Pentraxin 3 (PTX3) expression in allergic asthmatic airways: role in airway smooth muscle migration and chemokine production

Pulmonary immune profiling reveals common inflammatory endotypes of childhood wheeze and suppurative lung disease

Suppurative lung disease and wheezing are common respiratory diseases of childhood, however, due to poor understanding of underlying pathobiology, there are limited treatment options and disease recurrence is common. We aimed to profile the pulmonary and systemic immune response in children with wheeze and chronic suppurative lung disease for identification of endotypes that can inform improved clinical management. We used clinical microbiology data, highly multiplexed flow cytometry and immunoassays to compare pulmonary [bronchoalveolar lavage (BAL)] and systemic immunity in children with lung disease and controls. Unsupervised analytical approaches were applied to BAL immune data to explore biological endotypes. We identified two endotypes that were analogous in both frequency and immune signature across both respiratory diseases. The hyper-inflammatory endotype had a 12-fold increase in neutrophil infiltration and upregulation of 14 soluble signatures associated with type 2 inflammation and cell recruitment to tissue. The non-inflammatory endotype was not significantly different from controls. We showed these endotypes are measurable in a clinical setting and can be defined by measuring only three immune factors in BAL. We identified hyper-inflammatory and non-inflammatory endotypes common across pediatric wheeze and chronic suppurative lung disease that, if validated in future studies, have the potential to inform clinical management.

Novel Serum Biomarkers for Patients with Allergic Asthma Phenotype

In distinguishing the allergic asthma (AA) phenotype, it has been identified that specific biomarkers could assist; however, none of them are considered ideal. This study aimed to analyze three groups of biologically active substances in the serum. Twenty steroid-free AA patients, sensitized to Dermatophagoides pteronyssinus, and sixteen healthy subjects (HSs) were enrolled in this study. Blood samples were collected from all patients. Additionally, all AA patients underwent a bronchial allergen challenge (BAC) with Dermatophagoides pteronyssinus, all of which were positive, and blood samples were collected again 24 h later. The concentrations of ten biologically active substances were measured in the serum samples, using enzyme-linked immunosorbent assay (ELISA) and the Luminex® 100/200™ System technology for bead-based multiplex and singleplex immunoassays. Descriptive and analytical statistical methods were used. A p-value of 0.05 or lower was considered statistically significant. The soluble interleukin 5 receptor subunit alpha (sIL-5Rα) and thioredoxin 1 (TRX1) concentrations were significantly increased, whereas those of tyrosine-protein kinase Met (MET), pentraxin 3 (PTX3), and I C-telopeptide of type I collagen (ICTP) were decreased in the AA group compared with the HS group. A significant positive correlation was noted for sIL-5Rα with fractional exhaled nitric oxide (FeNO), blood eosinophil (EOS) count, and total immunoglobulin E (IgE) levels, and a negative correlation was noted with forced expiratory volume in 1 s (FEV1). Moreover, PTX3 showed negative correlations with blood EOS count and total IgE levels, whereas ICTP exhibited a negative correlation with the blood EOS count. In conclusion, this study demonstrated that the serum concentrations of MET, PTX3, TRX1, ICTP, and particularly sIL-5Rα could potentially serve as biomarkers of the AA phenotype.

