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Boer GE, Hickey SM, Elliott AG, Pfeffer FM. Synthesis of 2-[2-( tert-butoxycarbonyl)-3-(acyl)guanidino]ethylamine salts for convergent introduction of acyl guanidines. NEW J CHEM 2022. [DOI: 10.1039/d2nj01510b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A series of acylguanidines with pre-installed ethylamino linkers are described that can be incorporated into larger structures through amide coupling.
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Affiliation(s)
- Gareth E. Boer
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, 3216, Australia
| | - Shane M. Hickey
- Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5000, Australia
| | - Alysha G. Elliott
- Centre for Superbug Solutions, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Frederick M. Pfeffer
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, 3216, Australia
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2
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Höring C, Seibel U, Tropmann K, Grätz L, Mönnich D, Pitzl S, Bernhardt G, Pockes S, Strasser A. A Dynamic, Split-Luciferase-Based Mini-G Protein Sensor to Functionally Characterize Ligands at All Four Histamine Receptor Subtypes. Int J Mol Sci 2020; 21:ijms21228440. [PMID: 33182741 PMCID: PMC7698210 DOI: 10.3390/ijms21228440] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 11/06/2020] [Accepted: 11/08/2020] [Indexed: 02/06/2023] Open
Abstract
In drug discovery, assays with proximal readout are of great importance to study target-specific effects of potential drug candidates. In the field of G protein-coupled receptors (GPCRs), the determination of GPCR-G protein interactions and G protein activation by means of radiolabeled GTP analogs ([35S]GTPγS, [γ-32P]GTP) has widely been used for this purpose. Since we were repeatedly faced with insufficient quality of radiolabeled nucleotides, there was a requirement to implement a novel proximal functional assay for the routine characterization of putative histamine receptor ligands. We applied the split-NanoLuc to the four histamine receptor subtypes (H1R, H2R, H3R, H4R) and recently engineered minimal G (mini-G) proteins. Using this method, the functional response upon receptor activation was monitored in real-time and the four mini-G sensors were evaluated by investigating selected standard (inverse) agonists and antagonists. All potencies and efficacies of the studied ligands were in concordance with literature data. Further, we demonstrated a significant positive correlation of the signal amplitude and the mini-G protein expression level in the case of the H2R, but not for the H1R or the H3R. The pEC50 values of histamine obtained under different mini-G expression levels were consistent. Moreover, we obtained excellent dynamic ranges (Z’ factor) and the signal spans were improved for all receptor subtypes in comparison to the previously performed [35S]GTPγS binding assay.
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Affiliation(s)
- Carina Höring
- Correspondence: (C.H.); , (A.S.); Tel.: +49-941-943-4748 (C.H.); +49-941-943-4821 (A.S.)
| | | | | | | | | | | | | | | | - Andrea Strasser
- Correspondence: (C.H.); , (A.S.); Tel.: +49-941-943-4748 (C.H.); +49-941-943-4821 (A.S.)
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3
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Bartole E, Littmann T, Tanaka M, Ozawa T, Buschauer A, Bernhardt G. [ 3H]UR-DEBa176: A 2,4-Diaminopyrimidine-Type Radioligand Enabling Binding Studies at the Human, Mouse, and Rat Histamine H 4 Receptors. J Med Chem 2019; 62:8338-8356. [PMID: 31469288 DOI: 10.1021/acs.jmedchem.9b01342] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Differences in sequence homology between human (h), mouse (m), and rat (r) histamine H4 receptors (H4R) cause discrepancies regarding affinities, potencies, and/or efficacies of ligands and therefore compromise translational animal models and the applicability of radioligands. Aiming at a radioligand enabling robust and comparative binding studies at the h/m/rH4Rs, 2,4-diaminopyrimidines were synthesized and pharmacologically investigated. The most notable compounds identified were two (partial) agonists with comparable potencies at the h/m/rH4Rs: UR-DEBa148 (N-neopentyl-4-(1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridin-5-yl)pyrimidin-2-amine bis(2,2,2-trifluoroacetate), 43), the most potent [pEC50 (reporter gene assay) = 9.9/9.6/10.3] compound in the series being slightly G-protein biased and UR-DEBa176 [(R)-4-[3-(dimethylamino)pyrrolidin-1-yl]-N-neopentylpyrimidin-2-amine bis(2,2,2-trifluoroacetate), 46, pEC50 (reporter gene assay) = 8.7/9.0/9.2], a potential "cold" form of a tritiated H4R ligand. After radiolabeling, binding studies with [3H]UR-DEBa176 ([3H]46) at the h/m/rH4Rs revealed comparable Kd values (41/17/22 nM), low nonspecific binding (11-17%, ∼Kd), and fast associations/dissociations (25-30 min) and disclosed [3H]UR-DEBa176 as useful molecular tool to determine h/m/rH4R binding affinities for H4R ligands.
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Affiliation(s)
- Edith Bartole
- Institute of Pharmacy , University of Regensburg , D-93053 Regensburg , Germany
| | - Timo Littmann
- Institute of Pharmacy , University of Regensburg , D-93053 Regensburg , Germany
| | - Miho Tanaka
- Department of Chemistry, School of Science , University of Tokyo , 7-3-1 Bunkyo-ku , Hongo , Tokyo 113-0033 , Japan
| | - Takeaki Ozawa
- Department of Chemistry, School of Science , University of Tokyo , 7-3-1 Bunkyo-ku , Hongo , Tokyo 113-0033 , Japan
| | - Armin Buschauer
- Institute of Pharmacy , University of Regensburg , D-93053 Regensburg , Germany
| | - Günther Bernhardt
- Institute of Pharmacy , University of Regensburg , D-93053 Regensburg , Germany
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Pockes S, Wifling D, Buschauer A, Elz S. Structure-Activity Relationship of Hetarylpropylguanidines Aiming at the Development of Selective Histamine Receptor Ligands †. ChemistryOpen 2019; 8:285-297. [PMID: 30886786 PMCID: PMC6401531 DOI: 10.1002/open.201900011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/08/2019] [Indexed: 11/05/2022] Open
Abstract
New classes of alkylated hetarylpropylguanidines with different functionality and variation in spacer length were synthesized to determine their behavior at the four histamine receptor (H1R, H2R, H3R, H4R) subtypes. Alkylated guanidines with different terminal functional groups and varied basicity, like amine, guanidine and urea were developed, based on the lead structure SK&F 91486 (2). Furthermore, heteroatomic exchange at the guanidine structure of 2 led to simple analogues of the lead compound. Radioassays at all histamine receptor subtypes were accomplished, as well as organ bath studies at the guinea pig (gp) ileum (gpH1R) and right atrium (gpH2R). Ligands with terminal functionalization led to, partially, highly affine and potent structures (two digit nanomolar), which showed up a bad selectivity profile within the histamine receptor family. While the benzoylurea derivative 144 demonstrated a preference towards the human (h) H3R, S-methylisothiourea analogue 143 obtained high affinity at the hH4R (pKi=8.14) with moderate selectivity. The molecular basis of the latter finding was supported by computational studies.
