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Pharmacological Research Jan 2024The 5-hydroxytryptamine 7 receptor (5-HT) is necessary for 5-HT to cause a concentration-dependent vascular relaxation and hypotension. 5-HT is recognized as having...
The 5-hydroxytryptamine 7 receptor (5-HT) is necessary for 5-HT to cause a concentration-dependent vascular relaxation and hypotension. 5-HT is recognized as having biased signaling, transduced through either Gs or β -arrestin. It is unknown whether 5-HT signals in a biased manner to cause vasorelaxation/hypotension. We used the recently described β-arrestin selective 5-HT receptor agonist serodolin to test the hypothesis that 5-HT activation does not cause vascular relaxation or hypotension via the β -arrestin pathway. Isolated abdominal aorta (no functional 5-HT) and vena cava (functional 5-HT) from male Sprague Dawley rats were used in isometric contractility studies. Serodolin (1 nM - 10 μM) did not change baseline tone of isolated tissues and did not relax the endothelin-1 (ET-1)-contracted vena cava or aorta. In the aorta, serodolin acted as a 5-HT receptor antagonist, evidenced by a rightward shift in 5-HT-induced concentration response curve [pEC 5-HT [M]: Veh = 5.2 +/- 0.15; Ser (100 nM) = 4.49 +/- 0.08; p < 0.05]. In the vena cava, serodolin acted as a 5-HT receptor antagonist, shifting the concentration response curve to 5-HT left and upward (%10 μM NE contraction; Veh = 3.2 +/- 1.7; Ser (10 nM) = 58 +/- 11; p < 0.05) and blocking relaxation of pre-contracted tissue to the 5-HT agonist 5-carboxamidotryptamine. In anesthetized rats, 5-HT or serodolin was infused at 5, 25 and 75 μg/kg/min, iv. Though 5-HT caused concentration-dependent depressor responses, serodolin caused an insignificant small depressor responses at all three infusion rates. With the final dose of serodolin on board, 5-HT was unable to reduce blood pressure. Collectively the data indicate that serodolin functions as a 5-HT antagonist with additional 5-HT blocking properties. 5-HT activation does not cause vascular relaxation or hypotension via the β -arrestin pathway.
Topics: Rats; Animals; Male; Serotonin; Serotonin Receptor Agonists; beta-Arrestins; Rats, Sprague-Dawley; Hypotension
PubMed: 38157998
DOI: 10.1016/j.phrs.2023.107047 -
Journal of Medicinal Chemistry Jan 2024Orphan G-protein-coupled receptor 84 (GPR84) is a receptor that has been linked to cancer, inflammatory, and fibrotic diseases. We have reported DL-175 as a biased...
Orphan G-protein-coupled receptor 84 (GPR84) is a receptor that has been linked to cancer, inflammatory, and fibrotic diseases. We have reported DL-175 as a biased agonist at GPR84 which showed differential signaling via G/cAMP and β-arrestin, but which is rapidly metabolized. Herein, we describe an optimization of DL-175 through a systematic structure-activity relationship (SAR) analysis. This reveals that the replacement of the naphthalene group improved metabolic stability and the addition of a 5-hydroxy substituent to the pyridine -oxide group, yielding compounds (OX04528) and (OX04529), enhanced the potency for cAMP signaling by 3 orders of magnitude to low picomolar values. Neither compound showed detectable effects on β-arrestin recruitment up to 80 μM. Thus, the new GPR84 agonists and displayed excellent potency, high G-protein signaling bias, and an appropriate pharmacokinetic profile that will allow investigation of GPR84 biased agonist activity .
Topics: Receptors, G-Protein-Coupled; GTP-Binding Proteins; Signal Transduction; beta-Arrestins; Structure-Activity Relationship
PubMed: 38146625
DOI: 10.1021/acs.jmedchem.3c00951 -
Endocrinology, Diabetes & Metabolism Jan 2024Metformin (Met) and dexamethasone (Dexa) are known to reduce blood sugar levels and anti-inflammatory effects, respectively. Based on the acceleration of atherosclerosis...
BACKGROUND
Metformin (Met) and dexamethasone (Dexa) are known to reduce blood sugar levels and anti-inflammatory effects, respectively. Based on the acceleration of atherosclerosis process in diabetes, the β-arrestin 2 (BARR2) gene and protein expression levels were evaluated in vascular smooth muscle cells (VSMCs) treated with Met and Dexa in high glucose conditions in this study.
