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Fisher CL, Pavan M, Salmaso V, Keyes RF, Wan TC, Pradhan B, Gao ZG, Smith BC, Jacobson KA, Auchampach JA. Extrahelical Binding Site for a 1 H-Imidazo[4,5-c]quinolin-4-amine A 3 Adenosine Receptor Positive Allosteric Modulator on Helix 8 and Distal Portions of Transmembrane Domains 1 and 7. Mol Pharmacol 2024; 105:213-223. [PMID: 38182432 PMCID: PMC10877738 DOI: 10.1124/molpharm.123.000784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/27/2023] [Accepted: 12/12/2023] [Indexed: 01/07/2024] Open
Abstract
This study describes the localization and computational prediction of a binding site for the A3 adenosine receptor (A3AR) positive allosteric modulator 2-cyclohexyl-1H-imidazo[4,5-c]quinolin-4-(3,4-dichlorophenyl)amine (LUF6000). The work reveals an extrahelical lipid-facing binding pocket disparate from the orthosteric binding site that encompasses transmembrane domain (TMD) 1, TMD7, and Helix (H) 8, which was predicted by molecular modeling and validated by mutagenesis. According to the model, the nearly planar 1H-imidazo[4,5-c]quinolinamine ring system lies parallel to the transmembrane segments, inserted into an aromatic cage formed by π-π stacking interactions with the side chains of Y2847.55 in TMD7 and Y2938.54 in H8 and by π-NH bonding between Y2847.55 and the exocyclic amine. The 2-cyclohexyl group is positioned "upward" within a small hydrophobic subpocket created by residues in TMDs 1 and 7, while the 3,4-dichlorophenyl group extends toward the lipid interface. An H-bond between the N-1 amine of the heterocycle and the carbonyl of G291.49 further stabilizes the interaction. Molecular dynamics simulations predicted two metastable intermediates, one resembling a pose determined by molecular docking and a second involving transient interactions with Y2938.54; in simulations, each of these intermediates converges into the final bound state. Structure-activity-relationships for replacement of either of the identified exocyclic or endocyclic amines with heteroatoms lacking H-bond donating ability were consistent with the hypothetical pose. Thus, we characterized an allosteric pocket for 1H-imidazo[4,5-c]quinolin-4-amines that is consistent with data generated by orthogonal methods, which will aid in the rational design of improved A3AR positive allosteric modulators. SIGNIFICANCE STATEMENT: Orthosteric A3AR agonists have advanced in clinical trials for inflammatory conditions, liver diseases, and cancer. Thus, the clinical appeal of selective receptor activation could extend to allosteric enhancers, which would induce site- and time-specific activation in the affected tissue. By identifying the allosteric site for known positive allosteric modulators, structure-based drug discovery modalities can be enabled to enhance the pharmacological properties of the 1H-imidazo[4,5-c]quinolin-4-amine class of A3AR positive allosteric modulators.
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Affiliation(s)
- Courtney L Fisher
- Departments of Pharmacology & Toxicology and the Cardiovascular Center (C.L.F., T.C.W., J.A.A.) and Biochemistry and the Program in Chemical Biology (R.F.K., B.C.S.), Medical College of Wisconsin, Milwaukee, Wisconsin; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland (M.P., V.S., B.P., Z.-G.G., K.A.J.); and Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy (V.S.)
| | - Matteo Pavan
- Departments of Pharmacology & Toxicology and the Cardiovascular Center (C.L.F., T.C.W., J.A.A.) and Biochemistry and the Program in Chemical Biology (R.F.K., B.C.S.), Medical College of Wisconsin, Milwaukee, Wisconsin; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland (M.P., V.S., B.P., Z.-G.G., K.A.J.); and Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy (V.S.)
| | - Veronica Salmaso
- Departments of Pharmacology & Toxicology and the Cardiovascular Center (C.L.F., T.C.W., J.A.A.) and Biochemistry and the Program in Chemical Biology (R.F.K., B.C.S.), Medical College of Wisconsin, Milwaukee, Wisconsin; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland (M.P., V.S., B.P., Z.-G.G., K.A.J.); and Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy (V.S.)
| | - Robert F Keyes
- Departments of Pharmacology & Toxicology and the Cardiovascular Center (C.L.F., T.C.W., J.A.A.) and Biochemistry and the Program in Chemical Biology (R.F.K., B.C.S.), Medical College of Wisconsin, Milwaukee, Wisconsin; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland (M.P., V.S., B.P., Z.-G.G., K.A.J.); and Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy (V.S.)
| | - Tina C Wan
- Departments of Pharmacology & Toxicology and the Cardiovascular Center (C.L.F., T.C.W., J.A.A.) and Biochemistry and the Program in Chemical Biology (R.F.K., B.C.S.), Medical College of Wisconsin, Milwaukee, Wisconsin; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland (M.P., V.S., B.P., Z.-G.G., K.A.J.); and Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy (V.S.)
| | - Balaram Pradhan
- Departments of Pharmacology & Toxicology and the Cardiovascular Center (C.L.F., T.C.W., J.A.A.) and Biochemistry and the Program in Chemical Biology (R.F.K., B.C.S.), Medical College of Wisconsin, Milwaukee, Wisconsin; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland (M.P., V.S., B.P., Z.-G.G., K.A.J.); and Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy (V.S.)
| | - Zhan-Guo Gao
- Departments of Pharmacology & Toxicology and the Cardiovascular Center (C.L.F., T.C.W., J.A.A.) and Biochemistry and the Program in Chemical Biology (R.F.K., B.C.S.), Medical College of Wisconsin, Milwaukee, Wisconsin; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland (M.P., V.S., B.P., Z.-G.G., K.A.J.); and Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy (V.S.)
| | - Brian C Smith
- Departments of Pharmacology & Toxicology and the Cardiovascular Center (C.L.F., T.C.W., J.A.A.) and Biochemistry and the Program in Chemical Biology (R.F.K., B.C.S.), Medical College of Wisconsin, Milwaukee, Wisconsin; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland (M.P., V.S., B.P., Z.-G.G., K.A.J.); and Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy (V.S.)
| | - Kenneth A Jacobson
- Departments of Pharmacology & Toxicology and the Cardiovascular Center (C.L.F., T.C.W., J.A.A.) and Biochemistry and the Program in Chemical Biology (R.F.K., B.C.S.), Medical College of Wisconsin, Milwaukee, Wisconsin; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland (M.P., V.S., B.P., Z.-G.G., K.A.J.); and Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy (V.S.)
| | - John A Auchampach
- Departments of Pharmacology & Toxicology and the Cardiovascular Center (C.L.F., T.C.W., J.A.A.) and Biochemistry and the Program in Chemical Biology (R.F.K., B.C.S.), Medical College of Wisconsin, Milwaukee, Wisconsin; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland (M.P., V.S., B.P., Z.-G.G., K.A.J.); and Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy (V.S.)
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Gao ZG, Auchampach JA, Jacobson KA. Species dependence of A 3 adenosine receptor pharmacology and function. Purinergic Signal 2023; 19:523-550. [PMID: 36538251 PMCID: PMC9763816 DOI: 10.1007/s11302-022-09910-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 11/26/2022] [Indexed: 12/24/2022] Open
Abstract
Efforts to fully understand pharmacological differences between G protein-coupled receptor (GPCR) species homologues are generally not pursued in detail during the drug development process. To date, many GPCRs that have been successfully targeted are relatively well-conserved across species in amino acid sequence and display minimal variability of biological effects. However, the A3 adenosine receptor (AR), an exciting drug target for a multitude of diseases associated with tissue injury, ischemia, and inflammation, displays as little as 70% sequence identity among mammalian species (e.g., rodent vs. primate) commonly used in drug development. Consequently, the pharmacological properties of synthetic A3AR ligands vary widely, not only in binding affinity, selectivity, and signaling efficacy, but to the extent that some function as agonists in some species and antagonists in others. Numerous heterocyclic antagonists that have nM affinity at the human A3AR are inactive or weakly active at the rat and mouse A3ARs. Positive allosteric modulators, including the imidazo [4,5-c]quinolin-4-amine derivative LUF6000, are only active at human and some larger animal species that have been evaluated (rabbit and dog), but not rodents. A3AR agonists evoke systemic degranulation of rodent, but not human mast cells. The rat A3AR undergoes desensitization faster than the human A3AR, but the human homologue can be completely re-sensitized and recycled back to the cell surface. Thus, comprehensive pharmacological evaluation and awareness of potential A3AR species differences are critical in studies to further understand the basic biological functions of this unique AR subtype. Recombinant A3ARs from eight different species have been pharmacologically characterized thus far. In this review, we describe in detail current knowledge of species differences in genetic identity, G protein-coupling, receptor regulation, and both orthosteric and allosteric A3AR pharmacology.
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Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0810, USA.
| | - John A Auchampach
- Department of Pharmacology and Toxicology, and the Cardiovascular Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0810, USA.
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Fisher CL, Fallot LB, Wan TC, Keyes RF, Suresh RR, Rothwell AC, Gao ZG, McCorvy JD, Smith BC, Jacobson KA, Auchampach JA. Characterization of Dual-Acting A 3 Adenosine Receptor Positive Allosteric Modulators That Preferentially Enhance Adenosine-Induced Gα i3 and Gα oA Isoprotein Activation. ACS Pharmacol Transl Sci 2022; 5:625-641. [PMID: 35983277 PMCID: PMC9380209 DOI: 10.1021/acsptsci.2c00076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Indexed: 12/19/2022]
Abstract
The A3 adenosine receptor (A3AR) is a promising therapeutic target for inflammatory diseases, cancer, and chronic neuropathic pain, with agonists already in advanced clinical trials. Here we report an in-depth comparison of the pharmacological properties and structure-activity relationships of existing and expanded compound libraries of 2-substituted 1H-imidazo[4,5-c]quinolin-4-amine and 4-amino-substituted quinoline derivatives that function as A3AR positive allosteric modulators (PAMs). We also show that our lead compound from each series enhances adenosine-induced A3AR signaling preferentially toward activation of Gαi3 and GαoA isoproteins, which are coexpressed with the A3AR in immune cells and spinal cord neurons. Finally, utilizing an extracellular/intracellular chimeric A3AR approach composed of sequences from a responding (human) and a nonresponding (mouse) species, we provide evidence in support of the idea that the imidazoquinolin-4-amine class of PAMs variably interacts dually with the orthosteric ligand binding site as well as with a separate allosteric site located within the inner/intracellular regions of the receptor. This study has advanced both structural and pharmacological understanding of these two classes of A3AR PAMs, which includes leads for future pharmaceutical development.
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Affiliation(s)
- Courtney L. Fisher
- Department of Pharmacology & Toxicology and the Cardiovascular Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - Lucas B. Fallot
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
- Department of Biochemistry & Molecular Biology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814, United States
- Department of Chemistry & Life Science, United States Military Academy, 646 Swift Road, West Point, New York 10996, United States
| | - Tina C. Wan
- Department of Pharmacology & Toxicology and the Cardiovascular Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - Robert F. Keyes
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - R. Rama Suresh
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Amy C. Rothwell
- Department of Pharmacology & Toxicology and the Cardiovascular Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - John D. McCorvy
- Department of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - Brian C. Smith
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - John A. Auchampach
- Department of Pharmacology & Toxicology and the Cardiovascular Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
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Tosh DK, Salmaso V, Rao H, Campbell R, Bitant A, Gao ZG, Auchampach JA, Jacobson KA. Direct Comparison of (N)-Methanocarba and Ribose-Containing 2-Arylalkynyladenosine Derivatives as A 3 Receptor Agonists. ACS Med Chem Lett 2020; 11:1935-1941. [PMID: 33062176 DOI: 10.1021/acsmedchemlett.9b00637] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 02/07/2020] [Indexed: 12/12/2022] Open
Abstract
A side-by-side pharmacological comparison of ribose and (N)-methanocarba (bicyclo[3.1.0]hexane) nucleosides as A3AR agonists indicated that the bicyclic pseudoribose ring constraint provided higher affinity/selectivity at human and mouse A3AR. The mean affinity enhancement for 5 pairs of 5'-methylamides was 11-fold at hA3AR and 42-fold at mA3AR. Novel C2-(5-fluorothien-2-ylethynyl) substitution enhanced affinity in the methanocarba but not ribose series, with highly hA3AR-selective 16 (MRS7334) displaying Ki 280 pM and favorable pharmacokinetics and off-target activity profile. Molecular dynamics comparison of 16 and its corresponding riboside 8 suggested a qualitative entropic advantage of 16 in hA3AR binding. The 5-F substitution tended to increase hA3AR affinity (cf. 5-Cl) for methanocarba but not ribose derivatives. A representative methanocarba agonist 4 was shown to interact potently exclusively with A3AR, among 240 GPCRs and 466 kinases. Thus, despite added synthetic difficulty, the (N)-methanocarba modification has distinct advantages for A3AR agonists, which have translational potential for chronic disease treatment.
