Therapeutic Potential of Pentoxifylline in Paraquat-Induced Pulmonary Toxicity: Role of the Phosphodiesterase Enzymes.

Pentoxifylline (PTX), a non-selective phosphodiesterase inhibitor, has demonstrated protective effects against lung injury in animal models. Given the significance of pulmonary toxicity resulting from paraquat (PQ) exposure, the present investigation was designed to explore the impact of PTX on PQ-induced pulmonary oxidative impairment in male mice.Following preliminary studies, thirty-six mice were divided into six groups. Group 1 received normal saline, group 2 received a single dose of PQ (20 mg/kg; i.p.), and group 3 received PTX (100 mg/kg/day; i.p.). Additionally, treatment groups 4-6 were received various doses of PTX (25, 50, and 100 mg/kg/day; respectively) one hour after a single dose of PQ. After 72 hours, the animals were sacrificed, and lung tissue was collected.PQ administration caused a significant decrease in hematocrit and an increase in blood potassium levels. Moreover, a notable increase was found in the lipid peroxidation (LPO), nitric oxide (NO), and myeloperoxidase (MPO) levels, along with a notable decrease in total thiol (TTM) and total antioxidant capacity (TAC) contents, catalase (CAT) and superoxide dismutase (SOD) enzymes activity in lung tissue. PTX demonstrated the ability to improve hematocrit levels; enhance SOD activity and TTM content; and decrease MPO activity, LPO and NO levels in PQ-induced pulmonary toxicity. Furthermore, these findings were well-correlated with the observed lung histopathological changes.In conclusion, our results suggest that the high dose of PTX may ameliorate lung injury by improving the oxidant/antioxidant balance in animals exposed to PQ.

FGF10 protects against particulate matter-induced lung injury by inhibiting ferroptosis via Nrf2-dependent signaling.

Particulate matter (PM) is considered the fundamental component of atmospheric pollutants and is associated with the pathogenesis of many respiratory diseases. Fibroblast growth factor 10 (FGF10) mediates mesenchymal-epithelial signaling and has been linked with the repair process of PM-induced lung injury (PMLI). However, the pathogenic mechanism of PMLI and the specific FGF10 protective mechanism against this injury are still undetermined. PM was administered in vivo into murine airways or in vitro to human bronchial epithelial cells (HBECs), and the inflammatory response and ferroptosis-related proteins SLC7A11 and GPX4 were assessed. The present research investigates the FGF10-mediated regulation of ferroptosis in PMLI mice models in vivo and HBECs in vitro. The results showed that FGF10 pretreatment reduced PM-mediated oxidative damage and ferroptosis in vivo and in vitro. Furthermore, FGF10 pretreatment led to reduced oxidative stress, decreased secretion of inflammatory mediators, and activation of the Nrf2-dependent antioxidant signaling. Additionally, silencing of Nrf2 using siRNA in the context of FGF10 treatment attenuated the effect on ferroptosis. Altogether, both in vivo and in vitro assessments confirmed that FGF10 protects against PMLI by inhibiting ferroptosis via the Nrf2 signaling. Thus, FGF10 can be used as a novel ferroptosis suppressor and a potential treatment target in PMLI.

Imidacloprid-induced lung injury in mice: Activation of the PI3K/AKT/NF-κB signaling pathway via TLR4 receptor engagement.

Significant impairment of pulmonary function has been demonstrated through long-term exposure to neonicotinoid insecticides, such as imidacloprid (IMI). However, the underlying mechanisms of lung injury induced by IMI remain unclear. In this study, a mouse model of IMI-induced pulmonary injury was established, and the toxicity and lung damage were assessed through mouse body weight, organ index, hematological parameters, and histopathological analysis of lung tissues. Furthermore, metabolomics and transcriptomics techniques were employed to explore the mechanistic aspects. Results from the toxicity assessments indicated that mouse body weight was significantly reduced by IMI, organ index was disturbed, and hematological parameters were disrupted, resulting in pulmonary injury. The mechanistic experimental results indicate that the differences in metabolites and gene expression in mouse lungs could be altered by IMI. Validation of the results through combined analysis of metabolomics and transcriptomics revealed that the mechanism by which IMI induces lung injury in mice might be associated with the activation of the TLR4 receptor, thereby activating the PI3K/AKT/NF-κB signaling pathway to induce inflammation in mouse lungs. This study provided valuable insights into the mechanisms underlying IMI-induced pulmonary damage, potentially contributing to the development of safer pest control strategies. The knowledge gained served as a robust scientific foundation for the prevention and treatment of IMI-related pulmonary injuries.

