1
|
Sialic acid-binding immunoglobulin-like lectin 8 (Siglec-8) is an activating receptor mediating β 2-integrin-dependent function in human eosinophils. J Allergy Clin Immunol 2017; 141:2196-2207. [PMID: 28888781 DOI: 10.1016/j.jaci.2017.08.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 08/01/2017] [Accepted: 08/28/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND Siglec-8 is a CD33 subfamily cell-surface receptor selectively expressed on human eosinophils. After cytokine priming, Siglec-8 mAb or glycan ligand binding causes eosinophil apoptosis associated with reactive oxygen species (ROS) production. Most CD33-related Siglecs function as inhibitory receptors, but the ability of Siglec-8 to stimulate eosinophil ROS production and apoptosis suggests that Siglec-8 might instead function as an activating receptor. OBJECTIVE We sought to determine the role of IL-5 priming and identify the signaling molecules involved in Siglec-8 function for human eosinophils. METHODS We used an mAb and/or a multimeric synthetic sulfated sialoglycan ligand recognizing Siglec-8 in combination with integrin blocking antibodies, pharmacologic inhibitors, phosphoproteomics, and Western blot analysis to define the necessity of various proteins involved in Siglec-8 function for human eosinophils. RESULTS Cytokine priming was required to elicit the unanticipated finding that Siglec-8 engagement promotes rapid β2-integrin-dependent eosinophil adhesion. Also novel was the finding that this adhesion was necessary for subsequent ROS production and apoptosis. Siglec-8-mediated ROS was generated through reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation because pretreatment of eosinophils with catalase (an extracellular superoxide scavenger) or NSC 23766 (a Rac GTPase inhibitor) completely inhibited Siglec-8-mediated eosinophil apoptosis. Finally, engagement of Siglec-8 on IL-5-primed eosinophils resulted in increased phosphorylation of Akt, p38, and c-Jun N-terminal kinase 1 that was also β2-integrin dependent; pharmacologic inhibition of these kinases completely prevented Siglec-8-mediated eosinophil apoptosis. CONCLUSIONS These data demonstrate that Siglec-8 functions uniquely as an activating receptor on IL-5-primed eosinophils through a novel pathway involving regulation of β2-integrin-dependent adhesion, NADPH oxidase, and a subset of protein kinases.
Collapse
|
2
|
Behl T, Kaur I, Kotwani A. Role of leukotrienes in diabetic retinopathy. Prostaglandins Other Lipid Mediat 2015; 122:1-9. [PMID: 26673555 DOI: 10.1016/j.prostaglandins.2015.12.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 09/19/2015] [Accepted: 12/03/2015] [Indexed: 12/25/2022]
Abstract
The pathophysiology of diabetic retinopathy is highly complex and encompasses the detrimental roles of numerous factors/mediators in inducing various molecular pathological alterations. Although the roles of many inflammatory mediators, involved in the progression of this complication, have been thoroughly researched and studied, the part played by leukotrienes remains widely neglected. This review focuses on leukotrienes-induced mediation and aggravation of the pathological pathways, such as inflammation, oxidative stress and retinal angiogenesis, responsible for exhibition of various characteristic events including leukostasis, macular edema, retinal neovascularization and vitreous hemorrhages, hence, marking the advent of diabetic retinopathy. Acknowledging these roles, it might be possible to potentially utilize leukotrienes antagonists for suppressing or reducing the intensity of the mentioned pathological alterations. Hence, leukotrienes antagonists may act as an effective adjuvant therapy either along with other developing novel therapies (such as anti-VEGF or anti-TNF-α therapy), or with the established conventional laser photocoagulation treatment, to provide additional symptomatic relief or, possibly prevent the progression of diabetic retinopathy.
