Toll-like receptor 4 monoclonal antibody attenuates lipopolysaccharide-induced acute lung injury in mice

Interleukin-1 beta signals through the ERK signalling pathway to modulate human placental trophoblast migration and invasion in the first trimester of pregnancy

INTRODUCTION

Interleukin-1 beta (IL-1β) can promote cell migration, invasion and metastasis in various cancer cells. The mechanism of its role in human trophoblast has not been fully investigated. Therefore, we aimed to investigate the expression level of IL-1β in first trimester decidua and placenta and its potential role in regulation of extravillous trophoblast cell (EVT) invasion and migration.

METHODS

First trimester placenta and decidua were collected to study the expression levels of IL-1β and its receptors by immunohistochemical staining. Primary isolates of first trimester EVT or the HTR-8/SVneo trophoblast like cell line were used to assess migration and invasion. Matrix metalloproteinase levels were assessed by gelatin zymography and ELISA. The phosphorylation profile of signaling pathway proteins was detected with the Proteome Profiler Human Phospho-Kinase Array Kit. Differentially expressed proteins in cells was detected and verified by Western Blot.

RESULTS

IL-1β, its receptors and antagonist are expressed in first trimester placenta and decidua, exogenous IL-1β stimulates trophoblast cell outgrowth, migration and invasion through the ERK signaling pathway. IL-1β was significantly increased in the placenta at 6-7 weeks gestation compared with 8-9 weeks gestation (P < 0.0001). Transwell and RTCA assays indicated that IL-1β stimulates the invasion and migration of EVT. In addition, IL-1β promoted the phosphorylation of ERK 1/2. It also promoted the expression of MMP2 and MMP9 in EVT as demonstrated by gelatin zymography assay and enzyme linked immunosorbent assay.

DISCUSSION

This study demonstrated IL-1β expression in placenta and decidua, and that it regulates EVT invasion and migration.

Oleocanthal alleviated lipopolysaccharide-induced acute lung injury in chickens by inhibiting TLR4/NF-κB pathway activation

This study aimed to investigate the ameliorative effect of oleocanthal (OC) on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in chickens and its possible mechanisms. In total, 20 chickens were randomly divided into 4 groups: control (CON) group, LPS group, LPS + OC group, and OC group. LPS + OC and OC groups were intragastrically administered a 5 mg/kg·d OC dose for 7 d. On d 8, the LPS group and LPS + OC group were intratracheally administered 2 mg/kg LPS for 12 h. It was found that OC ameliorated the pathological morphology and significantly suppressed apoptosis after OC treatment in LPS-induced ALI chicken (P < 0.01). Antioxidant capacity was higher in the LPS + OC group compared with the LPS group (P < 0.01). OC downregulated the related genes and proteins expression of toll-like receptor 4/nuclear factor-κB (TLR4/NF-κB) pathway in LPS group (P < 0.01). In conclusion, OC supplementation can alleviate LPS-induced ALI in chickens by suppressing apoptosis, enhancing lung antioxidant capacities and inhibiting TLR4/NF-κB pathway activation.

Anti-inflammatory effects of microRNA-223 on sepsis-induced lung injury in rats by targeting the Toll-like receptor signaling pathway

The aim of the present study was to investigate the mediation of micro RNA (miR)-223 on the anti-inflammatory effect of the Toll-like receptor (TLR) signaling pathway on sepsis-induced lung injury in rats via negatively regulating the expression of interleukin (IL)-6. Sprague-Dawley rats were used in the present study. It was determined whether miR-223 is differentially expressed in the lung using reverse transcription-quantitative PCR techniques and the content of cytokines in bronchoalveolar lavage (BAL) fluid was detected. The protein expression levels of TLR4 and nuclear factor (NF)-κB p65 were examined by western blotting and the pathological changes in the lung tissues of the sepsis group were observed. Hematoxylin and eosin was used to stain the lung tissues. The alveoli in the sham group exhibited a normal structure and morphology. In the sepsis group, the alveoli of the lung tissues were surrounded by numerous neutrophils, the mesenchyme was swollen, regions of the alveolar wall exhibited fibrosis and the alveolar wall was thickened. Furthermore, in the sepsis group, miR-223 expression was increased in the lung tissues when compared with that in the sham group. The content of cytokines, IL-6 and IL-1β in the BAL fluid was significantly increased when compared with that of the sham group and TLR4 and NF-κB were also highly expressed. In addition, when compared with RAW264.7 cells that were overexpressing miR-223, the content of IL-6 and IL-1β in the supernatant and protein expression of TLR and NF-κB in cells were markedly decreased. Thus, it was demonstrated that miR-223 negatively regulated the expression of IL-6, mediating the TLR4/NF-κB signaling pathway and exerting an anti-inflammatory effect in sepsis-induced lung injury.