Pentraxin 3 Facilitates Shrimp-Allergic Responses in IgE-Activated Mast Cells

Background. Since food avoidance is currently the only way to prevent allergic reactions to shrimp, a better understanding of molecular events in the induction and progression of allergy, including food allergy, is needed for developing strategies to inhibit allergic responses. Pentraxin 3 (PTX3) is rapidly produced directly from inflammatory or damaged tissues and is involved in acute immunoinflammatory responses. However, the role of PTX3 in the development of immediate IgE-mediated shrimp allergy remains unknown. Methods. Wild-type BALB/c mice were immunized intraperitoneally and were challenged with shrimp extract. Serum IgE and PTX3 levels were analyzed. RBL-2H3 cells were stimulated with either dinitrophenyl (DNP) or serum of shrimp-allergic mice, and markers of degranulation, proinflammatory mediators, and phosphorylation of signal proteins were analyzed. We further examined the effect of PTX3 in shrimp extract-induced allergic responses in vitro and in vivo. Results. Mice with shrimp allergy had increased PTX3 levels in the serum and small intestine compared with healthy mice. PTX3 augmented degranulation, the production of proinflammatory mediators, and activation of the Akt and MAPK signaling pathways in mast cells upon DNP stimulation. Furthermore, the expression of transcription factor CCAAT/enhancer-binding protein delta (CEBPD) was elevated in PTX3-mediated mast cell activation. Finally, the PTX3 inhibitor RI37 could attenuate PTX3-induced degranulation, proinflammatory mediator expression, and phosphorylation of the Akt and MAPK signaling. Conclusions. The results suggested that PTX3 can facilitate allergic responses. Our data provide new insight to demonstrate that PTX3 is a cause of allergic inflammation and that RI37 can serve as a therapeutic agent in shrimp allergy.

New Insights on the Role of pentraxin-3 in Allergic Asthma

Pentraxins are soluble pattern recognition receptors that play a major role in regulating innate immune responses. Through their interaction with complement components, Fcγ receptors, and different microbial moieties, Pentraxins cause an amplification of the inflammatory response. Pentraxin-3 is of particular interest since it was identified as a biomarker for several immune-pathological diseases. In allergic asthma, pentraxin-3 is produced by immune and structural cells and is up-regulated by pro-asthmatic cytokines such as TNFα and IL-1β. Strikingly, some recent experimental evidence demonstrated a protective role of pentraxin-3 in chronic airway inflammatory diseases such as allergic asthma. Indeed, reduced pentraxin-3 levels have been associated with neutrophilic inflammation, Th17 immune response, insensitivity to standard therapeutics and a severe form of the disease. In this review, we will summarize the current knowledge of the role of pentraxin-3 in innate immune response and discuss the protective role of pentraxin-3 in allergic asthma.

Eosinophils as Major Player in Type 2 Inflammation: Autoimmunity and Beyond

Eosinophils are a subset of differentiated granulocytes which circulate in peripheral blood and home in several body tissues. Along with their traditional relevance in helminth immunity and allergy, eosinophils have been progressively attributed important roles in a number of homeostatic and pathologic situations. This review aims at summarizing available evidence about eosinophils functions in homeostasis, infections, allergic and autoimmune disorders, and solid and hematological cancers.Their structural and biological features have been described, along with their physiological behavior. This includes their chemokines, cytokines, granular contents, and extracellular traps. Besides, pathogenic- and eosinophilic-mediated disorders have also been addressed, with the aim of highlighting their role in Th2-driven inflammation. In allergy, eosinophils are implicated in the pathogenesis of atopic dermatitis, allergic rhinitis, and asthma. They are also fundamentally involved in autoimmune disorders such as eosinophilic esophagitis, eosinophilic gastroenteritis, acute and chronic eosinophilic pneumonia, and eosinophilic granulomatosis with polyangiitis. In infections, eosinophils are involved in protection not only from parasites but also from fungi, viruses, and bacteria. In solid cancers, local eosinophilic infiltration is variably associated with an improved or worsened prognosis, depending on the histotype. In hematologic neoplasms, eosinophilia can be the consequence of a dysregulated cytokine production or the result of mutations affecting the myeloid lineage.Recent experimental evidence was thoroughly reviewed, with findings which elicit a complex role for eosinophils, in a tight balance between host defense and tissue damage. Eventually, emerging evidence about eosinophils in COVID-19 infection was also discussed.

