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Kim KS, Jang JH, Lin H, Choi SW, Kim HR, Shin DH, Nam JH, Zhang YH, Kim SJ. Rise and Fall of Kir2.2 Current by TLR4 Signaling in Human Monocytes: PKC-Dependent Trafficking and PI3K-Mediated PIP2 Decrease. THE JOURNAL OF IMMUNOLOGY 2015; 195:3345-54. [PMID: 26324774 DOI: 10.4049/jimmunol.1500056] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 07/22/2015] [Indexed: 12/24/2022]
Abstract
LPSs are widely used to stimulate TLR4, but their effects on ion channels in immune cells are poorly known. In THP-1 cells and human blood monocytes treated with LPS, inwardly rectifying K(+) channel current (IKir,LPS) newly emerged at 1 h, peaked at 4 h (-119 ± 8.6 pA/pF), and decayed afterward (-32 ± 6.7 pA/pF at 24 h). Whereas both the Kir2.1 and Kir2.2 mRNAs and proteins were observed, single-channel conductance (38 pS) of IKir,LPS and small interfering RNA-induced knockdown commonly indicated Kir2.2 than Kir2.1. LPS-induced cytokine release and store-operated Ca(2+) entry were commonly decreased by ML-133, a Kir2 inhibitor. Immunoblot, confocal microscopy, and the effects of vesicular trafficking inhibitors commonly suggested plasma membrane translocation of Kir2.2 by LPS. Both IKir,LPS and membrane translocation of Kir2.2 were inhibited by GF109203X (protein kinase C [PKC] inhibitor) or by transfection with small interfering RNA-specific PKCε. Interestingly, pharmacological activation of PKC by PMA induced both Kir2.1 and Kir2.2 currents. The spontaneously decayed IKir,LPS at 24 h was recovered by PI3K inhibitors but further suppressed by an inhibitor of phosphatidylinositol(3,4,5)-trisphosphate (PIP3) phosphatase (phosphatase and tensin homolog). However, IKir,LPS at 24 h was not affected by Akt inhibitors, suggesting that the decreased phosphatidylinositol(4,5)-bisphosphate availability, that is, conversion into PIP3 by PI3K, per se accounts for the decay of IKir,LPS. Taken together, to our knowledge these data are the first demonstrations that IKir is newly induced by TLR4 stimulation via PKC-dependent membrane trafficking of Kir2.2, and that conversion of phosphatidylinositol(4,5)-bisphosphate to PIP3 modulates Kir2.2. The augmentation of Ca(2+) influx and cytokine release suggests a physiological role for Kir2.2 in TLR4-stimulated monocytes.
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Affiliation(s)
- Kyung Soo Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Ji Hyun Jang
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Haiyue Lin
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Seong Woo Choi
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Hang Rae Kim
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Dong Hoon Shin
- Division of Natural Medical Sciences, College of Health Science, Chosun University, Gwangju 501-759, Republic of Korea; and
| | - Joo Hyun Nam
- Channelopathy Research Center, Dongguk University College of Medicine, Goyang 410-773, Republic of Korea
| | - Yin Hua Zhang
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Sung Joon Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Channelopathy Research Center, Dongguk University College of Medicine, Goyang 410-773, Republic of Korea
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Anh HN, Hoang VDM, Kudryashova KS, Nekrasova OV, Feofanov AV, Andreeva TV, Tsetlin VI, Utkin YN. Hetlaxin, a new toxin from the Heterometrus laoticus scorpion venom, interacts with voltage-gated potassium channel Kv1.3. DOKL BIOCHEM BIOPHYS 2013; 449:109-11. [DOI: 10.1134/s1607672913020142] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Indexed: 11/23/2022]
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Cox N, Pilling D, Gomer RH. NaCl potentiates human fibrocyte differentiation. PLoS One 2012; 7:e45674. [PMID: 23029177 PMCID: PMC3445484 DOI: 10.1371/journal.pone.0045674] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 08/24/2012] [Indexed: 12/25/2022] Open
Abstract
Excessive NaCl intake is associated with a variety of fibrosing diseases such as renal and cardiac fibrosis. This association has been attributed to increased blood pressure as the result of high NaCl intake. However, studies in patients with high NaCl intake and fibrosis reveal a connection between NaCl intake and fibrosis that is independent of blood pressure. We find that increasing the extracellular concentration of NaCl to levels that may occur in human blood after high-salt intake can potentiate, in serum-free culture conditions, the differentiation of freshly-isolated human monocytes into fibroblast-like cells called fibrocytes. NaCl affects the monocytes directly during their adhesion. Potassium chloride and sodium nitrate also potentiate fibrocyte differentiation. The plasma protein Serum Amyloid P (SAP) inhibits fibrocyte differentiation. High levels of extracellular NaCl change the SAP Hill coefficient from 1.7 to 0.8, and cause a four-fold increase in the concentration of SAP needed to inhibit fibrocyte differentiation by 95%. Together, our data suggest that NaCl potentiates fibrocyte differentiation. NaCl-increased fibrocyte differentiation may thus contribute to NaCl-increased renal and cardiac fibrosis.
