The Experts below are selected from a list of 38820 Experts worldwide ranked by ideXlab platform
Adriaan P Ijzerman - One of the best experts on this subject based on the ideXlab platform.
-
Development of Covalent Ligands for G Protein-Coupled Receptors: A Case for the Human Adenosine A3 Receptor
2019Co-Authors: Xue Yang, Laura H Heitman, Jacobus P. D. Van Veldhoven, Jelle Offringa, Boaz J. Kuiper, Eelke B. Lenselink, Daan Van Der Es, Adriaan P IjzermanAbstract:The development of covalent ligands for G protein-coupled Receptors (GPCRs) is not a trivial process. Here, we report a streamlined workflow thereto from synthesis to validation, exemplified by the discovery of a covalent antagonist for the human Adenosine A3 Receptor (hA3AR). Based on the 1H,3H-pyrido[2,1-f]purine-2,4-dione scaffold, a series of ligands bearing a fluorosulfonyl warhead and a varying linker was synthesized. This series was subjected to an affinity screen, revealing compound 17b as the most potent antagonist. In addition, a nonreactive methylsulfonyl derivative 19 was developed as a reversible control compound. A series of assays, comprising time-dependent affinity determination, washout experiments, and [35S]GTPγS binding assays, then validated 17b as the covalent antagonist. A combined in silico hA3AR-homology model and site-directed mutagenesis study was performed to demonstrate that amino acid residue Y2657.36 was the unique anchor point of the covalent interaction. This workflow might be applied to other GPCRs to guide the discovery of covalent ligands
-
a binding kinetics study of human Adenosine A3 Receptor agonists
Biochemical Pharmacology, 2018Co-Authors: Lizi Xia, Adriaan P Ijzerman, Athina Kyrizaki, Dilip K Tosh, Tirsa T Van Duijl, Jacomina Cornelia Roorda, Kenneth A Jacobson, Laura H HeitmanAbstract:The human Adenosine A(3) (hA(3)) Receptor has been suggested as a viable drug target in inflammatory diseases and in cancer. So far, a number of selective hA(3) Receptor agonists (e.g. IB-MECA and 2-CI-IB-MECA) inducing anti-inflammatory or anticancer effects are under clinical investigation. Drug-target binding kinetics is increasingly recognized as another pharmacological parameter, next to affinity, for compound triage in the early phases of drug discovery. However, such a kinetics-driven analysis has not yet been performed for the hA3 Receptor. In this study, we first validated a competition association assay for Adenosine A3 Receptor agonists to determine the target interaction kinetics. Affinities and Kinetic Rate Index (KRI) values of 11 ribofurano and 10 methanocarba nucleosides were determined in radioligand binding assays. Afterwards, 15 analogues were further selected (KRI 1.35) for full kinetics characterization. The structure-kinetics relationships (SKR) were derived and longer residence times were associated with methanocarba and enlarged adenine N-6 and C2 substitutions. In addition, from a k(on)-k(off)K(D) kinetic map we divided the agonists into three subgroups. A residence time "cliff' was observed, which might be relevant to (N)-methanocarba derivatives' rigid C2-arylalkynyl substitutions. Our findings provide substantial evidence that, next to affinity, additional knowledge of binding kinetics is useful for developing and selecting new hA(3)R agonists in the early phase of the drug discovery process.
-
structure affinity relationships and structure kinetics relationships of pyrido 2 1 f purine 2 4 dione derivatives as human Adenosine A3 Receptor antagonists
Journal of Medicinal Chemistry, 2017Co-Authors: Lizi Xia, Laura H Heitman, Tirsa T Van Duijl, Jacobus P. D. Van Veldhoven, Boaz J. Kuiper, Eelke B. Lenselink, Wessel A. C. Burger, Ellen Paasman, Adriaan P IjzermanAbstract:We expanded on a series of pyrido[2,1-f]purine-2,4-dione derivatives as human Adenosine A3 Receptor (hA3R) antagonists to determine their kinetic profiles and affinities. Many compounds showed high affinities and a diverse range of kinetic profiles. We found hA3R antagonists with very short residence time (RT) at the Receptor (2.2 min for 5) and much longer RTs (e.g., 376 min for 27 or 391 min for 31). Two representative antagonists (5 and 27) were tested in [35S]GTPγS binding assays, and their RTs appeared correlated to their (in)surmountable antagonism. From a kon–koff–KD kinetic map, we divided the antagonists into three subgroups, providing a possible direction for the further development of hA3R antagonists. Additionally, we performed a computational modeling study that sheds light on the crucial Receptor interactions, dictating the compounds’ binding kinetics. Knowledge of target binding kinetics appears useful for developing and triaging new hA3R antagonists in the early phase of drug discovery.
