New bronchodilators

Investigating the Unbinding of Muscarinic Antagonists from the Muscarinic 3 Receptor

Patient symptom relief is often heavily influenced by the residence time of the inhibitor-target complex. For the human muscarinic receptor 3 (hMR3), tiotropium is a long-acting bronchodilator used in conditions such as asthma or chronic obstructive pulmonary disease (COPD). The mechanistic insights into this inhibitor remain unclear; specifically, the elucidation of the main factors determining the unbinding rates could help develop the next generation of antimuscarinic agents. Using our novel unbinding algorithm, we were able to investigate ligand dissociation from hMR3. The unbinding paths of tiotropium and two of its analogues, N-methylscopolamin and homatropine methylbromide, show a consistent qualitative mechanism and allow us to identify the structural bottleneck of the process. Furthermore, our machine learning-based analysis identified key roles of the ECL2/TM5 junction involved in the transition state. Additionally, our results point to relevant changes at the intracellular end of the TM6 helix leading to the ICL3 kinase domain, highlighting the closest residue L482. This residue is located right between two main protein binding sites involved in signal transduction for hMR3's activation and regulation. We also highlight key pharmacophores of tiotropium that play determining roles in the unbinding kinetics and could aid toward drug design and lead optimization.

Therapeutic Approaches for Chronic Obstructive Pulmonary Disease (COPD) Exacerbations

Chronic Obstructive Pulmonary Disease (COPD) is a progressive pulmonary disorder underpinned by poorly reversible airflow resulting from chronic bronchitis or emphysema. The prevalence and mortality of COPD continue to increase. Pharmacotherapy for patients with COPD has included antibiotics, bronchodilators, and anti-inflammatory corticosteroids (but with little success). Oral diseases have long been established as clinical risk factors for developing respiratory diseases. The establishment of a very similar microbiome in the mouth and the lung confirms the oral-lung connection. The aspiration of pathogenic microbes from the oral cavity has been implicated in several respiratory diseases, including pneumonia and chronic obstructive pulmonary disease (COPD). This review focuses on current and future pharmacotherapeutic approaches for COPD exacerbation including antimicrobials, mucoregulators, the use of bronchodilators and anti-inflammatory drugs, modifying epigenetic marks, and modulating dysbiosis of the microbiome.

Elucidation the binding mechanism of Nelumbo nucifera-derived isoquinoline alkaloids as Rho-kinase 1 inhibitors by molecular docking and dynamic simulation

Rho-kinase 1 (ROCK1) is a key molecular target for controlling smooth muscle (SM) contraction in asthma, gastrointestinal disorders, hypertension. Embryos of lotus seed (Nelumbo nucifera) are traditional folk herbs widely used in treating various diseases which are closely related to SM contraction. With the aim of explaining the mechanism of embryos of lotus seed, 27 isoquinoline alkaloids were isolated from the embryos of lotus seed, the inhibitory activity of these alkaloids against ROCK1 were virtual screened via molecular docking and molecular dynamics (MD) simulations. The docking results indicated that 5 bisbenzylisoquinolines (BBIs) and 1 tribenzylisoquinoline (TBI) were potent inhibitors with high binding affinity for both A and B chains of ROCK1 (AcRock and BcRock). The MD results also revealed that neoliensinine (28) was the most potent inhibitor, which was corresponding to the irreversible relaxation effect of neoliensinine on SM. Moreover, through the MD simulation, it also indicated that neoliensinine (28) interacted in its stretched conformation through polar solvation interactions and van der Waal forces. Finally, with the best calculation results, the inhibition effect of neoliensinine (28) on the contraction of vascular smooth muscle cells (VSMCs) and ROCK1 was also confirmed by several biological tests.Communicated by Ramaswamy H. Sarma.