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Affiliation(s)
- Steffen Pockes
- Institute of Pharmacy, Faculty of Chemistry and PharmacyUniversity of RegensburgUniversitätsstraße 31D-93053RegensburgGermany
| | - David Wifling
- Institute of Pharmacy, Faculty of Chemistry and PharmacyUniversity of RegensburgUniversitätsstraße 31D-93053RegensburgGermany
| | - Armin Buschauer
- Institute of Pharmacy, Faculty of Chemistry and PharmacyUniversity of RegensburgUniversitätsstraße 31D-93053RegensburgGermany
| | - Sigurd Elz
- Institute of Pharmacy, Faculty of Chemistry and PharmacyUniversity of RegensburgUniversitätsstraße 31D-93053RegensburgGermany
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5
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Liu S, Wang R, Zhu B, Guan W, Liang F. Photo- and dioxygen-enabled radical C(sp3)–N(sp2) cross-coupling between guanidines and perfluoroalkyl iodides. Org Biomol Chem 2019; 17:8695-8700. [DOI: 10.1039/c9ob01520e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The utilization of visible light and dioxygen (air) as green and sustainable mediators in photocatalyzed synthetic chemistry is demonstrated.
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Affiliation(s)
- Shulin Liu
- College of Chemistry
- Liaoning University
- Shenyang 110036
- China
| | - Rui Wang
- Institute of Petrochemical Technology
- Jilin Institute of Chemical Technology
- Jilin 132022
- China
| | - Bo Zhu
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- China
| | - Wei Guan
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- China
| | - Fushun Liang
- College of Chemistry
- Liaoning University
- Shenyang 110036
- China
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6
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Pockes S, Wifling D, Keller M, Buschauer A, Elz S. Highly Potent, Stable, and Selective Dimeric Hetarylpropylguanidine-Type Histamine H 2 Receptor Agonists. ACS OMEGA 2018; 3:2865-2882. [PMID: 30221224 PMCID: PMC6130797 DOI: 10.1021/acsomega.8b00128] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 02/13/2018] [Indexed: 06/08/2023]
Abstract
On the basis of the long-known prototypic pharmacophore 3-(1H-imidazol-4-yl)propylguanidine (SK&F 91486, 2), monomeric, homodimeric, and heterodimeric bisalkylguanidine-type histamine H2 receptor (H2R) agonists with various alkyl spacers were synthesized. Aiming at increased H2R selectivity of the ligands, the imidazol-4-yl moiety was replaced by imidazol-1-yl, 2-aminothiazol-5-yl or 2-amino-4-methylthiazol-5-yl according to a bioisosteric approach. All compounds turned out to be partial or full agonists at the h/gp/rH2R. The most potent analogue, the thiazole-type heterodimeric ligand 63 (UR-Po461), was a partial agonist (Emax = 88%) and 250 times more potent than histamine (pEC50: 8.56 vs 6.16, gpH2R, atrium). The homodimeric structures 56 (UR-Po395) and 58 (UR-Po448) exhibited the highest hH2R affinities (pKi: 7.47, 7.33) in binding studies. Dimeric amino(methyl)thiazole derivatives, such as 58, generated an increased hH2R selectivity compared to the monomeric analogues, e.g., 139 (UR-Po444). Although monomeric ligands showed up lower affinities and potencies at the H2R, compounds with a short alkylic side chain like 129 (UR-Po194) proved to be highly affine hH4R ligands.
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Affiliation(s)
- Steffen Pockes
- E-mail: . Phone: (+49)941-9434814. Fax: (+49)941-9434809
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Hattori Y, Seifert R. Pharmacological Characterization of Human Histamine Receptors and Histamine Receptor Mutants in the Sf9 Cell Expression System. Handb Exp Pharmacol 2017; 241:63-118. [PMID: 28233175 PMCID: PMC7120522 DOI: 10.1007/164_2016_124] [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] [Indexed: 01/12/2023]
Abstract
A large problem of histamine receptor research is data heterogeneity. Various experimental approaches, the complex signaling pathways of mammalian cells, and the use of different species orthologues render it difficult to compare and interpret the published results. Thus, the four human histamine receptor subtypes were analyzed side-by-side in the Sf9 insect cell expression system, using radioligand binding assays as well as functional readouts proximal to the receptor activation event (steady-state GTPase assays and [35S]GTPγS assays). The human H1R was co-expressed with the regulators of G protein signaling RGS4 or GAIP, which unmasked a productive interaction between hH1R and insect cell Gαq. By contrast, functional expression of the hH2R required the generation of an hH2R-Gsα fusion protein to ensure close proximity of G protein and receptor. Fusion of hH2R to the long (GsαL) or short (GsαS) splice variant of Gαs resulted in comparable constitutive hH2R activity, although both G protein variants show different GDP affinities. Medicinal chemistry studies revealed profound species differences between hH1R/hH2R and their guinea pig orthologues gpH1R/gpH2R. The causes for these differences were analyzed by molecular modeling in combination with mutational studies. Co-expression of the hH3R with Gαi1, Gαi2, Gαi3, and Gαi/o in Sf9 cells revealed high constitutive activity and comparable interaction efficiency with all G protein isoforms. A comparison of various cations (Li+, Na+, K+) and anions (Cl-, Br-, I-) revealed that anions with large radii most efficiently stabilize the inactive hH3R state. Potential sodium binding sites in the hH3R protein were analyzed by expressing specific hH3R mutants in Sf9 cells. In contrast to the hH3R, the hH4R preferentially couples to co-expressed Gαi2 in Sf9 cells. Its high constitutive activity is resistant to NaCl or GTPγS. The hH4R shows structural instability and adopts a G protein-independent high-affinity state. A detailed characterization of affinity and activity of a series of hH4R antagonists/inverse agonists allowed first conclusions about structure/activity relationships for inverse agonists at hH4R. In summary, the Sf9 cell system permitted a successful side-by-side comparison of all four human histamine receptor subtypes. This chapter summarizes the results of pharmacological as well as medicinal chemistry/molecular modeling approaches and demonstrates that these data are not only important for a deeper understanding of HxR pharmacology, but also have significant implications for the molecular pharmacology of GPCRs in general.
