Yvonne Janssen-heininger - Academia.edu (original) (raw)

Papers by Yvonne Janssen-heininger

American Journal of Physiology-Lung Cellular and Molecular Physiology

Obesity is associated with severe, difficult-to-control asthma, and increased airway oxidative st... more Obesity is associated with severe, difficult-to-control asthma, and increased airway oxidative stress. Mitochondrial reactive oxygen species (mROS) are an important source of oxidative stress in asthma, leading us to hypothesize that targeting mROS in obese allergic asthma might be an effective treatment. Using a mouse model of house dust mite (HDM)-induced allergic airway disease in mice fed a low- (LFD) or high-fat diet (HFD), and the mitochondrial antioxidant MitoQuinone (MitoQ), we investigated the effects of obesity and ROS on HDM-induced airway inflammation, remodeling, and airway hyperresponsiveness (AHR). Obese allergic mice showed increased lung tissue eotaxin, airway tissue eosinophilia, and AHR compared with lean allergic mice. MitoQ reduced airway inflammation, remodeling, and hyperreactivity in both lean and obese allergic mice, and tissue eosinophilia in obese-allergic mice. Similar effects were observed with decyl triphosphonium (dTPP+), the hydrophobic cationic moiet...

Antioxidants

Glutathione (GSH), a major antioxidant in mammalian cells, regulates several vital cellular proce... more Glutathione (GSH), a major antioxidant in mammalian cells, regulates several vital cellular processes, such as nutrient metabolism, protein synthesis, and immune responses. In addition to its role in antioxidant defense, GSH controls biological processes through its conjugation to reactive protein cysteines in a post-translational modification known as protein S-glutathionylation (PSSG). PSSG has recently been implicated in the pathogenesis of multiple diseases including idiopathic pulmonary fibrosis (IPF). Hallmarks of IPF include repeated injury to the alveolar epithelium with aberrant tissue repair, epithelial cell apoptosis and fibroblast resistance to apoptosis, and the accumulation of extracellular matrix and distortion of normal lung architecture. Several studies have linked oxidative stress and PSSG to the development and progression of IPF. Additionally, it has been suggested that the loss of epithelial cell homeostasis and increased apoptosis, accompanied by the release of...

Redox Biology, 2021

Background: Interleukin-1-dependent increases in glycolysis promote allergic airways disease in m... more Background: Interleukin-1-dependent increases in glycolysis promote allergic airways disease in mice and disruption of pyruvate kinase M2 (PKM2) activity is critical herein. Glutathione-S-transferase P (GSTP) has been implicated in asthma pathogenesis and regulates the oxidation state of proteins via S-glutathionylation. We addressed whether GSTP-dependent S-glutathionylation promotes allergic airways disease by promoting glycolytic reprogramming and whether it involves the disruption of PKM2. Methods: We used house dust mite (HDM) or interleukin-1β in C57BL6/NJ WT or mice that lack GSTP. Airway basal cells were stimulated with interleukin-1β and the selective GSTP inhibitor, TLK199. GSTP and PKM2 were evaluated in sputum samples of asthmatics and healthy controls and incorporated analysis of the U-BIOPRED severe asthma cohort database. Results: Ablation of Gstp decreased total S-glutathionylation and attenuated HDM-induced allergic airways disease and interleukin-1β-mediated inflammation. Gstp deletion or inhibition by TLK199 decreased the interleukin-1β-stimulated secretion of pro-inflammatory mediators and lactate by epithelial cells. 13 C-glucose metabolomics showed decreased glycolysis flux at the pyruvate kinase step in response to TLK199. GSTP and PKM2 levels were increased in BAL of HDM-exposed mice as well as in sputum of asthmatics compared to controls. Sputum proteomics and transcriptomics revealed strong correlations between GSTP, PKM2, and the glycolysis pathway in asthma. Conclusions: GSTP contributes to the pathogenesis of allergic airways disease in association with enhanced glycolysis and oxidative disruption of PKM2. Our findings also suggest a PKM2-GSTP-glycolysis signature in asthma that is associated with severe disease.

Redox Biology, 2021

Our lungs are exposed daily to airborne pollutants, particulate matter, pathogens as well as lung... more Our lungs are exposed daily to airborne pollutants, particulate matter, pathogens as well as lung allergens and irritants. Exposure to these substances can lead to inflammatory responses and may induce endogenous oxidant production, which can cause chronic inflammation, tissue damage and remodeling. Notably, the development of asthma and Chronic Obstructive Pulmonary Disease (COPD) is linked to the aforementioned irritants. Some inhaled foreign chemical compounds are rapidly absorbed and processed by phase I and II enzyme systems critical in the detoxification of xenobiotics including the glutathione-conjugating enzymes Glutathione S-transferases (GSTs). GSTs, and in particular genetic variants of GSTs that alter their activities, have been found to be implicated in the susceptibility to and progression of these lung diseases. Beyond their roles in phase II metabolism, evidence suggests that GSTs are also important mediators of normal lung growth. Therefore, the contribution of GSTs to the development of lung diseases in adults may already start in utero, and continues through infancy, childhood, and adult life. GSTs are also known to scavenge oxidants and affect signaling pathways by protein-protein interaction. Moreover, GSTs regulate reversible oxidative post-translational modifications of proteins, known as protein S-glutathionylation. Therefore, GSTs display an array of functions that impact the pathogenesis of asthma and COPD. In this review we will provide an overview of the specific functions of each class of mammalian cytosolic GSTs. This is followed by a comprehensive analysis of their expression profiles in the lung in healthy subjects, as well as alterations that have been described in (epithelial cells of) asthmatics and COPD patients. Particular emphasis is placed on the emerging evidence of the regulatory properties of GSTs beyond detoxification and their contribution to (un)healthy lungs throughout life. By providing a more thorough understanding, tailored therapeutic strategies can be designed to affect specific functions of particular GSTs.