Endogenous Long Pentraxin 3 Exerts a Protective Role in a Murine Model of Pulmonary Fibrosis

Pulmonary fibrosis is a progressive scarring disease of the lungs, characterized by inflammation, fibroblast activation, and deposition of extracellular matrix. The long pentraxin 3 (PTX3) is a member of the pentraxin family with non-redundant functions in innate immune responses, tissue repair, and haemostasis. The role played in the lungs by PTX3 during the fibrotic process has not been elucidated. In this study, the impact of PTX3 expression on lung fibrosis was assessed in an intratracheal bleomycin (BLM)-induced murine model of the disease applied to wild type animals, transgenic mice characterized by endothelial overexpression and stromal accumulation of PTX3 (Tie2-PTX3 mice), and genetically deficient Ptx3^−/− animals. Our data demonstrate that PTX3 is produced during BLM-induced fibrosis in wild type mice, and that PTX3 accumulation in the stroma compartment of Tie2-PTX3 mice limits the formation of fibrotic tissue in the lungs, with reduced fibroblast activation and collagen deposition, and a decrease in the recruitment of the immune infiltrate. Conversely, Ptx3-null mice showed an exacerbated fibrotic response and decreased survival in response to BLM treatment. These results underline the protective role of endogenous PTX3 during lung fibrosis and pave the way for the study of novel PTX3-derived therapeutic approaches to the disease.

Perspectives on long pentraxin 3 and rheumatoid arthritis: several potential breakthrough points relying on study foundation of the past

Rheumatoid arthritis (RA) is a systemic chronic autoimmune inflammatory disease which is mainly characterized by synovitis and results in a severe burden for both the individual and society. To date, the underlying mechanisms of RA are still poorly understood. Pentraxin 3 (PTX3) is a typical long pentraxin protein which has been highly conserved during evolution. Meanwhile, functions as well as properties of PTX3 have been extensively studied. Several studies identified that PTX3 plays a predominate role in infection, inflammation, immunity and tumor. Interestingly, PTX3 has also been verified to be closely associated with development of RA. We therefore accomplished an elaboration of the relationships between PTX3 and RA. Herein, we mainly focus on the associated cell types and cognate cytokines involved in RA, in combination with PTX3. This review infers the insight into the interaction of PTX3 in RA and aims to provide novel clues for potential therapeutic target of RA in clinic.

Soluble pattern recognition molecules: Guardians and regulators of homeostasis at airway mucosal surfaces

Maintenance of homeostasis at body barriers that are constantly challenged by microbes, toxins and potentially bioactive (macro)molecules requires complex, highly orchestrated mechanisms of protection. Recent discoveries in respiratory research have shed light on the unprecedented role of airway epithelial cells (AEC), which, besides immune cells homing to the lung, also significantly contribute to host defence by expressing membrane‐bound and soluble pattern recognition receptors (sPRR). Recent evidence suggests that distinct, evolutionary ancient, sPRR secreted by AEC might become activated by usually innocuous proteins, commonly referred to as allergens. We here provide a systematic overview on sPRR detectable in the mucus lining of AEC. Some of them become actively produced and secreted by AECs (like the pentraxins C‐reactive protein and pentraxin 3; the collectins mannose binding protein and surfactant proteins A and D; H‐ficolin; serum amyloid A; and the complement components C3 and C5). Others are elaborated by innate and adaptive immune cells such as monocytes/macrophages and T cells (like the pentraxins C‐reactive protein and pentraxin 3; L‐ficolin; serum amyloid A; and the complement components C3 and C5). Herein we discuss how sPRRs may contribute to homeostasis but sometimes also to overt disease (e.g. airway hyperreactivity and asthma) at the alveolar–air interface.

Pentraxin 3 promotes airway inflammation in experimental asthma

Background

Pentraxin 3 (PTX3) regulates multiple aspects of innate immunity and tissue inflammation. Recently, it has been reported that PTX3 deficiency enhances interleukin (IL)-17A–dominant pulmonary inflammation in an ovalbumin (OVA)-induced mouse asthma model. However, whether PTX3 treatment would provide protection against allergic airway inflammation has not been clearly elucidated. The goal of this study was to further investigate the effect of recombinant PTX3 administration on the phenotype of asthma.