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Affiliation(s)
- Yuichi Hattori
- Department of Molecular and Medical Pharmacology, Graduate School of Medical and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Roland Seifert
- Institute of Pharmacology, Medical School of Hannover, Hannover, Germany
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8
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Pontiki E, Hadjipavlou-Litina D. QSAR models on H4 receptor antagonists associated with inflammation and anaphylaxis. J Biomol Struct Dyn 2016; 35:968-1005. [DOI: 10.1080/07391102.2016.1166986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Eleni Pontiki
- Department of Pharmaceutical Chemistry, School of Pharmacy, Aristotle University of Thessaloniki , Thessaloniki 54124, Greece
| | - Dimitra Hadjipavlou-Litina
- Department of Pharmaceutical Chemistry, School of Pharmacy, Aristotle University of Thessaloniki , Thessaloniki 54124, Greece
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Geyer R, Nordemann U, Strasser A, Wittmann HJ, Buschauer A. Conformational Restriction and Enantioseparation Increase Potency and Selectivity of Cyanoguanidine-Type Histamine H4 Receptor Agonists. J Med Chem 2016; 59:3452-70. [PMID: 27007611 DOI: 10.1021/acs.jmedchem.6b00120] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
2-Cyano-1-[4-(1H-imidazol-4-yl)butyl]-3-[2-(phenylsulfanyl)ethyl]guanidine (UR-PI376, 1) is a potent and selective agonist of the human histamine H4 receptor (hH4R). To gain information on the active conformation, we synthesized analogues of 1 with a cyclopentane-1,3-diyl linker. Affinities and functional activities were determined at recombinant hHxR (x: 1-4) subtypes on Sf9 cell membranes (radioligand binding, [(35)S]GTPγS, or GTPase assays) and in part in luciferase assays on human or mouse H4R (HEK-293 cells). The most potent H4R agonists among 14 racemates were separated by chiral HPLC, yielding eight enantiomerically pure compounds. Configurations were assigned based on X-ray structures of intermediates and a stereocontrolled synthetic pathway. (+)-2-Cyano-1-{[trans-(1S,3S)-3-(1H-imidazol-4-yl)cyclopentyl]methyl}-3-[2-(phenylsulfanyl)ethyl]guanidine ((1S,3S)-UR-RG98, 39a) was the most potent H4R agonist in this series (EC50 11 nM; H4R vs H3R, >100-fold selectivity; H1R, H2R, negligible activities), whereas the optical antipode proved to be an H4R antagonist ([(35)S]GTPγS assay). MD simulations confirmed differential stabilization of the active and inactive H4R state by the enantiomers.
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Affiliation(s)
- Roland Geyer
- Institute of Pharmacy, Pharmaceutical/Medicinal Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg , Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Uwe Nordemann
- Institute of Pharmacy, Pharmaceutical/Medicinal Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg , Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Andrea Strasser
- Institute of Pharmacy, Pharmaceutical/Medicinal Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg , Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Hans-Joachim Wittmann
- Institute of Pharmacy, Pharmaceutical/Medicinal Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg , Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Armin Buschauer
- Institute of Pharmacy, Pharmaceutical/Medicinal Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg , Universitätsstraße 31, D-93053 Regensburg, Germany
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Lee YP, Kuo TF, Lee SS. Identification of the metabolites of TCM prescription Sinisan, found in miniature pig urine via intragastric administration. J Pharm Biomed Anal 2015; 111:311-9. [DOI: 10.1016/j.jpba.2015.04.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Revised: 04/04/2015] [Accepted: 04/06/2015] [Indexed: 02/09/2023]
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11
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Wifling D, Löffel K, Nordemann U, Strasser A, Bernhardt G, Dove S, Seifert R, Buschauer A. Molecular determinants for the high constitutive activity of the human histamine H4 receptor: functional studies on orthologues and mutants. Br J Pharmacol 2015; 172:785-98. [PMID: 24903527 PMCID: PMC4301689 DOI: 10.1111/bph.12801] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 05/19/2014] [Accepted: 05/27/2014] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE Some histamine H4 receptor ligands act as inverse agonists at the human H4 receptor (hH4 R), a receptor with exceptionally high constitutive activity, but as neutral antagonists or partial agonists at the constitutively inactive mouse H4 receptor (mH4 R) and rat H4 receptor (rH4 R). To study molecular determinants of constitutive activity, H4 receptor reciprocal mutants were constructed: single mutants: hH4 R-F169V, mH4 R-V171F, hH4 R-S179A, hH4 R-S179M; double mutants: hH4 R-F169V+S179A, hH4 R-F169V+S179M and mH4 R-V171F+M181S. EXPERIMENTAL APPROACH Site-directed mutagenesis with pVL1392 plasmids containing hH4 or mH4 receptors were performed. Wild-type or mutant receptors were co-expressed with Gαi2 and Gβ1 γ2 in Sf9 cells. Membranes were studied in saturation and competition binding assays ([(3) H]-histamine), and in functional [(35) S]-GTPγS assays with inverse, partial and full agonists of the hH4 receptor. KEY RESULTS Constitutive activity decreased from the hH4 receptor via the hH4 R-F169V mutant to the hH4 R-F169V+S179A and hH4 R-F169V+S179M double mutants. F169 alone or in concert with S179 plays a major role in stabilizing a ligand-free active state of the hH4 receptor. Partial inverse hH4 receptor agonists like JNJ7777120 behaved as neutral antagonists or partial agonists at species orthologues with lower or no constitutive activity. Some partial and full hH4 receptor agonists showed decreased maximal effects and potencies at hH4 R-F169V and double mutants. However, the mutation of S179 in the hH4 receptor to M as in mH4 receptor or A as in rH4 receptor did not significantly reduce constitutive activity. CONCLUSIONS AND IMPLICATIONS F169 and S179 are key amino acids for the high constitutive activity of hH4 receptors and may also be of relevance for other constitutively active GPCRs. LINKED ARTICLES This article is part of a themed issue on Histamine Pharmacology Update published in volume 170 issue 1. To view the other articles in this issue visit http://onlinelibrary.wiley.com/doi/10.1111/bph.2013.170.issue-1/issuetoc.
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Affiliation(s)
- D Wifling
- Institute of Pharmacy, University of Regensburg, Regensburg, Germany
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Wifling D, Bernhardt G, Dove S, Buschauer A. The extracellular loop 2 (ECL2) of the human histamine H4 receptor substantially contributes to ligand binding and constitutive activity. PLoS One 2015; 10:e0117185. [PMID: 25629160 PMCID: PMC4309601 DOI: 10.1371/journal.pone.0117185] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 12/21/2014] [Indexed: 11/25/2022] Open
Abstract
In contrast to the corresponding mouse and rat orthologs, the human histamine H4 receptor (hH4R) shows extraordinarily high constitutive activity. In the extracellular loop (ECL), replacement of F169 by V as in the mouse H4R significantly reduced constitutive activity. Stabilization of the inactive state was even more pronounced for a double mutant, in which, in addition to F169V, S179 in the ligand binding site was replaced by M. To study the role of the FF motif in ECL2, we generated the hH4R-F168A mutant. The receptor was co-expressed in Sf9 insect cells with the G-protein subunits Gαi2 and Gβ1γ2, and the membranes were studied in [3H]histamine binding and functional [35S]GTPγS assays. The potency of various ligands at the hH4R-F168A mutant decreased compared to the wild-type hH4R, for example by 30- and more than 100-fold in case of the H4R agonist UR-PI376 and histamine, respectively. The high constitutive activity of the hH4R was completely lost in the hH4R-F168A mutant, as reflected by neutral antagonism of thioperamide, a full inverse agonist at the wild-type hH4R. By analogy, JNJ7777120 was a partial inverse agonist at the hH4R, but a partial agonist at the hH4R-F168A mutant, again demonstrating the decrease in constitutive activity due to F168A mutation. Thus, F168 was proven to play a key role not only in ligand binding and potency, but also in the high constitutive activity of the hH4R.
