scholarly journals Adenosine A2A and A3 Receptors Are Able to Interact with Each Other. A Further Piece in the Puzzle of Adenosine Receptor-Mediated Signaling

2020 ◽  
Vol 21 (14) ◽  
pp. 5070
Author(s):  
Alejandro Lillo ◽  
Eva Martínez-Pinilla ◽  
Irene Reyes-Resina ◽  
Gemma Navarro ◽  
Rafael Franco
Keyword(s):  
Adenosine Receptor ◽  
Cortical Neurons ◽  
Resonance Energy Transfer ◽  
Physiological Role ◽  
Resonance Energy ◽  
Point Of View ◽  
The Novel ◽  
Differential Signaling ◽  
A2a Receptor ◽  
Adenosine A2a

The aim of this paper was to check the possible interaction of two of the four purinergic P1 receptors, the A2A and the A3. Discovery of the A2A–A3 receptor complex was achieved by means of immunocytochemistry and of bioluminescence resonance energy transfer. The functional properties and heteromer print identification were addressed by combining binding and signaling assays. The physiological role of the novel heteromer is to provide a differential signaling depending on the pre-coupling to signal transduction components and/or on the concentration of the endogenous agonist. The main feature was that the heteromeric context led to a marked decrease of the signaling originating at A3 receptors. Interestingly from a therapeutic point of view, A2A receptor antagonists overrode the blockade, thus allowing A3 receptor-mediated signaling. The A2A–A3 receptor heteromer print was detected in primary cortical neurons. These and previous results suggest that all four adenosine receptors may interact with each other. Therefore, each adenosine receptor could form heteromers with distinct properties, expanding the signaling outputs derived from the binding of adenosine to its cognate receptors.

scholarly journals PhenQE8, a Novel Ligand of the Human Telomeric Quadruplex

2021 ◽  
Vol 22 (2) ◽  
pp. 749
Author(s):  
Patricia B. Gratal ◽  
Julia G. Quero ◽  
Adrián Pérez-Redondo ◽  
Zoila Gándara ◽  
Lourdes Gude
Keyword(s):  
Equilibrium Dialysis ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
The Novel ◽  
X Ray Diffraction ◽  
Telomeric Dna ◽  
Healthy Human ◽  
Quadruplex Dna ◽  
Step Procedure ◽  
G Quadruplex

A novel quadruplex ligand based on 1,10-phenanthroline and incorporating two guanyl hydrazone functionalities, PhenQE8, is reported herein. Synthetic access was gained in a two-step procedure with an overall yield of 61%. X-ray diffraction studies revealed that PhenQE8 can adopt an extended conformation that may be optimal to favor recognition of quadruplex DNA. DNA interactions with polymorphic G-quadruplex telomeric structures were studied by different techniques, such as Fluorescence resonance energy transfer (FRET) DNA melting assays, circular dichroism and equilibrium dialysis. Our results reveal that the novel ligand PhenQE8 can efficiently recognize the hybrid quadruplex structures of the human telomeric DNA, with high binding affinity and quadruplex/duplex selectivity. Moreover, the compound shows significant cytotoxic activity against a selected panel of cultured tumor cells (PC-3, HeLa and MCF-7), whereas its cytotoxicity is considerably lower in healthy human cells (HFF-1 and RPWE-1).

scholarly journals Neuroprotection afforded by adenosine A2A receptor blockade is modulated by corticotrophin-releasing factor (CRF) in glutamate injured cortical neurons

2012 ◽  
Vol 123 (6) ◽  
pp. 1030-1040 ◽  
Author(s):  
Jorge S. Valadas ◽  
Vânia L. Batalha ◽  
Diana G. Ferreira ◽  
Rui Gomes ◽  
Joana E. Coelho ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Adenosine A2a Receptor ◽  
Receptor Blockade ◽  
Corticotrophin Releasing Factor ◽  
A2a Receptor ◽  
Adenosine A2a

Adenosine A2A receptor agonists and PDE inhibitors: a synergistic multitarget mechanism discovered through systematic combination screening in B-cell malignancies

Blood ◽  
2010 ◽  
Vol 116 (4) ◽  
pp. 593-602 ◽  
Author(s):  
Richard J. Rickles ◽  
Laura T. Pierce ◽  
Thomas P. Giordano ◽  
Winnie F. Tam ◽  
Douglas W. McMillin ◽  
...  
Keyword(s):  
B Cell ◽  
Adenosine Receptor ◽  
High Throughput Screening ◽  
B Cell Lymphoma ◽  
Adenosine A2a Receptor ◽  
Adenosine Receptor Agonists ◽  
Receptor Agonists ◽  
Pde Inhibitors ◽  
A2a Receptor ◽  
Adenosine A2a