-
Structure–Affinity Relationships and Structure–Kinetics Relationships of Pyrido[2,1‑f]purine-2,4-dione Derivatives as Human Adenosine A3 Receptor Antagonists
2017Co-Authors: Lizi Xia, Laura H Heitman, Tirsa T Van Duijl, Jacobus P. D. Van Veldhoven, Boaz J. Kuiper, Eelke B. Lenselink, Wessel A. C. Burger, Ellen Paasman, Adriaan P IjzermanAbstract:We expanded on a series of pyrido[2,1-f]purine-2,4-dione derivatives as human Adenosine A3 Receptor (hA3R) antagonists to determine their kinetic profiles and affinities. Many compounds showed high affinities and a diverse range of kinetic profiles. We found hA3R antagonists with very short residence time (RT) at the Receptor (2.2 min for 5) and much longer RTs (e.g., 376 min for 27 or 391 min for 31). Two representative antagonists (5 and 27) were tested in [35S]GTPγS binding assays, and their RTs appeared correlated to their (in)surmountable antagonism. From a kon–koff–KD kinetic map, we divided the antagonists into three subgroups, providing a possible direction for the further development of hA3R antagonists. Additionally, we performed a computational modeling study that sheds light on the crucial Receptor interactions, dictating the compounds’ binding kinetics. Knowledge of target binding kinetics appears useful for developing and triaging new hA3R antagonists in the early phase of drug discovery
-
isoquinoline and quinazoline urea analogues as antagonists for the human Adenosine A3 Receptor
Journal of the American Chemical Society, 2000Co-Authors: J E Van Muijlwijkkoezen, Henk Timmerman, H Van Der Goot, W M P B Menge, Frijtag F Von Drabbe Kunzel, M J De Groot, Adriaan P IjzermanAbstract:Isoquinoline and quinazoline urea derivatives were found to bind to human Adenosine A3 Receptors. Series of N-phenyl-N‘-quinazolin-4-ylurea derivatives and N-phenyl-N‘-isoquinolin-1-ylurea derivatives were synthesized and tested in radioligand binding assays on their Adenosine Receptor affinities. A structure−affinity analysis indicated that on the 2-position of the quinazoline ring or the equivalent 3-position of the isoquinoline ring a phenyl or heteroaryl substituent increased the Adenosine A3 Receptor affinity in comparison to unsubstituted or aliphatic derivatives. Furthermore, the structure−affinity relationship of substituted phenylurea analogues was investigated. Substituents such as electron-withdrawing or electron-donating groups were introduced at different positions of the benzene ring to probe electronic and positional effects of substitution. Substitution on the 3- or 4-position of the phenyl ring decreased the Adenosine A3 Receptor affinity. Substitution at position 2 with an electron-donat...
Kenneth A Jacobson - One of the best experts on this subject based on the ideXlab platform.
