Critical role of CCL4 in eosinophil recruitment into the airway

Single-cell transcriptomics reveal the microenvironment landscape of perfluorooctane sulfonate-induced liver injury in female mice

Epidemic and animal studies have reported that perfluoroalkyl and polyfluoroalkyl substances (PFASs) are strongly associated with liver injury; however, to date, the effects of PFASs on the hepatic microenvironment remain largely unknown. In this study, we established perfluorooctane sulfonic acid (PFOS)-induced liver injury models by providing male and female C57BL/6 mice with water containing PFOS at varying doses for 4 weeks. Hematoxylin and eosin staining revealed that PFOS induced liver injury in both sexes. Elevated levels of serum aminotransferases including those of alanine aminotransferase and aspartate transaminase were detected in the serum of mice treated with PFOS. Female mice exhibited more severe liver injury than male mice. We collected the livers from female mice and performed single-cell RNA sequencing. In total, 36,529 cells were included and grouped into 10 major cell types: B cells, granulocytes, T cells, NK cells, monocytes, dendritic cells, macrophages, endothelial cells, fibroblasts, and hepatocytes. Osteoclast differentiation was upregulated and the T cell receptor signaling pathway was significantly downregulated in PFOS-treated livers. Further analyses revealed that among immune cell clusters in PFOS-treated livers, Tcf7+CD4+T cells were predominantly downregulated, whereas conventional dendritic cells and macrophages were upregulated. Among the fibroblast subpopulations, hepatic stellate cells were significantly enriched in PFOS-treated female mice. CellphoneDB analysis suggested that fibroblasts interact closely with endothelial cells. The major ligand-receptor pairs between fibroblasts and endothelial cells in PFOS-treated livers were Dpp4_Cxcl12, Ackr3_Cxcl12, and Flt1_complex_Vegfa. These genes are associated with directing cell migration and angiogenesis. Our study provides a general framework for understanding the microenvironment in the livers of female mice exposed to PFOS at the single-cell level.

Multi-omic integration reveals alterations in nasal mucosal biology that mediate air pollutant effects on allergic rhinitis

BACKGROUND

Allergic rhinitis is a common inflammatory condition of the nasal mucosa that imposes a considerable health burden. Air pollution has been observed to increase the risk of developing allergic rhinitis. We addressed the hypotheses that early life exposure to air toxics is associated with developing allergic rhinitis, and that these effects are mediated by DNA methylation and gene expression in the nasal mucosa.

METHODS

In a case-control cohort of 505 participants, we geocoded participants' early life exposure to air toxics using data from the US Environmental Protection Agency, assessed physician diagnosis of allergic rhinitis by questionnaire, and collected nasal brushings for whole-genome DNA methylation and transcriptome profiling. We then performed a series of analyses including differential expression, Mendelian randomization, and causal mediation analyses to characterize relationships between early life air toxics, nasal DNA methylation, nasal gene expression, and allergic rhinitis.

RESULTS

Among the 505 participants, 275 had allergic rhinitis. The mean age of the participants was 16.4 years (standard deviation = 9.5 years). Early life exposure to air toxics such as acrylic acid, phosphine, antimony compounds, and benzyl chloride was associated with developing allergic rhinitis. These air toxics exerted their effects by altering the nasal DNA methylation and nasal gene expression levels of genes involved in respiratory ciliary function, mast cell activation, pro-inflammatory TGF-β1 signaling, and the regulation of myeloid immune cell function.

CONCLUSIONS

Our results expand the range of air pollutants implicated in allergic rhinitis and shed light on their underlying biological mechanisms in nasal mucosa.

Relationship between serum IgA levels and low percentage forced expiratory volume in the first second in asthma

Objective: Immunoglobulin A (IgA) is suggested to have pathogenic effects in respiratory inflammatory diseases, including asthma. We aimed to analyze the relationship between serum IgA, and clinical indicators and biomarkers of asthma.Methods: This study was a post hoc analysis of the NHOM Asthma Study. In this study, serum IgA was measured using serum samples stored. We determined an association between the serum IgA level and clinical variables and biomarkers using multivariate linear regression and analyzed the differences in clinical indices between IgA high- and IgA low-asthma.Results: In this study, 572 patients with asthma were included in the final analysis. Lower percentage forced expiratory volume in the first second (%FEV1), higher serum eotaxin levels, lower serum ST2 levels, and higher serum MIP-1β levels, were independently and significantly associated with higher serum IgA levels among asthma patients by multivariate linear regression analysis (%FEV1, 95% confidence interval [CI], -8.18- -0.613, p < 0.05; eotaxin, 95% CI, 8.95-46.69, p < 0.001; ST2, 95% CI, -73.71- -7.37, p < 0.05; and MIP-1β, 95% CI, 1.47-18.71, p < 0.05). Furthermore, IgA high-asthma (serum IgA ≥ 238 mg/dL, n = 270) and IgA low-asthma (serum IgA < 238 mg/dL, n = 302) were compared separately. %FEV1 was significantly lower, the percentage of atopy was higher, and serum MIP-1β level was higher in IgA high-asthma.Conclusions: This study suggests that serum IgA may be involved in the worsening of asthma outcomes, as assessed by %FEV1 and enhanced inflammation via elevated serum MIP-1β.

