Modulation of IL-1 beta, IL-6, IL-8, TNF-alpha, and TGF-beta secretions by alveolar macrophages under NO2 exposure

Modulatory apoptotic effects of sinomenine on Mycoplasma pneumonia through the attenuation of inflammation via ERK/JNK/NF-κB signaling pathway

Mycoplasma pneumoniae (MPP) induced pneumonia is a common disease of children. Sinomenine (SIN) is an isoquinoline mainly sequestered from Sinomenium acutum. It is a promising drug for treating arthritis, lung, colon, liver and gastric cancer. Hence, the present study investigated the role and mechanism of SIN treatment in MPP induced pneumonia in experimental in-vivo mice model. The BALB/c male mice were separated into four groups (n = 6 mice/group): normal, MPP, MPP + SIN (20 mg/kg bw), and SIN (20 mg/kg bw) alone. Results were expressed as mean ± SD. Data were analyzed using one way Analysis of Variance (ANOVA) with the Dunnett's post hoc test using SPSS v 18.0. P value < 0.05 was considered significant. The total protein, cell count, inflammatory cytokines, MP-IgM, Monocyte chemo attractant protein-1 (MCP-1), and MP-DNA were measured. The protein expressions of Bax/Bcl-2, ERK, JNK, NF-κB were analyzed and histopathology of lungs was examined. SIN treatment significantly (p < 0.05) reduced the total proteins, cell counts in BALF, inflammatory cytokines, MP-IgM, MCP-1, MP-DNA and reversed the histological alterations. SIN attenuated the apoptotic pathway through the modulation of Bax/Bcl-2 expression. SIN alleviated pulmonary inflammatory mediators and apoptosis in MPP-infected mice via suppression of ERK/JNK/NF-κB signaling. SIN administration diminished inflammation and lung fibrosis by inhibiting apoptosis in MPP mice. Hence, SIN is a potential natural protective remedy for MPP.

Quercetin-Rich Ethanolic Extract of Polygonum odoratum var Pakphai Leaves Decreased Gene Expression and Secretion of Pro-Inflammatory Mediators in Lipopolysaccharide-Induced Murine RAW264.7 Macrophages

Polygonum odoratum var. Pakphai has been used in traditional Thai medicine for the treatment of flatulence and constipation and to relieve the inflammation caused by insect bites. Quercetin (Q), which is abundant in plant-based foods, has been found to exert anti-inflammatory properties. This study evaluated the anti-inflammatory activity of P. odoratum ethanolic extract in RAW264.7 macrophage cells. Leaves were extracted with 50% ethanol, phenolics and flavonoids were then analyzed using UHPLC-QTOF-MS and HPLC-DAD. RAW264.7 cells were induced with lipopolysaccharides (LPSs). They were then treated with the extract and prostaglandin E2 (PGE2), and interleukin-6 (IL-6) and tumor necrotic factor-alpha (TNF-α) concentrations were determined. Levels of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), IL-6 and TNF-α mRNAs were analyzed using qRT-PCR. Chemical analysis demonstrated that the extract was abundant with Q while also containing catechin, gallic acid, epicatechin gallate and coumarin. The extract increased the viability of RAW264.7 cells and dose-dependently decreased nitric oxide production, PGE2, IL-6 and TNF-α levels in the medium from the LPS-induced RAW264.7 cell culture. Consistently, COX-2, iNOS, IL-6 and TNF-α mRNA levels were decreased in a concentration-dependent manner (p < 0.05). Thus, the quercetin-rich ethanolic extract derived from P. odoratum var Pakphai leaves can exert anti-inflammatory activity in LPS-induced RAW264.7 cells through a reduction of the pro-inflammatory mediator response.

Short-term effects of ambient air pollution on chronic obstructive pulmonary disease admissions in Beijing, China (2013-2017)

Purpose

Evidence between air pollution and COPD admissions is inconsistent and limited in China. In this study, we aimed to explore the effects of air pollutants on COPD admissions in Beijing, China.