Short- and long-term outcomes of pulmonary exposure to a sublethal dose of ricin in mice.

Ricin, an extremely potent toxin produced from the seeds of castor plant, Ricinus communis, is ribosome-inactivating protein that blocks cell-protein synthesis. It is considered a biological threat due to worldwide availability of castor beans, massive quantities as a by-product of castor oil production, high stability and ease of production. The consequence of exposure to lethal dose of ricin was extensively described in various animal models. However, it is assumed that in case of aerosolized ricin bioterror attack, the majority of individuals would be exposed to sublethal doses rather than to lethal ones. Therefore, the purpose of current study was to assess short- and long-term effects on physiological parameters and function following sublethal pulmonary exposure. We show that in the short-term, sublethal exposure of mice to ricin resulted in acute lung injury, including interstitial pneumonia, cytokine storm, neutrophil influx, edema and cellular death. This damage was manifested in reduced lung performance and physiological function. Interestingly, although in the long-term, mice recovered from acute lung damage and restored pulmonary and physiological functionality, the reparative process was associated with lasting fibrotic lesions. Therefore, restriction of short-term acute phase of the disease and management of long-term pulmonary fibrosis by medical countermeasures is expected to facilitate the quality of life of exposed survivors.

Human Muse cells isolated from preterm- and term-umbilical cord delivered therapeutic effects in rat bleomycin-induced lung injury model without immunosuppressant.

BACKGROUND: Bleomycin (BLM)-induced lung injury is characterized by mixed histopathologic changes with inflammation and fibrosis, such as observed in human patients with bronchopulmonary dysplasia, idiopathic pulmonary fibrosis, and chronic obstructive pulmonary disease. Although no curative therapies for these lung diseases exist, stem cell therapy has emerged as a potential therapeutic option. Multilineage-differentiating stress-enduring (Muse) cells are endogenous pluripotent- and macrophage-like stem cells distributed in various adult and fetal tissues as stage-specific embryonic antigen-3-positive cells. They selectively home to damaged tissue by sensing sphingosine-1-phosphate and replace the damaged/apoptotic cells by in vivo differentiation. Clinical trials for some human diseases suggest the safety and therapeutic efficacy of intravenously injected human leukocyte antigen-mismatched allogenic Muse cells from adult bone marrow (BM) without immunosuppressant. Here, we evaluated the therapeutic effects of human Muse cells from preterm and term umbilical cord (UC), and adult BM in a rat BLM-induced lung injury model. METHODS: Rats were endotracheally administered BLM to induce lung injury on day 0. On day 3, human preterm UC-Muse, term UC-Muse, or adult BM-Muse cells were administered intravenously without immunosuppressants, and rats were subjected to histopathologic analysis on day 21. Body weight, serum surfactant protein D (SP-D) levels, and oxygen saturation (SpO2) were monitored. Histopathologic lung injury scoring by the Ashcroft and modified American Thoracic Society document scales, quantitative characterization of engrafted Muse cells, RNA sequencing analysis, and in vitro migration assay of infused Muse cells were performed. RESULTS: Rats administered preterm- and term-UC-Muse cells exhibited a significantly better recovery based on weight loss, serum SP-D levels, SpO2, and histopathologic lung injury scores, and a significantly higher rate of both Muse cell homing to the lung and alveolar marker expression (podoplanin and prosurfactant protein-C) than rats administered BM-Muse cells. Rats receiving preterm-UC-Muse cells showed statistically superior results to those receiving term-UC-Muse cells in many of the measures. These findings are thought to be due to higher expression of genes related to cell migration, lung differentiation, and cell adhesion. CONCLUSION: Preterm UC-Muse cells deliver more efficient therapeutic effects than term UC- and BM-Muse cells for treating BLM-induced lung injury in a rat model.

