Interplay of Cytokines and Chemokines in Aspergillosis

Aspergillosis is a fungal infection caused by various species of Aspergillus, most notably A. fumigatus. This fungus causes a spectrum of diseases, including allergic bronchopulmonary aspergillosis, aspergilloma, chronic pulmonary aspergillosis, and invasive aspergillosis. The clinical manifestations and severity of aspergillosis can vary depending on individual immune status and the specific species of Aspergillus involved. The recognition of Aspergillus involves pathogen-associated molecular patterns (PAMPs) such as glucan, galactomannan, mannose, and conidial surface proteins. These are recognized by the pathogen recognition receptors present on immune cells such as Toll-like receptors (TLR-1,2,3,4, etc.) and C-type lectins (Dectin-1 and Dectin-2). We discuss the roles of cytokines and pathogen recognition in aspergillosis from both the perspective of human and experimental infection. Several cytokines and chemokines have been implicated in the immune response to Aspergillus infection, including interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), CCR4, CCR17, and other interleukins. For example, allergic bronchopulmonary aspergillosis (ABPA) is characterized by Th2 and Th9 cell-type immunity and involves interleukin (IL)-4, IL-5, IL-13, and IL-10. In contrast, it has been observed that invasive aspergillosis involves Th1 and Th17 cell-type immunity via IFN-γ, IL-1, IL-6, and IL-17. These cytokines activate various immune cells and stimulate the production of other immune molecules, such as antimicrobial peptides and reactive oxygen species, which aid in the clearance of the fungal pathogen. Moreover, they help to initiate and coordinate the immune response, recruit immune cells to the site of infection, and promote clearance of the fungus. Insight into the host response from both human and animal studies may aid in understanding the immune response in aspergillosis, possibly leading to harnessing the power of cytokines or cytokine (receptor) antagonists and transforming them into precise immunotherapeutic strategies. This could advance personalized medicine.

IL-9 blockade attenuates inflammation in a murine model of mechanical ventilation-induced lung injury by inhibiting the NLRP3 inflammasome pathway

OBJECTIVES

Ventilation-induced lung injury (VILI) causes a huge economic and social burden, and its prevention and treatment have gained increasing attention in recent years. IL-9 is an important inflammatory factor, but its potential role in VILI remains unclear. This study intended to explore whether blocking IL-9 could alleviate VILI and explore its underlying mechanism.

METHODS

Lung injury was induced by mechanical ventilation (MV) in C57BL/6 mice. Changes in inflammatory factors and NLRP3-related proteins were assessed using quantitative reverse transcription-polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay. Subsequently, Nlrp3^-/- mice were used to further elucidate the underlying mechanism.

RESULTS

The percentage of Th9 cells in the peripheral blood, bronchoalveolar lavage fluid (BALF), and lung tissues of MV mice was increased compared to those of control mice. Treatment with anti-IL-9 mAb significantly alleviated the changes in lung histopathology, wet/dry lung proportion, total protein content, and neutrophil content in BALF induced by VILI. Additionally, administering anti-IL-9 mAb significantly downregulated the expression levels of inflammatory factors in BALF and lung tissues of mice with VILI. In addition, administering anti-IL-9 mAb inhibited NLRP3 inflammasome activation, as evidenced by the observed downregulation of NLRP3, ASC, cleaved caspase-1, and GSDMD-N. Additionally, NLRP3-deficient mice had lower lung injury induced by VILI than wild-type mice. Furthermore, the anti-IL-9 mAb only partially inhibited VILI in Nlrp3^-/- mice.

CONCLUSIONS

In MV mice, the anti-IL-9 mAb alleviated lung injury and reduced the secretion and expression of inflammatory factors partly by inhibiting the NLRP3 inflammasome pathway.

Recent Insights into Human Endometrial Peptidases in Blastocyst Implantation via Shedding of Microvesicles

Blastocyst implantation involves multiple interactions with numerous molecules expressed in endometrial epithelial cells (EECs) during the implantation window; however, there is limited information regarding the molecular mechanism underlying the crosstalk. In blastocysts, fibronectin plays a major role in the adhesion of various types of cells by binding to extracellular matrix proteins via the Arg-Gly-Asp (RGD) motif. In EECs, RGD-recognizing integrins are important bridging receptors for fibronectin, whereas the non-RGD binding of fibronectin includes interactions with dipeptidyl peptidase IV (DPPIV)/cluster of differentiation (CD) 26. Fibronectin may also bind to aminopeptidase N (APN)/CD13, and in the endometrium, these peptidases are present in plasma membranes and lysosomal membranes. Blastocyst implantation is accompanied by lysosome exocytosis, which transports various peptidases and nutrients into the endometrial cavity to facilitate blastocyst implantation. Both DPPIV and APN are released into the uterine cavity via shedding of microvesicles (MVs) from EECs. Recently, extracellular vesicles derived from endometrial cells have been proposed to act on trophectoderm cells to promote implantation. MVs are also secreted from embryonal stem cells and may play an active role in implantation. Thus, crosstalk between the blastocyst and endometrium via extracellular vesicles is a new insight into the fundamental molecular basis of blastocyst implantation.

Mesenchymal stem cell and endothelial progenitor cells coinjection improves LPS-induced lung injury via Tie2 activation and downregulation of the TLR4/MyD88 pathway

Sepsis is one of the most important complications of infection with a high mortality rate. Recently, cell therapy has been widely used to reduce the symptoms of sepsis. It has been previously reported that mesenchymal stem cell (MSC) and endothelial progenitor cells (EPC) therapy have beneficial effects in experimental models of sepsis. The effects of coculture of MSC and EPC have not yet been used to treat sepsis. Therefore, the aim of this study was to investigate the therapeutic potential of EPC + MSC coculture on the residual effects of sepsis in a lipopolysaccharide (LPS)-induced mice model. Coinjections of EPC + MSC significantly enhanced the survival rate of LPS-induced mice, decreased concentrations of pro-inflammatory cytokines, and increased the level of anti-inflammatory cytokine. The LPS-induced mice that were treated with EPC + MSC showed a notable reduction in pulmonary edema, hepatic enzymes, and C-reactive protein level compared with the control group. Our results showed that coinjection of EPC + MSC up and downregulates Tie2 and TLR4/MyD88 signaling pathways in LPS-induced mice, respectively. Also, in vitro study showed that viability, adhesion, and migration in coculture cells is significantly decreased after being induced with 10 μg/ml LPS. Our results showed that LPS impaired the functional activity of the cocultured EPC + MSC via upregulation of the TLR4/MyD88 signaling pathway, which may be associated with decreased pTie2/Tie2 expression. In conclusion, coinjection of EPC and MSC modulated the TLR4/MyD88 signaling pathway that leads to reduce the inflammatory response. This study may provide promising results for the introduction of cocultured cells to manage infectious diseases and balance the immune response through immune regulatory function.

Creatine Supply Attenuates Ischemia-Reperfusion Injury in Lung Transplantation in Rats

Ischemia-reperfusion injury (IRI) is one of the factors limiting the success of lung transplantation (LTx). IRI increases death risk after transplantation through innate immune system activation and inflammation induction. Some studies have shown that creatine (Cr) protects tissues from ischemic damage by its antioxidant action. We evaluated the effects of Cr supplementation on IRI after unilateral LTx in rats. Sixty-four rats were divided into four groups: water + 90 min of ischemia; Cr + 90 min of ischemia; water + 180 min of ischemia; and Cr + 180 min of ischemia. Donor animals received oral Cr supplementation (0.5 g/kg/day) or vehicle (water) for five days prior to LTx. The left lung was exposed to cold ischemia for 90 or 180 min, followed by reperfusion for 2 h. We evaluated the ventilatory mechanics and inflammatory responses of the graft. Cr-treated animals showed a significant decrease in exhaled nitric oxide levels and inflammatory cells in blood, bronchoalveolar lavage fluid and lung tissue. Moreover, edema, cell proliferation and apoptosis in lung parenchyma were reduced in Cr groups. Finally, TLR-4, IL-6 and CINC-1 levels were lower in Cr-treated animals. We concluded that Cr caused a significant decrease in the majority of inflammation parameters evaluated and had a protective effect on the IRI after LTx in rats.