ITRAQ-Based Proteomics Analysis Reveals the Effect of Neoliensinine on KCl-Induced Vascular Smooth Muscle Contraction by Inhibiting Regulatory Light Chain Phosphorylation

Smooth muscle (SM) contraction is one of the important physiological functions of the human body, and SM abnormal contraction will induce many diseases. The phosphorylated regulatory light chains (p-RLC) play a decisive role in SM contraction, and dephosphorylation of p-RLC is an effective way to relax SM. Our previous study showed that the novel benzylisoquinoline alkaloid, neoliensinine (Neo), could relax microvascular SM contracted by KCl hyperpolarization. In this study, mesenteric capillaries isolated from 45 mice were divided into normal tension group (Control), 124 mM KCl induced contraction model group (Model), and KCl and Neo-treatment group (Drug). The dephosphorylation levels of RLC in the three groups were measured. Compared with the model group, the phosphorylation of RLC in the drug group was decreased dramatically as expected, suggesting that the relaxation effect of Neo was caused by downregulating p-RLC of microvessel SM. In order to fully understand its fundamental mechanism, our research focused on the identification of target proteins in mice with KCl-induced contractile mesenteric capillary. Isobaric tags for relative and absolute quantification (ITRAQ) tagging was carried out by nanospray liquid chromatography-tandem mass spectrometry. The results allowed the upregulation of 164 differential abundance proteins (DAPs) among the 3,474 protein abundance disturbances identified from the model/control samples. Further comparison showed that there were 16 DAP convergences associated with vascular SM contraction between the drug/model and the drug/control samples. Among them, two proteins with known function, PLCβ and RhoGEF12, were selected as target proteins of the relaxation effect of Neo. The two selective target DAPs were verified by Western blot at protein level. The results suggested that changes of the two proteins were consistent with that of the iTRAQ results. Our present work reveals that Neo relaxes vascular smooth muscle via inhibition of RLC phosphorylation, and PLCβ and RhoGEF12 may be potential biomarkers for evaluating the effects mediated by Neo.

Toward the Identification of Extra-Oral TAS2R Agonists as Drug Agents for Muscle Relaxation Therapies via Bioinformatics-Aided Screening of Bitter Compounds in Traditional Chinese Medicine

Significant advances have been made in the past decade in mapping the distributions and the physiological functions of extra-oral bitter taste receptors (TAS2Rs) in non-gustatory tissues. In particular, it has been found that TAS2Rs are expressed in various muscle tissues and activation of TAS2Rs can lead to muscle cell relaxation, which suggests that TAS2Rs may be important new targets in muscle relaxation therapy for various muscle-related diseases. So far, however, there is a lack of potent extra-oral TAS2R agonists that can be used as novel drug agents in muscle relaxation therapies. Interestingly, traditional Chinese medicine (TCM) often characterizes a drug’s property in terms of five distinct flavors (bitter, sweet, sour, salty, and pungent) according to its taste and function, and commonly regards “bitterness” as an intrinsic property of “good medicine.” In addition, many bitter flavored TCM are known in practice to cause muscle relaxation after long term use, and in lab experiments the compounds identified from some bitter flavored TCM do activate TAS2Rs and thus relax muscle cells. Therefore, it is highly possible to discover very useful extra-oral TAS2R agonists for muscle relaxation therapies among the abundant bitter compounds used in bitter flavored TCM. With this perspective, we reviewed in literature the distribution of TAS2Rs in different muscle systems with a focus on the map of bitter flavored TCM which can regulate muscle contractility and related functional chemical components. We also reviewed the recently established databases of TCM chemical components and the bioinformatics software which can be used for high-throughput screening and data mining of the chemical components associated with bitter flavored TCM. All together, we aim to present a knowledge-based approach and technological platform for identification or discovery of extra-oral TAS2R agonists that can be used as novel drug agents for muscle relaxation therapies through screening and evaluation of chemical compounds used in bitter flavored TCM.

Early management of COPD: where are we now and where do we go from here? A Delphi consensus project

PURPOSE

There is a lack of consensus on the most appropriate early diagnostic strategy, criteria for early access to treatment and follow-up approach for patients with COPD.

MATERIALS AND METHODS

A Delphi consensus project investigated the early management of COPD. We formulated two questionnaires for completion by pneumologists in Italy.

