The beta-adrenoceptor

The β2 adrenergic receptor cross-linked interactome identifies 14-3-3 proteins as regulating the availability of signaling-competent receptors

The emerging picture of G protein-coupled receptor function suggests that the global signaling response is an integrated sum of a multitude of individual receptor responses, each regulated by their local protein environment. The β2 adrenergic receptor (B2AR) has long served as an example receptor in the development of this model. However, the mechanism and the identity of the protein-protein interactions that govern the availability of receptors competent for signaling remain incompletely characterized. To address this question, we characterized the interactome of agonist-stimulated B2AR in human embryonic kidney 293 cells using FLAG coimmunoprecipitation coupled to stable isotope labeling by amino acids in cell culture and mass spectrometry. Our B2AR cross-linked interactome identified 190 high-confidence proteins, including almost all known interacting proteins and 6 out of 7 isoforms of the 14-3-3 family of scaffolding proteins. Inhibiting 14-3-3 proteins with the peptide difopein enhanced isoproterenol-stimulated adrenergic signaling via cAMP approximately 3-fold and increased both miniGs and arrestin recruitment to B2AR more than 2-fold each, without noticeably changing EC50 with respect to cAMP signaling or effector recruitment upon stimulation. Our results show that 14-3-3 proteins negatively regulate downstream signaling by inhibiting access of B2AR to effector proteins. We propose that 14-3-3 proteins maintain a dynamic pool of B2AR that has reduced signaling efficacy in response to acute agonist stimulation, limiting the number of signaling-competent receptors at the plasma membrane. SIGNIFICANCE STATEMENT: This study presents a new interactome of the agonist-stimulated β2 adrenergic receptor, a paradigmatic G protein-coupled receptor that is both a model system for members of this class and an important signaling protein in respiratory, cardiovascular, and metabolic regulation. We identify 14-3-3 proteins as responsible for restricting β2 adrenergic receptor access to signaling effectors and maintaining a receptor population that is insensitive to acute stimulation by agonists.

Update on the Role of β2AR and TRPV1 in Respiratory Diseases

Respiratory diseases (RDs) constitute a common public health problem both in industrialized and developing countries. The comprehension of the pathophysiological mechanisms underlying these conditions and the development of new therapeutic strategies are critical for improving the quality of life of affected patients. β2-adrenergic receptor (β2AR) and transient receptor potential vanilloid 1 (TRPV1) are both involved in physiological responses in the airways. β2AR is implicated in bronchodilation, mucociliary clearance, and anti-inflammatory effects, while TRPV1 is involved in the mediation of pain and cough reflexes. In RDs, such as respiratory infections, asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis, the concentration and expression of these receptors can be altered, leading to significant consequences. In this review, we provided an update on the literature about the role of β2AR and TRPV1 in these conditions. We reported how the diminished or defective expression of β2AR during viral infections or prolonged therapy with β2-agonists can increase the severity of these pathologies and impact the prognosis. Conversely, the role of TRPV1 was pivotal in neuroinflammation, and its modulation could lead to innovative treatment strategies in specific patients. We indicate future perspectives and potential personalized treatments in RDs through a comprehensive analysis of the roles of these receptors in the physiological and pathological mechanisms of these pathologies.

Beta-Blockers as an Immunologic and Autonomic Manipulator in Critically Ill Patients: A Review of the Recent Literature

The autonomic nervous system plays a key role in maintaining body hemostasis through both the sympathetic and parasympathetic nervous systems. Sympathetic overstimulation as a reflex to multiple pathologies, such as septic shock, brain injury, cardiogenic shock, and cardiac arrest, could be harmful and lead to autonomic and immunologic dysfunction. The continuous stimulation of the beta receptors on immune cells has an inhibitory effect on these cells and may lead to immunologic dysfunction through enhancing the production of anti-inflammatory cytokines, such as interleukin-10 (IL-10), and inhibiting the production of pro-inflammatory factors, such as interleukin-1B IL-1B and tissue necrotizing factor-alpha (TNF-alpha). Sympathetic overstimulation-induced autonomic dysfunction may also happen due to adrenergic receptor insensitivity or downregulation. Administering anti-adrenergic medication, such as beta-blockers, is a promising treatment to compensate against the undesired effects of adrenergic surge. Despite many misconceptions about beta-blockers, beta-blockers have shown a promising effect in decreasing mortality in patients with critical illness. In this review, we summarize the recently published articles that have discussed using beta-blockers as a promising treatment to decrease mortality in critically ill patients, such as patients with septic shock, traumatic brain injury, cardiogenic shock, acute decompensated heart failure, and electrical storm. We also discuss the potential pathophysiology of beta-blockers in various types of critical illness. More clinical trials are encouraged to evaluate the safety and effectiveness of beta-blockers in improving mortality among critically ill patients.

An overview of the efficacy and safety of β2-adrenoceptor antagonists for the treatment of chronic obstructive pulmonary disease

INTRODUCTION

The safety of β2-AR antagonists in the treatment of patients with COPD continues to be a topic of research and discussion within the medical community. Emerging evidence suggests potentially benefits in the management of this complex respiratory condition. However, antagonists that display a preference for β2-AR over β1-AR present a complex therapeutic challenge in COPD management, necessitating an understanding of differences in their pharmacological profiles and clinical implications.

AREAS COVERED

An overview of the mechanisms of action of β2-AR antagonists and their potential impact on respiratory function, their pharmacological interactions, clinical implications, and future perspectives in COPD.

EXPERT OPINION

β-Blockers have the potential to become a versatile class of therapeutic agents with benefits beyond their original cardiovascular use. However, the one-size-fits-all approach of prescribing β-blockers regardless of their receptor selectivity to COPD patients with concomitant heart disease may not be appropriate. Instead, it is advisable to develop an individualized treatment strategy based on a thorough assessment of the patient's overall health. The use of non selective β2-AR antagonists, functioning as inverse agonists at β2-ARs, has garnered interest and debate, but further research efforts should focus on elucidating the optimal use of β-AR antagonists in COPD, balancing cardiovascular benefits with potential respiratory risks to enhance outcomes and quality of life for individuals living with this debilitating respiratory condition.

Effects of chronic stress on cancer development and the therapeutic prospects of adrenergic signaling regulation

Long-term chronic stress is an important factor in the poor prognosis of cancer patients. Chronic stress reduces the tissue infiltration of immune cells in the tumor microenvironment (TME) by continuously activating the adrenergic signaling, inhibits antitumor immune response and tumor cell apoptosis while also inducing epithelial-mesenchymal transition (EMT) and tumor angiogenesis, promoting tumor invasion and metastasis. This review first summarizes how adrenergic signaling activates intracellular signaling by binding different adrenergic receptor (AR) heterodimers. Then, we focused on reviewing adrenergic signaling to regulate multiple functions of immune cells, including cell differentiation, migration, and cytokine secretion. In addition, the article discusses the mechanisms by which adrenergic signaling exerts pro-tumorigenic effects by acting directly on the tumor itself. It also highlights the use of adrenergic receptor modulators in cancer therapy, with particular emphasis on their potential role in immunotherapy. Finally, the article reviews the beneficial effects of stress intervention measures on cancer treatment. We think that enhancing the body's antitumor response by adjusting adrenergic signaling can enhance the efficacy of cancer treatment.

The Wiser Strategy of Using Beta-Agonists in Asthma: Mechanisms and Rationales

Concerns regarding the safety of beta-2 agonists have led to revisions of the major asthma guidelines to better address these issues. Although these updates allow for a combination of previous and current strategies, they may confuse clinical practitioners. Beta-2 agonists are vital for alleviating asthma symptoms by relaxing smooth muscles; however, they also pose significant risks by inducing pro-inflammatory mediators both in vitro and in vivo. In addition to the risks of overuse and symptom masking, the use of beta-agonists alone at therapeutic doses can worsen airway inflammation and enhance virus-induced inflammation during asthma exacerbation. Inhaled corticosteroids (ICS) can effectively prevent these adverse effects. With new insights into the mechanisms of these adverse events, reserving short-acting beta-agonists for acute symptom relief during exacerbations and only for those who are already on ICS or oral steroids represents a careful approach to using beta-agonists with least adverse effects in patients with asthma. However, a major drawback of this approach is the potential non-compliance with ICS, leading to beta-agonist use without the necessary counteraction by ICS. An optimal strategy, both during and outside exacerbations, would integrate beta-agonists into an anti-inflammatory regimen that includes ICS, ideally combined with the same inhaler to ensure their concurrent use where finances allow. This would maintain the beneficial effects of beta-agonists, such as bronchodilation, while preventing the adverse effects from the induction of inflammatory mediators. This method is aligned with diverse clinical settings, maximizes the safe use of beta-agonists, and supports a comprehensive guideline-compliant management strategy.

