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Ha CM, Kim DH, Lee TH, Kim HR, Choi J, Kim Y, Kang D, Park JW, Ojeda SR, Jeong JK, Lee BJ. Transcriptional Regulatory Role of NELL2 in Preproenkephalin Gene Expression. Mol Cells 2022; 45:537-549. [PMID: 35950455 PMCID: PMC9385569 DOI: 10.14348/molcells.2022.2051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 03/28/2022] [Accepted: 04/03/2022] [Indexed: 12/23/2022] Open
Abstract
Preproenkephalin (PPE) is a precursor molecule for multiple endogenous opioid peptides Leu-enkephalin (ENK) and Met-ENK, which are involved in a wide variety of modulatory functions in the nervous system. Despite the functional importance of ENK in the brain, the effect of brain-derived factor(s) on PPE expression is unknown. We report the dual effect of neural epidermal growth factor (EGF)-likelike 2 (NELL2) on PPE gene expression. In cultured NIH3T3 cells, transfection of NELL2 expression vectors induced an inhibition of PPE transcription intracellularly, in parallel with downregulation of protein kinase C signaling pathways and extracellular signal-regulated kinase. Interestingly, these phenomena were reversed when synthetic NELL2 was administered extracellularly. The in vivo disruption of NELL2 synthesis resulted in an increase in PPE mRNA level in the rat brain, suggesting that the inhibitory action of intracellular NELL2 predominates the activation effect of extracellular NELL2 on PPE gene expression in the brain. Biochemical and molecular studies with mutant NELL2 structures further demonstrated the critical role of EGF-like repeat domains in NELL2 for regulation of PPE transcription. These are the first results to reveal the spatio-specific role of NELL2 in the homeostatic regulation of PPE gene expression.
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Affiliation(s)
- Chang Man Ha
- Brain Research Core Facilities and Global Relation Center of Research Strategy Office, Korea Brain Research Institute, Daegu 41068, Korea
| | - Dong Hee Kim
- Department of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Tae Hwan Lee
- Department of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Han Rae Kim
- Department of Pharmacology and Physiology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | - Jungil Choi
- Bioenvironmental Science & Technology Division, Korea Institute of Toxicology, Jinju 52834, Korea
| | - Yoonju Kim
- Brain Research Core Facilities and Global Relation Center of Research Strategy Office, Korea Brain Research Institute, Daegu 41068, Korea
| | - Dasol Kang
- Department of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Jeong Woo Park
- Department of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Sergio R. Ojeda
- Division of Neuroscience, Oregon National Primate Research Center/Oregon Health & Science University, Beaverton, OR 97006, USA
| | - Jin Kwon Jeong
- Department of Pharmacology and Physiology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | - Byung Ju Lee
- Department of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
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Roberts RE, Vervliet T, Bultynck G, Parys JB, Hallett MB. EPIC3, a novel Ca 2+ indicator located at the cell cortex and in microridges, detects high Ca 2+ subdomains during Ca 2+ influx and phagocytosis. Cell Calcium 2020; 92:102291. [PMID: 33099169 DOI: 10.1016/j.ceca.2020.102291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/11/2020] [Accepted: 09/17/2020] [Indexed: 11/15/2022]
Abstract
The construction of a low affinity Ca2+-probe that locates to the cell cortex and cell surface wrinkles, is described called. EPIC3 (ezrin-protein indicator of Ca2+). The novel probe is a fusion of CEPIA3 with ezrin, and is used in combination with a Ca2+-insensitive probe, ezrin-mCherry, both of which locate at the cell cortex. EPIC3 was used to monitor the effect of Ca2+ influx on intra-wrinkle Ca2+ in the macrophage cell line, RAW 264.7. During experimentally-induced Ca2+influx, EPIC3 reported Ca2+ concentrations at the cell cortex in the region of 30-50 μM, with peak locations towards the tips of wrinkles reaching 80 μM. These concentrations were associated with cleavage of ezrin (a substrate for the Ca2+ activated protease calpain-1) and released the C-terminal fluors. The cortical Ca2+ levels, restricted to near the site of phagocytic cup formation and pseudopodia extension during phagocytosis also reached high levels (50-80 μM) during phagocytosis. As phagocytosis was completed, hotspots of Ca2+ near the phagosome were also observed.
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Affiliation(s)
- Rhiannon E Roberts
- Neutrophil Signalling Group, Cardiff University Medical School, Cardiff, CF14 4XN, UK
| | - Tim Vervliet
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Jan B Parys
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Maurice B Hallett
- Neutrophil Signalling Group, Cardiff University Medical School, Cardiff, CF14 4XN, UK.
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3
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Feng M, Elaïb Z, Borgel D, Denis CV, Adam F, Bryckaert M, Rosa JP, Bobe R. NAADP/SERCA3-Dependent Ca 2+ Stores Pathway Specifically Controls Early Autocrine ADP Secretion Potentiating Platelet Activation. Circ Res 2020; 127:e166-e183. [PMID: 32588751 DOI: 10.1161/circresaha.119.316090] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Ca2+ signaling is a key and ubiquitous actor of cell organization and its modulation controls many cellular responses. SERCAs (sarco-endoplasmic reticulum Ca2+-ATPases) pump Ca2+ into internal stores that play a major role in the cytosolic Ca2+ concentration rise upon cell activation. Platelets exhibit 2 types of SERCAs, SERCA2b and SERCA3 (SERCA3 deficient mice), which may exert specific roles, yet ill-defined. We have recently shown that Ca2+ mobilization from SERCA3-dependent stores was required for full platelet activation in weak stimulation conditions. OBJECTIVE To uncover the signaling mechanisms associated with Ca2+ mobilization from SERCA3-dependent stores leading to ADP secretion. METHODS AND RESULTS Using platelets from wild-type or Serca3-deficient mice, we demonstrated that an early (within 5-10 s following stimulation) secretion of ADP specifically dependent on SERCA3 stored Ca2+ is exclusively mobilized by nicotinic acid adenosine dinucleotide-phosphate (NAADP): both Ca2+ mobilization from SERCA3-dependent stores and primary ADP secretion are blocked by the NAADP receptor antagonist Ned-19, and reciprocally both are stimulated by permeant NAADP. In contrast, Ca2+ mobilization from SERCA3-dependent stores and primary ADP secretion were unaffected by inhibition of the production of IP3 (inositol-1,4,5-trisphosphate) by phospholipase-C and accordingly were not stimulated by permeant IP3. CONCLUSIONS Upon activation, an NAADP/SERCA3 Ca2+ mobilization pathway initiates an early ADP secretion, potentiating platelet activation, and a secondary wave of ADP secretion driven by both an IP3/SERCA2b-dependent Ca2+ stores pathway and the NAADP/SERCA3 pathway. This does not exclude that Ca2+ mobilized from SERCA3 stores may also enhance platelet global reactivity to agonists. Because of its modulating effect on platelet activation, this NAADP-SERCA3 pathway may be a relevant target for anti-thrombotic therapy. Graphic Abstract: A graphic abstract is available for this article.
