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Proceedings of the National Academy of... Aug 2023Catecholamine-stimulated β-adrenergic receptor (βAR) signaling via the canonical G-adenylyl cyclase-cAMP-PKA pathway regulates numerous physiological functions,...
Catecholamine-stimulated β-adrenergic receptor (βAR) signaling via the canonical G-adenylyl cyclase-cAMP-PKA pathway regulates numerous physiological functions, including the therapeutic effects of exogenous β-agonists in the treatment of airway disease. βAR signaling is tightly regulated by GRKs and β-arrestins, which together promote βAR desensitization and internalization as well as downstream signaling, often antithetical to the canonical pathway. Thus, the ability to βAR signaling toward the G pathway while avoiding β-arrestin-mediated effects may provide a strategy to improve the functional consequences of βAR activation. Since attempts to develop G-biased agonists and allosteric modulators for the βAR have been largely unsuccessful, here we screened small molecule libraries for allosteric modulators that selectively inhibit β-arrestin recruitment to the receptor. This screen identified several compounds that met this profile, and, of these, a difluorophenyl quinazoline (DFPQ) derivative was found to be a selective negative allosteric modulator of β-arrestin recruitment to the βAR while having no effect on βAR coupling to G. DFPQ effectively inhibits agonist-promoted phosphorylation and internalization of the βAR and protects against the functional desensitization of β-agonist mediated regulation in cell and tissue models. The effects of DFPQ were also specific to the βAR with minimal effects on the βAR. Modeling, mutagenesis, and medicinal chemistry studies support DFPQ derivatives binding to an intracellular membrane-facing region of the βAR, including residues within transmembrane domains 3 and 4 and intracellular loop 2. DFPQ thus represents a class of biased allosteric modulators that targets an allosteric site of the βAR.
Topics: beta-Arrestins; Arrestin; Signal Transduction; beta-Arrestin 1; Receptors, Adrenergic; Receptors, Adrenergic, beta-2
PubMed: 37490535
DOI: 10.1073/pnas.2302668120 -
Cardiovascular Research Jul 2023The importance of autoantibodies (AABs) against adrenergic/muscarinic receptors in heart failure (HF) is not well-understood. We investigated the prevalence and...
AIMS
The importance of autoantibodies (AABs) against adrenergic/muscarinic receptors in heart failure (HF) is not well-understood. We investigated the prevalence and clinical/prognostic associations of four AABs recognizing the M2-muscarinic receptor or the β1-, β2-, or β3-adrenergic receptor in a large and well-characterized cohort of patients with HF.
METHODS AND RESULTS
Serum samples from 2256 patients with HF from the BIOSTAT-CHF cohort and 299 healthy controls were analysed using newly established chemiluminescence immunoassays. The primary outcome was a composite of all-cause mortality and HF rehospitalization at 2-year follow-up, and each outcome was also separately investigated. Collectively, 382 (16.9%) patients and 37 (12.4%) controls were seropositive for ≥1 AAB (P = 0.045). Seropositivity occurred more frequently only for anti-M2 AABs (P = 0.025). Amongst patients with HF, seropositivity was associated with the presence of comorbidities (renal disease, chronic obstructive pulmonary disease, stroke, and atrial fibrillation) and with medication use. Only anti-β1 AAB seropositivity was associated with the primary outcome [hazard ratio (95% confidence interval): 1.37 (1.04-1.81), P = 0.024] and HF rehospitalization [1.57 (1.13-2.19), P = 0.010] in univariable analyses but remained associated only with HF rehospitalization after multivariable adjustment for the BIOSTAT-CHF risk model [1.47 (1.05-2.07), P = 0.030]. Principal component analyses showed considerable overlap in B-lymphocyte activity between seropositive and seronegative patients, based on 31 circulating biomarkers related to B-lymphocyte function.
CONCLUSIONS
AAB seropositivity was not strongly associated with adverse outcomes in HF and was mostly related to the presence of comorbidities and medication use. Only anti-β1 AABs were independently associated with HF rehospitalization. The exact clinical value of AABs remains to be elucidated.