Human bocavirus 1 coinfection is associated with decreased cytokine expression in the rhinovirus-induced first wheezing episode in children

BACKGROUND

Rhinovirus (RV)-induced first wheezing episodes in children are associated with a markedly increased risk of asthma. Previous studies have suggested that human bocavirus 1 (HBoV1) may modify RV-induced immune responses in young children. We investigated cytokine profiles of sole RV- and dual RV-HBoV1-induced first wheezing episodes, and their association with severity and prognosis.

METHODS

Fifty-two children infected with only RV and nine children infected with dual RV-HBoV1, aged 3-23 months, with severe first wheezing episodes were recruited. At acute illness and 2 weeks later, peripheral blood mononuclear cells were isolated, and stimulated with anti-CD3/anti-CD28 in vitro. Multiplex ELISA was used to quantitatively identify 56 different cytokines at both study points. Patients were prospectively followed for 4 years.

RESULTS

The mean age of the children was 14.3 months, and 30% were sensitized. During the acute illness, the adjusted analyses revealed a decrease in the expression of IL-1b, MIP-1b, Regulated upon activation, normal T cell expressed and presumably secreted (CCL5), TNF-a, TARC, and ENA-78 in the RV-HBoV1 group compared with the RV group. In the convalescence phase, the RV-HBoV1 group was characterized by decreased expression of Fractalkine, MCP-3, and IL-8 compared to the RV group. Furthermore, the hospitalization time was associated with the virus group and cytokine response (interaction p < 0.05), signifying that increased levels of epidermal growth factor and MIP-1b were related with a shorter duration of hospitalization in the RV-HBoV1 coinfection group but not in the RV group.

CONCLUSIONS

Different cytokine response profiles were detected between the RV and the RV-HBoV1 groups. Our results show the idea that RV-induced immune responses may be suppressed by HBoV1.

Characterization of Lung Inflammatory Response to Aspergillus fumigatus Spores

The airway exposure to Aspergillus fumigatus spores (AFsp) is associated with an inflammatory response, potentially leading to allergic and/or chronic pulmonary aspergillosis. The aim of our study is to better understand the host response, first in vitro, then in vivo, following the chronic exposure of mice to AFsp. We investigated the inflammatory response to AFsp in cell mono- and co-culture systems with murine macrophages and alveolar epithelial cells. The mice were subjected to two intranasal instillations using 10⁵ AFsp. Their lungs were processed for inflammatory and histopathological analyses. In cell culture, the gene expressions significantly increased for TNF-α, CXCL-1, CXCL-2, IL-1β, IL-1α and GM-CSF in macrophages, with these increases being limited for TNF-α, CXCL-1 and IL-1α in epithelial cells. In co-culture, increases in the TNF-α, CXCL-2 and CXCL-1 gene expressions were observed to be associated with increased protein levels. The in vivo lung histological analyses of mice challenged by AFsp showed cellular infiltrates in the peribronchial and/or alveolar spaces. A Bio-Plex approach on the bronchoalveolar lavage revealed significant increases in the protein secretion of selected mediators of the challenged mice compared to the unchallenged mice. In conclusion, the exposure to AFsp resulted in a marked inflammatory response of macrophages and epithelial cells. These inflammatory findings were confirmed in mouse models associated with lung histologic changes.

Characterization of Chemotaxis-Associated Gene Dysregulation in Myeloid Cell Populations in the Lungs during Lipopolysaccharide-Mediated Acute Lung Injury

During endotoxin-induced acute lung injury (ALI), immune cell recruitment resulting from chemotaxis is mediated by CXC and CC chemokines and their receptors. In this study, we investigated the role of chemokines and their receptors in the regulation of myeloid cell populations in the circulation and the lungs of C57BL/6J mice exhibiting LPS-mediated ALI using single-cell RNA sequencing. During ALI, there was an increase in the myeloid cells, M1 macrophages, monocytes, neutrophils, and other granulocytes, whereas there was a decrease in the residential alveolar macrophages and M2 macrophages. Interestingly, LPS triggered the upregulation of CCL3, CCL4, CXCL2/3, and CXCL10 genes associated with cellular migration of various subsets of macrophages, neutrophils, and granulocytes. Furthermore, there was an increase in the frequency of myeloid cells expressing CCR1, CCR3, CCR5, and CXCR2 receptors during ALI. MicroRNA sequencing studies of vehicle versus LPS groups identified several dysregulated microRNAs targeting the upregulated chemokine genes. This study suggests that chemokine ligand-receptors interactions are responsible for myeloid cell heterogenicity and cellular recruitment to the lungs during ALI. The single-cell transcriptomics allowed for an in-depth assessment and characterization of myeloid cells involved in immune cell trafficking during ALI.

