Increased expression of nuclear factor-kappaB in bronchial biopsies from smokers and patients with COPD

Inflammation and immune response in COPD: where do we stand?

Increasing evidence indicates that chronic inflammatory and immune responses play key roles in the development and progression of COPD. Recent data provide evidence for a role in the NLRP3 inflammasome in the airway inflammation observed in COPD. Cigarette smoke activates innate immune cells by triggering pattern recognition receptors (PRRs) to release “danger signal”. These signals act as ligands to Toll-like receptors (TLRs), triggering the production of cytokines and inducing innate inflammation. In smokers who develop COPD there appears to be a specific pattern of inflammation in the airways and parenchyma as a result of both innate and adaptive immune responses, with the predominance of CD8+ and CD4+ cells, and in the more severe disease, with the presence of lymphoid follicles containing B lymphocytes and T cells. Furthermore, viral and bacterial infections interfere with the chronic inflammation seen in stable COPD and exacerbations via pathogen-associated molecular patterns (PAMPs). Finally, autoimmunity is another novel aspect that may play a critical role in the pathogenesis of COPD. This review is un update of the currently discussed roles of inflammatory and immune responses in the pathogenesis of COPD.

TRPM5-mediated calcium uptake regulates mucin secretion from human colon goblet cells

Mucin 5AC (MUC5AC) is secreted by goblet cells of the respiratory tract and, surprisingly, also expressed de novo in mucus secreting cancer lines. siRNA-mediated knockdown of 7343 human gene products in a human colonic cancer goblet cell line (HT29-18N2) revealed new proteins, including a Ca(2+)-activated channel TRPM5, for MUC5AC secretion. TRPM5 was required for PMA and ATP-induced secretion of MUC5AC from the post-Golgi secretory granules. Stable knockdown of TRPM5 reduced a TRPM5-like current and ATP-mediated Ca(2+) signal. ATP-induced MUC5AC secretion depended strongly on Ca(2+) influx, which was markedly reduced in TRPM5 knockdown cells. The difference in ATP-induced Ca(2+) entry between control and TRPM5 knockdown cells was abrogated in the absence of extracellular Ca(2+) and by inhibition of the Na(+)/Ca(2+) exchanger (NCX). Accordingly, MUC5AC secretion was reduced by inhibition of NCX. Thus TRPM5 activation by ATP couples TRPM5-mediated Na(+) entry to promote Ca(2+) uptake via an NCX to trigger MUC5AC secretion. DOI:http://dx.doi.org/10.7554/eLife.00658.001.

Exposing a deadly alliance: novel insights into the biological links between COPD and lung cancer

Chronic obstructive pulmonary disease (COPD) affects more than 200 million people worldwide and is expected to become the third leading cause of death in 2020. COPD is characterized by progressive airflow limitation, due to a combination of chronic inflammation and remodeling of the small airways (bronchiolitis) and loss of elastic recoil caused by destruction of the alveolar walls (emphysema). Lung cancer is the most important cause of cancer-related death in the world. (Cigarette) smoking is the principal culprit causing both COPD and lung cancer; in addition, exposure to environmental tobacco smoke, biomass fuel smoke, coal smoke and outdoor air pollution have also been associated with an increased incidence of both diseases. Importantly, smokers with COPD--defined as either not fully reversible airflow limitation or emphysema--have a two- to four-fold increased risk to develop lung cancer. In this review, we highlight several of the genetic, epigenetic and inflammatory mechanisms, which link COPD and carcinogenesis in the lungs. Elucidating the biological pathways and networks, which underlie the increased susceptibility of lung cancer in patients with COPD, has important implications for screening, prevention, diagnosis and treatment of these two devastating pulmonary diseases.

Identification of proteomic signatures associated with lung cancer and COPD

Lung cancer (LC) and chronic obstructive pulmonary disease (COPD) commonly coexist in smokers, and the presence of COPD increases the risk of developing LC. The aim of this study was to identify distinct proteomic profiles able to discriminate these two pathological entities. Protein content was assessed in the bronchoalveolar lavage (BAL) of 60 patients classified in four groups: COPD, COPD and LC, LC without COPD, and control with neither COPD nor LC. Proteins were separated into spots by bidimensional polyacrylamide gel electrophoresis (2D-PAGE) and examined by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/TOF). A total of 40 proteins were differentially expressed in the LC and/or COPD groups as compared with the control group. Distinct protein profiles were identified and validated for each pathological entity (LC and COPD). The main networks involved were related to inflammatory signalling, free radical scavenging and oxidative stress response, and glycolysis and gluconeogenesis pathways. The most relevant signalling link between LC and COPD was through the NF-κB pathway. In conclusion, the protein profiles identified contribute to elucidate the underlying pathogenic pathways of both diseases, and provide new tools of potential use as biomarkers for the early diagnosis of LC.

BIOLOGICAL SIGNIFICANCE

Sequence coverage. The protein sequence coverage (95%) was estimated for specific proteins by the percentage of matching amino acids from the identified peptides having confidence greater than or equal to 95% divided by the total number of amino acids in the sequence. Ingenuity Pathways Analysis. Mapping of our proteins onto biological pathways and disease networks demonstrated that 22 proteins were linked to inflammatory signalling (p-value: 1.35 10(-08)-1.42 10(-02)), 15 proteins were associated with free radical scavenging and oxidative stress response (p-value: 4.93 10(-11)-1.27 10(-02)), and 9 proteins were related with glycolysis and gluconeogenesis pathways (p-value: 7.39 10(-09)-1.58 10(-02)).

Role of transcription factors in the pathogenesis of asthma and COPD

Inflammation is a central feature of asthma and chronic obstructive pulmonary disease (COPD). Despite recent advances in the knowledge of the pathogenesis of asthma and COPD, much more research on the molecular mechanisms of asthma and COPD are needed to aid the logical development of new therapies for these common and important diseases, particularly in COPD where no effective treatments currently exist. In the future the role of the activation/repression of different transcription factors and the genetic regulation of their expression in asthma and COPD may be an increasingly important aspect of research, as this may be one of the critical mechanisms regulating the expression of different clinical phenotypes and their responsiveness to therapy, particularly to anti-inflammatory drugs.

Identification of oxidative stress related proteins as biomarkers for lung cancer and chronic obstructive pulmonary disease in bronchoalveolar lavage

Lung cancer (LC) and chronic obstructive pulmonary disease (COPD) commonly coexist in smokers, and the presence of COPD increases the risk of developing LC. Cigarette smoke causes oxidative stress and an inflammatory response in lung cells, which in turn may be involved in COPD and lung cancer development. The aim of this study was to identify differential proteomic profiles related to oxidative stress response that were potentially involved in these two pathological entities. Protein content was assessed in the bronchoalveolar lavage (BAL) of 60 patients classified in four groups: COPD, COPD and LC, LC, and control (neither COPD nor LC). Proteins were separated into spots by two dimensional polyacrylamide gel electrophoresis (2D-PAGE) and examined by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/TOF). A total of 16 oxidative stress regulatory proteins were differentially expressed in BAL samples from LC and/or COPD patients as compared with the control group. A distinct proteomic reactive oxygen species (ROS) protein signature emerged that characterized lung cancer and COPD. In conclusion, our findings highlight the role of the oxidative stress response proteins in the pathogenic pathways of both diseases, and provide new candidate biomarkers and predictive tools for LC and COPD diagnosis.