Free Radical Biology and Medicine, 2018

all enhanced in metabolically stressed BMDMs but prevented in Grx1overexpressing BMDMs. The dimer... more all enhanced in metabolically stressed BMDMs but prevented in Grx1overexpressing BMDMs. The dimer/tetramer ratio was increased in response to metabolic stress as was HIF1a-dependent expression of GLUT1 and IL-1b. Compared to monocytes isolated from HFD-fed mice, monocyte from Grx1 Mac tg mice showed reduced priming, reduced expression of PKM2, GLUT1 and IL-1b and diminished PKM2 phosphorylation. Conclusion: Metabolic stress-induced PKM2 S-glutathionylation promotes PKM2 tetramer dissociation, phosphorylation and subsequent nuclear translocation, which, via HIF1a-dependent expression of glycolytic enzymes and inflammatory cytokines, reprograms monocyte-derived macrophages into a hyper-inflammatory phenotype. This mechanism may contribute to chronic inflammatory diseases associated with metabolic disorders.

Nature medicine, Jan 9, 2018

Idiopathic pulmonary fibrosis is characterized by excessive deposition of collagen in the lung, l... more Idiopathic pulmonary fibrosis is characterized by excessive deposition of collagen in the lung, leading to chronically impaired gas exchange and death. Oxidative stress is believed to be critical in this disease pathogenesis, although the exact mechanisms remain enigmatic. Protein S-glutathionylation (PSSG) is a post-translational modification of proteins that can be reversed by glutaredoxin-1 (GLRX). It remains unknown whether GLRX and PSSG play a role in lung fibrosis. Here, we explored the impact of GLRX and PSSG status on the pathogenesis of pulmonary fibrosis, using lung tissues from subjects with idiopathic pulmonary fibrosis, transgenic mouse models and direct administration of recombinant Glrx to airways of mice with existing fibrosis. We demonstrate that GLRX enzymatic activity was strongly decreased in fibrotic lungs, in accordance with increases in PSSG. Mice lacking Glrx were far more susceptible to bleomycin- or adenovirus encoding active transforming growth factor beta...

Annals of the American Thoracic Society, 2016

S-glutathionylation has emerged as an oxidant-induced post-translational modification of protein ... more S-glutathionylation has emerged as an oxidant-induced post-translational modification of protein cysteines that affects structure and function. The oxidoreductase glutaredoxin-1 (Glrx1), under physiological conditions, catalyzes deglutathionylation and restores the protein thiol group. The involvement of Grx1/S-glutathionylation in allergic inflammation induced by asthma-relevant allergens remains unknown. In the present study we examined the impact of genetic ablation of Glrx1 for the pathogenesis of house dust mite (HDM)-induced allergic airway disease in mice. Wild-type (WT) or Glrx1(-/-) mice in the BALB/c background were instilled intranasally with 50 μg of HDM 5 consecutive days for 3 weeks and killed 72 hours post final exposure. As expected, overall protein S-glutathionylation was increased in Glrx1(-/-) mice exposed to HDM as compared with WT animals. Total cells in the bronchoalveolar lavage fluid were similarly increased in WT and Glrx1(-/-) HDM-treated mice compared with...

Free Radical Biology and Medicine, 2015

Journal of cellular biochemistry, Jan 7, 2015

Asthma is a pulmonary disorder, with an estimated 300 million people affected worldwide. While it... more Asthma is a pulmonary disorder, with an estimated 300 million people affected worldwide. While it is thought that endogenous reactive oxygen species (ROS) and reactive nitrogen species (RNS) such as hydrogen peroxide and nitric oxide, are important mediators of natural physiological processes, inflammatory cells recruited to the asthmatic airways have an exceptional capacity for producing a variety of highly reactive ROS and RNS believed to contribute to tissue damage and chronic airways inflammation. Antioxidant defense systems form a tightly regulated network that maintains the redox environment of the intra- as well as extracellular environment. Evidence for an oxidant-antioxidant imbalance in asthmatic airways is demonstrated in a number of studies, revealing decreased total antioxidant capacity as well as lower levels of individual antioxidants. Thiols in the form of GSH and sulfhydryl groups of proteins are among the most susceptible oxidant-sensitive targets, and hence, studi...

Journal of Cell Biology, 2009

Reactive oxygen species (ROS) increase ligation of Fas (CD95), a receptor important for regulatio... more Reactive oxygen species (ROS) increase ligation of Fas (CD95), a receptor important for regulation of programmed cell death. Glutathionylation of reactive cysteines represents an oxidative modification that can be reversed by glutaredoxins (Grxs). The goal of this study was to determine whether Fas is redox regulated under physiological conditions. In this study, we demonstrate that stimulation with Fas ligand (FasL) induces S-glutathionylation of Fas at cysteine 294 independently of nicotinamide adenine dinucleotide phosphate reduced oxidase–induced ROS. Instead, Fas is S-glutathionylated after caspase-dependent degradation of Grx1, increasing subsequent caspase activation and apoptosis. Conversely, overexpression of Grx1 attenuates S-glutathionylation of Fas and partially protects against FasL-induced apoptosis. Redox-mediated Fas modification promotes its aggregation and recruitment into lipid rafts and enhances binding of FasL. As a result, death-inducing signaling complex forma...