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Affiliation(s)
- David Wifling
- Institute of Pharmacy, Pharmaceutical/Medicinal Chemistry II, University of Regensburg, Regensburg, Germany
| | - Günther Bernhardt
- Institute of Pharmacy, Pharmaceutical/Medicinal Chemistry II, University of Regensburg, Regensburg, Germany
| | - Stefan Dove
- Institute of Pharmacy, Pharmaceutical/Medicinal Chemistry II, University of Regensburg, Regensburg, Germany
| | - Armin Buschauer
- Institute of Pharmacy, Pharmaceutical/Medicinal Chemistry II, University of Regensburg, Regensburg, Germany
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Dimeric carbamoylguanidine-type histamine H2 receptor ligands: A new class of potent and selective agonists. Bioorg Med Chem 2015; 23:3957-69. [PMID: 25639885 DOI: 10.1016/j.bmc.2015.01.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 12/21/2014] [Accepted: 01/07/2015] [Indexed: 11/23/2022]
Abstract
The bioisosteric replacement of the acylguanidine moieties in dimeric histamine H2 receptor (H2R) agonists by carbamoylguanidine groups resulted in compounds with retained potencies and intrinsic activities, but considerably improved stability against hydrolytic cleavage. These compounds achieved up to 2500 times the potency of histamine when studied in [(35)S]GTPγS assays on recombinant human and guinea pig H2R. Unlike 3-(imidazol-4-yl)propyl substituted carbamoylguanidines, the corresponding 2-amino-4-methylthiazoles revealed selectivity over histamine receptor subtypes H1R, H3R and H4R in radioligand competition binding studies. H2R binding studies with three fluorescent compounds and one tritium-labeled ligand, synthesized from a chain-branched precursor, failed due to pronounced cellular accumulation and high non-specific binding. However, the dimeric H2R agonists proved to be useful pharmacological tools for functional studies on native cells, as demonstrated for selected compounds by cAMP accumulation and inhibition of fMLP-stimulated generation of reactive oxygen species in human monocytes.
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Corrêa MF, dos Santos Fernandes JP. Histamine H4 receptor ligands: future applications and state of art. Chem Biol Drug Des 2014; 85:461-80. [PMID: 25228262 DOI: 10.1111/cbdd.12431] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Histamine is a chemical transmitter found practically in whole organism and exerts its effects through the interaction with H1 to H4 histaminergic receptors. Specifically, H4 receptors are found mainly in immune cells and blood-forming tissues, thus are involved in inflammatory and immune processes, as well as some actions in central nervous system. Therefore, H4 receptor ligands can have applications in the treatment of chronic inflammatory and immune diseases and may be novel therapeutic option in these conditions. Several H4 receptor ligands have been described from early 2000's until nowadays, being imidazole, indolecarboxamide, 2-aminopyrimidine, quinazoline, and quinoxaline scaffolds the most explored and discussed in this review. Moreover, several studies of molecular modeling using homology models of H4 receptor and QSAR data of the ligands are summarized. The increasing and promising therapeutic applications are leading these compounds to clinical trials, which probably will be part of the next generation of blockbuster drugs.
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Affiliation(s)
- Michelle Fidelis Corrêa
- Departamento de Ciências Exatas e da Terra, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, UNIFESP, Diadema, Brazil
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15
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Geyer R, Igel P, Kaske M, Elz S, Buschauer A. Synthesis, SAR and selectivity of 2-acyl- and 2-cyano-1-hetarylalkyl-guanidines at the four histamine receptor subtypes: a bioisosteric approach. MEDCHEMCOMM 2014. [DOI: 10.1039/c3md00245d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Rauf MK, Imtiaz-ud-Din, Badshah A. Novel approaches to screening guanidine derivatives. Expert Opin Drug Discov 2013; 9:39-53. [PMID: 24261559 DOI: 10.1517/17460441.2013.857308] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Compounds containing guanidine moiety, originating both from natural and synthetic sources, have found potential applications in both synthetic and medicinal chemistry. Indeed, guanidine functionality can be found in many natural and pharmaceutical products as well as in cosmetic ingredients produced by synthetic methods. AREAS COVERED This review covers the latest developments in the research undertaken for the therapeutic application of newly synthesized guanidine derivatives including: small peptides and peptidomimetics. This article encompasses the selected literature published in the last three decades with a focus on the novel approaches for screening of lead drug candidates with their pharmacological action. EXPERT OPINION Guanidines, as they are both organically based and also hydrophilic in nature, have undergone a mammoth amount of screening and testing to discover promising lead structures with a CN3 core, appropriate for potential future drug development. The compounds have the potential to be neurodegenerative therapeutic options, as well as: anti-inflammatory, anti-protozoal, anti-HIV, chemotherapeutic, anti-diabetic agents and so on. It is true that guanidine-based compounds of natural sources also, like synthetic and virtually designed drugs, have been of significant interest and have the potential to be useful therapeutic options in the future. As for now, however, there is not sufficient data to support their use in a number of the suggested areas, and further studies are required.
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17
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Nordemann U, Wifling D, Schnell D, Bernhardt G, Stark H, Seifert R, Buschauer A. Luciferase reporter gene assay on human, murine and rat histamine H4 receptor orthologs: correlations and discrepancies between distal and proximal readouts. PLoS One 2013; 8:e73961. [PMID: 24023919 PMCID: PMC3759464 DOI: 10.1371/journal.pone.0073961] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 07/24/2013] [Indexed: 11/18/2022] Open
Abstract
The investigation of the (patho)physiological role of the histamine H4 receptor (H4R) and its validation as a possible drug target in translational animal models are compromised by distinct species-dependent discrepancies regarding potencies and receptor subtype selectivities of the pharmacological tools. Such differences were extremely pronounced in case of proximal readouts, e. g. [(32)P]GTPase or [(35)S]GTPγS binding assays. To improve the predictability of in vitro investigations, the aim of this study was to establish a reporter gene assay for human, murine and rat H4Rs, using bioluminescence as a more distal readout. For this purpose a cAMP responsive element (CRE) controlled luciferase reporter gene assay was established in HEK293T cells, stably expressing the human (h), the mouse (m) or the rat (r) H4R. The potencies and efficacies of 23 selected ligands (agonists, inverse agonists and antagonists) were determined and compared with the results obtained from proximal readouts. The potencies of the examined ligands at the human H4R were consistent with reported data from [(32)P]GTPase or [(35)S]GTPγS binding assays, despite a tendency toward increased intrinsic efficacies of partial agonists. The differences in potencies of individual agonists at the three H4R orthologs were generally less pronounced compared to more proximal readouts. In conclusion, the established reporter gene assay is highly sensitive and reliable. Regarding discrepancies compared to data from functional assays such as [(32)P]GTPase and [(35)S]GTPγS binding, the readout may reflect multifactorial causes downstream from G-protein activation, e.g. activation/amplification of or cross-talk between different signaling pathways.