Medium-Dose Formoterol Attenuated Abdominal Aortic Aneurysm Induced by EPO via β2AR/cAMP/SIRT1 Pathway

Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease but effective drugs for treatment of AAA are still lacking. Recently, erythropoietin (EPO) is reported to induce AAA formation in apolipoprotein-E knock out (ApoE-/-) mice but an effective antagonist is unknown. In this study, formoterol, a β2 adrenergic receptor (β2AR) agonist, is found to be a promising agent for inhibiting AAA. To test this hypothesis, ApoE-/- mice are treated with vehicle, EPO, and EPO plus low-, medium-, and high-dose formoterol, respectively. The incidence of AAA is 0, 55%, 35%,10%, and 55% in these 5 groups, respectively. Mechanistically, senescence of vascular smooth muscle cell (VSMC) is increased by EPO while decreased by medium-dose formoterol both in vivo and in vitro, manifested by the altered expression of senescence biomarkers including phosphorylation of H2AXserine139, senescence-associated β-galactosidase activity, and P21 protein level. In addition, expression of sirtuin 1 (SIRT1) in aorta is decreased in EPO-induced AAA but remarkably elevated by medium-dose formoterol. Knockdown of β2AR and blockage of cyclic adenosine monophosphate (cAMP) attenuate the inhibitory role of formoterol in EPO-induced VSMC senescence. In summary, medium-dose formoterol attenuates EPO-induced AAA via β2AR/cAMP/SIRT1 pathways, which provides a promising medication for the treatment of AAA.

Advances in sarcopenia: mechanisms, therapeutic targets, and intervention strategies

Sarcopenia is a multifactorial condition characterized by loss of muscle mass. It poses significant health risks in older adults worldwide. Both pharmacological and non-pharmacological approaches are reported to address this disease. Certain dietary patterns, such as adequate energy intake and essential amino acids, have shown positive outcomes in preserving muscle function. Various medications, including myostatin inhibitors, growth hormones, and activin type II receptor inhibitors, have been evaluated for their effectiveness in managing sarcopenia. However, it is important to consider the variable efficacy and potential side effects associated with these treatments. There are currently no drugs approved by the Food and Drug Administration for sarcopenia. The ongoing research aims to develop more effective strategies in the future. Our review of research on disease mechanisms and drug development will be a valuable contribution to future research endeavors.

Acute Effects of Albuterol on Ventilatory Capacity in Children with Asthma

BACKGROUND

Children with asthma may have a reduced ventilatory capacity, which could lead to symptoms and early termination of a cardiopulmonary exercise test (CPET). The purpose of this study was to examine the effects of short-acting beta agonist (albuterol) administration on estimated ventilatory capacity in children with asthma.

METHODS

Fifteen children (eleven boys, 10.6 ± 0.9 years) completed spirometry at baseline, after 180 µg of albuterol, and after the CPET in this cross-sectional study. Ventilatory capacity was calculated from forced vital capacity (FVC) and isovolume forced expiratory time from 25 to 75% of FVC (isoFET25-75) as follows: FVC/2 × [60/(2 × isoFET25-75)]. Differences in outcome variables between baseline, after albuterol administration, and after the CPET were detected with repeated measures mixed models with Bonferroni post hoc corrections.

RESULTS

Estimated ventilatory capacity was higher after albuterol (68.7 ± 21.2 L/min) and after the CPET (75.8 ± 25.6 L/min) when compared with baseline (60.9 ± 22.0 L/min; P = 0.003). Because forced vital capacity did not change, the increased ventilatory capacity was primarily due to a decrease in isoFET25-75 (i.e., an increase in mid-flows or isoFEF25-75).

CONCLUSION

Albuterol administration could be considered prior to CPET for children with asthma with relatively well-preserved FEV1 values to increase ventilatory capacity pre-exercise and potentially avoid symptom-limited early termination of testing.

β1-adrenergic receptor polymorphisms: a possible genetic predictor of bisoprolol response in acute coronary syndrome

Aim

To investigate the association between beta1-adrenergic receptor (ADRB1) polymorphisms and response to bisoprolol treatment in beta-blocker naive patients with acute coronary syndrome (ACS).

Patients & methods

Seventy-seven patients received bisoprolol for four weeks. Blood pressure and heart rate were measured at baseline and during treatment. TaqMan allelic discrimination method was utilized for ADRB1 Ser49Gly and Arg389Gly genotyping.

Results

Arg389Arg carriers showed greater reductions in systolic and diastolic blood pressure (-8.5% ± 7.8% vs -0.76% ± 8.7%, p = 0.000218), and (-9.5% ± 9.7% vs -0.80% ± 11.5%, p = 0.000149), respectively, compared with Gly389 carriers. No statistical difference was found for study's outcomes based on codon 49.

Conclusion

Arg389Gly polymorphism is a promising bisoprolol response predictor in ACS patients.

Pro-inflammatory action of formoterol in human bronchial epithelia

Despite the wide usage of β2-adrenoceptor agonists in asthma treatment, they do have side effects such as aggravating inflammation. We previously reported that isoprenaline induced Cl- secretion and IL-6 release via cAMP-dependent pathways in human bronchial epithelia, but the mechanisms underlying the inflammation-aggravation effects of β2-adrenoceptor agonists remain pooly understood. In this study, we investigated formoterol, a more specific β2-adrenoceptor agonist, -mediated signaling pathways involved in the production of IL-6 and IL-8 in 16HBE14o- human bronchial epithelia. The effects of formoterol were detected in the presence of PKA, exchange protein directly activated by cAMP (EPAC), cystic fibrosis transmembrane conductance regulator (CFTR), extracellular signal-regulated protein kinase (ERK)1/2 and Src inhibitors. The involvement of β-arrestin2 was determined using siRNA knockdown. Our results indicate that formoterol can induce IL-6 and IL-8 secretion in concentration-dependent manner. The PKA-specific inhibitor, H89, partially inhibited IL-6 release, but not IL-8. Another intracellular cAMP receptor, EPAC, was not involved in either IL-6 or IL-8 release. PD98059 and U0126, two ERK1/2 inhibitors, blocked IL-8 while attenuated IL-6 secretion induced by formoterol. Furthermore, formoterol-induced IL-6 and IL-8 release was attenuated by Src inhibitors, namely dasatinib and PP1, and CFTRinh172, a CFTR inhibitor. In addition, knockdown of β-arrestin2 by siRNA only suppressed IL-8 release when a high concentration of formoterol (1 μM) was used. Taken together, our results suggest that formoterol stimulates IL-6 and IL-8 release which involves PKA/Src/ERK1/2 and/or β-arrestin2 signaling pathways.

Pathophysiology, Therapeutic Targets, and Future Therapeutic Alternatives in COPD: Focus on the Importance of the Cholinergic System

Chronic obstructive pulmonary disease (COPD) is a progressive disease characterized by airway limitation and changes in airway structure. It has a high global burden of mortality and morbidity. The etiology of COPD is complex, but exposure to tobacco smoke and other inhaled lung oxidants are major risk factors. Both pharmacological and non-pharmacological approaches are used to manage COPD, but there remains an urgent unmet need for drugs that can modify the course of the disease. This review focuses on the role of acetylcholine and other components of the pulmonary cholinergic system in the pathogenesis of COPD, and the inhaled pharmacological agents that target it. In addition to its role as a neurotransmitter, acetylcholine regulates diverse aspects of COPD pathogenesis including bronchoconstriction, airway remodeling, mucus secretion and inflammation. Inhaled antimuscarinic drugs are a key component of therapy for COPD, as monotherapy or in combination with inhaled β2 agonists or corticosteroids. We review the evidence supporting the use of current anticholinergic agents in COPD and preview novel drugs targeting the cholinergic system and agents from other classes in clinical development, such as phosphodiesterase-4 inhibitors and monoclonal antibodies targeting inflammatory mediators.

Involvement of beta3-adrenergic receptors in relaxation mediated by nitric oxide in chicken basilar artery

The response of basilar arteries to noradrenaline varies among many animal species, but remains little studied in poultry. Accordingly, we aimed to characterize the adrenergic receptor (AR) subtypes that modulate vascular response in basilar arteries in the chicken, with isometric recording of arterial ring tension using an organ bath. We demonstrated the presence of both alpha and beta (α and β) receptor subtypes through evaluating the response to noradrenaline, with and without a range of β-AR and α-AR antagonists. The concentration-dependent relaxations then induced by a range of β-AR agonists indicated a potency ranking of isoproterenol > noradrenaline > adrenaline > procaterol. We then investigated the effects of β-AR antagonists that attenuate the effect of isoproterenol (propranolol for β_1,2,3-ARs, atenolol for β₁-ARs, butoxamine for β₂-ARs, and SR 59230A for β₃-ARs), with Schild regression analysis, ascertaining multiple β-AR subtypes, with neither the β₁-AR nor the β₂-AR as the dominant subtype. SR 59230A was the only antagonist to yield a pA₂ value (7.52) close to the reported equivalent for the relevant receptor subtype. Furthermore, treatment with SR 58611 (a β₃-AR agonist) induced relaxation, which was inhibited (P < 0.01) by L-NNA and SR 59230A. Additionally, treating basilar arterial strips (containing endothelium) with SR 58611 induced nitric oxide (NO) production, which was inhibited (P < 0.01) by L-NNA and SR 59230A. Based on this first characterization of AR subtypes in chicken basilar arteries (to our knowledge), we suggest that α- and β-ARs are involved in contraction and relaxation, and that β₃-ARs, especially those on the endothelium, may play an important role in vasodilation via NO release.