The Journal of Immunology, 2007

Oxidative stress is a hallmark of asthma, and increased levels of oxidants are considered markers... more Oxidative stress is a hallmark of asthma, and increased levels of oxidants are considered markers of the inflammatory process. Most studies to date addressing the role of oxidants in the etiology of asthma were based on the therapeutic administration of low m.w. antioxidants or antioxidant mimetic compounds. To directly address the function of endogenous hydrogen peroxide in the pathophysiology of allergic airway disease, we comparatively evaluated mice systemically overexpressing catalase, a major antioxidant enzyme that detoxifies hydrogen peroxide, and C57BL/6 strain matched controls in the OVA model of allergic airways disease. Catalase transgenic mice had 8-fold increases in catalase activity in lung tissue, and had lowered DCF oxidation in tracheal epithelial cells, compared with C57BL/6 controls. Despite these differences, both strains showed similar increases in OVA-specific IgE, IgG1, and IgG2a levels, comparable airway and tissue inflammation, and identical increases in pr...

The Journal of Immunology, 2008

Pulmonary inflammation in asthma is orchestrated by the activity of NF-B. NO and NO synthase (NOS... more Pulmonary inflammation in asthma is orchestrated by the activity of NF-B. NO and NO synthase (NOS) activity are important modulators of inflammation. The availability of the NOS substrate, L-arginine, is one of the mechanisms that controls the activity of NOS. Arginase also uses L-arginine as its substrate, and arginase-1 expression is highly induced in a murine model of asthma. Because we have previously described that arginase affects NOx content and interferes with the activation of NF-B in lung epithelial cells, the goal of this study was to investigate the impact of arginase inhibition on the bioavailability of NO and the implications for NF-B activation and inflammation in a mouse model of allergic airway disease. Administration of the arginase inhibitor BEC (S-(2-boronoethyl)-L-cysteine) decreased arginase activity and caused alterations in NO homeostasis, which were reflected by increases in S-nitrosylated and nitrated proteins in the lungs from inflamed mice. In contrast to our expectations, BEC enhanced perivascular and peribronchiolar lung inflammation, mucus metaplasia, NF-B DNA binding, and mRNA expression of the NF-B-driven chemokine genes CCL20 and KC, and lead to further increases in airways hyperresponsiveness. These results suggest that inhibition of arginase activity enhanced a variety of parameters relevant to allergic airways disease, possibly by altering NO homeostasis.

The Journal of Immunology, 2013

NF-κB activation within the epithelium has been implicated in the pathogenesis of asthma, yet the... more NF-κB activation within the epithelium has been implicated in the pathogenesis of asthma, yet the exact role of epithelial NF-κB in allergen-induced inflammation and airway remodeling remains unclear. In the current study, we used an intranasal house dust mite (HDM) extract exposure regimen time course in BALB/c mice to evaluate inflammation, NF-κB activation, airway hyperresponsiveness (AHR), and airway remodeling. We used CC10-IκBαSR transgenic mice to evaluate the functional importance of epithelial NF-κB in response to HDM. After a single exposure of HDM, mRNA expression of proinflammatory mediators was significantly elevated in lung tissue of wild-type (WT) mice, in association with increases in nuclear RelA and RelB, components of the classical and alternative NF-κB pathway, respectively, in the bronchiolar epithelium. In contrast, CC10-IκBαSR mice displayed marked decreases in nuclear RelA and RelB and mRNA expression of proinflammatory mediators compared with WT mice. After ...

Journal of Cellular Biochemistry, 2013

Glutathione has traditionally been considered as an antioxidant that protects cells against oxida... more Glutathione has traditionally been considered as an antioxidant that protects cells against oxidative stress. Hence, the loss of reduced glutathione and formation of glutathione disulfide is considered a classical parameter of oxidative stress that is increased in diseases. Recent studies have emerged that demonstrate that glutathione plays a more direct role in biological and pathophysiological processes through covalent modification to reactive cysteines within proteins, a process known as S-glutathionylation. The formation of an S-glutathionylated moiety within the protein can lead to structural and functional modifications. Activation, inactivation, loss of function, and gain of function have all been attributed to S-glutathionylation. In pathophysiological settings, Sglutathionylation is tightly regulated. This perspective offers a concise overview of the emerging field of protein thiol redox modifications. We will also cover newly developed methodology to detect S-glutathionylation in situ, which will enable further discovery into the role of Sglutathionylation in biology and disease.

European Respiratory Journal, 2013

Total reduced glutathione (GSH), the main pulmonary antioxidant, is increased in asthma patients ... more Total reduced glutathione (GSH), the main pulmonary antioxidant, is increased in asthma patients and, in some studies, increased amounts of oxidised glutathione (GSSG) were also found. In addition, enzymes that regulate the GSH redox cycle are altered in asthmatics (reviewed in [1]). Grx/PSSG alterations as a cause or a consequence of the disease are related to clinical manifestations.