Cigarette smoking and inflammation revisited

Despite the significant health risks resulting from tobacco use, the prevalence of smokers worldwide remains high. Cigarette smoking is one of the major sources of toxic chemical exposure to humans and is the greatest cause of preventable illnesses and premature death. The adverse consequences of smoking in various pathologies are mediated by its effects on the immune-inflammatory system. In this review, we aim to explore the effects of cigarette smoking on the inflammatory response and molecular mechanisms with emphasis on the nuclear factor kappa B (NF-kB) pathway. The effects of smoking on various inflammatory pathologies will be discussed, focusing on oral diseases, airway inflammation, chronic obstructive pulmonary disease (COPD) and inflammatory bowel diseases (IBD).

Phenotyping the heterogeneity of chronic obstructive pulmonary disease

COPD (chronic obstructive pulmonary disease) is a heterogeneous disease associated with significant morbidity and mortality. Current diagnostic criteria based on the presence of fixed airflow obstruction and symptoms do not integrate the complex pathological changes occurring within lung, do not define different airway inflammatory patterns, nor do they define different physiological changes or differences in structure as can be defined by imaging. Over recent years, there has been interest in describing this heterogeneity and using this information to subgroup patients into COPD phenotypes. Most approaches to phenotyping have considered disease at a single scale and have not integrated information from different scales (e.g. organ-whole person, tissue-organ, cell-tissue and gene-cell) of disease to provide multi-dimensional phenotypes. Integration of disease biology with clinical expression is critical to improve understanding of this disease. When combined with biostatistical modelling, this information may lead to identification of new drug targets, new end points for clinical trials and targeted treatment for subgroups of COPD patients. It is hoped this will ultimately improve COPD outcomes and represent a move towards personalised medicine. In the present review, we will consider these aspects of multi-dimensional phenotyping in more detail.

Cigarette smoke induced airway inflammation is independent of NF-κB signalling

RATIONALE

COPD is an inflammatory lung disease largely associated with exposure to cigarette smoke (CS). The mechanism by which CS leads to the pathogenesis of COPD is currently unclear; it is known however that many of the inflammatory mediators present in the COPD lung can be produced via the actions of the transcription factor Nuclear Factor-kappaB (NF-κB) and its upstream signalling kinase, Inhibitor of κB kinase-2 (IKK-2). Therefore the NF-κB/IKK-2 signalling pathway may represent a therapeutic target to attenuate the inflammation associated with COPD.

AIM

To use a range of assays, genetically modified animals and pharmacological tools to determine the role of NF-κB in CS-induced airway inflammation.

METHODS

NF-κB pathway activation was measured in pre-clinical models of CS-induced airway inflammation and in human lung tissue from COPD patients. This data was complemented by employing mice missing a functional NF-κB pathway in specific cell types (epithelial and myeloid cells) and with systemic inhibitors of IKK-2.

RESULTS

We showed in an airway inflammation model known to be NF-κB-dependent that the NF-κB pathway activity assays and modulators were functional in the mouse lung. Then, using the same methods, we demonstrated that the NF-κB pathway appears not to play an important role in the inflammation observed after exposure to CS. Furthermore, assaying human lung tissue revealed that in the clinical samples there was also no increase in NF-κB pathway activation in the COPD lung, suggesting that our pre-clinical data is translational to human disease.

CONCLUSIONS

In this study we present compelling evidence that the IKK-2/NF-κB signalling pathway does not play a prominent role in the inflammatory response to CS exposure and that this pathway may not be important in COPD pathogenesis.

Oxidative stress and innate immunity status in chickens exposed to high dose of ascorbic acid

The effects of high dose ascorbic acid (10 000 mg·kg(-1) in the diet) and the transition metal on the presence of oxidative stress in the internal organs of growing chicks, as well as on the innate immune system status, were investigated. Supplementation with a high dose of ascorbic acid had pro-inflammatory effects on the intestinal mucosa, and lysozyme levels were decreased significantly in all organs studied. High-dose ascorbic acid caused an imbalance between prooxidative and antioxidative activities and was associated with the generation of semiquinone radicals. We observed that ascorbic acid increased iron and cadmium absorption. When a high dose of ascorbic acid was applied, elevated kidney and intestinal mucosa iron concentrations were observed. The amount of free malondialdehyde in the above organs has increased as well. These data have important implications for the mechanism of the oxidative stress development under the influence of high dose of ascorbic acid, indicating the importance of the side reactions of the mitochondrial electron transport chain with the formation of semiquinone radicals and the role of transition metals in this process.

Chronic obstructive pulmonary disease: an update of treatment related to frequently associated comorbidities

Chronic obstructive pulmonary disease (COPD) is associated with a pulmonary inflammatory response to inhaled substances, and individuals with COPD often have raised levels of several circulating inflammatory markers indicating the presence of systemic inflammation. Recently, there has been increasing interest in comorbidities associated with COPD such as skeletal muscle dysfunction, cardiovascular disease, osteoporosis, diabetes and lung cancer. These conditions are associated with a similar inflammation-based patho-physiology to COPD, and may represent a lung inflammatory 'overspill' to distant organs. Cardiovascular disease is a significant cause of mortality in COPD, and the concepts of an inflammatory link raise the possibility that treatment for one organ may show benefits to comorbidities in other organs. When considering treatment of COPD and its comorbidities, one approach is to target the pulmonary inflammation and hence reduce any 'overspill' effect of inflammatory mediators systemically as suggested by response to inhaled corticosteroids. Alternatively, treatment targeted towards comorbid organs may alter features of pulmonary disease as statins, angiotensin-converting enzyme (ACE) inhibitors and peroxisome proliferator-activated receptor (PPAR) agonists may have beneficial effects on COPD by reducing exacerbations and mortality. Newer anti-inflammatory treatments, such as phosphodiesterase 4 (PDE4), nuclear factor(NF)-kB, and p38 mitogen-activated protein kinase (MAPK) inhibitors, are given systemically and may confer benefits to both COPD and its comorbidities. With common inflammatory pathways it might be expected that successful anti-inflammatory therapy in one organ may also influence others. In this review we explore the concepts of systemic inflammation in COPD and current evidence for treatment of its related comorbidities.