Unconventional interactions of the TRPV4 ion channel with beta-adrenergic receptor ligands

The transient receptor potential vanilloid 4 (TRPV4) ion channel is present in different tissues including those of the airways. This channel is activated in response to stimuli such as changes in temperature, hypoosmotic conditions, mechanical stress, and chemicals from plants, lipids, and others. TRPV4's overactivity and/or dysfunction has been associated with several diseases, such as skeletal dysplasias, neuromuscular disorders, and lung pathologies such as asthma and cardiogenic lung edema and COVID-19-related respiratory malfunction. TRPV4 antagonists and blockers have been described; nonetheless, the mechanisms involved in achieving inhibition of the channel remain scarce, and the search for safe use of these molecules in humans continues. Here, we show that the widely used bronchodilator salbutamol and other ligands of β-adrenergic receptors inhibit TRPV4's activation. We also demonstrate that inhibition of TRPV4 by salbutamol is achieved through interaction with two residues located in the outer region of the pore and that salbutamol leads to channel closing, consistent with an allosteric mechanism. Our study provides molecular insights into the mechanisms that regulate the activity of this physiopathologically important ion channel.

Antagonizing cholecystokinin A receptor in the lung attenuates obesity-induced airway hyperresponsiveness

Obesity increases asthma prevalence and severity. However, the underlying mechanisms are poorly understood, and consequently, therapeutic options for asthma patients with obesity remain limited. Here we report that cholecystokinin-a metabolic hormone best known for its role in signaling satiation and fat metabolism-is increased in the lungs of obese mice and that pharmacological blockade of cholecystokinin A receptor signaling reduces obesity-associated airway hyperresponsiveness. Activation of cholecystokinin A receptor by the hormone induces contraction of airway smooth muscle cells. In vivo, cholecystokinin level is elevated in the lungs of both genetically and diet-induced obese mice. Importantly, intranasal administration of cholecystokinin A receptor antagonists (proglumide and devazepide) suppresses the airway hyperresponsiveness in the obese mice. Together, our results reveal an unexpected role for cholecystokinin in the lung and support the repurposing of cholecystokinin A receptor antagonists as a potential therapy for asthma patients with obesity.

Effects of Adrenergic Receptor Stimulation on Human Hemostasis: A Systematic Review

Catecholamine stimulation over adrenergic receptors results in a state of hypercoagulability. Chronic stress involves the release and increase in circulation of catecholamines and other stress related hormones. Numerous observational studies in human have related stressful scenarios to several coagulation variables, but controlled stimulation with agonists or antagonists to adrenergic receptors are scarce. This systematic review is aimed at presenting an updated appraisal of the effect of adrenergic receptor modulation on variables related to human hemostasis by systematically reviewing the effect of adrenergic receptor-targeting drugs on scale variables related to hemostasis. By searching 3 databases for articles published between January 1st 2011 and February 16th, 2022 reporting effects on coagulation parameters from stimulation with α- or β-adrenergic receptor targeting drugs in humans regardless of baseline condition, excluding records different from original research and those not addressing the main aim of this systematic review. Risk of bias assessed using the Revised Cochrane risk-of-bias tool for randomized trials (RoB 2). Tables describing a pro-thrombotic anti-fibrinolytic state induced after β-adrenergic receptor agonist stimulation and the opposite after α1-, β-adrenergic receptor antagonist stimulation were synthesized from 4 eligible records by comparing hemostasis-related variables to their baseline. Notwithstanding this low number of records, experimental interventions included were sound and mostly unbiased, results were coherent, and outcomes were biologically plausible. In summary, this systematic review provides a critical systematic assessment and an updated elaboration, and its shortcomings highlight the need for further investigation in the field of hematology.

Recent advances in the treatment of childhood asthma: a clinical pharmacology perspective

INTRODUCTION

Childhood asthma is a complex heterogenous inflammatory disease that can pose a large burden on patients and their caregivers. There is a strong need to adapt asthma treatment to the individual patient taking into account underlying inflammatory profiles, moving from a 'one size fits all' approach toward a much-needed personalized approach.

AREAS COVERED

This review article aims to provide an overview of recent advances in the management and treatment of pediatric asthma, including novel insights on the molecular heterogeneity of childhood asthma, the emergence of biologicals to treat severe asthma, and innovative e-health and home monitoring techniques to make asthma management more convenient and accessible.

EXPERT OPINION

Molecular technologies have provided new treatment leads. E-health and home monitoring technologies have helped to gain more insights into disease dynamics and improve adherence to treatment while bringing health care to the patient. However, uncontrolled childhood asthma is still a major unmet clinical need and precision-medicine approaches are still scarce in clinical practice. Advanced omics methods may help researchers or clinicians to more accurately phenotype and treat subtypes of childhood asthma and gain more insight into the complexity of the disease.

Severe lactic acidosis and persistent diastolic hypotension following standard dose of intermittent nebulized salbutamol in a child: a case report

Background

Salbutamol is a selective β2-receptor agonist widely used to treat asthma in both emergency and outpatient settings. However, it has been associated with a broad spectrum of side effects. Lactic acidosis and diastolic hypotension are rarely reported together following intermittent salbutamol nebulization in children, even less so at standard therapeutic doses.

Case presentation

We present the case of a 12-year-old Italian boy, 34 kg body weight, who experienced a serious drug reaction during a moderate asthma exacerbation with associated dehydration (blood urea nitrogen/creatinine 0.25), following intermittent inhaled (0.2 mg at 3-hour intervals—overall 1.4 mg in 24 hours before arrival) and nebulized treatment (3.25 mg at 20-minute intervals in 60 minutes, overall 11.25 mg in our emergency department). The patient developed hyperglycemia (peak concentration 222 mg/dL), hypokalemia (lowest concentration 2.6 mEq/L), electrocardiogram alterations (corrected QT interval 467 ms), long-lasting arterial hypotension despite fluid boluses (lowest value 87/33 mmHg), and elevated blood lactate levels (peak concentration 8.1 mmol/L), following the third nebulized dose. Infections, liver dysfunction, and toxicity following other medications were ruled out. The aforementioned alterations improved within 24 hours after discontinuation of salbutamol.

Conclusions

We reinforce the message that even the use of intermittent nebulized salbutamol for acute moderate asthma can lead to severe transient complications in children. Then, healthcare providers should pay attention not only in emergency settings, to achieve prompt recognition and proper management of this adverse reaction. Careful reassessment could prevent similar reactions.

Discovery of a Highly Selective β2-Adrenoceptor Agonist with a 2-Amino-2-phenylethanol Scaffold as an Oral Antiasthmatic Agent

Asthma patients in resource-poor countries cannot obtain adequate basic asthma medications because most asthma medications are supplied as inhalants. An alternative approach is to create oral antiasthmatic drugs with high β₂/β₁-selectivity, which should reduce treatment costs. In this study, we designed a cohort of compounds 1 using 2-(4-amino-3-chloro-5-(trifluoromethyl)phenyl)-2-(tert-butylamino)ethan-1-ol hydrogen chloride (1a) as the lead compound with an aim to expand the library of compounds possessing the 2-amino-2-phenylethanol scaffold. Structure-activity relationship studies on these compounds revealed that compounds created showed remarkable β₂ selectivity compared to isoproterenol and gave additional insights on the rational design of β₂-adrenoceptor agonists. Moreover, 1a was found as the best candidate compound showing the greatest potential for drug development. Cell-based assays showed that 1a was about 10 times more selective than salbutamol toward the β₂-adrenoceptor. Moreover, 1a exhibited good oral bioavailability and low acute oral toxicity. These data reveal 1a as an oral antiasthmatic agent.

Association between beta-2 adrenergic receptor variants and clinical outcomes in children and adolescents with acute asthma

Objective

To investigate whether different genotypes of p.Arg16Gly, p.Gln27Glu, p.Arg19Cys and p.Thr164Ile variants interfere in response to treatment in children and adolescents with moderate to severe acute asthma.

Methods

This sample comprised patients aged 2 to 17 years with a history of at least two wheezing episodes and current moderate to severe asthma exacerbation. All patients received multiple doses of albuterol and ipratropium bromide delivered via pressurized metered-dose inhaler with holding chamber and systemic corticosteroids. Hospital admission was defined as the primary outcome. Secondary outcomes were changes in forced expiratory volume in the first second after 1 hour of treatment, and for outpatients, length of stay in the emergency room. Variants were genotyped by sequencing.

Results

A total of 60 patients were evaluated. Hospital admission rates were significantly higher in carriers of the genotype AA relative to those with genotype AG or GG, within the p.Arg16Gly variant (p=0.03, test χ², alpha=0.05). Secondary outcomes did not differ between genotypes.

Conclusion

Hospital admission rates were significantly higher among carriers of the genotype AA within the p.Arg16Gly variant. Trial registration: ClinicalTrials.gov: NCT01323010

An overview on the RSV-mediated mechanisms in the onset of non-allergic asthma

Respiratory syncytial virus (RSV) infection is recognized as an important risk factor for wheezing and asthma, since it commonly affects babies during lung development. While the role of RSV in the onset of atopic asthma is widely recognized, its impact on the onset of non-atopic asthma, mediated via other and independent causal pathways, has long been also suspected, but the association is less clear. Following RSV infection, the release of local pro-inflammatory molecules, the dysfunction of neural pathways, and the compromised epithelial integrity can become chronic and influence airway development, leading to bronchial hyperreactivity and asthma, regardless of atopic status. After a brief review of the RSV structure and its interaction with the immune system and neuronal pathways, this review summarizes the current evidence about the RSV-mediated pathogenic pathways in predisposing and inducing airway dysfunction and non-allergic asthma development.

