Rapamycin reverses paraquat-induced acute lung injury in a rat model through inhibition of NFκB activation

Objective: To evaluate the role of rapamycin (RAPA) in paraquat (PQ)-induced acute lung injury. Methods: Lung tissues were stained with HE and lung histology was observed. Mortality rate, and neutrophil and leukocyte count in blood and bronchoalveolar lavage fluid (BALF) were recorded. Protein content in BALF was determined by Coomassie blue staining. Malondialdehyde (MDA) content, glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activity in blood were determined by thiobarbituric acid (TBA) assay, pyrogallol autoxidation method, and modified Haefman method, respectively. The NF-κB activity was measured by gel electrophoretic mobility shift assay (EMSA). Carbon dioxide partial pressure (PaCO₂), partial pressure of oxygen (PaO₂) and pH values were measured by automated blood gas analyzer. Results: HE staining results demonstrated RAPA alleviated pathological changes of acute alveolitis in SD rats. Trend of protein content in BALF was PQ group > RAPA treatment group > control group (P < 0.05). Neutrophil and leukocyte count in RAPA treatment group was significantly lower than PQ group at 3, 5, and 7 days after injection (P < 0.05). Trend of MDA content was RAPA treatment group > PQ group > control group (P < 0.05). Trend of GSH-Px and SOD activity was control group > RAPA treatment group > PQ group (P < 0.05). Compared with PQ group, PaO₂ in RAPA treatment group was markedly higher and PaCO₂ was lower (P < 0.05). Conclusion: PQ-induced acute lung injury was effectively reversed with RAPA, through inhibition of NF-κB activation.     

Interleukin-1β-induced neutrophil recruitment and acute lung injury in hamsters

Administering recombinant interleukin-1 (IL-1) intratracheally caused lung neutrophil accumulation and lung injury in hamsters. The percentage of leukocytes that were neutrophils increased progressively in lavages from lungs of hamsters given 25, 50, or 100 ng IL-1 intratracheally 2 h before. Lung injury, reflected by increased lung lavage protein concentrations and lung lavage hemoglobin concentrations, increased 2 h after administering 100 ng IL-1. Lung injury, reflected by lung wet weight/body weight ratios, followed similar patterns, with significant increases occurring 2 h after insufflating 50 or 100 ng IL-1. Our results indicate that increased concentrations of IL-1 in lung airways can cause neutrophil recruitment and lung injury in hamsters. This mechanism may contribute to the development of lung neutrophil accumulation and lung injury that characterizes ARDS patients who have increased airway levels of IL-1.     

Early administration of propofol protects against endotoxin-induced acute lung injury in rats by inhibiting the TGF-β1-Smad2 dependent pathway

Objective

To assess the effects of propofol treatments at different time points on acute lung injury and on the expression of transforming growth factor (TGF)-β1 and the downstream target of TGF-β1, Smad 2, in the lung tissues in the endotoxic rats.

Methods

Seventy-six Wistar rats were randomly assigned to five groups: control group (saline only), endotoxemic group [lipopolysaccharide (LPS) 8 mg kg^?1, i.v.], and three propofol-treated groups. For the propofol-treated groups, propofol (5 mg kg^?1, i.v. bolus) was administered either 1 h before LPS, simultaneously with LPS, and 1 h after LPS, and all were followed by infusion of 10 mg kg^?1 h^?1 of propofol for 5 h after LPS. Lung tissues were sampled to measure myeloperoxidase activity and expression of TGF-β1 and Smad2 and to assess pulmonary microvascular permeability and histopathological changes.

Results

The hemodynamics, arterial blood gases, 5 h survival rate, pulmonary microvascular permeability, and acute lung injury scores were significantly better, and expression of TGF-β1 and Smad2 and myeloperoxidase activity in lung tissues was significantly lower in the pretreatment and simultaneous treatment groups compared to the endotoxemic group. However, there were no significant differences in all observed variables between the endotoxemic and postreatment groups. Except for TGF-β1 expression in lung tissues, the other observed variables were also not significantly different between the pretreatment and simultaneous treatment groups.

