Molecular mechanisms of the impact of smoke-oxidants

Role of thioredoxin in chronic obstructive pulmonary disease (COPD): a promising future target

INTRODUCTION

Thioredoxin (Trx) is a secretory protein that acts as an antioxidant, redox regulator, anti-allergic, and anti-inflammatory molecule. It has been used to treat dermatitis and inflammation of the digestive tract. In the lungs, Trx has a significant anti-inflammatory impact. On the other hand, Chronic Obstructive Pulmonary Disease (COPD) is one of the significant causes of death in the developed world, with a tremendous individual and socioeconomic impact. Despite new initiatives and endless treatment trials, COPD incidence and death will likely escalate in the coming decades.

AREAS COVERED

COPD is a chronic inflammatory disease impacting the airways, lung parenchyma, and pulmonary vasculature. Oxidative stress and protease-antiprotease imbalances are thought to be involved in the process. The most popular respiratory inflammatory and allergic disorders therapies are corticosteroids and β-receptor agonists. These medications are helpful but have some drawbacks, such as infection and immunosuppression; thus, addressing Trx signalling treatments may be a viable COPD treatment approach. This review shall cover the pathophysiology of COPD, the pharmacognosy of anti-COPD drugs, including the assets and liabilities of each, and the role and mechanism of Trx in COPD treatment.

EXPERT OPINION

Limited research has targeted the thioredoxin system as an anti-COPD drug. Spectating the increase in the mortality rates of COPD, this review article would be an interesting one to research.

Mucus Hypersecretion in Chronic Obstructive Pulmonary Disease and Its Treatment

Most patients diagnosed with chronic obstructive pulmonary disease (COPD) present with hallmark features of airway mucus hypersecretion, including cough and expectoration. Airway mucus function as a native immune system of the lung that severs to trap particulate matter and pathogens and allows them to clear from the lung via cough and ciliary transport. Chronic mucus hypersecretion (CMH) is the main factor contributing to the increased risk of morbidity and mortality in specific subsets of COPD patients. It is, therefore, primarily important to develop medications that suppress mucus hypersecretions in these patients. Although there have been some advances in COPD treatment, more work remains to be done to better understand the mechanism underlying airway mucus hypersecretion and seek more effective treatments. This review article discusses the structure and significance of mucus in the lungs focusing on gel-forming mucins and the impacts of CMH in the lungs. Furthermore, we summarize the article with pharmacological and nonpharmacological treatments as well as novel and interventional procedures to control CMH in COPD patients.

Early-life exposure to tobacco smoke alters airway signaling pathways and later mortality in D. melanogaster

Early life environmental influences such as exposure to cigarette smoke (CS) can disturb molecular processes of lung development and thereby increase the risk for later development of chronic respiratory diseases. Among the latter, asthma and chronic obstructive pulmonary disease (COPD) are the most common. The airway epithelium plays a key role in their disease pathophysiology but how CS exposure in early life influences airway developmental pathways and epithelial stress responses or survival is poorly understood. Using Drosophila melanogaster larvae as a model for early life, we demonstrate that CS enters the entire larval airway system, where it activates cyp18a1 which is homologues to human CYP1A1 to metabolize CS-derived polycyclic aromatic hydrocarbons and further induces heat shock protein 70. RNASeq studies of isolated airways showed that CS dysregulates pathways involved in oxidative stress response, innate immune response, xenobiotic and glutathione metabolic processes as well as developmental processes (BMP, FGF signaling) in both sexes, while other pathways were exclusive to females or males. Glutathione S-transferase genes were further validated by qPCR showing upregulation of gstD4, gstD5 and gstD8 in respiratory tracts of females, while gstD8 was downregulated and gstD5 unchanged in males. ROS levels were increased in airways after CS. Exposure to CS further resulted in higher larval mortality, lower larval-pupal transition, and hatching rates in males only as compared to air-exposed controls. Taken together, early life CS induces airway epithelial stress responses and dysregulates pathways involved in the fly's branching morphogenesis as well as in mammalian lung development. CS further affected fitness and development in a highly sex-specific manner.