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Affiliation(s)
- Nehemiah Cox
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Darrell Pilling
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Richard H. Gomer
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- * E-mail:
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Banquy X, Leclair G, Rabanel JM, Argaw A, Bouchard JF, Hildgen P, Giasson S. Selectins Ligand Decorated Drug Carriers for Activated Endothelial Cell Targeting. Bioconjug Chem 2008; 19:2030-9. [DOI: 10.1021/bc800257m] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Xavier Banquy
- Faculté de Pharmacie, Ecole d’Optométrie, and Département de Chimie, Université de Montréal, and Groupe de Recherche Universitaire sur le Médicament de l’Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, H3C 3J7, Canada, and Merck-Frosst Canada, Kirkland, Québec, Canada
| | - Grégoire Leclair
- Faculté de Pharmacie, Ecole d’Optométrie, and Département de Chimie, Université de Montréal, and Groupe de Recherche Universitaire sur le Médicament de l’Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, H3C 3J7, Canada, and Merck-Frosst Canada, Kirkland, Québec, Canada
| | - Jean-Michel Rabanel
- Faculté de Pharmacie, Ecole d’Optométrie, and Département de Chimie, Université de Montréal, and Groupe de Recherche Universitaire sur le Médicament de l’Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, H3C 3J7, Canada, and Merck-Frosst Canada, Kirkland, Québec, Canada
| | - Anteneh Argaw
- Faculté de Pharmacie, Ecole d’Optométrie, and Département de Chimie, Université de Montréal, and Groupe de Recherche Universitaire sur le Médicament de l’Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, H3C 3J7, Canada, and Merck-Frosst Canada, Kirkland, Québec, Canada
| | - Jean-François Bouchard
- Faculté de Pharmacie, Ecole d’Optométrie, and Département de Chimie, Université de Montréal, and Groupe de Recherche Universitaire sur le Médicament de l’Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, H3C 3J7, Canada, and Merck-Frosst Canada, Kirkland, Québec, Canada
| | - Patrice Hildgen
- Faculté de Pharmacie, Ecole d’Optométrie, and Département de Chimie, Université de Montréal, and Groupe de Recherche Universitaire sur le Médicament de l’Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, H3C 3J7, Canada, and Merck-Frosst Canada, Kirkland, Québec, Canada
| | - Suzanne Giasson
- Faculté de Pharmacie, Ecole d’Optométrie, and Département de Chimie, Université de Montréal, and Groupe de Recherche Universitaire sur le Médicament de l’Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, H3C 3J7, Canada, and Merck-Frosst Canada, Kirkland, Québec, Canada
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Vega-Ostertag ME, Ferrara DE, Romay-Penabad Z, Liu X, Taylor WR, Colden-Stanfield M, Pierangeli SS. Role of p38 mitogen-activated protein kinase in antiphospholipid antibody-mediated thrombosis and endothelial cell activation. J Thromb Haemost 2007; 5:1828-34. [PMID: 17723121 DOI: 10.1111/j.1538-7836.2007.02680.