Immune Dysregulation in Children With Down Syndrome

Down syndrome (DS) is the most common genetic syndrome associated with immune defects. The extent of immune dysregulation in DS is substantial, spanning the innate and adaptive systems and including anomalies in: T and B cells, monocytes, neutrophil chemotaxis, circulating cytokines, and suboptimal antibody responses which all contribute to an increased risk of infections, poorer clinical outcomes and chronic inflammation in this vulnerable cohort. Other aspects of innate immunity may also be abnormal and contribute to the increased morbidity and warrant further interrogation such as: gamma delta T cell function, the inflammasome, Toll-like receptors and their pathways. Pharmacotherapies such as pavilizumab, pneumococcal and influenza immunizations, as well as potential immunoprophylactic agents such as pidotimod, azithromycin and Broncho-Vaxom may help alleviate the infectious consequences. Children with DS need to be managed with a heightened sense of awareness and urgency in the setting of sepsis and signs of chronic inflammation need regular screening and appropriate follow up.

Effects of glycyrrhizin on lipopolysaccharide-induced acute lung injury in a mouse model

Background

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are serious clinical disease entities characterized by inflammatory pulmonary edema, which lead to acute hypoxic respiratory failure through various etiologies. According to the studies to date, ALI/ARDS has been recognized as a form of multiorgan failure related to overactive immune response, and overproduction of proinflammatory cytokines released from activated inflammatory cells are considered to play a key role in the development of ALI. Glycyrrhizin (GL) is an extractive component derived from Glycyrrhiza glabra (licorice), which has recently been reported to have various pharmacological effects like anti-inflammatory, anti-tumor, hepato-protective, and anti-viral activities. Nevertheless, the therapeutic effect of GL in ALI is still unclear. The aim of this study was to investigate therapeutic effects of GL on lipopolysaccharide (LPS)-induced ALI in a mouse model and to elucidate explicable mechanisms involved.

Methods

A total of 36 BALB/c mice (6-week-old, 27.7±1.9-gram body weight) were randomly divided into 3 groups: the control group (normal saline was administered intravenously, n=10), the LPS group (LPS 50 mg/kg was intraperitoneally administered, n=13), and the LPS + GL group (GL was administered intravenously immediately and 12 hours after LPS injection, n=13). Mice were sacrificed after 24 hours, and bronchoalveolar lavage fluid (BALF) was collected for the estimation of protein content, inflammatory cell counts, proinflammatory cytokines, myeloperoxidase (MPO) activity, and expressions of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and nuclear factor kappa B (NF-κB). Then, the lungs were excised for molecular target, histopathological, and immunohistochemical examinations.

Results

Compared to the LPS group, GL significantly decreased protein content, inflammatory cell counts, tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), IL-6, MPO activity, and expressions of COX-2, iNOS, and NF-κB in the LPS + GL group. GL attenuated migration and infiltration of inflammatory cells, showing a marked decrease in CD 11b-positive cells (26.77%±0.83% vs. 41.77%±0.81% vs. 23.23%±1.92%, P<0.05) as well as CXCR4-/CXCR1-positive cells (CXCR4: 37.23%±1.00% vs. 59.37%±2.37% vs. 47.45%±4.36%; CXCR1: 32.10%±1.56% vs. 47.03%±1.99% vs. 21.70%±6.50%; all P<0.05) in the control, LPS, and LPS + GL groups. Additionally, immunohistochemistry showed that the expression of Toll-like receptor 4 (TLR-4) was inhibited by GL.

Conclusions

The results of this study indicate that GL may have anti-inflammatory and protective effects on LPS-induced ALI in mice. GL inhibited proinflammatory cytokines playing a key role in the initial phase of inflammatory response, which suggests that inhibition of the TLR-4/NF-κB signal pathway would be a possible mechanism underlying the action of GL. Thus, GL can be used as a novel therapeutic strategy for pulmonary inflammation.