Topics: Humans; Prognosis; Autoantibodies; Heart Failure; Receptors, Muscarinic; Receptor, Muscarinic M2; Receptors, Adrenergic
PubMed: 36883593
DOI: 10.1093/cvr/cvad042 -
Thyroid : Official Journal of the... Oct 2023Thyroid hormone (TH) has actions in every tissue of the body and is essential for normal development, as well as having important actions in the adult. The earliest...
Thyroid hormone (TH) has actions in every tissue of the body and is essential for normal development, as well as having important actions in the adult. The earliest markers of TH action that were identified and monitored clinically, even before TH could be measured in serum, included oxygen consumption, basal metabolic rate, serum cholesterol, and deep tendon reflex time. Cellular, rodent, amphibian, zebrafish, and human models have been used to study TH action. Early studies of the mechanism of TH action focused on saturable-specific triiodothyronine (T3) nuclear binding and direct actions of T3 that altered protein expression. Additional effects of TH were recognized on mitochondria, stimulation of ion transport, especially the sodium potassium ATPase, augmentation of adrenergic signaling, role as a neurotransmitter, and direct plasma membrane effects. The cloning of the thyroid hormone receptor (THR) genes in 1986 and report of the THR crystal structure in 1995 produced rapid progress in understanding the mechanism of TH nuclear action, as well as the development of modified THR ligands. These findings revealed nuances of TH signaling, including the role of nuclear receptor coactivators and corepressors, repression of positively stimulated genes by the unliganded receptor, THR isoform-specific actions of TRα (THRA) and TRβ (THRB), and THR binding DNA as a heterodimer with retinoid-x-receptor (RXR) for genes positively regulated by TH. The identification of genetic disorders of TH transport and signaling, especially Resistance to Thyroid Hormone (RTH) and monocarboxylate transporter 8 () defects, has been highly informative with respect to the mechanism of TH action. The impact of THR isoform, post-translational modifications, receptor cofactors, DNA response element, and selective TH tissue uptake, on TH action, have clinical implications for diagnosing and treating thyroid disease. Additionally, these findings have led to the development of novel TH and TH analogue therapies for metabolic, neurological, and cardiovascular diseases.
Topics: Animals; Adult; Humans; Zebrafish; Thyroid Hormone Receptors beta; Thyroid Hormones; Triiodothyronine; DNA; Protein Isoforms; Receptors, Thyroid Hormone
PubMed: 37594753
DOI: 10.1089/thy.2022.0636 -
Journal of Hypertension Nov 2023Maternal cardiovascular diseases, including hypertension and cardiac conditions, are associated with poor fetal outcomes. A range of adrenergic antihypertensive and... (Review)
Review
Maternal cardiovascular diseases, including hypertension and cardiac conditions, are associated with poor fetal outcomes. A range of adrenergic antihypertensive and cardioprotective medications are often prescribed to pregnant women to reduce major maternal complications during pregnancy. Although these treatments are not considered teratogenic, they may have detrimental effects on fetal growth and development, as they cross the fetoplacental barrier, and may contribute to placental vascular dysregulation. Medication risk assessment sheets do not include specific advice to clinicians and women regarding the safety of these therapies for use in pregnancy and the potential off-target effects of adrenergic medications on fetal growth have not been rigorously conducted. Little is known of their effects on the fetoplacental vasculature. There is also a dearth of knowledge on adrenergic receptor activation and signalling within the endothelium and vascular smooth muscle cells of the human placenta, a vital organ in the maintenance of adequate blood flow to satisfy fetal growth and development. The fetoplacental circulation, absent of sympathetic innervation, and unique in its reliance on endocrine, paracrine and autocrine influence in the regulation of vascular tone, appears vulnerable to dysregulation by adrenergic antihypertensive and cardioprotective medications compared with the adult peripheral circulation. This semi-systematic review focuses on fetoplacental vascular expression of adrenergic receptors, associated cell signalling mechanisms and predictive consequences of receptor activation/deactivation by antihypertensive and cardioprotective medications.
