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Sun B, Smith N, Dixon AJ, Osei-Owusu P. Phosphodiesterases Mediate the Augmentation of Myogenic Constriction by Inhibitory G Protein Signaling and is Negatively Modulated by the Dual Action of RGS2 and 5. FUNCTION 2024; 5:zqae003. [PMID: 38486977 PMCID: PMC10935470 DOI: 10.1093/function/zqae003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/09/2024] [Accepted: 01/16/2024] [Indexed: 03/17/2024] Open
Abstract
G protein regulation by regulators of G protein signaling (RGS) proteins play a key role in vascular tone maintenance. The loss of Gi/o and Gq/11 regulation by RGS2 and RGS5 in non-pregnant mice is implicated in augmented vascular tone and decreased uterine blood flow (UBF). RGS2 and 5 are closely related and co-expressed in uterine arteries (UA). However, whether and how RGS2 and 5 coordinate their regulatory activities to finetune G protein signaling and regulate vascular tone are unclear. Here, we determined how the integrated activity of RGS2 and 5 modulates vascular tone to promote UBF. Using ultrasonography and pressure myography, we examined uterine hemodynamics and myogenic tone (MT) of UA of wild type (WT), Rgs2-/-, Rgs5-/-, and Rgs2/5 dbKO mice. We found that MT was reduced in Rgs5-/- relative to WT or Rgs2-/- UA. Activating Gi/o with dopamine increased, whereas exogenous cAMP decreased MT in Rgs5-/- UA to levels in WT UA. Dual deletion of Rgs2 and 5 abolished the reduced MT due to the absence of Rgs5 and enhanced dopamine-induced Gi/o effects in Rgs2/5 dbKO UA. Conversely, and as in WT UA, Gi/o inhibition with pertussis toxin or exogenous cAMP decreased MT in Rgs2/5 dbKO to levels in Rgs5-/- UA. Inhibition of phosphodiesterases (PDE) concentration-dependently decreased and normalized MT in all genotypes, and blocked dopamine-induced MT augmentation in Rgs2-/-, Rgs5-/-, and Rgs2/5 dbKO UA. We conclude that Gi/o augments UA MT in the absence of RGS2 by a novel mechanism involving PDE-mediated inhibition of cAMP-dependent vasodilatation..
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Affiliation(s)
- Bo Sun
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Nia Smith
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Alethia J Dixon
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Patrick Osei-Owusu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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Drug Repositioning of the α 1-Adrenergic Receptor Antagonist Naftopidil: A Potential New Anti-Cancer Drug? Int J Mol Sci 2020; 21:ijms21155339. [PMID: 32727149 PMCID: PMC7432507 DOI: 10.3390/ijms21155339] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/22/2020] [Accepted: 07/25/2020] [Indexed: 12/16/2022] Open
Abstract
Failure of conventional treatments is often observed in cancer management and this requires the development of alternative therapeutic strategies. However, new drug development is known to be a high-failure process because of the possibility of a lower efficacy than expected for the drug or appearance of non-manageable side effects. Another way to find alternative therapeutic drugs consists in identifying new applications for drugs already approved for a particular disease: a concept named "drug repurposing". In this context, several studies demonstrated the potential anti-tumour activity exerted by α1-adrenergic receptor antagonists and notably renewed interest for naftopidil as an anti-cancer drug. Naftopidil is used for benign prostatic hyperplasia management in Japan and a retrospective study brought out a reduced incidence of prostate cancer in patients that had been prescribed this drug. Further studies showed that naftopidil exerted anti-proliferative and cytotoxic effects on prostate cancer as well as several other cancer types in vitro, as well as ex vivo and in vivo. Moreover, naftopidil was demonstrated to modulate the expression of Bcl-2 family pro-apoptotic members which could be used to sensitise cancer cells to targeting therapies and to overcome resistance of cancer cells to apoptosis. For most of these anti-cancer effects, the molecular pathway is either not fully deciphered or shown to involve α1-adrenergic receptor-independent pathway, suggesting off target transduction signals. In order to improve its efficacy, naftopidil analogues were designed and shown to be effective in several studies. Thereby, naftopidil appears to display anti-cancer properties on different cancer types and could be considered as a candidate for drug repurposing although its anti-cancerous activities need to be studied more deeply in prospective randomized clinical trials.