Association of Genetic Variants in IL6 Gene (rs1800795) with the Concentration of Inflammatory Markers (IL-6, hs-CRP) and Superoxide Dismutase in the Blood of Patients with Acute Pancreatitis—Preliminary Findings

In the course of acute pancreatitis, interleukin-6 plays an important role as a mediator in the inflammatory response. The course of inflammatory disease is associated with intensive oxidative stress, which may activate transcription factors leading to gene-expression changes. Isoenzymes of superoxide dismutase are involved in the defense against free radicals. This study aimed to evaluate changes in IL-6 concentration and the concentration/activity of superoxide dismutase isoenzymes (SOD1, SOD2, and SOD3) in the blood of patients with acute pancreatitis (AP) in terms of rs1800795 polymorphism in the IL6 gene. In the smoking AP patients group with the GC and GG genotypes, the plasma SOD1 concentration was significantly higher (p = 0.0146 and p = 0.0250, respectively) than in patients with CC genotype for SNP rs1800795 in the IL6 gene. An increase in SOD1 concentration in erythrocytes of AP patients with GC genotypes was also demonstrated compared to the individuals from the group with GG genotype (p = 0.0408). Furthermore, a positive correlation between IL-6 and SOD1 concentrations in the plasma of AP patients with GC genotype for SNP rs1800795 was shown. These results indicate that SOD1 may play a protective role against oxidative damage induced by inflammation in the group of AP patients with GC genotype.

Activity of glutathione S-transferase and its π isoenzyme in the context of single nucleotide polymorphism in the GSTP1 gene (rs1695) and tobacco smoke exposure in the patients with acute pancreatitis and healthy subjects

Oxidative stress associated with the course of acute pancreatitis (AP) can cause changes in the involvement of antioxidants, which can result in the increased production of free radicals with pro-inflammatory potential. Through its noncatalytic activity, the glutathione S-transferase and its π isoenzyme (GST-π), apart from cellular xenobiotics detoxification, are involved in the regulation of cellular signalling, metabolism and apoptosis. This study aimed to evaluate the impact of SNP rs1695 in the GSTP1 gene on GST and GST-π activity in healthy subjects and patients with acute pancreatitis (AP). The concentration of glutathione (GSH) as an important component of the antioxidant system, necessary for environmental xenobiotics detoxification by GST, and malonyldialdehyde (MDA) as a marker of oxidative stress induced by inflammation were also assessed. SNP was examined in 39 AP patients and 51 healthy subjects using PCR-RFLP methods. GST activity (in plasma and erythrocyte lysate) and GST-π activity (in erythrocyte lysate) were measured using the spectrophotometric method with 1-chloro-2,4-dinitrobenzene and ethacrynic acid as substrate, respectively. Blood GSH concentration was measured using the Patterson method. Concentrations of high-sensitive C-reactive protein (hs-CRP) and MDA were measured using commercial tests. In the blood of non-smoking AP patients with GG genotypes for SNP rs1695 in the GSTP1 gene, the lowest GST-π activity was shown. It was accompanied by the lowest hsCRP concentration in this group. In the blood of smoking healthy subjects with AG genotype, a decrease in GST-π activity was noted compared to non-smokers from this group. However, in the blood of smokers with AP, a gradually decreasing GST-π activity was noted in individuals with AA genotype, which was associated with the increasing MDA concentration. It confirms the role of GST-π in the neutralization of oxidative stress induced by the exposure to smoke xenobiotics.

