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Ottenlinger F, Schwiebs A, Pfarr K, Wagner A, Grüner S, Mayer CA, Pfeilschifter JM, Radeke HH. Fingolimod targeting protein phosphatase 2A differently affects IL-33 induced IL-2 and IFN-γ production in CD8(+) lymphocytes. Eur J Immunol 2016; 46:941-51. [PMID: 26683421 DOI: 10.1002/eji.201545805] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 11/02/2015] [Accepted: 12/10/2015] [Indexed: 01/05/2023]
Abstract
Multiple sclerosis patients are treated with fingolimod (FTY720), a prodrug that acts as an immune modulator. FTY720 is first phosphorylated to FTY720-P and then internalizes sphingosine-1-phosphate receptors, preventing lymphocyte sequestration. IL-33 is released from necrotic endothelial cells and contributes to MS severity by coactivating T cells. Herein we analyzed the influence of FTY720, FTY720-P, and S1P on IL-33 induced formation of IL-2 and IFN-γ, by using IL-33 receptor overexpressing EL4 cells, primary CD8(+) T cells, and splenocytes. EL4-ST2 cells released IL-2 after IL-33 stimulation that was inhibited dose-dependently by FTY720-P but not FTY720. In this system, S1P increased IL-2, and accordingly, inhibition of S1P producing sphingosine kinases diminished IL-2 release. In primary CD8(+) T cells and splenocytes IL-33/IL-12 stimulation induced IFN-γ, which was prevented by FTY720 but not FTY720-P, independently from intracellular phosphorylation. The inhibition of IFN-γ by nonphosphorylated FTY720 was mediated via the SET/protein phosphatase 2A (PP2A) pathway, since a SET peptide antagonist also prevented IFN-γ formation and the inhibition of IFN-γ by FTY720 was reversible by a PP2A inhibitor. While our findings directly improve the understanding of FTY720 therapy in MS, they could also contribute to side effects of FTY720 treatment, like progressive multifocal leukoencephalopathy, caused by an insufficient immune response to a viral infection.
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Affiliation(s)
- Florian Ottenlinger
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Anja Schwiebs
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Kathrin Pfarr
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Annika Wagner
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Sophia Grüner
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Christoph A Mayer
- Center for Neurology and Neurosurgery, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Josef M Pfeilschifter
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Heinfried H Radeke
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
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2
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Steady-state modulation of voltage-gated K+ channels in rat arterial smooth muscle by cyclic AMP-dependent protein kinase and protein phosphatase 2B. PLoS One 2015; 10:e0121285. [PMID: 25793374 PMCID: PMC4368632 DOI: 10.1371/journal.pone.0121285] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 01/29/2015] [Indexed: 01/17/2023] Open
Abstract
Voltage-gated potassium channels (Kv) are important regulators of membrane potential in vascular smooth muscle cells, which is integral to controlling intracellular Ca2+ concentration and regulating vascular tone. Previous work indicates that Kv channels can be modulated by receptor-driven alterations of cyclic AMP-dependent protein kinase (PKA) activity. Here, we demonstrate that Kv channel activity is maintained by tonic activity of PKA. Whole-cell recording was used to assess the effect of manipulating PKA signalling on Kv and ATP-dependent K+ channels of rat mesenteric artery smooth muscle cells. Application of PKA inhibitors, KT5720 or H89, caused a significant inhibition of Kv currents. Tonic PKA-mediated activation of Kv appears maximal as application of isoprenaline (a β-adrenoceptor agonist) or dibutyryl-cAMP failed to enhance Kv currents. We also show that this modulation of Kv by PKA can be reversed by protein phosphatase 2B/calcineurin (PP2B). PKA-dependent inhibition of Kv by KT5720 can be abrogated by pre-treatment with the PP2B inhibitor cyclosporin A, or inclusion of a PP2B auto-inhibitory peptide in the pipette solution. Finally, we demonstrate that tonic PKA-mediated modulation of Kv requires intact caveolae. Pre-treatment of the cells with methyl-β-cyclodextrin to deplete cellular cholesterol, or adding caveolin-scaffolding domain peptide to the pipette solution to disrupt caveolae-dependent signalling each attenuated PKA-mediated modulation of the Kv current. These findings highlight a novel, caveolae-dependent, tonic modulatory role of PKA on Kv channels providing new insight into mechanisms and the potential for pharmacological manipulation of vascular tone.
