Thioredoxin-1 suppresses lung injury and apoptosis induced by diesel exhaust particles (DEP) by scavenging reactive oxygen species and by inhibiting DEP-induced downregulation of Akt

Thioredoxin-1 Ameliorates Oxygen-Induced Retinopathy in Newborn Mice Through Modulation of Proinflammatory and Angiogenic Factors

Oxygen-induced retinopathy (OIR) is an animal model for retinopathy of prematurity, which is a leading cause of blindness in children. Thioredoxin-1 (TRX) is a small redox protein that has cytoprotective and anti-inflammatory properties in response to oxidative stress. The purpose of this study was to determine the effect of TRX on OIR in newborn mice. From postnatal day 7, C57BL/6 wild type (WT) and TRX transgenic (TRX-Tg) mice were exposed to either 21% or 75% oxygen for 5 days. Avascular and neovascular regions of the retinas were investigated using fluorescence immunostaining. Fluorescein isothiocyanate-dextran and Hoechst staining were used to measure retinal vascular leakage. mRNA expression levels of proinflammatory and angiogenic factors were analyzed using quantitative polymerase chain reaction. Retinal histological changes were detected using immunohistochemistry. In room air, the WT mice developed well-organized retinas. In contrast, exposing WT newborn mice to hyperoxia hampered retinal development, increasing the retinal avascular and neovascular areas. After hyperoxia exposure, TRX-Tg mice had enhanced retinal avascularization compared with WT mice. TRX-Tg mice had lower retinal neovascularization and retinal permeability during recovery from hyperoxia compared with WT mice. In the early stages after hyperoxia exposure, VEGF-A and CXCL-2 expression levels decreased, while IL-6 expression levels increased in WT newborn mice. Conversely, no differences in gene expressions were observed in the TRX-Tg mouse retina. IGF-1 and Angpt1 levels did not decrease during recovery from hyperoxia in TRX-Tg newborn mice. As a result, overexpression of TRX improves OIR in newborn mice by modulating proinflammatory and angiogenic factors.

Nitroxyl Radical as a Theranostic Contrast Agent in Magnetic Resonance Redox Imaging

Significance:In vivo assessment of paramagnetic and diamagnetic conversions of nitroxyl radicals based on cyclic redox mechanism can be an index of tissue redox status. The redox mechanism of nitroxyl radicals, which enables their use as a normal tissue-selective radioprotector, is seen as being attractive on planning radiation therapy. Recent Advances:In vivo redox imaging using nitroxyl radicals as redox-sensitive contrast agents has been developed to assess tissue redox status. Chemical and biological behaviors depending on chemical structures of nitroxyl radical compounds have been understood in detail. Polymer types of nitroxyl radical contrast agents and/or nitroxyl radical-labeled drugs were designed for approaching theranostics. Critical Issues: Nitroxyl radicals as magnetic resonance imaging (MRI) contrast agents have several advantages compared with those used in electron paramagnetic resonance (EPR) imaging, while support by EPR spectroscopy is important to understand information from MRI. Redox-sensitive paramagnetic contrast agents having a medicinal benefit, that is, nitroxyl-labeled drug, have been developed and proposed. Future Directions: A development of suitable nitroxyl contrast agent for translational theranostic applications with high reaction specificity and low normal tissue toxicity is under progress. Nitroxyl radicals as redox-sensitive magnetic resonance contrast agents can be a useful tool to detect an abnormal tissue redox status such as disordered oxidative stress. Antioxid. Redox Signal. 36, 95-121.

Protective Role of Transduced Tat-Thioredoxin1 (Trx1) against Oxidative Stress-Induced Neuronal Cell Death via ASK1-MAPK Signal Pathway

Oxidative stress plays a crucial role in the development of neuronal disorders including brain ischemic injury. Thioredoxin 1 (Trx1), a 12 kDa oxidoreductase, has anti-oxidant and anti-apoptotic functions in various cells. It has been highly implicated in brain ischemic injury. However, the protective mechanism of Trx1 against hippocampal neuronal cell death is not identified yet. Using a cell permeable Tat-Trx1 protein, protective mechanism of Trx1 against hydrogen peroxide-induced cell death was examined using HT-22 cells and an ischemic animal model. Transduced Tat-Trx1 markedly inhibited intracellular ROS levels, DNA fragmentation, and cell death in H₂O₂-treatment HT-22 cells. Tat-Trx1 also significantly inhibited phosphorylation of ASK1 and MAPKs in signaling pathways of HT-22 cells. In addition, Tat-Trx1 regulated expression levels of Akt, NF-κB, and apoptosis related proteins. In an ischemia animal model, Tat-Trx1 markedly protected hippocampal neuronal cell death and reduced astrocytes and microglia activation. These findings indicate that transduced Tat-Trx1 might be a potential therapeutic agent for treating ischemic injury.

Combined Toxicity of Metal Nanoparticles: Comparison of Individual and Mixture Particles Effect

Toxicity of metal nanoparticles (NPs) are closely associated with increasing intracellular reactive oxygen species (ROS) and the levels of pro-inflammatory mediators. However, NP interactions and surface complexation reactions alter the original toxicity of individual NPs. To date, toxicity studies on NPs have mostly been focused on individual NPs instead of the combination of several species. It is expected that the amount of industrial and highway-acquired NPs released into the environment will further increase in the near future. This raises the possibility that various types of NPs could be found in the same medium, thereby, the adverse effects of each NP either could be potentiated, inhibited or remain unaffected by the presence of the other NPs. After uptake of NPs into the human body from various routes, protein kinases pathways mediate their toxicities. In this context, family of mitogen-activated protein kinases (MAPKs) is mostly efficient. Despite each NP activates almost the same metabolic pathways, the toxicity induced by a single type of NP is different than the case of co-exposure to the combined NPs. The scantiness of toxicological data on NPs combinations displays difficulties to determine, if there is any risk associated with exposure to combined nanomaterials. Currently, in addition to mathematical analysis (Response surface methodology; RSM), the quantitative-structure-activity relationship (QSAR) is used to estimate the toxicity of various metal oxide NPs based on their physicochemical properties and levels applied. In this chapter, it is discussed whether the coexistence of multiple metal NPs alter the original toxicity of individual NP. Additionally, in the part of "Toxicity of diesel emission/exhaust particles (DEP)", the known individual toxicity of metal NPs within the DEP is compared with the data regarding toxicity of total DEP mixture.

Attenuation of Hyperoxic Lung Injury in Newborn Thioredoxin-1-Overexpressing Mice through the Suppression of Proinflammatory Cytokine mRNA Expression

The role of thioredoxin-1 (TRX), a small redox-active protein with antioxidant effects, during hyperoxic lung injury in newborns remains undetermined. We investigated TRX impact on hyperoxic lung injury in newborn TRX transgenic (TRX-Tg) and wildtype (WT) mice exposed to 21% or 95% O₂ for four days, after which some mice were allowed to recover in room air for up to 14 days. Lung morphology was assessed by hematoxylin/eosin and elastin staining, as well as immunostaining for macrophages. The gene expression levels of proinflammatory cytokines were evaluated using quantitative real-time polymerase chain reaction. During recovery from hyperoxia, TRX-Tg mice exhibited an improved mean linear intercept length and increased number of secondary septa in lungs compared with the WT mice. Neonatal hyperoxia enhanced the mRNA expression levels of proinflammatory cytokines in the lungs of both TRX-Tg and WT mice. However, interleukin-6, monocyte chemoattractant protein-1, and chemokine (C-X-C motif) ligand 2 mRNA expression levels were reduced in the lungs of TRX-Tg mice compared with the WT mice during recovery from hyperoxia. Furthermore, TRX-Tg mice exhibited reduced macrophage infiltration in lungs during recovery. These results suggest that in newborn mice TRX ameliorates hyperoxic lung injury during recovery likely through the suppression of proinflammatory cytokines.