IFN- Is Protective in Cytokine Release Syndrome-associated Extrapulmonary Acute Lung Injury

The mechanisms by which excessive systemic activation of adaptive T lymphocytes, as in cytokine release syndrome (CRS), leads to innate immune cell-mediated acute lung injury (ALI) or acute respiratory distress syndrome, often in the absence of any infection, remains unknown. Here, we investigated the roles of IFN-γ and IL-17A, key T-cell cytokines significantly elevated in patients with CRS, in the immunopathogenesis of CRS-induced extrapulmonary ALI. CRS was induced in wild-type (WT), IL-17A- and IFN-γ knockout (KO) human leukocyte antigen-DR3 transgenic mice with 10 μg of the superantigen, staphylococcal enterotoxin B, given intraperitoneally. Several ALI parameters, including gene expression profiling in the lungs, were studied 4, 24, or 48 hours later. Systemic T-cell activation with staphylococcal enterotoxin B resulted in robust upregulation of several chemokines, S100A8/A9, matrix metalloproteases, and other molecules implicated in tissue damage, granulocyte as well as agranulocyte adhesion, and diapedesis in the lungs as early as 4 hours, which was accompanied by subsequent neutrophil/eosinophil lung infiltration and severe ALI in IFN-γ KO mice. These pathways were significantly underexpressed in IL-17A KO mice, which manifested mildest ALI and intermediate in WT mice. Neutralization of IFN-γ worsened ALI in WT and IL-17A KO mice, whereas neutralizing IL-17A did not mitigate lung injury in IFN-γ KO mice, suggesting a dominant protective role for IFN-γ in ALI and that IL-17A is dispensable. Ruxolitinib, a Janus kinase inhibitor, increased ALI severity in WT mice. Thus, our study identified novel mechanisms of ALI in CRS and its differential modulation by IFN-γ and IL-17A.

CCL4 Regulates Eosinophil Activation in Eosinophilic Airway Inflammation

Eosinophilic chronic rhinosinusitis (ECRS) is a refractory airway disease accompanied by eosinophilic inflammation, the mechanisms of which are unknown. We recently found that CCL4/MIP-1β-a specific ligand for CCR5 receptors-was implicated in eosinophil recruitment into the inflammatory site and was substantially released from activated eosinophils. Moreover, it was found in nasal polyps from patients with ECRS, primarily in epithelial cells. In the present study, the role of epithelial cell-derived CCL4 in eosinophil activation was investigated. First, CCL4 expression in nasal polyps from patients with ECRS as well as its role of CCL4 in eosinophilic airway inflammation were investigated in an in vivo model. Furthermore, the role of CCL4 in CD69 expression-a marker of activated eosinophils-as well as the signaling pathways involved in CCL4-mediated eosinophil activation were investigated. Notably, CCL4 expression, but not CCL5, CCL11, or CCL26, was found to be significantly increased in nasal polyps from patients with ECRS associated with eosinophil infiltration as well as in BEAS-2B cells co-incubated with eosinophils. In an OVA-induced allergic mouse model, CCL4 increased eosinophil accumulation in the nasal mucosa and the bronchoalveolar lavage (BALF). Moreover, we found that CD69 expression was upregulated in CCL4-stimulated eosinophils; similarly, phosphorylation of several kinases, including platelet-derived growth factor receptor (PDGFR)β, SRC kinase family (Lck, Src, and Yes), and extracellular signal-regulated kinase (ERK), was upregulated. Further, CCR5, PDGFRβ, and/or Src kinase inhibition partially restored CCL4-induced CD69 upregulation. Thus, CCL4, which is derived from airway epithelial cells, plays a role in the accumulation and activation of eosinophils at inflammatory sites. These findings may provide a novel therapeutic target for eosinophilic airway inflammation, such as ECRS.

Effects of a natural nutritional supplement on immune cell infiltration and immune gene expression in exercise-induced injury

Inflammatory immune response plays a key role in exercise-induced injury and healing; however, the relevant regulatory mechanisms of immune infiltration in exercise-induced injuries remain less studied. In the present study, a highly efficient system for screening immunity-related biomarkers and immunomodulatory ability of natural nutritional supplements was developed by integrating intelligent data acquisition, data mining, network pharmacology, and computer-assisted target fishing. The findings demonstrated that resting natural killer cells showed a higher rate of infiltration after exercise, whereas naive B cells and activated dendritic cells showed higher rate of infiltration before exercise. Four key genes, namely PRF1, GZMB, CCL4, and FASLG, were associated with exercise-induced injuries and inflammatory immune response. In total, 26 natural compounds including echinacoside, eugenol, tocopherol, and casuariin were predicted by using the HERB databases. Molecular docking analysis showed that GZMB, FASLG, and CCL4 bound to echinacoside. In vivo experiments in mice showed that after 30 min swimming, natural killer (NK) cells showed high infiltration rates, and the key genes (GZMB, PRF1, FASLG, and CCL4) were highly expressed; however, echinocandin significantly reduced the level of NK cells and decreased the expression of the four key genes post exercise. This natural nutritional supplement may act to protect against inflammatory injury after exercise by suppressing specific immune infiltration.