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Vasauskas AA, Chen H, Wu S, Cioffi DL. The serine-threonine phosphatase calcineurin is a regulator of endothelial store-operated calcium entry. Pulm Circ 2014; 4:116-27. [PMID: 25006427 DOI: 10.1086/675641] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 01/15/2014] [Indexed: 01/25/2023] Open
Abstract
Disruption of the endothelium leads to increased permeability, allowing extravasation of macromolecules and other solutes from blood vessels. Calcium entry through a calcium-selective, store-operated calcium (SOC) channel, I soc, contributes to barrier disruption. An understanding of the mechanisms surrounding the regulation of I soc is far from complete. We show that the calcium/calmodulin-activated phosphatase calcineurin (CN) plays a role in regulation of SOC entry, possibly through the dephosphorylation of stromal interaction molecule 1 (STIM1). Phosphorylation has been implicated as a regulatory mechanism of activity for a number of canonical transient receptor potential (TRPC) and SOC channels, including I soc. Our results show that STIM1 phosphorylation increases in pulmonary artery endothelial cells (PAECs) upon activation of SOC entry. However, the phosphatases involved in STIM1 dephosphorylation are unknown. We found that a CN inhibitor (calcineurin inhibitory peptide [CIP]) increases the phosphorylation pattern of STIM1. Using a fura 2-acetoxymethyl ester approach to measure cytosolic calcium in PAECs, we found that CIP decreases SOC entry following thapsigargin treatment in PAECs. Luciferase assays indicate that thapsigargin induces activation of CN activity and confirm inhibition of CN activity by CIP in PAECs. Also, I soc is significantly attenuated in whole-cell patch-clamp studies of PAECs treated with CIP. Finally, PAECs pretreated with CIP exhibit decreased interendothelial cell gap formation in response to thapsigargin-induced SOC entry, as compared to control cells. Taken together, our data show that CN contributes to the phosphorylation status of STIM1, which is important in regulation of endothelial SOC entry and I soc activity.
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Affiliation(s)
- Audrey A Vasauskas
- Departments of Biochemistry and Molecular Biology and Center for Lung Biology, University of South Alabama, Mobile, Alabama, USA
| | - Hairu Chen
- Department of Anesthesiology and Perioperative Medicine, Georgia Regents University, Augusta, Georgia, USA
| | - Songwei Wu
- Department of Anesthesiology and Perioperative Medicine, Georgia Regents University, Augusta, Georgia, USA
| | - Donna L Cioffi
- Departments of Biochemistry and Molecular Biology and Center for Lung Biology, University of South Alabama, Mobile, Alabama, USA
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Hall G, Rowell J, Farinelli F, Gbadegesin RA, Lavin P, Wu G, Homstad A, Malone A, Lindsey T, Jiang R, Spurney R, Tomaselli GF, Kass DA, Winn MP. Phosphodiesterase 5 inhibition ameliorates angiontensin II-induced podocyte dysmotility via the protein kinase G-mediated downregulation of TRPC6 activity. Am J Physiol Renal Physiol 2014; 306:F1442-50. [PMID: 24740790 DOI: 10.1152/ajprenal.00212.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The emerging role of the transient receptor potential cation channel isotype 6 (TRPC6) as a central contributor to various pathological processes affecting podocytes has generated interest in the development of therapeutics to modulate its function. Recent insights into the regulation of TRPC6 have revealed PKG as a potent negative modulator of TRPC6 conductance and associated signaling via its phosphorylation at two highly conserved amino acid residues: Thr(69)/Thr(70) (Thr(69) in mice and Thr(70) in humans) and Ser(321)/Ser(322) (Ser(321) in mice and Ser(322) in humans). Here, we tested the role of PKG in modulating TRPC6-dependent responses in primary and conditionally immortalized mouse podocytes. TRPC6 was phosphorylated at Thr(69) in nonstimulated podocytes, but this declined upon ANG II stimulation or overexpression of constitutively active calcineurin phosphatase. ANG II induced podocyte motility in an in vitro wound assay, and this was reduced 30-60% in cells overexpressing a phosphomimetic mutant TRPC6 (TRPC6T70E/S322E) or activated PKG (P < 0.05). Pretreatment of podocytes with the PKG agonists S-nitroso-N-acetyl-dl-penicillamine (nitric oxide donor), 8-bromo-cGMP, Bay 41-2772 (soluble guanylate cyclase activator), or phosphodiesterase 5 (PDE5) inhibitor 4-{[3',4'-(methylenedioxy)benzyl]amino}[7]-6-methoxyquinazoline attenuated ANG II-induced Thr(69) dephosphorylation and also inhibited TRPC6-dependent podocyte motility by 30-60%. These data reveal that PKG activation strategies, including PDE5 inhibition, ameliorate ANG II-induced podocyte dysmotility by targeting TRPC6 in podocytes, highlighting the potential therapeutic utility of these approaches to treat hyperactive TRPC6-dependent glomerular disease.