Antioxidants & Redox Signaling, 2012

Significance: Redox-based signaling governs a number of important pathways in tissue homeostasis.... more Significance: Redox-based signaling governs a number of important pathways in tissue homeostasis. Consequently, deregulation of redox-controlled processes has been linked to a number of human diseases. Among the biological processes regulated by redox signaling, apoptosis or programmed cell death is a highly conserved process important for tissue homeostasis. Apoptosis can be triggered by a wide variety of stimuli, including death receptor ligands, environmental agents, and cytotoxic drugs. Apoptosis has also been implicated in the etiology of many human diseases. Recent Advances: Recent discoveries demonstrate that redox-based changes are required for efficient activation of apoptosis. Among these redox changes, alterations in the abundant thiol, glutathione (GSH), and the oxidative post-translational modification, protein S-glutathionylation (PSSG) have come to the forefront as critical regulators of apoptosis. Critical Issues: Although redox-based changes have been documented in apoptosis and disease pathogenesis, the mechanistic details, whereby redox perturbations intersect with pathogenic processes, remain obscure. Future Directions: Further research will be needed to understand the context in which of the members of the death receptor pathways undergo ligand dependent oxidative modifications. Additional investigation into the interplay between oxidative modifications, redox enzymes, and apoptosis pathway members are also critically needed to improve our understanding how redoxbased control is achieved. Such analyses will be important in understanding the diverse chronic diseases. In this review we will discuss the emerging paradigms in our current understanding of redox-based regulation of apoptosis with an emphasis on S-glutathionylation of proteins and the enzymes involved in this important posttranslational modification. Antioxid. Redox Signal. 16, 496-505.

Annals of the New York Academy of Sciences, 2010

Tissue fibrosis is believed to be a manifestation of dysregulated repair following injury, in ass... more Tissue fibrosis is believed to be a manifestation of dysregulated repair following injury, in association with impaired reepithelialization, and aberrant myofibroblast activation and proliferation. Numerous pathways have been linked to the pathogenesis of fibrotic lung disease, including the death receptor Fas, which contributes to apoptosis of lung epithelial cells. A redox imbalance also has been implicated in disease pathogenesis, although mechanistic details whereby oxidative changes intersect with profibrotic signaling pathways remain elusive. Oxidation of cysteines in proteins, such as Sglutathionylation (PSSG), is known to act as a regulatory event that affects protein function. This manuscript will discuss evidence that S-glutathionylation regulates death receptor induced apoptosis, and the potential implications for cysteine oxidations in the pathogenesis of in fibrotic lung disease.

American Journal of Respiratory Cell and Molecular Biology, 2007

Glutaredoxins (GRX) are antioxidant enzymes that preferentially catalyze the reduction of protein... more Glutaredoxins (GRX) are antioxidant enzymes that preferentially catalyze the reduction of protein-glutathione mixed disulfides. The formation of mixed disulfides with GSH is known as S-glutathionylation, a post-translational modification that is emerging as an important mode of redox signaling. Since asthma is a disease that is associated with increased oxidative stress and altered antioxidant defenses, we investigated the expression of GRX in a murine model of allergic airway disease. Sensitization and challenge of C57BL/6 mice with ovalbumin resulted in increased expression of GRX1 mRNA, as well as increased amounts of GRX1 protein and total GRX activity in the lung. Because GRX1 expression is prominent in bronchial epithelium, we isolated primary epithelial cells from mouse trachea to investigate the presence of GRX. Primary tracheal epithelial cells were found to express both GRX1 and 2 mRNA and detectable GRX activity. Treatment with IFN-␥ increased the expression of GRX1 and overall GRX activity, resulting in attenuation of protein S-glutathionylation. In contrast, TGF-␤1 caused decreased GRX1 expression and overall GRX activity, leading to markedly enhanced protein S-glutathionylation. GRX1 joins the cadre of antioxidant defenses known to be modulated during allergic airway inflammation.

American Journal of Respiratory Cell and Molecular Biology, 2010

Reactive oxidants such as nitrogen dioxide (NO 2) injure the pulmonary epithelium, causing airway... more Reactive oxidants such as nitrogen dioxide (NO 2) injure the pulmonary epithelium, causing airway damage and inflammation. We previously demonstrated that nuclear factor-k B (NF-kB) activation within airway epithelial cells occurs in response to NO 2 inhalation, and is critical for lipopolysaccharide-induced or antigen-induced inflammatory responses. Here, we investigated whether manipulation of NF-kB activity in lung epithelium affected severe lung injuries induced by NO 2 inhalation. Wild-type C57BL/6J, CC10-IkBa SR transgenic mice with repressed airway epithelial NF-kB function, or transgenic mice expressing a doxycycline-inducible, constitutively active I k B kinase b (CC10-rTet-CA IKKb) with augmented NF-kB function in airway epithelium, were exposed to toxic levels of 25 ppm or 50 ppm NO 2 for 6 hours a day for 1 or 3 days. In wildtype mice, NO 2 caused the activation of NF-kB in airway epithelium after 6 hours, and after 3 days resulted in severe acute lung injury, characterized by neutrophilia, peribronchiolar lesions, and increased protein, lactate dehydrogenase, and inflammatory cytokines. Compared with wild-type mice, neutrophilic inflammation and elastase activity, lung injury, and several proinflammatory cytokines were significantly suppressed in CC10-IkBa SR mice exposed to 25 or 50 ppm NO 2. Paradoxically, CC10-rTet-CA IKKb mice that received doxycycline showed no further increase in NO 2induced lung injury compared with wild-type mice exposed to NO 2 , instead displaying significant reductions in histologic parameters of lung injury, despite elevations in several proinflammatory cytokines. These intriguing findings demonstrate distinct functions of airway epithelial NF-kB activities in oxidant-induced severe acute lung injury, and suggest that although airway epithelial NF-kB activities modulate NO 2-induced pulmonary inflammation, additional NF-kB-regulated functions confer partial protection from lung injury.

