MicroRNA-34a Suppresses Autophagy in Alveolar Type II Epithelial Cells in Acute Lung Injury by Inhibiting FoxO3 Expression

Excessive autophagic activity of alveolar type II epithelial (AT-II) cells is one of the main causes of acute lung injury (ALI); however, the underlying molecular mechanism remains to be determined. The microRNAs (miRNAs) are involved with autophagy in many diseases. The objective of this study was therefore to investigate the relationship between the miRNA expression and the autophagic activity of the AT-II cells in the pathogenesis of ALI and its molecular mechanism. A mouse model of ALI and AT-II cell injury was induced using lipopolysaccharide (LPS) in vivo and in vitro, and the expression of miR-34a and the autophagy-related proteins LC3 II/I and p62 were determined. Moreover, the autophagic activity was investigated after miR-34a overexpression and inhibition. The effects of miR-34a on its target gene, FoxO3, in regulating autophagic activity in AT-II cells were also determined. LPS induced autophagic activity and increased the expression of miR-34a in lung tissues and in AT-II cells. The in vitro results showed that the upregulation of miR-34a suppressed, whereas the inhibition of miR-34a promoted, autophagy in AT-II cells. Moreover, miR-34a could directly bind to the 3′-untranslated region of the autophagy-related gene, FoxO3, to decrease its expression. In addition, the knockdown of FoxO3 expression inhibited the autophagic activity in AT-II cells. Together, this study suggested that miR-34a might suppress the excessive autophagic activity in AT-II cells via targeting FoxO3 to reduce the damage of LPS-induced ALI.     

Tetrahydrocoptisine Protects Rats from LPS-Induced Acute Lung Injury

Recent studies show that nuclear factor-kappa B (NF-κB) signaling pathway plays a key role in contributing to the development of lipopolysaccharide (LPS)-induced acute lung injury (ALI). Tetrahydrocoptisine is one of the main active components of Chelidonium majus L. and has been described to be effective in suppressing inflammation. The aim of the present study is to evaluate the protective effect of tetrahydrocoptisine on LPS-induced ALI in rats and clarify its underlying mechanisms of action. We found that in vivo pretreatment with tetrahydrocoptisine to rats 30 min before inducing ALI by LPS markedly decreased the mortality rate, lung wet weight to dry weight ratio, and ameliorated lung pathological changes. Meanwhile, tetrahydrocoptisine significantly inhibited the increase of the amounts of inflammatory cells, total protein content, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) secretion in the bronchoalveolar lavage fluids (BALFs). Furthermore, tetrahydrocoptisine inhibited myeloperoxidase (MPO) accumulation in lung tissue and alleviated TNF-α and IL-6 production in serum. Additionally, immunohistochemistry showed that tetrahydrocoptisine efficiently reduced nuclear factor-kappa B (NF-κB) activation by inhibiting the translocation of NF-κBp65. In conclusion, our results demonstrate that tetrahydrocoptisine possesses a protective effect on LPS-induced ALI through inhibiting of NF-κB signaling pathways, which may involve the inhibition of pulmonary inflammatory process.     

Bakuchiol Protects Against Acute Lung Injury in Septic Mice

Sepsis is a systemic inflammatory reaction that may lead to multiple organ damage and acute lung injury (ALI). Bakuchiol (Bak) has been reported to confer protection against inflammation and oxidative stress. However, its effect on sepsis-induced acute lung injury remains unclear. In the present study, male C57BL/6 mice were subjected to cecal ligation and puncture (CLP), and Bak (15, 30, 60 mg/kg) was administered intragastrically after 0 and 3 h of surgery. Lung water content was detected. Pathologic changes in lung tissues were evaluated via hematoxylin and eosin (H&E) staining. The levels of myeloperoxidase (MPO), IL-1β, IL-6, and TNF-α were evaluated using ELISA. In addition, expression levels of phosphorylated (p)-IκB, ICAM-1, HMGB1, nitrotyrosine (3-NT), claudin-1, and VE-cadherin were detected using Western blot. Further, IL-1β expression was evaluated using immunofluorescence. SOD activity, contents of MDA, and 8-OHdG were detected to determine the level of oxidative stress. Our results suggested that Bak (60 mg/kg) treatment significantly attenuated pathologic changes and edema in lung tissues and attenuated inflammation and oxidative stress in the lung following sepsis. Additionally, Bak treatment alleviated sepsis-induced lung endothelial barrier disruption. In conclusion, Bak treatment attenuates ALI following sepsis by suppressing inflammation, oxidative stress, and endothelial barrier disruption. Our study indicates that Bak is a potential candidate to treat sepsis-induced ALI.     