β2-Adrenoceptor Activation Stimulates IL-6 Production via PKA, ERK1/2, Src, and Beta-Arrestin2 Signaling Pathways in Human Bronchial Epithelia

OBJECTIVE

β2-Adrenoceptor agonists are widely used to treat asthma because of their bronchial-dilation effects. We previously reported that isoprenaline, via the apical and basolateral β2-adrenoceptor, induced Cl- secretion by activating cyclic AMP (cAMP)-dependent pathways in human bronchial epithelia. Despite these results, whether and how the β2-adrenoceptor-mediated cAMP-dependent pathway contributes to pro-inflammatory cytokine release in human bronchial epithelia remains poorly understood.

METHODS

We investigated β2-adrenoceptor-mediated signaling pathways involved in the production of two pro-inflammatory cytokines, interleukin (IL)-6 and IL-8, in 16HBE14o- human bronchial epithelia. The effects of isoprenaline or formoterol were assessed in the presence of protein kinase A (PKA), exchange protein directly activated by cAMP (EPAC), Src, and extracellular signal-regulated protein kinase (ERK)1/2 inhibitors. The involvement of β-arrestin2 was examined using siRNA knockdown.

RESULTS

Isoprenaline and formoterol (both β2 agonists) induced IL-6, but not IL-8, release, which could be inhibited by ICI 118,551 (β2 antagonist). The PKA-specific inhibitor, H89, partially inhibited IL-6 release. Another intracellular cAMP receptor, EPAC, was not involved in IL-6 release. Isoprenaline-mediated IL-6 secretion was attenuated by dasatinib, a Src inhibitor, and PD98059, an ERK1/2 inhibitor. Isoprenaline treatment also led to ERK1/2 phosphorylation. In addition, knockdown of β-arrestin2 by siRNA specifically suppressed cytokine release when a high concentration of isoprenaline (1 mM) was used.

CONCLUSION

Our results suggest that activation of the β2-adrenoceptor in 16HBE14o- cells stimulated the PKA/Src/ERK1/2 and/or β-arrestin2 signaling pathways, leading to IL-6 release. Therefore, our data reveal that β2-adrenoceptor signaling plays a role in the immune regulation of human airway epithelia.

Inhaled Therapies for Asthma and Chronic Obstructive Pulmonary Disease

Asthma and chronic obstructive pulmonary disease (COPD) are obstructive lung diseases which are characterized by chronic inflammation and an increase in mucus production, and are highly prevalent conditions. Despite recent advances and multiple available therapies, there remains a significant unmet medical need. Over the past 40 years, the introduction of new classes of safe and effective therapy is insufficient. In spite of the high burden of asthma and COPD among patients, there are fewer new approved therapies in comparison to cardiovascular, metabolic and neurological diseases due to few drug candidates and a higher failure rate in the development of respiratory medicine. Lung diseases are amongst the leading causes of death globally with asthma being one of the most prevalent respiratory diseases, which affects people of all ages but, despite effective therapies available, many patients are poorly controlled and have a low quality of life. COPD is currently ranked as the fourth cause of death worldwide and predicted to become the third leading cause of death in 2030. The development of more effective treatments is urgently needed in order to reduce the high mortality rate and the enormous suffering from asthma and COPD. Various inhalation devices with different classes of medications are the foundation as therapies in both asthma and COPD. This article gives a comprehensive review of the promising inhaled therapies in the treatment of asthma and COPD. However, the lack of disease control in asthma and COPD patients may be due to numerous reasons. The association between non-adherence to guidelines on the part of the health care provider and poor inhalation technique and/or non-adherence to the prescribed treatment plan by the patients is common. It is therefore essential to discuss the different delivery systems and the methods used in asthma and COPD patients.

Subtype selective fluorescent ligands based on ICI 118,551 to study the human β2-adrenoceptor in CRISPR/Cas9 genome-edited HEK293T cells at low expression levels

Fluorescent ligand technologies have proved to be powerful tools to improve our understanding of ligand‐receptor interactions. Here we have characterized a small focused library of nine fluorescent ligands based on the highly selective β₂‐adrenoceptor (β₂AR) antagonist ICI 118,551. The majority of fluorescent ICI 118,551 analogs had good affinity for the β₂AR (pK_D >7.0) with good selectivity over the β₁AR (pK_D <6.0). The most potent and selective ligands being 8c (ICI 118,551‐Gly‐Ala‐BODIPY‐FL‐X; β₂AR pK_D 7.48), 9c (ICI 118,551‐βAla‐βAla‐BODIPY‐FL‐X; β₂AR pK_D 7.48), 12a (ICI 118,551‐PEG‐BODIPY‐X‐630/650; β₂AR pK_D 7.56), and 12b (ICI 118,551‐PEG‐BODIPY‐FL; β₂AR pK_D 7.42). 9a (ICI 118,551‐βAla‐βAla‐BODIPY‐X‐630/650) had the highest affinity at recombinant β₂ARs (pK_D 7.57), but also exhibited significant binding affinity to the β₁AR (pK_D 6.69). Nevertheless, among the red fluorescent ligands, 9a had the best imaging characteristics in recombinant HEK293 T cells and labeling was mostly confined to the cell surface. In contrast, 12a showed the highest propensity to label intracellular β₂ARs in HEK293 T cell expressing exogenous β₂ARs. This suggests that a combination of the polyethylene glycol (PEG) linker and the BODIPY‐X‐630/650 makes this ICI 118,551 derivative particularly susceptible to crossing the cell membrane to access the intracellular β₂ARs. We have also used these ligands in combination with CRISPR/Cas9 genome‐edited HEK293 T cells to undertake for the first time real‐time ligand binding to native HEK293 T β₂ARs at low native receptor expression levels. These studies provided quantitative data on ligand‐binding characteristics but also allowed real‐time visualization of the ligand‐binding interactions in genome‐edited cells using NanoBRET luminescence imaging.

Heavy Metal Assessment in Feathers of Eurasian Magpies (Pica pica): A Possible Strategy for Monitoring Environmental Contamination?

In the present study, the Eurasian magpie (Pica pica), was evaluated as a possible bioindicator of environmental pollution by heavy metals (HMs). Levels of Ni, Pb, Cd, and Hg in feathers of 64 magpies (31 males and 33 females) were measured by ICP-MS technique. Plasmatic biomarkers of oxidative stress (OS) were also assessed. The birds were captured in the province of Parma (Italy), in different capture sites within 1 km from urban area (UZ), and farther than 5 km from urban area (RZ). Median HM levels were 0.68 mg/kg (0.18–2.27), 2.80 mg/kg (0.41–17.7), <limit of detection (LOD) mg/kg (<LOD–0.25), 3.90 mg/kg (1.35–85.9) for Ni, Pb, Cd and Hg, respectively. No significant differences in HM levels were found according to sex, while Ni and Pb were significantly higher in adult compared to young birds (p = 0.047, p = 0.004). Conversely, Cd and Hg levels in young magpies resulted higher than those of adults (p = 0.001 and p = 0.004). No correlation was found between OS biomarkers and HM levels. No differences were found in HM levels according to capture area, except for Hg level, which resulted higher in magpies of RZ (4.05 mg/kg (1.35–12.7)) compared to UZ (2.99 mg/kg (1.54–85.9)). Further experiments are needed to establish whether magpie feathers could represent a suitable non-invasive tool for biomonitoring HMs in the environment.

Airway relaxation mechanisms and structural basis of osthole for improving lung function in asthma

Overuse of β2-adrenoceptor agonist bronchodilators evokes receptor desensitization, decreased efficacy, and an increased risk of death in asthma patients. Bronchodilators that do not target β2-adrenoceptors represent a critical unmet need for asthma management. Here, we characterize the utility of osthole, a coumarin derived from a traditional Chinese medicine, in preclinical models of asthma. In mouse precision-cut lung slices, osthole relaxed preconstricted airways, irrespective of β2-adrenoceptor desensitization. Osthole administered in murine asthma models attenuated airway hyperresponsiveness, a hallmark of asthma. Osthole inhibited phosphodiesterase 4D (PDE4D) activity to amplify autocrine prostaglandin E2 signaling in airway smooth muscle cells that eventually triggered cAMP/PKA-dependent relaxation of airways. The crystal structure of the PDE4D complexed with osthole revealed that osthole bound to the catalytic site to prevent cAMP binding and hydrolysis. Together, our studies elucidate a specific molecular target and mechanism by which osthole induces airway relaxation. Identification of osthole binding sites on PDE4D will guide further development of bronchodilators that are not subject to tachyphylaxis and would thus avoid β2-adrenoceptor agonist resistance.

