scholarly journals Molecular Cloning and Pharmacological Characterization of Two Novel GnRH Receptors in the Lamprey (Petromyzon marinus)

Endocrinology ◽  
2012 ◽  
Vol 153 (7) ◽  
pp. 3345-3356 ◽  
Author(s):  
Nerine T. Joseph ◽  
Allisan Aquilina-Beck ◽  
Caryn MacDonald ◽  
Wayne A. Decatur ◽  
Jeffrey A. Hall ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Intracellular Signaling ◽  
Inositol Phosphate ◽  
Sea Lamprey ◽  
Structural Features ◽  
Receptor Subtypes ◽  
Pharmacological Characterization ◽  
Functional Studies ◽  
Gnrh Receptors ◽  
Precursor Transcript

This paper reports the identification, expression, binding kinetics, and functional studies of two novel type III lamprey GnRH receptors (lGnRH-R-2 and lGnRH-R-3) in the sea lamprey, a basal vertebrate. These novel GnRH receptors share the structural features and amino acid motifs common to other known gnathostome GnRH receptors. The ligand specificity and activation of intracellular signaling studies showed ligands lGnRH-II and -III induced an inositol phosphate (IP) response at lGnRH-R-2 and lGnRH-R-3, whereas the ligand lGnRH-I did not stimulate an IP response. lGnRH-II was a more potent activator of lGnRH-R-3 than lGnRH-III. Stimulation of lGnRH-R-2 and lGnRH-R-3 testing all three lGnRH ligands did not elicit a cAMP response. lGnRH-R-2 has a higher binding affinity in response to lGnRH-III than lGnRH-II, whereas lGnRH-R-3 has a higher binding affinity in response to lGnRH-II than IGnRH-III. lGnRH-R-2 precursor transcript was detected in a wide variety of tissues including the pituitary whereas lGnRH-R-3 precursor transcript was not as widely expressed and primarily expressed in the brain and eye of male and female lampreys. From our phylogenetic analysis, we propose that lGnRH-R-1 evolved from a common ancestor of all vertebrate GnRH receptors and lGnRH-R-2 and lGnRH-R-3 likely occurred due to a gene duplication within the lamprey lineage. In summary, we propose from our findings of receptor subtypes in the sea lamprey that the evolutionary recruitment of specific pituitary GnRH receptor subtypes for particular physiological functions seen in later evolved vertebrates was an ancestral character that first arose in a basal vertebrate.

scholarly journals Highly Selective, Amine-Derived Cannabinoid Receptor 2 Probes

2019 ◽  
Author(s):  
Matthias V. Westphal ◽  
Roman C. Sarott ◽  
Elisabeth A. Zirwes ◽  
Anja Osterwald ◽  
Wolfgang Guba ◽  
...  
Keyword(s):  
Cannabinoid Receptor ◽  
Synthetic Cannabinoids ◽  
Structural Features ◽  
Pharmacological Characterization ◽  
Cannabinoid Receptor 2 ◽  
Functional Studies ◽  
Design And Synthesis ◽  
Downstream Effects ◽  
G Protein Coupled

The endocannabinoid (eCB) system is implied in various human diseases ranging from central nervous system to autoimmune disorders. Cannabinoid receptor 2 (CB<sub>2</sub>R) is an integral component of the eCB system. Yet, the downstream effects elicited by this G protein-coupled receptor upon binding of endogenous or synthetic ligands are insufficiently understood—likely due to the limited arsenal of reliable biological and chemical tools. Herein, we report the design and synthesis of CB<sub>2</sub>R-selective cannabinoids along with their <i>in vitro</i> pharmacological characterization (binding and functional studies). They combine structural features of HU-308 and AM841 to give chimeric ligands that emerge as potent CB<sub>2</sub>R agonists with high selectivity over the closely related cannabinoid receptor 1 (CB<sub>1</sub>R). The synthesis work includes convenient preparation of substituted resorcinols often found in cannabinoids. The utility of the synthetic cannabinoids in this study is showcased by preparation of the most selective high-affinity fluorescent probe for CB<sub>2</sub>R to date.

scholarly journals Highly Selective, Amine-Derived Cannabinoid Receptor 2 Probes

2019 ◽  
Author(s):  
Matthias V. Westphal ◽  
Roman C. Sarott ◽  
Elisabeth A. Zirwes ◽  
Anja Osterwald ◽  
Wolfgang Guba ◽  
...  
Keyword(s):  
Cannabinoid Receptor ◽  
Synthetic Cannabinoids ◽  
Structural Features ◽  
Pharmacological Characterization ◽  
Cannabinoid Receptor 2 ◽  
Functional Studies ◽  
Design And Synthesis ◽  
Downstream Effects ◽  
G Protein Coupled