-
Adenosine A3 Receptor activation inhibits pronociceptive n type ca2 currents and cell excitability in dorsal root ganglion neurons
Pain, 2019Co-Authors: Elisabetta Coppi, Kenneth A Jacobson, Federica Cherchi, Irene Fusco, Paola Failli, Alessia Vona, Ilaria Dettori, Lisa Gaviano, Elena Lucarini, Dilip K ToshAbstract:Recently, studies have focused on the antihyperalgesic activity of the A3 Adenosine Receptor (A3AR) in several chronic pain models, but the cellular and molecular basis of this effect is still unknown. Here, we investigated the expression and functional effects of A3AR on the excitability of small- to medium-sized, capsaicin-sensitive, dorsal root ganglion (DRG) neurons isolated from 3- to 4-week-old rats. Real-time quantitative polymerase chain reaction experiments and immunofluorescence analysis revealed A3AR expression in DRG neurons. Patch-clamp experiments demonstrated that 2 distinct A3AR agonists, Cl-IB-MECA and the highly selective MRS5980, inhibited Ca-activated K (KCa) currents evoked by a voltage-ramp protocol. This effect was dependent on a reduction in Ca influx via N-type voltage-dependent Ca channels, as Cl-IB-MECA-induced inhibition was sensitive to the N-type blocker PD173212 but not to the L-type blocker, lacidipine. The endogenous agonist Adenosine also reduced N-type Ca currents, and its effect was inhibited by 56% in the presence of A3AR antagonist MRS1523, demonstrating that the majority of Adenosine's effect is mediated by this Receptor subtype. Current-clamp recordings demonstrated that neuronal firing of rat DRG neurons was also significantly reduced by A3AR activation in a MRS1523-sensitive but PD173212-insensitive manner. Intracellular Ca measurements confirmed the inhibitory role of A3AR on DRG neuronal firing. We conclude that pain-relieving effects observed on A3AR activation could be mediated through N-type Ca channel block and action potential inhibition as independent mechanisms in isolated rat DRG neurons. These findings support A3AR-based therapy as a viable approach to alleviate pain in different pathologies.
-
a binding kinetics study of human Adenosine A3 Receptor agonists
Biochemical Pharmacology, 2018Co-Authors: Lizi Xia, Adriaan P Ijzerman, Athina Kyrizaki, Dilip K Tosh, Tirsa T Van Duijl, Jacomina Cornelia Roorda, Kenneth A Jacobson, Laura H HeitmanAbstract:The human Adenosine A(3) (hA(3)) Receptor has been suggested as a viable drug target in inflammatory diseases and in cancer. So far, a number of selective hA(3) Receptor agonists (e.g. IB-MECA and 2-CI-IB-MECA) inducing anti-inflammatory or anticancer effects are under clinical investigation. Drug-target binding kinetics is increasingly recognized as another pharmacological parameter, next to affinity, for compound triage in the early phases of drug discovery. However, such a kinetics-driven analysis has not yet been performed for the hA3 Receptor. In this study, we first validated a competition association assay for Adenosine A3 Receptor agonists to determine the target interaction kinetics. Affinities and Kinetic Rate Index (KRI) values of 11 ribofurano and 10 methanocarba nucleosides were determined in radioligand binding assays. Afterwards, 15 analogues were further selected (KRI 1.35) for full kinetics characterization. The structure-kinetics relationships (SKR) were derived and longer residence times were associated with methanocarba and enlarged adenine N-6 and C2 substitutions. In addition, from a k(on)-k(off)K(D) kinetic map we divided the agonists into three subgroups. A residence time "cliff' was observed, which might be relevant to (N)-methanocarba derivatives' rigid C2-arylalkynyl substitutions. Our findings provide substantial evidence that, next to affinity, additional knowledge of binding kinetics is useful for developing and selecting new hA(3)R agonists in the early phase of the drug discovery process.
-
peripheral Adenosine A3 Receptor activation causes regulated hypothermia in mice that is dependent on central histamine h1 Receptors
Journal of Pharmacology and Experimental Therapeutics, 2016Co-Authors: Jesse Lea Carlin, Dilip K Tosh, Kenneth A Jacobson, Cuiying Xiao, Ramon A Pinol, Zhoumou Chen, Daniela Salvemini, Oksana Gavrilova, Marc L ReitmanAbstract:Adenosine can induce hypothermia, as previously demonstrated for Adenosine A1 Receptor (A1AR) agonists. Here we use the potent, specific A3AR agonists MRS5698, MRS5841, and MRS5980 to show that Adenosine also induces hypothermia via the A3AR. The hypothermic effect of A3AR agonists is independent of A1AR activation, as the effect was fully intact in mice lacking A1AR but abolished in mice lacking A3AR. A3AR agonist-induced hypothermia was attenuated by mast cell granule depletion, demonstrating that the A3AR hypothermia is mediated, at least in part, via mast cells. Central agonist dosing had no clear hypothermic effect, whereas peripheral dosing of a non-brain-penetrant agonist caused hypothermia, suggesting that peripheral A3AR-expressing cells drive the hypothermia. Mast cells release histamine, and blocking central histamine H1 (but not H2 or H4) Receptors prevented the hypothermia. The hypothermia was preceded by hypometabolism and mice with hypothermia preferred a cooler environmental temperature, demonstrating that the hypothermic state is a coordinated physiologic response with a reduced body temperature set point. Importantly, hypothermia is not required for the analgesic effects of A3AR agonists, which occur with lower agonist doses. These results support a mechanistic model for hypothermia in which A3AR agonists act on peripheral mast cells, causing histamine release, which stimulates central histamine H1 Receptors to induce hypothermia. This mechanism suggests that A3AR agonists will probably not be useful for clinical induction of hypothermia.
