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López-Dyck E, Andrade-Urzúa F, Elizalde A, Ferrer-Villada T, Dagnino-Acosta A, Huerta M, Osuna-Calleros Z, Rangel-Sandoval C, Sánchez-Pastor E. ACPA and JWH-133 modulate the vascular tone of superior mesenteric arteries through cannabinoid receptors, BK Ca channels, and nitric oxide dependent mechanisms. Pharmacol Rep 2017; 69:1131-1139. [PMID: 29128791 DOI: 10.1016/j.pharep.2017.06.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 05/26/2017] [Accepted: 06/20/2017] [Indexed: 01/25/2023]
Abstract
BACKGROUND Some cannabinoids, a family of compounds derived from Cannabis sativa (marijuana), have previously shown vasodilator effects in several studies, a feature that makes them suitable for the generation of a potential treatment for hypertension. The mechanism underlying this vasodilator effect in arteries is still controversial. In this report, we explored how the synthetic cannabinoids ACPA (CB1-selective agonist) and JWH-133 (CB2-selective agonist) regulate the vascular tone of rat superior mesenteric arteries. METHODS To screen the expression of CB1 (Cannabinoid receptor 1) and CB2 (Cannabinoid receptor 2) receptors in arterial rings or isolated smooth muscle cells obtained from the artery, immunocytochemistry, immunohistochemistry, and confocal microscopy were performed. In addition, the effects on vascular tone induced by the two cannabinoids were tested in isometric tension experiments in rings obtained from superior mesenteric arteries. The participation of voltage and calcium-activated potassium channel of big conductance (BKCa) and the role of nitric oxide (NO) release on the vascular effects induced by ACPA and JWH-133 were tested. RESULTS CB1 and CB2 receptors were highly expressed in the rat superior mesenteric artery, in both smooth muscle and endothelium. The vasodilation effect shown by ACPA was endothelium-dependent through a mechanism involving CB1 receptors, BKCa channel activation, and NO release; meanwhile, the vasodilator effect of JWH-133 was induced by the activation of CB2 receptors located in smooth muscle and by a CB2 receptor-independent mechanism inducing NO release. CONCLUSIONS CB1 and CB2 receptor activation in superior mesenteric artery causes vasorelaxation by mechanisms involving BKCa channels and NO release.
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Affiliation(s)
- Evelyn López-Dyck
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Mexico
| | | | - Alejandro Elizalde
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Mexico
| | - Tania Ferrer-Villada
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Mexico
| | | | - Miguel Huerta
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Mexico
| | - Zyanya Osuna-Calleros
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Mexico
| | | | - Enrique Sánchez-Pastor
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Mexico.
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Modulation of GPCRs by monovalent cations and anions. Naunyn Schmiedebergs Arch Pharmacol 2014; 388:363-80. [DOI: 10.1007/s00210-014-1073-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 11/17/2014] [Indexed: 10/24/2022]
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Brown I, Cascio MG, Rotondo D, Pertwee RG, Heys SD, Wahle KW. Cannabinoids and omega-3/6 endocannabinoids as cell death and anticancer modulators. Prog Lipid Res 2013; 52:80-109. [DOI: 10.1016/j.plipres.2012.10.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 10/05/2012] [Indexed: 01/18/2023]
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Wang Y, Kong Y, Shei GJ, Kang L, Cvijic ME. Development of a cyclic adenosine monophosphate assay for Gi-coupled G protein-coupled receptors by utilizing the endogenous calcitonin activity in Chinese hamster ovary cells. Assay Drug Dev Technol 2011; 9:522-31. [PMID: 21561374 DOI: 10.1089/adt.2010.0361] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Activation of G(i)-coupled G protein-coupled receptor (GPCRs) by their ligands leads to inhibition of adenylyl cyclase (AC) and reduction of cyclic adenosine monophosphate (cAMP) levels in cells. The traditional cAMP assay for G(i)-coupled GPCRs commonly uses forskolin, a nonspecific AC activator, to increase the basal cAMP level in cells to create an assay window for ligand detection. However, there is still a need to develop a nonforskolin-based cAMP assay because of the challenges inherent in titrating the concentration of forskolin to achieve a reliable assay window, along with issues related to the cAMP-independent effects of forskolin. Herein, we describe such an assay by utilizing the endogenous activity of the calcitonin receptor in Chinese hamster ovary (CHO) cells. The calcitonin receptor is a G(s)-coupled GPCR that, when activated by calcitonin, leads to the stimulation of AC and increases cAMP in cells. Thus, we use calcitonin, instead of forskolin, to increase the basal cAMP level in CHO cells to achieve an assay window. We demonstrated that calcitonin peptides robustly increased cAMP accumulation in several CHO cell lines stably expressing well-known G(i)-coupled GPCRs, such as the Dopamine D2 receptor, the Opioid μ receptor, or the Cannabinoid receptor-1. Agonists of these G(i)-coupled GPCRs attenuated calcitonin-induced cAMP production in their receptor stable cell lines. On the other hand, antagonists and/or inverse agonists blocked the effects of their agonists on calcitonin-induced cAMP production. This calcitonin-based cAMP assay has been demonstrated to be sensitive and robust and exhibited acceptable assay windows (signal/noise ratio) and, thus, can be applied to screen for agonists and antagonists/inverse agonists of G(i)-coupled GPCRs in high-throughput screening formats.