Oxidative Stress: An Intersection Between Radiation and Sulfur Mustard Lung Injury.

Nuclear and chemical weapons of mass destruction share both a tragic and beneficial legacy in mankind's history and health. The horrific health effects of ionizing radiation and mustard gas exposures unleashed during disasters, wars, and conflicts have been harnessed to treat human health maladies. Both agents of destruction have been transformed into therapies to treat a wide range of cancers. The discovery of therapeutic uses of radiation and sulfur mustard was largely due to observations by clinicians treating victims of radiation and sulfur mustard gas exposures. Clinicians identified vulnerability of leukocytes to these agents and repurposed their use in the treatment of leukemias and lymphomas. Given the overlap in therapeutic modalities, it goes to reason that there may be common mechanisms to target as protective strategies against their damaging effects. This commentary will highlight oxidative stress as a common mechanism shared by both radiation and sulfur mustard gas exposures and discuss potential therapies targeting oxidative stress as medical countermeasures against the devastating lung diseases wrought by these agents.

The antagonism mechanism of astilbin against cadmium-induced injury in chicken lungs via Treg/Th1 balance signaling pathway.

The purpose of this study was to investigate the effect of Treg/Th1 imbalance in cadmium-induced lung injury and the potential protective effect of astilbin against cadmium-induced lung injury in chicken. Cadmium exposure significantly decreased T-AOC and GSH-Px levels and SOD activity in the chicken lung tissues. In contrast, it significantly increased the MDA and NO levels. These results indicate that cadmium triggers oxidative stress in lungs. Histopathological analysis revealed that cadmium exposure further induced infiltration of lymphocytes in the chicken lungs, indicating that cadmium causes pulmonary damage. Further analysis revealed that cadmium decreased the expression of IL-4 and IL-10 but increased those of IL-17, Foxp3, TNF-α, and TGF-ß, indicating that the exposure of cadmium induced the imbalance of Treg/Th1. Moreover, cadmium adversely affected chicken lung function by activating the NF-kB pathway and inducing expression of genes downstream to these pathways (COX-2, iNOS), associated with inflammatory injury in the lung tissue. Astilbin reduced cadmium-induced oxidative stress and inflammation in the lungs by increasing antioxidant enzyme activities and restoring Treg/Th1 balance. In conclusion, our results suggest that astilbin treatment alleviated the effects of cadmium-mediated lung injury in chickens by restoring the Treg/Th1 balance.

Synergistic interaction of co-exposure to humidifier disinfectant chemicals CMIT/MIT and PHMG in lung injury.

A number of biocidal disinfectant chemicals are used as household products to prevent spread of pathogens. People are commonly exposed to multiple chemicals through those disinfectants. However, effects of interactions (e.g., synergism) between disinfectants on human health outcomes have been rarely studied. In this study, we aimed to investigate associations of a mixture of chloromethylisothiazolinone/methylisothiazolinone (CMIT/MIT) and polyhexamethylene guanidine (PHMG), which had been used as humidifier disinfectants (HDs) in South Korea, with HD-associated lung injury (HDLI) in a Korean population (n = 4058) with HD exposure through use of HD products. Exposure to HD was retrospectively assessed by an interview-based standardized survey, and HDLI was determined by clinical assessment. After adjusting for covariates, PHMG-specific exposure indices (e.g., amount of use, indoor air concentration, and weekly exposure level) were dose-dependently associated with HDLI (their odds ratios for the comparison of third tertile versus first tertile were 1.95, 1.77, and 2.16, respectively). CMIT/MIT exposure was not observed to have a significant association with HDLI in a single chemical exposure model; however, associations between PHMG exposure and HDLI were strengthened by co-exposure to CMIT/MIT in combined chemical exposure models, where synergistic interactions between CMIT/MIT use and PHMG indices (amount of use and weekly exposure level) were observed (p-interaction in additive scale: 0.02 and 0.03, respectively). Our findings imply that adverse effects of PHMG exposure on lung injury among HD users might be worsened by co-exposure to CMIT/MIT. Given that plenty of household products contain disinfectants on global markets, epidemiological and toxicological investigations are warranted on interaction effects of co-exposure to disinfectants.

