Acute lung injury leads to depression-like symptoms through upregulation of neutrophilic and neuronal NADPH oxidase signaling in a murine model

NADPH-oxidases as potential pharmacological targets for thrombosis and depression comorbidity

There is a complex interrelationship between the nervous system and the cardiovascular system. Comorbidities of cardiovascular diseases (CVD) with mental disorders, and vice versa, are prevalent. Adults with mental disorders such as anxiety and depression have a higher risk of developing CVD, and people with CVD have an increased risk of being diagnosed with mental disorders. Oxidative stress is one of the many pathways associated with the pathophysiology of brain and cardiovascular disease. Nicotinamide adenine dinucleotide phosphate oxidase (NOX) is one of the major generators of reactive oxygen species (ROS) in mammalian cells, as it is the enzyme that specifically produces superoxide. This review summarizes recent findings on the consequences of NOX activation in thrombosis and depression. It also discusses the therapeutic effects and pharmacological strategies of NOX inhibitors in CVD and brain disorders. A better comprehension of these processes could facilitate the development of new therapeutic approaches for the prevention and treatment of the comorbidity of thrombosis and depression.

EGR-1 Contributes to Pulmonary Edema by Regulating the Epithelial Sodium Channel in Lipopolysaccharide-Induced Acute Lung Injury

Acute lung injury (ALI) is a common lung disease with increasing morbidity and mortality rates due to the lack of specific drugs. Impaired alveolar fluid clearance (AFC) is a primary pathological feature of ALI. Epithelial sodium channel (ENaC) is a primary determinant in regulating the transport of Na+ and the clearance of alveolar edema fluid. Therefore, ENaC is an important target for the development of drugs for ALI therapy. However, the role of ENaC in the progression of ALI remains unclear. Inhibition of early growth response factor (EGR-1) expression has been reported to induce a protective effect on ALI; therefore, we evaluated whether EGR-1 participates in the progression of ALI by regulating ENaC-α in alveolar epithelium. We investigated the potential mechanism of EGR-1-mediated regulation of ENaC in ALI. We investigated whether EGR-1 aggravates the pulmonary edema response in ALI by regulating ENaC. ALI mouse models were established by intrabronchial injection of lipopolysaccharides (LPS). Lentiviruses with EGR-1 knockdown were transfected into LPS-stimulated A549 cells. We found that EGR-1 expression was upregulated in the lung tissues of ALI mice and in LPS-induced A549 cells, and was negatively correlated with ENaC-α expression. Knockdown of EGR-1 increased ENaC-α expression and relieved cellular edema in ALI. Moreover, EGR-1 regulated ENaC-α expression at the transcriptional level, and correspondingly promoted pulmonary edema and aggravated ALI symptoms. In conclusion, our study demonstrated that EGR-1 could promote pulmonary edema by downregulating ENaC-α at the transcriptional level in ALI. Our study provides a new potential therapeutic strategy for treatment of ALI.

n-3 Polyunsaturated Fatty Acids Modulate LPS-Induced ARDS and the Lung-Brain Axis of Communication in Wild-Type versus Fat-1 Mice Genetically Modified for Leukotriene B4 Receptor 1 or Chemerin Receptor 23 Knockout

Specialized pro-resolving mediators (SPMs) and especially Resolvin E1 (RvE1) can actively terminate inflammation and promote healing during lung diseases such as acute respiratory distress syndrome (ARDS). Although ARDS primarily affects the lung, many ARDS patients also develop neurocognitive impairments. To investigate the connection between the lung and brain during ARDS and the therapeutic potential of SPMs and its derivatives, fat-1 mice were crossbred with RvE1 receptor knockout mice. ARDS was induced in these mice by intratracheal application of lipopolysaccharide (LPS, 10 µg). Mice were sacrificed at 0 h, 4 h, 24 h, 72 h, and 120 h post inflammation, and effects on the lung, liver, and brain were assessed by RT-PCR, multiplex, immunohistochemistry, Western blot, and LC-MS/MS. Protein and mRNA analyses of the lung, liver, and hypothalamus revealed LPS-induced lung inflammation increased inflammatory signaling in the hypothalamus despite low signaling in the periphery. Neutrophil recruitment in different brain structures was determined by immunohistochemical staining. Overall, we showed that immune cell trafficking to the brain contributed to immune-to-brain communication during ARDS rather than cytokines. Deficiency in RvE1 receptors and enhanced omega-3 polyunsaturated fatty acid levels (fat-1 mice) affect lung-brain interaction during ARDS by altering profiles of several inflammatory and lipid mediators and glial activity markers.