American Journal of Physiology-Lung Cellular and Molecular Physiology

Obesity is associated with severe, difficult-to-control asthma, and increased airway oxidative st... more Obesity is associated with severe, difficult-to-control asthma, and increased airway oxidative stress. Mitochondrial reactive oxygen species (mROS) are an important source of oxidative stress in asthma, leading us to hypothesize that targeting mROS in obese allergic asthma might be an effective treatment. Using a mouse model of house dust mite (HDM)-induced allergic airway disease in mice fed a low- (LFD) or high-fat diet (HFD), and the mitochondrial antioxidant MitoQuinone (MitoQ), we investigated the effects of obesity and ROS on HDM-induced airway inflammation, remodeling, and airway hyperresponsiveness (AHR). Obese allergic mice showed increased lung tissue eotaxin, airway tissue eosinophilia, and AHR compared with lean allergic mice. MitoQ reduced airway inflammation, remodeling, and hyperreactivity in both lean and obese allergic mice, and tissue eosinophilia in obese-allergic mice. Similar effects were observed with decyl triphosphonium (dTPP+), the hydrophobic cationic moiet...

Antioxidants

Glutathione (GSH), a major antioxidant in mammalian cells, regulates several vital cellular proce... more Glutathione (GSH), a major antioxidant in mammalian cells, regulates several vital cellular processes, such as nutrient metabolism, protein synthesis, and immune responses. In addition to its role in antioxidant defense, GSH controls biological processes through its conjugation to reactive protein cysteines in a post-translational modification known as protein S-glutathionylation (PSSG). PSSG has recently been implicated in the pathogenesis of multiple diseases including idiopathic pulmonary fibrosis (IPF). Hallmarks of IPF include repeated injury to the alveolar epithelium with aberrant tissue repair, epithelial cell apoptosis and fibroblast resistance to apoptosis, and the accumulation of extracellular matrix and distortion of normal lung architecture. Several studies have linked oxidative stress and PSSG to the development and progression of IPF. Additionally, it has been suggested that the loss of epithelial cell homeostasis and increased apoptosis, accompanied by the release of...

Redox Biology, 2021

Background: Interleukin-1-dependent increases in glycolysis promote allergic airways disease in m... more Background: Interleukin-1-dependent increases in glycolysis promote allergic airways disease in mice and disruption of pyruvate kinase M2 (PKM2) activity is critical herein. Glutathione-S-transferase P (GSTP) has been implicated in asthma pathogenesis and regulates the oxidation state of proteins via S-glutathionylation. We addressed whether GSTP-dependent S-glutathionylation promotes allergic airways disease by promoting glycolytic reprogramming and whether it involves the disruption of PKM2. Methods: We used house dust mite (HDM) or interleukin-1β in C57BL6/NJ WT or mice that lack GSTP. Airway basal cells were stimulated with interleukin-1β and the selective GSTP inhibitor, TLK199. GSTP and PKM2 were evaluated in sputum samples of asthmatics and healthy controls and incorporated analysis of the U-BIOPRED severe asthma cohort database. Results: Ablation of Gstp decreased total S-glutathionylation and attenuated HDM-induced allergic airways disease and interleukin-1β-mediated inflammation. Gstp deletion or inhibition by TLK199 decreased the interleukin-1β-stimulated secretion of pro-inflammatory mediators and lactate by epithelial cells. 13 C-glucose metabolomics showed decreased glycolysis flux at the pyruvate kinase step in response to TLK199. GSTP and PKM2 levels were increased in BAL of HDM-exposed mice as well as in sputum of asthmatics compared to controls. Sputum proteomics and transcriptomics revealed strong correlations between GSTP, PKM2, and the glycolysis pathway in asthma. Conclusions: GSTP contributes to the pathogenesis of allergic airways disease in association with enhanced glycolysis and oxidative disruption of PKM2. Our findings also suggest a PKM2-GSTP-glycolysis signature in asthma that is associated with severe disease.

Redox Biology, 2021

Our lungs are exposed daily to airborne pollutants, particulate matter, pathogens as well as lung... more Our lungs are exposed daily to airborne pollutants, particulate matter, pathogens as well as lung allergens and irritants. Exposure to these substances can lead to inflammatory responses and may induce endogenous oxidant production, which can cause chronic inflammation, tissue damage and remodeling. Notably, the development of asthma and Chronic Obstructive Pulmonary Disease (COPD) is linked to the aforementioned irritants. Some inhaled foreign chemical compounds are rapidly absorbed and processed by phase I and II enzyme systems critical in the detoxification of xenobiotics including the glutathione-conjugating enzymes Glutathione S-transferases (GSTs). GSTs, and in particular genetic variants of GSTs that alter their activities, have been found to be implicated in the susceptibility to and progression of these lung diseases. Beyond their roles in phase II metabolism, evidence suggests that GSTs are also important mediators of normal lung growth. Therefore, the contribution of GSTs to the development of lung diseases in adults may already start in utero, and continues through infancy, childhood, and adult life. GSTs are also known to scavenge oxidants and affect signaling pathways by protein-protein interaction. Moreover, GSTs regulate reversible oxidative post-translational modifications of proteins, known as protein S-glutathionylation. Therefore, GSTs display an array of functions that impact the pathogenesis of asthma and COPD. In this review we will provide an overview of the specific functions of each class of mammalian cytosolic GSTs. This is followed by a comprehensive analysis of their expression profiles in the lung in healthy subjects, as well as alterations that have been described in (epithelial cells of) asthmatics and COPD patients. Particular emphasis is placed on the emerging evidence of the regulatory properties of GSTs beyond detoxification and their contribution to (un)healthy lungs throughout life. By providing a more thorough understanding, tailored therapeutic strategies can be designed to affect specific functions of particular GSTs.

