Oxidative Stress In Lung Tissue Research Articles

Protective Effects of Tunisian Orange Co-Product Extract and Oleuropein-Hesperidin Combination on Bleomycin-Induced Pulmonary Fibrosis in Rats.

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial pneumonia with acute lung damage leading to the deterioration of lung function and increased mortality risk. In this study, we aimed to investigate the effects of the orange coproduct extract (OCE) and the combination of pure hesperidin and oleuropein (HO) on an experimental model of pulmonary fibrosis induced by bleomycin (BLM). Wistar rats were divided into 6 groups: the control group (G1), the BLM group (G2), 3 groups (G3, G4, G5) receiving a single dose of BLM combined with OCE extract at 100, 200 and 300 mg/kg and group 6 (G6) receiving a single dose of BLM combined with HO: both pure major phenolic compounds of OCE (hesperidin at 50 mg/kg) and olive leaves (oleuropein at 2.5 mg/kg). Oxidative stress in lung tissues was investigated using catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPX) assays and the measurement of malondialdehyde (MDA) and lactate dehydrogenase (LDH) levels. Treatment with OCE and HO were able to normalize the disturbance in oxidative markers' levels and showed a significant reduction in fibrosis score with no renal or hepatic toxic effects. In conclusion, OCE and HO exhibit antifibrotic effects on rat model of pulmonary fibrosis.

Bisdemethoxycurcumin alleviates LPS-induced acute lung injury via activating AMPKα pathway

ObjectiveInflammation and oxidative stress contribute to the pathogenesis of acute lung injury (ALI), and subsequently result in rapid deterioration in health. Considering the indispensable role of bisdemethoxycurcumin (BDMC) in inflammation and oxidative stress, the present study aims to examine the effect of BDMC on sepsis-related ALI.MethodsC57BL/6 mice were administered with BDMC (100 mg/kg) or an equal volume of vehicle, and then injected with lipopolysaccharides (LPS) to induce ALI. We assessed the parameters of lung injury, inflammatory response and oxidative stress in lung tissues. Consistently, the macrophages with or without BDMC treatment were exposed to LPS to verify the effect of BDMC in vitro.ResultsBDMC suppressed LPS-induced lung injury, inflammation and oxidative stress in vivo and in vitro. Mechanistically, BDMC increased the phosphorylation of AMPKα in response to LPS stimulation, and AMPK inhibition with Compound C almost completely blunted the protective effect of BDMC in LPS-treated mice and macrophages. Moreover, we demonstrated that BDMC activated AMPKα via the cAMP/Epac pathway.ConclusionOur study identifies the protective effect of BDMC against LPS-induced ALI, and the underlying mechanism may be related to the activation of cAMP/Epac/AMPKα signaling pathway.

Paroxetine protects against bleomycin-induced pulmonary fibrosis by blocking GRK2/Smad3 pathway.

G protein-coupled receptor kinase-2 (GRK2) is involved in TGF-β1-induced activation of lung fibroblasts, which could give rise to the pathogenesis of pulmonary fibrosis. Paroxetine (PRXT) serves as a selective GRK2 inhibitor which is widely used to treat anxiety and depression for several decades. However, whether PRXT could inhibit TGF-β1-induced activation of lung fibroblasts and combat bleomycin-induced pulmonary fibrosis remains unclear. Here, we investigated the effects of PRXT on pulmonary fibrosis in C57/BL6 caused by bleomycin as well as on the activation of murine primary lung fibroblasts stimulated with TGF-β1. The results demonstrated that PRXT markedly improved the pulmonary function and 21-day survival in bleomycin-induced mice. Meanwhile, PRXT significantly decreased collagen deposition, inflammation, and oxidative stress in lung tissues from bleomycin-induced mice. Furthermore, we found that PRXT could inhibit the protein and mRNA expression of GRK2 and Smad3 in lung tissues from bleomycin-induced mice. In vitro experiments also PRXT could inhibit cell activation and collagen synthesis in a concentration-dependent manner in TGF-β1-induced lung fibroblasts. In addition, we found that Smad3 overexpression by adenovirus transfection could offset anti-fibrotic and antioxidative effects from PRXT in TGF-β1-induced lung fibroblasts, which showed no effects on the protein expression of GRK2. In conclusion, PRXT mediates the inhibition of GRK2, which further blocks the transcription of Smad3 in TGF-β1-induced lung fibroblasts, providing an attractive therapeutic target for pulmonary fibrosis.