Importance of Genetic Polymorphisms in MT1 and MT2 Genes in Metals Homeostasis and Their Relationship with the Risk of Acute Pancreatitis Occurrence in Smokers-Preliminary Findings

This study was aimed at evaluating the changes in metallothionein (MT) concentration in the blood of patients with acute pancreatitis (AP) and healthy subjects, taking into account the extracellular (plasma) and intracellular (erythrocyte lysate) compartments. The impact of single-nucleotide polymorphisms (SNPs) in the MT1A (rs11640851), MT1B (rs964372) and MT2A (rs10636) genes on MT concentration and their association with the concentration of metals (Cu, Zn, Cd) and ceruloplasmin as Cu-related proteins were analyzed. The concentration of a high-sensitivity C-reactive protein (hs-CRP) and IL-6 as markers of inflammation, and malonyldialdehyde (MDA), superoxide dismutase (SODs) activity and the value of total antioxidant capacity (TAC) as parameters describing the pro/antioxidative balance were also assessed. In the AP patient groups, an increased MT concentration in erythrocyte lysate compared to healthy subjects was shown, especially in individuals with the GG genotype for rs964372 in the MT1B gene. A Zn concentration was especially decreased in the blood of smoking AP patients with the AA genotype for SNP rs11640851 in the MT1A gene and the GC genotype for SNP rs10636 in MT2A, compared to non-smokers with AP, which was accompanied by an increase in the value of the Cu/Zn ratio. The exposure to tobacco smoke xenobiotics increased the risk of AP occurrence in subjects with the CC genotype for SNP rs11640851 in the MT1A gene by more than fourfold. The investigated polymorphisms, rs11640851 in the MT1A gene, rs964372 in the MT1B gene and rs10636 in the MT2A gene, seem to be an important factor in maintaining homeostasis in an organism under oxidative stress conditions.

Second-hand smoke and NFE2L2 genotype interaction increases paediatric asthma risk and severity

BACKGROUND

Second-hand smoke (SHS) exposure is associated with paediatric asthma, and oxidative stress is believed to play a role in mediating this association. The nuclear factor (erythroid-derived 2)-like 2 (NFE2L2) is important for the defence against oxidative stress.

OBJECTIVE

To explore interactions between NFE2L2 genotype and SHS exposure in paediatric asthma risk.

METHODS

We used a genotyped subset of patients of European ancestry (N = 669, median age at enrolment = 6.8 years) enrolled in the clinical cohort Greater Cincinnati Pediatric Clinic Repository as the study population, and a population-based paediatric cohort (N = 791) to replicate our findings. History of asthma diagnosis was obtained from medical records, and SHS exposure was obtained from questionnaires. Four NFE2L2 tagging SNPs were included in the analysis, and interactions between SHS and NFE2L2 genotype were evaluated using logistic regression.

RESULTS

Three of the analysed SNPs, rs10183914, rs1806649 and rs2886161, interacted significantly with SHS exposure to increase asthma risk (p ≤ .02). The interaction was replicated in an independent cohort for rs10183914 (p = .04). Interactions between SHS exposure and NFE2L2 genotype were also associated with an increased risk of hospitalization (p = .016). In stratified analyses, NFE2L2 genotype was associated with daily asthma symptoms in children with SHS exposure (OR = 3.1; p = .048). No association was found in children without SHS exposure. Examination of publicly available chromatin immunoprecipitation followed by sequencing (ChIP-seq) data sets confirmed the presence of active histone marks and binding sites for particular transcription factors overlapping the coordinates for the significantly associated SNPs.

CONCLUSIONS AND CLINICAL RELEVANCE

Our study provides evidence that NFE2L2 genotype interacts with SHS exposure to affect both asthma risk and severity in children and identifies a population of children at increased risk of asthma development.