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Affiliation(s)
- Miao Feng
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Ziane Elaïb
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Delphine Borgel
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Cécile V Denis
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Frédéric Adam
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Marijke Bryckaert
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Jean-Philippe Rosa
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Régis Bobe
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
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4
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Hallett MB, Roberts RE, Dewitt S. Optical Methods for the Measurement and Manipulation of Cytosolic Calcium Signals in Neutrophils. Methods Mol Biol 2020; 2087:191-205. [PMID: 31728992 DOI: 10.1007/978-1-0716-0154-9_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The measurement and manipulation of cytosolic free Ca2+ of neutrophils is crucial for investigating the mechanisms within living neutrophils which generate Ca2+ signals and the cellular responses triggered by them. Optical methods for this are the most applicable for neutrophils, and are discussed here, especially the use of fluorescent indicators of Ca2+ and photoactivation of reagents involved in Ca2+ signaling. Both of these synthetic agents can be loaded into neutrophils as lipid-soluble esters or can be microinjected into the cell. In this chapter, we outline some of the techniques that have been used to monitor, visualize, and manipulate Ca2+ in neutrophils.
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Affiliation(s)
| | | | - Sharon Dewitt
- School of Medicine and School of Dentistry, Cardiff University, Cardiff, UK
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5
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Calpain Activation by Ca2+ and Its Role in Phagocytosis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1246:129-151. [DOI: 10.1007/978-3-030-40406-2_8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Neutrophil Cell Shape Change: Mechanism and Signalling during Cell Spreading and Phagocytosis. Int J Mol Sci 2019; 20:ijms20061383. [PMID: 30893856 PMCID: PMC6471475 DOI: 10.3390/ijms20061383] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 03/12/2019] [Accepted: 03/14/2019] [Indexed: 12/16/2022] Open
Abstract
Perhaps the most important feature of neutrophils is their ability to rapidly change shape. In the bloodstream, the neutrophils circulate as almost spherical cells, with the ability to deform in order to pass along narrower capillaries. Upon receiving the signal to extravasate, they are able to transform their morphology and flatten onto the endothelium surface. This transition, from a spherical to a flattened morphology, is the first key step which neutrophils undergo before moving out of the blood and into the extravascular tissue space. Once they have migrated through tissues towards sites of infection, neutrophils carry out their primary role-killing infecting microbes by performing phagocytosis and producing toxic reactive oxygen species within the microbe-containing phagosome. Phagocytosis involves the second key morphology change that neutrophils undergo, with the formation of pseudopodia which capture the microbe within an internal vesicle. Both the spherical to flattened stage and the phagocytic capture stage are rapid, each being completed within 100 s. Knowing how these rapid cell shape changes occur in neutrophils is thus fundamental to understanding neutrophil behaviour. This article will discuss advances in our current knowledge of this process, and also identify an important regulated molecular event which may represent an important target for anti-inflammatory therapy.
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7
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Active calpain in phagocytically competent human neutrophils: electroinjection of fluorogenic calpain substrate. Biochem Biophys Res Commun 2015; 457:341-6. [PMID: 25576867 DOI: 10.1016/j.bbrc.2014.12.113] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 12/26/2014] [Indexed: 11/20/2022]
Abstract
Calpain has been implicated in the apparent expansion of neutrophil plasma membrane that accompanies cell spreading and phagocytosis. In order to test this hypothesis, an internally quenched fluorescent peptide substrate of calpain-1 which increased in fluorescence on cleavage, was micro-electroinjected into neutrophils. The fluorescence intensity increased in a significant number of neutrophils, including those which appeared to be in a morphologically resting (spherical) state. In order to test whether calpain was activated by an elevation of cytosolic Ca(2+) during the injection, Ca(2+) chelators were added to the injectate and cytosolic free Ca(2+) in the receiving neutrophil was simultaneously monitored. It was shown that this approach could be used without raising Ca(2+) within the injected cell. Despite this, approximately 75% of individual neutrophils had calpain activity which consumed the substrate within approx. 100 s. It was found that all neutrophils had elevated calpain activity were phagocytically competent; whereas neutrophils with low or undetectable calpain activity failed to undergo phagocytosis. This association was consistent with the hypothesis that calpain activity within neutrophils was necessary for them to undergo efficient phagocytosis.
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8
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Lewis KJ, Masterman B, Laffafian I, Dewitt S, Campbell JS, Hallett MB. Minimal impact electro-injection of cells undergoing dynamic shape change reveals calpain activation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:1182-7. [PMID: 24607452 DOI: 10.1016/j.bbamcr.2014.02.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 02/09/2014] [Accepted: 02/28/2014] [Indexed: 10/25/2022]
Abstract
The ability of neutrophils to rapidly change shape underlies their physiological functions of phagocytosis and spreading. A major problem in establishing the mechanism is that conventional microinjection of substances and indicators interferes with this dynamic cell behaviour. Here we show that electroinjection, a "no-touch" point-and-shoot means of introducing material into the cell, is sufficiently gentle to allow neutrophils to be injected whilst undergoing chemokinesis and spreading without disturbing cell shape change behaviour. Using this approach, a fluorogenic calpain-1 selective peptide substrate was introduced into the cytosol of individual neutrophils undergoing shape changes. These data showed that (i) physiologically elevated cytosolic Ca(2+) concentrations were sufficient to trigger calpain-1 activation, blockade of Ca(2+) influx preventing calpain activation and (ii) calpain-1 activity was elevated in spreading neutrophil. These findings provide the first direct demonstration of a physiological role for Ca(2+) elevation in calpain-1 activation and rapid cell spreading. Electroinjection of cells undergoing dynamic shape changes thus opens new avenues of investigation for defining the molecular mechanism underlying dynamic cell shape changes.