Conclusions

In the endotoxic rat model, pretreatment and simultaneous treatment with propofol provided protection against acute lung injury by inhibiting the TGF-β1-Smad2 dependent pathway.     

Anti-IFN-γ therapy alleviates acute lung injury induced by severe influenza A (H1N1) pdm09 infection in mice

Background/purposeSevere infection with influenza A (H1N1)pdm09 virus is characterized by acute lung injury. The limited efficacy of anti-viral drugs indicates an urgent need for additional therapies. We have previously reported that neutralization of gamma interferon (IFN-γ) could significantly rescue the thymic atrophy induced by severe influenza A (H1N1)pdm09 infection in BALB/c mice. A deeper investigation was conducted into the influence of neutralizing IFN-γ to the BALB/c mice weight, survival rate, and lung injury.MethodsThe BALB/c mice was infected with severe influenza A (H1N1)pdm09. Monoclonal antibodies against IFN-γ were injected into the abdominal cavities of the mice. After neutralization of IFN-γ occurred in mice infected by severe ? influenza A (H1N1)pdm09, observing the influence of neutralizing IFN-γ to the BALB/c mice weight, survival rate, lung injury.ResultOur results here showed that anti-IFN-γ therapy alleviated the acute lung injury in this mouse model. Neutralization of IFN-γ led to a significant reduction in the lung microvascular leak and the cellular infiltrate in the lung tissue, and also improved the outcome in mice mortality. Several pro-inflammatory cytokines, including interleukin (IL)-1α, tumor necrosis factor (TNF)-α and granulocyte-colony stimulating factor (G-CSF) in the bronchoalveolar lavage fluid (BALF), and the chemokines including G-CSF, monocyte chemoattractant protein-1 (MCP-1) in serum samples were found to be significantly reduced after anti-IFN-γ treatment.ConclusionThese results suggested that IFN-γ plays an important role in acute lung injury induced by severe influenza A (H1N1)pdm09 infection, and monoclonal antibodies against IFN-γ could be useful as a potential therapeutic remedy for future influenza pandemics.     

Mannose prevents acute lung injury through mannose receptor pathway and contributes to regulate PPARγ and TGF-β1 level

Mannose has been reported to prevent acute lung injury (ALI), and mannose receptor (MR) has been demonstrated to have a role. The rationale for this study is to characterize the mechanism by which mannose and MR prevent lipopolysaccharide (LPS)-induced ALI. Male ICR mice were pretreated mannose by intravenous injection 5 min before and 3 h after intratracheal instillation of LPS. Pathological changes, proinflammatory mediator, peroxisome proliferator activated receptor gamma (PPARγ), MR, and transforming growth factor β1 (TGF-β1) levels were determined. The RAW264.7 cells were pretreated with mannose and stimulated with LPS for 3 h. Proinflammatory mediator and TGF-β1 in the culture media, PPARγ, MR, and TGF-β1 expression in RAW 264.7 cells were measured. Mannose markedly attenuated the LPS-induced histological alterations and inhibited the production of proinflammatory mediator in mice and in RAW 264.7 cells. Mannose increased PPARγ and MR expression, and inhibited TGF-β1 stimulated by LPS. Interestingly, competitive inhibition of MR with mannan was associated with elimination of the anti-inflammatory effects of mannose, and reversed effects of mannose of regulation to PPARγ and TGF-β1. MR is important in increasing PPARγ and decreasing TGF-β1 expression and plays a critical role in mannose’s protection against ALI.     

Erratum to: Early administration of propofol protects against endotoxin-induced acute lung injury in rats by inhibiting the TGF-β1-Smad2 dependent pathway

Objective  

To assess the effects of propofol treatments at different time points on acute lung injury and on the expression of transforming growth factor (TGF)-β1 and the downstream target of TGF-β1, Smad 2, in the lung tissues in the endotoxic rats.     