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Affiliation(s)
- Dilip K. Tosh
- Laboratory of Bioorganic Chemistry, Mouse Metabolism Core, and Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Veronica Salmaso
- Laboratory of Bioorganic Chemistry, Mouse Metabolism Core, and Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Harsha Rao
- Laboratory of Bioorganic Chemistry, Mouse Metabolism Core, and Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Ryan Campbell
- Laboratory of Bioorganic Chemistry, Mouse Metabolism Core, and Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Amelia Bitant
- Department of Pharmacology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - Zhan-Guo Gao
- Laboratory of Bioorganic Chemistry, Mouse Metabolism Core, and Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - John A. Auchampach
- Department of Pharmacology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - Kenneth A. Jacobson
- Laboratory of Bioorganic Chemistry, Mouse Metabolism Core, and Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
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Jacobson KA, Tosh DK, Jain S, Gao ZG. Historical and Current Adenosine Receptor Agonists in Preclinical and Clinical Development. Front Cell Neurosci 2019; 13:124. [PMID: 30983976 PMCID: PMC6447611 DOI: 10.3389/fncel.2019.00124] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/13/2019] [Indexed: 12/22/2022] Open
Abstract
Adenosine receptors (ARs) function in the body’s response to conditions of pathology and stress associated with a functional imbalance, such as in the supply and demand of energy/oxygen/nutrients. Extracellular adenosine concentrations vary widely to raise or lower the basal activation of four subtypes of ARs. Endogenous adenosine can correct an energy imbalance during hypoxia and other stress, for example, by slowing the heart rate by A1AR activation or increasing the blood supply to heart muscle by the A2AAR. Moreover, exogenous AR agonists, antagonists, or allosteric modulators can be applied for therapeutic benefit, and medicinal chemists working toward that goal have reported thousands of such agents. Thus, numerous clinical trials have ensued, using promising agents to modulate adenosinergic signaling, most of which have not succeeded. Currently, short-acting, parenteral agonists, adenosine and Regadenoson, are the only AR agonists approved for human use. However, new concepts and compounds are currently being developed and applied toward preclinical and clinical evaluation, and initial results are encouraging. This review focuses on key compounds as AR agonists and positive allosteric modulators (PAMs) for disease treatment or diagnosis. AR agonists for treating inflammation, pain, cancer, non-alcoholic steatohepatitis, angina, sickle cell disease, ischemic conditions and diabetes have been under development. Multiple clinical trials with two A3AR agonists are ongoing.
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Affiliation(s)
- Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Dilip K Tosh
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Shanu Jain
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
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Vecchio EA, White PJ, May LT. The adenosine A 2B G protein-coupled receptor: Recent advances and therapeutic implications. Pharmacol Ther 2019; 198:20-33. [PMID: 30677476 DOI: 10.1016/j.pharmthera.2019.01.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The adenosine A2B receptor (A2BAR) is one of four adenosine receptor subtypes belonging to the Class A family of G protein-coupled receptors (GPCRs). Until recently, the A2BAR remained poorly characterised, in part due to its relatively low affinity for the endogenous agonist adenosine and therefore presumed minor physiological significance. However, the substantial increase in extracellular adenosine concentration, the sensitisation of the receptor and the upregulation of A2BAR expression under conditions of hypoxia and inflammation, suggest the A2BAR as an exciting therapeutic target in a variety of pathological disease states. Here we discuss the pharmacology of the A2BAR and outline its role in pathophysiology including ischaemia-reperfusion injury, fibrosis, inflammation and cancer.
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Affiliation(s)
- Elizabeth A Vecchio
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia; Heart Failure Pharmacology, Baker Heart & Diabetes Institute, Melbourne, VIC 3004, Australia
| | - Paul J White
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Lauren T May
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
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Jacobson KA, Tosh DK, Jain S, Gao ZG. Historical and Current Adenosine Receptor Agonists in Preclinical and Clinical Development. Front Cell Neurosci 2019. [PMID: 30983976 DOI: 10.3389/fncel.2019.00124/bibtex] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Adenosine receptors (ARs) function in the body's response to conditions of pathology and stress associated with a functional imbalance, such as in the supply and demand of energy/oxygen/nutrients. Extracellular adenosine concentrations vary widely to raise or lower the basal activation of four subtypes of ARs. Endogenous adenosine can correct an energy imbalance during hypoxia and other stress, for example, by slowing the heart rate by A1AR activation or increasing the blood supply to heart muscle by the A2AAR. Moreover, exogenous AR agonists, antagonists, or allosteric modulators can be applied for therapeutic benefit, and medicinal chemists working toward that goal have reported thousands of such agents. Thus, numerous clinical trials have ensued, using promising agents to modulate adenosinergic signaling, most of which have not succeeded. Currently, short-acting, parenteral agonists, adenosine and Regadenoson, are the only AR agonists approved for human use. However, new concepts and compounds are currently being developed and applied toward preclinical and clinical evaluation, and initial results are encouraging. This review focuses on key compounds as AR agonists and positive allosteric modulators (PAMs) for disease treatment or diagnosis. AR agonists for treating inflammation, pain, cancer, non-alcoholic steatohepatitis, angina, sickle cell disease, ischemic conditions and diabetes have been under development. Multiple clinical trials with two A3AR agonists are ongoing.
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Affiliation(s)
- Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Dilip K Tosh
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Shanu Jain
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
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Ni Y, Liang D, Tian Y, Kron IL, French BA, Yang Z. Infarct-Sparing Effect of Adenosine A2B Receptor Agonist Is Primarily Due to Its Action on Splenic Leukocytes Via a PI3K/Akt/IL-10 Pathway. J Surg Res 2018; 232:442-449. [PMID: 30463755 DOI: 10.1016/j.jss.2018.06.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 05/18/2018] [Accepted: 06/14/2018] [Indexed: 01/18/2023]
Abstract
BACKGROUND Adenosine A2B receptor (A2BAR) agonist reduces myocardial reperfusion injury by acting on inflammatory cells. Recently, a cardiosplenic axis was shown to mediate the myocardial postischemic reperfusion injury. This study aimed to explore whether the infarct-squaring effect of A2BAR agonist was primarily due to its action on splenic leukocytes. METHODS C57BL6 (wild type [WT]) mice underwent 40 min of left coronary artery occlusion followed by 60 min of reperfusion. A2BAR knockout (KO) and interleukin (IL)-10KO mice served as donors for splenic leukocytes. Acute splenectomy was performed 30 min before ischemia. The acute splenic leukocyte adoptive transfer was performed by injecting 5 × 106 live splenic leukocytes into splenectomized mice. BAY 60-6583, an A2BAR agonist, was injected by i.v. 15 min before ischemia. The infarct size (IS) was determined using 2,3,5-triphenyltetrazolium chloride and Phthalo blue staining. The expression of p-Akt and IL-10 was estimated by Western blotting. Immunofluorescence staining assessed the localization of IL-10 expression. RESULTS BAY 60-6583 reduced the myocardial IS in intact mice but failed to reduce the same in splenectomized mice, which had a smaller IS than intact mice. BAY 60-6583 reduced the IS in splenectomized mice with the acute transfer of WT splenic leukocytes; however, it did not protect the heart of splenectomized mice with the acute transfer of A2BRKO splenic leukocytes. Furthermore, BAY 60-6583 increased the levels of p-Akt and IL-10 in the WT spleen. Moreover, it did not exert any protective effect in IL-10KO mice. CONCLUSIONS A2BAR activation before ischemia stimulated the IL-10 production in splenic leukocytes via a PI3K/Akt pathway, thereby exerting anti-inflammatory effects that limited the myocardial reperfusion injury.
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Affiliation(s)
- Yingying Ni
- Department of Cardiovascular Surgery, Tianjin Medical University General Hospital, Tianjin, P.R. of China
| | - Degang Liang
- Department of Cardiovascular Surgery, Tianjin Medical University General Hospital, Tianjin, P.R. of China
| | - Yikui Tian
- Department of Cardiovascular Surgery, Tianjin Medical University General Hospital, Tianjin, P.R. of China.
| | - Irving L Kron
- Department of Surgery, University of Virginia Health System, Charlottesville, Virginia
| | - Brent A French
- Department of Biomedical Engineering, University of Virginia Health System, Charlottesville, Virginia
| | - Zequan Yang
- Department of Surgery, University of Virginia Health System, Charlottesville, Virginia.
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Gao ZG, Inoue A, Jacobson KA. On the G protein-coupling selectivity of the native A 2B adenosine receptor. Biochem Pharmacol 2018; 151:201-213. [PMID: 29225130 PMCID: PMC5899946 DOI: 10.1016/j.bcp.2017.12.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 12/05/2017] [Indexed: 12/14/2022]
Abstract
A2B adenosine receptor (A2BAR) activation induces Gs-dependent cyclic AMP accumulation. However, A2BAR G protein-coupling to other signaling events, e.g. ERK1/2 and calcium, is not well documented. We explored Gi, Gq/11 and Gs coupling in 1321 N1 astrocytoma, HEK293, and T24 bladder cancer cells endogenously expressing human A2BAR, using NECA or nonnucleoside BAY60-6583 as agonist, selective Gi, Gs and Gq/11 blockers, and CRISPR/Cas9-based Gq- and Gs-null HEK293 cells. In HEK293 cells, A2BAR-mediated ERK1/2 activity occurred via both Gi and Gs, but not Gq/11. However, HEK293 cell calcium mobilization was completely blocked by Gq/11 inhibitor UBO-QIC and by Gq/11 knockout. In T24 cells, Gi was solely responsible for A2BAR-mediated ERK1/2 stimulation, and Gs suppressed ERK1/2 activity. A2BAR-mediated intracellular calcium mobilization in T24 cells was mainly via Gi, although Gs may also play a role, but Gq/11 is not involved. In 1321 N1 astrocytoma cells A2BAR activation suppressed rather than stimulated ERK1/2 activity. The ERK1/2 activity decrease was reversed by Gs downregulation using cholera toxin, but potentiated by Gi inhibitor pertussis toxin, and UBO-QIC had no effect. EPACs played an important role in A2BAR-mediated ERK1/2 signaling in all three cells. Thus, A2BAR may: couple to the same downstream pathway via different G proteins in different cell types; activate different downstream events via different G proteins in the same cell type; activate Gi and Gs, which have opposing or synergistic roles in different cell types/signaling pathways. The findings, relevant to drug discovery, address some reported controversial roles of A2BAR and could apply to signaling mechanisms in other GPCRs.
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Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.
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10
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Sarkar B, Maiti S, Jadhav GR, Paira P. Discovery of benzothiazolylquinoline conjugates as novel human A 3 receptor antagonists: biological evaluations and molecular docking studies. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171622. [PMID: 29515874 PMCID: PMC5830763 DOI: 10.1098/rsos.171622] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 01/08/2018] [Indexed: 03/16/2024]
Abstract
Adenosine is known as an endogenous purine nucleoside and it modulates a wide variety of physiological responses by interacting with adenosine receptors. Among the four adenosine receptor subtypes, the A3 receptor is of major interest in this study as it is overexpressed in some cancer cell lines. Herein, we have highlighted the strategy of designing the hA3 receptor targeted novel benzothiazolylquinoline scaffolds. The radioligand binding data of the reported compounds are rationalized with the molecular docking results. Compound 6a showed best potency and selectivity at hA3 among other adenosine receptors.
