Apoptosis and necrosis: two different outcomes of cigarette smoke condensate-induced endothelial cell death

Assessment of toxicological validity using tobacco emission condensates: A comparative analysis of emissions and condensates from 3R4F reference cigarettes and heated tobacco products

The tobacco emission condensate, henceforth referred to as "tobacco condensate," plays a critical role in assessing the toxicity of tobacco products. This condensate, derived from tobacco emissions, provides an optimized liquid concentrate for storage and concentration control. Thus, the validation of its constituents is vital for toxicity assessments. This study used tobacco condensates from 3R4F cigarettes and three heated tobacco product (HTP) variants to quantify and contrast organic compounds (OCs) therein. The hazard index (HI) for tobacco emissions and condensates was determined to ascertain the assessment validity. The total particulate matter (TPM) for 3R4F registered at 17,667 μg cig-1, with its total OC (TOC) at 3777 μg cig-1. HTPs' TPM and TOC were 9342 ± 1918 μg cig-1 and 5258 ± 593 μg stick-1, respectively. 3R4F's heightened TPM likely arises from tar, while HTPs' OC concentrations are influenced by vegetable glycerin (2236-2688 μg stick-1) and propylene glycol (589-610 μg stick-1). During the condensation process, a substantial proportion of OCs in 3R4F smoke underwent significant concentration decreases, in contrast to HTPs, where fewer than half of the examined OCs exhibited notable concentration declines. The HI for tobacco emissions exhibited a marginally higher value compared to tobacco condensate, with variations ranging from 7.92% (HTPs) to 18.6% (3R4F), denoting a minimal differential. These observations emphasize the importance of accurate OC recovery techniques to maintain the validity and reliability of toxicity assessments based on tobacco condensates. This study not only deepens the comprehension of chemical behaviors in tobacco products but also establishes a novel benchmark for their toxicity evaluation, with profound implications for public health strategies and consumer protection.

The Antioxidant, Antibacterial and Cell-Protective Properties of Bioactive Compounds Extracted from Rowanberry (Sorbus aucuparia L.) Fruits In Vitro

Considering that Sorbus aucuparia fruits have been underutilized despite their tremendous potential, this study aimed to correlate the in vitro antioxidant, antibacterial and cell-protective abilities of fruit extracts derived from Sorbus aucuparia Romanian cultivars with their phytochemical composition. Therefore, following the preparation of ethanolic and carotenoid extracts, phytochemical screening was performed using UV-Vis and HPLC-DAD-ESI-MS methods. The antioxidant activity was analyzed using DPPH and FRAP tests. As the results revealed high contents of bioactive compounds (polyphenols 1.11 mg GAE/g DM, flavonoids 430.06 µg QE/g DM and carotenoids 95.68 µg/g DM) and an important antiradical action (DPPH 24.51 mg/mL and FRAP 0.016 µM TE/mL), we chose to further examine the fruits' biological properties. The antibacterial capacity was assessed employing agar well diffusion and broth microdilution techniques, with fruits displaying an intense activity against MSSA, MRSA and Enterococcus faecalis, but also E. coli and Pseudomonas aeruginosa. The cell-protective activity was analyzed on gentamicin-stressed renal cells, through MTT and Annexin V-FITC assays. Importantly, a significant increase in viability was registered on stressed cells following extract administration in low doses; nevertheless, viability was noticed to decline when exposed to elevated concentrations, potentially due to the cumulative actions of the extract and gentamicin. These findings offer novel light on the antibacterial activity of Sorbus aucuparia Romanian cultivars, as well as their cell-protective ability in renal cell injury.

Tobacco toxins induce osteoporosis through ferroptosis

Clinical epidemiological studies have confirmed that tobacco smoking disrupts bone homeostasis and is an independent risk factor for the development of osteoporosis. The low viability and inferior osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) are important etiologies of osteoporosis. However, few basic studies have elucidated the specific mechanisms that tobacco toxins devastated BMSCs and consequently induced or exacerbated osteoporosis. Herein, our clinical data showed the bone mineral density (BMD) values of femoral neck in smokers were significantly lower than non-smokers, meanwhile cigarette smoke extract (CSE) exposure led to a significant decrease of BMD in rats and dysfunction of rat BMSCs (rBMSCs). Transcriptomic analysis and phenotype experiments suggested that the ferroptosis pathway was significantly activated in CSE-treated rBMSCs. Accumulated intracellular reactive oxygen species activated AMPK signaling, furtherly promoted NCOA4-mediated ferritin-selective autophagic processes, increased labial iron pool and lipid peroxidation deposition, and ultimately led to ferroptosis in rBMSCs. Importantly, in vivo utilization of ferroptosis and ferritinophagy inhibitors significantly alleviated BMD loss in CSE-exposed rats. Our study innovatively reveals the key mechanism of smoking-related osteoporosis, and provides a possible route targeting on the perspective of BMSC ferroptosis for future prevention and treatment of smoking-related bone homeostasis imbalance.

Comparative assessment of electronic nicotine delivery systems aerosol and cigarette smoke on endothelial cell migration: The Replica Project

Cigarette smoking is associated with impairment of repair mechanisms necessary for vascular endothelium homeostasis. Reducing the exposure to smoke toxicants may result in the mitigation of the harmful effect on the endothelium and cardiovascular disease development. Previous investigations evaluated in vitro the effect of electronic cigarette (EC) compared with cigarette smoke demonstrating a significant reduction in human umbilical vein endothelial cells (HUVECs) migration inhibition following EC aerosol exposure. In the present study, we replicated one of these studies, evaluating the effects of cigarette smoke on endothelial cell migration compared with aerosol from EC and heated tobacco products (HTPs). We performed an in vitro scratch wound assay on endothelial cells with a multi-center approach (ring-study) to verify the robustness and reliability of the results obtained in the replicated study, also testing the effect of aerosol from two HTPs on endothelial cells. Consistently with the original study, we observed a substantial reduction of the effects of aerosol from EC and HTPs on endothelial cell migration compared with cigarette smoke. While cigarette smoke reduced endothelial wound healing ability already at low concentrations (12.5%) and in a concentration-dependent manner, EC and HTPs aerosol showed no effect on endothelial cells until 80%-100% concentrations. In conclusion, our study further confirms the importance of EC and tobacco heated products as a possible harm reduction strategy for cardiovascular diseases development in smokers.

Cigarette smoking exposure disrupts the regenerative potential of dental pulp stem cells

INTRODUCTION

Smoking is known to alter the regenerative and immunomodulatory properties of many types of mesenchymal stem cells (MSCs). This study investigates the impact of cigarette smoke exposure on the regenerative potential of dental pulp stem cells (DPSCs).

METHODS

DPSCs were treated with various doses of cigarette smoke condensate (CSC) or nicotine. Cell proliferation and survival were evaluated by a water-soluble tetrazolium salt (WST-1) and a survival assay. DPSC migration, cytokine expression, mutagenesis, and the signaling pathway were also measured during CSC and nicotine treatment.

RESULTS

Low concentrations of CSC and nicotine did not impair cell proliferation, but higher concentrations reduced cell proliferation. CSC and nicotine could impede DPSC survival and migration in a dose-dependent manner. In addition, the cytokine secretion expression profile was altered with CSC or nicotine treatments. In particular, secretion of IL-6, TNF-α, and IL-10 significantly increased, while TGF-β1 levels showed different patterns after exposure to CSC or nicotine, as shown by ELISA and quantitative PCR. Nicotine treatment increased AKT (also known as protein kinase B) and extracellular signal-regulated kinase (ERK) phosphorylation. Finally, CSC induced higher levels of mutagenicity than nicotine, as shown by the Ames test.

CONCLUSIONS

These findings suggest that cigarette smoke exposure alters the regenerative abilities of DPSCs in various ways. Future studies are warranted to further characterize the underlying molecular mechanisms of smoking-mediated damage to DPSCs, which will guide the personalized stem cell treatment plan for smoking patients.

Gene Set Based Integrated Methylome and Transcriptome Analysis Reveals Potential Molecular Mechanisms Linking Cigarette Smoking and Related Diseases

Advanced integrative analysis of DNA methylation and transcriptomics data may provide deeper insights into smoke-induced epigenetic alterations, their effects on gene expression and related biological processes, linking cigarette smoking and related diseases. We hypothesize that accumulation of DNA methylation changes in CpG sites across genomic locations of different genes might have biological significance. We tested the hypothesis by performing gene set based integrative analysis of blood DNA methylation and transcriptomics data to identify potential transcriptomic consequences of smoking via changes in DNA methylation in the Young Finns Study (YFS) participants (n = 1114, aged 34-49 years, women: 54%, men: 46%). First, we performed epigenome-wide association study (EWAS) of smoking. We then defined sets of genes based on DNA methylation status within their genomic regions, for example, sets of genes containing hyper- or hypomethylated CpG sites in their body or promoter regions. Gene set analysis was performed using transcriptomics data from the same participants. Two sets of genes, one containing 49 genes with hypomethylated CpG sites in their body region and the other containing 33 genes with hypomethylated CpG sites in their promoter region, were differentially expressed among the smokers. Genes in the two gene sets are involved in bone formation, metal ion transport, cell death, peptidyl-serine phosphorylation, and cerebral cortex development process, revealing epigenetic-transcriptomic pathways to smoking-related diseases such as osteoporosis, atherosclerosis, and cognitive impairment. These findings contribute to a deeper understanding of the pathophysiology of smoking-related diseases and may provide potential therapeutic targets.

