N-acetyl cysteine reverts the proinflammatory state induced by cigarette smoke extract in lung Calu-3 cells

Revisiting airway epithelial dysfunction and mechanisms in chronic obstructive pulmonary disease: the role of mitochondrial damage

Chronic exposure to environmental hazards causes airway epithelial dysfunction, primarily impaired physical barriers, immune dysfunction, and repair or regeneration. Impairment of airway epithelial function subsequently leads to exaggerated airway inflammation and remodeling, the main features of chronic obstructive pulmonary disease (COPD). Mitochondrial damage has been identified as one of the mechanisms of airway abnormalities in COPD, which is closely related to airway inflammation and airflow limitation. In this review, we evaluate updated evidence for airway epithelial mitochondrial damage in COPD and focus on the role of mitochondrial damage in airway epithelial dysfunction. In addition, the possible mechanism of airway epithelial dysfunction mediated by mitochondrial damage is discussed in detail, and recent strategies related to airway epithelial-targeted mitochondrial therapy are summarized. Results have shown that dysregulation of mitochondrial quality and oxidative stress may lead to airway epithelial dysfunction in COPD. This may result from mitochondrial damage as a central organelle mediating abnormalities in cellular metabolism. Mitochondrial damage mediates procellular senescence effects due to mitochondrial reactive oxygen species, which effectively exacerbate different types of programmed cell death, participate in lipid metabolism abnormalities, and ultimately promote airway epithelial dysfunction and trigger COPD airway abnormalities. These can be prevented by targeting mitochondrial damage factors and mitochondrial transfer. Thus, because mitochondrial damage is involved in COPD progression as a central factor of homeostatic imbalance in airway epithelial cells, it may be a novel target for therapeutic intervention to restore airway epithelial integrity and function in COPD.

NLRP10 promotes AGEs-induced NLRP1 and NLRP3 inflammasome activation via ROS/MAPK/NF-κB signaling in human periodontal ligament cells

Diabetes mellitus (DM), characterized by production and accumulation of advanced glycation end products (AGEs), induces and promotes chronic inflammation in tissues, including periodontal tissue. Increasing amount of epidemiological and experimental evidence demonstrated that more extensive inflammatory reaction and bone resorption occurred in periodontal tissues in diabetic patients with periodontitis, which is speculated to be related to NLRP3 inflammasome. NLRP10 is the only NOD-like receptor protein lacking leucine-rich repeats, suggesting that NLRP10 may be a regulatory protein. The aim of this study was to investigate the regulatory role of NLRP10 on NLRP1 and NLRP3 inflammasome in human periodontal ligament cells (HPDLCs) under AGEs treatment. Expression of NLRP10 in HPDLCs stimulated with 100 ug/mL AGEs for 24 h was observed. Detection of TRIM31 is conducted, and in TRIM31-overexpressed HPDLCs, the interaction between NLRP10 with TRIM31 as well as NLRP10 with ubiquitination were explored by immunoprecipitation. Under AGEs stimulation, the activation of reactive oxidative stress (ROS) and inflammatory signaling pathway (NF-κB, MAPK pathway) was detected by biomedical microscope and western blot (WB), respectively. After stimulation with AGEs for 24 h with or without silencing NLRP10, inflammatory cytokines (IL-6 and IL-1β), NF-κB, MAPK pathway, ROS, and components of inflammasome were assessed. In HPDLCs, we found AGEs induced NLRP10 and inhibited TRIM31. TRIM31 overexpression significantly enhanced interaction between TRIM31 and NLRP10, then induced proteasomal degradation of NLRP10. Moreover, under AGEs stimulation, NLRP10 positively regulates NLRP1, NLRP3 inflammasomes by activating NF-κB, MAPK pathway, and increasing ROS, finally promoting the expression of inflammatory cytokines. Together, we, for the first time, confirmed that NLRP10 could promote inflammatory response induced by AGEs in HPDLCs via activation of NF-κB, and MAPK pathway and increasing ROS.