Novel thioredoxin reductase inhibitor butaselen inhibits tumorigenesis by down-regulating programmed death-ligand 1 expression

The thioredoxin system plays a role in a variety of physiological functions, including cell growth, differentiation, apoptosis, tumorigenesis, and immunity. We previously confirmed that butaselen (BS), a novel thioredoxin reductase inhibitor, can inhibit the growth of various human cancer cell lines, yet the underlying mechanism remains elusive. In this study, we investigated the anti-tumor effect of BS in vivo through regulating the immune system of KM mice. We found that BS inhibits tumor proliferation by promoting the activation of splenic lymphocytes in mice. BS can elevate the percentage of CD₄^-CD₈⁺ T lymphocytes and the secretion of downstream cytokines in mice via down-regulating the expression of programmed death-ligand 1 (PD-L1) on the tumor cells' surface in vivo. Further study in HepG2 and BEL-7402 cells showed that decrease of PD-L1 level after BS treatment was achieved by inhibiting signal transducer and activator of transcription 3 (STAT3) phosphorylation. Taken together, our results suggest that BS has a role in promoting the immune response by reducing PD-L1 expression via the STAT3 pathway, and subsequently suppresses tumorigenesis.

Multi-cellular human bronchial models exposed to diesel exhaust particles: assessment of inflammation, oxidative stress and macrophage polarization

Background

Diesel exhaust particles (DEP) are a major component of outdoor air pollution. DEP mediated pulmonary effects are plausibly linked to inflammatory and oxidative stress response in which macrophages (MQ), epithelial cells and their cell-cell interaction plays a crucial role. Therefore, in this study we aimed at studying the cellular crosstalk between airway epithelial cells with MQ and MQ polarization following exposure to aerosolized DEP by assessing inflammation, oxidative stress, and MQ polarization response markers.

Method

Lung mucosa models including primary bronchial epithelial cells (PBEC) cultured at air-liquid interface (ALI) were co-cultured without (PBEC-ALI) and with MQ (PBEC-ALI/MQ). Cells were exposed to 12.7 μg/cm² aerosolized DEP using XposeALI^®. Control (sham) models were exposed to clean air. Cell viability was assessed. CXCL8 and IL-6 were measured in the basal medium by ELISA. The mRNA expression of inflammatory markers (CXCL8, IL6, TNFα), oxidative stress (NFKB, HMOX1, GPx) and MQ polarization markers (IL10, IL4, IL13, MRC1, MRC2 RETNLA, IL12 andIL23) were measured by qRT-PCR. The surface/mRNA expression of TLR2/TLR4 was detected by FACS and qRT-PCR.

Results

In PBEC-ALI exposure to DEP significantly increased the secretion of CXCL8, mRNA expression of inflammatory markers (CXCL8, TNFα) and oxidative stress markers (NFKB, HMOX1, GPx). However, mRNA expressions of these markers (CXCL8, IL6, NFKB, and HMOX1) were reduced in PBEC-ALI/MQ models after DEP exposure. TLR2 and TLR4 mRNA expression increased after DEP exposure in PBEC-ALI. The surface expression of TLR2 and TLR4 on PBEC was significantly reduced in sham-exposed PBEC-ALI/MQ compared to PBEC-ALI. After DEP exposure surface expression of TLR2 was increased on PBEC of PBEC-ALI/MQ, while TLR4 was decreased in both models. DEP exposure resulted in similar expression pattern of TLR2/TLR4 on MQ as in PBEC. In PBEC-ALI/MQ, DEP exposure increased the mRNA expression of anti-inflammatory M2 macrophage markers (IL10, IL4, IL13, MRC1, MRC2).

Conclusion

The cellular interaction of PBEC with MQ in response to DEP plays a pivotal role for MQ phenotypic alteration towards M2-subtypes, thereby promoting an efficient resolution of the inflammation. Furthermore, this study highlighted the fact that cell–cell interaction using multicellular ALI-models combined with an in vivo-like inhalation exposure system is critical in better mimicking the airway physiology compared with traditional cell culture systems.

Electronic supplementary material

The online version of this article (10.1186/s12989-018-0256-2) contains supplementary material, which is available to authorized users.

Human Plasma Thioredoxin-80 Increases With Age and in ApoE-/- Mice Induces Inflammation, Angiogenesis, and Atherosclerosis

BACKGROUND

Thioredoxin (TRX)-1, a ubiquitous 12-kDa protein, exerts antioxidant and anti-inflammatory effects. In contrast, the truncated form, called TRX80, produced by macrophages induces upregulation of proinflammatory cytokines. TRX80 also promotes the differentiation of mouse peritoneal and human macrophages toward a proinflammatory M1 phenotype.

METHODS

TRX1 and TRX80 plasma levels were determined with a specific ELISA. A disintegrin and metalloproteinase domain-containing protein (ADAM)-10, ADAM-17, and ADAM-10 activities were measured with SensoLyte 520 ADAM10 Activity Assay Kit, Fluorimetric, and InnoZyme TACE Activity Kit, respectively. Western immunoblots were performed with specific antibodies to ADAM-10 or ADAM-17. Angiogenesis study was evaluated in vitro with human microvascular endothelial cells-1 and in vivo with the Matrigel plug angiogenesis assay in mice. The expression of macrophage phenotype markers was investigated with real-time polymerase chain reaction. Phosphorylation of Akt, mechanistic target of rapamycin, and 70S6K was determined with specific antibodies. The effect of TRX80 on NLRP3 inflammasome activity was evaluated by measuring the level of interleukin-1β and -18 in the supernatants of activated macrophages with ELISA. Hearts were used for lesion surface evaluation and immunohistochemical studies, and whole descending aorta were stained with Oil Red O. For transgenic mice generation, the human scavenger receptor (SR-A) promoter/enhancer was used to drive macrophage-specific expression of human TRX80 in mice.

RESULTS

In this study, we observed a significant increase of plasma levels of TRX80 in old subjects compared with healthy young subjects. In parallel, an increase in expression and activity of ADAM-10 and ADAM-17 in old peripheral blood mononuclear cells compared with those of young subjects was observed. Furthermore, TRX80 was found to colocalize with tumor necrosis factor-α, a macrophage M1 marker, in human atherosclerotic plaque. In addition, TRX80 induced the expression of murine M1 macrophage markers through Akt2/mechanistic target of rapamycin-C1/70S6K pathway and activated the inflammasome NLRP3, leading to the release of interleukin-1β and -18, potent atherogenic cytokines. Moreover, TRX80 exerts a powerful angiogenic effect in both in vitro and in vivo mouse studies. Finally, transgenic mice that overexpress human TRX80 specifically in macrophages of apoE^-/- mice have a significant increase of aortic atherosclerotic lesions.

CONCLUSIONS

TRX80 showed an age-dependent increase in human plasma. In mouse models, TRX80 was associated with a proinflammatory status and increased atherosclerosis.

New development of the yolk sac theory in diabetic embryopathy: molecular mechanism and link to structural birth defects

Maternal diabetes mellitus is a significant risk factor for structural birth defects, including congenital heart defects and neural tube defects. With the rising prevalence of type 2 diabetes mellitus and obesity in women of childbearing age, diabetes mellitus-induced birth defects have become an increasingly significant public health problem. Maternal diabetes mellitus in vivo and high glucose in vitro induce yolk sac injuries by damaging the morphologic condition of cells and altering the dynamics of organelles. The yolk sac vascular system is the first system to develop during embryogenesis; therefore, it is the most sensitive to hyperglycemia. The consequences of yolk sac injuries include impairment of nutrient transportation because of vasculopathy. Although the functional relationship between yolk sac vasculopathy and structural birth defects has not yet been established, a recent study reveals that the quality of yolk sac vasculature is related inversely to embryonic malformation rates. Studies in animal models have uncovered key molecular intermediates of diabetic yolk sac vasculopathy, which include hypoxia-inducible factor-1α, apoptosis signal-regulating kinase 1, and its inhibitor thioredoxin-1, c-Jun-N-terminal kinases, nitric oxide, and nitric oxide synthase. Yolk sac vasculopathy is also associated with abnormalities in arachidonic acid and myo-inositol. Dietary supplementation with fatty acids that restore lipid levels in the yolk sac lead to a reduction in diabetes mellitus-induced malformations. Although the role of the human yolk in embryogenesis is less extensive than in rodents, nevertheless, human embryonic vasculogenesis is affected negatively by maternal diabetes mellitus. Mechanistic studies have identified potential therapeutic targets for future intervention against yolk sac vasculopathy, birth defects, and other complications associated with diabetic pregnancies.