Patients and methods

Daily COPD hospital admission visits derived from tertiary and secondary hospitals in Beijing were retrieved from January 2013 to February 2017. Air pollutant levels and meteorological data over the same periods were also achieved. Generalized additive model was applied to estimate the percentage changes with 95% CIs in daily admissions corresponding to 10 µg/m³ increases in pollutants levels [1 mg/m³ in carbon monoxide (CO)], stratified by age, gender, and season.

Results

Seventy-three thousand seventy-six COPD hospital admission visits were included with mean daily visits of 48 (21). Cumulative lag effect with per 10 µg/m³ increase in air pollutant levels was largest for nitrogen dioxide (NO₂) with 3.03% (95% CI: 1.82%-4.26%) at lag 06, for sulfur dioxide (SO₂) with 2.07% (95% CI: 1.00%-3.15%) at lag 01, for particulate matter ≤10 µm in aerodynamic diameter (PM₁₀) with 0.92% (95% CI: 0.55%-1.30%) at lag 07, and for particulate matter ≤2.5 µm in aerodynamic diameter (PM_2.5) with 0.82% (95% CI: 0.38%-1.26%) at lag 06, respectively. Percentage increase for each 1 mg/m³ increase in CO was 5.99% (95% CI: 2.74%-9.34%) at lag 06. Further, stronger effects on COPD admissions were found in warm seasons than in cold seasons.

Conclusion

Short-term exposures to PM_2.5, PM₁₀, NO₂, SO₂, and CO had adverse effects on COPD hospitalizations in Beijing with different magnitudes and lag days.

Live Imaging of Label-Free Graphene Oxide Reveals Critical Factors Causing Oxidative-Stress-Mediated Cellular Responses

The interest in graphene and its translation into commercial products has been expanding at a high pace. Based on previously described pulmonary safety concerns for carbon nanomaterials, there is a great need to define parameters guiding interactions between graphene-based materials and the pulmonary system. The aim of the present study was to determine the importance of two critical parameters: lateral dimensions of the material and coating with proteins in relation to each other and their pulmonary impact. Endotoxin-free materials with distinct lateral dimensions, s-GO (50-200 nm) and l-GO (5-15 μm), were produced and thoroughly characterized. Exploiting intrinsic fluorescence of graphene oxide (GO) and using confocal live-cell imaging, the behavior of the cells in response to the material was visualized in real time. Although BEAS-2B cells internalized GO efficiently, l-GO was linked to higher plasma membrane interactions correlated with elevated reactive oxygen species (ROS) levels, pro-inflammatory response, and greater cytotoxicity, in agreement with the oxidative stress paradigm. For both GO types, the presence of serum alleviated lipid peroxidation of plasma membrane and decreased intracellular ROS levels. However, protein coating was not enough to entirely mitigate toxicity and inflammatory response induced by l-GO. In vitro results were validated in vivo, as l-GO was more prone to induce pulmonary granulomatous response in mice compared to s-GO. In conclusion, the lateral dimension of GO played a more important role than serum protein coating in determining biological responses to the material. It was also demonstrated that time-lapse imaging of live cells interacting with label-free GO sheets can be used as a tool to assess GO-induced cytotoxicity.

Lack of Association Between the IL1B (-511 and +3954), IL1RN VNTR Polymorphisms and Tuberculosis Risk: A Meta-analysis

BACKGROUND

Several recent studies have provided evidence that polymorphisms in the interleukin-1 (IL1) gene are implicated in tuberculosis (TB). However, results of different studies are inconsistent. The aim of this study was to perform a meta-analysis investigating the association of the IL1B (-511 and +3954) and IL1RN VNTR polymorphisms with TB risk.

METHODS

A systematic review of the English literature was conducted by searching Pubmed, Scopus, and ISI Web of Knowledge databases for relevant studies. Pooled odds ratios (OR) with 95 % confidence intervals (CI) were calculated using fixed effects models. Between-study heterogeneity and publication bias were also evaluated.