Time-dependent expression of endothelin-1 in lungs and the effects of TNF-α blocking peptide on acute lung injury in an endotoxemic rat model

Endothelin (ET)-1 is a potent vasoconstrictor that has been implicated in the pathogenesis of a number of diseases, and some studies suggest that circulating ET-1 is elevated in sepsis. The present study investigated whether ET plays a role in sepsis-mediated acute lung injury and whether its expression could be down regulated by blockade of TNF-α in septic lung. Male Wistar rats at 8 weeks of age were administered with either saline or lipopolysaccharide (LPS) at different time points (1, 3, 6 and 10 h) and various tests were then performed. The features of acute lung injury were observed at 1 h after LPS administration, which gradually became severe with time. Systolic and diastolic pressures were reduced just about one hour after LPS administration, whereas pulmonary TNF-α levels were significantly increased at various time points after LPS administration. LPS induced a time-dependent expression of ET-1 and ET(A) receptor in the lungs compared to control, peaking and increasing by 3 fold at 6 h after induction of endotoxemia, whereas levels of ET(B) receptor, which has vasodilating effects, were remarkably down regulated time-dependently. We conclude that time-dependent increase of ET-1 and ET(A) receptor with the down regulation of ET(B) receptor may play a role in the pathogenesis of acute lung injury in endotoxemia. Finally, treatment of LPS-administered rats with TNF-α blocking peptide for three hours significantly suppressed levels of pulmonary ET-1. These data taken together, led us to conclude that differential alteration in ET expression and its receptors may be mediated by TNF-α and may, in part, account for the pathogenesis of acute lung injury in endotoxemia.     

Thalidomide alleviates acute pancreatitis-associated lung injury via down-regulation of NFκB induced TNF-α

Aims

We studied the effect of thalidomide on NFκB-induced TNF-α in acute pancreatitis-associated lung injury in the rat.

Methods

Rats were intragastrically administered thalidomide (100 mg/kg) daily for 8 days and then acute pancreatitis was induced by retrograde infusion of 5% sodium taurocholate into the rat biliopancreatic duct. Serum amylase (AMY), blood oxygen partial pressure (PaO₂), ratios of lung wet/dry weight, and cytoplasmic IκBα and TNF-α protein and nuclear NFκBp65 protein were measured. Also, lung NFκBp65 and TNF-α mRNA were measured.

Results

Compared with the model group, the pathological score of the pancreas and lung, serum AMY, ratios of lung wet/dry weight, and lung NFκBp65 and TNF-α mRNA and protein of rats given thalidomide were decreased significantly (P < 0.01), but PaO₂ and IκBα protein was elevated significantly (P < 0.01).

Conclusion

Thalidomide may inhibit TNF-α expression via down-regulation of the NFκB signaling pathway to alleviate acute pancreatitis-associated lung injury in rats.     

NLRP3 inflammasome activation regulated by NF-κB and DAPK contributed to paraquat-induced acute kidney injury