Plumbagin alleviates obesity-related asthma: Targeting inflammation, oxidative stress, and the AMPK pathway.

Obesity-related asthma, a specific type of asthma, tends to have more severe symptoms and more frequent exacerbations, and it is insensitive to standard medications. Plumbagin (PLB) has many positive effects on human health. However, it remains unclear whether PLB protects against obesity-related asthma. The study investigated the effect of PLB on obesity-related asthma. Four-week-old male C57BL6/J mice were fed either standard-chow diet or high-fat diet (HFD). The mice were sensitized to 100 μg ovalbumin (OVA) once a week and intraperitoneally injected with 1 mg/kg PLB once daily from Week 10 to 11 and then challenged with 10 μg OVA twice a day on Week 12. The lung tissue and bronchoalveolar lavage fluid (BALF) were collected 48 h after the first OVA challenge. HFD enhanced inflammatory cell infiltration within the airways and increased total inflammatory cell and eosinophil counts, levels of eosinophil-related inflammatory cytokines, including interleukin-4 (IL-4), IL-5, and eotaxin in BALF, and oxidative stress in the lung tissues of asthmatic mice. PLB reduced inflammatory cell infiltration in the airway walls, levels of eosinophil-related inflammatory cytokines in BALF, and oxidative stress in lung tissues of obese asthmatic mice. In addition, PLB restored HFD-induced decreases in adenosine monophosphate-activated protein kinase (AMPK) phosphorylation. The study suggested that HFD exacerbated inflammation and oxidative stress, while PLB probably alleviated inflammation and oxidative stress and activated AMPK pathway to attenuate obesity-associated asthma. Thus, PLB likely had the potential to treat obesity-related asthma.

Limonin, a novel AMPK activator, protects against LPS-induced acute lung injury

AMP-activated protein kinase (AMPK) activation plays crucial roles in the treatment of many oxidative stress- and inflammation-induced diseases, including acute lung injury (ALI). Limonin is a naturally occurring tetracyclic triterpenoid extracted from the plants of Rutaceae and Meliaceae. Limonin also serves as an AMPK activator with anti-inflammatory and anti-oxidation effects. However, the potential beneficial effects of limonin on ALI and the possible mechanisms have never been disclosed till now. Here, the effects of limonin on lipopolysaccharide (LPS)-induced ALI in C57 BL/6 mice, plus bone marrow-derived macrophages (BMDM) stimulated with LPS to induce in vitro ALI model were investigated. Limonin significantly improved pulmonary function and alleviated lung pathological injury in LPS-induced mice. Meanwhile, limonin also markedly decreased inflammation and oxidative stress in lung tissues from LPS-treated mice. In vitro experiments also unveiled that limonin could decrease inflammation and oxidative stress in LPS-induced BMDM in a concentration-dependent manner. Mechanically, limonin could promote the activation of AMPKα and upregulate the expression of nuclear factor erythroid 2-related factor 2 (NRF2) in lung tissues and BMDM. Pharmacological inhibition of AMPKα by Compound C or AMPKα knockout could abolish the pulmonary protection from limonin during ALI. In conclusion, limonin mediates the activation of AMPKα/NRF2 pathway, providing an attractive therapeutic target for ALI in the future.

The efficacy of caffeic acid phenethyl ester (CAPE) in the protection against radiation-induced oxidative stress in the lung as a distant organ