Alterations in the Gut Microbiome and Cecal Metabolome During Klebsiella pneumoniae-Induced Pneumosepsis

Klebsiella (K.) pneumoniae is a common cause of pneumonia-derived sepsis in human and is associated with high morbidity and mortality. The microbiota promotes and maintains host immune homeostasis during bacterial infections. However, the mechanisms by which the gut microbiota affects immune responses in the lung still remain poorly understood. Here, we performed cecal metabolomics sequencing and fecal 16s rRNA sequencing in K. pneumoniae-infected mice and uninfected controls and showed that K. pneumoniae infection led to profound alterations in the gut microbiome and thus the cecal metabolome. We observed that the levels of Lactobacillus reuteri and Bifidobacterium pseudolongum were significantly decreased in K. pneumoniae-infected mice. Spearman correlation analysis showed that alterations in the richness and composition of the gut microbiota were associated with profound changes in host metabolite concentrations. Further, short-chain fatty acids (SCFAs), including acetate, propionate, and butyrate, were detected in cecal contents and serum by gas chromatography-mass spectrometry (GC-MS). We observed that the concentrations of these three SCFAs were all lower in the infected groups than in the untreated controls. Lastly, oral supplementation with these three SCFAs reduced susceptibility to K. pneumoniae infections, as indicated by lower bacterial burdens in the lung and higher survival rates. Our data highlight the protective roles of gut microbiota and certain metabolites in K. pneumoniae-pneumonia and suggests that it is possible to intervene in this bacterial pneumonia by targeting the gut microbiota.

Staphylococcus aureus Lung Infection Results in Down-Regulation of Surfactant Protein-A Mainly Caused by Pro-Inflammatory Macrophages

Pneumonia is the leading cause of hospitalization worldwide. Besides viruses, bacterial co-infections dramatically exacerbate infection. In general, surfactant protein-A (SP-A) represents a first line of immune defense. In this study, we analyzed whether influenza A virus (IAV) and/or Staphylococcus aureus (S. aureus) infections affect SP-A expression. To closely reflect the situation in the lung, we used a human alveolus-on-a-chip model and a murine pneumonia model. Our results show that S. aureus can reduce extracellular levels of SP-A, most likely attributed to bacterial proteases. Mono-epithelial cell culture experiments reveal that the expression of SP-A is not directly affected by IAV or S. aureus. Yet, the mRNA expression of SP-A is strongly down-regulated by TNF-α, which is highly produced by professional phagocytes in response to bacterial infection. By using the human alveolus-on-a-chip model, we show that the down-regulation of SP-A is strongly dependent on macrophages. In a murine model of pneumonia, we can confirm that S. aureus decreases SP-A levels in vivo. These findings indicate that (I) complex interactions of epithelial and immune cells induce down-regulation of SP-A expression and (II) bacterial mono- and super-infections reduce SP-A expression in the lung, which might contribute to a severe outcome of bacterial pneumonia.

Alpha-linolenic acid protects against lipopolysaccharide-induced acute lung injury through anti-inflammatory and anti-oxidative pathways

Alpha-linolenic acid (ALA), an important component of polyunsaturated fatty acids (PUFAs), possesses potent anti-inflammatory properties. To date, the effects of ALA on acute lung injury (ALI) remains unknown. This study was designed to investigate the potential protective effects of ALA on LPS-induced ALI and the underpinning mechanisms. An animal model of ALI was established via intratracheally injection of lipopolysaccharide (LPS, 1 mg/kg). We found that lung wet/dry weight ratio and protein concentration in Bronchoalveolar lavage fluid (BALF) were dramatically decreased by ALA pretreatment. Treatment with ALA significantly alleviated the infiltration of total cells and neutrophils, while increased the number of the macrophages. ALA significantly inhibited the secretion of proinflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) and increased anti-inflammatory cytokine. Moreover, we found that the levels of myeloperoxidase (MPO) and malondialdehyde (MDA) were highly increased in LPS-induced ALI, while the activities of glutathione (GSH) and superoxide dismutase (SOD) were decreased, which were reversed by ALA. ALA attenuated LPS-induced histopathological changes and apoptosis. Furthermore, ALA significantly inhibited the phosphorylation of IκBα and NF-κB (p65) activation in ALI. ALA showed anti-inflammatory effects in mice with LPS-induced ALI. NF-κB pathway may be involved in ALA mediated protective effects.

Dioscin alleviates lipopolysaccharide-induced acute lung injury through suppression of TLR4 signaling pathways

Aim: Acute lung injury (ALI) is a life-threatening inflammatory syndrome that lacks an effective therapy. Dioscin, a natural steroid saponin isolated from a variety of herbs, could serve as an anti-inflammatory agent, as suggested in previous reports. The purpose of this study was to explore the effects of dioscin on lipopolysaccharide (LPS)-induced ALI and validate the potential mechanisms.Materials and Methods: An ALI model was induced by intratracheal administration of LPS. Dioscin (20, 40, and 80 mg/kg) was administered intragastrically once daily for seven consecutive days prior to LPS challenge.Results: Our data revealed that dioscin significantly suppressed LPS-induced lung pathological changes, pulmonary capillary permeability, pulmonary edema, inflammatory cell infiltration, myeloperoxidase (MPO) activity, and cytokine production, including tumor necrosis factor (TNF)-α, interleukin (IL)-6, and keratinocyte chemoattractant (KC). Moreover, dioscin inhibited LPS-induced nuclear factor-kappaB (NF-κB) activation as well as Toll-like receptor 4 (TLR4) expression.Conclusions: In brief, the results indicated that dioscin alleviates LPS-induced ALI through suppression of TLR4 signaling pathways.

Pulmonary protection of transcutaneous electrical acupoint stimulation in gynecological laparoscopic surgery: A randomized controlled trial

Laparoscopy is performed worldwide due to its limited side effects and optimal treatment efficacy. However, it also has adverse effects, including atelectasis and ischemia-reperfusion injury, due to CO₂ accumulation during ventilation in a head-down position, which may result in severe disorders and adversely affecting postoperative recovery, prolonging hospitalization. The present study was performed to assess whether transcutaneous electrical acupoint stimulation (TEAS) protects against lung injury occurring during gynecological laparoscopic surgery. Patients were randomly allocated to two groups: Control group (received no stimulation) and TEAS group (patients treated with TEAS on BL13, LI4 and LU5). The mean arterial pressure, heart rate and oxygen saturation were recorded at the time-points of arriving in the operating room (T₀), immediately prior to induction of the pneumoperitoneum (T₁), immediately after the end of pneumoperitoneum (T₂) and on leaving the operating room (T₃). Arterial blood gas analysis was performed to record the pH, determine the partial pressure of carbon dioxide and calculate the oxygenation index (OI) at T_0–3. Blood samples were taken from the peripheral vein for determination of the serum concentrations of tumor necrosis factor (TNF)-α and interleukin (IL)-1β at T₀ and T₃. Post-operative pulmonary complications occurring during the first five days after surgery were also recorded. A total of 100 patients were initially enrolled and 80 patients were analysed. The results indicated that the OI in the control group was significantly lower than that in the TEAS group at the T₂ and T₃ time-points. The serum concentrations of TNF-α and IL-1β were significantly increased following surgery, while the extent of these increases was lower in the TEAS group compared with that in the control group. The incidence of post-operative pulmonary complications was significantly lower in the TEAS group. It was therefore indicated that TEAS protect against lung injury as a complication of gynecological laparoscopic surgery. The present study was registered at http://www.clinicaltrials.gov prior to enrollment of the patients (no. NCT02850471).