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Vaessen SFC, Bruysters MWP, Vandebriel RJ, Verkoeijen S, Bos R, Krul CAM, Akkermans AM. Toward a mechanism-based in vitro safety test for pertussis toxin. Hum Vaccin Immunother 2014; 10:1391-5. [PMID: 24553455 DOI: 10.4161/hv.28001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Pertussis vaccines are routinely administered to infants to protect them from whooping cough. Still, an adequate safety test for pertussis toxin (PT), one of the main antigens in these vaccines, is not available. The histamine sensitization test is currently the only assay accepted by regulatory authorities to test for the absence of active PT in vaccines. This is however, a lethal animal test with poor reproducibility. In addition, it is not clear whether the assumed underlying mechanism, i.e., ADP-ribosylation of G proteins, is the only effect that should be considered in safety evaluation of PT. The in vitro safety test for PT that we developed is based on the clinical effects of PT in humans. For this, human cell lines were chosen based on the cell types involved in the clinical effects of PT. These cell lines were exposed to PT and analyzed by microarray. In this review, we discuss the clinical effects of PT and the mechanisms that underlie them. The approach taken may provide as an example for other situations in which an in vitro assay based on clinical effects in humans is required.
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Affiliation(s)
- Stefan F C Vaessen
- Research Centre Technology & Innovation; Innovative testing in Life sciences and Chemistry; University of Applied Sciences; Utrecht, the Netherlands
| | - Martijn W P Bruysters
- Center for Health Protection; National Institute for Public Health and the Environment; Bilthoven, the Netherlands
| | - Rob J Vandebriel
- Center for Health Protection; National Institute for Public Health and the Environment; Bilthoven, the Netherlands
| | - Saertje Verkoeijen
- Research Centre Technology & Innovation; Innovative testing in Life sciences and Chemistry; University of Applied Sciences; Utrecht, the Netherlands
| | - Rogier Bos
- Central Committee on Research Involving Human Subjects; Den Haag, the Netherlands
| | - Cyrille A M Krul
- Research Centre Technology & Innovation; Innovative testing in Life sciences and Chemistry; University of Applied Sciences; Utrecht, the Netherlands
| | - Arnoud M Akkermans
- Center for Health Protection; National Institute for Public Health and the Environment; Bilthoven, the Netherlands
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Hoonakker ME, Ruiterkamp N, Hendriksen CFM. The cAMP assay: a functional in vitro alternative to the in vivo Histamine Sensitization test. Vaccine 2009; 28:1347-52. [PMID: 19941995 DOI: 10.1016/j.vaccine.2009.11.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 10/19/2009] [Accepted: 11/05/2009] [Indexed: 10/20/2022]
Abstract
Safety requirements stipulate the performance of the in vivo Histamine Sensitization (HS) test for quality control of acellular pertussis (aP) vaccines. For reasons of reproducibility and animal welfare concern, an in vitro assay was developed. The assay reflects the mechanism of histamine sensitization and is based on cAMP production in A10 cells to residual pertussis toxin (PT). We showed that PT induces cAMP levels in a dose-dependent manner while the sensitivity of the assay equals the sensitivity of the HS test. Neither the individual components nor the combination vaccine DTaP-IP did affect the assay. The cAMP assay meets the criteria for specificity and sensitivity and therefore might be a promising candidate to replace the HS test.
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Affiliation(s)
- Marieke E Hoonakker
- Netherlands Vaccine Institute (NVI), P.O. Box 457, 3720 AL Bilthoven, The Netherlands.