ObjectiveThe objective of this study is to measure the parameters of oxidative stress in the lungs of rats exposed to cranial radiation and to assess the potential radioprotective effectiveness of Caffeic acid phenethyl ester (CAPE). MethodsIn this study, 32 Sprague-Dawley rats were divided into four equal groups. The sham group received only non-radiation sham irradiation, the control group received dimethyl sulfoxide for ten days (1 ml/kg/day), the radiation group received a single dose of 5 Gy total cranial radiation and saline solution (1 ml/kg/day) for ten days, and the radiation plus CAPE group received a single dose of 5 Gy total cranial radiation and CAPE at a dose of 80 mg/kg/day, dissolved in 1 ml/kg/day of dimethyl sulfoxide for ten days. Oxidative and antioxidant parameters were measured in the lung tissue of rats. ResultsThe oxidative parameters, total oxidant status, oxidative stress index, and lipid hydroperoxide in the radiation group were significantly higher compared to the radiation plus CAPE group (p < 0.0001 for all). On the other hand, the antioxidative parameter, total antioxidant status, was significantly higher in the radiation plus CAPE group than in the other groups (p < 0.0001 for all). The levels of paraoxonase were also significantly higher in the radiation plus CAPE group compared to the other groups (p < 0.0001 for all). Ceruloplasmin was found to be higher in the control group than in the radiation group (p = 0.001). Additionally, arylesterase levels were significantly lower in the radiation group than in the other groups (p = 0.014, p = 0.002, p = 0.011). Thiol levels were lower in the radiation group compared to the sham and radiation plus CAPE groups (p = 0.013 and p = 0.004, respectively). ConclusionsThis study suggests that cranial radiation induces oxidative stress in lung tissue, and CAPE provides protection against oxidative damage by reducing oxidant parameters and increasing antioxidant parameters. These findings highlight the potential radioprotective effects of CAPE and its potential use as a therapeutic agent for mitigating the harmful effects of radiation-induced oxidative stress.

Glutamine inhibits inflammation, oxidative stress, and apoptosis and ameliorates hyperoxic lung injury.

Glutamine (Gln) is the most widely acting and abundant amino acid in the body and has anti-inflammatory properties, regulates body metabolism, and improves immune function. However, the mechanism of Gln's effect on hyperoxic lung injury in neonatal rats is unclear. Therefore, this work focused on examining Gln's function in lung injury of newborn rats mediated by hyperoxia and the underlying mechanism. We examined body mass and ratio of wet-to-dry lung tissue weights of neonatal rats. Hematoxylin and eosin (HE) staining was performed to examine histopathological alterations of lung tissues. In addition, enzyme-linked immunoassay (ELISA) was conducted to measure pro-inflammatory cytokine levels within bronchoalveolar lavage fluid (BALF). Apoptosis of lung tissues was observed using TUNEL assay. Western blotting was performed for detecting endoplasmic reticulum stress (ERS)-associated protein levels. The results showed that Gln promoted body weight gain, significantly reduced pathological damage and oxidative stress in lung tissue, and improved lung function in neonatal rats. Gln reduced pro-inflammatory cytokine release as well as inflammatory cell production in BALF and inhibited apoptosis in lung tissue cells. Furthermore, we found that Gln could downregulate ERS-associated protein levels (GRP78, Caspase-12, CHOP) and inhibit c-Jun N-terminal kinase (JNK) and inositol-requiring enzyme 1 alpha (IRE1α) phosphorylation. These results in an animal model of bronchopulmonary dysplasia (BPD) suggest that Gln may have a therapeutic effect on BPD by reducing lung inflammation, oxidative stress, and apoptosis and improving lung function; its mechanism of action may be related to the inhibition of the IRE1α/JNK pathway.

Soy isoflavone reduces LPS-induced acute lung injury via increasing aquaporin 1 and aquaporin 5 in rats.

Acute lung injury (ALI) followed with severe inflammation and oxidative stress. Anti-inflammatory and antioxidant are the properties of aquaporin 1 (AQP1) and aquaporin 5 (AQP5). The goal of this study was to see if soy isoflavone can diminish lipopolysaccharide (LPS)-induced ALI and the underling mechanism. LPS-induced ALI was given to Sprague-Dawley rats 14 days following oophorectomy. One hour before the LPS challenge, estradiol (1 mg/kg) was administered subcutaneously as positive control and soy isoflavone was intragastric administration for 14 days prior to LPS challenge with different doses. Six hours after LPS challenge, the pulmonary edema, pathophysiology, inflammation, and the oxidative stress in lung tissues of rats were discovered. We found that soy isoflavone can reduce pulmonary edema and the lung pathology in a dose-dependent manner. Furthermore, tumor necrosis factor-alpha, interleukin-1β, and interleukin-6 were decreased in rats treated with soy isoflavone. Meanwhile, soy isoflavone reduced pulmonary oxidative stress by decreasing malondialdehyde levels, while increasing superoxide dismutase levels in lung tissues in a dose-dependent manner. Mechanically, we found that the mRNA and protein level of AQP1 and AOP5 were increased in lung tissues of rats treated with soy isoflavone compared the LPS-treated rats. Thus, soy isoflavone alleviates LPS-induced ALI through inducing AQP1 and AQP5.