Abstract Using a combination high-throughput screening technology, multiple classes of drugs and targeted agents were identified that synergize with dexamethasone (Dex) in multiple myeloma (MM) cells. Performing combination screening with these enhancers, we discovered an unexpected synergistic interaction between adenosine receptor agonists and phosphodiesterase (PDE) inhibitors that displays substantial activity in a panel of MM and diffuse large B-cell lymphoma (DLBCL) cell lines and tumor cells from MM patients. We have used selective adenosine receptor agonists, antagonists, and PDE inhibitors as well as small interfering RNAs targeting specific molecular isoforms of these proteins to dissect the molecular mechanism of this synergy. The adenosine A2A receptor and PDE2, 3, 4, and 7 are important for activity. Drug combinations induce cyclic AMP (cAMP) accumulation and up-regulate PDE4B. We also observe rigorous mathematical synergy in 3-way combinations containing A2A agonists, PDE inhibitors, and Dex at multiple concentrations and ratios. Taken together, these data suggest that A2A agonist/PDE inhibitor combinations may be attractive as an adjunctive to clinical glucocorticoid containing regiments for patients with MM or DLBCL and confer benefit in both glucocorticoid-sensitive and -resistant populations.

Activation of Adenosine A2A Receptor Up-Regulates BDNF Expression in Rat Primary Cortical Neurons

2011 ◽  
Vol 36 (12) ◽  
pp. 2259-2269 ◽  
Author(s):  
Se Jin Jeon ◽  
So Young Rhee ◽  
Jong Hoon Ryu ◽  
Jae Hoon Cheong ◽  
Kyungja Kwon ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Adenosine A2a Receptor ◽  
Bdnf Expression ◽  
Primary Cortical Neurons ◽  
A2a Receptor ◽  
Adenosine A2a

scholarly journals Diazepam Accelerates GABAAR Synaptic Exchange and Alters Intracellular Trafficking

2019 ◽  
Author(s):  
Joshua M. Lorenz-Guertin ◽  
Matthew J. Bambino ◽  
Sabyasachi Das ◽  
Susan T. Weintraub ◽  
Tija C. Jacob
Keyword(s):  
Cortical Neurons ◽  
Fluorescent Protein ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Adult Brain ◽  
Scaffolding Protein ◽  
Gamma Aminobutyric Acid ◽  
Inhibitory Neurotransmitter

Despite 50+ years of clinical use as anxiolytics, anti-convulsants, and sedative/hypnotic agents, the mechanisms underlying benzodiazepine (BZD) tolerance are poorly understood. BZDs potentiate the actions of gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the adult brain, through positive allosteric modulation of γ2 subunit containing GABA type A receptors (GABAARs). Here we define key molecular events impacting γ2 GABAAR and the inhibitory synapse gephyrin scaffold following initial sustained BZD exposure in vitro and in vivo. Using immunofluorescence and biochemical experiments, we found that cultured cortical neurons treated with the classical BZD, diazepam (DZP), presented no substantial change in surface or synaptic levels of γ2-GABAARs. In contrast, both γ2 and the postsynaptic scaffolding protein gephyrin showed diminished total protein levels following a single DZP treatment in vitro and in mouse cortical tissue. We further identified DZP treatment enhanced phosphorylation of gephyrin Ser270 and increased generation of gephyrin cleavage products. Selective immunoprecipitation of γ2 from cultured neurons revealed enhanced ubiquitination of this subunit following DZP exposure. To assess novel trafficking responses induced by DZP, we employed a γ2 subunit containing an N terminal fluorogen-activating peptide (FAP) and pH-sensitive green fluorescent protein (γ2pHFAP). Live-imaging experiments using γ2pHFAP GABAAR expressing neurons identified enhanced lysosomal targeting of surface GABAARs and increased overall accumulation in vesicular compartments in response to DZP. Using fluorescence resonance energy transfer (FRET) measurements between γ2 and γ2 subunits within a GABAAR in neurons, we identified reductions in synaptic clusters of this subpopulation of surface BZD sensitive receptor. Moreover, we found DZP simultaneously enhanced synaptic exchange of both γ2-GABAARs and gephyrin using fluorescence recovery after photobleaching (FRAP) techniques. Finally we provide the first proteomic analysis of the BZD sensitive GABAAR interactome in DZP vs. vehicle treated mice. Collectively, our results indicate DZP exposure elicits down-regulation of gephyrin scaffolding and BZD sensitive GABAAR synaptic availability via multiple dynamic trafficking processes.

scholarly journals Revisiting the Allosteric Regulation of Sodium Cation on the Binding of Adenosine at the Human A2A Adenosine Receptor: Insights from Supervised Molecular Dynamics (SuMD) Simulations

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2752 ◽  
Author(s):  
Maicol Bissaro ◽  
Giovanni Bolcato ◽  
Giuseppe Deganutti ◽  
Mattia Sturlese ◽  
Stefano Moro
Keyword(s):  
Molecular Dynamics ◽  
Sodium Cation ◽  
Point Of View ◽  
Sodium Ion ◽  
Transmembrane Helices ◽  
A2a Adenosine Receptor ◽  
Recognition Mechanism ◽  
A2a Receptor ◽  
Negative Allosteric Modulator ◽  
Adenosine A2a