RESULTS

Nine case-control studies including 3327 participants were reviewed and analyzed. Our results did not indicate any association of the IL1B (-511 and +3954) and IL1RN VNTR polymorphisms with TB risk in the overall populations. The pooled OR of the IL1B -511 polymorphism was 1.09 (95 % CI 0.87-1.36) for the dominant model, 1.11 (0.89-1.38) for the recessive model, 1.15 (0.87-1.50) for the homozygote model, and 1.07 (0.94-1.23) for the allelic comparison model. ORs for the IL1B +3954 and IL1RN VNTR polymorphisms were similar. In subgroup analysis stratified by ethnicity, the results revealed no association between these polymorphisms and TB risk in black people, Asians, and Caucasians, respectively. We did not identify significant between-study heterogeneity across all studies, and there was no evidence of publication bias.

CONCLUSIONS

Our results indicate there is a lack of association between the IL1B (-511 and +3954), IL1RN VNTR polymorphisms and TB risk.

Indoor pollutant exposures modify the effect of airborne endotoxin on asthma in urban children

RATIONALE

The effect of endotoxin on asthma morbidity in urban populations is unclear.

OBJECTIVES

To determine if indoor pollutant exposure modifies the relationships between indoor airborne endotoxin and asthma health and morbidity.

METHODS

One hundred forty-six children and adolescents with persistent asthma underwent repeated clinical assessments at 0, 3, 6, 9, and 12 months. Home visits were conducted at the same time points for assessment of airborne nicotine, endotoxin, and nitrogen dioxide (NO2) concentrations. The effect of concomitant pollutant exposure on relationships between endotoxin and asthma outcomes were examined in stratified analyses and statistical models with interaction terms.

MEASUREMENTS AND MAIN RESULTS

Both air nicotine and NO2 concentrations modified the relationships between airborne endotoxin and asthma outcomes. Among children living in homes with no detectable air nicotine, higher endotoxin was inversely associated with acute visits and oral corticosteroid bursts, whereas among those in homes with detectable air nicotine, endotoxin was positively associated with these outcomes (interaction P value = 0.004 and 0.07, respectively). Among children living in homes with lower NO2 concentrations (<20 ppb), higher endotoxin was positively associated with acute visits, whereas among those living in homes with higher NO2 concentrations, endotoxin was negatively associated with acute visit (interaction P value = 0.05). NO2 also modified the effect of endotoxin on asthma symptom outcomes in a similar manner.

CONCLUSIONS

The effects of household airborne endotoxin exposure on asthma are modified by coexposure to air nicotine and NO2, and these pollutants have opposite effects on the relationships between endotoxin and asthma-related outcomes.

S100A9 promotes human lung fibroblast cells activation through receptor for advanced glycation end-product-mediated extracellular-regulated kinase 1/2, mitogen-activated protein-kinase and nuclear factor-κB-dependent pathways

S100A9 belongs to the S100 family of calcium-binding proteins and plays a key role in many inflammatory conditions. Recent studies have found that S100A9 was elevated significantly in the bronchoalveolar lavage fluid of idiopathic pulmonary fibrosis patients, and might be a biomarker for fibrotic interstitial lung diseases. However, the exact function of S100A9 in pulmonary fibrosis needs further studies. We performed this study to investigate the effect of S100A9 on human embryo lung fibroblast (HLF) proliferation and production of cytokines and collagen, providing new insights into the possible mechanism. S100A9 promoted proliferation of fibroblasts and up-regulated expression of both proinflammatory cytokines interleukin (IL)-6, IL-8, IL-1β and collagen type III. S100A9 also induced HLF cells to produce α-smooth muscle actin (α-SMA) and receptor for advanced glycation end-product (RAGE). In addition, S100A9 caused a significant increase in extracellular-regulated kinase (ERK)1/2 mitogen-activated protein kinase (MAPK) phosphorylation, while the status of p38 and c-Jun N-terminal kinase (JNK) phosphorylation remained unchanged. Treatment of cells with S100A9 also enhanced nuclear factor kappa B (NF-κB) activation. RAGE blocking antibody pretreatment inhibited the S100A9-induced cell proliferation, cytokine production and pathway phosphorylation. S100A9-mediated cell activation was suppressed significantly by ERK1/2 MAPK inhibitor and NF-κB inhibitor. In conclusion, S100A9 promoted HLF cell growth and induced cells to secret proinflammatory cytokines and collagen through RAGE signalling and activation of ERK1/2 MAPK and NF-κB pathways.

