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Hammoud MK, Dietze R, Pesek J, Finkernagel F, Unger A, Bieringer T, Nist A, Stiewe T, Bhagwat AM, Nockher WA, Reinartz S, Müller-Brüsselbach S, Graumann J, Müller R. Arachidonic acid, a clinically adverse mediator in the ovarian cancer microenvironment, impairs JAK-STAT signaling in macrophages by perturbing lipid raft structures. Mol Oncol 2022; 16:3146-3166. [PMID: 35451191 PMCID: PMC9441005 DOI: 10.1002/1878-0261.13221] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 03/29/2022] [Accepted: 04/20/2022] [Indexed: 11/08/2022] Open
Abstract
Survival of ovarian carcinoma is associated with the abundance of immunosuppressed CD163highCD206high tumor‐associated macrophages (TAMs) and high levels of arachidonic acid (AA) in the tumor microenvironment. Here, we show that both associations are functionally linked. Transcriptional profiling revealed that high CD163 and CD206/MRC1 expression in TAMs is strongly associated with an inhibition of cytokine‐triggered signaling, mirrored by an impaired transcriptional response to interferons and IL‐6 in monocyte‐derived macrophages by AA. This inhibition of pro‐inflammatory signaling is caused by dysfunctions of the cognate receptors, indicated by the inhibition of JAK1, JAK2, STAT1, and STAT3 phosphorylation, and by the displacement of the interferon receptor IFNAR1, STAT1 and other immune‐regulatory proteins from lipid rafts. AA exposure led to a dramatic accumulation of free AA in lipid rafts, which appears to be mechanistically crucial, as the inhibition of its incorporation into phospholipids did not affect the AA‐mediated interference with STAT1 phosphorylation. Inhibition of interferon‐triggered STAT1 phosphorylation by AA was reversed by water‐soluble cholesterol, known to prevent the perturbation of lipid raft structure by AA. These findings suggest that the pharmacologic restoration of lipid raft functions in TAMs may contribute to the development new therapeutic approaches.
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Affiliation(s)
- Mohamad K Hammoud
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany
| | - Raimund Dietze
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany
| | - Jelena Pesek
- Medical Mass Spectrometry Core Facility, Philipps University, Marburg, Germany
| | - Florian Finkernagel
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany
| | - Annika Unger
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany
| | - Tim Bieringer
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany.,Hochschule Landshut, 84036, Landshut, Germany
| | - Andrea Nist
- Genomics Core Facility, Philipps University, Marburg, Germany
| | - Thorsten Stiewe
- Genomics Core Facility, Philipps University, Marburg, Germany
| | - Aditya M Bhagwat
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany.,The German Centre for Cardiovascular Research (DZHK), Partner Site Rhine-Main, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - W Andreas Nockher
- Medical Mass Spectrometry Core Facility, Philipps University, Marburg, Germany
| | - Silke Reinartz
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany
| | | | - Johannes Graumann
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany.,The German Centre for Cardiovascular Research (DZHK), Partner Site Rhine-Main, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.,Institute for Translational Proteomics, Philipps University, Marburg, Germany
| | - Rolf Müller
- Center for Tumor Biology and Immunology, Philipps University, Marburg, Germany
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2
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Dietze R, Hammoud MK, Gómez-Serrano M, Unger A, Bieringer T, Finkernagel F, Sokol AM, Nist A, Stiewe T, Reinartz S, Ponath V, Preußer C, von Strandmann EP, Müller-Brüsselbach S, Graumann J, Müller R. Phosphoproteomics identify arachidonic-acid-regulated signal transduction pathways modulating macrophage functions with implications for ovarian cancer. Am J Cancer Res 2021; 11:1377-1395. [PMID: 33391540 PMCID: PMC7738879 DOI: 10.7150/thno.52442] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 09/28/2020] [Indexed: 12/17/2022] Open
Abstract
Arachidonic acid (AA) is a polyunsaturated fatty acid present at high concentrations in the ovarian cancer (OC) microenvironment and associated with a poor clinical outcome. In the present study, we have unraveled a potential link between AA and macrophage functions. Methods: AA-triggered signal transduction was studied in primary monocyte-derived macrophages (MDMs) by phosphoproteomics, transcriptional profiling, measurement of intracellular Ca2+ accumulation and reactive oxygen species production in conjunction with bioinformatic analyses. Functional effects were investigated by actin filament staining, quantification of macropinocytosis and analysis of extracellular vesicle release. Results: We identified the ASK1 - p38δ/α (MAPK13/14) axis as a central constituent of signal transduction pathways triggered by non-metabolized AA. This pathway was induced by the Ca2+-triggered activation of calmodulin kinase II, and to a minor extent by ROS generation in a subset of donors. Activated p38 in turn was linked to a transcriptional stress response associated with a poor relapse-free survival. Consistent with the phosphorylation of the p38 substrate HSP27 and the (de)phosphorylation of multiple regulators of Rho family GTPases, AA impaired actin filament organization and inhibited actin-driven macropinocytosis. AA also affected the phosphorylation of proteins regulating vesicle biogenesis, and consistently, AA enhanced the release of tetraspanin-containing exosome-like vesicles. Finally, we identified phospholipase A2 group 2A (PLA2G2A) as the clinically most relevant enzyme producing extracellular AA, providing further potentially theranostic options. Conclusion: Our results suggest that AA contributes to an unfavorable clinical outcome of OC by impacting the phenotype of tumor-associated macrophages. Besides critical AA-regulated signal transduction proteins identified in the present study, PLA2G2A might represent a potential prognostic tool and therapeutic target to interfere with OC progression.
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3
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Gallimore AR, Kim T, Tanaka-Yamamoto K, De Schutter E. Switching On Depression and Potentiation in the Cerebellum. Cell Rep 2019; 22:722-733. [PMID: 29346769 DOI: 10.1016/j.celrep.2017.12.084] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 11/10/2017] [Accepted: 12/22/2017] [Indexed: 12/30/2022] Open
Abstract
Long-term depression (LTD) and long-term potentiation (LTP) in the cerebellum are important for motor learning. However, the signaling mechanisms controlling whether LTD or LTP is induced in response to synaptic stimulation remain obscure. Using a unified model of LTD and LTP at the cerebellar parallel fiber-Purkinje cell (PF-PC) synapse, we delineate the coordinated pre- and postsynaptic signaling that determines the direction of plasticity. We show that LTP is the default response to PF stimulation above a well-defined frequency threshold. However, if the calcium signal surpasses the threshold for CaMKII activation, then an ultrasensitive "on switch" activates an extracellular signal-regulated kinase (ERK)-based positive feedback loop that triggers LTD instead. This postsynaptic feedback loop is sustained by another, trans-synaptic, feedback loop that maintains nitric oxide production throughout LTD induction. When full depression is achieved, an automatic "off switch" inactivates the feedback loops, returning the network to its basal state and demarcating the end of the early phase of LTD.
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Affiliation(s)
- Andrew R Gallimore
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan.
| | - Taegon Kim
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
| | - Keiko Tanaka-Yamamoto
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
| | - Erik De Schutter
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan.
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4
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Qiu YY, Tang LQ, Wei W. Berberine exerts renoprotective effects by regulating the AGEs-RAGE signaling pathway in mesangial cells during diabetic nephropathy. Mol Cell Endocrinol 2017; 443:89-105. [PMID: 28087385 DOI: 10.1016/j.mce.2017.01.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/05/2017] [Accepted: 01/09/2017] [Indexed: 12/20/2022]
Abstract
In this study, we explored the effect of berberine treatment on the AGEs-RAGE pathway in a rat model of diabetic nephropathy, and we investigated the mechanism by which key factors caused kidney injury and the effects of berberine. In vivo, berberine improved fasting blood glucose, body weight, the majority of biochemical and renal function parameters and histopathological changes in the diabetic kidney. Western blotting and immunohistochemistry revealed significant increases in the levels of AGEs, RAGE, P-PKC-β and TGF-β1 in injured kidneys, and these levels were markedly decreased by treatment with berberine. In vitro, berberine inhibited mesangial cell proliferation. Cells treated with berberine showed reduced levels of AGEs, accompanied by decreased RAGE, p-PKC and TGF-β1 levels soon afterwards. Berberine exhibited renoprotective effects in diabetic nephropathy rats, and the molecular mechanism was associated with changes in the levels and regulation of the AGEs-RAGE-PKC-β-TGF-β1 signaling pathway.
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Affiliation(s)
- Yuan-Ye Qiu
- Institute of Clinical Pharmacology, Anhui Medical University, 81#Mei-shan Road, Hefei 230032, Anhui, People's Republic of China; Department of Pharmacy, Anhui Provincial Hospital, Anhui Medical University, 17# Lu-jiang Road, Hefei 230001, Anhui, People's Republic of China.
| | - Li-Qin Tang
- Department of Pharmacy, Anhui Provincial Hospital, Anhui Medical University, 17# Lu-jiang Road, Hefei 230001, Anhui, People's Republic of China.
| | - Wei Wei
- Institute of Clinical Pharmacology, Anhui Medical University, 81#Mei-shan Road, Hefei 230032, Anhui, People's Republic of China.
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Worzfeld T, Pogge von Strandmann E, Huber M, Adhikary T, Wagner U, Reinartz S, Müller R. The Unique Molecular and Cellular Microenvironment of Ovarian Cancer. Front Oncol 2017; 7:24. [PMID: 28275576 PMCID: PMC5319992 DOI: 10.3389/fonc.2017.00024] [Citation(s) in RCA: 174] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/07/2017] [Indexed: 12/13/2022] Open
Abstract
The reciprocal interplay of cancer cells and host cells is an indispensable prerequisite for tumor growth and progression. Cells of both the innate and adaptive immune system, in particular tumor-associated macrophages (TAMs) and T cells, as well as cancer-associated fibroblasts enter into a malicious liaison with tumor cells to create a tumor-promoting and immunosuppressive tumor microenvironment (TME). Ovarian cancer, the most lethal of all gynecological malignancies, is characterized by a unique TME that enables specific and efficient metastatic routes, impairs immune surveillance, and mediates therapy resistance. A characteristic feature of the ovarian cancer TME is the role of resident host cells, in particular activated mesothelial cells, which line the peritoneal cavity in huge numbers, as well as adipocytes of the omentum, the preferred site of metastatic lesions. Another crucial factor is the peritoneal fluid, which enables the transcoelomic spread of tumor cells to other pelvic and peritoneal organs, and occurs at more advanced stages as a malignancy-associated effusion. This ascites is rich in tumor-promoting soluble factors, extracellular vesicles and detached cancer cells as well as large numbers of T cells, TAMs, and other host cells, which cooperate with resident host cells to support tumor progression and immune evasion. In this review, we summarize and discuss our current knowledge of the cellular and molecular interactions that govern this interplay with a focus on signaling networks formed by cytokines, lipids, and extracellular vesicles; the pathophysiologial roles of TAMs and T cells; the mechanism of transcoelomic metastasis; and the cell type selective processing of signals from the TME.
