1
|
Zhu C, Lan X, Wei Z, Yu J, Zhang J. Allosteric modulation of G protein-coupled receptors as a novel therapeutic strategy in neuropathic pain. Acta Pharm Sin B 2024; 14:67-86. [PMID: 38239234 PMCID: PMC10792987 DOI: 10.1016/j.apsb.2023.07.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 06/09/2023] [Accepted: 07/12/2023] [Indexed: 01/22/2024] Open
Abstract
Neuropathic pain is a debilitating pathological condition that presents significant therapeutic challenges in clinical practice. Unfortunately, current pharmacological treatments for neuropathic pain lack clinical efficacy and often lead to harmful adverse reactions. As G protein-coupled receptors (GPCRs) are widely distributed throughout the body, including the pain transmission pathway and descending inhibition pathway, the development of novel neuropathic pain treatments based on GPCRs allosteric modulation theory is gaining momentum. Extensive research has shown that allosteric modulators targeting GPCRs on the pain pathway can effectively alleviate symptoms of neuropathic pain while reducing or eliminating adverse effects. This review aims to provide a comprehensive summary of the progress made in GPCRs allosteric modulators in the treatment of neuropathic pain, and discuss the potential benefits and adverse factors of this treatment. We will also concentrate on the development of biased agonists of GPCRs, and based on important examples of biased agonist development in recent years, we will describe universal strategies for designing structure-based biased agonists. It is foreseeable that, with the continuous improvement of GPCRs allosteric modulation and biased agonist theory, effective GPCRs allosteric drugs will eventually be available for the treatment of neuropathic pain with acceptable safety.
Collapse
Affiliation(s)
- Chunhao Zhu
- School of Pharmacy, Ningxia Medical University, Yinchuan 750004, China
- School of Basic Medical Science, Ningxia Medical University, Yinchuan 750004, China
| | - Xiaobing Lan
- School of Pharmacy, Ningxia Medical University, Yinchuan 750004, China
| | - Zhiqiang Wei
- Medicinal Chemistry and Bioinformatics Center, Ocean University of China, Qingdao 266100, China
| | - Jianqiang Yu
- School of Pharmacy, Ningxia Medical University, Yinchuan 750004, China
| | - Jian Zhang
- School of Pharmacy, Ningxia Medical University, Yinchuan 750004, China
- Medicinal Chemistry and Bioinformatics Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210023, China
| |
Collapse
|
2
|
Oliva P, Suresh RR, Pasquini S, Salmaso V, Will EJ, Tosh DK, Gao ZG, Liu N, Gavrilova O, Vincenzi F, Varani K, Jacobson KA. 2-Amino-5-arylethynyl-thiophen-3-yl-(phenyl)methanones as A 1 Adenosine Receptor Positive Allosteric Modulators. ACS Med Chem Lett 2023; 14:1640-1646. [PMID: 38116442 PMCID: PMC10726435 DOI: 10.1021/acsmedchemlett.3c00315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/06/2023] [Indexed: 12/21/2023] Open
Abstract
A1 adenosine receptor (A1AR) agonists have cerebroprotective, cardioprotective, antinociceptive, and other pharmaceutical applications. We explored the structure-activity relationship of 5-arylethynyl aminothiophenes as A1AR positive allosteric modulators (PAMs). The derivatives were compared in binding and functional assays at the human A1AR, indicating that some fluoro-substituted analogues have enhanced PAM activity. We identified substitution of the terminal phenyl ring in 12 (2-F-Ph), 15 (3,4-F2-Ph, MRS7935), and 21 (2-CF3-Ph) as particularly enhancing the PAM activity. 15 was also shown to act as an A1 ago-PAM with EC50 ≈ 2 μM, without activity (30 μM) at other ARs. Molecular modeling indicated that both the 5-arylethynyl and the 4-neopentyl groups are located in a region outside the receptor transmembrane helix bundle that is in contact with the phospholipid bilayer, consistent with the preference for nonpolar substitution of the aryl moiety. Although they are hydrophobic, these PAMs could provide potential drug candidate molecules for engaging protective A1ARs.
Collapse
Affiliation(s)
- Paola Oliva
- Laboratory
of Bioorganic Chemistry and Mouse Metabolism Core, National
Institute of Diabetes and Digestive and Kidney
Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - R. Rama Suresh
- Laboratory
of Bioorganic Chemistry and Mouse Metabolism Core, National
Institute of Diabetes and Digestive and Kidney
Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Silvia Pasquini
- Department
of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via Fossato di Mortara 17-19, 44121 Ferrara, Italy
| | - Veronica Salmaso
- Laboratory
of Bioorganic Chemistry and Mouse Metabolism Core, National
Institute of Diabetes and Digestive and Kidney
Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Edward J. Will
- Laboratory
of Bioorganic Chemistry and Mouse Metabolism Core, National
Institute of Diabetes and Digestive and Kidney
Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Dilip K. Tosh
- Laboratory
of Bioorganic Chemistry and Mouse Metabolism Core, National
Institute of Diabetes and Digestive and Kidney
Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Zhan-Guo Gao
- Laboratory
of Bioorganic Chemistry and Mouse Metabolism Core, National
Institute of Diabetes and Digestive and Kidney
Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Naili Liu
- Laboratory
of Bioorganic Chemistry and Mouse Metabolism Core, National
Institute of Diabetes and Digestive and Kidney
Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Oksana Gavrilova
- Laboratory
of Bioorganic Chemistry and Mouse Metabolism Core, National
Institute of Diabetes and Digestive and Kidney
Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Fabrizio Vincenzi
- Department
of Translational Medicine, University of
Ferrara, Via Fossato
di Mortara 17-19, 44121 Ferrara, Italy
| | - Katia Varani
- Department
of Translational Medicine, University of
Ferrara, Via Fossato
di Mortara 17-19, 44121 Ferrara, Italy
| | - Kenneth A. Jacobson
- Laboratory
of Bioorganic Chemistry and Mouse Metabolism Core, National
Institute of Diabetes and Digestive and Kidney
Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| |
Collapse
|
3
|
Vincenzi F, Pasquini S, Contri C, Cappello M, Nigro M, Travagli A, Merighi S, Gessi S, Borea PA, Varani K. Pharmacology of Adenosine Receptors: Recent Advancements. Biomolecules 2023; 13:1387. [PMID: 37759787 PMCID: PMC10527030 DOI: 10.3390/biom13091387] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/05/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
Adenosine receptors (ARs) are widely acknowledged pharmacological targets yet are still underutilized in clinical practice. Their ubiquitous distribution in almost all cells and tissues of the body makes them, on the one hand, excellent candidates for numerous diseases, and on the other hand, intrinsically challenging to exploit selectively and in a site-specific manner. This review endeavors to comprehensively depict the substantial advancements witnessed in recent years concerning the development of drugs that modulate ARs. Through preclinical and clinical research, it has become evident that the modulation of ARs holds promise for the treatment of numerous diseases, including central nervous system disorders, cardiovascular and metabolic conditions, inflammatory and autoimmune diseases, and cancer. The latest studies discussed herein shed light on novel mechanisms through which ARs exert control over pathophysiological states. They also introduce new ligands and innovative strategies for receptor activation, presenting compelling evidence of efficacy along with the implicated signaling pathways. Collectively, these emerging insights underscore a promising trajectory toward harnessing the therapeutic potential of these multifaceted targets.
Collapse
Affiliation(s)
- Fabrizio Vincenzi
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (C.C.); (M.C.); (M.N.); (A.T.); (S.M.); (S.G.); (K.V.)
| | - Silvia Pasquini
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, 44121 Ferrara, Italy;
| | - Chiara Contri
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (C.C.); (M.C.); (M.N.); (A.T.); (S.M.); (S.G.); (K.V.)
| | - Martina Cappello
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (C.C.); (M.C.); (M.N.); (A.T.); (S.M.); (S.G.); (K.V.)
| | - Manuela Nigro
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (C.C.); (M.C.); (M.N.); (A.T.); (S.M.); (S.G.); (K.V.)
| | - Alessia Travagli
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (C.C.); (M.C.); (M.N.); (A.T.); (S.M.); (S.G.); (K.V.)
| | - Stefania Merighi
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (C.C.); (M.C.); (M.N.); (A.T.); (S.M.); (S.G.); (K.V.)
| | - Stefania Gessi
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (C.C.); (M.C.); (M.N.); (A.T.); (S.M.); (S.G.); (K.V.)
| | | | - Katia Varani
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (C.C.); (M.C.); (M.N.); (A.T.); (S.M.); (S.G.); (K.V.)
| |
Collapse
|
4
|
Haddad M, Cherchi F, Alsalem M, Al-saraireh YM, Madae’en S. Adenosine Receptors as Potential Therapeutic Analgesic Targets. Int J Mol Sci 2023; 24:13160. [PMID: 37685963 PMCID: PMC10487796 DOI: 10.3390/ijms241713160] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 08/18/2023] [Accepted: 08/23/2023] [Indexed: 09/10/2023] Open
Abstract
Pain represents an international burden and a major socio-economic public health problem. New findings, detailed in this review, suggest that adenosine plays a significant role in neuropathic and inflammatory pain, by acting on its metabotropic adenosine receptors (A1AR, A2AAR, A2BAR, A3AR). Adenosine receptor ligands have a practical translational potential based on the favorable efficacy and safety profiles that emerged from clinical research on various agonists and antagonists for different pathologies. The present review collects the latest studies on selected adenosine receptor ligands in different pain models. Here, we also covered the many hypothesized pathways and the role of newly synthesized allosteric adenosine receptor modulators. This review aims to present a summary of recent research on adenosine receptors as prospective therapeutic targets for a range of pain-related disorders.
Collapse
Affiliation(s)
- Mansour Haddad
- Faculty of Pharmacy, Yarmouk University, Irbid 21163, Jordan
| | - Federica Cherchi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, 50139 Florence, Italy;
| | - Mohammad Alsalem
- School of Medicine, The University of Jordan, Amman 11942, Jordan;
| | - Yousef M. Al-saraireh
- Department of Pharmacology, Faculty of Medicine, Mutah University, P.O. Box 7, Al-Karak 61710, Jordan;
| | - Saba Madae’en
- Department of Clinical Pharmacy and Pharmacy Practice, Faculty of Pharmaceutical Sciences, The Hashemite University, Zarqa 13133, Jordan;
| |
Collapse
|
5
|
Hamilton LJ, Pattabiraman M, Zhong HA, Walker M, Vaughn H, Chandra S. Curcumin Stereoisomer, Cis-Trans Curcumin, as a Novel Ligand to A 1 and A 3 Adenosine Receptors. Pharmaceuticals (Basel) 2023; 16:917. [PMID: 37513829 PMCID: PMC10385834 DOI: 10.3390/ph16070917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/05/2023] [Accepted: 06/16/2023] [Indexed: 07/30/2023] Open
Abstract
Adenosine receptors (ARs) are being explored to generate non-opioid pain therapeutics. Vanilloid compounds, curcumin, capsaicin, and vanillin possess antinociceptive properties through their interactions with the transient receptor potential channel family. However, their binding with adenosine receptors has not been well studied. The hypothesis in this study was that a vanilloid compound, cis-trans curcumin (CTCUR), binds to each of the two Gi-linked AR subtypes (A1AR and A3AR). CTCUR was synthesized from curcumin (CUR) using the cavitand-mediated photoisomerization technique. The cell lines transfected with the specific receptor (A1AR or A3AR) were treated with CTCUR or CUR and the binding was analyzed using competitive assays, confocal microscopy, and docking. The binding assays and molecular docking indicated that CTCUR had Ki values of 306 nM (A1AR) and 400 nM (A3AR). These values suggest that CTCUR is selective for Gi-linked ARs (A1AR or A3AR) over Gs-linked ARs (A2AAR or A2BAR), based on our previous published research. In addition, the docking showed that CTCUR binds to the toggle switch domain of ARs. Curcumin (CUR) did not exhibit binding at any of these receptors. In summary, CTCUR and other modifications of CUR can be developed as novel therapeutic ligands for the Gi-linked ARs (A1AR and A3AR) involved with pain and cancer.