Starch-based NP act as antigen delivery systems without immunomodulating effect

The nasal route of immunization has become a real alternative to injections. It is indeed described as more efficient at inducing immune protection, since it initiates both mucosal and systemic immunity, thus protecting against both the infection itself and the transmission of pathogens by the host. However, the use of immunomodulators should be limited since they induce inflammation. Here we investigated in vitro the mechanisms underlying the enhancement of antigen immunogenicity by starch nanoparticles (NPL) delivery systems in H292 epithelial cells, as well as the NPL’s immunomodulatory effect. We observed that NPL had no intrinsic immunomodulatory effect but enhanced the immunogenicity of an E. coli lysate (Ag) merely by increasing its intracellular delivery. Moreover, we demonstrated the importance of the NPL density on their efficiency by comparing reticulated (NPL) and non-reticulated particles (NPL·NR). These results show that an efficient delivery system is sufficient to induce a mucosal immune response without the use of immunomodulators.

CCL4 Functions as a Biomarker of Type 2 Airway Inflammation

Eosinophilic airway inflammatory disease is associated with bronchial asthma, with eosinophilic chronic rhinosinusitis (ECRS) typical of refractory type 2 airway inflammation. CCL4 produced at local inflammatory sites is involved in them via the accumulation and activation of type 2 inflammatory cells, including eosinophils. The detailed mechanism of CCL4 production remains unclear, and also the possibility it could function as a biomarker of type 2 airway inflammation remains unresolved. In this study, we evaluated CCL4 mRNA expression and production via the TSLP receptor (TSLPR) and toll-like receptors (TLRs) or proteinase-activated receptor-2 (PAR2) in BEAS-2B bronchial epithelial cells co-incubated with purified eosinophils or eosinophil peroxidase (EPX). We examined serum chemokine (CCL4, CCL11, CCL26, and CCL17) and total IgE serum levels, fractionated exhaled nitrogen oxide (FENO), and CCL4 expression in nasal polyps in patients with severe ECRS and asthma. CCL4 was induced by TSLP under eosinophilic inflammation. Furthermore, CCL4 was released via TLR3 signaling, which was enhanced by TSLP. CCL4 was mainly located in nasal polyp epithelial cells, while serum CCL4 levels were reduced after dupilumab treatment. Serum CCL4 levels were positively correlated with FENO, serum IgE, and CCL17 levels. Thus, CCL4 released from epithelial cells via the innate immune system during type 2 airway inflammation may function as a useful biomarker for the condition.

The role of human mast cells in allergy and asthma

Mast cells are tissue-inhabiting cells that play an important role in inflammatory diseases of the airway tract. Mast cells arise in the bone marrow as progenitor cells and complete their differentiation in tissues exposed to the external environment, such as the skin and respiratory tract, and are among the first to respond to bacterial and parasitic infections. Mast cells express a variety of receptors that enable them to respond to a wide range of stimulants, including the high-affinity FcεRI receptor. Upon initial contact with an antigen, mast cells are sensitized with IgE to recognize the allergen upon further contact. FcεRI-activated mast cells are known to release histamine and proteases that contribute to asthma symptoms. They release a variety of cytokines and lipid mediators that contribute to immune cell accumulation and tissue remodeling in asthma. Mast cell mediators trigger inflammation and also have a protective effect. This review aims to update the existing knowledge on the mediators released by human FcεRI-activated mast cells, and to unravel their pathological and protective roles in asthma and allergy. In addition, we highlight other diseases that arise from mast cell dysfunction, the therapeutic approaches used to address them, and fill the gaps in our current knowledge. Mast cell mediators not only trigger inflammation but may also have a protective effect. Given the differences between human and animal mast cells, this review focuses on the mediators released by human FcεRI-activated mast cells and the role they play in asthma and allergy.

Dual role for CXCR3 and CCR5 in asthmatic type 1 inflammation

BACKGROUND

Many patients with severe asthma (SA) fail to respond to type 2 inflammation-targeted therapies. We previously identified a cohort of subjects with SA expressing type 1 inflammation manifesting with IFN-γ expression and variable type 2 responses.

OBJECTIVE

We investigated the role of the chemotactic receptors C-X-C chemokine receptor 3 (CXCR3) and C-C chemokine receptor 5 (CCR5) in establishing type 1 inflammation in SA.