Methods

C57BL/6 J mice were sensitized and challenged with OVA to induce eosinophilic asthma model, as well as sensitized with OVA plus LPS and challenged with OVA to induce neutrophilic asthma model. We evaluated effect of recombinant PTX3 on asthma phenotype through both asthma models. The bronchoalveolar lavage fluid (BALF) inflammatory cells and cytokines, airway hyperresponsiveness, and pathological alterations of the lung tissues were assessed.

Results

In both eosinophilic and neutrophilic asthma models, PTX3 treatment provoked airway hyperresponsiveness, concomitant with increased inflammatory cytokines IL-4, IL-17, eotaxin, and transforming growth factor (TGF)-β1 and aggravated airway accumulation of inflammatory cells, especially eosinophils and neutrophils. In histological analysis of the lung tissue, administration of PTX3 promoted inflammatory cells infiltration, mucus production, and collagen deposition. In addition, PTX3 also significantly enhanced STAT3 phosphorylation in lung tissue.

Conclusion

Our results show that exogenous PTX3 can exacerbate multiple asthmatic features by promoting both eosinophils and neutrophils lung infiltration and provide new evidence to better understand the complex role of PTX3 in allergic airway inflammation.

FGF2, an Immunomodulatory Factor in Asthma and Chronic Obstructive Pulmonary Disease (COPD)

The fibroblast growth factor 2 (FGF2) is a potent mitogenic factor belonging to the FGF family. It plays a role in airway remodeling associated with chronic inflammatory airway diseases, including asthma and chronic obstructive pulmonary disease (COPD). Recently, research interest has been raised in the immunomodulatory function of FGF2 in asthma and COPD, through its involvement in not only the regulation of inflammatory cells but also its participation as a mediator between immune cells and airway structural cells. Herein, this review provides the current knowledge on the biology of FGF2, its expression pattern in asthma and COPD patients, and its role as an immunomodulatory factor. The potential that FGF2 is involved in regulating inflammation indicates that FGF2 could be a therapeutic target for chronic inflammatory diseases.

Glucocorticoids regulate pentraxin-3 expression in human airway smooth muscle cells

Pentraxin-3 (PTX3) is a multifunctional protein involved in both innate and adaptive immunity. Glucocorticoid (GC) is the first-line therapy to mitigate airway inflammation in asthma. Previous pieces of evidence showed that GC has divergent effects on PTX3 production in various cell types. The molecular mechanisms controlling PTX3 expression in HASMC are, however, not yet characterized. In this study, we demonstrate that the synthetic GC, dexamethasone (DEX) increases the expression of PTX3 both at the protein and mRNA levels. We also found that such an effect of DEX was dependent on de novo protein synthesis and the GC receptor (GR). While DEX increases PTX3 mRNA stability, it did not affect its promoter activity. Interestingly, HASMC pre-treated with p42/p44 ERK inhibitor, but not with p38 or JNK-MAPK inhibitors, significantly interfered with DEX-induced PTX3 secretion. Taken together, our data suggest that GC regulates PTX3 expression in HASMC through transcriptional and post-transcriptional mechanisms in a GR and ERK-dependent manner.

PTX3 Intercepts Vascular Inflammation in Systemic Immune-Mediated Diseases

PTX3 is a prototypic soluble pattern recognition receptor, expressed at sites of inflammation and involved in regulation of the tissue homeostasis. PTX3 systemic levels increase in many (but not all) immune-mediated inflammatory conditions. Research on PTX3 as a biomarker has so far focused on single diseases. Here, we performed a multi-group comparative study with the aim of identifying clinical and pathophysiological phenotypes associated with PTX3 release. PTX3 concentration was measured by ELISA in the plasma of 366 subjects, including 96 patients with giant cell arteritis (GCA), 42 with Takayasu's arteritis (TA), 10 with polymyalgia rheumatica (PMR), 63 with ANCA-associated systemic small vessel vasculitides (AAV), 55 with systemic lupus erythematosus (SLE), 21 with rheumatoid arthritis (RA) and 79 healthy controls (HC). Patients with SLE, AAV, TA and GCA, but not patients with RA and PMR, had higher PTX3 levels than HC. PTX3 concentration correlated with disease activity, acute phase reactants and prednisone dose. It was higher in females, in patients with recent-onset disease and in those with previous or current active vasculitis at univariate analysis. Active small- or large- vessel vasculitis were the main independent variables influencing PTX3 levels at multivariate analysis. High levels of PTX3 in the blood can contribute to identify an increased risk of vascular involvement in patients with systemic immune-mediated diseases.