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Affiliation(s)
- Uwe Nordemann
- Institute of Pharmacy, University of Regensburg, Regensburg, Germany
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18
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Seifert R, Strasser A, Schneider EH, Neumann D, Dove S, Buschauer A. Molecular and cellular analysis of human histamine receptor subtypes. Trends Pharmacol Sci 2013; 34:33-58. [PMID: 23254267 PMCID: PMC3869951 DOI: 10.1016/j.tips.2012.11.001] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 11/03/2012] [Accepted: 11/05/2012] [Indexed: 01/08/2023]
Abstract
The human histamine receptors hH(1)R and hH(2)R constitute important drug targets, and hH(3)R and hH(4)R have substantial potential in this area. Considering the species-specificity of pharmacology of H(x)R orthologs, it is important to analyze hH(x)Rs. Here, we summarize current knowledge of hH(x)Rs endogenously expressed in human cells and hH(x)Rs recombinantly expressed in mammalian and insect cells. We present the advantages and disadvantages of the various systems. We also discuss problems associated with the use of hH(x)R antibodies, an issue of general relevance for G-protein-coupled receptors (GPCRs). There is much greater overlap in activity of 'selective' ligands for other hH(x)Rs than the cognate receptor subtype than generally appreciated. Studies with native and recombinant systems support the concept of ligand-specific receptor conformations, encompassing agonists and antagonists. It is emerging that for characterization of hH(x)R ligands, one cannot rely on a single test system and a single parameter. Rather, multiple systems and parameters have to be studied. Although such studies are time-consuming and expensive, ultimately, they will increase drug safety and efficacy.
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Affiliation(s)
- Roland Seifert
- Institute of Pharmacology, Medical School of Hannover, Hannover, Germany.
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Shao J, Chen W, Giulianotti MA, Houghten RA, Yu Y. Palladium-catalyzed C-H functionalization using guanidine as a directing group: ortho arylation and olefination of arylguanidines. Org Lett 2012; 14:5452-5. [PMID: 23095022 PMCID: PMC3786205 DOI: 10.1021/ol302533w] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Palladium-catalyzed C-H functionalization using guanidine as the directing group was achieved under mild reaction conditions. Various guanidine derivatives were produced in moderate to good yields by using simple unactivated arenes or ethyl acrylate as the source of arylation or olefination, respectively.
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Affiliation(s)
- Jiaan Shao
- Institute of Materia Medica, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Wenteng Chen
- Institute of Materia Medica, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Marc A. Giulianotti
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St Lucie, FL 34987
| | - Richard A. Houghten
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St Lucie, FL 34987
| | - Yongping Yu
- Institute of Materia Medica, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, P. R. China
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St Lucie, FL 34987
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20
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Nijmeijer S, Vischer HF, Rudebeck AF, Fleurbaaij F, Falck D, Leurs R, Niessen WMA, Kool J. Development of a profiling strategy for metabolic mixtures by combining chromatography and mass spectrometry with cell-based GPCR signaling. ACTA ACUST UNITED AC 2012; 17:1329-38. [PMID: 22740245 DOI: 10.1177/1087057112451922] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this study, we developed an in-line methodology that combines analytical with pharmacological techniques to characterize metabolites of human histamine H(4) receptor (hH(4)R) ligands. Liquid chromatographic separation of metabolic mixtures is coupled to high-resolution fractionation into 96- or 384-well plates and directly followed by a cell-based reporter gene assay to measure receptor signaling. The complete methodology was designed, optimized, validated, and ultimately miniaturized into a high-density well plate format. Finally, the methodology was demonstrated in a metabolic profiling setting for three hH(4)R lead compounds and the drug clozapine. This new methodology comprises integrated analytical separations, mass spectrometry, and a cell-based signal transduction-driven reporter gene assay that enables the implementation of comprehensive metabolic profiling earlier in the drug discovery process.
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Affiliation(s)
- Saskia Nijmeijer
- Medicinal Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Sciences, VU University, Amsterdam, The Netherlands
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21
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Kiss R, Keserű GM. Histamine H4 receptor ligands and their potential therapeutic applications: an update. Expert Opin Ther Pat 2012; 22:205-21. [PMID: 22385042 DOI: 10.1517/13543776.2012.665447] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Several studies underlined the critical role of histamine H4 receptor (H4R) in inflammation, thus H4 modulators have been suggested as promising drug candidates in inflammatory diseases. First H4 ligands typically have indole or amino-pyrimidine scaffolds. During the last few years, however, serious efforts have been made to identify novel H4 chemotypes with improved pharmacodynamic and pharmacokinetic properties. AREAS COVERED Areas covered in this review include an overview on H4 ligands published in scientific papers, as well as in patent applications between 2009 and 2011. Recently discovered scaffolds possessing significant H4 activity were analyzed and their therapeutic potential was reviewed. EXPERT OPINION Recent results from the scientific literature and novel patent applications reinforce the major role of H4R in inflammatory diseases such as pruritus, asthma, inflammatory pain and allergic rhinitis. Novel studies suggest further indications of H4 modulators in cancer, neuropathic pain, vestibular disorders and type 2 diabetes. The number of active H4 chemotypes was increased significantly. The first H4 antagonist entered to clinics and the results from a proof-of-concept Phase II clinical study is expected to be disclosed soon.