METHODS AND MATERIALS
Human VSMCs were cultured in Dulbecco's Modified Eagle Medium/Nutrient Mixture F-12 (DMEM-F12) medium and, were treated with different values of Met (1 mM, 5 mM and 7 mM) and Dexa (10 M, 10 M and 10 M) in 24- and 48-h periods. The BARR2 gene and protein expression levels were identified with RT-qPCR and western blotting techniques, respectively. The signalling axes were predicted from gene network made using Cytoscape software and, were annotated with Gene Ontology.
RESULTS
The BARR2 gene and protein expression levels reduced in VSMCs treated with Dexa and Met after 24- and 48-h periods. These results were more changed after 48 h. Furthermore, many BARR2-related signalling axes were found from the network genes.
CONCLUSION
Met and Dexa suppressed the BARR2 protein and gene expression levels in the VSMCs. Moreover, the gene network suggested some the cellular signalling axes related to BARR2 that may be affected by Met and Dexa.
Topics: Humans; Metformin; beta-Arrestins; Muscle, Smooth, Vascular; Glucose; Dexamethasone
PubMed: 38102782
DOI: 10.1002/edm2.465 -
Protein & Cell Feb 2024
Topics: beta-Arrestins; Receptor, Cannabinoid, CB1; Cryoelectron Microscopy
PubMed: 38102480
DOI: 10.1093/procel/pwad055 -
Nature Communications Dec 2023Serotonergic psychedelics possess considerable therapeutic potential. Although 5-HT receptor activation mediates psychedelic effects, prototypical psychedelics activate...
Serotonergic psychedelics possess considerable therapeutic potential. Although 5-HT receptor activation mediates psychedelic effects, prototypical psychedelics activate both 5-HT-Gq/11 and β-arrestin2 transducers, making their respective roles unclear. To elucidate this, we develop a series of 5-HT-selective ligands with varying Gq efficacies, including β-arrestin-biased ligands. We show that 5-HT-Gq but not 5-HT-β-arrestin2 recruitment efficacy predicts psychedelic potential, assessed using head-twitch response (HTR) magnitude in male mice. We further show that disrupting Gq-PLC signaling attenuates the HTR and a threshold level of Gq activation is required to induce psychedelic-like effects, consistent with the fact that certain 5-HT partial agonists (e.g., lisuride) are non-psychedelic. Understanding the role of 5-HT Gq-efficacy in psychedelic-like psychopharmacology permits rational development of non-psychedelic 5-HT agonists. We also demonstrate that β-arrestin-biased 5-HT receptor agonists block psychedelic effects and induce receptor downregulation and tachyphylaxis. Overall, 5-HT receptor Gq-signaling can be fine-tuned to generate ligands distinct from classical psychedelics.
Topics: Male; Animals; Mice; Hallucinogens; Receptor, Serotonin, 5-HT2A; Serotonin; Signal Transduction; beta-Arrestins; Ligands
PubMed: 38102107
DOI: 10.1038/s41467-023-44016-1 -
Cell Death and Differentiation Feb 2024Whole-genome screens using CRISPR technologies are powerful tools to identify novel tumour suppressors as well as factors that impact responses of malignant cells to...
Whole-genome screens using CRISPR technologies are powerful tools to identify novel tumour suppressors as well as factors that impact responses of malignant cells to anti-cancer agents. Applying this methodology to lymphoma cells, we conducted a genome-wide screen to identify novel inhibitors of tumour expansion that are induced by the tumour suppressor TRP53. We discovered that the absence of Arrestin domain containing 3 (ARRDC3) increases the survival and long-term competitiveness of MYC-driven lymphoma cells when treated with anti-cancer agents that activate TRP53. Deleting Arrdc3 in mice caused perinatal lethality due to various developmental abnormalities, including cardiac defects. Notably, the absence of ARRDC3 markedly accelerated MYC-driven lymphoma development. Thus, ARRDC3 is a new mediator of TRP53-mediated suppression of tumour expansion, and this discovery may open new avenues to harness this process for cancer therapy.