The role of endogenous H2S formation in reversible remodeling of lung tissue during hibernation in the Syrian hamster

During hibernation, small mammals alternate between periods of metabolic suppression and low body temperature ('torpor') and periods of full metabolic recovery with euthermic temperatures ('arousal'). Previously, we demonstrated marked structural remodeling of the lung during torpor, which is rapidly reversed during arousal. We also found that cooling of hamster cells increased endogenous production of H(2)S through the enzyme cystathionine-β-synthase (CBS). H(2)S suppresses the immune response and increases deposition of collagen. Therefore, we examined inflammatory markers and matrix metalloproteinase (MMP) activity in relation to CBS expression and H(2)S levels in lungs of euthermic and hibernating Syrian hamsters. Lung remodeling during torpor was confirmed by a strong increase in both collagenous and non-collagenous hydroxyproline content. The number of leukocytes in lung was unchanged in any phase of hibernation, while adhesion molecules VCAM-1 and ICAM-1, and the inflammatory marker NF-κB (P65) were modestly upregulated in torpor. Gelatinase activity was decreased in lungs from torpid animals, indicating inhibition of the Zn(2+)-dependent MMP-2 and MMP-9. Moreover, expression of CBS and tissue levels of H(2)S were increased in torpor. All changes normalized during arousal. Inhibition of gelatinase activity in torpor is likely caused by quenching of Zn(2+) by the sulphide ion of H(2)S. In accord, inhibition of CBS normalized gelatinase activity in torpid animals. Conversely, NaHS decreased the gelatinase activity of euthermic animals, which was attenuated by excess Zn(2+). Similar results were obtained on the activity of the Zn(2+)-dependent angiotensin converting enzyme. Our data indicate that increased production of H(2)S through CBS in hamster lungs during torpor contributes to remodeling by inhibition of gelatinase activity and possibly by suppression of the inflammatory response. Although administration of H(2)S is known to induce metabolic suppression in non-hibernating mammals ('suspended animation'), this is the first report implying endogenous H(2)S production in natural hibernation.

Defining critical roles for NF-κB p65 and type I interferon in innate immunity to rhinovirus

The importance of NF-κB activation and deficient anti-viral interferon induction in the pathogenesis of rhinovirus-induced asthma exacerbations is poorly understood. We provide the first in vivo evidence in man and mouse that rhinovirus infection enhanced bronchial epithelial cell NF-κB p65 nuclear expression, NF-κB p65 DNA binding in lung tissue and NF-κB-regulated airway inflammation. In vitro inhibition of NF-κB reduced rhinovirus-induced pro-inflammatory cytokines but did not affect type I/III interferon induction. Rhinovirus-infected p65-deficient mice exhibited reduced neutrophilic inflammation, yet interferon induction, antiviral responses and virus loads were unaffected, indicating that NF-κB p65 is required for pro-inflammatory responses, but redundant in interferon induction by rhinoviruses in vivo. Conversely, IFNAR1^−/− mice exhibited enhanced neutrophilic inflammation with impaired antiviral immunity and increased rhinovirus replication, demonstrating that interferon signalling was critical to antiviral immunity. We thus provide new mechanistic insights into rhinovirus infection and demonstrate the therapeutic potential of targeting NF-κB p65 (to suppress inflammation but preserve anti-viral immunity) and type I IFN signalling (to enhance deficient anti-viral immunity) to treat rhinovirus-induced exacerbations of airway diseases.

SIRT1 as a therapeutic target in inflammaging of the pulmonary disease

OBJECTIVE

Chronic inflammation and cellular senescence are intertwined in the pathogenesis of premature aging, which is considered as an important contributing factor in driving chronic obstructive pulmonary disease (COPD). Sirtuin1 (SIRT1), a nicotinamide adenine dinucleotide (NAD(+))-dependent protein/histone deacetylase, regulates inflammation, senescence/aging, stress resistance, and deoxyribonucleic acid (DNA) damage repair via deacetylating intracellular signaling molecules and chromatin histones. The present review describes the mechanism and regulation of SIRT1 by environmental agents/oxidants/reactive aldehydes and pro-inflammatory stimuli in lung inflammation and aging. The role of dietary polyphenols in regulation of SIRT1 in inflammaging is also discussed.

METHODS

Analysis of current research findings on the mechanism of inflammation and senescence/aging (i.e., inflammaging) and their regulation by SIRT1 in premature aging of the lung.

RESULTS

COPD is a disease of the lung inflammaging, which is associated with the DNA damage response, transcription activation and chromatin modifications. SIRT1 regulates inflammaging via regulating forkhead box class O 3, p53, nuclear factor kappa B, histones and various proteins involved in DNA damage and repair. Polyphenols and its analogs have been shown to activate SIRT1 although they have anti-inflammatory and antioxidant properties.

CONCLUSIONS

Targeting lung inflammation and cellular senescence as well as premature lung aging using pharmacological SIRT1 activators or polyphenols would be a promising therapeutic intervention for COPD/emphysema.

SIRT1 protects against emphysema via FOXO3-mediated reduction of premature senescence in mice

Chronic obstructive pulmonary disease/emphysema (COPD/emphysema) is characterized by chronic inflammation and premature lung aging. Anti-aging sirtuin 1 (SIRT1), a NAD+-dependent protein/histone deacetylase, is reduced in lungs of patients with COPD. However, the molecular signals underlying the premature aging in lungs, and whether SIRT1 protects against cellular senescence and various pathophysiological alterations in emphysema, remain unknown. Here, we showed increased cellular senescence in lungs of COPD patients. SIRT1 activation by both genetic overexpression and a selective pharmacological activator, SRT1720, attenuated stress-induced premature cellular senescence and protected against emphysema induced by cigarette smoke and elastase in mice. Ablation of Sirt1 in airway epithelium, but not in myeloid cells, aggravated airspace enlargement, impaired lung function, and reduced exercise tolerance. These effects were due to the ability of SIRT1 to deacetylate the FOXO3 transcription factor, since Foxo3 deficiency diminished the protective effect of SRT1720 on cellular senescence and emphysematous changes. Inhibition of lung inflammation by an NF-κB/IKK2 inhibitor did not have any beneficial effect on emphysema. Thus, SIRT1 protects against emphysema through FOXO3-mediated reduction of cellular senescence, independently of inflammation. Activation of SIRT1 may be an attractive therapeutic strategy in COPD/emphysema.

Leukocytes are recruited through the bronchial circulation to the lung in a spontaneously hypertensive rat model of COPD

Chronic obstructive pulmonary disease (COPD) kills approximately 2.8 million people each year, and more than 80% of COPD cases can be attributed to smoking. Leukocytes recruited to the lung contribute to COPD pathology by releasing reactive oxygen metabolites and proteolytic enzymes. In this work, we investigated where leukocytes enter the lung in the early stages of COPD in order to better understand their effect as a contributor to the development of COPD. We simultaneously evaluated the parenchyma and airways for neutrophil accumulation, as well as increases in the adhesion molecules and chemokines that cause leukocyte recruitment in the early stages of tobacco smoke induced lung disease. We found neutrophil accumulation and increased expression of adhesion molecules and chemokines in the bronchial blood vessels that correlated with the accumulation of leukocytes recovered from the lung. The expression of adhesion molecules and chemokines in other vascular beds did not correlate with leukocytes recovered in bronchoalveolar lavage fluid (BALF). These data strongly suggest leukocytes are recruited in large measure through the bronchial circulation in response to tobacco smoke. Our findings have important implications for understanding the etiology of COPD and suggest that pharmaceuticals designed to reduce leukocyte recruitment through the bronchial circulation may be a potential therapy to treat COPD.