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Affiliation(s)
- Róbert Kiss
- mcule.com Ltd., Vendel u. 15-17, H-1096, Budapest, Hungary
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22
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Birnkammer T, Spickenreither A, Brunskole I, Lopuch M, Kagermeier N, Bernhardt G, Dove S, Seifert R, Elz S, Buschauer A. The Bivalent Ligand Approach Leads to Highly Potent and Selective Acylguanidine-Type Histamine H2 Receptor Agonists. J Med Chem 2012; 55:1147-60. [DOI: 10.1021/jm201128q] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Tobias Birnkammer
- Department of Pharmaceutical/Medicinal
Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053
Regensburg, Germany
| | - Anja Spickenreither
- Department of Pharmaceutical/Medicinal
Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053
Regensburg, Germany
| | - Irena Brunskole
- Department of Pharmaceutical/Medicinal
Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053
Regensburg, Germany
| | - Miroslaw Lopuch
- Department of Pharmaceutical/Medicinal
Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053
Regensburg, Germany
| | - Nicole Kagermeier
- Department of Pharmaceutical/Medicinal
Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053
Regensburg, Germany
| | - Günther Bernhardt
- Department of Pharmaceutical/Medicinal
Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053
Regensburg, Germany
| | - Stefan Dove
- Department of Pharmaceutical/Medicinal
Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053
Regensburg, Germany
| | - Roland Seifert
- Institute
of Pharmacology, Medical School of Hannover, D-30625 Hannover, Germany
| | - Sigurd Elz
- Department of Pharmaceutical/Medicinal
Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053
Regensburg, Germany
| | - Armin Buschauer
- Department of Pharmaceutical/Medicinal
Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053
Regensburg, Germany
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23
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Geyer R, Buschauer A. Synthesis and histamine H(3) and H(4) receptor activity of conformationally restricted cyanoguanidines related to UR-PI376. Arch Pharm (Weinheim) 2011; 344:775-85. [PMID: 21987304 DOI: 10.1002/ardp.201100144] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 05/09/2011] [Accepted: 05/13/2011] [Indexed: 11/11/2022]
Abstract
Recently, we identified highly potent agonists of the human histamine H(4) receptor (hH(4) R) among a series of imidazolylbutylcyanoguanidines. Aiming at improved selectivity for the hH(4) R relative to the H(3) receptor (hH(3) R), the flexible tetramethylene linker connecting imidazole ring and cyanoguanidine group was replaced by conformationally restricted carbocycles. Introduction of a para- or a meta-phenylene spacer yielded only very weakly active compounds at both hH(3) R and hH(4) R (investigated in [(35) S]GTPγS binding assays using Sf9 insect cell membranes expressing hH(x) R subtypes). By contrast, the incorporation of a more flexible cyclohexane-1,4-diyl linker resulted in EC(50) or K(B) values ≥110 nM at hH(4) R and hH(3) R. Quality of action, potency and receptor subtype selectivity of the investigated compounds depend on the stereochemistry: Cis-configured diastereomers prefer the hH(4) R and are partial agonists, whereas trans-isomers are antagonists at the hH(4) R. At the hH(3) R the trans-diastereomers are superior to the cis-isomers by a factor of 10. The results on imidazolylcycloalkylcyanoguanidines suggest that variation of ring size and optimization of the stereochemistry may be useful to increase the potency and selectivity of hH(4) R agonists relative to the hH(3) R.
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Affiliation(s)
- Roland Geyer
- Department of Pharmaceutical/Medicinal Chemistry II, University of Regensburg, Germany
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24
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Jakopin Ž, Corsini E, Gobec M, Mlinarič-Raščan I, Dolenc MS. Design, synthesis and biological evaluation of novel desmuramyldipeptide analogs. Eur J Med Chem 2011; 46:3762-77. [DOI: 10.1016/j.ejmech.2011.05.042] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 05/14/2011] [Accepted: 05/17/2011] [Indexed: 12/20/2022]
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25
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Affiliation(s)
- Charles M. Marson
- Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H OAJ, United Kingdom
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26
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Wittmann HJ, Elz S, Seifert R, Straßer A. N α-Methylated phenylhistamines exhibit affinity to the hH4R—a pharmacological and molecular modelling study. Naunyn Schmiedebergs Arch Pharmacol 2011; 384:287-99. [DOI: 10.1007/s00210-011-0671-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 07/08/2011] [Indexed: 01/08/2023]
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27
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Pluym N, Brennauer A, Keller M, Ziemek R, Pop N, Bernhardt G, Buschauer A. Application of the Guanidine-Acylguanidine Bioisosteric Approach to Argininamide-Type NPY Y2 Receptor Antagonists. ChemMedChem 2011; 6:1727-38. [DOI: 10.1002/cmdc.201100241] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Indexed: 11/06/2022]
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28
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N-Alkenyl and cycloalkyl carbamates as dual acting histamine H3 and H4 receptor ligands. Bioorg Med Chem 2011; 19:2850-8. [DOI: 10.1016/j.bmc.2011.03.046] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 03/10/2011] [Accepted: 03/18/2011] [Indexed: 11/19/2022]
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29
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Receptor-specific functional efficacies of alkyl imidazoles as dual histamine H3/H4 receptor ligands. Eur J Pharmacol 2011; 654:200-8. [DOI: 10.1016/j.ejphar.2010.12.033] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 11/18/2010] [Accepted: 12/15/2010] [Indexed: 11/23/2022]
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30
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Schnell D, Brunskole I, Ladova K, Schneider EH, Igel P, Dove S, Buschauer A, Seifert R. Expression and functional properties of canine, rat, and murine histamine H₄ receptors in Sf9 insect cells. Naunyn Schmiedebergs Arch Pharmacol 2011; 383:457-70. [PMID: 21359967 DOI: 10.1007/s00210-011-0612-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 12/13/2010] [Indexed: 01/14/2023]
Abstract
The histamine H₄ receptor (H₄R) is expressed on cells of the immune system including eosinophils, dendritic cells, and T cells and plays an important role in the pathogenesis of bronchial asthma, atopic dermatitis, and pruritus. Analysis of the H₄R in these diseases depends on the use of animal models. However, there are substantial pharmacological differences between various H₄R species orthologs. The purpose of this study was to analyze the pharmacological properties of canine, rat, and murine H₄R in comparison to human H₄R expressed in Sf9 insect cells. Only hH₄R and cH₄R exhibited a sufficiently high [³H]histamine affinity for radioligand binding studies. Generally, cH₄R exhibited lower ligand-affinities than hH₄R. Similarly, in high-affinity GTPase studies, ligands were more potent at hH₄R than at other H₄R species orthologs. Unlike the other H₄R species orthologs, hH₄R exhibited high agonist-independent (constitutive) activity. Most strikingly, the prototypical H₄R antagonist (1-[(5-chloro-1H-indol-2-yl)carbonyl]-4-methylpiperazine) (JNJ7777120) exhibited partial agonistic activity at cH₄R, rH₄R, and mH₄R, whereas at hH₄R, JNJ7777120 was a partial inverse agonist. H₄R agonists from the class of N ( G )-acylated imidazolylpropylguanidines and cyanoguanidines exhibited substantial differences in terms of affinity, potency, and efficacy among H₄R species orthologs, too. The species-dependent pharmacological profiles are not due to the highly variable amino acid sequence position 341. Finally, H₄R species orthologs differ from each other in terms of regulation by NaCl. Collectively, there are profound pharmacological differences between H₄R species orthologs. Most importantly, caution must be exerted when interpreting pharmacological effects of "the prototypical H₄R antagonist" JNJ7777120 as H₄R antagonism.