Collapse
Affiliation(s)
- Tapan Behl
- Department of Pharmacology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India.
| | - Ishneet Kaur
- Department of Pharmacy, Chandigarh College of Pharmacy, Mohali, Punjab, India
| | - Anita Kotwani
- Department of Pharmacology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| |
Collapse
|
3
|
Yamasaki M, Iwase M, Kawano K, Sakakibara Y, Suiko M, Nishiyama K. Alpha lipoic acid selectively inhibits proliferation and adhesion to fibronectin of v-H-ras-transformed 3Y1 cells. J Clin Biochem Nutr 2011; 50:234-40. [PMID: 22573927 PMCID: PMC3334378 DOI: 10.3164/jcbn.11-67] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Accepted: 08/08/2011] [Indexed: 12/21/2022] Open
Abstract
Here, we focused on the effects of racemic α-lipoic acid on proliferation and adhesion properties of 3Y1 rat fibroblasts and the v-H-ras-transformed derivative, HR-3Y1-2 cells. Racemic α-lipoic acid inhibited proliferation of HR-3Y1-2 but not 3Y1 cells at 0.3 and 1.0 mM. R-(+)-α-lipoic acid also inhibited proliferation of HR-3Y1-2 cells equivalent to that of racemic α-lipoic acid. In addition, racemic α-lipoic acid decreased intracellular reactive oxygen species levels in HR-3Y1 cells but not 3Y1 cells. Next, we evaluated the effects of racemic α-lipoic acid on cell adhesion to fibronectin. The results indicated that racemic α-lipoic acid decreased adhesive ability of HR-3Y1-2 cells to fibronectin-coated plates. As blocking antibody experiment revealed that β1-integrin plays a key role in cell adhesion in this experimental system, the effects of racemic α-lipoic acid on the expression of β1-integrin were examined. The results indicated that racemic α-lipoic acid selectively downregulated the expression of cell surface β1-integrin expression in HR-3Y1-2 cells. Intriguingly, exogenous hydrogen peroxide upregulated cell surface β1-integrin expression in 3Y1 cells. Taken together, these data suggest that reduction of intracellular reactive oxygen species levels by α-lipoic acid could be an effective means of ameliorating abnormal growth and adhesive properties in v-H-ras transformed cells.
Collapse
Affiliation(s)
- Masao Yamasaki
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki 889-2192, Japan
| | | | | | | | | | | |
Collapse
|
4
|
Kato M, Suzuki M, Hayashi Y, Kimura H. Role of eosinophils and their clinical significance in allergic inflammation. Expert Rev Clin Immunol 2010; 2:121-33. [PMID: 20477093 DOI: 10.1586/1744666x.2.1.121] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Eosinophils are believed to play roles in the pathophysiology of allergic inflammation, such as bronchial asthma. However, recent studies on anti-interleukin-5 monoclonal antibody treatment of asthmatic patients raised the possibility that eosinophils may play only a limited role. More recent studies established that eosinophils are essentially involved in the development of airway remodeling. Moreover, it is theoretically conceivable that eosinophils are a cellular source of lipid mediators, such as cysteinyl leukotrienes or platelet-activating factor in asthma. Even in the absence of interleukin-5, it is likely that the 'T-helper Type 2 network', including a cascade of vascular cell adhesion molecule-1, intercellular cell adhesion molecule-1, CC chemokines, granulocyte-macrophage colony-stimulating factor, for example, can maintain sufficient eosinophilic infiltration and effector functions, such as superoxide anion generation and degranulation. Long-term studies, wherein tissue eosinophils are eliminated effectively will be required to establish the exact roles of these cells in asthma. Finally, the authors will demonstrate that eosinophils have the potential for not only playing detrimental roles but also beneficial ones.
Collapse
Affiliation(s)
- Masahiko Kato
- Gunma Children's Medical Center, Department of Allergy and Immunology, Gunma Children's Medical Center, 779 Shimohakoda, Hokkitsu, Gunma 377-8577, Japan.
| | | | | | | |
Collapse
|
5
|
Mustard oil in "Shibori Daikon" a variety of Japanese radish, selectively inhibits the proliferation of H-ras-transformed 3Y1 cells. Biosci Biotechnol Biochem 2009; 73:2217-21. [PMID: 19809176 DOI: 10.1271/bbb.90322] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cruciferous vegetables and their isothiocyanates are promising foods and agents for cancer prevention. We focus here on the effects of mustard oil (SMO) in a variety of the Japanese radish, Shibori Daikon (Raphanus sativus), on the proliferation of 3Y1 rat fibroblasts and the H-ras-transformed derivative, HR-3Y1-2. SMO (1.6 microg/ml) inhibited the proliferation of HR-3Y1-2, but not 3Y1 after 24 h after treatment. A cell cycle analysis showed that SMO induced G2/M arrest after 6 h, although this effect was not observed 24 h after the treatment. SMO transiently decreased the cellular reduced glutathione level accompanied with up-regulation of the intracellular reactive oxygen species 2-3 h post-treatment. Glutathione ethyl ester and N-acetyl-L-cysteine prevented the growth inhibitory effect of SMO. This mustard oil extract consisted of 95.6% 4-methylthio-3-butenyl isothiocyanate and 4.4% 4-methylthiobutyl isothiocyanate. SMO selectively inhibited H-ras-transformed 3Y1 cells associated with transient oxidative stress via reduced glutathione (GSH) depletion.