Topics: Adult; Female; Humans; Pregnancy; Adrenergic Agents; Antihypertensive Agents; Fetus; Placenta; Placental Circulation
PubMed: 37694528
DOI: 10.1097/HJH.0000000000003532 -
Circulation Research Nov 2023βAR (beta-1 adrenergic receptor) and βAR (beta-2 adrenergic receptor)-mediated cyclic adenosine monophosphate signaling has distinct effects on cardiac function and...
BACKGROUND
βAR (beta-1 adrenergic receptor) and βAR (beta-2 adrenergic receptor)-mediated cyclic adenosine monophosphate signaling has distinct effects on cardiac function and heart failure progression. However, the mechanism regulating spatial localization and functional compartmentation of cardiac β-ARs remains elusive. Emerging evidence suggests that microtubule-dependent trafficking of mRNP (messenger ribonucleoprotein) and localized protein translation modulates protein compartmentation in cardiomyocytes. We hypothesized that β-AR compartmentation in cardiomyocytes is accomplished by selective trafficking of its mRNAs and localized translation.
METHODS
The localization pattern of β-AR mRNA was investigated using single molecule fluorescence in situ hybridization and subcellular nanobiopsy in rat cardiomyocytes. The role of microtubule on β-AR mRNA localization was studied using vinblastine, and its effect on receptor localization and function was evaluated with immunofluorescent and high-throughput Förster resonance energy transfer microscopy. An mRNA protein co-detection assay identified plausible β-AR translation sites in cardiomyocytes. The mechanism by which β-AR mRNA is redistributed post-heart failure was elucidated by single molecule fluorescence in situ hybridization, nanobiopsy, and high-throughput Förster resonance energy transfer microscopy on 16 weeks post-myocardial infarction and detubulated cardiomyocytes.
RESULTS
βAR and βAR mRNAs show differential localization in cardiomyocytes, with βAR found in the perinuclear region and βAR showing diffuse distribution throughout the cell. Disruption of microtubules induces a shift of βAR transcripts toward the perinuclear region. The close proximity between βAR transcripts and translated proteins suggests that the translation process occurs in specialized, precisely defined cellular compartments. Redistribution of βAR transcripts is microtubule-dependent, as microtubule depolymerization markedly reduces the number of functional receptors on the membrane. In failing hearts, both βAR and βAR mRNAs are redistributed toward the cell periphery, similar to what is seen in cardiomyocytes undergoing drug-induced detubulation. This suggests that t-tubule remodeling contributes to β-AR mRNA redistribution and impaired βAR function in failing hearts.
CONCLUSIONS
Asymmetrical microtubule-dependent trafficking dictates differential βAR and βAR localization in healthy cardiomyocyte microtubules, underlying the distinctive compartmentation of the 2 β-ARs on the plasma membrane. The localization pattern is altered post-myocardial infarction, resulting from transverse tubule remodeling, leading to distorted βAR-mediated cyclic adenosine monophosphate signaling.
Topics: Rats; Animals; In Situ Hybridization, Fluorescence; Heart Failure; Receptors, Adrenergic, beta-2; Myocardial Infarction; Myocytes, Cardiac; Cyclic AMP; Receptors, Adrenergic, beta-1; Microtubules; RNA, Messenger; Adenosine Monophosphate
PubMed: 37869877
DOI: 10.1161/CIRCRESAHA.123.323174 -
Cancer Research Aug 2023Neuroblastoma (NB) is an aggressive childhood tumor, with high-risk cases having a 5-year overall survival probability of approximately 50%. The multimodal therapeutic...