Paraquat can result in dysfunction of multiple organs after ingestion in human. However, the mechanisms of nucleotide-binding domain and leucine-rich repeat containing protein 3 (NLRP3) inflammasome activation in acute kidney injury have not been clearly demonstrated. The aim of this study was to determine the effect of NLRP3 inflammasome activation and its regulation by nuclear factor-kappa B (NF-κB) and death-associated protein kinase (DAPK). Male Wistar rats were treated with intraperitoneal injection of paraquat at 20 mg/kg, and NF-κB inhibitor BAY 11-7082 was pretreated at 10 mg/kg 1 h before paraquat exposure. Additionally, rat renal tubular epithelial cells (NRK-52E) were transfected with small interfering RNA (siRNA) against DAPK to evaluate its role in NLRP3 inflammasome activation. DAPK and NLRP3 inflammasome were evaluated by immunohistochemistry staining or Western blot; the pro-inflammatory cytokines including tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and interleukin-18 (IL-18) were measured via ELISA. The results showed that NF-κB, DAPK, and NLRP3 inflammasome were activated in paraquat (PQ)-treated rat kidney; the secretion of pro-inflammatory cytokines was significantly increased. These toxic effects were attenuated by NF-κB inhibitor. Besides, the activation of NLRP3 inflammasome and secretion of IL-1β and IL-18 in paraquat-treated rat renal tubular epithelial cells were inhibited by siRNA against DAPK. In conclusion, NLRP3 inflammasome activation regulated by NF-κB and DAPK played an important role in paraquat-induced acute kidney injury.     

p-Synephrine suppresses lipopolysaccharide-induced acute lung injury by inhibition of the NF-κB signaling pathway

Objective

We investigated whether p-synephrine exerts potent anti-inflammatory effects against acute lung injury (ALI) induced by lipopolysaccharide (LPS) in vivo, and we further investigated the inhibitory mechanism of p-synephrine in LPS-induced ALI.

Methods

Lipopolysaccharide (0.5 mg/kg) was instilled intranasally in phosphate-buffered saline to induce acute lung injury, and 6, 24, and 48 h after LPS was given, bronchoalveolar lavage fluid was obtained to measure pro-inflammatory mediator. We also evaluated the effects of p-synephrine on LPS-induced the severity of pulmonary injury. The phosphorylation of nuclear factor-κB (NF-κB) p65 protein was analyzed by Western blotting.

Results

Our data showed that p-synephrine significantly reduced the amount of inflammatory cells, the lung wet-to-dry weight (W/D) ratio, reactive oxygen species, myeloperoxidase activity and enhanced superoxide dismutase (SOD) in mice with LPS-induced ALI. Tumor necrosis factor α and interleukin (IL)-6 concentrations decreased significantly while the concentration of IL-10 was significantly increased after p-synephrine pretreatment. In addition, p-synephrine suppressed not only the phosphorylation of NF-κB but also the degradation of its inhibitor (IκBα).

Conclusions

These results suggested that the inhibition of NF-κB activation and the regulation of SOD are involved in the mechanism of p-synephrine’s protection against ALI.     

Perioperative “remote” acute lung injury: recent update

Perioperative acute lung injury (ALI) is a syndrome characterised by hypoxia and chest radiograph changes. It is a serious post-operative complication, associated with considerable mortality and morbidity. In addition to mechanical ventilation, remote organ insult could also trigger systemic responses which induce ALI. Currently, there are limited treatment options available beyond conservative respiratory support. However, increasing understanding of the pathophysiology of ALI and the biochemical pathways involved will aid the development of novel treatments and help to improve patient outcome as well as to reduce cost to the health service. In this review we will discuss the epidemiology of peri-operative ALI; the cellular and molecular mechanisms involved on the pathological process; the clinical considerations in preventing and managing perioperative ALI and the potential future treatment options.     

Geniposide alleviates pressure overload in cardiac fibrosis with suppressed TGF-β1 pathway