Modulatory effects of ozone on THP-1 cells in response to SP-A stimulation

Ozone (O(3)), a major component of air pollution and a strong oxidizing agent, can lead to lung injury associated with edema, inflammation, and epithelial cell damage. The effects of O(3) on pulmonary immune cells have been studied in various in vivo and in vitro systems. We have shown previously that O(3) exposure of surfactant protein (SP)-A decreases its ability to modulate proinflammatory cytokine production by cells of monocyte/macrophage lineage (THP-1 cells). In this report, we exposed THP-1 cells and/or native SP-A obtained from bronchoalveolar lavage of patients with alveolar proteinosis to O(3) and studied cytokine production and NF-kappaB signaling. The results showed 1) exposure of THP-1 cells to O(3) significantly decreased their ability to express TNF-alpha in response to SP-A; TNF-alpha production, under these conditions, was still significantly higher than basal (unstimulated) levels in filtered air-exposed THP-1 cells; 2) exposure of both THP-1 cells and SP-A to O(3) did not result in any significant differences in TNF-alpha expression compared with basal levels; 3) O(3) exposure of SP-A resulted in a decreased ability of SP-A to activate the NF-kappaB pathway, as assessed by the lack of significant increase and decrease of the nuclear p65 subunit of NF-kappaB and cytoplasmic IkappaBalpha, respectively; and 4) O(3) exposure of THP-1 cells resulted in a decrease in SP-A-mediated THP-1 cell responsiveness, which did not seem to be mediated via the classic NF-kappaB pathway. These findings indicate that O(3) exposure may mediate its effect on macrophage function both directly and indirectly (via SP-A oxidation) and by involving different mechanisms.

Shift toward an alternatively activated macrophage response in lungs of NO2-exposed rats

Inflammatory mechanisms are thought to play an important role in the pathogenesis of acute and chronic obstructive pulmonary diseases. In a rat inhalation model using continuous exposure to 10 ppm nitrogen dioxide for 1, 3, and 20 d, we investigated the inflammatory response with particular focus on the activation state of alveolar macrophages. Whereas the number of inflammatory cells and total protein concentration were increased in the bronchoalveolar lavage (BAL), the amount of the proinflammatory cytokine tumor necrosis factor-alpha was markedly reduced with increasing exposure time. In contrast, interleukin (IL)-10 and IL-6 were found at elevated levels and intracellular amounts of suppressor of cytokine signaling-3 protein increased in BAL cells. Upon in vitro lipopolysaccharide stimulation, BAL cells revealed reduced capability to produce the proinflammatory mediators tumor necrosis factor-alpha, IL-1 beta, and nitric oxide, but showed markedly increased transcription and protein release for IL-10. In addition, elevated levels of IL-6, scavenger receptor B, and suppressor of cytokine signaling-3 mRNA were detected in BAL cells from exposed animals. Analyses of highly purified alveolar macrophages indicated that changes in the activation state of these cells were responsible for the observed effects. In conclusion, a priming toward development of the alternatively activated macrophage phenotype occurred in the lungs of rats following nitrogen dioxide inhalation.