Artesunate Protects LPS-Induced Acute Lung Injury by Inhibiting TLR4 Expression and Inducing Nrf2 Activation

Artesunate, a derivative of artemisinin, has been reported to have anti-inflammatory property. However, few studies showed the protective effects of artesunate on lung injury. In this study, we aimed to investigate the effects of artesunate on LPS-induced lung injury in mice. The mice were treated with artesunate 1 h before or after LPS treatment. The effects of artesunate on lung MPO activity and malondialdehyde (MDA) content were detected. The lung wet/dry radio and the numbers of inflammatory cells in BALF were also measured. ELISA was used to evaluate the levels of TNF-α, IL-1β, and IL-6 in BALF. Western blot analysis was adapted to detect TLR4 and Nrf2 signaling pathways. The results showed that artesunate protected against LPS-induced ALI by decreasing the numbers of inflammatory cells, lung edema, MPO activity, and MDA content. Furthermore, artesunate significantly inhibited the levels of TNF-α, IL-1β, and IL-6. Artesunate also inhibited LPS-induced IL-6 and IL-8 production in the A549 cells. In addition, artesunate dose-dependently suppressed LPS-induced TLR4 expression and NF-κB activation. The expression of Nrf2 and HO-1 were also up-regulated by artesunate. The data suggest that artesunate possesses anti-inflammatory and anti-oxidant properties against LPS-induced ALI via inhibiting TLR4 signaling pathway and activating Nrf2 signaling pathway.     

Ameliorative Effects of Oleuropein on Lipopolysaccharide-Induced Acute Lung Injury Model in Rats

Inflammation - Acute lung injury (ALI) is one of the most common causes of death in diseases with septic shock. Oleuropein, one of the important components of olive leaf, has antioxidant and...     

Kindlin-2 Mediates Lipopolysaccharide-Induced Acute Lung Injury Partially via Pyroptosis in Mice

Inflammation - Acute lung injury (ALI) is characteristic of the wholesale destruction of the lung endothelial barrier, which results in protein-rich lung edema, influx of pro-inflammatory...     

Selenium-Containing Compound Ameliorates Lipopolysaccharide-Induced Acute Lung Injury via Regulating the MAPK/AP-1 Pathway

Inflammation - Abstract—Acute lung injury (ALI) is characterized by a series of inflammatory reactions and serves as the main cause of mortality in intensive care unit patients. Although...     

Artesunate Protects Against Sepsis-Induced Lung Injury Via Heme Oxygenase-1 Modulation

Artesunate, a derivative of artemisinin, has anti-inflammatory properties and exerts protective roles in sepsis. Heme oxygense-1 (HO-1) inhibits the inflammatory response through reduction of proinflammatory cytokines and leukocyte influx into tissues. The present study investigated the effects of artesunate on HO-1 and septic lung injury. Cecal ligation and puncture (CLP) was employed to induce septic lung injury. Mice pretreated with artesunate (AS) (15 mg/kg) exhibited decreased sepsis-induced mortality and lung injury and alleviated lung pathological changes and neutrophil infiltration. In addition, AS lowered the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the serum and bronchoalveolar lavage fluid (BALF) and inhibited cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase isoform (iNOS) expression and NF-κB activation in lung tissue. In addition, AS enhanced NF-E2-related factor-2 (Nrf2) activation and HO-1 expression and enzymatic activity in lung tissue. However, the protective effects of AS on sepsis-induced lung injury were eliminated by ZnPP IX, an HO-1 competitive inhibitor. Therefore, AS plays protective roles in septic lung injury related to the upregulation of HO-1. These findings suggest an effective and applicable treatment to sepsis-induced lung injury and provide new insights into the molecular mechanisms and actions of AS.     