Role of TLR4-p38 MAPK-Hsp27 signal pathway in LPS-induced pulmonary epithelial hyperpermeability

Background

The breakdown of alveolar barrier dysfunction contributes to Lipopolysaccharide stimulated pulmonary edema and acute lung injury. Actin cytoskeleton has been implicated to be critical in regulation of epithelial barrier. Here, we performed in vivo and in vitro study to investigate role of TLR4-p38 MAPK-Hsp27 signal pathway in LPS-induced ALI.

Methods

For in vivo studies, 6–8-week-old C57 mice were used, Bronchoalveolar lavage Fluid /Blood fluorescent ratio, wet-to-dry lung weight ratio, as well as protein concentrations and neutrophil cell counts in BALF were detected as either directly or indirectly indicators of pulmonary alveolar barrier dysfunction. And hematoxylin and eosin staining was performed to estimate pulmonary injury. The in vitro explorations of transepithelial permeability were achieved through transepithelial electrical resistance measurement and testing of FITC-Dextran transepithelial flux in A549. In addition, cytoskeletal rearrangement was tested through F-actin immunostaining. And SB203580 was used to inhibit p38 MAPK activation, while siRNA was administered to genetically knockdown specific protein.

Results

We showed that LPS triggered activation of p38 MAPK, rearrangement of cytoskeleton which resulted in severe epithelial hyperpermeability and lung edema. A549 pretreated with TLR4 siRNA、p38 MAPK siRNA and its inhibitor SB203580 displayed a lower permeability and fewer stress fibers formation after LPS stimulation, accompanied with lower phosphorylation level of p38 MAPK and Hsp27, which verified the involvement of TLR4-p38 MAPK-Hsp27 in LPS-evoked alveolar epithelial injury. Inhibition of p38 MAPK activity with SB203580 in vivo attenuated pulmonary edema formation and hyperpermeability in response to LPS.

Conclusions

Our study demonstrated that LPS increased alveolar epithelial permeability both in vitro and in vivo and that TLR4- p38 MAPK- Hsp27 signal pathway dependent actin remolding was involved in this process.

Two indole-2-carboxamide derivatives attenuate lipopolysaccharide-induced acute lung injury by inhibiting inflammatory response

Acute lung injury (ALI) is the leading cause of mortality in the intensive care unit. Currently, there is no effective pharmacological treatment for ALI. In our previous study, we reported that Lg25 and Lg26, two indole-2-carboxamide derivatives, inhibited the lipopolysaccharide (LPS)-induced inflammatory cytokines in vitro and attenuated LPS-induced sepsis in vivo. In the present study, we confirmed data from previous studies that LPS significantly induced pulmonary edema and pathological changes in lung tissue, increased protein concentration and number of inflammatory cells in bronchoalveolar lavage fluids (BALF), and increased inflammatory cytokine TNF-α expression in serum and BALF, pro-inflammatory genes expression, and macrophages infiltration in lung tissue. However, pretreatment with Lg25 and Lg26 significantly attenuated the LPS-induced changes in mice. Taken together, these data indicate that the newly discovered indole-2-carboxamide derivatives could be particularly useful in the treatment of inflammatory diseases such as ALI.

Apolipoprotein M Protects Against Lipopolysaccharide-Induced Acute Lung Injury via Sphingosine-1-Phosphate Signaling

It had been demonstrated that apolipoprotein M (apoM) is an important carrier of sphingosine-1-phosphate (S1P) in blood, and the S1P has critical roles in the pathogenesis of sepsis-induced acute lung injury (ALI). In the present study, we investigated whether apoM has beneficial effects in a mouse model after lipopolysaccharide (LPS)-induced ALI. Forty-eight mice were divided into two groups: male C57BL/6 wild-type (apoM^+/+) group (n = 24) and apoM gene-deficient (apoM^-/-) group (n = 24) and then randomly subdivided into four subgroups (n = 6 each) according to different intraperitoneal (i.p.) injection: control group, W146 group, LPS group, and LPS + W146 group. Serum levels of interleukin-1 beta (IL-1β) and mRNA levels of IL-1β, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), lung histology, wet/dry weight ratio, and immunohistochemistry were measured at 3 h after the baseline and compared in each group. Our results clearly demonstrated that IL-1β mRNA levels and other inflammatory biomarkers were significantly increased in the lungs of LPS-induced ALI apoM^-/- mice compared to those of the apoM^+/+ mice. Moreover, when apoM^+/+ mice were treated with W146, a S1P receptor (S1PR1) antagonist, these inflammatory biomarkers could be significantly upregulated by LPS-induced ALI. Therefore, it suggests that apoM-S1P-S1PR1 signaling might underlie the pathogenesis of ALI and apoM could have physiological benefits to alleviate LPS-induced ALI.