Low-level PM2.5 induces the occurrence of early pulmonary injury by regulating circ_0092363.

The significant correlation between particulate matter with aerodynamic diameters of ≤ 2.5 µm (PM2.5) and the high morbidity and mortality of respiratory diseases has become the consensus of the research. Epidemiological studies have clearly pointed out that there is no safe concentration of PM2.5, and mechanism studies have also shown that exposure to PM2.5 will first cause pulmonary inflammation. Therefore, the purpose of this study is to explore the mechanism of early lung injury induced by low-level PM2.5 from the perspective of epigenetics. Based on the previous results of population samples, combined with an in vitro/vivo exposure model of PM2.5, it was found that low-level PM2.5 promoted the transport of circ_0092363 from intracellular to extracellular spaces. The decreased expression of intracellular circ_0092363 resulted in reduced absorption of miR-31-5p, leading to inhibition of Rho associated coiled-coil containing protein kinase 1 (ROCK1) and the subsequent abnormal expression of tight junction proteins such as Zonula occludens protein 1 (ZO-1) and Claudin-1, ultimately inducing the occurrence of early pulmonary injury. Furthermore, this study innovatively introduced organoid technology and conducted a preliminary exploration for a study of the relationship among environmental exposure genomics, epigenetics and disease genomics in organoids. The role of circ_0092363 in early pulmonary injury induced by low-level PM2.5 was elucidated, and its value as a potential diagnostic biomarker was confirmed.

Identifying piRNAs that regulate BaP-induced lung injuries: A bottom-up approach from toxicity pathway investigation to animal validation.

PIWI-interacting RNAs (piRNAs) is an emerging class of small non-coding RNAs that has been recently reported to have functions in infertility, tumorigenesis, and multiple diseases in humans. Previously, 5 toxicity pathways were proposed from hundreds of toxicological studies that underlie BaP-induced lung injuries, and a "Bottom-up" approach was established to identify small non-coding RNAs that drive BaP-induced pulmonary effects by investigating the activation of these pathways in vitro, and the expression of the candidate microRNAs were validated in tissues of patients with lung diseases from publications. Here in this study, we employed the "Bottom-up" approach to identifying the roles of piRNAs and further validated the mechanisms in vivo using mouse acute lung injury model. Specifically, by non-coding RNA profiling in in vitro BaP exposure, a total of 3 suppressed piRNAs that regulate 5 toxicity pathways were proposed, including piR-004153 targeting CYP1A1, FGFR1, ITGA5, IL6R, NGRF, and SDHA, piR-020326 targeting CDK6, and piR-020388 targeting RASD1. Animal experiments demonstrated that tail vein injection of respective formulated agomir-piRNAs prior to BaP exposure could all alleviate acute lung injury that was shown by histopathological and biochemical evidences. Immunohistochemical evaluation focusing on NF-kB and Bcl-2 levels showed that exogenous piRNAs protect against BaP-induced inflammation and apoptosis, which further support that the inhibition of the 3 piRNAs had an important impact on BaP-induced lung injuries. This mechanism-driven, endpoint-supported result once again confirmed the plausibility and efficiency of the approach integrating in silico, in vitro, and in vivo evidences for the purpose of identifying key molecules.

Inhibition of GBP5 activates autophagy to alleviate inflammatory response in LPS-induced lung injury in mice.