-
predicted structures of agonist and antagonist bound complexes of Adenosine A3 Receptor
Proteins, 2011Co-Authors: Lindsay Riley, Kenneth A Jacobson, Ravinder Abrol, William A GoddardAbstract:We used the GEnSeMBLE Monte Carlo method to predict ensemble of the 20 best packings (helix rotations and tilts) based on the neutral total energy (E) from a vast number (10 trillion) of potential packings for each of the four subtypes of the Adenosine G protein-coupled Receptors (GPCRs), which are involved in many cytoprotective functions. We then used the DarwinDock Monte Carlo methods to predict the binding pose for the human A_3 Adenosine Receptor (hAA_3R) for subtype selective agonists and antagonists. We found that all four A_3 agonists stabilize the 15th lowest conformation of apo-hAA_3R while also binding strongly to the 1st and 3rd. In contrast the four A_3 antagonists stabilize the 2nd or 3rd lowest conformation. These results show that different ligands can stabilize different GPCR conformations, which will likely affect function, complicating the design of functionally unique ligands. Interestingly all agonists lead to a trans χ1 angle for W6.48 that experiments on other GPCRs associate with G-protein activation while all 20 apo-AA_3R conformations have a W6.48 gauche+ χ1 angle associated experimentally with inactive GPCRs for other systems. Thus docking calculations have identified critical ligand-GPCR structures involved with activation. We found that the predicted binding site for selective agonist Cl-IB-MECA to the predicted structure of hAA_3R shows favorable interactions to three subtype variable residues, I253^(6.58), V169^(EL2), and Q167^(EL2), while the predicted structure for hAA_(2A)R shows weakened to the corresponding amino acids: T256^(6.58), E169^(EL2), and L167^(EL2), explaining the observed subtype selectivity.
-
techniques recent developments in computer aided engineering of gpcr ligands using the human Adenosine A3 Receptor as an example
Trends in Pharmacological Sciences, 2005Co-Authors: Stefano Moro, Giampiero Spalluto, Kenneth A JacobsonAbstract:G-protein-coupled Receptors (GPCRs) represent the largest known family of signal-transducing molecules, and convey signals for light and many extracellular regulatory molecules. GPCRs are dysfunctional or dysregulated in several human diseases and are estimated to be the targets of >40% of the drugs used in clinical medicine today. The crystal structure of rhodopsin provides the first information on the three-dimensional structure of GPCRs, which now supports homology modeling studies and structure-based drug-design approaches. In this article, we review recent work on Adenosine Receptors, a family of GPCRs, and, in particular, on Adenosine A 3 Receptor antagonists. We focus on an iterative, bi-directional approach in which models are used to generate hypotheses that are tested by experimentation; the experimental findings are, in turn, used to refine the model. The success of this approach is due to the synergistic interaction between theory and experimentation.
Laura H Heitman - One of the best experts on this subject based on the ideXlab platform.