Multiple exposures to poultry barn air and lipopolysaccharide synergistically increase the pulmonary expression of TLR-4 and IL-1β

Objective

Poultry farm workers are exposed to barn air and suffer from various respiratory disorders. Due to frequent prevalence of endotoxin in the farm settings workers can get co‐exposed to barn air and endotoxin. The study was aimed to explore the pulmonary damage following long‐term multiple exposures to poultry barn air with or without endotoxin.

Methods

We studied the pulmonary expression of Toll‐like receptor 4 (TLR4) and Interleukin‐1β (IL‐1β) by exposing Swiss albino mice to poultry barn air for 6 days (Monday‐Saturday) in a week for 5 and 10 weeks. At the end of exposure, animals were challenged with lipopolysaccharide (LPS) or normal saline solution @80 μg/mouse intranasally. Histopathology, bronchoalveolar lavage (BAL) fluid and blood analysis were used to characterize lung damage. mRNA and protein expression of TLR4 and IL‐1β were evaluated using quantitative polymerase chain reaction (qPCR) and immunohistochemistry, respectively.

Results

Histopathology along with TLC and DLC of blood and BAL fluid revealed lung damage following multiple exposures and damage was severe in combination with LPS. Exposures altered mRNA and protein expression of TLR‐4 and IL‐1β and the expression was more marked following 30 days of exposure. Further LPS co‐challenge showed a synergistic effect on the expression of TLR4 and IL‐1β.

Conclusions

The data suggest that long‐term exposures with or without LPS caused lung damage and altered the pulmonary expression of TLR4 and IL‐1β.

Lung infection caused by Pseudomonas aeruginosa in a CD26/DPP4 deficient F344 rat model

Background

Pseudomonas aeruginosa (PA) is the most important opportunistic pathogen in causing nosocomial infections and, furthermore, poses a permanent threat for severe chronic infections in patients with cystic fibrosis or COPD. The transmembrane protein CD26 with dipeptidyl peptidase-4 (DPP4) activity shows an increased expression in inflamed tissue. We tested whether CD26/DPP4 deficiency leads to reduced inflammation and decreased structural damage when infected with PA.

Methods

CD26/DPP4⁺ and CD26/DPP4⁻ rats were instilled intratracheally with NaCl (controls) or with PA. Six hours later, bacterial distribution was detected with the in vivo imaging system 200 (IVIS). Lungs were then processed for molecular biology, light and electron microscopy and analyzed qualitatively, quantitatively and stereologically. Bacterial numbers were determined in homogenized lungs.

Results

Compared to saline treated controls, in both infected groups (1) the acinar airspace was significantly increased, (2) the volume density of the alveolar epithelium was significantly decreased, (3) the septal thickness was significantly reduced, (4) more than 40% of the alveolar epithelial surface was damaged, and up to 36% of the epithelial surface was covered with edema. In infected CD26⁻ rats, the increase in lung weight was significantly less pronounced, the portion of edematous alveolar airspace was significantly lower and the part of edema interspersed with PA was decreased significantly.

Conclusions

CD26/DPP4 deficiency resulted in reduced pulmonary edema under sublethal PA infection, implicating a role for CD26 in infection progression. The partly pronounced structural damage may mask further possible influences of CD26 on the inflammatory response.

Bronchopulmonary dysplasia: Pathogenesis and treatment

Bronchopulmonary dysplasia (BPD) is a form of chronic lung disease of infancy, which mostly affects premature infants with significant morbidity and mortality. Premature infants who require to be treated for conditions including respiratory distress syndrome have a higher risk of developing BPD. In spite of the improvement in clinical methods, the incidence of BPD has not reduced. In the present review, the pathogenesis of BPD is described along with the treatments available at present and the role of nursing in the management of BPD. Emerging preventive therapies for BPD are also discussed, including the use of recombinant human superoxide dismutase, which has been proven effective in reducing respiratory injury and its long-term effects.

Host transcriptional responses following ex vivo re-challenge with Mycobacterium tuberculosis vary with disease status

The identification of immune correlates that are predictive of disease outcome for tuberculosis remains an ongoing challenge. To address this issue, we evaluated gene expression profiles from peripheral blood mononuclear cells following ex vivo challenge with Mycobacterium tuberculosis, among participants with active TB disease (ATBD, n = 10), latent TB infection (LTBI, n = 10), and previous active TB disease (after successful treatment; PTBD, n = 10), relative to controls (n = 10). Differential gene expression profiles were assessed by suppression-subtractive hybridization, dot blot, real-time polymerase chain reaction, and the comparative cycle threshold methods. Comparing ATBD to control samples, greater fold-increases of gene expression were observed for a number of chemotactic factors (CXCL1, CXCL3, IL8, MCP1, MIP1α). ATBD was also associated with higher IL1B gene expression, relative to controls. Among LTBI samples, gene expression of several chemotactic factors (CXCL2, CXCL3, IL8) was similarly elevated, compared to individuals with PTBD. Our results demonstrated that samples from participants with ATBD and LTBI have distinct gene expression profiles in response to ex vivo M. tuberculosis infection. These findings indicate the value in further characterizing the peripheral responses to M. tuberculosis challenge as a route to defining immune correlates of disease status or outcome.

A Comparative Study of Lung Host Defense in Murine Obesity Models. Insights into Neutrophil Function

We have shown that obesity-associated attenuation of murine acute lung injury is driven, in part, by blunted neutrophil chemotaxis, yet differences were noted between the two models of obesity studied. We hypothesized that obesity-associated impairment of multiple neutrophil functions contributes to increased risk for respiratory infection but that such impairments may vary between murine models of obesity. We examined the most commonly used murine obesity models (diet-induced obesity, db/db, CPE(fat/fat), and ob/ob) using a Klebsiella pneumoniae pneumonia model and LPS-induced pneumonitis. Marrow-derived neutrophils from uninjured lean and obese mice were examined for in vitro functional responses. All obesity models showed impaired clearance of K. pneumoniae, but in differing temporal patterns. Failure to contain infection in obese mice was seen in the db/db model at both 24 and 48 hours, yet this defect was only evident at 24 hours in CPE(fat/fat) and ob/ob models, and at 48 hours in diet-induced obesity. LPS-induced airspace neutrophilia was decreased in all models, and associated with blood neutropenia in the ob/ob model but with leukocytosis in the others. Obese mouse neutrophils from all models demonstrated impaired chemotaxis, whereas neutrophil granulocyte colony-stimulating factor-mediated survival, LPS-induced cytokine transcription, and mitogen-activated protein kinase and signal transducer and activator of transcription 3 activation in response to LPS and granulocyte colony-stimulating factor, respectively, were variably impaired across the four models. Obesity-associated impairment of host response to lung infection is characterized by defects in neutrophil recruitment and survival. However, critical differences exist between commonly used mouse models of obesity and may reflect variable penetrance of elements of the metabolic syndrome, as well as other factors.