Air pollution and infection in respiratory illness

The detrimental effects of air pollution on health have been recognized for most of the last century. Effective legislation has led to a change in the nature of the air pollutants in outdoor air in developed countries, while combustion of raw fuels in the indoor environment remains a major health hazard in developing countries. The mechanisms of how these pollutants exert their effects are likely to be different, but there is emerging evidence that the toxic effects of new photochemical pollutants such as nitrogen dioxide are likely to be related to infection. This review discusses the relationship between air pollution and infection and will explore some of the mechanisms of how both could act synergistically to cause respiratory illnesses especially in exacerbating symptoms in individuals with pre-existing respiratory conditions such as asthma and chronic obstructive pulmonary disease.

Interference of a short-term exposure to nitrogen dioxide with allergic airways responses to allergenic challenges in BALB/c mice

Nitrogen dioxide (NO(2)) is a common indoor and outdoor air pollutant whose role in the induction of asthma is unclear. We investigated the effects of NO(2) on the development of asthma-like responses to allergenic challenge in BALB/c mice. Ovalbumin (OVA)-immunized mice were intranasally challenged with OVA or saline solution just before starting a 3 h exposure to 5 or 20 ppm NO(2) or air. Twenty parts per million of NO(2) induced a significant increase of bronchopulmonary hyperreactivity in OVA-challenged mice and of permeability according to the fibronectin content of the bronchoalveolar lavage fluid (BALF) 24 h after exposure, as compared with air or 5 ppm NO(2). Eosinophilia (cell counts in the BALF and eosinophil peroxidase of lung tissue) was detected at 24 and 72 h with similar levels for air and 20 ppm NO(2), whereas a marked reduction was unexpectedly observed for 5 ppm NO(2). At 24 h, interleukin-5 in the BALF was markedly reduced at 5 ppm compared with 20 ppm NO(2) and was also more intense for 20 ppm NO(2) than for the air group. In contrast to specific IgG1 titers, anti-OVA IgE titers and interleukin-4 in the BALF were not affected by NO(2) exposure. Irrespective of the concentration of NO(2), OVA-challenged mice did not develop late mucosal metaplasia compared with those exposed to OVA-air. These results indicate that a short exposure to NO(2) can exacerbate or inhibit some features of the development of allergic disease in mice and may depend on the concentration of pollutant.

Activation of alveolar macrophages in lung injury associated with experimental acute pancreatitis is mediated by the liver

OBJECTIVE

To evaluate (1) whether alveolar macrophages are activated as a consequence of acute pancreatitis (AP), (2) the implication of inflammatory factors released by these macrophages in the process of neutrophil migration into the lungs observed in lung injury induced by AP, and (3) the role of the liver in the activation of alveolar macrophages.

SUMMARY BACKGROUND DATA

Acute lung injury is the extrapancreatic complication most frequently associated with death and complications in severe AP. Neutrophil infiltration into the lungs seems to be related to the release of systemic and local mediators. The liver and alveolar macrophages are sources of mediators that have been suggested to participate in the lung damage associated with AP.

METHODS

Pancreatitis was induced in rats by intraductal administration of 5% sodium taurocholate. The inflammatory process in the lung and the activation of alveolar macrophages were investigated in animals with and without portocaval shunting 3 hours after AP induction. Alveolar macrophages were obtained by bronchoalveolar lavage. The generation of nitric oxide, leukotriene B4, tumor necrosis factor-alpha, and MIP-2 by alveolar macrophages and the chemotactic activity of supernatants of cultured macrophages were evaluated.

RESULTS

Pancreatitis was associated with increased infiltration of neutrophils into the lungs 3 hours after induction. This effect was prevented by the portocaval shunt. Alveolar macrophages obtained after induction of pancreatitis generated increased levels of nitric oxide, tumor necrosis factor-alpha, and MIP-2, but not leukotriene B4. In addition, supernatants of these macrophages exhibited a chemotactic activity for neutrophils when instilled into the lungs of unmanipulated animals. All these effects were abolished when portocaval shunting was carried out before induction of pancreatitis.

CONCLUSION

Lung damage induced by experimental AP is associated with alveolar macrophage activation. The liver mediates the alveolar macrophage activation in this experimental model.