Collapse
Affiliation(s)
- Luke J Hamilton
- Department of Biology, University of Nebraska at Kearney, Kearney, NE 68849, USA
| | - Mahesh Pattabiraman
- Department of Chemistry, University of Nebraska at Kearney, Kearney, NE 68849, USA
| | - Haizhen A Zhong
- Department of Chemistry, University of Nebraska at Omaha, Omaha, NE 68182, USA
| | - Michaela Walker
- Department of Biology, University of Nebraska at Kearney, Kearney, NE 68849, USA
| | - Hilary Vaughn
- Department of Biology, University of Nebraska at Kearney, Kearney, NE 68849, USA
| | - Surabhi Chandra
- Department of Biology, University of Nebraska at Kearney, Kearney, NE 68849, USA
| |
Collapse
|
6
|
Fu K, Chen W, Meng M, Zhao H, Yuan H, Wang Y, Ren Y, Yun Y, Guo D. An allosteric modulator of the adenosine A 1 receptor potentiates the antilipolytic effect in rat adipose tissue. Eur J Pharmacol 2023; 951:175777. [PMID: 37182594 DOI: 10.1016/j.ejphar.2023.175777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 05/04/2023] [Accepted: 05/08/2023] [Indexed: 05/16/2023]
Abstract
The adenosine A1 receptor plays important roles in tuning free fatty acid (FFA) levels and represents an attractive target for metabolic disorders. Though remarkable progress has been achieved in the exploitation of effective (orthosteric) A1 receptor agonists in modulating aberrant FFA levels, the effect of A1 receptor allosteric modulation on lipid homeostasis is less investigated. Herein we sought to explore the effect of an allosteric modulator on the action of an A1 receptor orthosteric agonist in regulating the lipolytic process in vitro and in vivo. We examined the binding kinetics of a selective A1 receptor agonist 2-chloro-N6-cyclopentyladenosine (CCPA) in the absence or presence of an allosteric modulator (2-amino-4,5-dimethyl-3-thienyl)-[3-(trifluoromethyl)-phenyl]methanone (PD81,723) on rat adipocyte membranes. We also examined the allosteric effects of PD81,723 on mediating the CCPA-induced inhibition of cAMP accumulation, HSL (hormone-sensitive lipase) phosphorylation and FFA production in in vitro and in vivo models. Our results demonstrated that PD81,723 slowed down the dissociation of CCPA from the A1 receptor, which, consequently, potentiated the antilipolytic action of CCPA through downregulating the cAMP/HSL pathway. Our study exemplified the application of A1 receptor allosteric modulators as an alternative for metabolic disease treatments.
Collapse
Affiliation(s)
- Kequan Fu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, China
| | - Wenbing Chen
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, China
| | - Mingzhu Meng
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, China
| | - Huimin Zhao
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, China
| | - Haoxing Yuan
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, China
| | - Yinan Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, China
| | - Ying Ren
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, China
| | - Yi Yun
- The Affiliated Suqian First People's Hospital of Nanjing Medical University, 120 Suzhi Road, Suqian, 223800, Jiangsu, China.
| | - Dong Guo
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, China.
| |
Collapse
|
7
|
Pasquini S, Contri C, Cappello M, Borea PA, Varani K, Vincenzi F. Update on the recent development of allosteric modulators for adenosine receptors and their therapeutic applications. Front Pharmacol 2022; 13:1030895. [PMID: 36278183 PMCID: PMC9581118 DOI: 10.3389/fphar.2022.1030895] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Adenosine receptors (ARs) have been identified as promising therapeutic targets for countless pathological conditions, spanning from inflammatory diseases to central nervous system disorders, from cancer to metabolic diseases, from cardiovascular pathologies to respiratory diseases, and beyond. This extraordinary therapeutic potential is mainly due to the plurality of pathophysiological actions of adenosine and the ubiquitous expression of its receptors. This is, however, a double-edged sword that makes the clinical development of effective ligands with tolerable side effects difficult. Evidence of this is the low number of AR agonists or antagonists that have reached the market. An alternative approach is to target allosteric sites via allosteric modulators, compounds endowed with several advantages over orthosteric ligands. In addition to the typical advantages of allosteric modulators, those acting on ARs could benefit from the fact that adenosine levels are elevated in pathological tissues, thus potentially having negligible effects on normal tissues where adenosine levels are maintained low. Several A1 and various A3AR allosteric modulators have been identified so far, and some of them have been validated in different preclinical settings, achieving promising results. Less fruitful, instead, has been the discovery of A2A and A2BAR allosteric modulators, although the results obtained up to now are encouraging. Collectively, data in the literature suggests that allosteric modulators of ARs could represent valuable pharmacological tools, potentially able to overcome the limitations of orthosteric ligands.
Collapse
Affiliation(s)
- Silvia Pasquini
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Ferrara, Italy
| | - Chiara Contri
- Department of Translational Medicine, University of Ferrara, Ferrara, Italy
| | - Martina Cappello
- Department of Translational Medicine, University of Ferrara, Ferrara, Italy
| | | | - Katia Varani
- Department of Translational Medicine, University of Ferrara, Ferrara, Italy
- *Correspondence: Katia Varani,
| | - Fabrizio Vincenzi
- Department of Translational Medicine, University of Ferrara, Ferrara, Italy
| |
Collapse
|
8
|
Hao JW, Qiao WL, Li Q, Wei S, Li XM, Liu TT, Qiu CY, Hu WP. A1 Adenosine Receptor Activation Inhibits P2X3 Receptor-Mediated ATP Currents in Rat Dorsal Root Ganglion Neurons. Mol Neurobiol 2022; 59:7025-7035. [PMID: 36074232 DOI: 10.1007/s12035-022-03019-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 08/26/2022] [Indexed: 10/14/2022]
Abstract
Purinergic signaling is involved in multiple pain processes. P2X3 receptor is a key target in pain therapeutics, while A1 adenosine receptor signaling plays a role in analgesia. However, it remains unclear whether there is a link between them in pain. The present results showed that the A1 adenosine receptor agonist N6-cyclopentyladenosine (CPA) concentration dependently suppressed P2X3 receptor-mediated and α,β-methylene-ATP (α,β-meATP)-evoked inward currents in rat dorsal root ganglion (DRG) neurons. CPA significantly decreased the maximal current response to α,β-meATP, as shown a downward shift of the concentration-response curve for α,β-meATP. CPA suppressed ATP currents in a voltage-independent manner. Inhibition of ATP currents by CPA was completely prevented by the A1 adenosine receptor antagonist KW-3902, and disappeared after the intracellular dialysis of either the Gi/o protein inhibitor pertussis toxin, the adenylate cyclase activator forskolin, or the cAMP analog 8-Br-cAMP. Moreover, CPA suppressed the membrane potential depolarization and action potential bursts, which were induced by α,β-meATP in DRG neurons. Finally, CPA relieved α,β-meATP-induced nociceptive behaviors in rats by activating peripheral A1 adenosine receptors. These results indicated that CPA inhibited the activity of P2X3 receptors in rat primary sensory neurons by activating A1 adenosine receptors and its downstream cAMP signaling pathway, revealing a novel peripheral mechanism underlying its analgesic effect.
Collapse
Affiliation(s)
- Jia-Wei Hao
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China.,School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China
| | - Wen-Long Qiao
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China.,School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China
| | - Qing Li
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China.,School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China
| | - Shuang Wei
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China.,School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China
| | - Xue-Mei Li
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China
| | - Ting-Ting Liu
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China
| | - Chun-Yu Qiu
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China
| | - Wang-Ping Hu
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China. .,Hubei College of Chinese Medicine, 87 Xueyuan Road, Jingzhou, 434020, Hubei, People's Republic of China.
| |
Collapse
|
9
|
Mahmood A, Iqbal J. Purinergic receptors modulators: An emerging pharmacological tool for disease management. Med Res Rev 2022; 42:1661-1703. [PMID: 35561109 DOI: 10.1002/med.21888] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/16/2022] [Accepted: 05/04/2022] [Indexed: 11/10/2022]
Abstract
Purinergic signaling is mediated through extracellular nucleotides (adenosine 5'-triphosphate, uridine-5'-triphosphate, adenosine diphosphate, uridine-5'-diphosphate, and adenosine) that serve as signaling molecules. In the early 1990s, purines and pyrimidine receptors were cloned and characterized drawing the attention of scientists toward this aspect of cellular signaling. This signaling pathway is comprised of four subtypes of adenosine receptors (P1), eight subtypes of G-coupled protein receptors (P2YRs), and seven subtypes of ligand-gated ionotropic receptors (P2XRs). In current studies, the pathophysiology and therapeutic potentials of these receptors have been focused on. Various ligands, modulating the functions of purinergic receptors, are in current clinical practices for the treatment of various neurodegenerative disorders and cardiovascular diseases. Moreover, several purinergic receptors ligands are in advanced phases of clinical trials as a remedy for depression, epilepsy, autism, osteoporosis, atherosclerosis, myocardial infarction, diabetes, irritable bowel syndrome, and cancers. In the present study, agonists and antagonists of purinergic receptors have been summarized that may serve as pharmacological tools for drug design and development.
Collapse
Affiliation(s)
- Abid Mahmood
- Centre for Advanced Drug Research, COMSATS University Islamabad, Abbottabad, Pakistan
| | - Jamshed Iqbal
- Centre for Advanced Drug Research, COMSATS University Islamabad, Abbottabad, Pakistan
| |
Collapse
|
10
|
Catarzi D, Varano F, Vigiani E, Calenda S, Melani F, Varani K, Vincenzi F, Pasquini S, Mennini N, Nerli G, Dal Ben D, Volpini R, Colotta V. 4-Heteroaryl Substituted Amino-3,5-Dicyanopyridines as New Adenosine Receptor Ligands: Novel Insights on Structure-Activity Relationships and Perspectives. Pharmaceuticals (Basel) 2022; 15:ph15040478. [PMID: 35455475 PMCID: PMC9024521 DOI: 10.3390/ph15040478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/31/2022] [Accepted: 04/09/2022] [Indexed: 12/04/2022] Open
Abstract
A new set of amino-3,5-dicyanopyridines was synthesized and biologically evaluated at the adenosine receptors (ARs). This chemical class is particularly versatile, as small structural modifications can influence not only affinity and selectivity, but also the pharmacological profile. Thus, in order to deepen the structure–activity relationships (SARs) of this series, different substituents were evaluated at the diverse positions on the dicyanopyridine scaffold. In general, the herein reported compounds show nanomolar binding affinity and interact better with both the human (h) A1 and A2A ARs than with the other subtypes. Docking studies at hAR structure were performed to rationalize the observed affinity data. Of interest are compounds 1 and 5, which can be considered as pan ligands as binding all the ARs with comparable nanomolar binding affinity (A1AR: 1, Ki = 9.63 nM; 5, Ki = 2.50 nM; A2AAR: 1, Ki = 21 nM; 5, Ki = 24 nM; A3AR: 1, Ki = 52 nM; 5, Ki = 25 nM; A2BAR: 1, EC50 = 1.4 nM; 5, EC50 = 1.12 nM). Moreover, these compounds showed a partial agonist profile at all the ARs. This combined AR partial agonist activity could lead us to hypothesize a potential effect in the repair process of damaged tissue that would be beneficial in both wound healing and remodeling.
