Effect of cilomilast (Ariflo) on TNF-alpha, IL-8, and GM-CSF release by airway cells of patients with COPD

Astaxanthin attenuates cigarette smoking-induced oxidative stress and inflammation in a sirtuin 1-dependent manner

Oxidative stress and chronic inflammation play key roles in the pathogenesis of chronic obstructive pulmonary disease (COPD). Astaxanthin (AXT) is a keto-carotenoid with a variety of biological functions, including antioxidant and anti-inflammatory effects This study aimed to explore the protective role and underlying mechanism of AXT in the pathogenesis of COPD. In this study, we found AXT alleviated pulmonary emphysema in a CS-exposed mouse model and regulated the expression of MMP-9/TIMP-1. And, AXT attenuates CSE-induced small airway fibrosis. Meanwhile, AXT inhibited Nrf2-modulated oxidative stress and the p65 NF-κB-regulated inflammatory pathway in both the mouse model and CSE-treated HBE cells. Mechanistically, AXT could directly bind to SIRT1 (the binding energy of the complex was -8.8 kcal/mol) and regulate the deacetylation activity of SIRT1. Finally, by activating SIRT1 deacetylation, AXT deacetylated Nrf2 and contributed to its action of reducing oxidative stress by generating antioxidant enzymes, and inhibiting p65 NF-κB transcriptional activity to suppress the inflammatory response. Our results show that treatment with AXT significantly reverses the oxidative stress and inflammation induced by cigarette smoke both in vivo and in vitro in a sirtuin 1-dependent manner.

Donor-to-donor variability of a human three-dimensional bronchial epithelial model: A case study of cigarette smoke exposure

Three-dimensional (3D) cultured primary cells are used to predict the toxicity of substances towards humans because these 3D cultures closely mimic the physiological architecture of tissues. Nonetheless, it is important to consider primary-cell-specific variability for endpoint selection and appropriate evaluation of toxicity because donor-dependent characteristics may be retained even in in vitro cell cultures. In this report, 3D differentiated bronchial epithelial cells from three donors were used to investigate donor-to-donor variability, with an aqueous extract of cigarette smoke (CS) used as the test substance. Ciliary function, cytokine secretion, and histopathology, which are affected by CS, were examined, and transcriptomic analysis was also performed. The results revealed that interleukin-8 secretion and oxidative stress-related gene expression were consistently altered for all donors; however, their amplitudes varied. Moreover, one of the donors showed unique responses to CS, suggesting that this donor was an outlier. This donor showed intrinsic differences in histology, cytokine secretion, and gene expression profile. Such donors may help evaluate potential toxicological concerns and aid our understanding of disease pathogenesis. Conversely, these donors may confound toxicological assessment and endpoint selection. Fit-for-purpose handling of inter-donor variability is warranted.

Cyclic nucleotide phosphodiesterase inhibitors as therapeutic interventions for cystic fibrosis

Cystic Fibrosis (CF) lung disease results from mutations in the CFTR anion channel that reduce anion and fluid secretion by airway epithelia. Impaired secretion compromises airway innate defence mechanisms and leads to bacterial colonization, excessive inflammation and tissue damage; thus, restoration of CFTR function is the goal of many CF therapies. CFTR channels are activated by cyclic nucleotide-dependent protein kinases. The second messengers 3'5'-cAMP and 3'5'-cGMP are hydrolysed by a large family of cyclic nucleotide phosphodiesterases that provide subcellular spatial and temporal control of cyclic nucleotide-dependent signalling. Selective inhibition of these enzymes elevates cyclic nucleotide levels, leading to activation of CFTR and other downstream effectors. Here we examine members of the PDE family that are likely to regulate CFTR-dependent ion and fluid secretion in the airways and discuss other actions of PDE inhibitors that can influence cyclic nucleotide-regulated mucociliary transport, inflammation and bronchodilation. Finally, we review PDE inhibitors and the potential benefits they could provide as CF therapeutics.

Clinical Relevance of the Anti-inflammatory Effects of Roflumilast on Human Bronchus: Potentiation by a Long-Acting Beta-2-Agonist

Background: Roflumilast is an option for treating patients with severe COPD and frequent exacerbations despite optimal therapy with inhaled drugs. The present study focused on whether the phosphodiesterase (PDE) 4 inhibitor roflumilast and its active metabolite roflumilast N-oxide affect the release of tumor necrosis factor (TNF)-α and chemokines by lipopolysaccharide (LPS)-stimulated human bronchial explants. We also investigated the interactions between roflumilast, roflumilast N-oxide and the β₂-agonist formoterol with regard to cytokine release by the bronchial preparations.

Methods: Bronchial explants from resected lungs were incubated with roflumilast, roflumilast N-oxide and/or formoterol and then stimulated with LPS. An ELISA was used to measure levels of TNF-α and chemokines in the culture supernatants.

Results: At a clinically relevant concentration (1 nM), roflumilast N-oxide and roflumilast consistently reduced the release of TNF-α, CCL2, CCL3, CCL4, CCL5 and CXCL9 (but not CXCL1, CXCL5, CXCL8 and IL-6) from human bronchial explants. Formoterol alone decreased the release of TNF-α, CCL2, and CCL3. The combination of formoterol with roflumilast (1 nM) was more potent than roflumilast alone for inhibiting the LPS-induced release of TNF-α, CCL2, CCL3, CCL4, and CXCL9 by the bronchial explants.

Conclusions: At a clinically relevant concentration, roflumilast N-oxide and its parent compound, roflumilast, reduced the LPS-induced production of TNF-α and chemokines involved in monocyte and T-cell recruitment but did not alter the release of chemokines involved in neutrophil recruitment. The combination of formoterol with roflumilast enhanced the individual drugs’ anti-inflammatory effects.

The Phosphodiesterase Inhibitor Ensifentrine Reduces Production of Proinflammatory Mediators in Well Differentiated Bronchial Epithelial Cells by Inhibiting PDE4

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel that impair airway salt and fluid secretion. Excessive release of proinflammatory cytokines and chemokines by CF bronchial epithelium during airway infection leads to chronic inflammation and a slow decline in lung function; thus, there is much interest in finding safe and effective treatments that reduce inflammation in CF. We showed previously that the cyclic nucleotide phosphodiesterase (PDE) inhibitor ensifentrine (RPL554; Verona Pharma) stimulates the channel function of CFTR mutants with abnormal gating and also those with defective trafficking that are partially rescued using a clinically approved corrector drug. PDE inhibitors also have known anti-inflammatory effects; therefore, we examined whether ensifentrine alters the production of proinflammatory cytokines in CF bronchial epithelial cells. Ensifentrine reduced the production of monocyte chemoattractant protein-1 and granulocyte monocyte colony-stimulating factor (GM-CSF) during challenge with interleukin-1β Comparing the effect of ensifentrine with milrinone and roflumilast, selective PDE3 and PDE4 inhibitors, respectively, demonstrated that the anti-inflammatory effect of ensifentrine was mainly due to inhibition of PDE4. Beneficial modulation of GM-CSF was further enhanced when ensifentrine was combined with low concentrations of the β ₂-adrenergic agonist isoproterenol or the corticosteroid dexamethasone. The results indicate that ensifentrine may have beneficial anti-inflammatory effects in CF airways particularly when used in combination with β ₂-adrenergic agonists or corticosteroids. SIGNIFICANCE STATEMENT: Airway inflammation that is disproportionate to the burden of chronic airway infection causes much of the pathology in the cystic fibrosis (CF) lung. We show here that ensifentrine beneficially modulates the release of proinflammatory factors in well differentiated CF bronchial epithelial cells that is further enhanced when combined with β₂-adrenergic agonists or low-concentration corticosteroids. The results encourage further clinical testing of ensifentrine, alone and in combination with β₂-adrenergic agonists or low-concentration corticosteroids, as a novel anti-inflammatory therapy for CF.