Lipid Peroxidation, GSH Depletion, and SLC7A11 Inhibition Are Common Causes of EMT and Ferroptosis in A549 Cells, but Different in Specific Mechanisms

Epithelial-mesenchymal transition (EMT) induced by transforming growth factor-β1 (TGF-β1) is thought to be involved in the pathogenesis of pulmonary fibrosis. Emerging evidence suggested that there are some common causes between ferroptosis and pulmonary fibrosis. The interaction of EMT and ferroptosis and its mechanism were investigated by detecting the expression levels of α-smooth muscle actin (α-SMA), E-cadherin, solute carrier family 7 member 11 (SLC7A11), and glutathione peroxidase 4 (GPX4) and measuring the contents of reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione (GSH). The cellular morphology and ultrastructure of mitochondria were studied by microscope and transmission electron microscope (TEM), respectively. The results showed that ferroptosis in A549 cells was induced by Erastin, which decreased the expression levels of E-cadherin (E-Ca), α-SMA, and SLC7A11, accompanied with ROS and MDA increase, as well as GSH decrease. TGF-β1 promoted ultrastructure variation of mitochondria similar to ferroptosis and mesenchymal changes in morphology during EMT of A549 cells, accompanied with reduced GSH content and expression of SLC7A11, as well as ROS and MDA increase. Ferrostatin-1 (Fer-1) recovered ferroptosis induced by Erastin, but had no effect on the morphological change caused by TGF-β1. Furthermore, Fer-1 reduced ROS and MDA production, and increased SLC7A11 expression in the early subsequently increased GSH. However, the effects of Fer-1 on above indicators were different in time. The expression of GPX4 had no significant change during EMT induced by TGF-β1 and ferroptosis induced by Erastin in A549 cells. It is indicating that Erastin promoted the de-epithelialization of lung epithelial cells, but inhibited the process of myofibroblast differentiation; Fer-1 could partially inhibit EMT induced by TGF-β1, but reverse ferroptosis induced by Erastin. TGF-β1 could delay the ferroptosis, but could not prevent it. Lipid peroxidation, GSH depletion, and SLC7A11 inhibition are common causes of EMT and ferroptosis in A549 cells, but different in specific mechanisms. The exact effects of GPX4 involved in EMT and ferroptosis in A549 cells need further study.

Increased risk of acute pancreatitis occurrence in smokers with rs5751901 polymorphisms in GGT1 gene

Objectives: The study was aimed to assess γ‑glutamyltransferase (GGT) activity and concentration as a marker of oxidative stress induced by exposure to tobacco smoke in acute pancreatitis (AP) course. Examination of the relationship between GGT activity/concentration and single-nucleotide polymorphism (SNP rs5751901 and rs2236626) in GGT1 gene was performed. Subjects and methods: We examined SNPs in 38 AP patients and 51 healthy subjects by PCR-RFLP methods. GGT concentration in blood was measured with the use of the ELISA method; GGT activity and GSH concentration were measured by the Szasz and Patterson methods, respectively. Results: In the non-AP smokers group with TC genotype for SNPrs5751901 an increased blood GGT activity compared to smokers with CC genotypes was shown. In the course of AP was observed an elevated GGT activity and the value of GGT activity/GGT concentration ratio in smokers compared to non-smokers, in AP patients with TC genotypes and CC genotypes, respectively, for both SNP: rs5751901 and rs2236626. In the group of smoking AP patients with the CC and TC genotypes in rs5751901 locus and CC and TT genotypes in rs2236626 locus a decreases in GSH concentration during hospitalization were noted. Conclusions: SNP rs5751901 and rs2236626 cause changes in GGT activity. Smoking in the AP course contributes to increased GGT activity and excessive GSH use up in patients with TC and CC genotypes for both SNPs. Exposure to smoke xenobiotics enhances (3-fold) the risk of AP occurrence in individuals with TC genotypes for SNP rs5751901.