Collapse
Affiliation(s)
- Daniela Catarzi
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy; (F.V.); (E.V.); (S.C.); (F.M.); (V.C.)
- Correspondence:
| | - Flavia Varano
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy; (F.V.); (E.V.); (S.C.); (F.M.); (V.C.)
| | - Erica Vigiani
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy; (F.V.); (E.V.); (S.C.); (F.M.); (V.C.)
| | - Sara Calenda
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy; (F.V.); (E.V.); (S.C.); (F.M.); (V.C.)
| | - Fabrizio Melani
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy; (F.V.); (E.V.); (S.C.); (F.M.); (V.C.)
| | - Katia Varani
- Dipartimento di Medicina Traslazionale, Università degli Studi di Ferrara, Via Luigi Borsari 46, 44121 Ferrara, Italy; (K.V.); (F.V.); (S.P.)
| | - Fabrizio Vincenzi
- Dipartimento di Medicina Traslazionale, Università degli Studi di Ferrara, Via Luigi Borsari 46, 44121 Ferrara, Italy; (K.V.); (F.V.); (S.P.)
| | - Silvia Pasquini
- Dipartimento di Medicina Traslazionale, Università degli Studi di Ferrara, Via Luigi Borsari 46, 44121 Ferrara, Italy; (K.V.); (F.V.); (S.P.)
| | - Natascia Mennini
- Dipartimento di Chimica Ugo Schiff, Università degli Studi di Firenze, Via della Lastruccia, 3, 50019 Sesto Fiorentino, Italy; (N.M.); (G.N.)
| | - Giulia Nerli
- Dipartimento di Chimica Ugo Schiff, Università degli Studi di Firenze, Via della Lastruccia, 3, 50019 Sesto Fiorentino, Italy; (N.M.); (G.N.)
| | - Diego Dal Ben
- Scuola di Scienze del Farmaco e dei Prodotti della Salute, Università degli Studi di Camerino, Via S.Agostino 1, 62032 Camerino, Italy; (D.D.B.); (R.V.)
| | - Rosaria Volpini
- Scuola di Scienze del Farmaco e dei Prodotti della Salute, Università degli Studi di Camerino, Via S.Agostino 1, 62032 Camerino, Italy; (D.D.B.); (R.V.)
| | - Vittoria Colotta
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy; (F.V.); (E.V.); (S.C.); (F.M.); (V.C.)
| |
Collapse
|
11
|
Adenosine Receptors in Neuropsychiatric Disorders: Fine Regulators of Neurotransmission and Potential Therapeutic Targets. Int J Mol Sci 2022; 23:ijms23031219. [PMID: 35163142 PMCID: PMC8835915 DOI: 10.3390/ijms23031219] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 12/16/2022] Open
Abstract
Adenosine exerts an important role in the modulation of central nervous system (CNS) activity. Through the interaction with four G-protein coupled receptor (GPCR) subtypes, adenosine subtly regulates neurotransmission, interfering with the dopaminergic, glutamatergic, noradrenergic, serotoninergic, and endocannabinoid systems. The inhibitory and facilitating actions of adenosine on neurotransmission are mainly mediated by A1 and A2A adenosine receptors (ARs), respectively. Given their role in the CNS, ARs are promising therapeutic targets for neuropsychiatric disorders where altered neurotransmission represents the most likely etiological hypothesis. Activating or blocking ARs with specific pharmacological agents could therefore restore the balance of altered neurotransmitter systems, providing the rationale for the potential treatment of these highly debilitating conditions. In this review, we summarize and discuss the most relevant studies concerning AR modulation in psychotic and mood disorders such as schizophrenia, bipolar disorders, depression, and anxiety, as well as neurodevelopment disorders such as autism spectrum disorder (ASD), fragile X syndrome (FXS), attention-deficit hyperactivity disorder (ADHD), and neuropsychiatric aspects of neurodegenerative disorders.
Collapse
|
12
|
Lutsenko RV. ON THE QUESTION OF ADENOSINE SYSTEM PARTICIPATION IN THE PATHOGENESIS OF NEUROSES. BULLETIN OF PROBLEMS BIOLOGY AND MEDICINE 2022. [DOI: 10.29254/2077-4214-2022-4-167-76-83] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
13
|
Positive allosteric mechanisms of adenosine A 1 receptor-mediated analgesia. Nature 2021; 597:571-576. [PMID: 34497422 PMCID: PMC8711093 DOI: 10.1038/s41586-021-03897-2] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 08/11/2021] [Indexed: 02/08/2023]
Abstract
The adenosine A1 receptor (A1R) is a promising therapeutic target for non-opioid analgesic agents to treat neuropathic pain1,2. However, development of analgesic orthosteric A1R agonists has failed because of a lack of sufficient on-target selectivity as well as off-tissue adverse effects3. Here we show that [2-amino-4-(3,5-bis(trifluoromethyl)phenyl)thiophen-3-yl)(4-chlorophenyl)methanone] (MIPS521), a positive allosteric modulator of the A1R, exhibits analgesic efficacy in rats in vivo through modulation of the increased levels of endogenous adenosine that occur in the spinal cord of rats with neuropathic pain. We also report the structure of the A1R co-bound to adenosine, MIPS521 and a Gi2 heterotrimer, revealing an extrahelical lipid-detergent-facing allosteric binding pocket that involves transmembrane helixes 1, 6 and 7. Molecular dynamics simulations and ligand kinetic binding experiments support a mechanism whereby MIPS521 stabilizes the adenosine-receptor-G protein complex. This study provides proof of concept for structure-based allosteric drug design of non-opioid analgesic agents that are specific to disease contexts.
Collapse
|
14
|
Metzner K, Gross T, Balzulat A, Wack G, Lu R, Schmidtko A. Lack of efficacy of a partial adenosine A1 receptor agonist in neuropathic pain models in mice. Purinergic Signal 2021; 17:503-514. [PMID: 34313915 PMCID: PMC8410902 DOI: 10.1007/s11302-021-09806-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 06/28/2021] [Indexed: 12/25/2022] Open
Abstract
Previous studies suggest that adenosine A1 receptors (A1R) modulate the processing of pain. The aim of this study was to characterize the distribution of A1R in nociceptive tissues and to evaluate whether targeting A1R with the partial agonist capadenoson may reduce neuropathic pain in mice. The cellular distribution of A1R in dorsal root ganglia (DRG) and the spinal cord was analyzed using fluorescent in situ hybridization. In behavioral experiments, neuropathic pain was induced by spared nerve injury or intraperitoneal injection of paclitaxel, and tactile hypersensitivities were determined using a dynamic plantar aesthesiometer. Whole-cell patch-clamp recordings were performed to assess electrophysiological properties of dissociated DRG neurons. We found A1R to be expressed in populations of DRG neurons and dorsal horn neurons involved in the processing of pain. However, administration of capadenoson at established in vivo doses (0.03–1.0 mg/kg) did not alter mechanical hypersensitivity in the spared nerve injury and paclitaxel models of neuropathic pain, whereas the standard analgesic pregabalin significantly inhibited the pain behavior. Moreover, capadenoson failed to affect potassium currents in DRG neurons, in contrast to a full A1R agonist. Despite expression of A1R in nociceptive neurons, our data do not support the hypothesis that pharmacological intervention with partial A1R agonists might be a valuable approach for the treatment of neuropathic pain.
Collapse
Affiliation(s)
- Katharina Metzner
- Institute of Pharmacology and Clinical Pharmacy, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany.
| | - Tilman Gross
- Institute of Pharmacology and Clinical Pharmacy, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| | - Annika Balzulat
- Institute of Pharmacology and Clinical Pharmacy, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| | - Gesine Wack
- Institute of Pharmacology and Clinical Pharmacy, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| | - Ruirui Lu
- Institute of Pharmacology and Clinical Pharmacy, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| | - Achim Schmidtko
- Institute of Pharmacology and Clinical Pharmacy, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| |
Collapse
|
15
|
Matthee C, Terre'Blanche G, Legoabe LJ, Janse van Rensburg HD. Exploration of chalcones and related heterocycle compounds as ligands of adenosine receptors: therapeutics development. Mol Divers 2021; 26:1779-1821. [PMID: 34176057 DOI: 10.1007/s11030-021-10257-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 06/15/2021] [Indexed: 12/20/2022]
Abstract
Adenosine receptors (ARs) are ubiquitously distributed throughout the mammalian body where they are involved in an extensive list of physiological and pathological processes that scientists have only begun to decipher. Resultantly, AR agonists and antagonists have been the focus of multiple drug design and development programmes within the past few decades. Considered to be a privileged scaffold in medicinal chemistry, the chalcone framework has attracted a substantial amount of interest in this regard. Due to the potential liabilities associated with its structure, however, it has become necessary to explore other potentially promising compounds, such as heterocycles, which have successfully been obtained from chalcone precursors in the past. This review aims to summarise the emerging therapeutic importance of adenosine receptors and their ligands, especially in the central nervous system (CNS), while highlighting chalcone and heterocyclic derivatives as promising AR ligand lead compounds.
Collapse
Affiliation(s)
- Chrisna Matthee
- Pharmaceutical Chemistry, School of Pharmacy, North-West University, Private Bag X6001, Potchefstroom, 2520, North West, South Africa
| | - Gisella Terre'Blanche
- Pharmaceutical Chemistry, School of Pharmacy, North-West University, Private Bag X6001, Potchefstroom, 2520, North West, South Africa.,Centre of Excellence for Pharmaceutical Sciences, School of Pharmacy, North-West University, Private Bag X6001, Potchefstroom, 2520, North West, South Africa
| | - Lesetja J Legoabe
- Centre of Excellence for Pharmaceutical Sciences, School of Pharmacy, North-West University, Private Bag X6001, Potchefstroom, 2520, North West, South Africa
| | - Helena D Janse van Rensburg
- Pharmaceutical Chemistry, School of Pharmacy, North-West University, Private Bag X6001, Potchefstroom, 2520, North West, South Africa.
| |
Collapse
|
16
|
Abstract
Extracellular nucleosides and nucleotides have widespread functions in responding to physiological stress. The "purinome" encompasses 4 G-protein-coupled receptors (GPCRs) for adenosine, 8 GPCRs activated by nucleotides, 7 adenosine 5'-triphosphate-gated P2X ion channels, as well as the associated enzymes and transporters that regulate native agonist levels. Purinergic signaling modulators, such as receptor agonists and antagonists, have potential for treating chronic pain. Adenosine and its analogues potently suppress nociception in preclinical models by activating A1 and/or A3 adenosine receptors (ARs), but safely harnessing this pathway to clinically treat pain has not been achieved. Both A2AAR agonists and antagonists are efficacious in pain models. Highly selective A3AR agonists offer a novel approach to treat chronic pain. We have explored the structure activity relationship of nucleoside derivatives at this subtype using a computational structure-based approach. Novel A3AR agonists for pain control containing a bicyclic ring system (bicyclo [3.1.0] hexane) in place of ribose were designed and screened using an in vivo phenotypic model, which reflected both pharmacokinetic and pharmacodynamic parameters. High specificity (>10,000-fold selective for A3AR) was achieved with the aid of receptor homology models based on related GPCR structures. These A3AR agonists are well tolerated in vivo and highly efficacious in models of chronic neuropathic pain. Furthermore, signaling molecules acting at P2X3, P2X4, P2X7, and P2Y12Rs play critical roles in maladaptive pain neuroplasticity, and their antagonists reduce chronic or inflammatory pain, and, therefore, purine receptor modulation is a promising approach for future pain therapeutics. Structurally novel antagonists for these nucleotide receptors were discovered recently.