ROS-sensitive Crocin-loaded chitosan microspheres for lung targeting and attenuation of radiation-induced lung injury

Radiation-induced lung injury (RILI) is one of the major complications in patients exposed to accidental radiation and radiotherapy for thoracic malignancies. However, there is no reliable radioprotector for effective clinical treatment of RILI so far. Herein, a novel Crocin-loaded chitosan microsphere is developed for lung targeting and attenuation of RILI. The chitosan microspheres are modified with 4-carboxyphenylboronic acid and loaded with the natural antioxidant Crocin-I to give the drug-loaded microspheres (~10 μm). The microspheres possess good biocompatibility in vivo and in vitro. In a mouse model, they exhibit effective passive targeting performance and a long retention time in the lung after intravenous administration. Furthermore, they improve the radioprotective effect of Crocin-I for the treatment of RILI by reducing the level of inflammatory cytokines in bronchoalveolar lavage fluid and by regulating oxidative stress in lung tissues. The targeted agents significantly improved the bioavailability and radioprotection of Crocin-I by the outstanding passive targeting effect. This work may provide a promising strategy for efficient radioprotection on RILI using passive lung targeting microspheres.

Nrf2 regulates the expression of NOX1 in TNF-α-induced A549 cells

Acute lung injury causes severe inflammation and oxidative stress in lung tissues. In this study, we analyzed the potential regulatory role of nuclear factor erythroid-2-related factor 2 (Nrf2) on NADPH oxidase 1 (NOX1) in tumor necrosis factor-α (TNF-α)-induced inflammation and oxidative stress in human type II alveolar epithelial cells. In this study, A549 cells were transfected with Nrf2 siRNA and overexpression vectors for 6 h before being induced by TNF-α for 24 h. TNF-α upregulated the expression of NOX1 and Nrf2 in A549 cells. Furthermore, overexpression of Nrf2 could reduce TNF-α-induced NF-κB mRNA and protein expression after transfection with the Nrf2 siRNA vector, and the levels of IL-6, IL-8, ROS, and malondialdehyde (MDA) in TNF-α-induced A549 cells increased, while the level of total antioxidation capability (T-AOC) decreased. On the other hand, the overexpression of Nrf2 decreased the levels of IL-6, IL-8, ROS, and MDA, while increasing T-AOC. The mRNA and protein levels of NOX1 were dramatically increased by TNF-α, while those changes were notably suppressed by Nrf2 overexpression. Further studies demonstrated that Nrf2 suppressed NOX1 transcription by binding to the -1199 to -1189 bp (ATTACACAGCA) region of the NOX1 promoter in TNF-α-stimulated A549 cells. Our study suggests that Nrf2 may bind to and regulate NOX1 expression to antagonize TNF-α-induced inflammatory reaction and oxidative stress in A549 cells.

Attenuation of the Severity of Acute Respiratory Distress Syndrome by Pomiferin through Blocking Inflammation and Oxidative Stress in an AKT/Foxo1 Pathway-Dependent Manner.

Acute respiratory distress syndrome (ARDS) gives rise to uncontrolled inflammatory response and oxidative stress, causing very high mortality globally. Pomiferin is a kind of prenylated isoflavonoid extracted from Maclura pomifera, owning anti-inflammatory and antioxidant properties. However, the functions and possible mechanisms of pomiferin in lipopolysaccharide- (LPS-) induced ARDS remain unknown. C57BL/6 mice were injected with LPS (5 mg/kg) intratracheally to induce an in vivo ARDS model while RAW264.7 macrophages were stimulated with LPS (100 ng/ml) to induce an in vitro model. Our data demonstrated that pomiferin (20 mg/kg) significantly improved pulmonary function and lung pathological injury in mice with ARDS, apart from increasing survival rate. Meanwhile, pomiferin treatment also inhibited LPS-induced inflammation as well as oxidative stress in lung tissues. LPS stimulation significantly activated AKT/Foxo1 signal pathway in lung tissues, which could be reversed after pomiferin treatment. In vitro experiments further showed that 10, 20, and 50 μM of pomiferin could enhance cell viability of RAW264.7 macrophages stimulated with LPS. What is more, 3-deoxysappanchalcone (3-DE), one AKT agonist, was used to active AKT in RAW264.7 macrophages. The results further showed that 3-DE could abolish pomiferin-elicited protection in LPS-treated RAW264.7 macrophages, evidenced by activated inflammation and oxidative stress. Taken together, our study showed that pomiferin could exert an ARDS-protective effect by blocking the AKT/Foxo1 signal pathway to inhibit LPS-induced inflammatory response and oxidative injury, which may serve as a potential candidate for the treatment of ARDS in the future.