Cytokine profile in the sputum of subjects with post-tuberculosis airflow obstruction and in those with tobacco related chronic obstructive pulmonary disease

BACKGROUND

Previous studies have shown that tuberculosis (TB) is a risk factor for chronic airflow limitation. Chronic obstructive pulmonary disease (COPD) is recognized as the result of chronic inflammation, usually related to noxious particles. Post-TB airflow obstruction and tobacco-related COPD have the same functional pathway characterized by persistent airflow limitation. We sought to compare the profile of 29 cytokines in the sputum of subjects with post-TB airflow obstruction and those with COPD related to tobacco.

RESULTS

The forced expiratory volume in the first second (FEV1) and forced expiratory volume/forced vital capacity (FEV/FVC) ratio were lower in the COPD patients with the history of smoking compared to the post-TB airflow obstruction subgroup. The stages of the disease were more advanced in COPD / tobacco patients. Among the cytokines, IL-1α, IL-1β, MIP-1β, sCD40L and VEGF levels were higher in COPD patients, compared to the controls with p values ​​of 0.003, 0.0001, 0.03, 0.0001 and 0.02 respectively. When the two COPD subgroups were compared, IL-1α, IL-6, TNF-α and IL-8 levels were higher in the COPD patients with the history of tobacco compared to the COPD patients with the history of TB with p-values ​​of 0.031, 0.05, 0.021 and 0.016, respectively.

CONCLUSION

COPD related to tobacco is more severe than post-TB airflow obstruction. The pathogenesis of post-TB airflow obstruction appears to involve the cytokines IL-1RA, IL-1α, IL-1β, IL-17, GRO and sCD40L, while COPD related to tobacco involves more cytokines.

Non-cytotoxic doses of shikonin inhibit lipopolysaccharide-induced TNF-α expression via activation of the AMP-activated protein kinase signaling pathway

Shikonin has been reported to exhibit a wide variety of medical functions. However, the strong non-selective cytotoxicity of shikonin can restrict its clinical application. The aim of the present study was to investigate the effects of shikonin at non-cytotoxic doses on the pro-inflammation functions of monocytes and macrophages. The present results suggested that the non-cytotoxic doses of shikonin effectively inhibited lipopolysaccharide (LPS)-induced reactive oxygen species production, NF-κB activation and TNF-α expression in RAW 264.7 mouse macrophages via AMP-activated protein kinase (AMPK) signaling pathway. In addition, the non-cytotoxic doses of shikonin downregulated LPS-induced TNF-α expression via AMPK signaling activation in primary murine bone marrow-derived macrophages, and also in monocytes cultured ex vivo from patients with chronic obstructive pulmonary disease (COPD). The present in vivo results indicated that the low-toxic dose of shikonin suppressed LPS-induced endotoxin shock and TNF-α expression in mice. Collectively, the present results may provide clinical and translational relevance for treating COPD and other TNF-α-related inflammatory disorders.

Chronic Obstructive Pulmonary Disease: A Palliative Medicine Review of the Disease, Its Therapies, and Drug Interactions

Despite significant advances in treatment, chronic obstructive pulmonary disease (COPD) remains a chronic and progressive disease that frequently leads to premature mortality. COPD is associated with a constellation of significant symptoms, including dyspnea, cough, wheezing, pain, fatigue, anxiety, depression, and insomnia, and is associated with increased morbidity. Palliative care is appropriate to support these patients. However, historically, palliative care has focused on supporting patients with malignant disease, rather than progressive chronic diseases such as COPD. Therapies for COPD often result in functional and symptomatic improvements, including health-related quality of life (HRQL), and palliative care may further improve symptoms and HRQL. Provision of usual palliative care therapies for this patient population requires understanding the pathogenesis of COPD and common disease-targeted pharmacotherapies, as well as an approach to balancing life-prolonging and HRQL care strategies. This review describes COPD and current targeted therapies and their effects on symptoms, exercise tolerance, HRQL, and survival. It is important to note that medications commonly used for symptom management in palliative care can interact with COPD medications resulting in increased risk of adverse effects, enhanced toxicity, or changes in clearance of medications. To address this, we review pharmacologic interactions with and precautions related to use of COPD therapies in conjunction with commonly used palliative care medications.

Trans-4,4'-dihydroxystilbene ameliorates cigarette smoke-induced progression of chronic obstructive pulmonary disease via inhibiting oxidative stress and inflammatory response

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease resulted from airflow obstructions, and there is a driving requirement for novel and effective preventive and therapeutic agents of COPD. Nuclear factor-erythroid 2-related factor 2 (Nrf2) has been regarded to be a promising therapeutic target for COPD. Resveratrol is a natural Nrf2 activator with antioxidant and anti-inflammatory properties, however, its application is limited by its relative low efficiency and poor bioavailability. Herein, based on the skeleton of resveratrol, trans-4,4'-dihydroxystilbene (DHS) has been firstly identified to be an Nrf2 activator, which is more potent than the well-known sulforaphane (SF) and resveratrol. Our results indicate that DHS blocks Nrf2 ubiquitylation through specifically reacting with Cys151 cysteine in Keap1 protein to activate Nrf2-regulated defensive response, and thus enhances intracellular antioxidant capability. Furthermore, DHS relieves lipopolysaccharide (LPS)-stimulated inflammatory response via inhibition of NF-κB. Importantly, DHS significantly ameliorates pathological alterations (e.g. infiltration of leukocytes and fibrosis), downregulates the levels of oxidant biomarkers malondialdehyde (MDA) and 8-oxo-7,8-dihydro-2'-deoxyguanosin (8-oxo-dG), and inhibits the overproductions of inflammatory mediators [e.g. tumor necrosis factor α (TNF-α), cyclooxygenase-2 (COX-2), and matrix metalloproteinase-9 (MMP-9)] in a cigarette smoke (CS)-induced pulmonary impairment mice model. Taken together, this study demonstrates that DHS attenuates the CS-induced pulmonary impairments through inhibitions of oxidative stress and inflammatory response targeting Nrf2 and NF-κB in vitro and in vivo, and could be developed into a preventive agent against pulmonary impairments induced by CS.

Preterm Birth, Inflammation and Infection: New Alternative Strategies for their Prevention

BACKGROUND

Worldwide, the progress in reducing neonatal mortality has been very slow. The rate of preterm birth has increased over the last 20 years in low-income and middle-income countries. Its association with increased mortality and morbidity is based on experimental studies and neonatal outcomes from countries with socioeconomic differences, which have considered implementing alternative healthcare strategies to prevent and reduce preterm births.

METHODS

Currently, there is no widely effective strategy to prevent preterm birth. Pharmacological therapies are directed at inhibiting myometrial contractions to prolong parturition. Some drugs, medicinal plants and microorganisms possess myorelaxant, anti-inflammatory and immunomodulatory properties that have proved useful in preventing preterm birth associated with inflammation and infection.

RESULTS

This review focuses on the existing literature regarding the use of different drugs, medicinal plants, and microorganisms that show promising benefits for the prevention of preterm birth associated with inflammation and infection. New alternative strategies involving the use of PDE-4 inhibitors, medicinal plants and probiotics could have a great impact on improving prenatal and neonatal outcomes and give babies the best start in life, ensuring lifelong health benefits.