Rapid DNA vaccination against Burkholderia pseudomallei flagellin by tattoo or intranasal application

Melioidosis is a severe infectious disease with a high mortality that is endemic in South-East Asia and Northern Australia. The causative pathogen, Burkholderia pseudomallei, is listed as potential bioterror weapon due to its high virulence and potential for easy dissemination. Currently, there is no licensed vaccine for prevention of melioidosis. Here, we explore the use of rapid plasmid DNA vaccination against B. pseudomallei flagellin for protection against respiratory challenge. We tested three flagellin DNA vaccines with different subcellular targeting designs. C57BL/6 mice were vaccinated via skin tattoo on day 0, 3 and 6 before intranasal challenge with B. pseudomallei on day 21. Next, the most effective construct was used as single vaccination on day 0 by tattoo or intranasal formulation. Mice were sacrificed 72 hours post-challenge to assess bacterial loads, cytokine responses, inflammation and microscopic lesions. A construct encoding a cellular secretion signal resulted in the most effective protection against melioidosis via tattooing, with a 10-fold reduction in bacterial loads in lungs and distant organs compared to the empty vector. Strikingly, a single intranasal administration of the same vaccine resulted in >1000-fold lower bacterial loads and increased survival. Pro-inflammatory cytokine responses were significantly diminished and strong reductions in markers for distant organ damage were observed. A rapid vaccination scheme using flagellin DNA tattoo provides significant protection against intranasal challenge with B. pseudomallei, markedly improved by a single administration via airway mucosa. Hence intranasal vaccination with flagellin-encoding DNA may be applicable when acute mass vaccination is indicated and warrants further testing.

Synergistic Effect of Hyperoxia and Biotrauma On Ventilator-Induced Lung Injury

Patients undergoing mechanical ventilation in intensive care units (ICUs) may develop ventilator-induced lung injury (VILI). Beside the high tidal volume (Vt) and plateau pressure (Pplat), hyperoxia is supposed to precipitate lung injury. Oxygen toxicity is presumed to occur at levels of fraction of inspired oxygen (FiO2) exceeding 0.40. The exposure time to hyperoxia is certainly very important and patients who spend extended time on mechanical ventilation (MV) are probably more exposed to severe hyperoxic acute lung injury (HALI). Together, hyperoxia and biotrauma (release of cytokines) have a synergistic effect and can induce VILI. In the clinical practice, the reduction of FiO2 to safe levels through the appropriate use of the positive end expiratory pressure (PEEP) and the alignment of mean airway pressure is an appropriate goal. The strategy for lung protective ventilation must include setting up FiO2 to a safe level that is accomplished by using PaO2/FiO2 ratio with a lower limit of FiO2 to achieve acceptable levels of PaO2, which will be safe for the patient without local (lungs) or systemic inflammatory response. The protocol from the ARDS-net study is used for ventilator setup and adjustment. Cytokines (IL-1, IL-6, TNFα and MIP-2) that are involved in the inflammatory response are determined in order to help the therapeutic approach in counteracting HALI. Computed tomography findings reflect the pathological phases of the diffuse alveolar damage. At least preferably the lowest level of FiO2 should be used in order to provide full lung protection against the damage induced by MV.

The effect of size-segregated ambient particulate matter on Th1/Th2-like immune responses in mice

Background

Particulate matter (PM) has been associated with increased pulmonary and cardiovascular mortality and morbidity. Additionally, PM is known to exacerbate asthma. However, whether ambient PM exposure contributes to the onset of asthma, especially in non-atopic children and adults, is less conclusive. The current study aimed to evaluate the effects of size-fractioned PM on lung immune responses in healthy BALB/c mice.

Methods and principal findings

We collected PM₁₀, PM_2.5, PM₁ and PM_0.1 samples from October 2012 to August 2013 in the Taipei Basin. These PM samples were representative of urban traffic pollution. The samples were extracted and sonicated in phosphate-buffered saline (PBS). Female BALB/c mice were exposed to the samples via intratracheal instillation at three different doses: 1.75 mg/kg (35 μg/per mouse), 5 mg/kg (100 μg/per mouse), and 12.5 mg/kg (250 μg/per mouse). The mice were exposed on days 0 and 7, and PBS alone was used as a control. Following the exposures, the expression profiles of inflammatory cells and cytokines in bronchoalveolar lavage fluid (BALF) were assessed. Exposure to PM₁₀ resulted in inflammatory responses, including the recruitment of neutrophils and the induction of T helper 1 (Th1) cell-related cytokine release, such as TNF-α and IFN-γ. Furthermore, an allergic immune response, including the recruitment of eosinophils and the up-regulation of T helper 2 (Th2) cell-related cytokine release, such as IL-5 and IL-13, was also observed in the BALF of mice exposed to PM₁₀.

Conclusions

Our study showed that exposure to PM alone caused mixed Th1/Th2 inflammatory responses in healthy mice. These findings support the hypothesis that PM may contribute to the onset of asthma.

Mycobacterium tuberculosis-triggered Hippo pathway orchestrates CXCL1/2 expression to modulate host immune responses

Mycobacterium tuberculosis (Mtb) pathogenesis encompasses a plethora of finely regulated alterations within the host which eventually coin the outcome of infection. Chemokines are important components in directing immune cell recruitment to the site of infection, and shaping the disease progression. Here, we demonstrate that Hippo (mammalian sterile 20-like 1 and 2 kinases, MST1/2, in mammals), is activated during mycobacterial infection in a toll-like receptor (TLR) 2-interleukin receptor-1 associated kinases (IRAK1/4)-dependent manner. Mtb-triggered Hippo signaling modulates the expression and secretion of chemokines (CXCL1 and CXCL2); as silencing MST1/2 compromised the ability of Mtb to furnish the same. Further insight into the mechanism of Hippo-mediated regulation of chemokines revealed the role for a non-canonical Hippo effector interferon (IFN) regulatory factor (IRF) 3 in the process and marked the effect to be independent of LATS1. Alongside their ability to guide directed recruitment of immune cells, we have uncovered a paracrine role for Hippo-mediated secretion of CXCL1 and CXCL2 in the production of anti-microbial peptides (beta-defensins), iNOS, NOX2 and pro-inflammatory molecules during mycobacterial infection of the host. This study highlights the involvement of TLR2-IRAK1/4-MST1/2-IRF3 axis in Mtb-triggered modulation of chemokines and identifies Hippo signaling as a novel regulator of host-mycobacterial interactions.

Inhibition of endotoxin-induced airway epithelial cell injury by a novel family of pyrrol derivates

Inflammation and apoptosis are crucial mechanisms for the development of the acute respiratory distress syndrome (ARDS). Currently, there is no specific pharmacological therapy for ARDS. We have evaluated the ability of a new family of 1,2,3,5-tetrasubstituted pyrrol compounds for attenuating lipopolysaccharide (LPS)-induced inflammation and apoptosis in an in vitro LPS-induced airway epithelial cell injury model based on the first steps of the development of sepsis-induced ARDS. Human alveolar A549 and human bronchial BEAS-2B cells were exposed to LPS, either alone or in combination with the pyrrol derivatives. Rhein and emodin, two representative compounds with proven activity against the effects of LPS, were used as reference compounds. The pyrrol compound that was termed DTA0118 had the strongest inhibitory activity and was selected as the lead compound to further explore its properties. Exposure to LPS caused an intense inflammatory response and apoptosis in both A549 and BEAS-2B cells. DTA0118 treatment downregulated Toll-like receptor-4 expression and upregulated nuclear factor-κB inhibitor-α expression in cells exposed to LPS. These anti-inflammatory effects were accompanied by a significantly lower secretion of interleukin-6 (IL-6), IL-8, and IL-1β. The observed antiapoptotic effect of DTA0118 was associated with the upregulation of antiapoptotic Bcl-2 and downregulation of proapoptotic Bax and active caspase-3 protein levels. Our findings demonstrate the potent anti-inflammatory and antiapoptotic properties of the pyrrol DTA0118 compound and suggest that it could be considered as a potential drug therapy for the acute phase of sepsis and septic ARDS. Further investigations are needed to examine and validate these mechanisms and effects in a clinically relevant animal model of sepsis and sepsis-induced ARDS.