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND The purpose of this study was to examine whether SB 203580, a p38 mitogen-activated protein kinase (MAPK) inhibitor, is effective in reversing the pathogenic effects of antiphospholipid antibodies. METHODS The adhesion of THP-1 monocytes to cultured endothelial cells (EC) treated with immunoglobulin G (IgG) from a patient with antiphospholipid syndrome (IgG-APS) or control IgG (IgG-NHS) in the presence and absence of SB 203580 was examined. The size of an induced thrombus in the femoral vein, the adhesion of leukocytes to EC of cremaster muscle, tissue factor (TF) activity in carotid artery and in peritoneal macrophages, the ex vivo expression of vascular cell adhesion molecule-1 (VCAM-1) in aorta preparations and platelet aggregation were studied in mice injected with IgG-APS or control IgG-NHS and with or without SB 203580. RESULTS SB 203580 significantly reduced the increased adhesion of THP-1 to EC in vitro, the number of leukocytes adhering to EC, the thrombus size, the TF activity in carotid arteries and in peritoneal mononuclear cells, and the expression of VCAM-1 in aorta of mice, and completely abrogated platelet aggregation induced by IgG-APS. CONCLUSION These data suggest that targeting the p38 MAPK pathway may be valuable in designing new therapy modalities for treating thrombosis in patients with APS.
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Affiliation(s)
- M E Vega-Ostertag
- Antiphospholipid Standardization Laboratory, Morehouse School of Medicine, Atlanta, GA, USA
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Kim MJ, Cheng G, Agrawal DK. Cl- channels are expressed in human normal monocytes: a functional role in migration, adhesion and volume change. Clin Exp Immunol 2005; 138:453-9. [PMID: 15544622 PMCID: PMC1809252 DOI: 10.1111/j.1365-2249.2004.02635.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Increased adhesion and diapedesis of monocytes appear to be primary initiating factors in the pathophysiology of occlusive vascular diseases, including atherosclerosis and restenosis. However, the underlying mechanisms of transendothelial migration and invasion of monocytes into the blood vessels are not known. Alterations in ion channels on the cell membrane are generally involved in induced changes in shape and volume. In the present study, we investigated the expression and functional role of chloride channels in freshly isolated human blood monocytes. The Cl- currents in whole-cells were measured by the patch-clamp technique. We observed whole cell Cl- currents, which were time-independent and outwardly rectifying. The chloride channel blockers 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) and R(+)-[(6,7-dichloro-2-cyclopentyl-2,3-dihydro-2-methyl-1-oxo-1H-inden-5yl)-oxy]acetic acid 94 (IAA94) attenuated the Cl- currents. NPPB and IAA94 also inhibited chemotaxis of monocytes, as measured in Boyden chemotactic chambers, with the same sensitivity. NPPB but not IAA94, increased the cell volume as measured by shape change, and decreased tumour necrosis factor (TNF)-alpha-induced monocyte adhesion to endothelial cells. These results suggest that monocytes contain Cl- channels which regulate transendothelial migration of monocytes, due presumably to an alteration in cell volume.
