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Zhou W, Hsu AY, Wang Y, Syahirah R, Wang T, Jeffries J, Wang X, Mohammad H, Seleem MN, Umulis D, Deng Q. Mitofusin 2 regulates neutrophil adhesive migration and the actin cytoskeleton. J Cell Sci 2020; 133:jcs248880. [PMID: 32788232 PMCID: PMC7491649 DOI: 10.1242/jcs.248880] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/29/2020] [Indexed: 12/11/2022] Open
Abstract
Neutrophils rely on glycolysis for energy production. How mitochondria regulate neutrophil function is not fully understood. Here, we report that mitochondrial outer membrane protein Mitofusin 2 (MFN2) regulates neutrophil homeostasis and chemotaxis in vivoMfn2-deficient neutrophils are released from the hematopoietic tissue, trapped in the vasculature in zebrafish embryos, and not capable of chemotaxis. Consistent with this, human neutrophil-like cells that are deficient for MFN2 fail to arrest on activated endothelium under sheer stress or perform chemotaxis on 2D surfaces. Deletion of MFN2 results in a significant reduction of neutrophil infiltration to the inflamed peritoneal cavity in mice. Mechanistically, MFN2-deficient neutrophil-like cells display disrupted mitochondria-ER interaction, heightened intracellular Ca2+ levels and elevated Rac activation after chemokine stimulation. Restoring a mitochondria-ER tether rescues the abnormal Ca2+ levels, Rac hyperactivation and chemotaxis defect resulting from MFN2 depletion. Finally, inhibition of Rac activation restores chemotaxis in MFN2-deficient neutrophils. Taken together, we have identified that MFN2 regulates neutrophil migration via maintaining the mitochondria-ER interaction to suppress Rac activation, and uncovered a previously unrecognized role of MFN2 in regulating cell migration and the actin cytoskeleton.This article has an associated First Person interview with the first authors of the paper.
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Affiliation(s)
- Wenqing Zhou
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Alan Y Hsu
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Yueyang Wang
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Ramizah Syahirah
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Tianqi Wang
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Jacob Jeffries
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Xu Wang
- Department of Agricultural & Biological Engineering, Purdue University, West Lafayette, IN 47907, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Haroon Mohammad
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
| | - Mohamed N Seleem
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
- Purdue Institute for Inflammation, Immunology & Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
| | - David Umulis
- Department of Agricultural & Biological Engineering, Purdue University, West Lafayette, IN 47907, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Qing Deng
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
- Purdue Institute for Inflammation, Immunology & Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
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2
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Lopez-Guerrero AM, Espinosa-Bermejo N, Sanchez-Lopez I, Macartney T, Pascual-Caro C, Orantos-Aguilera Y, Rodriguez-Ruiz L, Perez-Oliva AB, Mulero V, Pozo-Guisado E, Martin-Romero FJ. RAC1-Dependent ORAI1 Translocation to the Leading Edge Supports Lamellipodia Formation and Directional Persistence. Sci Rep 2020; 10:6580. [PMID: 32313105 PMCID: PMC7171199 DOI: 10.1038/s41598-020-63353-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 03/26/2020] [Indexed: 12/18/2022] Open
Abstract
Tumor invasion requires efficient cell migration, which is achieved by the generation of persistent and polarized lamellipodia. The generation of lamellipodia is supported by actin dynamics at the leading edge where a complex of proteins known as the WAVE regulatory complex (WRC) promotes the required assembly of actin filaments to push the front of the cell ahead. By using an U2OS osteosarcoma cell line with high metastatic potential, proven by a xenotransplant in zebrafish larvae, we have studied the role of the plasma membrane Ca2+ channel ORAI1 in this process. We have found that epidermal growth factor (EGF) triggered an enrichment of ORAI1 at the leading edge, where colocalized with cortactin (CTTN) and other members of the WRC, such as CYFIP1 and ARP2/3. ORAI1-CTTN co-precipitation was sensitive to the inhibition of the small GTPase RAC1, an upstream activator of the WRC. RAC1 potentiated ORAI1 translocation to the leading edge, increasing the availability of surface ORAI1 and increasing the plasma membrane ruffling. The role of ORAI1 at the leading edge was studied in genetically engineered U2OS cells lacking ORAI1 expression that helped us to prove the key role of this Ca2+ channel on lamellipodia formation, lamellipodial persistence, and cell directness, which are required for tumor cell invasiveness in vivo.
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Affiliation(s)
- Aida M Lopez-Guerrero
- Department of Biochemistry and Molecular Biology, School of Life Sciences and Institute of Molecular Pathology Biomarkers, University of Extremadura, Badajoz, 06006, Spain
| | - Noelia Espinosa-Bermejo
- Department of Biochemistry and Molecular Biology, School of Life Sciences and Institute of Molecular Pathology Biomarkers, University of Extremadura, Badajoz, 06006, Spain
| | - Irene Sanchez-Lopez
- Department of Biochemistry and Molecular Biology, School of Life Sciences and Institute of Molecular Pathology Biomarkers, University of Extremadura, Badajoz, 06006, Spain
| | - Thomas Macartney
- MRC- Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, United Kingdom
| | - Carlos Pascual-Caro
- Department of Biochemistry and Molecular Biology, School of Life Sciences and Institute of Molecular Pathology Biomarkers, University of Extremadura, Badajoz, 06006, Spain
| | - Yolanda Orantos-Aguilera
- Department of Biochemistry and Molecular Biology, School of Life Sciences and Institute of Molecular Pathology Biomarkers, University of Extremadura, Badajoz, 06006, Spain
| | - Lola Rodriguez-Ruiz
- Department of Cell Biology and Histology, University of Murcia, IMIB-Arrixaca, Murcia, 30100, Spain
| | - Ana B Perez-Oliva
- Department of Cell Biology and Histology, University of Murcia, IMIB-Arrixaca, Murcia, 30100, Spain
| | - Victoriano Mulero
- Department of Cell Biology and Histology, University of Murcia, IMIB-Arrixaca, Murcia, 30100, Spain
| | - Eulalia Pozo-Guisado
- Department of Cell Biology, School of Medicine and Institute of Molecular Pathology Biomarkers, University of Extremadura, Badajoz, 06006, Spain.
| | - Francisco Javier Martin-Romero
- Department of Biochemistry and Molecular Biology, School of Life Sciences and Institute of Molecular Pathology Biomarkers, University of Extremadura, Badajoz, 06006, Spain.
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3
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Ishak R, Hallett MB. Defective rapid cell shape and transendothelial migration by calpain-1 null neutrophils. Biochem Biophys Res Commun 2018; 506:1065-1070. [DOI: 10.1016/j.bbrc.2018.10.174] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 10/28/2018] [Indexed: 12/26/2022]
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4
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Paudel S, Sindelar R, Saha M. Calcium Signaling in Vertebrate Development and Its Role in Disease. Int J Mol Sci 2018; 19:E3390. [PMID: 30380695 PMCID: PMC6274931 DOI: 10.3390/ijms19113390] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 10/18/2018] [Accepted: 10/22/2018] [Indexed: 12/11/2022] Open
Abstract
Accumulating evidence over the past three decades suggests that altered calcium signaling during development may be a major driving force for adult pathophysiological events. Well over a hundred human genes encode proteins that are specifically dedicated to calcium homeostasis and calcium signaling, and the majority of these are expressed during embryonic development. Recent advances in molecular techniques have identified impaired calcium signaling during development due to either mutations or dysregulation of these proteins. This impaired signaling has been implicated in various human diseases ranging from cardiac malformations to epilepsy. Although the molecular basis of these and other diseases have been well studied in adult systems, the potential developmental origins of such diseases are less well characterized. In this review, we will discuss the recent evidence that examines different patterns of calcium activity during early development, as well as potential medical conditions associated with its dysregulation. Studies performed using various model organisms, including zebrafish, Xenopus, and mouse, have underscored the critical role of calcium activity in infertility, abortive pregnancy, developmental defects, and a range of diseases which manifest later in life. Understanding the underlying mechanisms by which calcium regulates these diverse developmental processes remains a challenge; however, this knowledge will potentially enable calcium signaling to be used as a therapeutic target in regenerative and personalized medicine.
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Affiliation(s)
- Sudip Paudel
- College of William and Mary, Williamsburg, VA 23187, USA.
| | - Regan Sindelar
- College of William and Mary, Williamsburg, VA 23187, USA.
| | - Margaret Saha
- College of William and Mary, Williamsburg, VA 23187, USA.
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5
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Francis EA, Heinrich V. Extension of chemotactic pseudopods by nonadherent human neutrophils does not require or cause calcium bursts. Sci Signal 2018. [PMID: 29535263 DOI: 10.1126/scisignal.aal4289] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Global bursts in free intracellular calcium (Ca2+) are among the most conspicuous signaling events in immune cells. To test the common view that Ca2+ bursts mediate rearrangement of the actin cytoskeleton in response to the activation of G protein-coupled receptors, we combined single-cell manipulation with fluorescence imaging and monitored the Ca2+ concentration in individual human neutrophils during complement-mediated chemotaxis. By decoupling purely chemotactic pseudopod formation from cell-substrate adhesion, we showed that physiological concentrations of anaphylatoxins, such as C5a, induced nonadherent human neutrophils to form chemotactic pseudopods but did not elicit Ca2+ bursts. By contrast, pathological or supraphysiological concentrations of C5a often triggered Ca2+ bursts, but pseudopod protrusion stalled or reversed in such cases, effectively halting chemotaxis, similar to sepsis-associated neutrophil paralysis. The maximum increase in cell surface area during pseudopod extension in pure chemotaxis was much smaller-by a factor of 8-than the known capacity of adherent human neutrophils to expand their surface. Because the measured rise in cortical tension was not sufficient to account for this difference, we attribute the limited deformability to a reduced ability of the cytoskeleton to generate protrusive force in the absence of cell adhesion. Thus, we hypothesize that Ca2+ bursts in neutrophils control a mechanistic switch between two distinct modes of cytoskeletal organization and dynamics. A key element of this switch appears to be the expedient coordination of adhesion-dependent lock or release events of cytoskeletal membrane anchors.
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Affiliation(s)
- Emmet A Francis
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, USA
| | - Volkmar Heinrich
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, USA.