-
Development of Covalent Ligands for G Protein-Coupled Receptors: A Case for the Human Adenosine A3 Receptor
2019Co-Authors: Xue Yang, Laura H Heitman, Jacobus P. D. Van Veldhoven, Jelle Offringa, Boaz J. Kuiper, Eelke B. Lenselink, Daan Van Der Es, Adriaan P IjzermanAbstract:The development of covalent ligands for G protein-coupled Receptors (GPCRs) is not a trivial process. Here, we report a streamlined workflow thereto from synthesis to validation, exemplified by the discovery of a covalent antagonist for the human Adenosine A3 Receptor (hA3AR). Based on the 1H,3H-pyrido[2,1-f]purine-2,4-dione scaffold, a series of ligands bearing a fluorosulfonyl warhead and a varying linker was synthesized. This series was subjected to an affinity screen, revealing compound 17b as the most potent antagonist. In addition, a nonreactive methylsulfonyl derivative 19 was developed as a reversible control compound. A series of assays, comprising time-dependent affinity determination, washout experiments, and [35S]GTPγS binding assays, then validated 17b as the covalent antagonist. A combined in silico hA3AR-homology model and site-directed mutagenesis study was performed to demonstrate that amino acid residue Y2657.36 was the unique anchor point of the covalent interaction. This workflow might be applied to other GPCRs to guide the discovery of covalent ligands
-
a binding kinetics study of human Adenosine A3 Receptor agonists
Biochemical Pharmacology, 2018Co-Authors: Lizi Xia, Adriaan P Ijzerman, Athina Kyrizaki, Dilip K Tosh, Tirsa T Van Duijl, Jacomina Cornelia Roorda, Kenneth A Jacobson, Laura H HeitmanAbstract:The human Adenosine A(3) (hA(3)) Receptor has been suggested as a viable drug target in inflammatory diseases and in cancer. So far, a number of selective hA(3) Receptor agonists (e.g. IB-MECA and 2-CI-IB-MECA) inducing anti-inflammatory or anticancer effects are under clinical investigation. Drug-target binding kinetics is increasingly recognized as another pharmacological parameter, next to affinity, for compound triage in the early phases of drug discovery. However, such a kinetics-driven analysis has not yet been performed for the hA3 Receptor. In this study, we first validated a competition association assay for Adenosine A3 Receptor agonists to determine the target interaction kinetics. Affinities and Kinetic Rate Index (KRI) values of 11 ribofurano and 10 methanocarba nucleosides were determined in radioligand binding assays. Afterwards, 15 analogues were further selected (KRI 1.35) for full kinetics characterization. The structure-kinetics relationships (SKR) were derived and longer residence times were associated with methanocarba and enlarged adenine N-6 and C2 substitutions. In addition, from a k(on)-k(off)K(D) kinetic map we divided the agonists into three subgroups. A residence time "cliff' was observed, which might be relevant to (N)-methanocarba derivatives' rigid C2-arylalkynyl substitutions. Our findings provide substantial evidence that, next to affinity, additional knowledge of binding kinetics is useful for developing and selecting new hA(3)R agonists in the early phase of the drug discovery process.
-
structure affinity relationships and structure kinetics relationships of pyrido 2 1 f purine 2 4 dione derivatives as human Adenosine A3 Receptor antagonists
Journal of Medicinal Chemistry, 2017Co-Authors: Lizi Xia, Laura H Heitman, Tirsa T Van Duijl, Jacobus P. D. Van Veldhoven, Boaz J. Kuiper, Eelke B. Lenselink, Wessel A. C. Burger, Ellen Paasman, Adriaan P IjzermanAbstract:We expanded on a series of pyrido[2,1-f]purine-2,4-dione derivatives as human Adenosine A3 Receptor (hA3R) antagonists to determine their kinetic profiles and affinities. Many compounds showed high affinities and a diverse range of kinetic profiles. We found hA3R antagonists with very short residence time (RT) at the Receptor (2.2 min for 5) and much longer RTs (e.g., 376 min for 27 or 391 min for 31). Two representative antagonists (5 and 27) were tested in [35S]GTPγS binding assays, and their RTs appeared correlated to their (in)surmountable antagonism. From a kon–koff–KD kinetic map, we divided the antagonists into three subgroups, providing a possible direction for the further development of hA3R antagonists. Additionally, we performed a computational modeling study that sheds light on the crucial Receptor interactions, dictating the compounds’ binding kinetics. Knowledge of target binding kinetics appears useful for developing and triaging new hA3R antagonists in the early phase of drug discovery.