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Affiliation(s)
- Gentzon Hall
- Division of Nephrology, Duke University Medical Center, Durham, North Carolina; Center for Human Genetics, Duke University Medical Center, Durham, North Carolina
| | - Janelle Rowell
- Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Federica Farinelli
- Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Rasheed A Gbadegesin
- Division of Nephrology, Duke University Medical Center, Durham, North Carolina; Center for Human Genetics, Duke University Medical Center, Durham, North Carolina; Department of Pediatrics, Duke University Medical Center, Durham, North Carolina; and
| | - Peter Lavin
- Trinity Health Kidney Centre, Tallaght Hospital, Trinity College, Dublin, Ireland
| | - Guanghong Wu
- Center for Human Genetics, Duke University Medical Center, Durham, North Carolina
| | - Alison Homstad
- Center for Human Genetics, Duke University Medical Center, Durham, North Carolina
| | - Andrew Malone
- Division of Nephrology, Duke University Medical Center, Durham, North Carolina; Center for Human Genetics, Duke University Medical Center, Durham, North Carolina
| | - Thomas Lindsey
- Center for Human Genetics, Duke University Medical Center, Durham, North Carolina
| | - Ruiji Jiang
- Center for Human Genetics, Duke University Medical Center, Durham, North Carolina
| | - Robert Spurney
- Division of Nephrology, Duke University Medical Center, Durham, North Carolina
| | - Gordon F Tomaselli
- Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - David A Kass
- Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Michelle P Winn
- Division of Nephrology, Duke University Medical Center, Durham, North Carolina; Center for Human Genetics, Duke University Medical Center, Durham, North Carolina;
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Cano-Colino M, Almeida R, Gomez-Cabrero D, Artigas F, Compte A. Serotonin regulates performance nonmonotonically in a spatial working memory network. ACTA ACUST UNITED AC 2013; 24:2449-63. [PMID: 23629582 DOI: 10.1093/cercor/bht096] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The prefrontal cortex (PFC) contains a dense network of serotonergic [serotonin, 5-hydroxytryptamine (5-HT)] axons, and endogenous 5-HT markedly modulates PFC neuronal function via several postsynaptic receptors. The therapeutic action of atypical antipsychotic drugs, acting mainly via 5-HT receptors, also suggests a role for serotonergic neurotransmission in cognitive functions. However, psychopharmacological studies have failed to find a consistent relationship between serotonergic transmission and cognitive functions of the PFC, including spatial working memory (SWM). Here, we built a computational network model to investigate 5-HT modulation of SWM in the PFC. We found that 5-HT modulates network's SWM performance nonmonotonically via 5-HT1A and 5-HT2A receptors, following an inverted U-shape. This relationship may contribute to blur the effects of serotonergic agents in previous SWM group-based behavioral studies. Our simulations also showed that errors occurring at low and high 5-HT concentrations are due to different network dynamics instabilities, suggesting that these 2 conditions can be distinguished experimentally based on their distinct dependency on experimental variables. We inferred specific predictions regarding the expected behavioral effects of serotonergic agents in 2 classic working-memory tasks. Our results underscore the relevance of identifying different error types in SWM tasks in order to reveal the association between neuromodulatory systems and SWM.
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Affiliation(s)
- Maria Cano-Colino
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Rita Almeida
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain, Department of Neuroscience
| | - David Gomez-Cabrero
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain, Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | - Francesc Artigas
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain, Institut d'Investigacions Biomèdiques de Barcelona (IIBB)-CSIC, Barcelona, Spain and Centro de Investigación Biomédica en Salud Mental (CIBERSAM), Barcelona, Spain
| | - Albert Compte
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
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Abstract
Nonsteroidal medications, previously unfamiliar in the management of autoimmune hepatitis, can supplement or replace conventional corticosteroid regimens, especially in problematic patients. Mycophenolate mofetil is a next-generation purine antagonist that has been useful in treating patients with azathioprine intolerance. It has been less effective in salvaging patients with steroid-refractory disease. Azathioprine is the choice as a corticosteroid-sparing agent in treatment-naive patients and in individuals with corticosteroid intolerance, incomplete response and relapse after drug withdrawal. Tacrolimus is preferred over cyclosporine for recalcitrant disease because of its established preference in organ transplantation, but replacement with cyclosporine should be considered if the disease worsens on treatment. Rapamycin has antiproliferative and proapoptotic actions that warrant further study in autoimmune hepatitis. The nonstandard, nonsteroidal medications are mainly salvage therapies with off-label indications that must be used in highly individualized and well-monitored clinical situations.