Cigarette tar mediates macrophage ferroptosis in atherosclerosis through the hepcidin/FPN/SLC7A11 signaling pathway

Despite the known promotional effects of cigarette smoking on progression of atherosclerosis (AS), tar as the most dominant toxic component in cigarette smoking has been little studied. Understanding the potential role and mechanisms of tar in AS may be a prerequisite for future reductions in cardiovascular morbidity and mortality. Male ApoE^-/- mice were fed with high-fat diet and injected intraperitoneally with cigarette tar (40 mg/kg/day) for 16 weeks. The results showed that cigarette tar significantly promoted the formation of lipid-rich plaques with larger necrotic cores and less fibrous, and caused severe iron overload and lipid peroxidation in AS lesions. Moreover, tar significantly upregulated the expression of hepcidin and downregulated FPN and SLC7A11 of macrophages in AS plaques. Ferroptosis inhibitor (FER-1 and DFO) treatment, hepcidin-knockdown or SLC7A11-overexpression reversed above changes, thereby delaying the progression of atherosclerosis. In vitro, the use of FER-1, DFO, si-hepcidin, and ov-SLC7A11 increased cell viability and inhibited iron accumulation, lipid peroxidation and GSH depletion in tar treated macrophages. These interventions also inhibited the tar induced upregulation of hepcidin, and increased the expression of FPN, SLC7A11, and GPX4. Furthermore, NF-κB inhibitor reversed the regulatory effect of tar on hepcidin/FPN/SLC7A11 axis, and then inhibiting macrophage ferroptosis. These findings indicated that cigarette tar promotes atherosclerosis progression by inducing macrophage ferroptosis via NF-κB-activated hepcidin/FPN/SLC7A11 pathway.

Cigarette Smoke Extract Induces p38 MAPK-Initiated, Fas-Mediated Eryptosis

Eryptosis is a physiological mechanism for the clearance of senescent or damaged erythrocytes by phagocytes. Excessive eryptosis is stimulated under several pathologies and associated with endothelial injury and thrombosis. Cigarette smoke (CS) is an established risk factor for vascular diseases and cigarette smokers have high-levels of eryptotic erythrocytes. This study, for the first time, investigates the mechanism by which CS damages red blood cells (RBCs). CS extract (CSE) from commercial cigarettes was prepared and standardized for nicotine content. Cytofluorimetric analysis demonstrated that treatment of human RBCs with CSE caused dose-dependent, phosphatidylserine externalization and cell shrinkage, hallmarks of apoptotic death. CSE did not affect cellular levels of Ca²⁺, reactive oxygen species (ROS) or glutathione (GSH). Immununoprecipitation and immunoblotting revealed the assembly of the death-inducing signaling complex (DISC) and oligomerization of Fas receptor as well as cleaved caspase-8 and caspase-3 within 6 h from the treatment. At the same time-interval, CSE elicited neutral sphyngomielinase (nSMase) activity-dependent ceramide formation and phosphorylation of p38 MAPK. Through specific inhibitors' nSMase, caspase-8 or p38 MAPK activities, we demonstrated that p38 MAPK activation is required for caspase-8-mediated eryptosis and that ceramide generation is initiator caspase-dependent. Finally, ex vivo analysis detected phosphorylated p38 MAPK (p-p38) and Fas-associated signaling complex in erythrocytes from cigarette smokers. In conclusion, our study demonstrates that CSE exposure induces in erythrocytes an extrinsic apoptotic pathway involving p38 MAPK-initiated DISC formation followed by activation of caspase-8/caspase-3 via ceramide formation.

Targeting the alternative oxidase (AOX) for human health and food security, a pharmaceutical and agrochemical target or a rescue mechanism?

Some of the most threatening human diseases are due to a blockage of the mitochondrial electron transport chain (ETC). In a variety of plants, fungi, and prokaryotes, there is a naturally evolved mechanism for such threats to viability, namely a bypassing of the blocked portion of the ETC by alternative enzymes of the respiratory chain. One such enzyme is the alternative oxidase (AOX). When AOX is expressed, it enables its host to survive life-threatening conditions or, as in parasites, to evade host defenses. In vertebrates, this mechanism has been lost during evolution. However, we and others have shown that transfer of AOX into the genome of the fruit fly and mouse results in a catalytically engaged AOX. This implies that not only is the AOX a promising target for combating human or agricultural pathogens but also a novel approach to elucidate disease mechanisms or, in several cases, potentially a therapeutic cure for human diseases. In this review, we highlight the varying functions of AOX in their natural hosts and upon xenotopic expression, and discuss the resulting need to develop species-specific AOX inhibitors.

Testing efficacy of the nicotine protection of the substantia nigra pars compacta in a rat Parkinson disease model. Ultrastructure study

Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) with subsequent motor manifestations. This study aimed to assess the ameliorative effects of nicotine, in rotenone-induced PD rat model. Thirty adult male Albino Wistar rats were divided into three equal groups. Group I received an injection of normal saline. Group II received subcutaneous injection of rotenone at a dose of 1.5 mg/kg every other day. Group III received rotenone in the same previous dose and nicotine at a dose of 1.5 mg/kg daily. After 11 days of treatment, body weight (BW) and rat motor behavior were estimated. Specimens from the midbrain were processed for light and electron microscopy. The expression of tyrosine hydroxylase (TH), α-synuclein, and GFAP was examined. Serum levels of total antioxidant capacity (TAC) and malondialdehyde (MDA), and striatal levels of dopamine (DA) were analyzed. Group III revealed a significant improvement in BW and motor activity. Nicotine upregulated the expression of TH, downregulated the expression of α-synuclein and GFAP. The levels of MDA and TAC were improved but were still far from those of the control. Striatal DA levels increased. Nicotine activated the neurons and glial cells. The vascular endothelium, however, did not elicit improvement. Although nicotine ameliorated the loss of the dopaminergic neurons and motor deficit, it did not show improvement of vascular endothelium. It is still necessary to examine nicotin's ability to maintain the dopaminergic neurons in a good functioning state.

Environmental dose of 16 priority-controlled PAHs mixture induce damages of vascular endothelial cells involved in oxidative stress and inflammation

Epidemiological studies have shown that cardiovascular diseases caused by PM_2.5 pollution account for the second death rate in China. Polycyclic aromatic hydrocarbons (PAHs) are one important group of persistent organic pollutants absorbed on PM_2.5. Though individual PAH is related to vascular disease, the relationship between environmental PAHs exposure and vascular damages is still unclear. To explore the effect of PAHs on blood vessel, human umbilical vein endothelial cells (HUVECs) are treated with 16 priority-controlled PAHs at various concentrations to study their cytotoxicity and morphological alteration. Results showed that, after 48 h treatment, PAHs mixture generally attenuated the ability of wound healing, transwell migration and tube formation of HUVECs (p < 0.01) except for 1 × PAHs in transwell migration. Moreover, PAHs increased the levels of ROS and 8-hydroxy-2'-deoxyguanosine (p < 0.05), indicating that it exceeded the scavenging ability of superoxide dismutase activity. However, PAHs mixture did not increase apoptosis rate, which may be attribute to the difference of PAH concentration and composition between this study and previous reports. Downstream signaling cascades significantly and generally upregulated the relative expression of proteins in Nrf2/HO-1 and NF-ƙB/TNF-α pathway with the activation of oxidative stress, including HO-, TNF-α and Nrf2. In summary, this study suggests that environmental mixture of 16 priority-controlled PAHs can induce the damages of vascular endothelial cells involved in cellular oxidative stress and inflammation.