Attenuation of relaxing response induced by pituitary adenylate cyclase-activating polypeptide in bronchial smooth muscle of experimental asthma

Bronchomotor tone is regulated by contraction and relaxation of airway smooth muscle (ASM). A weakened ASM relaxation might be a cause of airway hyperresponsiveness (AHR), a characteristic feature of bronchial asthma. Pituitary adenylyl cyclase-activating polypeptide (PACAP) is known as a mediator that causes ASM relaxation. To date, whether or not the PACAP responsiveness is changed in asthmatic ASM is unknown. The current study examined the hypothesis that relaxation induced by PACAP is reduced in bronchial smooth muscle (BSM) of allergic asthma. The ovalbumin (OA)-sensitized mice were repeatedly challenged with aerosolized OA to induce asthmatic reaction. Twenty-four hours after the last antigen challenge, the main bronchial smooth muscle (BSM) tissues were isolated. Tension study showed a BSM hyperresponsiveness to acetylcholine in the OA-challenged mice. Both quantitative RT-PCR and immunoblot analyses revealed a significant decrease in PAC₁ receptor expression in BSMs of the diseased mice. Accordingly, in the antigen-challenged group, the PACAP-induced PAC₁ receptor-mediated BSM relaxation was significantly attenuated, whereas the relaxation induced by vasoactive intestinal polypeptide was not changed. These findings suggest that the relaxation induced by PACAP is impaired in BSMs of experimental asthma due to a downregulation of its binding partner PAC₁ receptor. Impaired BSM responsiveness to PACAP might contribute to the AHR in asthma.

Testosterone augments β2 adrenergic receptor genomic transcription increasing salbutamol relaxation in airway smooth muscle

Androgens in asthmatic men may be linked to asthma severity, acting via nongenomic and genomic effects. This ailment affects boys more than girls during infancy, and this proportion reverses in puberty. Plasmatic androgen concentration in young men increases at this age and might be related to lower asthma symptoms. Nongenomic actions occur in a brief period and are independent of the androgen receptor (AR), while genomic effects depend on AR, take hours-days and are modified by transcription or protein synthesis inhibitors. Guinea pig tracheas chronic incubation with testosterone (TES, 40 nM, 48 h) potentiates salbutamol-induced relaxation, an effect that was reversed by flutamide, not observed when tissues were pre-incubated with TES-bovine serum albumin (TES-BSA) nor when tissues were preincubated with TES for 15-60 min. In tracheal myocytes, TES chronic incubation increases salbutamol-induced K⁺ currents (IK⁺), an effect that was also reversed by flutamide, actinomycin D and cycloheximide and not seen with TES-BSA. The increment in IK⁺ was blocked by 4-aminopyridine and iberiotoxin, indicating that delayed rectifier K⁺ and high-conductance Ca²⁺ activated K⁺ channels were involved in the TES potentiation effect. Immunofluorescence studies showed that chronic TES augmented the β₂ adrenergic receptor (β₂-AR) expression in ASM and this finding was corroborated by q-PCR and Western blot assays. β₂-AR affinity for salbutamol after TES incubation was increased. In conclusion, chronic exposure to physiological TES concentration of the guinea pig ASM promotes β₂-AR upregulation favoring β₂ adrenergic responses and probably limiting the severity of the asthmatic exacerbations in teenage boys and men.

A comparative study on the influence of an ivy preparation and an ivy/thyme combination on the β2-adrenergic signal transduction

The β₂-adrenergic receptor (β₂AR) is relevant for surfactant formation in alveolar type 2 cells and reduction of intracellular calcium concentration in bronchial muscle cells and thus for secretolytic and bronchospasmolytic effects. Herbal medicinal products that affect the β₂AR system are used to treat common cold and bronchitis accompanied with mucus covered and narrowed airways. The present work compares the influence of an ivy preparation and an ivy/thyme combination on the β₂-adrenergic signal transduction. For receptor binding studies and characterization of the lateral mobility of β₂AR we have used single molecule detection by fluorescence correlation spectroscopy and single particle tracking. For the determination of both the second messenger cAMP and the internalization of β₂AR we have generated luciferase based reporter cell lines, which produce a cAMP-dependent luciferase in the cytosol and express β₂AR with extracellular luciferase moiety in the plasma membrane. While both preparations increased the β₂AR binding, a significant increase of the cAMP level was observed only for the ivy preparation, which can be explained by the inhibited internalization of HiBiT-tagged β₂AR under stimulating conditions. In contrast, isoprenaline-mediated internalization of HiBiT-tagged β₂AR of ivy/thyme combination pre-treated cells was not inhibited. Cells comparatively pre-treated with a thyme preparation did not show inhibition of ß₂AR internalization either. Furthermore, SNAP-tagged β₂AR of ivy preparation pre-treated cells, which were not internalized after isoprenaline stimulation, showed a redistribution from fast-to-slowly diffusing β₂AR. A corresponding redistribution of these receptors was not observed after pre-treatment with both the ivy/thyme combination and the thyme preparation. Comparable to the ivy/thyme combination, no decrease in the intratrack transitioning probability ratio (p23/p32) for fast and slow diffusing β₂AR was found for the thyme preparation, which, however, significantly decreased for control cells and for pre-treatment with the ivy preparation under stimulating conditions. It can therefore be concluded that the thyme fluid extract fraction in the ivy/thyme combination may have in part a negative effect on the β₂-adrenergic signal transduction.

Heart failure with preserved ejection fraction: present status and future directions

The clinical importance of heart failure with preserved ejection fraction (HFpEF) has recently become apparent. HFpEF refers to heart failure (HF) symptoms with normal or near-normal cardiac function on echocardiography. Common clinical features of HFpEF include diastolic dysfunction, reduced compliance, and ventricular hypokinesia. HFpEF differs from the better-known HF with reduced ejection fraction (HFrEF). Despite having a "preserved ejection fraction," patients with HFpEF have symptoms such as shortness of breath, excessive tiredness, and limited exercise capability. Furthermore, the mortality rate and cumulative survival rate are as severe in HFpEF as they are in HFrEF. While beta-blockers and renin-angiotensin-aldosterone system modulators can improve the survival rate in HFrEF, no known therapeutic agents show similar effectiveness in HFpEF. Researchers have examined molecular events in the development of HFpEF using small and middle-sized animal models. This review discusses HFpEF with regard to etiology and clinical features and introduces the use of mouse and other animal models of human HFpEF.

Design, synthesis and biological evaluation of 8-(2-amino-1-hydroxyethyl)-6-hydroxy-1,4-benzoxazine-3(4H)-one derivatives as potent β2-adrenoceptor agonists

A series of β₂-adrenoceptor agonists with an 8-(2-amino-1-hydroxyethyl)-6-hydroxy-1,4-benzoxazine-3(4H)-one moiety is presented. The stimulatory effects of the compounds on human β₂-adrenoceptor and β₁-adrenoceptor were characterized by a cell-based assay. Their smooth muscle relaxant activities were tested on isolated guinea pig trachea. Most of the compounds were found to be potent and selective agonists of the β₂-adrenoceptor. One of the compounds, (R)-18c, possessed a strong β₂-adrenoceptor agonistic effect with an EC₅₀ value of 24 pM. It produced a full and potent airway smooth muscle relaxant effect same as olodaterol. Its onset of action was 3.5 min and its duration of action was more than 12 h in an in vitro guinea pig trachea model of bronchodilation. These results suggest that (R)-18c is a potential candidate for long-acting β₂-AR agonists.

Relaxing effects of clenbuterol, ritodrine, salbutamol and fenoterol on the contractions of horse isolated bronchi induced by different stimuli

β₂-adrenoceptor agonists are considered the most effective drugs to counteract bronchoconstriction in horses with asthma, but only clenbuterol is commonly employed in clinical practice. We evaluated the effects of different selective β₂ agonists: clenbuterol, ritodrine, salbutamol, and fenoterol on the contractions of isolated bronchial muscle of horses induced by electrical field stimulation (EFS), carbachol, histamine, and KCl. All β₂ agonists reduced the amplitude of contraction induced by the different stimuli but with variable efficacy and potency. Fenoterol and salbutamol were more effective than clenbuterol in relaxing the bronchial contractions induced by EFS and histamine, and were able to completely abolish carbachol-induced contractions, unlike clenbuterol and ritodrine. The respective potency values (pEC₅₀) of clenbuterol, ritodrine, salbutamol, and fenoterol were 7.74 ± 0.20, 7.77 ± 0.17, 7.30 ± 0.23, 8.01 ± 0.13, for EFS-induced contractions; 8.39 ± 0.26, 5.49 ± 0.28, 6.63 ± 0.14, 7.68 ± 0.11, for carbachol-induced contraction; 7.39 ± 0.27, 7.04 ± 0.28, 6.45 ± 0.34, 7.34 ± 0.22, for histamine-induced contraction; 7.15 ± 0.06, 6.07 ± 0.20, 6.48 ± 0.14, 6.70 ± 0.18, for KCl-induced contraction. Salbutamol and fenoterol showed a higher efficacy than clenbuterol in relaxing horse bronchial muscle pre-contracted by most stimuli. Clenbuterol displayed a good potency but a rather low efficacy, and this may be due to its partial agonist nature; ritodrine showed lower or not significantly different efficacy and potency compared to the other agonists. An evaluation of the clinical efficacy by fenoterol and salbutamol in horses with asthma could be of great interest to assess if they could represent more effective bronchodilators compared to clenbuterol.