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Affiliation(s)
- David Schnell
- Department of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany
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31
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Wijtmans M, de Graaf C, de Kloe G, Istyastono EP, Smit J, Lim H, Boonnak R, Nijmeijer S, Smits RA, Jongejan A, Zuiderveld O, de Esch IJP, Leurs R. Triazole ligands reveal distinct molecular features that induce histamine H4 receptor affinity and subtly govern H4/H3 subtype selectivity. J Med Chem 2011; 54:1693-703. [PMID: 21348462 DOI: 10.1021/jm1013488] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The histamine H(3) (H(3)R) and H(4) (H(4)R) receptors attract considerable interest from the medicinal chemistry community. Given their relatively high homology yet widely differing therapeutic promises, ligand selectivity for the two receptors is crucial. We interrogated H(4)R/H(3)R selectivities using ligands with a [1,2,3]triazole core. Cu(I)-assisted "click chemistry" was used to assemble diverse [1,2,3]triazole compounds (6a-w and 7a-f), many containing a peripheral imidazole group. The imidazole ring posed some problems in the click chemistry putatively due to Cu(II) coordination, but Boc protection of the imidazole and removal of oxygen from the reaction mixture provided effective strategies. Pharmacological studies revealed two monosubstituted imidazoles (6h,p) with <10 nM H(4)R affinities and >10-fold H(4)R/H(3)R selectivity. Both compounds possess a cycloalkylmethyl group and appear to target a lipophilic pocket in H(4)R with high steric precision. The use of the [1,2,3]triazole scaffold is further demonstrated by the notion that simple changes in spacer length or peripheral groups can reverse the selectivity toward H(3)R. Computational evidence is provided to account for two key selectivity switches and to pinpoint a lipophilic pocket as an important handle for H(4)R over H(3)R selectivity.
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Affiliation(s)
- Maikel Wijtmans
- Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Faculty of Exact Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
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32
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Seifert R, Schneider EH, Dove S, Brunskole I, Neumann D, Strasser A, Buschauer A. Paradoxical stimulatory effects of the "standard" histamine H4-receptor antagonist JNJ7777120: the H4 receptor joins the club of 7 transmembrane domain receptors exhibiting functional selectivity. Mol Pharmacol 2011; 79:631-8. [PMID: 21266488 DOI: 10.1124/mol.111.071266] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The histamine H(4) receptor (H(4)R) is expressed in several cell types of the immune system and is assumed to play an important pro-inflammatory role in various diseases, including bronchial asthma, atopic dermatitis, and pruritus. Accordingly, H(4)R antagonists have been suggested to provide valuable drugs for the treatment of these diseases. Over the past decade, the indole derivative 1-[(5-chloro-1H-indol-2-yl)carbonyl]-4-methylpiperazine (JNJ7777120) has become the "standard" H(4)R antagonist and has been extensively used to assess the pathophysiological role of the H(4)R. However, the situation has now become more complicated by recent data (p. 749 and Naunyn Schmiedebergs Arch Pharmacol doi: 10.1007/s00210-011-0612-3) showing that JNJ7777120 can also activate β-arrestin in a supposedly G(i)-protein-independent (pertussis toxin-insensitive) manner and that at certain H(4)R species orthologs, JNJ7777120 exhibits partial agonist efficacy with respect to G(i)-protein activation (steady-state high-affinity GTPase activity). These novel findings can be explained within the concept of functional selectivity or biased signaling, assuming unique ligand-specific receptor conformations with distinct signal transduction capabilities. Thus, great caution must be exerted when interpreting in vivo effects of JNJ7777120 as H(4)R antagonism. We discuss future directions to get out of the current dilemma in which there is no "standard" H(4)R antagonist available to the scientific community.
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Affiliation(s)
- Roland Seifert
- Institute of Pharmacology, Medical School of Hannover, Hannover, Germany.
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33
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Igel P, Dove S, Buschauer A. Histamine H4 receptor agonists. Bioorg Med Chem Lett 2010; 20:7191-9. [PMID: 21044842 DOI: 10.1016/j.bmcl.2010.10.041] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 10/08/2010] [Indexed: 10/18/2022]
Abstract
Since its discovery 10 years ago the histamine H(4) receptor (H(4)R) has attracted attention as a potential drug target, for instance, for the treatment of inflammatory and allergic diseases. Potent and selective ligands including agonists are required as pharmacological tools to study the role of the H(4)R in vitro and in vivo. Many H(4)R agonists, which were identified among already known histamine receptor ligands, show only low or insufficient H(4)R selectivity. In addition, the investigation of numerous H(4)R agonists in animal models is hampered by species-dependent discrepancies regarding potencies and histamine receptor selectivities of the available compounds, especially when comparing human and rodent receptors. This article gives an overview about structures, potencies, and selectivities of various compounds showing H(4)R agonistic activity and summarizes the structure-activity relationships of selected compound classes.
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Affiliation(s)
- Patrick Igel
- Department of Pharmaceutical/Medicinal Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Regensburg, Germany
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34
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Weiss S, Keller M, Bernhardt G, Buschauer A, König B. NG-Acyl-argininamides as NPY Y1 receptor antagonists: Influence of structurally diverse acyl substituents on stability and affinity. Bioorg Med Chem 2010; 18:6292-304. [DOI: 10.1016/j.bmc.2010.07.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 07/03/2010] [Accepted: 07/10/2010] [Indexed: 11/30/2022]
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35
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Kleinmaier R, Gschwind RM. Chemical shift assignment and conformational analysis of monoalkylated acylguanidines. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2010; 48:678-684. [PMID: 20641131 DOI: 10.1002/mrc.2648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Monoalkylated acylguanidines are important functional groups in many biologically active compounds and additionally applied in coordination chemistry. Yet a straightforward assignment of the individual NH chemical shifts and the acylguanidine conformations is still missing. Therefore, in this study, NMR spectroscopic approaches for the chemical and especially the conformational assignment of protonated monoalkylated acylguanidines are presented. While NOESY and (3)J(H, H) scalar couplings cannot be applied successfully for the assignment of acylguanidines, (4)J(H, H) scalar couplings in (1)H,(1)H COSY spectra allow for an unambiguous chemical shift and conformational assignment. It is shown that these (4)J(H, H) long-range couplings between individual acylguanidinium NH resonances are observed solely across all-trans (w) pathways. Already one cis orientation in the magnetisation transfer pathway leads to signal intensities below the actual detection limit and significantly lower than cross-peaks from (2)J(NH, NH) couplings or chemical exchange. However, it should be noted that also in the case of conformational exchange being fast on the NMR time scale, averaged cross-peaks from all-trans (4)J(H, H) scalar couplings are detected, which may lead at first glance to an incomplete or even wrong conformational analysis.