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6
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Liu X, Wang T, Wang Y, Chen Z, Hua D, Yao X, Ma X, Zhang P. Orai1 is critical for Notch-driven aggressiveness under hypoxic conditions in triple-negative breast cancers. Biochim Biophys Acta Mol Basis Dis 2018; 1864:975-986. [PMID: 29307746 DOI: 10.1016/j.bbadis.2018.01.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 12/20/2017] [Accepted: 01/02/2018] [Indexed: 12/29/2022]
Abstract
It is believed that hypoxia stimulates triple-negative breast cancers (TNBCs) metastasis, which is associated with a poor prognosis. However, the underlying mechanism remains unclear. Here, we demonstrated that hypoxia up-regulates both the levels of Orai1 and Notch1, and the increase in Orai1 is mediated by Notch1 signaling in TNBCs. Functionally, Orai1 caused a sustained elevation of intracellular Ca2+ via Store-operated Ca2+ entry (SOCE), then activated the calcineurin-nuclear factor of activated T-cell 4 (NFAT4, also named NFATc3) in hypoxic TNBCs. Furthermore, pharmacologic inhibition or gene-silencing studies showed that the aggressiveness mediated by Orai1 during hypoxia is dependent on the Notch1/Orai1/SOCE/NFAT4 signaling. Moreover, Orai1 signaling also mediated hypoxia-induced angiogenesis in TNBCs. Thus, our results revealed a novel role of Orai1 as an inducer of aggression and angiogenesis under hypoxic conditions, and this suggests a novel mechanism of hypoxia-induced invasion. It may be worthwhile to further explore the potential of using Orai1 signaling as new target for anti-tumor therapy in TNBCs.
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Affiliation(s)
- Xiaoyu Liu
- School of Medicine, Jiangnan University, Wuxi, China; School of Biomedical Sciences, the Chinese University of Hong Kong, Hong Kong, China
| | - Teng Wang
- Department of Oncology, Affiliated Hospital of Jiangnan University, Wuxi, China
| | - Yan Wang
- Key Laboratory of Cardiovascular Medicine and Clinical Pharmacology of Shanxi Province, Taiyuan, China
| | - Zhen Chen
- School of Medicine, Jiangnan University, Wuxi, China
| | - Dong Hua
- Department of Oncology, Affiliated Hospital of Jiangnan University, Wuxi, China
| | - Xiaoqiang Yao
- School of Biomedical Sciences, the Chinese University of Hong Kong, Hong Kong, China
| | - Xin Ma
- School of Medicine, Jiangnan University, Wuxi, China.
| | - Peng Zhang
- School of Medicine, Jiangnan University, Wuxi, China.
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7
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Weddell JC, Chen S, Imoukhuede PI. VEGFR1 promotes cell migration and proliferation through PLCγ and PI3K pathways. NPJ Syst Biol Appl 2017; 4:1. [PMID: 29263797 PMCID: PMC5736688 DOI: 10.1038/s41540-017-0037-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 11/08/2017] [Accepted: 11/21/2017] [Indexed: 12/16/2022] Open
Abstract
The ability to control vascular endothelial growth factor (VEGF) signaling offers promising therapeutic potential for vascular diseases and cancer. Despite this promise, VEGF-targeted therapies are not clinically effective for many pathologies, such as breast cancer. VEGFR1 has recently emerged as a predictive biomarker for anti-VEGF efficacy, implying a functional VEGFR1 role beyond its classically defined decoy receptor status. Here we introduce a computational approach that accurately predicts cellular responses elicited via VEGFR1 signaling. Aligned with our model prediction, we show empirically that VEGFR1 promotes macrophage migration through PLCγ and PI3K pathways and promotes macrophage proliferation through a PLCγ pathway. These results provide new insight into the basic function of VEGFR1 signaling while offering a computational platform to quantify signaling of any receptor.
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Affiliation(s)
- Jared C. Weddell
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Si Chen
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - P. I. Imoukhuede
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
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8
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Topographical interrogation of the living cell surface reveals its role in rapid cell shape changes during phagocytosis and spreading. Sci Rep 2017; 7:9790. [PMID: 28851970 PMCID: PMC5575107 DOI: 10.1038/s41598-017-09761-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 07/28/2017] [Indexed: 11/16/2022] Open
Abstract
Dramatic and rapid changes in cell shape are perhaps best exemplified by phagocytes, such as neutrophils. These cells complete the processes of spreading onto surfaces, and phagocytosis within 100 s of stimulation. Although these cell shape changes are accompanied by an apparent large increase in cell surface area, the nature of the membrane “reservoir” for the additional area is unclear. One proposal is that the wrinkled cell surface topography (which forms micro-ridges on the neutrophil surface) provides the resource for neutrophils to expand their available surface area. However, it has been problematic to test this proposal in living cells because these surface structures are sub-light microscopic. In this paper, we report the development of a novel approach, a variant of FRAP (fluorescent recovery after photo-bleaching) modified to interrogate the diffusion path-lengths of membrane associated molecules. This approach provides clear evidence that the cell surface topography changes dramatically during neutrophil shape change (both locally and globally) and can be triggered by elevating cytosolic Ca2+.
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9
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Mishra S, Tripathi R, Singh S. Crosstalk of proteins, miRNAs involved in metastatic and epithelial–mesenchymal transition pathways. FRONTIERS IN LIFE SCIENCE 2016. [DOI: 10.1080/21553769.2016.1256843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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10
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Antunes Dos Santos A, Appel Hort M, Culbreth M, López-Granero C, Farina M, Rocha JBT, Aschner M. Methylmercury and brain development: A review of recent literature. J Trace Elem Med Biol 2016; 38:99-107. [PMID: 26987277 PMCID: PMC5011031 DOI: 10.1016/j.jtemb.2016.03.001] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 03/02/2016] [Indexed: 02/02/2023]
Abstract
Methylmercury (MeHg) is a potent environmental pollutant, which elicits significant toxicity in humans. The central nervous system (CNS) is the primary target of toxicity, and is particularly vulnerable during development. Maternal exposure to MeHg via consumption of fish and seafood can have irreversible effects on the neurobehavioral development of children, even in the absence of symptoms in the mother. It is well documented that developmental MeHg exposure may lead to neurological alterations, including cognitive and motor dysfunction. The neurotoxic effects of MeHg on the developing brain have been extensively studied. The mechanism of toxicity, however, is not fully understood. No single process can explain the multitude of effects observed in MeHg-induced neurotoxicity. This review summarizes the most current knowledge on the effects of MeHg during nervous system development considering both, in vitro and in vivo experimental models. Considerable attention was directed towards the role of glutamate and calcium dyshomeostasis, mitochondrial dysfunction, as well as the effects of MeHg on cytoskeletal components/regulators.
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Affiliation(s)
| | - Mariana Appel Hort
- Institute of Biological Sciences, Federal University of Rio Grande, Campus Carreiros, Rio Grande do Sul, Brazil
| | - Megan Culbreth
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Caridad López-Granero
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Marcelo Farina
- Department of Biochemistry, Federal University of Santa Catarina, Florianopolis, Santa Catarina, Brazil
| | - Joao B T Rocha
- Department of Biochemistry, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA.
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11
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Ribeiro MPC, Custódio JBA, Santos AE. Ionotropic glutamate receptor antagonists and cancer therapy: time to think out of the box? Cancer Chemother Pharmacol 2016; 79:219-225. [PMID: 27586965 DOI: 10.1007/s00280-016-3129-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 08/04/2016] [Indexed: 12/26/2022]
Abstract
Glutamate has a trophic function in the development of the central nervous system, regulating the proliferation and migration of neuronal progenitors. The resemblance between neuronal embryonic and tumor cells has paved the way for the investigation of the effects of glutamate on tumor cells. Indeed, tumor cells derived from neuronal tissue express ionotropic glutamate receptor (iGluRs) subunits and iGluR antagonists decrease cell proliferation. Likewise, iGluRs subunits are expressed in several peripheral cancer cells and blockade of the N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) ionotropic glutamate receptor subtypes decreases their proliferation and migration. Although these mechanisms are still being investigated, the inhibition of the mitogen-activated protein kinase pathway was shown to play a key role in the antiproliferative activity of iGluR antagonists. Importantly, MK-801, a NMDAR channel blocker, was effective and well tolerated in animal models of melanoma, lung, and breast cancers, suggesting that the blockade of iGluR signaling may represent a new strategy for cancer treatment. In this review, we focus on the significance of NMDA and AMPA receptor expression in tumor cells, as well as possible therapeutic strategies targeting these receptors.
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Affiliation(s)
- Mariana P C Ribeiro
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354, Coimbra, Portugal.,Laboratory of Biochemistry, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal
| | - José B A Custódio
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354, Coimbra, Portugal.,Laboratory of Biochemistry, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal
| | - Armanda E Santos
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354, Coimbra, Portugal. .,Laboratory of Biochemistry, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal.
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12
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Diz-Muñoz A, Thurley K, Chintamen S, Altschuler SJ, Wu LF, Fletcher DA, Weiner OD. Membrane Tension Acts Through PLD2 and mTORC2 to Limit Actin Network Assembly During Neutrophil Migration. PLoS Biol 2016; 14:e1002474. [PMID: 27280401 PMCID: PMC4900667 DOI: 10.1371/journal.pbio.1002474] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 05/04/2016] [Indexed: 11/18/2022] Open
Abstract
For efficient polarity and migration, cells need to regulate the magnitude and spatial distribution of actin assembly. This process is coordinated by reciprocal interactions between the actin cytoskeleton and mechanical forces. Actin polymerization-based protrusion increases tension in the plasma membrane, which in turn acts as a long-range inhibitor of actin assembly. These interactions form a negative feedback circuit that limits the magnitude of membrane tension in neutrophils and prevents expansion of the existing front and the formation of secondary fronts. It has been suggested that the plasma membrane directly inhibits actin assembly by serving as a physical barrier that opposes protrusion. Here we show that efficient control of actin polymerization-based protrusion requires an additional mechanosensory feedback cascade that indirectly links membrane tension with actin assembly. Specifically, elevated membrane tension acts through phospholipase D2 (PLD2) and the mammalian target of rapamycin complex 2 (mTORC2) to limit actin nucleation. In the absence of this pathway, neutrophils exhibit larger leading edges, higher membrane tension, and profoundly defective chemotaxis. Mathematical modeling suggests roles for both the direct (mechanical) and indirect (biochemical via PLD2 and mTORC2) feedback loops in organizing cell polarity and motility—the indirect loop is better suited to enable competition between fronts, whereas the direct loop helps spatially organize actin nucleation for efficient leading edge formation and cell movement. This circuit is essential for polarity, motility, and the control of membrane tension. A mechanosensory biochemical cascade involving phospholipase D2 and mTORC2 coordinates physical forces and cytoskeletal rearrangements to allow efficient polarization and migration of neutrophils. How cells regulate the size and number of their protrusions for efficient polarity and motility is a fundamental question in cell biology. We recently found that immune cells known as neutrophils use physical forces to regulate this process. Actin polymerization-based protrusion stretches the plasma membrane, and this increased membrane tension acts as a long-range inhibitor of actin-based protrusions elsewhere in the cell. Here we investigate how membrane tension limits protrusion. We demonstrate that the magnitude of actin network assembly in neutrophils is determined by a mechanosensory biochemical cascade that converts increases in membrane tension into decreases in protrusion. Specifically, we show that increasing plasma membrane tension acts through a pathway containing the phospholipase D2 (PLD2) and the mammalian target of rapamycin complex 2 (mTORC2) to limit actin network assembly. Without this negative feedback pathway, neutrophils exhibit larger leading edges, higher membrane tension, and profoundly defective chemotaxis. Mathematical modeling indicates that this feedback circuit is a favorable topology to enable competition between protrusions during neutrophil polarization. Our work shows how biochemical signals, physical forces, and the cytoskeleton can collaborate to generate large-scale cellular organization.