CONCLUSION

Despite promising results from well-documented cases, only a small number of these alternative strategies have been studied in clinical trials. The development of new drugs and the use of medicinal plants and probiotics for the treatment and/or prevention of preterm birth is an area of growing interest due to their potential therapeutic benefits in the field of gynecology and obstetrics.

Phosphodiesterases as therapeutic targets for respiratory diseases

Chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and asthma, affect millions of people all over the world. Cyclic adenosine monophosphate (cAMP) which is one of the most important second messengers, plays a vital role in relaxing airway smooth muscles and suppressing inflammation. Given its vast role in regulating intracellular responses, cAMP provides an attractive pharmaceutical target in the treatment of chronic respiratory diseases. Phosphodiesterases (PDEs) are enzymes that hydrolyze cyclic nucleotides and help control cyclic nucleotide signals in a compartmentalized manner. Currently, the selective PDE4 inhibitor, roflumilast, is used as an add-on treatment for patients with severe COPD associated with bronchitis and a history of frequent exacerbations. In addition, other novel PDE inhibitors are in different phases of clinical trials. The current review provides an overview of the regulation of various PDEs and the potential application of selective PDE inhibitors in the treatment of COPD and asthma. The possibility to combine various PDE inhibitors as a way to increase their therapeutic effectiveness is also emphasized.

Oxidative stress responses in human bronchial epithelial cells exposed to cigarette smoke and vapor from tobacco- and nicotine-containing products

The use of novel tobacco- and nicotine-containing vapor products that do not combust tobacco leaves is on the rise worldwide. The emissions of these products typically contain lower numbers and levels of potentially harmful chemicals compared with conventional cigarette smoke. These vapor products may therefore elicit fewer adverse biological effects. We compared the effects of emissions from different types of such products, i.e., our proprietary novel tobacco vapor product (NTV), a commercially available heat-not-burn tobacco product (HnB), and e-cigarette (E-CIG), and a combustible cigarette in a human bronchial epithelial cell line. The aqueous extract (AqE) of the test product was prepared by bubbling the produced aerosol into medium. Cells were exposed to the AqEs of test products, and then glutathione oxidation, Nrf2 activation, and secretion of IL-8 and GM-CSF were examined. We found that all endpoints were similarly perturbed by exposure to each AqE, but the effective dose ranges were different between cigarette smoke and the tobacco- and nicotine-containing vapors. These results demonstrate that the employed assays detect differences between product exposures, and thus may be useful to understand the relative potential biological effects of tobacco- and nicotine-containing products.

The evaluation of inflammatory, anti-inflammatory and regulatory factors contributing to the pathogenesis of COPD in airways

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a progressive chronic disease leading to obstructive lung airways and airflow limitations. The background of COPD is extensive cytopathology and histopathology orchestrated by mostly chronic inflammation with the local release of inflammatory, anti-inflammatory and regulatory mediators, as well as further remodeling and shaping of local architecture. Inflammatory mechanisms are provided by complex intercellular signalling networks and regulation of locally occurring immune responses.

MATERIAL AND METHODS

In this study, lung tissue specimens obtained from 33 COPD patients and 49 control patients were analysed. Tissue samples were examined by hematoxylin and eosin staining. Immunoreactive cells positive for interleukin (IL)-1α (IL-1α), IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, and tumour necrosis factor-α (TNF-α) were detected by an immunohistochemistry (IHC) method.

RESULTS

We evaluated overall higher numbers of IL-7, IL-8 and IL-10 (mostly from few (0/+) to almost abundance (++++)) and overall less numbers of IL-1α and IL-6 (mostly from no positive (0) to numerous to abundance (+++/++++)) immunoreactive cells in airway epithelium and connective tissue of COPD affected lung. Furthermore, we evaluated statistically significant (P < 0.05) higher numbers of immunoreactive cells located in control group airway epithelium for IL-4, IL-6, IL-7, IL-10, and IL-12 compared to mucosal and submucosal connective tissue. Moreover, in COPD group airway epithelium for IL-1α, IL-4, IL-6, IL-7, IL-8, and IL-10. We found no statistically significant difference between the numbers of IL-12 and TNF-α immunoreactive cells in airway epithelium and connective tissue of COPD affected lung. In comparison with the control group, we found statistically significant (P < 0.05) higher numbers of immunoreactive cells positive for all examined markers in COPD group.

CONCLUSIONS

Increased numbers of IL-1α, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, and TNF-α immunoreactive cells highlight the local significance of these markers in COPD pathogenesis. Moreover, the pattern with dominance of immunoreactive cells in COPD affected airway epithelium over connective tissue is highlighting the essentials of epithelium in inflammatory signalling.

Chronic obstructive pulmonary disease (COPD): neutrophils, macrophages and lymphocytes in patients with anterior tuberculosis compared to tobacco related COPD

OBJECTIVE

The inflammatory profile of chronic obstructive pulmonary disease (COPD) related to tobacco is known in certain studies while that of the post tuberculosis form is not yet known. This study aimed to evaluate the levels of neutrophils, macrophages and lymphocytes cells in sputum of COPD patients with history of smoking or anterior tuberculosis. Enumeration of cells in samples was analyzed using standard microscopy.

RESULTS

We enrolled 92 participants, 46 (50%) were COPD subjects comprising 22 (47.83%) smokers and 24 (52.17%) with anterior tuberculosis while 46 (50%) healthy persons constituted the control group. The levels of neutrophils, lymphocytes and monocytes were statistically higher in COPD patients compared to the control group with p-values of 0.0001 respectively. Neutrophils levels were higher in COPD patients with history of tobacco than in COPD patients with anterior tuberculosis with a mean rate of 4.72 × 106/ml and 2.48 × 106/ml respectively (p = 0.04). The monocytes and lymphocytes levels were not statistically different between the two sub-groups of COPD patients with p-value of 0.052 and 0.91 respectively. Neutrophils are the only inflammatory cells that were significantly higher in COPD patients with history of smoking as compared to COPD patients with anterior tuberculosis.

miR-135b-5p inhibits LPS-induced TNFα production via silencing AMPK phosphatase Ppm1e

AMPK activation in monocytes could suppress lipopolysaccharide (LPS)-induced tissue-damaging TNFa production. We are set to provoke AMPK activation via microRNA (“miRNA”) downregulating its phosphatase Ppm1e. In human U937 and THP-1 monocytes, forced expression of microRNA-135b-5p (“miR-135b-5p”) downregulated Ppm1e and activated AMPK signaling. Further, LPS-induced TNFα production in above cells was dramatically attenuated. Ppm1e shRNA knockdown in U937 cells also activated AMPK and inhibited TNFα production by LPS. AMPK activation is required for miR-135b-induced actions in monocytes, AMPKα shRNA knockdown or T172A dominant negative mutation almost abolished miR-135b-5p's suppression on LPS-induced TNFα production. Significantly, miR-135b-5p inhibited LPS-induced reactive oxygen species (ROS) production, NFκB activation and TNFα mRNA expression in human macrophages. AMPKα knockdown or mutation again abolished above actions by miR-135b-5p. We conclude that miR-135b-5p expression downregulates Ppm1e to activate AMPK signaling, which inhibits LPS-induced TNFα production via suppressing ROS production and NFκB activation.

Epac Function and cAMP Scaffolds in the Heart and Lung

Evidence collected over the last ten years indicates that Epac and cAMP scaffold proteins play a critical role in integrating and transducing multiple signaling pathways at the basis of cardiac and lung physiopathology. Some of the deleterious effects of Epac, such as cardiomyocyte hypertrophy and arrhythmia, initially described in vitro, have been confirmed in genetically modified mice for Epac1 and Epac2. Similar recent findings have been collected in the lung. The following sections will describe how Epac and cAMP signalosomes in different subcellular compartments may contribute to cardiac and lung diseases.