BackgroundCardiac fibrosis is one of the main contributors to the pathogenesis of heart failure. Geniposide (GE), a major iridoid in gardenia fruit extract, has recently been reported to improve skeletal muscle fibrosis through the modulation of inflammation response. This investigation aimed to illuminate the cardio-protective effect and the potential mechanism of GE in cardiac fibrosis.Material and methodsA transverse aortic contraction (TAC) induction mice model was established and GE (0 mg/kg; 10 mg/kg; 20 mg/kg; 40 mg/kg) was administered by oral gavage daily for 4 weeks. Hemodynamic parameters, Masson’s trichrome stain, and hematoxylin-eosin (HE) staining were estimated and cardiomyocyte fibrosis, interstitial collagen levels, and hypertrophic markers were analyzed using qPCR and western blot. In vitro, H9C2 cells were exposed to the Ang II (1 μM) pretreated with GE (0.1 μM, 1 μM, and 10 μM). Cardiomyocyte apoptosis was detected. Moreover, the transforming growth factor β1 (TGF-β1)/Smad2 pathway was assessed in vivo and in vitro.ResultsGE significantly ameliorated TAC-induced cardiac hypertrophy, ventricular remodeling, myocardial fibrosis, and improved cardiac function in vivo, and it inhibited Ang II-induced cardiomyocyte apoptosis in vitro. We further observed that the inflammatory channel TGF-β1/Smad2 pathway was suppressed by GE both in vivo and in vitro.ConclusionThese results indicate that GE inhibited myocardial fibrosis and improved hypertrophic cardiomyocytes with attenuated the TGF-β1/Smad2 pathway and proposed to be an important therapeutic of cardiac fibrosis reduced by TAC.     

Increased Tbx1 expression may play a role via TGFβ-Smad2/3 signaling pathway in acute kidney injury induced by gentamicin

T-box 1 (Tbx1) gene is closely involved in embryonic kidney development. To explore the role of Tbx1 in acute kidney injury (AKI) and the underlying mechanism, we detected the expression of Tbx1 and components of transforming growth factor-beta (TGF-β) signaling pathways including TGF-β, phosphorylated Smad2/3 (p-Smad2/3) and phosphorylated Smad1/5/8 (p-Smad1/5/8) in kidney tissues derived from a rat model for AKI induced by gentamicin (GM). Apoptosis of renal cells was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL), along with the expression of two essential genes involved in apoptosis, caspase-3 and Bcl-2. Correlation between Tbx1 expression and the number of TUNEL-positive cells was analyzed by a Spearman test. Expression of TGF-β, p-Smad2/3 and p-Smad1/5/8 in Tbx1-knockdown NRK cells was also analyzed by real-time RT-PCR and Western blotting. Markedly increased Tbx1 expression was found in the injured kidney tissues, which has activated the TGFβ-Smad2/3 pathway whilst suppressed Smad1/5/8 expression. Conversely, decreased TGF-β and p-Smad2/3 levels, and elevated p-Smad1/5/8 levels were detected in Tbx1-knockdown NRK cells. More apoptotic cells were detected in the injured kidneys, which has well correlated with the expression of Tbx1. Expression of caspase-3 was markedly increased, while Bcl-2 was decreased in the injured kidney tissues. Above findings suggested that activation of Tbx1 is involved in AKI through the TGFβ-Smad2/3 pathway. Tbx1 expression may therefore serve as a marker for AKI, and Tbx1-blocking therapies may provide an option for treating GM-induced nephropathy.     

Inhibition of PKR ameliorates lipopolysaccharide-induced acute lung injury by suppressing NF-κB pathway in mice

Acute lung injury (ALI) is characterized by dramatic lung inflammation and alveolar epithelial cell death. Although protein kinase R (PKR) (double-stranded RNA-activated serine/threonine kinase) has been implicated in inflammatory response to bacterial cell wall components, whether it plays roles in lipopolysaccharide (LPS)-induced ALI remains unclear. This study was aimed to reveal whether and how PKR was involved in LPS-induced ALI pathology and the potential effects of its specific inhibitor, C16 (C₁₃H₈N₄OS). During the experiment, mice received C16 (100 or 500 ug/kg) intraperitoneally 1?h before intratracheal LPS instillation. Then, whole lung lavage was collected for analysis of total protein levels and proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6. The lungs were tested for Western blot, transferase-mediated dUTP nick-end labeling (TUNEL) stain and immunohistochemistry. Results showed that PKR phosphorylation increased significantly after LPS instillation. Furthermore, PKR specific inhibition attenuated LPS-induced lung injury (hematoxylin and eosin stain), reduced lung protein permeability (total protein levels in whole lung lavage) and suppressed proinflammatory cytokines (TNF-α, IL-1β and IL-6) and lung apoptosis (TUNEL stain and caspase3 activation). Moreover, mechanism-study showed that C16 significantly suppressed I kappa B kinase (IKK)/I kappa B alpha (IκBα)/NF-κB signaling pathway after LPS challenge. These findings suggested that PKR inhibition ameliorated LPS-induced lung inflammation and apoptosis in mice by suppressing NF-κB signaling pathway.     