METHODS

Bronchoalveolar lavage microarray data from the Severe Asthma Research Program I/II were analyzed for pathway expression and paired with clinical parameters. Wild-type, Cxcr3-/-, and Ccr5-/- mice were exposed to a type 1-high SA model with analysis of whole lung gene expression and histology. Wild-type and Cxcr3-/- mice were treated with a US Food and Drug Administration-approved CCR5 inhibitor (maraviroc) with assessment of airway resistance, inflammatory cell recruitment by flow cytometry, whole lung gene expression, and histology.

RESULTS

A cohort of subjects with increased IFN-γ expression showed higher asthma severity. IFN-γ expression was correlated with CXCR3 and CCR5 expression, but in Cxcr3-/- and Ccr5-/- mice type 1 inflammation was preserved in a murine SA model, most likely owing to compensation by the other pathway. Incorporation of maraviroc into the experimental model blunted airway hyperreactivity despite only mild effects on lung inflammation.

CONCLUSIONS

IFNG expression in asthmatic airways was strongly correlated with expression of both the chemokine receptors CXCR3 and CCR5. Although these pathways provide redundancy for establishing type 1 lung inflammation, inhibition of the CCL5/CCR5 pathway with maraviroc provided unique benefits in reducing airway hyperreactivity. Targeting this pathway may be a novel approach for improving lung function in individuals with type 1-high asthma.

Gram-negative microbiota is related to acute exacerbation in children with asthma

BACKGROUND

The upper-airway microbiota may be associated with the pathogenesis of asthma and useful for predicting acute exacerbation. However, the relationship between the lower-airway microbiota and acute exacerbation in children with asthma is not well understood. We evaluated the characteristics of the airway microbiome using induced sputum from children with asthma exacerbation and compared the microbiota-related differences of inflammatory cytokines with those in children with asthma.

METHODS

We analysed the microbiome using induced sputum during acute exacerbation of asthma in children. We identified microbial candidates that were prominent in children with asthma exacerbation and compared them with those in children with stable asthma using various analytical methods. The microbial candidates were analysed to determine their association with inflammatory cytokines. We also developed a predictive functional profile using PICRUSt.

RESULTS

A total of 95 children with allergic sensitisation including 22 with asthma exacerbation, 67 with stable asthma, and 6 controls were evaluated. We selected 26 microbial candidates whose abundances were significantly increased, decreased, or correlated during acute exacerbation in children with asthma. Among the microbial candidates, Campylobacter, Capnocytophaga, Haemophilus, and Porphyromonas were associated with inflammatory cytokines including macrophage inflammatory protein (MIP)-1β, programmed death-ligand 1, and granzyme B. Both Campylobacter and MIP-1β levels were correlated with sputum eosinophils. Increased lipopolysaccharide biosynthesis and decreased glycan degradation were observed in children with asthma exacerbation.

CONCLUSION

Gram-negative microbes in the lower airway were related to acute exacerbation in children with asthma. These microbes and associated cytokines may play a role in exacerbating asthma in children.

Eosinophil-mediated inflammation in the absence of eosinophilia

The increase of eosinophil levels is a hallmark of type-2 inflammation. Blood eosinophil counts act as a convenient biomarker for asthma phenotyping and the selection of biologics, and they are even used as a prognostic factor for severe coronavirus disease 2019. However, the circulating eosinophil count does not always reflect tissue eosinophilia and vice versa. The mismatch of blood and tissue eosinophilia can be seen in various clinical settings. For example, blood eosinophil levels in patients with acute eosinophilic pneumonia are often within normal range despite the marked symptoms and increased number of eosinophils in bronchoalveolar lavage fluid. Histological studies using immunostaining for eosinophil granule proteins have revealed the extracellular deposition of granule proteins coincident with pathological conditions, even in the absence of a significant eosinophil infiltrate. The marked deposition of eosinophil granule proteins in tissue is often associated with cytolytic degranulation. Recent studies have indicated that extracellular trap cell death (ETosis) is a major mechanism of cytolysis. Cytolytic ETosis is a total cell degranulation in which cytoplasmic and nuclear contents, including DNA and histones that act as alarmins, are also released. In the present review, eosinophil-mediated inflammation in such mismatch conditions is discussed.