Effects of Corilagin on Lipopolysaccharide-Induced Acute Lung Injury via Regulation of NADPH Oxidase 2 and ERK/NF-κB Signaling Pathways in a Mouse Model.

Simple SummaryCorilagin has anti-inflammatory and antioxidant properties. Acute lung injury is a life-threatening disease. This investigated the protective effects and mechanisms of corilagin on acute lung injury. The results show that corilagin can reduce acute lung injury via attenuation of pro-inflammatory mediators and oxidative stress. Corilagin has potential utility as a therapeutic agent for the treatment of this life-threatening respiratory disease.Acute lung injury (ALI) and acute respiratory distress syndrome are clinically life-threatening diseases. Corilagin, a major polyphenolic compound obtained from the herb Phyllanthus urinaria, has anti-inflammatory and antioxidant properties, and in this study, we sought to evaluate the protective effects and mechanisms of corilagin on lipopolysaccharide (LPS)-induced ALI in mice. ALI was induced in the mice by the intratracheal administration of LPS, and following 30 min of LPS challenge, corilagin (5 and 10 mg/kg body weight) was administered intraperitoneally. At 6 h post-LPS administration, lung tissues were collected for analysis. Corilagin treatment significantly attenuated inflammatory cell infiltration, the production of pro-inflammatory cytokines TNF-α, IL-6, and IL-1β, and oxidative stress in lung tissues. In addition, corilagin inhibited the LPS-induced expression of NOX2, ERK, and NF-κB. Corilagin has anti-oxidative and anti-inflammatory effects, and can effectively reduce ALI via attenuation of the NOX2 and ERK/NF-κB signaling pathways.

Naringenin Improves Ovalbumin-Induced Allergic Asthma in Rats through Antioxidant and Anti-Inflammatory Effects

Asthma is a chronic disease with eosinophilic inflammation and oxidative damages leading to airway obstruction. Naringenin is a phytochemical possessing strong antioxidant and anti-inflammatory activities against chronic destructive conditions. The current study is devoted to evaluating naringenin's effects on the attenuation of inflammation and oxidative stress in lung tissue in a rat model of ovalbumin-induced asthma. Male Wistar rats were allocated to five groups of six: normal control (NC, receiving 1 ml/day of normal saline, orally), asthmatic (AS, receiving ovalbumin (1 mg/mL), and alum (1 mg/mL in saline) on days 0 and 14. Then, on days 21, 22, and 23, they were sensitized with the inhalation of ovalbumin), AS treated with dexamethasone (AS, 1 mg/kg/day, orally) [AS + D1], AS treated with naringenin (20 mg/kg/day, orally) [AS + N20], and AS treated with naringenin (40 mg/kg/day, orally) [AS + N40]. All the groups received associated drugs/agents for 28 days. Finally, bronchoalveolar lavage fluid (BALF) and lung tissue samples were taken off from the animals. The eosinophil count in BALF and malondialdehyde (MDA), glutathione (GSH), interleukin-13 and -4 (IL-13 and IL-4) levels were measured. Besides, the expression of urocortin (UCN) and surfactant protein-D (SP-D) were evaluated in the lung tissue using immunohistochemistry (IHC) and western blotting methods, respectively. Hematoxylin and eosin (H&E) staining were utilized to conduct histopathological analysis. Naringenin treatment significantly reduced MDA, remarkably increased GSH, and meaningfully reduced IL-4 and IL-13 levels in lung tissue. The count of eosinophils in the BALF of AS + N20 and AS + N40 was significantly reduced in comparison with the AS group. The UCN and SP-D protein levels were significantly decreased in the AS + N20 and AS + N40 groups compared to the AS group, using the IHC and western blot methods, respectively. Histopathological analysis data also confirm the results. Naringenin improves the symptoms of allergic asthma through antioxidant and anti-inflammatory effects.