Free Radical Biology and Medicine, 2018

all enhanced in metabolically stressed BMDMs but prevented in Grx1overexpressing BMDMs. The dimer... more all enhanced in metabolically stressed BMDMs but prevented in Grx1overexpressing BMDMs. The dimer/tetramer ratio was increased in response to metabolic stress as was HIF1a-dependent expression of GLUT1 and IL-1b. Compared to monocytes isolated from HFD-fed mice, monocyte from Grx1 Mac tg mice showed reduced priming, reduced expression of PKM2, GLUT1 and IL-1b and diminished PKM2 phosphorylation. Conclusion: Metabolic stress-induced PKM2 S-glutathionylation promotes PKM2 tetramer dissociation, phosphorylation and subsequent nuclear translocation, which, via HIF1a-dependent expression of glycolytic enzymes and inflammatory cytokines, reprograms monocyte-derived macrophages into a hyper-inflammatory phenotype. This mechanism may contribute to chronic inflammatory diseases associated with metabolic disorders.

Nature medicine, Jan 9, 2018

Idiopathic pulmonary fibrosis is characterized by excessive deposition of collagen in the lung, l... more Idiopathic pulmonary fibrosis is characterized by excessive deposition of collagen in the lung, leading to chronically impaired gas exchange and death. Oxidative stress is believed to be critical in this disease pathogenesis, although the exact mechanisms remain enigmatic. Protein S-glutathionylation (PSSG) is a post-translational modification of proteins that can be reversed by glutaredoxin-1 (GLRX). It remains unknown whether GLRX and PSSG play a role in lung fibrosis. Here, we explored the impact of GLRX and PSSG status on the pathogenesis of pulmonary fibrosis, using lung tissues from subjects with idiopathic pulmonary fibrosis, transgenic mouse models and direct administration of recombinant Glrx to airways of mice with existing fibrosis. We demonstrate that GLRX enzymatic activity was strongly decreased in fibrotic lungs, in accordance with increases in PSSG. Mice lacking Glrx were far more susceptible to bleomycin- or adenovirus encoding active transforming growth factor beta...

Annals of the American Thoracic Society, 2016

S-glutathionylation has emerged as an oxidant-induced post-translational modification of protein ... more S-glutathionylation has emerged as an oxidant-induced post-translational modification of protein cysteines that affects structure and function. The oxidoreductase glutaredoxin-1 (Glrx1), under physiological conditions, catalyzes deglutathionylation and restores the protein thiol group. The involvement of Grx1/S-glutathionylation in allergic inflammation induced by asthma-relevant allergens remains unknown. In the present study we examined the impact of genetic ablation of Glrx1 for the pathogenesis of house dust mite (HDM)-induced allergic airway disease in mice. Wild-type (WT) or Glrx1(-/-) mice in the BALB/c background were instilled intranasally with 50 μg of HDM 5 consecutive days for 3 weeks and killed 72 hours post final exposure. As expected, overall protein S-glutathionylation was increased in Glrx1(-/-) mice exposed to HDM as compared with WT animals. Total cells in the bronchoalveolar lavage fluid were similarly increased in WT and Glrx1(-/-) HDM-treated mice compared with...

Free Radical Biology and Medicine, 2015

Journal of cellular biochemistry, Jan 7, 2015

Asthma is a pulmonary disorder, with an estimated 300 million people affected worldwide. While it... more Asthma is a pulmonary disorder, with an estimated 300 million people affected worldwide. While it is thought that endogenous reactive oxygen species (ROS) and reactive nitrogen species (RNS) such as hydrogen peroxide and nitric oxide, are important mediators of natural physiological processes, inflammatory cells recruited to the asthmatic airways have an exceptional capacity for producing a variety of highly reactive ROS and RNS believed to contribute to tissue damage and chronic airways inflammation. Antioxidant defense systems form a tightly regulated network that maintains the redox environment of the intra- as well as extracellular environment. Evidence for an oxidant-antioxidant imbalance in asthmatic airways is demonstrated in a number of studies, revealing decreased total antioxidant capacity as well as lower levels of individual antioxidants. Thiols in the form of GSH and sulfhydryl groups of proteins are among the most susceptible oxidant-sensitive targets, and hence, studi...

Journal of Cell Biology, 2009

Reactive oxygen species (ROS) increase ligation of Fas (CD95), a receptor important for regulatio... more Reactive oxygen species (ROS) increase ligation of Fas (CD95), a receptor important for regulation of programmed cell death. Glutathionylation of reactive cysteines represents an oxidative modification that can be reversed by glutaredoxins (Grxs). The goal of this study was to determine whether Fas is redox regulated under physiological conditions. In this study, we demonstrate that stimulation with Fas ligand (FasL) induces S-glutathionylation of Fas at cysteine 294 independently of nicotinamide adenine dinucleotide phosphate reduced oxidase–induced ROS. Instead, Fas is S-glutathionylated after caspase-dependent degradation of Grx1, increasing subsequent caspase activation and apoptosis. Conversely, overexpression of Grx1 attenuates S-glutathionylation of Fas and partially protects against FasL-induced apoptosis. Redox-mediated Fas modification promotes its aggregation and recruitment into lipid rafts and enhances binding of FasL. As a result, death-inducing signaling complex forma...