Omalizumab Restores Response to Corticosteroids in Patients with Eosinophilic Chronic Rhinosinusitis and Severe Asthma

Eosinophilic chronic rhinosinusitis (ECRS), which is a subgroup of chronic rhinosinusitis with nasal polyps, is characterized by eosinophilic airway inflammation extending across both the upper and lower airways. Some severe cases are refractory even after endoscopic sinus surgery, likely because of local steroid insensitivity. Although real-life studies indicate that treatment with omalizumab for severe allergic asthma improves the outcome of coexistent ECRS, the underlying mechanisms of omalizumab in eosinophilic airway inflammation have not been fully elucidated. Twenty-five patients with ECRS and severe asthma who were refractory to conventional treatments and who received omalizumab were evaluated. Nineteen of twenty-five patients were responsive to omalizumab according to physician-assessed global evaluation of treatment effectiveness. In the responders, the levels of peripheral blood eosinophils and fractionated exhaled nitric oxide (a marker of eosinophilic inflammation) and of CCL4 and soluble CD69 (markers of eosinophil activation) were reduced concomitantly with the restoration of corticosteroid sensitivity. Omalizumab restored the eosinophil-peroxidase-mediated PP2A inactivation and steroid insensitivity in BEAS-2B. In addition, the local inflammation simulant model using BEAS-2B cells incubated with diluted serum from each patient confirmed omalizumab’s effects on restoration of corticosteroid sensitivity via PP2A activation; thus, omalizumab could be a promising therapeutic option for refractory eosinophilic airway inflammation with corticosteroid resistance.

Basil Polysaccharide Reverses Development of Experimental Model of Sepsis-Induced Secondary Staphylococcus aureus Pneumonia

Background

Basil polysaccharide (BPS) represents a main active ingredient extracted from basil (Ocimum basilicum L.), which can regulate secondary bacterial pneumonia development in the process of sepsis-mediated immunosuppression.

Methods

In this study, a dual model of sepsis-induced secondary pneumonia with cecal ligation and puncture and intratracheal instillation of Staphylococcus aureus or Pseudomonas aeruginosa was constructed.

Results

The results indicated that BPS-treated mice undergoing CLP showed resistance to secondary S. aureus pneumonia. Compared with the IgG-treated group, BPS-treated mice exhibited better survival rate along with a higher bacterial clearance rate. Additionally, BPS treatment attenuated cell apoptosis, enhanced lymphocyte and macrophage recruitment to the lung, promoted pulmonary cytokine production, and significantly enhanced CC receptor ligand 4 (CCL4). Notably, recombinant CCL4 protein could enhance the protective effect on S. aureus-induced secondary pulmonary infection of septic mice, which indicated that BPS-induced CCL4 partially mediated resistance to secondary bacterial pneumonia. In addition, BPS priming markedly promoted the phagocytosis of alveolar macrophages while killing S. aureus in vitro, which was related to the enhanced p38MAPK signal transduction pathway activation. Moreover, BPS also played a protective role in sepsis-induced secondary S. aureus pneumonia by inducing Treg cell differentiation.

Conclusions

Collectively, these results shed novel lights on the BPS treatment mechanism in sepsis-induced secondary S. aureus pneumonia in mice.

Vinpocetine alleviates lung inflammation via macrophage inflammatory protein-1β inhibition in an ovalbumin-induced allergic asthma model

Asthma is a well-known bronchial disease that causes bronchial inflammation, narrowing of the bronchial tubes, and bronchial mucus secretion, leading to bronchial blockade. In this study, we investigated the association between phosphodiesterase (PDE), specifically PDE1, and asthma using 3-isobutyl-1-methylxanthine (IBMX; a non-specific PDE inhibitor) and vinpocetine (Vinp; a PDE1 inhibitor). Balb/c mice were randomized to five treatment groups: control, ovalbumin (OVA), OVA + IBMX, OVA + Vinp, and OVA + dexamethasone (Dex). All mice were sensitized and challenged with OVA, except for the control group. IBMX, Vinp, or Dex was intraperitoneally administered 1 h before the challenge. Vinp treatment significantly inhibited the increase in airway hyper-responsiveness (P<0.001) and reduced the number of inflammatory cells, particularly eosinophils, in the lungs (P<0.01). It also ameliorated the damage to the bronchi and alveoli and decreased the OVA-specific IgE levels in serum, an indicator of allergic inflammation increased by OVA (P<0.05). Furthermore, the increase in interleukin-13, a known Th2 cytokine, was significantly decreased by Vinp (P<0.05), and Vinp regulated the release and mRNA expression of macrophage inflammatory protein-1β (MIP-1β) increased by OVA (P<0.05). Taken together, these results suggest that PDE1 is associated with allergic lung inflammation induced by OVA. Thus, PDE1 inhibitors can be a promising therapeutic target for the treatment of asthma.

Comprehensive Analysis of ceRNA Regulation Network Involved in the Development of Coronary Artery Disease

Background

Coronary artery disease (CAD) is one of the most common causes of sudden death with high morbidity in recent years. This paper is aimed at exploring the early peripheral blood biomarkers of sudden death and providing a new perspective for clinical diagnosis and forensic pathology identification by integrated bioinformatics analysis.