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Hein P, Michel MC. Signal transduction and regulation: are all alpha1-adrenergic receptor subtypes created equal? Biochem Pharmacol 2006; 73:1097-106. [PMID: 17141737 DOI: 10.1016/j.bcp.2006.11.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 10/30/2006] [Accepted: 11/01/2006] [Indexed: 02/06/2023]
Abstract
The current manuscript reviews the evidence whether and how subtypes of alpha(1)-adrenergic receptors, i.e. alpha(1A)-, alpha(1B)- and alpha(1D)-adrenergic receptors, differentially couple to signal transduction pathways and exhibit differential susceptibility to regulation. In both regards studies in tissues or cells natively expressing the subtypes are hampered because the relative expression of the subtypes is poorly controlled and the observed effects may be cell-type specific. An alternative approach, i.e. transfection of multiple subtypes into the same host cell line overcomes this limitation, but it often remains unclear whether results in such artificial systems are representative for the physiological situation. The overall evidence suggests that indeed subtype-intrinsic and cell type-specific factors interact to direct alpha(1)-adrenergic receptor signaling and regulation. This may explain why so many apparently controversial findings have been reported from various tissues and cells. One of the few consistent themes is that alpha(1D)-adrenergic receptors signal less effectively upon agonist stimulation than the other subtypes, most likely because they exhibit spontaneous internalization.
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Affiliation(s)
- Peter Hein
- Department of Pharmacology, University of Würzburg, Würzburg, Germany
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Abstract
Heterotrimeric G proteins are key players in transmembrane signaling by coupling a huge variety of receptors to channel proteins, enzymes, and other effector molecules. Multiple subforms of G proteins together with receptors, effectors, and various regulatory proteins represent the components of a highly versatile signal transduction system. G protein-mediated signaling is employed by virtually all cells in the mammalian organism and is centrally involved in diverse physiological functions such as perception of sensory information, modulation of synaptic transmission, hormone release and actions, regulation of cell contraction and migration, or cell growth and differentiation. In this review, some of the functions of heterotrimeric G proteins in defined cells and tissues are described.
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Affiliation(s)
- Nina Wettschureck
- Institute of Pharmacology, University of Heidelberg, Im Neuenheimer Feld 366, D-69120 Heidelberg, Germany
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Kleinz MJ, Skepper JN, Davenport AP. Immunocytochemical localisation of the apelin receptor, APJ, to human cardiomyocytes, vascular smooth muscle and endothelial cells. ACTA ACUST UNITED AC 2005; 126:233-40. [PMID: 15664671 DOI: 10.1016/j.regpep.2004.10.019] [Citation(s) in RCA: 213] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Revised: 10/06/2004] [Accepted: 10/07/2004] [Indexed: 10/26/2022]
Abstract
The novel G protein-coupled receptor APJ, recently paired with the proposed cognate peptide ligand apelin, mediates potent vasodilator and positive inotropic actions in rats. Radioligand binding showed apelin receptors in rat and human heart and human large conduit vessels. The specific cell types expressing the receptor, however, have not been determined. Apelin, the cognate receptor ligand, is present in endothelial cells. However, the exact pathway of endothelial apelin synthesis and secretion is not known. We therefore investigated the cellular distribution of APJ receptor-like immunoreactivity (APJ-LI) in a range of human tissues using immunocytochemistry and fluorescent double staining confocal microscopy. The same techniques were applied to determine the intracellular localisation of apelin-like immunoreactivity (apelin-LI) in cultured human umbilical vein endothelial cells (HUVECs). APJ-LI is present in endothelial cells, vascular smooth muscle cells and cardiomyocytes. Apelin-LI localises to secretory vesicles and the Golgi complex/endoplasmic reticulum of HUVECs. Apelin-LI does not co-localise with von Willebrand factor in Weibel-Palade bodies, suggesting synthesis of apelin via the constitutive pathway. The proximity of receptor and ligand in the human vasculature, together with evidence for local vascular apelin synthesis, suggests an important role for APJ/apelin as a paracrine cardiovascular regulator system.
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Affiliation(s)
- Matthias J Kleinz
- Clinical Pharmacology Unit, University of Cambridge, Level 6, Centre for Clinical Investigation, Box 110 Addenbrooke's Hospital, Cambridge, CB2 2QQ, UK.
