A bio-inspired enantioselective small-molecule artificial receptor for β adrenergic agonists and antagonists and its application for enantioselective extraction

2016 ◽  
Vol 52 (85) ◽  
pp. 12582-12585 ◽  
Author(s):  
Ángel L. Fuentes de Arriba ◽  
Luis Simón ◽  
Omayra H. Rubio ◽  
Laura M. Monleón ◽  
Victoria Alcázar ◽  
...  
Keyword(s):  
Small Molecule ◽  
Adrenergic Receptor ◽  
Adrenergic Agonists ◽  
Enantioselective Extraction ◽  
Chiral Extraction ◽  
Artificial Receptor

An enantiomeric inhalation! Inspired by the β adrenergic receptor, a small-molecule artificial receptor allows the chiral extraction of broncho/vaso dilator drugs.

Inhibition of Glutamatergic Synaptic Input to Spinal Lamina IIo Neurons by Presynaptic α2-Adrenergic Receptors

2002 ◽  
Vol 87 (4) ◽  
pp. 1938-1947 ◽  
Author(s):  
Yu-Zhen Pan ◽  
De-Pei Li ◽  
Hui-Lin Pan
Keyword(s):  
Receptor Antagonist ◽  
Synaptic Input ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Dorsal Root ◽  
Primary Afferents ◽  
Noradrenergic System ◽  
Analgesic Action ◽  
Adrenergic Agonists ◽  
Excitatory Synaptic Input

Activation of spinal α2-adrenergic receptors by the descending noradrenergic system and α2-adrenergic agonists produces analgesia. However, the sites and mechanisms of the analgesic action of spinally administered α2-adrenergic receptor agonists such as clonidine are not fully known. The dorsal horn neurons in the outer zone of lamina II (lamina IIo) are important for processing nociceptive information from C-fiber primary afferents. In the present study, we tested a hypothesis that activation of presynaptic α2-adrenergic receptors by clonidine inhibits the excitatory synaptic input to lamina IIo neurons. Whole cell voltage-clamp recordings were performed on visualized lamina IIo neurons in the spinal cord slice of rats. The miniature excitatory postsynaptic currents (mEPSCs) were recorded in the presence of tetrodotoxin, bicuculline, and strychnine. The evoked EPSCs were obtained by electrical stimulation of the dorsal root entry zone or the attached dorsal root. Both mEPSCs and evoked EPSCs were abolished by application of 6-cyano-7-nitroquinoxaline-2,3-dione. Clonidine (10 μM) significantly decreased the frequency of mEPSCs from 5.8 ± 0.9 to 2.7 ± 0.6 Hz (means ± SE) without altering the amplitude and the decay time constant of mEPSCs in 25 of 27 lamina IIo neurons. Yohimbine (2 μM, an α2-adrenergic receptor antagonist), but not prazosin (2 μM, an α1-adrenergic receptor antagonist), blocked the inhibitory effect of clonidine on the mEPSCs. Clonidine (1–20 μM, n = 8) also significantly attenuated the peak amplitude of evoked EPSCs in a concentration-dependent manner. The effect of clonidine on evoked EPSCs was abolished in the presence of yohimbine ( n = 5). These data suggest that clonidine inhibits the excitatory synaptic input to lamina IIo neurons through activation of α2-adrenergic receptors located on the glutamatergic afferent terminals. Presynaptic inhibition of glutamate release from primary afferents onto lamina IIoneurons likely plays an important role in the analgesic action produced by activation of the descending noradrenergic system and α2-adrenergic agonists.