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Affiliation(s)
- Thomas Worzfeld
- Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), Philipps University, Marburg, Germany; Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Elke Pogge von Strandmann
- Experimental Tumor Research, Clinic for Hematology, Oncology and Immunology, Center for Tumor Biology and Immunology, Philipps University , Marburg , Germany
| | - Magdalena Huber
- Institute of Medical Microbiology and Hygiene, Biomedical Research Center, Philipps University , Marburg , Germany
| | - Till Adhikary
- Institute of Molecular Biology and Tumor Research, Center for Tumor Biology and Immunology, Philipps University , Marburg , Germany
| | - Uwe Wagner
- Clinic for Gynecology, Gynecological Oncology and Gynecological Endocrinology, University Hospital of Giessen and Marburg (UKGM) , Marburg , Germany
| | - Silke Reinartz
- Clinic for Gynecology, Gynecological Oncology and Gynecological Endocrinology, Center for Tumor Biology and Immunology (ZTI), Philipps University , Marburg , Germany
| | - Rolf Müller
- Institute of Molecular Biology and Tumor Research, Center for Tumor Biology and Immunology, Philipps University , Marburg , Germany
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6
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Hepburn I, Jain A, Gangal H, Yamamoto Y, Tanaka-Yamamoto K, De Schutter E. A Model of Induction of Cerebellar Long-Term Depression Including RKIP Inactivation of Raf and MEK. Front Mol Neurosci 2017; 10:19. [PMID: 28220061 PMCID: PMC5292618 DOI: 10.3389/fnmol.2017.00019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 01/16/2017] [Indexed: 01/27/2023] Open
Abstract
We report an updated stochastic model of cerebellar Long Term Depression (LTD) with improved realism. Firstly, we verify experimentally that dissociation of Raf kinase inhibitor protein (RKIP) from Mitogen-activated protein kinase kinase (MEK) is required for cerebellar LTD and add this interaction to an earlier published model, along with the known requirement of dissociation of RKIP from Raf kinase. We update Ca2+ dynamics as a constant-rate influx, which captures experimental input profiles accurately. We improve α-amino-3-hydroxy-5-methyl-4 isoxazolepropionic acid (AMPA) receptor interactions by adding phosphorylation and dephosphorylation of AMPA receptors when bound to glutamate receptor interacting protein (GRIP). The updated model is tuned to reproduce experimental Ca2+ peak vs. LTD amplitude curves at four different Ca2+ pulse durations as closely as possible. We find that the updated model is generally more robust with these changes, yet we still observe some sensitivity of LTD induction to copy number of the key signaling molecule Protein kinase C (PKC). We predict natural variability in this number by stochastic diffusion may influence the probabilistic LTD response to Ca2+ input in Purkinje cell spines and propose this as an extra source of stochasticity that may be important also in other signaling systems.
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Affiliation(s)
- Iain Hepburn
- Computational Neuroscience Unit, Okinawa Institute of Science and TechnologyOkinawa, Japan; Theoretical Neurobiology, University of AntwerpAntwerp, Belgium
| | - Anant Jain
- Computational Neuroscience Unit, Okinawa Institute of Science and TechnologyOkinawa, Japan; Department of Neurobiology, Northwestern UniversityEvanston, IL, USA
| | - Himanshu Gangal
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology Okinawa, Japan
| | - Yukio Yamamoto
- Center for Functional Connectomics, Korea Institute of Science and Technology Seoul, South Korea
| | - Keiko Tanaka-Yamamoto
- Center for Functional Connectomics, Korea Institute of Science and Technology Seoul, South Korea
| | - Erik De Schutter
- Computational Neuroscience Unit, Okinawa Institute of Science and TechnologyOkinawa, Japan; Theoretical Neurobiology, University of AntwerpAntwerp, Belgium
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7
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Stochastic Induction of Long-Term Potentiation and Long-Term Depression. Sci Rep 2016; 6:30899. [PMID: 27485552 PMCID: PMC4971485 DOI: 10.1038/srep30899] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/10/2016] [Indexed: 01/23/2023] Open
Abstract
Long-term depression (LTD) and long-term potentiation (LTP) of granule-Purkinje cell synapses are persistent synaptic alterations induced by high and low rises of the intracellular calcium ion concentration ([Ca2+]), respectively. The occurrence of LTD involves the activation of a positive feedback loop formed by protein kinase C, phospholipase A2, and the extracellular signal-regulated protein kinase pathway, and its expression comprises the reduction of the population of synaptic AMPA receptors. Recently, a stochastic computational model of these signalling processes demonstrated that, in single synapses, LTD is probabilistic and bistable. Here, we expanded this model to simulate LTP, which requires protein phosphatases and the increase in the population of synaptic AMPA receptors. Our results indicated that, in single synapses, while LTD is bistable, LTP is gradual. Ca2+ induced both processes stochastically. The magnitudes of the Ca2+ signals and the states of the signalling network regulated the likelihood of LTP and LTD and defined dynamic macroscopic Ca2+ thresholds for the synaptic modifications in populations of synapses according to an inverse Bienenstock, Cooper and Munro (BCM) rule or a sigmoidal function. In conclusion, our model presents a unifying mechanism that explains the macroscopic properties of LTP and LTD from their dynamics in single synapses.
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8
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Reinartz S, Finkernagel F, Adhikary T, Rohnalter V, Schumann T, Schober Y, Nockher WA, Nist A, Stiewe T, Jansen JM, Wagner U, Müller-Brüsselbach S, Müller R. A transcriptome-based global map of signaling pathways in the ovarian cancer microenvironment associated with clinical outcome. Genome Biol 2016; 17:108. [PMID: 27215396 PMCID: PMC4877997 DOI: 10.1186/s13059-016-0956-6] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 04/15/2016] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Soluble protein and lipid mediators play essential roles in the tumor environment, but their cellular origins, targets, and clinical relevance are only partially known. We have addressed this question for the most abundant cell types in human ovarian carcinoma ascites, namely tumor cells and tumor-associated macrophages. RESULTS Transcriptome-derived datasets were adjusted for errors caused by contaminating cell types by an algorithm using expression data derived from pure cell types as references. These data were utilized to construct a network of autocrine and paracrine signaling pathways comprising 358 common and 58 patient-specific signaling mediators and their receptors. RNA sequencing based predictions were confirmed for several proteins and lipid mediators. Published expression microarray results for 1018 patients were used to establish clinical correlations for a number of components with distinct cellular origins and target cells. Clear associations with early relapse were found for STAT3-inducing cytokines, specific components of WNT and fibroblast growth factor signaling, ephrin and semaphorin axon guidance molecules, and TGFβ/BMP-triggered pathways. An association with early relapse was also observed for secretory macrophage-derived phospholipase PLA2G7, its product arachidonic acid (AA) and signaling pathways controlled by the AA metabolites PGE2, PGI2, and LTB4. By contrast, the genes encoding norrin and its receptor frizzled 4, both selectively expressed by cancer cells and previously not linked to tumor suppression, show a striking association with a favorable clinical course. CONCLUSIONS We have established a signaling network operating in the ovarian cancer microenvironment with previously unidentified pathways and have defined clinically relevant components within this network.
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Affiliation(s)
- Silke Reinartz
- Clinic for Gynecology, Gynecological Oncology and Gynecological Endocrinology, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - Florian Finkernagel
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, Hans-Meerwein-Str. 3, Marburg, 35043, Germany
| | - Till Adhikary
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, Hans-Meerwein-Str. 3, Marburg, 35043, Germany
| | - Verena Rohnalter
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, Hans-Meerwein-Str. 3, Marburg, 35043, Germany
| | - Tim Schumann
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, Hans-Meerwein-Str. 3, Marburg, 35043, Germany
| | - Yvonne Schober
- Metabolomics Core Facility and Institute of Laboratory Medicine and Pathobiochemistry, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - W Andreas Nockher
- Metabolomics Core Facility and Institute of Laboratory Medicine and Pathobiochemistry, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - Andrea Nist
- Genomics Core Facility, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - Thorsten Stiewe
- Genomics Core Facility, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - Julia M Jansen
- Clinic for Gynecology, Gynecological Oncology and Gynecological Endocrinology, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - Uwe Wagner
- Clinic for Gynecology, Gynecological Oncology and Gynecological Endocrinology, Center for Tumor Biology and Immunology (ZTI), Philipps University, Marburg, Germany
| | - Sabine Müller-Brüsselbach
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, Hans-Meerwein-Str. 3, Marburg, 35043, Germany
| | - Rolf Müller
- Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology (ZTI), Philipps University, Hans-Meerwein-Str. 3, Marburg, 35043, Germany.
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9
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Pany S, Majhi A, Das J. Selective Modulation of Protein Kinase C α over Protein Kinase C ε by Curcumin and Its Derivatives in CHO-K1 Cells. Biochemistry 2016; 55:2135-43. [PMID: 26983836 DOI: 10.1021/acs.biochem.6b00057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Members of the protein kinase C (PKC) family of serine/threonine kinases regulate various cellular functions, including cell growth, differentiation, metabolism, and apoptosis. Modulation of isoform-selective activity of PKC by curcumin (1), the active constituent of Curcuma L., is poorly understood, and the literature data are inconsistent and obscure. The effect of curcumin (1) and its analogues, 4-[(2Z,6E)-3-hydroxy-7-(4-hydroxy-3-methoxyphenyl)-5-oxohepta-2,6-dien-1-yl]-2-methoxyphenyl oleate (2), (9Z,12Z)-4-[(2Z,6E)-3-hydroxy-7-(4-hydroxy-3-methoxyphenyl)-5-oxohepta-2,6-dien-1-yl]-2-methoxyphenyl octadeca-9,12-dienoate (3), (9Z,12Z,15Z)-4-[(2Z,6E)-3-hydroxy-7-(4-hydroxy-3-methoxyphenyl)-5-oxohepta-2,6-dien-1-yl]-2-methoxyphenyl octadeca-9,12,15-trienoate (4), and (1E,6E)-1-[4-(hexadecyloxy)-3-methoxyphenyl]-7-(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-dione (5), and didemethylcurcumin (6) on the membrane translocation of PKCα, a conventional PKC, and PKCε, a novel PKC, has been studied in CHO-K1 cells, in which these PKC isoforms are endogenously expressed. Translocation of PKC from the cytosol to the membrane was measured using immunoblotting and confocal microscopy. 1 and 6 inhibited the TPA-induced membrane translocation of PKCα but not of PKCε. Modification of the hydroxyl group of curcumin with a long aliphatic chain containing unsaturated double bonds in 2-4 completely abolished this inhibition property. Instead, 2-4 showed significant translocation of PKCα but not of PKCε to the membrane. No membrane translocation was observed with 1, 6, or the analogue 5 having a saturated long chain for either PKCα or PKCε. 1 and 6 inhibited TPA-induced activation of ERK1/2, and 2-4 activated it. ERK1/2 is the downstream readout of PKC. These results show that the hydroxyl group of curcumin is important for PKC activity and the curcumin template can be useful in developing isoform specific PKC modulators for regulating a particular disease state.