MicroRNA-21a enhances fibrosis-associated gene expression in TGF-β1-induced rat H9c2 myoblasts

<正>AIM:To investigate the expression of fibrosis-related genes and microRNAs in TGF-β1-induced H9c2 cells.METHODS:The expression of fibrosis-associated genes,including Col3a1,α-SMA,FN1,CTGF and TSP-1,and miR-16,-21a and-29b was detected in TGF-β1-induced H9c2 cells by quantitative real-time PCR.The activations of Smad3 and NF-κB signaling in TGF-β1-treated H9c2     

Inhibition of TGF-β1 promotes functional recovery after spinal cord injury

Trauma to the spinal cord initiates a series of cellular and biochemical processes that damage both neurons and glia. TGF-β and its receptors are expressed around the injury site following a spinal cord injury. Here, we report that the intrathecal administration of a neutralizing antibody to TGF-β1 in rats with thoracic spinal cord contusion results in a significant enhancement of the locomotor recovery. The inhibition of TGF-β1 suppresses glial scar formation and upregulates microglia/macrophage activation after the injury, presumably providing a favorable environment for restoration of the neural network. Rats treated with the anti-TGF-β1 antibody exhibited a mild enhancement of growth and/or preservation of axons in the injured spinal cord caudal to the site of contusion. These results support the possibility of using TGF-β1 inhibitors in the treatment of human spinal cord injuries.     

Diagnosis of transfusion-related acute lung injury: TRALI or not TRALI?

TRALI is a challenging diagnosis for both the transfusion specialist and the clinician. A Canadian consensus panel has recently proposed guidelines to better define TRALI and its implications. The guidelines recommend classifying each suspected case in one of the following 3 categories: (1) "TRALI," (2) "Possible TRALI," or (3) "Not TRALI." We report the clinical presentation, laboratory evaluation, and management of 3 patients with respiratory failure (RF) following allogeneic blood transfusions. These patients all experienced RF within 6 hr post-transfusion. Based on a review of the clinical and laboratory data and applying the Canadian guidelines, the first patient, a 67-yr-old man with chronic myelomonocytic leukemia, was diagnosed as "TRALI" due to the sudden onset of RF requiring intensive resuscitation. The second patient, a 55-yr-old man with aplastic anemia, was diagnosed as "Possible TRALI" due to pre-existing RF that worsened after blood transfusion. The third patient, a 1-yr-old male, was diagnosed as transfusion associated circulatory overload (TACO) and "Possible TRALI," although his RF improved after treatment with diuretics. In all 3 cases, the blood donor center was informed of the suspected TRALI reactions. The remaining blood products from the donors associated with these reactions were quarantined. After review of the clinical data, the donors associated with cases #1 and #3 were screened by the blood center for granulocyte and HLA antibodies. Using a Luminex flow bead array, the following class I and class II antibodies specific for patient #1 were identified in the respective donor: anti-A25, B8, B18, and anti-DR15, DR 17. Subsequently, donor #1 was permanently deferred. A non-specific IgM anti-granulocyte antibody was identified in the donor associated with case #3, and this donor was subsequently disqualified from plasma and platelet donations. In conclusion, the Canadian guidelines to categorize patients suspected of TRALI provide a useful framework for evaluation of these patients and their respective blood donors.