BACKGROUND: Pulmonary emphysema is a condition that causes damage to the lung tissue over time. GBP5, as part of the guanylate-binding protein family, is dysregulated in mouse pulmonary emphysema. However, the role of GBP5 in lung inflammation in ARDS remains unveiled. METHODS: To investigate whether GBP5 regulates lung inflammation and autophagy regulation, the study employed a mouse ARDS model and MLE-12 cell culture. Vector transfection was performed for the genetic manipulation of GBP5. Then, RT-qPCR, WB and IHC staining were conducted to assess its transcriptional and expression levels. Histological features of the lung tissue were observed through HE staining. Moreover, ELISA was conducted to evaluate the secretion of inflammatory cytokines, autophagy was assessed by immunofluorescent staining, and MPO activity was determined using a commercial kit. RESULTS: Our study revealed that GBP5 expression was altered in mouse ARDS and LPS-induced MLE-12 cell models. Moreover, the suppression of GBP5 reduced lung inflammation induced by LPS in mice. Conversely, overexpression of GBP5 diminished the inhibitory impact of LPS on ARDS during autophagy, leading to increased inflammation. In the cell line of MLE-12, GBP5 exacerbates LPS-induced inflammation by blocking autophagy. CONCLUSION: The study suggests that GBP5 facilitates lung inflammation and autophagy regulation. Thus, GBP5 could be a potential therapeutic approach for improving ARDS treatment outcomes, but further research is required to validate these findings.

Lung fibroblast-derived extracellular vesicles and soluble factors alleviate elastase-induced lung injury.

One of the main pathological features of chronic obstructive pulmonary disease (COPD) is the loss of functional alveolar tissue as a consequence of impaired regenerative capacities (emphysema). Recent research suggests that the secretome from mesenchymal cells, particularly extracellular vesicles (EVs), may possess regenerative properties beneficial for lung repair. However, the regenerative potential of the soluble factors (SFs) within the secretome remains largely unexplored in COPD. To this extent, we purified EVs and SFs secreted by lung fibroblasts to generate EV-enriched and SF-enriched fractions, and evaluated their effects on elastase-induced lung injury in both precision-cut lung slices (PCLS) and a mouse model. EV- and SF-enriched fractions were concentrated and purified from the conditioned medium of cultured MRC-5 lung fibroblasts using a combination of ultrafiltration and size exclusion chromatography, and were subsequently characterized according to the MISEV guidelines. Treatment with EV- or SF-enriched concentrates prevented and improved elastase-induced emphysema in PCLS, leading to reduced lung injury and upregulated markers of alveolar epithelial cells (aquaporin 5 and surfactant protein C), indicating potential parenchymal regeneration. Accordingly, prophylactic intratracheal treatment with lung fibroblast-derived EV- and SF-enriched concentrates in vivo attenuated elastase-induced lung tissue destruction, improved lung function, and enhanced gene expression of alveolar epithelial cell markers. Here, alveolar repair not only serves the purpose of facilitating gas exchange, but also by reinstating the essential parenchymal tethering required for optimal airway mechanics. In conclusion, this study highlights the therapeutic potential of both lung fibroblast-derived EV- and SF-enriched concentrates for the treatment of lung injury and emphysema.

Microscopic computed tomography with AI-CNN-powered image analysis: the path to phenotype bleomycin-induced lung injury.

Bleomycin (BLM)-induced lung injury in mice is a valuable model for investigating the molecular mechanisms that drive inflammation and fibrosis and for evaluating potential therapeutic approaches to treat the disease. Given high variability in the BLM model, it is critical to accurately phenotype the animals in the course of an experiment. In the present study, we aimed to demonstrate the utility of microscopic computed tomography (µCT) imaging combined with an artificial intelligence (AI)-convolutional neural network (CNN)-powered lung segmentation for rapid phenotyping of BLM mice. µCT was performed in freely breathing C57BL/6J mice under isoflurane anesthesia on days 7 and 21 after BLM administration. Terminal invasive lung function measurement and histological assessment of the left lung collagen content were conducted as well. µCT image analysis demonstrated gradual and time-dependent development of lung injury as evident by alterations in the lung density, air-to-tissue volume ratio, and lung aeration in mice treated with BLM. The right and left lung were unequally affected. µCT-derived parameters such as lung density, air-to-tissue volume ratio, and nonaerated lung volume correlated well with the invasive lung function measurement and left lung collagen content. Our study demonstrates the utility of AI-CNN-powered µCT image analysis for rapid and accurate phenotyping of BLM mice in the course of disease development and progression.NEW & NOTEWORTHY Microscopic computed tomography (µCT) imaging combined with an artificial intelligence (AI)-convolutional neural network (CNN)-powered lung segmentation is a rapid and powerful tool for noninvasive phenotyping of bleomycin mice over the course of the disease. This, in turn, allows earlier and more reliable identification of therapeutic effects of new drug candidates, ultimately leading to the reduction of unnecessary procedures in animals in pharmacological research.