Elsholtzia bodinieri Vaniot ameliorated acute lung injury in mice by regulating pyroptosis, inflammation, oxidative stress and macrophage polarization

ETHNOPHARMACOLOGICAL RELEVANCE

Elsholtzia bodinieri Vaniot, perennial herbs, a traditional Yunnan Chinese herbal medicine. Its whole herb can be used as commonly used herbs to cure fever, headache, inflammation, indigestion etc., and its tender tip can also be used as tea in Yunnan of China. However, the protective mechanism of Elsholtzia bodinieri Vaniot on acute lung injury (ALI) still needs to be explored.

AIM OF STUDY

ALI is characterized by acute respiratory inflammation, which remains a significant source of morbidity and mortality. The current study with the aim of determining the therapeutic the efficacy of E. bodinieri Vaniot on lipopolysaccharide-induced ALI, moreover uncovered the underlying gene-regulated framework, so E. bodinieri Vaniot might serve as functional food for adjuvant therapy or therapeutic agent.

MATERIALS AND METHODS

These potential pharmacological targets of E. bodinieri Vaniot against ALI were analyzed by multiple bioinformatics databases. E. bodinieri Vaniot methanol extract (EBE) was obtained by ultrasonic-assisted extraction method, and detected by UHPLC-ESI-HRMS/MS. These pyroptosis, inflammation and oxidative stress associated factors were measured using ELISA assay, western blotting, and histopathological examination to assess the effects of EBE. EcoTyper and immunofluorescence staining were employed to estimate macrophage polarization states in ALI lungs tissue.

RESULTS

In ALI lung tissues, EBE treatment could increase B cell leukemia/lymphoma 2 (BCL2) to inhibit pyroptosis, downregulate prostaglandin-endoperoxide synthase 2 (PTGS2) to attenuate inflammation, upregulating NAD(P)H dehydrogenase, quinone 1 (NQO1) to alleviate oxidative stress and induce macrophage polarization toward the M2 phenotype.

CONCLUSION

E. bodinieri Vaniot ameliorated ALI thought regulating pyroptosis, inflammation, oxidative stress and macrophage polarization, as well as could be a promising source for therapeutic agent.

Immunoregulatory mechanism of acute kidney injury in sepsis: A Narrative Review

Sepsis acute kidney injury (SAKI) is a common complication of sepsis, accounting for 26-50 % of all acute kidney injury (AKI). AKI is an independent risk factor for increased mortality risk in patients with sepsis. The excessive inflammatory cascade reaction in SAKI is one of the main causes of kidney damage. Both the innate immune system and the adaptive immune system are involved in the inflammation process of SAKI. Under the action of endotoxin, neutrophils, monocytes, macrophages, T cells and other complex immune network reactions occur, and a large number of endogenous inflammatory mediators are released, resulting in the amplification and loss of control of the inflammatory response. The study of immune cells in SAKI will help improve the understanding of the immune mechanisms of SAKI, and will lay a foundation for the development of new diagnostic and therapeutic targets. This article reviews the role of known immune mechanisms in the occurrence and development of SAKI, with a view to finding new targets for SAKI treatment.

Geniposidic acid protects lipopolysaccharide-induced acute lung injury via the TLR4/MyD88 signaling pathway in vitro and in vivo

BACKGROUND

Acute lung injury (ALI) is a common respiratory disease and is a serious threat to human health due to the lack of effective treatment. Geniposidic acid (GPA) is an iridoid glucoside extracted from Gardeniae jasminoides Ellis and can treat inflammation-related diseases. This study aimed to investigate the regulatory functions of GPA on lipopolysaccharide (LPS)-induced ALI and its potential mechanism, providing effective strategies for the clinical treatment of ALI.

METHODS

ALI models were constructed by LPS in Sprague-Dawley rats and pulmonary epithelial cells. The function of GPA was investigated by hematoxylin-eosin staining, lung function assessment, Western blot, Masson staining, and Sirius Red staining, quantitative real-time PCR, enzyme-linked immunosorbent assay, cell counting kit-8 assay, apoptosis analysis, and immunofluorescence assays.

RESULTS

Functionally, GPA increased survival, relieved pulmonary epithelial function in response to LPS, repressed pulmonary fibrosis and inflammation caused by ALI in vivo; GPA also repressed pulmonary epithelial cell injury and inflammation induced by LPS in vitro. Mechanistically, GPA decreased the protein levels of TLR4 and MyD88 and accelerated the nuclear export of p65, suggesting that GPA repressed the activation of p65.