Guanabenz and Clonidine, α2-Adrenergic Receptor Agonists, Inhibit Choroidal Neovascularization

2021 ◽  
Vol 18 ◽  
Author(s):  
Miruto Tanaka ◽  
Yuki Inoue ◽  
Takahiko Imai ◽  
Norifumi Tanida ◽  
Koichi Takahashi ◽  
...  
Keyword(s):  
Choroidal Neovascularization ◽  
Adrenergic Receptor ◽  
Intraperitoneal Administration ◽  
Age Related Macular Degeneration ◽  
High Dose ◽  
Adrenergic Agonists ◽  
Continuous Administration ◽  
Cell Growth And Migration ◽  
Receptor Agonists ◽  
Age Related

Background: Neovascular age-related macular degeneration (AMD) with choroidal neovascularization (CNV) is a leading cause of blindness in elderly people. Anti-vascular endothelial growth factor (anti-VEGF)-drugs are used to treat AMD patients; however, some patients are resistant to these therapies. Objective: The purpose of this study was to investigate the anti-angiogenic effects of α2-adrenergic agonists, including guanabenz and clonidine. Methods: We evaluated the anti-angiogenic effects of α2-adrenergic agonists in human retinal microvascular endothelial cells (HRMECs). A proliferation assay was conducted, and the migration ratio was evaluated. In a laser-induced CNV model, guanabenz and clonidine were delivered via intraperitoneal injection or implantation of an osmotic pump device. Fourteen days following CNV induction, CNV lesion size and fundus fluorescein angiography (FFA) were evaluated. Results: Guanabenz and clonidine inhibited VEGF-induced retinal endothelial cell growth and migration. In the CNV model mice, CNV lesion sizes were reduced by intraperitoneal administration of guanabenz or clonidine. Data, including body weight, systolic blood pressure, and heart rate showed that guanabenz (0.5 and 2.0 mg/kg/day) had little effect on these parameters; conversely, a high dose of clonidine (1.0 mg/kg/day) did affect these parameters. Additionally, clonidine did not affect CNV size, but continuous administration of guanabenz attenuated both CNV size and leakage from neovessels. Conclusion: Our study suggests a key role for α2-adrenergic receptors during CNV formation. Therefore, we suggest that α2-adrenergic receptor agonists may represent novel therapeutic drugs for patients with neovascular AMD.

Abstract 469: Targeting Beta Adrenergic Receptor Resensitization Aids in Preservation of Receptor Function

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Elizabeth E Martellli ◽  
Yu Sun ◽  
John George ◽  
Maradumane L Mohan ◽  
Randall Starling ◽  
...  
Keyword(s):  
Heart Failure ◽  
Small Molecule ◽  
In Silico ◽  
Adrenergic Receptor ◽  
Human Heart ◽  
Receptor Function ◽  
Human Heart Failure ◽  
Pp2a Activity ◽  
Pi3k Activity ◽  
Underlying Mechanisms

Beta adrenergic receptor (βAR) down-regulation and desensitization are hallmarks of heart failure. Traditionally, it has been considered that increased desensitization mechanisms underlie βAR dysfunction in heart failure but it is not known whether resensitization of βARs is altered and is an integral contributor to heart failure. We have previously shown that resensitization is regulated by inhibition of PP2A by I2PP2A via PI3Kγ (Vasudevan et. al., 2011), the underlying mechanisms of I2PP2A binding to PP2A are not well understood. We used PyMOL software to find the binding interaction between PP2A and I2PP2A. Based on in silico predictions, we generated a mutant PP2A that when expressed would compete out I2PP2A and inhibit I2PP2A from binding to endogenous PP2A. Expression of PP2A mutant in β2AR expressing cells showed preservation of β2AR function following stimulation as measured by reduced β2AR phosphorylation, increased cAMP generation and increased phosphatase function. We also generated a small molecule from our in silico predictions that could target the interface of I2PP2A and PP2A binding to find that disruption of the PP2A/I2PP2A interaction underlies receptor function. We will use this small molecule to look at preservation of βAR function and amelioration of cardiac function. To test whether resensitization is altered in heart failure we used plasma membrane and endosomal fractions from non-failing and paired pre- and post-LVAD samples to show PI3K activity, PP2A activity, β2AR phosphorylation and adenylyl cyclase activity as a measure of recovery in βAR function. Our studies showed that endosomal fractions from human heart failure samples had elevated PI3K activity associated with reduced PP2A activity supporting the idea that βAR resensitization is inhibited in human heart failure samples. Since human heart failure samples have inhibited resensitization we tested the underlying mechanisms regulating βAR resensitization. Thus ongoing studies suggest that targeting the resensitization of βAR could provide beneficial cardiac remodeling in conditions of chronic mechanical overload and will be further discussed.