A Neutrophil Elastase Inhibitor,Sivelestat, Reduces Lung Injury Following Endotoxin-Induced Shock in Rats by Inhibiting HMGB1

Neutrophil elastase (NE) plays an important role in the progression of acute lung injury (ALI). Sivelestat sodium hydrate (Sivelestat) is a highly specific synthetic inhibitor of NE. High mobility group box 1 (HMGB1) is one of the key mediators in the development of sepsis. The aim of this study was to evaluate the effect of sivelestat and to determine whether it can reduce lipopolysaccharide (LPS)-induced acute lung injury in rats. Rats were randomly divided into a negative control group, an LPS-induced sepsis group, and a group treated with sivelestat prior to LPS administration. Animals in the sivelestat group received a bolus of 10 mg/kg of sivelestat injected into the intraperitoneal cavity before the LPS treatment. Furthermore, rats were administered sivelestat at 0, 1, 3, and 6 h following LPS treatment. We measured cytokine and HMGB1 levels in the serum after the induction of sepsis. In addition, we observed histopathology, wet/dry weight ratio, inducible nitric oxide synthase and HMGB1 expression in the lung tissue. Lung histopathology was significantly improved in the sivelestat group compared to the LPS group. Serum and pulmonary HMGB1 levels were lower over time among sivelestat-treated animals. Furthermore, inhibition of NF-kappaB activity was observed with the administration of sivelestat. These results suggest that sivelestat reduces LPS-induced lung injury at least partially by inhibiting inflammation and NF-kappaB activity.     

Methoxyeugenol Protects Against Lung Inflammation and Suppresses Neutrophil Extracellular Trap Formation in an LPS-Induced Acute Lung Injury Model

Inflammation - Acute lung injury (ALI) is a life-threatening acute inflammatory disease with high rates of morbidity and mortality worldwide. 4-Allyl-2,6-dimethoxyphenol (methoxyeugenol), a...     

Lysophosphatidylcholine Acyltransferase 1 Deficiency Promotes Pulmonary Emphysema via Apoptosis of Alveolar Epithelial Cells

Inflammation - Chronic obstructive pulmonary disease (COPD) is primarily caused by inhalation of cigarette smoke and is the third leading cause of death worldwide. Pulmonary surfactant, a complex...     

Protective Effects of Asiatic Acid Against Spinal Cord Injury-Induced Acute Lung Injury in Rats

The biological effects of asiatic acid (AA) on spinal cord injury (SCI)-induced acute lung injury (ALI) have not been investigated. We aimed to investigate the therapeutic efficacy and molecular mechanisms of AA on SCI-induced ALI. One-hundred and fifty Sprague–Dawley rats were randomly assigned to five groups: sham, SCI, SCI?+?dexamethasone (Dex, 2 mg/kg), SCI?+?AA (30 mg/kg), and SCI?+?AA (75 mg/kg). The influences of AA on histologic changes, pulmonary edema, neutrophil infiltration and activation, proinflammatory cytokine production, oxidative stress, and Nrf2 and NLRP3 inflammasome protein expression were estimated. AA administration at the 30- and 75-mg/kg doses significantly attenuates lung wet-to-dry weight (W/D) ratio, pulmonary permeability index (PPI), and pulmonary histologic conditions. Furthermore, the protective effects of AA might be attributed to the reduction of neutrophil infiltration, myeloperoxidase (MPO), inflammatory cytokines, reactive oxygen species (ROS), malondialdehyde (MDA), and the increase of superoxide dismutase (SOD) and catalase (CAT). Moreover, AA markedly upregulated Nrf2 levels and downregulated NLRP3 inflammasome protein expression in lung tissues. AA exhibits a protective effect on SCI-induced ALI by alleviating the inflammatory response, by inhibiting NLRP3 inflammasome activation and oxidative stress with the upregulation of Nrf2 protein levels. The use of AA may be a potential efficient therapeutic strategy for the treatment of SCI-induced ALI.     