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Affiliation(s)
- Satyabrata Pany
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston , Houston, Texas 77204, United States
| | - Anjoy Majhi
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston , Houston, Texas 77204, United States
| | - Joydip Das
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston , Houston, Texas 77204, United States
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10
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Nadler A, Yushchenko DA, Müller R, Stein F, Feng S, Mulle C, Carta M, Schultz C. Exclusive photorelease of signalling lipids at the plasma membrane. Nat Commun 2015; 6:10056. [PMID: 26686736 PMCID: PMC4703838 DOI: 10.1038/ncomms10056] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 10/28/2015] [Indexed: 12/17/2022] Open
Abstract
Photoactivation of caged biomolecules has become a powerful approach to study cellular signalling events. Here we report a method for anchoring and uncaging biomolecules exclusively at the outer leaflet of the plasma membrane by employing a photocleavable, sulfonated coumarin derivative. The novel caging group allows quantifying the reaction progress and efficiency of uncaging reactions in a live-cell microscopy setup, thereby greatly improving the control of uncaging experiments. We synthesized arachidonic acid derivatives bearing the new negatively charged or a neutral, membrane-permeant coumarin caging group to locally induce signalling either at the plasma membrane or on internal membranes in β-cells and brain slices derived from C57B1/6 mice. Uncaging at the plasma membrane triggers a strong enhancement of calcium oscillations in β-cells and a pronounced potentiation of synaptic transmission while uncaging inside cells blocks calcium oscillations in β-cells and causes a more transient effect on neuronal transmission, respectively. The precise subcellular site of arachidonic acid release is therefore crucial for signalling outcome in two independent systems. Caged signalling intermediates are powerful cell biological tools, however it can be challenging to precisely control where activation occurs. Nadler et al. develop a caging group that specifically targets the plasma membrane, and demonstrate spatially controlled activation of arachidonic acid signalling.
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Affiliation(s)
- André Nadler
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Dmytro A Yushchenko
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany.,Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 16610 Prague 6, Czech Republic
| | - Rainer Müller
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Frank Stein
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Suihan Feng
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Christophe Mulle
- Institut Interdisciplinaire de Neurosciences, CNRS UMR 5297 Université Bordeaux 2, 146, rue Léo-Saignat, 33077 Bordeaux, France
| | - Mario Carta
- Institut Interdisciplinaire de Neurosciences, CNRS UMR 5297 Université Bordeaux 2, 146, rue Léo-Saignat, 33077 Bordeaux, France
| | - Carsten Schultz
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
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11
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Escribá PV, Busquets X, Inokuchi JI, Balogh G, Török Z, Horváth I, Harwood JL, Vígh L. Membrane lipid therapy: Modulation of the cell membrane composition and structure as a molecular base for drug discovery and new disease treatment. Prog Lipid Res 2015; 59:38-53. [PMID: 25969421 DOI: 10.1016/j.plipres.2015.04.003] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 04/10/2015] [Accepted: 04/29/2015] [Indexed: 01/17/2023]
Abstract
Nowadays we understand cell membranes not as a simple double lipid layer but as a collection of complex and dynamic protein-lipid structures and microdomains that serve as functional platforms for interacting signaling lipids and proteins. Membrane lipids and lipid structures participate directly as messengers or regulators of signal transduction. In addition, protein-lipid interactions participate in the localization of signaling protein partners to specific membrane microdomains. Thus, lipid alterations change cell signaling that are associated with a variety of diseases including cancer, obesity, neurodegenerative disorders, cardiovascular pathologies, etc. This article reviews the newly emerging field of membrane lipid therapy which involves the pharmacological regulation of membrane lipid composition and structure for the treatment of diseases. Membrane lipid therapy proposes the use of new molecules specifically designed to modify membrane lipid structures and microdomains as pharmaceutical disease-modifying agents by reversing the malfunction or altering the expression of disease-specific protein or lipid signal cascades. Here, we provide an in-depth analysis of this emerging field, especially its molecular bases and its relevance to the development of innovative therapeutic approaches.
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Affiliation(s)
- Pablo V Escribá
- Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Xavier Busquets
- Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Jin-ichi Inokuchi
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai, Japan
| | - Gábor Balogh
- Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary
| | - Zsolt Török
- Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary
| | - Ibolya Horváth
- Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, Wales, UK.
| | - László Vígh
- Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary.
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12
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Mangum LC, Borazjani A, Stokes JV, Matthews AT, Lee JH, Chambers JE, Ross MK. Organochlorine insecticides induce NADPH oxidase-dependent reactive oxygen species in human monocytic cells via phospholipase A2/arachidonic acid. Chem Res Toxicol 2015; 28:570-84. [PMID: 25633958 DOI: 10.1021/tx500323h] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Bioaccumulative organohalogen chemicals, such as organochlorine (OC) insecticides, have been increasingly associated with disease etiology; however, the mechanistic link between chemical exposure and diseases, such as atherosclerosis, cancer, and diabetes, is complex and poorly defined. Systemic oxidative stress stemming from OC exposure might play a vital role in the development of these pathologies. Monocytes are important surveillance cells of the innate immune system that respond to extracellular signals possessing danger-associated molecular patterns by synthesizing oxyradicals, such as superoxide, for the purpose of combating infectious pathogens. We hypothesized that OC chemicals can be toxic to monocytes because of an inappropriate elevation in superoxide-derived reactive oxygen species (ROS) capable of causing cellular oxidative damage. Reactive oxyradicals are generated in monocytes in large part by NADPH oxidase (Nox). The present study was conducted to examine the ability of two chlorinated cyclodiene compounds, trans-nonachlor and dieldrin, as well as p,p'-DDE, a chlorinated alicyclic metabolite of DDT, to stimulate Nox activity in a human monocytic cell line and to elucidate the mechanisms for this activation. Human THP-1 monocytes treated with either trans-nonachlor or dieldrin (0.1-10 μM in the culture medium) exhibited elevated levels of intracellular ROS, as evidenced by complementary methods, including flow cytometry analysis using the probe DCFH-DA and hydroethidine-based fluorometric and UPLC-MS assays. In addition, the induced reactive oxygen flux caused by trans-nonachlor was also observed in two other cell lines, murine J774 macrophages and human HL-60 cells. The central role of Nox in OC-mediated oxidative stress was demonstrated by the attenuated superoxide production in OC-exposed monocytes treated with the Nox inhibitors diphenyleneiodonium and VAS-2870. Moreover, monocytes challenged with OCs exhibited increased phospho-p47(phox) levels and enhanced p47(phox) membrane localization compared to that in vehicle-treated cells. p47(phox) is a cytosolic regulatory subunit of Nox, and its phosphorylation and translocation to the NOX2 catalytic subunit in membranes is a requisite step for Nox assembly and activation. Dieldrin and trans-nonachlor treatments of monocytes also resulted in marked increases in arachidonic acid (AA) and eicosanoid production, which could be abrogated by the phospholipase A2 (PLA2) inhibitor arachidonoyltrifluoromethyl ketone (ATK) but not by calcium-independent PLA2 inhibitor bromoenol lactone. This suggested that cytosolic PLA2 plays a crucial role in the induction of Nox activity by increasing the intracellular pool of AA that activates protein kinase C, which phosphorylates p47(phox). In addition, ATK also blocked OC-induced p47(phox) serine phosphorylation and attenuated ROS levels, which further supports the notion that the AA pool liberated by cytosolic PLA2 is responsible for Nox activation. Together, the results suggest that trans-nonachlor and dieldrin are capable of increasing intracellular superoxide levels via a Nox-dependent mechanism that relies on elevated intracellular AA levels. These findings are significant because chronic activation of monocytes by environmental toxicants might contribute to pathogenic oxidative stress and inflammation.
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Affiliation(s)
- Lee C Mangum
- Department of Basic Sciences, Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, P.O. Box 6100, Mississippi State, Mississippi 39762, United States
| | - Abdolsamad Borazjani
- Department of Basic Sciences, Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, P.O. Box 6100, Mississippi State, Mississippi 39762, United States
| | - John V Stokes
- Department of Basic Sciences, Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, P.O. Box 6100, Mississippi State, Mississippi 39762, United States
| | - Anberitha T Matthews
- Department of Basic Sciences, Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, P.O. Box 6100, Mississippi State, Mississippi 39762, United States
| | - Jung Hwa Lee
- Department of Basic Sciences, Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, P.O. Box 6100, Mississippi State, Mississippi 39762, United States
| | - Janice E Chambers
- Department of Basic Sciences, Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, P.O. Box 6100, Mississippi State, Mississippi 39762, United States
| | - Matthew K Ross
- Department of Basic Sciences, Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, P.O. Box 6100, Mississippi State, Mississippi 39762, United States
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13
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Balogh G, Péter M, Glatz A, Gombos I, Török Z, Horváth I, Harwood JL, Vígh L. Key role of lipids in heat stress management. FEBS Lett 2013; 587:1970-80. [PMID: 23684645 DOI: 10.1016/j.febslet.2013.05.016] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 05/06/2013] [Indexed: 12/15/2022]
Abstract
Heat stress is a common and, therefore, an important environmental impact on cells and organisms. While much attention has been paid to severe heat stress, moderate temperature elevations are also important. Here we discuss temperature sensing and how responses to heat stress are not necessarily dependent on denatured proteins. Indeed, it is clear that membrane lipids have a pivotal function. Details of membrane lipid changes and the associated production of signalling metabolites are described and suggestions made as to how the interconnected signalling network could be modified for helpful intervention in disease.
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Affiliation(s)
- Gábor Balogh
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, H-6701 Szeged, Hungary
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14
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Kawaguchi SY, Hirano T. Gating of long-term depression by Ca2+/calmodulin-dependent protein kinase II through enhanced cGMP signalling in cerebellar Purkinje cells. J Physiol 2013; 591:1707-30. [PMID: 23297306 DOI: 10.1113/jphysiol.2012.245787] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Long-term depression (LTD) at parallel fibre synapses on a cerebellar Purkinje cell has been regarded as a cellular basis for motor learning. Although Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) has been implicated in the LTD induction as an important Ca(2+)-sensing molecule, the underlying signalling mechanism remains unclear. Here, we attempted to explore the potential signalling pathway underlying the CaMKII involvement in LTD using a systems biology approach, combined with validation by electrophysiological and FRET imaging experiments on a rat cultured Purkinje cell. Model simulation predicted the following cascade as a candidate mechanism for the CaMKII contribution to LTD: CaMKII negatively regulates phosphodiesterase 1 (PDE1), subsequently facilitates the cGMP/protein kinase G (PKG) signalling pathway and down-regulates protein phosphatase 2A (PP-2A), thus supporting the LTD-inducing positive feedback loop consisting of mutual activation of protein kinase C (PKC) and mitogen-activated protein kinase (MAPK). This model suggestion was corroborated by whole-cell patch clamp recording experiments. In addition, FRET measurement of intracellular cGMP concentration revealed that CaMKII activation causes sustained increase of cGMP, supporting the signalling mechanism of LTD induction by CaMKII. Furthermore, we found that activation of the cGMP/PKG pathway by nitric oxide (NO) can support LTD induction without activation of CaMKII. Thus, this study clarified interaction between NO and Ca(2+)/CaMKII, two important factors required for LTD.