MicroRNA-363-3p/sphingosine-1-phosphate receptor 1 axis inhibits sepsis-induced acute lung injury via the inactivation of nuclear factor kappa-B ligand signaling.

Infection-associated inflammation and coagulation are critical pathologies in sepsis-induced acute lung injury (ALI). This study aimed to investigate the effects of microRNA-363-3p (miR-363-3p) on sepsis-induced ALI and explore the underlying mechanisms. A cecal ligation and puncture-induced septic mouse model was established. The results of this study suggested that miR-363-3p was highly expressed in lung tissues of septic mice. Knockdown of miR-363-3p attenuated sepsis-induced histopathological damage, the inflammation response and oxidative stress in lung tissues. Furthermore, knockdown of miR-363-3p reduced the formation of platelet-derived microparticles and thrombin generation in blood samples of septic mice. Downregulation of miR-363-3p suppressed sphingosine-1-phosphate receptor 1 (S1PR1) expression in lung tissues and subsequently inactivated the nuclear factor kappa-B ligand (NF-κB) signaling. A luciferase reporter assay confirmed that miR-363-3p directly targeted the 3’-untranslated region of the mouse S1pr1 mRNA. Collectively, our study suggests that inactivation of NF-κB signaling is involved in the miR-363-3p/S1PR1 axis-mediated protective effect on septic ALI.

Ginsenoside Rg3 Alleviates Rotenone-induced Lung Injury in Mice by Its Anti-oxidative Properties

Objectives: Acute lung injury is commonly found in patients with insecticide poisoning and the pathogenesis is related to oxidative stress. Ginsenoside Rg3, one of the main constituents of Panax ginseng C.A. Meyer, shows an anti-oxidative activity. The aim of this study was to evaluate whether ginsenoside Rg3 can alleviate lung injury induced by rotenone in mice.&#x0D; Methods: C57BL/6J male mice were divided into five groups (n=11). The mice in ginsenoside Rg3 groups were treated with ginsenoside Rg3 at dose of 5, 10 or 20 mg/kg. Except for the control group, mice were challenged intragastrically with rotenone at dose of 30 mg/kg, once a day for 6 weeks. Subsequently, the lung tissues of mice were collected. The effect of ginsenoside Rg3 on rotenone-induced lung injury was observed by hematoxylin and eosin staining. The oxidative stress in lung tissues were also examined.&#x0D; Results: Rotenone induced substantial hemorrhage, alveolar wall thickness and neutrophils infiltration. These structural damages were attenuated significantly by ginsenoside Rg3 treatment. The lung injury induced by rotenone was associated with oxidative stress in lung tissues of mice. Compared with the control group, rotenone exposure resulted in the increase of malondialdehyde (MDA), the decreases of the activities of superoxide dismutase (SOD), glutathione peroxidase (GHS-Px), and the glutathione (GSH) content. Nevertheless, ginsenoside Rg3 treatment not only reduced MDA production but also increased the activities of SOD, GSH-Px, and the content of GSH in lung tissue of mice.&#x0D; Conclusion: Taken together, this study demonstrated that ginsenoside Rg3 has potential to ameliorate rotenone-induced lung injury and the mechanism of action of ginsenoside Rg3 is mediated by its anti-oxidative properties.&#x0D; &#x0D;

Mucin1 relieves acute lung injury by inhibiting inflammation and oxidative stress.

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a kind of diffuse inflammatory injury caused by various factors, characterized by respiratory distress and progressive hypoxemia. It is a common clinical critical illness. The aim of this study was to investigate the effect and mechanism of the Mucin1 (MUC1) gene and its recombinant protein on lipopolysaccharide (LPS)-induced ALI/ARDS. We cultured human alveolar epithelial cell line (BEAS-2B) and used MUC1 overexpression lentivirus to detect the effect of MUC1 gene on BEAS-2B cells. In addition, we used LPS to induce ALI/ARDS in C57/BL6 mice and use hematoxylin and eosin (H&E) staining to verify the effect of their modeling. Recombinant MUC1 protein was injected subcutaneously into mice. We examined the effect of MUC1 on ALI/ARDS in mice by detecting the expression of inflammatory factors and oxidative stress molecules in mouse lung tissue, bronchoalveolar lavage fluid (BALF) and serum. Overexpression of MUC1 effectively ameliorated LPS-induced damage to BEAS-2B cells. Results of H&E staining indicate that LPS successfully induced ALI/ARDS in mice and MUC1 attenuated lung injury. MUC1 also reduced the expression of inflammatory factors (IL-1β, TNF-α, IL-6 and IL-8) and oxidative stress levels in mice. In addition, LPS results in an increase in the activity of the TLR4/NF-κB signaling pathway in mice, whereas MUC1 decreased the expression of the TLR4/NF-κB signaling pathway. MUC1 inhibited the activity of TLR4/NF-κB signaling pathway and reduced the level of inflammation and oxidative stress in lung tissue of ALI mice.