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Affiliation(s)
- Roland Kleinmaier
- Institut für Organische Chemie, Universität Regensburg, D-93053 Regensburg, Germany
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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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Kleinmaier R, Keller M, Igel P, Buschauer A, Gschwind RM. Conformations, Conformational Preferences, and Conformational Exchange of N′-Substituted N-Acylguanidines: Intermolecular Interactions Hold the Key. J Am Chem Soc 2010; 132:11223-33. [DOI: 10.1021/ja103756y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Roland Kleinmaier
- Institut für Organische Chemie and Institut für Pharmazie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Max Keller
- Institut für Organische Chemie and Institut für Pharmazie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Patrick Igel
- Institut für Organische Chemie and Institut für Pharmazie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Armin Buschauer
- Institut für Organische Chemie and Institut für Pharmazie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Ruth M. Gschwind
- Institut für Organische Chemie and Institut für Pharmazie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
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Ghorai P, Kraus A, Birnkammer T, Geyer R, Bernhardt G, Dove S, Seifert R, Elz S, Buschauer A. Chiral NG-acylated hetarylpropylguanidine-type histamine H2 receptor agonists do not show significant stereoselectivity. Bioorg Med Chem Lett 2010; 20:3173-6. [DOI: 10.1016/j.bmcl.2010.03.082] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 03/22/2010] [Accepted: 03/23/2010] [Indexed: 10/19/2022]
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Berlinck RGS, Burtoloso ACB, Trindade-Silva AE, Romminger S, Morais RP, Bandeira K, Mizuno CM. The chemistry and biology of organic guanidine derivatives. Nat Prod Rep 2010; 27:1871-907. [DOI: 10.1039/c0np00016g] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Igel P, Geyer R, Strasser A, Dove S, Seifert R, Buschauer A. Synthesis and structure-activity relationships of cyanoguanidine-type and structurally related histamine H4 receptor agonists. J Med Chem 2009; 52:6297-313. [PMID: 19791743 DOI: 10.1021/jm900526h] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recently, we identified high-affinity human histamine H3 (hH3R) and H4 receptor (hH4R) ligands among a series of NG-acylated imidazolylpropylguanidines, which were originally designed as histamine H2 receptor (H2R) agonists. Aiming at selectivity for hH4R, the acylguanidine group was replaced with related moieties. Within a series of cyanoguanidines, 2-cyano-1-[4-(1H-imidazol-4-yl)butyl]-3-[(2-phenylthio)ethyl]guanidine (UR-PI376, 67) was identified as the most potent hH4R agonist (pEC50 = 7.47, alpha = 0.93) showing negligible hH1R and hH2R activities and significant selectivity over the hH3R (pKB = 6.00, alpha = -0.28), as determined in steady-state GTPase assays using membrane preparations of hH(x)R-expressing Sf9 cells. In contrast to previously described selective H4R agonists, this compound and other 3-substituted derivatives are devoid of agonistic activity at the other HR subtypes. Modeling of the binding mode of 67 suggests that the cyanoguanidine moiety forms charge-assisted hydrogen bonds not only with the conserved Asp-94 but also with the hH4R-specific Arg-341 residue. 2-Carbamoyl-1-[2-(1H-imidazol-4-yl)ethyl]-3-(3-phenylpropyl)guanidine (UR-PI97, 88) was unexpectedly identified as a highly potent and selective hH3R inverse agonist (pKB = 8.42, >300-fold selectivity over the other HR subtypes).
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Affiliation(s)
- Patrick Igel
- Department of Pharmaceutical/Medicinal Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitatsstrasse 31, D-93053 Regensburg, Germany
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Histamine H3 and H4 receptor affinity of branched 3-(1H-imidazol-4-yl)propyl N-alkylcarbamates. Bioorg Med Chem Lett 2009; 19:6682-5. [PMID: 19846299 DOI: 10.1016/j.bmcl.2009.10.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 09/30/2009] [Accepted: 10/01/2009] [Indexed: 11/22/2022]
Abstract
A series of imidazole-containing (non-)chiral carbamates were tested at human histamine H(3) receptor (H(3)R). All compounds displayed K(i) values below 100 nM. A trend for a stereoselectivity at human H(3)R was observed for the chiral alpha-branched ligands. Selected compounds were also tested at human histamine H(4) receptor and showed moderate to weak affinities (118-1460 nM).
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Tiligada E, Zampeli E, Sander K, Stark H. Histamine H3and H4receptors as novel drug targets. Expert Opin Investig Drugs 2009; 18:1519-31. [DOI: 10.1517/14728220903188438] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Strasser A. Molecular modeling and QSAR-based design of histamine receptor ligands. Expert Opin Drug Discov 2009; 4:1061-75. [DOI: 10.1517/17460440903264972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Deml KF, Beermann S, Neumann D, Strasser A, Seifert R. Interactions of histamine H1-receptor agonists and antagonists with the human histamine H4-receptor. Mol Pharmacol 2009; 76:1019-30. [PMID: 19720730 DOI: 10.1124/mol.109.058651] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The human histamine H(4)-receptor (hH(4)R) possesses high constitutive activity and, like the human H(1)-receptor (hH(1)R), is involved in the pathogenesis of type-I allergic reactions. The study aims were to explore the value of dual H(1)/H(4)R antagonists as antiallergy drugs and to address the question of whether H(1)R ligands bind to hH(4)R. In an acute murine asthma model, the H(1)R antagonist mepyramine and the H(4)R antagonist 1-[(5-chloro-1H-indol-2-yl)carbonyl]-4-methyl-piperazine (JNJ 7777120) exhibited synergistic inhibitory effects on eosinophil accumulation in the bronchoalveolar lavage fluid. At the hH(4)R expressed in Sf9 insect cells, 18 H(1)R antagonists and 22 H(1)R agonists showed lower affinity to hH(4)R than to hH(1)R as assessed in competition binding experiments. For a small number of H(1)R antagonists, hH(4)R partial agonism was observed in the steady-state GTPase assay. Most compounds were neutral antagonists or inverse agonists. Twelve phenylhistamine-type hH(1)R partial agonists were also hH(4)R partial agonists. Four histaprodifen-type hH(1)R partial agonists were hH(4)R inverse agonists. Dimeric histaprodifen was a more efficacious hH(4)R inverse agonist than the reference compound thioperamide. Suprahistaprodifen was the only histaprodifen acting as hH(4)R partial agonist. Suprahistaprodifen was docked into the binding pocket of inactive and active hH(4)R models in two different orientations, predominantly stabilizing the active state of hH(4)R. Collectively, the synergistic effects of H(1)R and H(4)R antagonists in an acute asthma model and the overlapping interaction of structurally diverse H(1)R ligands with hH(1)R and hH(4)R indicate that the development of dual H(1)R/H(4)R antagonists is a worthwhile and technically feasible goal for the treatment of type-I allergic reactions.
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Affiliation(s)
- Karl-Friedrich Deml
- Department of Pharmacology, School of Pharmacy, University of Regensburg, Regensburg, Germany
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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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