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Affiliation(s)
- Kimberley J Lewis
- Neutrophil Signalling Group, Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Heath Park, Cardiff University, Cardiff CF14 4XN, UK
| | - Benjamin Masterman
- Neutrophil Signalling Group, Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Heath Park, Cardiff University, Cardiff CF14 4XN, UK
| | - Iraj Laffafian
- Neutrophil Signalling Group, Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Heath Park, Cardiff University, Cardiff CF14 4XN, UK
| | - Sharon Dewitt
- School of Dentistry, Cardiff University, Heath Park, Cardiff University, Cardiff CF14 4XN, UK
| | - Jennie S Campbell
- Neutrophil Signalling Group, Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Heath Park, Cardiff University, Cardiff CF14 4XN, UK
| | - Maurice B Hallett
- Neutrophil Signalling Group, Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Heath Park, Cardiff University, Cardiff CF14 4XN, UK.
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9
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Optical methods for the measurement and manipulation of cytosolic calcium signals in neutrophils. Methods Mol Biol 2014. [PMID: 24504949 DOI: 10.1007/978-1-62703-845-4_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The measurement and manipulation of cytosolic free Ca(2+) of neutrophils is crucial for investigating the mechanisms within living neutrophils which generate Ca(2+) signals and the cellular responses triggered by them. Optical methods for this are the most applicable for neutrophils and are discussed here, especially the use of fluorescent indicators of Ca(2+) and photoactivation of reagents involved in Ca(2+) signaling. Both of these synthetic agents can be loaded into neutrophils as lipid-soluble esters or can be microinjected into the cell. In this chapter, we will outline some of the techniques that have been used to monitor, visualize, and manipulate Ca(2+) in neutrophils.
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10
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Brasen JC, Olsen LF, Hallett MB. Cell surface topology creates high Ca2+ signalling microdomains. Cell Calcium 2010; 47:339-49. [PMID: 20153895 PMCID: PMC2877796 DOI: 10.1016/j.ceca.2010.01.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 01/20/2010] [Accepted: 01/21/2010] [Indexed: 12/01/2022]
Abstract
It has long been speculated that cellular microdomains are important for many cellular processes, especially those involving Ca2+ signalling. Measurements of cytosolic Ca2+ report maximum concentrations of less than few micromolar, yet several cytosolic enzymes require concentrations of more than 20 μM Ca2+ to be activated. In this paper, we have resolved this apparent paradox by showing that the surface topology of cells represents an important and hitherto unrecognized feature for generating microdomains of high Ca2+ in cells. We show that whereas the standard modeling assumption of a smooth cell surface predicts only moderate localized effects, the more realistic “wrinkled” surface topology predicts that Ca2+ concentrations up to 80 μM can persist within the folds of membranes for significant times. This intra-wrinkle location may account for 5% of the total cell volume. Using different geometries of wrinkles, our simulations show that high Ca2+ microdomains will be generated most effectively by long narrow membrane wrinkles of similar dimensions to those found experimentally. This is a new concept which has not previously been considered, but which has ramifications as the intra-wrinkle location is also a strategic location at which Ca2+ acts as a regulator of the cortical cytoskeleton and plasma membrane expansion.
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Affiliation(s)
- Jens Christian Brasen
- CelCom, Institute of Biochemistry and Molecular Biology, University of Southern Denmark, Denmark.
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11
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Hallett MB, Dewitt S. Ironing out the wrinkles of neutrophil phagocytosis. Trends Cell Biol 2007; 17:209-14. [DOI: 10.1016/j.tcb.2007.03.002] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Revised: 02/06/2007] [Accepted: 03/02/2007] [Indexed: 11/29/2022]
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12
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Dewitt S, Hallett M. Leukocyte membrane "expansion": a central mechanism for leukocyte extravasation. J Leukoc Biol 2007; 81:1160-4. [PMID: 17360954 DOI: 10.1189/jlb.1106710] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The infiltration of inflamed tissues by leukocytes is a key event in the development and progression of inflammation. Although individual cytokines, which coordinate extravasation, have become the targets for therapy, a mechanism that is common to white cell extravasation, regardless of the specific molecular mechanism involved, would represent a more attractive therapeutic target. Such a target may be represented by the events underlying the spreading of leukocytes on the endothelium, which is a necessary prelude to extravasation. This leukocyte "spreading" involves an apparent increase in the cell surface area. The aim of this review is to examine whether the mechanism underlying the apparent expansion of plasma membrane surface area during leukocyte extravasation could be an "Achilles' heel," which is amenable to therapeutic intervention. In this short review, we evaluate the models proposed for the mechanism of membrane "expansion" and discuss recent data, which point to a mechanism of membrane "unwrinkling." The molecular pathway for the unwrinkling of the leukocyte plasma membrane may involve Ca2+ activation of mu-calpain and cleavage of cytoskeletal linkage molecules such as talin and ezrin. This route could be common to all extravasation signals and thus, represents a potential target for anti-inflammatory therapy.
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Affiliation(s)
- Sharon Dewitt
- Neutrophil Signalling Group, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
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13
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Hillson EJ, Dewitt S, Hallett MB. Optical methods for the measurement and manipulation of cytosolic free calcium in neutrophils. Methods Mol Biol 2007; 412:125-137. [PMID: 18453110 DOI: 10.1007/978-1-59745-467-4_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The measurement and manipulation of cytosolic free Ca2+ permits the investigation of the mechanisms of generation of the Ca2+ signal and cellular responses to these Ca2+ signals within living neutrophils. The optical methods most applicable to neutrophils, which will be discussed here, are (1) the use of fluorescent indicators of Ca2+ and (2) photoactivation of reagents involved in Ca2+ signaling. Both of these synthetic agents can be loaded into neutrophils as lipid-soluble esters or can be microinjected into the cell. In this chapter, we will outline some of the techniques that have been used to monitor, visualize, and manipulate Ca2+ in neutrophils.