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Affiliation(s)
| | | | | | - Priyankar Paira
- Department of Chemistry, School of Advanced Sciences, VIT University, Vellore, Tamil Nadu 632014, India
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11
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Gao ZG, Jacobson KA. Purinergic Signaling in Mast Cell Degranulation and Asthma. Front Pharmacol 2017; 8:947. [PMID: 29311944 PMCID: PMC5744008 DOI: 10.3389/fphar.2017.00947] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 12/14/2017] [Indexed: 11/13/2022] Open
Abstract
Mast cells are responsible for the majority of allergic conditions. It was originally thought that almost all allergic events were mediated directly only via the high-affinity immunoglobulin E receptors. However, recent evidence showed that many other receptors, such as G protein-coupled receptors and ligand-gated ion channels, are also directly involved in mast cell degranulation, the release of inflammatory mediators such as histamine, serine proteases, leukotrienes, heparin, and serotonin. These mediators are responsible for the symptoms in allergic conditions such as allergic asthma. In recent years, it has been realized that purinergic signaling, induced via the activation of G protein-coupled adenosine receptors and P2Y nucleotide receptors, as well as by ATP-gated P2X receptors, plays a significant role in mast cell degranulation. Both adenosine and ATP can induce degranulation and bronchoconstriction on their own and synergistically with allergens. All three classes of receptors, adenosine, P2X and P2Y are involved in tracheal mucus secretion. This review will summarize the currently available knowledge on the role of purinergic signaling in mast cell degranulation and its most relevant disease, asthma.
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Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
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12
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Du L, Gao ZG, Paoletta S, Wan TC, Gizewski ET, Barbour S, van Veldhoven JPD, IJzerman AP, Jacobson KA, Auchampach JA. Species differences and mechanism of action of A 3 adenosine receptor allosteric modulators. Purinergic Signal 2017; 14:59-71. [PMID: 29170977 DOI: 10.1007/s11302-017-9592-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 11/01/2017] [Indexed: 02/01/2023] Open
Abstract
Activity of the A3 adenosine receptor (AR) allosteric modulators LUF6000 (2-cyclohexyl-N-(3,4-dichlorophenyl)-1H-imidazo [4,5-c]quinolin-4-amine) and LUF6096 (N-{2-[(3,4-dichlorophenyl)amino]quinolin-4-yl}cyclohexanecarbox-amide) was compared at four A3AR species homologs used in preclinical drug development. In guanosine 5'-[γ-[35S]thio]triphosphate ([35S]GTPγS) binding assays with cell membranes isolated from human embryonic kidney cells stably expressing recombinant A3ARs, both modulators substantially enhanced agonist efficacy at human, dog, and rabbit A3ARs but provided only weak activity at mouse A3ARs. For human, dog, and rabbit, both modulators increased the maximal efficacy of the A3AR agonist 2-chloro-N 6-(3-iodobenzyl)adenosine-5'-N-methylcarboxamide as well as adenosine > 2-fold, while slightly reducing potency in human and dog. Based on results from N 6-(4-amino-3-[125I]iodobenzyl)adenosine-5'-N-methylcarboxamide ([125I]I-AB-MECA) binding assays, we hypothesize that potency reduction is explained by an allosterically induced slowing in orthosteric ligand binding kinetics that reduces the rate of formation of ligand-receptor complexes. Mutation of four amino acid residues of the human A3AR to the murine sequence identified the extracellular loop 1 (EL1) region as being important in selectively controlling the allosteric actions of LUF6096 on [125I]I-AB-MECA binding kinetics. Homology modeling suggested interaction between species-variable EL1 and agonist-contacting EL2. These results indicate that A3AR allostery is species-dependent and provide mechanistic insights into this therapeutically promising class of agents.
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Affiliation(s)
- Lili Du
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 200892-0810, USA
| | - Silvia Paoletta
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 200892-0810, USA
| | - Tina C Wan
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Elizabeth T Gizewski
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Samantha Barbour
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Jacobus P D van Veldhoven
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, PO Box 9502, 2300 RA, Leiden, The Netherlands
| | - Adriaan P IJzerman
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, PO Box 9502, 2300 RA, Leiden, The Netherlands
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 200892-0810, USA
| | - John A Auchampach
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
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13
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Basu S, Barawkar DA, Ramdas V, Patel M, Waman Y, Panmand A, Kumar S, Thorat S, Naykodi M, Goswami A, Reddy BS, Prasad V, Chaturvedi S, Quraishi A, Menon S, Paliwal S, Kulkarni A, Karande V, Ghosh I, Mustafa S, De S, Jain V, Banerjee ER, Rouduri SR, Palle VP, Chugh A, Mookhtiar KA. Design and synthesis of novel xanthine derivatives as potent and selective A 2B adenosine receptor antagonists for the treatment of chronic inflammatory airway diseases. Eur J Med Chem 2017; 134:218-229. [PMID: 28415011 DOI: 10.1016/j.ejmech.2017.04.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 04/01/2017] [Accepted: 04/07/2017] [Indexed: 10/19/2022]
Abstract
Adenosine induces bronchial hyperresponsiveness and inflammation in asthmatics through activation of A2B adenosine receptor (A2BAdoR). Selective antagonists have been shown to attenuate airway reactivity and improve inflammatory conditions in pre-clinical studies. Hence, the identification of novel, potent and selective A2BAdoR antagonist may be beneficial for the potential treatment of asthma and Chronic Obstructive Pulmonary Disease (COPD). Towards this effort, we explored several prop-2-ynylated C8-aryl or heteroaryl substitutions on xanthine chemotype and found that 1-prop-2-ynyl-1H-pyrazol-4-yl moiety was better tolerated at the C8 position. Compound 59, exhibited binding affinity (Ki) of 62 nM but was non-selective for A2BAdoR over other AdoRs. Incorporation of substituted phenyl on the terminal acetylene increased the binding affinity (Ki) significantly to <10 nM. Various substitutions on terminal phenyl group and different alkyl substitutions on N-1 and N-3 were explored to improve the potency, selectivity for A2BAdoR and the solubility. In general, compounds with meta-substituted phenyl provided better selectivity for A2BAdoR compared to that of para-substituted analogs. Substitutions such as basic amines like pyrrolidine, piperidine, piperazine or cycloalkyls with polar group were tried on terminal acetylene, keeping in mind the poor solubility of xanthine analogs in general. However, these substitutions led to a decrease in affinity compared to compound 59. Subsequent SAR optimization resulted in identification of compound 46 with high human A2BAdoR affinity (Ki = 13 nM), selectivity against other AdoR subtypes and with good pharmacokinetic properties. It was found to be a potent functional A2BAdoR antagonist with a Ki of 8 nM in cAMP assay in hA2B-HEK293 cells and an IC50 of 107 nM in IL6 assay in NIH-3T3 cells. Docking study was performed to rationalize the observed affinity data. Structure-activity relationship (SAR) studies also led to identification of compound 36 as a potent A2BAdoR antagonist with Ki of 1.8 nM in cAMP assay and good aqueous solubility of 529 μM at neutral pH. Compound 46 was further tested for in vivo efficacy and found to be efficacious in ovalbumin-induced allergic asthma model in mice.
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Affiliation(s)
- Sujay Basu
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India.
| | - Dinesh A Barawkar
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Vidya Ramdas
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Meena Patel
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Yogesh Waman
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Anil Panmand
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Santosh Kumar
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Sachin Thorat
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Minakshi Naykodi
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Arnab Goswami
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - B Srinivasa Reddy
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Vandna Prasad
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Sandhya Chaturvedi
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Azfar Quraishi
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Suraj Menon
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Shalini Paliwal
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Abhay Kulkarni
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Vikas Karande
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Indraneel Ghosh
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Syed Mustafa
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Siddhartha De
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Vaibhav Jain
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Ena Ray Banerjee
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Sreekanth R Rouduri
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Venkata P Palle
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Anita Chugh
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India
| | - Kasim A Mookhtiar
- Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plot-9, Phase-I, Rajiv Gandhi Infotech Park, Hinjawadi, Pune 411 057, India.
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14
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Singh J, Shah R, Singh D. Inundation of asthma target research: Untangling asthma riddles. Pulm Pharmacol Ther 2016; 41:60-85. [PMID: 27667568 DOI: 10.1016/j.pupt.2016.09.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 08/11/2016] [Accepted: 09/20/2016] [Indexed: 12/31/2022]
Abstract
Asthma is an inveterate inflammatory disorder, delineated by the airway inflammation, bronchial hyperresponsiveness (BHR) and airway wall remodeling. Although, asthma is a vague term, and is recognized as heterogenous entity encompassing different phenotypes. Targeting single mediator or receptor did not prove much clinical significant, as asthma is complex disease involving myriad inflammatory mediators. Asthma may probably involve a large number of different types of molecular and cellular components interacting through complex pathophysiological pathways. This review covers the past, present, and future therapeutic approaches and pathophysiological mechanisms of asthma. Furthermore, review describe importance of targeting several mediators/modulators and receptor antagonists involved in the physiopathology of asthma. Novel targets for asthma research include Galectins, Immunological targets, K + Channels, Kinases and Transcription Factors, Toll-like receptors, Selectins and Transient receptor potential channels. But recent developments in asthma research are very promising, these include Bitter taste receptors (TAS2R) abated airway obstruction in mouse model of asthma and Calcium-sensing receptor obliterate inflammation and in bronchial hyperresponsiveness allergic asthma. All these progresses in asthma targets, and asthma phenotypes exploration are auspicious in untangling of asthma riddles.
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Affiliation(s)
- Jatinder Singh
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, 147002, Punjab, India
| | - Ramanpreet Shah
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, 147002, Punjab, India
| | - Dhandeep Singh
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, 147002, Punjab, India.
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15
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Abstract
Cellular stress or apoptosis triggers the release of ATP, ADP and other nucleotides into the extracellular space. Extracellular nucleotides function as autocrine and paracrine signalling molecules by activating cell-surface P2 purinergic receptors that elicit pro-inflammatory immune responses. Over time, extracellular nucleotides are metabolized to adenosine, leading to reduced P2 signalling and increased signalling through anti-inflammatory adenosine (P1 purinergic) receptors. Here, we review how local purinergic signalling changes over time during tissue responses to injury or disease, and we discuss the potential of targeting purinergic signalling pathways for the immunotherapeutic treatment of ischaemia, organ transplantation, autoimmunity or cancer.
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Affiliation(s)
- Caglar Cekic
- Department of Molecular Biology and Genetics, Bilkent University, Ankara 06800, Turkey
| | - Joel Linden
- Division of Developmental Immunology, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA
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16
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Pei H, Linden J. Adenosine influences myeloid cells to inhibit aeroallergen sensitization. Am J Physiol Lung Cell Mol Physiol 2016; 310:L985-92. [PMID: 27016586 DOI: 10.1152/ajplung.00330.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 03/21/2016] [Indexed: 12/13/2022] Open
Abstract
Agonists of adenosine A2A receptors (A2ARs) suppress the activation of most immune cells and reduce acute inflammatory responses. Asthma is characterized by sensitization in response to initial allergen exposure and by airway hyperreactivity in response to allergen rechallenge. We sought to determine if A2AR activation with CGS-21680 (CGS) is more effective when CGS is administered during sensitization or rechallenge. C57BL/6 wild-type mice and Adora2a(f/f)LysMCre(+/-) mice, which lack A2ARs on myeloid cells, were sensitized with intranasal ovalbumin (OVA) and LPS. Airway sensitization was characterized by a rapid increase in numbers of IL-6(+) and IL-12(+) macrophages and dendritic cells in lungs. A2AR activation with CGS (0.1 μg·kg(-1)·min(-1) sc) only during sensitization reduced numbers of IL-6(+) and IL-12(+) myeloid cells in the lungs and reversed the effects of OVA rechallenge to increase airway hyperresponsiveness to methacholine. CGS treatment during sensitization also reduced the expansion of lung T helper (Th1 and Th17) cells and increased expansion of regulatory T cells in response to OVA rechallenge. Most of the effects of CGS administered during sensitization were eliminated by myeloid-selective A2AR deletion. Administration of CGS only during OVA rechallenge failed to reduce airway hyperresponsiveness. We conclude that myeloid cells are key targets of adenosine during sensitization and indirectly modify T cell polarization. The results suggest that a clinically useful strategy might be to use A2AR agonists to inhibit sensitization to new aeroallergens. We speculate that adenosine production by macrophages engulfing bacteria contributes to the curious suppression of sensitization in response to early-life infections.