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Affiliation(s)
- Shin-ya Kawaguchi
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
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15
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De Schutter E. The importance of stochastic signaling processes in the induction of long-term synaptic plasticity. Neural Netw 2012; 47:3-10. [PMID: 23267752 DOI: 10.1016/j.neunet.2012.11.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 11/27/2012] [Accepted: 11/27/2012] [Indexed: 11/25/2022]
Abstract
A stochastic model of the signaling network responsible for the induction of long-term depression (LTD) at the parallel fiber to Purkinje cell synapse is described. The model includes a PKC-ERK-cPLA2 positive feedback loop and mechanisms of AMPA receptor trafficking. It was tuned to replicate calcium uncaging experiments that cause LTD. The ultrasensitive activation of ERK makes the signaling network activity bistable, causing either LTD or not. Therefore, in single synapses only two discrete stable states (LTD and non-LTD) can be expressed. The stochastic properties of the signaling network causes threshold dithering and probabilistic expression of LTD, which allows at the macroscopic level for many different and stable mean magnitudes of depression. When the volume of a single spine is simulated no thresholds for the calcium input signal are present. Such thresholds appear only when the volume of simulation is increased by a factor 100 or more and the model output is then bistable. Similarly, deterministic solutions of the same model show only bistable behavior. LTD induction requires activation of the PKC-ERK-cPLA2 positive feedback loop but this activity is not constant: the activities of ERK and of cPLA2 fluctuate strongly. This is much less the case for PKC which is more constantly activated and thereby promotes a stable output of the pathway.
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Affiliation(s)
- Erik De Schutter
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-Son, Okinawa 904-0495, Japan.
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16
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A stochastic signaling network mediates the probabilistic induction of cerebellar long-term depression. J Neurosci 2012; 32:9288-300. [PMID: 22764236 DOI: 10.1523/jneurosci.5976-11.2012] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Many cellular processes involve a small number of molecules and undergo stochastic fluctuations in their levels of activity. Cerebellar long-term depression (LTD) is a form of synaptic plasticity expressed as a reduction in the number of synaptic AMPA receptors (AMPARs) in Purkinje cells. We developed a stochastic model of the LTD signaling network, including a PKC-ERK-cPLA(2) positive feedback loop and mechanisms of AMPAR trafficking, and tuned the model to replicate calcium uncaging experiments. The signaling network activity in single synapses switches between two discrete stable states (LTD and non-LTD) in a probabilistic manner. The stochasticity of the signaling network causes threshold dithering and allows at the macroscopic level for many different and stable mean magnitudes of depression. The probability of LTD occurrence in a single spine is only modulated by the concentration and duration of the signal used to trigger it, and inputs with the same magnitude can give rise to two different responses; there is no threshold for the input signal. The stochasticity is intrinsic to the signaling network and not mostly dependent on noise in the calcium input signal, as has been suggested previously. The activities of the ultrasensitive ERK and of cPLA(2) undergo strong stochastic fluctuations. Conversely, PKC, which acts as a noise filter, is more constantly activated. Systematic variation of the biochemical population size demonstrates that threshold dithering and the absence of spontaneous LTD depend critically on the number of molecules in a spine, indicating constraints on spine size in Purkinje cells.
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17
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Tamassia N, Bazzoni F, Le Moigne V, Calzetti F, Masala C, Grisendi G, Bussmeyer U, Scutera S, De Gironcoli M, Costantini C, Musso T, Cassatella MA. IFN-β expression is directly activated in human neutrophils transfected with plasmid DNA and is further increased via TLR-4-mediated signaling. THE JOURNAL OF IMMUNOLOGY 2012; 189:1500-9. [PMID: 22730532 DOI: 10.4049/jimmunol.1102985] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Upon LPS binding, TLR4 activates a MyD88-dependent pathway leading to the transcriptional activation of proinflammatory genes, as well as a MyD88-independent/TRIF-dependent pathway, responsible for the transcriptional induction of IFN-β. Previous findings delineated that human neutrophils are unable to induce the transcription of IFN-β in response to TLR4 stimulation. Because neutrophils do not express protein kinase C ε, a molecule recently reported as essential for initiating the MyD88-independent/TRIF-dependent pathway, we optimized an electroporation method to transfect PKCε into neutrophils with very high efficiency. By doing so, a significant IFN-β mRNA expression was induced, in the absence of LPS stimulation, not only in PKCε-overexpressing neutrophils but also in cells transfected with a series of empty DNA plasmids; however, LPS further upregulated the IFN-β transcript levels in plasmid-transfected neutrophils, regardless of PKCε overexpression. Phosphoimmunoblotting studies, as well as chromatin immunoprecipitation assays targeting the IFN-β promoter, revealed that IFN-β mRNA induction occurred through the cooperative action of IRF3, activated by transfected DNA, and NF-κB, activated by LPS. Additional immunoblotting and coimmunoprecipitation studies revealed that neutrophils constitutively express various cytosolic DNA sensors, including IFN-inducible protein 16, leucine-rich repeat (in Flightless I) interacting protein-1, and DDX41, as well as that IFN-inducible protein 16 is the intracellular receptor recognizing transfected DNA. Consistently, infection of neutrophils with intracellular pathogens, such as Bartonella henselae, Listeria monocytogenes, Legionella pneumophila, or adenovirus type 5, promoted a marked induction of IFN-β mRNA expression. Taken together, these data raise questions about the role of PKCε in driving the MyD88-independent/TRIF-dependent response and indicate that human neutrophils are able to recognize and respond to microbial cytosolic DNA.
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Affiliation(s)
- Nicola Tamassia
- Section of General Pathology, Department of Pathology and Diagnostics, University of Verona, 37134 Verona, Italy
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18
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Chen L, Meng Q, Yu X, Li C, Zhang C, Cui C, Luo D. Possible mechanisms underlying the biphasic regulatory effects of arachidonic acid on Ca2+ signaling in HEK293 cells. Cell Signal 2012; 24:1565-72. [PMID: 22484156 DOI: 10.1016/j.cellsig.2012.03.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 03/21/2012] [Accepted: 03/21/2012] [Indexed: 12/01/2022]
Abstract
Arachidonic acid (AA), an endogenous lipid signal molecule released from membrane upon cell activation, modulates intracellular Ca(2+) ([Ca(2+)](i)) signaling positively and negatively. However, the mechanisms underlying the biphasic effects of AA are rather obscure. Using probes for measurements of [Ca(2+)](i) and fluidity of plasma membrane (PM)/endoplasmic reticulum (ER), immunostaining, immunoblotting and shRNA interference approaches, we found that AA at low concentration, 3 μM, reduced the PM fluidity by activating PKCα and PKCβII translocation to PM and also the ER fluidity directly. In accordance, 3 μM AA did not impact the basal [Ca(2+)](i) but significantly suppressed the thapsigargin-induced Ca(2+) release and Ca(2+) influx. Inhibition of PKC with Gö6983 or knockdown of PKCα or PKCβ using shRNA significantly attenuated the inhibitory effects of 3 μM AA on PM fluidity and agonist-induced Ca(2+) signal. However, AA at high concentration, 30 μM, caused robust release and entry of Ca(2+) accompanied by a facilitated PM fluidity but decreased ER fluidity and dramatic PKCβI and PKCβII redistribution in the ER. Compared with ursodeoxycholate acid, a membrane stabilizing agent that only inhibited the 30 μM AA-induced Ca(2+) influx by 45%, Gd(3+) at concentration of 10 μM could completely abolish both release and entry of Ca(2+) induced by AA, suggesting that the potentiated PM fluidity is not the only reason for AA eliciting Ca(2+) signal. Therefore, the study herein demonstrates that a lowered PM fluidity by PKC activation and a direct ER stabilization contribute significantly for AA downregulation of [Ca(2+)](i) response, while Gd(3+)-sensitive 'pores' in PM/ER play an important role in AA-induced Ca(2+) signal in HEK293 cells.
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Affiliation(s)
- Lihong Chen
- Department of Pharmacology, School of Chemical Biology & Pharmaceutical Sciences, Capital Medical University, Beijing, PR China
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19
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Juan YS, Chuang SM, Long CY, Lin RJ, Liu KM, Wu WJ, Huang CH. Protein kinase C inhibitor prevents renal apoptotic and fibrotic changes in response to partial ureteric obstruction. BJU Int 2011; 110:283-92. [DOI: 10.1111/j.1464-410x.2011.10805.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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20
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Arsenault R, Griebel P, Napper S. Peptide arrays for kinome analysis: New opportunities and remaining challenges. Proteomics 2011; 11:4595-609. [DOI: 10.1002/pmic.201100296] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 09/28/2011] [Accepted: 10/04/2011] [Indexed: 01/08/2023]
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21
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Bender KJ, Ford CP, Trussell LO. Dopaminergic modulation of axon initial segment calcium channels regulates action potential initiation. Neuron 2010; 68:500-11. [PMID: 21040850 DOI: 10.1016/j.neuron.2010.09.026] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2010] [Indexed: 11/18/2022]
Abstract
Action potentials initiate in the axon initial segment (AIS), a specialized compartment enriched with Na(+) and K(+) channels. Recently, we found that T- and R-type Ca(2+) channels are concentrated in the AIS, where they contribute to local subthreshold membrane depolarization and thereby influence action potential initiation. While periods of high-frequency activity can alter availability of AIS voltage-gated channels, mechanisms for long-term modulation of AIS channel function remain unknown. Here, we examined the regulatory pathways that control AIS Ca(2+) channel activity in brainstem interneurons. T-type Ca(2+) channels were downregulated by dopamine receptor activation acting via protein kinase C, which in turn reduced neuronal output. These effects occurred without altering AIS Na(+) or somatodendritic T-type channel activity and could be mediated by endogenous dopamine sources present in the auditory brainstem. This pathway represents a new mechanism to inhibit neurons by specifically regulating Ca(2+) channels directly involved in action potential initiation.
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Affiliation(s)
- Kevin J Bender
- Oregon Hearing Research Center, Oregon Health and Science University, Portland, OR 97239, USA.