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Affiliation(s)
- M-J Kim
- Department of Biomedical Sciences, University School of Medicine, Omaha, NE 68178, USA
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Vicente R, Escalada A, Coma M, Fuster G, Sánchez-Tilló E, López-Iglesias C, Soler C, Solsona C, Celada A, Felipe A. Differential voltage-dependent K+ channel responses during proliferation and activation in macrophages. J Biol Chem 2003; 278:46307-20. [PMID: 12923194 DOI: 10.1074/jbc.m304388200] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Voltage-dependent K+ channels (VDPC) are expressed in most mammalian cells and involved in the proliferation and activation of lymphocytes. However, the role of VDPC in macrophage responses is not well established. This study was undertaken to characterize VDPC in macrophages and determine their physiological role during proliferation and activation. Macrophages proliferate until an endotoxic shock halts cell growth and they become activated. By inducing a schedule that is similar to the physiological pattern, we have identified the VDPC in non-transformed bone marrow-derived macrophages and studied their regulation. Patch clamp studies demonstrated that cells expressed outward delayed and inwardly rectifying K+ currents. Pharmacological data, mRNA, and protein analysis suggest that these currents were mainly mediated by Kv1.3 and Kir2.1 channels. Macrophage colony-stimulating factor-dependent proliferation induced both channels. Lipopolysaccharide (LPS)-induced activation differentially regulated VDPC expression. While Kv1.3 was further induced, Kir2.1 was down-regulated. TNF-alpha mimicked LPS effects, and studies with TNF-alpha receptor I/II double knockout mice demonstrated that LPS regulation mediates such expression by TNF-alpha-dependent and -independent mechanisms. This modulation was dependent on mRNA and protein synthesis. In addition, bone marrow-derived macrophages expressed Kv1.5 mRNA with no apparent regulation. VDPC activities seem to play a critical role during proliferation and activation because not only cell growth, but also inducible nitric-oxide synthase expression were inhibited by blocking their activities. Taken together, our results demonstrate that the differential regulation of VDPC is crucial in intracellular signals determining the specific macrophage response.
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Affiliation(s)
- Rubén Vicente
- Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Avda. Diagonal 645, E-08028 Barcelona, Spain
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Mackenzie AB, Chirakkal H, North RA. Kv1.3 potassium channels in human alveolar macrophages. Am J Physiol Lung Cell Mol Physiol 2003; 285:L862-8. [PMID: 12909584 DOI: 10.1152/ajplung.00095.2003] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human alveolar macrophages were obtained from macroscopically normal lung tissue obtained at surgical resections, isolated by adherence, and identified by morphology. Whole cell recordings were made from cells 1-3 h in culture, using electrodes containing potassium chloride. From a holding potential of -100 mV, depolarizing pulses to -40 mV or greater activated an outward current. Tail current reversals showed that this current was potassium selective. Margatoxin completely blocked the current; the concentration giving half-maximal block was 160 pM. In current clamp recordings, the resting membrane potential was -34 mV; margatoxin depolarized cells to close to 0 mV. A pure macrophage population was isolated by fluorescence-activated cell sorting, using the phagocytosis of BODIPY-labeled zymosan particles. Reverse transcription-polymerase chain reaction showed that, of 13 voltage-gated K+ (Kv) potassium channels sought, only Kv1.3 mRNA was present. Margatoxin (1 nM) did not affect the percentage of cells showing phagocytosis sorted from the total population. Under these experimental conditions Kv1.3 sets the resting potential of the cells, but it is not required for Fc receptor-mediated phagocytosis.
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Affiliation(s)
- Amanda B Mackenzie
- Inst. of Molecular Physiology, Alfred Denny Bldg., Western Bank, Univ. of Sheffield, Sheffield S10 2TN, United Kingdom
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Espinola RG, Liu X, Colden-Stanfield M, Hall J, Harris EN, Pierangeli SS. E-Selectin mediates pathogenic effects of antiphospholipid antibodies. J Thromb Haemost 2003; 1:843-8. [PMID: 12871424 DOI: 10.1046/j.1538-7836.2003.00119.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Antiphospholipid (aPL) antibodies, detected in patients with antiphospholipid syndrome (APS) are associated with thrombosis, pregnancy loss and thrombocytopenia. Studies have shown that aPL are thrombogenic in vivo, but the mechanism(s) involved are not completely understood. Several studies have demonstrated that aPL antibodies activate endothelial cells (ECs) in vitro, as determined by up-regulation of adhesion molecules: E-selectin (E-sel); intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), and in vivo. The objectives of these study were to determine the effects of aPL antibodies on the expression of E-selectin on ECs, on the adhesion of monocytes to ECs and to study the role of E-selectin on aPL antibodies enhanced thrombus formation and activation of ECs in vivo. We demonstrated that the surface expression of E-selectin on HUVEC by ELISA was increased 400-fold when treated with tumor necrosis factor-alpha (TNF-alpha) and 421-fold when treated with aPL antibodies during 4 h. APL antibodies also induced activation of the nuclear factor-kappa B (NF-kappaB). APL antibodies increased significantly the number of adhering leukocytes to ECs in vivo in C57BL/6 J mice when compared to IgG-NHS treated mice. This effect was abrogated in E-selectin-deficient mice. The thrombus size was significantly increased in C57BL/6 J mice treated with aPL antibodies when compared to mice treated with IgG-NHS. This enhancement in thrombus size by aPL antibodies was abrogated in E-selectin-deficient mice treated with aPL antibodies.