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Affiliation(s)
- Hong Pei
- Division of Developmental Immunology, La Jolla Institute for Allergy and Immunology, La Jolla, California
| | - Joel Linden
- Division of Developmental Immunology, La Jolla Institute for Allergy and Immunology, La Jolla, California
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17
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Shaikh G, Cronstein B. Signaling pathways involving adenosine A2A and A2B receptors in wound healing and fibrosis. Purinergic Signal 2016; 12:191-7. [PMID: 26847815 DOI: 10.1007/s11302-016-9498-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 01/27/2016] [Indexed: 02/07/2023] Open
Abstract
Collagen and matrix deposition by fibroblasts is an essential part of wound healing but also contributes to pathologic remodeling of organs leading to substantial morbidity and mortality. Adenosine, a small molecule generated extracellularly from adenine nucleotides as a result of direct stimulation, hypoxia, or injury, acts via a family of classical seven-pass G protein-coupled protein receptors, A2A and A2B, leading to generation of cAMP and activation of downstream targets such as PKA and Epac. These effectors, in turn, lead to fibroblast activation and collagen synthesis. The regulatory actions of these receptors likely involve multiple interconnected pathways, and one of the more interesting aspects of this regulation is opposing effects at different levels of cAMP generated. Additionally, adenosine signaling contributes to fibrosis in organ-specific ways and may have opposite effects in different organs. The development of drugs that selectively target these receptors and their signaling pathways will disrupt the pathogenesis of fibrosis and slow or arrest the progression of the important diseases they underlie.
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Affiliation(s)
- Gibran Shaikh
- Department of Medicine, New York University School of Medicine, 227 East 30th Street, New York, NY, 10016, USA
| | - Bruce Cronstein
- Department of Medicine, New York University School of Medicine, 227 East 30th Street, New York, NY, 10016, USA.
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18
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Federico S, Ciancetta A, Porta N, Redenti S, Pastorin G, Cacciari B, Klotz KN, Moro S, Spalluto G. 5,7-Disubstituted-[1,2,4]triazolo[1,5-a][1,3,5]triazines as pharmacological tools to explore the antagonist selectivity profiles toward adenosine receptors. Eur J Med Chem 2015; 108:529-541. [PMID: 26717203 DOI: 10.1016/j.ejmech.2015.12.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 12/03/2015] [Accepted: 12/10/2015] [Indexed: 10/22/2022]
Abstract
The structure-activity relationship of new 5,7-disubstituted-[1,2,4]triazolo[1,5-a][1,3,5]triazines as adenosine receptors (ARs) antagonists has been explored. The introduction of a benzylamino group at C5 with a free amino group at C7 increases the affinity toward all the ARs subtypes (10: KihA1 = 94.6 nM; KihA2A = 1.11 nM; IC50hA2B = 2214 nM; KihA3 = 30.8 nM). Replacing the free amino group at C7 with a phenylureido moiety yields a potent and quite selective hA2A AR antagonist (14: hA2A AR Ki = 1.44 nM; hA1/hA2A = 216.0; hA3/hA2A = 20.6). This trend diverges from the analysis on the pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine series previously reported. With the help of an in silico receptor-driven approach, we have rationalized these observations and elucidated from a molecular point of view the role of the benzylamino group at C5 in determining affinity toward the hA2A AR.
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Affiliation(s)
- Stephanie Federico
- Dipartimento di Scienze Chimiche e Farmaceutiche, Università di Trieste, Piazzale Europa 1, 34127 Trieste, Italy
| | - Antonella Ciancetta
- Molecular Modeling Section (MMS), Dipartimento di Scienze del Farmaco, Università di Padova, Via Marzolo 5, 35131 Padova, Italy
| | - Nicola Porta
- Molecular Modeling Section (MMS), Dipartimento di Scienze del Farmaco, Università di Padova, Via Marzolo 5, 35131 Padova, Italy
| | - Sara Redenti
- Dipartimento di Scienze Chimiche e Farmaceutiche, Università di Trieste, Piazzale Europa 1, 34127 Trieste, Italy
| | - Giorgia Pastorin
- Department of Pharmacy, National University of Singapore, 3 Science Drive 2, 117543 Singapore
| | - Barbara Cacciari
- Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Ferrara, Via Fossato di Mortara 17-19, 44100 Ferrara, Italy
| | - Karl Norbert Klotz
- Institut für Pharmakologie und Toxicologie, Universität of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany
| | - Stefano Moro
- Molecular Modeling Section (MMS), Dipartimento di Scienze del Farmaco, Università di Padova, Via Marzolo 5, 35131 Padova, Italy.
| | - Giampiero Spalluto
- Dipartimento di Scienze Chimiche e Farmaceutiche, Università di Trieste, Piazzale Europa 1, 34127 Trieste, Italy.
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19
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Burnstock G, Boeynaems JM. Purinergic signalling and immune cells. Purinergic Signal 2014; 10:529-64. [PMID: 25352330 PMCID: PMC4272370 DOI: 10.1007/s11302-014-9427-2] [Citation(s) in RCA: 218] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 09/12/2013] [Indexed: 11/28/2022] Open
Abstract
This review article provides a historical perspective on the role of purinergic signalling in the regulation of various subsets of immune cells from early discoveries to current understanding. It is now recognised that adenosine 5'-triphosphate (ATP) and other nucleotides are released from cells following stress or injury. They can act on virtually all subsets of immune cells through a spectrum of P2X ligand-gated ion channels and G protein-coupled P2Y receptors. Furthermore, ATP is rapidly degraded into adenosine by ectonucleotidases such as CD39 and CD73, and adenosine exerts additional regulatory effects through its own receptors. The resulting effect ranges from stimulation to tolerance depending on the amount and time courses of nucleotides released, and the balance between ATP and adenosine. This review identifies the various receptors involved in the different subsets of immune cells and their effects on the function of these cells.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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Leung CT, Li A, Banerjee J, Gao ZG, Kambayashi T, Jacobson KA, Civan MM. The role of activated adenosine receptors in degranulation of human LAD2 mast cells. Purinergic Signal 2014; 10:465-75. [PMID: 24595664 PMCID: PMC4152452 DOI: 10.1007/s11302-014-9409-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 01/28/2014] [Indexed: 01/01/2023] Open
Abstract
Mast cell degranulation triggers hypersensitivity reactions at the body-environment interface. Adenosine modulates degranulation, but enhancement and inhibition have both been reported. Which of four adenosine receptors (ARs) mediate modulation, and how, remains uncertain. Also uncertain is whether adenosine reaches mast cell ARs by autocrine ATP release and ecto-enzymatic conversion. Uncertainties partly reflect species and cell heterogeneity, circumvented here by focusing on homogeneous human LAD2 cells. Quantitative PCR detected expression of A2A, A2B, and A3, but not A1, ARs. Nonselective activation of ARs with increasing NECA monotonically enhanced immunologically or C3a-stimulated degranulation. NECA alone stimulated degranulation slightly. Selective AR antagonists did not affect C3a-stimulated degranulation. NECA's enhancement of C3a-triggered degranulation was partially inhibited by separate application of each selective antagonist, and abolished by simultaneous addition of antagonists to the three ARs. Only the A2A antagonist separately inhibited NECA's enhancement of immunologically stimulated degranulation, which was abolished by simultaneous addition of the three selective antagonists. Immunological or C3a activation did not stimulate ATP release. NECA also enhanced immunologically triggered degranulation of mouse bone marrow derived mast cells (BMMCs), which was partially reduced only by simultaneous addition of the three antagonists or by the nonselective antagonist CGS15943. BMMCs also expressed A2A, A2B, and A3 ARs. but not A1AR detectably. We conclude that (a) A1AR is unnecessary for LAD2 degranulation or AR enhancement; (b) A2A, A2B, and A3 ARs all contribute to pharmacologic AR enhancement of LAD2 and BMMC degranulation; and (c) LAD2 cells depend on microenvironmental adenosine to trigger AR modulation.
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Affiliation(s)
- Chi Ting Leung
- />Department of Physiology, University of Pennsylvania School of Medicine, A303 Richards Building, Philadelphia, PA 19104-6085 USA
| | - Ang Li
- />Department of Physiology, University of Pennsylvania School of Medicine, A303 Richards Building, Philadelphia, PA 19104-6085 USA
- />Department of Anatomy, University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong, SAR People’s Republic of China
- />Department of Medicine, University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong, SAR People’s Republic of China
| | - Juni Banerjee
- />Department of Physiology, University of Pennsylvania School of Medicine, A303 Richards Building, Philadelphia, PA 19104-6085 USA
| | - Zhan-Guo Gao
- />Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, MD USA
| | - Taku Kambayashi
- />Department of Pathology & Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA USA
| | - Kenneth A. Jacobson
- />Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, MD USA
| | - Mortimer M. Civan
- />Department of Physiology, University of Pennsylvania School of Medicine, A303 Richards Building, Philadelphia, PA 19104-6085 USA
- />Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA USA
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21
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Greenland JR, Xu X, Sayah DM, Liu FC, Jones KD, Looney MR, Caughey GH. Mast cells in a murine lung ischemia-reperfusion model of primary graft dysfunction. Respir Res 2014; 15:95. [PMID: 25115556 PMCID: PMC4151192 DOI: 10.1186/s12931-014-0095-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 08/04/2014] [Indexed: 01/21/2023] Open
Abstract
Primary graft dysfunction (PGD), as characterized by pulmonary infiltrates and high oxygen requirements shortly after reperfusion, is the major cause of early morbidity and mortality after lung transplantation. Donor, recipient and allograft-handling factors are thought to contribute, although new insights regarding pathogenesis are needed to guide approaches to prevention and therapy. Mast cells have been implicated in ischemic tissue injury in other model systems and in allograft rejection, leading to the hypothesis that mast cell degranulation contributes to lung injury following reperfusion injury. We tested this hypothesis in a mouse model of PGD involving reversible disruption of blood flow to one lung. Metrics of injury included albumin permeability, plasma extravasation, lung histopathology, and mast cell degranulation. Responses were assessed in wild-type (Kit+/+) and mast cell-deficient (KitW-sh/W-sh) mice. Because mouse lungs have few mast cells compared with human lungs, we also tested responses in mice with lung mastocytosis generated by injecting bone marrow-derived cultured mast cells (BMCMC). We found that ischemic lung responses of mast cell-deficient KitW-sh/W-sh mice did not differ from those of Kit+/+ mice, even after priming for injury using LPS. Degranulated mast cells were more abundant in ischemic than in non-ischemic BMCMC-injected KitW-sh/W-sh lungs. However, lung injury in BMCMC-injected KitW-sh/W-sh and Kit+/+ mice did not differ in globally mast cell-deficient, uninjected KitW-sh/W-sh mice or in wild-type Kit+/+ mice relatively deficient in lung mast cells. These findings predict that mast cells, although activated in lungs injured by ischemia and reperfusion, are not necessary for the development of PGD.
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Dal Ben D, Buccioni M, Lambertucci C, Thomas A, Klotz KN, Federico S, Cacciari B, Spalluto G, Volpini R. 8-(2-Furyl)adenine derivatives as A₂A adenosine receptor ligands. Eur J Med Chem 2013; 70:525-35. [PMID: 24189496 DOI: 10.1016/j.ejmech.2013.10.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 10/03/2013] [Indexed: 11/19/2022]
Abstract
Selective adenosine receptor modulators are potential tools for numerous therapeutic applications, including cardiovascular, inflammatory, and neurodegenerative diseases. In this work, the synthesis and biological evaluation at the four human adenosine receptor subtypes of a series of 9-substituted 8-(2-furyl)adenine derivatives are reported. Results show that 8-(2-furyl)-9-methyladenine is endowed with high affinity at the A₂A subtype. Further modification of this compound with introduction of arylacetyl or arylcarbamoyl groups in N(6)-position takes to different effects on the A₂A affinity and in particular on the selectivity versus the other three adenosine receptor subtypes. A molecular modelling analysis at three different A₂A receptor crystal structures provides an interpretation of the obtained biological results.