Collapse
|
17
|
Selvi I, Argun G, Sonmez C, Bozkurt OF, Basar H. Raised Adenosine and Adenosine Deaminase in Bladder Cancer Require Less Postoperative Analgesia Compared with Benign Prostatic Hyperplasia After Transurethral Resection. Indian J Surg 2021. [DOI: 10.1007/s12262-020-02272-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
|
18
|
Vincenzi F, Pasquini S, Battistello E, Merighi S, Gessi S, Borea PA, Varani K. A 1 Adenosine Receptor Partial Agonists and Allosteric Modulators: Advancing Toward the Clinic? Front Pharmacol 2020; 11:625134. [PMID: 33362567 PMCID: PMC7756085 DOI: 10.3389/fphar.2020.625134] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 11/17/2020] [Indexed: 11/21/2022] Open
Affiliation(s)
- Fabrizio Vincenzi
- Department of Translational Medicine and for Romagna, University of Ferrara, Ferrara, Italy
| | - Silvia Pasquini
- Department of Translational Medicine and for Romagna, University of Ferrara, Ferrara, Italy
| | - Enrica Battistello
- Department of Translational Medicine and for Romagna, University of Ferrara, Ferrara, Italy
| | - Stefania Merighi
- Department of Translational Medicine and for Romagna, University of Ferrara, Ferrara, Italy
| | - Stefania Gessi
- Department of Translational Medicine and for Romagna, University of Ferrara, Ferrara, Italy
| | | | - Katia Varani
- Department of Translational Medicine and for Romagna, University of Ferrara, Ferrara, Italy
| |
Collapse
|
19
|
Shaw S, Uniyal A, Gadepalli A, Tiwari V, Belinskaia DA, Shestakova NN, Venugopala KN, Deb PK, Tiwari V. Adenosine receptor signalling: Probing the potential pathways for the ministration of neuropathic pain. Eur J Pharmacol 2020; 889:173619. [DOI: 10.1016/j.ejphar.2020.173619] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/05/2020] [Accepted: 09/29/2020] [Indexed: 12/27/2022]
|
20
|
Targeting Adenosine Receptors: A Potential Pharmacological Avenue for Acute and Chronic Pain. Int J Mol Sci 2020; 21:ijms21228710. [PMID: 33218074 PMCID: PMC7698931 DOI: 10.3390/ijms21228710] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 11/17/2020] [Indexed: 12/14/2022] Open
Abstract
Adenosine is a purine nucleoside, responsible for the regulation of multiple physiological and pathological cellular and tissue functions by activation of four G protein-coupled receptors (GPCR), namely A1, A2A, A2B, and A3 adenosine receptors (ARs). In recent years, extensive progress has been made to elucidate the role of adenosine in pain regulation. Most of the antinociceptive effects of adenosine are dependent upon A1AR activation located at peripheral, spinal, and supraspinal sites. The role of A2AAR and A2BAR is more controversial since their activation has both pro- and anti-nociceptive effects. A3AR agonists are emerging as promising candidates for neuropathic pain. Although their therapeutic potential has been demonstrated in diverse preclinical studies, no AR ligands have so far reached the market. To date, novel pharmacological approaches such as adenosine regulating agents and allosteric modulators have been proposed to improve efficacy and limit side effects enhancing the effect of endogenous adenosine. This review aims to provide an overview of the therapeutic potential of ligands interacting with ARs and the adenosinergic system for the treatment of acute and chronic pain.
Collapse
|
21
|
Piperazine- and Piperidine-Containing Thiazolo[5,4- d]pyrimidine Derivatives as New Potent and Selective Adenosine A 2A Receptor Inverse Agonists. Pharmaceuticals (Basel) 2020; 13:ph13080161. [PMID: 32722122 PMCID: PMC7465344 DOI: 10.3390/ph13080161] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 12/23/2022] Open
Abstract
The therapeutic use of A2A adenosine receptor (AR) antagonists for the treatment of neurodegenerative disorders, such as Parkinson and Alzheimer diseases, is a very promising approach. Moreover, the potential therapeutic role of A2A AR antagonists to avoid both immunoescaping of tumor cells and tumor development is well documented. Herein, we report on the synthesis and biological evaluation of a new set of piperazine- and piperidine- containing 7-amino-2-(furan-2-yl)thiazolo[5,4-d]pyrimidine derivatives designed as human A2A AR antagonists/inverse agonists. Binding and potency data indicated that a good number of potent and selective hA2A AR inverse agonists were found. Amongst them, the 2-(furan-2-yl)-N5-(2-(4-phenylpiperazin-1-yl)ethyl)thiazolo[5,4-d]pyrimidine-5,7-diamine 11 exhibited the highest A2A AR binding affinity (Ki = 8.62 nM) as well as inverse agonist potency (IC50 = 7.42 nM). In addition, bioinformatics prediction using the web tool SwissADME revealed that 8, 11, and 19 possessed good drug-likeness profiles.
Collapse
|
22
|
The Detrimental Action of Adenosine on Glutamate-Induced Cytotoxicity in PC12 Cells Can Be Shifted towards a Neuroprotective Role through A 1AR Positive Allosteric Modulation. Cells 2020; 9:cells9051242. [PMID: 32443448 PMCID: PMC7290574 DOI: 10.3390/cells9051242] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 12/22/2022] Open
Abstract
Glutamate cytotoxicity is implicated in neuronal death in different neurological disorders including stroke, traumatic brain injury, and neurodegenerative diseases. Adenosine is a nucleoside that plays an important role in modulating neuronal activity and its receptors have been identified as promising therapeutic targets for glutamate cytotoxicity. The purpose of this study is to elucidate the role of adenosine and its receptors on glutamate-induced injury in PC12 cells and to verify the protective effect of the novel A1 adenosine receptor positive allosteric modulator, TRR469. Flow cytometry experiments to detect apoptosis revealed that adenosine has a dual role in glutamate cytotoxicity, with A2A and A2B adenosine receptor (AR) activation exacerbating and A1 AR activation improving glutamate-induced cell injury. The overall effect of endogenous adenosine in PC12 cells resulted in a facilitating action on glutamate cytotoxicity, as demonstrated by the use of adenosine deaminase and selective antagonists. However, enhancing the action of endogenous adenosine on A1ARs by TRR469 completely abrogated glutamate-mediated cell death, caspase 3/7 activation, ROS production, and mitochondrial membrane potential loss. Our results indicate a novel potential therapeutic strategy against glutamate cytotoxicity based on the positive allosteric modulation of A1ARs.
Collapse
|
23
|
Deb PK, Deka S, Borah P, Abed SN, Klotz KN. Medicinal Chemistry and Therapeutic Potential of Agonists, Antagonists and Allosteric Modulators of A1 Adenosine Receptor: Current Status and Perspectives. Curr Pharm Des 2020; 25:2697-2715. [PMID: 31333094 DOI: 10.2174/1381612825666190716100509] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/01/2019] [Indexed: 12/28/2022]
Abstract
Adenosine is a purine nucleoside, responsible for the regulation of a wide range of physiological and pathophysiological conditions by binding with four G-protein-coupled receptors (GPCRs), namely A1, A2A, A2B and A3 adenosine receptors (ARs). In particular, A1 AR is ubiquitously present, mediating a variety of physiological processes throughout the body, thus represents a promising drug target for the management of various pathological conditions. Agonists of A1 AR are found to be useful for the treatment of atrial arrhythmia, angina, type-2 diabetes, glaucoma, neuropathic pain, epilepsy, depression and Huntington's disease, whereas antagonists are being investigated for the treatment of diuresis, congestive heart failure, asthma, COPD, anxiety and dementia. However, treatment with full A1 AR agonists has been associated with numerous challenges like cardiovascular side effects, off-target activation as well as desensitization of A1 AR leading to tachyphylaxis. In this regard, partial agonists of A1 AR have been found to be beneficial in enhancing insulin sensitivity and subsequently reducing blood glucose level, while avoiding severe CVS side effects and tachyphylaxis. Allosteric enhancer of A1 AR is found to be potent for the treatment of neuropathic pain, culminating the side effects related to off-target tissue activation of A1 AR. This review provides an overview of the medicinal chemistry and therapeutic potential of various agonists/partial agonists, antagonists and allosteric modulators of A1 AR, with a particular emphasis on their current status and future perspectives in clinical settings.
Collapse
Affiliation(s)
- Pran Kishore Deb
- Faculty of Pharmacy, Philadelphia University, PO Box - 1, 19392, Amman, Jordan
| | - Satyendra Deka
- Pratiksha Institute of Pharmaceutical Sciences, Chandrapur Road, Panikhaiti, Guwahati-26, Assam, India
| | - Pobitra Borah
- Pratiksha Institute of Pharmaceutical Sciences, Chandrapur Road, Panikhaiti, Guwahati-26, Assam, India
| | - Sara N Abed
- Faculty of Pharmacy, Philadelphia University, PO Box - 1, 19392, Amman, Jordan
| | - Karl-Norbert Klotz
- University of Würzburg, Department of Pharmacology and Toxicology Versbacher Str. 9, D-97078 Würzburg, Germany
| |
Collapse
|
24
|
Bhattarai A, Wang J, Miao Y. Retrospective ensemble docking of allosteric modulators in an adenosine G-protein-coupled receptor. Biochim Biophys Acta Gen Subj 2020; 1864:129615. [PMID: 32298791 DOI: 10.1016/j.bbagen.2020.129615] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 02/26/2020] [Accepted: 04/08/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND Ensemble docking has proven useful in drug discovery and development. It increases the hit rate by incorporating receptor flexibility into molecular docking as demonstrated on important drug targets including G-protein-coupled receptors (GPCRs). Adenosine A1 receptor (A1AR) is a key GPCR that has been targeted for treating cardiac ischemia-reperfusion injuries, neuropathic pain and renal diseases. Development of allosteric modulators, compounds binding to distinct and less conserved GPCR target sites compared with agonists and antagonists, has attracted increasing interest for designing selective drugs of the A1AR. Despite significant advances, more effective approaches are needed to discover potent and selective allosteric modulators of the A1AR. METHODS Ensemble docking that integrates Gaussian accelerated molecular dynamic (GaMD) simulations and molecular docking using Autodock has been implemented for retrospective docking of known positive allosteric modulators (PAMs) in the A1AR. RESULTS Ensemble docking outperforms docking of the receptor cryo-EM structure. The calculated docking enrichment factors (EFs) and the area under the receiver operating characteristic curves (AUC) are significantly increased. CONCLUSIONS Receptor ensembles generated from GaMD simulations are able to increase the success rate of discovering PAMs of A1AR. It is important to account for receptor flexibility through GaMD simulations and flexible docking. GENERAL SIGNIFICANCE Ensemble docking is a promising approach for drug discovery targeting flexible receptors.