UNLABELLED
Neuroblastoma (NB) is an aggressive childhood tumor, with high-risk cases having a 5-year overall survival probability of approximately 50%. The multimodal therapeutic approach for NB includes treatment with the retinoid isotretinoin (13-cis retinoic acid; 13cRA), which is used in the post-consolidation phase as an antiproliferation and prodifferentiation agent to minimize residual disease and prevent relapse. Through small-molecule screening, we identified isorhamnetin (ISR) as a synergistic compound with 13cRA in inhibiting up to 80% of NB cell viability. The synergistic effect was accompanied by a marked increase in the expression of the adrenergic receptor α1B (ADRA1B) gene. Genetic knockout of ADRA1B or its specific blockade using α1/α1B adrenergic antagonists led to selective sensitization of MYCN-amplified NB cells to cell viability reduction and neural differentiation induced by 13cRA, thus mimicking ISR activity. Administration of doxazosin, a safe α1-antagonist used in pediatric patients, in combination with 13cRA in NB xenografted mice exerted marked control of tumor growth, whereas each drug alone was ineffective. Overall, this study identified the α1B adrenergic receptor as a pharmacologic target in NB, supporting the evaluation of adding α1-antagonists to the post-consolidation therapy of NB to more efficiently control residual disease.
SIGNIFICANCE
Targeting α-adrenergic receptors synergizes with isotretinoin to suppress growth and to promote differentiation of neuroblastoma, revealing a combinatorial approach for more effective management of the disease and prevention of relapse.
Topics: Humans; Mice; Child; Animals; Isotretinoin; Adrenergic alpha-1 Receptor Antagonists; Cell Line, Tumor; Neoplasm Recurrence, Local; Neuroblastoma; Cell Differentiation; Receptors, Adrenergic; Recurrence; N-Myc Proto-Oncogene Protein
PubMed: 37289021
DOI: 10.1158/0008-5472.CAN-22-1913 -
European Journal of Histochemistry : EJH Aug 2023Lots of adrenergic receptors (ARs) are widely present across the auditory pathways and are positioned to affect auditory and vestibular functions. However, noradrenergic...
Lots of adrenergic receptors (ARs) are widely present across the auditory pathways and are positioned to affect auditory and vestibular functions. However, noradrenergic regulation in the cochlea has not been well characterized. In this study, a rat model of noise-induced hearing loss was developed to investigate the expression of α2A-adrenergic receptor (AR) after acoustic trauma, then, we investigated the expression of α2A-AR in the developing rat cochlea using immunofluorescence, qRT-PCR, and Western blotting. We found that the expression of α2A-AR significantly increased in rats exposed to noise compared with controls. Immunofluorescence analysis demonstrated that α2A-AR is localized on hair cells (HCs), spiral ganglion neurons (SGNs), and the stria vascularis (SV) in the postnatal developing cochlea from post-natal day (P) 0 to P28. Furthermore, we observed α2A-AR mRNA reached a maximum level at P14 and P28 when compared with P0, while no significant differences in α2A-AR protein levels at the various stages when compared with P0. This study provides direct evidence for the expression of α2A-AR in HCs, SGNs, and the SV of the cochlea, indicating that norepinephrine might play a vital role in hearing function within the cochlea through α2A-AR.
Topics: Animals; Rats; Cochlea; Norepinephrine; Rats, Sprague-Dawley; Spiral Ganglion; Receptors, Adrenergic, alpha-2
PubMed: 37548252
DOI: 10.4081/ejh.2023.3748 -
Georgian Medical News Sep 2023The aim of this study was to evaluate current approaches to the pharmacotherapy of posttraumatic stress disorder. An information search was carried out in the databases...