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Affiliation(s)
- Diego Dal Ben
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, Via S. Agostino 1, I-62032 Camerino, MC, Italy
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23
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Ryzhov S, Biktasova A, Goldstein AE, Zhang Q, Biaggioni I, Dikov MM, Feoktistov I. Role of JunB in adenosine A2B receptor-mediated vascular endothelial growth factor production. Mol Pharmacol 2013; 85:62-73. [PMID: 24136993 DOI: 10.1124/mol.113.088567] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Interstitial adenosine stimulates neovascularization in part through A2B adenosine receptor-dependent upregulation of vascular endothelial growth factor (VEGF). In the current study, we tested the hypothesis that A2B receptors upregulate JunB, which can contribute to stimulation of VEGF production. Using the human microvascular endothelial cell line, human mast cell line, mouse cardiac Sca1-positive stromal cells, and mouse Lewis lung carcinoma (LLC) cells, we found that adenosine receptor-dependent upregulation of VEGF production was associated with an increase in VEGF transcription, activator protein-1 (AP-1) activity, and JunB accumulation in all cells investigated. Furthermore, the expression of JunB, but not the expression of other genes encoding transcription factors from the Jun family, was specifically upregulated. In LLC cells expressing A2A and A2B receptor transcripts, only the nonselective adenosine agonist NECA (5'-N-ethylcarboxamidoadenosine), but not the selective A2A receptor agonist CGS21680 [2-p-(2-carboxyethyl) phenylethylamino-5'-N-ethylcarboxamidoadenosine], significantly increased JunB reporter activity and JunB nuclear accumulation, which were inhibited by the A2B receptor antagonist PSB603 [(8-[4-[4-((4-chlorophenzyl)piperazide-1-sulfonyl)phenyl]]-1-propylxanthine]. Using activators and inhibitors of intracellular signaling, we demonstrated that A2B receptor-dependent accumulation of JunB protein and VEGF secretion share common intracellular pathways. NECA enhanced JunB binding to the murine VEGF promoter, whereas mutation of the high-affinity AP-1 site (-1093 to -1086) resulted in a loss of NECA-dependent VEGF reporter activity. Finally, NECA-dependent VEGF secretion and reporter activity were inhibited by the expression of a dominant negative JunB or by JunB knockdown. Thus, our data suggest an important role of the A2B receptor-dependent upregulation of JunB in VEGF production and possibly other AP-1-regulated events.
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Affiliation(s)
- Sergey Ryzhov
- Divisions of Cardiovascular Medicine (S.R., Q.Z., I.F.) and Clinical Pharmacology (A.E.G., I.B.), and Departments of Cancer Biology (A.B., M.M.D.), Medicine (S.R., A.E.G., Q.Z., I.B., I.F.), and Pharmacology (I.B., I.F.), Vanderbilt University, Nashville, Tennessee
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24
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Bacilieri M, Ciancetta A, Paoletta S, Federico S, Cosconati S, Cacciari B, Taliani S, Da Settimo F, Novellino E, Klotz KN, Spalluto G, Moro S. Revisiting a receptor-based pharmacophore hypothesis for human A(2A) adenosine receptor antagonists. J Chem Inf Model 2013; 53:1620-37. [PMID: 23705857 DOI: 10.1021/ci300615u] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The application of both structure- and ligand-based design approaches represents to date one of the most useful strategies in the discovery of new drug candidates. In the present paper, we investigated how the application of docking-driven conformational analysis can improve the predictive ability of 3D-QSAR statistical models. With the use of the crystallographic structure in complex with the high affinity antagonist ZM 241385 (4-(2-[7-amino-2-(2-furyl)[1,2,4]-triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol), we revisited a general pharmacophore hypothesis for the human A(2A) adenosine receptor of a set of 751 known antagonists, by applying an integrated ligand- and structure-based approach. Our novel pharmacophore hypothesis has been validated by using an external test set of 29 newly synthesized human adenosine receptor antagonists.
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Affiliation(s)
- Magdalena Bacilieri
- Molecular Modeling Section-MMS, Dipartimento di Scienze del Farmaco, Università di Padova, Via Marzolo 5, Padova, Italy
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25
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Adenosine A1 receptors heterodimerize with β1- and β2-adrenergic receptors creating novel receptor complexes with altered G protein coupling and signaling. Cell Signal 2013; 25:736-42. [PMID: 23291003 DOI: 10.1016/j.cellsig.2012.12.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 12/17/2012] [Accepted: 12/21/2012] [Indexed: 11/20/2022]
Abstract
G protein coupled receptors play crucial roles in mediating cellular responses to external stimuli, and increasing evidence suggests that they function as multiple units comprising homo/heterodimers and hetero-oligomers. Adenosine and β-adrenergic receptors are co-expressed in numerous tissues and mediate important cellular responses to the autocoid adenosine and sympathetic stimulation, respectively. The present study was undertaken to examine whether adenosine A1ARs heterodimerize with β1- and/or β2-adrenergic receptors (β1R and β2R), and whether such interactions lead to functional consequences. Co-immunoprecipitation and co-localization studies with differentially epitope-tagged A1, β1, and β2 receptors transiently co-expressed in HEK-293 cells indicate that A1AR forms constitutive heterodimers with both β1R and β2R. This heterodimerization significantly influenced orthosteric ligand binding affinity of both β1R and β2R without altering ligand binding properties of A1AR. Receptor-mediated ERK1/2 phosphorylation significantly increased in cells expressing A1AR/β1R and A1AR/β2R heteromers. β-Receptor-mediated cAMP production was not altered in A1AR/β1R expressing cells, but was significantly reduced in the A1AR/β2R cells. The inhibitory effect of the A1AR on cAMP production was abrogated in both A1AR/β1R and A1AR/β2R expressing cells in response to the A1AR agonist CCPA. Co-immunoprecipitation studies conducted with human heart tissue lysates indicate that endogenous A1AR, β1R, and β2R also form heterodimers. Taken together, our data suggest that heterodimerization between A1 and β receptors leads to altered receptor pharmacology, functional coupling, and intracellular signaling pathways. Unique and differential receptor cross-talk between these two important receptor families may offer the opportunity to fine-tune crucial signaling responses and development of more specific therapeutic interventions.
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26
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Lim JC, Mitchell CH. Inflammation, pain, and pressure--purinergic signaling in oral tissues. J Dent Res 2012; 91:1103-9. [PMID: 23042126 DOI: 10.1177/0022034512463239] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Signaling by extracellular purines such as ATP and adenosine has implications for dental research on multiple levels, with the association of purinergic signaling with inflammation, mechanical strain, and pain making the system particularly relevant for the specific challenges in the oral cavity. Oral tissues express a variety of G-protein-coupled P2Y receptors for ATP and P1 receptors for adenosine in addition to ionotropic P2X receptors for ATP. When these receptors are combined with the plethora of extracellular enzymes capable of manipulating extracellular agonist levels, a complex system for regulating oral health emerges, and recent findings have begun to identify a key role for purinergic signaling in oral pathophysiology. For example, the manipulation of extracellular ATP levels by P. gingivalis reduces inflammasome activation and apoptosis linked to P2X(7) receptor activation. Release of ATP by periodontal ligaments may link mechanical strain to bone remodeling. Activation of P2X receptors is implicated in dental pain, and receptor antagonists represent important targets for new analgesics. Altered levels of adenosine receptors in periodontal disease also suggest a role for nucleosides in dental signaling. The intricacies of the purinergic signaling system make it well-suited for the unique concerns of dental research, and future findings will doubtless confirm this importance.
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Affiliation(s)
- J C Lim
- Department of Anatomy, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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27
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Belikoff BG, Vaickus LJ, Sitkovsky M, Remick DG. A2B adenosine receptor expression by myeloid cells is proinflammatory in murine allergic-airway inflammation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 189:3707-13. [PMID: 22956582 PMCID: PMC3448803 DOI: 10.4049/jimmunol.1201207] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Asthma is a chronic condition with high morbidity and healthcare costs, and cockroach allergens are an established cause of urban pediatric asthma. A better understanding of cell types involved in promoting lung inflammation could provide new targets for the treatment of chronic pulmonary disease. Because of its role in regulating myeloid cell-dependent inflammatory processes, we examined A(2B) R expression by myeloid cells in a cockroach allergen model of murine asthma-like pulmonary inflammation. Both systemic and myeloid tissue-specific A(2B) R deletion significantly decreased pulmonary inflammatory cell recruitment, airway mucin production, and proinflammatory cytokine secretion after final allergen challenge in sensitized mice. A(2B) R deficiency resulted in a dramatic reduction on Th2-type airways responses with decreased pulmonary eosinophilia without augmenting neutrophilia, and decreased lung IL-4, IL-5, and IL-13 production. Chemokine analysis demonstrated that eotaxin 1 and 2 secretion in response to repeated allergen challenge is myeloid cell A(2B) R dependent. In contrast, there were no differences in the levels of the CXC chemokines keratinocyte-derived chemokine and MIP-2 in the myeloid cell A(2B) R-deficient mice, strengthening A(2B) R involvement in the development of Th2-type airways inflammation. Proinflammatory TNF-α, IFN-γ, and IL-17 secretion were also reduced in systemic and myeloid tissue-specific A(2B) R deletion mouse lines. Our results demonstrate Th2-type predominance for A(2B) R expression by myeloid cells as a mechanism of development of asthma-like pulmonary inflammation.
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Affiliation(s)
- Bryan G. Belikoff
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, 02118, USA
| | - Louis J. Vaickus
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, 02118, USA
| | - Michail Sitkovsky
- New England Inflammation and Tissue Protection Institute, Northeastern University, Boston, Massachusetts, 02115, USA
| | - Daniel G. Remick
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, 02118, USA
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Marek GJ. Activation of adenosine₁ receptors induces antidepressant-like, anti-impulsive effects on differential reinforcement of low-rate 72-s behavior in rats. J Pharmacol Exp Ther 2012; 341:564-70. [PMID: 22323824 DOI: 10.1124/jpet.112.191718] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Stress and psychiatric illness have been associated with a dysregulation of glutamatergic neurotransmission. Recently, positive allosteric modulators (PAMs) of the metabotropic glutamate 2 (mGlu₂) receptor have been found to exert antidepressant-like activity in rats performing under a differential reinforcement of low rate (DRL) 72-s schedule. An autoreceptor role at glutamatergic synapses is the most salient physiological role played by the mGlu₂ receptor. Adenosine A₁ receptors play a heteroreceptor role at many of the same forebrain synapses where mGlu₂ autoreceptors are found. Agonists and/or PAMs of mGlu₂ receptors act similarly to adenosine A₁ receptor agonists with respect to a wide range of electrophysiological, biochemical, and behavioral responses mediated by limbic circuitry thought to play a role in the pathophysiology of neuropsychiatric disease and to mediate therapeutic drug effects. Therefore, the role of adenosine A₁ receptor activation on rat DRL 72-s behavior was explored to provide preclinical evidence consistent or inconsistent with potential antidepressant effects. The adenosine A₁ receptor agonist N⁶-cyclohexyladenosine (CHA) increased the reinforcement rate, decreased the response rate, and induced a rightward shift in inter-response time distributions in a dose-dependent fashion similar to most known antidepressant drugs. The adenosine A₁ receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) blocked these antidepressant-like effects. These novel observations with CHA and DPCPX suggest that activation of adenosine A₁ receptors could contribute to antidepressant effects, in addition to previous preclinical reports of anxiolytic and antipsychotic effects. By implication, targeting a dysregulated glutamatergic system may be an important principle in discovering novel antidepressant agents that may also possess anti-impulsive activity.
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Affiliation(s)
- Gerard J Marek
- Abbott Laboratories, Neuroscience Development, GPRD, R48B, Bldg. AP04-1, 100 Abbott Park Road, Abbott Park, IL 60064-6075, USA.