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Affiliation(s)
- Esther J Hillson
- Neutrophil Signalling Group, School of Medicine, Cardiff University, Heath Park, United Kingdom
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14
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Han R, Grounds MD, Bakker AJ. Measurement of sub-membrane [Ca2+] in adult myofibers and cytosolic [Ca2+] in myotubes from normal and mdx mice using the Ca2+ indicator FFP-18. Cell Calcium 2006; 40:299-307. [PMID: 16765438 DOI: 10.1016/j.ceca.2006.04.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Revised: 04/04/2006] [Accepted: 04/12/2006] [Indexed: 10/24/2022]
Abstract
The hypothesis that intracellular Ca(2+) is elevated in dystrophic (mdx) skeletal muscle due to increased Ca(2+) influx is controversial. As the sub-sarcolemmal Ca(2+) ([Ca(2+)](mem)) should be even higher than the global cytosolic Ca(2+) in the presence of increased Ca(2+) influx, we investigated [Ca(2+)](mem) levels in collagenase-isolated adult flexor digitorum brevis (FDB) myofibres and myotubes of mdx and normal mice with the near-membrane Ca(2+) indicator FFP-18. Confocal imaging showed strong localization of FFP-18 to the sarcolemma only. No significant difference in [Ca(2+)](mem) was found in FDB myofibres of normal (77.3+/-3.8 nM, n=68) and mdx (79.3+/-5.6 nM, n=21, p=0.89) mice using FFP-18. Increasing external Ca(2+) to 18 mM did not significantly affect [Ca(2+)](mem) in either the normal or mdx myofibres. In the myotubes, the FFP-18 was non-selectively incorporated, distributing throughout the cytoplasm, and FFP-18-derived [Ca(2+)] values were similar to values obtained with Fura-2. Nevertheless, in the mdx myotubes, the [Ca(2+)] measured with FFP-18 increased linearly to a level approximately 2.75 times that of controls as the time of culture was prolonged. In older mdx myotubes (>or=8 days in culture), 18 mM extracellular Ca(2+) increased the steady state cytosolic [Ca(2+)] to approximately 22 times greater level than controls. This study suggests that the sub-sarcolemmal Ca(2+) homeostasis is well maintained in isolated adult mdx myofibers and also further supports the hypothesis that cytosolic Ca(2+) handling is compromised in mdx myotubes.
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Affiliation(s)
- Renzhi Han
- School of Biomedical and Chemical Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
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15
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Yip KHM, Zheng MH, Steer JH, Giardina TM, Han R, Lo SZ, Bakker AJ, Cassady AI, Joyce DA, Xu J. Thapsigargin modulates osteoclastogenesis through the regulation of RANKL-induced signaling pathways and reactive oxygen species production. J Bone Miner Res 2005; 20:1462-71. [PMID: 16007343 DOI: 10.1359/jbmr.050324] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2004] [Revised: 02/14/2005] [Accepted: 03/28/2005] [Indexed: 11/18/2022]
Abstract
UNLABELLED The mechanism by which TG modulates osteoclast formation and apoptosis is not clear. In this study, we showed a biphasic effect of TG on osteoclast formation and apoptosis through the regulation of ROS production, caspase-3 activity, cytosolic Ca2+, and RANKL-induced activation of NF-kappaB and AP-1 activities. INTRODUCTION Apoptosis and differentiation are among the consequences of changes in intracellular Ca2+ levels. In this study, we investigated the effects of the endoplasmic reticular Ca2+-ATPase inhibitor, thapsigargin (TG), on osteoclast apoptosis and differentiation. MATERIALS AND METHODS Both RAW264.7 cells and primary spleen cells were used to examine the effect of TG on RANKL-induced osteoclastogenesis. To determine the action of TG on signaling pathways, we used reporter gene assays for NF-kappaB and activator protein-1 (AP-1) activity, Western blotting for phospho-extracellular signal-related kinase (ERK), and fluorescent probes to measure changes in levels of intracellular calcium and reactive oxygen species (ROS). To assess rates of apoptosis, we measured changes in annexin staining, caspase-3 activity, and chromatin and F-actin microfilament structure. RESULTS At concentrations that caused a rapid rise in intracellular Ca2+, TG increased caspase-3 activity and promoted apoptosis in osteoclast-like cells (OLCs). Low concentrations of TG, which were insufficient to measurably alter intracellular Ca2+, unexpectedly suppressed caspase-3 activity and enhanced RANKL-induced osteoclastogenesis. At these lower concentrations, TG potentiated ROS production and RANKL-induced NF-kappaB activity, but suppressed RANKL-induced AP-1 activity and had little effect on ERK phosphorylation. CONCLUSION Our novel findings of a biphasic effect of TG are incompletely explained by our current understanding of TG action, but raise the possibility that low intensity or local changes in subcellular Ca2+ levels may regulate intracellular differentiation signaling. The extent of cross-talk between Ca2+ and RANKL-mediated intracellular signaling pathways might be important in determining whether cells undergo apoptosis or differentiate into OLCs.
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Affiliation(s)
- Kirk H M Yip
- Molecular Orthopaedic Laboratory, School of Surgery and Pathology, and Western Australian Institute for Medical Research, Nedlands, WA 6009, Australia
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16
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Golovina VA. Visualization of localized store-operated calcium entry in mouse astrocytes. Close proximity to the endoplasmic reticulum. J Physiol 2005; 564:737-49. [PMID: 15731184 PMCID: PMC1464454 DOI: 10.1113/jphysiol.2005.085035] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Unloading of endoplasmic reticulum (ER) Ca(2+) stores activates influx of extracellular Ca(2+) through 'store-operated' Ca(2+) channels (SOCs) in the plasma membrane (PM) of most cells, including astrocytes. A key unresolved issue concerning SOC function is their spatial relationship to ER Ca(2+) stores. Here, using high resolution imaging with the membrane-associated Ca(2+) indicator, FFP-18, it is shown that store-operated Ca(2+) entry (SOCE) in primary cultured mouse cortical astrocytes occurs at plasma membrane-ER junctions. In the absence of extracellular Ca(2+), depletion of ER Ca(2+) stores using cyclopiazonic acid, an ER Ca(2+)-ATPase inhibitor, and caffeine transiently increases the sub-plasma-membrane Ca(2+) concentration ([Ca(2+)](SPM)) within a restricted space between the plasma membrane and adjacent ER. Restoration of extracellular Ca(2+) causes localized Ca(2+) influx that first increases [Ca(2+)](SPM) in the same restricted regions and then, with a delay, in ER-free regions. Antisense knockdown of the TRPC1 gene, proposed to encode endogenous SOCs, markedly reduces SOCE measured with Fura-2. High resolution immunocytochemistry with anti-TRPC1 antibody reveals that these TRPC-encoded SOCs are confined to the PM microdomains adjacent to the underlying 'junctional' ER. Thus, Ca(2+) entry through TRPC-encoded SOCs is closely linked, not only functionally, but also structurally, to the ER Ca(2+) stores.
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Affiliation(s)
- Vera A Golovina
- Department of Physiology, University of Maryland School of Medicine, 685 W. Baltimore Street, Baltimore, MD 21201, USA.