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Affiliation(s)
- Alba Diz-Muñoz
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
- Bioengineering Department and Biophysics Program, University of California Berkeley, Berkeley, California, United States of America
| | - Kevin Thurley
- Dept. of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Sana Chintamen
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
| | - Steven J. Altschuler
- Dept. of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Lani F. Wu
- Dept. of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Daniel A. Fletcher
- Bioengineering Department and Biophysics Program, University of California Berkeley, Berkeley, California, United States of America
- * E-mail: (DAF); (ODW)
| | - Orion D. Weiner
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
- * E-mail: (DAF); (ODW)
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13
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Direct In Vivo Manipulation and Imaging of Calcium Transients in Neutrophils Identify a Critical Role for Leading-Edge Calcium Flux. Cell Rep 2015; 13:2107-17. [PMID: 26673320 DOI: 10.1016/j.celrep.2015.11.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 09/21/2015] [Accepted: 10/30/2015] [Indexed: 10/22/2022] Open
Abstract
Calcium signaling has long been associated with key events of immunity, including chemotaxis, phagocytosis, and activation. However, imaging and manipulation of calcium flux in motile immune cells in live animals remain challenging. Using light-sheet microscopy for in vivo calcium imaging in zebrafish, we observe characteristic patterns of calcium flux triggered by distinct events, including phagocytosis of pathogenic bacteria and migration of neutrophils toward inflammatory stimuli. In contrast to findings from ex vivo studies, we observe enriched calcium influx at the leading edge of migrating neutrophils. To directly manipulate calcium dynamics in vivo, we have developed transgenic lines with cell-specific expression of the mammalian TRPV1 channel, enabling ligand-gated, reversible, and spatiotemporal control of calcium influx. We find that controlled calcium influx can function to help define the neutrophil's leading edge. Cell-specific TRPV1 expression may have broad utility for precise control of calcium dynamics in other immune cell types and organisms.
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14
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Herrmann JM, Meyle J. Neutrophil activation and periodontal tissue injury. Periodontol 2000 2015; 69:111-27. [DOI: 10.1111/prd.12088] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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15
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Ke F, Zhang L, Liu Z, Liu J, Yan S, Xu Z, Bai J, Zhu H, Lou F, Wang H, Shi Y, Jiang Y, Su B, Wang H. Autocrine interleukin-6 drives skin-derived mesenchymal stem cell trafficking via regulating voltage-gated Ca(2+) channels. Stem Cells 2015; 32:2799-810. [PMID: 24906203 DOI: 10.1002/stem.1763] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 04/01/2014] [Accepted: 04/09/2014] [Indexed: 12/13/2022]
Abstract
Mesenchymal stem cells (MSCs) have demonstrated promising therapeutic potential for a variety of diseases including autoimmune disorders. A fundamental requirement for MSC-mediated in vivo immunosuppression is their effective trafficking. However the mechanism underlying MSC trafficking remains elusive. Here we report that skin-derived MSCs (S-MSCs) secrete high levels of interleukin-6 (IL-6) in inflammatory conditions. Disruption of the il6 or its signaling transducer gp130 blocks voltage-gated calcium (Ca(2+) ) channels (VGCC) critically required for cell contraction involved in the sequential adhesion and de-adhesion events during S-MSC migration. Deletion of il6 gene leads to a severe defect in S-MSC's trafficking and immunosuppressive function in vivo. Thus, this unexpected requirement of autocrine IL-6 for activating Ca(2+) channels uncovers a previously unrecognized link between the IL-6 signaling and the VGCC and provides novel mechanistic insights for the trafficking and immunomodulatory activities of S-MSCs.
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Affiliation(s)
- Fang Ke
- Shanghai Institute of Immunology, Institute of Medical Sciences, Institute of Health Sciences, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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16
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Steinckwich N, Myers P, Janardhan KS, Flagler ND, King D, Petranka JG, Putney JW. Role of the store-operated calcium entry protein, STIM1, in neutrophil chemotaxis and infiltration into a murine model of psoriasis-inflamed skin. FASEB J 2015; 29:3003-13. [PMID: 25837581 DOI: 10.1096/fj.14-265215] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 03/09/2015] [Indexed: 12/27/2022]
Abstract
Stromal interaction molecule 1 (STIM1) is a Ca(2+) sensor protein that initiates store-operated calcium entry (SOCE). STIM1 is known to be involved in the chemoattractant signaling pathway for FPR1 in cell lines, but its role in in vivo functioning of neutrophils is unclear. Plaque-type psoriasis is a chronic inflammatory skin disorder associated with chemoattractants driving neutrophils into the epidermis. We investigated the involvement of STIM1 in neutrophil chemotaxis in vitro, as well as during chronic psoriatic inflammation. To this end, we used conditional knockout (KO) mice lacking STIM1 in cells of myeloid lineage (STIM1(fl/fl) LysM-cre). We demonstrate that STIM1 is required for chemotaxis because of multiple chemoattractants in mouse neutrophils in vitro. Using an imiquimod-induced psoriasis-like skin model, we show that KO mice had less neutrophil infiltration in the epidermis than controls, whereas neither chemoattractant production in the epidermis nor macrophage migration was decreased. KO mice displayed a more rapid reversal of the outward signs of psoriasis (plaques). Thus, KO of STIM1 impairs neutrophil contribution to psoriatic inflammation. Our data provide new insights to our understanding of how STIM1 orchestrates the cellular behavior underlying chemotaxis and illustrate the important role of SOCE in a disease-related pathologic model.
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Affiliation(s)
- Natacha Steinckwich
- *Signal Transduction Laboratory, Comparative Medicine Branch, Integrated Laboratory Systems, Incorporated, Cellular and Molecular Pathology Branch,National Toxicology Program, and Special Techniques Group, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - Page Myers
- *Signal Transduction Laboratory, Comparative Medicine Branch, Integrated Laboratory Systems, Incorporated, Cellular and Molecular Pathology Branch,National Toxicology Program, and Special Techniques Group, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - Kyathanahalli S Janardhan
- *Signal Transduction Laboratory, Comparative Medicine Branch, Integrated Laboratory Systems, Incorporated, Cellular and Molecular Pathology Branch,National Toxicology Program, and Special Techniques Group, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - Norris D Flagler
- *Signal Transduction Laboratory, Comparative Medicine Branch, Integrated Laboratory Systems, Incorporated, Cellular and Molecular Pathology Branch,National Toxicology Program, and Special Techniques Group, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - Debra King
- *Signal Transduction Laboratory, Comparative Medicine Branch, Integrated Laboratory Systems, Incorporated, Cellular and Molecular Pathology Branch,National Toxicology Program, and Special Techniques Group, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - John G Petranka
- *Signal Transduction Laboratory, Comparative Medicine Branch, Integrated Laboratory Systems, Incorporated, Cellular and Molecular Pathology Branch,National Toxicology Program, and Special Techniques Group, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - James W Putney
- *Signal Transduction Laboratory, Comparative Medicine Branch, Integrated Laboratory Systems, Incorporated, Cellular and Molecular Pathology Branch,National Toxicology Program, and Special Techniques Group, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
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17
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Aniket, Reid R, Hall B, Marriott I, El-Ghannam A. Early osteoblast responses to orthopedic implants: Synergy of surface roughness and chemistry of bioactive ceramic coating. J Biomed Mater Res A 2014; 103:1961-73. [DOI: 10.1002/jbm.a.35326] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 08/24/2014] [Accepted: 09/03/2014] [Indexed: 12/22/2022]
Affiliation(s)
- Aniket
- Department of Mechanical Engineering and Materials Science; Duke University; Durham North Carolina 27708
| | - Robert Reid
- Department of Bioinformatics and Genomics; University of North Carolina at Charlotte; Charlotte North Carolina 28223
| | - Benika Hall
- Department of Bioinformatics and Genomics; University of North Carolina at Charlotte; Charlotte North Carolina 28223
| | - Ian Marriott
- Department of Biology; University of North Carolina at Charlotte; Charlotte North Carolina 28223
| | - Ahmed El-Ghannam
- Department of Mechanical Engineering and Engineering Science; University of North Carolina at Charlotte; Charlotte North Carolina 28223
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18
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Morin TR, Ghassem-Zadeh SA, Lee J. Traction force microscopy in rapidly moving cells reveals separate roles for ROCK and MLCK in the mechanics of retraction. Exp Cell Res 2014; 326:280-94. [PMID: 24786318 DOI: 10.1016/j.yexcr.2014.04.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 04/15/2014] [Accepted: 04/18/2014] [Indexed: 01/13/2023]
Abstract
Retraction is a major rate-limiting step in cell motility, particularly in slow moving cell types that form large stable adhesions. Myosin II dependent contractile forces are thought to facilitate detachment by physically pulling up the rear edge. However, retraction can occur in the absence of myosin II activity in cell types that form small labile adhesions. To investigate the role of contractile force generation in retraction, we performed traction force microscopy during the movement of fish epithelial keratocytes. By correlating changes in local traction stress at the rear with the area retracted, we identified four distinct modes of retraction. "Recoil" retractions are preceded by a rise in local traction stress, while rear edge is temporarily stuck, followed by a sharp drop in traction stress upon detachment. This retraction type was most common in cells generating high average traction stress. In "pull" type retractions local traction stress and area retracted increase concomitantly. This was the predominant type of retraction in keratocytes and was observed mostly in cells generating low average traction stress. "Continuous" type retractions occur without any detectable change in traction stress, and are seen in cells generating low average traction stress. In contrast, to many other cell types, "release" type retractions occur in keratocytes following a decrease in local traction stress. Our identification of distinct modes of retraction suggests that contractile forces may play different roles in detachment that are related to rear adhesion strength. To determine how the regulation of contractility via MLCK or Rho kinase contributes to the mechanics of detachment, inhibitors were used to block or augment these pathways. Modulation of MLCK activity led to the most rapid change in local traction stress suggesting its importance in regulating attachment strength. Surprisingly, Rho kinase was not required for detachment, but was essential for localizing retraction to the rear. We suggest that in keratocytes MLCK and Rho kinase play distinct, complementary roles in the respective temporal and spatial control of rear detachment that is essential for maintaining rapid motility.