Collapse
|
6
|
Zhu X, Learoyd J, Butt S, Zhu L, Usatyuk PV, Natarajan V, Munoz NM, Leff AR. Regulation of eosinophil adhesion by lysophosphatidylcholine via a non-store-operated Ca2+ channel. Am J Respir Cell Mol Biol 2007; 36:585-93. [PMID: 17218614 PMCID: PMC1899330 DOI: 10.1165/rcmb.2006-0391oc] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
We examined the mechanism by which lysophosphatidylcholine (LPC) regulates beta2-integrin-mediated adhesion of eosiniophils. Eosinophils were isolated from blood of mildly atopic volunteers by negative immunomagnetic selection. beta2-integrin-dependent adhesion of eosinophils to plated bovine serum albumin (BSA) was measured by residual eosinophil peroxidase activity. LPC caused maximal adhesion of eosinophils to plated BSA at 4 microM. Lysophosphatidylinositol, which has a similar molecular shape, mimicked the effect of LPC on eosinophil adhesion, while neither lysophosphatidylserine nor lysophosphatidylethanolamine had any effect. Phosphatidylethanolamine, a lipid that has a molecular orientation that is the inverse of LPC, blocked eosinophil adhesion caused by LPC. Unlike platelet-activating factor, a G-protein-coupled receptor agonist, LPC did not cause Ca2+-store depletion, but caused increased Ca2+ influx upon addition of Ca2+ to extracellular medium. This influx was not inhibited by U73122, a phospholipase C inhibitor, demonstrating independence from the G protein-activated phospholipase C pathway. Ca2+ influx was inhibited by either preincubation of phosphotidylethanolamine or La3+, a broad spectrum blocker of cation channels. LPC induced up-regulation of the active conformation of CD11b, which was blocked by preincubation with phosphatidylethanolamine. These data suggest that LPC causes a non-store-operated Ca2+ influx into eosinophils, which subsequently activates CD11b/CD18 to promote eosinophil adhesion.
Collapse
Affiliation(s)
- Xiangdong Zhu
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, MC6076, University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA.
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Yamaguchi T, Suzuki M, Kimura H, Kato M. Role of protein kinase C in eosinophil function. Allergol Int 2006; 55:245-52. [PMID: 17075264 DOI: 10.2332/allergolint.55.245] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Indexed: 11/20/2022] Open
Abstract
Protein kinase C (PKC) isoforms are being elucidated as an increasingly diverse family of enzymes involved in the downstream signal transduction and cell function in various types of cells. To date, 11 PKC isoforms have been identified; they are grouped according to their molecular structure and mode of activation: conventional PKCs (alpha, beta I, beta II, and gamma), novel PKCs (delta, epsilon, mu, theta, and eta), and atypical PKCs (zeta, and iota/lambda). Eosinophils are involved in the pathogenesis of allergic diseases such as bronchial asthma, pollinosis, and atopic dermatitis as well as in the inflammatory response to parasitic infections. Recent studies using selective activators and inhibitors of individual PKC isoforms have revealed that this enzyme is involved in eosinophil dynamics such as cell motility and other functions. However, the role of PKCs in eosinophil functions has been not wholly understood. In this review, we have focused upon and summarized the current knowledge regarding the role of PKC isoforms in eosinophil functions.