Cortactin Modulates Lung Endothelial Apoptosis Induced by Cigarette Smoke

Cigarette smoke (CS) is the primary cause of Chronic Obstructive Pulmonary Disease (COPD), and an important pathophysiologic event in COPD is CS-induced apoptosis in lung endothelial cells (EC). Cortactin (CTTN) is a cytoskeletal actin-binding regulatory protein with modulation by Src-mediated tyrosine phosphorylation. Based upon data demonstrating reduced CTTN mRNA levels in the lungs of smokers compared to non-smokers, we hypothesized a functional role for CTTN in CS-induced mitochondrial ROS generation and apoptosis in lung EC. Exposure of cultured human lung EC to CS condensate (CSC) led to the rearrangement of the actin cytoskeleton and increased CTTN tyrosine phosphorylation (within hours). Exposure to CS significantly increased EC mitochondrial ROS generation and EC apoptosis. The functional role of CTTN in these CSC-induced EC responses was explored using cortactin siRNA to reduce its expression, and by using a blocking peptide for the CTTN SH3 domain, which is critical to cytoskeletal interactions. CTTN siRNA or blockade of its SH3 domain resulted in significantly increased EC mitochondrial ROS and apoptosis and augmented CSC-induced effects. Exposure of lung EC to e-cigarette condensate demonstrated similar results, with CTTN siRNA or SH3 domain blocking peptide increasing lung EC apoptosis. These data demonstrate a novel role for CTTN in modulating lung EC apoptosis induced by CS or e-cigarettes potentially providing new insights into COPD pathogenesis.

Heme Oxygenase-1 at the Nexus of Endothelial Cell Fate Decision Under Oxidative Stress

Endothelial cells (ECs) form the inner lining of blood vessels and are central to sensing chemical perturbations that can lead to oxidative stress. The degree of stress is correlated with divergent phenotypes such as quiescence, cell death, or senescence. Each possible cell fate is relevant for a different aspect of endothelial function, and hence, the regulation of cell fate decisions is critically important in maintaining vascular health. This study examined the oxidative stress response (OSR) in human ECs at the boundary of cell survival and death through longitudinal measurements, including cellular, gene expression, and perturbation measurements. 0.5 mM hydrogen peroxide (HP) produced significant oxidative stress, placed the cell at this junction, and provided a model to study the effectors of cell fate. The use of systematic perturbations and high-throughput measurements provide insights into multiple regimes of the stress response. Using a systems approach, we decipher molecular mechanisms across these regimes. Significantly, our study shows that heme oxygenase-1 (HMOX1) acts as a gatekeeper of cell fate decisions. Specifically, HP treatment of HMOX1 knockdown cells reversed the gene expression of about 51% of 2,892 differentially expressed genes when treated with HP alone, affecting a variety of cellular processes, including anti-oxidant response, inflammation, DNA injury and repair, cell cycle and growth, mitochondrial stress, metabolic stress, and autophagy. Further analysis revealed that these switched genes were highly enriched in three spatial locations viz., cell surface, mitochondria, and nucleus. In particular, it revealed the novel roles of HMOX1 on cell surface receptors EGFR and IGFR, mitochondrial ETCs (MTND3, MTATP6), and epigenetic regulation through chromatin modifiers (KDM6A, RBBP5, and PPM1D) and long non-coding RNA (lncRNAs) in orchestrating the cell fate at the boundary of cell survival and death. These novel aspects suggest that HMOX1 can influence transcriptional and epigenetic modulations to orchestrate OSR affecting cell fate decisions.

Modulation of cigarette smoke extract-induced human bronchial epithelial damage by eucalyptol and curcumin

Smoking is one of the most important leading death cause worldwide. From a toxicological perspective, cigarette smoke serves hazards especially for the human being exposed to passive smoke. Over the last decades, the effects of natural compounds on smoking-mediated respiratory diseases such as COPD, asthma, and lung cancer have been under investigation, as well as the mechanistic aspects of disease progression. In the present study, the protective mechanism of eucalyptol (EUC), curcumin (CUR), and their combination on BEAS-2B cells were investigated in vitro to understand their impact on cell death, oxidative cell injury, and inflammatory response induced by 3R4F reference cigarette extract (CSE). According to the present findings, EUC, CUR, and their combination improved cell viability, attenuated CSE-induced apoptosis, and LC3B expression. Further, CSE-induced oxidative damage and inflammatory response in human bronchial epithelial cells were remarkably reduced by the combination treatment through modification of enzymatic antioxidant activity, GSH, MDA, and intracellular ROS levels as well as nitrite and IL-6 levels. In addition, nuclear translocation of Nrf2, a regulatory protein involved in the indirect antioxidant response, was remarkably up-regulated with the combination pre-treatment. In conclusion, EUC and CUR in combination might be a potential therapeutic against smoking-induced lung diseases through antioxidant and inflammatory pathways and results represent valuable background for future in vivo pulmonary toxicity studies.

Time-resolved proteomic profiling of cigarette smoke-induced experimental chronic obstructive pulmonary disease

BACKGROUND AND OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is the third leading cause of illness and death worldwide. Current treatments aim to control symptoms with none able to reverse disease or stop its progression. We explored the major molecular changes in COPD pathogenesis.

METHODS

We employed quantitative label-based proteomics to map the changes in the lung tissue proteome of cigarette smoke-induced experimental COPD that is induced over 8 weeks and progresses over 12 weeks.

RESULTS

Quantification of 7324 proteins enabled the tracking of changes to the proteome. Alterations in protein expression profiles occurred in the induction phase, with 18 and 16 protein changes at 4- and 6-week time points, compared to age-matched controls, respectively. Strikingly, 269 proteins had altered expression after 8 weeks when the hallmark pathological features of human COPD emerge, but this dropped to 27 changes at 12 weeks with disease progression. Differentially expressed proteins were validated using other mouse and human COPD bronchial biopsy samples. Major changes in RNA biosynthesis (heterogeneous nuclear ribonucleoproteins C1/C2 [HNRNPC] and RNA-binding protein Musashi homologue 2 [MSI2]) and modulators of inflammatory responses (S100A1) were notable. Mitochondrial dysfunction and changes in oxidative stress proteins also occurred.

CONCLUSION

We provide a detailed proteomic profile, identifying proteins associated with the pathogenesis and disease progression of COPD establishing a platform to develop effective new treatment strategies.

Cigarette smoke-induced toxicity consequences of intracellular iron dysregulation and ferroptosis

Despite numerous studies on the mechanisms of cigarette smoking toxicity over the past three decades, some aspects remain obscure. Recent developments have drawn attention to some hopeful indicators that allow us to advance our awareness of cigarette-induced cell death. Ferroptosis is considered a type of governed death of cells distinguished by the iron-dependent lipid hydroperoxide deposition to fatal concentrations. Ferroptosis has been linked with pathological settings such as neurodegenerative diseases, cancer, heart attack, hemorrhagic stroke, traumatic brain injury, ischemia-reperfusion injury, and renal dysfunction. This review tries to explain the causal role of ferroptosis cascade in cigarette smoke-mediated toxicity and cell death, highlighting associations on potential action mechanisms and proposing suggestions for its detoxifying and therapeutic interventions.

The Restorative Effect of Red Guava (Psidium guajava L.) Fruit Extract on Pulmonary Tissue of Rats (Rattus norvegicus) Exposed to Cigarette Smoke

Since the damage to alveolar tissue due to cigarette smoke exposure (CSE) is lipid peroxidation, antioxidant treatment is needed. The red guava (Psidium guajava L.) fruit contains antioxidants derived from quercetin, lycopene, and vitamin C. This study aimed to determine the effect of red guava fruit extract (RGFE) on the alveolar tissue of rats exposed to cigarette smoke. The 25 rats (Rattus norvegicus) were divided into five groups. The control and T0 groups were only administered placebo, while T1, T2, and T3 groups were orally administered RGFE of 18.9, 37.8, and 56.7 mg/kg body weight daily for 44 days. The CSE dose of 20 suctions daily was conducted on T0, T1, T2, and T3 groups on days 15–44. On day 45, all rats were sacrificed for serum collection and histopathological lung slides with eosin-nigrosin staining. The result showed that CSE caused an increase (p < 0.05) in malondialdehyde (MDA) levels, cell death, apoptosis, and necrosis percentages, congestion and thickening of alveolar septum tissue, and reduction in the alveolar diameter and alveolar number. Administration of RGFE suppressed those effects, and the highest dose of RGFE (T3) restored (p > 0.05) MDA levels, percentage of apoptotic and necrosis, alveolar septal thickening, and alveolar diameter. However, the percentages of cell death, alveolar congestion, and the alveolar number were still worse (p < 0.05) than in normal rats. It could be concluded that RGFE has proved relief and restoration of the alveolar tissue of rats exposed to cigarette smoke.