Abstract 183: Small Molecule Gβ? Inhibition Reduces Pathologic Activation of Cardiac Fibroblasts

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Joshua G Travers ◽  
Fadia A Kamal ◽  
Burns C Blaxall
Keyword(s):  
Cardiac Hypertrophy ◽  
Small Molecule ◽  
Adrenergic Receptor ◽  
Cellular Proliferation ◽  
Therapeutic Potential ◽  
Cardiac Fibroblasts ◽  
Akt Phosphorylation ◽  
Potential Therapeutic Role ◽  
Protease Activated Receptor 1 ◽  
Chronic Activation

Heart failure (HF) is a devastating disease characterized by cardiac hypertrophy, fibrosis and inflammation. Excess signaling through Gβγ subunits leads to chronic β-adrenergic receptor (β-AR) downregulation, mediated predominantly by GRK2 in complex with PI3Kγ. Our recent work has demonstrated the therapeutic potential of the small molecule Gβγ-GRK2 inhibitor Gallein in limiting HF progression. Chronic activation of cardiac fibroblasts (CF), critical yet underappreciated myocardial cells, is a key contributor to pathologic cardiac remodeling. We hypothesized that Gβγ-GRK2 inhibition may limit pathologic CF activation. CFs were stimulated with Isoproterenol (Iso, β-AR agonist), AngII, or vehicle (V), +/- Gβγ inhibition for 24hr. Gallein treatment attenuated the induction of αSMA expression, a marker of pathologic CF activation, and two inflammatory cytokines, IL-1β and IL-6 in response to these pathologic stimuli (Iso, AngII), as assessed by real time PCR. This data suggest that Gallein treatment may reduce pathologic CF activation. Iso stimulation also enhances the phosphorylation of Akt, a kinase downstream of PI3Kγ known to be involved in cellular proliferation. Gβγ inhibition mitigated this induction, decreasing Akt phosphorylation >60% in response to Iso. This phenomenon was also observed in failing human CFs, in which Gallein decreased Akt phosphorylation >70%. We have recently demonstrated that the protease-activated receptor 1 (PAR1), a GPCR we have implicated in cardiac hypertrophy, is transactivated via chronic β-AR stimulation by induction of MMP-13, a protease we have found to be elevated in HF. Recent data from our lab and others have demonstrated that PAR1 is the most abundantly expressed GPCR in CFs, and that its stimulation in CFs may be pathologic. Interestingly, Gβγ inhibition treatment reduced PAR1 cleavage and activation in response to chronic Iso. In summary, small molecule Gβγ inhibition appears to reduce pathologic CF activation. The reduction in β-AR-mediated PAR1 cleavage reveals an alternative role for Gβγ inhibition in preventing CF activation and proliferation. These data suggest a potential therapeutic role for small molecule Gβγ inhibition in limiting pathologic CF activation and cardiac hypertrophy.

scholarly journals Allosteric “beta-blocker” isolated from a DNA-encoded small molecule library

2017 ◽  
Vol 114 (7) ◽  
pp. 1708-1713 ◽  
Author(s):  
Seungkirl Ahn ◽  
Alem W. Kahsai ◽  
Biswaranjan Pani ◽  
Qin-Ting Wang ◽  
Shuai Zhao ◽  
...  
Keyword(s):  
Binding Site ◽  
G Protein ◽  
Small Molecule ◽  
Adrenergic Receptor ◽  
Camp Production ◽  
Small Molecule Library ◽  
Small Molecule Libraries ◽  
Negative Allosteric Modulator ◽  
G Protein Coupled ◽  
Small Molecule Ligand