Decreases in Paraoxonase-1 Activities Promote a Pro-inflammatory Effect of Lipids Peroxidation Products in Non-smoking and Smoking Patients with Acute Pancreatitis

Aim: The study investigated the extent to which tobacco smoke exposure causes changes in lipids biochemistry through measurement blood concentrations of: paraoxonase-1 (PON-1) activities as lipid-bound enzyme into cell membrane, concentration of malonyldialdehyde (MDA), protein adducts of 4-hydroxynonenal (HNE-adducts), oxidized low density lipoproteins (oxLDL), total cholesterol (CH) and high-density lipoprotein cholesterol (HDL). Additionally, the activity of P isoform of glutathione S-transferase (GST-π) was measured. Methods: Investigations were performed in the blood of patients with acute pancreatitis (AP) on the 1st, 3rd and 7th day of hospitalization and in healthy volunteers. The activities of PON-1 forms, GST-π were determined spectrophotometrically. Concentrations of PON-1, MDA, HNE-adducts, oxLDL, HDL, CH were measured using commercial tests. Results: Near 2-fold higher concentrations of MDA, HNE-adducts, oxLDL, correlating with inflammatory markers in AP patients compared to healthy subjects were demonstrated, which were accompanied by gradually increasing CH/HDL ratio during hospitalization. During hospital treatment, decreased activities of all PON-1 subtypes were observed in AP patients compared to healthy subjects, more pronounced in tobacco smokers. A decreased PON-1 phosphotriesterase activity in non-AP control group smokers compared to non-smokers was noted. In non-smoking AP patients GST-π activity normalized during hospitalization in contrast to smokers. Conclusions: GST-π and PON-1 phosphotriesterase activities seem to be a sensitive marker of pro/antioxidative imbalance in smokers. Lipids peroxidation products generated during AP can intensify preexisting inflammation. Increasing stay in the hospital was associated with worsening of lipids peroxidation markers and the parameters of lipid profile, in both non-smoking and smoking AP patients, what can indicate that the oxidative-inflammatory process are not extinguished.

Caryophyllane sesquiterpenes inhibit DNA-damage by tobacco smoke in bacterial and mammalian cells

In the present study, the ability of the natural sesquiterpene β-caryophyllene (CRY) and its metabolite β-caryophyllene oxide (CRYO) to inhibit the genotoxicity of a condensate of cigarette smoke (CSC) was evaluated both in bacterial and mammalian cells. Also, the inhibition of the CSC-mediated STAT3 phosphorylation and intracellular oxidative stress was evaluated as potential chemopreventive mechanism. Under our experimental conditions, both the sesquiterpenes exhibited antimutagenic properties, being CRY the most potent compound. The antimutagenicity was highlighted in all experimental protocols, being particularly strong in the co- and post-treatments. The test substances also reduced the micronuclei frequency induced by CSC, with a major effectiveness of CRY. CRY was also able to reduce the CSC-mediated increase of the Y705- pSTAT3 levels, in spite of a lacking effect of CRYO. Furthermore, the sesquiterpenes CRY and CRYO displayed a moderate antioxidant activity, with a 25 % and 40 % inhibition of the ROS-levels increased by CSC, respectively. On the basis of these results, CRY seems to be a multi-target chemopreventive agent, although the genoprotective and antioxidant effects of CRYO suggest that both compounds deserve to be deeply investigated for a possible application in the prevention and treatment of different smoke-related ailments.

Phenolic Melatonin-Related Compounds: Their Role as Chemical Protectors against Oxidative Stress

There is currently no doubt about the serious threat that oxidative stress (OS) poses to human health. Therefore, a crucial strategy to maintain a good health status is to identify molecules capable of offering protection against OS through chemical routes. Based on the known efficiency of the phenolic and melatonin (MLT) families of compounds as antioxidants, it is logical to assume that phenolic MLT-related compounds should be (at least) equally efficient. Unfortunately, they have been less investigated than phenols, MLT and its non-phenolic metabolites in this context. The evidence reviewed here strongly suggests that MLT phenolic derivatives can act as both primary and secondary antioxidants, exerting their protection through diverse chemical routes. They all seem to be better free radical scavengers than MLT and Trolox, while some of them also surpass ascorbic acid and resveratrol. However, there are still many aspects that deserve further investigations for this kind of compounds.