Pentraxin levels in non-eosinophilic versus eosinophilic asthma

BACKGROUND

Innate immunity has been thought to be involved in asthma pathogenesis. Pentraxins, acting as soluble pattern recognition molecules, play an important role in humoral innate immunity. Asthma is a heterogeneous inflammatory disease of airways and can be classified as eosinophilic or non-eosinophilic asthma.

OBJECTIVE

To investigate whether pentraxin levels differ in subjects with eosinophilic versus non-eosinophilic asthma. Furthermore, to access the predictive performance of pentraxin levels for discriminating asthma inflammatory phenotypes.

METHODS

A total of 80 asthmatic patients and 24 healthy control subjects underwent sputum induction at study inclusion. Differential leucocyte counts were performed on selected sputum. Plasma C-reactive protein (CRP), serum amyloid P (SAP), pentraxin 3 (PTX3), and sputum SAP, PTX3, IL-8 levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Subjects with non-eosinophilic asthma had significantly increased pentraxin levels compared with those with eosinophilic asthma and healthy controls, with median (interquartile range) plasma CRP levels of 0.86 (0.28-2.07), 0.26 (0.14-0.85), and 0.15 (0.09-0.45)mg/L (P < .001), respectively, plasma SAP levels of 33.69 (19.79-58.39), 19.76 (16.11-30.58), and 20.06 (15.68-31.11)mg/L (P = .003), respectively, and sputum PTX3 levels of 4.9 (1.35-18.72), 0.87 (0.30-2.07), and 1.08 (0.31-4.32)ng/mL (P < .001), respectively. Conversely, sputum SAP concentrations of eosinophilic asthmatics (median, 21.49 ng/mL; IQR, 6.86-38.79 ng/mL) were significantly higher than those of non-eosinophilic patients (median, 8.15 ng/mL; IQR, 2.82-18.01 ng/mL) and healthy controls (median, 8.79 ng/mL; IQR, 2.00-16.18 ng/mL). Asthma patients with high plasma CRP (P = .004), SAP (P = .005) and sputum PTX3 levels (P < 0.001) also had significantly lower sputum eosinophil percentages. Sputum PTX3 levels had the best power (11.18-fold, P < .001) to predict non-eosinophilic airway inflammation in asthma patients.

CONCLUSION AND CLINICAL RELEVANCE

Pentraxin levels differed significantly between patients with non-eosinophilic asthma and those with eosinophilic asthma. Furthermore, elevated pentraxin expressions may predict non-eosinophilic airway inflammation in asthmatic patients.

Circulating levels of pentraxin-3 (PTX3) in patients with liver cirrhosis

BACKGROUND

Despite the circulating levels of PTX3 were related to the severity of various diseases, there are no studies investigating its role in patients with liver cirrhosis. We aimed to study PTX3 levels in patients with liver cirrhosis.

MATERIAL AND METHODS

A prospective cohort study included 130 patients hospitalized for acute decompensation of liver cirrhosis, 29 stable cirrhotic outpatients and 32 healthy controls evaluated in a tertiary hospital in Southern Brasil.