MicroRNA-139-5p improves sepsis-induced lung injury by targeting Rho-kinase1.

Sepsis-induced acute lung injury (ALI) is an inflammatory process that involves inflammatory cytokine production and cell apoptosis. In the present study, the regulatory role of microRNA (miR)-139-5p in sepsis-induced ALI was investigated using a murine model of cecal ligation puncture (CLP) and an in vitro model using lipopolysaccharide (LPS)-induced normal human bronchial epithelial cells (NHBEs). Sepsis-induced pathological changes in the lungs of ALI mice were detected using hematoxylin and eosin staining. Lung water content was determined, and the expression of proinflammatory cytokines in the bronchoalveolar lavage fluid and serum of sepsis-induced ALI mice were quantified using ELISA. The levels of oxidative stress in lung tissues were determined using commercial kits. The degree of apoptosis was determined using a TUNEL assay. The expression levels of miR-139-5p and Rho-kinase 1 (ROCK1) were determined using reverse transcription-quantitative PCR and western blot analyses. A dual-luciferase reporter assay was used to confirm the direct targeting of ROCK1 by miR-139-5p. NHBEs were co-transfected with vectors expressing ROCK1 (or empty vector) and miR-139-5p mimics or control mimics prior to LPS treatment. The transcriptional activity of caspase-3, the ratio of apoptotic cells, the expression levels of mucin 5AC, mucin 1, TNF-α, IL-1β, IL-6, NLR family pyrin domain containing 3, apoptosis-associated speck-like protein containing a CARD and caspase-1 were evaluated. Compared with the normal group, mice that underwent CLP exhibited abnormal lung morphology, enhanced production of TNF-α, IL-1β and IL-6, increased reactive oxygen species (ROS), malondialdehyde and lactate dehydrogenase levels, an increased proportion of apoptotic cells and increased ROCK1 expression. Superoxide dismutase, glutathione peroxidase and miR-139-5p levels were decreased following CLP. In the NHBEs, stimulation with LPS caused a marked increase in inflammatory cytokine levels and apoptosis compared with the untreated cells. Overexpression of miR-139-5p attenuated cell apoptosis and inflammation. Overexpression of ROCK1 in NHBEs restored the ROS levels and proinflammatory cytokine production inhibited by miR-139-5p. In conclusion, miR-139-5p alleviated sepsis-induced ALI via suppression of its downstream target, ROCK1, suggesting that miR-139-5p may hold promise in the treatment of sepsis-induced ALI.

Mitochondrial-Targeting Antioxidant SS-31 Suppresses Airway Inflammation and Oxidative Stress Induced by Cigarette Smoke.

This study investigated whether the mitochondrial-targeted peptide SS-31 can protect against cigarette smoke- (CS-) induced airway inflammation and oxidative stress in vitro and in vivo. Mice were exposed to CS for 4 weeks to establish a CS-induced airway inflammation model, and those in the experimental group were pretreated with SS-31 1 h before CS exposure. Pathologic changes and oxidative stress in lung tissue, inflammatory cell counts, and proinflammatory cytokine levels in bronchoalveolar lavage fluid (BALF) were examined. The mechanistic basis for the effects of SS-31 on CS extract- (CSE-) induced airway inflammation and oxidative stress was investigated using BEAS-2B bronchial epithelial cells and by RNA sequencing and western blot analysis of lung tissues. SS-31 attenuated CS-induced inflammatory injury of the airway and reduced total cell, neutrophil, and macrophage counts and tumor necrosis factor- (TNF-) α, interleukin- (IL-) 6, and matrix metalloproteinase (MMP) 9 levels in BALF. SS-31 also attenuated CS-induced oxidative stress by decreasing malondialdehyde (MDA) and myeloperoxidase (MPO) activities and increasing that of superoxide dismutase (SOD). It also reversed CS-induced changes in the expression of mitochondrial fission protein (MFF) and optic atrophy (OPA) 1 and reduced the amount of cytochrome c released into the cytosol. Pretreatment with SS-31 normalized TNF-α, IL-6, and MMP9 expression, MDA and SOD activities, and ROS generation in CSE-treated BEAS-2B cells and reversed the changes in MFF and OPA1 expression. RNA sequencing and western blot analysis showed that SS-31 inhibited CS-induced activation of the mitogen-activated protein kinase (MAPK) signaling pathway in vitro and in vivo. Thus, SS-31 alleviates CS-induced airway inflammation and oxidative stress via modulation of mitochondrial function and regulation of MAPK signaling and thus has therapeutic potential for the treatment of airway disorders caused by smoking.