A multi-omics investigation of the lung injury induced by PM2.5 at environmental levels via the lung-gut axis.

Long-term exposure to fine particulate matter (PM2.5) posed injury for gastrointestinal and respiratory systems, ascribing with the lung-gut axis. However, the cross-talk mechanisms remain unclear. Here, we attempted to establish the response networks of lung-gut axis in mice exposed to PM2.5 at environmental levels. Male Balb/c mice were exposed to PM2.5 (dose of 0.1, 0.5, and 1.0 mg/kg) collected from Chengdu, China for 10 weeks, through intratracheally instillation, and examined the effect of PM2.5 on lung functions of mice. The changes of lung and gut microbiota and metabolic profiles of mice in different groups were determined. Furthermore, the results of multi-omics were conjointly analyzed to elucidate the primary microbes and the associated metabolites in lung and gut responsible for PM2.5 exposure. Accordingly, the cross-talk network and key pathways between lung-gut axis were established. The results indicated that exposed to PM2.5 0.1 mg/kg induced obvious inflammations in mice lung, while emphysema was observed at 1.0 mg/kg. The levels of metabolites guanosine, hypoxanthine, and hepoxilin B3 increased in the lung might contribute to lung inflammations in exposure groups. For microbiotas in lung, PM2.5 exposure significantly declined the proportions of Halomonas and Lactobacillus. Meanwhile, the metabolites in gut including L-tryptophan, serotonin, and spermidine were up-regulated in exposure groups, which were linked to the decreasing of Oscillospira and Helicobacter in gut. Via lung-gut axis, the activations of pathways including Tryptophan metabolism, ABC transporters, Serotonergic synapse, and Linoleic acid metabolism contributed to the cross-talk between lung and gut tissues of mice mediated by PM2.5. In summary, the microbes including Lactobacillus, Oscillospira, and Parabacteroides, and metabolites including hepoxilin B3, guanosine, hypoxanthine, L-tryptophan, and spermidine were the main drivers. In this lung-gut axis study, we elucidated some pro- and pre-biotics in lung and gut microenvironments contributed to the adverse effects on lung functions induced by PM2.5 exposure.

CircRNA: a rising therapeutic strategy for lung injury induced by pulmonary toxicants.

Lung injury has been a serious medical problem that requires new therapeutic approaches and biomarkers. Circular RNAs (circRNAs) are non-coding RNAs (ncRNAs) that exist widely in eukaryotes. CircRNAs are single-stranded RNAs that form covalently closed loops. CircRNAs are significant gene regulators that have a role in the development, progression, and therapy of lung injury by controlling transcription, translating into protein, and sponging microRNAs (miRNAs) and proteins. Although the study of circRNAs in lung injury caused by pulmonary toxicants is just beginning, several studies have revealed their expression patterns. The function that circRNAs perform in relation to pulmonary toxicants (severe acute respiratory distress syndrome coronavirus-2 (SARS-CoV-2), drug abuse, PM2.5, and cigarette smoke) is the main topic of this review. A variety of circRNAs can serve as potential biomarkers of lung injury. In this review, the biogenesis, properties, and biological functions of circRNAs were concluded, and the relationship between circRNAs and pulmonary toxicants was discussed. It is expected that the new ideas and potential treatment targets that circRNAs provide would be beneficial to research into the molecular mechanisms behind lung injury.