RESULTS

The median PTX3 level was significantly higher in stable cirrhotic patients compared to controls (2.6 vs. 1.1 ng/mL; p < 0.001), hospitalized cirrhotic patients compared to controls (3.8 vs. 1.1 ng/mL; p < 0.001), and hospitalized cirrhotic patients compared to stable cirrhotic patients (3.8 vs. 2.6 ng/mL; p = 0.001). A positive correlation was found between PTX3 and serum creatinine (r = 0.220; p = 0.012), Chronic Liver Failure - Sequential Organ Failure Assessment score (CLIF-SOFA) (r = 0.220; p = 0.010), MELD (r = 0.279; p = 0.001) and Child-Pugh score (r = 0.224; p = 0.010). Significantly higher levels of PTX3 were observed in patients on admission with ACLF (8.9 vs. 3.1 ng/mL; p < 0.001) and MELD score ≥ 20 (6.6 vs. 3.4 ng/mL; p = 0.002). Death within 90 days occurred in 30.8% of patients and was associated with higher levels of PTX3 (5.3 vs. 3.4 ng/mL; p = 0.009). The probability of Kaplan-Meier survival was 77.0% in patients with PTX-3 < 5.3 ng mL (upper tercile) and 53.5% in those with PTX3 ≥ 5.3 ng/mL (p = 0.002).

CONCLUSION

These results indicate the potential for use of PTX3 as an inflammatory biomarker for the prognosis of patients with hepatic cirrhosis.

Eosinophils from Physiology to Disease: A Comprehensive Review

Despite being the second least represented granulocyte subpopulation in the circulating blood, eosinophils are receiving a growing interest from the scientific community, due to their complex pathophysiological role in a broad range of local and systemic inflammatory diseases as well as in cancer and thrombosis. Eosinophils are crucial for the control of parasitic infections, but increasing evidence suggests that they are also involved in vital defensive tasks against bacterial and viral pathogens including HIV. On the other side of the coin, eosinophil potential to provide a strong defensive response against invading microbes through the release of a large array of compounds can prove toxic to the host tissues and dysregulate haemostasis. Increasing knowledge of eosinophil biological behaviour is leading to major changes in established paradigms for the classification and diagnosis of several allergic and autoimmune diseases and has paved the way to a "golden age" of eosinophil-targeted agents. In this review, we provide a comprehensive update on the pathophysiological role of eosinophils in host defence, inflammation, and cancer and discuss potential clinical implications in light of recent therapeutic advances.

Impaired response of the bronchial epithelium to inflammation characterizes severe equine asthma

BACKGROUND

Severe equine asthma is a naturally occurring lung inflammatory disease of mature animals characterized by neutrophilic inflammation, bronchoconstriction, mucus hypersecretion and airway remodeling. Exacerbations are triggered by inhalation of dust and microbial components. Affected animals eventually are unable of aerobic performance. In this study transcriptomic differences between asthmatic and non-asthmatic animals in the response of the bronchial epithelium to an inhaled challenge were determined.

RESULTS

Paired endobronchial biopsies were obtained pre- and post-challenge from asthmatic and non-asthmatic animals. The transcriptome, determined by RNA-seq and analyzed with edgeR, contained 111 genes differentially expressed (DE) after challenge between horses with and without asthma, and 81 of these were upregulated. Genes involved in neutrophil migration and activation were in central location in interaction networks, and related gene ontology terms were significantly overrepresented. Relative abundance of specific gene products as determined by immunohistochemistry was correlated with differential gene expression. Gene sets involved in neutrophil chemotaxis, immune and inflammatory response, secretion, blood coagulation and apoptosis were overrepresented among up-regulated genes, while the rhythmic process gene set was overrepresented among down-regulated genes. MMP1, IL8, TLR4 and MMP9 appeared to be the most important proteins in connecting the STRING protein network of DE genes.

CONCLUSIONS

Several differentially expressed genes and networks in horses with asthma also contribute to human asthma, highlighting similarities between severe human adult and equine asthma. Neutrophil activation by the bronchial epithelium is suggested as the trigger of the inflammatory cascade in equine asthma, followed by epithelial injury and impaired repair and differentiation. Circadian rhythm dysregulation and the sonic Hedgehog pathway were identified as potential novel contributory factors in equine asthma.