The Effects of Inhaled Terbutaline on 3-km Running Time-Trial Performance

Terbutaline is a prohibited drug except for athletes with a therapeutic use exemption certificate; terbutaline's effects on endurance performance are relatively unknown. Purpose: To investigate the effects of 2 therapeutic (2 and 4 mg) inhaled doses of terbutaline on 3-km running time-trial performance. Methods: A total of 8 men (age 24.3 [2.4] y; weight 77.6 [8] kg; and height 179.5 [4.3] cm) and 8 women (age 22.4 [3] y; weight 58.6 [6] kg; and height 163 [9.2] cm) free from respiratory disease and illness provided written informed consent. Participants completed 3-km running time trials on a nonmotorized treadmill on 3 separate occasions following placebo and 2- and 4-mg inhaled terbutaline in a single-blind, repeated-measures design. Urine samples (15 min postexercise) were analyzed for terbutaline concentration. Data were analyzed using 1-way repeated-measures analysis of variance, and significance was set at P < .05 for all analyses. Results: No differences were observed for completion times (1103 [201] s, 1106 [195] s, 1098 [165] s; P = .913) for the placebo or 2- and 4-mg inhaled trials, respectively. Lactate values were higher (P = .02) after 4 mg terbutaline (10.7 [2.3] mmol·L^-1) vs placebo (8.9 [1.8] mmol·L^-1). Values of forced expiratory volume in the first second of expiration (FEV₁) were greater after inhalation of 2 mg (5.08 [0.2]; P = .01) and 4 mg terbutaline (5.07 [0.2]; P = .02) compared with placebo (4.83 [0.5] L) postinhalation. Urinary terbutaline concentrations were mean 306 (288) ng·mL^-1 and 435 (410) ng·mL^-1 (P = .2) and peak 956 ng·mL^-1 and 1244 ng·mL^-1 after 2 and 4 mg inhaled terbutaline, respectively. No differences were observed between the male and female participants. Conclusions: Therapeutic dosing of terbutaline does not lead to an improvement in 3-km running performance despite significantly increased FEV₁. The findings suggest that athletes using inhaled terbutaline at high therapeutic doses to treat asthma will not gain an ergogenic advantage during 3-km running performance.

ADRB2 suppresses IL-13-induced allergic rhinitis inflammatory cytokine regulated by miR-15a-5p

Allergic rhinitis (AR) is a common hypersensitive disease that troubles patients a lot. Nasal epithelial cells (NECs), as the outmost protection of inhalation, play an important role in AR allergic response. Adrenoceptor beta 2 (ADRB2) is an important gene in inflammatory response, which has become the hot spot for AR development and treatment in recent years. MiR-15a-5p has been proved to be involved in AR immune response as the upstream regulator of ADRB2. Human primary NECs were isolated and stimulated by IL-13. qRT-PCR assay was used to detect the RNA level of target genes. ELISA and Western blotting were applied to detect target protein levels. Luciferase reporter assay and biotin pull-down assay were performed to test molecules interaction. ADRB2 was highly expressed in nasal mucosa of AR patients and was positively correlated with IL-13 stimulation, and knockdown of ADRB2 inhibited IL-13-induced expression of GM-CSF, eotaxin, and MUC5AC in NECs. ADRB2 was directly targeted by miR-15a-5p, and miR-15a-5p inhibited IL-13-induced expression of GM-CSF, eotaxin, and MUC5AC in NECs. ADRB2 mediated the effect of miR-15a-5p on the regulation of nasal epithelial immune responses. ADRB2 is negatively regulated by miR-15a-5p, which inhibits IL-13-induced nasal epithelial inflammatory responses.

Targeted Treatments for Chronic Obstructive Pulmonary Disease (COPD) Using Low-Molecular-Weight Drugs (LMWDs)

Chronic obstructive pulmonary disease (COPD) is a very common and frequently fatal airway disease. Current therapies for COPD depend mainly on long-acting bronchodilators, which cannot target the pathogenic mechanisms of chronic inflammation in COPD. New pharmaceutical therapies for the inflammatory processes of COPD are urgently needed. Several anti-inflammatory targets have been identified based on increased understanding of the pathogenesis of COPD, which raises new hopes for targeted treatment of this fatal respiratory disease. In this review, we discuss the recent advances in bioactive low-molecular-weight drugs (LMWDs) for the treatment of COPD and, in addition to the first-line drug bronchodilators, focus particularly on low-molecular-weight anti-inflammatory agents, including modulators of inflammatory mediators, inflammasome inhibitors, protease inhibitors, antioxidants, PDE4 inhibitors, kinase inhibitors, and other agents. We also provide new insights into targeted COPD treatments using LMWDs, particularly small-molecule agents.

Combined aclidinium bromide and long-acting beta2-agonist for chronic obstructive pulmonary disease (COPD)

BACKGROUND

Several dual bronchodilator combinations of long-acting beta2-agonist (LABA) and long-acting muscarinic antagonist (LAMA) have been approved for treatment of stable chronic obstructive pulmonary disease (COPD). The current GOLD (Global Initiative for Chronic Obstructive Lung Disease) recommendations suggest the use of LABA/LAMA combinations in people with group B COPD with persistent symptoms, group C COPD with further exacerbations on LAMA therapy alone and group D COPD with or without inhaled corticosteroids (ICS). Fixed-dose combination (FDC) of aclidinium/formoterol is one of the approved LABA/LAMA therapies for people with stable COPD.

OBJECTIVES

To assess the efficacy and safety of combined aclidinium bromide and long-acting beta2-agonists in stable COPD.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register (CAGR), ClinicalTrials.gov, World Health Organization (WHO) trials portal, United States Food and Drug Administration (FDA) and manufacturers' websites as well as the reference list of published trials up to 12 October 2018.

SELECTION CRITERIA

Parallel-group randomised controlled trials (RCTs) assessing combined aclidinium bromide and LABAs in people with stable COPD.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane for data collection and analysis. The primary outcomes were exacerbations requiring a short course of an oral steroid or antibiotic, or both; quality of life measured by a validated scale and non-fatal serious adverse events (SAEs). Where the outcome or study details were not reported, we contacted the study investigators or pharmaceutical company trial co-ordinators (or both) for missing data.

MAIN RESULTS

We identified RCTs comparing aclidinium/formoterol FDC versus aclidinium, formoterol or placebo only. We included seven multicentre trials of four to 52 weeks' duration conducted in outpatient settings. There were 5921 participants, whose mean age ranged from 60.7 to 64.7 years, mostly men with a mean smoking pack-years of 46.4 to 61.3 of which 43.9% to 63.4% were current smokers. They had a moderate-to-severe degree of COPD with a mean postbronchodilator forced expiratory volume in one second (FEV1) between 50.5% and 61% of predicted normal and the baseline mean FEV1 of 1.23 L to 1.43 L. We assessed performance and detection biases as low for all studies whereas selection, attrition and reporting biases were either low or unclear.FDC versus aclidiniumThere was no evidence of a difference between FDC and aclidinium for exacerbations requiring steroids or antibiotics, or both (OR 0.95, 95% CI 0.71 to 1.27; 2 trials, 2156 participants; moderate-certainty evidence); quality of life measured by St George's Respiratory Questionnaire (SGRQ) total score (MD -0.92, 95% CI -2.15 to 0.30); participants with significant improvement in SGRQ score (OR 1.17, 95% CI 0.97 to 1.41; 2 trials, 2002 participants; moderate-certainty evidence); non-fatal SAE (OR 1.19, 95% CI 0.79 to 1.80; 3 trials, 2473 participants; moderate-certainty evidence); hospital admissions due to severe exacerbations (OR 0.62, 95% CI 0.29 to 1.29; 2 trials, 2156 participants; moderate-certainty evidence) or adverse events (OR 0.95, 95% CI 0.76 to 1.18; 3 trials, 2473 participants; moderate-certainty evidence). Compared with aclidinium, FDC improved symptoms (Transitional Dyspnoea Index (TDI) focal score: MD 0.37, 95% CI 0.07 to 0.68; 2 trials, 2013 participants) with a higher chance of achieving a minimal clinically important difference (MCID) of at least one unit improvement (OR 1.34, 95% CI 1.11 to 1.62; high-certainty evidence); the number needed to treat for an additional beneficial outcome (NNTB) being 14 (95% CI 9 to 39).FDC versus formoterolWhen compared to formoterol, combination therapy reduced exacerbations requiring steroids or antibiotics, or both (OR 0.78, 95% CI 0.62 to 0.99; 3 trials, 2694 participants; high-certainty evidence); may decrease SGRQ total score (MD -1.88, 95% CI -3.10 to -0.65; 2 trials, 2002 participants; low-certainty evidence; MCID for SGRQ is 4 units); increased TDI focal score (MD 0.42, 95% CI 0.11 to 0.72; 2 trials, 2010 participants) with more participants attaining an MCID (OR 1.30, 95% CI 1.07 to 1.56; high-certainty evidence) and an NNTB of 16 (95% CI 10 to 60). FDC lowered the risk of adverse events compared to formoterol (OR 0.78, 95% CI 0.65 to 0.93; 5 trials, 3140 participants; high-certainty evidence; NNTB 22). However, there was no difference between FDC and formoterol for hospital admissions, all-cause mortality and non-fatal SAEs.FDC versus placeboCompared with placebo, FDC demonstrated no evidence of a difference in exacerbations requiring steroids or antibiotics, or both (OR 0.82, 95% CI 0.60 to 1.12; 2 trials, 1960 participants; moderate-certainty evidence) or hospital admissions due to severe exacerbations (OR 0.55, 95% CI 0.25 to 1.18; 2 trials, 1960 participants; moderate-certainty evidence), although estimates were uncertain. Quality of life measure by SGRQ total score was significantly better with FDC compared to placebo (MD -2.91, 95% CI -4.33 to -1.50; 2 trials, 1823 participants) resulting in a corresponding increase in SGRQ responders who achieved at least four units decrease in SGRQ total score (OR 1.72, 95% CI 1.39 to 2.13; high-certainty evidence) with an NNTB of 7 (95% CI 5 to 12). FDC also improved symptoms measured by TDI focal score (MD 1.32, 95% CI 0.96 to 1.69; 2 studies, 1832 participants) with more participants attaining at least one unit improvement in TDI focal score (OR 2.51, 95% CI 2.02 to 3.11; high-certainty evidence; NNTB 4). There were no differences in non-fatal SAEs, adverse events and all-cause mortality between FDC and placebo.Combination therapy significantly improved trough FEV1 compared to aclidinium, formoterol or placebo.