Fluoxetine, an Antidepressant Drug, Inhibited Cigarette Smoke-Induced Pulmonary Inflammation and Apoptosis in Rats

The present study was designed to evaluate the anti-inflammatory effect of fluoxetine (Flu) against cigarette smoke (CS)-induced chronic obstructive pulmonary disease (COPD) in rats. Forty male Sprague-Dawley (SD) rats were randomly assigned to five groups: control group, CS group, dexamethasone (2 mg/kg) group, and flu (2 mg/kg). H&E staining demonstrated that Flu inhibited CS-induced pathological injury. In addition, Flu could restore the levels of superoxide dismutase (SOD) and malondialdehyde (MDA) in serum. Flu also inhibited the levels of cytokines including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β). Furthermore, flu significantly inhibited the protein levels of TLR/NF-κB and apoptosis pathway in CS-induced rats. Our findings suggested that flu might effectively ameliorate the progression of COPD via inflammation and apoptosis pathway in rats.

Efficacy of Rhesus Theta-Defensin-1 in Experimental Models of Pseudomonas aeruginosa Lung Infection and Inflammation

Chronic airway infection and inflammation contribute to the progressive loss of lung function and shortened survival of patients with cystic fibrosis (CF). Rhesus theta defensin-1 (RTD-1) is a macrocyclic host defense peptide with antimicrobial and immunomodulatory activities. Combined with favorable preclinical safety and peptide stability data, RTD-1 warrants investigation to determine its therapeutic potential for treatment of CF lung disease. We sought to evaluate the therapeutic potential of RTD-1 for CF airway infection and inflammation using in vitro, ex vivo, and in vivo models. We evaluated RTD-1's effects on basal and Pseudomonas aeruginosa-induced inflammation in CF sputum leukocytes and CF bronchial epithelial cells. Peptide stability was evaluated by incubation with CF sputum. Airway pharmacokinetics, safety, and tolerance studies were performed in naive mice. Aerosolized RTD-1 treatment effects were assessed by analyzing lung bacterial burdens and airway inflammation using an established model of chronic P. aeruginosa endobronchial infection in CF (ΔF508) mice. RTD-1 directly reduces metalloprotease activity, as well as inflammatory cytokine secretion from CF airway leukocyte and bronchial epithelial cells. Intrapulmonary safety, tolerability, and stability data support the aerosol administration route. RTD-1 reduced the bacterial lung burden, airway neutrophils, and inflammatory cytokines in CF mice with chronic P. aeruginosa lung infection. Collectively, these studies support further development of RTD-1 for treatment of CF airway disease.

A novel AMPK activator hernandezine inhibits LPS-induced TNFα production

Here, we found that hernandezine, a novel AMPK activator, inhibited LPS-induced TNFα expression/production in human macrophage cells (THP-1 and U937 lines). Activation of AMPK is required for hernandezine-induced anti-LPS response. AMPKα shRNA or dominant negative mutation (T172A) blocked hernandezine-induced AMPK activation, which almost completely reversed anti-LPS activity by hernandezine. Exogenous expression of the constitutively activate AMPKα (T172D, caAMPKα) also suppressed TNFα production by LPS. Remarkably, hernandezine was unable to further inhibit LPS-mediated TNFα production in caAMPKα-expressing cells. Hernandezine inhibited LPS-induced reactive oxygen species (ROS) production and nuclear factor kappa B (NFκB) activation. Treatment of hernandezine in ex-vivo cultured primary human peripheral blood mononuclear cells (PBMCs) also largely attenuated LPS-induced TNFα production. Together, we conclude that AMPK activation by hernandezine inhibits LPS-induced TNFα production in macrophages/monocytes.

RETRACTED: Salidroside alleviates cigarette smoke-induced COPD in mice

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the authors, who have informed the Editor-in-Chief that they had not obtained the necessary ethical approval for the animal studies before performing the experiments. It is the policy of the journal that all animal experiments should comply with the ARRIVE guidelines and should be carried out in accordance with the U.K. Animals (Scientific Procedures) Act, 1986 and associated guidelines, EU Directive 2010/63/EU for animal experiments, or the National Research Council's Guide for the Care and Use of Laboratory Animals. The authors have also informed the editors that the results of the IL-1β ELISA are not reliable due to issues with the reagents. Concern was also raised about the reliability of the Western blot results in Figure 5, which appear to contain suspected similarities between the P-P38 and Iκ Bα blots, as detailed here: https://pubpeer.com/publications/C87E1CABF28D49C30B80A05DF2C3DB#1. The journal requested the corresponding author comment on these concerns and provide the raw data. The journal did not receive a response to this request.

Betulin inhibited cigarette smoke-induced COPD in mice

The purpose of the present study was to evaluate the protective effect of betulin (BE) on CS (cigarette smoke)-induced COPD in mice and explore its underlying mechanisms. 60 male ICR mice were randomly assigned to five groups: control group, model group, dexamethasone (2mg/kg) group, BE (20mg/kg) group and BE (40mg/kg) group. The COPD mice were induced by cigarette smoke exposure for 8 weeks. The result of H&E staining demonstrated that BE inhibited CS-induced pathological injury in lung tissue. Besides, BE could restore the activities of superoxide dismutase (SOD) in serum and in lung, catalase (CAT) in serum and reduce the content of malondialdehyde (MDA) in serum and in lung. BE also inhibited the overproductions of pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β). Furthermore, the administration of BE significantly inhibited the protein expression of ROCK/NF-κB pathway in CS-induced mice. Our findings suggested that BE might effectively ameliorate the progression of COPD via ROCK/NF-κB pathway in mice.

GSK621 activates AMPK signaling to inhibit LPS-induced TNFα production

LPS stimulation in macrophages/monocytes induces TNFα production. We here tested the potential effect of GSK621, a novel AMP-activated protein kinase (AMPK) activator, against the process. In RAW264.7 macrophages, murine bone marrow-derived macrophages (BMDMs), and chronic obstructive pulmonary disease (COPD) patients' monocytes, GSK621 significantly inhibited LPS-induced TNFα protein secretion and mRNA synthesis. Inhibition of AMPK, through AMPKα shRNA knockdown or dominant negative mutation (T172A), almost abolished GSK621's suppression on TNFα in RAW264.7 cells. Reversely, forced-expression of a constitutively-active AMPKα (T172D) mimicked GSK621 actions and reduced LPS-induced TNFα production. Molecularly, GSK621 suppressed LPS-induced reactive oxygen species (ROS) production and nuclear factor kappa B (NFκB) activation. In vivo, GSK621 oral administration inhibited LPS-induced TNFα production and endotoxin shock in mice. In summary, GSK621 activates AMPK signaling to inhibit LPS-induced TNFα production in macrophages/monocytes.

Anti-inflammatory effect of Yu-Ping-Feng-San via TGF-β1 signaling suppression in rat model of COPD

OBJECTIVES

Yu-Ping-Feng-San (YPFS) is a classical traditional Chinese medicine that is widely used for treatment of the diseases in respiratory systems, including chronic obstructive pulmonary disease (COPD) recognized as chronic inflammatory disease. However, the molecular mechanism remains unclear. Here we detected the factors involved in transforming growth factor beta 1 (TGF-β1)/Smad2 signaling pathway and inflammatory cytokines, to clarify whether YPFS could attenuate inflammatory response dependent on TGF-β1/Smad2 signaling in COPD rats or cigarette smoke extract (CSE)-treated human bronchial epithelial (Beas-2B) cells.