Lung inflammation after bleomycin treatment in mice: Selection of an accurate normalization strategy for gene expression analysis in an ex-vivo and in-vitro model

Pulmonary fibrosis (PF) is the most common and aggressive interstitial lung disease, characterized by a patchy development of fibrosis leading to progressive destruction of the normal lung architecture which is preceded by an inflammatory process. Gene expression studies are important to understand the development of PF but the accuracy and reproducibility of Real-Time PCR depend on appropriate normalization strategies. This study aimed to analyze the expression variability of eight commonly used reference genes during the initial inflammatory phase of bleomycin-induced PF in a mouse model and to verify whether the selected reference genes could be applied to an in-vitro model of BLM-treated primary murine lung fibroblasts. Wild-type C57BL/6 mice (n=40) were used. Real-Time PCR was carried out on lung tissue of mice either BLM (BLM-tm) or physiological solution-treated (PSS-tm), and in primary lung fibroblasts, isolated from healthy C57BL/6 mice. Histological analysis was performed to confirm the inflammation development. During inflammation, the most stable genes resulted: PPIA, HPRT-1 and SDHA for both models; the normalization strategy was tested analyzing mRNA expression of PTX-3 and TNF-α which resulted up-regulated both in ex-vivo and in-vitro with respect to PSS-tm/fibroblasts. Histological analysis supported the results. This study identified a new set of reference genes expressed both in the in-vitro and ex-vivo models. A higher expression of both markers in BLM-tm with respect to PSS-tm indicated that BLM might lead to increased PTX-3 local production by a co-regulation with TNF-α at lung level.

Protein phosphatase 5 mediates corticosteroid insensitivity in airway smooth muscle in patients with severe asthma

BACKGROUND

The mechanisms driving glucocorticoid (GC) insensitivity in patients with severe asthma are still unknown. Recent evidence suggests the existence of GC-insensitive pathways in airway smooth muscle (ASM) caused by a defect in GC receptor (GRα) function. We examined whether other mechanisms could potentially explain the reduced sensitivity of ASM cells to GC in severe asthmatics.

METHODS

Airway smooth muscle cells from healthy and severe asthmatic subjects were treated with TNF-α and responses to corticosteroids in both cohorts were compared by ELISA, immunoblot, immunohistochemistry and real-time PCR. Immunohistochemistry and flow cytometry assays were used to assess the expression of the protein phosphatase PP5 in endobronchial biopsies and ASM cells.

RESULTS

The production of CCL11 and CCL5 by TNF-α was insensitive to both fluticasone and dexamethasone in ASM cells from severe asthmatic compared to that in healthy subjects. Fluticasone-induced GRα nuclear translocation, phosphorylation at serine 211 and expression of GC-induced leucine zipper (GILZ) were significantly reduced in ASM cells from severe asthmatics compared to responses in healthy subjects. Levels of PP5 were increased in ASM cells from severe asthmatics and PP5 knockdown using siRNA restored fluticasone repressive action on chemokine production and its ability to induce GRα nuclear translocation and GRE-dependent GILZ expression. In vivo PP5 expression was also increased in the ASM bundles in endobronchial biopsies in severe asthmatics.

CONCLUSIONS

PP5-dependent impairment of GRα function represents a novel mechanism driving GC insensitivity in ASM in severe asthma.

Functional Effects of WNT1-Inducible Signaling Pathway Protein-1 on Bronchial Smooth Muscle Cell Migration and Proliferation in OVA-Induced Airway Remodeling