Collapse
Affiliation(s)
- Takafumi Yamaguchi
- Gunma Prefectural Institute of Public Health and Environmental Sciences, Gunma, Japan
| | | | | | | |
Collapse
|
8
|
Shin MH, Lee YA, Bae YS, Kita H, Kim Y, Ryu SH. The synthetic chemoattractant peptide WKYMVm induces superoxide production by human eosinophils via the phosphoinositide 3-kinase-mediated activation of ERK1/2. Int Arch Allergy Immunol 2005; 137 Suppl 1:21-6. [PMID: 15947481 DOI: 10.1159/000085428] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Eosinophils play a key role in allergic inflammation and parasitic infections. The synthetic peptide, Trp-Lys-Tyr-Met-Val-D-Met (WKYMVm), has been previously shown to activate eosinophils and thus to enhance respiratory burst through the formyl peptide receptors. OBJECTIVE This study was undertaken to determine the intracellular signaling pathway involved in WKYMVm-stimulated superoxide production by human eosinophils. METHODS Purified eosinophils from peripheral blood were stimulated with various concentrations (10(-3) to 10 microM) of WKYMVm and the involvement of PI3-kinase and MAP kinases in WKYMVm-triggered superoxide production was investigated using pharmacological inhibitors. RESULTS WKYMVm-induced superoxide production by eosinophils was strongly inhibited by pretreatment with the PI3-kinase inhibitor LY294002. In addition, pretreatment with the ERK1/2 kinase inhibitor PD98059 resulted in marked inhibition of superoxide production induced by WKYMVm. Indeed, WKYMVm strongly induced phosphorylation of ERK1/2. The ERK1/2 activation by the peptide was transient and peaked after 2 min of stimulation. Furthermore, ERK1/2 activation by WKYMVm was completely inhibited by pretreatment with the PI3-kinase inhibitor LY294002, but not by the PKC inhibitor Ro-31-8220. CONCLUSION These results suggest that WKYMVm stimulates human eosinophils to induce superoxide production via a PI3-kinase-mediated ERK1/2 pathway.
Collapse
Affiliation(s)
- Myeong Heon Shin
- Department of Parasitology, Institute of Tropical Medicine and Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | | | | | | | | | | |
Collapse
|
9
|
Serezani CHC, Aronoff DM, Jancar S, Mancuso P, Peters-Golden M. Leukotrienes enhance the bactericidal activity of alveolar macrophages against Klebsiella pneumoniae through the activation of NADPH oxidase. Blood 2005; 106:1067-75. [PMID: 15718414 PMCID: PMC1895163 DOI: 10.1182/blood-2004-08-3323] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Leukotrienes (LTs) are lipid mediators that participate in inflammatory diseases and innate immune function. We sought to investigate the importance of LTs in regulating the microbicidal activity of alveolar macrophages (AMs) and the molecular mechanisms by which this occurs. The role of LTs in enhancing AM microbicidal activity was evaluated pharmacologically and genetically using in vitro challenge with Klebsiella pneumoniae. Exogenous LTs increased AM microbicidal activity in a dose- and receptor-dependent manner, and endogenous production of LTs was necessary for optimal killing. Leukotriene B4 (LTB4) was more potent than cysteinyl LTs. An important role for nicotinamide adenine dinucleotide (NADPH) oxidase in LT-induced microbicidal activity was indicated by the fact that bacterial killing was abrogated by the NADPH oxidase inhibitor diphenyleneiodonium (DPI; 10 microM) and in AMs derived from gp91phox-deficient mice. By contrast, LT-induced microbicidal activity was independent of the generation of nitric oxide. LTs increased H2O2 production, and LTB4 was again the more potent agonist. Both classes of LTs elicited translocation of p47phox to the cell membrane, and LTB4 induced phosphorylation of p47phox in a manner dependent on protein kinase C-delta (PKC-delta) activity. In addition, the enhancement of microbicidal activity by LTs was also dependent on PKC-delta activity. Our results demonstrate that LTs, especially LTB4, enhanceAM microbicidal activity through the PKC-delta-dependent activation of NADPH oxidase.
Collapse
Affiliation(s)
- Carlos H C Serezani
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109-0642, USA
| | | | | | | | | |
Collapse
|
10
|
Abstract
Integrin regulation and signaling play a central role in the hemostasis process, particularly at the level of endothelial cells by regulating the contractility and barrier function of these cells and in platelets by controlling adhesion and aggregation at the site of cell injury. Reactive oxygen species (ROS) have emerged as an important mediator both transducing the signals associated with integrin activation and modulating integrin function. Ligation of integrins in endothelial cells and platelets induces activation of the Ras/mitogen-activated protein kinase, nuclear factor-kappaB, and phosphatidylinositol 3-kinase and Rho-GTPases pathways. Following vessel-wall injury and associated with activation and recruitment of platelets, there is a production of ROS concomitant with the stimulation of the blood coagulation. Moreover, ROS are capable of inducing conformational changes in integrins to change their binding affinity and function. This review will explore how ROS have emerged as an important modulator of integrins in coagulation through both outside-in (integrins stimulating ROS production to effect intracellular events) and inside-out signaling (intracellular ROS altering integrin function).