In vivo evaluation of different alterations of redox status by studying pharmacokinetics of nitroxides using magnetic resonance techniques

Free radicals, particularly reactive oxygen species (ROS), are involved in various pathologies, injuries related to radiation, ischemia-reperfusion or ageing. Unfortunately, it is virtually impossible to directly detect free radicals in vivo, but the redox status of the whole organism or particular organ can be studied in vivo by using magnetic resonance techniques (EPR and MRI) and paramagnetic stable free radicals - nitroxides. Here we review results obtained in vivo following the pharmacokinetics of nitroxides on experimental animals (and a few in humans) under various conditions. The focus was on conditions where the redox status has been altered by induced diseases or harmful agents, clearly demonstrating that various EPR/MRI/nitroxide combinations can reliably detect metabolically induced changes in the redox status of organs. These findings can improve our understanding of oxidative stress and provide a basis for studying the effectiveness of interventions aimed to modulate oxidative stress. Also, we anticipate that the in vivo EPR/MRI approach in studying the redox status can play a vital role in the clinical management of various pathologies in the years to come providing the development of adequate equipment and probes.

Expression, characterization and crystal structure of thioredoxin from Schistosoma japonicum

Schistosoma japonicum, a human blood fluke, causes a parasitic disease affecting millions of people in Asia. Thioredoxin-glutathione system of S. japonicum plays a critical role in maintaining the redox balance in parasite, which is a potential target for development of novel antischistosomal agents. Here we cloned the gene of S. japonicum thioredoxin (SjTrx), expressed and purified the recombinant SjTrx in Escherichia coli. Functional assay shows that SjTrx catalyses the dithiothreitol (DTT) reduction of insulin disulphide bonds. The coupling assay of SjTrx with its endogenous reductase, thioredoxin glutathione reductase from S. japonicum (SjTGR), supports its biological function to maintain the redox homeostasis in the cell. Furthermore, the crystal structure of SjTrx in the oxidized state was determined at 2.0 Å resolution, revealing a typical architecture of thioredoxin fold. The structural information of SjTrx provides us important clues for understanding the maintenance function of redox homeostasis in S. japonicum and pathogenesis of this chronic disease.

Does metabolic reprogramming underpin age-associated changes in T cell phenotype and function?

T cells are required for an effective adaptive immune response. The principal function of T cells is to promote efficient removal of foreign material by identifying and mounting a specific response to nonself. A decline in T cell function in aging is thought to contribute to reduced response to infection and vaccination and an increase in autoimmunity. This may in part be due to the age-related decrease in naïve CD4(+) T cells and increase in antigen-experienced CD4(+) T cells, loss of redox homeostasis, and impaired metabolic switching. Switching between subsets is triggered by the integration of extracellular signals sensed through surface receptors and the activation of discrete intracellular metabolic pathways. This article explores how metabolic programming and loss of redox homeostasis during aging may contribute to age-associated changes in T cell phenotype and function.

The thioredoxin system as a therapeutic target in human health and disease

The thioredoxin (Trx) system comprises Trx, truncated Trx (Trx-80), Trx reductase, and NADPH, besides a natural Trx inhibitor, the thioredoxin-interacting protein (TXNIP). This system is essential for maintaining the balance of the cellular redox status, and it is involved in the regulation of redox signaling. It is also pivotal for growth promotion, neuroprotection, inflammatory modulation, antiapoptosis, immune function, and atherosclerosis. As an ubiquitous and multifunctional protein, Trx is expressed in all forms of life, executing its function through its antioxidative, protein-reducing, and signal-transducing activities. In this review, the biological properties of the Trx system are highlighted, and its implications in several human diseases are discussed, including cardiovascular diseases, heart failure, stroke, inflammation, metabolic syndrome, neurodegenerative diseases, arthritis, and cancer. The last chapter addresses the emerging therapeutic approaches targeting the Trx system in human diseases.

Selection of genes for gene-environment interaction studies: a candidate pathway-based strategy using asthma as an example

BACKGROUND

The identification of gene by environment (GxE) interactions has emerged as a challenging but essential task to fully understand the complex mechanism underlying multifactorial diseases. Until now, GxE interactions have been investigated by candidate approaches examining a small number of genes, or agnostically at the genome wide level.

PRESENTATION OF THE HYPOTHESIS

In this paper, we propose a gene selection strategy for investigation of gene-environment interactions. This strategy integrates the information on biological processes shared by genes, the canonical pathways to which they belong and the biological knowledge related to the environment in the gene selection process. It relies on both bioinformatics resources and biological expertise.

TESTING THE HYPOTHESIS

We illustrate our strategy by considering asthma, tobacco smoke as the environmental exposure, and genes sharing the same biological function of "response to oxidative stress". Our filtering strategy leads to a list of 28 pathways involving 182 genes for further GxE investigation.

IMPLICATIONS OF THE HYPOTHESIS

By integrating the environment into the gene selection process, we expect that our strategy will improve the ability to identify the joint effects and interactions of environmental and genetic factors in disease.

Redox-active protein thioredoxin-1 administration ameliorates influenza A virus (H1N1)-induced acute lung injury in mice

OBJECTIVES

Influenza virus infections can cause severe acute lung injury leading to significant morbidity and mortality. Thioredoxin-1 is a redox-active defensive protein induced in response to stress conditions. Animal experiments have revealed that thioredoxin-1 has protective effects against various severe disorders. This study was undertaken to evaluate the protective effects of recombinant human thioredoxin-1 administration on influenza A virus (H1N1)-induced acute lung injury in mice.

DESIGN

Prospective animal trial.

SETTING

Research laboratory.

SUBJECTS

Nine-week-old male C57BL/6 mice inoculated with H1N1.

INTERVENTION

The mice were divided into a vehicle-treated group and recombinant human thioredoxin-1-treated group. For survival rate analysis, the vehicle or recombinant human thioredoxin-1 was administered intraperitoneally every second day from day -1 to day 13. For lung lavage and pathological analyses, vehicle or recombinant human thioredoxin-1 was administered intraperitoneally on days -1, 1, and 3.

MEASUREMENTS AND MAIN RESULTS

Lung lavage and pathological analyses were performed at 24, 72, and 120 hrs after inoculation. The recombinant human thioredoxin-1 treatment significantly improved the survival rate of H1N1-inoculated mice, although the treatment did not affect virus propagation in the lung. The treatment significantly attenuated the histological changes and neutrophil infiltration in the lung of H1N1-inoculated mice. The treatment significantly attenuated the production of tumor necrosis factor-α and chemokine (C-X-C motif) ligand 1 in the lung and oxidative stress enhancement, which were observed in H1N1-inoculated mice. H1N1 induced expressions of tumor necrosis factor-α and chemokine (C-X-C motif) ligand 1 in murine lung epithelial cells MLE-12, which were inhibited by the addition of recombinant human thioredoxin-1. The recombinant human thioredoxin-1 treatment started 30 mins after H1N1 inoculation also significantly improved the survival of the mice.