RESULTS

A total of 207 specialists completed questionnaire 1 and 184 of them questionnaire 2, between November 2016 and October 2017. Early diagnosis of COPD was considered uncommon for 93.2% of the expert panel. Regardless of the definition of "early diagnosis" - a diagnosis made before the clinical manifestation of the disease for most responders (60.4%) - experts were confident of the positive effects of early disease management, which they consider is effective in modifying the natural history of the disease. Lack of awareness of the disease was considered the first limiting factor to early COPD management for 78% of respondents. The most effective steps to reduce functional decline were considered to be smoking cessation, followed by long-acting β2-agonist (LABA)/long-acting muscarinic antagonist (LAMA), LAMA, LABA, and finally inhaled corticosteroid/LABA (P<0.01 for each paired comparison). Specialists considered it "inappropriate" for general practitioners to perform both the early diagnosis and therapy of COPD without the involvement of a specialist.

CONCLUSION

Early management of COPD is uncommon, and although data on the effects of early disease management on long-term outcomes are limited, Italian experts are confident of the clinical efficacy of this approach.

Prevention of acute exacerbations of COPD: American College of Chest Physicians and Canadian Thoracic Society Guideline

BACKGROUND

COPD is a major cause of morbidity and mortality in the United States as well as throughout the rest of the world. An exacerbation of COPD (periodic escalations of symptoms of cough, dyspnea, and sputum production) is a major contributor to worsening lung function, impairment in quality of life, need for urgent care or hospitalization, and cost of care in COPD. Research conducted over the past decade has contributed much to our current understanding of the pathogenesis and treatment of COPD. Additionally, an evolving literature has accumulated about the prevention of acute exacerbations.

METHODS

In recognition of the importance of preventing exacerbations in patients with COPD, the American College of Chest Physicians (CHEST) and Canadian Thoracic Society (CTS) joint evidence-based guideline (AECOPD Guideline) was developed to provide a practical, clinically useful document to describe the current state of knowledge regarding the prevention of acute exacerbations according to major categories of prevention therapies. Three key clinical questions developed using the PICO (population, intervention, comparator, and outcome) format addressed the prevention of acute exacerbations of COPD: nonpharmacologic therapies, inhaled therapies, and oral therapies. We used recognized document evaluation tools to assess and choose the most appropriate studies and to extract meaningful data and grade the level of evidence to support the recommendations in each PICO question in a balanced and unbiased fashion.

RESULTS

The AECOPD Guideline is unique not only for its topic, the prevention of acute exacerbations of COPD, but also for the first-in-kind partnership between two of the largest thoracic societies in North America. The CHEST Guidelines Oversight Committee in partnership with the CTS COPD Clinical Assembly launched this project with the objective that a systematic review and critical evaluation of the published literature by clinical experts and researchers in the field of COPD would lead to a series of recommendations to assist clinicians in their management of the patient with COPD.

CONCLUSIONS

This guideline is unique because it provides an up-to-date, rigorous, evidence-based analysis of current randomized controlled trial data regarding the prevention of COPD exacerbations.

Airway smooth muscle: a potential target for asthma therapy

PURPOSE OF REVIEW

Asthma is a major public health problem that afflicts nearly one in 20 people worldwide. Despite available treatments, asthma symptoms remain poorly controlled in a significant minority of asthma patients, especially those with severe disease. Accordingly, much ongoing effort has been directed at developing new therapeutic strategies; these efforts are described in detail below.

RECENT FINDINGS

Although mucus hypersecretion is an important component of asthma pathobiology, the primary mechanism of morbidity and mortality in asthma is excessive narrowing of the airway. The key end- effector of excessive airway narrowing is airway smooth muscle (ASM) contraction; overcoming ASM contraction is therefore a prominent therapeutic strategy. Here, we review exciting new advances aimed at ASM relaxation.

SUMMARY

Exciting advances in ASM biology have identified new therapeutic targets for the prevention or reversal of bronchoconstriction in asthma.

Advances in targeting cyclic nucleotide phosphodiesterases

Cyclic nucleotide phosphodiesterases (PDEs) catalyse the hydrolysis of cyclic AMP and cyclic GMP, thereby regulating the intracellular concentrations of these cyclic nucleotides, their signalling pathways and, consequently, myriad biological responses in health and disease. Currently, a small number of PDE inhibitors are used clinically for treating the pathophysiological dysregulation of cyclic nucleotide signalling in several disorders, including erectile dysfunction, pulmonary hypertension, acute refractory cardiac failure, intermittent claudication and chronic obstructive pulmonary disease. However, pharmaceutical interest in PDEs has been reignited by the increasing understanding of the roles of individual PDEs in regulating the subcellular compartmentalization of specific cyclic nucleotide signalling pathways, by the structure-based design of novel specific inhibitors and by the development of more sophisticated strategies to target individual PDE variants.

