural cell adhesion molecule (PSA–NCAM) expression on motorneurons during development is associated respectively with target innervation and synaptogenesis, and is regulated at the level of PSA enzymatic biosynthesis involving specific polysialyltransferase activity. The purpose of this study has been to describe the cellular mechanisms by which that regulation might occur. It has been found that developmental regulation of PSA synthesis by ciliary ganglion motorneurons is not reflected in the levels of polysialyltransferase-1 (PST) or sialyltransferase-X (STX) mRNA. On the other hand, PSA synthesis in both the ciliary ganglion and the developing tectum appears to be coupled to the concentration of calcium in intracellular compartments. This study documents a calcium dependence of polysialyltransferase activity in a cell-free assay over the range of 0.1–1 mM, and a rapid sensitivity of new PSA synthesis, as measured in a pulse–chase analysis of tissue explants, to calcium ionophore perturbation of intracellular calcium levels. Moreover, the relevant calcium pool appears to be within a specific intracellular compartment that is sensitive to thapsigargin and does not directly reflect the level of cytosolic calcium. Perturbation of other major second messenger systems, such as cAMP and protein kinase–dependent pathways, did not affect polysialylation in the pulse chase analysis. These results suggest that the shuttling of calcium to different pools within the cell can result in the rapid regulation of PSA synthesis in developing tissues.

scholarly journals The poly(ADP-ribose)-dependent chromatin remodeler Alc1 induces local chromatin relaxation upon DNA damage

2016 ◽  
Vol 27 (24) ◽  
pp. 3791-3799 ◽  
Author(s):  
Hafida Sellou ◽  
Théo Lebeaupin ◽  
Catherine Chapuis ◽  
Rebecca Smith ◽  
Anna Hegele ◽  
...  
Keyword(s):  
Dna Damage ◽  
Structural Changes ◽  
Cellular Responses ◽  
Dna Lesions ◽  
Fast Kinetics ◽  
Important Player ◽  
Chromatin Relaxation ◽  
Kinetics Of ◽  
Laser Microirradiation

Chromatin relaxation is one of the earliest cellular responses to DNA damage. However, what determines these structural changes, including their ATP requirement, is not well understood. Using live-cell imaging and laser microirradiation to induce DNA lesions, we show that the local chromatin relaxation at DNA damage sites is regulated by PARP1 enzymatic activity. We also report that H1 is mobilized at DNA damage sites, but, since this mobilization is largely independent of poly(ADP-ribosyl)ation, it cannot solely explain the chromatin relaxation. Finally, we demonstrate the involvement of Alc1, a poly(ADP-ribose)- and ATP-dependent remodeler, in the chromatin-relaxation process. Deletion of Alc1 impairs chromatin relaxation after DNA damage, while its overexpression strongly enhances relaxation. Altogether our results identify Alc1 as an important player in the fast kinetics of the NAD+- and ATP-dependent chromatin relaxation upon DNA damage in vivo.

Modulation of frequency and height of cytosolic calcium spikes by plasma membrane anion channels in guard cells

2021 ◽  
Author(s):  
Md Tahjib-Ul-Arif ◽  
Shintaro Munemasa ◽  
Toshiyuki Nakamura ◽  
Yoshimasa Nakamura ◽  
Yoshiyuki Murata
Keyword(s):  
Plasma Membrane ◽  
Stomatal Closure ◽  
Anion Channel ◽  
Guard Cells ◽  
Cytosolic Calcium ◽  
Peak Height ◽  
Extracellular Calcium ◽  
Wild Type ◽  
Anion Channels ◽  
In The Wild

Abstract Cytosolic calcium ([Ca2+]cyt) elevation activates plasma membrane anion channels in guard cells, which is required for stomatal closure. However, involvement of the anion channels in the [Ca2+]cyt elevation remains unclear. We investigated the involvement using Arabidopsis thaliana anion channel mutants, slac1-4 slah3-3 and slac1-4 almt12-1. Extracellular calcium induced stomatal closure in the wild-type plants but not in the anion channel mutant plants whereas extracellular calcium induced [Ca2+]cyt elevation both in the wild-type guard cells and in the mutant guard cells. The peak height and the number of the [Ca2+]cyt spike were lower and larger in the slac1-4 slah3-3 than in the wild-type and the height and the number in the slac1-4 almt12-1 were much lower and much larger than in the wild-type. These results suggest that the anion channels are involved in the regulation of [Ca2+]cyt elevation in guard cells.

Extracellular vesicle interplay in cardiovascular pathophysiology

2021 ◽  
Author(s):  
Sherin Saheera ◽  
Vivek P Jani ◽  
Kenneth W Witwer ◽  
Shelby Kutty
Keyword(s):  
Plasma Membrane ◽  
Cardiovascular System ◽  
Lipid Bilayer ◽  
Cellular Responses ◽  
Extracellular Vesicle ◽  
Cargo Proteins ◽  
And Function ◽  
Intercellular Communications ◽  
Rna And Dna

Extracellular vesicles (EVs) are nanosized lipid bilayer-delimited particles released from cells that mediate intercellular communications and play a pivotal role in various physiological and pathological processes. Subtypes of EVs may include plasma-membrane ectosomes or microvesicles and endosomal-origin exosomes, although functional distinctions remain unclear. EVs carry cargo proteins, nucleic acids (RNA and DNA), lipids, and metabolites. By presenting or transferring this cargo to recipient cells, EVs can trigger cellular responses. Here, we summarize what is known about EV biogenesis, composition, and function, with an emphasis on the role of EVs in cardiovascular system. Additionally, we provide an update on the function of EVs in cardiovascular pathophysiology, further highlighting their potential for diagnostic and therapeutic applications.