CONCLUSIONS

Exogenous administration of recombinant human thioredoxin-1 significantly improved the survival rate and attenuated lung histological changes in the murine model of influenza pneumonia. The protective mechanism of thioredoxin-1 might be explained by its potent antioxidative and anti-inflammatory actions. Consequently, recombinant human thioredoxin-1 might be a possible pharmacological strategy for severe influenza virus infection in humans.

Different genes interact with particulate matter and tobacco smoke exposure in affecting lung function decline in the general population

BACKGROUND

Oxidative stress related genes modify the effects of ambient air pollution or tobacco smoking on lung function decline. The impact of interactions might be substantial, but previous studies mostly focused on main effects of single genes.

OBJECTIVES

We studied the interaction of both exposures with a broad set of oxidative-stress related candidate genes and pathways on lung function decline and contrasted interactions between exposures.

METHODS

For 12679 single nucleotide polymorphisms (SNPs), change in forced expiratory volume in one second (FEV(1)), FEV(1) over forced vital capacity (FEV(1)/FVC), and mean forced expiratory flow between 25 and 75% of the FVC (FEF(25-75)) was regressed on interval exposure to particulate matter <10 µm in diameter (PM10) or packyears smoked (a), additive SNP effects (b), and interaction terms between (a) and (b) in 669 adults with GWAS data. Interaction p-values for 152 genes and 14 pathways were calculated by the adaptive rank truncation product (ARTP) method, and compared between exposures. Interaction effect sizes were contrasted for the strongest SNPs of nominally significant genes (p(interaction)<0.05). Replication was attempted for SNPs with MAF>10% in 3320 SAPALDIA participants without GWAS.

RESULTS

On the SNP-level, rs2035268 in gene SNCA accelerated FEV(1)/FVC decline by 3.8% (p(interaction) = 2.5×10(-6)), and rs12190800 in PARK2 attenuated FEV1 decline by 95.1 ml p(interaction) = 9.7×10(-8)) over 11 years, while interacting with PM10. Genes and pathways nominally interacting with PM10 and packyears exposure differed substantially. Gene CRISP2 presented a significant interaction with PM10 (p(interaction) = 3.0×10(-4)) on FEV(1)/FVC decline. Pathway interactions were weak. Replications for the strongest SNPs in PARK2 and CRISP2 were not successful.

CONCLUSIONS

Consistent with a stratified response to increasing oxidative stress, different genes and pathways potentially mediate PM10 and tobacco smoke effects on lung function decline. Ignoring environmental exposures would miss these patterns, but achieving sufficient sample size and comparability across study samples is challenging.

Genetic and epigenetic influence on the response to environmental particulate matter

Ambient air pollution, including particulate matter (PM) and gaseous pollutants, represents important environmental exposures that adversely affect human health. Because of their heritable and reversible nature, epigenetic modifications provide a plausible link between the environment and alterations in gene expression that might lead to disease. Epidemiologic evidence supports that environmental exposures in childhood affect susceptibility to disease later in life, supporting the belief that epigenetic changes can affect ongoing development and promote disease long after the environmental exposure has ceased. Indeed, allergic disorders often have their roots in early childhood, and early exposure to PM has been strongly associated with the subsequent development of asthma. The purpose of this review is to summarize recent findings on the genetic and epigenetic regulation of responses to ambient air pollutants, specifically respirable PM, and their association with the development of allergic disorders. Understanding these epigenetic biomarkers and how they integrate with genetic influences to translate the biologic effect of particulate exposure is critical to developing novel preventative and therapeutic strategies for allergic disorders.

Cell stress proteins in atherothrombosis

Cell stress proteins (CSPs) are a large and heterogenous family of proteins, sharing two main characteristics: their levels and/or location are modified under stress and most of them can exert a chaperon function inside the cells. Nonetheless, they are also involved in the modulation of several mechanisms, both at the intracellular and the extracellular compartments. There are more than 100 proteins belonging to the CSPs family, among them the thioredoxin (TRX) system, which is the focus of the present paper. TRX system is composed of several proteins such as TRX and peroxiredoxin (PRDX), two thiol-containing enzymes that are key players in redox homeostasis due to their ability to scavenge potential harmful reactive oxygen species. In addition to their main role as antioxidants, recent data highlights their function in several processes such as cell signalling, immune inflammatory responses, or apoptosis, all of them key mechanisms involved in atherothrombosis. Moreover, since TRX and PRDX are present in the pathological vascular wall and can be secreted under prooxidative conditions to the circulation, several studies have addressed their role as diagnostic, prognostic, and therapeutic biomarkers of cardiovascular diseases (CVDs).

Reduction of glucose intolerance with high fat feeding is associated with anti-inflammatory effects of thioredoxin 1 overexpression in mice

Aging is associated with reduced ability to maintain normal glucose homeostasis. It has been suggested that an age-associated increase in chronic pro-inflammatory state could drive this reduction in glucoregulatory function. Thioredoxins (Trx) are oxido-reductase enzymes that play an important role in the regulation of oxidative stress and inflammation. In this study, we tested whether overexpression of Trx1 in mice [Tg(TRX1)^+/0] could protect from glucose metabolism dysfunction caused by high fat diet feeding. Body weight and fat mass gains with high fat feeding were similar in Tg(TRX1)^+/0 and wild-type mice; however, high fat diet induced glucose intolerance was reduced in Tg(TRX1)^+/0 mice relative to wild-type mice. In addition, expression of the pro-inflammatory cytokine TNF-α was reduced in adipose tissue of Tg(TRX1)^+/0 mice compared to wild-type mice. These findings suggest that activation of thioredoxins may be a potential therapeutic target for maintenance of glucose metabolism with obesity or aging.

Health and cellular impacts of air pollutants: from cytoprotection to cytotoxicity

Air pollution as one of the ravages of our modern societies is primarily linked to urban centers, industrial activities, or road traffic. These atmospheric pollutants have been incriminated in deleterious health effects by numerous epidemiological and in vitro studies. Environmental air pollutants are a heterogeneous mixture of particles suspended into a liquid and gaseous phase which trigger the disruption of redox homeostasis—known under the term of cellular oxidative stress—in relation with the establishment of inflammation and cell death via necrosis, apoptosis, or autophagy. Activation or repression of the apoptotic process as an adaptative response to xenobiotics might lead to either acute or chronic toxicity. The purpose of this paper is to highlight the central role of oxidative stress induced by air pollutants and to focus on the subsequent cellular impacts ranging from cytoprotection to cytotoxicity by decreasing or stimulating apoptosis, respectively.

Recombinant adeno-associated virus delivered human thioredoxin-PR39 prevents hypoxia-induced apoptosis of ECV304 cells

Human thioredoxin and antibacterial peptide, PR39, have been shown to have potent antioxidant effects that may prolong survival of cells during hypoxia. The pSSCMV/human thioredoxin-PR39 vector was successfully constructed in this study and used to infect ECV304 cells. Transfected ECV304 cells were incubated at 1%, 5% hypoxic, and normal oxygen conditions. We found that the number of apoptotic cells after transfection with recombinant adeno-associated virus-human thioredoxin -PR39 was significantly lower than controls, suggesting a protective effect of the recombinant human thioredoxin-PR39 protein on hypoxic cells.

Secretome of human bronchial epithelial cells in response to the fungal pathogen Aspergillus fumigatus analyzed by differential in-gel electrophoresis

BACKGROUND

For years, the analysis of innate responses to the major mold pathogen Aspergillus fumigatus has been restricted to specialized cells, such as professional phagocytes. More recently, the contribution of the airway epithelial barrier has been assessed and studies have shown that it was able to sense and react to the Aspergillus infection, for example, by producing cytokines.

METHODS

To further explore the reaction of the respiratory epithelium to the fungus, we analyzed the proteome response of a human bronchial epithelial cell line to Aspergillus infection using difference gel electrophoresis. We studied the protein pattern of BEAS-2B cell culture supernatant after interaction of the cells with Aspergillus during a 15-hour coculture.