The endocannabinoid (eCB) system is implied in various human diseases ranging from central nervous system to autoimmune disorders. Cannabinoid receptor 2 (CB<sub>2</sub>R) is an integral component of the eCB system. Yet, the downstream effects elicited by this G protein-coupled receptor upon binding of endogenous or synthetic ligands are insufficiently understood—likely due to the limited arsenal of reliable biological and chemical tools. Herein, we report the design and synthesis of CB<sub>2</sub>R-selective cannabinoids along with their <i>in vitro</i> pharmacological characterization (binding and functional studies). They combine structural features of HU-308 and AM841 to give chimeric ligands that emerge as potent CB<sub>2</sub>R agonists with high selectivity over the closely related cannabinoid receptor 1 (CB<sub>1</sub>R). The synthesis work includes convenient preparation of substituted resorcinols often found in cannabinoids. The utility of the synthetic cannabinoids in this study is showcased by preparation of the most selective high-affinity fluorescent probe for CB<sub>2</sub>R to date.

scholarly journals Cloning and Characterization of a Functional Type II Gonadotropin-Releasing Hormone Receptor with a Lengthy Carboxy-Terminal Tail from an Ancestral Vertebrate, the Sea Lamprey

Endocrinology ◽  
2005 ◽  
Vol 146 (8) ◽  
pp. 3351-3361 ◽  
Author(s):  
Matthew R. Silver ◽  
Nathaniel V. Nucci ◽  
Adam R. Root ◽  
Karen L. Reed ◽  
Stacia A. Sower
Keyword(s):  
Inositol Phosphate ◽  
Sea Lamprey ◽  
Structural Features ◽  
Gnrh Receptor ◽  
Type Ii ◽  
Functional Type ◽  
Vertebrate Lineage ◽  
Functional Features ◽  
Full Length Transcript ◽  
Carboxy Terminal

Abstract A full-length transcript encoding a functional type II GnRH receptor was cloned from the pituitary of the sea lamprey, Petromyzon marinus. The current study is the first to identify a pituitary GnRH receptor transcript in an agnathan, which is the oldest vertebrate lineage. The cloned receptor retains the conserved structural features and amino acid motifs of other known GnRH receptors and notably includes a C-terminal intracellular tail of approximately 120 amino acids, the longest C-terminal tail of any vertebrate GnRH receptor identified to date. The lamprey GnRH receptor was shown to activate the inositol phosphate (IP) signaling system; stimulation with either lamprey GnRH-I or lamprey GnRH-III led to dose-dependent responses in transiently transfected COS7 cells. Furthermore, analyses of serially truncated lamprey GnRH receptor mutants indicate perturbations of the C-terminal tail disrupts IP accumulation, however, the tailless lamprey GnRH receptor was not only functional but was also capable of stimulating IP levels equal to wild type. Expression of the receptor transcript was demonstrated in the pituitary and testes using RT-PCR, whereas in situ hybridization showed expression and localization of the transcript in the proximal pars distalis of the pituitary. The phylogenetic placement and structural and functional features of this GnRH receptor suggest that it is representative of an ancestral GnRH receptor. In addition to having an important role in lamprey reproductive processes, the extensive C-terminal tail of this lamprey GnRH receptor may have great significance for understanding the evolutionary change of this vital structural feature within the GnRH receptor family.

Bronchospasmolytic and Adenosine Binding Activity of 8- (Proline / Pyrazole)-Substituted Xanthine Derivatives

2020 ◽  
Vol 17 ◽  
Author(s):  
Sneha Singh ◽  
Madhwi Ojha ◽  
Divya Yadav ◽  
Sonja Kachler ◽  
Karl-Norbert Klotz ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Radioligand Binding ◽  
Binding Activity ◽  
Receptor Subtypes ◽  
Significant Protection ◽  
Binding Studies ◽  
Standard Drug ◽  
Xanthine Derivatives ◽  
Radioligand Binding Studies ◽  
Micromolar Range