CONCLUSION

GPA protected LPS-induced ALI through the TLR4/MyD88 signaling pathway.

A sesquiterpene isolated from the stems and leaves of Dioscorea opposita thunb. Transforms the composition of immune cells through ERβ in a mouse model of LPS-induced lung injury

Acute lung injury (ALI) is a common critical disease with a high mortality rate. Natural products have marked efficacy in the prevention and treatment of ALI, in addition, estrogen and its receptors are involved in the pathogenesis and development of lung injury. Our previous research shows that sesquiterpenes isolated from the stems and leaves of Dioscorea opposita Thunb. have anti-inflammatory and estrogenic-like activity. In the present study, sesquiterpene (A1) is a natural extract from the stems and leaves of Dioscorea opposita Thunb. with a view to determining whether A1 can improve lung function in a mouse model of LPS-induced ALI and exploring the involvement of the estrogen receptor β (ERβ) pathway. A1 (20 or 40 mg/kg, i. g., 2 times/day) was administered for 3 d, followed by the induction of ALI via an intratracheal LPS drip (5 mg/kg/2 h). The lung function and levels of inflammation, immune cells, apoptosis, and ERβ expression were examined. The antagonistic activity of specific ERβ blocker (THC, 1 μM) against A1 (20 μM) in co-cultured BEAS-2B cells and splenic lymphocytes induced with LPS (1 μg/mL, 24 h) was also investigated to assess whether the observed effects of A1 were mediated by ERβ. A1 improved lung function, regulated the immune system, and decreased inflammation and apoptosis. Moreover, A1 increased the expression of ERβ in LPS-induced mice, and antagonism of ERβ decreased the protective effects of A1 in a co-culture system. A1 had anti-ALI effects that might partially mediated through ERβ signaling. Our data provide molecular justification for the use of A1 in the treatment of ALI.

A Barrier to Defend - Models of Pulmonary Barrier to Study Acute Inflammatory Diseases

Pulmonary diseases represent four out of ten most common causes for worldwide mortality. Thus, pulmonary infections with subsequent inflammatory responses represent a major public health concern. The pulmonary barrier is a vulnerable entry site for several stress factors, including pathogens such as viruses, and bacteria, but also environmental factors e.g. toxins, air pollutants, as well as allergens. These pathogens or pathogen-associated molecular pattern and inflammatory agents e.g. damage-associated molecular pattern cause significant disturbances in the pulmonary barrier. The physiological and biological functions, as well as the architecture and homeostatic maintenance of the pulmonary barrier are highly complex. The airway epithelium, denoting the first pulmonary barrier, encompasses cells releasing a plethora of chemokines and cytokines, and is further covered with a mucus layer containing antimicrobial peptides, which are responsible for the pathogen clearance. Submucosal antigen-presenting cells and neutrophilic granulocytes are also involved in the defense mechanisms and counterregulation of pulmonary infections, and thus may directly affect the pulmonary barrier function. The detailed understanding of the pulmonary barrier including its architecture and functions is crucial for the diagnosis, prognosis, and therapeutic treatment strategies of pulmonary diseases. Thus, considering multiple side effects and limited efficacy of current therapeutic treatment strategies in patients with inflammatory diseases make experimental in vitro and in vivo models necessary to improving clinical therapy options. This review describes existing models for studyying the pulmonary barrier function under acute inflammatory conditions, which are meant to improve the translational approaches for outcome predictions, patient monitoring, and treatment decision-making.

Isorhamnetin alleviates lipopolysaccharide-induced acute lung injury by inhibiting mTOR signaling pathway

Aim: Acute Lung Injury (ALI) is an acute hypoxic respiratory insufficiency caused by various traumatic factors, manifested as progressive hypoxemia and respiratory distress, and lung imaging shows a heterogeneous osmotic outbreak. Isorhamnetin (ISO) is a flavonoid compound isolated and purified from medicinal plants, such as Hippophae rhamnoides L. and Ginkgo, and has multiple pharmacological functions, such as anti-tumor, anti-myocardial hypoxia, and cardiovascular protection. Our previous study has shown that ISO could attenuate lipopolysaccharide (LPS)-induced acute lung injury in mice, but its mechanism is not clear.Methods: In this study, we used LPS-induced mouse and cell models to research the mechanism of ISO alleviating acute lung injury.Results: The results showed that ISO could attenuate the injury of type II alveolar epithelial cells by inhibiting the TLR4/NF-κB pathway. Further studies showed that ISO could inhibit the activation of mTOR signal in vivo and in vitro and promote autophagy in alveolar epithelial cells to reduce lung injury caused by LPS. In addition, ISO could inhibit LPS-induced epithelial cell apoptosis.Conclusion: Overall, ISO could suppress injury and apoptosis of epithelial cells and activate autophagy to protect epithelial cells via inhibiting mTOR signal and attenuating LPS-induced acute lung injury in mice.