Opposing effects of bortezomib-induced nuclear factor-κB inhibition on chemical lung carcinogenesis

Since recent evidence indicates a requirement for epithelial nuclear factor (NF)-κB signaling in lung tumorigenesis, we investigated the impact of the NF-κB inhibitor bortezomib on lung tumor promotion and growth. We used an experimental model in which wild-type mice or mice expressing an NF-κB reporter received intraperitoneal urethane (1 g/kg) followed by twice weekly bortezomib (1 mg/kg) during distinct periods of tumor initiation/progression. Mice were serially assessed for lung NF-κB activation, inflammation and carcinogenesis. Short-term proteasome inhibition with bortezomib did not impact tumor formation but retarded the growth of established lung tumors in mice via effects on cell proliferation. In contrast, long-term treatment with bortezomib resulted in significantly increased lung tumor number and size. This tumor-promoting effect of prolonged bortezomib treatment was associated with perpetuation of urethane-induced inflammation and chronic upregulation of interleukin-1β and proinflammatory C-X-C motif chemokine ligands (CXCL) 1 and 2 in the lungs. In addition to airway epithelium, bortezomib inhibited NF-κB in pulmonary macrophages in vivo, presenting a possible mechanism of tumor amplification. In this regard, RAW264.7 macrophages exposed to bortezomib showed increased expression of interleukin-1β, CXCL1 and CXCL2. In conclusion, although short-term bortezomib may exert some beneficial effects, prolonged NF-κB inhibition accelerates chemical lung carcinogenesis by perpetuating carcinogen-induced inflammation. Inhibition of NF-κB in pulmonary macrophages appears to play an important role in this adverse process.

Enhancement of lung tumorigenesis in a Gprc5a Knockout mouse by chronic extrinsic airway inflammation

Background

Although cigarette smoking is the principal cause of lung carcinogenesis, chronic obstructive pulmonary disease (COPD), an inflammatory disease of the lung, has been identified as an independent risk factor for lung cancer. Bacterial colonization, particularly with non-typeable Haemophilus influenzae (NTHi), has been implicated as a cause of airway inflammation in COPD besides cigarette smoke. Accordingly, we hypothesized that lung cancer promotion may occur in a chronic inflammatory environment in the absence of concurrent carcinogen exposure.

Results

Herein, we investigated the effects of bacterial-induced COPD-like inflammation and tobacco carcinogen-enhanced tumorigenesis/inflammation in the retinoic acid inducible G protein coupled receptor knock out mouse model (Gprc5a-/- mouse) characterized by late-onset, low multiplicity tumor formation. Three-month-old Gprc5a-/- mice received 4 intraperitoneal injections of the tobacco-specific carcinogen, NNK, followed by weekly exposure to aerosolized NTHi lysate for 6 months. The numbers of inflammatory cells in the lungs and levels of several inflammatory mediators were increased in Gprc5a-/- mice treated with NTHi alone, and even more so in mice pretreated with NNK followed by NTHi. The incidence of spontaneous lung lesions in the Gprc5a-/- mice was low, but NTHi exposure led to enhanced development of hyperplastic lesions. Gprc5a-/- mice exposed to NNK alone developed multiple lung tumors, while NTHi exposure increased the number of hyperplastic foci 6-fold and the tumor multiplicity 2-fold. This was associated with increased microvessel density and HIF-1α expression.

Conclusion

We conclude that chronic extrinsic lung inflammation induced by bacteria alone or in combination with NNK enhances lung tumorigenesis in Gprc5a-/- mice.

Convergent sets of data from in vivo and in vitro methods point to an active role of Hsp60 in chronic obstructive pulmonary disease pathogenesis

Background

It is increasingly clear that some heat shock proteins (Hsps) play a role in inflammation. Here, we report results showing participation of Hsp60 in the pathogenesis of chronic obstructive pulmonary diseases (COPD), as indicated by data from both in vivo and in vitro analyses.

Methods and Results

Bronchial biopsies from patients with stable COPD, smoker controls with normal lung function, and non-smoker controls were studied. We quantified by immunohistochemistry levels of Hsp10, Hsp27, Hsp40, Hsp60, Hsp70, Hsp90, and HSF-1, along with levels of inflammatory markers. Hsp10, Hsp40, and Hsp60 were increased during progression of disease. We found also a positive correlation between the number of neutrophils and Hsp60 levels. Double-immunostaining showed that Hsp60-positive neutrophils were significantly increased in COPD patients. We then investigated in vitro the effect on Hsp60 expression in bronchial epithelial cells (16HBE) caused by oxidative stress, a hallmark of COPD mucosa, which we induced with H₂O₂. This stressor determined increased levels of Hsp60 through a gene up-regulation mechanism involving NFkB-p65. Release of Hsp60 in the extracellular medium by the bronchial epithelial cells was also increased after H₂O₂ treatment in the absence of cell death.

Conclusions

This is the first report clearly pointing to participation of Hsps, particularly Hsp60, in COPD pathogenesis. Hsp60 induction by NFkB-p65 and its release by epithelial cells after oxidative stress can have a role in maintaining inflammation, e.g., by stimulating neutrophils activity. The data open new scenarios that might help in designing efficacious anti-inflammatory therapies centered on Hsp60 and applicable to COPD.

Reduced apoptosis of CD8+ T-lymphocytes in the airways of smokers with mild/moderate COPD

Chronic obstructive pulmonary disease (COPD) is characterised by chronic inflammation in airways and lung parenchyma. CD8+ T-lymphocytes, crucial effector and regulatory cells in inflammation, are increased in the central and peripheral airways in COPD. The aim of this study was to assess the role of apoptosis in the accumulation of CD8+ T-lymphocytes within the airway wall in COPD. We examined the submucosa of transverse sections of central and peripheral airways from post-operative tissues from non-smokers (n = 16), smokers with normal lung function (n = 16), smokers with mild/moderate COPD (n = 16), and smokers with severe/very severe COPD (n = 9). TUNEL and immunohistochemistry techniques were used to identify apoptosis and cell phenotype, respectively. The percentage of apoptotic CD8+ T-lymphocytes was significantly lower (p < 0.0001) in smokers with mild/moderate COPD than in non-smokers, smokers with normal lung function, and smokers with severe/very severe COPD, and was positively related to values of FEV(1) and FEV(1)/FVC ratio, both in central and in peripheral airways. These data suggest that reduced apoptosis of CD8+ T-lymphocytes may be an important mechanism that contributes to the accumulation of these cells in the airway submucosa in smokers with mild/moderate COPD.

IκB kinase-driven nuclear factor-κB activation in patients with asthma and chronic obstructive pulmonary disease

BACKGROUND

Nuclear factor-κB (NF-κB) is a transcriptional factor of different inflammatory patterns involved in asthma and chronic obstructive pulmonary disease (COPD) that is tightly controlled by IκB kinase (IKK) complex.