Influence of dose and exposition time in the effectiveness of N-Acetyl-l-cysteine treatment in A549 human epithelial cells

N-Acetyl-l-cysteine (NAC) acts as a precursor of the tripeptide glutathione (GSH), one of the principal cell mechanisms for reactive oxygen species (ROS) detoxification. Chronic obstructive pulmonary disease (COPD) is associated with enhanced inflammatory response and oxidative stress and NAC has been used to suppress various pathogenic processes in this disease. Studies show that the effects of NAC are dose-dependent, and it appears that the efficient doses in vitro are usually higher than the achieved in vivo plasma concentrations. However, to date, the inconsistencies between the in vitro NAC antioxidant and anti-inflammatory in vitro effects, by reproducing the in vivo NAC plasma concentrations as well as high NAC concentrations. To do so, A549 were transfected with polyinosinic-polycytidylic acid (Poly (I:C)) and treated with NAC at different treatment periods. Oxidative stress, release of proinflammatory mediators and NFkB activation were analyzed. Results suggest that NAC at low doses in chronic administration has sustained antioxidant and anti-inflammatory effects, while acute treatment with high dose NAC exerts a strong antioxidant and anti-inflammatory response.

Vx-809, a CFTR Corrector, Acts through a General Mechanism of Protein Folding and on the Inflammatory Process

Correct protein folding is the basis of cellular well-being; thus, accumulation of misfolded proteins within the endoplasmic reticulum (ER) leads to an imbalance of homeostasis that causes stress to the ER. Various studies have shown that protein misfolding is a significant factor in the etiology of many human diseases, including cancer, diabetes, and cystic fibrosis. Misfolded protein accumulation in the ER triggers a sophisticated signal transduction pathway, the unfolded protein response (UPR), which is controlled by three proteins, resident in ER: IRE1α, PERK, and ATF6. Briefly, when ER stress is irreversible, IRE1α induces the activation of pro-inflammatory proteins; PERK phosphorylates eIF2α which induces ATF4 transcription, while ATF6 activates genes encoding ER chaperones. Reticular stress causes an alteration of the calcium homeostasis, which is released from the ER and taken up by the mitochondria, leading to an increase in the oxygen radical species production, and consequently, to oxidative stress. Accumulation of intracellular calcium, in combination with lethal ROS levels, has been associated with an increase of pro-inflammatory protein expression and the initiation of the inflammatory process. Lumacaftor (Vx-809) is a common corrector used in cystic fibrosis treatment which enhances the folding of mutated F508del-CFTR, one of the most prevalent impaired proteins underlying the disease, promoting a higher localization of the mutant protein on the cell membrane. Here, we demonstrate that this drug reduces the ER stress and, consequently, the inflammation that is caused by such events. Thus, this molecule is a promising drug to treat several pathologies that present an etiopathogenesis due to the accumulation of protein aggregates that lead to chronic reticular stress.

Disruption of the Molecular Regulation of Mitochondrial Metabolism in Airway and Lung Epithelial Cells by Cigarette Smoke: Are Aldehydes the Culprit?

Chronic obstructive pulmonary disease (COPD) is a devastating lung disease for which cigarette smoking is the main risk factor. Acetaldehyde, acrolein, and formaldehyde are short-chain aldehydes known to be formed during pyrolysis and combustion of tobacco and have been linked to respiratory toxicity. Mitochondrial dysfunction is suggested to be mechanistically and causally involved in the pathogenesis of smoking-associated lung diseases such as COPD. Cigarette smoke (CS) has been shown to impair the molecular regulation of mitochondrial metabolism and content in epithelial cells of the airways and lungs. Although it is unknown which specific chemicals present in CS are responsible for this, it has been suggested that aldehydes may be involved. Therefore, it has been proposed by the World Health Organization to regulate aldehydes in commercially-available cigarettes. In this review, we comprehensively describe and discuss the impact of acetaldehyde, acrolein, and formaldehyde on mitochondrial function and content and the molecular pathways controlling this (biogenesis versus mitophagy) in epithelial cells of the airways and lungs. In addition, potential therapeutic applications targeting (aldehyde-induced) mitochondrial dysfunction, as well as regulatory implications, and the necessary required future studies to provide scientific support for this regulation, have been covered in this review.