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17
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Wang JP, Chen YS, Tsai CR, Huang LJ, Kuo SC. The blockade of cyclopiazonic acid-induced store-operated Ca2+ entry pathway by YC-1 in neutrophils. Biochem Pharmacol 2005; 68:2053-64. [PMID: 15476676 DOI: 10.1016/j.bcp.2004.07.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2004] [Accepted: 07/09/2004] [Indexed: 10/26/2022]
Abstract
In the presence of external Ca2+, pretreatment of neutrophils with 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1) inhibited the cyclopiazonic acid (CPA)-induced [Ca2+](i) elevation in a concentration- but not a time-dependent manner, while YC-1 had no effect on the Ca2+ signals in a Ca2+-free medium. YC-1 failed to inhibit ATP- and interleukin-8 (IL-8)-induced [Ca2+](i) changes. Addition of YC-1 after cell activation strongly inhibited the CPA-induced [Ca2+](i) changes. In a classical Ca2+ readdition protocol, a similar extent inhibition of Ca2+ spike by YC-1 introduced either prior to or after CPA stimulation was obtained. In rat neutrophils, mRNA for endothelial differentiation gene (edg)1, edg5, edg6 and edg8, the putative targets for sphingosine 1-phosphate (S1P), could be detected. However, S1P was found to have little effect on Ca(2+) signals. YC-1 did not inhibit but enhanced the sphingosine-induced [Ca2+](i) changes. Inhibition by YC-1 of CPA-induced [Ca2+](i) changes was not prevented by 7-nitroindazole and N-(3-aminomethyl)benzylacetamidine (1400W), two nitric oxide synthase (NOS) inhibitors, by aristolochic acid, a phospholipase A(2) inhibitor, or by suspension in a Na(+)-deprived medium. YC-1 did not affect the mitochondrial membrane potential. Moreover, YC-1 did not alter [Ca2+](i) changes in response to ionomycin after CPA and formyl-Met-Leu-Phe (fMLP) stimulation in a Ca2+-free medium. YC-1 had no effect on the basal [Ca2+](i) level, the pharmacologically isolated plasma membrane Ca2+-ATPase activity, and Ba2+ entry into CPA-activated cells. YC-1 alone resulted in the accumulation of actin filaments in neutrophils, while significantly reduced the intensity of actin filament staining in the subsequent activation with CPA. These results indicate that YC-1 inhibited CPA-activated store-operated Ca2+ entry (SOCE) probably through the direct blockade of channel activation and/or the disruption of the integrity of the actin cytoskeleton necessary for supporting Ca2+ entry pathway in neutrophils.
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Affiliation(s)
- Jih-Pyang Wang
- Department of Education and Research, Taichung Veterans General Hospital, Taichung 407, Taiwan, Republic of China.
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18
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Wang JP, Hsu MF, Ko HH, Lin CN. Stimulation of cellular free Ca2+ elevation and inhibition of store-operated Ca2+ entry by kazinol B in neutrophils. Naunyn Schmiedebergs Arch Pharmacol 2004; 370:500-9. [PMID: 15558242 DOI: 10.1007/s00210-004-0997-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2004] [Accepted: 10/11/2004] [Indexed: 10/26/2022]
Abstract
Kazinol B, a natural isoprenylated flavan, stimulated the [Ca(2+)](i) elevation in the presence or absence of Ca(2+) in the medium. Treatment with chymotrypsin or phorbol 12-myristate 13-acetate to shedding of L: -selectin had no effect on subsequent kazinol B-induced Ca(2+) response. Upon initial cyclopiazonic acid (CPA) treatment in the absence of external Ca(2+), the subsequent [Ca(2+)](i) rise followed by challenge with kazinol B was greatly diminished. The ryanodine receptor blockers, 8-bromo-cyclic ADP-ribose and ruthenium red did not affect kazinol B-evoked Ca(2+) release from internal stores. However, the inhibitors of sphingosine kinase, dimethylsphingosine, but not dihydrosphingosine, inhibited kazinol B-induced Ca(2+) release. Kazinol B-induced [Ca(2+)](i) rise was not affected by two nitric oxidase inhibitors, N-(3-aminomethyl)benzylacetamidine (1400W) and 7-nitroindazole, cytochalasin B and Na(+)-deprivation. This response was slightly attenuated by 2-aminoethyldiphenyl borate (2-APB), a D: -myo-inositol 1,4,5-trisphosphate (IP(3)) receptor blocker, and by genistein, a general tyrosine kinase inhibitor. However, the Ca(2+) response was greatly diminished by two actin filament reorganizers, calyculin A and jasplakinolide, 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY 294002), an inhibitor of phosphoinositide 3-kinase, N-(3-aminomethyl)benzylacetamidine (SB 203580), the p38 mitogen-activated protein kinase inhibitor, 1-[6-[17beta-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U-73122), the inhibitor of phospholipase C-coupled processes, and by 0.3 mM La(3+) or Ni(2+). Kazinol B did not evoke any appreciable Ba(2+) and Sr(2+) entry into cells. The Ca(2+) entry blockers, 1-[beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole (SKF-96365), but not cis-N-(2-phenylcyclopentyl)azacyclotridec-1-en-2-amine (MDL-12,330A), inhibited a kazinol B-induced [Ca(2+)](i) rise. Kazinol B had no effect on the pharmacologically isolated plasma membrane Ca(2+)-ATPase activity. In a Ca(2+)-free medium, kazinol B inhibited the subsequent Ca(2+) addition, resulting in robust entry in CPA- and formyl peptide-activated cells. Kazinol B produced a concentration-dependent reduction in the mitochondrial membrane potential. These results indicate that kazinol B stimulates Ca(2+) release from internal Ca(2+) store, probably through the sphingosine 1-phosphate and IP(3) signaling, and activates external Ca(2+) influx mainly through a non-store-operated Ca(2+) entry (non-SOCE) pathway. Inhibition of SOCE by kazinol B is probably attributable to a break in the Ca(2+) driven force of mitochondria.
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Affiliation(s)
- Jih-Pyang Wang
- Department of Education and Research, Taichung Veterans General Hospital, Taichung, Taiwan, Republic of China.