OBJECTIVE

We investigated the dysregulation of IKK-driven NF-κB activation in patients with asthma and COPD.

METHODS

We assessed IKKα and IKKβ expression and activation, their regulation by glucocorticosteroids, and their involvement in IL-8 synthesis in PBMCs isolated from asthmatic patients, healthy smokers (HSs), patients with COPD, and control subjects. PBMCs from control subjects were stimulated with TNF-α and cigarette smoke extract in the presence or absence of fluticasone propionate (FP), L-glutathione reduced, or both, and IKK activation and IL-8 release were evaluated.

RESULTS

IKKα activity was higher in patients with COPD and HSs than in asthmatic patients and control subjects. IKKβ activity was higher in asthmatic patients, HSs, and patients with COPD than in control subjects. In vitro FP treatment induced inhibition of both IKKα and IKKβ activity in PBMCs from asthmatic patients, patients with COPD, and HSs, although IKKβ activity was more sensitive to FP than that of IKKα. FP reduced the IL-8 released from PBMCs of asthmatic patients, patients with COPD, and HSs, although IL-8 inhibition was higher in asthmatic patients than in patients with COPD and HSs. FP reduced IKKα and IKKβ activities in TNF-α and cigarette smoke extract-treated PBMCs, with higher levels of inhibition for IKKβ than IKKα activity. L-glutathione reduced improved the downregulatory effects of FP on IKKα and IL-8 levels.

CONCLUSION

Based on differential activation of IKKα and IKKβ, our findings suggest a different profile in the upstream regulation of the IKK-driven NF-κB system in asthmatic patients and patients with COPD. These differences in the regulation of the inflammatory process may explain, at least in part, the different pharmacologic responses in these patients.

Correction of glycaemia and GLUT1 level by mildronate in rat streptozotocin diabetes mellitus model

Anti-ischaemic drug mildronate suppresses fatty acid metabolism and increases glucose utilization in myocardium. It was proposed that it could produce a favourable effect on metabolic parameters and glucose transport in diabetic animals. Rats with streptozotocin diabetes mellitus were treated with mildronate (100 mg/kg daily, per os, 6 weeks). Therapeutic effect of mildronate was monitored by measuring animal weight, concentrations of blood glucose, insulin, blood triglycerides, free fatty acids, blood ketone bodies and cholesterol, glycated haemoglobin per cent (HbA1c%) and glucose tolerance. GLUT1 mRNA and protein expression in kidneys, heart, liver and muscles were studied by means of real time RT-PCR and immunohistochemistry correspondingly. In the streptozotocin + mildronate group, mildronate treatment caused a significant decrease in mean blood glucose, cholesterol, free fatty acid and HbA1c concentrations and improved glucose tolerance. Induction of streptozotocin diabetes mellitus provoked increase of both GLUT1 gene and protein expression in kidneys, heart and muscle, mildronate treatment produced normalization of the GLUT1 expression levels. In the liver a similar effect was observed for GLUT1 protein expression, while GLUT1 gene expression was increased by mildronate. Mildronate produces therapeutic effect in streptozotocin diabetes model. Mildronate normalizes the GLUT1 expression up-regulated by streptozotocin diabetes mellitus in kidneys, heart, muscle and liver. Copyright © 2011 John Wiley & Sons, Ltd.

Dendritic cells and airway epithelial cells at the interface between innate and adaptive immune responses

Because they can recognize and sample inhaled allergens, dendritic cells (DC) have been shown to be responsible for the initiation and maintenance of adaptive Th2 responses in asthma. It is increasingly clear that DC functions are strongly influenced by a crosstalk with neighboring cells like epithelial cells. Whereas the epithelium was initially considered only as a barrier, it is now seen as a central player in controlling the function of lung DCs through release of innate cytokines-promoting Th2 responses. Clinically relevant allergens, as well as known environmental and genetic risk factors for allergy and asthma, often interfere directly or indirectly with the innate immune functions of airway epithelial cells and DC. A better understanding of these interactions might lead to a better prevention and ultimately to new treatments for asthma.

Innate immune responses are increased in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterised by irreversible airflow obstruction, neutrophilic airway inflammation and chronic bacterial colonisation, however the role of the innate immune response in the pathogenesis of COPD remains unclear.

METHODS

Induced sputum was obtained from adults with COPD (n=22), and healthy controls (n=29) and was processed for differential cell counts. The sputum supernatant was assayed for innate immune mediators using ELISA, whilst sputum gene expression was measured using real-time PCR. Peripheral blood neutrophils were isolated and their response to lipopolysaccaride (LPS) stimulation was assessed in a subgroup of participants with COPD (n=13) and healthy controls (n=21).

RESULTS

Participants with COPD had significantly higher protein levels of interleukin (IL)-8, and neutrophil elastase (NE) and detection of oncostatin M (OSM) compared to healthy controls. Gene expression for toll-like receptor (TLR) 2, IL-8 and OSM were also significantly higher in COPD participants. The level of IL-1β, surfactant protein (SP)-A, matrix metalloproteinase (MMP)-9 and TLR4 mRNA was not significantly different between groups. The level of innate immune response markers were highly associated with the presence of sputum neutrophils, each other and the degree of airflow limitation (FEV1/FVC). Peripheral blood neutrophils from participants with COPD had an increased response to stimulation by LPS; with a greater fold increase in the production of IL-8 and MMP-9 protein, and gene expression of IL-8, TLR2 and TLR4.

CONCLUSIONS

The innate immune response is increased in the airways and circulating neutrophils in COPD, and may be an important mechanism involved in disease pathogenesis.

Molecular mechanisms of inflammation during exacerbations of chronic obstructive pulmonary disease

INTRODUCTION

Exacerbations of chronic obstructive pulmonary disease (COPD) are characterised by an inflammatory and systemic response that persists for some time after their clinical resolution. The mechanisms of this inflammatory process are not well known.

OBJECTIVES

To explore the inflammatory changes and possible mechanisms during COPD exacerbation.

METHODS

We determined the inflammatory cell concentrations in blood and sputum, nitric oxide in exhaled air (FeNO), C-reactive protein (CRP) in plasma, cytokines (IL-6, 8, 1β, 10, 12, TNF-α) and SLPI (leukocyte protease inhibitor) and total antioxidant status (TAS) in blood and sputum, the activity of nuclear kappa B factor (NF-κ B) and of the histone deacetylase enzyme (HDAC) in 17 patients during COPD exacerbation and in stable phase, as well as in 17 smoker and 11 non-smoker controls.

RESULTS

COPD exacerbations are characterised by high levels of FeNO (p<0.05), plasma CRP (p<0.001) and IL-8, IL-1B, IL-10 in sputum (p<0.05) greater activation of NF-κ appaB in sputum macrophages compared with stable COPD and controls. During the stable phase, there continue to be high levels of oxidative stress, SLPI, IL-8, IL-6 and TNF-alfa, with no observed changes in either HDAC activity or in the amount of neutrophils in sputum, despite presenting a significant improvement (p<0.05) in lung function.