Smoking-Associated Exposure of Human Primary Bronchial Epithelial Cells to Aldehydes: Impact on Molecular Mechanisms Controlling Mitochondrial Content and Function

Chronic obstructive pulmonary disease (COPD) is a devastating lung disease primarily caused by exposure to cigarette smoke (CS). During the pyrolysis and combustion of tobacco, reactive aldehydes such as acetaldehyde, acrolein, and formaldehyde are formed, which are known to be involved in respiratory toxicity. Although CS-induced mitochondrial dysfunction has been implicated in the pathophysiology of COPD, the role of aldehydes therein is incompletely understood. To investigate this, we used a physiologically relevant in vitro exposure model of differentiated human primary bronchial epithelial cells (PBEC) exposed to CS (one cigarette) or a mixture of acetaldehyde, acrolein, and formaldehyde (at relevant concentrations of one cigarette) or air, in a continuous flow system using a puff-like exposure protocol. Exposure of PBEC to CS resulted in elevated IL-8 cytokine and mRNA levels, increased abundance of constituents associated with autophagy, decreased protein levels of molecules associated with the mitophagy machinery, and alterations in the abundance of regulators of mitochondrial biogenesis. Furthermore, decreased transcript levels of basal epithelial cell marker KRT5 were reported after CS exposure. Only parts of these changes were replicated in PBEC upon exposure to a combination of acetaldehyde, acrolein, and formaldehyde. More specifically, aldehydes decreased MAP1LC3A mRNA (autophagy) and BNIP3 protein (mitophagy) and increased ESRRA protein (mitochondrial biogenesis). These data suggest that other compounds in addition to aldehydes in CS contribute to CS-induced dysregulation of constituents controlling mitochondrial content and function in airway epithelial cells.

Treatment with Bixin-Loaded Polymeric Nanoparticles Prevents Cigarette Smoke-Induced Acute Lung Inflammation and Oxidative Stress in Mice

The use of annatto pigments has been evaluated as a therapeutic strategy in animal models of several health disorders. Beneficial effects were generally attributed to the inhibition of oxidative stress. Bixin is the main pigment present in annatto seeds and has emerged as an important scavenger of reactive oxygen (ROS) and nitrogen species (RNS). However, this carotenoid is highly hydrophobic, affecting its therapeutic applicability. Therefore, bixin represents an attractive target for nanotechnology to improve its pharmacokinetic parameters. In this study, we prepared bixin nanoparticles (npBX) and evaluated if they could prevent pulmonary inflammation and oxidative stress induced by cigarette smoke (CS). C57BL/6 mice were exposed to CS and treated daily (by gavage) with different concentrations of npBX (6, 12 and 18%) or blank nanoparticles (npBL, 18%). The negative control group was sham smoked and received 18% npBL. On day 6, the animals were euthanized, and bronchoalveolar lavage fluid (BALF), as well as lungs, were collected for analysis. CS exposure led to an increase in ROS and nitrite production, which was absent in animals treated with npBX. In addition, npBX treatment significantly reduced leukocyte numbers and TNF-α levels in the BALF of CS-exposed mice, and it strongly inhibited CS-induced increases in MDA and PNK in lung homogenates. Interestingly, npBX protective effects against oxidative stress seemed not to act via Nrf2 activation in the CS + npBX 18% group. In conclusion, npBX prevented oxidative stress and acute lung inflammation in a murine model of CS-induced acute lung inflammation.