The Journal of Immunology, 2007

Oxidative stress is a hallmark of asthma, and increased levels of oxidants are considered markers... more Oxidative stress is a hallmark of asthma, and increased levels of oxidants are considered markers of the inflammatory process. Most studies to date addressing the role of oxidants in the etiology of asthma were based on the therapeutic administration of low m.w. antioxidants or antioxidant mimetic compounds. To directly address the function of endogenous hydrogen peroxide in the pathophysiology of allergic airway disease, we comparatively evaluated mice systemically overexpressing catalase, a major antioxidant enzyme that detoxifies hydrogen peroxide, and C57BL/6 strain matched controls in the OVA model of allergic airways disease. Catalase transgenic mice had 8-fold increases in catalase activity in lung tissue, and had lowered DCF oxidation in tracheal epithelial cells, compared with C57BL/6 controls. Despite these differences, both strains showed similar increases in OVA-specific IgE, IgG1, and IgG2a levels, comparable airway and tissue inflammation, and identical increases in pr...

The Journal of Immunology, 2008

Pulmonary inflammation in asthma is orchestrated by the activity of NF-B. NO and NO synthase (NOS... more Pulmonary inflammation in asthma is orchestrated by the activity of NF-B. NO and NO synthase (NOS) activity are important modulators of inflammation. The availability of the NOS substrate, L-arginine, is one of the mechanisms that controls the activity of NOS. Arginase also uses L-arginine as its substrate, and arginase-1 expression is highly induced in a murine model of asthma. Because we have previously described that arginase affects NOx content and interferes with the activation of NF-B in lung epithelial cells, the goal of this study was to investigate the impact of arginase inhibition on the bioavailability of NO and the implications for NF-B activation and inflammation in a mouse model of allergic airway disease. Administration of the arginase inhibitor BEC (S-(2-boronoethyl)-L-cysteine) decreased arginase activity and caused alterations in NO homeostasis, which were reflected by increases in S-nitrosylated and nitrated proteins in the lungs from inflamed mice. In contrast to our expectations, BEC enhanced perivascular and peribronchiolar lung inflammation, mucus metaplasia, NF-B DNA binding, and mRNA expression of the NF-B-driven chemokine genes CCL20 and KC, and lead to further increases in airways hyperresponsiveness. These results suggest that inhibition of arginase activity enhanced a variety of parameters relevant to allergic airways disease, possibly by altering NO homeostasis.

The Journal of Immunology, 2013

NF-κB activation within the epithelium has been implicated in the pathogenesis of asthma, yet the... more NF-κB activation within the epithelium has been implicated in the pathogenesis of asthma, yet the exact role of epithelial NF-κB in allergen-induced inflammation and airway remodeling remains unclear. In the current study, we used an intranasal house dust mite (HDM) extract exposure regimen time course in BALB/c mice to evaluate inflammation, NF-κB activation, airway hyperresponsiveness (AHR), and airway remodeling. We used CC10-IκBαSR transgenic mice to evaluate the functional importance of epithelial NF-κB in response to HDM. After a single exposure of HDM, mRNA expression of proinflammatory mediators was significantly elevated in lung tissue of wild-type (WT) mice, in association with increases in nuclear RelA and RelB, components of the classical and alternative NF-κB pathway, respectively, in the bronchiolar epithelium. In contrast, CC10-IκBαSR mice displayed marked decreases in nuclear RelA and RelB and mRNA expression of proinflammatory mediators compared with WT mice. After ...

Journal of Cellular Biochemistry, 2013

Glutathione has traditionally been considered as an antioxidant that protects cells against oxida... more Glutathione has traditionally been considered as an antioxidant that protects cells against oxidative stress. Hence, the loss of reduced glutathione and formation of glutathione disulfide is considered a classical parameter of oxidative stress that is increased in diseases. Recent studies have emerged that demonstrate that glutathione plays a more direct role in biological and pathophysiological processes through covalent modification to reactive cysteines within proteins, a process known as S-glutathionylation. The formation of an S-glutathionylated moiety within the protein can lead to structural and functional modifications. Activation, inactivation, loss of function, and gain of function have all been attributed to S-glutathionylation. In pathophysiological settings, Sglutathionylation is tightly regulated. This perspective offers a concise overview of the emerging field of protein thiol redox modifications. We will also cover newly developed methodology to detect S-glutathionylation in situ, which will enable further discovery into the role of Sglutathionylation in biology and disease.

European Respiratory Journal, 2013

Total reduced glutathione (GSH), the main pulmonary antioxidant, is increased in asthma patients ... more Total reduced glutathione (GSH), the main pulmonary antioxidant, is increased in asthma patients and, in some studies, increased amounts of oxidised glutathione (GSSG) were also found. In addition, enzymes that regulate the GSH redox cycle are altered in asthmatics (reviewed in [1]). Grx/PSSG alterations as a cause or a consequence of the disease are related to clinical manifestations.