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Affiliation(s)
- Timothy R Morin
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, CT 06269, USA
| | - Sean A Ghassem-Zadeh
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, CT 06269, USA
| | - Juliet Lee
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, CT 06269, USA.
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19
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Branham-O'Connor M, Robichaux WG, Zhang XK, Cho H, Kehrl JH, Lanier SM, Blumer JB. Defective chemokine signal integration in leukocytes lacking activator of G protein signaling 3 (AGS3). J Biol Chem 2014; 289:10738-10747. [PMID: 24573680 DOI: 10.1074/jbc.m113.515031] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activator of G-protein signaling 3 (AGS3, gene name G-protein signaling modulator-1, Gpsm1), an accessory protein for G-protein signaling, has functional roles in the kidney and CNS. Here we show that AGS3 is expressed in spleen, thymus, and bone marrow-derived dendritic cells, and is up-regulated upon leukocyte activation. We explored the role of AGS3 in immune cell function by characterizing chemokine receptor signaling in leukocytes from mice lacking AGS3. No obvious differences in lymphocyte subsets were observed. Interestingly, however, AGS3-null B and T lymphocytes and bone marrow-derived dendritic cells exhibited significant chemotactic defects as well as reductions in chemokine-stimulated calcium mobilization and altered ERK and Akt activation. These studies indicate a role for AGS3 in the regulation of G-protein signaling in the immune system, providing unexpected venues for the potential development of therapeutic agents that modulate immune function by targeting these regulatory mechanisms.
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Affiliation(s)
- Melissa Branham-O'Connor
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425
| | - William G Robichaux
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Xian-Kui Zhang
- Department of Medicine, Division of Rheumatology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Hyeseon Cho
- B-cell Section, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - John H Kehrl
- B-cell Section, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - Stephen M Lanier
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Joe B Blumer
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425.
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20
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Ma S, Cai C, Ma Y, Bai Z, Meng X, Yang X, Zou F, Ge R. Store-operated Ca²⁺ entry mediated regulation of polarization in differentiated human neutrophil-like HL-60 cells under hypoxia. Mol Med Rep 2014; 9:819-24. [PMID: 24425141 DOI: 10.3892/mmr.2014.1894] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 11/06/2013] [Indexed: 11/05/2022] Open
Abstract
The regulation of neutrophil polarization by calcium entry is critical for maintaining an effective host response. Hypoxia has a major effect on the apoptosis of neutrophils, however the role of store-operated Ca2+ entry (SOCE) in neutrophil polarization under hypoxia remains to be elucidated. In the present study, we examined the polarization of differentiated human neutrophil-like HL-60 (dHL-60) cells exposed to hypoxia (3% O2) and the results demonstrated that the percentage of polarized cells following exposure to an N-formyl-Met-Leu-Phe (fMLP) gradient in the Zigmond chamber was increased. We examined stromal interaction molecule 1 (STIM1) and Orai1 expression in dHL-60 cells during hypoxia, and it was observed that the expression of STIM1 and Orai1 was significantly reduced at day 2. However, no apparent change was observed on the first day, indicating that this effect is dependent on stimulation time. Fluo-4/acetoxymethyl (AM) ester imaging also demonstrated that SOCE was decreased in dHL-60 cells. The plasmid overexpression assay demonstrated that the response of polarization was returned to the control level. We demonstrated the inhibitory role of SOCE on the polarization of dHL-60 cells under hypoxic conditions, which may be the mechanism for the adaptation of neutrophils to hypoxia. SOCE is also suggested to be a key modulator of immune deficiency under hypoxic conditions and is potentially a therapeutic target.
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Affiliation(s)
- Shuang Ma
- Research Centre for High Altitude Medicine, Qinghai University Medical College, Qinghai University, Xining, Qinghai 810000, P.R. China
| | - Chunqing Cai
- Department of Occupational Health and Occupational Medicine, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Yan Ma
- Research Centre for High Altitude Medicine, Qinghai University Medical College, Qinghai University, Xining, Qinghai 810000, P.R. China
| | - Zhengzhong Bai
- Research Centre for High Altitude Medicine, Qinghai University Medical College, Qinghai University, Xining, Qinghai 810000, P.R. China
| | - Xiaojing Meng
- Department of Occupational Health and Occupational Medicine, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Xinyi Yang
- Department of Occupational Health and Occupational Medicine, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Fei Zou
- Department of Occupational Health and Occupational Medicine, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Rili Ge
- Research Centre for High Altitude Medicine, Qinghai University Medical College, Qinghai University, Xining, Qinghai 810000, P.R. China
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21
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Stock C, Ludwig FT, Hanley PJ, Schwab A. Roles of ion transport in control of cell motility. Compr Physiol 2013; 3:59-119. [PMID: 23720281 DOI: 10.1002/cphy.c110056] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell motility is an essential feature of life. It is essential for reproduction, propagation, embryonic development, and healing processes such as wound closure and a successful immune defense. If out of control, cell motility can become life-threatening as, for example, in metastasis or autoimmune diseases. Regardless of whether ciliary/flagellar or amoeboid movement, controlled motility always requires a concerted action of ion channels and transporters, cytoskeletal elements, and signaling cascades. Ion transport across the plasma membrane contributes to cell motility by affecting the membrane potential and voltage-sensitive ion channels, by inducing local volume changes with the help of aquaporins and by modulating cytosolic Ca(2+) and H(+) concentrations. Voltage-sensitive ion channels serve as voltage detectors in electric fields thus enabling galvanotaxis; local swelling facilitates the outgrowth of protrusions at the leading edge while local shrinkage accompanies the retraction of the cell rear; the cytosolic Ca(2+) concentration exerts its main effect on cytoskeletal dynamics via motor proteins such as myosin or dynein; and both, the intracellular and the extracellular H(+) concentration modulate cell migration and adhesion by tuning the activity of enzymes and signaling molecules in the cytosol as well as the activation state of adhesion molecules at the cell surface. In addition to the actual process of ion transport, both, channels and transporters contribute to cell migration by being part of focal adhesion complexes and/or physically interacting with components of the cytoskeleton. The present article provides an overview of how the numerous ion-transport mechanisms contribute to the various modes of cell motility.
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Affiliation(s)
- Christian Stock
- Institute of Physiology II, University of Münster, Münster, Germany.
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22
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Hübner K, Surovtsova I, Yserentant K, Hänsch M, Kummer U. Ca2+ dynamics correlates with phenotype and function in primary human neutrophils. Biophys Chem 2013; 184:116-25. [PMID: 24262430 DOI: 10.1016/j.bpc.2013.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 09/19/2013] [Accepted: 09/23/2013] [Indexed: 12/11/2022]
Abstract
Central to the immune defense function of neutrophils is to sense, to move and to kill. Neutrophils acquire distinct cellular states necessary to fulfill these functions each associated with a particular phenotype. The cells constituting the neutrophil population are presumably not synchronized with respect to their actual state, e.g. due to maturity or preactivation. It is also likely that they exhibit a different degree of phenotypic plasticity (that is, the ability to switch to a particular state). Calcium is known to play a crucial role in neutrophils such as for cell motility. The present study focuses on characterizing the cell-to-cell variability at the morphological as well as at the level of calcium dynamics by studying single primary human neutrophils. We apply long-term multivariate live cell imaging to (i) characterize neutrophil phenotypes of different functional states, (ii) analyze the distribution of cells being in these states and, (iii) study the individual intracellular calcium response simultaneously with shape changes. We are able to differentiate the five distinct subpopulations of neutrophils based on quantitative parameters of cell morphology and motility. As a major result, we demonstrate that the calcium dynamics of individual cells correlates with their respective functional state. Finally, we see a number of cells that undergo spontaneous phenotypic changes from one cellular state to another. These events are preceded either by exhibiting the calcium dynamics of the future state or by switching to the respective calcium dynamics in parallel to switching the morphology. Based on our results we conclude that specific calcium dynamics carries crucial information for the function and phenotype of neutrophils.
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Affiliation(s)
- Katrin Hübner
- Modeling of Biological Processes, BioQuant, COS Heidelberg, University of Heidelberg, Heidelberg, Germany
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23
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Graham DM, Huang L, Robinson KR, Messerli MA. Epidermal keratinocyte polarity and motility require Ca²⁺ influx through TRPV1. J Cell Sci 2013; 126:4602-13. [PMID: 23943873 DOI: 10.1242/jcs.122192] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Ca(2+) has long been known to play an important role in cellular polarity and guidance. We studied the role of Ca(2+) signaling during random and directed cell migration to better understand whether Ca(2+) directs cell motility from the leading edge and which ion channels are involved in this function by using primary zebrafish keratinocytes. Rapid line-scan and time-lapse imaging of intracellular Ca(2+) (Ca(2+)i) during migration and automated image alignment enabled us to characterize and map the spatiotemporal changes in Ca(2+)i. We show that asymmetric distributions of lamellipodial Ca(2+) sparks are encoded in frequency, not amplitude, and that they correlate with cellular rotation during migration. Directed migration during galvanotaxis increases the frequency of Ca(2+) sparks over the entire lamellipod; however, these events do not give rise to asymmetric Ca(2+)i signals that correlate with turning. We demonstrate that Ca(2+)-permeable channels within these cells are mechanically activated and include several transient receptor potential family members, including TRPV1. Last, we demonstrate that cell motility and Ca(2+)i activity are affected by pharmacological agents that target TRPV1, indicating a novel role for this channel during cell migration.
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Affiliation(s)
- David M Graham
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543, USA
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24
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Saraiva N, Prole DL, Carrara G, Johnson BF, Taylor CW, Parsons M, Smith GL. hGAAP promotes cell adhesion and migration via the stimulation of store-operated Ca2+ entry and calpain 2. ACTA ACUST UNITED AC 2013; 202:699-713. [PMID: 23940116 PMCID: PMC3747308 DOI: 10.1083/jcb.201301016] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Golgi antiapoptotic proteins (GAAPs) are highly conserved Golgi membrane proteins that inhibit apoptosis and promote Ca(2+) release from intracellular stores. Given the role of Ca(2+) in controlling cell adhesion and motility, we hypothesized that human GAAP (hGAAP) might influence these events. In this paper, we present evidence that hGAAP increased cell adhesion, spreading, and migration in a manner that depended on the C-terminal domain of hGAAP. We show that hGAAP increased store-operated Ca(2+) entry and thereby the activity of calpain at newly forming protrusions. These hGAAP-dependent effects regulated focal adhesion dynamics and cell migration. Indeed, inhibition or knockdown of calpain 2 abrogated the effects of hGAAP on cell spreading and migration. Our data reveal that hGAAP is a novel regulator of focal adhesion dynamics, cell adhesion, and migration by controlling localized Ca(2+)-dependent activation of calpain.