Synergistic induction of IL-6 production in human bronchial epithelial cells in vitro by nickel nanoparticles and lipopolysaccharide is mediated by STAT3 and C/EBPβ

We previously reported that delivery of nickel nanoparticles (NiNPs) and bacterial lipopolysaccharide (LPS) into the lungs of mice synergistically increased IL-6 production and inflammation, and male mice were more susceptible than female mice. The primary goal of this study was to utilize an in vitro human lung epithelial cell model (BEAS-2B) to investigate the intracellular signaling mechanisms that mediate IL-6 production by LPS and NiNPs. We also investigated the effect of sex hormones on NiNP and LPS-induced IL-6 production in vitro. LPS and NiNPs synergistically induced IL-6 mRNA and protein in BEAS-2B cells. TPCA-1, a dual inhibitor of IKK-2 and STAT3, blocked the synergistic increase in IL-6 caused by LPS and NiNPs, abolished STAT3 activation, and reduced C/EBPβ. Conversely, SC144, an inhibitor of the gp130 component of the IL-6 receptor, enhanced IL-6 production induced by LPS and NiNPs. Treatment of BEAS-2B cells with sex hormones (17β-estradiol, progesterone, or testosterone) or the anti-oxidant NAC, had no effect on IL-6 induction by LPS and NiNPs. These data suggest that LPS and NiNPs induce IL-6 via STAT3 and C/EBPβ in BEAS-2B cells. While BEAS-2B cells are a suitable model to study mechanisms of IL-6 production, they do not appear to be suitable for studying the effect of sex hormones.

Dysregulated mitochondrial metabolism upon cigarette smoke exposure in various human bronchial epithelial cell models

Exposure to cigarette smoke (CS) is the primary risk factor for developing chronic obstructive pulmonary disease. The impact of CS exposure on the molecular mechanisms involved in mitochondrial quality control in airway epithelial cells is incompletely understood. Undifferentiated or differentiated primary bronchial epithelial cells were acutely/chronically exposed to whole CS (WCS) or CS extract (CSE) in submerged or air-liquid interface conditions. Abundance of key regulators controlling mitochondrial biogenesis, mitophagy and mitochondrial dynamics was assessed. Acute exposure to WCS or CSE increased the abundance of components of autophagy and receptor-mediated mitophagy in all models. Although mitochondrial content and dynamics appeared to be unaltered in response to CS, changes in both the molecular control of mitochondrial biogenesis and a shift toward an increased glycolytic metabolism were observed in particular in differentiated cultures. These alterations persisted, at least in part, after chronic exposure to WCS during differentiation and upon subsequent discontinuation of WCS exposure. In conclusion, smoke exposure alters the regulation of mitochondrial metabolism in airway epithelial cells, but observed alterations may differ between various culture models used. This article has an associated First Person interview with the joint first authors of the paper.

NLR family pyrin domain containing 3 (NLRP3) and caspase 1 (CASP1) modulation by intracellular Cl- concentration

The impairment of the cystic fibrosis transmembrane conductance regulator (CFTR) activity induces intracellular chloride (Cl- ) accumulation. The anion Cl- , acting as a second messenger, stimulates the secretion of interleukin-1β (IL-1β), which starts an autocrine positive feedback loop. Here, we show that NLR family pyrin domain containing 3 (NLRP3) and caspase 1 (CASP1) are indirectly modulated by the intracellular Cl- concentration, showing maximal expression and activity at 75 mM Cl- , in the presence of the ionophores nigericin and tributyltin. The expression of PYD and CARD domain containing (PYCARD/ASC) remained constant from 0 to 125 mM Cl- . The CASP1 inhibitor VX-765 and the NLRP3 inflammasome inhibitor MCC950 completely blocked the Cl- -stimulated IL-1β mRNA expression and partially the IL-1β secretion. DCF fluorescence (cellular reactive oxygen species, cROS) and MitoSOX fluorescence (mitochondrial ROS, mtROS) also showed maximal ROS levels at 75 mM Cl- , a response strongly inhibited by the ROS scavenger N-acetyl-L-cysteine (NAC) or the NADPH oxidase (NOX) inhibitor GKT137831. These inhibitors also affected CASP1 and NLRP3 mRNA and protein expression. More importantly, the serum/glucocorticoid regulated kinase 1 (SGK1) inhibitor GSK650394, or its shRNAs, completely abrogated the IL-1β mRNA response to Cl- and the IL-1β secretion, interrupting the autocrine IL-1β loop. The results suggest that Cl- effects are mediated by SGK1, in which under Cl- modulation stimulates the secretion of mature IL-1β, in turn, responsible for the upregulation of ROS, CASP1, NLRP3 and IL-1β itself, through autocrine signalling.