Sports doping: emerging designer and therapeutic β2-agonists

Beta2-adrenergic agonists, or β2-agonists, are considered essential bronchodilator drugs in the treatment of bronchial asthma, both as symptom-relievers and, in combination with inhaled corticosteroids, as disease-controllers. The use of β2-agonists is prohibited in sports by the World Anti-Doping Agency (WADA) due to claimed anabolic effects, and also, is prohibited as growth promoters in cattle fattening in the European Union. This paper reviews the last seven-year (2006-2012) literature concerning the development of novel β2-agonists molecules either by modifying the molecule of known β2-agonists or by introducing moieties producing indole-, adamantyl- or phenyl urea derivatives. New emerging β2-agonists molecules for future therapeutic use are also presented, intending to emphasize their potential use for doping purposes or as growth promoters in the near future.

The clinical and economic burden of chronic obstructive pulmonary disease in the USA

Chronic obstructive pulmonary disease (COPD) is the third most common cause of death in the USA. In 2010, the cost of COPD in the USA was projected to be approximately US$50 billion, which includes $20 billion in indirect costs and $30 billion in direct health care expenditures. These costs can be expected to continue to rise with this progressive disease. Costs increase with increasing severity of disease, and hospital stays account for the majority of these costs. Patients are diagnosed with COPD following a multifactorial assessment that includes spirometry, clinical presentation, symptomatology, and risk factors. Smoking cessation interventions are the most influential factor in COPD management. The primary goal of chronic COPD management is stabilization of chronic disease and prevention of acute exacerbations. Bronchodilators are the mainstay of COPD therapy. Patients with few symptoms and low exacerbation risk should be treated with a short-acting bronchodilator as needed for breathlessness. Progression of symptoms, as well as possible decline in forced expiratory volume in the first second of expiration (FEV1), warrant the use of long-acting bronchodilators. For patients with frequent exacerbations with or without consistent symptoms, inhaled corticosteroids should be considered in addition to a long-acting beta2-agonist (LABA) or long-acting muscarinic antagonist (LAMA) and may even consist of "triple therapy" with all three agents with more severe disease. Phosphodiesterase-4 inhibitors may be an option in patients with frequent exacerbations and symptoms of chronic bronchitis. In addition to a variety of novel ultra-LABAs, LAMAs and combination bronchodilator and inhaled corticosteroid (ICS) therapies, other bronchodilators with a variety of mechanisms are also being considered, to expand therapeutic options for the treatment of COPD. With more than 50 new medications in the pipeline for the treatment of COPD, optimal management will continue to evolve and grow more complex as benefits of therapy are balanced with the limitations and needs of each patient.

Emerging targets for novel therapy of asthma

Significant advances in understanding the cell and molecular biology of inflammation and airway smooth muscle (ASM) contractility have identified several potential novel targets for therapies of asthma. New agents targeting G-protein coupled receptors (GPCRs) including bitter taste receptors (TAS2R) agonists and prostaglandin EP4 receptor agonists elicit ASM relaxation. The cAMP/PKA pathway continues to be a promising drug target with the emergence of new PDE inhibitors and a novel PKA target protein, HSP20, which mediates smooth muscle relaxation via actin depolymerization. Smooth muscle relaxation can also be elicited by inhibitors of the RhoA/Rho kinase pathway via inhibition of myosin light chain phosphorylation and actin depolymerization. Targeting epigenetic processes that control chromatin remodeling and RNA-induced gene silencing in airway cells also holds great potential for novel asthma therapy. Further investigation may identify agents that inhibit smooth muscle contraction and/or restrain or reverse obstructive remodeling of the airways.

Emerging Therapeutic Options for the Management of COPD

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death worldwide and is projected to be the third by 2020. COPD is characterized by chronic airflow limitation caused by airway inflammation and parenchymal destruction that is usually progressive. Inhaled bronchodilators continue to be the mainstay of the current management of COPD. Safety and efficacy data of the recently approved medications including aclidinium, glycopyrronium, roflumilast, and indacaterol are reviewed here.