RESULTS

We found formerly unknown aspects of bronchial cell behavior during Aspergillus infection: bronchial cells are able to develop both cellular defense mechanisms (ie, thioredoxin system activation) and immune reactions (ie, lysosomal degranulation and cathepsin activation) in response to the fungal aggression.

CONCLUSIONS

Bronchial epithelial cells appear to be a more important effector of antifungal defense than expected. Degranulation of lysosomal enzymes that might be responsible for both fungal growth inhibition and host cell damage suggests that inductors/inhibitors of these pathways may be potential targets of therapeutic intervention.

Role of thioredoxin in lung disease

Thioredoxin system is a ubiquitous thiol oxidoreductase system that regulates cellular reduction/oxidation (redox) status. It includes thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH. Trx plays an essential role in cell function by limiting oxidative stress directly via antioxidant effects and indirectly by proteins interaction with key signal transduction molecules. A variety of signaling molecules have been implicated in the cytoprotection conferred by Trx, such as autophagic proteins, p38 mitogen-activated protein kinase, nuclear factor-κB, phosphatidylinositol 3-kinase. Recent studies indicated that Trx may contribute to the pathogenesis of COPD, asthma and lung injury. Enhanced Trx expression or application of recombinant Trx afforded protection in preclinical models of pulmonary tissue injury, which suggested Trx may be used in future therapeutic applications. The focus of this review is on the significance of Trx in various pulmonary diseases, which as a potential therapeutic strategy to protect against oxidative stress and inflammation.

Urban particulate matter activates Akt in human lung cells

The normally picturesque Cache Valley in northern Utah is frequently reported to have the worst particulate (PM) air pollution in the United States. Numerous epidemiological studies conducted elsewhere have associated PM exposure to a variety of cardiovascular diseases and early mortality. We have previously shown that Cache Valley PM (CVPM) is pro-inflammatory, through a variety of mechanisms involving the release of inflammatory cytokines, unfolded protein response, ER stress, and C-reactive protein (CRP). This study was undertaken to determine whether Cache Valley PM (CVPM) would activate Akt, an upstream mechanism common to these events. Human lung (BEAS-2B) cells were treated with either fine (PM(2.5)) or coarse (PM(10)) particles (12.5 and 25 μg/ml) for periods up to 24 h. PM-exposed cells exhibited Akt activation as evidenced by phosphorylation at Thr(308) and Ser(473). Events downstream of Akt activation such as NF-κB activation were observed at 1 and 24 h, but IκB phosphorylation occurred only at 24 h, indicating that mechanisms of PM-mediated NF-κB activation are time dependent. Akt and NF-κB related inflammatory cytokine IL-1α, and IL-6 and the chemokine IL-8 were upregulated in treated cells at 6 and 24 h. The calpain inhibitor leupeptin limited Akt phosphorylation to Ser(473) and reduced release of IL-1α, IL-6, and IL-8, indicating that calpain or similar protease(s) are involved in PM-induced activation of Akt and subsequent release of inflammatory cytokines. Our data indicate that PM activates Akt, which may play a role in the pro-inflammatory response to PM exposure.

Production of biologically active human thioredoxin 1 protein in lettuce chloroplasts

The production of human therapeutic proteins in plants provides opportunities for low-cost production, and minimizes the risk of contamination from potential human pathogens. Chloroplast genetic engineering is a particularly promising strategy, because plant chloroplasts can produce large amounts of foreign target proteins. Oxidative stress is a key factor in various human diseases. Human thioredoxin 1 (hTrx1) is a stress-induced protein that functions as an antioxidant against oxidative stress, and overexpression of hTrx1 has been shown to suppress various diseases in mice. Therefore, hTrx1 is a prospective candidate as a new human therapeutic protein. We created transplastomic lettuce expressing hTrx1 under the control of the psbA promoter. Transplastomic plants grew normally and were fertile. The hTrx1 protein accumulated to approximately 1% of total soluble protein in mature leaves. The hTrx1 protein purified from lettuce leaves was functionally active, and reduced insulin disulfides. The purified protein protected mouse insulinoma line 6 cells from damage by hydrogen peroxide, as reported previously for a recombinant hTrx1 expressed in Escherichia coli. This is the first report of expression of the biologically active hTrx1 protein in plant chloroplasts. This research opens up possibilities for plant-based production of hTrx1. Considering that this expression host is an edible crop plant, this transplastomic lettuce may be suitable for oral delivery of hTrx1.

Effects of hyperoxia on cytoplasmic thioredoxin system in alveolar type epithelial cells of premature rats

This study investigated the effects of hyperoxia on dynamic changes of thioredoxin-1 (Trx1) and thioredoxin reductase-1 (TrxR1) in alveolar type II epithelial cells (AECII) of premature rats. Pregnant Sprague-Dawley rats were sacrificed on day 19 of gestation. AECII were isolated and purified from the lungs of premature rats. When cultured to 80% confluence, in vitro cells were randomly divided into air group and hyperoxia group. Cells in the hyperoxia group were continuously exposed to 95% O(2)/5% CO(2) and those in the air group to 95% air/5% CO(2). After 12, 24 and 48 h, cells in the two groups were harvested to detect their reactive oxygen species (ROS), apoptosis, TrxR1 activity and the expressions of Trx1 and TrxR1 by corresponding protocols, respectively. The results showed that AEC II exposed to hyperoxia generated excessive ROS and the apoptosis percentage in the hyperoxia group was increased significantly at each time points as compared with that in the air group (P<0.001). Moreover, TrxR1 activity was found to be markedly depressed in the hyperoxia group in comparison to that in the air group (P<0.001). RT-PCR showed the expressions of both Trx1 and TrxR1 mRNA were significantly increased in AECII exposed to hyperoxia for 12 and 24 h (P<0.01), respectively. At 48 h, the level of Trx1 mRNA as well as that of TrxR1 mRNA in the hyperoxia group was reduced and showed no significant difference from that in the air group (P>0.05). Western blotting showed the changes of Trx1 protein expressions in the hyperoxia group paralleled those of Trx1 mRNA expressions revealed by RT-PCR. It was concluded that hyperoxia can up-regulate the protective Trx1/TrxR1 expressed by AECII in a certain period, however, also cause dysfunction of the cytoplasmic thioredoxin system by decreasing TrxR1 activity, which may contribute to the progression of oxidative stress and cell apoptosis and finally result in lung injury.

Anti-inflammatory effects of limonene from yuzu (Citrus junos Tanaka) essential oil on eosinophils

Yuzu (Citrus junos Tanaka) has been used as a traditional medicine in Japan. We investigated in vitro anti-inflammatory effects of limonene from yuzu peel on human eosinophilic leukemia HL-60 clone 15 cells. To examine anti-inflammatory effects of limonene on the cells, we measured the level of reactive oxygen species (ROS), monocyte chemoattractant protein-1 (MCP-1), nuclear factor (NF) kappa B, and p38 mitogen-activated protein kinase (MAPK). We found that low concentration of limonene (7.34 mmol/L) inhibited the production of ROS for eotaxin-stimulated HL-60 clone 15 cells. 14.68 mmol/L concentration of limonene diminished MCP-1 production via NF-kappa B activation comparable to the addition of the proteasomal inhibitor MG132. In addition, it inhibited cell chemotaxis in a p38 MAPK dependent manner similar to the adding of SB203580. These results suggest that limonene may have potential anti-inflammatory efficacy for the treatment of bronchial asthma by inhibiting cytokines, ROS production, and inactivating eosinophil migration.