Lumacaftor and Matrine: Possible Therapeutic Combination to Counteract the Inflammatory Process in Cystic Fibrosis

Cystic fibrosis is a monogenic, autosomal, recessive disease characterized by an alteration of chloride transport caused by mutations in the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) gene. The loss of Phe residue in position 508 (ΔF508-CFTR) causes an incorrect folding of the protein causing its degradation and electrolyte imbalance. CF patients are extremely predisposed to the development of a chronic inflammatory process of the bronchopulmonary system. When the cells of a tissue are damaged, the immune cells are activated and trigger the production of free radicals, provoking an inflammatory process. In addition to routine therapies, today drugs called correctors are available for mutations such as ΔF508-CFTR as well as for others less frequent ones. These active molecules are supposed to facilitate the maturation of the mutant CFTR protein, allowing it to reach the apical membrane of the epithelial cell. Matrine induces ΔF508-CFTR release from the endoplasmic reticulum to cell cytosol and its localization on the cell membrane. We now have evidence that Matrine and Lumacaftor not only restore the transport of mutant CFTR protein, but probably also counteract the inflammatory process by improving the course of the disease.

Effects of N-acetyl cysteine on mitochondrial ROS, mitochondrial dynamics, and inflammation on lipopolysaccharide-treated human apical papilla cells

OBJECTIVES

N-Acetyl cysteine (NAC), a well-known antioxidant molecule, has been used to modulate oxidative stress and inflammation. However, no studies have examined the effect of NAC in regenerative endodontic procedures (REPs). Therefore, the aim of this study was to investigate the effects of NAC on cell survival, mitochondrial reactive oxygen species (mtROS) production, and inflammatory and mitochondria-related gene expression on lipopolysaccharide (LPS)-treated apical papilla cells (APCs).

MATERIALS AND METHODS

To assess the NAC concentration, 5 and 10 mM NAC were administered to LPS-treated APCs. Cell proliferation was measured at 24, 48, and 72 h by using AlamarBlue® assay. The 5-mM concentration was further analyzed using different treatment durations: 10 min, 24 h, and the entire study period. The mtROS production was quantified using MitoSOX™ Red and MitoTracker™ Green. RT-PCR was used to detect the expression of IL-6 and TNF-α inflammatory genes and mitochondrial morphology-related genes (Mfn-2/Drp-1 and Bcl-2/Bax) at 6 and 24 h. The statistical significance level was set at 0.05.

RESULTS

Five-millimolar NAC promoted the highest LPS-treated APC proliferation. The use of 24-h NAC stimulated cell proliferation, whereas the entire-period NAC application (> 48 h) significantly reduced the cell number. The mtROS levels were slightly altered after NAC induction. Ten-minute NAC treatment downregulated the IL-6 and TNF-α expression, whereas the expression of Bcl-2/Bax and Mfn-2/Drp-1 ratios was upregulated at 6 h.

CONCLUSIONS

Under the LPS-induced inflammatory condition, NAC stimulated APC survival and decreased inflammation. Ten-minute NAC treatment was sufficient to reduce the level of inflammation and maintain the mitochondrial dynamics.

CLINICAL RELEVANCE

Ten-minute NAC application is sufficient to reduce the level of inflammation and maintain the mitochondrial dynamics. Therefore, NAC may be considered as a potential adjunctive irrigation solution in REPs.