CONCLUSIONS

Changes were observed in different pulmonary and systemic inflammatory markers during COPD exacerbation, which did not completely resolve during stable phase. However, current treatment does not allow for HDAC activity to be modified, which limits its anti-inflammatory effects.

Chronic obstructive pulmonary disease and lung cancer: new molecular insights

Both chronic obstructive pulmonary disease (COPD) and lung cancer are major causes of death worldwide. In most cases this reflects cigarette smoke exposure which is able to induce an inflammatory response in the airways of smokers. Indeed, COPD is characterized by lower airway inflammation, and importantly, the presence of COPD is by far the greatest risk factor for lung cancer amongst smokers. Cigarette smoke induces the release of many inflammatory mediators and growth factors including TGF-β, EGFR, IL-1, IL-8 and G-CSF through oxidative stress pathways and this inflammation may persist for decades after smoking cessation. Mucus production is also increased by these inflammatory mediators, further linking airway inflammation to an important mechanism of lung cancer. A greater understanding of the molecular and cellular pathobiology that distinguishes smokers with lung cancer from smokers with and without COPD is needed to unravel the complex molecular interactions between COPD and lung cancer. By understanding the common signalling pathways involved in COPD and lung cancer the hope is that treatments will be developed that not only treat the underlying disease process in COPD, but also reduce the currently high risk of developing lung cancer in these patients.

Impact of smoking on inflammation: overview of molecular mechanisms

BACKGROUND

Inflammation is a critical component of normal tissue repair, as well as being fundamental to the body's defense against infection. Environmental factors, such as smoking, have been reported to modify the host response and hence modify inflammation progression, severity and outcome. Therefore, a comprehensive understanding of the molecular mechanisms by which smoking affects inflammation is vital for preventive and therapeutic strategies on a clinical level.

AIM

The purpose of the present article is to review the potential biological mechanisms by which smoking affects inflammation, emphasizing recent developments.

RESULTS

Smoking is reported to effect a number of biological mediators of inflammation through its effect on immune-inflammatory cells, leading to an immunosuppressant state. Recent evidence strongly suggests that the molecular mechanisms behind the modulation of inflammation by smoking mainly involve the nuclear factor-kappa B (NF-kB) family, through the activation of both an inhibitor of IkB kinase (IKK)-dependent and -independent pathway. In addition to NF-kB activation, a number of transcriptional factors including GATA, PAX5 and Smad 3/4, have also been implicated.

CONCLUSION

Multiple mechanisms may be responsible for the association of smoking and inflammation, and the identification of potential therapeutic targets should guide future research.

Current concepts on oxidative/carbonyl stress, inflammation and epigenetics in pathogenesis of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a global health problem. The current therapies for COPD are poorly effective and the mainstays of pharmacotherapy are bronchodilators. A better understanding of the pathobiology of COPD is critical for the development of novel therapies. In the present review, we have discussed the roles of oxidative/aldehyde stress, inflammation/immunity, and chromatin remodeling in the pathogenesis of COPD. An imbalance of oxidants/antioxidants caused by cigarette smoke and other pollutants/biomass fuels plays an important role in the pathogenesis of COPD by regulating redox-sensitive transcription factors (e.g., NF-κB), autophagy and unfolded protein response leading to chronic lung inflammatory response. Cigarette smoke also activates canonical/alternative NF-κB pathways and their upstream kinases leading to sustained inflammatory response in lungs. Recently, epigenetic regulation has been shown to be critical for the development of COPD because the expression/activity of enzymes that regulate these epigenetic modifications have been reported to be abnormal in airways of COPD patients. Hence, the significant advances made in understanding the pathophysiology of COPD as described herein will identify novel therapeutic targets for intervention in COPD.

Common pathogenic mechanisms and pathways in the development of COPD and lung cancer

INTRODUCTION

Lung cancer and COPD commonly coexist in smokers, and the presence of COPD increases the risk of developing lung cancer. In addition to smoking cessation and preventing smoking initiation, understanding the shared mechanisms of these smoking-related lung diseases is critical, in order to develop new methods of prevention, diagnosis and treatment of lung cancer and COPD.

AREAS COVERED

This review discusses the common mechanisms for susceptibility to lung cancer and COPD, which in addition to cigarette smoke, may involve inflammation, epithelial-mesenchymal transition, abnormal repair, oxidative stress, and cell proliferation. Furthermore, we discuss the underlying genomic and epigenomic changes (single nucleotide polymorphisms (SNPs), copy number variation, promoter hypermethylation and microRNAs) that are likely to alter biological pathways, leading to susceptibility to lung cancer and COPD (e.g., altered nicotine receptor biology).

EXPERT OPINION

Strategies to study genomics, epigenomics and gene-environment interaction will yield greater insight into the shared pathogenesis of lung cancer and COPD, leading to new diagnostic and therapeutic modalities.

Interleukin 6, but not T helper 2 cytokines, promotes lung carcinogenesis

Several epidemiologic studies have found that smokers with chronic obstructive pulmonary disease (COPD), an inflammatory disease of the lung, have an increased risk of lung cancer compared with smokers without COPD. We have shown a causal role for COPD-like airway inflammation in lung cancer promotion in the CCSP(Cre)/LSL-K-ras(G12D) mouse model (CC-LR). In contrast, existing epidemiologic data do not suggest any definite association between allergic airway inflammation and lung cancer. To test this, CC-LR mice were sensitized to ovalbumin (OVA) and then challenged with an OVA aerosol weekly for 8 weeks. This resulted in eosinophilic lung inflammation associated with increased levels of T helper 2 cytokines and mucous metaplasia of airway epithelium, similar to what is seen in asthmatic patients. However, this type of inflammation did not result in a significant difference in lung surface tumor number (49 ± 9 in OVA vs. 52 ± 5 in control) in contrast to a 3.2-fold increase with COPD-like inflammation. Gene expression analysis of nontypeable Haemophilus influenzae (NTHi)-treated lungs showed upregulation of a different profile of inflammatory genes, including interleukin 6 (IL-6), compared with OVA-treated lungs. Therefore, to determine the causal role of cytokines that mediate COPD-like inflammation in lung carcinogenesis, we genetically ablated IL-6 in CC-LR mice. This not only inhibited intrinsic lung cancer development (1.7-fold) but also inhibited the promoting effect of extrinsic COPD-like airway inflammation (2.6-fold). We conclude that there is a clear specificity for the nature of inflammation in lung cancer promotion, and IL-6 has an essential role in lung cancer promotion.

Asthma, chronic obstructive pulmonary disease, and type 2 diabetes in the Women's Health Study

BACKGROUND

Chronic airway inflammation in asthma or chronic obstructive pulmonary disease (COPD) may be involved in the pathogenesis of type 2 diabetes; however, prospective data have been limited.