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Tian W, Laffafian I, Dewitt S, Hallett MB. Exclusion of exogenous phosphatidylinositol-3,4,5-trisphosphate from neutrophil-polarizing pseudopodia: stabilization of the uropod and cell polarity. EMBO Rep 2004; 4:982-8. [PMID: 14528267 PMCID: PMC1326405 DOI: 10.1038/sj.embor.embor947] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2002] [Revised: 06/11/2003] [Accepted: 08/21/2003] [Indexed: 12/17/2022] Open
Abstract
Although there is accumulating evidence that the generation and localization of phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P(3)) have important functions in neutrophil polarization and chemotaxis, the mechanism of this linkage has yet to be established. Here, using exogenous fluorescent PtdIns(3,4,5)P(3) introduced into the inner leaflet of the neutrophil plasma membrane by a cationic carrier, we show that: first, PtdIns(3,4,5)P(3) uniformly delivered to the neutrophil plasma membrane is excluded from newly forming pseudopodia; second, PtdIns(3,4,5)P(3) translocates to and is immobilized at the pole opposite a stable polarizing pseudopod; third, asymmetric delivery of PtdIns(3,4,5)P(3) to the neutrophil triggers the generation of polarizing pseudopodia at the opposite pole; and finally, PtdIns(3,4,5)P(3) triggers repetitive Ca(2+) signals, the onset of which precedes morphological polarization. These data suggest that translocation and immobilization of PtdIns(3,4,5)P(3) or a 3,x-phosphorylated metabolite in the uropod functions as an important polarization cue that defines neutrophil polarity and stabilizes the generation of pseudopodia at the opposite pole.
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Affiliation(s)
- Wei Tian
- Neutrophil Signalling Group, University
Department of Surgery, University of Wales College of Medicine, Heath
Park, Cardiff CF14 4XN, UK
| | - Iraj Laffafian
- Neutrophil Signalling Group, University
Department of Surgery, University of Wales College of Medicine, Heath
Park, Cardiff CF14 4XN, UK
| | - Sharon Dewitt
- Neutrophil Signalling Group, University
Department of Surgery, University of Wales College of Medicine, Heath
Park, Cardiff CF14 4XN, UK
| | - Maurice B. Hallett
- Neutrophil Signalling Group, University
Department of Surgery, University of Wales College of Medicine, Heath
Park, Cardiff CF14 4XN, UK
- Tel: +44 29 20 742748; Fax: +44 29 20 761623;
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20
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Olivero J, Ganey PE. Participation of Ca2+/calmodulin during activation of rat neutrophils by polychlorinated biphenyls. Biochem Pharmacol 2001; 62:1125-32. [PMID: 11597581 DOI: 10.1016/s0006-2952(01)00768-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The effects of Ca2+ and Ca2+/calmodulin on the polychlorinated biphenyl (PCB)-induced activation of phospholipase A2 (PLA2) in rat neutrophils were examined. The commercial PCB mixture Aroclor 1242 induced activation of PLA2 and promoted an increase in the intracellular free calcium concentration ([Ca2+]i). Bromoenol lactone (BEL), an inhibitor of the Ca2+-independent PLA2 isoform (iPLA2) activated by PCBs, did not abrogate the increase in [Ca2+]i, suggesting that this change in Ca2+ concentration is not downstream from the activation of iPLA2. TMB-8 [8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate], a blocker of the release of intracellular Ca2+, decreased Aroclor 1242-induced stimulation of PLA2 with a maximal inhibition of 17% at 50 microM. These two results suggest little direct dependence between the PCB-induced activation of iPLA2 and increase in [Ca2+]i. Calmidazolium and W7 [N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide], two chemically distinct calmodulin inhibitors, inhibited Aroclor 1242-induced PLA2 activity, whereas trifluoperazine (TFP), another inhibitor of calmodulin, had no effect at noncytotoxic concentrations. Thus, activation of PLA2 is dependent, in part, on calmodulin. Furthermore, both TFP and Aroclor 1242 inhibited neutrophil degranulation stimulated by the bacterial peptide formyl-methionyl-leucyl-phenylalanine. These results raise the possibility that some of the effects of PCBs on neutrophil function can be explained by effects on Ca2+/calmodulin-dependent processes.
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Affiliation(s)
- J Olivero
- Department of Pharmacology and Toxicology, National Food Safety and Toxicology Center and Institute for Environmental Toxicology, Michigan State University, East Lansing, MI 48824, USA
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Davies-Cox EV, Laffafian I, Hallett MB. Control of Ca2+ influx in human neutrophils by inositol 1,4,5-trisphosphate (IP3) binding: differential effects of micro-injected IP3 receptor antagonists. Biochem J 2001; 355:139-43. [PMID: 11256958 PMCID: PMC1221721 DOI: 10.1042/0264-6021:3550139] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Neutrophils signal Ca2+ changes in response to occupancy of G-protein-linked receptors such as the formylated peptide receptor. This Ca2+ signal is composed of two parts, inositol 1,4,5-trisphosphate (IP3)-triggered release of Ca2+ from an intracellular store and Ca2+ influx. In order to probe the relationship between these events, cytosolic free Ca2+ changes in neutrophils were monitored after micro-injection of agents which inhibit IP3 binding. Micro-injection of heparin into neutrophils totally inhibited both formylmethionyl-leucylphenylalanine-induced Ca2+ release and the subsequent Ca2+ influx. This effect was not due to prior depletion of Ca2+ stores. Furthermore, micro-injection with anti-IP3-receptor antibody also inhibited Ca2+ release. However, anti-IP3-receptor antibody and another high-molecular-mass IP3-binding antagonist, heparin-albumin conjugate, failed to inhibit the accompanying Ca2+ influx. It was concluded that two IP3-binding sites exist in neutrophils: one accessible by both heparin and the high-molecular-mass inhibitors of IP3 binding and responsible for Ca2+ release, and another inaccessible to high-molecular-mass molecules and responsible for Ca2+ influx.
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Affiliation(s)
- E V Davies-Cox
- Molecular Signalling Group, University Department of Surgery, University of Wales College of Medicine, Heath Park, Cardiff CF4 4XN, U.K
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22
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Braiman A, Gold'Shtein V, Priel Z. Feasibility of a sustained steep Ca(2+)Gradient in the cytosol of electrically non-excitable cells. J Theor Biol 2000; 206:115-30. [PMID: 10968942 DOI: 10.1006/jtbi.2000.2104] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In electrically non-excitable cells the predominant mode of calcium signaling is a biphasic rise in cytosolic calcium concentration. It results from Ca(2+)release from intracellular stores, followed by Ca(2+)influx across the plasma membrane. It has been hypothesized that prolonged calcium influx may result in a sustained local elevation of the cytosolic calcium concentration near the plasma membrane. The mathematical model presented here evaluates the cytosolic concentration of Ca(2+)as a function of time and distance from the plasma membrane. It consists of cytoplasmic calcium stores and a plasma membrane, both equipped with calcium channels and pumps, and an immobile cytoplasmic calcium buffer. The model has verified quantitatively the feasibility of a stable Ca(2+)gradient in the cytosol with high values of Ca(2+)concentration near the plasma membrane and evaluated its properties as a function of different cellular parameters. The formation of the gradient does not require special distribution of the intracellular contents, channels and pumps. However, it requires buffering of the cytosolic calcium by the intracellular stores and that the rate of calcium release from the stores near the plasma membrane be higher than in other parts of the cell. We suggest that this model can provide an adequate description of the elevated calcium plateau generally observed in electrically non-excitable cells.