AUTHORS' CONCLUSIONS

FDC improved dyspnoea and lung function compared to aclidinium, formoterol or placebo, and this translated into an increase in the number of responders on combination treatment. Quality of life was better with combination compared to formoterol or placebo. There was no evidence of a difference between FDC and monotherapy or placebo for exacerbations, hospital admissions, mortality, non-fatal SAEs or adverse events. Studies reported a lower risk of moderate exacerbations and adverse events with FDC compared to formoterol; however, larger studies would yield a more precise estimate for these outcomes.

Design, synthesis and biological evaluation of 5-(2-amino-1-hydroxyethyl)-8-hydroxyquinolin-2(1H)-one derivatives as potent β2-adrenoceptor agonists

A series of novel β₂-adrenoceptor agonists with a 5-(2-amino-1-hydroxyethyl)-8-hydroxyquinolin-2(1H)-one moiety was designed, synthesized and evaluated for biological activity in human embryonic kidney 293 cells and isolated guinea pig trachea. Compounds 9g and (R)-18c exhibited the most excellent β₂-adrenoceptor agonistic effects and high β₂/β₁-selectivity with EC₅₀ values of 36 pM for 9g and 21 pM for (R)-18c. They produced potent airway smooth muscle relaxant effects with fast onset of action and long duration of action in an in vitro guinea pig trachea model of bronchodilation. These results support further development of the two compounds into drug candidates.

Bidirectional influence of amygdala β1-adrenoceptors blockade on cannabinoid signaling in contextual and auditory fear memory

The basolateral amygdala (BLA) is a major target and modulator of stress and has a critical role in the neural circuitry presenting learned fear behaviors. On the other hand, both the endocannabinoid and noradrenergic systems may be involved in regulating the stress responses, fear, and anxiety. Considering the aforementioned, we have investigated the involvement of the BLA β₁-adrenoceptors in conditioned fear responses induced by ACPA, a CB1 receptor (CB1R) agonist. In adult male NMRI mice, freezing responses to context and cue were measured using a Pavlovian fear conditioning apparatus. Pre-training intra-BLA microinjection of xamoterol (0.01 and 0.02 µg/mouse), a partial β₁-adrenoceptor agonist, or atenolol (0.5 µg/mouse), a β₁-adrenoceptor antagonist, decreased freezing behavior, which suggests an impairment of contextual and auditory fear retrieval. Similar results were found with pre-training intraperitoneal administration of ACPA (0.5 mg/kg). A sub-threshold dose of xamoterol, infused into the BLA, decreased ACPA (0.005 and 0.05 mg/kg) effect on both memories, while atenolol increased ACPA response to the context at the middle dose and decreased ACPA response to the tone at the lower dose. It can be concluded that the blockade of BLA β₁-adrenoceptors differentially affects ACPA response on the contextual and auditory conditioned fear memories.

Mechanisms of PKA-Dependent Potentiation of Kv7.5 Channel Activity in Human Airway Smooth Muscle Cells

β-adrenergic receptor (βAR) activation promotes relaxation of both vascular and airway smooth muscle cells (VSMCs and ASMCs, respectively), though the signaling mechanisms have not been fully elucidated. We previously found that the activity of Kv7.5 voltage-activated potassium channels in VSMCs is robustly enhanced by activation of βARs via a mechanism involving protein kinase A (PKA)-dependent phosphorylation. We also found that enhancement of Kv7 channel activity in ASMCs promotes airway relaxation. Here we provide evidence that Kv7.5 channels are natively expressed in primary cultures of human ASMCs and that they conduct currents which are robustly enhanced in response to activation of the βAR/cyclic adenosine monophosphate (cAMP)/PKA pathway. MIT Scansite software analysis of putative PKA phosphorylation sites on Kv7.5 identified 8 candidate serine or threonine residues. Each residue was individually mutated to an alanine to prevent its phosphorylation and then tested for responses to βAR activation or to stimuli that elevate cAMP levels. Only the mutation of serine 53 (S53A), located on the amino terminus of Kv7.5, significantly reduced the increase in Kv7.5 current in response to these stimuli. A phospho-mimic mutation (S53D) exhibited characteristics of βAR-activated Kv7.5. Serine-to-alanine mutations of 6 putative PKA phosphorylation sites on the Kv7.5 C-terminus, individually or in combination, did not significantly reduce the enhancement of the currents in response to forskolin treatment (to elevate cAMP levels). We conclude that phosphorylation of S53 on the amino terminus of Kv7.5 is essential for PKA-dependent enhancement of channel activity in response to βAR activation in vascular and airway smooth muscle cells.

Whole-Genome Sequencing of Pharmacogenetic Drug Response in Racially Diverse Children with Asthma

RATIONALE

Albuterol, a bronchodilator medication, is the first-line therapy for asthma worldwide. There are significant racial/ethnic differences in albuterol drug response.

OBJECTIVES

To identify genetic variants important for bronchodilator drug response (BDR) in racially diverse children.

METHODS

We performed the first whole-genome sequencing pharmacogenetics study from 1,441 children with asthma from the tails of the BDR distribution to identify genetic association with BDR.

MEASUREMENTS AND MAIN RESULTS

We identified population-specific and shared genetic variants associated with BDR, including genome-wide significant (P < 3.53 × 10-7) and suggestive (P < 7.06 × 10-6) loci near genes previously associated with lung capacity (DNAH5), immunity (NFKB1 and PLCB1), and β-adrenergic signaling (ADAMTS3 and COX18). Functional analyses of the BDR-associated SNP in NFKB1 revealed potential regulatory function in bronchial smooth muscle cells. The SNP is also an expression quantitative trait locus for a neighboring gene, SLC39A8. The lack of other asthma study populations with BDR and whole-genome sequencing data on minority children makes it impossible to perform replication of our rare variant associations. Minority underrepresentation also poses significant challenges to identify age-matched and population-matched cohorts of sufficient sample size for replication of our common variant findings.

CONCLUSIONS

The lack of minority data, despite a collaboration of eight universities and 13 individual laboratories, highlights the urgent need for a dedicated national effort to prioritize diversity in research. Our study expands the understanding of pharmacogenetic analyses in racially/ethnically diverse populations and advances the foundation for precision medicine in at-risk and understudied minority populations.

Pharmacological identification of β-adrenoceptor subtypes mediating isoprenaline-induced relaxation of guinea pig colonic longitudinal smooth muscle

Object We aimed to identify the β-adrenoceptor (β-AR) subtypes involved in isoprenaline-induced relaxation of guinea pig colonic longitudinal smooth muscle using pharmacological and biochemical approaches. Methods Longitudinal smooth muscle was prepared from the male guinea pig ascending colon and contracted with histamine prior to comparing the relaxant responses to three catecholamines (isoprenaline, adrenaline, and noradrenaline). The inhibitory effects of subtype-selective β-AR antagonists on isoprenaline-induced relaxation were then investigated. Results The relaxant potencies of the catecholamines were ranked as: isoprenaline > noradrenaline ≈ adrenaline, whereas the rank order was isoprenaline > noradrenaline > adrenaline in the presence of propranolol (a non-selective β-AR antagonist; 3 × 10^-7 M). Atenolol (a selective β₁-AR antagonist; 3 × 10^-7-10^-6 M) acted as a competitive antagonist of isoprenaline-induced relaxation, and the pA₂ value was calculated to be 6.49 (95% confidence interval: 6.34-6.83). The relaxation to isoprenaline was not affected by ICI-118,551 (a selective β₂-AR antagonist) at 10^-9-10^-8 M, but was competitively antagonized by 10^-7-3 × 10^-7 M, with a pA₂ value of 7.41 (95% confidence interval: 7.18-8.02). In the presence of propranolol (3 × 10^-7 M), the relaxant effect of isoprenaline was competitively antagonized by bupranolol (a non-selective β-AR antagonist), with a pA₂ value of 5.90 (95% confidence interval: 5.73-6.35). Conclusion These findings indicated that the β-AR subtypes involved in isoprenaline-induced relaxation of colonic longitudinal guinea pig muscles are β₁-AR and β₃-AR.

Reduced suppressive effect of β2-adrenoceptor agonist on fibrocyte function in severe asthma

Background

Patients with severe asthma have increased airway remodelling and elevated numbers of circulating fibrocytes with enhanced myofibroblastic differentiation capacity, despite being treated with high doses of corticosteroids, and long acting β₂-adrenergic receptor (AR) agonists (LABAs). We determined the effect of β₂-AR agonists, alone or in combination with corticosteroids, on fibrocyte function.