Role of oxidative damage in toxicity of particulates

Particulates are small particles of solid or liquid suspended in liquid or air. In vitro studies show that particles generate reactive oxygen species, deplete endogenous antioxidants, alter mitochondrial function and produce oxidative damage to lipids and DNA. Surface area, reactivity and chemical composition play important roles in the oxidative potential of particulates. Studies in animal models indicate that particles from combustion processes (generated by combustion of wood or diesel oil), silicate, titanium dioxide and nanoparticles (C60 fullerenes and carbon nanotubes) produce elevated levels of lipid peroxidation products and oxidatively damaged DNA. Biomonitoring studies in humans have shown associations between exposure to air pollution and wood smoke particulates and oxidative damage to DNA, deoxynucleotides and lipids measured in leukocytes, plasma, urine and/or exhaled breath. The results indicate that oxidative stress and elevated levels of oxidatively altered biomolecules are important intermediate endpoints that may be useful markers in hazard characterization of particulates.

Redox regulation of cell survival by the thioredoxin superfamily: an implication of redox gene therapy in the heart

Reactive oxygen species (ROS) are the key mediators of pathogenesis in cardiovascular diseases. Members of the thioredoxin superfamily take an active part in scavenging reactive oxygen species, thus playing an essential role in maintaining the intracellular redox status. The alteration in the expression levels of thioredoxin family members and related molecules constitute effective biomarkers in various diseases, including cardiovascular complications that involve oxidative stress. Thioredoxin, glutaredoxin, peroxiredoxin, and glutathione peroxidase, along with their isoforms, are involved in interaction with the members of metabolic and signaling pathways, thus making them attractive targets for clinical intervention. Studies with cells and transgenic animals have supported this notion and raised the hope for possible gene therapy as modern genetic medicine. Of all the molecules, thioredoxins, glutaredoxins, and peroxiredoxins are emphasized, because a growing body of evidence reveals their essential and regulatory role in several steps of redox regulation. In this review, we discuss some pertinent observations regarding their distribution, structure, functions, and interactions with the several survival- and death-signaling pathways, especially in the myocardium.

Thioredoxin-binding protein-2 deficiency enhances methionine-choline deficient diet-induced hepatic steatosis but inhibits steatohepatitis in mice

In nonalcoholic fatty liver disease, oxidative stress is believed to play a crucial role as a second-hit for the progression of simple steatosis to steatohepatitis. Thioredoxin (TRX) is a potent antioxidant molecule that exerts anti-apoptotic and anti-inflammatory functions. TRX-binding protein-2 (TBP-2) is an endogenous negative regulator of TRX. Deficiency of TBP-2 in mice causes hyperlipidemia, hepatic steatosis, hypoglycemia, and bleeding tendency, resembling Reye syndrome in a fasting/glucose-deficient state. The aim of this study was to investigate the role of TBP-2 in the development of nonalcoholic steatohepatitis (NASH). TBP-2-deficient (TBP-2(-/-)) and wild-type (WT) mice were fed either a normal or methionine-choline-deficient (MCD) diet for up to 10 weeks. Compared with WT mice, TBP-2(-/-) mice showed severe simple steatosis rather than steatohepatitis. However, oxidative stress determined by lipid peroxidation and DNA damage, neutrophil infiltration, and hepatic fibrosis were attenuated in TBP-2(-/-) mice. PCR analysis showed the expressions of fibrosis-inducing and inflammatory cytokine-related genes were less in TBP-2(-/-) mice. Moreover, leptin, SREBP1c, PPARgamma, and adipogenesis-lipogenesis-related genes were upregulated in TBP-2(-/-) mice. These results strongly suggested that TBP-2 might be involved in pathogenesis of NASH in WT mice, and inhibitors of TBP-2 could be useful in the prevention or treatment of NASH.

Thioredoxin 1 delivery as new therapeutics

Thioredoxin 1 (Trx 1) is a redox-active small protein ubiquitously present in human body. It is one of the defensive proteins induced in response to various stress conditions. In addition to its anti-oxidative effect by dithiol-disulfide exchange in its active site, Trx 1 has anti-apoptotic and anti-inflammatory effects. Trx 1 overexpression has been shown to be effective in a wide variety of animal models for oxidative and inflammatory disorders. An administration of recombinant Trx 1 protein is also effective in animal models especially for severe acute lung diseases where Trx 1 is likely to act with its anti-inflammatory properties. Trx 1 in circulation shows anti-chemotactic effects for neutrophils and inhibitory effects against macrophage migration inhibitory factor (MIF). Neovascularization is also suppressed by Trx 1 via inhibition of the complement activation. Here we discuss precise mechanisms of Trx 1 and potential therapeutic approach of this molecule.

Thioredoxin mediates remodeling factors of human bronchial epithelial cells upon interaction with house dust mite-stimulated eosinophils

Bronchial epithelial cells exposed to allergens typically secrete chemokines to recruit eosinophils. Persistent inflammation and repair responses result in airway remodeling and irreversible airflow limitation. House dust mite (HDM) is a common allergen causing allergic disorders. Thioredoxin (TRX) is a redox protein that scavenges reactive oxygen species (ROS). This study was to elucidate how TRX mediates gene expression of remodeling factors of human bronchial epithelial cells in response to HDM stimuli interacting with eosinophils. This study cultured normal human bronchial epithelial (BEAS-2B) cells with eosinophils exposed to 0.5 microg/ml recombinant Dermatophagoides pteronyssinus 1 (rDer p1) protease to mimic the allergen-immune reaction. Eosinophils were induced by rDer p1 protease to secrete tumor necrosis factor (TNF)-alpha and generate ROS. When cultured with rDer p1-stimulated eosinophils, BEAS-2B cells released interleukin-6 and underwent apoptosis. The HDM-stimulated eosinophils applied oxidative stress and apoptosis to BEAS-2B cells through the release of mediators. Damaged BEAS-2B cells interfered with gene expression of remodeling factors, such as transforming growth factor (TGF)-beta 1, epidermal growth factor receptor (EGFR), cyclin dependent kinase inhibitor (p21(waf)) and matrix metalloproteinase (MMP) 9, relevant to inflammatory response and epithelial repair in airway remodeling. Notably, BEAS-2B cells over-expressing TRX reduced eosinophil-derived apoptosis and suppressed underlying airway remodeling via attenuation of TGF-beta1, EGFR and p21(waf) and up-regulation of MMP9 expression. Results of this study indicated TRX-over-expressing bronchial epithelial cells attenuated TGF-beta1 and activated MMP9 expression to prevent airway remodeling from HDM-induced inflammation. The finding can be as a reference for further therapeutic studies of TRX.

Genetic variation and gene expression in antioxidant related enzymes and risk of COPD: a systematic review

BACKGROUND

Observational epidemiological studies of dietary antioxidant intake, serum antioxidant concentration and lung outcomes suggest that lower levels of antioxidant defences are associated with decreased lung function. Another approach to understanding the role of oxidant/antioxidant imbalance in the risk of chronic obstructive pulmonary disease (COPD) is to investigate the role of genetic variation in antioxidant enzymes, and indeed family based studies suggest a heritable component to lung disease. Many studies of the genes encoding antioxidant enzymes have considered COPD or COPD related outcomes, and a systematic review is needed to summarise the evidence to date, and to provide insights for further research.

METHODS

Genetic association studies of antioxidant enzymes and COPD/COPD related traits, and comparative gene expression studies with disease or smoking as the exposure were systematically identified and reviewed. Antioxidant enzymes considered included enzymes involved in glutathione metabolism, in the thioredoxin system, superoxide dismutases (SOD) and catalase.

RESULTS

A total of 29 genetic association and 15 comparative gene expression studies met the inclusion criteria. The strongest and most consistent effects were in the genes GCL, GSTM1, GSTP1 and SOD3. This review also highlights the lack of studies for genes of interest, particularly GSR, GGT and those related to TXN. There were limited opportunities to evaluate the contribution of a gene to disease risk through synthesis of results from different study designs, as the majority of studies considered either association of sequence variants with disease or effect of disease on gene expression.