METHODS

A prospective cohort of 38,570 women who were aged ≥ 45 years, free of cardiovascular disease and cancer at baseline, and free of diabetes at baseline and in the first 12 months were analyzed. We classified all women into three groups according to the presence and absence of self-reported asthma or COPD (including emphysema, chronic bronchitis, and bronchiectasis).

RESULTS

During a median follow-up of 12.2 years, 2472 incident type 2 diabetes events were documented. Women who had ever reported asthma or COPD were associated with an increased diabetes risk; the multivariate RRs were 1.37 (95% CI, 1.20-1.57) for women who had asthma alone and 1.38 (95% CI, 1.14-1.67) for COPD without asthmatic symptoms. Furthermore, these associations were not significantly modified by age, smoking status, physical activity, BMI, alcohol intake, hormone replacement therapy, menopausal status or randomized treatment.

CONCLUSIONS

Asthma and COPD were individually and independently associated with an increased risk of type 2 diabetes in women, indicating that chronic airway inflammation may contribute to diabetes pathogenesis.

Cigarette smoke activates NFκB-mediated Tnf-α release from mouse middle ear cells

OBJECTIVES/HYPOTHESIS

: Cigarette smoke exposure is a significant risk factor in the development of otitis media. NF-κB is a transcription factor known to mediate cigarette smoke effects in multiple cell types. We hypothesized that stimulation of murine middle ear epithelial cells (MEEC) with cigarette smoke condensate (CSC) activates NF-κB resulting in upregulation of proinflammatory cytokines.

STUDY DESIGN

: In vitro model of cultured murine middle ear epithelial cells.

METHODS

: Time course CSC stimulation of MEEC was performed. Antibody microarrays were then utilized to simultaneously measure 40 inflammatory cytokines. Enzyme-linked immunosorbent assay (ELISA) and quantitative reverse transcriptase-polymerase chain reaction were performed to validate and further evaluate array results. Luciferase reporter assays were performed to evaluate NF-κB activation with CSC in MEEC. Chromatin immunoprecipitation (ChIP) assays were performed to determine whether CSC induces NF-κB interaction with the Tnf-α promoter.

RESULTS

: Multiple cytokines showed significant increases with CSC exposure. ELISA studies demonstrated that Tnf-α secretion increased the most. CSC stimulation likewise increased Tnf-α mRNA abundance and induced promoter activity 4.8-fold in a Tnf-α reporter plasmid. Reporter assays demonstrated 4.84-fold activation of NF-κB with CSC. ChIP assays demonstrated NF-κB binding to canonical κB sites in the Tnf-α promoter with CSC stimulation.

CONCLUSIONS

: CSC activates NF-κB in MEEC. Furthermore, this activation results in CSC induced Tnf-α promoter activation, gene expression, and levels in cell secretions. Laryngoscope, 120:2508-2515, 2010.

NF-κB mediates IL-1β- and IL-17A-induced MUC5B expression in airway epithelial cells

A major pathological feature of chronic airway diseases is the elevated expression of gel-forming mucins. NF-κB activation in airway epithelial cells has been shown to play a proinflammatory role in chronic airway diseases; however, the specific role of NF-κB in mucin gene expression has not been characterized. In this study, we show that the proinflammatory cytokines, IL-1β and IL-17A, both of which use the NF-κB pathway, are potent inducers of MUC5B mRNA expression in both well differentiated primary normal human bronchial epithelial cells and the human bronchial epithelial cell line, HBE1. MUC5B induction by these cytokines was both time- and dose-dependent, and was attenuated by the small molecule inhibitor, NF-κB inhibitor III, as well as p65 small interfering RNA, suggesting that the regulation of MUC5B expression by these cytokines is via an NF-κB-based transcriptional mechanism. Deletion analysis of the MUC5B promoter demonstrated that IL-1β- and IL-17A-induced promoter activity resides within the -4.17-kb to -2.56-kb region relative to the transcriptional start site. This region contains three putative κB-binding sites (NF-κB-1, -3,786/-3,774; NF-κB-2, -3,173/-3,161; and NF-κB-3, -2,921/-2,909). Chromatin immunoprecipitation analysis confirmed enhanced binding of the p50 NF-κB subunit to the NF-κB-3 site after cytokine stimulation. We conclude that an NF-κB-based transcriptional mechanism is involved in MUC5B regulation by IL-1β and IL-17A in airway epithelium. This is the first demonstration of the participation of NF-κB and its specific binding site in cytokine-mediated airway MUC5B expression.

Effects of Lycopene, Indole-3-Carbinol, and Luteolin on Nitric Oxide Production and iNOS Expression are Organ-Specific in Rats

Natural compounds are known to modify NO content in tissues; however, the biological activity of polyphenol-rich food often does not correspond to the effects of individual polyphenols on NO synthase activity. The aim of this study was to see how natural compounds luteolin, indole-3-carbinol, and lycopene modify NO production in rat tissues and change the expression of the iNOS gene and protein. Indole-3-carbinol produced multiple effects on the NO level; it significantly decreased NO concentration in blood, lungs, and skeletal muscles and increased it in the liver. Indole-3-carbinol enhanced lipopolyssaccharide (LPS)-induced NO production in all rat organs. It decreased iNOS gene expression in the brain cortex of animals that did not receive LPS and up-regulated it in the LPS-treated animals. Lycopene increased the iNOS gene transcription rate in the brain cortex of LPS-treated animals. Luteolin did not modify NO production in any organ of LPS-untreated rats, nor did it affect gene expression in the liver. In the brain it slightly decreased iNOS gene expression. Luteolin decreased NO production in the blood of LPS-treated animals and the number of iNOS-positive cells in these animals. Our results suggest that changes in tissue NO levels caused by natural compounds cannot be predicted from their effect on NOS expression or activity obtained in model systems. This stresses the importance of direct measurements of NO and NOS expression in animal tissues.

Influence of metformin on GLUT1 gene and protein expression in rat streptozotocin diabetes mellitus model

CONTEXT

Metformin improves hyperglycaemia via mechanisms which include activation of AMP-activated protein kinase (AMPK). Recent findings indicate that some metabolic actions of metformin occur also by AMPK-independent mechanisms.

OBJECTIVE

To study the action of metformin on expression of GLUT1 glucose transporter in rat streptozotocin model of diabetes mellitus.

MATERIALS AND METHODS

Streptozotocin-induced rats were treated with metformin while monitoring parameters of carbohydrate and lipid metabolism. GLUT1 mRNA and protein expression in kidneys, heart, liver and muscles were studied by means of real time quantitative RT-PCR and immunohistochemistry correspondingly.

RESULTS

Metformin treatment decreased glucose concentration, glycated haemoglobin % and improved glucose tolerance. Streptozotocin diabetes provoked increase of both GLUT1 gene and protein expression in kidneys, metformin treatment produced normalization of the GLUT1 expression levels. In the liver, diabetes triggered an increase in GLUT1 protein expression, which was normalized by metformin.

CONCLUSION

Metformin is prospective for treatment of diabetic nephropathy.

