Current Status in the Design and Development of Agonists and Antagonists of Adenosine A3 Receptor as Potential Therapeutic Agents

2019 ◽  
Vol 25 (25) ◽  
pp. 2772-2787 ◽  
Author(s):  
Raghu P. Mailavaram ◽  
Omar H.A. Al-Attraqchi ◽  
Supratik Kar ◽  
Shinjita Ghosh

Adenosine receptors (ARs) belongs to the family of G-protein coupled receptors (GPCR) that are responsible for the modulation of a wide variety of physiological functions. The ARs are also implicated in many diseases such as cancer, arthritis, cardiovascular and renal diseases. The adenosine A3 receptor (A3AR) has emerged as a potential drug target for the progress of new and effective therapeutic agents for the treatment of various pathological conditions. This receptor’s involvement in many diseases and its validity as a target has been established by many studies. Both agonists and antagonists of A3AR have been extensively investigated in the last decade with the goal of developing novel drugs for treating diseases related to immune disorders, inflammation, cancer, and others. In this review, we shall focus on the medicinal chemistry of A3AR ligands, exploring the diverse chemical classes that have been projected as future leading drug candidates. Also, the recent advances in the therapeuetic applications of A3AR ligands are highlighted.

Author(s):  
Gabriele Stephan ◽  
Niklas Ravn-Boess ◽  
Dimitris G Placantonakis

Abstract Members of the adhesion family of G protein-coupled receptors (GPCRs) have received attention for their roles in health and disease, including cancer. Over the past decade, several members of the family have been implicated in the pathogenesis of glioblastoma. Here, we discuss the basic biology of adhesion GPCRs and review in detail specific members of the receptor family with known functions in glioblastoma. Finally, we discuss the potential use of adhesion GPCRs as novel treatment targets in neuro-oncology.


2014 ◽  
Vol 34 (4) ◽  
pp. 856-892 ◽  
Author(s):  
Dong Guo ◽  
Julia M. Hillger ◽  
Adriaan P. IJzerman ◽  
Laura H. Heitman

Blood ◽  
2009 ◽  
Vol 113 (20) ◽  
pp. 4942-4954 ◽  
Author(s):  
Yotis A. Senis ◽  
Michael G. Tomlinson ◽  
Stuart Ellison ◽  
Alexandra Mazharian ◽  
Jenson Lim ◽  
...  

Abstract Platelets play a fundamental role in hemostasis and thrombosis. They are also involved in pathologic conditions resulting from blocked blood vessels, including myocardial infarction and ischemic stroke. Platelet adhesion, activation, and aggregation at sites of vascular injury are regulated by a diverse repertoire of tyrosine kinase–linked and G protein–coupled receptors. Src family kinases (SFKs) play a central role in initiating and propagating signaling from several platelet surface receptors; however, the underlying mechanism of how SFK activity is regulated in platelets remains unclear. CD148 is the only receptor-like protein tyrosine phosphatase identified in platelets to date. In the present study, we show that mutant mice lacking CD148 exhibited a bleeding tendency and defective arterial thrombosis. Basal SFK activity was found to be markedly reduced in CD148-deficient platelets, resulting in a global hyporesponsiveness to agonists that signal through SFKs, including collagen and fibrinogen. G protein–coupled receptor responses to thrombin and other agonists were also marginally reduced. These results highlight CD148 as a global regulator of platelet activation and a novel antithrombotic drug target.


2021 ◽  
Vol 13 (1) ◽  
pp. 63-90
Author(s):  
Joshua W Conner ◽  
Daniel P Poole ◽  
Manuela Jörg ◽  
Nicholas A Veldhuis

G protein-coupled receptors (GPCRs) are essential signaling proteins and tractable therapeutic targets. To develop new drug candidates, GPCR drug discovery programs require versatile, sensitive pharmacological tools for ligand binding and compound screening. With the availability of new imaging modalities and proximity-based ligand binding technologies, fluorescent ligands offer many advantages and are increasingly being used, yet labeling small molecules remains considerably more challenging relative to peptides. Focusing on recent fluorescent small molecule studies for family A GPCRs, this review addresses some of the key challenges, synthesis approaches and structure–activity relationship considerations, and discusses advantages of using high-resolution GPCR structures to inform conjugation strategies. While no single approach guarantees successful labeling without loss of affinity or selectivity, the choice of fluorophore, linker type and site of attachment have proved to be critical factors that can significantly affect their utility in drug discovery programs, and as discussed, can sometimes lead to very unexpected results.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. SCI-45-SCI-45
Author(s):  
Patricia Andrade-Gordon