Retrograde signaling by a mtDNA-encoded non-coding RNA preserves mitochondrial bioenergetics

Alveolar epithelial type II (AETII) cells are important for lung epithelium maintenance and function. We demonstrate that AETII cells from mouse lungs exposed to cigarette smoke (CS) increase the levels of the mitochondria-encoded non-coding RNA, mito-RNA-805, generated by the control region of the mitochondrial genome. The protective effects of mito-ncR-805 are associated with positive regulation of mitochondrial energy metabolism, and respiration. Levels of mito-ncR-805 do not relate to steady-state transcription or replication of the mitochondrial genome. Instead, CS-exposure causes the redistribution of mito-ncR-805 from mitochondria to the nucleus, which correlated with the increased expression of nuclear-encoded genes involved in mitochondrial function. These studies reveal an unrecognized mitochondria stress associated retrograde signaling, and put forward the idea that mito-ncRNA-805 represents a subtype of small non coding RNAs that are regulated in a tissue- or cell-type specific manner to protect cells under physiological stress.

Development of a Carrier-Free Dry Powder Ofloxacin Formulation With Enhanced Aerosolization Properties

Tuberculosis (TB) is a serious infectious disease that affects more than new 10 million patients each year. Many of these cases are resistant to first-line drugs so second-line ones, like fluoroquinolones, need to be incorporated into the therapeutic. Ofloxacin (OF) is a fluoroquinolone which demonstrates high antibiotic activity against the bacteria that causes TB (M. tuberculosis). In this work, ionic complexes, composed by hyaluronic acid (HA) and OF, with different neutralization degrees, were prepared and processed by spray drying (SD) to obtain powders for inhalatory administration. Combining a formulation with high neutralization degree, high SD atomization air flowrate and the use of a high-performance collection cyclone, very good process yields were obtained. Carrier-free formulations with a loading of 0.39-0.46 g_OF/g_powder showed excellent emitted, fine particle, and respirable fractions for capsule loadings of 25 and 100 mg. The ionic complexes demonstrated higher mucoadhesion than pure OF and HA. The best formulation did not affect CALU-3 cell viability up to a dose 6.5 times higher than the MIC₉₀ reported to treat multi-drug resistant TB.

Mitochondria: at the crossroads of regulating lung epithelial cell function in chronic obstructive pulmonary disease

Disturbances in mitochondrial structure and function in lung epithelial cells have been implicated in the pathogenesis of various lung diseases, including chronic obstructive pulmonary disease (COPD). Such disturbances affect not only cellular energy metabolism but also alter a range of indispensable cellular homeostatic functions in which mitochondria are known to be involved. These range from cellular differentiation, cell death pathways, and cellular remodeling to physical barrier function and innate immunity, all of which are known to be impacted by exposure to cigarette smoke and have been linked to COPD pathogenesis. Next to their well-established role as the first physical frontline against external insults, lung epithelial cells are immunologically active. Malfunctioning epithelial cells with defective mitochondria are unable to maintain homeostasis and respond adequately to further stress or injury, which may ultimately shape the phenotype of lung diseases. In this review, we provide a comprehensive overview of the impact of cigarette smoke on the development of mitochondrial dysfunction in the lung epithelium and highlight the consequences for cell function, innate immune responses, epithelial remodeling, and epithelial barrier function in COPD. We also discuss the applicability and potential therapeutic value of recently proposed strategies for the restoration of mitochondrial function in the treatment of COPD.

The effect of NLRP inflammasome on the regulation of AGEs-induced inflammatory response in human periodontal ligament cells

BACKGROUND AND OBJECTIVE

Diabetes influences the frequency and development of periodontitis. Inflammation of human periodontal ligament cells (HPDLCs) participates in this pathologic process. Hence, this study aims to explore whether advanced glycation end products (AGEs), by-products of diabetes, could exaggerate inflammation induced by muramyl dipeptide (MDP) in HPDLCs, and whether nucleotide-binding oligomerization domain-like receptors (NLRs) signaling pathway was involved.