Topics: Animals; Mice; Arrestins; Clustered Regularly Interspaced Short Palindromic Repeats; Lymphoma; Neoplasms
PubMed: 38097622
DOI: 10.1038/s41418-023-01249-3 -
Advanced Science (Weinheim,... Feb 2024T-2 toxin causes renal dysfunction with proteinuria and glomerular podocyte damage. This work explores the role of metabolic disorder/reprogramming-mediated epigenetic...
T-2 toxin causes renal dysfunction with proteinuria and glomerular podocyte damage. This work explores the role of metabolic disorder/reprogramming-mediated epigenetic modification in the progression of T-2 toxin-stimulated podocyte injury. A metabolomics experiment is performed to assess metabolic responses to T-2 toxin infection in human podocytes. Roles of protein O-linked-N-acetylglucosaminylation (O-GlcNAcylation) in regulating T-2 toxin-stimulated podocyte injury in mouse and podocyte models are assessed. O-GlcNAc target proteins are recognized by mass spectrometry and co-immunoprecipitation experiments. Moreover, histone acetylation and autophagy levels are measured. T-2 toxin infection upregulates glucose transporter type 1 (GLUT1) expression and enhances hexosamine biosynthetic pathway in glomerular podocytes, resulting in a significant increase in β-arrestin-1 O-GlcNAcylation. Decreasing β-arrestin-1 or O-GlcNAc transferase (OGT) effectively prevents T-2 toxin-induced renal dysfunction and podocyte injury. Mechanistically, O-GlcNAcylation of β-arrestin-1 stabilizes β-arrestin-1 to activate the mammalian target of rapamycin (mTOR) pathway as well as to inhibit autophagy during podocyte injury by promoting H4K16 acetylation. To sum up, OGT-mediated β-arrestin-1 O-GlcNAcylation is a vital regulator in the development of T-2 toxin-stimulated podocyte injury via activating the mTOR pathway to suppress autophagy. Targeting β-arrestin-1 or OGT can be a potential therapy for T-2 toxin infection-associated glomerular injury, especially podocyte injury.
Topics: Mice; Humans; Animals; Acetylation; Histones; Podocytes; beta-Arrestin 1; T-2 Toxin; TOR Serine-Threonine Kinases; Kidney Diseases; Mammals
PubMed: 38083975
DOI: 10.1002/advs.202307648 -
Frontiers in Neurology 2023Dihydroergotamine mesylate (DHE) is an established effective acute therapy for migraine and is often characterized by its broad receptor pharmacology. Knowledge of DHE...
INTRODUCTION
Dihydroergotamine mesylate (DHE) is an established effective acute therapy for migraine and is often characterized by its broad receptor pharmacology. Knowledge of DHE pharmacology largely comes from studies employing older methodologies.
OBJECTIVE
To assess DHE receptor activity using high-throughput methods to screen for functional ß-arrestin activity at G protein-coupled receptors (GPCRs).
METHODS
Functional receptor activities of DHE and sumatriptan succinate (both 10 μM) were screened against 168 GPCRs using the gpcrMAX assay. Agonist and antagonist effects were considered significant if receptor activity was >30% or inhibited by >50%, respectively. Radiolabeled ligand binding assays were performed for DHE (0.01-300 nM for 5-HT and ; 0.3-10,000 nM for 5-HT, α-adrenergic [i.e., α-adrenoceptor], D, and D) to assess specific binding to select receptors.
RESULTS
DHE (10 μM) exhibited agonist activity at α-adrenergic, CXC chemokine receptor 7 (CXCR7), dopamine (D), and 5-hydroxytryptamine (5-HT) receptors and antagonist activity at α-adrenergic (i.e., α-adrenoceptors), calcitonin receptor-receptor activity modifying protein 2 (CTR-RAMP2) or amylin 2 (AMY), D, and 5-HT receptors. Sumatriptan succinate (10 μM) exhibited agonist activity at the 5-HT receptors. DHE demonstrated a half-maximal inhibitory concentration (IC) of 149 nM at the 5-HT receptor and a half-maximal effective concentration (EC) of 6 μM at the CXCR7 receptor. DHE did not bind to the 5-HT receptor at concentrations up to 300 nM and bound poorly to 5-HT and D receptors (IC of 230 and 370 nM, respectively). DHE bound strongly to the D, 5-HT, and α-adrenergic receptors (IC of 0.47, 0.58, and 2.8 nM, respectively).