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Affiliation(s)
- Nuno Saraiva
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, England, UK
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25
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Zhang J, Wei J, Kanada M, Yan L, Zhang Z, Watanabe H, Terakawa S. Inhibition of store-operated Ca2+ entry suppresses EGF-induced migration and eliminates extravasation from vasculature in nasopharyngeal carcinoma cell. Cancer Lett 2013; 336:390-7. [PMID: 23623984 DOI: 10.1016/j.canlet.2013.03.026] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 03/20/2013] [Accepted: 03/25/2013] [Indexed: 11/30/2022]
Abstract
Store-operated Ca(2+) entry (SOCE) mediates Ca(2+) responses evoked by extracellular signaling molecules to promote increases in cytosolic Ca(2+), thereby triggering downstream signal transduction. Here we demonstrated that either the pharmacological blockage of Ca(2+) influx through SOCE or the knockdown of Orai1, a key molecule of SOCE, suppressed the epidermal growth factor-induced migration by disturbing Ca(2+) signaling in nasopharyngeal carcinoma (NPC) cell. Furthermore, Orai1 depletion led to a delayed cell attachment to the extracellular matrix surface in vitro and eliminated the extravasation of microinjected cells from vasculature in a zebrafish hematogenous metastasis model. Our findings thus indicate that SOCE acts as a predominant Ca(2+) signaling involved in NPC cell metastasis, and may serve as a candidate target for anti-metastasis therapy in NPC.
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Affiliation(s)
- Jinyan Zhang
- Medical Photonics Research Center, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu 431-3192, Japan
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26
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Differential regulation of chemotaxis: Role of Gβγ in chemokine receptor-induced cell migration. Cell Signal 2013; 25:729-35. [DOI: 10.1016/j.cellsig.2012.12.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/17/2012] [Accepted: 12/21/2012] [Indexed: 01/17/2023]
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27
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Derouiche S, Warnier M, Mariot P, Gosset P, Mauroy B, Bonnal JL, Slomianny C, Delcourt P, Prevarskaya N, Roudbaraki M. Bisphenol A stimulates human prostate cancer cell migration via remodelling of calcium signalling. SPRINGERPLUS 2013; 2:54. [PMID: 23450760 PMCID: PMC3581770 DOI: 10.1186/2193-1801-2-54] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 02/04/2013] [Indexed: 11/26/2022]
Abstract
Bisphenol A (BPA), the principal constituent of reusable water bottles, metal cans, and plastic food containers, has been shown to be involved in human prostate cancer (PCa) cell proliferation. The aim of the present study was to explore the effect of BPA on PCa cell migration and the pathways involved in these processes. Using the transwell technique, we clearly show for the first time that the pre-treatment of the cells with BPA (1–10 nM) induces human PCa cell migration. Using a calcium imaging technique, we show that BPA pre-treatment induces an amplification of Store-Operated Calcium Entry (SOCE) in LNCaP cells. RT-PCR and Western blot experiments allowed the identification of the ion channel proteins which are up-regulated by BPA pre-treatments. These include the Orai1 protein, which is known as an important SOCE actor in various cell systems, including human PCa cells. Using a siRNA strategy, we observed that BPA-induced amplification of SOCE was Orai1-dependent. Interestingly, the BPA-induced PCa cell migration was suppressed when the calcium entry was impaired by the use of SOCE inhibitors (SKF96365, BTP2), or when the extracellular calcium was chelated. Taken together, the results presented here show that BPA induces PCa cells migration via a modulation of the ion channel protein expression involved in calcium entry and in cancer cell migration. The present data provide novel insights into the molecular mechanisms involved in the effects of an environmental factor on cancer cells and suggest both the necessity of preventive measures and the possibility of targeting ion channels in the treatment of PCa cell metastasis.
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Affiliation(s)
- Sandra Derouiche
- Inserm, U-1003, Equipe labellisée par la Ligue Nationale contre le cancer, Villeneuve d'Ascq, France ; Laboratory of Excellence, Ion Channels Science and Therapeutics; Université Lille I Sciences et Technologies, Villeneuve d'Ascq, France
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28
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Schwab A, Fabian A, Hanley PJ, Stock C. Role of ion channels and transporters in cell migration. Physiol Rev 2013; 92:1865-913. [PMID: 23073633 DOI: 10.1152/physrev.00018.2011] [Citation(s) in RCA: 315] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cell motility is central to tissue homeostasis in health and disease, and there is hardly any cell in the body that is not motile at a given point in its life cycle. Important physiological processes intimately related to the ability of the respective cells to migrate include embryogenesis, immune defense, angiogenesis, and wound healing. On the other side, migration is associated with life-threatening pathologies such as tumor metastases and atherosclerosis. Research from the last ≈ 15 years revealed that ion channels and transporters are indispensable components of the cellular migration apparatus. After presenting general principles by which transport proteins affect cell migration, we will discuss systematically the role of channels and transporters involved in cell migration.
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29
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Dixit N, Kim MH, Rossaint J, Yamayoshi I, Zarbock A, Simon SI. Leukocyte function antigen-1, kindlin-3, and calcium flux orchestrate neutrophil recruitment during inflammation. THE JOURNAL OF IMMUNOLOGY 2012; 189:5954-64. [PMID: 23144497 DOI: 10.4049/jimmunol.1201638] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Neutrophil arrest and migration on inflamed endothelium involves a conformational shift in CD11a/CD18 (leukocyte function antigen-1; LFA-1) to a high-affinity and clustered state that determines the strength and lifetime of bond formation with ICAM-1. Cytoskeletal adapter proteins Kindlin-3 and Talin-1 anchor clustered LFA-1 to the cytoskeleton and facilitate the transition from neutrophil rolling to arrest. We recently reported that tensile force acts on LFA-1 bonds inducing their colocalization with Orai1, the predominant membrane store operated Ca(2+) channel that cooperates with the endoplasmic reticulum to elicit cytosolic flux. Because Kindlin-3 was recently reported to initiate LFA-1 clustering in lymphocytes, we hypothesized that it cooperates with Orai1 and LFA-1 in signaling local Ca(2+) flux necessary for shear-resistant neutrophil arrest. Using microfluidic flow channels combined with total internal reflection fluorescence microscopy, we applied defined shear stress to low- or high-affinity LFA-1 and imaged the spatiotemporal regulation of bond formation with Kindlin-3 recruitment and Ca(2+) influx. Orai1 and Kindlin-3 genes were silenced in neutrophil-like HL-60 cells to assess their respective roles in this process. Kindlin-3 was enriched within focal clusters of high-affinity LFA-1, which promoted physical linkage with Orai1. This macromolecular complex functioned to amplify inside-out Ca(2+) signaling in response to IL-8 stimulation by catalyzing an increased density of Talin-1 and consolidating LFA-1 clusters within sites of contact with ICAM-1. In this manner, neutrophils use focal adhesions as mechanosensors that convert shear stress-mediated tensile force into local bursts of Ca(2+) influx that catalyze cytoskeletal engagement and an adhesion-strengthened migratory phenotype.
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Affiliation(s)
- Neha Dixit
- Department of Biomedical Engineering, University of California, Davis, Davis, CA 95616, USA
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Lee J, Veatch SL, Baird B, Holowka D. Molecular mechanisms of spontaneous and directed mast cell motility. J Leukoc Biol 2012; 92:1029-41. [PMID: 22859829 PMCID: PMC3476239 DOI: 10.1189/jlb.0212091] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 07/02/2012] [Accepted: 07/16/2012] [Indexed: 01/01/2023] Open
Abstract
Migration is a fundamental function of immune cells, and a role for Ca(2+) in immune cell migration has been an interest of scientific investigations for many decades. Mast cells are the major effector cells in IgE-mediated immune responses, and cross-linking of IgE-FcεRI complexes at the mast cell surface by antigen activates a signaling cascade that causes mast cell activation, resulting in Ca(2+) mobilization and granule exocytosis. These cells are known to accumulate at sites of inflammation in response to parasite and bacterial infections. Using real-time imaging, we monitored chemotactic migration of RBL and rat BMMCs in response to a gradient of soluble multivalent antigen. Here, we show that Ca(2+) influx via Orai1 plays an important role in regulating spontaneous motility and directional migration of mast cells toward antigen via IgER complexes. Inhibition of Ca(2+) influx or knockdown of the Ca(2+) entry channel protein Orai1 by shRNA causes inhibition of both of these processes. In addition, a mutant Syk- shows impaired spontaneous motility and chemotaxis toward antigen that is rescued by expression of Syk. Our findings identify a novel Ca(2+) influx-mediated, Orai1-dependent mechanism for mast cell migration.
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Affiliation(s)
- Jinmin Lee
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA
| | | | - Barbara Baird
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA
| | - David Holowka
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA
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Song S, Li J, Zhu L, Cai L, Xu Q, Ling C, Su Y, Hu Q. Irregular Ca(2+) oscillations regulate transcription via cumulative spike duration and spike amplitude. J Biol Chem 2012; 287:40246-55. [PMID: 23071118 DOI: 10.1074/jbc.m112.417154] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND [Ca(2+)](i) oscillations are irregular and heterogeneous. RESULTS The correlations between NFκB/STAT3-GFP transcription and [Ca(2+)](i) spike amplitude/cumulative spike duration are revealed by simultaneous monitoring in single cells and validated in cell population. CONCLUSION [Ca(2+)](i) oscillations regulate transcription through [Ca(2+)](i) spike amplitude and cumulative spike duration. SIGNIFICANCE How irregular [Ca(2+)](i) oscillations control transcription is crucial for understanding biological [Ca(2+)](i) signal-regulated events. Agonist-stimulated [Ca(2+)](i) oscillations are universally irregular in their kinetics. How irregular [Ca(2+)](i) oscillations dynamically regulate agonist-stimulated downstream events has not been studied. To overcome the obstacles of irregularity and heterogeneity of [Ca(2+)](i) oscillations, agonist-stimulated [Ca(2+)](i) signaling and NFκB/STAT3-GFP nuclear translocation were simultaneously monitored in each single cell examined. The cause-effect relationship between [Ca(2+)](i) oscillation parameters and transcriptional activities was validated in cell populations through irregular [Ca(2+)](i) oscillations with varied parameters. The time duration of cumulative [Ca(2+)](i) elevations reaching the threshold [Ca(2+)](i) level for a transcriptional factor activation and [Ca(2+)](i) spike amplitude was found to control agonist-stimulated transcription and gene expression.