Collapse
Affiliation(s)
- David Gregg
- Division of Cardiology, University of California-San Francisco, USA
| | | | | |
Collapse
|
11
|
Newton R, Holden N. Inhibitors of p38 mitogen-activated protein kinase: potential as anti-inflammatory agents in asthma? BioDrugs 2004; 17:113-29. [PMID: 12641490 DOI: 10.2165/00063030-200317020-00004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Asthma is an inflammatory disease of the airways, which in patients with mild to moderate symptoms is adequately controlled by either beta(2)-adrenoceptor agonists or corticosteroids, or a combination of both. Despite this, there are classes of patients that fail to respond to these treatments. In addition, there is a general trend towards increasing morbidity and mortality due to asthma, which suggests that there is a need for new and improved treatments. The p38 mitogen-activated protein kinases (MAPKs) represent a point of convergence for multiple signalling processes that are activated in inflammation and that impact on a diverse range of events that are important in inflammation. Small molecule pyridinyl imidazole inhibitors of p38 MAPK have proved to be highly effective in reducing various parameters of inflammation, in particular cytokine expression. Like corticosteroids, inhibitors of p38 MAPK appear to be able to repress gene expression at multiple levels, for example, by transcriptional, posttranscriptional and translational repression, and this raises the possibility of a similarly broad spectrum of anti-inflammatory activities. Indeed these molecules have proved to be effective in numerous in vitro and in vivo models of inflammation and septicaemia, which suggests that such compounds may be effective as therapeutic agents against inflammatory disorders. Despite these very promising indications of the possible therapeutic use of p38 MAPK inhibitors, a number of events that are p38-dependent are in fact also beneficial to the resolution or modulation of diseases such as asthma. We conclude that the overall effect of p38 MAPK inhibition would be beneficial in inflammatory diseases such as rheumatoid arthritis and asthma. However, these drugs may result in a complex phenotype that will require careful evaluation. Currently, a number of second or third generation inhibitors of p38 MAPK are being tested in phase I and phase II clinical trials.
Collapse
Affiliation(s)
- Robert Newton
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK.
| | | |
Collapse
|
12
|
Greenaway EC, Sepulveda MF, Cunningham FM, Goode NT. Protein kinase C (PKC) isotype profile in eosinophils from ponies with sweet itch and role in histamine-induced eosinophil activation. Vet Immunol Immunopathol 2003; 96:53-63. [PMID: 14522134 DOI: 10.1016/s0165-2427(03)00161-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Eosinophils have been implicated in the pathogenesis of the seasonal equine allergic skin disease, sweet itch. Protein kinase C (PKC) is involved in regulating eosinophil function and antigen challenge has been reported to alter PKC isotype expression in blood eosinophils from allergic human subjects. Here we have compared the pattern of PKC isotype expression in eosinophils from sweet itch ponies with that in cells from normal ponies both during the active and inactive phases of the disease. A role for PKC in histamine-induced eosinophil activation was also investigated. Conventional PKCs alpha and beta, novel PKCs delta and epsilon and atypical PKCs iota and zeta were identified in eosinophils pooled from four allergic ponies during the inactive phase, when no clinical signs were evident. The PKC isotypes, like those in eosinophils from normal ponies, were located primarily in the particulate fraction of the cell. Isotype expression in cells from normal and allergic animals did not appear to be different. In contrast, during the active phase of the disease, when the sweet itch ponies had clinical signs, the expression of PKCs beta, epsilon and iota in eosinophils from these animals appeared to be increased relative to that in cells from normal ponies. When PKC expression in eosinophils from five individual normal and sweet itch ponies was compared, small, but statistically significant, increases in PKC epsilon and PKCdelta expression were evident in eosinophils from the sweet itch ponies during the active and inactive phases, respectively. The non-selective PKC inhibitors, staurosporine and Ro31-8220, significantly reduced histamine-induced superoxide production. Use of Gö6976, an inhibitor of conventional PKCs, suggested that PKCalpha and/or beta were involved and that there was significantly greater inhibition of the response in eosinophils obtained from sweet itch ponies during the active phase. There was no significant difference in histamine-induced superoxide production by eosinophils from allergic and normal ponies and the functional significance of the increased PKC isotype expression in eosinophils from sweet itch ponies relative to that in cells from healthy animals remains to be established.