The gut microbiota plays a protective role in the host defence against pneumococcal pneumonia

OBJECTIVE

Pneumonia accounts for more deaths than any other infectious disease worldwide. The intestinal microbiota supports local mucosal immunity and is increasingly recognised as an important modulator of the systemic immune system. The precise role of the gut microbiota in bacterial pneumonia, however, is unknown. Here, we investigate the function of the gut microbiota in the host defence against Streptococcus pneumoniae infections.

DESIGN

We depleted the gut microbiota in C57BL/6 mice and subsequently infected them intranasally with S. pneumoniae. We then performed survival and faecal microbiota transplantation (FMT) experiments and measured parameters of inflammation and alveolar macrophage whole-genome responses.

RESULTS

We found that the gut microbiota protects the host during pneumococcal pneumonia, as reflected by increased bacterial dissemination, inflammation, organ damage and mortality in microbiota-depleted mice compared with controls. FMT in gut microbiota-depleted mice led to a normalisation of pulmonary bacterial counts and tumour necrosis factor-α and interleukin-10 levels 6 h after pneumococcal infection. Whole-genome mapping of alveolar macrophages showed upregulation of metabolic pathways in the absence of a healthy gut microbiota. This upregulation correlated with an altered cellular responsiveness, reflected by a reduced responsiveness to lipopolysaccharide and lipoteichoic acid. Compared with controls, alveolar macrophages derived from gut microbiota-depleted mice showed a diminished capacity to phagocytose S. pneumoniae.

CONCLUSIONS

This study identifies the intestinal microbiota as a protective mediator during pneumococcal pneumonia. The gut microbiota enhances primary alveolar macrophage function. Novel therapeutic strategies could exploit the gut-lung axis in bacterial infections.

The gut microbiota plays a protective role in the host defence against pneumococcal pneumonia

OBJECTIVE

Pneumonia accounts for more deaths than any other infectious disease worldwide. The intestinal microbiota supports local mucosal immunity and is increasingly recognised as an important modulator of the systemic immune system. The precise role of the gut microbiota in bacterial pneumonia, however, is unknown. Here, we investigate the function of the gut microbiota in the host defence against Streptococcus pneumoniae infections.

DESIGN

We depleted the gut microbiota in C57BL/6 mice and subsequently infected them intranasally with S. pneumoniae. We then performed survival and faecal microbiota transplantation (FMT) experiments and measured parameters of inflammation and alveolar macrophage whole-genome responses.

RESULTS

We found that the gut microbiota protects the host during pneumococcal pneumonia, as reflected by increased bacterial dissemination, inflammation, organ damage and mortality in microbiota-depleted mice compared with controls. FMT in gut microbiota-depleted mice led to a normalisation of pulmonary bacterial counts and tumour necrosis factor-α and interleukin-10 levels 6 h after pneumococcal infection. Whole-genome mapping of alveolar macrophages showed upregulation of metabolic pathways in the absence of a healthy gut microbiota. This upregulation correlated with an altered cellular responsiveness, reflected by a reduced responsiveness to lipopolysaccharide and lipoteichoic acid. Compared with controls, alveolar macrophages derived from gut microbiota-depleted mice showed a diminished capacity to phagocytose S. pneumoniae.

CONCLUSIONS

This study identifies the intestinal microbiota as a protective mediator during pneumococcal pneumonia. The gut microbiota enhances primary alveolar macrophage function. Novel therapeutic strategies could exploit the gut-lung axis in bacterial infections.

Innate Lymphocyte/Ly6C(hi) Monocyte Crosstalk Promotes Klebsiella Pneumoniae Clearance

Increasing antibiotic resistance among bacterial pathogens has rendered some infections untreatable with available antibiotics. Klebsiella pneumoniae, a bacterial pathogen that has acquired high-level antibiotic resistance, is a common cause of pulmonary infections. Optimal clearance of K. pneumoniae from the host lung requires TNF and IL-17A. Herein, we demonstrate that inflammatory monocytes are rapidly recruited to the lungs of K. pneumoniae-infected mice and produce TNF, which markedly increases the frequency of IL-17-producing innate lymphoid cells. While pulmonary clearance of K. pneumoniae is preserved in neutrophil-depleted mice, monocyte depletion or TNF deficiency impairs IL-17A-dependent resolution of pneumonia. Monocyte-mediated bacterial uptake and killing is enhanced by ILC production of IL-17A, indicating that innate lymphocytes engage in a positive-feedback loop with monocytes that promotes clearance of pneumonia. Innate immune defense against a highly antibiotic-resistant bacterial pathogen depends on crosstalk between inflammatory monocytes and innate lymphocytes that is mediated by TNF and IL-17A.

Receptor for Advanced Glycation End Products (RAGE) Serves a Protective Role during Klebsiella pneumoniae - Induced Pneumonia

Klebsiella species is the second most commonly isolated gram-negative organism in sepsis and a frequent causative pathogen in pneumonia. The receptor for advanced glycation end products (RAGE) is expressed on different cell types and plays a key role in diverse inflammatory responses. We here aimed to investigate the role of RAGE in the host response to Klebsiella (K.) pneumoniae pneumonia and intransally inoculated rage gene deficient (RAGE^-/-) and normal wild-type (Wt) mice with K. pneumoniae. Klebsiella pneumonia resulted in an increased pulmonary expression of RAGE. Furthermore, the high-affinity RAGE ligand high mobility group box-1 was upregulated during K. pneumoniae pneumonia. RAGE deficiency impaired host defense as reflected by a worsened survival, increased bacterial outgrowth and dissemination in RAGE^-/- mice. RAGE^-/- neutrophils showed a diminished phagocytosing capacity of live K. pneumoniae in vitro. Relative to Wt mice, RAGE^-/- mice demonstrated similar lung inflammation, and slightly elevated—if any—cytokine and chemokine levels and unchanged hepatocellular injury. In addition, RAGE^-/- mice displayed an unaltered response to intranasally instilled Klebsiella lipopolysaccharide (LPS) with respect to pulmonary cell recruitment and local release of cytokines and chemokines. These data suggest that (endogenous) RAGE protects against K. pneumoniae pneumonia. Also, they demonstrate that RAGE contributes to an effective antibacterial defense during K. pneumoniae pneumonia, at least partly via its participation in the phagocytic properties of professional granulocytes. Additionally, our results indicate that RAGE is not essential for the induction of a local and systemic inflammatory response to either intact Klebsiella or Klebsiella LPS.

Large area CMOS bio-pixel array for compact high sensitive multiplex biosensing

A novel CMOS bio-pixel array which integrates assay substrate and assay readout is demonstrated for multiplex and multireplicate detection of a triplicate of cytokines with single digit pg ml(-1) sensitivities. Uniquely designed large area bio-pixels enable individual assays to be dedicated to and addressed by single pixels. A capability to simultaneously measure a large number of targets is provided by the 128 available pixels. Chemiluminescent assays are carried out directly on the pixel surface which also detects the emitted chemiluminescent photons, facilitating a highly compact sensor and reader format. The high sensitivity of the bio-pixel array is enabled by the high refractive index of silicon based pixels. This in turn generates a strong supercritical angle luminescence response significantly increasing the efficiency of the photon collection over conventional farfield modalities.