-
Structure–Affinity Relationships and Structure–Kinetics Relationships of Pyrido[2,1‑f]purine-2,4-dione Derivatives as Human Adenosine A3 Receptor Antagonists
2017Co-Authors: Lizi Xia, Laura H Heitman, Tirsa T Van Duijl, Jacobus P. D. Van Veldhoven, Boaz J. Kuiper, Eelke B. Lenselink, Wessel A. C. Burger, Ellen Paasman, Adriaan P IjzermanAbstract:We expanded on a series of pyrido[2,1-f]purine-2,4-dione derivatives as human Adenosine A3 Receptor (hA3R) antagonists to determine their kinetic profiles and affinities. Many compounds showed high affinities and a diverse range of kinetic profiles. We found hA3R antagonists with very short residence time (RT) at the Receptor (2.2 min for 5) and much longer RTs (e.g., 376 min for 27 or 391 min for 31). Two representative antagonists (5 and 27) were tested in [35S]GTPγS binding assays, and their RTs appeared correlated to their (in)surmountable antagonism. From a kon–koff–KD kinetic map, we divided the antagonists into three subgroups, providing a possible direction for the further development of hA3R antagonists. Additionally, we performed a computational modeling study that sheds light on the crucial Receptor interactions, dictating the compounds’ binding kinetics. Knowledge of target binding kinetics appears useful for developing and triaging new hA3R antagonists in the early phase of drug discovery
Lizi Xia - One of the best experts on this subject based on the ideXlab platform.
-
a binding kinetics study of human Adenosine A3 Receptor agonists
Biochemical Pharmacology, 2018Co-Authors: Lizi Xia, Adriaan P Ijzerman, Athina Kyrizaki, Dilip K Tosh, Tirsa T Van Duijl, Jacomina Cornelia Roorda, Kenneth A Jacobson, Laura H HeitmanAbstract:The human Adenosine A(3) (hA(3)) Receptor has been suggested as a viable drug target in inflammatory diseases and in cancer. So far, a number of selective hA(3) Receptor agonists (e.g. IB-MECA and 2-CI-IB-MECA) inducing anti-inflammatory or anticancer effects are under clinical investigation. Drug-target binding kinetics is increasingly recognized as another pharmacological parameter, next to affinity, for compound triage in the early phases of drug discovery. However, such a kinetics-driven analysis has not yet been performed for the hA3 Receptor. In this study, we first validated a competition association assay for Adenosine A3 Receptor agonists to determine the target interaction kinetics. Affinities and Kinetic Rate Index (KRI) values of 11 ribofurano and 10 methanocarba nucleosides were determined in radioligand binding assays. Afterwards, 15 analogues were further selected (KRI 1.35) for full kinetics characterization. The structure-kinetics relationships (SKR) were derived and longer residence times were associated with methanocarba and enlarged adenine N-6 and C2 substitutions. In addition, from a k(on)-k(off)K(D) kinetic map we divided the agonists into three subgroups. A residence time "cliff' was observed, which might be relevant to (N)-methanocarba derivatives' rigid C2-arylalkynyl substitutions. Our findings provide substantial evidence that, next to affinity, additional knowledge of binding kinetics is useful for developing and selecting new hA(3)R agonists in the early phase of the drug discovery process.
-
structure affinity relationships and structure kinetics relationships of pyrido 2 1 f purine 2 4 dione derivatives as human Adenosine A3 Receptor antagonists
Journal of Medicinal Chemistry, 2017Co-Authors: Lizi Xia, Laura H Heitman, Tirsa T Van Duijl, Jacobus P. D. Van Veldhoven, Boaz J. Kuiper, Eelke B. Lenselink, Wessel A. C. Burger, Ellen Paasman, Adriaan P IjzermanAbstract:We expanded on a series of pyrido[2,1-f]purine-2,4-dione derivatives as human Adenosine A3 Receptor (hA3R) antagonists to determine their kinetic profiles and affinities. Many compounds showed high affinities and a diverse range of kinetic profiles. We found hA3R antagonists with very short residence time (RT) at the Receptor (2.2 min for 5) and much longer RTs (e.g., 376 min for 27 or 391 min for 31). Two representative antagonists (5 and 27) were tested in [35S]GTPγS binding assays, and their RTs appeared correlated to their (in)surmountable antagonism. From a kon–koff–KD kinetic map, we divided the antagonists into three subgroups, providing a possible direction for the further development of hA3R antagonists. Additionally, we performed a computational modeling study that sheds light on the crucial Receptor interactions, dictating the compounds’ binding kinetics. Knowledge of target binding kinetics appears useful for developing and triaging new hA3R antagonists in the early phase of drug discovery.