Activation of hypoxia-inducible factor-1alpha via nuclear factor-kappa B in rats with chronic obstructive pulmonary disease

Accumulating data suggested that hypoxia inducible factor (HIF)-1alpha plays an important role in the evolution and propagation of the inflammatory process. To characterize the activation of HIF-1alpha in rats with chronic obstructive pulmonary disease (COPD) and examine the possible role of nuclear factor (NF)-kappaB in this process, rats were challenged by introtracheal instillation of lipopolysaccharide (LPS) and exposure to cigarette smoke. Pyrrolidine dithiocarbamate (PDTC) was administered via the oral route 1 h before LPS or cigarettes administration. Four weeks later, pulmonary function and histology were tested; bronchoalveolar lavage fluid (BALF) and arterial blood gases were assayed. Activation of pulmonary NF-kappaB was assessed by quantitative PCR, immunoblot analysis, and electrophoretic mobility shift assay, respectively. Results showed that LPS and smog induced the characteristics of COPD seen in human. PDTC alleviated the development of COPD and the levels of cytokines in BALF of PDTC+COPD group were significantly decreased compared with that of COPD group. The activation of pulmonary NF-kappaB was inhibited by PDTC and the accumulation of HIF-1alpha gene expression in the COPD group was attenuated by PDTC pretreatment. Furthermore, the mRNA levels of HIF-1alpha target genes heme oxygenase-1 (HO-1) and vascular endothelial growth factor (VEGF) were parallel to the attenuation of HIF-1alpha by PDTC. These findings indicated that the activation of HIF-1alpha pathway via NF-kappaB contributes to the development of COPD, and administration of NF-kappaB inhibitor may attenuate the development of COPD.

Overview of novel therapeutic targets for asthma and chronic obstructive pulmonary disease

Obstructive lung diseases, in particular asthma and chronic obstructive pulmonary disease, are a worldwide health problem that is increasing in incidence. While significant progress has been made in the control of symptoms, further advances must be made in modifying the clinical situation in terms of disease progression. Numerous pathogenetic studies have demonstrated that inflammatory responses play a crucial role in the development of chronic lung obstruction, while current molecular findings have provided a myriad of new and promising therapeutic targets. The aim of this article is to provide an overview of clinically and pharmacologically relevant targets for asthma and chronic obstructive pulmonary diseases, considering currently investigated therapeutic approaches.

Pathogenesis of pulmonary emphysema – cellular and molecular events

ABSTRACT Pulmonary emphysema is a chronic obstructive disease, resulting from important alterations in the whole distal structure of terminal bronchioles, either by enlargement of air spaces or by destruction of the alveolar wall, leading to loss of respiratory surface, decreased elastic recoil and lung hyperinflation. For many years, the hypothesis of protease-antiprotease unbalance prevailed as the central theme in the pathogenesis of pulmonary emphysema. According to this hypothesis, the release of active proteolytic enzymes, produced mainly by neutrophils and macrophages, degrades the extracellular matrix, affecting the integrity of its components, especially collagen and elastic fibers. However, new concepts involving cellular and molecular events were proposed, including oxidative stress, cell apoptosis, cellular senescence and failed lung tissue repair. The aim of this review paper was to evaluate the cellular and molecular mechanisms seen in the pathogenesis of pulmonary emphysema.

Inhaled corticosteroids and risk of pneumonia: evidence for and against the proposed association

Inhaled corticosteroids (ICS) are commonly used in the treatment of chronic obstructive pulmonary disease. Recent large prospective trials have reported an increased incidence of pneumonia in patients treated with ICS. Despite this, the link between ICS and pneumonia remains controversial. In this review, pro and con arguments for the association between ICS and increased pneumonia risk are discussed, drawing on evidence from experimental and clinical research.

Glutaredoxin 1 regulates cigarette smoke-mediated lung inflammation through differential modulation of I{kappa}B kinases in mice: impact on histone acetylation

Glutaredoxin 1 (Glrx1) is a small dithiol protein that regulates the cellular redox state and redox-dependent signaling pathways via modulation of protein glutathionylation. IkappaB kinase (IKK), an essential enzyme for NF-kappaB activation, can be subjected to S-glutathionylation leading to alteration of its activity. However, the role of Glrx1 in cigarette smoke (CS)-induced lung inflammation and chromatin modifications are not known. We hypothesized that Glrx1 regulates the CS-induced lung inflammation and chromatin modifications via differential regulation of IKKs by S-glutathionylation in mouse lung. Glrx1 knockout (KO) and wild-type (WT) mice were exposed to CS for 3 days and determined the role of Glrx1 in regulation of proinflammatory response in the lung. Neutrophil influx in bronchoalveolar lavage fluid and proinflammatory cytokine release in lung were increased in Glrx1 KO mice compared with WT mice exposed to CS, which was associated with augmented nuclear translocation of RelA/p65 and its phospho-acetylation. Interestingly, phosphorylated and total levels of IKKalpha, but not total and phosphorylated IKKbeta levels, were increased in lungs of Glrx1 KO mice compared with WT mice exposed to CS. Ablation of Glrx1 leads to increased CS-induced IKKbeta glutathionylation rendering it inactive, whereas IKKalpha was activated resulting in increased phospho-acetylation of histone H3 in mouse lung. Thus, targeted disruption of Glrx1 regulates the lung proinflammatory response via histone acetylation specifically by activation of IKKalpha in response to CS exposure. Overall, our study suggests that S-glutathionylation and phosphorylation of IKKalpha plays an important role in histone acetylation on proinflammatory gene promoters and NF-kappaB-mediated abnormal and sustained lung inflammation in pathogenesis of chronic inflammatory lung diseases.

Oxidative stress targets in pulmonary emphysema: focus on the Nrf2 pathway

IMPORTANCE OF THE FIELD

Oxidative stress has been implicated in the pathogenesis of pulmonary emphysema. Nuclear factor erythroid-2-related factor 2 (Nrf2) a major antioxidant transcription factor could play a protective role in pulmonary emphysema.

AREAS COVERED IN THIS REVIEW

Nrf2 is ubiquitously expressed throughout the lung, but is predominantly found in epithelium and alveolar macrophages. Evidence suggests that Nrf2 and several Nrf2 downstream genes have an essential protective role in the lung against oxidative stress from environmental pollutants and toxicants such as cigarette smoke, a major causative factor for the development and progression of pulmonary emphysema. Application of Nrf2-deficient mice identified an extensive range of protective roles for Nrf2 against the pathogenesis of pulmonary emphysema. Therefore, Nrf2 promises to be an attractive therapeutic target for intervention and prevention strategies.

WHAT THE READER WILL GAIN

In this review, we discuss recent findings on the association of oxidative stress with pulmonary emphysema. We also address the mechanisms of Nrf2 lung protection against oxidative stress based on emerging evidence from experimental oxidative disease models and human studie.

TAKE HOME MESSAGE

The current literature suggests that among oxidative stress targets, Nrf2 is a valuable therapeutic target in pulmonary emphysema.