MATERIALS AND METHODS

The COPD rat model was established by exposure to cigarette smoke and intratracheal instillation of lipopolysaccharide, YPFS was administered to the animals. The efficacy of YPFS was evaluated by comparing the severity of pulmonary pathological damage, pro-inflammation cytokines, collagen related genes and the activation of TGF-β1/Smad2 signaling pathway. Furthermore, CSE-treated cells were employed to confirm whether the effect of YPFS was dependent on the TGF-β1/Smad2 signaling via knockdown Smad2 (Si-RNA), or pretreatment with the inhibitor of TGF-β1.

RESULTS

Administration of YPFS effectively alleviated injury of lung, suppressed releasing of pro-inflammatory cytokines and collagen deposition in COPD animals (P<0.05), whereas exogenous TGF-β1 promoted releasing of IL-1β, IL-6, TNFα (P<0.05). Administration YPFS reduced inflammatory response significantly, also down-regulated TGF-β1/Smad2 signaling in vivo and in vitro. Unexpectedly, knockdown Smad2 or inhibition of TGF-β1 abolished anti-inflammatory effect of YPFS in CSE-treated cells.

CONCLUSION

YPFS accomplished anti-inflammatory effects mainly by suppressing phosphorylation of Smad2, TGF-β1/Smad2 signaling pathway was required for YPFS-mediated anti-inflammation in COPD rats or CSE-treated Beas-2B cells.

Considerations for the Conduct of Clinical Trials with Antiinflammatory Agents in Cystic Fibrosis. A Cystic Fibrosis Foundation Workshop Report

Inflammation leads to lung destruction and loss of pulmonary function in patients with cystic fibrosis (CF). Drugs that modulate the cystic fibrosis transmembrane conductance regulator (CFTR) have recently been approved. Although the impact of CFTR modulators on sweat chloride and lung function are exciting, they have not yet demonstrated an effect on inflammation. Therefore, CF antiinflammatory drug development must continue. Unfortunately, the lack of clarity with this process has left investigators and industry sponsors frustrated. The Cystic Fibrosis Foundation established a working group in early 2014 to address this issue. There are many inflammatory processes disrupted in CF, and, therefore, there are many potential targets amenable to antiinflammatory therapy. Regardless of a drug's specific mechanism of action, it must ultimately affect the neutrophil or its products to impact CF. The working group concluded that before bringing new antiinflammatory drugs to clinical trial, preclinical safety studies must be conducted in disease-relevant models to assuage safety concerns. Furthermore, although studies of antiinflammatory therapies must first establish safety in adults, subsequent studies must involve children, as they are most likely to reap the most benefit. The working group also recommended that pharmacokinetic-pharmacodynamic studies and early-phase safety studies be performed before proceeding to larger studies of longer duration. In addition, innovative study designs may improve the likelihood of adequately assessing treatment response and mitigating risk before conducting multiyear studies. Learning from past experiences and incorporating this knowledge into new drug development programs will be instrumental in bringing new antiinflammatory therapies to patients.

Autocrine Acetylcholine, Induced by IL-17A via NFκB and ERK1/2 Pathway Activation, Promotes MUC5AC and IL-8 Synthesis in Bronchial Epithelial Cells

IL-17A is overexpressed in the lung during acute neutrophilic inflammation. Acetylcholine (ACh) increases IL-8 and Muc5AC production in airway epithelial cells. We aimed to characterize the involvement of nonneuronal components of cholinergic system on IL-8 and Muc5AC production in bronchial epithelial cells stimulated with IL-17A. Bronchial epithelial cells were stimulated with recombinant human IL-17A (rhIL-17A) to evaluate the ChAT expression, the ACh binding and production, the IL-8 release, and the Muc5AC production. Furthermore, the effectiveness of PD098,059 (inhibitor of MAPKK activation), Bay11-7082 (inhibitor of IkBα phosphorylation), Hemicholinium-3 (HCh-3) (choline uptake blocker), and Tiotropium bromide (Spiriva®) (anticholinergic drug) was tested in our in vitro model. We showed that rhIL-17A increased the expression of ChAT, the levels of ACh binding and production, and the IL-8 and Muc5AC production in stimulated bronchial epithelial cells compared with untreated cells. The pretreatment of the cells with PD098,059 and Bay11-7082 decreased the ChAT expression and the ACh production/binding, while HCh-3 and Tiotropium decreased the IL-8 and Muc5AC synthesis in bronchial epithelial cells stimulated with rhIL-17A. IL-17A is involved in the IL-8 and Muc5AC production promoting, via NFκB and ERK1/2 pathway activation, the synthesis of ChAT, and the related activity of autocrine ACh in bronchial epithelial cells.

The potential role of phosphodiesterase inhibitors in the management of asthma

Asthma is a chronic inflammatory condition characterised by reversible airflow obstruction and airway hyperreactivity. The course of the illness may be punctuated by exacerbations resulting in deterioration in quality of life and, in some cases, days lost from school or work. That asthma is common and increasingly prevalent magnifies the importance of any potential economic costs, and promoting asthma control represents an important public health agenda. While lifestyle changes represent a valuable contribution in some patients, the majority of asthmatic patients require therapeutic intervention. The recognition of the role of inflammation in the pathogenesis of asthma has led to an emphasis on regular anti-inflammatory therapy, of which inhaled corticosteroid treatment remains the most superior. In selected patients, further improvements in asthma control may be gained by the addition of regular inhaled long-acting beta(2)-adrenoceptor agonists or oral leukotriene receptor antagonists to inhaled corticosteroid therapy. However, a significant minority of patients with asthma remain poorly controlled despite appropriate treatment, suggesting that additional corticosteroid nonresponsive inflammatory pathways may be operative. Furthermore, some patients with asthma display an accelerated decline in lung function, suggesting that active airway re-modeling is occurring. Such observations have focused attention on the potential to develop new therapies which complement existing treatments by targeting additional inflammatory pathways. The central role of phosphodiesterase (PDE), and in particular the PDE4 enzyme, in the regulation of key inflammatory cells believed to be important in asthma - including eosinophils, lymphocytes, neutrophils and airway smooth muscle - suggests that drugs designed to target this enzyme will have the potential to deliver both bronchodilation and modulate the asthmatic inflammatory response. In vivo studies on individual inflammatory cells suggest that the effects are likely to be favorable in asthma, and animal study models have provided proof of concept; however, first-generation PDE inhibitors have been poorly tolerated due to adverse effects. The development of second-generation agents such as cilomilast and roflumilast heralds a further opportunity to test the potential of these agents, although to date only a limited amount of data from human studies has been published, making it difficult to draw firm conclusions.

Phosphodiesterase 4 inhibitors for the treatment of chronic obstructive pulmonary disease: a review of current and developing drugs

INTRODUCTION

Phosphodiesterase (PDE) inhibitors modulate lung inflammation and cause bronchodilation by increasing intracellular cyclic adenosine 3', 5'-monophosphate in airway smooth muscle and inflammatory cells. Roflumilast is the only approved PDE-4 inhibitor (PDE4I) for use in chronic obstructive pulmonary disease (COPD). Its beneficial clinical effects occur preferentially in patients with chronic bronchitis and frequent COPD exacerbations. Use of roflumilast as adjunctive or alternate therapy to other COPD medications reduces exacerbations and modestly improves lung function.

AREAS COVERED

This article reviews the current role of PDE4I in COPD treatment emphasizing roflumilast's clinical efficacy and adverse effects. This article also reviews developing PDE4Is in early clinical trials and in preclinical studies.