Hederasaponin C Alleviates Lipopolysaccharide-Induced Acute Lung Injury In Vivo and In Vitro Through the PIP2/NF-κB/NLRP3 Signaling Pathway

Gene transcription is governed by epigenetic regulation that is essential for the pro-inflammatory mediators surge following pathological triggers. Acute lung injury (ALI) is driven by pro-inflammatory cytokines produced by the innate immune system, which involves the nod-like receptor 3 (NLRP3) inflammasome and nuclear factor-κB (NF-κB) pathways. These two pathways are interconnected and share a common inducer the phosphatidylinositol 4,5-bisphosphate (PIP2), an epigenetic regulator of (Ribosomal ribonucleic acid (rRNA) gene transcription, to regulate inflammation by the direct inhibition of NF-κB phosphorylation and NLRP3 inflammasome activation. Herein, we report that hederasaponin C (HSC) exerted a therapeutic effect against ALI through the regulation of the PIP2/NF-κB/NLRP3 signaling pathway. In lipopolysaccharide (LPS)/lipopolysaccharide + adenosine triphosphate (LPS+ATP)-stimulated macrophages, our results showed that HSC remarkably inhibited the secretion of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α). Moreover, HSC inhibited NF-κB/p65 nuclear translocation and the binding of PIP2 to transforming growth factor-β activated kinase 1 (TAK1). The intracellular calcium (Ca²⁺) level was decreased by HSC via the PIP2 signaling pathway, which subsequently inhibited the activation of NLRP3 inflammasome. HSC markedly alleviated LPS-induced ALI, restored lung function of mice, and rescued ALI-induced mice death. In addition, HSC significantly reduced the level of white blood cells (WBC), neutrophils, and lymphocytes, as well as pro-inflammatory mediators like IL-6, IL-1β, and TNF-α. Hematoxylin and eosin (H&E) staining results suggested HSC has a significant therapeutic effect on lung injury of mice. Interestingly, the PIP2/NF-κB/NLRP3 signaling pathway was further confirmed by the treatment of HSC with ALI, which is consistent with the treatment of HSC with LPS/LPS+ATP-stimulated macrophages. Overall, our findings revealed that HSC demonstrated significant anti-inflammatory activity through modulating the PIP2/NF-κB/NLRP3 axis in vitro and in vivo, suggesting that HSC is a potential therapeutic agent for the clinical treatment of ALI.

The protective effects of apocynin in hyperoxic lung injury in neonatal rats

AIM

Inflammation and oxidate stress are significant factors in the pathogenesis of bronchopulmonary dysplasia (BPD). The aim of this study is to investigate the efficacy of apocynin (APO), an anti-inflammatory, antioxidant, and antiapoptotic drug, in the prophylaxis of neonatal hyperoxic lung injury.

METHOD

This experimental study included 40 neonatal rats divided into the control, APO, BPD, and BPD + APO groups. The control and APO groups were kept in a normal room environment, while the BPD and BPD + APO groups were kept in a hyperoxic environment. The rats in the APO and BPD + APO groups were administered intraperitoneal APO, while the control and BPD rats were administered ordinary saline. At the end of the trial, lung tissue was evaluated with respect to the degree of histopathological injury, apoptosis, oxidant and antioxidant capacity, and severity of inflammation.

RESULT

The BPD and BPD + APO groups exhibited higher mean histopathological injury and alveolar macrophage scores compared to the control and APO groups. Both scores were lower in the BPD + APO group in comparison to the BPD group. The BPD + APO group had a significantly lower average of TUNEL positive cells than the BPD group. The lung tissue examination indicated significantly higher levels of mean malondialdehyde (MDA), total oxidant status (TOS), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) in the BPD group compared to the control and APO groups. While the TNF-α and IL-1β levels of the BPD + APO group were similar to that of the control group, the MDA and TOS levels were higher compared to the controls and lower compared to the BPD group. The BPD group demonstrated significantly lower levels/activities of mean total antioxidant status, glutathione reductase, superoxide dismutase, glutathione peroxidase in comparison to the control and APO groups. While the mean antioxidant enzyme activity of the BPD + APO group was lower than the control group, it was significantly higher compared to the BPD group.