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22
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Niger C, Hebert C, Stains JP. Interaction of connexin43 and protein kinase C-delta during FGF2 signaling. BMC BIOCHEMISTRY 2010; 11:14. [PMID: 20338032 PMCID: PMC2855512 DOI: 10.1186/1471-2091-11-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Accepted: 03/25/2010] [Indexed: 01/07/2023]
Abstract
Background We have recently demonstrated that modulation of the gap junction protein, connexin43, can affect the response of osteoblasts to fibroblast growth factor 2 in a protein kinase C-delta-dependent manner. Others have shown that the C-terminal tail of connexin43 serves as a docking platform for signaling complexes. It is unknown whether protein kinase C-delta can physically interact with connexin43. Results In the present study, we investigate by immunofluorescent co-detection and biochemical examination the interaction between Cx43 and protein kinase C-delta. We establish that protein kinase C-delta physically interacts with connexin43 during fibroblast growth factor 2 signaling, and that protein kinase C delta preferentially co-precipitates phosphorylated connexin43. Further, we show by pull down assay that protein kinase C-delta associates with the C-terminal tail of connexin43. Conclusions Connexin43 can serve as a direct docking platform for the recruitment of protein kinase C-delta in order to affect fibroblast growth factor 2 signaling in osteoblasts. These data expand the list of signal molecules that assemble on the connexin43 C-terminal tail and provide a critical context to understand how gap junctions modify signal transduction cascades in order to impact cell function.
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Affiliation(s)
- Corinne Niger
- Department of Orthopaedics, University of Maryland, School of Medicine, Baltimore, MD, USA
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23
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Eglen RM, Reisine T. Human kinome drug discovery and the emerging importance of atypical allosteric inhibitors. Expert Opin Drug Discov 2010; 5:277-90. [PMID: 22823023 DOI: 10.1517/17460441003636820] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
IMPORTANCE OF THE FIELD Protein kinases are important targets for drug discovery because they possess critical roles in many human diseases. Several protein kinase inhibitors have entered clinical development with others having already been approved for treating a host of diseases. However, many kinase inhibitors suffer from non-selectivity because they interact with the ATP binding region which has similar structures amongst the protein kinases and this non-selectivity sometimes can cause side effects. As a consequence, there is much interest in developing drugs that inhibit kinases through non-classical mechanisms with the hope of avoiding the side effects of previous kinase drugs. AREAS COVERED IN THIS REVIEW This review covers emerging information on kinase biology and discusses new approaches to design selective inhibitors that do not compete with ATP. WHAT THE READER WILL GAIN The reader will gain a better understanding of the importance of the field of allosteric inhibitor drug discovery and how this has required the adoption of a new generation of high-throughput screening techniques. TAKE HOME MESSAGE Discovery and development of allosteric modulators will result in a family of novel kinase therapies with greater selectivity and more varied ways to control activity of disease causing kinase targets.
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Affiliation(s)
- Richard M Eglen
- Bio-discovery, PerkinElmer Life and Analytical Sciences, 940 Winter St., Waltham, MA, USA +1 781 663 5599 ; +1 781 663 5984 ;
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Signorello MG, Segantin A, Leoncini G. The arachidonic acid effect on platelet nitric oxide level. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:1084-92. [PMID: 19615463 DOI: 10.1016/j.bbalip.2009.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 06/26/2009] [Accepted: 07/03/2009] [Indexed: 10/20/2022]
Abstract
Arachidonic acid can act as a second messenger regulating many cellular processes among which is nitric oxide (NO) formation. The aim of the present study was to investigate the molecular mechanisms involved in the arachidonic acid effect on platelet NO level. Thus NO, cGMP and superoxide anion level, the phosphorylation status of nitric oxide synthase, the protein kinase C (PKC), and NADPH oxidase activation were measured. Arachidonic acid dose-dependently reduced NO and cGMP level. The thromboxane A(2) mimetic U46619 behaved in a similar way. The arachidonic acid or U46619 effect on NO concentration was abolished by the inhibitor of the thromboxane A(2) receptor SQ29548 and partially reversed by the PKC inhibitor GF109203X or by the phospholipase C pathway inhibitor U73122. Moreover, it was shown that arachidonic acid activated PKC and decreased nitric oxide synthase (eNOS) activities. The phosphorylation of the inhibiting eNOSthr495 residue mediated by PKC was increased by arachidonic acid, while no changes at the activating ser1177 residue were shown. Finally, arachidonic acid induced NADPH oxidase activation and superoxide anion formation. These effects were greatly reduced by GF109203X, U73122, and apocynin. Likely arachidonic acid reducing NO bioavailability through all these mechanisms could potentiate its platelet aggregating power.
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Affiliation(s)
- Maria Grazia Signorello
- Department of Experimental Medicine, Biochemistry Section, University of Genoa, Viale Benedetto XV 1, 16132 Genova, Italy
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25
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Lima F, Niger C, Hebert C, Stains JP. Connexin43 potentiates osteoblast responsiveness to fibroblast growth factor 2 via a protein kinase C-delta/Runx2-dependent mechanism. Mol Biol Cell 2009; 20:2697-708. [PMID: 19339281 PMCID: PMC2688549 DOI: 10.1091/mbc.e08-10-1079] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 03/20/2009] [Accepted: 03/24/2009] [Indexed: 12/13/2022] Open
Abstract
In this study, we examine the role of the gap junction protein, connexin43 (Cx43), in the transcriptional response of osteocalcin to fibroblast growth factor 2 (FGF2) in MC3T3 osteoblasts. By luciferase reporter assays, we identify that the osteocalcin transcriptional response to FGF2 is markedly increased by overexpression of Cx43, an effect that is mediated by Runx2 via its OSE2 cognate element, but not by a previously identified connexin-responsive Sp1/Sp3-binding element. Furthermore, disruption of Cx43 function with Cx43 siRNAs or overexpression of connexin45 markedly attenuates the response to FGF2. Inhibition of protein kinase C delta (PKCdelta) with rottlerin or siRNA-mediated knockdown abrogates the osteocalcin response to FGF2. Additionally, we show that upon treatment with FGF2, PKCdelta translocates to the nucleus, PKCdelta and Runx2 are phosphorylated and these events are enhanced by Cx43 overexpression, suggesting that the degree of activation is enhanced by increased Cx43 levels. Indeed, chromatin immunoprecipitations of the osteocalcin proximal promoter with antibodies against Runx2 demonstrate that the recruitment of Runx2 to the osteocalcin promoter in response to FGF2 treatment is dramatically enhanced by Cx43 overexpression. Thus, Cx43 plays a critical role in regulating the ability of osteoblasts to respond to FGF2 by impacting PKCdelta and Runx2 function.
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Affiliation(s)
- Florence Lima
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Corinne Niger
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Carla Hebert
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Joseph P. Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201
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26
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van Rossum DB, Patterson RL. PKC and PLA2: probing the complexities of the calcium network. Cell Calcium 2009; 45:535-45. [PMID: 19345415 DOI: 10.1016/j.ceca.2009.02.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 02/24/2009] [Accepted: 02/26/2009] [Indexed: 11/15/2022]
Abstract
Lipid signaling and phosphorylation cascades are fundamental to calcium signaling networks. In this review, we will discuss the recent laboratory findings for the phospholipase A(2) (PLA(2))/protein kinase C (PKC) pathway within cellular calcium networks. The complexity and connectivity of these ubiquitous cellular signals make interpretation of experimental results extremely challenging. We present here computational methods which have been developed to conquer such complex data, and how they can be used to make models capable of accurately predicting cellular responses within multiple calcium signaling pathways. We propose that information obtained from network analysis and computational techniques provides a rich source of knowledge which can be directly translated to the laboratory benchtop.
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Affiliation(s)
- Damian B van Rossum
- Department of Biology, The Pennsylvania State University, PA, United States.
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Eglen RM, Reisine T. The Current Status of Drug Discovery Against the Human Kinome. Assay Drug Dev Technol 2009; 7:22-43. [DOI: 10.1089/adt.2008.164] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Richard M. Eglen
- Bio-discovery, PerkinElmer Life and Analytical Sciences, Waltham, Massachusetts
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28
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Mashimo M, Hirabayashi T, Murayama T, Shimizu T. Cytosolic PLA2(alpha) activation in Purkinje neurons and its role in AMPA-receptor trafficking. J Cell Sci 2008; 121:3015-24. [PMID: 18713832 DOI: 10.1242/jcs.032987] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cytosolic phospholipase A(2)alpha (cPLA(2)alpha) selectively releases arachidonic acid from membrane phospholipids and has been proposed to be involved in the induction of long-term depression (LTD), a form of synaptic plasticity in the cerebellum. This enzyme requires two events for its full activation: Ca(2+)-dependent translocation from the cytosol to organelle membranes in order to access phospholipids as substrates, and phosphorylation by several kinases. However, the subcellular distribution and activation of cPLA(2)alpha in Purkinje cells and the role of arachidonic acid in cerebellar LTD have not been fully elucidated. In cultured Purkinje cells, stimulation of AMPA receptors, but not metabotropic glutamate receptors, triggered translocation of cPLA(2)alpha to the somatic and dendritic Golgi compartments. This translocation required Ca(2+) influx through P-type Ca(2+) channels. AMPA plus PMA, a chemical method for inducing LTD, released arachidonic acid via phosphorylation of cPLA(2)alpha. AMPA plus PMA induced a decrease in surface GluR2 for more than 2 hours. Interestingly, this reduction was occluded by a cPLA(2)alpha-specific inhibitor. Furthermore, PMA plus arachidonic acid caused the prolonged internalization of GluR2 without activating AMPA receptors. These results suggest that cPLA(2)alpha regulates the persistent decrease in the expression of AMPA receptors, underscoring the role of cPLA(2)alpha in cerebellar LTD.
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Affiliation(s)
- Masato Mashimo
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University, Chuo-ku, Chiba 260-8675, Japan
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29
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Wooten RE, Willingham MC, Daniel LW, Leslie CC, Rogers LC, Sergeant S, O'Flaherty JT. Novel translocation responses of cytosolic phospholipase A2alpha fluorescent proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1544-50. [PMID: 18406359 DOI: 10.1016/j.bbamcr.2008.03.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 03/04/2008] [Accepted: 03/05/2008] [Indexed: 12/13/2022]
Abstract
Cytosolic phospholipase A2 (cPLA2)alpha responds to the rise in cytosolic Ca2+ ([Ca2+]i) attending cell stimulation by moving to intracellular membranes, releasing arachidonic acid (AA) from these membranes, and thereby initiating the synthesis of various lipid mediators. Under some conditions, however, cPLA2alpha translocation occurs without any corresponding changes in [Ca2+]i. The signal for such responses has not been identified. Using confocal microscopy to track fluorescent proteins fused to cPLA2alpha or cPLA2alpha's C2 domain, we find that AA mimics Ca2+ ionophores in stimulating cPLA(2)alpha translocations to the perinuclear ER and to a novel site, the lipid body. Unlike the ionophores, AA acted independently of [Ca2+](i) rises and did not translocate the proteins to the Golgi. AA's action did not involve its metabolism to eicosanoids or acylation into cellular lipids. Receptor agonists also stimulated translocations targeting lipid bodies. We propose that AA is a signal for Ca2+-independent cPLA2alpha translocation and that lipid bodies are common targets of cPLA2alpha and contributors to stimulus-induced lipid mediator synthesis.