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Affiliation(s)
- R G Espinola
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310, USA
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Preiser JC, Zhang H, Debelle F, Fesler P, Kafi SA, Naeije R, Vincent JL. Hemodynamic effects of glibenclamide during endotoxemia: contrasting findings in vitro versus in vivo. Shock 2003; 19:223-8. [PMID: 12630521 DOI: 10.1097/00024382-200303000-00005] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The final common pathway involved in the cardiovascular alterations of septic shock is incompletely defined. The opening of KATP channels is associated with vasorelaxation and alterations in cardiac contractility. This event may be triggered during septic shock by increased nitric oxide (NO) production, by a decreased intracellular content of ATP, or by a change in the transmembrane electrical potential. In the present study, we assessed the effects of glibenclamide, an agent that blocks the opening of KATP channels in vitro, on the contractile response of rat aortic rings to norepinephrine, and in vivo in anesthetized dogs, with or without exposure to Escherichia coli endotoxin. In vitro, glibenclamide decreased the contractile response to norepinephrine in the presence of endotoxin, provided that the endothelium was intact. In vivo, administration of 0.15 mg/kg increased systemic vascular resistance (SVR) in the absence of endotoxin only, and increased myocardial performance. A higher dose of 1 mg/kg increased SVR and decreased myocardial performance, both during endotoxic shock and in control conditions. Renal and mesenteric blood flows decreased, but the respective fractional flows were unchanged. Oxygen delivery decreased in both experimental conditions, but oxygen consumption decreased only in control conditions. The in vitro observations suggest that the opening of KATP channels is involved in the regulation of vascular tone during endotoxemia, via an endothelium-dependent mechanism. As different effects of glibenclamide were observed in vivo, the importance of the opening of KATP channels in endotoxic shock may be limited.
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Colden-Stanfield M. Clustering of very late antigen-4 integrins modulates K(+) currents to alter Ca(2+)-mediated monocyte function. Am J Physiol Cell Physiol 2002; 283:C990-C1000. [PMID: 12176755 DOI: 10.1152/ajpcell.00481.2001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endothelial cell vascular cell adhesion molecule-1 (VCAM-1) activates adherent monocytes by clustering their very late antigen-4 (VLA-4) receptors, resulting in the modulation of the inwardly rectifying (I(ir)) and delayed rectifying (I(dr)) K(+) currents, hyperpolarization of the cells, and enhanced Ca(2+) influx (Colden-Stanfield M and Gallin EK. Am J Physiol Cell Physiol 275: C267-C277, 1998; Colden-Stanfield M and Scanlon M. Am J Physiol Cell Physiol 279: C488-C494, 2000). The present study was undertaken to test the hypothesis that monoclonal antibodies (MAbs) against VLA-4 (MAbVLA-4) mimic VCAM-1 to cluster VLA-4 integrins, which play a key role in signaling an increase in the secretion of the proinflammatory cytokine interleukin-8 (IL-8). Whole cell ionic currents and IL-8 secretion from THP-1 monocytes that were incubated on polystyrene, VCAM-1-immobilized MAbVLA-4 or an isotype-matched MAb against CD45 (MAbCD45) were measured. Clustering of VLA-4 integrins with a cross-linked MAbVLA-4, but not a monovalent MAbVLA-4, modulated the K(+) currents in an identical manner to incubation of cells on VCAM-1. Similarly, cross-linked MAbVLA-4 or VCAM-1 augmented Ca(2+)-mediated IL-8 secretion from THP-1 monocytes and was completely abolished by exposure to CsCl, an I(ir) blocker. Thus VLA-4 integrin clustering by cross-linked MAbVLA-4 mimics VCAM-1/VLA-4 interactions sufficiently to be associated with events leading to monocyte differentiation, enhanced Ca(2+)-mediated macrophage function, and possibly atherosclerotic plaque formation.