Background: ABSTRACT: Background: 8-Phenyltheophylline derivatives exhibit prophylactic effects at a specific dose but do not produce the cardiovascular or emetic side effects associated with xanthines, thereby exhibiting unique characteristics of potential therapeutic importance. Methods: Novel series of 8-(proline/pyrazole)-substituted xanthine analogs has been synthesized. The affinity and selectivity of compounds to adenosine receptors have been assessed by radioligand binding studies. The synthesized compounds also showed good bronchospasmolytic properties (increased onset of bronchospasm; decreased duration of jerks) with 100% survival of animals in comparison to the standard drug. Besides, compound 8f & 9f showed good binding affinity in comparison to other synthesized compounds in the micromolar range. Results: The maximum binding affinity of these compounds was observed for A2B receptors, which is ~ 7 or 10 times higher as compared to A1, A2A and A3 receptors. The newly synthesized derivatives 8f, 9a-f, 17g-m, and 18g-m displayed significant protection against histamine aerosol induced bronchospasm in guinea pigs. Conclusion: Newly synthesized proline/pyrazole based xanthines compounds showed a satisfactory binding affinity for adenosine receptor subtypes. Replacement or variation of substituted proline ring with substituted pyrazole scaffold at 8thposition of xanthine moiety resulted in the reduction of adenosine binding affinity and bronchospasmolytic effects.

Effect of SR-49059, a vasopressin V1a antagonist, on human vascular smooth muscle cells

1995 ◽  
Vol 268 (1) ◽  
pp. H404-H410 ◽  
Author(s):  
C. Serradeil-Le Gal ◽  
J. M. Herbert ◽  
C. Delisee ◽  
P. Schaeffer ◽  
D. Raufaste ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Specific Binding ◽  
Muscle Cells ◽  
Maximal Response ◽  
Receptor Subtypes ◽  
Functional Studies ◽  
Antagonist Binding

The effects of SR-49059, a new nonpeptide and selective arginine vasopressin (AVP) V1a antagonist, were investigated in binding and functional studies on cultured human aortic vascular smooth muscle cells (VSMC). Characterization of human vascular V1a receptors, using a specific V1a radioiodinated ligand, showed that [125I]-linear AVP antagonist binding to human VSMC membranes was time dependent, reversible, and saturable. A single population of high-affinity binding sites (apparent equilibrium dissociation constant = 15 +/- 6 pM; maximum binding density = 36 +/- 5 fmol/mg protein, i.e., approximately 3,000 sites/cell) with the expected V1a profile was identified. Exposure of these cells to AVP dose-dependently produced cytosolic free [Ca2+] increase [AVP concentration required to obtain a half-maximal response (EC50) = 23 +/- 9 nM] and proliferation (EC50 = 3.2 +/- 0.5 nM). SR-49059 strongly and stereospecifically inhibited [125I]-linear AVP antagonist binding to VSMC V1a receptors [inhibition constant (Ki) = 1.4 +/- 0.3 nM], AVP-evoked Ca2+ increase [concentration of inhibitor required to obtain 50% inhibition of specific binding (IC50) = 0.41 +/- 0.06 nM], and the mitogenic effects induced by 100 nM AVP (IC50 = 0.83 +/- 0.04 nM). OPC-21268, another nonpeptide V1a antagonist, was more than two orders of magnitude less potent than SR-49059 in these models. However, the consistent affinity (Ki = 138 +/- 21 nM) and activity found with OPC-21268 on human VSMC in comparison with the inactivity already observed for other human V1a receptors (liver, platelets, adrenals, and uterus) strongly suggested the existence of human AVP V1a-receptor subtypes.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Angiotensin III Activates Nuclear Transcription Factor-κB in Cultured Mesangial Cells Mainly via AT2Receptors: Studies with AT1Receptor-Knockout Mice

2002 ◽  
Vol 13 (5) ◽  
pp. 1162-1171
Author(s):  
Óscar Lorenzo ◽  
Marta Ruiz-Ortega ◽  
Yusuke Suzuki ◽  
Mónica Rupérez ◽  
Vanesa Esteban ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Knockout Mice ◽  
Intracellular Signaling ◽  
Mesangial Cells ◽  
Renin Angiotensin System ◽  
Nuclear Factor Κb ◽  
Receptor Subtypes ◽  
Receptor Antagonists ◽  
Signaling Mechanism ◽  
Amino Terminal