EXPERT OPINION

After decades of research in drug development, PDE4Is are a welcomed addition to the COPD therapeutic armamentarium. In its current clinical role, the salubrious clinical effects of PDE4I in reducing exacerbations and stabilizing the frequent exacerbator phenotype have to be cautiously balanced with numerous adverse effects. Developing drugs may provide similar or better clinical benefits while minimizing adverse effects by changing the mode of drug delivery to inhaled formulations, combining dual PDE isoenzyme inhibitors (PDE1/4I and PDE3/4I) and by forming hybrid molecules with other bronchodilators (muscarinic receptor antagonist/PDE4I and β2-agonist/PDE4I).

AS-703026 Inhibits LPS-Induced TNFα Production through MEK/ERK Dependent and Independent Mechanisms

Chronic obstructive pulmonary disease (COPD) is characterized by intense lung infiltrations of immune cells (macrophages and monocytes). Lipopolysaccharide (LPS) activates macrophages/monocytes, leading to production of tumor necrosis factor α (TNFα) and other cytokines, which cause subsequent lung damages. In the current study, our results demonstrated that AS-703026, a novel MEK/ERK inhibitor, suppressed LPS-induced TNFα mRNA expression and protein secretion in RAW 264.7 murine macrophages, and in murine bone marrow-derived macrophages (BMDMs). Meanwhile, TNFα production in LPS-stimulated COPD patents’ peripheral blood mononuclear cells (PBMCs) was also repressed by AS-703026. At the molecular level, we showed that AS-703026 blocked LPS-induced MEK/ERK activation in above macrophages/monocytes. However, restoring ERK activation in AS-703026-treated RAW 264.7 cells by introducing a constitutive-actively (CA)-ERK1 only partially reinstated LPS-mediated TNFα production. Meanwhile, AS-703026 could still inhibit TNFα response in ERK1/2-depleted (by shRNA) RAW 264.7 cells. Significantly, we found that AS-703026 inhibited LPS-induced nuclear factor κB (NFκB) activation in above macrophages and COPD patients’ PBMCs. In vivo, oral administration of AS-703026 inhibited LPS-induced TNFα production and endotoxin shock in BALB/c mice. Together, we show that AS-703026 in vitro inhibits LPS-induced TNFα production in macrophages/monocytes, and in vivo protects mice from LPS-induced endotoxin shock. Thus, it could be further studied as a useful anti-inflammatory therapy for COPD patients.

Pathophysiology of tobacco smoke exposure: recent insights from comparative and redox proteomics

First-hand and second-hand tobacco smoke are causally linked to a huge number of deaths and are responsible for a broad spectrum of pathologies such as cancer, cardiovascular, respiratory, and eye diseases as well as adverse effects on female reproductive function. Cigarette smoke is a complex mixture of thousands of different chemical species, which exert their negative effects on macromolecules and biochemical pathways, both directly and indirectly. Many compounds can act as oxidants, pro-inflammatory agents, carcinogens, or a combination of these. The redox behavior of cigarette smoke has many implications for smoke related diseases. Reactive oxygen and nitrogen species (both radicals and non-radicals), reactive carbonyl compounds, and other species may induce oxidative damage in almost all the biological macromolecules, compromising their structure and/or function. Different quantitative and redox proteomic approaches have been applied in vitro and in vivo to evaluate, respectively, changes in protein expression and specific oxidative protein modifications induced by exposure to cigarette smoke and are overviewed in this review. Many gel-based and gel-free proteomic techniques have already been used successfully to obtain clues about smoke effects on different proteins in cell cultures, animal models, and humans. The further implementation with other sensitive screening techniques could be useful to integrate the comprehension of cigarette smoke effects on human health. In particular, the redox proteomic approach may also help identify biomarkers of exposure to tobacco smoke useful for preventing these effects or potentially predictive of the onset and/or progression of smoking-induced diseases as well as potential targets for therapeutic strategies.

Cytokine inhibition in the treatment of COPD

Cytokines play an important part in many pathobiological processes of chronic obstructive pulmonary disease (COPD), including the chronic inflammatory process, emphysema, and altered innate immune response. Proinflammatory cytokines of potential importance include tumor necrosis factor (TNF)-α, interferon-γ, interleukin (IL)-1β, IL-6, IL-17, IL-18, IL-32, and thymic stromal lymphopoietin (TSLP), and growth factors such as transforming growth factor-β. The current objectives of COPD treatment are to reduce symptoms, and to prevent and reduce the number of exacerbations. While current treatments achieve these goals to a certain extent, preventing the decline in lung function is not currently achievable. In addition, reversal of corticosteroid insensitivity and control of the fibrotic process while reducing the emphysematous process could also be controlled by specific cytokines. The abnormal pathobiological process of COPD may contribute to these fundamental characteristics of COPD, and therefore targeting cytokines involved may be a fruitful endeavor. Although there has been much work that has implicated various cytokines as potentially playing an important role in COPD, there have been very few studies that have examined the effect of specific cytokine blockade in COPD. The two largest studies that have been reported in the literature involve the use of blocking antibody to TNFα and CXCL8 (IL-8), and neither has provided benefit. Blocking the actions of CXCL8 through its CXCR2 receptor blockade was not successful either. Studies of antibodies against IL-17, IL-18, IL-1β, and TSLP are currently either being undertaken or planned. There is a need to carefully phenotype COPD and discover good biomarkers of drug efficacy for each specific target. Specific groups of COPD patients should be targeted with specific anticytokine therapy if there is evidence of high expression of that cytokine and there are features of the clinical expression of COPD that will respond.

Adjuvant system AS02V enhances humoral and cellular immune responses to pneumococcal protein PhtD vaccine in healthy young and older adults: randomised, controlled trials

BACKGROUND

The protection elicited by polysaccharide pneumococcal vaccines against community-acquired pneumonia in older adults remains debatable. Alternative vaccine targets include well-conserved pneumococcal protein antigens, such as pneumococcal histidine triad protein D (PhtD).

OBJECTIVE

To evaluate humoral and cellular immune responses and safety/reactogenicity following immunisation with PhtD vaccine with or without adjuvant (alum or AS02V) in older (≥65 years) and young (18-45 years) healthy adults.

METHODS

Two phase I/II, single-blind, parallel-group studies were conducted in 150 older and 147 young adults. Participants were randomised to receive 2 doses (months 0 and 2) of PhtD 30 μg, PhtD 10 μg plus alum, PhtD 30 μg plus alum, PhtD 10 μg plus AS02V or PhtD 30 μg plus AS02V, or the 23-valent polysaccharide pneumococcal vaccine (23PPV) at month 0 with placebo (saline solution) at month 2. Safety/reactogenicity was assessed. PhtD-specific antibody, T cell and memory B cell responses were evaluated.

RESULTS

Solicited adverse events were more common in young participants and with adjuvanted vaccines. No vaccine-related serious adverse events were reported. Although anti-PhtD geometric mean antibody concentrations (GMCs) were consistently lower in the older adult cohort than in young adults, GMCs in the older cohort following PhtD 30 μg plus AS02V were comparable to those induced by plain PhtD or PhtD 30 μg plus alum in the young cohort. Compared with alum adjuvant, AS02V adjuvant system was associated with an increased frequency of PhtD-specific CD4 cells in both cohorts and a significantly higher specific memory B cell response in the older cohort, similar to responses obtained in the young cohort.

CONCLUSION

The improved immune response to PhtD vaccine containing the AS02V adjuvant system in comparison to alum suggests that the reduced immune response to vaccines in older adults can be partially restored to the response level observed in young adults. ClinicalTrials.gov identifiers: NCT00307528/NCT01767402.