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Affiliation(s)
- Rhonda E Wooten
- Department of Internal Medicine, Section on Infectious Diseases, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157, USA
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Martins de Lima T, Gorjão R, Hatanaka E, Cury-Boaventura MF, Portioli Silva EP, Procopio J, Curi R. Mechanisms by which fatty acids regulate leucocyte function. Clin Sci (Lond) 2007; 113:65-77. [PMID: 17555405 DOI: 10.1042/cs20070006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Fatty acids (FAs) have been shown to alter leucocyte function and thus to modulate inflammatory and immune responses. In this review, the effects of FAs on several aspects of lymphocyte, neutrophil and macrophage function are discussed. The mechanisms by which FAs modulate the production of lipid mediators, activity of intracellular signalling pathways, activity of lipid-raft-associated proteins, binding to TLRs (Toll-like receptors), control of gene expression, activation of transcription factors, induction of cell death and production of reactive oxygen and nitrogen species are described in this review. The rationale for the use of specific FAs to treat patients with impaired immune function is explained. Substantial improvement in the therapeutic usage of FAs or FA derivatives may be possible based on an improvement in the understanding of the precise molecular mechanisms of action with respect to the different leucocyte types and outcome with respect to the inflammatory responses.
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Affiliation(s)
- Thais Martins de Lima
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
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Morgan D, Cherny VV, Finnegan A, Bollinger J, Gelb MH, DeCoursey TE. Sustained activation of proton channels and NADPH oxidase in human eosinophils and murine granulocytes requires PKC but not cPLA2 alpha activity. J Physiol 2006; 579:327-44. [PMID: 17185330 PMCID: PMC2075394 DOI: 10.1113/jphysiol.2006.124248] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The prevailing hypothesis that a signalling pathway involving cPLA(2)alpha is required to enhance the gating of the voltage-gated proton channel associated with NADPH oxidase was tested in human eosinophils and murine granulocytes. This hypothesis invokes arachidonic acid (AA) liberated by cPLA(2)alpha as a final activator of proton channels. In human eosinophils studied in the perforated-patch configuration, phorbol myristate acetate (PMA) stimulation elicited NADPH oxidase-generated electron current (I(e)) and enhanced proton channel gating identically in the presence or absence of three specific cPLA(2)alpha inhibitors, Wyeth-1, pyrrolidine-2 and AACOCF(3) (arachidonyl trifluoromethyl ketone). In contrast, PKC inhibitors GFX (GF109203X) or staurosporine prevented the activation of either proton channels or NADPH oxidase. PKC inhibition during the respiratory burst reversed the activation of both molecules, suggesting that ongoing phosphorylation is required. This effect of GFX was inhibited by okadaic acid, implicating phosphatases in proton channel deactivation. Proton channel activation by AA was partially reversed by GFX or staurosporine, indicating that AA effects are due in part to activation of PKC. In granulocytes from mice with the cPLA(2)alpha gene disrupted (knockout mice), PMA or fMetLeuPhe activated NADPH oxidase and proton channels in a manner indistinguishable from the responses of control cells. Thus, cPLA(2)alpha is not essential to activate the proton conductance or for a normal respiratory burst. Instead, phosphorylation of the proton channel or an activating molecule converts the channel to its activated gating mode. The existing paradigm for regulation of the concerted activity of proton channels and NADPH oxidase must be revised.
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Affiliation(s)
- Deri Morgan
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, 1750 West Harrison, Chicago, IL 60612 USA
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López-Nicolás R, López-Andreo MJ, Marín-Vicente C, Gómez-Fernández JC, Corbalán-García S. Molecular Mechanisms of PKCα localization and Activation by Arachidonic Acid. The C2 Domain also Plays a Role. J Mol Biol 2006; 357:1105-20. [PMID: 16476439 DOI: 10.1016/j.jmb.2006.01.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Revised: 01/04/2006] [Accepted: 01/06/2006] [Indexed: 10/25/2022]
Abstract
Arachidonic acid, one of the major unsaturated fatty acids released during cell stimulation, participates in the signaling necessary for activation of different enzymes, including protein kinase C (PKC). Here, we demonstrate that arachidonic acid is a direct activator of PKCalpha, but needs the cooperation of Ca(2+) to exert its function. By using several mutants of the C2 and C1 domains, we were able to determine the molecular mechanism of this activation. More specifically, site-directed mutagenesis in key residues found in the C2 domain showed that the Ca(2+)-binding region was essential for the arachidonic acid-dependent localization and activation of PKCalpha. However, the lysine-rich cluster, also located in the C2 domain, played no relevant role in either the membrane localization or activation of the enzyme. Moreover, site-directed mutagenesis in key residues placed in the C1A and C1B subdomains, which are responsible for the diacylglycerol/phorbil ester interaction, demonstrated that the C1A subdomain was involved in the membrane localization and activation mechanism. Taken together, these data suggest a very precise mechanism for PKCalpha activation by arachidonic acid, involving a sequential model of activation in which an increase in intracytosolic Ca(2+) leads to the interaction of arachidonic acid with the Ca(2+)-binding region; only after this step, does the C1A subdomain interact with arachidonic acid, leading to full activation of the enzyme.
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Affiliation(s)
- Rubén López-Nicolás
- Departemento. de Bioquímica y Biología Molecular (A), Facultad de Veterinaria, Universidad de Murcia, Apdo 4021, E-30100 Murcia, Spain
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Kim C, Dinauer MC. Impaired NADPH oxidase activity in Rac2-deficient murine neutrophils does not result from defective translocation of p47phox and p67phox and can be rescued by exogenous arachidonic acid. J Leukoc Biol 2006; 79:223-34. [PMID: 16275890 DOI: 10.1189/jlb.0705371] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Rac2 is a hematopoietic-specific Rho-GTPase that plays a stimulus-specific role in regulating reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation and other functional responses in neutrophils. In this study, rac2-/- neutrophils were shown to have significantly decreased NADPH oxidase activity and actin remodeling in response to exogenous arachidonic acid (AA), as previously observed for phorbol 12-myristate 13-acetate (PMA) or formyl-Met-Leu-Phe (fMLP) as agonists. PMA-, fMLP-, or AA-induced translocation of p47phox and p67phox to the plasma membrane was not impaired in rac2-/- neutrophils. Combined stimulation of rac2-/- neutrophils with exogenous AA and PMA had a synergistic effect on NADPH oxidase activity, and superoxide production increased to a level that was at least as high as wild-type cells and had no effect on fMLP-elicited enzyme activity. Membrane translocation of p47phox and p67phox as well as Rac1 activation was not increased further by combined PMA and AA stimulation. Inhibitor studies were consistent with important roles for phorbol ester-activated protein kinase C (PKC) isoforms and an atypical isoform, PKCzeta, in superoxide production by wild-type and rac2-/- neutrophils stimulated with AA and PMA. In addition, PMA-stimulated release of AA and cytoplasmic phospholipase A2 expression in rac2-/- neutrophils were similar to wild-type, suggesting that deficient AA production by PMA-stimulated rac2-/- neutrophils does not explain the effect of exogenous AA on oxidase activity. Although not required for translocation of p47phox and p67phox, Rac2 is necessary for optimal activity of the assembled oxidase complex, an effect that can be replaced by exogenous AA, which may act directly or via an exogenous AA-induced mediator.
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Affiliation(s)
- Chaekyun Kim
- Herman B. Wells Center for Pediatric Research, Department of Pediatrics (Hematology/Oncology), James Whitcomb Riley Hospital for Children, Indiana University Medical Center, Indianapolis, IN, USA
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Serezani CHC, Aronoff DM, Jancar S, Peters-Golden M. Leukotriene B4mediates p47phox phosphorylation and membrane translocation in polyunsaturated fatty acid-stimulated neutrophils. J Leukoc Biol 2005; 78:976-84. [PMID: 16006535 DOI: 10.1189/jlb.1004587] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Polyunsaturated fatty acids (PUFAs) and leukotriene B(4) (LTB(4)) are involved in many inflammatory and physiological conditions. The role of arachidonic acid (AA) and linoleic acid (LA) in promoting the assembly of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits is well known, but the involvement of LTB(4) and other 5-lipoxygenase (5-LO) pathway metabolites of AA in hydrogen peroxide (H(2)O(2)) production by PUFA-stimulated polymorphonuclear leukocytes (PMNs) has not been investigated. We examined this question by determining H(2)O(2) production as well as phosphorylation and membrane translocation of the p47phox subunit of NADPH oxidase. Elicited peritoneal PMNs from rats and from 5-LO-deficient or wild-type mice were pretreated with or without inhibitors of LT biosynthesis and antagonists of the receptors for LTB(4) and cysteinyl LTs for 20 min before stimulation with AA (at 5 and 20 microM) or LA (at 20 microM). PUFAs elicited H(2)O(2) production in a dose-dependent manner, and pharmacologic or genetic inhibition of LT synthesis decreased H(2)O(2) production by approximately 40% when compared with untreated controls. LTB(4) was the moiety responsible for H(2)O(2) production, as revealed by studies using receptor antagonists and its exogenous addition. LTB(4) itself also promoted p47phox phosphorylation and translocation. These results identify a heretofore unrecognized role for activation of 5-LO and subsequent production of LTB(4) in stimulation of PMN NADPH oxidase activation by PUFAs.
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Affiliation(s)
- Carlos H C Serezani
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, medical School, University of Michigan Health System, 6301 MSRB III, Box 0642, 1150 W. Medical Center Drive, Ann Arbor, MI 48109-0642, USA
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Guidarelli A, Cerioni L, Tommasini I, Brüne B, Cantoni O. A downstream role for protein kinase Calpha in the cytosolic phospholipase A2-dependent protective signalling mediated by peroxynitrite in U937 cells. Biochem Pharmacol 2005; 69:1275-86. [PMID: 15794949 DOI: 10.1016/j.bcp.2005.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2005] [Revised: 02/08/2005] [Accepted: 02/08/2005] [Indexed: 11/21/2022]
Abstract
Exposure to an otherwise non-toxic concentration of peroxynitrite (ONOO-) promotes toxicity in U937 cells supplemented with pharmacological inhibitors of protein kinase C (PKC). This effect is not associated with enhanced formation of H2O2 and is in fact causally linked to inhibition of the cytoprotective signalling driven by endogenous arachidonic acid (AA). The outcome of various approaches using PKC or phospholipase A2 inhibitors, cytosolic phospholipase A2 or PKCalpha antisense-oligonucleotide-transfected cells and supplementation with exogenous AA or tetradecanoylphorbol acetate, as well as PKC down-regulated cells, indicated that ONOO- promotes AA-dependent cytosol to membrane translocation of PKCalpha, an event critical for the cytoprotective signalling under investigation. Evidence for a similar mechanism regulating survival of human monocytes exposed to ONOO- is also presented. These results, along with our previous work on this topic, contribute to the definition of the mechanism whereby monocytes survive to ONOO- in inflamed tissues.