ADP-ribose gates the fertilization channel in ascidian oocytes

1998 ◽  
Vol 275 (5) ◽  
pp. C1277-C1283 ◽  
Author(s):  
Martin Wilding ◽  
Gian Luigi Russo ◽  
Anthony Galione ◽  
Marcella Marino ◽  
Brian Dale
Keyword(s):  
Plasma Membrane ◽  
Ion Channel ◽  
Reversal Potential ◽  
Ciona Intestinalis ◽  
Second Messenger ◽  
Tetraacetic Acid ◽  
Independent Manner ◽  
Unitary Conductance ◽  
Intracellular Ca ◽  
Hydrolysis Of

We report an ion channel in the plasma membrane of unfertilized oocytes of the ascidian Ciona intestinalis that is directly gated by the second messenger ADP-ribose. The ion channel is permeable to Ca2+ and Na+ and is characterized by a reversal potential between 0 and +20 mV and a unitary conductance of 140 pS. Preinjection of the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane- N, N, N′, N′-tetraacetic acid (BAPTA) or antagonists of intracellular Ca2+ release channels into oocytes did not inhibit the ADP-ribose current, demonstrating that the channel is activated in a Ca2+-independent manner. Both the fertilization current and the current induced by the injection of nicotinamide nucleotides are blocked by nicotinamide, suggesting that the ADP-ribose channel is activated at fertilization in a nicotinamide-sensitive manner. These data suggest that ascidian sperm trigger the hydrolysis of nicotinamide nucleotides in the oocyte to ADP-ribose and that this mechanism is responsible for the production of the fertilization current.

scholarly journals Mecanismos de tolerancia a elementos potencialmente tóxicos en plantas

2017 ◽  
pp. 53 ◽  
Author(s):  
Daniel González-Mendoza ◽  
Omar Zapata-Pérez
Keyword(s):  
Heavy Metals ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Toxic Elements ◽  
Potentially Toxic Elements ◽  
Free Proline ◽  
Potentially Toxic Metals ◽  
Cellular Mechanisms ◽  
Mycorrhizal Associations ◽  
Broad Overview

Plants possess a wide array of potential cellular mechanisms that may be involved in the tolerance to potentially toxic elements. These mechanisms include mycorrhizal associations, heavy metals binding to cell wall, precipitation by extracellular exudates; reduction in uptake or efflux pumping of metals at the plasma membrane, chelation of metals in the cytosol by peptides such as phytochelatins, metallothionein, histidina free, proline free , and the compartmentation of metals in the vacuole by tono-plast- located transporters. This review provides a broad overview of the evidence of the involvement of each mechanism in plants' tolerance to potentially toxic metals.

scholarly journals Insulin Protects Pancreatic Acinar Cells from Cytosolic Calcium Overload and Inhibition of Plasma Membrane Calcium Pump

2011 ◽  
Vol 287 (3) ◽  
pp. 1823-1836 ◽  
Author(s):  
Parini Mankad ◽  
Andrew James ◽  
Ajith K. Siriwardena ◽  
Austin C. Elliott ◽  
Jason I. E. Bruce
Keyword(s):  
Plasma Membrane ◽  
Acinar Cells ◽  
Cytosolic Calcium ◽  
Calcium Overload ◽  
Calcium Pump ◽  
Pancreatic Acinar Cells ◽  
Plasma Membrane Calcium Pump

The third intracellular loop and carboxyl tail of neurokinin 1 and 3 receptors determine interactions with β-arrestins

2003 ◽  
Vol 285 (4) ◽  
pp. C945-C958 ◽  
Author(s):  
Fabien Schmidlin ◽  
Dirk Roosterman ◽  
Nigel W. Bunnett
Keyword(s):  
Plasma Membrane ◽  
Map Kinases ◽  
Cellular Responses ◽  
Receptor Desensitization ◽  
Intracellular Loop ◽  
Neurokinin Receptors ◽  
Selective Agonist ◽  
Third Intracellular Loop ◽  
Neurokinin 1 ◽  
Carboxyl Tail

Tachykinins interact with three neurokinin receptors (NKRs) that are often coexpressed by the same cell. Cellular responses to tachykinins depend on the NKR subtype that is activated. We compared the colocalization of NK1R and NK3R with β-arrestins 1 and 2, which play major roles in receptor desensitization, endocytosis, and signaling. In cells expressing NK1R, the selective agonist Sar-Met-substance P induced rapid translocation of β-arrestins 1 and 2 from the cytosol to the plasma membrane and then endosomes, indicative of interaction with both isoforms. In contrast, the NK3R interacted transiently with only β-arrestin 2 at the plasma membrane. Despite these differences, both NK1R and NK3R similarly desensitized, internalized, and activated MAP kinases. Because interactions with β-arrestins can explain differences in the rate of receptor resensitization, we compared resensitization of agonist-induced Ca2+ mobilization. The NK1R resensitized greater than twofold more slowly than the NK3R. Replacement of intracellular loop 3 and the COOH tail of the NK1R with comparable domains of the NK3R diminished colocalization of the NK1R with β-arrestin 1 and accelerated resensitization to that of the NK3R. Thus loop 3 and the COOH tail specify colocalization of the NK1R with β-arrestin 1 and determine the rate of resensitization.

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