The phosphodiesterase 4 inhibitor rolipram protects against cigarette smoke extract-induced apoptosis in human lung fibroblasts

Cigarette smoke, a major causative agent of chronic obstructive pulmonary disease (COPD), induces lung cell death by incompletely understood mechanisms. The induction of apoptosis in lung structural cells by cigarette smoke may contribute to the pathogenesis of emphysema. Phosphodiesterase-4 (PDE4) inhibitors are anti-inflammatory agents used in COPD therapy that can prevent cigarette smoke-induced emphysema in mice. We investigated the effect of rolipram, a first generation PDE4 inhibitor, on the regulation of cigarette smoke-induced apoptosis. Human lung fibroblast (MRC-5) cells were exposed to cigarette smoke extract (CSE). Cell viability and apoptosis were determined by MTT assay and Annexin-V staining, respectively. Caspase activation was determined by Western immunoblot analysis. Rolipram protected against cell death and increased viability in MRC-5 fibroblasts after CSE exposure. Furthermore, rolipram protected against apoptosis, decreased caspase-3 and -8 cleavage in MRC-5 cells exposed to CSE. Pre-treatment with rolipram enhanced Akt phosphorylation and associated cytoprotection in CSE-treated cells, which could be reversed by the PI3K inhibitor LY294002 partly. In conclusion, rolipram protects against apoptosis of MRC-5 cells through inhibition of caspase-3 and caspase-8. Rolipram may represent an effective therapeutic agent to reduce cigarette smoke-induced apoptosis of lung fibroblasts.

Lack of Pharmacokinetic Interactions Between Cilomilast and Theophylline or Smoking in Healthy Volunteers

The pharmacokinetic profile of cilomilast (Ariflo), a selective phosphodiesterase 4 (PDE4) inhibitor, was investigated in three separate studies. Two of these studies explored the drug interaction potential of cilomilast with the nonselective PDE inhibitor, theophylline, and a third study compared the pharmacokinetic profile of cilomilast in smokers and nonsmokers. Repeated administration of cilomilast had no effect on the steady-state pharmacokinetics of theophylline in either a pilot dose-ranging or definitive therapeutic study. At therapeutic doses, the point estimate and 90% confidence interval for theophylline AUC(0-12) and C(max) were completely contained within the range (0.8, 1.25). Similarly, repeated administration of theophylline had little clinically relevant effect on the steady-state pharmacokinetics of cilomilast when compared to placebo, as only slight average increases in cilomilast AUC(0-12) and C(max) (6% and 3%, respectively) were observed. In addition, mean cilomilast exposure (AUC(0- infinity )) was found to be similar in both smokers and nonsmokers (8.47 +/- 2.20 microg*h/mL and 7.70 +/- 2.25 microg*h/mL, respectively). Throughout all three studies, cilomilast was well tolerated, and concomitant use of these selective and nonselective inhibitors, although unlikely in the clinic, is hypothetically feasible. Taken together, these studies clearly differentiate cilomilast from theophylline for drug-drug liability issues in a smoker and nonsmoker population, as well as highlight the potential to switch from one drug to another without undue clinical concern.

Anti-inflammatory Effect of Triterpenoic Acids of Eriobotrya japonica (Thunb.) Lindl. Leaf on Rat Model of Chronic Bronchitis

This study was designed to investigate the anti-inflammatory effect of Triterpenoic Acids from Eriobotrya japonica (Thunb.) Lindl. (TAL) on chronic bronchitis (CB) in rats. CB model was established by combination of Bacillus Calmette-Guerin (BCG, 5 mg/kg, injected through the caudal vein) and lipopolysaccharide (LPS, 1 g/L, injected through endotracheal intubation). Rats with CB model were treated with TAL (50, 150 and 450 mg/kg) for 3 weeks. The leukocytes in bronchoalveolar lavage fluid (BALF) were counted after Wright staining, the levels of cytokine tumor necrosis factor alpha (TNF-α), interleukin (IL)-8, and IL-10 in the supernatants of lung homogenate were assessed by enzyme-linked immunosorbent assay (ELISA), and the protein expression of nuclear factor kappaB (NF-κB) and intercellular adhesion molecule-1 (ICAM-1) on bronchial epithelium were tested by immunohistochemical staining. As compared to the normal and sham groups, the total number of leukocyte, the differential counts of neutrophils and alveolar macrophage (AM) in BALF, the levels of TNF-α and IL-8 in the supernatants of lung homogenate, and the expression of NF-κB and ICAM-1 on bronchial epithelium in CB rats were significantly increased, while the level of IL-10 was decreased. TAL (50, 150 and 450 mg/kg) attenuated these alterations in model CB rats, which indicates that TAL has anti-inflammatory effect in the rats with CB.

PDE4: a novel target in the treatment of chronic obstructive pulmonary disease

Phosphodiesterases (PDEs) are important modulators of inflammation and wound healing. In this capacity, specific targeting of PDEs for the treatment of many diseases, including chronic obstructive pulmonary disease (COPD), has been investigated. Currently, treatment of COPD is suboptimal. PDE4 modulates the inflammatory response of the lung, and inhibition of PDE4 may be a novel, COPD-specific approach toward more effective treatment strategies. This review describes the state of PDE4-inhibitor therapy for use in COPD treatment.

Reduced glucocorticoid receptor expression and function in airway neutrophils

Chronic Obstructive Pulmonary Disease (COPD) is a glucocorticoid resistant condition characterised by airway neutrophilia. Reduced glucocorticoid receptor (GR) expression in COPD airway neutrophils may be a mechanism that contributes to glucocorticoid resistance. Our objective was to investigate the expression and function of GR within COPD airway neutrophils. Dual-label immunofluorescence was used to analyse airway neutrophil expression of GR within peripheral lung tissue samples (11 COPD patients, 7 healthy non-smokers [NS]) and induced sputum (7 COPD patients, 7 NS). TNFα and CXCL8 release were measured in neutrophils isolated from induced sputum and peripheral blood (7 COPD patients) in the presence of dexamethasone. In lung tissue, GR was abundantly expressed in macrophages and lymphocytes, but very low expression was observed in neutrophils (means 6.8% and 4.3% in COPD patients and NS respectively). Similarly low expression was observed in sputum neutrophils (means 3.8% and 6.9% in COPD patients and NS respectively). In contrast, GR was expressed by 100% of blood neutrophils. Dexamethasone had less suppressive effect on TNFα and CXCL8 production in vitro by neutrophils from induced sputum compared to neutrophils from paired blood samples. Airway neutrophils have low expression of GR in both COPD patients and controls. The effects of glucocorticoids on cytokine production from airway neutrophils are reduced. Increased numbers of airway neutrophils lacking GR may contribute to glucocorticoid resistance in COPD patients.

Erythromycin prevents the pulmonary inflammation induced by exposure to cigarette smoke

The effect of erythromycin on the inflammation caused by exposure to cigarette smoke was investigated in this study. Mice were exposed either to cigarette smoke or to environmental air (control), and some mice exposed to cigarette smoke were treated with oral erythromycin (100 mg/kg/day for 8 days). Pulmonary inflammation was assessed by determining the cellular content of bronchoalveolar lavage (BAL) fluid. The messenger RNA (mRNA) levels of various mediators, including keratinocyte-derived chemokine (KC), macrophage inflammatory protein (MIP)-2, surfactant protein (SP)-D, granulocyte macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor (TNF)-α, interleukin (IL)-6 in lung tissue were determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays. The exposure to cigarette smoke increased significantly the numbers of neutrophils (P = 0.029), macrophages (P = 0.029), and lymphocytes (P = 0.029) recovered in BAL fluid. Moreover, mRNA levels of KC (P = 0.029), MIP-2 (P = 0.029), SP-D (P = 0.029), and GM-CSF (P = 0.057) in the lung tissue were higher in mice exposed to cigarette smoke than in mice exposed to environmental air. In the erythromycin-treated mice that were exposed also to cigarette smoke, both neutrophil and lymphocyte counts were significantly lower in the BAL fluid than those in the vehicle-treated mice (P = 0.029). Erythromycin-treated mice exposed to cigarette smoke showed a trend of lower mRNA levels of KC and TNF-α in the lung tissue than those in the vehicle-treated mice, although the statistical significance was not achieved (P = 0.057). Our data demonstrated that erythromycin prevented lung inflammation induced by cigarette smoke, in parallel to the reduced mRNA levels of KC and TNF-α.