CONCLUSION
By using a high-throughput β-arrestin recruitment assay, this study confirmed the broad receptor profile of DHE and provided an update on DHE receptor pharmacology as it relates to migraine.
PubMed: 38073648
DOI: 10.3389/fneur.2023.1282846 -
Functional profiling of the G protein-coupled receptor C3aR1 reveals ligand-mediated biased agonism.The Journal of Biological Chemistry Jan 2024G protein-coupled receptors (GPCRs) are leading druggable targets for several medicines, but many GPCRs are still untapped for their therapeutic potential due to poor...
G protein-coupled receptors (GPCRs) are leading druggable targets for several medicines, but many GPCRs are still untapped for their therapeutic potential due to poor understanding of specific signaling properties. The complement C3a receptor 1 (C3aR1) has been extensively studied for its physiological role in C3a-mediated anaphylaxis/inflammation, and in TLQP-21-mediated lipolysis, but direct evidence for the functional relevance of the C3a and TLQP-21 ligands and signal transduction mechanisms are still limited. In addition, C3aR1 G protein coupling specificity is still unclear, and whether endogenous ligands, or drug-like compounds, show ligand-mediated biased agonism is unknown. Here, we demonstrate that C3aR1 couples preferentially to Gi/o/z proteins and can recruit β-arrestins to cause internalization. Furthermore, we showed that in comparison to C3a, TLQP-21 exhibits a preference toward Gi/o-mediated signaling compared to β-arrestin recruitment and internalization. We also show that the purported antagonist SB290157 is a very potent C3aR1 agonist, where antagonism of ligand-stimulated C3aR1 calcium flux is caused by potent β-arrestin-mediated internalization. Finally, ligand-mediated signaling bias impacted cell function as demonstrated by the regulation of calcium influx, lipolysis in adipocytes, phagocytosis in microglia, and degranulation in mast cells. Overall, we characterize C3aR1 as a Gi/o/z-coupled receptor and demonstrate the functional relevance of ligand-mediated signaling bias in key cellular models. Due to C3aR1 and its endogenous ligands being implicated in inflammatory and metabolic diseases, these results are of relevance toward future C3aR1 drug discovery.
Topics: beta-Arrestin 1; beta-Arrestins; Calcium; Complement C3a; Ligands; Receptors, G-Protein-Coupled; Humans; Animals; Mice; Cell Line
PubMed: 38072064
DOI: 10.1016/j.jbc.2023.105549 -
Nutrients Dec 2023The edible fungus (ADe) is commonly employed in traditional medicine for intestinal disorders; however, its inhibitory effect on colitis-associated colorectal cancer...
BACKGROUND
The edible fungus (ADe) is commonly employed in traditional medicine for intestinal disorders; however, its inhibitory effect on colitis-associated colorectal cancer (CAC) and the underlying mechanisms remain unexplored. (2) Methods: The inhibitory effect of ADe on CAC was investigated using a mouse model induced by azoxymethane/dextran sulfate sodium.
RESULTS
ADe effectively suppressed the growth and number of intestinal tumors in mice. Intestinal microbiota analyses revealed that ADe treatment increased and while it decreased , , , and . ADe regulated the levels of 2'-deoxyridine, creatinine, 1-palmitoyl lysophosphatidylcholine, and choline in serum. Furthermore, the levels of these metabolites were associated with the abundance of and . ADe up-regulated the free fatty acid receptor 2 and β-Arrestin 2, inhibited the nuclear factor kappa B (NF-κB) pathway, and significantly attenuated the levels of inflammatory cytokines, thereby mitigating the inflammatory in CAC mice.
CONCLUSIONS
The protective effect of ADe in CAC mice is associated with the regulation of intestinal microbiota, which leads to the inhibition of NF-kB pathway and regulation of inflammation.
Topics: Animals; Mice; Colitis; Auricularia; Colitis-Associated Neoplasms; Gastrointestinal Microbiome; Inflammation; NF-kappa B; Dextran Sulfate; Mice, Inbred C57BL; Disease Models, Animal; Colon
PubMed: 38068869
DOI: 10.3390/nu15235011