Abstract Abstract SCI-45 Inappropriate and sustained activation of platelets is a major cause of vascular occlusive diseases such as angina, myocardial infarction, and stroke. The development of thrombi within blood vessels results from the formation of platelet aggregates and fibrin deposits, and heavily depends on the actions of α-thrombin. It is now well recognized that human platelet responses to α-thrombin are mediated by the protease-activated receptors PAR1 and PAR4. Protease-activated receptors (PARs) represent a unique family of seven-transmembrane G-protein-coupled receptors, which are enzymatically cleaved to expose a new extracellular N-terminus that acts as a “tethered” activating ligand. Since the discovery of PAR1 as the major contributor to human platelet aggregation, there has been a keen interest to develop antagonist as potential antithrombotics. However, there have been many issues and challenges in this endeavor. One crucial challenge to the discovery of potent antagonists is the strong entropy advantage offered by the intramolecular binding mechanism of PARs activation, which presents a great disadvantage to a circulating small molecule antagonist. To be an effective therapeutic agent, a PAR1 antagonist not only should bind tightly to the receptor but also possess suitable binding kinetics. Another issue for the discovery of PAR1 antagonists is the preclinical logistics associated with species variability of PAR1 on platelets. Despite these challenges, PAR1 has been an attractive drug target and there has been considerable activity and progress in the discovery and development of PAR1 antagonist as therapeutic agents. The promise of these novel therapeutics is reflected by two antiplatelet PAR1 antagonists in advanced clinical trials. The clinical benefits derived from these agents will be determined by the tight balance between delivering efficacy in the context of thrombotic disease and controlling the bleeding risk. The discussion will focus on the challenges from discovery to development of these great potential opportunities in the prevention of atherothrombotic disease. Disclosures: Andrade-Gordon: Johnson & Johnson: Employment.


1999 ◽  
Vol 79 (4) ◽  
pp. 1193-1226 ◽  
Author(s):  
Shuh Narumiya ◽  
Yukihiko Sugimoto ◽  
Fumitaka Ushikubi

Prostanoids are the cyclooxygenase metabolites of arachidonic acid and include prostaglandin (PG) D2, PGE2, PGF2α, PGI2, and thromboxne A2. They are synthesized and released upon cell stimulation and act on cells in the vicinity of their synthesis to exert their actions. Receptors mediating the actions of prostanoids were recently identified and cloned. They are G protein-coupled receptors with seven transmembrane domains. There are eight types and subtypes of prostanoid receptors that are encoded by different genes but as a whole constitute a subfamily in the superfamily of the rhodopsin-type receptors. Each of the receptors was expressed in cultured cells, and its ligand-binding properties and signal transduction pathways were characterized. Moreover, domains and amino acid residues conferring the specificities of ligand binding and signal transduction are being clarified. Information also is accumulating as to the distribution of these receptors in the body. It is also becoming clear for some types of receptors how expression of their genes is regulated. Furthermore, the gene for each of the eight types of prostanoid receptor has been disrupted, and mice deficient in each type of receptor are being examined to identify and assess the roles played by each receptor under various physiological and pathophysiological conditions. In this article, we summarize these findings and attempt to give an overview of the current status of research on the prostanoid receptors.


2019 ◽  
Vol 25 (26) ◽  
pp. 2792-2807 ◽  
Author(s):  
Pobitra Borah ◽  
Satyendra Deka ◽  
Raghu Prasad Mailavaram ◽  
Pran Kishore Deb

Background: Adenosine mediates various physiological and pathological conditions by acting on its four P1 receptors (A1, A2A, A2B and A3 receptors). Omnipresence of P1 receptors and their activation, exert a wide range of biological activities. Thus, its modulation is implicated in various disorders like Parkinson’s disease, asthma, cardiovascular disorders, cancer etc. Hence these receptors have become an interesting target for the researchers to develop potential therapeutic agents. Number of molecules were designed and developed in the past few years and evaluated for their efficacy in various disease conditions. Objective: The main objective is to provide an overview of new chemical entities which have crossed preclinical studies and reached clinical trials stage following their current status and future prospective. Methods: In this review we discuss current status of the drug candidates which have undergone clinical trials and their prospects. Results: Many chemical entities targeting various subtypes of P1 receptors are patented; twenty of them have crossed preclinical studies and reached clinical trials stage. Two of them viz adenosine and regadenoson are approved by the Food and Drug Administration. Conclusion: This review is an attempt to highlight the current status, progress and probable future of P1 receptor ligands which are under clinical trials as promising novel therapeutic agents and the direction in which research should proceed with a view to come out with novel therapeutic agents.


2002 ◽  
Vol 30 (4) ◽  
pp. 428-432 ◽  
Author(s):  
E. W. Hillhouse ◽  
H. Randeva ◽  
G. Ladds ◽  
D. Grammatopoulos

Corticotropin-releasing hormone (CRH) and related peptides (urocortins, sauvagine, urotensin) play a central role in the co-ordination of autonomic, behavioural, cardiovascular, immune and endocrine responses to stressful stimuli. Their actions are mediated through activation of two types of G-protein-coupled receptors encoded by separate genes. In this review we focus on the diverse structural and functional characteristics of the family of CRH-like peptides and their receptors.


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