CONCLUSION

This is the first study in the literature to reveal through an experimental neonatal hyperoxic lung injury that APO, an anti-inflammatory, antioxidant, and antiapoptotic drug, exhibits protective properties against the development of BPD.

Bruton's tyrosine kinase inhibition attenuates oxidative stress in systemic immune cells and renal compartment during sepsis-induced acute kidney injury in mice

Sepsis is a life-threatening condition which affects multiple organs including the kidney. Sepsis-induced acute kidney injury (AKI) is a major health burden throughout the globe. Pathogenesis of sepsis-induced AKI is complex; however, it involves both innate and adaptive immune cells such as B cells, T cells, dendritic cells (DCs), macrophages, and neutrophils. Bruton's tyrosine kinase (BTK) is reportedly involved in inflammatory and oxidative signaling in different immune cells, however its contribution with respect to sepsis-induced AKI has not been delineated. This study attempted to investigate the role of BTK and its inhibition on oxidizing enzymes NADPH oxidase (NOX-2) and inducible nitric oxide synthase (iNOS) in DCs, neutrophils, and B cells during AKI. Our data reveal that BTK is activated in DCs, neutrophils, and B cells which causes an increase in AKI associated biochemical markers such as serum creatinine/blood urea nitrogen, renal myeloperoxidase activity, and histopathological disturbances in renal tubular structures. Activation of BTK causes upregulation of NOX-2/iNOS/nitrotyrosine in these immune cells and kidney. Treatment with BTK inhibitor, Ibrutinib causes attenuation in AKI associated dysfunction in biochemical parameters (serum creatinine/blood urea nitrogen, renal myeloperoxidase activity) and oxidative stress in immune cells and kidney (iNOS/NOX2/lipid peroxides/nitrotyrosine/protein carbonyls). In summary, the current investigation reveals a compelling role of BTK signaling in sepsis-induced AKI which is evident from amelioration of AKI associated renal dysfunction after its inhibition.

Understanding the role of neutrophils in acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is difficult to treat and is associated with a high mortality rate. The most severe form of coronavirus disease 2019 (COVID-19) also leads to life-threatening ARDS. Neutrophil counts are positively correlated with disease severity in ARDS. Neutrophil activation not only plays a significant role in immune defense against infections, but also causes tissue damage and leads to inflammatory diseases. Activated neutrophils rapidly migrate to inflamed lung tissue, releasing toxic granular contents and generating neutrophil extracellular traps. In the last few decades, it has become apparent that neutrophils occupy a central role in ARDS pathology. In this review, we summarize the neutrophil inflammatory responses and their relationships to ARDS. According to the current literature, understanding the function of neutrophils may be helpful in the treatment of ARDS.

The Redox Role of G6PD in Cell Growth, Cell Death, and Cancer

The generation of reducing equivalent NADPH via glucose-6-phosphate dehydrogenase (G6PD) is critical for the maintenance of redox homeostasis and reductive biosynthesis in cells. NADPH also plays key roles in cellular processes mediated by redox signaling. Insufficient G6PD activity predisposes cells to growth retardation and demise. Severely lacking G6PD impairs embryonic development and delays organismal growth. Altered G6PD activity is associated with pathophysiology, such as autophagy, insulin resistance, infection, inflammation, as well as diabetes and hypertension. Aberrant activation of G6PD leads to enhanced cell proliferation and adaptation in many types of cancers. The present review aims to update the existing knowledge concerning G6PD and emphasizes how G6PD modulates redox signaling and affects cell survival and demise, particularly in diseases such as cancer. Exploiting G6PD as a potential drug target against cancer is also discussed.