Green tea polyphenols inhibit TBBPA-induced lung injury via enhancing antioxidant capacity and modulating the NF-κB pathway in mice.

Tetrabromobisphenol A (TBBPA) is a global pollutant. When TBBPA is absorbed by the body through various routes, it can have a wide range of harmful effects on the body. Green tea polyphenols (GTPs) can act as antioxidants, resisting the toxic effects of TBBPA on animals. The effects and mechanisms of GTP and TBBPA on oxidative stress, inflammation and apoptosis in the mouse lung are unknown. Therefore, we established in vivo and in vitro models of TBBPA exposure and GTP antagonism using C57 mice and A549 cells and examined the expression of factors related to oxidative stress, autophagy, inflammation and apoptosis. The results of the study showed that the increase in reactive oxygen species (ROS) levels after TBBPA exposure decreased the expression of autophagy-related factors Beclin1, LC3-II, ATG3, ATG5, ATG7 and ATG12 and increased the expression of p62; oxidative stress inhibits autophagy levels. The increased expression of the pro-inflammatory factors IL-1ß, IL-6 and TNF-α decreased the expression of the anti-inflammatory factor IL-10 and activation of the NF-κB p65/TNF-α pathway. The increased expression of Bax, caspase-3, caspase-7 and caspase-9 and the decreased expression of Bcl-2 activate apoptosis-related pathways. The addition of GTP attenuated oxidative stress levels, restored autophagy inhibition and reduced the inflammation and apoptosis levels. Our results suggest that GTP can attenuate the toxic effects of TBBPA by modulating ROS, reducing oxidative stress levels, increasing autophagy and attenuating inflammation and apoptosis in mouse lung and A549 cells. These results provide fundamental information for exploring the antioxidant mechanism of GTP and further for studying the toxic effects of TBBPA.

Ultra-sensitive analysis of exhaled biomarkers in ozone-exposed mice via PAI-TOFMS assisted with machine learning algorithms.

Ground-level ozone ranks sixth among common air pollutants. It worsens lung diseases like asthma, emphysema, and chronic bronchitis. Despite recent attention from researchers, the link between exhaled breath and ozone-induced injury remains poorly understood. This study aimed to identify novel exhaled biomarkers in ozone-exposed mice using ultra-sensitive photoinduced associative ionization time-of-flight mass spectrometry and machine learning. Distinct ion peaks for acetonitrile (m/z 42, 60, and 78), butyronitrile (m/z 70, 88, and 106), and hydrogen sulfide (m/z 35) were detected. Integration of tissue characteristics, oxidative stress-related mRNA expression, and exhaled breath condensate free-radical analysis enabled a comprehensive exploration of the relationship between ozone-induced biological responses and potential biomarkers. Under similar exposure levels, C57BL/6 mice exhibited pulmonary injury characterized by significant inflammation, oxidative stress, and cardiac damage. Notably, C57BL/6 mice showed free radical signals, indicating a distinct susceptibility profile. Immunodeficient non-obese diabetic Prkdc-/-/Il2rg-/- (NPI) mice exhibited minimal biological responses to pulmonary injury, with little impact on the heart. These findings suggest a divergence in ozone-induced damage pathways in the two mouse types, leading to alterations in exhaled biomarkers. Integrating biomarker discovery with comprehensive biopathological analysis forms a robust foundation for targeted interventions to manage health risks posed by ozone exposure.

Role of macrophage bioenergetics in N-acetylcysteine-mediated mitigation of lung injury and oxidative stress induced by nitrogen mustard.