MATERIAL AND METHODS

Human periodontal ligament cells were pre-treated with 100 μg/mL AGEs for 24 hours and stimulated with 10 μg/mL MDP for 24 hours. IL-6, IL-1β, and RAGE were detected, and the activation of NF-κB signaling pathway was observed. The expression of NLRs was evaluated with or without silencing RAGE or blocking NF-κB pathway under AGEs stimulation. Statistical analyses were performed by using independent sample t test.

RESULTS

Advanced glycation end products induced significant increase of inflammatory cytokines in HPDLCs (P < 0.05). Results of western blot (WB) showed that after 45 minutes stimulation of AGEs, p-p65/p65 ratio peaked; AGEs promoted the expression of NLRP1, NLRP3, and apoptosis-associated speck-like protein containing a CARD (ASC). After silencing RAGE or blocking NF-κB pathway, the up-regulation of NLRs protein caused by AGEs was attenuated. Additionally, AGEs pre-treatment could enhance the inflammatory response of MDP and the expression of NLRs, which were demonstrated by more expression of IL-6, IL-1β, NOD2, NLRP1, NLRP3, and ASC.

CONCLUSION

Advanced glycation end products induced inflammatory response in HPDLCs via NLRP1-inflammasome and NLRP3-inflammasome activation in which NF-κB signal pathway was involved. Besides, AGEs promoted the inflammatory response of MDP via NOD2, NLRP1-inflammasome, and NLRP3-inflammasome.

Modeling cellular metabolomic effects of oxidative stress impacts from hydrogen peroxide and cigarette smoke on human lung epithelial cells

The respiratory system is continuously exposed to variety of biological and chemical irritants that contain reactive oxygen species, and these are well known to cause oxidative stress responses in lung epithelial cells. There is a clinical need to identify biomarkers of oxidative stress which could potentially support early indicators of disease and health management. To identify volatile biomarkers of oxidative stress, we analyzed the headspace above human bronchial epithelial cell cultures (HBE1) before and after hydrogen peroxide (H₂O₂) and cigarette smoke extract (CSE) exposure. Using stir bar and headspace sorptive extraction-gas chromatography-mass spectrometry, we searched for volatile organic compounds (VOC) of these oxidative measures. In the H₂O₂ cell peroxidation experiments, four different H₂O₂ concentrations (0.1, 0.5, 10, 50 mM) were applied to the HBE1 cells, and VOCs were collected every 12 h over the time course of 48 h. In the CSE cell peroxidation experiments, four different smoke extract concentrations (0%, 10%, 30%, 60%) were applied to the cells, and VOCs were collected every 12 h over the time course of 48 h. We used partial-least squares (PLS) analysis to identify putative compounds from the mass spectrometry results that highly correlated with the known applied oxidative stress. We observed chemical emissions from the cells that related to both the intensity of the oxidative stress and followed distinct time courses. Additionally, some of these chemicals are aldehydes, which are thought to be non-invasive indicators of oxidative stress in exhaled human breath. Together, these results illustrate a powerful in situ cell culture model of oxidative stress that can be used to explore the putative biological genesis of exhaled breath biomarkers that are often observed in human clinical studies.

Novel curcumin analogue hybrids: Synthesis and anticancer activity

In this study, twenty curcumin analogue hybrids as potential anticancer agents through regulation protein of TrxR were designed and synthesized. Results of anticancer activity showed that 5,7-dimethoxy-3-(3-(2-((1E, 4E)-3-oxo-5-(pyridin-2-yl)penta-1,4-dien-1- yl)phenoxy)propoxy)-2-(3,4,5-trimethoxyphenyl)-4H-chromen-4-one (compound 7d) could induce gastric cancer cells apoptosis by arresting cell cycle, break mitochondria function and inhibit TrxR activity. Meanwhile, western blot revealed that this compound could dramatically up expression of Bax/Bcl-2 ratio and high expression of TrxR oxidation. These results preliminarily show that the important role of ROS mediated activation of ASK1/MAPK signaling pathways by this title compound.