Curcumin inhibits lipopolysaccharide (LPS)-induced endotoxemia and airway inflammation through modulation of sequential release of inflammatory mediators (TNF-α and TGF-β1) in murine model

OBJECTIVE

Curcumin (diferuloylmethane), a major component of turmeric is well known for its anti-inflammatory potential. Present study investigates sequential release of inflammatory mediators post LPS challenge (10 mg/kg,i.p.) causing lung inflammation and its modulation by curcumin through different routes (20 mg/kg, i.p and 10 mg/kg, i.n.) in murine model. Dexamethasone (1 mg/kg, i.p) was used as standard drug.

METHODS

Lung Inflammation was evaluated by histopathological analysis, myeloperoxidase (MPO) activity followed by inflammatory cell count and total protein content measurements in bronchoalveolar fluid (BALF). Reactive oxygen species (ROS), nitrite and TNF-α levels were measured as markers of endotoxin shock at different time points (1-72 h). The mRNA expression of transforming growth factors-β1 (TGF-β1), iNOS and Toll-like receptor-4 (TLR-4) were measured followed by Masson's trichrome staining and hydroxyproline levels as collagen deposition marker leading to fibrotic changes in lungs.

RESULTS

We found that LPS-induced lung inflammation and injury was maximum 24-h post LPS challenge shown by MPO and histological analysis which was further supported by elevated nitrite and ROS levels whereas TNF-α level was highest after 1 h. Endotoxin-induced mortality was significantly reduced in curcumin (i.p) pretreatment groups up to 72-h post LPS challenge. Significant inhibition in mRNA expression of iNOS, TGF-β1 and TNF-α level was noted after curcumin treatment along with lowered MPO activity, inflammatory cell count, ROS, nitrite levels and collagen deposition in lungs.

CONCLUSION

Our results suggest that higher endotoxin dose causes inflammatory mediator release in chronological order which tend to increase with time and reached maximum after 24-h post-endotoxin (LPS) exposure. Intraperitoneal route of curcumin administration was better in modulating inflammatory mediator release in early phase as compared to intranasal route of administration. It can be used as supplementary therapeutic intervention at early stage of endotoxemia, having fewer side effects.

Lard-based high-fat diet increases secretory leukocyte protease inhibitor expression and attenuates the inflammatory response of acute lung injury in endotoxemic rats

BACKGROUND & AIMS

Acute lung injury (ALI) is less severe in obese than in nonobese patients, but the mechanism is unclear. Secretory leukocyte protease inhibitor (SLPI) is the key anti-inflammatory protein in various lung diseases. We have previously reported changes of the surgical stress in obese rats using lard-based high-fat diet (HFD). The purpose of this study was to elucidate the effect of lard-based HFD on the pathophysiology of lipopolysaccharide (LPS)-induced ALI, and the role of SLPI expression.

METHODS

Male Wistar rats were fed lard-based HFD (60 kcal% fat) or control diet (CD) for either 4 or 12 weeks and were killed after intraperitoneal LPS injection. Analyses included messenger RNA expression of TNF-α, macrophage inflammatory protein (MIP)-2, inducible nitric oxide synthase (iNOS), IL-10 and SLPI in the lung tissue and bronchoalveolar lavage fluid, and histology of the lungs.

RESULTS

Rats fed HFD for 12 weeks showed suppression of the lung injury and oxidative stress after LPS injection, as indicated by reduction of pulmonary TNF-α, MIP-2 and iNOS mRNA expression and 8-hydroxy-2'-deoxyguanosine immunostaining. The increased pulmonary SLPI caused by lard was associated with decreased pro-inflammatory cytokines and oxidative stress, which eventually resulted in the prevention of ALI. Those effects of lard on LPS-induced ALI were greater after 12 weeks than after 4 weeks feeding, as indicated by the reduction of TNF-α, MIP-2 and iNOS levels.

CONCLUSIONS

Feeding lard-based HFD for 12 weeks attenuated LPS-induced ALI with increased pulmonary SLPI expression in rats.