Collapse
Affiliation(s)
- Apurba Bhattarai
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047, USA
| | - Jinan Wang
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047, USA
| | - Yinglong Miao
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047, USA.
| |
Collapse
|
25
|
Catarzi D, Varano F, Varani K, Vincenzi F, Pasquini S, Dal Ben D, Volpini R, Colotta V. Amino-3,5-Dicyanopyridines Targeting the Adenosine Receptors Ranging from Pan Ligands to Combined A 1/A 2B Partial Agonists. Pharmaceuticals (Basel) 2019; 12:ph12040159. [PMID: 31652622 PMCID: PMC6958422 DOI: 10.3390/ph12040159] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 12/17/2022] Open
Abstract
The amino-3,5-dicyanopyridine derivatives belong to an intriguing series of adenosine receptor (AR) ligands that has been developed by both academic researchers and industry. Indeed, the studies carried out to date underline the versatility of the dicyanopyridine scaffold to obtain AR ligands with not only a wide range of affinities but also with diverse degrees of efficacies at the different ARs. These observations prompted us to investigate on the structure-activity relationships (SARs) of this series leading to important previously reported results. The present SAR study has helped to confirm the 1H-imidazol-2-yl group at R2 position as an important feature for producing potent AR agonists. Moreover, the nature of the R1 substituent highly affects not only affinity/activity at the hA1 and hA2B ARs but also selectivity versus the other subtypes. Potent hA1 and hA2B AR ligands were developed, and among them, the 2-amino-6-[(1H-imidazol-2-ylmethyl)sulfanyl]-4-[4-(prop-2-en-1-yloxy)phenyl]pyridine-3,5-dicarbonitrile (3) is active in the low nanomolar range at these subtypes and shows a good trend of selectivity versus both the hA2A and hA3 ARs. This combined hA1/hA2B partial agonist activity leads to a synergistic effect on glucose homeostasis and could potentially be beneficial in treating diabetes and related complications.
Collapse
Affiliation(s)
- Daniela Catarzi
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy.
| | - Flavia Varano
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy.
| | - Katia Varani
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università degli Studi di Ferrara, Via Fossato di Mortara 17-19, 44121 Ferrara, Italy.
| | - Fabrizio Vincenzi
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università degli Studi di Ferrara, Via Fossato di Mortara 17-19, 44121 Ferrara, Italy.
| | - Silvia Pasquini
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università degli Studi di Ferrara, Via Fossato di Mortara 17-19, 44121 Ferrara, Italy.
| | - Diego Dal Ben
- Scuola di Scienze del Farmaco e dei Prodotti della Salute, Università degli Studi di Camerino, via S.Agostino 1, 62032 Camerino (MC); Italy.
| | - Rosaria Volpini
- Scuola di Scienze del Farmaco e dei Prodotti della Salute, Università degli Studi di Camerino, via S.Agostino 1, 62032 Camerino (MC); Italy.
| | - Vittoria Colotta
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy.
| |
Collapse
|
26
|
Cooper SL, March J, Sabbatini AR, Hill SJ, Jörg M, Scammells PJ, Woolard J. The effect of two selective A 1 -receptor agonists and the bitopic ligand VCP746 on heart rate and regional vascular conductance in conscious rats. Br J Pharmacol 2019; 177:346-359. [PMID: 31596949 PMCID: PMC6989947 DOI: 10.1111/bph.14870] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 09/05/2019] [Accepted: 09/10/2019] [Indexed: 11/30/2022] Open
Abstract
Background and Purpose Adenosine is a local mediator that regulates physiological and pathological processes via activation of four GPCRs (A1, A2A, A2B, and A3). We have investigated the effect of two A1‐receptor‐selective agonists and the novel A1‐receptor bitopic ligand VCP746 on the rat cardiovascular system. Experimental Approach The regional haemodynamic responses of these agonist was investigated in conscious rats. Male Sprague–Dawley rats (350–450 g) were chronically implanted with pulsed Doppler flow probes on the renal, mesenteric arteries and the descending abdominal aorta and the jugular vein and caudal artery catheterized. Cardiovascular responses were measured following intravenous infusion (3 min each dose) of CCPA (120, 400, and 1,200 ng·kg−1·min−1), capadenoson or adenosine (30, 100, and 300 μg·kg−1·min−1), or VCP746 (6, 20, and 60 μg·kg−1·min−1) following pre‐dosing with DPCPX (0.1 mg·kg−1, i.v.) or vehicle. Key Results CCPA produced a significant A1‐receptor‐mediated decrease in heart rate that was accompanied by vasoconstrictions in the renal and mesenteric vascular beds but an increase in hindquarters vascular conductance. The partial agonist capadenoson also produced an A1‐receptor‐mediated bradycardia. In contrast, VCP746 produced increases in heart rate and renal and mesenteric vascular conductance that were not mediated by A1‐receptors. In vitro studies confirmed that VCP746 had potent agonist activity at both A2A‐ and A2B‐receptors. Conclusions and Implications These results suggest VCP746 mediates its cardiovascular effects via activation of A2 rather than A1 adenosine receptors. This has implications for the design of future bitopic ligands that incorporate A1 allosteric ligand moieties.
Collapse
Affiliation(s)
- Samantha L Cooper
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
| | - Julie March
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
| | - Andrea R Sabbatini
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
| | - Stephen J Hill
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
| | - Manuela Jörg
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Peter J Scammells
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Jeanette Woolard
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
| |
Collapse
|
27
|
Betti M, Catarzi D, Varano F, Falsini M, Varani K, Vincenzi F, Pasquini S, di Cesare Mannelli L, Ghelardini C, Lucarini E, Dal Ben D, Spinaci A, Bartolucci G, Menicatti M, Colotta V. Modifications on the Amino-3,5-dicyanopyridine Core To Obtain Multifaceted Adenosine Receptor Ligands with Antineuropathic Activity. J Med Chem 2019; 62:6894-6912. [PMID: 31306001 DOI: 10.1021/acs.jmedchem.9b00106] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A new series of amino-3,5-dicyanopyridines (1-31) was synthesized and biologically evaluated in order to further investigate the potential of this scaffold to obtain adenosine receptor (AR) ligands. In general, the modifications performed have led to compounds having high to good human (h) A1AR affinity and an inverse agonist profile. While most of the compounds are hA1AR-selective, some derivatives behave as mixed hA1AR inverse agonists/A2A and A2B AR antagonists. The latter compounds (9-12) showed that they reduce oxaliplatin-induced neuropathic pain by a mechanism involving the alpha7 subtype of nAchRs, similar to the nonselective AR antagonist caffeine, taken as the reference compound. Along with the pharmacological evaluation, chemical stability of methyl 3-(((6-amino-3,5-dicyano-4-(furan-2-yl)pyridin-2-yl)sulfanyl)methyl)benzoate 10 was assessed in plasma matrices (rat and human), and molecular modeling studies were carried out to better rationalize the available structure-activity relationships.
Collapse
Affiliation(s)
- Marco Betti
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica , Università degli Studi di Firenze , Via Ugo Schiff, 6 , 50019 Sesto Fiorentino , Italy
| | - Daniela Catarzi
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica , Università degli Studi di Firenze , Via Ugo Schiff, 6 , 50019 Sesto Fiorentino , Italy
| | - Flavia Varano
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica , Università degli Studi di Firenze , Via Ugo Schiff, 6 , 50019 Sesto Fiorentino , Italy
| | - Matteo Falsini
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica , Università degli Studi di Firenze , Via Ugo Schiff, 6 , 50019 Sesto Fiorentino , Italy
| | - Katia Varani
- Dipartimento di Scienze Mediche, Sezione di Farmacologia , Università degli Studi di Ferrara , Via Fossato di Mortara 17-19 , 44121 Ferrara , Italy
| | - Fabrizio Vincenzi
- Dipartimento di Scienze Mediche, Sezione di Farmacologia , Università degli Studi di Ferrara , Via Fossato di Mortara 17-19 , 44121 Ferrara , Italy
| | - Silvia Pasquini
- Dipartimento di Scienze Mediche, Sezione di Farmacologia , Università degli Studi di Ferrara , Via Fossato di Mortara 17-19 , 44121 Ferrara , Italy
| | - Lorenzo di Cesare Mannelli
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmacologia e Tossicologia , Università degli Studi di Firenze , Viale Pieraccini, 6 , 50139 Firenze , Italy
| | - Carla Ghelardini
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmacologia e Tossicologia , Università degli Studi di Firenze , Viale Pieraccini, 6 , 50139 Firenze , Italy
| | - Elena Lucarini
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmacologia e Tossicologia , Università degli Studi di Firenze , Viale Pieraccini, 6 , 50139 Firenze , Italy
| | - Diego Dal Ben
- Scuola di Scienze del Farmaco e dei Prodotti della Salute , Università degli Studi di Camerino , Via S. Agostino 1 , 62032 Camerino , Macerata , Italy
| | - Andrea Spinaci
- Scuola di Scienze del Farmaco e dei Prodotti della Salute , Università degli Studi di Camerino , Via S. Agostino 1 , 62032 Camerino , Macerata , Italy
| | - Gianluca Bartolucci
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica , Università degli Studi di Firenze , Via Ugo Schiff, 6 , 50019 Sesto Fiorentino , Italy
| | - Marta Menicatti
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica , Università degli Studi di Firenze , Via Ugo Schiff, 6 , 50019 Sesto Fiorentino , Italy
| | - Vittoria Colotta
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica , Università degli Studi di Firenze , Via Ugo Schiff, 6 , 50019 Sesto Fiorentino , Italy
| |
Collapse
|
28
|
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: 128] [Impact Index Per Article: 25.6] [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.
Collapse
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
| |
Collapse
|
29
|
Cooper SL, Soave M, Jörg M, Scammells PJ, Woolard J, Hill SJ. Probe dependence of allosteric enhancers on the binding affinity of adenosine A 1 -receptor agonists at rat and human A 1 -receptors measured using NanoBRET. Br J Pharmacol 2019; 176:864-878. [PMID: 30644086 PMCID: PMC6433648 DOI: 10.1111/bph.14575] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 11/02/2018] [Accepted: 12/04/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND AND PURPOSE Adenosine is a local mediator that regulates a number of physiological and pathological processes via activation of adenosine A1 -receptors. The activity of adenosine can be regulated at the level of its target receptor via drugs that bind to an allosteric site on the A1 -receptor. Here, we have investigated the species and probe dependence of two allosteric modulators on the binding characteristics of fluorescent and nonfluorescent A1 -receptor agonists. EXPERIMENTAL APPROACH A Nano-luciferase (Nluc) BRET (NanoBRET) methodology was used. This used N-terminal Nluc-tagged A1 -receptors expressed in HEK293T cells in conjunction with both fluorescent A1 -receptor agonists (adenosine and NECA analogues) and a fluorescent antagonist CA200645. KEY RESULTS PD 81,723 and VCP171 elicited positive allosteric effects on the binding affinity of orthosteric agonists at both the rat and human A1 -receptors that showed clear probe dependence. Thus, the allosteric effect on the highly selective partial agonist capadenoson was much less marked than for the full agonists NECA, adenosine, and CCPA in both species. VCP171 and, to a lesser extent, PD 81,723, also increased the specific binding of three fluorescent A1 -receptor agonists in a species-dependent manner that involved increases in Bmax and pKD . CONCLUSIONS AND IMPLICATIONS These results demonstrate the power of the NanoBRET ligand-binding approach to study the effect of allosteric ligands on the binding of fluorescent agonists to the adenosine A1 -receptor in intact living cells. Furthermore, our studies suggest that VCP171 and PD 81,723 may switch a proportion of A1 -receptors to an active agonist conformation (R*).