Oropharyngeal aspiration of Burkholderia mallei and Burkholderia pseudomallei in BALB/c mice

Burkholderia mallei and Burkholderia pseudomallei are potentially lethal pathogens categorized as biothreat agents due, in part, to their ability to be disseminated via aerosol. There are no protective vaccines against these pathogens and treatment options are limited and cumbersome. Since disease severity is greatest when these agents are inhaled, efforts to develop pre- or post-exposure prophylaxis focus largely on inhalation models of infection. Here, we demonstrate a non-invasive and technically simple method for affecting the inhalational challenge of BALB/c mice with B. pseudomallei and B. mallei. In this model, two investigators utilized common laboratory tools such as forceps and a micropipette to conduct and characterize an effective and reproducible inhalational challenge of BALB/c mice with B. mallei and B. pseudomallei. Challenge by oropharyngeal aspiration resulted in acute disease. Additionally, 50% endpoints for B. pseudomallei K96243 and B. mallei ATCC 23344 were nearly identical to published aerosol challenge methods. Furthermore, the pathogens disseminated to all major organs typically targeted by these agents where they proliferated. The pro-inflammatory cytokine production in the proximal and peripheral fluids demonstrated a rapid and robust immune response comparable to previously described murine and human studies. These observations demonstrate that OA is a viable alternative to aerosol exposure.

Early activation of pro-fibrotic WNT5A in sepsis-induced acute lung injury

INTRODUCTION

The mechanisms of lung repair and fibrosis in the acute respiratory distress syndrome (ARDS) are poorly known. Since the role of WNT/β-catenin signaling appears to be central to lung healing and fibrosis, we hypothesized that this pathway is activated very early in the lungs after sepsis.

METHODS

We tested our hypothesis using a three-step experimental design: (1) in vitro lung cell injury model with human bronchial epithelial BEAS-2B and lung fibroblasts (MRC-5) cells exposed to endotoxin for 18 hours; (2) an animal model of sepsis-induced ARDS induced by cecal ligation and perforation, and (3) lung biopsies from patients who died within the first 24 hours of septic ARDS. We examined changes in protein levels of target genes involved in the Wnt pathway, including WNT5A, non-phospho (Ser33/37/Thr41) β-catenin, matrix metalloproteinase-7 (MMP7), cyclin D1, and vascular endothelial growth factor (VEGF) by Western blotting and immunohistochemistry. Finally, we validated the main gene targets of this pathway in experimental animals and human lungs.

RESULTS

Protein levels of WNT5A, non-phospho (Ser33/37/Thr41) β-catenin, total β-catenin, MMP7, cyclin D1, and VEGF increased after endotoxin stimulation in BEAS-2B and MRC-5 cells. Lungs from septic animals and from septic humans demonstrated acute lung inflammation, collagen deposition, and marked increase of WNT5A and MMP7 protein levels.

CONCLUSIONS

Our findings suggest that the WNT/β-catenin signaling pathway is activated very early in sepsis-induced ARDS and could play an important role in lung repair and fibrosis. Modulation of this pathway might represent a potential target for treatment for septic and ARDS patients.

Neutrophil extracellular traps in the host defense against sepsis induced by Burkholderia pseudomallei (melioidosis)

Background

Neutrophil extracellular traps (NETs) are a central player in the host response to bacteria: neutrophils release extracellular DNA (nucleosomes) and neutrophil elastase to entrap and kill bacteria. We studied the role of NETs in Burkholderia pseudomallei infection (melioidosis), an important cause of Gram-negative sepsis in Southeast Asia.

Methods

In a prospective observational study, circulating nucleosomes and neutrophil elastase were assayed in 44 patients with Gram-negative sepsis caused by B. pseudomallei (melioidosis) and 82 controls. Functional assays included human neutrophil stimulation and killing assays and a murine model of B. pseudomallei infection in which NET function was compromised using DNase. Specified pathogen-free 8- to 12-week-old C57BL/6 mice were sacrificed post-infection to assess bacterial loads, inflammation, and pathology.

Results

Nucleosome and neutrophil elastase levels were markedly elevated in patients compared to controls. NETs killed B. pseudomallei effectively, and neutrophils stimulated with B. pseudomallei showed increased elastase and DNA release in a time- and dose-dependent matter. In mice, NET disruption with intravenous DNase administration resulted in decreased nucleosome levels. Although DNase treatment of mice resulted in diminished liver inflammation, no differences were observed in bacterial dissemination or systemic inflammation.

Conclusion

B. pseudomallei is a potent inducer of NETosis which was reflected by greatly increased levels of NET-related components in melioidosis patients. Although NETs exhibited antibacterial activity against B. pseudomallei, NET formation did not protect against bacterial dissemination and inflammation during B. pseudomallei-induced sepsis.

Electronic supplementary material

The online version of this article (doi:10.1186/s40635-014-0021-2) contains supplementary material, which is available to authorized users.

Reprint of: A rapid increase in macrophage-derived versican and hyaluronan in infectious lung disease

The goals of this study were to characterize the changes in chondroitin sulfate proteoglycans and hyaluronan in lungs in acute response to gram-negative bacterial infection and to identify cellular components responsible for these changes. Mice were treated with intratracheal (IT) live Escherichia coli, E. coli lipopolysaccharide (LPS), or PBS. Both E. coli and LPS caused rapid selective increases in mRNA expression of versican and hyaluronan synthase (Has) isoforms 1 and 2 associated with increased immunohistochemical and histochemical staining for versican and hyaluronan in the lungs. Versican was associated with a subset of alveolar macrophages. To examine whether macrophages contribute to versican and hyaluronan accumulation, in vitro studies with primary cultures of bone marrow-derived and alveolar macrophages were performed. Unstimulated macrophages expressed very low levels of versican and hyaluronan synthase mRNA, with no detectible versican protein or hyaluronan product. Stimulation with LPS caused rapid increases in versican mRNA and protein, a rapid increase in Has1 mRNA, and concomitant inhibition of hyaluronidases 1 and 2, the major hyaluronan degrading enzymes. Hyaluronan could be detected following chloroquine pre-treatment, indicating rapid turnover and degradation of hyaluronan by macrophages. In addition, the effects of LPS, the M1 macrophage classical activation agonist, were compared to those of IL-4/IL-13 or IL-10, the M2a and M2c alternative activation agonists, respectively. Versican and Has1 increased only in response to M1 activation. Finally, the up-regulation of versican and Has1 in the whole lungs of wild-type mice following IT LPS was completely abrogated in TLR-4(-/-) mice. These findings suggest that versican and hyaluronan synthesis may play an important role in the innate immune response to gram-negative lung infection.

Fungi in the cystic fibrosis lung: bystanders or pathogens?

Improvement to the life expectancy of people with cystic fibrosis (PWCF) brings about novel challenges including the need for evaluation of the role of fungi in the cystic fibrosis (CF) lung. To determine if such organisms represent bystanders or pathogens affecting clinical outcomes we review the existing knowledge from a clinical, biochemical, inflammatory and immunological perspective. The prevalence and importance of fungi in the CF airway has likely been underestimated with the most frequently isolated filamentous fungi being Aspergillus fumigatus and Scedosporium apiospermum and the major yeast Candida albicans. Developing non-culture based microbiological methods for fungal detection has improved both our classification and understanding of their clinical consequences including localized, allergic and systemic infections. Cross-kingdom interaction between bacteria and fungi are discussed as is the role of biofilms further affecting clinical outcome. A combination of host and pathogen-derived factors determines if a particular fungus represents a commensal, colonizer or pathogen in the setting of CF. The underlying immune state, disease severity and treatment burden represent key host variables whilst fungal type, form, chronicity and virulence including the ability to evade immune recognition determines the pathogenic potential of a specific fungus at a particular point in time. Further research in this emerging field is warranted to fully elucidate the spectrum of disease conferred by the presence of fungi in the CF airway and the indications for therapeutic interventions.