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Bennett MR, Farnell L, Gibson WG. A quantitative description of the contraction of blood vessels following the release of noradrenaline from sympathetic varicosities. J Theor Biol 2005; 234:107-22. [PMID: 15721040 DOI: 10.1016/j.jtbi.2004.11.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Revised: 10/23/2004] [Accepted: 11/11/2004] [Indexed: 11/24/2022]
Abstract
A model is presented that highlights the principal factors determining the form and extent of contraction in arteries upon stimulation of their sympathetic nerve supply. This model incorporates a previous quantitative model of the process of noradrenaline (NAd) diffusion into the vascular media and reuptake into sympathetic varicosities during nerve stimulation (J. Theor. Biol. 226 (2004) 359). It is also dependent on a model of how the subsequent activation of metabotropic receptors initiates a G-protein cascade, resulting in the production of inositol trisphosphate (IP3) and an increase in intracellular calcium concentration, [Ca2+]i, in the smooth muscle cells (J. Theor. Biol. 223 (2003) 93). In the present work we couple this rise in [Ca2+]i to the increase in phosphorylated myosin bound to actin in the cells and hence determine the force development in arteries due to nerve stimulation. The model accounts for force development as a function of [Ca2+]i and for the rate of change of force as a function of the rate of change of [Ca2+]i in single smooth muscle cells. It also accounts for the characteristic time course of the force developed by the media of the rat-tail artery upon nerve stimulation. This consists of a rapid rise to a transient peak followed by a sustained plateau of contraction during the stimulation period, after which the contraction slowly decays back to baseline at a rate dependent on the strength of the stimulation. The model indicates that the transient peak is primarily due to the partial block of the IP3 receptor by the rise in [Ca2+]i and that the main determinant of the equilibrium condition indicated by the plateau phase is the rate of pumping of calcium into the sarcoplasmic reticulum. The relatively slow decline of contraction at the end of nerve stimulation is primarily a consequence of the slow rates of removal of NAd from the media by diffusion and reuptake into the sympathetic varicosities. The model thus provides a quantitative account of vascular smooth muscle contraction upon sympathetic nerve stimulation.
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Affiliation(s)
- M R Bennett
- The Neurobiology Laboratory, Department of Physiology, and Institute for Biomedical Research, University of Sydney, NSW, 2006, Australia.
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van Meijeren CE, Vleeming W, Dormans JAMA, van de Kuil T, Opperhuizen A, Hendriksen CFM, de Wildt DJ. Pertussis toxin relaxes small arteries with no vascular lesions or vascular smooth muscle cell injury. ACTA ACUST UNITED AC 2004; 56:139-43. [PMID: 15625782 DOI: 10.1016/j.etp.2004.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Previous studies showed that pertussis toxin (PT) decreased agonist-induced contractions of isolated rat small mesenteric resistance arteries independently from endothelium, nitric oxide-synthase or intracellular calcium concentrations. In this study, it was investigated if the PT-induced decreased contractile properties of small mesenteric resistance arteries could be a consequence of a PT-induced vascular and/or smooth muscle cell injury, leading to loss of contractile functionality. Male Wistar rats were treated with PT (30 microg/kg, intravenously) and sections of isolated small mesenteric resistance arteries were investigated with light- and electron microscopy. Light microscopic investigation of cross-sectioned small mesenteric resistance arteries of control animals clearly showed a contracted phase, while PT-pretreated animals showed a relaxed smooth inner surface of the vessel, indicating a vasodilated state. Electron microscopic investigation showed that PT-pretreatment neither induced vascular lesions nor caused morphological or numerical changes in cell organelles such as contractile elements of vascular smooth muscle cells. In conclusion, the PT-induced decreased contractile properties of isolated rat small resistance arteries are not caused by a PT-induced vascular and/or smooth muscle cell injury.
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Affiliation(s)
- Cornelia E van Meijeren
- Laboratory of Toxicology, Pathology and Genetics, National Institute for Public Health and the Environment, 3720 BA Bilthoven, The Netherlands.