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Affiliation(s)
- Andrea Guidarelli
- Istituto di Farmacologia e Farmacognosia, Università degli Studi di Urbino "Carlo Bo", Via S. Chiara, 27-61029 Urbino (PU), Italy
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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.
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Affiliation(s)
- Carlos H C Serezani
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109-0642, USA
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Tommasini I, Sestili P, Guidarelli A, Cantoni O. Hydrogen peroxide generated at the level of mitochondria in response to peroxynitrite promotes U937 cell death via inhibition of the cytoprotective signalling mediated by cytosolic phospholipase A2. Cell Death Differ 2005; 11:974-84. [PMID: 15153939 DOI: 10.1038/sj.cdd.4401419] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We have studied the relationships existing between delayed formation of H2O2 and activation of cytosolic phospholipase A2 (cPLA2), events respectively promoting toxicity or survival in U937 cells exposed to peroxynitrite. The outcome of an array of different approaches using phospholipase A2 inhibitors, or cPLA2 antisense oligonucleotides, as well as specific respiratory chain inhibitors and respiration-deficient cells led to the demonstration that H2O2 does not mediate toxicity by producing direct molecular damage. Rather, the effects of H2O2 were found to be upstream to the arachidonic acid (AA)-mediated cytoprotective signalling and in fact causally linked to inhibition of cPLA2. Thus, it appears that U937 cells exposed to nontoxic concentrations of peroxynitrite are nevertheless committed to death, which however is normally prevented by the activation of parallel pathways resulting in cPLA2-dependent release of AA. A rapid necrotic response, however, takes place when high concentrations of peroxynitrite promote formation of H2O2 at levels impairing the cPLA2 cytoprotective signalling.
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Affiliation(s)
- I Tommasini
- Istituto di Farmacologia e Farmacognosia, Università degli Studi di Urbino Carlo Bo, Via S Chiara, 27-61029 Urbino (PU), Italy
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Morishige JI, Takai Y, Hirano K, Tanaka T, Satouchi K. Production and protein kinase C activation of diacylglycerols containing polymethylene-interrupted PUFA. Lipids 2005; 40:155-62. [PMID: 15884763 DOI: 10.1007/s11745-005-1370-8] [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: 11/24/2022]
Abstract
Sciadonic acid (20:3, delta-5c,11 c,14c) is a polymethylene-interrupted PUFA (PMI-PUFA) that is present in conifer seeds and known to be incorporated into animal cells and to accumulate in membrane PI as a substitute for arachidonate. In this study, we investigated whether PI having sciadonate could serve as source of DAG that could activate protein kinase C (PKC). When Swiss 3T3 cells cultured with sciadonic acid were stimulated with 100 nM of bombesin, 1-stearoyl-2-sciadonoyl-glycerol (G) and 1-stearoyl-2-arachidonoyl-G were produced. The net increments of these two molecular species of DAG reflected the levels of the two molecular species in the PI in the cells. When cells cultured with juniperonic acid (20:4, delta-5c,11c,14c,17c) were stimulated, 1-stearoyl-2-juniperonoyl-G was produced in proportion to the level of this molecular species in PI in the cells. We also examined PKC activation by synthetic DAG using a partially purified PKC fraction from rat brain and found that both 1-stearoyl-2-sciadonoyl-G and 1-stearoyl-2-juniperonoyl-G could activate PKC comparably to 1 -stearoyl-2-arachidonoyl-G. These results indicate that 1-stearoyl-PI having these C20 PMI-PUFA residues can serve as sources of potential signaling molecules.
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Affiliation(s)
- Jun-ichi Morishige
- Department of Applied Biological Science, Fukuyama University, Fukuyama 729-0292, Japan
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Polosukhina D, Singaravelu K, Padanilam BJ. Activation of protein kinase C isozymes protects LLCPK1 cells from H2O2 induced necrotic cell death. Am J Nephrol 2003; 23:380-9. [PMID: 14551462 DOI: 10.1159/000073984] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2003] [Accepted: 08/29/2003] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS We have previously reported that ischemia/reperfusion injury (IRI) to the kidney leads to induced expression of RACK1 and changes in the level of expression and subcellular distribution of PKC isozymes alpha, betaII and zeta. In order to further define the role of PKC isozymes in IRI we investigated the effect of activation or inhibition of the isozymes on cytotoxicity mediated by H(2)O(2) in LLCPK(1) cells. METHODS Cytotoxicity was analyzed by Trypan blue assay and LDH release assay. Translocation of PKC isozymes postinjury in LLCPK1 cells was analyzed by immunostaining and Western blot analysis. RESULTS Western blot analysis showed that the expression of PKC-alpha was up-regulated in a triphasic pattern with the initial induction within the first 10 min of injury followed by higher levels of expression at 2 and 24 h postinjury. The expression of PKC-zeta was highly induced within the first 15 min of injury but its expression was down-regulated to that of normal levels by 30 min postinjury. Immunocytochemistry showed that both PKC-alpha and PKC-zeta translocated to the nucleus and perinuclear region during H(2)O(2) treatment. Following injury, PKC-alpha expression was localized to the nuclear membrane at earlier time points but a translocation to the nucleus occurred at later time points. PKC-zeta translocated to nucleus at 30 minutes post injury and relocated back to the nuclear membrane at later time points. CONCLUSION These data suggest that activation of PKC-alpha and PKC-zeta is involved in the H(2)O(2) induced injury of LLCPK1 cells.
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Affiliation(s)
- Dina Polosukhina
- Department of Physiology and Biophysics, University of Nebraska Medical Center, Omaha, Nebr. 68198-4575 USA.
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Platten M, Eitel K, Wischhusen J, Dichgans J, Weller M. Involvement of protein kinase Cδ and extracellular signal-regulated kinase-2 in the suppression of microglial inducible nitric oxide synthase expression by N-[3,4-dimethoxycinnamoyl]-anthranilic acid (tranilast). Biochem Pharmacol 2003; 66:1263-70. [PMID: 14505805 DOI: 10.1016/s0006-2952(03)00449-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Excess nitric oxide (NO) in the brain released by microglial cells contributes to neuronal damage in various pathologies of the central nervous system (CNS) including neurodegenerative diseases and multiple sclerosis. N-[3,4-Dimethoxycinnamoyl]-anthranilic acid (tranilast, TNL) is an anti-allergic compound which suppresses the activation of monocytes. We show that inducible nitric oxide synthase (iNOS) mRNA and protein expression and the release of NO from N9 microglial cells stimulated with the bacterial endotoxin lipopolysaccharide (LPS) are inhibited when the cells are exposed to TNL. TNL fails to modulate LPS-stimulated nuclear factor-kappaB (NF-kappaB) reporter gene activity and phosphorylation of inhibitory kappaB (IkappaB), indicating that NF-kappaB is not involved in the TNL-mediated suppression of LPS-induced iNOS expression. Moreover, TNL inhibits LPS-induced phosphorylation of extracellular signal-regulated kinase 2 (ERK-2). Finally, TNL abolishes translocation of protein kinase Cdelta (PKCdelta) to the nucleus and suppresses the phosphorylation of the PKCdelta substrate, myristoylated alanin-rich C kinase substrate (MARCKS). We conclude that the anti-allergic compound TNL suppresses microglial iNOS induction by LPS via inhibition of a signalling pathway involving PKCdelta and ERK-2.
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Affiliation(s)
- Michael Platten
- Department of Neurology, University of Tübingen, 72076 Tübingen, Germany
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Walch L, Norel X, Gascard JP, Brink C. Arachidonic acid inhibits cysteinyl-leukotriene receptor activation in human pulmonary vessels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 525:75-9. [PMID: 12751740 DOI: 10.1007/978-1-4419-9194-2_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
The mechanism of action of feG, an anti-inflammatory peptide, was explored using data mining, molecular modeling, and enzymatic techniques. The molecular coordinates of protein kinase A (PKA) were used to create six virtual isoforms of protein kinase C (PKCalpha, betaI, betaII, delta, iota, and zeta). With in silico techniques a binding site for feG was identified on PKCbetaI that correlated significantly with a biological activity, the inhibition of intestinal anaphylaxis. Since feG selectively increased the binding of a PKCbetaI antibody, it is proposed that this peptide inhibits the reassociation of the hydrophobic tail of PKCbetaI with its binding site and prevents the enzyme from assuming an inactive conformation.
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Affiliation(s)
- Ronald D Mathison
- Department of Physiology and Biophysics, Faculty of Medicine, 3330 Hospital Drive NW, The University of Calgary, Calgary, Alta., Canada T2N 4N1.
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Hashimoto M, Nabeta K, Murakami K. Efficient synthesis of 3-trifluoromethylphenyldiazirinyl oleic acid derivatives and their biological activity for protein kinase C. Bioorg Med Chem Lett 2003; 13:1531-3. [PMID: 12699748 DOI: 10.1016/s0960-894x(03)00200-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
3-trifluoromethylphenyldiazirine based oleic acids derivatives are synthesized to elucidate the functions of specific activation of protein kinase C (PKC) with oleic acid. The synthetic route is based on the alkylation of phenolic derivative with oleic acid equivalent and the post-functionalization of the compound to achieve radiolabeling. Several compounds have biological activity for PKC with similar efficacy with that of oleic acid. The results indicated that the diaizinyl oleic acid derivatives should be useful to study the specific functions of oleic acid for PKC.
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Affiliation(s)
- Makoto Hashimoto
- Department of Bioresource Science, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro 080-8555, Hokkaido, Japan.
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Bordin L, Priante G, Musacchio E, Giunco S, Tibaldi E, Clari G, Baggio B. Arachidonic acid-induced IL-6 expression is mediated by PKC alpha activation in osteoblastic cells. Biochemistry 2003; 42:4485-91. [PMID: 12693944 DOI: 10.1021/bi026842n] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
There are several pieces of evidence supporting the important role that essential fatty acids (EFAs) and their metabolites play in regulating calcium and bone metabolism, and their relevance to the pathobiology of bone disease, with particular reference to modulating effects on cytokines. We found that arachidonic acid (AA) triggers a cell signal in osteoblasts and leads to the expression of IL-6. To explore the biochemical pathways involved in AA induction of cytokine gene expression, we evaluated the potential protein kinase C (PKC) dependent mechanism accounting for the AA effect on IL-6 gene expression. The osteoblast-like cell line MG-63 was pretreated with calphostin C, a PKC inhibitor, or phorbol 12-myristate 13-acetate (PMA) for an extended period, a condition which causes PKC downregulation, and subsequently with AA. After these treatments, IL-6 gene expression was no longer evident. We also showed that PKC and, in particular, PKC alpha, which are both recruited to the particulate fraction, undergo proteolysis and autophosphorylation; all of these steps are required for PKC activation and, subsequently, for AA-induced signaling. It is interesting that other unsaturated fatty acids, such as oleic acid (OA) or eicosapentaenoic acid (EPA), are unable to induce either PKC activation or IL-6 gene expression.