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Fishman P, Bar-Yehuda S, Liang BT, Jacobson KA. Pharmacological and therapeutic effects of A3 adenosine receptor agonists. Drug Discov Today 2011; 17:359-66. [PMID: 22033198 DOI: 10.1016/j.drudis.2011.10.007] [Citation(s) in RCA: 175] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/27/2011] [Accepted: 10/12/2011] [Indexed: 10/16/2022]
Abstract
The A(3) adenosine receptor (A(3)AR) coupled to G(i) (inhibitory regulative guanine nucleotide-binding protein) mediates anti-inflammatory, anticancer and anti-ischemic protective effects. The receptor is overexpressed in inflammatory and cancer cells, while low expression is found in normal cells, rendering the A(3)AR as a potential therapeutic target. Highly selective A(3)AR agonists have been synthesized and molecular recognition in the binding site has been characterized. In this article, we summarize preclinical and clinical human studies that demonstrate that A(3)AR agonists induce specific anti-inflammatory and anticancer effects through a molecular mechanism that entails modulation of the Wnt and the NF-κB signal transduction pathways. At present, A(3)AR agonists are being developed for the treatment of inflammatory diseases, including rheumatoid arthritis (RA) and psoriasis; ophthalmic diseases such as dry eye syndrome and glaucoma; liver diseases such as hepatocellular carcinoma and hepatitis.
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Affiliation(s)
- Pnina Fishman
- Can-Fite BioPharma Ltd, Kiryat-Matalon, 10 Bareket St, PO Box 7537, Petah-Tikva 49170, Israel
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Du L, Gao ZG, Nithipatikom K, Ijzerman AP, Veldhoven JPDV, Jacobson KA, Gross GJ, Auchampach JA. Protection from myocardial ischemia/reperfusion injury by a positive allosteric modulator of the A₃ adenosine receptor. J Pharmacol Exp Ther 2011; 340:210-7. [PMID: 22011434 DOI: 10.1124/jpet.111.187559] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Adenosine is increased in ischemic tissues where it serves a protective role by activating adenosine receptors (ARs), including the A₃ AR subtype. We investigated the effect of N-{2-[(3,4-dichlorophenyl)amino]quinolin-4-yl}cyclohexanecarboxamide (LUF6096), a positive allosteric modulator of the A₃ AR, on infarct size in a barbital-anesthetized dog model of myocardial ischemia/reperfusion injury. Dogs were subjected to 60 min of coronary artery occlusion and 3 h of reperfusion. Infarct size was assessed by macrohistochemical staining. Three experimental groups were included in the study. Groups I and II received two doses of vehicle or LUF6096 (0.5 mg/kg i.v. bolus), one administered before ischemia and the other immediately before reperfusion. Group III received a single dose of LUF6096 (1 mg/kg i.v. bolus) immediately before reperfusion. In preliminary in vitro studies, LUF6096 was found to exert potent enhancing activity (EC₅₀ 114.3 ± 15.9 nM) with the canine A₃ AR in a guanosine 5'-[γ-[³⁵S]thio]triphosphate binding assay. LUF6096 increased the maximal efficacy of the partial A₃ AR agonist 2-chloro-N⁶-(3-iodobenzyl)adenosine-5'-N-methylcarboxamide and the native agonist adenosine more than 2-fold while producing a slight decrease in potency. In the dog studies, administration of LUF6096 had no effect on any hemodynamic parameter measured. Pretreatment with LUF6096 before coronary occlusion and during reperfusion in group II dogs produced a marked reduction in infarct size (∼50% reduction) compared with group I vehicle-treated dogs. An equivalent reduction in infarct size was observed when LUF6096 was administered immediately before reperfusion in group III dogs. This is the first study to demonstrate efficacy of an A₃ AR allosteric enhancer in an in vivo model of infarction.
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Affiliation(s)
- Lili Du
- Department of Pharmacology and the Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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31
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Hua X, Chason KD, Patel JY, Naselsky WC, Tilley SL. IL-4 amplifies the pro-inflammatory effect of adenosine in human mast cells by changing expression levels of adenosine receptors. PLoS One 2011; 6:e24947. [PMID: 21966389 PMCID: PMC3180290 DOI: 10.1371/journal.pone.0024947] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 08/24/2011] [Indexed: 02/02/2023] Open
Abstract
Adenosine inhalation produces immediate bronchoconstriction in asthmatics but not in normal subjects. The bronchospastic effect of adenosine is largely mediated through adenosine-induced mast cell activation, the mechanism of which is poorly understood due to limitations in culturing human primary mast cells. Here, we show that human umbilical cord blood -derived mast cells incubated with the Th2 cytokine IL-4 develop increased sensitivity to adenosine. Potentiation of anti-IgE- induced and calcium ionophore/PMA-induced degranulation was augmented in mast cells cultured with IL-4, and this effect was reduced or abolished by pre-treatment with A2BsiRNA and selective A2B receptor antagonists, respectively. IL-4 incubation resulted in the increased expression of A2B and reduced expression of A2A adenosine receptors on human mast cells. These results suggest that Th2 cytokines in the asthmatic lung may alter adenosine receptor expression on airway mast cells to promote increased responsiveness to adenosine.
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Affiliation(s)
- Xiaoyang Hua
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, and the Center of Environmental Medicine, Asthma and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Otolaryngology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Kelly D. Chason
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, and the Center of Environmental Medicine, Asthma and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Janki Y. Patel
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, and the Center of Environmental Medicine, Asthma and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Warren C. Naselsky
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, and the Center of Environmental Medicine, Asthma and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Stephen L. Tilley
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, and the Center of Environmental Medicine, Asthma and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
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van der Hoeven D, Wan TC, Gizewski ET, Kreckler LM, Maas JE, Van Orman J, Ravid K, Auchampach JA. A role for the low-affinity A2B adenosine receptor in regulating superoxide generation by murine neutrophils. J Pharmacol Exp Ther 2011; 338:1004-12. [PMID: 21693629 DOI: 10.1124/jpet.111.181792] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The formation of adenosine dampens inflammation by inhibiting most cells of the immune system. Among its actions on neutrophils, adenosine suppresses superoxide generation and regulates chemotactic activity. To date, most evidence implicates the G(s) protein-coupled A(2A) adenosine receptor (AR) as the primary AR subtype responsible for mediating the actions of adenosine on neutrophils by stimulating cAMP production. Given that the A(2B)AR is now known to be expressed in neutrophils and that it is a G(s) protein-coupled receptor, we examined in this study whether it signals to suppress neutrophil activities by using 2-[6-amino-3,5-dicyano-4-[4-(cyclopropylmethoxy)phenyl]pyridin-2-ylsulfanyl]acetamide (BAY 60-6583), a new agonist for the human A(2B)AR that was confirmed in preliminary studies to be a potent and highly selective agonist for the murine A(2B)AR. We found that treating mouse neutrophils with low concentrations (10(-9) and 10(-8) M) of BAY 60-6583 inhibited formylated-methionine-leucine-phenylalanine (fMLP)-stimulated superoxide production by either naive neutrophils, tumor necrosis factor-α-primed neutrophils, or neutrophils isolated from mice treated systemically with lipopolysaccharide. This inhibitory action of BAY 60-6583 was confirmed to involve the A(2B)AR in experiments using neutrophils obtained from A(2B)AR gene knockout mice. It is noteworthy that BAY 60-6583 increased fMLP-stimulated superoxide production at higher concentrations (>1 μM), which was attributed to an AR-independent effect. In a standard Boyden chamber migration assay, BAY 60-6583 alone did not stimulate neutrophil chemotaxis or influence chemotaxis in response to fMLP. These results indicate that the A(2B)AR signals to suppress oxidase activity by murine neutrophils, supporting the idea that this low-affinity receptor for adenosine participates along with the A(2A)AR in regulating the proinflammatory actions of neutrophils.
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Affiliation(s)
- Dharini van der Hoeven
- Department of Pharmacology and the Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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Müller CE, Jacobson KA. Recent developments in adenosine receptor ligands and their potential as novel drugs. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1808:1290-308. [PMID: 21185259 PMCID: PMC3437328 DOI: 10.1016/j.bbamem.2010.12.017] [Citation(s) in RCA: 324] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 12/14/2010] [Accepted: 12/15/2010] [Indexed: 01/16/2023]
Abstract
Medicinal chemical approaches have been applied to all four of the adenosine receptor (AR) subtypes (A(1), A(2A), A(2B), and A(3)) to create selective agonists and antagonists for each. The most recent class of selective AR ligands to be reported is the class of A(2B)AR agonists. The availability of these selective ligands has facilitated research on therapeutic applications of modulating the ARs and in some cases has provided clinical candidates. Prodrug approaches have been developed which improve the bioavailability of the drugs, reduce side-effects, and/or may lead to site-selective effects. The A(2A) agonist regadenoson (Lexiscan®), a diagnostic drug for myocardial perfusion imaging, is the first selective AR agonist to be approved. Other selective agonists and antagonists are or were undergoing clinical trials for a broad range of indications, including capadenoson and tecadenoson (A(1) agonists) for atrial fibrillation, or paroxysmal supraventricular tachycardia, respectively, apadenoson and binodenoson (A(2A) agonists) for myocardial perfusion imaging, preladenant (A(2A) antagonist) for the treatment of Parkinson's disease, and CF101 and CF102 (A(3) agonists) for inflammatory diseases and cancer, respectively.
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Gomez G, Zhao W, Schwartz LB. Disparity in FcεRI-induced degranulation of primary human lung and skin mast cells exposed to adenosine. J Clin Immunol 2011; 31:479-87. [PMID: 21437670 DOI: 10.1007/s10875-011-9517-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 03/07/2011] [Indexed: 11/25/2022]
Abstract
Inhaled and intravenously administered adenosine induces mast cell-mediated (histamine-dependent) bronchospasm in asthmatics without causing urticaria. A differential response to adenosine by human lung and skin mast cells is shown: low concentrations potentiate FcεRI-induced degranulation of human lung mast cells but not that of skin mast cells. Human lung mast cells were found to express ∼ 3-fold more A3AR messenger RNA (mRNA) than skin mast cells, suggesting the involvement of the G(i)-linked A3AR. Indeed, the adenosine-induced potentiation was sensitive to inhibition by pertussis toxin and, furthermore, could be induced with an A3AR-specific agonist. This study reveals a previously unrecognized disparity in the response to adenosine by primary human mast cells from lung and skin that might explain why adenosine induces a pulmonary but not dermatologic allergy-like response in vivo. In addition, we identify the A3AR as a potentiating receptor of FcεRI-induced degranulation, thereby implicating it in the in vivo bronchoconstrictive response to adenosine in asthmatics.
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Affiliation(s)
- Gregorio Gomez
- Department of Internal Medicine, Virginia Commonwealth University, Box 980263, Richmond, VA 23298, USA.
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Fredholm BB, IJzerman AP, Jacobson KA, Linden J, Müller CE. International Union of Basic and Clinical Pharmacology. LXXXI. Nomenclature and classification of adenosine receptors--an update. Pharmacol Rev 2011; 63:1-34. [PMID: 21303899 PMCID: PMC3061413 DOI: 10.1124/pr.110.003285] [Citation(s) in RCA: 1002] [Impact Index Per Article: 77.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In the 10 years since our previous International Union of Basic and Clinical Pharmacology report on the nomenclature and classification of adenosine receptors, no developments have led to major changes in the recommendations. However, there have been so many other developments that an update is needed. The fact that the structure of one of the adenosine receptors has recently been solved has already led to new ways of in silico screening of ligands. The evidence that adenosine receptors can form homo- and heteromultimers has accumulated, but the functional significance of such complexes remains unclear. The availability of mice with genetic modification of all the adenosine receptors has led to a clarification of the functional roles of adenosine, and to excellent means to study the specificity of drugs. There are also interesting associations between disease and structural variants in one or more of the adenosine receptors. Several new selective agonists and antagonists have become available. They provide improved possibilities for receptor classification. There are also developments hinting at the usefulness of allosteric modulators. Many drugs targeting adenosine receptors are in clinical trials, but the established therapeutic use is still very limited.