Inhibition of granulocyte migration by tiotropium bromide

STUDY OBJECTIVES

Neutrophil influx into the airways is an important mechanism in the pathophysiology of the inflammatory process in the airways of patients with chronic obstructive pulmonary disease (COPD). Previously it was shown that anticholinergic drugs reduce the release of non-neuronal paracrine mediators, which modulate inflammation in the airways. On this basis, we investigated the ability of the long-acting anticholinergic tiotropium bromide to inhibit a) alveolar macrophage (AM)-mediated chemotaxis of neutrophils, and b) cellular release of reactive oxygen species (ROS).

METHOD

AM and neutrophils were collected from 71 COPD patients. Nanomolar concentrations of tiotropium bromide were tested in AM cultured up to 20 h with LPS (1 μg/ml). AM supernatant was tested for TNFα, IL8, IL6, LTB4, GM-CSF, MIPα/β and ROS. It was further used in a 96-well chemotaxis chamber to stimulate the migration of fluorescence labelled neutrophils. Control stimulants consisted of acetylcholine (ACh), carbachol, muscarine or oxotremorine and in part PMA (phorbol myristate acetate, 0.1 μg/ml). Potential contribution of M1-3-receptors was ascertained by a) analysis of mRNA transcription by RT-PCR, and b) co-incubation with selective M-receptor inhibitors.

RESULTS

Supernatant from AM stimulated with LPS induced neutrophilic migration which could be reduced by tiotropium in a dose dependent manner: 22.1 ± 10.2 (3 nM), 26.5 ± 18,4 (30 nM), and 37.8 ± 24.0 (300 nM, p < 0.001 compared to non-LPS activated AM). Concomitantly TNFα release of stimulated AM dropped by 19.2 ± 7.2% of control (p = 0.001). Tiotropium bromide did not affect cellular IL8, IL6, LTB4, GM-CSF and MIPα/β release in this setting. Tiotropium (30 nM) reduced ROS release of LPS stimulated AM by 36.1 ± 15.2% (p = 0.002) and in carbachol stimulated AM by 46.2 ± 30.2 (p < 0.001). M3R gene expression dominated over M2R and M1R. Chemotaxis inhibitory effect of tiotropium bromide was mainly driven by M3R inhibition.

CONCLUSION

Our data confirm that inhibiting muscarinic cholinergic receptors with tiotropium bromide reduces TNFα mediated chemotactic properties and ROS release of human AM, and thus may contribute to lessen cellular inflammation.

Macrolide antibiotics broadly and distinctively inhibit cytokine and chemokine production by COPD sputum cells in vitro

Macrolide antibiotics are known to exert anti-inflammatory actions in vivo, including certain effects in COPD patients. In order to investigate the immunomodulatory profile of activity of macrolide antibiotics, we have studied the effects of azithromycin, clarithromycin, erythromycin and roxithromycin on the in vitro production of a panel of inflammatory mediators from cells isolated from human, steroid-naïve, COPD sputum samples. Macrolide effects were compared to three other commonly used anti-inflammatory compounds, the corticosteroid dexamethasone, the PDE4 inhibitor, roflumilast and the p38 kinase inhibitor, SB203580. Three of the four tested macrolides, azithromycin, clarithromycin and roxithromycin, exhibited pronounced, concentration-related reduction of IL-1β, IL-6, IL-10, TNF-α, CCL3, CCL5, CCL20, CCL22, CXCL1, CXCL5, and G-CSF release. Further slight inhibitory effects on IL-1α, CXCL8, GM-CSF, and PAI-1 production were also observed. Erythromycin was very weakly active. Qualitatively and quantitatively, macrolides exerted distinctive and, compared to other tested classes of compounds, more pronounced immunomodulatory effects, particularly in terms of chemokine (CCL3, CCL5, CCL20, CCL22, and CXCL5), IL-1β, G-CSF and PAI-1 release. The described modulation of inflammatory mediators could potentially contribute to further definition of biomarkers of macrolide anti-inflammatory activity in COPD.

PDE4-inhibitors: a novel, targeted therapy for obstructive airways disease

Roflumilast is a selective once daily, oral phosphodiesterase-4 inhibitor that has recently been registered in all European Union countries as novel targeted therapy for COPD, while FDA approval for the USA market is expected in 2011. In several phase III trials in patients with moderate to (very) severe COPD and in patients with symptoms of chronic bronchitis and recurrent exacerbations, roflumilast showed sustained clinical efficacy by improving lung function and by reducing exacerbation rates. These beneficial effects have also been demonstrated when added to long-acting bronchodilators (both LABA and LAMA), underscoring the anti-inflammatory activity of roflumilast in COPD. Pooled data analysis showed overall mild to moderate, mostly self-limiting adverse events, mainly consisting of nausea, diarrhea and weight loss. In this review we discuss the results of the 4 registration studies showing promising effects of roflumilast in COPD and provide an overview of the topics that still need to be addressed.

The role of adenosine receptors in regulating production of tumour necrosis factor-alpha and chemokines by human lung macrophages

BACKGROUND AND PURPOSE

Adenosine is a major endogenous regulator of macrophage function, and activates four specific adenosine receptors (A(1), A(2A), A(2B) and A(3)). Here, we have assessed in human lung macrophages the modulation of the expression of adenosine receptor mRNA by lipopolysaccharide (LPS), and the relative contributions of the different adenosine receptors to LPS-induced production of tumour necrosis factor (TNF)-alpha and chemokines.

EXPERIMENTAL APPROACH

Lung macrophages isolated from resected lungs were stimulated with LPS and treated with adenosine receptor agonists or/and antagonists. Adenosine receptor expression was assessed with qRT-PCR. Cytokines were measured in lung macrophage supernatants with elisa.

KEY RESULTS

LPS increased (about 400-fold) mRNA for A(2A) adenosine receptors, decreased mRNA for A(1) and A(2B), but had no effect on A(3) adenosine receptor mRNA. The adenosine receptor agonist NECA inhibited TNF-alpha production concentration dependently, whereas the A(1) receptor agonist, CCPA, and the A(3) receptor agonist, AB-MECA, inhibited TNF-alpha production only at concentrations affecting A(2A) receptors. NECA also inhibited the production of CCL chemokines (CCL2, CCL3, CCL4, CCL5) and CXCL chemokines (CXCL9 and CXCL10), but not that of CXCL1, CXCL8 and CXCL5. Reversal of NECA-induced inhibition of TNF-alpha and chemokine production by the selective A(2A) adenosine receptor antagonist ZM 241385, but not the A(2B) receptor antagonist, MRS 1754, or the A(3) receptor antagonist, MRS 1220, indicated involvement of A(2A) receptors.

CONCLUSIONS AND IMPLICATIONS

LPS up-regulated A(2A) adenosine receptor gene transcription, and this receptor subtype mediated inhibition of the LPS-induced production of TNF-alpha and of a subset of chemokines in human lung macrophages.