Collapse
Affiliation(s)
- Samantha L Cooper
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
| | - Mark Soave
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
| | - Manuela Jörg
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Peter J Scammells
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Jeanette Woolard
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
| | - Stephen J Hill
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK
| |
Collapse
|
30
|
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.
Collapse
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
| |
Collapse
|
31
|
Borea PA, Gessi S, Merighi S, Vincenzi F, Varani K. Pharmacology of Adenosine Receptors: The State of the Art. Physiol Rev 2018; 98:1591-1625. [PMID: 29848236 DOI: 10.1152/physrev.00049.2017] [Citation(s) in RCA: 450] [Impact Index Per Article: 75.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Adenosine is a ubiquitous endogenous autacoid whose effects are triggered through the enrollment of four G protein-coupled receptors: A1, A2A, A2B, and A3. Due to the rapid generation of adenosine from cellular metabolism, and the widespread distribution of its receptor subtypes in almost all organs and tissues, this nucleoside induces a multitude of physiopathological effects, regulating central nervous, cardiovascular, peripheral, and immune systems. It is becoming clear that the expression patterns of adenosine receptors vary among cell types, lending weight to the idea that they may be both markers of pathologies and useful targets for novel drugs. This review offers an overview of current knowledge on adenosine receptors, including their characteristic structural features, molecular interactions and cellular functions, as well as their essential roles in pain, cancer, and neurodegenerative, inflammatory, and autoimmune diseases. Finally, we highlight the latest findings on molecules capable of targeting adenosine receptors and report which stage of drug development they have reached.
Collapse
Affiliation(s)
- Pier Andrea Borea
- Department of Medical Sciences, University of Ferrara , Ferrara , Italy
| | - Stefania Gessi
- Department of Medical Sciences, University of Ferrara , Ferrara , Italy
| | - Stefania Merighi
- Department of Medical Sciences, University of Ferrara , Ferrara , Italy
| | - Fabrizio Vincenzi
- Department of Medical Sciences, University of Ferrara , Ferrara , Italy
| | - Katia Varani
- Department of Medical Sciences, University of Ferrara , Ferrara , Italy
| |
Collapse
|
32
|
Identification of novel thiazolo[5,4-d]pyrimidine derivatives as human A1 and A2A adenosine receptor antagonists/inverse agonists. Bioorg Med Chem 2018; 26:3688-3695. [DOI: 10.1016/j.bmc.2018.05.048] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 12/31/2022]
|
33
|
Betti M, Catarzi D, Varano F, Falsini M, Varani K, Vincenzi F, Dal Ben D, Lambertucci C, Colotta V. The aminopyridine-3,5-dicarbonitrile core for the design of new non-nucleoside-like agonists of the human adenosine A 2B receptor. Eur J Med Chem 2018. [PMID: 29525433 DOI: 10.1016/j.ejmech.2018.02.081] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A new series of amino-3,5-dicyanopyridines (3-28) as analogues of the adenosine hA2B receptor agonist BAY60-6583 (compound 1) was synthesized. All the compounds that interact with the hA2B adenosine receptor display EC50 values in the range 9-350 nM behaving as partial agonists, with the only exception being the 2-{[4-(4-acetamidophenyl)-6-amino-3,5-dicyanopyridin-2-yl]thio}acetamide (8) which shows a full agonist profile. Moreover, the 2-[(1H-imidazol-2-yl)methylthio)]-6-amino-4-(4-cyclopropylmethoxy-phenyl)pyridine-3,5-dicarbonitrile (15) turns out to be 3-fold more active than 1 although less selective. This result can be considered a real breakthrough due to the currently limited number of non-adenosine hA2B AR agonists reported in literature. To simulate the binding mode of nucleoside and non-nucleoside agonists at the hA2B AR, molecular docking studies were performed at homology models of this AR subtype developed by using two crystal structures of agonist-bound A2A AR as templates. These investigations allowed us to represent a hypothetical binding mode of hA2B receptor agonists belonging to the amino-3,5-dicyanopyridine series and to rationalize the observed SAR.
Collapse
Affiliation(s)
- Marco Betti
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy
| | - Daniela Catarzi
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy.
| | - Flavia Varano
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy
| | - Matteo Falsini
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy
| | - Katia Varani
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università degli Studi di Ferrara, Via Fossato di Mortara 17-19, 44121 Ferrara, Italy
| | - Fabrizio Vincenzi
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università degli Studi di Ferrara, Via Fossato di Mortara 17-19, 44121 Ferrara, Italy
| | - Diego Dal Ben
- Scuola di Scienze del Farmaco e dei Prodotti della Salute, Università degli Studi di Camerino, Via S. Agostino 1, 62032 Camerino, MC, Italy
| | - Catia Lambertucci
- Scuola di Scienze del Farmaco e dei Prodotti della Salute, Università degli Studi di Camerino, Via S. Agostino 1, 62032 Camerino, MC, Italy
| | - Vittoria Colotta
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy
| |
Collapse
|
34
|
Varani K, Vincenzi F, Merighi S, Gessi S, Borea PA. Biochemical and Pharmacological Role of A1 Adenosine Receptors and Their Modulation as Novel Therapeutic Strategy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1051:193-232. [DOI: 10.1007/5584_2017_61] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
35
|
|
36
|
Adenosine receptor targets for pain. Neuroscience 2016; 338:1-18. [DOI: 10.1016/j.neuroscience.2015.10.031] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 09/29/2015] [Accepted: 10/15/2015] [Indexed: 12/21/2022]
|
37
|
Vincenzi F, Ravani A, Pasquini S, Merighi S, Gessi S, Romagnoli R, Baraldi PG, Borea PA, Varani K. Positive allosteric modulation of A1 adenosine receptors as a novel and promising therapeutic strategy for anxiety. Neuropharmacology 2016; 111:283-292. [DOI: 10.1016/j.neuropharm.2016.09.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 09/05/2016] [Accepted: 09/13/2016] [Indexed: 11/16/2022]
|
38
|
Varano F, Catarzi D, Vincenzi F, Betti M, Falsini M, Ravani A, Borea PA, Colotta V, Varani K. Design, Synthesis, and Pharmacological Characterization of 2-(2-Furanyl)thiazolo[5,4-d]pyrimidine-5,7-diamine Derivatives: New Highly Potent A 2A Adenosine Receptor Inverse Agonists with Antinociceptive Activity. J Med Chem 2016; 59:10564-10576. [PMID: 27933962 DOI: 10.1021/acs.jmedchem.6b01068] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
In this study, we describe the design and synthesis of new N5-substituted-2-(2-furanyl) thiazolo[5,4-d]pyrimidine-5,7-diamines (2-18) and their pharmacological characterization as A2A adenosine receptor (AR) antagonists by using in vitro and in vivo assays. In competition binding experiments two derivatives (13 and 14) emerged as outstanding ligands showing two different affinity values (KH and KL) for the hA2A receptor with the high affinity KH value in the femtomolar range. The in vitro functional activity assays, performed by using cyclic AMP experiments, assessed that they behave as potent inverse agonists at the hA2A AR. Compounds 13 and 14 were evaluated for their antinociceptive activity in acute experimental models of pain showing an effect equal to or greater than that of morphine. Overall, these novel inverse agonists might represent potential drug candidates for an alternative approach to the management of pain.
Collapse
Affiliation(s)
- Flavia Varano
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze , via Ugo Schiff, 6, 50019, Sesto Fiorentino, Italy
| | - Daniela Catarzi
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze , via Ugo Schiff, 6, 50019, Sesto Fiorentino, Italy
| | - Fabrizio Vincenzi
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università degli Studi di Ferrara , via Fossato di Mortara 17-19, 44121, Ferrara, Italy
| | - Marco Betti
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze , via Ugo Schiff, 6, 50019, Sesto Fiorentino, Italy
| | - Matteo Falsini
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze , via Ugo Schiff, 6, 50019, Sesto Fiorentino, Italy
| | - Annalisa Ravani
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università degli Studi di Ferrara , via Fossato di Mortara 17-19, 44121, Ferrara, Italy
| | - Pier Andrea Borea
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università degli Studi di Ferrara , via Fossato di Mortara 17-19, 44121, Ferrara, Italy
| | - Vittoria Colotta
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze , via Ugo Schiff, 6, 50019, Sesto Fiorentino, Italy
| | - Katia Varani
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università degli Studi di Ferrara , via Fossato di Mortara 17-19, 44121, Ferrara, Italy
| |
Collapse
|
39
|
Poli D, Falsini M, Varano F, Betti M, Varani K, Vincenzi F, Pugliese AM, Pedata F, Dal Ben D, Thomas A, Palchetti I, Bettazzi F, Catarzi D, Colotta V. Imidazo[1,2-a]pyrazin-8-amine core for the design of new adenosine receptor antagonists: Structural exploration to target the A 3 and A 2A subtypes. Eur J Med Chem 2016; 125:611-628. [PMID: 27721147 DOI: 10.1016/j.ejmech.2016.09.076] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/23/2016] [Accepted: 09/24/2016] [Indexed: 12/26/2022]
Abstract
The imidazo[1,2-a]pyrazine ring system has been chosen as a new decorable core skeleton for the design of novel adenosine receptor (AR) antagonists targeting either the human (h) A3 or the hA2A receptor subtype. The N8-(hetero)arylcarboxyamido substituted compounds 4-14 and 21-30, bearing a 6-phenyl moiety or not, respectively, show good hA3 receptor affinity and selectivity versus the other ARs. In contrast, the 8-amino-6-(hetero)aryl substituted derivatives designed for targeting the hA2A receptor subtype (compounds 31-38) and also the 6-phenyl analogues 18-20 do not bind the hA2A AR, or show hA1 or balanced hA1/hA2A AR affinity in the micromolar range. Molecular docking of the new hA3 antagonists was carried out to depict their hypothetical binding mode to our refined model of the hA3 receptor. Some derivatives were evaluated for their fluorescent potentiality and showed some fluorescent emission properties. One of the most active hA3 antagonists herein reported, i.e. the 2,6-diphenyl-8-(3-pyridoylamino)imidazo[1,2-a]pyrazine 29, tested in a rat model of cerebral ischemia, delayed the occurrence of anoxic depolarization caused by oxygen and glucose deprivation in the hippocampus and allowed disrupted synaptic activity to recover.