CONCLUSION

Network driven approaches that consider potential interaction between and among genes, smoke exposure and antioxidant intake are needed to fully characterise the role of oxidant/antioxidant balance in pathogenesis.

Redox-regulated mechanisms in asthma

Homeostasis of the reduction-oxidation (redox) state is critical to protection from oxidative stress in the lungs. Therefore, the lungs have high levels of antioxidants, including glutathione, heme oxygenase, and superoxide dismutase. The numbers of inflammatory cells -- particularly eosinophils -- are increased in the airways of asthma patients, and these pulmonary inflammatory cells release large amounts of harmful reactive oxygen species and reactive nitrogen species. Human thioredoxin 1 (TRX1) is a redox-active protein of approximately 12 kDa that contains a (32)Cys-Gly-Pro-(35)Cys sequence necessary for its activity. The strong reducing activity of the sequence results from the cysteine residues acting as proton donors and cleaving disulfide (S-S) bonds in the target protein. Endogenous or exogenous TRX1 or both protect the lungs against ischemia-reperfusion injury, influenza infection, bleomycin-induced injury, or lethal pulmonary inflammation caused by interleukin-2 and interleukin-18. We showed that exogenous TRX1 inhibits airway hyperresponsiveness and pulmonary inflammation accompanied by eosinophilia in mouse models of asthma. Recently, we reported that exogenous TRX1 improves established airway remodeling in a prolonged antigen-exposure mouse asthma model. Exogenous and endogenous TRX1 also prevents the development of airway remodeling. Here, we discuss the role and clinical benefits of TRX1 in asthma.

Thioredoxin overexpression modulates remodeling factors in stress responses to cigarette smoke

Cigarette smoke (CS) generates reactive oxygen species (ROS) to produce oxidative damage of bronchial epithelial cells. Prolonged repair responses lead to airway remodeling and irreversible airflow limitation. Thioredoxin (TRX) is a redox protein that scavenges ROS to prevent oxidative stress. The aim of this study was to investigate the mechanisms underlying TRX-mediated CS-induced stress relevant to airway remodeling. Results showed that CS stimulated ROS generation and apoptosis in normal human bronchial epithelial (BEAS-2B) cells, and interfered with gene expression of remodeling factors, such as activation of transforming growth factor (TGF)-beta1, epidermal growth factor receptor (EGFR), and cyclin-dependent kinase inhibitor (p21), but repressed matrix metalloproteinases (MMP)-9. In particular, TRX-overexpressing bronchial epithelial (TRX-TD) cells reduced CS-induced apoptosis, and suppressed airway remodeling through attenuation of TGF-beta1, EGFR, and p21 and upregulation of MMP-9 expression. TGF-beta1 was shown to regulate MMP-9 as evidenced by suppression of MMP-9 protein induction by TGF-beta1 antibody. In addition, CS produced apoptosis of BEAS-2B cells via TRX oxidation, which activated signal transduction factors, including apoptosis signal-regulating kinase (ASK) 1 and c-Jun N-terminal kinase (JNK). In contrast, TRX-TD cells exposed to CS retained reduced-form TRX, and inactivated ASK1 and JNK to attenuate apoptosis. This study indicated TRX overexpression was involved in CS-induced apoptosis and prevented airway remodeling through ASK1-JNK inactivation and MMP-9 augmentation.

Thioredoxin-1 protects against hyperoxia-induced apoptosis in cells of the alveolar walls

BACKGROUND

The mechanisms of hyperoxia-induced lung injury remain poorly defined. Thioredoxin-1 (TRX-1) is a small ubiquitous protein that acts as an important radical scavenger. We investigated the effect of TRX-1 on apoptosis in hyperoxia-induced lung injury.

METHODS

Mice were exposed to 98% O(2) to produce a model of hyperoxia-induced lung injury. Using transgenic mice overexpressing human TRX-1 (hTRX-1), we assessed lung structure (n=4 per group), immunohistochemical staining for 8-hydroxy-deoxyguanosine (n=4 per group), TUNEL staining (n=5 per group), cytokine (n=5 per group) of IL-1beta and IL-6, and protein (n=6 per group) and m-RNA levels (n=4 per group) (or both) of cytochrome c, Bcl-2, Bax, p21, and p53 in the lungs.

RESULTS

After exposure to hyperoxia, hTRX-1 transgenic mice had significantly decreased alveolar damage. The apoptotic index was significantly lower in hTRX-1 transgenic mice than in wild-type (WT) mice after exposure to hyperoxia. Protein expression of cytochrome c in the lung was significantly lower in hTRX-1 transgenic mice than in WT mice after exposure to hyperoxia. Protein expression and m-RNA levels of Bcl-2 in the lung were significantly higher in hTRX-1 transgenic mice than in WT mice after exposure to hyperoxia. TRX-1 had no effect on the protein and m-RNA levels of Bax and p21. The protein and m-RNA levels of p53 was unaffected by hyperoxia in hTRX-1 transgenic mice. The cytokine level of IL-6 was significantly higher in hTRX-1 transgenic mice than in WT mice after exposure to hyperoxia. TRX-1 had no effect on cytokine level of IL-1beta.

CONCLUSIONS

These findings suggest that overexpression of hTRX-1 protects against hyperoxia-induced apoptosis in cells of the alveolar walls. The up-regulating Bcl-2 protein is considered to be one of antiapoptotic effects of TRX-1 in hyperoxia-induced lung injury.

Antioxidant enzyme induction: a new protective approach against the adverse effects of diesel exhaust particles

Exposure to airborne particulate pollutants such as diesel exhaust particles (DEPs) has been associated with allergic respiratory disorders, including asthma and allergic rhinitis. In this communication, we review recent advances in the mechanism by which DEPs elicit their harmful effects and the protective role of antioxidants. Reactive oxidative species (ROS) are believed to play a key role in cellular damage after exposure to DEPs. Numerous reports demonstrate that both proinflammatory and anti-inflammatory products are induced by DEPs via the activation of transcription factors. DEPs trigger multiple signaling pathways, which lead to DNA damage and cell apoptosis, inflammatory response, and antioxidant defense. Recent studies both in vitro and in mice show that antioxidants could alleviate the allergic inflammatory effects of DEPs. Human in vivo models suggest that the important phase II enzymes GSTM1 and GSTP1 modify the adjuvant effect of diesel exhaust particles on allergic inflammation. We have shown that the induction of phase II enzymes by the chemical sulforaphane can block DEP-induced enhanced immunoglobulin (Ig) E production in B cells and DEP-induced proinflammatory cytokine production in epithelial cells. These findings suggest that overexpression of antioxidant enzymes could constitute a powerful potential chemopreventive approach against adverse effects induced by oxidant pollutants such as DEPs.

Activation of 5-lipoxygenase and NF-kappa B in the action of acenaphthenequinone by modulation of oxidative stress

Quinoid polycyclic aromatic hydrocarbons are potent redox-active compounds that undergo enzymatic and nonenzymatic redox cycling with their semiquinone radical. We previously reported that acenaphthenequinone (AcQ) can damage human lung epithelial A549 cells through the formation of reactive species (RS). However, the biochemical mechanisms by which RS-generating enzymes cause oxidative burst during AcQ exposure remain elusive. Here we examined the biochemical mechanism of AcQ-induced RS generation by using selective metabolic inhibitors in A549 cells. We found that AA861, a 5-lipoxygenase (5-LO)-specific inhibitor significantly decreases RS generation. This inhibition of RS seems to be 5-LO specific because other inhibitors did not suppress AcQ-induced RS generation by nicotinamide adenine nucleotide phosphate (reduced) oxidase and/or xanthine oxidase. In addition, the inhibition of 5-LO by AA861 markedly reduced AcQ-induced nuclear factor kappa B (NF-kappa B) activation. We further found the activation of 5-LO pathway by exposing cells to AcQ mediates the secretion of inflammatory leukotriene B4, which can be significantly suppressed by a potent RS scavenger, N-acetylcysteine. Thus, based on our findings, we propose that AcQ-induced damage is likely due to increased RS generation and NF-kappa B activity through 5-LO activation.