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Affiliation(s)
- Yuren Wang
- Metabolic Disease Research, Bristol-Myers Squibb Company, 311 Pennington-Rocky Hill Road, Pennington, NJ 08534, USA.
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Sf9 cells: a versatile model system to investigate the pharmacological properties of G protein-coupled receptors. Pharmacol Ther 2010; 128:387-418. [PMID: 20705094 DOI: 10.1016/j.pharmthera.2010.07.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 07/12/2010] [Indexed: 11/23/2022]
Abstract
The Sf9 cell/baculovirus expression system is widely used for high-level protein expression, often with the purpose of purification. However, proteins may also be functionally expressed in the defined Sf9 cell environment. According to the literature, the pharmacology of G-protein-coupled receptors (GPCRs) functionally reconstituted in Sf9 cells is similar to the receptor properties in mammalian cells. Sf9 cells express both recombinant GPCRs and G-proteins at much higher levels than mammalian cells. Sf9 cells can be grown in suspension culture, providing an inexpensive way of obtaining large protein amounts. Co-infection with various baculoviruses allows free combination of GPCRs with different G-proteins. The absence of constitutively active receptors in Sf9 cells provides an excellent signal-to background ratio in functional assays, allowing the detection of agonist-independent receptor activity and of small ligand-induced signals including partial agonistic and inverse agonistic effects. Insect cell Gα(i)-like proteins mostly do not couple productively to mammalian GPCRs. Thus, unlike in mammalian cells, Sf9 cells do not require pertussis toxin treatment to obtain a Gα(i)-free environment. Co-expression of GPCRs with Gα(i1), Gα(i2), Gα(i3) or Gα(o) in Sf9 cells allows the generation of a selectivity profile for these Gα(i/o)-isoforms. Additionally, GPCR-G-protein combinations can be compared with defined 1:1 stoichiometry by expressing GPCR-Gα fusion proteins. Sf9 cells can also be employed for ligand screening in medicinal chemistry programs, using radioligand binding assays or functional assays, like the steady-state GTPase- or [(35)S]GTPγS binding assay. This review shows that Sf9 cells are a versatile model system to investigate the pharmacological properties of GPCRs.
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Geiger S, Nickl K, Schneider EH, Seifert R, Heilmann J. Establishment of recombinant cannabinoid receptor assays and characterization of several natural and synthetic ligands. Naunyn Schmiedebergs Arch Pharmacol 2010; 382:177-91. [PMID: 20617431 DOI: 10.1007/s00210-010-0534-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 06/21/2010] [Indexed: 11/24/2022]
Abstract
Cannabinoid receptors (CBR) are important drug targets for the treatment of various inflammatory, metabolic and neurological diseases. Therefore, sensitive test systems for the assessment of ligands are needed. In this study, a steady-state GTPase assay for human CBR subtypes 1 and 2 was developed to characterize the pharmacological property of ligands at a very proximal point of the signal transduction cascade. Establishing these in vitro test sytems, we studied cell or tissue membranes heterogenously or endogenously expressing CBR, such as CBR-infected Human Embryonic Kidney (HEK) 293 cells, rat cerebellum and spleen cells. The lack of effects in the GTPase assay and in [(35)S]GTPgammaS binding experiments in these expression system, directed us to use Spodoptera frugiperda (Sf9) cells. Co-expressing CBR, different Galpha-subunits, Gbetagamma heterodimer, and RGS (Regulator of G-protein signaling)-proteins in Sf9 cell membranes greatly improved the sensitivity of the assay, with highest GTPase activation in the CBR + Galpha(i2) + Gbeta(1)gamma(2) + RGS4 system. We examined exogenous and endogenous standard ligands as well as secondary metabolites as Delta(9)-tetrahydrocannabinol (Delta(9)-THC), dodeca-2E,4E-dienoic acid isobutylamide, an alkylamide from Echinacea purpurea, and an E. purpurea hexane extract according their agonistic and antagonistic properties. The suitability of the assay for screening procedures was also proven by detecting the activity of Delta(9)-THC in a matrix of other less active compounds (Delta(9)-THC-free Cannabis sativa extract). In conclusion, we have developed highly sensitive test systems for the analysis of CBR ligands.