ABSTRACT. Nuclear factor-κB (NF-κB) regulates many genes involved in renal pathophysiologic processes. It was previously demonstrated that angiotensin II (AngII) and its amino-terminal degradation product AngIII activate NF-κB in mesangial cells. However, which are the Ang receptor subtypes involved in the NF-κB pathway and whether these Ang peptides act through the same or different receptors in mesangial cells have not been evaluated. Under the culture conditions used, quiescent rat mesangial cells expressed both AT1and AT2receptors. To investigate the receptors involved in the NF-κB pathway, two different approaches were used,i.e., pharmacologic studies, using specific AT1and AT2receptor antagonists and agonists, and studies in AT1receptor-knockout mice. In cultured rat mesangial cells, both AT1and AT2receptor antagonists inhibited AngII-induced NF-κB DNA binding activity, whereas NF-κB activation elicited by AngIII was mainly blocked by the AT2receptor antagonist. Similar results were observed for cytosolic IκBα degradation. An AT2receptor agonist also activated NF-κB. In AT1receptor-knockout murine mesangial cells, AngIII and AngII increased NF-κB activity and degraded cytosolic IκBα; both processes were blocked by the AT2receptor antagonist. These data demonstrate that, in mesangial cells, NF-κB activation is mediated by AT1and AT2receptors, suggesting a novel intracellular signaling mechanism for AT2receptors in the kidney. Some differences in Ang peptide receptor-mediated responses were also observed. AngII activates NF-κB via AT1and AT2receptors, whereas AngIII acts mainly via AT2receptors. These results suggest the potential involvement of the AngIII/AT2receptor/NF-κB pathway in pathophysiologic processes in the kidney and provide a better understanding of the renin-angiotensin system.

Structure and functions of T-cell immunoglobulin-domain and mucin- domain protein 3 in cancer

2021 ◽  
Vol 28 ◽  
Author(s):  
Xinjie Lu
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cancer Immunotherapy ◽  
Intracellular Signaling ◽  
Checkpoint Inhibitors ◽  
Cell Types ◽  
Structural Features ◽  
Type I ◽  
Potential Biomarker ◽  
Tim Proteins

Background: T-cell immunoglobulin (Ig)-domain and mucin-domain (TIM) proteins represent a family of receptors expressed on T-cells that play essential cellular immunity roles. The TIM proteins span across the membrane belonging to type I transmembrane proteins. The N terminus contains an Ig-like V-type domain and a Ser/Thr-rich mucin stalk as a co-inhibitory receptor. The C-terminal tail oriented toward the cytosol predominantly mediates intracellular signaling. Methods: This review discusses the structural features and functions of TIM-3, specifically on its role in mediating immune responses in different cell types, and the rationale for TIM-3-targeted cancer immunotherapy. Results: TIM-3 has gained significant importance to be a potential biomarker in cancer immunotherapy. It has been shown that blockade with checkpoint inhibitors promotes anti-tumor immunity and inhibits tumor growth in several preclinical tumor models. Conclusion: TIM-3 is an immune regulating molecule expressed on several cell types, including IFNγ-producing T-cells, FoxP3+ Treg cells, and innate immune cells. The roles of TIM-3 in immunosuppression support its merit as a target for cancer immunotherapy.

scholarly journals I8-arachnotocin–an arthropod-derived G protein-biased ligand of the human vasopressin V2 receptor

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Leopold Duerrauer ◽  
Edin Muratspahić ◽  
Jasmin Gattringer ◽  
Peter Keov ◽  
Helen C. Mendel ◽  
...  
Keyword(s):  
G Protein ◽  
Partial Agonist ◽  
Receptor Subtypes ◽  
Signaling System ◽  
Pharmacological Characterization ◽  
Metaseiulus Occidentalis ◽  
Physiological Relevance ◽  
V2 Receptor ◽  
Second Messenger Signaling ◽  
The Individual

AbstractThe neuropeptides oxytocin (OT) and vasopressin (VP) and their G protein-coupled receptors OTR, V1aR, V1bR, and V2R form an important and widely-distributed neuroendocrine signaling system. In mammals, this signaling system regulates water homeostasis, blood pressure, reproduction, as well as social behaviors such as pair bonding, trust and aggression. There exists high demand for ligands with differing pharmacological profiles to study the physiological and pathological functions of the individual receptor subtypes. Here, we present the pharmacological characterization of an arthropod (Metaseiulus occidentalis) OT/VP-like nonapeptide across the human OT/VP receptors. I8-arachnotocin is a full agonist with respect to second messenger signaling at human V2R (EC50 34 nM) and V1bR (EC50 1.2 µM), a partial agonist at OTR (EC50 790 nM), and a competitive antagonist at V1aR [pA2 6.25 (558 nM)]. Intriguingly, I8-arachnotocin activated the Gαs pathway of V2R without recruiting either β-arrestin-1 or β-arrestin-2. I8-arachnotocin might thus be a novel pharmacological tool to study the (patho)physiological relevance of β-arrestin-1 or -2 recruitment to the V2R. These findings furthermore highlight arthropods as a novel, vast and untapped source for the discovery of novel pharmacological probes and potential drug leads targeting neurohormone receptors.

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