Collapse
Affiliation(s)
- E C Greenaway
- Department of Veterinary Basic Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire AL9 7TA, UK
| | | | | | | |
Collapse
|
13
|
Touyz RM, Yao G, Schiffrin EL. c-Src induces phosphorylation and translocation of p47phox: role in superoxide generation by angiotensin II in human vascular smooth muscle cells. Arterioscler Thromb Vasc Biol 2003; 23:981-7. [PMID: 12663375 DOI: 10.1161/01.atv.0000069236.27911.68] [Citation(s) in RCA: 211] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The aim of this study was to determine molecular mechanisms whereby c-Src regulates angiotensin II (Ang II)-mediated NAD(P)H oxidase-derived *O2- in human vascular smooth muscle cells (VSMCs). METHODS AND RESULTS VSMCs from human small arteries were studied. Ang II increased NAD(P)H oxidase-mediated generation of *O2- and H2O2 (P<0.01). PP2, c-Src inhibitor, attenuated these effects by 70% to 80%. Immunoprecipitation of p47phox, followed by immunoblotting with antiphosphoserine antibody, demonstrated a rapid increase (1.5- to 2-fold) in p47phox phosphorylation in Ang II-stimulated cells. This was associated with p47phox translocation from cytosol to membrane, as assessed by immunoblotting and immunofluorescence. PP2 abrogated these effects. Long-term Ang II stimulation (6 to 24 hours) increased NAD(P)H oxidase subunit expression. c-Src inhibition decreased abundance of gp91phox, p22phox, and p47phox. Confirmation of c-Src-dependent regulation of NAD(P)H oxidase was tested in VSMCs from c-Src-/- mice. Ang II-induced *O2- generation was lower in c-Src-/- than c-Src+/+ counterparts. This was associated with decreased p47phox phosphorylation, blunted Ang II-stimulated NAD(P)H oxidase activation, and failure of Ang II to increase subunit expression. CONCLUSIONS c-Src regulates NAD(P)H oxidase-derived *O2- generation acutely by stimulating p47phox phosphorylation and translocation and chronically by increasing protein content of gp91phox, p22phox, and p47phox in Ang II-stimulated cells. These novel findings identify NAD(P)H oxidase subunits, particularly p47phox, as downstream targets of c-Src.
Collapse
MESH Headings
- Angiotensin II/pharmacology
- Animals
- Cells, Cultured/drug effects
- Cells, Cultured/metabolism
- Cortactin
- Enzyme Activation/drug effects
- Enzyme Inhibitors/pharmacology
- Humans
- Mice
- Microfilament Proteins/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- NADPH Oxidases
- Phosphoproteins/metabolism
- Phosphorylation
- Protein Subunits
- Protein Transport
- Proto-Oncogene Proteins pp60(c-src)/antagonists & inhibitors
- Proto-Oncogene Proteins pp60(c-src)/physiology
- Pyrimidines/pharmacology
- Reactive Oxygen Species/metabolism
- Receptor, Angiotensin, Type 1/biosynthesis
- Receptor, Angiotensin, Type 1/genetics
- Superoxides/metabolism
Collapse
Affiliation(s)
- R M Touyz
- Multidisciplinary Research Group on Hypertension, Clinical Research Institute of Montreal, University of Montreal, Montreal, Canada.