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Affiliation(s)
- Bertil B Fredholm
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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Kim SH, Nam EJ, Kim YK, Ye YM, Park HS. Functional variability of the adenosine A3 receptor (ADORA3) gene polymorphism in aspirin-induced urticaria. Br J Dermatol 2011; 163:977-85. [PMID: 20716228 DOI: 10.1111/j.1365-2133.2010.09983.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND To improve understanding of aspirin hypersensitivity, this study focused on adenosine as a noncyclooxygenase target molecule of aspirin. Adenosine may affect the release of histamine from cutaneous mast cells through a mechanism mediated by the adenosine A3 receptor. OBJECTIVES To investigate the genetic contribution of adenosine A3 receptor gene (ADORA3) polymorphisms in the pathogenesis of aspirin-induced urticaria (AIU) in a case-control association study in a Korean population. METHODS A case-control association study was performed in 385 patients with AIU and 213 normal controls from a Korean population. The functional variability of genetic polymorphisms in the ADORA3 gene was analysed in in vitro studies that included a luciferase reporter assay and an electrophoretic mobility shift assay (EMSA), and ex vivo studies that included real-time polymerase chain reaction for mRNA expression in peripheral blood mononuclear cells and a histamine release assay. RESULTS A significant association of ADORA3 promoter polymorphism at -1050G/T was found with the phenotype of AIU. Patients with AIU showed higher frequency of the haplotype, ht1 (T(-1050) C(-564) ), compared with normal healthy controls. Moreover, ht1 (TC) was found to be a high-transcript haplotype by the luciferase activity assay, and a -564C allele-specific DNA binding protein was found by EMSA. Increased basophil histamine release was noted in subjects who had the high-transcript haplotype, ht1 (TC). CONCLUSION These results suggest that the high-transcript haplotype, ht1 (TC), of the ADORA3 gene may contribute to the development of cutaneous hyper-reactivity to aspirin, leading to the clinical presentation of AIU.
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Affiliation(s)
- S-H Kim
- Department of Allergy and Rheumatology, Ajou University School of Medicine, San-5, Woncheondong, Youngtonggu, Suwon 442-721, Korea
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Federico S, Paoletta S, Cheong SL, Pastorin G, Cacciari B, Stragliotto S, Klotz KN, Siegel J, Gao ZG, Jacobson KA, Moro S, Spalluto G. Synthesis and biological evaluation of a new series of 1,2,4-triazolo[1,5-a]-1,3,5-triazines as human A(2A) adenosine receptor antagonists with improved water solubility. J Med Chem 2011; 54:877-89. [PMID: 21214204 DOI: 10.1021/jm101349u] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The structure-activity relationship (SAR) of 1,2,4-triazolo[1,5-a]-1,3,5-triazine derivatives related to ZM241385 as antagonists of the A(2A) adenosine receptor (AR) was explored through the synthesis of analogues substituted at the 5 position. The A(2A) AR X-ray structure was used to propose a structural basis for the activity and selectivity of the analogues and to direct the synthetic design strategy to provide access to solvent-exposed regions. Thus, we have identified a point of substitution for the attachment of solubilizing groups to enhance both aqueous solubility and physicochemical properties, maintaining potent interactions with the A(2A) AR and, in some cases, receptor subtype selectivity. Among the most potent and selective novel compounds were a long-chain ether-containing amine congener 20 (K(i) 11.5 nM) and its urethane-protected derivative 14 (K(i) 17.8 nM). Compounds 20 and 31 (K(i) 11.5 and 16.9 nM, respectively) were readily water-soluble up to 10 mM. The analogues were docked in the crystallographic structure of the hA(2A) AR and in a homology model of the hA(3) AR, and the per residue electrostatic and hydrophobic contributions to the binding were assessed and stabilizing factors were proposed.
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Affiliation(s)
- Stephanie Federico
- Dipartimento di Scienze Farmaceutiche, Università di Trieste, Piazzale Europa 1, I-34127 Trieste, Italy
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Abstract
Methylxanthines represent a unique class of drugs for the treatment of asthma. The methylxanthine theophylline has demonstrated efficacy in attenuating the three cardinal features of asthma - reversible airflow obstruction, airway hyperresponsiveness, and airway inflammation. At doses achieving relatively high serum levels in which toxic side effects are sometimes observed, direct bronchodilatory effects of theophylline are recognized. At lower serum concentrations, theophylline is a weak bronchodilator but retains its capacity as an immunomodulator, anti-inflammatory, and bronchoprotective drug. Intense investigation into the molecular mechanisms of action of theophylline has identified several different points of action. Phosphodiesterase inhibition and adenosine receptor antagonism have both been implicated in promoting airway smooth muscle relaxation and bronchodilation. Similar mechanisms of action may explain the inhibitory effects of theophylline on immune cells. At lower concentrations that fail to inhibit phosphodiesterase, effects on histone deacetylase activity are believed to contribute to the immunomodulatory actions of theophylline. Since anti-inflammatory and immunomodulatory effects of methylxanthines are realized at lower serum concentrations than are required for bronchodilation, theophylline's predominant role in asthma treatment is as a controller medication for chronic, persistent disease.
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Affiliation(s)
- Stephen L Tilley
- Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA.
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Abstract
The natural plant alkaloids caffeine and theophylline were the first adenosine receptor (AR) antagonists described in the literature. They exhibit micromolar affinities and are non-selective. A large number of derivatives and analogues were subsequently synthesized and evaluated as AR antagonists. Very potent antagonists have thus been developed with selectivity for each of the four AR subtypes.
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Affiliation(s)
- Christa Müller
- PharmaCenter Bonn, Pharmaceutical Sciences Bonn (PSB), University of Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, An der Immenburg 4, D-53121 Bonn, Germany, Phone +49-228-73-2301, Fax +49-228-73-2567
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bldg. 8A, Rm. B1A-19, NIH, NIDDK, LBC, Bethesda, MD 20892, United States of America, Phone +1-301-496-9024, Fax +1-301-480-8422
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Feoktistov I, Biaggioni I. Role of adenosine A(2B) receptors in inflammation. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2011; 61:115-44. [PMID: 21586358 PMCID: PMC3748596 DOI: 10.1016/b978-0-12-385526-8.00005-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recent progress in our understanding of the unique role of A(2B) receptors in the regulation of inflammation, immunity, and tissue repair was considerably facilitated with the introduction of new pharmacological and genetic tools. However, it also led to seemingly conflicting conclusions on the role of A(2B) adenosine receptors in inflammation with some publications indicating proinflammatory effects and others suggesting the opposite. This chapter reviews the functions of A(2B) receptors in various cell types related to inflammation and integrated effects of A(2B) receptor modulation in several animal models of inflammation. It is argued that translation of current findings into novel therapies would require a better understanding of A(2B) receptor functions in diverse types of inflammatory responses in various tissues and at different points of their progression.
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Affiliation(s)
- Igor Feoktistov
- Department of Medicine, Vanderbilt University, Division of Cardiovascular Medicine, Nashville, Tennessee, USA
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Pastorin G, Federico S, Paoletta S, Corradino M, Cateni F, Cacciari B, Klotz KN, Gao ZG, Jacobson KA, Spalluto G, Moro S. Synthesis and pharmacological characterization of a new series of 5,7-disubstituted-[1,2,4]triazolo[1,5-a][1,3,5]triazine derivatives as adenosine receptor antagonists: A preliminary inspection of ligand-receptor recognition process. Bioorg Med Chem 2010; 18:2524-36. [PMID: 20304654 PMCID: PMC3106415 DOI: 10.1016/j.bmc.2010.02.039] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 02/17/2010] [Accepted: 02/21/2010] [Indexed: 10/19/2022]
Abstract
A new series of triazolotriazines variously substituted at the C5 and N7 (5-25) positions was synthesized and fully characterized at the four adenosine receptor (AR) subtypes. In particular, arylacetyl or arylcarbamoyl moieties were introduced at the N7 position, which enhanced affinity at the hA(2B) and hA(3) ARs, respectively, when utilized on the pyrazolo-triazolopyrimidine nucleus as we reported in the past. In general, compounds with a free amino group at the 7 position (5, 6), showed good affinity at the rat (r) A(2A) AR (range 18.3-96.5nM), while the introduction of a phenylcarbamoyl moiety at the N7 position (12, 19, 24) slightly increased the affinity at the hA(3) AR (range 311-633nM) with respect to the unsubstituted derivatives. The binding profiles of the synthesized analogues seemed to correlate with the substitutions at the C5 and N7 positions. At the hA(2B) AR, derivative 5, which contained a free amino group at the 7 position, was the most potent (EC(50) 3.42microM) and could represent a starting point for searching new non-xanthine hA(2B) AR antagonists. Molecular models of the rA(2A) and hA(3) ARs were constructed by homology to the recently reported crystallographic structure of the hA(2A) AR. A preliminary receptor-driven structure-activity relationship (SAR) based on the analysis of antagonist docking has been provided.
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Affiliation(s)
- Giorgia Pastorin
- Department of Pharmacy, National University of Singapore, Block S4, 18 Science Drive 4, Singapore
| | - Stephanie Federico
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Trieste, Piazzale Europa 1, I-34127 Trieste, Italy
| | - Silvia Paoletta
- Molecular Modeling Section (MMS), Dipartimento di Scienze Farmaceutiche, Università di Padova, Via Marzolo 5, I-35131 Padova, Italy
| | - Marta Corradino
- Molecular Modeling Section (MMS), Dipartimento di Scienze Farmaceutiche, Università di Padova, Via Marzolo 5, I-35131 Padova, Italy
| | - Francesca Cateni
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Trieste, Piazzale Europa 1, I-34127 Trieste, Italy
| | - Barbara Cacciari
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Ferrara, Via Fossato di Mortara 17-19, I-44100 Ferrara, Italy
| | - Karl-Norbert Klotz
- Institut für Pharmakologie und Toxikologie, Universität Würzburg, Versbacher Str. 9, D-97078 Würzburg, Germany
| | - Zhan-Guo Gao
- Molecular Recognition Section (MRS), Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kenneth A. Jacobson
- Molecular Recognition Section (MRS), Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Giampiero Spalluto
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Trieste, Piazzale Europa 1, I-34127 Trieste, Italy
| | - Stefano Moro
- Molecular Modeling Section (MMS), Dipartimento di Scienze Farmaceutiche, Università di Padova, Via Marzolo 5, I-35131 Padova, Italy
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Michael S, Warstat C, Michel F, Yan L, Müller CE, Nieber K. Adenosine A(2A) agonist and A(2B) antagonist mediate an inhibition of inflammation-induced contractile disturbance of a rat gastrointestinal preparation. Purinergic Signal 2009; 6:117-24. [PMID: 20020217 DOI: 10.1007/s11302-009-9174-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Accepted: 12/01/2009] [Indexed: 12/22/2022] Open
Abstract
Adenosine can show anti-inflammatory as well as pro-inflammatory activities. The contribution of the specific adenosine receptor subtypes in various cells, tissues and organs is complex. In this study, we examined the effect of the adenosine A(2A) receptor agonist CGS 21680 and the A(2B)R antagonist PSB-1115 on acute inflammation induced experimentally by 2,4,6-trinitrobenzenesulfonic acid (TNBS) on rat ileum/jejunum preparations. Pre-incubation of the ileum/jejunum segments with TNBS for 30 min resulted in a concentration-dependent inhibition of acetylcholine (ACh)-induced contractions. Pharmacological activation of the A(2A)R with CGS 21680 (0.1-10 microM) pre-incubated simultaneously with TNBS (10 mM) prevented concentration-dependently the TNBS-induced inhibition of the ACh contractions. Stimulation of A(2B)R with the selective agonist BAY 60-6583 (10 microM) did neither result in an increase nor in a further decrease of ACh-induced contractions compared to the TNBS-induced inhibition. The simultaneous pre-incubation of the ileum/jejunum segments with TNBS (10 mM) and the selective A(2B)R antagonist PSB-1115 (100 microM) inhibited the contraction-decreasing effect of TNBS. The effects of the A(2A)R agonist and the A(2B)R antagonist were in the same range as the effect induced by 1 microM methotrexate. The combination of the A(2A)R agonist CGS 21680 and the A(2B)R antagonist PSB-1115 at subthreshold concentrations of both agents found a significant amelioration of the TNBS-diminished contractility. Our results demonstrate that the activation of A(2A) receptors or the blockade of the A(2B) receptors can prevent the inflammation-induced disturbance of the ACh-induced contraction in TNBS pre-treated small intestinal preparations. The combination of both may be useful for the treatment of inflammatory bowel diseases.