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Affiliation(s)
- A Braiman
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel.
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23
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Fleischhacker E, Esenabhalu VE, Holzmann S, Skrabal F, Koidl B, Kostner GM, Graier WF. In human hypercholesterolemia increased reactivity of vascular smooth muscle cells is due to altered subcellular Ca(2+) distribution. Atherosclerosis 2000; 149:33-42. [PMID: 10704612 DOI: 10.1016/s0021-9150(99)00290-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
There is evidence that, besides an attenuated endothelium-dependent relaxation, functional changes in smooth muscle contractility occur in experimental hypercholesterolemic animals. Unfortunately, little is known of the situation in human arteries, and the intracellular mechanisms involved in the modulation of vascular smooth muscle function in human hypercholesterolemia are still unclear. Thus, besides acetylcholine-induced endothelium-dependent relaxation, smooth muscle reactivity to KCl, norepinephrine (NE) and phenylephrine (PE) was evaluated in uterine arteries from 34 control individuals (CI) and 22 hypercholesterolemic patients (HC). Contractions to KCl, norepinephrine and phenylephrine were enhanced by 1.3-, 2.1- and 3.5-fold in vessels from HC. Furthermore, the Ca(2+) signaling in the perinuclear cytosol, which promotes cell contraction, and that of the subplasmalemmal region, which contributes to smooth muscle relaxation, were examined in freshly isolated smooth muscle cells. In cells from HC, increases in perinuclear Ca(2+) concentration ([Ca(2+)](peri)) in response to 30 mM KCl and 300 nM NE were increased by 67 and 93%, respectively. In contrast, the increase in the subplasmalemmal Ca(2+) concentration ([Ca(2+)](sub)) to 10 microM NE was reduced in cells from HC by 33%. No further differences in perinuclear and subplasmalemmal Ca(2+) signaling were found in cultured smooth muscle cells from CI and HC (primary culture 4-6 weeks after isolation). These data indicate a significant change in the subcellular Ca(2+) distribution in smooth muscle cells from HC. In addition, production of superoxide anions (O(2)(-)) was increased 3.8-fold in uterine arteries from HC. Treatment of smooth muscle cells with the O(2)(-)-generating mixture xanthine oxidase/hypoxanthine mimicked hypercholesterolemia on smooth muscle Ca(2+) signaling. From these findings, we conclude that during hypercholesterolemia, besides a reduced endothelium-dependent relaxation, changes in smooth muscle reactivity take place. Thereby, smooth muscle contractility is increased possibly due to the observed changes in subcellular Ca(2+) signaling. The observed increased O(2)(-) production in HC might play a crucial role in the alteration of smooth muscle function in hypercholesterolemia.
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MESH Headings
- Aged
- Biological Transport, Active/physiology
- Calcium Signaling/physiology
- Calcium-Transporting ATPases/metabolism
- Cells, Cultured
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiology
- Female
- Humans
- Hypercholesterolemia/complications
- Middle Aged
- Muscle Contraction/drug effects
- Muscle Contraction/physiology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiopathology
- Norepinephrine/pharmacology
- Phenylephrine/pharmacology
- Potassium Chloride/pharmacology
- Reference Values
- Sensitivity and Specificity
- Uterus/blood supply
- Vasoconstrictor Agents/pharmacology
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Affiliation(s)
- E Fleischhacker
- Department of Medical Biochemistry, Karl-Franzens University of Graz, Harrachgasse 21/III, A-8010, Graz, Austria
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24
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Hallett MB, Hodges R, Cadman M, Blanchfield H, Dewitt S, Pettit EJ, Laffafian I, Davies EV. Techniques for measuring and manipulating free Ca2+ in the cytosol and organelles of neutrophils. J Immunol Methods 1999; 232:77-88. [PMID: 10618511 DOI: 10.1016/s0022-1759(99)00167-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ca(2+) signalling in neutrophils is important for triggering and coordinating the behaviour of neutrophils. Fluorescent probes for cytosolic free Ca(2+) concentration, e.g., fura2 and fluo3, have been widely used in neutrophils. These probes can be used to monitor Ca(2+) in the cytosol, the nucleus, near the plasma membrane and theoretically within Ca(2+) storage organelles. The longer wavelength indicators, e.g., fluo3 and calcium green, can be used confocally to monitor subcellular Ca(2+) changes in the cytosol of neutrophils and in the nucleus. Confocal techniques also permit "impossible views" imaging of Ca(2+) and newer scanning techniques promise very fast temporal resolution. Techniques using chlortetracycline (CTC) and DiOC(6)(3) are also described for monitoring the position of Ca(2+) storage sites in neutrophils and for manipulating their activity. Thus, in this review, a spectrum of new (and older) optical techniques are presented which are useful for measuring, monitoring and manipulating cytosolic free Ca(2+) concentration and Ca(2+) storage in neutrophils. With these techniques, it is hoped that more insight will be gained into both the mechanism of and the consequences of Ca(2+) signalling in neutrophils.
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Affiliation(s)
- M B Hallett
- Molecular Signalling Group, University Department of Surgery, University of Wales College of Medicine, Heath Park, Cardiff, UK.
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25
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Abstract
To a certain extent, all cellular, physiological, and pathological phenomena that occur in cells are accompanied by ionic changes. The development of techniques allowing the measurement of such ion activities has contributed substantially to our understanding of normal and abnormal cellular function. Digital video microscopy, confocal laser scanning microscopy, and more recently multiphoton microscopy have allowed the precise spatial analysis of intracellular ion activity at the subcellular level in addition to measurement of its concentration. It is well known that Ca2+ regulates numerous physiological cellular phenomena as a second messenger as well as triggering pathological events such as cell injury and death. A number of methods have been developed to measure intracellular Ca2+. In this review, we summarize the advantages and pitfalls of a variety of Ca2+ indicators used in both optical and nonoptical techniques employed for measuring intracellular Ca2+ concentration.