Methods

Non-adherent non-T cells from peripheral blood mononuclear cells isolated from healthy subjects and patients with non-severe or severe asthma were treated with the β₂-AR agonist, salmeterol, in the presence or absence of the corticosteroid dexamethasone. The number of fibrocytes (collagen I⁺/CD45⁺ cells) and differentiating fibrocytes (α-smooth muscle actin⁺ cells), and the expression of CC chemokine receptor 7 and of β₂-AR were determined using flow cytometry. The role of cyclic adenosine monophosphate (cAMP) was elucidated using the cAMP analogue 8-bromoadenosine 3′,5′-cyclic monophosphate (8-Br-cAMP) and the phosphodiesterase type IV (PDE4) inhibitor, rolipram.

Results

Salmeterol reduced the proliferation, myofibroblastic differentiation and CCR7 expression of fibrocytes from healthy subjects and non-severe asthma patients. Fibrocytes from severe asthma patients had a lower baseline surface β₂-AR expression and were relatively insensitive to salmeterol but not to 8-Br-cAMP or rolipram. Dexamethasone increased β₂-AR expression and enhanced the inhibitory effect of salmeterol on severe asthma fibrocyte differentiation.

Conclusions

Fibrocytes from patients with severe asthma are relatively insensitive to the inhibitory effects of salmeterol, an effect which is reversed by combination with corticosteroids.

Electronic supplementary material

The online version of this article (10.1186/s12931-017-0678-7) contains supplementary material, which is available to authorized users.

Posttranscriptional control of airway inflammation

Acute inflammation in the lungs is a vital protective response, efficiently and swiftly eliminating inciters of tissue injury. However, in respiratory diseases characterized by chronic inflammation, such as chronic obstructive pulmonary disease and asthma, enhanced expression of inflammatory mediators leads to tissue damage and impaired lung function. Although transcription is an essential first step in the induction of proinflammatory genes, tight regulation of inflammation requires more rapid, flexible responses. Increasing evidence shows that such responses are achieved by posttranscriptional mechanisms directly affecting mRNA stability and translation initiation. RNA-binding proteins, microRNAs, and long noncoding RNAs interact with messenger RNA and each other to impact the stability and/or translation of mRNAs implicated in lung inflammation. Recent research has shown that these biological processes play a central role in the pathogenesis of several important pulmonary conditions. This review will highlight several posttranscriptional control mechanisms that influence lung inflammation and the known associations of derangements in these mechanisms with common respiratory diseases. WIREs RNA 2018, 9:e1455. doi: 10.1002/wrna.1455 This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Turnover and Surveillance > Regulation of RNA Stability.

β2-adrenergic receptor-mediated in vitro regulation of human hepatic drug transporter expression by epinephrine

The catecholamine epinephrine is known to repress expression of hepatic drug metabolizing enzymes such as cytochromes P-450. The present study was designed to determine whether epinephrine may also target expression of main hepatic drug transporters, that play a major role in liver detoxification and are commonly coordinately regulated with drug detoxifying enzymes. Treatment of primary human hepatocytes with 10μM epinephrine for 24h repressed mRNA expression of various transporters, such as the sinusoidal influx transporters NTCP, OATP1B1, OATP2B1, OAT2, OAT7 and OCT1 and the efflux transporters MRP2, MRP3 and BSEP, whereas it induced that of MDR1, but failed to alter that of BCRP. Most of these changes in transporter mRNA levels were also found in epinephrine-exposed human highly-differentiated hepatoma HepaRG cells, which additionally exhibited reduced protein expression of OATP2B1 and MRP3, increased expression of P-glycoprotein and decreased transport activity of NTCP, OATPs and OCT1. Epinephrine effects towards transporter mRNA expression in human hepatocytes were next shown to be correlated to those of the selective β2-adrenoreceptor (ADR) agonist fenoterol, of the adenylate cyclase activator forskolin and of the cAMP analogue 8-bromo-cAMP. In addition, the non-selective β-ADR antagonist carazolol and the selective β2-ADR antagonist ICI-118,551, unlike the α-ADR antagonist phentolamine, suppressed epinephrine-mediated repressions of transporter mRNA expression. Taken together, these data indicate that epinephrine regulates in vitro expression of main hepatic drug transporters in a β2-ADR/adenylate cyclase/cAMP-dependent manner. Hepatic drug transport appears therefore as a target of the β2-adrenergic system, which may have to deserve attention for drugs interacting with β2-ADRs.

Bronchopulmonary pharmacokinetics of (R)-salbutamol and (S)-salbutamol enantiomers in pulmonary epithelial lining fluid and lung tissue of horses

AIMS

Salbutamol is usually administered as a racemic mixture but little is known about the enantioselectivity of salbutamol pharmacokinetics in the lung. This study was designed to investigate enantiomer concentrations in lung tissue after inhaled dosing.

METHODS

Horses (n = 12) received racemic salbutamol 1000 μg via inhalation. Enantioselective ultra performance liquid chromatography-tandem mass spectrometry was used to determine salbutamol concentrations in pulmonary epithelial lining fluid (PELF) sampled 2, 5, 10 and 15 min after administration, in central lung (endoscopic bronchial biopsy) and peripheral lung (percutaneous pulmonary biopsy) tissues (at 20 and 25 min respectively), and in plasma samples.

RESULTS

Mean ± 95% confidence interval (CI) yield of PELF was 57 ± 10 mg. Initial mean ± 95%CI (R)- and (S)-salbutamol PELF concentrations were 389 ± 189 ng g^-1 and 378 ± 177 ng g^-1 respectively, and both reduced approximately 50% by 15 min. Mean ± 95%CI central lung levels of drug were higher than peripheral lung tissue for both (R)-salbutamol (875 ± 945 vs. 49.5 ± 12 ng g^-1 ) and (S)-salbutamol (877 ± 955 vs. 50.9 ± 12 ng g^-1 ) respectively. There was no evidence of enantioselectivity in PELF or central lung but minor (~2%) enantioselectivity was observed in the peripheral lung. Enantioselectivity was clearly evident in plasma with (S):(R) ratio of 1.25 and 1.14 for both area under the concentration-time curve (0-25 min) and C_max respectively.

CONCLUSIONS

PELF sampling in horses offers sufficient yield allowing direct detection of drug and, combined with tissue sampling, is a valuable model to investigate bronchopulmonary pharmacokinetics. Salbutamol did not demonstrate enantioselectivity in PELF or central lung tissue uptake following acute dosing, however, enantioselective plasma concentrations were demonstrated, with minor enantioselectivity in the peripheral lung.

Pharmacological Profile of GPD-1116, an Inhibitor of Phosphodiesterase 4

We have previously reported that GPD-1116, an inhibitor of phosphodiesterase (PDE) 4, exhibits anti-inflammatory effects in a model of cigarette smoke-induced emphysema in senescence-accelerated P1 mice. In the present study, we further characterized the pharmacological profile of GPD-1116 in several experiments in vitro and in vivo. GPD-1116 and its metabolite GPD-1133 predominantly inhibited not only human PDE4, but also human PDE1 in vitro. Moreover, GPD-1116 was effective in several disease models in animals, including acute lung injury, chronic obstructive pulmonary disease (COPD), asthma and pulmonary hypertension; the effective doses of GPD-1116 were estimated to be 0.3-2 mg/kg in these models. With regard to undesirable effects known as class effects of PDE4 inhibitors, GPD-1116 showed suppression of gastric emptying in rats and induction of emesis in dogs, but showed no such suppression of rectal temperature in rats, and these side effects of GPD-1116 seemed to be less potent than those of roflumilast. These results suggested that GPD-1116 could be a promising therapeutic agent for the treatment of inflammatory pulmonary diseases. Furthermore, the inhibitory effects of GPD-1116 for PDE1 might be associated with its excellent pharmacological profile. However, the mechanisms through which PDE1 inhibition contributes to these effects should be determined in future studies.

Use of ICS/LABA (extra-fine and non-extra-fine) in elderly asthmatics

Age represents an exclusion criterion in randomized clinical trials designed to test the efficacy and safety of inhaled drugs in asthma. As a consequence, data on efficacy and safety of inhaled corticosteroid (ICS) and long-acting β2 agonist (LABA) combinations in elderly asthmatics are scanty. Older age is associated with an increased proportion of comorbid conditions; in addition, all organ functions undergo a process of senescence, thus reducing their ability to metabolize the agents. Overall, these age-associated conditions may variably, and often unpredictably, affect the metabolism and excretion of respiratory drugs. However, pharmacological treatment of asthma does not follow specific recommendations in the elderly. In the elderly, the ICS/LABA combinations may carry an increased risk of local indesiderable effects, primarily due to the lack of coordination between activation of the device and inhalation, and systemic adverse events, mainly due to the greater amount of active drug that is available because of the age-associated changes in organ functions as well as drug-to-drug and drug-to-concomitant disease interactions. The extra-fine formulations of ICSs/LABAs, which allow for a more favorable drug deposition in the lungs at a reduced dose, may contribute to overcome this issue. This review revises the efficacy and safety of treatment with ICSs/LABAs, focusing on the main pharmacodynamic and pharmacokinetic properties of the drugs and highlighting the potential risks in the elderly asthmatic population.