The in vitro ToxTracker and Aneugen Clastogen Evaluation extension assay as a tool in the assessment of relative genotoxic potential of e-liquids and their aerosols

In vitro (geno)toxicity assessment of electronic vapour products (EVPs), relative to conventional cigarette, currently uses assays, including the micronucleus and Ames tests. Whilst informative on induction of a finite endpoint and relative risk posed by test articles, such assays could benefit from mechanistic supplementation. The ToxTracker and Aneugen Clastogen Evaluation analysis can indicate the activation of reporters associated with (geno)toxicity, including DNA damage, oxidative stress, the p53-related stress response and protein damage. Here, we tested for the different effects of a selection of neat e-liquids, EVP aerosols and Kentucky reference 1R6F cigarette smoke samples in the ToxTracker assay. The assay was initially validated to assess whether a mixture of e-liquid base components, propylene glycol (PG) and vegetable glycerine (VG) had interfering effects within the system. This was achieved by spiking three positive controls into the system with neat PG/VG or phosphate-buffered saline bubbled (bPBS) PG/VG aerosol (nicotine and flavour free). PG/VG did not greatly affect responses induced by the compounds. Next, when compared to cigarette smoke samples, neat e-liquids and bPBS aerosols (tobacco flavour; 1.6% freebase nicotine, 1.6% nicotine salt or 0% nicotine) exhibited reduced and less complex responses. Tested up to a 10% concentration, EVP aerosol bPBS did not induce any ToxTracker reporters. Neat e-liquids, tested up to 1%, induced oxidative stress reporters, thought to be due to their effects on osmolarity in vitro. E-liquid nicotine content did not affect responses induced. Additionally, spiking nicotine alone only induced an oxidative stress response at a supraphysiological level. In conclusion, the ToxTracker assay is a quick, informative screen for genotoxic potential and mechanisms of a variety of (compositionally complex) samples, derived from cigarettes and EVPs. This assay has the potential for future application in the assessment battery for next-generation (smoking alternative) products, including EVPs.

Short-term whole body cigarette smoke exposure induces regional differences in cellular response in the mouse larynx

The larynx is an essential organ in the respiratory tract and necessary for airway protection, respiration, and phonation. Cigarette smoking is a significant risk factor associated with benign and malignant laryngeal diseases. Despite this association, the underlying mechanisms by which cigarette smoke (CS) drives disease development are not well elucidated. In the current study, we developed a short-term murine whole body inhalation model to evaluate the first CS-induced cellular responses in the glottic [i.e. vocal fold (VF)] and subglottic regions of the larynx. Specifically, we investigated epithelial cell proliferation, cell death, surface topography, and mucus production, at various time points (1 day, 5 days, 10 days) after ∼ 2 h exposure to 3R4F cigarettes (Delivered dose: 5.6968 mg/kg per cigarette) and following cessation for 5 days after a 5 day CS exposure (CSE). CSE elevated levels of BrdU labeled proliferative cells and p63 labeled epithelial basal cells on day 1 in the VF. CSE increased proliferative cells in the subglottis at days 5, 10 and following cessation in the subglottis. Cleaved caspase-3 apoptotic activity was absent in VF at all time points and increased at day 1 in the subglottis. Evaluation of the VF surface by scanning electron microscopy (SEM) revealed significant epithelial microprojection damage at day 10 and early signs of necrosis at days 5 and 10 post-CSE. SEM visualizations additionally indicated the presence of deformed cilia at days 5 and 10 after CSE and post-cessation in the respiratory epithelium lined subglottis. In terms of mucin content, the impact of short-term CSE was observed only at day 10, with decreasing acidic mucin levels and increasing neutral mucin levels. Overall, these findings reveal regional differences in murine laryngeal cellular responses following short-term CSE and provide insight into potential mechanisms underlying CS-induced laryngeal disease development.

Suppression of apoptosis in vascular endothelial cell, the promising way for natural medicines to treat atherosclerosis

Atherosclerosis, a chronic multifactorial disease, is closely related to the development of cardiovascular diseases and is one of the predominant causes of death worldwide. Normal vascular endothelial cells play an important role in maintaining vascular homeostasis and inhibiting atherosclerosis by regulating vascular tension, preventing thrombosis and regulating inflammation. Currently, accumulating evidence has revealed that endothelial cell apoptosis is the first step of atherosclerosis. Excess apoptosis of endothelial cells induced by risk factors for atherosclerosis is a preliminary event in atherosclerosis development and might be a target for preventing and treating atherosclerosis. Interestingly, accumulating evidence shows that natural medicines have great potential to treat atherosclerosis by inhibiting endothelial cell apoptosis. Therefore, this paper reviewed current studies on the inhibitory effect of natural medicines on endothelial cell apoptosis and summarized the risk factors that may induce endothelial cell apoptosis, including oxidized low-density lipoprotein (ox-LDL), reactive oxygen species (ROS), angiotensin II (Ang II), tumor necrosis factor-α (TNF-α), homocysteine (Hcy) and lipopolysaccharide (LPS). We expect this review to highlight the importance of natural medicines, including extracts and monomers, in the treatment of atherosclerosis by inhibiting endothelial cell apoptosis and provide a foundation for the development of potential antiatherosclerotic drugs from natural medicines.

Smoking associates with distinct clinical phenotypes in patients with systemic lupus erythematosus: a nationwide Danish cross-sectional study

Objectives

SLE displays large clinical heterogeneity that beyond genetic factors may be determined by environmental exposures. In this Danish nationwide study, we aimed to determine if clinical subsets of SLE were associated with smoking history.

Methods

At each of six participating centres, incident or prevalent inpatients and outpatients with SLE were consecutively included. Manifestations forming the basis of SLE classification were registered in an electronic chart system. Patients also provided questionnaire-based data on environmental exposures, including smoking history. Hierarchical cluster analysis was conducted to determine and characterise subsets of patients with similar traits of disease manifestations. Levels of smoking exposure by pack-years were correlated to the identified SLE subsets, as well as discrete SLE manifestations.

Results

The cohort consisted of 485 patients (88% women and 92% Caucasian) with SLE of which 51% were ever smokers. Common disease manifestations comprised non-erosive arthritis (81%), malar rash (57%), lymphopenia (55%), photosensitivity (50%) and persistent proteinuria (41%). We identified three distinct phenotypic clusters characterised by their preponderance of (A) neurological, serosal and mucosal involvement; (B) renal, haematological and immunological disorders; and (C) acute and chronic skin manifestations. Cluster B was the youngest and had the lowest level of smoking exposure. Age-adjusted regression analyses showed that compared with never smokers a smoking history of >20 pack-years was associated with neurological disorder (OR=3.16), discoid rash (OR=2.22), photosensitivity (OR=2.19) and inversely with haematological disorder (OR=0.40), renal disorder (OR=0.40) and non-erosive arthritis (OR=0.45), p<0.05 for all.

Conclusions

Our findings support that SLE presents in varying clinical phenotypes and suggest that they may have differentiated associations with smoking history.

Impact of cigarette versus electronic cigarette aerosol conditioned media on aortic endothelial cells in a microfluidic cardiovascular model

Atherosclerosis is a complex process involving progressive pathological events, including monocyte adhesion to the luminal endothelial surface. We have developed a functional in vitro adhesion assay using BioFlux microfluidic technology to investigate THP-1 (human acute monocytic leukaemia cell) monocyte adhesion to human aortic endothelial cells (HAECs). The effect of whole smoke conditioned media (WSCM) generated from University of Kentucky reference cigarette 3R4F, electronic cigarette vapour conditioned media (eVCM) from an electronic nicotine delivery system (ENDS) product (Vype ePen) and nicotine on monocyte adhesion to HAECs was evaluated. Endothelial monolayers were grown in microfluidic channels and exposed to 0–1500 ng/mL nicotine or nicotine equivalence of WSCM or eVCM for 24 h. Activated THP-1 cells were perfused through the channels and a perfusion, adhesion period and wash cycle performed four times with increasing adhesion period lengths (10, 20, 30 and 40 min). THP-1 cell adhesion was quantified by counting adherent cells. WSCM induced dose-dependent increases in monocyte adhesion compared to vehicle control. No such increases were observed for eVCM or nicotine. Adhesion regulation was linked to increased ICAM-1 protein expression. Staining of ICAM-1 in HAECs and CD11b (MAC-1) in THP-1 cells demonstrated adhesion molecule co-localisation in BioFlux plates. The ICAM-1 adhesion response to WSCM was downregulated by transfecting HAECs with ICAM-1 siRNA. We conclude that the BioFlux system is able to model human monocyte adhesion to primary human endothelial cells in vitro and WSCM drives the greatest increase in monocyte adhesion via a mechanism involving endothelial ICAM-1 expression.

Effects of cigarette smoke on the administration of isoniazid and rifampicin to macrophages infected with Mycobacterium tuberculosis

BACKGROUND

Smoking is a cause behind many diseases, including tuberculosis, and it is a risk factor for tuberculosis infection and mortality. Moreover, smoking is associated with a poor tuberculosis treatment outcome.

OBJECTIVES

In this study, we focus on the effects of cigarette smoke on an infected cell culture treated with anti-tuberculosis drugs.