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Affiliation(s)
- Albert J Czaja
- Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA.
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7
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Advances in the current treatment of autoimmune hepatitis. Dig Dis Sci 2012; 57:1996-2010. [PMID: 22476586 DOI: 10.1007/s10620-012-2151-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 03/16/2012] [Indexed: 12/17/2022]
Abstract
Current treatment strategies for autoimmune hepatitis are complicated by frequent relapse after drug withdrawal, medication intolerance, and refractory disease. The objective of this review is to describe advances that have improved treatment outcomes by defining the optimum objectives of initial therapy, managing relapse more effectively, identifying problematic patients early, and incorporating the new pharmacological interventions that have emerged as frontline and salvage therapies. Initial corticosteroid treatment should be continued until serum aminotransferase, γ-globulin, and immunoglobulin G levels are normal, and maintenance of this improvement for 3-8 months before liver tissue assessment. Improvement to normal liver tissue is the ideal histological result that justifies drug withdrawal, but it is achievable in only 22 % of patients. Minimum portal hepatitis, inactive cirrhosis, or minimally active cirrhosis is the most common treatment end point. Relapse after drug withdrawal warrants institution of a long-term maintenance regimen, preferably with azathioprine. Mathematical models can identify problematic adult patients early, as also can clinical phenotype (age ≤ 30 years and HLA DRB1 03), rapidity of treatment response (≤ 24 months), presence of antibodies to soluble liver antigen, and non-white ethnicity. The calcineurin inhibitors (cyclosporine and tacrolimus) can be effective in steroid-refractory disease; mycophenolate mofetil can be corticosteroid-sparing and effective for azathioprine intolerance; budesonide combined with azathioprine can be effective for treatment-naïve, non-cirrhotic patients. Standard treatment regimens for autoimmune hepatitis can be upgraded without adjustments that require major new expertise.
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Yan X, Gao S, Tang M, Xi J, Gao L, Zhu M, Luo H, Hu X, Zheng Y, Hescheler J, Liang H. Adenylyl cyclase/cAMP-PKA-mediated phosphorylation of basal L-type Ca(2+) channels in mouse embryonic ventricular myocytes. Cell Calcium 2011; 50:433-43. [PMID: 21824653 DOI: 10.1016/j.ceca.2011.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 06/16/2011] [Accepted: 07/12/2011] [Indexed: 10/17/2022]
Abstract
In fetal mammalian heart, constitutive adenylyl cyclase/cyclic AMP-dependent protein kinase A (cAMP-PKA)-mediated phosphorylation, independent of β-adrenergic receptor stimulation, could under such circumstances play an important role in sustaining the L-type calcium channel current (I(Ca,L)) and regulating other PKA dependent phosphorylation targets. In this study, we investigated the regulation of L-type Ca(2+) channel (LTCC) in murine embryonic ventricles. The data indicated a higher phosphorylation state of LTCC at early developmental stage (EDS, E9.5-E11.5) than late developmental stage (LDS, E16.5-E18.5). An intrinsic adenylyl cyclase (AC) activity, PKA activity and basal cAMP concentration were obviously higher at EDS than LDS. The cAMP increase in the presence of isobutylmethylxanthine (IBMX, nonselective phosphodiesterase inhibitor) was further augmented at LDS but not at EDS by chelation of intracellular Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA)-acetoxymethyl ester (BAPTA-AM). Furthermore, I(Ca,L) increased with time after patch rupture in LDS cardiomyocytes dialyzed with pipette solution containing BAPTA whereas not at EDS. Thus we conclude that the high basal level of LTCC phosphorylation is due to the high intrinsic PKA activity and the high intrinsic AC activity at EDS. The latter is possibly owing to the little or no effect of Ca(2+) influx via LTCCs on AC activity, leading to the inability to inhibit AC.
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Affiliation(s)
- Xisheng Yan
- Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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