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Affiliation(s)
- Shanshan Song
- Department of Pathophysiology, School of Public Health, Tongji Medical College, Huazhong Science and Technology University, Wuhan 430030, People's Republic of China
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Rescue of neuronal migration deficits in a mouse model of fetal Minamata disease by increasing neuronal Ca2+ spike frequency. Proc Natl Acad Sci U S A 2012; 109:5057-62. [PMID: 22411806 DOI: 10.1073/pnas.1120747109] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the brains of patients with fetal Minamata disease (FMD), which is caused by exposure to methylmercury (MeHg) during development, many neurons are hypoplastic, ectopic, and disoriented, indicating disrupted migration, maturation, and growth. MeHg affects a myriad of signaling molecules, but little is known about which signals are primary targets for MeHg-induced deficits in neuronal development. In this study, using a mouse model of FMD, we examined how MeHg affects the migration of cerebellar granule cells during early postnatal development. The cerebellum is one of the most susceptible brain regions to MeHg exposure, and profound loss of cerebellar granule cells is detected in the brains of patients with FMD. We show that MeHg inhibits granule cell migration by reducing the frequency of somal Ca(2+) spikes through alterations in Ca(2+), cAMP, and insulin-like growth factor 1 (IGF1) signaling. First, MeHg slows the speed of granule cell migration in a dose-dependent manner, independent of the mode of migration. Second, MeHg reduces the frequency of spontaneous Ca(2+) spikes in granule cell somata in a dose-dependent manner. Third, a unique in vivo live-imaging system for cell migration reveals that reducing the inhibitory effects of MeHg on somal Ca(2+) spike frequency by stimulating internal Ca(2+) release and Ca(2+) influxes, inhibiting cAMP activity, or activating IGF1 receptors ameliorates the inhibitory effects of MeHg on granule cell migration. These results suggest that alteration of Ca(2+) spike frequency and Ca(2+), cAMP, and IGF1 signaling could be potential therapeutic targets for infants with MeHg intoxication.
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Adams SE, Parr C, Miller DJ, Allemann RK, Hallett MB. Potent inhibition of Ca2+-dependent activation of calpain-1 by novel mercaptoacrylates. MEDCHEMCOMM 2012. [DOI: 10.1039/c2md00280a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Hambrecht A, Jandial R, Neman J. Emerging role of brain metastases in the prognosis of breast cancer patients. BREAST CANCER-TARGETS AND THERAPY 2011; 3:79-91. [PMID: 24367178 DOI: 10.2147/bctt.s19967] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cancer starts with one rogue cell. Through mutations and genomic alterations, the cell acquires specific and stem cell-like characteristics necessary for invasion of a distant organ and ultimately metastasis. Metastatic brain cancer is a particularly formidable disease because of its poor prognosis and the highly resistant nature of the tumor to chemotherapy. Although several types of primary tumors have a tendency to metastasize to the brain, the incidence of brain metastases has increased dramatically in some subsets of breast cancer patients. Several conventional treatments are available, but success is limited and often short-lived. Given that no standard treatment options exist, there is a significant need to investigate the biology of these clinically recalcitrant tumors.
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Affiliation(s)
- Amanda Hambrecht
- Department of Biology, University of Southern California ; Department of Neurosurgery, Beckman Research Institute, City of Hope National Cancer Center, CA, USA
| | - Rahul Jandial
- Department of Neurosurgery, Beckman Research Institute, City of Hope National Cancer Center, CA, USA
| | - Josh Neman
- Department of Neurosurgery, Beckman Research Institute, City of Hope National Cancer Center, CA, USA
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Cross-talk between calcium and protein kinase A in the regulation of cell migration. Curr Opin Cell Biol 2011; 23:554-61. [PMID: 21665456 DOI: 10.1016/j.ceb.2011.05.006] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 05/16/2011] [Accepted: 05/17/2011] [Indexed: 12/31/2022]
Abstract
Calcium (Ca(2+)) and the cAMP-dependent protein kinase (PKA) are pleiotropic cellular regulators and both exert powerful, diverse effects on cytoskeletal dynamics, cell adhesion, and cell migration. Localization, by A-kinase-anchoring proteins (AKAPs), of PKA activity to the protrusive leading edge, integrins, and other regulators of cytoskeletal dynamics has emerged as an important facet of its role in cell migration. Additional recent work has firmly established the importance of Ca(2+) influx through mechanosensitive transient receptor potential (TRP) channels and through store-operated Ca(2+) entry (SOCE) in cell migration. Finally, there is considerable evidence showing that these mechanisms of Ca(2+) influx and PKA regulation intersect--and often interact--and thus may work in concert to translate complex extracellular cues into the intracellular biochemical anisotropy required for directional cell migration.
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36
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Extracellular ATP induces spikes in cytosolic free Ca(2+) but not in NADPH oxidase activity in neutrophils. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:1446-52. [PMID: 21596069 DOI: 10.1016/j.bbamcr.2011.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 04/29/2011] [Accepted: 05/02/2011] [Indexed: 01/14/2023]
Abstract
In order to establish whether non-mitochondrial oxidase activity in human neutrophils is tightly related to cytosolic Ca(2+) concentration, we simultaneously measured Ca(2+) oscillations induced by ATP and oxidant production in single adherent neutrophils using confocal microscopy. ATP induced fast damped Ca(2+) spikes with a period of 15s and slower irregular spikes with a period greater than 50s. Spikes in Ca(2+) occurred in the absence of Ca(2+) influx, but the amplitude was damped by inhibition of Ca(2+) influx. Using the oxidation of hydroethidine as a cytosolic marker of oxidant production, we show that the generation of reactive oxygen species by neutrophils adherent to glass was accelerated by ATP. The step-up in NADPH oxidase activity followed the first elevation of cytosolic Ca(2+) but, despite subsequent spikes in Ca(2+) concentration, no oscillations in oxidase activity could be detected. ATP induced spikes in Ca(2+) in a very reproducible way and we propose that the Ca(2+) signal is an on-switch for oxidase activity, but the activity is apparently not directly correlated with spiking activity in cytosolic Ca(2+).
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37
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Selz KA. A third measure-metastable state in the dynamics of spontaneous shape change in healthy human's white cells. PLoS Comput Biol 2011; 7:e1001117. [PMID: 21490721 PMCID: PMC3072360 DOI: 10.1371/journal.pcbi.1001117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 03/04/2011] [Indexed: 12/03/2022] Open
Abstract
Human polymorphonuclear leucocytes, PMN, are highly motile cells with average 12-15 µm diameters and prominent, loboid nuclei. They are produced in the bone marrow, are essential for host defense, and are the most populous of white blood cell types. PMN also participate in acute and chronic inflammatory processes, in the regulation of the immune response, in angiogenesis, and interact with tumors. To accommodate these varied functions, their behavior is adaptive, but still definable in terms of a set of behavioral states. PMN morphodynamics have generally involved a non-equilibrium stationary, spheroid Idling state that transitions to an activated, ellipsoid translocating state in response to chemical signals. These two behavioral shape-states, spheroid and ellipsoid, are generally recognized as making up the vocabulary of a healthy PMN. A third, "random" state has occasionally been reported as associated with disease states. I have observed this third, Treadmilling state, in PMN from healthy subjects, the cells demonstrating metastable dynamical behaviors known to anticipate phase transitions in mathematical, physical, and biological systems. For this study, human PMN were microscopically imaged and analyzed as single living cells. I used a microscope with a novel high aperture, cardioid annular condenser with better than 100 nanometer resolution of simultaneous, mixed dark field and intrinsic fluorescent images to record shape changes in 189 living PMNs. Relative radial roundness, R(t), served as a computable order parameter. Comparison of R(t) series of 10 cells in the Idling and 10 in the Treadmilling state reveals the robustness of the "random" appearing Treadmilling state, and the emergence of behaviors observed in the neighborhood of global state transitions, including increased correlation length and variance (divergence), sudden jumps, mixed phases, bimodality, power spectral scaling and temporal slowing. Wavelet transformation of an R(t) series of an Idling to Treadmilling state change, demonstrated behaviors concomitant with the observed transition.
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Affiliation(s)
- Karen A Selz
- Fetzer Franklin Laboratory of the Cielo Institute, Asheville, North Carolina, USA.
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38
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Costigliola N, Kapustina MT, Weinreb GE, Monteith A, Rajfur Z, Elston TC, Jacobson K. RhoA regulates calcium-independent periodic contractions of the cell cortex. Biophys J 2010; 99:1053-63. [PMID: 20712988 DOI: 10.1016/j.bpj.2010.06.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 05/24/2010] [Accepted: 06/01/2010] [Indexed: 10/19/2022] Open
Abstract
When microtubules are depolymerized in spreading cells, they experience morphological oscillations characterized by a period of about a minute, indicating that normal interactions between the microfilament and microtubule systems have been significantly altered. This experimental system provides a test bed for the development of both fine- and coarse-grained models of complex motile processes, but such models need to be adequately informed by experiment. Using criteria based on Fourier transform analysis, we detect spontaneous oscillations in spreading cells. However, their amplitude and tendency to operate at a single frequency are greatly enhanced by microtubule depolymerization. Knockdown of RhoA and addition of various inhibitors of the downstream effector of RhoA, Rho kinase, block oscillatory behavior. Inhibiting calcium fluxes from endoplasmic reticulum stores and from the extracellular medium does not significantly affect the ability of cells to oscillate, indicating that calcium plays a subordinate regulatory role compared to Rho. We characterized the dynamic structure of the oscillating cell by light, fluorescence, and electron microscopy, showing how oscillating cells are dynamically polarized in terms of their overall morphology, f-actin and phosphorylated myosin light chain distribution, and nuclear position and shape. Not only will these studies guide future experiments, they will also provide a framework for the development of refined mathematical models of the oscillatory process.