Methods

Two microarray expression profiling datasets (GSE113079 and GSE31568) were downloaded from the Gene Expression Omnibus (GEO) database, and we identified differentially expressed lncRNAs, miRNAs, and mRNAs in CAD. Gene Ontology (GO) and KEGG pathway analyses of DEmRNAs were executed. A protein-protein interaction (PPI) network was constructed, and hub genes were identified. Finally, we constructed a competitive endogenous RNA (ceRNA) regulation network among lncRNAs, miRNAs, and mRNAs. Also, the 5 miRNAs of the ceRNA network were verified by RT-PCR.

Results

In total, 86 DElncRNAs, 148 DEmiRNAs, and 294 DEmRNAs were dysregulated in CAD. We received 12 GO terms and 5 pathways of DEmRNAs. 31 nodes and 78 edges were revealed in the PPI network. The top 10 genes calculated by degree method were identified as hub genes. Moreover, there were a total of 26 DElncRNAs, 5 DEmiRNAs, and 13 DEmRNAs in the ceRNA regulation network. We validated the 5 miRNAs of the ceRNA network by RT-PCR, which were consistent with the results of the microarray.

Conclusions

In this paper, a CAD-specific ceRNA network was successfully constructed, contributing to the understanding of the relationship among lncRNAs, miRNAs, and mRNAs. We identified potential peripheral blood biomarkers in CAD and provided novel insights into the development and progress of CAD.

Developments allergy in 2019 through the eyes of clinical and experimental allergy, part I mechanisms

In the first of two linked articles, we describe the development in the mechanisms underlying allergy as described by Clinical & Experimental Allergy and other journals in 2019. Experimental models of allergic disease, basic mechanisms, clinical mechanisms and allergens are all covered.

Respiratory exposure to PM2.5 soluble extract disrupts mucosal barrier function and promotes the development of experimental asthma

BACKGROUND

Air pollutants are important factors that contribute to the development and exacerbation of asthma, but experimental evidence still needs to be collected and the mechanisms still need to be addressed. In this study, we aimed to assess the association between PM2.5 exposure and asthma development. The effects of PM2.5 exposure on the barrier functions of airway epithelial cells were also determined.

METHODS

PM2.5 was collected from Nanjing, China, and its soluble extract was prepared. Human lung epithelial cells (BEAS-2B) were treated with different concentrations of soluble PM2.5 extract, and cell viability was detected by FACS using Annexin V-FITC staining. PM2.5-induced oxidative stress and inflammatory events were assessed by DCF-DA staining and qPCR. PM2.5-induced dysfunction of the airway epithelial barrier was assessed by measuring the expression of tight junction molecules. In vivo, BALB/c mice were treated with OVA in the presence or absence of PM2.5 solution, followed by exposure to OVA aerosols. Allergy-induced airway inflammation and lung injury were assessed by histopathological analyses.

RESULTS

Soluble PM2.5 extract exposure in vitro decreased the viability and increased apoptosis of airway epithelial cells. Soluble PM2.5 extract induced oxidative stress and enhanced pro-inflammatory factor expression by activating the NF-κB and MAPK signalling pathways, which were accompanied by reduced airway barrier function. The in vivo data demonstrated that PM2.5 exposure increased the effects of allergy sensitization after respiratory exposure to allergens, which led to the development of asthma.

CONCLUSION

This study suggests that exposure to soluble PM2.5 extract contributes to airway barrier dysfunction. The soluble mediators generated by airway epithelial cells in response to PM2.5 exposure orchestrate the breaking of inhalational tolerance and sensitization to allergic antigens, leading to the exacerbated development of asthma.

Possible Mechanisms of Eosinophil Accumulation in Eosinophilic Pneumonia

Eosinophilic pneumonia (EP), including acute EP and chronic EP, is characterized by the massive pulmonary infiltration of eosinophils into the lung. However, the mechanisms underlying the selective accumulation of eosinophils in EP have not yet been fully elucidated. We reported that bronchoalveolar lavage fluid (BALF) from EP patients induced the transmigration of eosinophils across endothelial cells in vitro. The concentrations of eotaxin-2 (CCL24) and monocyte chemotactic protein (MCP)-4 (CCL13), which are CC chemokine receptor (CCR) 3 ligands, were elevated in the BALF of EP patients, and anti-CCR3 monoclonal antibody inhibited the eosinophil transmigration induced by the BALF of EP patients. The concentration of macrophage inflammatory protein 1β (CCL4), a CCR5 ligand that induces eosinophil migration, was increased in the BALF of EP patients. Furthermore, the concentration of interleukin (IL) 5 was increased in the BALF of EP patients, and it has been reported that anti-IL-5 antibody treatment resulted in remission and the reduction of glucocorticoid use in some cases of chronic EP. The concentrations of lipid mediators, such as leukotriene (LT) B₄, damage-associated molecular pattern molecules (DAMPs), such as uric acid, or extracellular matrix proteins, such as periostin, were also increased in the BALF of EP patients. These findings suggest that chemokines, such as CCR3/CCR5 ligands, cytokines, such as IL-5, lipid mediators, such as LTB₄, DAMPs, and extracellular matrix proteins may play roles in the accumulation or activation of eosinophils in EP.