The β2-adrenergic receptor (β2AR) has been a model system for understanding regulatory mechanisms of G-protein–coupled receptor (GPCR) actions and plays a significant role in cardiovascular and pulmonary diseases. Because all known β-adrenergic receptor drugs target the orthosteric binding site of the receptor, we set out to isolate allosteric ligands for this receptor by panning DNA-encoded small-molecule libraries comprising 190 million distinct compounds against purified human β2AR. Here, we report the discovery of a small-molecule negative allosteric modulator (antagonist), compound 15 [([4-((2S)-3-(((S)-3-(3-bromophenyl)-1-(methylamino)-1-oxopropan-2-yl)amino)-2-(2-cyclohexyl-2-phenylacetamido)-3-oxopropyl)benzamide], exhibiting a unique chemotype and low micromolar affinity for the β2AR. Binding of 15 to the receptor cooperatively enhances orthosteric inverse agonist binding while negatively modulating binding of orthosteric agonists. Studies with a specific antibody that binds to an intracellular region of the β2AR suggest that 15 binds in proximity to the G-protein binding site on the cytosolic surface of the β2AR. In cell-signaling studies, 15 inhibits cAMP production through the β2AR, but not that mediated by other Gs-coupled receptors. Compound 15 also similarly inhibits β-arrestin recruitment to the activated β2AR. This study presents an allosteric small-molecule ligand for the β2AR and introduces a broadly applicable method for screening DNA-encoded small-molecule libraries against purified GPCR targets. Importantly, such an approach could facilitate the discovery of GPCR drugs with tailored allosteric effects.

Characterization of β-Adrenergic Receptor Linked to Adenylate Cyclase in a Human Cancer Cell Line (COLO 16)

1978 ◽  
Vol 55 (1) ◽  
pp. 23-29
Author(s):  
T. J. Martin ◽  
S. R. Nahorski ◽  
N. H. Hunt ◽  
J. K. Dawborn ◽  
R. S. Loomes ◽  
...  
Keyword(s):  
Adenylate Cyclase ◽  
Cell Line ◽  
Cancer Cell ◽  
Adrenergic Receptor ◽  
Cell Membranes ◽  
Human Cancer ◽  
Specific Binding ◽  
Cancer Cell Line ◽  
Human Cancer Cell ◽  
Adrenergic Agonists

1. A human cancer cell line (COLO 16) derived originally from an epidermal squamous cell carcinoma was found to possess adenylate cyclase responsiveness to β-adrenergic agonists. 2. The adenylate cyclase response was characterized with respect to activation constants (KA) for various β-adrenergic agonists and inhibition constants (Ki) for antagonists. 3. Intact cells responded with dose-dependent increases in production of cyclic adenosine 3′:5′-monophosphate. 4. Properties of the β-adrenergic receptor were evaluated by using the specific binding of [3H]propranolol to cell membranes. Specific binding was saturable, with KD 5.79 nmol/l and binding sites 0.68 pmol/mg of protein. 5. Competition for binding to cell membranes was shown by β-adrenergic agonists and antagonists and was stereospecific. There was close agreement between the affinity of these various agents on adenylate cyclase and receptor binding. 6. It is likely that the β-adrenergic receptor-linked adenylate cyclase in COLO 16 cells represents persistence in a cancer cell line of a receptor present normally in epidermal cells.

Adrenergic agonists suppress the proliferation of microglia through β2-adrenergic receptor

1998 ◽  
Vol 242 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Hiroko Fujita ◽  
Junya Tanaka ◽  
Nobuji Maeda ◽  
Masahiro Sakanaka
Keyword(s):  
Adrenergic Receptor ◽  
Adrenergic Agonists ◽  
Β2 Adrenergic Receptor
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