Collapse
Affiliation(s)
- Daniela Poli
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sez. Farmaceutica e Nutraceutica, Universita' degli Studi di Firenze, Via Ugo Schiff 6, 50019, Sesto Fiorentino (FI), Italy
| | - Matteo Falsini
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sez. Farmaceutica e Nutraceutica, Universita' degli Studi di Firenze, Via Ugo Schiff 6, 50019, Sesto Fiorentino (FI), Italy
| | - Flavia Varano
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sez. Farmaceutica e Nutraceutica, Universita' degli Studi di Firenze, Via Ugo Schiff 6, 50019, Sesto Fiorentino (FI), Italy
| | - Marco Betti
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sez. Farmaceutica e Nutraceutica, Universita' degli Studi di Firenze, Via Ugo Schiff 6, 50019, Sesto Fiorentino (FI), Italy
| | - Katia Varani
- Dipartimento di Scienze Mediche, Sez. Farmacologia, Università degli Studi di Ferrara, Via Fossato di Mortara, 17-19, 4412 Ferrara, Italy
| | - Fabrizio Vincenzi
- Dipartimento di Scienze Mediche, Sez. Farmacologia, Università degli Studi di Ferrara, Via Fossato di Mortara, 17-19, 4412 Ferrara, Italy
| | - Anna Maria Pugliese
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sez. Farmacologia e Tossicologia, Università degli Studi di Firenze, Viale Pieraccini, 6, 50139 Firenze, Italy
| | - Felicita Pedata
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sez. Farmacologia e Tossicologia, Università degli Studi di Firenze, Viale Pieraccini, 6, 50139 Firenze, Italy
| | - Diego Dal Ben
- Scuola di Scienze del Farmaco e dei Prodotti della Salute, Università degli Studi di Camerino, Via S. Agostino 1, 62032 Camerino (MC), Italy
| | - Ajiroghene Thomas
- Scuola di Scienze del Farmaco e dei Prodotti della Salute, Università degli Studi di Camerino, Via S. Agostino 1, 62032 Camerino (MC), Italy
| | - Ilaria Palchetti
- Dipartimento di Chimica "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3-13, 50019, Sesto Fiorentino (FI), Italy; Istituto di Biochimica delle Proteine-CNR, Via P.Castellino 111, 80131 Napoli, Italy
| | - Francesca Bettazzi
- Dipartimento di Chimica "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3-13, 50019, Sesto Fiorentino (FI), Italy
| | - Daniela Catarzi
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sez. Farmaceutica e Nutraceutica, Universita' degli Studi di Firenze, Via Ugo Schiff 6, 50019, Sesto Fiorentino (FI), Italy.
| | - Vittoria Colotta
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Sez. Farmaceutica e Nutraceutica, Universita' degli Studi di Firenze, Via Ugo Schiff 6, 50019, Sesto Fiorentino (FI), Italy
| |
Collapse
|
40
|
Janes K, Symons-Liguori AM, Jacobson KA, Salvemini D. Identification of A3 adenosine receptor agonists as novel non-narcotic analgesics. Br J Pharmacol 2016; 173:1253-67. [PMID: 26804983 DOI: 10.1111/bph.13446] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 11/09/2015] [Accepted: 11/22/2015] [Indexed: 12/26/2022] Open
Abstract
Chronic pain negatively impacts the quality of life in a variety of patient populations. The current therapeutic repertoire is inadequate in managing patient pain and warrants the development of new therapeutics. Adenosine and its four cognate receptors (A1 , A2A , A2B and A3 ) have important roles in physiological and pathophysiological states, including chronic pain. Preclinical and clinical studies have revealed that while adenosine and agonists of the A1 and A2A receptors have antinociceptive properties, their therapeutic utility is limited by adverse cardiovascular side effects. In contrast, our understanding of the A3 receptor is only in its infancy, but exciting preclinical observations of A3 receptor antinociception, which have been bolstered by clinical trials of A3 receptor agonists in other disease states, suggest pain relief without cardiovascular side effects and with sufficient tolerability. Our goal herein is to briefly discuss adenosine and its receptors in the context of pathological pain and to consider the current data regarding A3 receptor-mediated antinociception. We will highlight recent findings regarding the impact of the A3 receptor on pain pathways and examine the current state of selective A3 receptor agonists used for these studies. The adenosine-to-A3 receptor pathway represents an important endogenous system that can be targeted to provide safe, effective pain relief from chronic pain.
Collapse
Affiliation(s)
- K Janes
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO, USA
| | - A M Symons-Liguori
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO, USA
| | - K A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - D Salvemini
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO, USA
| |
Collapse
|
41
|
Borea PA, Gessi S, Merighi S, Varani K. Adenosine as a Multi-Signalling Guardian Angel in Human Diseases: When, Where and How Does it Exert its Protective Effects? Trends Pharmacol Sci 2016; 37:419-434. [PMID: 26944097 DOI: 10.1016/j.tips.2016.02.006] [Citation(s) in RCA: 203] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 02/08/2016] [Accepted: 02/09/2016] [Indexed: 12/20/2022]
Abstract
The importance of adenosine for human health cannot be overstated. Indeed, this ubiquitous nucleoside is an integral component of ATP, and regulates the function of every tissue and organ in the body. Acting via receptor-dependent and -independent mechanisms [the former mediated via four G-protein-coupled receptors (GPCRs), A1, A2A, A2B, and A3,], it has a significant role in protecting against cell damage in areas of increased tissue metabolism, and combating organ dysfunction in numerous pathological states. Accordingly, raised levels of adenosine have been demonstrated in epilepsy, ischaemia, pain, inflammation, and cancer, in which its behaviour can be likened to that of a guardian angel, even though there are instances in which overproduction of adenosine is pathological. In this review, we condense the current body of knowledge on the issue, highlighting when, where, and how adenosine exerts its protective effects in both the brain and the periphery.
Collapse
Affiliation(s)
- Pier Andrea Borea
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, Via Fossato di Mortara, 17-19, 44121 Ferrara, Italy.
| | - Stefania Gessi
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, Via Fossato di Mortara, 17-19, 44121 Ferrara, Italy.
| | - Stefania Merighi
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, Via Fossato di Mortara, 17-19, 44121 Ferrara, Italy.
| | - Katia Varani
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, Via Fossato di Mortara, 17-19, 44121 Ferrara, Italy
| |
Collapse
|
42
|
Zulli A, Smith RM, Kubatka P, Novak J, Uehara Y, Loftus H, Qaradakhi T, Pohanka M, Kobyliak N, Zagatina A, Klimas J, Hayes A, La Rocca G, Soucek M, Kruzliak P. Caffeine and cardiovascular diseases: critical review of current research. Eur J Nutr 2016; 55:1331-43. [PMID: 26932503 DOI: 10.1007/s00394-016-1179-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 02/06/2016] [Indexed: 12/21/2022]
Abstract
Caffeine is a most widely consumed physiological stimulant worldwide, which is consumed via natural sources, such as coffee and tea, and now marketed sources such as energy drinks and other dietary supplements. This wide use has led to concerns regarding the safety of caffeine and its proposed beneficial role in alertness, performance and energy expenditure and side effects in the cardiovascular system. The question remains "Which dose is safe?", as the population does not appear to adhere to the strict guidelines listed on caffeine consumption. Studies in humans and animal models yield controversial results, which can be explained by population, type and dose of caffeine and low statistical power. This review will focus on comprehensive and critical review of the current literature and provide an avenue for further study.
Collapse
Affiliation(s)
- Anthony Zulli
- Centre for Chronic Disease (CCD), College of Health and Biomedicine, Victoria University, Melbourne, VIC, Australia
| | - Renee M Smith
- Centre for Chronic Disease (CCD), College of Health and Biomedicine, Victoria University, Melbourne, VIC, Australia
| | - Peter Kubatka
- Department of Medical Biology, Jessenius Faculty of Medicine, Comenius University in Bratislava, Martin, Slovakia
| | - Jan Novak
- 2nd Department of Internal Medicine, St. Anne's University Hospital and Masaryk University, Brno, Czech Republic.,Department of Physiology, Masaryk University, Brno, Czech Republic
| | - Yoshio Uehara
- Division of Clinical Nutrition, Faculty of Home Economics, Kyoritsu Women's University, Tokyo, Japan
| | - Hayley Loftus
- Centre for Chronic Disease (CCD), College of Health and Biomedicine, Victoria University, Melbourne, VIC, Australia
| | - Tawar Qaradakhi
- Centre for Chronic Disease (CCD), College of Health and Biomedicine, Victoria University, Melbourne, VIC, Australia
| | - Miroslav Pohanka
- Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | | | | | - Jan Klimas
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University, Odborarov 10, 832 32, Bratislava, Slovak Republic
| | - Alan Hayes
- Centre for Chronic Disease (CCD), College of Health and Biomedicine, Victoria University, Melbourne, VIC, Australia
| | - Giampiero La Rocca
- Human Anatomy Section, Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Palermo, Italy.,Euro-Mediterranean Institute of Science and Technology (IEMEST), Palermo, Italy
| | - Miroslav Soucek
- 2nd Department of Internal Medicine, St. Anne's University Hospital and Masaryk University, Brno, Czech Republic
| | - Peter Kruzliak
- Laboratory of Structural Biology and Proteomics, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Palackeho tr 1/1946, Brno, 612 42, Czech Republic.
| |
Collapse
|
43
|
Varani K, Vincenzi F, Targa M, Ravani A, Bastia E, Storoni L, Brambilla S, Almirante N, Impagnatiello F. Repeated Dosing with NCX1404, a Nitric Oxide-Donating Pregabalin, Re-establishes Normal Nociceptive Responses in Mice with Streptozotocin-Induced Painful Diabetic Neuropathy. J Pharmacol Exp Ther 2016; 357:240-7. [PMID: 26907623 DOI: 10.1124/jpet.115.230193] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/17/2016] [Indexed: 12/21/2022] Open
Abstract
NCX1404 [(3S)-5-methyl-3-(((1-(4-(nitrooxy)butanoyloxy)ethoxy)carbonylamino) methyl)hexanoic acid] is a novel nitric oxide (NO)-donating pregabalin that is readily absorbed and processed in vivo to pregabalin and NO. We determined the antiallodynic response of NCX1404 after acute or after 7, 14, and 21 days of repeated daily oral dosing in mice with streptozotocin (STZ)-induced painful diabetic neuropathy (PDN). Pregabalin and its combination with the NO donor isosorbide mononitrate (ISMN) were used for comparison. The blood levels of pregabalin and nitrites, used as surrogate marker of NO release, after NCX1404 or pregabalin dosing were monitored in parallel experiments using liquid chromatography with tandem mass spectrometry (LC-MS/MS). NCX1404 and pregabalin resulted in similar pregabalin levels as it was their antiallodynic activity after acute dosing in STZ mice. However, NCX1404 resulted in disease-modifying properties when administered daily for 21 days, as indicated by the time- and dose-dependent reversal of STZ-induced mechanical allodynia (paw withdrawal threshold [PWT]Veh_21d= 1.3 ± 0.15 g for vehicle; PWTNCX1404_21d= 1.4 ± 0.5 g, 2.9 ± 0.2 g* and 4.1 ± 0.2 g*, respectively for 19, 63, and 190μmol/kg, oral gavage [PO] of NCX1404; *P< 0.05 versus vehicle). This effect was not shared by pregabalin at equimolar doses (190μmol/kg, PO, PWTPregab_21d= 1.4 ± 0.1 g*, *P< 0.05 versus equimolar NCX1404). In addition, the NO donor ISMN (52.3μmol/kg, PO) alone or combined with pregabalin (63μmol/kg) was active at 7 days (PWTVeh_7d= 1.7 ± 0.16 g; PWTISMN_7d= 3.9 ± 0.34 g*; PWTPregab_7d= 1.3 ± 0.07 g; PWTISMN+pregab_7d= 3.8 ± 0.29 g*; *P< 0.05) but not at later time points. The long-term effect of NCX1404 was independent of residual drug exposure and lasted for several days after the treatment was stopped. In summary, like pregabalin, NCX1404 is an effective antiallodynic agent. Differently from pregabalin, repeated dosing of NCX1404 re-established normal nociceptive responses in STZ-induced PDN in mice.