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Affiliation(s)
- Sarah Geiger
- Department of Pharmaceutical Biology, Institute of Pharmacy, University of Regensburg, 93053, Regensburg, Germany
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Cudaback E, Marrs W, Moeller T, Stella N. The expression level of CB1 and CB2 receptors determines their efficacy at inducing apoptosis in astrocytomas. PLoS One 2010; 5:e8702. [PMID: 20090845 PMCID: PMC2806825 DOI: 10.1371/journal.pone.0008702] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Accepted: 11/11/2009] [Indexed: 01/22/2023] Open
Abstract
Background Cannabinoids represent unique compounds for treating tumors, including astrocytomas. Whether CB1 and CB2 receptors mediate this therapeutic effect is unclear. Principal Findings We generated astrocytoma subclones that express set levels of CB1 and CB2, and found that cannabinoids induce apoptosis only in cells expressing low levels of receptors that couple to ERK1/2. In contrast, cannabinoids do not induce apoptosis in cells expressing high levels of receptors because these now also couple to the prosurvival signal AKT. Remarkably, cannabinoids applied at high concentration induce apoptosis in all subclones independently of CB1, CB2 and AKT, but still through a mechanism involving ERK1/2. Significance The high expression level of CB1 and CB2 receptors commonly found in malignant astrocytomas precludes the use of cannabinoids as therapeutics, unless AKT is concomitantly inhibited, or cannabinoids are applied at concentrations that bypass CB1 and CB2 receptors, yet still activate ERK1/2.
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Affiliation(s)
- Eiron Cudaback
- Department of Pharmacology, University of Washington, Seattle, Washington, United States of America
| | - William Marrs
- Department of Pharmacology, University of Washington, Seattle, Washington, United States of America
- Graduate Program in Neurobiology and Behavior, University of Washington, Seattle, Washington, United States of America
| | - Thomas Moeller
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
| | - Nephi Stella
- Department of Pharmacology, University of Washington, Seattle, Washington, United States of America
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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Schnell D, Burleigh K, Trick J, Seifert R. No Evidence for Functional Selectivity of Proxyfan at the Human Histamine H3 Receptor Coupled to Defined Gi/Go Protein Heterotrimers. J Pharmacol Exp Ther 2009; 332:996-1005. [DOI: 10.1124/jpet.109.162339] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Schneider EH, Seifert R. Histamine H(4) receptor-RGS fusion proteins expressed in Sf9 insect cells: a sensitive and reliable approach for the functional characterization of histamine H(4) receptor ligands. Biochem Pharmacol 2009; 78:607-16. [PMID: 19464266 DOI: 10.1016/j.bcp.2009.05.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 05/08/2009] [Accepted: 05/11/2009] [Indexed: 11/16/2022]
Abstract
The human histamine H(4) receptor (hH(4)R), co-expressed with Galpha(i2) and Gbeta(1)gamma(2) in Sf9 cells, is highly constitutively active. In the steady-state GTPase assay, the full agonist histamine (HA) induces only a relatively small signal (approximately 20-30%), resulting in a low signal-to background ratio. In order to improve this system for ligand screening purposes, the effects of the regulators of G-protein signaling (RGS) RGS4 and RGS19 (GAIP) were investigated. RGS4 and GAIP were fused to the C-terminus of hH(4)R or co-expressed with non-fused hH(4)R, always combined with Galpha(i2) and Gbeta(1)gamma(2). The non-fused RGS proteins did not significantly increase the relative effect of HA. With the hH(4)R-RGS4 fusion protein the absolute GTPase activities, but not the relative HA-induced signal were increased. Fusion of hH(4)R with GAIP caused a selective increase of the HA signal, resulting in an enhanced signal-to-noise ratio. A detailed characterization of the hH(4)R-GAIP fusion protein (co-expressed with Galpha(i2) and Gbeta(1)gamma(2)) and a comparison with the data obtained for the non-fused hH(4)R (co-expressed with Galpha(i2) and Gbeta(1)gamma(2)) led to the following results: (i) the relative agonist- and inverse agonist-induced signals at hH(4)R-GAIP are markedly increased. (ii) Compared to the wild-type hH(4)R, standard ligands show unaltered potencies and efficacies at hH(4)R-GAIP. (iii) Like hH(4)R, hH(4)R-GAIP shows high and NaCl-resistant constitutive activity. (iv) hH(4)R-GAIP shows the same G-protein selectivity profile as the non-fused hH(4)R. Collectively, hH(4)R-GAIP provides a sensitive test system for the characterization of hH(4)R ligands and can replace the non-fused hH(4)R in steady-state GTPase assays.
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Affiliation(s)
- Erich H Schneider
- University of Regensburg, Department of Pharmacology and Toxicology, Regensburg, Germany.
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