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Affiliation(s)
- Nancy Costigliola
- Department of Cell and Developmental Biology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
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39
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Pantaler E, Lückhoff A. Inhibitors of TRP channels reveal stimulus-dependent differential activation of Ca2+ influx pathways in human neutrophil granulocytes. Naunyn Schmiedebergs Arch Pharmacol 2009; 380:497-507. [PMID: 19894037 DOI: 10.1007/s00210-009-0464-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Accepted: 10/05/2009] [Indexed: 11/28/2022]
Abstract
A pharmacological characterization of Ca(2+) influx pathways in neutrophil granulocytes is problematic because of the lack of specific inhibitors. The activation of transient receptor potential cation channel, subfamily M, member 2 (TRPM2) channels by intracellular adenosine diphosphate ribose (ADPR), well characterized in neutrophils, is reportedly inhibited by 8-bromo-ADPR (8Br-ADPR). TRPM2 is blocked by N-(p-amylcinnamoyl)anthranilic acid (ACA) interfering with the pore, but ACA is as well effective on other transient receptor potential channels, especially transient receptor potential canonical (TRPC) channels. We wished to analyze whether ACA and 8Br-ADPR were suitable probes to demonstrate that different Ca(2+) entry pathways are activated in human neutrophil granulocytes by the receptor-dependent stimuli N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) and platelet-activating factor (PAF) and the receptor-independent thapsigargin. Ca(2+)-influx-related increases in [Ca(2+)](i) were calculated by comparing aliquots of fluo-3-loaded neutrophils in the presence and absence of extracellular Ca(2+). Moreover, Mn(2+) quenching was used in fura-2-loaded cells. We compared 8Br-ADPR with ACA. 8Br-ADPR was exclusively effective when Ca(2+) influx (or Mn(2+) quenching) was induced by fMLP; it did not affect influx when PAF or thapsigargin was the stimulus. ACA inhibited Ca(2+) influx significantly more strongly when this was induced by PAF than by fMLP. Moreover, it reduced thapsigargin-induced Ca(2+) influx. The contribution of TRPM2 to Ca(2+) influx in neutrophils strongly depends on the stimulus; it is sizeable in the case of fMLP and minimal in the case of PAF. PAF induces Ca(2+) entry pathways different from TRPM2; the inhibition by ACA suggests the contribution of channels of the TRPC family.
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Affiliation(s)
- Elena Pantaler
- Institut für Physiologie, Medizinische Fakultät der Reinisch-Westfälischen Technischen Hochschule, Pauwelsstrasse 30, Aachen, Germany
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40
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Cook JE, Becker DL. Gap-Junction Proteins in Retinal Development: New Roles for the “Nexus”. Physiology (Bethesda) 2009; 24:219-30. [DOI: 10.1152/physiol.00007.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Gap-junction channels, the cytoplasmic proteins that associate with them, and the transcriptional networks that regulate them are increasingly being viewed as critical communications hubs for cell signaling in health and disease. As a result, the term “nexus,” which was the original structural name for these focal intercellular links, is coming back into use with new proteomic and transcriptomic meanings. The retina is better understood than any other part of the vertebrate central nervous system in respect of its developmental patterning, its diverse neuronal types and circuits, and the emergence of its definitive structure-function correlations. Thus, studies of the junctional and nonjunctional nexus roles of gap-junction proteins in coordinating retinal development should throw useful light on cell signaling in other developing nervous tissues.
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Affiliation(s)
- Jeremy E. Cook
- Department of Cell and Developmental Biology, University College London, Gower Street, London, United Kingdom
| | - David L. Becker
- Department of Cell and Developmental Biology, University College London, Gower Street, London, United Kingdom
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41
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Elsner J, Roesler J, Emmendörffer A, Zeidler C, Lohmann-Matthes ML, Welte K. Altered function and surface marker expression of neutrophils induced by rhG-CSF treatment in severe congenital neutropenia. Eur J Haematol 2009; 48:10-9. [PMID: 1370419 DOI: 10.1111/j.1600-0609.1992.tb01787.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Neutrophils from patients suffering from severe congenital neutropenia (SCN), who were receiving recombinant human granulocyte colony-stimulating factor (rhG-CSF), were investigated in order to analyze the previously described decrease in chemotaxis. This study demonstrated the decreased chemotaxis to five well-known chemoattractants, FMLP, C5a, IL-8, LTB4 and PAF. To further investigate this impairment of patients' neutrophils, receptors and receptor turnover for chemoattractants were examined using flow cytometry. We found 1) increased FMLP receptor and decreased C5a receptor expression, 2) a normal expression of intracellular FMLP receptors after incubation with PMA, 3) increased loss and decreased re-expression of FMLP receptors after incubation with this peptide, 4) normal expression of adhesion glycoproteins CR3 (CD11b/CD18) and LFA1 (CD11a/CD18), 5) further signs of in vivo preactivation: high expression of Fc gamma-RI (CD64) and Fc gamma-RII (CD32), decreased expression of Fc gamma-RIII (CD16), increased expression of CD14, and low expression of HLA-DR. These data demonstrate that the decrease of chemotaxis of neutrophils from SCN patients is not due: a) to a decrease in the number of intra- or extracellular FMLP receptors; b) to a decrease of adhesion molecules. However, the decreased chemotaxis could result from an altered FMLP receptor turnover. The relevance of the altered Fc gamma-receptor pattern for the in vivo occurrence of side-effects, e.g. the necrotic vasculitis, of G-CSF treatment is discussed.
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MESH Headings
- Antibodies, Monoclonal
- Antigens, Differentiation/drug effects
- Antigens, Differentiation/metabolism
- Antigens, Surface/analysis
- Chemotaxis, Leukocyte/drug effects
- Complement C5a/pharmacology
- Fluorescein-5-isothiocyanate
- Granulocyte Colony-Stimulating Factor/therapeutic use
- HLA-DR Antigens/analysis
- Humans
- Immunoglobulin G
- In Vitro Techniques
- Interleukin-8/pharmacology
- Leukotriene B4/pharmacology
- N-Formylmethionine Leucyl-Phenylalanine/pharmacology
- Neutropenia/blood
- Neutropenia/congenital
- Neutropenia/drug therapy
- Neutrophils/drug effects
- Neutrophils/physiology
- Receptors, Fc/drug effects
- Receptors, Fc/metabolism
- Receptors, Formyl Peptide
- Receptors, IgG
- Receptors, Immunologic/drug effects
- Receptors, Immunologic/metabolism
- Recombinant Proteins/therapeutic use
- Reference Values
- Tetradecanoylphorbol Acetate/pharmacology
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Affiliation(s)
- J Elsner
- Fraunhofer Institute ITA, Department of Immunobiology, Hannover, FRG
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Valeyev NV, Kim JS, Heslop-Harrison JSP, Postlethwaite I, Kotov NV, Bates DG. Computational modelling suggests dynamic interactions between Ca2+, IP3 and G protein-coupled modules are key to robust Dictyostelium aggregation. MOLECULAR BIOSYSTEMS 2009; 5:612-28. [PMID: 19462019 DOI: 10.1039/b822074c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Under conditions of starvation, Dictyostelium cells begin a programme of development during which they aggregate to form a multicellular structure by chemotaxis, guided by propagating waves of cyclic AMP that are relayed robustly from cell to cell. In this paper, we develop and analyse a new model for the intracellular and extracellular cAMP dependent processes that regulate Dictyostelium migration. The model allows, for the first time, a quantitative analysis of the dynamic interactions between calcium, IP(3) and G protein-dependent modules that are shown to be key to the generation of robust cAMP oscillations in Dictyostelium cells. The model provides a mechanistic explanation for the transient increase in cytosolic free Ca(2+) concentration seen in recent experiments with the application of the calmodulin inhibitor calmidazolium (R24571) to Dictyostelium cells, and also allows elucidation of the effects of varying both the conductivity of stretch-activated channels and the concentration of external phosphodiesterase on the oscillatory regime of an individual cell. A rigorous analysis of the robustness of the new model shows that interactions between the different modules significantly reduce the sensitivity of the resulting cAMP oscillations to variations in the kinetics of different Dictyostelium cells, an essential requirement for the generation of the spatially and temporally synchronised chemoattractant cAMP waves that guide Dictyostelium aggregation.
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Affiliation(s)
- Najl V Valeyev
- Systems Biology Lab, Department of Engineering, University of Leicester, University Road, Leicester, UK.
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Yang S, Zhang JJ, Huang XY. Orai1 and STIM1 are critical for breast tumor cell migration and metastasis. Cancer Cell 2009; 15:124-34. [PMID: 19185847 DOI: 10.1016/j.ccr.2008.12.019] [Citation(s) in RCA: 532] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 08/28/2008] [Accepted: 12/29/2008] [Indexed: 11/26/2022]
Abstract
Tumor metastasis is the primary cause of death of cancer patients. Understanding the molecular mechanisms underlying tumor metastasis will provide potential drug targets. We report here that Orai1 and STIM1, both of which are involved in store-operated calcium entry, are essential for breast tumor cell migration in vitro and tumor metastasis in mice. Reduction of Orai1 or STIM1 by RNA interference in highly metastatic human breast cancer cells or treatment with a pharmacological inhibitor of store-operated calcium channels decreased tumor metastasis in animal models. Our data demonstrate a role for Orai1 and STIM1 in tumor metastasis and suggest store-operated calcium entry channels as potential cancer therapeutic targets.
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Affiliation(s)
- Shengyu Yang
- Department of Physiology, Weill Medical College of Cornell University, New York, NY 10065, USA
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Easley CA, Brown CM, Horwitz AF, Tombes RM. CaMK-II promotes focal adhesion turnover and cell motility by inducing tyrosine dephosphorylation of FAK and paxillin. ACTA ACUST UNITED AC 2008; 65:662-74. [PMID: 18613116 DOI: 10.1002/cm.20294] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Transient elevations in Ca2+ have previously been shown to promote focal adhesion disassembly and cell motility through an unknown mechanism. In this study, evidence is provided to show that CaMK-II, a Ca2+/calmodulin dependent protein kinase, influences fibroblast adhesion and motility. TIRF microscopy reveals a dynamic population of CaMK-II at the cell surface in migrating cells. Inhibition of CaMK-II with two mechanistically distinct, membrane permeant inhibitors (KN-93 and myr-AIP) freezes lamellipodial dynamics, accelerates spreading on fibronectin, enlarges paxillin-containing focal adhesions and blocks cell motility. In contrast, constitutively active CaMK-II is not found at the cell surface, reduces cell attachment, eliminates paxillin from focal adhesions and decreases the phospho-tyrosine levels of both FAK and paxillin; all of these events can be reversed with myr-AIP. Thus, both CaMK-II inhibition and constitutive activation block cell motility through over-stabilization or destabilization of focal adhesions, respectively. Coupled with the existence of transient Ca2+ elevations and a dynamic CaMK-II population, these findings provide the first direct evidence that CaMK-II enables cell motility by transiently and locally stimulating tyrosine dephosphorylation of focal adhesion proteins to promote focal adhesion turnover.