| | | | | |
Collapse
|
14
|
Seshiah PN, Weber DS, Rocic P, Valppu L, Taniyama Y, Griendling KK. Angiotensin II stimulation of NAD(P)H oxidase activity: upstream mediators. Circ Res 2002; 91:406-13. [PMID: 12215489 DOI: 10.1161/01.res.0000033523.08033.16] [Citation(s) in RCA: 549] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Angiotensin II (Ang II)-stimulated hypertrophy of vascular smooth muscle cells is mediated by reactive oxygen species (ROS) derived from NAD(P)H oxidases. The upstream signaling mechanisms by which Ang II activates these oxidases are unclear but may include protein kinase C, tyrosine kinases, phosphatidylinositol-3-kinase, and Rac, a small molecular weight G protein. We found that Ang II-stimulated ROS production is biphasic. The first phase occurs rapidly (peak at 30 seconds) and is dependent on protein kinase C activation. The larger second phase of ROS generation (peak at 30 minutes) requires Rac activation, because inhibition of Rac by either Clostridium difficile toxin A or dominant-negative Rac significantly inhibits Ang II-induced ROS production. Phosphatidylinositol-3-kinase inhibitors (wortmannin or LY294002) and the epidermal growth factor (EGF) receptor kinase blocker AG1478 attenuate both Rac activation and ROS generation. The upstream activator of EGF receptor transactivation, c-Src, is also required for ROS generation, because PP1, an Src kinase inhibitor, abrogates the Ang II stimulation of both responses. These results suggest that c-Src, EGF receptor transactivation, phosphatidylinositol-3-kinase, and Rac play important roles in the sustained Ang II-mediated activation of vascular smooth muscle cell NAD(P)H oxidases and provide insight into the integrated signaling mechanisms whereby Ang II stimulation leads to activation of the growth-related NAD(P)H oxidases.
Collapse
MESH Headings
- Androstadienes/pharmacology
- Angiotensin II/pharmacology
- Animals
- Cells, Cultured
- Chromones/pharmacology
- Enzyme Inhibitors/pharmacology
- ErbB Receptors/metabolism
- Flow Cytometry
- Hydrogen Peroxide/metabolism
- Indoles/pharmacology
- Male
- Maleimides/pharmacology
- Morpholines/pharmacology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- NADH, NADPH Oxidoreductases/drug effects
- NADH, NADPH Oxidoreductases/metabolism
- NADPH Oxidases
- Phosphatidylinositol 3-Kinases/metabolism
- Phosphoinositide-3 Kinase Inhibitors
- Protein Kinase C/antagonists & inhibitors
- Protein Kinase C/metabolism
- Pyrazoles/pharmacology
- Pyrimidines/pharmacology
- Rats
- Rats, Sprague-Dawley
- Reactive Oxygen Species/metabolism
- Signal Transduction/drug effects
- Time Factors
- Wortmannin
- rac GTP-Binding Proteins/metabolism
- src-Family Kinases/antagonists & inhibitors
- src-Family Kinases/metabolism
Collapse
Affiliation(s)
- Puvi N Seshiah
- Division of Cardiology, Emory University, Atlanta, Ga 30322, USA
| | | | | | | | | | | |
Collapse
|
15
|
Kingham PJ, McLean WG, Sawatzky DA, Walsh MT, Costello RW. Adhesion-dependent interactions between eosinophils and cholinergic nerves. Am J Physiol Lung Cell Mol Physiol 2002; 282:L1229-38. [PMID: 12003778 DOI: 10.1152/ajplung.00278.2001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Eosinophils adhere to airway cholinergic nerves and influence nerve cell function by releasing granule proteins onto inhibitory neuronal M(2) muscarinic receptors. This study investigated the mechanism of eosinophil degranulation by cholinergic nerves. Eosinophils were cocultured with IMR32 cholinergic nerve cells, and eosinophil peroxidase (EPO) or leukotriene C(4) (LTC(4)) release was measured. Coculture of eosinophils with nerves significantly increased EPO and LTC(4) release compared with eosinophils alone. IMR32 cells, like parasympathetic nerves, express the adhesion molecules vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 (ICAM-1). Inhibition of these adhesion molecules alone or in combination significantly inhibited eosinophil degranulation. IMR32 cells also significantly augmented the eosinophil degranulation produced by formyl-Met-Leu-Phe. Eosinophil adhesion to IMR32 cells resulted in an ICAM-1-mediated production of reactive oxygen species via a neuronal NADPH oxidase, inhibition of which significantly inhibited eosinophil degranulation. Additionally, eosinophil adhesion increased the release of ACh from IMR32 cells. These neuroinflammatory cell interactions may be relevant in a variety of inflammatory and neurological conditions.
Collapse
Affiliation(s)
- Paul J Kingham
- Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool L69 3GE, United Kingdom
| | | | | | | | | |
Collapse
|