Antioxidants & Redox Signaling, 2012

Significance: Redox-based signaling governs a number of important pathways in tissue homeostasis.... more Significance: Redox-based signaling governs a number of important pathways in tissue homeostasis. Consequently, deregulation of redox-controlled processes has been linked to a number of human diseases. Among the biological processes regulated by redox signaling, apoptosis or programmed cell death is a highly conserved process important for tissue homeostasis. Apoptosis can be triggered by a wide variety of stimuli, including death receptor ligands, environmental agents, and cytotoxic drugs. Apoptosis has also been implicated in the etiology of many human diseases. Recent Advances: Recent discoveries demonstrate that redox-based changes are required for efficient activation of apoptosis. Among these redox changes, alterations in the abundant thiol, glutathione (GSH), and the oxidative post-translational modification, protein S-glutathionylation (PSSG) have come to the forefront as critical regulators of apoptosis. Critical Issues: Although redox-based changes have been documented in apoptosis and disease pathogenesis, the mechanistic details, whereby redox perturbations intersect with pathogenic processes, remain obscure. Future Directions: Further research will be needed to understand the context in which of the members of the death receptor pathways undergo ligand dependent oxidative modifications. Additional investigation into the interplay between oxidative modifications, redox enzymes, and apoptosis pathway members are also critically needed to improve our understanding how redoxbased control is achieved. Such analyses will be important in understanding the diverse chronic diseases. In this review we will discuss the emerging paradigms in our current understanding of redox-based regulation of apoptosis with an emphasis on S-glutathionylation of proteins and the enzymes involved in this important posttranslational modification. Antioxid. Redox Signal. 16, 496-505.

Annals of the New York Academy of Sciences, 2010

Tissue fibrosis is believed to be a manifestation of dysregulated repair following injury, in ass... more Tissue fibrosis is believed to be a manifestation of dysregulated repair following injury, in association with impaired reepithelialization, and aberrant myofibroblast activation and proliferation. Numerous pathways have been linked to the pathogenesis of fibrotic lung disease, including the death receptor Fas, which contributes to apoptosis of lung epithelial cells. A redox imbalance also has been implicated in disease pathogenesis, although mechanistic details whereby oxidative changes intersect with profibrotic signaling pathways remain elusive. Oxidation of cysteines in proteins, such as Sglutathionylation (PSSG), is known to act as a regulatory event that affects protein function. This manuscript will discuss evidence that S-glutathionylation regulates death receptor induced apoptosis, and the potential implications for cysteine oxidations in the pathogenesis of in fibrotic lung disease.

American Journal of Respiratory Cell and Molecular Biology, 2007

Glutaredoxins (GRX) are antioxidant enzymes that preferentially catalyze the reduction of protein... more Glutaredoxins (GRX) are antioxidant enzymes that preferentially catalyze the reduction of protein-glutathione mixed disulfides. The formation of mixed disulfides with GSH is known as S-glutathionylation, a post-translational modification that is emerging as an important mode of redox signaling. Since asthma is a disease that is associated with increased oxidative stress and altered antioxidant defenses, we investigated the expression of GRX in a murine model of allergic airway disease. Sensitization and challenge of C57BL/6 mice with ovalbumin resulted in increased expression of GRX1 mRNA, as well as increased amounts of GRX1 protein and total GRX activity in the lung. Because GRX1 expression is prominent in bronchial epithelium, we isolated primary epithelial cells from mouse trachea to investigate the presence of GRX. Primary tracheal epithelial cells were found to express both GRX1 and 2 mRNA and detectable GRX activity. Treatment with IFN-␥ increased the expression of GRX1 and overall GRX activity, resulting in attenuation of protein S-glutathionylation. In contrast, TGF-␤1 caused decreased GRX1 expression and overall GRX activity, leading to markedly enhanced protein S-glutathionylation. GRX1 joins the cadre of antioxidant defenses known to be modulated during allergic airway inflammation.

American Journal of Respiratory Cell and Molecular Biology, 2010

Reactive oxidants such as nitrogen dioxide (NO 2) injure the pulmonary epithelium, causing airway... more Reactive oxidants such as nitrogen dioxide (NO 2) injure the pulmonary epithelium, causing airway damage and inflammation. We previously demonstrated that nuclear factor-k B (NF-kB) activation within airway epithelial cells occurs in response to NO 2 inhalation, and is critical for lipopolysaccharide-induced or antigen-induced inflammatory responses. Here, we investigated whether manipulation of NF-kB activity in lung epithelium affected severe lung injuries induced by NO 2 inhalation. Wild-type C57BL/6J, CC10-IkBa SR transgenic mice with repressed airway epithelial NF-kB function, or transgenic mice expressing a doxycycline-inducible, constitutively active I k B kinase b (CC10-rTet-CA IKKb) with augmented NF-kB function in airway epithelium, were exposed to toxic levels of 25 ppm or 50 ppm NO 2 for 6 hours a day for 1 or 3 days. In wildtype mice, NO 2 caused the activation of NF-kB in airway epithelium after 6 hours, and after 3 days resulted in severe acute lung injury, characterized by neutrophilia, peribronchiolar lesions, and increased protein, lactate dehydrogenase, and inflammatory cytokines. Compared with wild-type mice, neutrophilic inflammation and elastase activity, lung injury, and several proinflammatory cytokines were significantly suppressed in CC10-IkBa SR mice exposed to 25 or 50 ppm NO 2. Paradoxically, CC10-rTet-CA IKKb mice that received doxycycline showed no further increase in NO 2induced lung injury compared with wild-type mice exposed to NO 2 , instead displaying significant reductions in histologic parameters of lung injury, despite elevations in several proinflammatory cytokines. These intriguing findings demonstrate distinct functions of airway epithelial NF-kB activities in oxidant-induced severe acute lung injury, and suggest that although airway epithelial NF-kB activities modulate NO 2-induced pulmonary inflammation, additional NF-kB-regulated functions confer partial protection from lung injury.