MATERIALS AND METHODS

Cytotoxicity on THP-1, J774A.1 and MH-S cell lines and growth of Mycobacterium tuberculosis exposed to a reference or a commercial cigarette was evaluated. THP-1 cell line was exposed to cigarette smoke, infected with Mycobacterium tuberculosis and treated with anti-tuberculosis drugs. Apoptosis and death cell were also tested on M. bovis BCG infected cells. Minimal inhibitory concentrations of anti-tuberculosis drugs were analyzed.

RESULTS

All cells lines showed viability values higher than 80% when exposed to cigarette smoke extract. However, THP-1 cell line infected with M. bovis BCG and exposed to Marlboro cigarette smoke showed up to a 54% reduction of apoptotic cells than cells unexposed to smoke. M. tuberculosis exposed to Marlboro cigarette smoke for 11 days had an optical density 16% lower than unexposed bacteria. When cells were infected with M. tuberculosis, the intracellular recovery of CFUs showed up to a 0.66 log reduction in cells exposed to cigarette smoke extract because of a potential impairment in the phagocytosis. Macrophages treated with drugs showed up to a 2.55 log reduction in the intracellular load burden compared with non-treated ones. Despite poor treatment outcome on TB smoker patients, minimal inhibitory concentration of rifampicin increased only 2-fold in M. tuberculosis exposed to cigarette smoke.

CONCLUSION

Smoking interferes with tuberculosis treatment impairing the immunity of the host.

Cigarette smoke extract induces airway epithelial cell death via repressing PRMT6/AKT signaling

Chronic obstructive pulmonary disease (COPD) is a severe public health threat world-wide. Cigarette smoke (CS)-induced airway epithelial cell death is a major pathway of pathogenesis in emphysema, a subtype of COPD. Protein arginine methyltransferase 6 (PRMT6) is a type I PRMT that catalyzes mono- and di-methylation on arginine residues within histone and non-histone proteins to modulate a variety of life processes, such as apoptosis. However, its role in CS-induced lung epithelial death has not been fully elucidated. Here we report that PRMT6 was decreased in mouse lung tissues from a cigarette smoke extract (CSE)-mediated experimental emphysematous model and in CSE treated or cigarette smoke exposed lung epithelial cells. Depletion of PRMT6 increased the protein levels of phosphatase PTEN and PI3K regulatory subunit p85 but decreased a downstream kinase PDK1, resulting in AKT dephosphorylation and thereafter, lung epithelial cell death. Knockout of PRMT6 inhibited epithelial survival and promoted CSE-mediated epithelial cell death, while ectopic expression of PRMT6 protein partially reversed epithelial cell death via PI3K/AKT-mediated cell survival signaling in CSE cellular models. These findings demonstrate that PRMT6 plays a crucial role in CS-induced bronchial epithelial cell death that may be a potential therapeutic target against the airway cell death in CS-induced COPD.

The Protective Role of Bioactive Quinones in Stress-induced Senescence Phenotype of Endothelial Cells Exposed to Cigarette Smoke Extract

Endothelial dysfunction represents the initial stage in atherosclerotic lesion development which occurs physiologically during aging, but external factors like diet, sedentary lifestyle, smoking accelerate it. Since cigarette smoking promotes oxidative stress and cell damage, we developed an in vitro model of endothelial dysfunction using vascular cells exposed to chemicals present in cigarette smoke, to help elucidate the protective effects of anti-inflammatory and antioxidant agents, such as ubiquinol and vitamin K, that play a fundamental role in vascular health. Treatment of both young and senescent Human Umbilical Vein Endothelial Cells (HUVECs) for 24 h with cigarette smoke extract (CSE) decreased cellular viability, induced apoptosis via reactive oxygen species (ROS) imbalance and mitochondrial dysfunction and promoted an inflammatory response. Moreover, the senescence marker SA-β-galactosidase was observed in both young CSE-exposed and in senescent HUVECs suggesting that CSE exposure accelerates aging in endothelial cells. Supplementation with 10 µM ubiquinol and menaquinone-7 (MK7) counteracted oxidative stress and inflammation, resulting in improved viability, decreased apoptosis and reduced SA-β-galactosidase, but were ineffective against CSE-induced mitochondrial permeability transition pore opening. Other K vitamins tested like menaquinone-4 (MK4) and menaquinone-1 (K1) were less protective. In conclusion, CSE exposure was able to promote a stress-induced senescent phenotype in young endothelial cells likely contributing to endothelial dysfunction in vivo. Furthermore, the molecular changes encountered could be offset by ubiquinol and menaquinone-7 supplementation, the latter resulting the most bioactive K vitamin in counteracting CSE-induced damage.

Dual stimuli-responsive release of aptamer AS1411 decorated erlotinib loaded chitosan nanoparticles for non-small-cell lung carcinoma therapy

The present work was developed the pH dependent-aptamer AS1411 (APT) decorated and erlotinib (En) loaded chitosan nanoparticles (CSNPs) for promising non-small-cell lung carcinoma (NSCLC) treatment. The characterization studies revealed that formulated APT-En-CSNPs were spherical in shape with size of 165.95 d. nm and PDI of 0.212. FTIR spectrum recorded molecular chemical interactions with composition of En or En-CSNPs. Cell viability assay, flow cytometry and fluorescent microscopy results revealed that APT-En-CSNPs triggered cancer cell death through pH-sensitive and nucleolin receptor-targeted release of En. The decoration of the APT improved the cellular uptake of En as evidenced by cellular sensing fluorescence and BioTEM assay. The APT-En-CSNPs induced the apoptosis through excessive ROS generation, nucleus damage and Δψm loss in the A549 cells. Hence, the present study revealed that the APT-En-CSNPs improved the therapeutic efficiency of En in NSCLC through the nucleolin targeted drug release.

TIPE1 accelerates atherogenesis by inducing endothelial dysfunction in response to oxidative stress

Atherosclerosis is an inflammatory disease of the arterial wall, which involves endothelial cells and immune cells. Endothelial dysfunction has been considered an important step in the initiation of the disease. TIPE1 is a newly identified protein of the TIPE family, and plays a vital role in inflammation and tumorigenesis. However, its role in atherogenesis remains unclear. In this study, we demonstrated that TIPE1 promoted atherogenesis by inducing endothelial dysfunction. When human umbilical vein endothelial cells (HUVECs) were exposed to oxidative stress, the level of TIPE1 was significantly up-regulated, and the ROS generation markedly increased in TIPE1 over-expressing HUVECs. As a result, the growth of HUVECs was inhibited, and the apoptosis was enhanced. However, the cell contact ability between HUVECs and THP-1 cells were augmented due to the up-regulation of adhesion molecules such as E-selectin and ICAM-1 induced by TIPE1 overexpression. Importantly, ApoE^-/- mice injected with TIPE1 recombinant lentivirus developed significantly severe atherosclerosis accompanied by hyperglycemia, hypercholesterolemia and increased white blood count. These findings indicated that excessive ROS induced by the overexpression of TIPE1 in endothelial cells accelerated the process of atherogenesis.

Biophysical and biomechanical properties of neural progenitor cells as indicators of developmental neurotoxicity

Conventional in vitro toxicity studies have focused on identifying IC₅₀ and the underlying mechanisms, but how toxicants influence biophysical and biomechanical changes in human cells, especially during developmental stages, remain understudied. Here, using an atomic force microscope, we characterized changes in biophysical (cell area, actin organization) and biomechanical (Young's modulus, force of adhesion, tether force, membrane tension, tether radius) aspects of human fetal brain-derived neural progenitor cells (NPCs) induced by four classes of widely used toxic compounds, including rotenone, digoxin, N-arachidonoylethanolamide (AEA), and chlorpyrifos, under exposure up to 36 h. The sub-cellular mechanisms (apoptosis, mitochondria membrane potential, DNA damage, glutathione levels) by which these toxicants induced biochemical changes in NPCs were assessed. Results suggest a significant compromise in cell viability with increasing toxicant concentration (p < 0.01), and biophysical and biomechanical characteristics with increasing exposure time (p < 0.01) as well as toxicant concentration (p < 0.01). Impairment of mitochondrial membrane potential appears to be the most sensitive mechanism of neurotoxicity for rotenone, AEA and chlorpyrifos exposure, but compromise in plasma membrane integrity for digoxin exposure. The surviving NPCs remarkably retained stemness (SOX2 expression) even at high toxicant concentrations. A negative linear correlation (R² = 0.92) exists between the elastic modulus of surviving cells and the number of living cells in that environment. We propose that even subtle compromise in cell mechanics could serve as a crucial marker of developmental neurotoxicity (mechanotoxicology) and therefore should be included as part of toxicology assessment repertoire to characterize as well as predict developmental outcomes.