Multiplexed measurements of immunomodulator levels in peripheral blood of healthy subjects: Effects of analytical variables based on anticoagulants, age, and gender

Multiplex microbead immunoassay (MMIA) is a powerful technology for a wide range of biomedical and clinical applications. It is important to study the normal concentration ranges of immunomodulators under different sample preparation conditions and age groups of subjects in order to more precisely determine their reference values for use in assessing alterations of their levels in disease. The aim of this study was to determine the plasma concentrations of immunomodulators (cytokines, chemokines, and growth factors) in the peripheral blood from healthy subjects by the use of a large multiplex panel, and to determine the effects of different anticoagulants, age, and gender on the immunomodulator levels. In addition, the assay precision for these biomarker analytes was determined. Plasma samples from 107 healthy subjects, aged 18 to 85 years, were collected in three different anticoagulants (sodium citrate, EDTA, Heparin); corresponding serum samples were also obtained. Multiplex microbead immunoassays were performed for measuring a total of 23 analytes including chemokines, cytokines, and growth factors (IL-1β, IL-1ra, IL-2, IL-6, IL-7, IL-8, IL-12 p70, IL-17, IFN-γ, IP-10, MCP-1, PDGF-BB, RANTES, TNF-α, IL-1a, IL-16, HGF, MIG, TNF-β, PDGF-ABBB, EGF, Flt-3 Ligand, VEGF). For these analytes, our results showed that the anticoagulant affected the concentration measurements and the coefficients of variation. However, the relative levels of the analytes (profiles) of samples collected in a particular anticoagulant are consistent. The analytes IL-1β, IL-7, Flt-3 Ligand, and IL-12p70 show the largest variation (up to fourfold) between the age groups. In addition, no statistically significant differences in the level of the analytes were found between the sexes.

A rapid increase in macrophage-derived versican and hyaluronan in infectious lung disease

The goals of this study were to characterize the changes in chondroitin sulfate proteoglycans and hyaluronan in lungs in acute response to gram-negative bacterial infection and to identify cellular components responsible for these changes. Mice were treated with intratracheal (IT) live Escherichia coli, E. coli lipopolysaccharide (LPS), or PBS. Both E. coli and LPS caused rapid selective increases in mRNA expression of versican and hyaluronan synthase (Has) isoforms 1 and 2 associated with increased immunohistochemical and histochemical staining for versican and hyaluronan in the lungs. Versican was associated with a subset of alveolar macrophages. To examine whether macrophages contribute to versican and hyaluronan accumulation, in vitro studies with primary cultures of bone marrow-derived and alveolar macrophages were performed. Unstimulated macrophages expressed very low levels of versican and hyaluronan synthase mRNA, with no detectible versican protein or hyaluronan product. Stimulation with LPS caused rapid increases in versican mRNA and protein, a rapid increase in Has1 mRNA, and concomitant inhibition of hyaluronidases 1 and 2, the major hyaluronan degrading enzymes. Hyaluronan could be detected following chloroquine pre-treatment, indicating rapid turnover and degradation of hyaluronan by macrophages. In addition, the effects of LPS, the M1 macrophage classical activation agonist, were compared to those of IL-4/IL-13 or IL-10, the M2a and M2c alternative activation agonists, respectively. Versican and Has1 increased only in response to M1 activation. Finally, the up-regulation of versican and Has1 in the whole lungs of wild-type mice following IT LPS was completely abrogated in TLR-4(-/-) mice. These findings suggest that versican and hyaluronan synthesis may play an important role in the innate immune response to gram-negative lung infection.

The fetal inflammatory response syndrome is a risk factor for morbidity in preterm neonates

OBJECTIVE

The aim of this study was to show and discuss an association between fetal inflammatory response syndrome (FIRS) and an adverse neonatal outcome defined as combined severe neonatal morbidity and mortality in preterm neonates hospitalized in our neonatal intensive care unit.

STUDY DESIGN

This was an observational study including all preterm neonates hospitalized in our neonatal intensive care unit over a 21 month period. FIRS was defined as cord blood interleukin (IL)-6 greater than 11 pg/mL. Main outcome parameter was an adverse neonatal outcome defined as hospital mortality and/or the presence of any of 5 prespecified morbidities (bronchopulmonary dysplasia, periventricular leukomalacia, intraventricular hemorrhage, and early- or late-onset sepsis).

RESULTS

Fifty-seven of 176 preterm infants hospitalized during the study period (32%) had an adverse neonatal outcome and 62 of these 176 infants (35%) had FIRS with median IL-6 values of 51.8 pg/mL (range, 11.2 to >1000 pg/mL). In a regression analysis, FIRS was significantly associated with adverse neonatal outcome (P < .001) and with the single outcome parameters, intraventricular hemorrhage and early-onset sepsis (P = .006 and P = .018, respectively). In the bivariate analysis, FIRS was associated with death and bronchopulmonary dysplasia (P = .004 and P < .001, respectively). IL-6 correlated with adverse neonatal outcome (r = 0.411, P < .001). When comparing the correlation in neonates less than 32 weeks' gestational age (r = 0.481, P < .001) with neonates 32 weeks or longer (r = 0.233, P = .019), the difference was nearly significant (P = .065).

CONCLUSION

FIRS is a risk factor for adverse neonatal outcome in preterm infants. In particular, the combination of IL-6 greater than 11 pg/mL and low gestational age increased the risk for severe neonatal morbidity or death.

Perilla frutescens leaf extract inhibits mite major allergen Der p 2-induced gene expression of pro-allergic and pro-inflammatory cytokines in human bronchial epithelial cell BEAS-2B

Perilla frutescens has been used in traditional medicine for respiratory diseases due to its anti-bacterial and anti-inflammatory activity. This study aimed to investigate effects of Perilla frutescens leaf extract (PFE) on expression of pro-allergic and pro-inflammatory cytokines in airway epithelial cells exposed to mite major allergen Der p 2 (DP2) and the underlying mechanisms. Our results showed that PFE up to 100 µg/mL had no cytotoxic effect on human bronchial epithelial cell BEAS-2B. Further investigations revealed that PFE dose-dependently diminished mRNA expression of pro-allergic cytokine IL-4, IL-5, IL-13 and GM-CSF, as well as pro-inflammatory cytokine IL-6, IL-8 and MCP-1 in BEAS-2B cells treated with DP2. In parallel to mRNA, the DP-2-elevated levels of the tested cytokines were decreased. Further investigation showed that DP2-indued phosphorylation of p38 MAPK (P38) and JNK, but not Erk1/2, was also suppressed by PFE. In addition, PFE elevated cytosolic IκBα level and decreased nuclear NF-κB level in DP2-stimulated BEAS-2B cells. Taken together, these findings revealed that PFE significantly diminished both mRNA expression and protein levels of pro-allergic and pro-inflammatory cytokines in response to DP2 through inhibition of P38/JNK and NK-κB activation. These findings suggest that PFE should be beneficial to alleviate both allergic and inflammatory responses on airway epithelium in response to aeroallergens.