Collapse
Affiliation(s)
- Katia Varani
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, Ferrara, Italy (K.V., F.V., M.T., A.R.); Nicox Research Institute, Bresso, Milano, Italy (E.B., L.S., S.B., N.A., F.I.)
| | - Fabrizio Vincenzi
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, Ferrara, Italy (K.V., F.V., M.T., A.R.); Nicox Research Institute, Bresso, Milano, Italy (E.B., L.S., S.B., N.A., F.I.)
| | - Martina Targa
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, Ferrara, Italy (K.V., F.V., M.T., A.R.); Nicox Research Institute, Bresso, Milano, Italy (E.B., L.S., S.B., N.A., F.I.)
| | - Annalisa Ravani
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, Ferrara, Italy (K.V., F.V., M.T., A.R.); Nicox Research Institute, Bresso, Milano, Italy (E.B., L.S., S.B., N.A., F.I.)
| | - Elena Bastia
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, Ferrara, Italy (K.V., F.V., M.T., A.R.); Nicox Research Institute, Bresso, Milano, Italy (E.B., L.S., S.B., N.A., F.I.)
| | - Laura Storoni
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, Ferrara, Italy (K.V., F.V., M.T., A.R.); Nicox Research Institute, Bresso, Milano, Italy (E.B., L.S., S.B., N.A., F.I.)
| | - Stefania Brambilla
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, Ferrara, Italy (K.V., F.V., M.T., A.R.); Nicox Research Institute, Bresso, Milano, Italy (E.B., L.S., S.B., N.A., F.I.)
| | - Nicoletta Almirante
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, Ferrara, Italy (K.V., F.V., M.T., A.R.); Nicox Research Institute, Bresso, Milano, Italy (E.B., L.S., S.B., N.A., F.I.)
| | - Francesco Impagnatiello
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, Ferrara, Italy (K.V., F.V., M.T., A.R.); Nicox Research Institute, Bresso, Milano, Italy (E.B., L.S., S.B., N.A., F.I.)
| |
Collapse
|
44
|
Paeoniflorin exerts analgesic and hypnotic effects via adenosine A1 receptors in a mouse neuropathic pain model. Psychopharmacology (Berl) 2016; 233:281-93. [PMID: 26514553 DOI: 10.1007/s00213-015-4108-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 10/05/2015] [Indexed: 10/22/2022]
Abstract
RATIONAL Neuropathic pain is frequently comorbid with sleep disturbances. Paeoniflorin, a main active compound of total glucosides of paeony, has been well documented to exhibit neuroprotective bioactivity. OBJECTIVE The present study evaluated effects of paeoniflorin on neuropathic pain and associated insomnia and the mechanisms involved. METHODS The analgesic and hypnotic effects of paeoniflorin were measured by mechanical threshold and thermal latency, electroencephalogram (EEG) and electromyogram, and c-Fos expression in a neuropathic pain insomnia model. RESULTS The data revealed that paeoniflorin (50 or 100 mg/kg, i.p.) significantly increased the mechanical threshold and prolonged the thermal latency in partial sciatic nerve ligation (PSNL) mice. Meanwhile, paeoniflorin increased non-rapid eye movement (NREM) sleep amount and concomitantly decreased wakefulness time. However, pretreatment with l,3-dimethy-8-cyclopenthylxanthine, an adenosine A1 receptor (R, A1R) antagonist, abolished the analgesic and hypnotic effects of paeoniflorin. Moreover, paeoniflorin at 100 mg/kg failed to change mechanical threshold and thermal latency and NREM sleep in A1R knockout PSNL mice. Immunohistochemical study showed that paeoniflorin inhibited c-Fos overexpression induced by PSNL in the anterior cingulate cortex and ventrolateral periaqueductal gray. CONCLUSIONS The present findings indicated that paeoniflorin exerted analgesic and hypnotic effects via adenosine A1Rs and might be of potential use in the treatment of neuropathic pain and associated insomnia.
Collapse
|
45
|
Jacobson KA, Müller CE. Medicinal chemistry of adenosine, P2Y and P2X receptors. Neuropharmacology 2015; 104:31-49. [PMID: 26686393 DOI: 10.1016/j.neuropharm.2015.12.001] [Citation(s) in RCA: 184] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 11/30/2015] [Accepted: 12/01/2015] [Indexed: 12/13/2022]
Abstract
Pharmacological tool compounds are now available to define action at the adenosine (ARs), P2Y and P2X receptors. We present a selection of the most commonly used agents to study purines in the nervous system. Some of these compounds, including A1 and A3 AR agonists, P2Y1R and P2Y12R antagonists, and P2X3, P2X4 and P2X7 antagonists, are potentially of clinical use in treatment of disorders of the nervous system, such as chronic pain, neurodegeneration and brain injury. Agonists of the A2AAR and P2Y2R are already used clinically, P2Y12R antagonists are widely used antithrombotics and an antagonist of the A2AAR is approved in Japan for treating Parkinson's disease. The selectivity defined for some of the previously introduced compounds has been revised with updated pharmacological characterization, for example, various AR agonists and antagonists were deemed A1AR or A3AR selective based on human data, but species differences indicated a reduction in selectivity ratios in other species. Also, many of the P2R ligands still lack bioavailability due to charged groups or hydrolytic (either enzymatic or chemical) instability. X-ray crystallographic structures of AR and P2YRs have shifted the mode of ligand discovery to structure-based approaches rather than previous empirical approaches. The X-ray structures can be utilized either for in silico screening of chemically diverse libraries for the discovery of novel ligands or for enhancement of the properties of known ligands by chemical modification. Although X-ray structures of the zebrafish P2X4R have been reported, there is scant structural information about ligand recognition in these trimeric ion channels. In summary, there are definitive, selective agonists and antagonists for all of the ARs and some of the P2YRs; while the pharmacochemistry of P2XRs is still in nascent stages. The therapeutic potential of selectively modulating these receptors is continuing to gain interest in such fields as cancer, inflammation, pain, diabetes, ischemic protection and many other conditions. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
Collapse
Key Words
- 2-MeSADP, (PubChem CID: 121990)
- A-740003, (PubChem CID: 23232014)
- ATP
- Agonists
- Antagonists
- DPCPX, (PubChem CID: 1329)
- GPCR
- IB-MECA, (PubChem CID: 123683)
- Ion channel
- LUF6000, (PubChem CID: 11711282)
- MRS2500, (PubChem CID: 44448831)
- Nucleosides
- Nucleotides
- PPTN, (PubChem CID: 42611190)
- PSB-1114, (PubChem CID: 52952605)
- PSB-603, (PubChem CID: 44185871)
- SCH442416, (PubChem CID: 10668061)
Collapse
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, 20892, Bethesda, USA.
| | - Christa E Müller
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, Bonn, Germany
| |
Collapse
|
46
|
Abstract
There is a brief introductory summary of purinergic signaling involving ATP storage, release, and ectoenzymatic breakdown, and the current classification of receptor subtypes for purines and pyrimidines. The review then describes purinergic mechanosensory transduction involved in visceral, cutaneous, and musculoskeletal nociception and on the roles played by receptor subtypes in neuropathic and inflammatory pain. Multiple purinoceptor subtypes are involved in pain pathways both as an initiator and modulator. Activation of homomeric P2X3 receptors contributes to acute nociception and activation of heteromeric P2X2/3 receptors appears to modulate longer-lasting nociceptive sensitivity associated with nerve injury or chronic inflammation. In neuropathic pain activation of P2X4, P2X7, and P2Y12 receptors on microglia may serve to maintain nociceptive sensitivity through complex neural-glial cell interactions and antagonists to these receptors reduce neuropathic pain. Potential therapeutic approaches involving purinergic mechanisms will be discussed.
Collapse
|
47
|
Abstract
Adenosine is an ubiquitous nucleoside involved in various physiological and pathological functions by stimulating A1, A2A, A2B and A3 adenosine receptors (ARs). Allosteric enhancers to A1ARs may represent novel therapeutic agents because they increase the activity of these receptors by mediating a shift to their active form in the A1AR-G protein ternary complex. In this manner, they are able to amplify the action of endogenous adenosine, which is produced in high concentrations under conditions of metabolic stress. A1AR allosteric enhancers could be used as a justifiable alternative to the exogenous agonists that are characterized by receptor desensitization and downregulation. In this review, an analysis of some of the most interesting allosteric modulators of A1ARs has been reported.
Collapse
|
48
|
Synthesis and biological evaluation of a new series of 2-amino-3-aroyl thiophene derivatives as agonist allosteric modulators of the A1 adenosine receptor. A position-dependent effect study. Eur J Med Chem 2015; 101:185-204. [PMID: 26141910 DOI: 10.1016/j.ejmech.2015.06.041] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 06/05/2015] [Accepted: 06/22/2015] [Indexed: 11/20/2022]
Abstract
The 2-amino-3-(p-chlorobenzoyl)thiophene scaffold has been widely employed as a pharmacophore for the identification of small molecules acting as allosteric modulators at the adenosine A1 receptor. A new series of 2-amino-3-(p-chlorobenzoyl)-4-benzyl-5-arylthiophene derivatives, characterized by the absence as well as the presence of electron-releasing or electron-withdrawing groups on the phenyl ring at the 4- and 5-positions of the thiophene ring, were identified as positive allosteric enhancers at the adenosine A1 receptor in binding (saturation, competition and dissociation kinetics) and functional assays. To better understand the positional requirements of substituents on the 2-amino-3-(p-chlorobenzoyl)thiophene core, the corresponding regioisomeric 4-aryl-5-benzylthiophene analogues were synthesized and found to possess reduced allosteric enhancer activity.
Collapse
|
49
|
Imlach WL, Bhola RF, May LT, Christopoulos A, Christie MJ. A Positive Allosteric Modulator of the Adenosine A1 Receptor Selectively Inhibits Primary Afferent Synaptic Transmission in a Neuropathic Pain Model. Mol Pharmacol 2015; 88:460-8. [DOI: 10.1124/mol.115.099499] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 06/23/2015] [Indexed: 11/22/2022] Open
|
50
|
The purinergic system and glial cells: emerging costars in nociception. BIOMED RESEARCH INTERNATIONAL 2014; 2014:495789. [PMID: 25276794 PMCID: PMC4168030 DOI: 10.1155/2014/495789] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 07/08/2014] [Indexed: 12/23/2022]
Abstract
It is now well established that glial cells not only provide mechanical and trophic support to neurons but can directly contribute to neurotransmission, for example, by release and uptake of neurotransmitters and by secreting pro- and anti-inflammatory mediators. This has greatly changed our attitude towards acute and chronic disorders, paving the way for new therapeutic approaches targeting activated glial cells to indirectly modulate and/or restore neuronal functions. A deeper understanding of the molecular mechanisms and signaling pathways involved in neuron-to-glia and glia-to-glia communication that can be pharmacologically targeted is therefore a mandatory step toward the success of this new healing strategy. This holds true also in the field of pain transmission, where the key involvement of astrocytes and microglia in the central nervous system and satellite glial cells in peripheral ganglia has been clearly demonstrated, and literally hundreds of signaling molecules have been identified. Here, we shall focus on one emerging signaling system involved in the cross talk between neurons and glial cells, the purinergic system, consisting of extracellular nucleotides and nucleosides and their membrane receptors. Specifically, we shall summarize existing evidence of novel “druggable” glial purinergic targets, which could help in the development of innovative analgesic approaches to chronic pain states.
Collapse
|