Thioredoxin-1 attenuates indomethacin-induced gastric mucosal injury in mice

Indomethacin is one of non-steroidal anti-inflammatory drugs that are commonly used clinically and often cause gastric mucosal injury as a side effect. Generation of reactive oxygen species (ROS) and activation of apoptotic signaling are involved in the pathogenesis of indomethacin-induced gastric mucosal injury. Thioredoxin-1 (Trx-1) is a small redox-active protein with anti-oxidative activity and redox-regulating functions. The aim of this study was to investigate the protective effect of Trx-1 against indomethacin-induced gastric mucosal injury. Trx-1 transgenic mice displayed less gastric mucosal damage than wild type (WT) C57BL/6 mice after intraperitoneal administration of indomethacin. Administration of recombinant human Trx-1 (rhTrx-1) or transfection of the Trx-1 gene reduced indomethacin-induced cytotoxicity in rat gastric epithelial RGM-1 cells. Pretreatment with rhTrx-1 suppressed indomethacininduced ROS production and downregulation of phosphorylated Akt in RGM-1 cells. Survivin, a member of inhibitors of apoptosis proteins family, was downregulated by indomethacin, which was suppressed in Trx-1 transgenic mice or by administration of rhTrx-1 in RGM-1 cells. Trx-1 inhibits indomethacin-induced apoptotic signaling and gastric ulcer formation, suggesting that it may have a preventive and therapeutic potential against indomethacin-induced gastric injury.

Thioredoxin-related mechanisms in hyperoxic lung injury in mice

Reduction of glutathione disulfide (GSSG) to glutathione (GSH) by glutathione reductase (GR) enhances the efficiency of GSH-dependent antioxidant activities. However, GR-deficient (a1Neu) mice are less susceptible to acute lung injury from continuous exposure to > 95% O(2) (96 h: 6.9 +/- 0.1 g right lung/kg body versus room air 3.6 +/- 0.3) than are C3H/HeN control mice (10.6 +/- 1.3 versus 4.2 +/- 0.3, P < 0.001). a1Neu mice have greater hepatic thioredoxin (Trx)1 and Trx2 levels than do C3H/HeN mice, suggesting compensation for the absence of GR. a1Neu mice exposed to hyperoxia for 96 hours showed lower levels of inflammatory infiltrates in lungs than did similarly exposed C3H/HeN mice. Pretreatment with aurothioglucose (ATG), a thioredoxin reductase (TrxR) inhibitor, exacerbated the effects of hyperoxia on lung injury in a1Neu mice (11.6 +/- 0.8, P < 0.001), but attenuated hyperoxic lung edema and inflammation in C3H/HeN mice (6.3 +/- 0.4, P < 0.001). No consistent alterations were observed in lung GSH contents or liver GSH or GSSG levels after ATG pretreatment. The data suggest that modulation of Trx/TrxR systems might provide therapeutically useful alterations of cellular resistance to oxidant stresses. The protective effects of ATG against hyperoxic lung injury could prove to be particularly useful therapeutically.

Thioredoxin and thioredoxin-binding protein-2 in cancer and metabolic syndrome

Thioredoxin (TRX), a small redox-active multifunctional protein, acts as a potent antioxidant and a redox regulator in signal transduction. TRX expression is elevated in various types of human cancer. Overexpression of TRX introduces resistance to anti-cancer drugs or radiation-induced apoptosis; however, there is no evidence that the incidence of cancer is frequent in TRX-transgenic mice or that the administration of recombinant human TRX enhances tumor growth. Plasma/serum level of TRX is a good marker for oxidative stress-induced various disorders, including metabolic syndrome. Thioredoxin-binding protein-2 (TBP-2), which was originally identified as a negative regulator of TRX, acts as a growth suppressor and a regulator in lipid metabolism. TBP-2 expression is downregulated in various types of human cancer. TBP-2 deficiency induces lipid dysfunction and a phenotype resembling Reye syndrome. Thus, TRX and TBP-2 play important roles in the pathophysiology of cancer and metabolic syndrome by direct interaction or by independent mechanisms.

Neurotropin demonstrates cytoprotective effects in lung cells through the induction of thioredoxin-1

Neurotropin, a nonprotein extract from inflamed rabbit skin inoculated with vaccinia virus, is well known as an analgesic drug, but its cytoprotective effects have not been explored. Because infection by viruses, such as human T-cell leukemia virus type I and Epstein-Barr virus, induces expression of the redox-regulating molecule, thioredoxin (TRX), we hypothesized that neurotropin would also be capable of regulating the redox balance and could be applied for the therapeutics of lung diseases caused by oxidative stress, such as chronic obstructive pulmonary disease. Neurotropin enhanced mRNA expression of the redox-regulating molecules, glutathione peroxidase and catalase and, particularly, TRX, in human lung adenocarcinoma A549 cells. Neurotropin also increased the cellular TRX content and regulated TRX release from cells. The cytoprotective effects of neurotropin against hydrogen peroxide and cigarette smoke extracts was demonstrated by an attenuation of lactate dehydrogenase release from oxidant-exposed A549 cells and the inhibition of apoptosis. This cytoprotection was linked with reduced activity of intracellular oxidants. Furthermore, neurotropin enhanced TRX expression in mouse lungs and ameliorated cigarette smoke-induced lung injury in mice, suggesting that its cytoprotective effects in lung epithelial cells are mediated through the induction of redox-regulating molecules that reduce intracellular oxidative activity.

From oxygen sensing to heart failure: role of thioredoxin

Oxidative stress has been widely recognized to be involved in the pathogenesis of cardiopulmonary disorders. In ischemic heart diseases, it is involved not only in the development of atherosclerosis but also in ongoing ischemic injury, especially in the reperfusion process. Cardiomyopathy is another cardiac disorder in which oxidative stress is involved. In diabetic cardiomyopathy, homocysteine, a well-known source of oxidative stress, is believed to play major roles in its development. Thioredoxin (TRX) is a redox-acting protein ubiquitously present in the human body. It also is inducible by a wide variety of oxidative stresses. TRX is a multifunctional protein and has anti-inflammatory and antiapoptotic effects, as well as antioxidative effects. It is therefore feasible to think that TRX is a potential therapy for cardiac disease. Moreover, serum TRX is a well-recognized biomarker of various diseases involving oxidative stress, and this is also the case for cardiac disorders. Here we discuss how TRX is useful as a biomarker of and therapeutic agent for cardiopulmonary disorders, especially focusing on ischemic heart disease, myocarditis and oxygen sensing, and acute respiratory distress syndrome.

Elevation of serum thioredoxin in patients with gefitinib-induced interstitial lung disease

OBJECTIVE

Interstitial lung disease (ILD) is a severe adverse event of gefitinib therapy. However, the mechanism still remains unclear. The objective of this study was to examine whether or not oxidative stress, one of the common factors in drug-associated ILD, is involved in the pathogenesis of gefitinib-induced ILD.

PATIENTS AND METHODS

Using an enzyme-linked immunosorbent assay (ELISA), we measured the concentration of serum thioredoxin (Trx), a redox-active protein with antioxidative effects, in 44 patients treated with gefitinib, including three patients who had ILD.

RESULTS

In patients who had gefitinib-induced ILD, serum Trx levels were significantly elevated. They decreased after cessation of gefitinib therapy accompanying clinical improvement of ILD.

CONCLUSION

It was suggested that oxidative stress may be involved as a part of mechanisms causing or worsening gefitinib-induced ILD.