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Auchampach JA, Gizewski ET, Wan TC, de Castro S, Brown GG, Jacobson KA. Synthesis and pharmacological characterization of [(125)I]MRS5127, a high affinity, selective agonist radioligand for the A3 adenosine receptor. Biochem Pharmacol 2009; 79:967-73. [PMID: 19917269 DOI: 10.1016/j.bcp.2009.11.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 11/05/2009] [Accepted: 11/09/2009] [Indexed: 10/20/2022]
Abstract
A recently reported selective agonist of the human A(3) adenosine receptor (hA(3)AR), MRS5127 (1'R,2'R,3'S,4'R,5'S)-4'-[2-chloro-6-(3-iodobenzylamino)-purine]-2',3'-O-dihydroxy-bicyclo-[3.1.0]hexane, was radioiodinated and characterized pharmacologically. It contains a rigid bicyclic ring system in place of a 5'-truncated ribose moiety, and was selected for radiolabeling due to its nanomolar binding affinity at both human and rat A(3)ARs. The radioiodination of the N(6)-3-iodobenzyl substituent by iododestannylation of a 3-(trimethylstannyl)benzyl precursor was achieved in 73% yield, measured after purification by HPLC. [(125)I]MRS5127 bound to the human A(3)AR expressed in membranes of stably transfected HEK 293 cells. Specific binding was saturable, competitive, and followed a one-site binding model, with a K(d) value of 5.74+/-0.97nM. At a concentration equivalent to its K(d), non-specific binding comprised 27+/-2% of total binding. In kinetic studies, [(125)I]MRS5127 rapidly associated with the hA(3)AR (t(1/2)=0.514+/-0.014min), and the affinity calculated from association and dissociation rate constants was 3.50+/-1.46nM. The pharmacological profile of ligands in competition experiments with [(125)I]MRS5127 was consistent with the known structure-activity-relationship profile of the hA(3)AR. [(125)I]MRS5127 bound with similar high affinity (K(d), nM) to recombinant A(3)ARs from mouse (4.90+/-0.77), rabbit (2.53+/-0.11), and dog (3.35+/-0.54). For all of the species tested, MRS5127 exhibited A(3)AR agonist activity based on negative coupling to cAMP production. Thus, [(125)I]MRS5127 represents a new species-independent agonist radioligand for the A(3)AR. The major advantage of [(125)I]MRS5127 compared with previously used A(3)AR radioligands is its high affinity, low degree of non-specific binding, and improved A(3)AR selectivity.
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Affiliation(s)
- John A Auchampach
- Department of Pharmacology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, United States.
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Abstract
The study of the A(3) adenosine receptor (A(3)AR) represents a rapidly growing and intense area of research in the adenosine field. The present chapter will provide an overview of the expression patterns, molecular pharmacology and functional role of this A(3)AR subtype under pathophysiological conditions. Through studies utilizing selective A(3)AR agonists and antagonists, or A(3)AR knockout mice, it is now clear that this receptor plays a critical role in the modulation of ischemic diseases as well as in inflammatory and autoimmune pathologies. Therefore, the potential therapeutic use of agonists and antagonists will also be described. The discussion will principally address the use of such compounds in the treatment of brain and heart ischemia, asthma, sepsis and glaucoma. The final part concentrates on the molecular basis of A(3)ARs in autoimmune diseases such as rheumatoid arthritis, and includes a description of clinical trials with the selective agonist CF101. Based on this chapter, it is evident that continued research to discover agonists and antagonists for the A(3)AR subtype is warranted.
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Balo MC, Brea J, Caamaño O, Fernández F, García-Mera X, López C, Loza MI, Nieto MI, Rodríguez-Borges JE. Synthesis and pharmacological evaluation of novel 1- and 8-substituted-3-furfuryl xanthines as adenosine receptor antagonists. Bioorg Med Chem 2009; 17:6755-60. [PMID: 19682912 DOI: 10.1016/j.bmc.2009.07.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 07/10/2009] [Accepted: 07/16/2009] [Indexed: 11/30/2022]
Abstract
The synthesis of an important set of 3-furfurylxanthine derivatives is described. Binding affinities were determined for rat A(1) and human A(2A), A(2B) and A(3) receptors. Several of the 3-furfuryl-7-methylxanthine derivatives showed moderate-to-high affinity at human A(2B) receptors, the most active compound (10d) having a K(i) of 7.4 nM for hA(2B) receptors, with selectivities over rA(1) and hA(2A) receptors up to 14-fold and 11-fold, respectively. Affinities for hA(3) receptors were very low for all members of the set.
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Affiliation(s)
- María Carmen Balo
- Departamento de Química Orgánica, Facultade de Farmacia, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Spain
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Zhou Y, Schneider DJ, Blackburn MR. Adenosine signaling and the regulation of chronic lung disease. Pharmacol Ther 2009; 123:105-16. [PMID: 19426761 PMCID: PMC2743314 DOI: 10.1016/j.pharmthera.2009.04.003] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 04/09/2009] [Indexed: 12/20/2022]
Abstract
Chronic lung diseases such as asthma, chronic obstructive pulmonary disease and interstitial lung disease are characterized by inflammation and tissue remodeling processes that compromise pulmonary function. Adenosine is produced in the inflamed and damaged lung where it plays numerous roles in the regulation of inflammation and tissue remodeling. Extracellular adenosine serves as an autocrine and paracrine signaling molecule by engaging cell surface adenosine receptors. Preclinical and cellular studies suggest that adenosine plays an anti-inflammatory role in processes associated with acute lung disease, where activation of the A(2A)R and A(2B)R has promising implications for the treatment of these disorders. In contrast, there is growing evidence that adenosine signaling through the A(1)R, A(2B)R and A(3)R may serve pro-inflammatory and tissue remodeling functions in chronic lung diseases. This review discusses the current progress of research efforts and clinical trials aimed at understanding the complexities of these signaling pathway as they pertain to the development of treatment strategies for chronic lung diseases.
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MESH Headings
- Acute Disease
- Adenosine/metabolism
- Adenosine Deaminase/genetics
- Adenosine Deaminase/physiology
- Animals
- Chronic Disease
- Disease Models, Animal
- Humans
- Lung Diseases, Interstitial/drug therapy
- Lung Diseases, Interstitial/immunology
- Lung Diseases, Interstitial/metabolism
- Lung Diseases, Interstitial/pathology
- Lung Diseases, Obstructive/drug therapy
- Lung Diseases, Obstructive/immunology
- Lung Diseases, Obstructive/metabolism
- Lung Diseases, Obstructive/pathology
- Purinergic P1 Receptor Agonists
- Purinergic P1 Receptor Antagonists
- Receptors, Purinergic P1/metabolism
- Signal Transduction
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Affiliation(s)
- Yang Zhou
- Department of Biochemistry and Molecular Biology, The University of Texas-Houston Medical School, 6431 Fannin St., Houston, Texas, 77030
| | - Daniel J. Schneider
- Department of Biochemistry and Molecular Biology, The University of Texas-Houston Medical School, 6431 Fannin St., Houston, Texas, 77030
| | - Michael R. Blackburn
- Department of Biochemistry and Molecular Biology, The University of Texas-Houston Medical School, 6431 Fannin St., Houston, Texas, 77030
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Streitová D, Weiterová L, Hofer M, Holá J, Horváth V, Kozubík A, Znojil V. Effect of Adenosine on the Growth of Human T-Lymphocyte Leukemia Cell Line MOLT-4. Cancer Invest 2009; 25:419-26. [PMID: 17882653 DOI: 10.1080/07357900701359973] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Adenosine has been observed to suppress the growth of MOLT-4 human leukemia cells in vitro. Changes in the cell cycle, especially increased percentage of cells in S phase, prolonged generation time, and induction of apoptosis at higher adenosine concentrations have been found to be responsible for the growth suppression. Dipyridamole, a drug inhibiting the cellular uptake of adenosine, reversed partially but significantly the adenosine-induced growth suppression. It follows from these results that the action of adenosine on the MOLT-4 cells comprises its cellular uptake and intracellular operation. These findings present new data on anticancer efficacy of adenosine.
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Affiliation(s)
- Denisa Streitová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic.
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48
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Haskó G, Linden J, Cronstein B, Pacher P. Adenosine receptors: therapeutic aspects for inflammatory and immune diseases. Nat Rev Drug Discov 2009; 7:759-70. [PMID: 18758473 DOI: 10.1038/nrd2638] [Citation(s) in RCA: 860] [Impact Index Per Article: 57.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Adenosine is a key endogenous molecule that regulates tissue function by activating four G-protein-coupled adenosine receptors: A1, A2A, A2B and A3. Cells of the immune system express these receptors and are responsive to the modulatory effects of adenosine in an inflammatory environment. Animal models of asthma, ischaemia, arthritis, sepsis, inflammatory bowel disease and wound healing have helped to elucidate the regulatory roles of the various adenosine receptors in dictating the development and progression of disease. This recent heightened awareness of the role of adenosine in the control of immune and inflammatory systems has generated excitement regarding the potential use of adenosine-receptor-based therapies in the treatment of infection, autoimmunity, ischaemia and degenerative diseases.
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Affiliation(s)
- György Haskó
- Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, 185 South Orange Avenue, Newark, New Jersey 07103, USA.
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Auchampach JA, Kreckler LM, Wan TC, Maas JE, van der Hoeven D, Gizewski E, Narayanan J, Maas GE. Characterization of the A2B adenosine receptor from mouse, rabbit, and dog. J Pharmacol Exp Ther 2009; 329:2-13. [PMID: 19141710 DOI: 10.1124/jpet.108.148270] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have cloned and pharmacologically characterized the A(2B) adenosine receptor (AR) from the dog, rabbit, and mouse. The full coding regions of the dog and mouse A(2B)AR were obtained by reverse transcriptase-polymerase chain reaction, and the rabbit A(2B)AR cDNA was obtained by screening a rabbit brain cDNA library. It is noteworthy that an additional clone was isolated by library screening that was identical in sequence to the full-length rabbit A(2B)AR, with the exception of a 27-base pair deletion in the region encoding amino acids 103 to 111 (A(2B)AR(103-111)). This 9 amino acid deletion is located in the second intracellular loop at the only known splice junction of the A(2B)AR and seems to result from the use of an additional 5' donor site found in the rabbit and dog but not in the human, rat, or mouse sequences. [(3)H]3-Isobutyl-8-pyrrolidinoxanthine and 8-[4-[((4-cyano-[2,6-(3)H]-phenyl)carbamoylmethyl)oxy]phenyl]-1,3-di(n-propyl)xanthine ([(3)H]MRS 1754) bound with high affinity to membranes prepared from human embryonic kidney (HEK) 293 cells expressing mouse, rabbit, and dog A(2B)ARs. Competition binding studies performed with a panel of agonist (adenosine and 2-amino-3,5-dicyano-4-phenylpyridine analogs) and antagonist ligands identified similar potency orders for the A(2B)AR orthologs, although most xanthine antagonists displayed lower binding affinity for the dog A(2B)AR compared with A(2B)ARs from rabbit and mouse. No specific binding could be detected with membranes prepared from HEK 293 cells expressing the rabbit A(2B)AR(103-111) variant. Furthermore, the variant failed to stimulate adenylyl cyclase or calcium mobilization. We conclude that significant differences in antagonist pharmacology of the A(2B)AR exist between species and that some species express nonfunctional variants of the A(2B)AR due to "leaky" splicing.
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Affiliation(s)
- John A Auchampach
- Department of Pharmacology and Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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Abstract
Extracellular adenosine is produced in a coordinated manner from cells following cellular challenge or tissue injury. Once produced, it serves as an autocrine- and paracrine-signaling molecule through its interactions with seven-membrane-spanning G-protein-coupled adenosine receptors. These signaling pathways have widespread physiological and pathophysiological functions. Immune cells express adenosine receptors and respond to adenosine or adenosine agonists in diverse manners. Extensive in vitro and in vivo studies have identified potent anti-inflammatory functions for all of the adenosine receptors on many different inflammatory cells and in various inflammatory disease processes. In addition, specific proinflammatory functions have also been ascribed to adenosine receptor activation. The potent effects of adenosine signaling on the regulation of inflammation suggest that targeting specific adenosine receptor activation or inactivation using selective agonists and antagonists could have important therapeutic implications in numerous diseases. This review is designed to summarize the current status of adenosine receptor signaling in various inflammatory cells and in models of inflammation, with an emphasis on the advancement of adenosine-based therapeutics to treat inflammatory disorders.
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Affiliation(s)
- Michael R Blackburn
- Department of Biochemistry and Molecular Biology, The University of Texas-Houston Medical School, Houston, TX 77030, USA.
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