Enhanced cancer therapy with pH-dependent and aptamer functionalized doxorubicin loaded polymeric (poly D, L-lactic-co-glycolic acid) nanoparticles

Aptamer based drug delivery systems are gaining the importance in anticancer therapy due to their targeted drug delivery efficiency without harming the normal cells. The present work formulated the pH-dependent aptamer functionalized polymer-based drug delivery system against human lung cancer. The prepared aptamer functionalized doxorubicin (DOX) loaded poly (D, L-lactic-co-glycolic acid) (PLGA), poly (N-vinylpyrrolidone) (PVP) nanoparticles (APT-DOX-PLGA-PVP NPs) were spherical in shape with an average size of 87.168 nm. The crystallography and presence of the PLGA (poly (D, L-lactic-co-glycolic acid)) and DOX (doxorubicin) in APT-DOX-PLGA-PVP NPs were indicated by the X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), and ¹H and ¹³C nuclear magnetic resonance spectrometer (NMR). The pH-dependent aptamer AS1411 based drug release triggered the cancer cell death was evidenced by cytotoxicity assay, flow cytometry, and fluorescent microscopic imaging. In addition, the cellular uptake of the DOX was determined and the apoptosis-related signaling pathway in the A549 cells was studied by Western blot analysis. Further, the in vivo study revealed that mice treated with APT-DOX-PLGA-PVP NPs were significantly recovered from cancer as evident by mice weight and tumor size followed by the histopathological study. It was reported that the APT-DOX-PLGA-PVP NPs induced the apoptosis through the activation of the apoptosis-related proteins. Hence, the present study revealed that the APT-DOX-PLGA-PVP NPs improved the therapeutic efficiency through the nucleolin receptor endocytosis targeted drug release.

The effects of cigarette smoking extracts on cell cycle and tumor spread: novel evidence

Cigarette smoking is a major preventable risk factor for lung cancer, contributing to lung cancer progression and metastasis. Moreover, cigarette smoking correlates with increased metastasis frequency of pancreatic, breast and bladder cancer. The aim of this review was to examine the role of cigarette smoke extract in cell cycle and cancer progression. Clinical impact and the effects of cigarette smoke extract on carcinogenesis are discussed. 98 of the over 5000 chemicals in tobacco smoke are known carcinogens that can act on cancer genes such as K-RAS and p53. Through various mechanisms these compounds can activate molecules involved in the cell cycle, such as cyclins, and molecules involved in apoptosis and autophagy, such as Beclin-1 or LC3B. A search of the literature, including in vitro and in vivo studies, was carried out and the results summarized.

There is evidence of cancerogenic effects of cigarette smoke compounds. Cigarette smoke extract is a tobacco condensate obtained by filtration processes. Studies have shown that it can modify the cell cycle, inducing uncontrolled cell proliferation. This effect occurs through activation of genetic and epigenetic pathways and increasing the expression of proteins involved in inflammation. The pathways activated by cigarette smoke extract open up opportunities for researchers to develop new targeted therapies toward the specific molecules involved. Furthermore, the effects exerted by cigarette smoke extract on normal epithelial cells hold potential for use in the development of prevention medicine and early cancer diagnosis.

Alternative Oxidase Attenuates Cigarette Smoke-induced Lung Dysfunction and Tissue Damage

Cigarette smoke (CS) exposure is the predominant risk factor for the development of chronic obstructive pulmonary disease (COPD) and the third leading cause of death worldwide. We aimed to elucidate whether mitochondrial respiratory inhibition and oxidative stress are triggers in its etiology. In different models of CS exposure, we investigated the effect on lung remodeling and cell signaling of restoring mitochondrial respiratory electron flow using alternative oxidase (AOX), which bypasses the cytochrome segment of the respiratory chain. AOX attenuated CS-induced lung tissue destruction and loss of function in mice exposed chronically to CS for 9 months. It preserved the cell viability of isolated mouse embryonic fibroblasts treated with CS condensate, limited the induction of apoptosis, and decreased the production of reactive oxygen species (ROS). In contrast, the early-phase inflammatory response induced by acute CS exposure of mouse lung, i.e., infiltration by macrophages and neutrophils and adverse signaling, was unaffected. The use of AOX allowed us to obtain novel pathomechanistic insights into CS-induced cell damage, mitochondrial ROS production, and lung remodeling. Our findings implicate mitochondrial respiratory inhibition as a key pathogenic mechanism of CS toxicity in the lung. We propose AOX as a novel tool to study CS-related lung remodeling and potentially to counteract CS-induced ROS production and cell damage.

Excessive miR-25-3p maturation via N6-methyladenosine stimulated by cigarette smoke promotes pancreatic cancer progression

N6-methyladenosine (m6A) modification is an important mechanism in miRNA processing and maturation, but the role of its aberrant regulation in human diseases remained unclear. Here, we demonstrate that oncogenic primary microRNA-25 (miR-25) in pancreatic duct epithelial cells can be excessively maturated by cigarette smoke condensate (CSC) via enhanced m6A modification that is mediated by NF-κB associated protein (NKAP). This modification is catalyzed by overexpressed methyltransferase-like 3 (METTL3) due to hypomethylation of the METTL3 promoter also caused by CSC. Mature miR-25, miR-25-3p, suppresses PH domain leucine-rich repeat protein phosphatase 2 (PHLPP2), resulting in the activation of oncogenic AKT-p70S6K signaling, which provokes malignant phenotypes of pancreatic cancer cells. High levels of miR-25-3p are detected in smokers and in pancreatic cancers tissues that are correlated with poor prognosis of pancreatic cancer patients. These results collectively indicate that cigarette smoke-induced miR-25-3p excessive maturation via m6A modification promotes the development and progression of pancreatic cancer.

Hypermethylation of mitochondrial transcription factor A induced by cigarette smoke is associated with chronic obstructive pulmonary disease

Purpose of the study: Cigarette smoking is a leading environmental contributor to chronic obstructive pulmonary disease (COPD), but its epigenetic regulation of mtTFA gene remains elusive. This study aims to explore the relationship of DNA methylation of mtTFA and cigarette smoking in COPD. Materials and Methods: We analyzed DNA methylation on mtTFA promoters in clinical samples from COPD patients and subjects with normal pulmonary function. Expression of mtTFA mRNA in the clinical samples and mtTFA mRNA and protein in human umbilical vein endothelial cells(HUVECs) treated with cigarette smoke extract (CSE) was evaluated. mtTFA mRNA and protein levels were measured to determine effects of demethylation agents on CSE-treated HUVECs. Results: The DNA methylation level of the mtTFA promoter was significantly increased in COPD group. Expression of mtTFA mRNA was downregulated in the lungs as a consequence of hypermethylation of mtTFA promoter. Expression of mtTFA mRNA and protein was downregulated in CSE-treated HUVECs as a consequence of hypermethylation of the mtTFA promoter. mtTFA expression in CSE-treated HUVECs was restored by the methylation inhibitor, 5-aza-2'-deoxycytidine(AZA). Conclusions: Cigarette smoke-induced hypermethylation of the mtTFA promoter is related to the initiation and progression of COPD. Our finding may provide a new strategy for the intervention of COPD by developing demethylation agents targeting mtTFA hypermethylation.

Mechanisms of whole smoke conditioned media induced cytotoxicity to human aortic endothelial cells

Chronic exposure to cigarette smoke can lead to endothelial dysfunction and potentially endothelial cell death. Here, we exposed Human Aortic Endothelial Cells (HAECs) to whole smoke conditioned media (WSCM) over a range of nicotine equivalence (n.e.) concentrations (0-8000 ng/mL n.e.). After 24 h, Neutral Red Uptake (NRU) and reduction of 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) to formazan was determined for each exposure concentration and compared to control. IC₅₀ values in the NRU assay were: 4582 ng/mL n.e. ± 1074, 4587 ng/mL n.e. ± 951, 4993 ng/mL n.e. ± 1239 and 4691 ng/mL n.e. ± 402 for four HAEC donors. IC₅₀ values in the MTT assay were: 4885 ng/mL n.e. ± 1341, 4584 ng/mL n.e. ± 806, 5749 ng/mL n.e. ± 783 and 5228 ng/mL n.e. ± 593 for the four donors. To examine the mechanism responsible for WSCM-induced cytotoxicity in HAECs, flow cytometry using necrosis (Propidium Iodide) and apoptosis (Annexin V) markers were used. Annexin V-positive cell populations increased in a dose dependent manner while increases in PI-positive cell populations occurred at the highest doses of WSCM (5000-8000 ng/mL n.e.). Western blotting for cleaved caspase-3 confirmed that apoptosis occurs at >5000 ng/mL n.e. WSCM, coinciding with reduced HAEC survival.