Protective efficacy of orally administered, heat-killed Lactobacillus pentosus b240 against influenza A virus

Influenza A(H1N1)pdm virus caused the first human pandemic of the 21st century. Although various probiotic Lactobacillus species have been shown to have anti-microbial effects against pneumonia-inducing pathogens, the prophylactic efficacy and mechanisms behind their protection remain largely unknown. Here, we evaluated the prophylactic efficacy of heat-killed Lactobacillus pentosus b240 against lethal influenza A(H1N1)pdm virus infection in a mouse model. To further define the protective responses induced by b240, we performed virologic, histopathologic, and transcriptomic analyses on the mouse lungs. Although we did not observe an appreciable effect of b240 on virus growth, cytokine production, or histopathology, gene expressional analysis revealed that oral administration of b240 differentially regulates antiviral gene expression in mouse lungs. Our results unveil the possible mechanisms behind the protection mediated by b240 against influenza virus infection and provide new insights into probiotic therapy.

The effect of air pollutants on the microecology of the respiratory tract of rats

To study the effect of air pollution on the microecology of the respiratory tracts and the relationship of the biotopes with respiratory diseases, Wistar rats exposed to mixed air pollutants were used as poisoning models. The bacterial floras of respiratory tract were analyzed as well as expression of pro-inflammatory mediators of the respiratory epithelium. The mRNA and protein expression levels of pro-inflammatory factor and cytokines measured showed that there were significant changes in the microbiocenosis of the respiratory tract. The microorganisms underwent quantitative and qualitative changes following exposure to mixed air pollutants including a decline of indigenous microflora and increase of the content of conditionally pathogenic microorganisms. These changes depended on the degree of air pollution severity. Measurement of pro-inflammatory factors CC16, TNF-α and IL-6 revealed a similar time-dependent relationship between the content of conditionally pathogenic microorganisms and the interference of CC16 secretion, as well as up-expression of TNF-α and IL-6.

Anti-inflammatory activity of N-(3-florophenyl)ethylcaffeamide in mice

In this study, we evaluated the anti-inflammatory activity of one synthetic product, N-(3-Florophenyl)ethylcaffeamide (abbrev. FECA), by using animal model of λ-carrageenan-induced paw edema in mice. The anti-inflammatory mechanism of FECA was determined by measuring the levels of cyclooxygenase-2 (COX-2), nitric oxide (NO), tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), and malondialdehyde (MDA) in the edema paw tissue, and the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GRd) in the liver. The results showed that FECA reduced the paw edema at three, four and five hours after λ-carrageenan administration. The levels of COX-2, NO, TNF-α, and MDA in the λ-carrageenan-induced edema paws were reduced and the activities of SOD, GPx, and GRd in liver tissues were raised by FECA. These results suggested that FECA possessed anti-inflammatory activities and the anti-inflammatory mechanisms might be related to the decrease of the levels of COX-2, NO, and TNF-α in inflamed tissues and the increase in the MDA level by increasing the activities of SOD, GPx, and GRd.

Myeloid depletion of SOCS3 enhances LPS-induced acute lung injury through CCAAT/enhancer binding protein δ pathway

Although uncontrolled inflammatory response plays a central role in the pathogenesis of acute lung injury (ALI), the precise molecular mechanisms underlying the development of this disorder remain poorly understood. SOCS3 is an important negative regulator of IL-6-type cytokine signaling. SOCS3 is induced in lung during LPS-induced lung injury, suggesting that generation of SOCS3 may represent a regulatory product during ALI. In the current study, we created mice lacking SOCS3 expression in macrophages and neutrophils (LysM-cre SOCS3(fl/fl)). We evaluated the lung inflammatory response to LPS in both LysM-cre SOCS3(fl/fl) mice and the wild-type (WT) mice (SOCS3(fl/fl)). LysM-cre SOCS3(fl/fl) mice displayed significant increase of the lung permeability index (lung vascular leak of albumin), neutrophils, lung neutrophil accumulation (myeloperoxidase activity), and proinflammatory cytokines/chemokines in bronchial alveolar lavage fluids compared to WT mice. These phenotypes were consistent with morphological evaluation of lung, which showed enhanced inflammatory cell influx and intra-alveolar hemorrhage. We further identify the transcription factor, CCAAT/enhancer-binding protein (C/EBP) δ as a critical downstream target of SOCS3 in LPS-induced ALI. These results indicate that SOCS3 has a protective role in LPS-induced ALI by suppressing C/EBPδ activity in the lung. Elucidating the function of SOCS3 would represent prospective targets for a new generation of drugs needed to treat ALI.

Arctigenin ameliorates inflammation in vitro and in vivo by inhibiting the PI3K/AKT pathway and polarizing M1 macrophages to M2-like macrophages

Seeds of Arctium lappa, containing arctigenin and its glycoside arctiin as main constituents, have been used as a diuretic, anti-inflammatory and detoxifying agent in Chinese traditional medicine. In our preliminary study, arctigenin inhibited IKKβ and NF-κB activation in peptidoglycan (PGN)- or lipopolysaccharide (LPS)-induced peritoneal macrophages. To understand the anti-inflammatory effect of arctigenin, we investigated its anti-inflammatory effect in LPS-stimulated peritoneal macrophages and on LPS-induced systemic inflammation as well as 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice. Arctigenin inhibited LPS-increased IL-1β, IL-6 and TNF-α expression in LPS-stimulated peritoneal macrophages, but increased LPS-reduced IL-10 and CD204 expression. Arctigenin inhibited LPS-induced PI3K, AKT and IKKβ phosphorylation, but did not suppress LPS-induced IRAK-1 phosphorylation. However, arctigenin did not inhibit NF-κB activation in LPS-stimulated PI3K siRNA-treated peritoneal macrophages. Arctigenin suppressed the binding of p-PI3K antibody and the nucleus translocation of NF-κB p65 in LPS-stimulated peritoneal macrophages. Arctigenin suppressed blood IL-1β and TNF-α level in mice systemically inflamed by intraperitoneal injection of LPS. Arctigenin also inhibited colon shortening, macroscopic scores and myeloperoxidase activity in TNBS-induced colitic mice. Arctigenin inhibited TNBS-induced IL-1β, TNF-α and IL-6 expression, as well as PI3K, AKT and IKKβ phosphorylation and NF-κB activation in mice, but increased IL-10 and CD204 expression. However, it did not affect IRAK-1 phosphorylation. Based on these findings, arctigenin may ameliorate inflammatory diseases, such as colitis, by inhibiting PI3K and polarizing M1 macrophages to M2-like macrophages.

CCAAT-enhancer binding protein delta (C/EBPδ) protects against Klebsiella pneumoniae-induced pulmonary infection: potential role for macrophage migration

Mounting evidence suggests an important role for CCAAT-enhancer binding protein delta (C/EBPδ) in the acute-phase response after bacterial infection. However, whether C/EBPδ limits pneumonia remains elusive and is the aim of this study. Therefore, bacterial outgrowth, inflammatory responses, inflammatory cell influx, and survival were assessed in wild-type and C/EBPδ(-/-) mice infected with Klebsiella pneumoniae via the airways. We showed that C/EBPδ expression is highly induced in the lung during pulmonary infection and that Klebsiella-induced mortality was significantly increased among C/EBPδ(-/-) mice. Bacterial loads and inflammatory responses were similar in wild-type and C/EBPδ(-/-) mice early during infection, whereas bacterial loads were increased in C/EBPδ(-/-) mice later during infection. Moreover, macrophage numbers were reduced in lungs of C/EBPδ(-/-) mice. In vitro experiments showed that C/EBPδ only slightly affects macrophage function. Our data thus show that C/EBPδ contributes to host defense against Klebsiella-induced pneumonia and suggests that C/EBPδ-dependent macrophage mobilization is a key mechanism.