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Chung I, Zelivyanskaya M, Gendelman HE. Mononuclear phagocyte biophysiology influences brain transendothelial and tissue migration: implication for HIV-1-associated dementia. J Neuroimmunol 2002; 122:40-54. [PMID: 11777542 DOI: 10.1016/s0165-5728(01)00462-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mononuclear phagocyte (MP) brain migration influence neuronal damage during HIV-1-associated dementia (HAD). We demonstrate that potassium channels, expressed in human monocyte-derived macrophages (MDM), are vital for MP movement through Boyden chemotactic chambers, an artificial blood-brain barrier and organotypic hippocampal brain slices. MDM migration is inhibited by voltage-and calcium-activated potassium channel blockers that include charybodotoxin, margatoxin, agatoxin and apamin. This is observed both in uninfected and HIV-1-infected MP. The results suggest that potassium channels affect MDM brain migration through altering cell volume and shape. Such mechanisms likely affect MP-induced neuronal destruction during HAD.
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Affiliation(s)
- Induk Chung
- The Center for Neurovirology and Neurodegenerative Disorders, Departments of Pathology and Microbiology, University of Nebraska Medical Center, 985215 Nebraska Medical Center, Omaha, NE 68198-5215, USA
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Colden-Stanfield M, Scanlon M. VCAM-1-induced inwardly rectifying K(+) current enhances Ca(2+) entry in human THP-1 monocytes. Am J Physiol Cell Physiol 2000; 279:C488-94. [PMID: 10913015 DOI: 10.1152/ajpcell.2000.279.2.c488] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hyperpolarization in human leukemia THP-1 monocytes adherent to vascular cell adhesion molecule (VCAM)-1 is due to an induction of inwardly rectifying K(+) currents (I(ir)) (Colden-Stanfield M and Gallin EK, Am J Physiol Cell Physiol 275: C267-C277, 1998). We determined whether the VCAM-1-induced hyperpolarization is sufficient to augment the increase in intracellular free calcium ([Ca(2+)](i)) produced by Ca(2+) store depletion with thapsigargin (TG) and readdition of external CaCl(2) in fura 2-loaded THP-1 monocytes. Whereas there was a 2.1-fold increase in [Ca(2+)](i) in monocytes bound to glass for 5 h in response to TG and CaCl(2) addition, adherence to VCAM-1 produced a 5-fold increase in [Ca(2+)](i). Depolarization of monocytes adherent to VCAM-1 by I(ir) blockade or exposure to high [K(+)] abolished the enhancement of the peak [Ca(2+)](i) response. In monocytes bound to glass, hyperpolarization of the membrane potential with valinomycin, a K(+) ionophore, to the level of hyperpolarization seen in cells adherent to VCAM-1 produced similar changes in peak [Ca(2+)](i). Adherence of monocytes to E-selectin produced a similar peak [Ca(2+)](i) to cells bound to glass. Thus monocyte adherence to the physiological substrate VCAM-1 produces a hyperpolarization that is sufficient to enhance Ca(2+) entry and may impact Ca(2+)-dependent monocyte function.
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Affiliation(s)
- M Colden-Stanfield
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia 30310, USA.
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