Endogenous Hydrogen Sulfide Is an Important Factor in Maintaining Arterial Oxygen Saturation.

The gasotransmitter H2S is involved in various physiological and pathophysiological processes. The aim of this study was to investigate the physiological functions of H2S in the lungs. In the model of mouse with genetic deficiency in a H2S natural synthesis enzyme cystathionine-γ-lyase (CSE), we found that arterial oxygen saturation (SaO2) was decreased compared with wild type mice. Hypoxyprobe test showed that mild hypoxia occurred in the tissues of heart, lungs and kidneys in Cse -/- mice. H2S donor GYY4137 treatment increased SaO2 and ameliorated hypoxia state in cardiac and renal tissues. Further, we revealed that lung blood perfusion and airway responsiveness were not linked to reduced SaO2 level. Lung injury was found in Cse -/- mice as evidenced by alveolar wall thickening, diffuse interstitial edema and leukocyte infiltration in pulmonary tissues. IL-8, IL-1β, and TNF-α levels were markedly increased and oxidative stress levels were also significantly higher with increased levels of the pro-oxidative biomarker, MDA, decreased levels of the anti-oxidative biomarkers, T-AOC and GSH/GSSG, and reduced superoxide dismutase (SOD) activity in lung tissues of Cse -/- mice compared with those of wild type mice. GYY4137 treatment ameliorated lung injury and suppressed inflammatory state and oxidative stress in lung tissues of Cse -/- mice. A decrease in SaO2 was found in normal mice under hypoxia. These mice displayed lung injury as evidenced by alveolar wall thickening, interstitial edema and leukocyte infiltration. Increased levels of inflammatory cytokines and oxidative stress were also found in lung tissues of the mice with hypoxia insult. GYY4137 treatment increased SaO2 and ameliorated lung injury, inflammation and oxidative stress. Our data indicate that endogenous H2S is an important factor in maintaining normal SaO2 by preventing oxidative stress and inflammation in the lungs.

Catalpol Protects Against Pulmonary Fibrosis Through Inhibiting TGF-β1/Smad3 and Wnt/β-Catenin Signaling Pathways.

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease characterized by fibroblast proliferation and extracellular matrix remodeling; however, the molecular mechanisms underlying its occurrence and development are not yet fully understood. Despite it having a variety of beneficial pharmacological activities, the effects of catalpol (CAT), which is extracted from Rehmannia glutinosa, in IPF are not known. In this study, the differentially expressed genes, proteins, and pathways of IPF in the Gene Expression Omnibus database were analyzed, and CAT was molecularly docked with the corresponding key proteins to screen its pharmacological targets, which were then verified using an animal model. The results show that collagen metabolism imbalance, inflammatory response, and epithelial-mesenchymal transition (EMT) are the core processes in IPF, and the TGF-β1/Smad3 and Wnt/β-catenin pathways are the key signaling pathways for the development of pulmonary fibrosis. Our results also suggest that CAT binds to TGF-βR1, Smad3, Wnt3a, and GSK-3β through hydrogen bonds, van der Waals bonds, and other interactions to downregulate the expression and phosphorylation of Smad3, Wnt3a, GSK-3β, and β-catenin, inhibit the expression of cytokines, and reduce the degree of oxidative stress in lung tissue. Furthermore, CAT can inhibit the EMT process and collagen remodeling by downregulating fibrotic biomarkers and promoting the expression of epithelial cadherin. This study elucidates several key processes and signaling pathways involved in the development of IPF, and suggests the potential value of CAT in the treatment of IPF.