-
Structure–Affinity Relationships and Structure–Kinetics Relationships of Pyrido[2,1‑f]purine-2,4-dione Derivatives as Human Adenosine A3 Receptor Antagonists
2017Co-Authors: Lizi Xia, Laura H Heitman, Tirsa T Van Duijl, Jacobus P. D. Van Veldhoven, Boaz J. Kuiper, Eelke B. Lenselink, Wessel A. C. Burger, Ellen Paasman, Adriaan P IjzermanAbstract:We expanded on a series of pyrido[2,1-f]purine-2,4-dione derivatives as human Adenosine A3 Receptor (hA3R) antagonists to determine their kinetic profiles and affinities. Many compounds showed high affinities and a diverse range of kinetic profiles. We found hA3R antagonists with very short residence time (RT) at the Receptor (2.2 min for 5) and much longer RTs (e.g., 376 min for 27 or 391 min for 31). Two representative antagonists (5 and 27) were tested in [35S]GTPγS binding assays, and their RTs appeared correlated to their (in)surmountable antagonism. From a kon–koff–KD kinetic map, we divided the antagonists into three subgroups, providing a possible direction for the further development of hA3R antagonists. Additionally, we performed a computational modeling study that sheds light on the crucial Receptor interactions, dictating the compounds’ binding kinetics. Knowledge of target binding kinetics appears useful for developing and triaging new hA3R antagonists in the early phase of drug discovery
Carol Terminelli - One of the best experts on this subject based on the ideXlab platform.
-
a role for histamine in cytokine modulation by the Adenosine A3 Receptor agonist 2 cl ib meca
European Journal of Pharmacology, 2002Co-Authors: Sidney R Smith, Georgetta Denhardt, Carol TerminelliAbstract:Abstract The effects of Adenosine Receptor agonists on cytokine production in vivo were investigated in mouse models of endotoxemia. Selective Adenosine A 3 (2-chloro- N 6 -(3-iodobenzyl) Adenosine-5′- N -methyluronamide) (2-Cl-IB-MECA) and A 2A (2- p -(2-carboxyethyl) phenethylamino-5′- N -ethylcarboxamido Adenosine hydrochloride) (CGS 21860) Receptor agonists were found to modulate endotoxin-induced cytokine responses in mice sensitized to d -galactosamine or primed with Corynebacterium parvum . The Adenosine Receptor agonists had similar effects in these models of endotoxemia, suppressing the production of tumor necrosis factor α (TNF-α) and interleukin-12 while enhancing that of interleukin-10. However, 2-Cl-IB-MECA also caused a dramatic increase in circulating histamine levels shortly after its injection into mice. The cytokine modulatory activities of 2-Cl-IB-MECA were mimicked by the mast cell depleting compound 48/80 and both drugs only produced such effects at doses that caused an elevation in circulating histamine levels. Furthermore, the capacity of 2-Cl-IB-MECA to modulate cytokine responses was greatly diminished when the drug was administered to mast cell deficient (WBB6F-W/W V ) mice. Together, these results strongly suggest a role for histamine in cytokine modulation by 2-Cl-IB-MECA. Cimetidine, a histamine H 2 Receptor antagonist, did not reverse cytokine modulation by 2-Cl-IB-MECA and pyrilamine, a histamine H 1 Receptor antagonist, prevented the increase in serum histamine that was induced by 2-Cl-IB-MECA. This effect of pyrilamine and other histamine H 1 Receptor antagonists confounded attempts to determine a role for the histamine H 1 Receptor in cytokine modulation by 2-Cl-IB-MECA. However, under some experimental conditions, pyrilamine appeared to antagonize the modulatory effects of the Adenosine A 3 Receptor agonist on cytokine responses. The apparent antagonism of pyrilamine was unrelated to its suppressive effects on histamine release and appeared to reflect activity at the level of the histamine H 1 Receptor.