Oxidative and inflammatory mediators are upregulated in neutrophils of autistic children: Role of IL-17A receptor signaling

Autism spectrum disorder (ASD) is characterized by repetitive behaviors, impaired social communication and stereotyped interests, and often associated with dysregulations in innate/adaptive immune cells. IL-17A has been linked with abnormal behavioral patterns observed in autistic children and animal models of autism. However, it is yet to be investigated if IL-17A and its receptors are implicated in regulation of oxidative and inflammatory mediators in neutrophils of ASD patients. Therefore, we pursued to identify the effect of IL-17 receptor (IL-17R), and its inflammatory potential in neutrophils from ASD (n = 45) and typically developing control (TDC; n = 40) subjects. IL-17A, its receptor (IL-17R), associated signaling pathways [nuclear transcription factor nuclear factor-kappa B (NF-κB), IL-6 and oxidative stress parameters such as NADPH oxidase (NOX2), inducible nitric oxide synthase (iNOS), reactive oxygen species (ROS), and nitrotyrosine] were determined in the neutrophils from TDC and ASD subjects. Our data show that IL-17A expression, and IL-17R are increased in neutrophils of ASD patients. Further, inflammatory signaling pathways such as such as phospho-NFκB, and ROS generating enzymes, i.e. NOX2/iNOS are increased in neutrophils of ASD patients as compared TDC subjects. Furthermore, activation of IL-17A/IL-17R signaling in neutrophils of ASD subjects leads to upregulation of phospho-NFκB, IL-6 and NOX2/ROS, thus suggesting a compelling role of IL-17A in modulation of inflammation. Our study displays for the first time that IL-17A/IL-17R signaling in neutrophils could play a pivotal role in autism through upregulation of oxidative and inflammatory mediators.

Inhibition of spleen tyrosine kinase signaling protects against acute lung injury through blockade of NADPH oxidase and IL-17A in neutrophils and γδ T cells respectively in mice

Acute lung injury (ALI) is one of the most serious complications in critically ill patients which often leads to morbidity and mortality. ALI characterized by severe inflammation of lungs occurs due to uncontrolled inflammatory immune response. However, the immunological mechanism(s) are far from being understood. The spleen tyrosine kinase (SYK), a key component of immune receptor signaling, plays a critical role in the modulation of inflammatory signaling in different immune cells. However, its role in ALI remains to be explored. Therefore, in this study, we investigated the effect of R406, a SYK inhibitor in lipopolysaccharide (LPS)-induced ALI mouse model. LPS led to increased SYK expression in neutrophils and gamma delta (γδ) T cells. This was associated with increased neutrophilic airway inflammation, vascular permeability, myeloperoxidase activity in the lung with upregulated expression of NADPH oxidase (NOX2)/MCP-1/TNF-α in neutrophils and IL-17A in γδ T cells/lung. Pulmonary inflammation was associated with higher mortality in mice with ALI. Inhibition of SYK signaling using R406 in the lung led to blockade of neutrophilic airway inflammation, vascular permeability, pro-inflammatory cytokine release and oxidative stress in innate immune cells, i.e. γδ T cells and neutrophils and the lung. R406 administered LPS group had better survival rate than LPS group. This suggests that SYK upregulation in γδ T cells and neutrophils plays an important role in inflammatory process during ALI. In conclusion, R406 exhibited a great potential to block the LPS-induced airway inflammation and mortality which could be developed as a potential future therapy in ALI.

Glucose-6-phosphate dehydrogenase inhibition attenuates acute lung injury through reduction in NADPH oxidase-derived reactive oxygen species

Acute lung injury (ALI) is a heterogeneous disease with the hallmarks of alveolar capillary membrane injury, increased pulmonary oedema and pulmonary inflammation. The most common direct aetiological factor for ALI is usually parenchymal lung infection or haemorrhage. Reactive oxygen species (ROS) generated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX2) are thought to play an important role in the pathophysiology of ALI. Glucose-6-phosphate dehydrogenase (G6PD) plays an important role both in production of ROS as well as their removal through the supply of NADPH. However, how G6PD modulation affects NOX2-mediated ROS in the airway epithelial cells (AECs) during acute lung injury has not been explored previously. Therefore, we investigated the effect of G6PD inhibitor, 6-aminonicotinamide on G6PD activity, NOX2 expression, ROS production and enzymatic anti-oxidants in AECs in a mouse model of ALI induced by lipopolysaccharide (LPS). ALI led to increased G6PD activity in the AECs with concomitant elevation of NOX2, ROS, SOD1 and nitrotyrosine. G6PD inhibitor led to reduction of LPS-induced airway inflammation, bronchoalveolar lavage fluid protein concentration as well as NOX2-derived ROS and subsequent oxidative stress. Conversely, ALI led to decreased glutathione reductase activity in AECs, which was normalized by G6PD inhibitor. These data show that activation of G6PD is associated with enhancement of oxidative inflammation in during ALI. Therefore, inhibition of G6PD might be a beneficial strategy during ALI to limit oxidative damage and ameliorate airway inflammation.