Quercetin Protects Mice from ConA-Induced Hepatitis by Inhibiting HMGB1-TLR Expression and Down-Regulating the Nuclear Factor Kappa B Pathway

The dietary flavonoid quercetin has hepatoprotective effects. We analyzed the effects of quercetin on concanavalin A (ConA)-induced hepatitis in mice and its underlying molecular mechanisms of action. Mice were administered quercetin (50 mg/kg body weight, i.p.) or vehicle 30 min before intravenous administration of ConA. Quercetin pretreatment significantly reduced the ConA-induced elevations in plasma aminotransferase concentrations and liver necrosis, as well as reducing serum concentrations of the pro-inflammatory cytokines tumor necrosis factor (TNF)-α, interferon-γ, and interleukin-4. Quercetin pretreatment also reduced expression of high-mobility group box 1 protein (HMGB1) and toll-like receptor (TLR)-2 and TLR-4 messenger RNA (mRNA) and protein in liver tissues. Quercetin pretreatment significantly inhibited degradation of inhibitory kappa B alpha and modulated ConA-induced nuclear translocation in the liver of nuclear factor kappa B (NF-κB) p65. These results demonstrate that quercetin protects against ConA-mediated hepatitis in mice by attenuating the HMGB1–TLRs–NF-κB signaling pathway.     

Protective Effect of Antagonist of High-mobility Group Box 1 on Lipopolysaccharide-Induced Acute Lung Injury in Mice

We explored the effects of recombinant A-box (rA-box), a specific blockade for endogenous high mobility group box 1 (HMGB1) protein, on acute lung inflammation induced by lipopolysaccharide (LPS) in vivo . Acute lung injury (ALI) was produced successfully by intratracheal administration of LPS (10  μ g/mouse) in male BALB/ c mice. rA-box (0.3, 0.6 mg/mouse, i.p.) was administered 30 min prior to or 2 h after LPS exposure. Bronchoalveolar lavage fluid (BALF) was obtained to measure chemokines, proinflammatory cytokines, total cell counts and proteins at the indicated time points. It was found that rA-box caused a significant reduction in the total cells and neutrophils in BALF, a significant reduction in the W/D ratio and protein leakage at 24 h after LPS challenge. In addition, rA-box was also believed to have downregulated the expression of LPS-induced chemokines (keratinocyte-derived chemokine) and proinflammatory cytokines, including early mediator TNF-a and late mediator HMGB1. These findings confirm the significant protection of rA-box against LPS-induced ALI, and the effect mechanism of rA-box was associated with decreasing the expression of chemokines and proinflammatory cytokines.     

Preventive and Therapeutic Effects of Thymol in a Lipopolysaccharide-Induced Acute Lung Injury Mice Model

Acute lung injury (ALI) is a life-threatening syndrome which causes a high mortality rate worldwide. In traditional medicine, lots of aromatic plants—such as some Thymus species—are used for treatment of various lung diseases including pertussis, bronchitis, and asthma. Thymol, one of the primary active constituent derived from Thymus vulgaris (thyme), has been reported to exhibit potent anti-microbial, anti-oxidant, and anti-inflammatory activities in vivo and in vitro. The present study aims to investigate the protective effects of thymol in lipopolysaccharide (LPS)-induced lung injury mice model. In LPS-challenged mice, treatment with thymol (100 mg/kg) before or after LPS challenge significantly improved pathological changes in lung tissues. Thymol also inhibited the LPS-induced inflammatory cells influx, TNF-α and IL-6 releases, and protein concentration in bronchoalveolar lavage fluid (BALF). Additionally, thymol markedly inhibited LPS-induced elevation of MDA and MPO levels, as well as reduction of SOD activity. Further study demonstrated that thymol effectively inhibited the NF-κB activation in the lung. Taken together, these results suggested that thymol might be useful in the therapy of acute lung injury.