The aim of this study was to evaluate current approaches to the pharmacotherapy of posttraumatic stress disorder. An information search was carried out in the databases PubMed, Ovid, EMBASE by keywords: "posttraumatic stress disorder", "treatment", and "medications". Search depth 2012-2022 years. From the general data (4877 articles) there were selected 14 articles with the highest degree of relevance. A content analysis of selected articles was carried out with the formation of recommendations for the use of pharmacotherapy in posttraumatic stress disorder. Currently, there are no unified approaches to the pharmacotherapy of posttraumatic stress disorder. Antidepressants (SSRI SNRIs) are primarily considered as first-line drugs, but only sertraline, paroxetine, and fluoxetine are approved by the FDA. But these drugs have a fairly wide range of side effects, including suicidal thoughts. The use of benzodiazepines should be limited as they increase the risk of developing posttraumatic stress disorder. Vortioxetine becomes a very promising option. The most significant benefits of vortioxetine are the significant positive effects of vortioxetine on attention, memory, and executive function. There is some evidence for the use of alpha-1 adrenoceptor antagonists and alpha-2 adrenoceptor agonists in therapy. In insomnia the use of prazosin and trazodone is recommended. Pharmacotherapy of posttraumatic stress disorder requires administration of medications with multimodal action. Currently, there are no unified approaches to the pharmacotherapy of posttraumatic stress disorder. Further randomized clinical trials are necessary for developing effective treatment of posttraumatic stress disorder.
Topics: Humans; Antidepressive Agents; Receptors, Adrenergic; Stress Disorders, Post-Traumatic; Vortioxetine
PubMed: 37991966
DOI: No ID Found -
BioRxiv : the Preprint Server For... Feb 2024Beta-adrenergic receptors (βARs) are G protein-coupled receptors (GPCRs) that mediate catecholamine-induced stress responses, such as heart rate increase and...
Beta-adrenergic receptors (βARs) are G protein-coupled receptors (GPCRs) that mediate catecholamine-induced stress responses, such as heart rate increase and bronchodilation. In addition to signals from the cell surface, βARs also broadcast non-canonical signaling activities from the cell interior membranes (endomembranes). Dysregulation of these receptor pathways underlies severe pathological conditions. Excessive βAR stimulation is linked to cardiac hypertrophy, leading to heart failure, while impaired stimulation causes compromised fight or flight stress responses and homeostasis. In addition to plasma membrane βAR, emerging evidence indicates potential pathological implications of deeper endomembrane βARs, such as inducing cardiomyocyte hypertrophy and apoptosis, underlying heart failure. However, the lack of approaches to control their signaling in subcellular compartments exclusively has impeded linking endomembrane βAR signaling with pathology. Informed by the β1AR-catecholamine interactions, we engineered an efficiently photo-labile, protected hydroxy β1AR pro-ligand (OptoIso) to trigger βAR signaling at the cell surface, as well as exclusive endomembrane regions upon blue light stimulation. Not only does OptoIso undergo blue light deprotection in seconds, but it also efficiently enters cells and allows examination of G protein heterotrimer activation exclusively at endomembranes. In addition to its application in the optical interrogation of βARs in unmodified cells, given its ability to control deep organelle βAR signaling, OptoIso will be a valuable experimental tool.
PubMed: 38405895
DOI: 10.1101/2024.02.14.580335 -
Nature Communications Aug 2023α-adrenergic receptors (α-ARs) play critical roles in the cardiovascular and nervous systems where they regulate blood pressure, cognition, and metabolism. However,...
α-adrenergic receptors (α-ARs) play critical roles in the cardiovascular and nervous systems where they regulate blood pressure, cognition, and metabolism. However, the lack of specific agonists for all α subtypes has limited our understanding of the physiological roles of different α-AR subtypes, and led to the stagnancy in agonist-based drug development for these receptors. Here we report cryo-EM structures of α-AR in complex with heterotrimeric G-proteins and either the endogenous common agonist epinephrine or the α-AR-specific synthetic agonist A61603. These structures provide molecular insights into the mechanisms underlying the discrimination between α-AR and α-AR by A61603. Guided by the structures and corresponding molecular dynamics simulations, we engineer α-AR mutants that are not responsive to A61603, and α-AR mutants that can be potently activated by A61603. Together, these findings advance our understanding of the agonist specificity for α-ARs at the molecular level, opening the possibility of rational design of subtype-specific agonists.
Topics: Receptors, Adrenergic, alpha-1; Epinephrine; Signal Transduction
PubMed: 37563160
DOI: 10.1038/s41467-023-40524-2