Nitrogen mustard (NM) is a toxic vesicant that causes acute injury to the respiratory tract. This is accompanied by an accumulation of activated macrophages in the lung and oxidative stress which have been implicated in tissue injury. In these studies, we analyzed the effects of N-acetylcysteine (NAC), an inhibitor of oxidative stress and inflammation on NM-induced lung injury, macrophage activation and bioenergetics. Treatment of rats with NAC (150 mg/kg, i.p., daily) beginning 30 min after administration of NM (0.125 mg/kg, i.t.) reduced histopathologic alterations in the lung including alveolar interstitial thickening, blood vessel hemorrhage, fibrin deposition, alveolar inflammation, and bronchiolization of alveolar walls within 3 d of exposure; damage to the alveolar-epithelial barrier, measured by bronchoalveolar lavage fluid protein and cells, was also reduced by NAC, along with oxidative stress as measured by heme oxygenase (HO)-1 and Ym-1 expression in the lung. Treatment of rats with NAC attenuated the accumulation of macrophages in the lung expressing proinflammatory genes including Ptgs2, Nos2, Il-6 and Il-12; macrophages expressing inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2 and tumor necrosis factor (TNF)α protein were also reduced in histologic sections. Conversely, NAC had no effect on macrophages expressing the anti-inflammatory proteins arginase-1 or mannose receptor, or on NM-induced increases in matrix metalloproteinase (MMP)-9 or proliferating cell nuclear antigen (PCNA), markers of tissue repair. Following NM exposure, lung macrophage basal and maximal glycolytic activity increased, while basal respiration decreased indicating greater reliance on glycolysis to generate ATP. NAC increased both glycolysis and oxidative phosphorylation. Additionally, in macrophages from both control and NM treated animals, NAC treatment resulted in increased S-nitrosylation of ATP synthase, protecting the enzyme from oxidative damage. Taken together, these data suggest that alterations in NM-induced macrophage activation and bioenergetics contribute to the efficacy of NAC in mitigating lung injury.

Functional roles of CD26/DPP4 in lipopolysaccharide-induced lung injury.

Acute respiratory distress syndrome (ARDS) is characterized by dysregulated inflammation and increased permeability of lung microvascular cells. CD26/dipeptidyl peptidase-4 (DPP4) is a type II membrane protein that is expressed in several cell types and mediates multiple pleiotropic effects. We previously reported that DPP4 inhibition by sitagliptin attenuates lipopolysaccharide (LPS)-induced lung injury in mice. The current study characterized the functional role of CD26/DPP4 expression in LPS-induced lung injury in mice, isolated alveolar macrophages, and cultured lung endothelial cells. In LPS-induced lung injury, inflammatory responses [bronchoalveolar lavage fluid (BALF) neutrophil numbers and several proinflammatory cytokine levels] were attenuated in Dpp4 knockout (Dpp4 KO) mice. However, multiple assays of alveolar capillary permeability were similar between the Dpp4 KO and wild-type mice. TNF-α and IL-6 production was suppressed in alveolar macrophages isolated from Dpp4 KO mice. In contrast, in cultured mouse lung microvascular endothelial cells (MLMVECs), reduction in CD26/DPP4 expression by siRNA resulted in greater ICAM-1 and IL-6 expression after LPS stimulation. Moreover, the LPS-induced vascular monolayer permeability in vitro was higher in MLMVECs treated with Dpp4 siRNA, suggesting that CD26/DPP4 plays a protective role in endothelial barrier function. In summary, this study demonstrated that genetic deficiency of Dpp4 attenuates inflammatory responses but not permeability in LPS-induced lung injury in mice, potentially through differential functional roles of CD26/DPP4 expression in resident cellular components of the lung. CD26/DPP4 may be a potential therapeutic target for ARDS and warrants further exploration to precisely identify the multiple functional effects of CD26/DPP4 in ARDS pathophysiology.NEW & NOTEWORTHY We aimed to clarify the functional roles of CD26/DPP4 in ARDS pathophysiology using Dpp4-deficient mice and siRNA reduction techniques in cultured lung cells. Our results suggest that CD26/DPP4 expression plays a proinflammatory role in alveolar macrophages while also playing a protective role in the endothelial barrier. Dpp4 genetic deficiency attenuates inflammatory responses but not permeability in LPS-induced lung injury in mice, potentially through differential roles of CD26/DPP4 expression in the resident cellular components of the lung.