Cytokine profile in children with food allergy following liver transplantation

BACKGROUND

LTX in children is associated with increased risk of food allergy, and the mechanisms underlying this are unknown. We wanted to study whether plasma cytokine profile differed in liver transplanted children, with and without food allergy, and whether it differed from untransplanted children with CLD.

METHODS

Plasma cytokines, total and specific IgE in nine patients with food allergy were compared with 13 patients without food allergy following LTX, and also with seven untransplanted patients with CLD.

RESULTS

No difference was found in the cytokine profile between liver transplanted patients with and without food allergy. Transplanted patients with food allergy having received a prescription of epinephrine had a significantly higher total IgE (2033 [234-2831] vs 10 [5-41] IU/L, P = .002) and MIP-1b (52 [37-96] vs 36 [32-39], P = .035) compared with transplanted patients without food allergy. Two patients with severe food allergy responded favorably to conversion from tacrolimus-based immunosuppression to MMF and corticosteroids with reduction in clinical symptoms, total IgE, specific IgE, IL-1ra, IL-4, RANTES, PDGF, MIP-1a, and TNFα. The transplantation group had higher levels of IL-1b, IL-5, IL-7, IL-13, GCSF, IFNγ, and MIP-1a compared with the CLD group.

CONCLUSIONS

No overall difference was found in plasma cytokine profile between patients with and without food allergy. Patients with severe food allergy had significant elevation of MIP-1b. Discontinuation of tacrolimus reduced total and specific IgE and changed plasma cytokine profile. The plasma cytokine profile in liver transplanted children was different compared with children with CLD.

Reduced Local Response to Corticosteroids in Eosinophilic Chronic Rhinosinusitis with Asthma

Eosinophilic chronic rhinosinusitis (ECRS), a subgroup of chronic rhinosinusitis with nasal polyps, is recognized as a refractory eosinophilic disorder characterized by both upper and lower airway inflammation. In some severe cases, disease control is poor, likely due to local steroid insensitivity. In this study, we focused on protein phosphatase 2A (PP2A), a key factor regulating glucocorticoid receptor (GR) nuclear translocation, and examined its association with local responses to corticosteroids in eosinophilic airway inflammation. Our results indicated reduced responses to corticosteroids in nasal epithelial cells from ECRS patients with asthma, which were also associated with decreased PP2A mRNA expression. Eosinophil peroxidase stimulates elevated PP2A phosphorylation levels, reducing PP2A protein expression and activity. In addition, mRNA levels of inflammatory mediators (TSLP, IL-25, IL-33, CCL4, CCL5, CCL11, and CCL26) associated with eosinophilic airway inflammation in epithelial cells were increased in nasal polyps (eosinophil-rich areas) compared with those in uncinate process tissues (eosinophil-poor areas) from the same patients. PP2A reduction by siRNA reduced GR nuclear translocation, whereas PP2A overexpression by plasmid transfection, or PP2A activation by formoterol, enhanced GR nuclear translocation. Collectively, our findings indicate that PP2A may represent a promising therapeutic target in refractory eosinophilic airway inflammation characterized by local steroid insensitivity.

Eosinophilic Cholecystitis Occurred in a Patient With Refractory Eosinophilic Airway Inflammation: A Case Report

Background

Eosinophilic cholecystitis (EC) is a rare condition that presents in a manner comparable to acute cholecystitis. The diagnosis is based on classical symptoms of cholecystitis with excessive eosinophilic infiltration within the gallbladder. EC has been reported alone or in combination with manifestations, such as eosinophilic gastrointestinal tract inflammation. However, association with airway inflammation in patients with EC is rare.Case Presentation: We report the case of a 65-year-old man who had refractory eosinophilic chronic rhinosinusitis with bronchial asthma. A second endoscopic sinus surgery (ESS) was performed as treatment for recurrent nasal polyps. EC occurred while inhaled corticosteroids were reduced after ESS. Pathologic examination of the excised gallbladder demonstrated submucosal infiltration with a number of eosinophils. Furthermore, immunohistostaining revealed many galectin-10-positive cells in both the gallbladder mucosa and the paranasal sinus mucosa. Galectin-10 is a major constituent of human eosinophils, also known as the Charcot-Leyden crystal protein, which has been linked with eosinophilic inflammation. Interestingly, nasal polyps were reduced without any additional treatments 1 month after the cholecystectomy.

Conclusions

We experienced a rare case wherein EC onset occurred in a patient with refractory eosinophilic airway inflammation during inhaled corticosteroid tapering. Galectin-10 might help diagnose rare cases of eosinophilic inflammation in multiple organs.