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Affiliation(s)
- Luciana Bordin
- Department of Biological Chemistry, University of Padova, Italy
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Grenier S, Flamand N, Pelletier J, Naccache PH, Borgeat P, Bourgoin SG. Arachidonic acid activates phospholipase D in human neutrophils; essential role of endogenous leukotriene B4 and inhibition by adenosine A2A receptor engagement. J Leukoc Biol 2003; 73:530-9. [PMID: 12660228 DOI: 10.1189/jlb.0702371] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We report in human neutrophils (PMN) that phospholipase D (PLD) was stimulated by micromolar concentrations of arachidonic acid (AA) and nanomolar concentrations of leukotriene B(4) (LTB(4)), and eicosapentaenoic acid was inactive. The stimulatory effect of AA occurred only when adenosine was eliminated from PMN suspensions or when PMN were incubated with adenosine A(2A) receptor antagonists. The mechanism of AA-induced PLD activation was investigated. The results show that AA- and LTB(4)-induced PLD activation were inhibited by the LTB(4) receptor 1 (BLTR1) antagonist CP 105,696, whereas the LTA(4) hydrolase inhibitor SC57461A and the LT biosynthesis inhibitor MK-0591 inhibited AA- but not LTB(4)-mediated PLD activation. The AA-induced ARF1 and RhoA translocation to PMN membranes was inhibited by CP 105,696 and SC57461A. These results provide evidence of a requirement for an autocrine-stimulatory loop involving LTB(4) and BLTR1 in the translocation of small GTPases to membranes and the activation of PMN PLD by AA.
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Affiliation(s)
- Sonya Grenier
- Canadian Institutes for Health Research Group on the Molecular Mechanisms of Inflammation, Centre de Recherche en Rhumatologie et Immunologie, Québec, Canada
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Abstract
PURPOSE OF REVIEW This review critically evaluates recent studies investigating the effects of fatty acids on immune and inflammatory responses in both healthy individuals and in patients with inflammatory diseases, with some reference to animal studies where relevant. It examines recent findings describing the cellular and molecular basis for the modulation of immune function by fatty acids. The newly emerging area of diet-genotype interactions will also be discussed, with specific reference to the anti-inflammatory effects of fish oil. RECENT FINDINGS Fatty acids are participants in many intracellular signalling pathways. They act as ligands for nuclear receptors regulating a host of cell responses, they influence the stability of lipid rafts, and modulate eicosanoid metabolism in cells of the immune system. Recent findings suggest that some or all of these mechanisms may be involved in the modulation of immune function by fatty acids. SUMMARY Human studies investigating the relationship between dietary fatty acids and some aspects of the immune response have been disappointingly inconsistent. This review presents the argument that most studies have not been adequately powered to take into account the influence of variation (genotypic or otherwise) on parameters of immune function. There is well-documented evidence that fatty acids modulate T lymphocyte activation, and recent findings describe a range of potential cellular and molecular mechanisms. However, there are still many questions remaining, particularly with respect to the roles of nuclear receptors, for which fatty acids act as ligands, and the modulation of eicosanoid synthesis, for which fatty acids act as precursors.
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Affiliation(s)
- Parveen Yaqoob
- Hung Sinclair Unit of Human Nutrition, School of Fodd Biosciences, The University of Reading, Reading, UK.
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Zhou J, Fariss RN, Zelenka PS. Synergy of epidermal growth factor and 12(S)-hydroxyeicosatetraenoate on protein kinase C activation in lens epithelial cells. J Biol Chem 2003; 278:5388-98. [PMID: 12464613 DOI: 10.1074/jbc.m209695200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
12(S)-hydroxyeicosatetraenoic acid (12(S)HETE) is a bioactive metabolite of arachidonic acid synthesized by 12-lipoxygenase. The 12-lipoxygenase blocker, baicalein, prevents epidermal growth factor (EGF)-induced activation of protein kinase C (PKC) alpha and beta in lens epithelial cells, whereas supplementation with 12(S)HETE reverses this effect, suggesting that EGF and 12(S)HETE may work together to activate PKC. This study investigates the mechanism of PKCbeta activation by EGF and 12(S)HETE. 12(S)HETE alone directed translocation of PKCbeta through the C1 rather than the C2 domain, without activating phosphoinositide 3-kinase (PI3K) or MAPK signaling or increasing intracellular calcium concentration. In the presence of baicalein, EGF triggered an asymmetric phosphorylation of the EGF receptor initiating signaling through PI3K and MAPK, but not PLCgamma. Together, 12(S)HETE and EGF synergistically increased phosphorylation of PKCbeta in the activation loop and C terminus as well as PKCbeta-specific activity. PI3K inhibitors blocked phosphorylation, but MEK1 inhibitors did not. Microvesicles containing phosphatidylinositol 3,4,5-trisphosphate mimicked the action of EGF on PKCbeta activity in the presence of 12(S)HETE. Kinase-inactive PKCbeta mutations in either activation loop or C terminus were effectively translocated by 12(S)HETE, as was PKCbeta in the presence of chelerythrine or Gö-6983. These findings indicate that unphosphorylated PKCbeta is translocated to the membrane by 12(S)HETE and phosphorylated by EGF-dependent PI3K signaling, to generate catalytically competent PKCbeta.
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Affiliation(s)
- Jianzheng Zhou
- Laboratory of Molecular and Developmental Biology, NEI, National Institutes of Health, Bethesda, Maryland 20892, USA
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Doolan CM, Harvey BJ. A Galphas protein-coupled membrane receptor, distinct from the classical oestrogen receptor, transduces rapid effects of oestradiol on [Ca2+]i in female rat distal colon. Mol Cell Endocrinol 2003; 199:87-103. [PMID: 12581882 DOI: 10.1016/s0303-7207(02)00303-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We examined the hypothesis whether rapid non-genomic effects of oestradiol (E2) on [Ca(2+)](i) are mediated via a membrane-located oestrogen receptor (ER) and further elucidated the signalling pathways involved in rapid non-genomic effects of E2 on [Ca(2+)](i) in distal colonic crypts. Basal [Ca(2+)](i) was significantly increased, within minutes, in response to physiological concentrations of E2. Oestradiol linked to bovine serum albumin (E2-BSA), which renders the E2 membrane impermeable, rapidly increased [Ca(2+)](i) suggesting mediation by a membrane surface receptor. A classical ER is not involved however, as no inhibition of either the E2 or E2-BSA [Ca(2+)](i) response was seen in the presence of the classical ER antagonist ICI 182,780. Treatment with the Galphas inhibitor cholera toxin abolished both E2 and E2-BSA induced Ca(2+) increases. In contrast, treatment with pertussis toxin, an inhibitor of Galphai and Galphao, had no inhibitory effect. Following subsequent additions of E2 and E2-BSA, no further increases in [Ca(2+)](i) were observed, indicating receptor desensitisation. The E2-induced increase in [Ca(2+)](i) was completely abolished by the PKCdelta-specific inhibitor rottlerin, whereas Go6976, an inhibitor of Ca(2+)-sensitive PKC isoforms, was without inhibitory effect. The phospholipase A2 antagonist, quinacrine, and the COX1 inhibitor, indomethacin, abolished the E2-induced increase in [Ca(2+)](i). MAP kinase activation is not involved in rapid stimulatory effects of E2 on [Ca(2+)](i) as the specific inhibitor PD98059 did not inhibit the E2 response. These results demonstrate that rapid E2-induced stimulation of [Ca(2+)](i), in femal rat distal colonic crypts, occurs via a CTx-sensitive Galphas-coupled membrane receptor distinct from the classical ER. PKCdelta and fatty acids are involved in the E2 signalling pathway. In contrast, PKCalpha and MAP kinase are not required.
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Affiliation(s)
- Christina M Doolan
- Department of Physiology, Biosciences Institute, University College Cork, Ireland.
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Eichberg J. Protein kinase C changes in diabetes: is the concept relevant to neuropathy? INTERNATIONAL REVIEW OF NEUROBIOLOGY 2003; 50:61-82. [PMID: 12198821 DOI: 10.1016/s0074-7742(02)50073-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Protein kinase C (PKC) comprises a superfamily of isoenzymes, many of which are activated by 1,2-diacylglycerol (DAG) in the presence of phosphatidylserine. In order to be capable of DAG activation, PKC must first undergo a series of phosphorylation at three conserved sites. PKC isoforms phosphorylate a wide variety of intracellular target proteins and have multiple functions in signal transduction-mediated cellular regulation. An elevation in DAG levels and an increase in composite PKC activity and/or certain isoforms occurs in several nonneural tissues from diabetic animals, including the vasculature. The ability of isoform-specific PKC inhibitors to antagonize diabetes-induced abnormalities has implicated altered PKC beta activity in the onset of several diabetic complications, In contrast to many other tissues, DAG levels fall in diabetic nerve and a consistent pattern of change in PKC activity has not been observed. Treatments that alter PKC activity affect nerve Na+, K+-ATPase activity, but the mechanism involved is not well understood, Inhibition of PKC beta in diabetic rats appears to correct reduced nerve blood flow and decreased nerve conduction velocity. These and other findings indicate that changes in the neurovasculature exert adverse effects during the pathogenesis of diabetic neuropathy. Still unresolved is a clear-cut role for PKC in the development of abnormalities in neural cell metabolism. Further progress will depend on a more complete understanding of the functions of individual PKC isoforms in nerve. Future investigation could focus profitably on biochemical processes in nerve cells that modulate PKC activity and that are altered in diabetes, such as vascular endothelial growth factor levels and production of reactive oxygen species arising from oxidative stress.
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Affiliation(s)
- Joseph Eichberg
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204, USA
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Sopalla C, Leukert N, Sorg C, Kerkhoff C. Evidence for the involvement of the unique C-tail of S100A9 in the binding of arachidonic acid to the heterocomplex S100A8/A9. Biol Chem 2002; 383:1895-905. [PMID: 12553726 DOI: 10.1515/bc.2002.213] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Protein complexes formed by S100A8 and S100A9 represent the only AA-binding capacity in the human neutrophilic cytosol and are involved in the intracellular arachidonic acid metabolism. The formation of S100A8/A9 protein complexes and the binding of calcium to the complexes are prerequisites for the specific binding of polyunsaturated fatty acids. The present study was undertaken to characterize the fatty acid binding site within the protein complex. Deletions at both termini and point mutations of different basic amino acids especially within the extended C-terminal tail of human S100A9 were introduced. The S100A9 mutant proteins were then analyzed with respect to protein-protein interaction (GST pull down-assay and yeast two-hybrid system) and functional properties (arachidonic acid and calcium binding). The data give strong evidence that the unique C-tail of S100A9 containing the three consecutive histidine residues (His103-His105) represents the region to which the fatty acid carboxy-group is bound to the protein complex. The localization of the AA-binding site within the unique C-tail of S100A9 correlates with the fact that fatty acid binding has not yet been reported for other S100 proteins.
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Affiliation(s)
- Claudia Sopalla
- Institute of Experimental Dermatology, University of Münster, von-Esmarch-Str. 58, D-48149 Münster, Germany
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