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Affiliation(s)
- Charles A Easley
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
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Baron S, Struyf S, Wuytack F, Van Damme J, Missiaen L, Raeymaekers L, Vanoevelen J. Contribution of intracellular Ca2+ stores to Ca2+ signaling during chemokinesis of human neutrophil granulocytes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1793:1041-9. [PMID: 19095014 DOI: 10.1016/j.bbamcr.2008.11.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 11/06/2008] [Accepted: 11/16/2008] [Indexed: 10/21/2022]
Abstract
Extracellular agonists increase the cytosolic free Ca2+ concentration ([Ca2+]c) by Ca2+ influx and by stimulating Ca2+ release from intracellular stores, mainly the endoplasmic reticulum and to a lesser extent also later compartments of the secretory pathway, particularly the Golgi. The Golgi takes up Ca2+ via Sarco/Endoplasmic Reticulum Ca2+ATPases (SERCAs) and the Secretory-Pathway Ca2+ATPases (SPCAs). The endogenous expression of SERCAs and SPCAs neutrophils was demonstrated by Western blotting and immunocytochemistry. Up till now, all cytosolic Ca2+ transients due to intracellular Ca2+ release have been found to originate from SERCA-dependent stores. We found that human neutrophils also present Ca2+ release from a SERCA-independent store. Changes in [Ca2+]c of neutrophils were investigated during chemokinesis induced by chemotactic factors in Ca2+-free solution with and without the SERCA-specific inhibitor thapsigargin. Using N-formyl-methionyl-leucyl-phenylalanine or interleukin-8 as agonists, Ca2+ release from intracellular stores was observed in respectively about 40% and 20% of the neutrophils pre-treated with Ca2+-free solution and thapsigargin. In the latter condition, 20-30% of the cells preserved migratory behaviour. These results indicate that both SERCA-dependent and SERCA-independent (presumably SPCA-dependent) intracellular Ca2+ stores contribute to Ca2+ signaling during chemokinesis of human neutrophil granulocytes.
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Affiliation(s)
- Szilvia Baron
- Laboratory of Ca2+-transport ATPases, Department of Molecular Cell Biology, KULeuven Campus Gasthuisberg, Leuven, Belgium
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46
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Hawthorn extract inhibits human isolated neutrophil functions. Pharmacol Res 2008; 57:445-50. [DOI: 10.1016/j.phrs.2008.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 05/04/2008] [Accepted: 05/04/2008] [Indexed: 11/17/2022]
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Morita K, Saida M, Morioka N, Kitayama T, Akagawa Y, Dohi T. Cyclic ADP-ribose mediates formyl methionyl leucyl phenylalanine (fMLP)-induced intracellular Ca(2+) rise and migration of human neutrophils. J Pharmacol Sci 2008; 106:492-504. [PMID: 18344610 DOI: 10.1254/jphs.fp0072083] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Although cyclic ADP-ribose (cADPR), a novel Ca(2+)-mobilizing mediator, is suggested to be involved in the functions of neutrophils in rodents, its role in human neutrophils remains unclear. The present study examined the ability of cADPR to mobilize Ca(2+) and mediate formyl methionyl leucyl phenylalanine (fMLP)-stimulated increase in cytosolic free Ca(2+) concentration ([Ca(2+)](i)) and migration in human neutrophils. cADPR induced Ca(2+) release from digitonin-permeabilized neutrophils, and the release was blocked by 8Br-cADPR, an antagonist of cADPR. Immunophilin ligands, FK506 and rapamycin, but not cyclosporine A, inhibited cADPR-induced Ca(2+) release. 8Br-cADPR partially reduced fMLP-induced [Ca(2+)](i) rise and abolished the rise in combination with 2APB, an IP(3)-receptor antagonist. Anti-CD38Ab and NADase that interfere with cADPR formation, reduced the fMLP-induced [Ca(2+)](i) rise. When beta-NAD(+), a substrate of ADP-ribosyl cyclase, and cADPR were added to the medium, the former gradually increased [Ca(2+)](i) and the latter potentiated the fMLP-induced [Ca(2+)](i) rise. The beta-NAD(+)-induced [Ca(2+)](i) rise in Ca(2+)-free medium was inhibited by anti-CD38Ab, 8Br-cADPR, FK506, ruthenium red, and thapsigargin. mRNAs of nucleoside transporter (NT), ENT1, ENT2, CNT, and CNT3 were expressed in neutrophils; and their inhibitors, inosine, uridine, and s-(4-nitrobenzyl)-6-thioinosine, reduced the [Ca(2+)](i) rise induced by beta-NAD(+) and fMLP. fMLP-timulated migration was inhibited by the removal of Ca(2+) from the medium or by the addition of 8Br-cADPR, anti-CD38Ab, NADase, and NT inhibitors. These results suggest that cADPR was synthesized extracellularly by CD38, transported into the cells through NTs, and then Ca(2+) was mobilized by FK506-binding protein-dependent process. This process may be involved in fMLP-induced intracellular Ca(2+) signaling and migration in human neutrophils.
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Affiliation(s)
- Katsuya Morita
- Department of Dental Pharmacology, Hiroshima University Graduate School of Biomedical Sciences, Japan
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48
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Thul R, Bellamy TC, Roderick HL, Bootman MD, Coombes S. Calcium oscillations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 641:1-27. [PMID: 18783168 DOI: 10.1007/978-0-387-09794-7_1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Changes in cellular Ca2+ concentration control a wide range of physiological processes, from the subsecond release of synaptic neurotransmitters, to the regulation of gene expression over months or years. Ca2+ can also trigger cell death through both apoptosis and necrosis, and so the regulation of cellular Ca2+ concentration must be tightly controlled through the concerted action of pumps, channels and buffers that transport Ca2+ into and out of the cell cytoplasm. A hallmark of cellular Ca2+ signalling is its spatiotemporal complexity: stimulation of cells by a hormone or neurotransmitter leads to oscillations in cytoplasmic Ca2+ concentration that can vary markedly in time course, amplitude, frequency, and spatial range. In this chapter we review some of the biological roles of Ca2+, the experimental characterisation of complex dynamic changes in Ca2+ concentration, and attempts to explain this complexity using computational models. We consider the 'toolkit' of cellular proteins which influence Ca2+ concentrarion, describe mechanistic models of key elements of the toolkit, and fit these into the framework of whole cell models of Ca2+ oscillations and waves. Finally, we will touch on recent efforts to use stochastic modelling to elucidate elementary Ca2+ signal events, and how these may evolve into global signals.
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Affiliation(s)
- Ruediger Thul
- School of Mathematical Sciences, University of Nottingham, Nottingham, UK
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49
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Evans JH, Falke JJ. Ca2+ influx is an essential component of the positive-feedback loop that maintains leading-edge structure and activity in macrophages. Proc Natl Acad Sci U S A 2007; 104:16176-81. [PMID: 17911247 PMCID: PMC2042181 DOI: 10.1073/pnas.0707719104] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In migrating eukaryotic cells, phosphatidylinositol 3-kinase (PI3K), filamentous actin (F-actin), and monomeric Rho GTPases are key components of a complex positive-feedback system that maintains and amplifies a phosphatidylinositol-3,4,5-trisphosphate signal at the leading edge of the cell. This lipid signal is required for cell polarization and movement. In leukocytes and Dictyostelium, activation or inhibition of any one of these components leads to the activation or inhibition, respectively, of the others via undefined feedback interactions. The role of Ca(2+) signals in migrating leukocytes is controversial, and there has been no indication that Ca(2+) participates in positive feedback. Here, we demonstrate that an extracellular Ca(2+) influx is required for positive feedback at the leading edge of spontaneously polarized macrophages. Inhibition of extracellular Ca(2+) influx leads to loss of leading-edge PI3K activity, disassembly of F-actin, cessation of ruffling, and decay of chemoattractant signals. Conversely, increasing cytosolic Ca(2+) enhances membrane ruffling, PI3K activity, and F-actin accumulation. Overall, these findings demonstrate that an extracellular Ca(2+) influx is an essential component, together with PI3K and F-actin, of the positive-feedback cycle that maintains leading-edge structure and ruffling activity and that supports the chemoattractant response. Strikingly, the Ca(2+)-sensitive enzyme protein kinase Calpha (PKCalpha) is enriched at the leading edge, and its enrichment is sensitive to blockade of Ca(2+) influx, to inhibition of PI3K activity, and to F-actin depolymerization. These findings support the working hypothesis that a local, leading-edge Ca(2+) signal recruits PKCalpha as a central player in the positive-feedback loop.
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Affiliation(s)
- John H. Evans
- *Department of Chemistry and Biochemistry and
- To whom correspondence may be addressed. E-mail: or
| | - Joseph J. Falke
- *Department of Chemistry and Biochemistry and
- the Molecular Biophysics Program, University of Colorado, Boulder, CO 80309-0215
- To whom correspondence may be addressed. E-mail: or
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50
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Fay FS, Gilbert SH, Brundage RA. Calcium signalling during chemotaxis. CIBA FOUNDATION SYMPOSIUM 2007; 188:121-35; discussion 136-40. [PMID: 7587614 DOI: 10.1002/9780470514696.ch8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The role of Ca2+ in chemotaxis of eosinophils from the newt Taricha granulosa was investigated using fluorescent indicators and digital imaging microscopy. In response to serum chemoattractant, cytoplasmic Ca2+ concentration ([Ca2+]i) rises prior to polarization. In polarized locomoting cells [Ca2+]i gradients (tail-high-front-low) are always seen, and when cells turn [Ca2+]i rises transiently and falls fastest and furthest in the new direction of cell motion. These Ca2+ signals, which are required for polarization and locomotion, arise from Ca2+ derived from internal stores released in response to inositol 1,4,5-trisphosphate (InsP3) (because microinjected heparin fully blocks them). 1,2-Diacyl-sn-glycerol (DAG), which is co-produced with InsP3, has an inhibitory effect on Ca2+ signals, an effect apparently mediated by protein kinase C. Studies with caged InsP3 reveal that InsP3-responsive stores appear to be concentrated in the nuclear and microtubule-organizing centre regions and that InsP3 moves so rapidly within the cell that it is effectively a global secondary messenger. Thus, stable [Ca2+] gradients observed during unidirectional migration appear to result from the concentration of InsP3-responsive Ca2+ stores in the rear of the cell. By contrast, we propose that reorientation of the [Ca2+] gradient prior to a change in direction of motion results from the joint actions of InsP3 and DAG, with InsP3 acting as a global secondary messenger stimulating Ca2+ release and DAG, through protein kinase C, acting as a spatially restricted secondary messenger inhibiting [Ca2+] increases locally near the site of chemotactic stimulation.
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Affiliation(s)
- F S Fay
- Department of Physiology, University of Massachusetts Medical School, Worcester 01605, USA
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