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van Meijeren CE, Vleeming W, van de Kuil T, Gerards AL, Hendriksen CFM, de Wildt DJ. Pertussis toxin-induced histamine sensitisation: an aspecific phenomenon independent from the nitric oxide system? Eur J Pharmacol 2004; 493:139-50. [PMID: 15189775 DOI: 10.1016/j.ejphar.2004.04.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2004] [Revised: 04/05/2004] [Accepted: 04/09/2004] [Indexed: 11/27/2022]
Abstract
Mechanisms were studied initially to develop an in vitro safety test for detecting pertussis toxin toxicity in acellular pertussis vaccines based on the histamine sensitisation test. Maximal contractions and sensitivities to different agonists and adrenoceptor-induced contractions in Ca2+-free medium of isolated rat small mesenteric resistance arteries were significantly reduced by in vivo [30 microg/kg, intravenously (i.v.), day 5] or in vitro (10 microg/ml, 2 h) pertussis toxin pretreatment. Pertussis toxin-induced decrease in sensitivity of small mesenteric resistance arteries to noradrenaline was endothelium-dependent. Nomega-nitro-L-arginine methyl ester (L-NAME) (100 microM, 20 min) did not reestablish the sensitivity to noradrenaline. In vivo L-NAME treatment (0, 1, 10 or 30 mg/kg) of pertussis toxin-pretreated (15 microg/kg) rats did not reduce pertussis toxin-induced enhancement of the histamine-induced decrease in blood pressure and histamine (10, 30, 100 or 300 mg/kg) induced mortality. Finally, in vivo pertussis toxin pretreatment sensitises rats for sodium nitroprusside (50 microg/kg/min). We conclude that pertussis toxin-induced histamine sensitisation is caused by an interference of pertussis toxin with the contractile mechanisms of vascular smooth muscle of resistance arteries which indicates only an indirect role for histamine in the histamine sensitisation test.
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Affiliation(s)
- Cornelia E van Meijeren
- National Institute for Public Health and the Environment, Laboratory of Toxicology, Pathology and Genetics, P.O. Box 1, 3720 BA Bilthoven, The Netherlands.
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van Meijeren CE, Vleeming W, van de Kuil T, Manni J, Kegler D, Hendriksen CFM, de Wildt DJ. In vivo pertussis toxin treatment reduces contraction of rat resistance arteries but not that of mouse trachea. Eur J Pharmacol 2004; 488:127-35. [PMID: 15044044 DOI: 10.1016/j.ejphar.2004.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2003] [Revised: 01/26/2004] [Accepted: 02/03/2004] [Indexed: 11/26/2022]
Abstract
In order to develop an in vitro method for detecting residual pertussis toxin activity in acellular pertussis vaccines, the effects of in vivo pertussis toxin treatment on contraction and relaxation properties of isolated mouse trachea and of isolated rat small mesenteric resistance arteries were studied. In vivo pertussis toxin treatment (24 or 72 microg/kg, intraperitoneally (i.p.)) did not affect contraction and relaxation properties of isolated BALB/c or NIH mouse trachea. In vivo pertussis toxin treatment (30 microg/kg, intravenously) significantly reduced noradrenaline- or KCl-induced maximal contraction and reduced sensitivity to noradrenaline in isolated male Wistar rat small mesenteric resistance arteries. However, in vivo pertussis toxin treatment did not affect relaxation properties of isolated rat small mesenteric resistance arteries. These results support the hypothesis that vasoconstriction-regulating mechanisms and not airway constriction mechanisms are involved in pertussis toxin-induced histamine sensitisation. The vasoconstriction-regulating mechanisms may provide a lead for further development of an in vitro method for measuring biologically active pertussis toxin in acellular pertussis vaccines based on mechanisms involved in the histamine sensitisation test.
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Affiliation(s)
- Cornelia E van Meijeren
- National Institute for Public Health and Environment, Laboratory of Toxicology, Pathology and Genetics, P.O. Box 1, 3720 BA Bilthoven, The Netherlands.
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