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Affiliation(s)
- A Takahashi
- Department of Cellular and Structural Biology, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900, USA
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26
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Bruton JD, Katz A, Westerblad H. Insulin increases near-membrane but not global Ca2+ in isolated skeletal muscle. Proc Natl Acad Sci U S A 1999; 96:3281-6. [PMID: 10077675 PMCID: PMC15933 DOI: 10.1073/pnas.96.6.3281] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has long been debated whether changes in Ca2+ are involved in insulin-stimulated glucose uptake in skeletal muscle. We have now investigated the effect of insulin on the global free myoplasmic Ca2+ concentration and the near-membrane free Ca2+ concentration ([Ca2+]mem) in intact, single skeletal muscle fibers from mice by using fluorescent Ca2+ indicators. Insulin has no effect on the global free myoplasmic Ca2+ concentration. However, insulin increases [Ca2+]mem by approximately 70% and the half-maximal increase in [Ca2+]mem occurs at an insulin concentration of 110 microunits per ml. The increase in [Ca2+]mem by insulin persists when sarcoplasmic reticulum Ca2+ release is inhibited but is lost by perfusing the fiber with a low Ca2+ medium or by addition of L-type Ca2+ channel inhibitors. Thus, insulin appears to stimulate Ca2+ entry into muscle cells via L-type Ca2+ channels. Wortmannin, which inhibits insulin-mediated activation of glucose transport in isolated skeletal muscle, also inhibits the insulin-mediated increase in [Ca2+]mem. These data demonstrate a new facet of insulin signaling and indicate that insulin-mediated increases in [Ca2+]mem in skeletal muscle may underlie important actions of the hormone.
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Affiliation(s)
- J D Bruton
- Department of Physiology and Pharmacology, Karolinska Institute, 171 77 Stockholm, Sweden
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27
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Paltauf-Doburzynska J, Posch K, Paltauf G, Graier WF. Stealth ryanodine-sensitive Ca2+ release contributes to activity of capacitative Ca2+ entry and nitric oxide synthase in bovine endothelial cells. J Physiol 1998; 513 ( Pt 2):369-79. [PMID: 9806989 PMCID: PMC2231284 DOI: 10.1111/j.1469-7793.1998.369bb.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
1. The involvement of ryanodine-sensitive Ca2+ release (RsCR) in bradykinin (Bk)-induced Ca2+ release, capacitative Ca2+ entry (CCE) and nitric oxide synthase (NOS) activation was assessed in freshly isolated bovine coronary artery endothelial cells. 2. Using deconvolution microscopy fura-2 was found throughout the whole cytosol, while the cell membrane impermeable dye FFP-18 was exclusively in the cell membrane. Thus, perinuclear ([Ca2+]pn) and subplasmalemmal Ca2+ concentration ([Ca2+]sp) were monitored using fura-2 and FFP-18. 3. Inhibition of Na+-Ca2+ exchange by lowering extracellular Na+ concentration augmented the Bk-induced [Ca2+]pn signal in Ca2+-free solution. This effect was abolished when RsCR was prevented with 25 micromol l-1 ryanodine, while inhibition of RsCR had no effect on Bk-induced increase in [Ca2+]pn without inhibition of Na+-Ca2+ exchange. 4. Initiating RsCR by 200 nmol l-1 ryanodine increased [Ca2+]sp, while [Ca2+]pn remained constant. However, when Na+-Ca2+ exchange was prevented, ryanodine was also able to elevate [Ca2+]pn. 5. Blockage of RsCR diminished Ca2+ extrusion in response to stimulation with Bk in normal Na+-containing solution. 6. Inhibition of RsCR blunted Bk-activated CCE, while inhibition of Na+-Ca2+ exchange during stimulation enhanced CCE. 7. Although direct activation of RsCR failed to activate NOS, inhibition of RsCR diminished the effect of ATP and Bk on NOS, while the effect of thapsigargin remained unchanged. 8. These data suggest that during stimulation subplasmalemmal RsCR occurs, which contributes to the activities of CCE and NOS. Thus, the function of the subplasmalemmal Ca2+ control unit must be extended as a regulator for CCE and NOS.
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Affiliation(s)
- J Paltauf-Doburzynska
- Department of Medical Biochemistry, University of Graz, Harrachgasse 21/III, A-8010 Graz, Austria
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28
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Davies EV, Hallett MB. High micromolar Ca2+ beneath the plasma membrane in stimulated neutrophils. Biochem Biophys Res Commun 1998; 248:679-83. [PMID: 9703986 DOI: 10.1006/bbrc.1998.9031] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ca2+ near the inner face of the plasma membrane, as reported by the membrane associated fluorescent Ca2+ probe FFP-18, was higher than the bulk cytosolic free Ca2+ concentration both in resting neutrophils and in response to f-met-leu-phe. Influx caused Ca2+ close to the plasma membrane to rise more rapidly than the bulk cytosolic free Ca2+ and to reach a peak concentration of at least 30 microM. This zone of high Ca2+ was localised to just beneath the plasma membrane and did not extend more than 0.1 micron into the cell, as it was undetected by the bulk cytosolic free Ca2+ probes magfura2 and fura2. From these data, reconstruction of the distribution of Ca2+ within the neutrophil showed that the high Ca2+ signal at the cell cortex rapidly subsided to give a uniform free Ca2+ across the cell.
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Affiliation(s)
- E V Davies
- University Department of Surgery, University of Wales College of Medicine, Heath Park, Cardiff, United Kingdom
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29
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Davies EV, Roberts GM, Hallett MB. Spatial and temporal separation of calcium signals in myeloid cells stimulated by immune complexes. Cell Signal 1997; 9:457-62. [PMID: 9376228 DOI: 10.1016/s0898-6568(97)00039-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Stimulation of large (100 microns) human myeloid cells with immune complexes resulted in Ca2+ spiking. Both global and regional changes in the intracellular cytosolic free Ca2+ concentration were detected in response to immune complex stimulation. The regional changes were mediated by release of Ca2+ from stores, whereas global changes were mediated by Ca2+ influx. They occurred independently of each other, with release of Ca2+ from intracellular Ca2+ stores being separated from transmembrane influx of Ca2+. Bromophenacyl bromide, an 1-plastin binding agent, inhibited store release without preventing transmembrane influx of Ca2+. The large size of the myeloid cells used here allowed the visualisation of the spatial and temporal separation of store release from transmembrane influx of Ca2+, providing further evidence for the existence of independent Ca2+ store release and Ca2+ influx mechanisms in these cells.
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Affiliation(s)
- E V Davies
- Department of Surgery, University of Wales College of Medicine, Heath Park, Cardiff, U.K
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