One of the most intriguing findings highlighted from G protein-coupled receptor (GPCR) crystallography is the presence, in many members of class A, of a partially hydrated sodium ion in the middle of the seven transmembrane helices (7TM) bundle. In particular, the human adenosine A2A receptor (A2A AR) is the first GPCR in which a monovalent sodium ion was crystallized in a distal site from the canonical orthosteric one, corroborating, from a structural point of view, its role as a negative allosteric modulator. However, the molecular mechanism by which the sodium ion influences the recognition of the A2A AR agonists is not yet fully understood. In this study, the supervised molecular dynamics (SuMD) technique was exploited to analyse the sodium ion recognition mechanism and how its presence influences the binding of the endogenous agonist adenosine. Due to a higher degree of flexibility of the receptor extracellular (EC) vestibule, we propose the sodium-bound A2A AR as less efficient in stabilizing the adenosine during the different steps of binding.

N-Substituted Quinazolin- 2,4-diones as Adenosine Receptor Ligands

2010 ◽  
Vol 3 (2) ◽  
pp. 1015-1021
Author(s):  
Shireesha B ◽  
G.V. Kumar ◽  
V M Reddy ◽  
Raghuprasad M ◽  
A R Rao
Keyword(s):  
Receptor Binding ◽  
Adenosine Receptor ◽  
Antagonistic Activity ◽  
Mice Model ◽  
Receptor Ligands ◽  
Binding Studies ◽  
A2a Receptor ◽  
A1 Receptor ◽  
Adenosine Receptor Ligands ◽  
Adenosine A2a

Six new N-substituted quinazolinones were synthesized and evaluated for their adenosine antagonistic activity using allergic mice model where 1, 3-dibenzyl and 1, 3-dibutyl-quinazolindiones were found to be potent than 1, 3-dimethylanalogues. They were not significant in controlling the neutrophil and lymphocyte count but effective in controlling the eosinophil influx. In adenosine receptor binding studies, 1,3-dimethyl and 1,3-dibutyl derivatives were found to have significant adenosine A1 receptor binding efficiency with Ki values 9nM and 10nM, respectively, while 1,3- dibenzyl-quinazolinone was found to have significant binding to adenosine A2A receptor showing the influence of alkyl and aralkyl groups present in these compounds. Thus, the present work indicates the possibility to explore quinazolindiones as adenosine receptor ligands.

scholarly journals Precursor of Brain-derived Neurotrophic Factor (proBDNF) Forms a Complex with Huntingtin-associated Protein-1 (HAP1) and Sortilin That Modulates proBDNF Trafficking, Degradation, and Processing

2011 ◽  
Vol 286 (18) ◽  
pp. 16272-16284 ◽  
Author(s):  
Miao Yang ◽  
Yoon Lim ◽  
Xiaojiang Li ◽  
Jin-Hua Zhong ◽  
Xin-Fu Zhou
Keyword(s):  
Amino Acids ◽  
Neurotrophic Factor ◽  
Cortical Neurons ◽  
Molecular Motor ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Brain Derived Neurotrophic Factor ◽  
Hek293 Cells ◽  
Furin Cleavage ◽  
Cultured Cortical Neurons

proBDNF, a precursor of brain-derived neurotrophic factor (BDNF), is anterogradely transported and released from nerve terminals, but the mechanism underlying this process remains unclear. In this study, we report that proBDNF forms a complex with Huntingtin associated protein-1 (HAP1) and sortilin, which plays an important role in proBDNF intracellular trafficking and stabilization. The interaction of proBDNF with both HAP1A and sortilin in co-transfected HEK293 cells is confirmed by both fluorescence resonance energy transfer and co-immunoprecipitation. The frequent co-localization (>90%) of endogenous HAP1, sortilin, and proBDNF is also found in cultured cortical neurons. Mapping studies using GST pulldown and competition assays has defined the interacting region of HAP1 with proBDNF within amino acids 371–445 and the binding sequences of proBDNF to HAP1 between amino acids 65 and 90. Fluorescence recovery after photobleaching confirms the defective movement of proBDNF-containing vesicles in neurites of HAP1−/− neurons, which can be partially restored by reintroducing HAP1 cDNA into the neurons. However, the effect is significantly increased by simultaneously reintroducing both HAP1 and sortilin. proBDNF and HAP1 are highly co-localized with organelle markers for the Golgi network, microtubules, molecular motor, or endosomes in normal neurons, but this co-localization is reduced in HAP1−/− neurons. Co-immunoprecipitation and Western blot showed that sortilin stabilizes the proBDNF·HAP1 complex in co-transfected HEK293 cells, helping to prevent proBDNF degradation. Furthermore, the complex facilitates furin cleavage to release mature BDNF.

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