Early inhibition of endothelial retinoid uptake upon myocardial infarction restores cardiac function and prevents cell, tissue, and animal death

Physiologically, following myocardial infarction (MI), retinoid levels elevate locally in the infarcted area. Whereas therapeutic systemic application of retinoids was shown to reduce the progression of ventricular dilatation and the onset of heart failure, the role of acute physiologically increased retinoids in the infarction zone is unknown to date. To reveal the role of local retinoids in the MI zone is the central aim of this study. Using human cell culture and co-culture models for hypoxia as well as various assays systems, lentivirus-based transgene expression, in silico molecular docking studies, and an MI model in rats, we analysed the impact of the retinoid all-trans retinoic acid (ATRA) on cell signalling, cell viability, tissue survival, heart function, and MI-induced death in rats. Based on our results, ATRA-mediated signalling does aggravate the MI phenotype (e.g. 2.5-fold increased mortality compared to control), whereas 5'-methoxyleoligin (5ML), a new agent which interferes with ATRA-signalling rescues the ATRA-dependent phenotype. On the molecular level, ATRA signalling causes induction of TXNIP, a potent inhibitor of the physiological antioxidant thioredoxin (TRX1) and sensitizes cells to necrotic cell death upon hypoxia. 5ML-mediated prevention of ATRA effects were shown to be based on the inhibition of cellular ATRA uptake by interference with the cholesterol (and retinol) binding motif of the transmembrane protein STRA6. 5ML-mediated inhibition of ATRA uptake led to a strong reduction of ATRA-dependent gene expression, reduced ROS formation, and protection from necrotic cell death. As 5ML exerted a cardioprotective effect, also independent of its inhibition of cellular ATRA uptake, the agent likely has another cardioprotective property, which may rely on the induction of TRX1 activity. In summary, this is the first study to show i) that local retinoids in the early MI zone may worsen disease outcome, ii) that inhibition of endothelial retinoid uptake using 5ML may constitute a novel treatment strategy, and iii) that targeting endothelial and myocardial retinoid uptake (e.g. via STRA6 inhibition) may constitute a novel treatment target in acute MI.

In vitro systems toxicology-based assessment of the potential modified risk tobacco product CHTP 1.2 for vascular inflammation- and cytotoxicity-associated mechanisms promoting adhesion of monocytic cells to human coronary arterial endothelial cells

Cigarette smoking causes cardiovascular diseases. Heating tobacco instead of burning it reduces the amount of toxic compounds in the aerosol and may exert a reduced impact on health compared with cigarette smoke. Aqueous extract from the aerosol of a potential modified risk tobacco product, the Carbon Heated Tobacco Product (CHTP) 1.2, was compared in vitro with aqueous extract from the smoke of a 3R4F reference cigarette for its impact on the adhesion of monocytic cells to artery endothelial cells. Human coronary artery endothelial cells (HCAEC) were treated for 4 h with conditioned media from human monocytic Mono Mac 6 (MM6) cells exposed to CHTP1.2 or 3R4F extracts for 2 h or directly with those extracts freshly generated. In vitro monocyte-endothelial cell adhesion was measured concomitantly with inflammatory, oxidative stress, cytotoxicity, and death markers. Furthermore, transcriptomics analyses enabled to quantify the level of perturbation in HCAECs, and provide biological interpretation for the underlying molecular changes following exposure to 3R4F or CHTP1.2 extract. Our systems toxicology study demonstrated that approximately 10-15-fold higher concentrations of the CHTP 1.2 aerosol extract were needed to elicit similar effects as the 3R4F smoke extract on cardiovascular disease-relevant inflammation and cytotoxicity-related mechanisms and markers investigated in vitro.

A Novel In Vivo Model to Study Impaired Tissue Regeneration Mediated by Cigarette Smoke

Cigarette smoke is associated with several pathologies including chronic respiratory diseases and cancer. In addition, exposure to cigarette smoke is correlated with impaired wound healing, where a significant decrease in the regenerative capacity of smokers is well documented and broadly considered a negative risk factor after trauma or surgery. So far, some in vitro and in vivo models have been described to study how exposure to cigarette smoke diminishes the regenerative potential in different organisms. However, although useful, many of these models are difficult and expensive to implement and do not allow high-throughput screening approaches. In order to establish a reliable and accessible model, we have evaluated the effects of cigarette smoke extract (CSE) on zebrafish development and regeneration. In this work, zebrafish embryos and larvae were exposed to low doses of aqueous CSE showing severe developmental abnormalities in a dose-dependent manner. Furthermore, when adult zebrafish were subjected to caudal fin amputation, we observed a significant decrease in the regenerative capacity of animals exposed to CSE. The effect was exacerbated in male and aged fish compared to female or young organisms. The establishment of a zebrafish model to assess the consequences of cigarette smoke and its effects on animal physiology could provide a new tool to study the underlying mechanisms involved in impaired tissue regeneration, and aid the development of novel approaches to treat complications associated with cigarette smoke toxicity.

Immune-regulating effects of exercise on cigarette smoke-induced inflammation

Long-term cigarette smoking (LTCS) represents an important risk factor for cardiac infarction and stroke and the central risk factor for the development of a bronchial carcinoma, smoking-associated interstitial lung fibrosis, and chronic obstructive pulmonary disease. The pathophysiologic development of these diseases is suggested to be promoted by chronic and progressive inflammation. Cigarette smoking induces repetitive inflammatory insults followed by a chronic and progressive activation of the immune system. In the pulmonary system of cigarette smokers, oxidative stress, cellular damage, and a chronic activation of pattern recognition receptors are described which are followed by the translocation of the NF-kB, the release of pro-inflammatory cytokines, chemokines, matrix metalloproteases, and damage-associated molecular patterns. In parallel, smoke pollutants cross directly through the alveolus-capillary interface and spread through the systemic bloodstream targeting different organs. Consequently, LTCS induces a systemic low-grade inflammation and increased oxidative stress in the vascular system. In blood, these processes promote an increased coagulation and endothelial dysfunction. In muscle tissue, inflammatory processes activate catabolic signaling pathways followed by muscle wasting and sarcopenia. In brain, several characteristics of neuroinflammation were described. Regular exercise training has been shown to be an effective nonpharmacological treatment strategy in smoke-induced pulmonary diseases. It is well established that exercise training exerts immune-regulating effects by activating anti-inflammatory signaling pathways. In this regard, the release of myokines from contracting skeletal muscle, the elevations of cortisol and adrenalin, the reduced expression of Toll-like receptors, and the increased mobilization of immune-regulating leukocyte subtypes might be of vital importance. Exercise training also increases the local and systemic antioxidative capacity and several compensatory mechanisms in tissues such as an increased anabolic signaling in muscle or an increased compliance of the vascular system. Accordingly, regular exercise training seems to protect long-term smokers against some important negative local and systemic consequences of smoking. Data suggest that it seems to be important to start exercise training as early as possible.

Molecules of Damage-Associated Patterns in Bronchoalveolar Lavage Fluid and Serum in Chronic Obstructive Pulmonary Disease

Chronic exposure to detrimental environmental factors may induce immunogenic cell death of structural airway cells in chronic obstructive pulmonary disease (COPD). Damage-associated molecular patterns (DAMPs) is a family of heterogeneous molecules released from injured or dead cells, which activate innate and adaptive immune responses on binding to the pattern recognition receptors on cells. This study seeks to define the content of DAMPs in the bronchoalveolar lavage fluid (BALF) and serum of COPD patients, and the possible association of these molecules with clinical disease features. Thirty COPD in advanced disease stages were enrolled into the study. Pulmonary function tests, arterial blood gas content, 6-minute walk test, and BODE index were assessed. The content of DAMPs was estimated using the commercial sandwich-ELISA kits. We found differential alterations in the content of various DAMP molecules. In the main, BALF DAMPs positively associated with age, forced expiratory volume in one second (FEV1), and residual volume (RV); and inversely with PaO₂, residual volume/total lung capacity (RV/TLC) ratio, and the disease severity staging. In serum, DAMPS positively associated with the intensity of smoking and inversely with age, PaO₂, and TLC. In conclusion, DAMPs are present in both BALF and serum of COPD patients, which points to enhanced both local in the lung environment as well as systemic pro-inflammatory vein in this disease. These molecules appear involved with the lung damage and clinical variables featuring COPD. However, since the involvement of various DAMPs in COPD is variable, the exact role they play is by far unsettled and is open to further exploration.

Lung Diseases

Inflammasomes are large innate cytoplasmic complexes that play a major role in promoting inflammation in the lung in response to a range of environmental and infectious stimuli. Inflammasomes are critical for driving acute innate immune responses that resolve infection and maintain tissue homeostasis. However, dysregulated or excessive inflammasome activation can be detrimental. Here, we discuss the plethora of recent data from clinical studies and small animal disease models that implicate excessive inflammasome responses in the pathogenesis of a number of acute and chronic respiratory inflammatory diseases. Understanding of the role of inflammasomes in lung disease is of great therapeutic interest.

Intracellular Ca2+ is an essential factor for cell damage induced by unsaturated carbonyl compounds

The unsaturated carbonyl compounds are known as the environmental pollutants. Acrolein (ACR) and methyl vinyl ketone (MVK) are representative unsaturated carbonyl compounds. ACR is contained in smoke, automobile exhaust, industrial waste, and several foods. MVK is widely used as the industrial chemical. Although ACR and MVK are highly toxic, the molecular mechanism for their cytotoxicity has been unclear. We have previously reported that ACR and MVK are major cytotoxic compounds in the gas phase of cigarette smoke, and protein kinase C (PKC) inhibitor and NADPH oxidases inhibitor partially rescued cells from ACR- or MVK-induced cell death (Noya et al., Toxicology, 314, 1-10, 2013). PKC translocation, which is hallmark for PKC activation, and cell damage were induced by treatment of cultured cells with ACR or MVK. Intracellular Ca2+ chelator completely suppressed ACR- or MVK-induced PKC translocation to the cell membrane and cell damage, while extracellular Ca2+ chelator had no effects on ACR- and MVK-induced cytotoxicity. These results suggest that intracellular Ca2+ is an essential factor for cell damage caused by both PKC-dependent and PKC-independent pathways, and mobilization of Ca2+ from intracellular Ca2+ stores is induced by ACR or MVK.

The Nucleotide-Binding Oligomerization Domain-Like Receptor Family Pyrin Domain-Containing 3 Inflammasome Regulates Bronchial Epithelial Cell Injury and Proapoptosis after Exposure to Biomass Fuel Smoke

The number of individuals in the population exposed to biomass fuel smoke (BS) is far greater than the number of cigarette smokers. About 20% of cigarette smokers develop chronic obstructive pulmonary disease (COPD) due to smoke-induced irreversible damage and sustained inflammation of the airway epithelium. However, the role of BS in COPD pathogenesis remains to be elucidated. In this study, we investigated the expression of nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing (NLRP) 3 and caspase-1 in the bronchial epithelium from patients with COPD, and further determined the specific role of the NLRP3 inflammasome in bronchial epithelium injury using two in vitro models (BS and cigarette smoke [CS]) in the human bronchial epithelial (HBE) cell line (16HBE). After exposure to BS and CS, the release of damage-associated molecular patterns, the transcriptional and translational up-regulation of NLRP3, and the activation of caspase-1 were observed in cells at different time points. Because IL-1β secretion was dependent on the NLRP3 inflammasome, we assessed CXCL-8 production in response to smoke. Using a transwell migration assay in which 16HBE cells and human alveolar macrophages were cocultured, we showed that smoke-induced NLRP3 activation in 16HBE cells increased the migration of human alveolar macrophages. When the NLRP3 expression was silenced, the average migration distance of 16HBE was increased in scratch assay, because the activation of NLRP3 induced apoptosis by the p53-Bax mitochondrial pathway in the smoke-induced response. These results demonstrate the importance of the NLRP3 inflammasome in mediating BS- and CS-induced HBE cell damage and proapoptosis.

A comparative assessment of e-cigarette aerosols and cigarette smoke on in vitro endothelial cell migration

Cigarette smoking is a risk factor for several diseases. There has been a steep increase in the use of e-cigarettes that may offer a safer alternative to cigarette smoking. In vitro models of smoking-related diseases may provide valuable insights into disease mechanisms associated with tobacco use and could be used to assess e-cigarettes. We previously reported the application of a 'scratch wound' assay, measuring endothelial cell migration rate following artificial wounding, in the presence or absence of cigarette smoke extracts. This study reports the comparative effects of two commercial e-cigarette products (Vype ePen and Vype eStick) and a scientific reference cigarette (3R4F) on endothelial migration in vitro. Puff-matched extracts were generated using the Health Canada Intense (HCI) regime for cigarettes and a modified HCI for e-cigarettes. Exposure to 3R4F extract (20h) induced concentration-dependent inhibition of endothelial cell migration, with complete inhibition at concentrations >20%. E-cigarette extracts did not inhibit migration, even at double the 3R4F extract nicotine concentration, allowing cells to migrate into the wounded area. Our data demonstrate that e-cigarettes do not induce the inhibition of endothelial cell migration in vitro when compared to 3R4F. The scratch wound assay enables the comparative assessment between tobacco and nicotine products in vitro.

Honokiol protects skin cells against inflammation, collagenolysis, apoptosis, and senescence caused by cigarette smoke damage

BACKGROUND

Pollution, especially cigarette smoke, is a major cause of skin damage.

OBJECTIVES

To assess the effects of the small molecule polyphenol, honokiol, on reversing cigarette smoke-induced damage in vitro to relevant skin cells.

METHODS

Keratinocytes (HaCat) cultures were exposed to cigarette smoke and, after 48 hours, IL-1α and IL-8 were measured in cell supernatants. Moreover, TIMP-2 production, apoptosis rate, and senescence β-galactosidase expression were evaluated in primary human foreskin fibroblasts (HFF-1) cultures.

RESULTS

Honokiol at 10 μm reduced IL-1α production by 3.4 folds (P < 0.05) and at 10 and 20 μm reduced IL-8 by 23.9% and 53.1% (P < 0.001), respectively, in HaCat keratinocytes. In HFF-1, honokiol restored TIMP-2 production by 96.9% and 91.9% (P < 0.001), respectively, at 10 and 20 μm, as well as reduced apoptosis by 47.1% (P < 0.001) and 41.3% (P < 0.01), respectively. Finally, honokiol reduced senescence-associated β-galactosidase expression in HFF-1.

CONCLUSION

Honokiol protects both HFF-1 and HaCat against cigarette smoke-induced inflammation, collagenolysis, apoptosis, and senescence.

Vapours of US and EU Market Leader Electronic Cigarette Brands and Liquids Are Cytotoxic for Human Vascular Endothelial Cells

The present study was conducted to provide toxicological data on e-cigarette vapours of different e-cigarette brands and liquids from systems viewed as leaders in the e-cigarette market and to compare e-cigarette vapour toxicity to the toxicity of conventional strong high-nicotine cigarette smoke. Using an adapted version of a previously constructed cigarette smoke constituent sampling device, we collected the hydrophilic fraction of e-cigarette vapour and exposed human umbilical vein endothelial cells (HUVECs) to the mixture of compounds present in the vapour of 4 different single-use e-cigarettes, 6 different liquid vapours produced by the same refillable e-cigarette, and one e-cigarette with an exchangeable liquid cartridge. After incubation of cells with various concentrations and for various periods of time we analysed cell death induction, proliferation rates, the occurrence of intra-cellular reactive oxygen species, cell morphology, and we also measured e-cigarette heating coil temperatures. Overall, conventional cigarette smoke extract showed the most severe impact on endothelial cells. However, some e-cigarette vapour extracts showed high cytotoxicity, inhibition of cell proliferation, and alterations in cell morphology, which were comparable to conventional high-nicotine cigarettes. The vapours generated from different liquids using the same e-cigarette show substantial differences, pointing to the liquids as an important source for toxicity. E-cigarette vapour-mediated induction of oxidative stress was significant in one out of the 11 analysed vapours. There is a high variability in the acute cytotoxicity of e-cigarette vapours depending on the liquid and on the e-cigarettes used. Some products showed toxic effects close to a conventional high-nicotine cigarette. Liquid nicotine, menthol content, and the formation of acute intracellular reactive oxygen species do not seem to be the central elements in e-cigarette vapour toxicity.

Cardiovascular Effects of Exposure to Cigarette Smoke and Electronic Cigarettes: Clinical Perspectives From the Prevention of Cardiovascular Disease Section Leadership Council and Early Career Councils of the American College of Cardiology

Cardiovascular morbidity and mortality as a result of inhaled tobacco products continues to be a global healthcare crisis, particularly in low- and middle-income nations lacking the infrastructure to develop and implement effective public health policies limiting tobacco use. Following initiation of public awareness campaigns 50 years ago in the United States, considerable success has been achieved in reducing the prevalence of cigarette smoking and exposure to secondhand smoke. However, there has been a slowing of cessation rates in the United States during recent years, possibly caused by high residual addiction or fatigue from cessation messaging. Furthermore, tobacco products have continued to evolve faster than the scientific understanding of their biological effects. This review considers selected updates on the genetics and epigenetics of smoking behavior and associated cardiovascular risk, mechanisms of atherogenesis and thrombosis, clinical effects of smoking and benefits of cessation, and potential impact of electronic cigarettes on cardiovascular health.