Upregulation of WISP1 has been demonstrated in lung remodeling. Moreover, it has been recently found that some signaling components of WNT pathway can activate GSK3β signaling to mediate remodeling of airway smooth muscle (ASM) in asthma. Therefore, we hypothesized that WISP1, a signaling molecule downstream of the WNT signaling pathway, is involved in PI3K/GSK3β signaling to mediate ASM remodeling in asthma. Our results showed that WISP1 depletion partly suppressed OVA-induced ASM hypertrophy in vivo. In vitro, WISP1 could induce hBSMC hypertrophy and proliferation, accompanied by upregulation of levels of PI3K, p-Akt, p-GSK3β, and its own expression. TGF-β treatment could increase expression of PI3K, p-Akt, p-GSK3β, and WISP1. SH-5 treatment could partly suppress TGF-β-induced hypertrophy and proliferation of hBSMC, and depress expression of p-GSK3β and WISP1. In conclusion, WISP1 may be a potential inducer of ASM proliferation and hypertrophy in asthma. The pro-remodeling effect of WISP1 is likely due to be involved in PI3K-GSK3β-dependent noncanonical TGF-β signaling.

Sputum pentraxin 3 as a candidate to assess airway inflammation and remodeling in childhood asthma

Pentraxin 3 (PTX3) is a soluble pattern recognition receptor and an acute-phase protein. It has gained attention as a new biomarker reflecting tissue inflammation and damage in a variety of diseases. Aim of this study is to investigate the role of PTX3 in childhood asthma.In total, 260 children (140 patients with asthma and 120 controls) were enrolled. PTX3 levels were measured in sputum supernatants using enzyme-linked immunosorbent assay test. We performed spirometry and methacholine challenge tests and measured the total eosinophil count and the serum levels of total IgE and eosinophil cationic protein (ECP) in all subjects.Sputum PTX3 concentration was significantly higher in children with asthma than in control subjects (P < 0.001). Furthermore, sputum PTX3 levels correlated with atopic status and disease severity among patients with asthma. A positive significant correlation was found between sputum PTX3 and the bronchodilator response (r = 0.25, P = 0.013). Sputum PTX3 levels were negatively correlated with forced expiratory volume in 1 second (FEV1) (r = -0.30, P = 0.001), FEV1/forced vital capacity (FVC) (r = -0.27, P = 0.002), and FEF25-75 (r = -0.392, P < 0.001), which are indicators of airway obstruction and inflammation. In addition, the PTX3 concentration in sputum showed negative correlations with post-bronchodilator (BD) FEV1 (r = -0.25, P < 0.001) and post-BD FEV1/FVC (r = -0.25, P < 0.001), which are parameters of persistent airflow limitation reflecting airway remodeling.Sputum PTX3 levels increased in children with asthma, suggesting that PTX3 in sputum could be a candidate molecule to evaluate airway inflammation and remodeling in childhood asthma.

Macrophages redirect phagocytosis by non-professional phagocytes and influence inflammation

Professional phagocytes (such as macrophages) and non-professional phagocytes (such as epithelial cells) clear billions of apoptotic cells and particles on a daily basis. Although professional and non-professional macrophages reside in proximity in most tissues, whether they communicate with each other during cell clearance, and how this might affect inflammation, is not known. Here we show that macrophages, through the release of a soluble growth factor and microvesicles, alter the type of particles engulfed by non-professional phagocytes and influence their inflammatory response. During phagocytosis of apoptotic cells or in response to inflammation-associated cytokines, macrophages released insulin-like growth factor 1 (IGF-1). The binding of IGF-1 to its receptor on non-professional phagocytes redirected their phagocytosis, such that uptake of larger apoptotic cells was reduced whereas engulfment of microvesicles was increased. IGF-1 did not alter engulfment by macrophages. Macrophages also released microvesicles, whose uptake by epithelial cells was enhanced by IGF-1 and led to decreased inflammatory responses by epithelial cells. Consistent with these observations, deletion of IGF-1 receptor in airway epithelial cells led to exacerbated lung inflammation after allergen exposure. These genetic and functional studies reveal that IGF-1- and microvesicle-dependent communication between macrophages and epithelial cells can critically influence the magnitude of tissue inflammation in vivo.

Role of PTX3 in corneal epithelial innate immunity against Aspergillus fumigatus infection

Pentraxin3 (PTX3), a member of long pentraxin family, plays a non-redundant role in human humoral innate immunity. However, whether PTX3 is expressed by corneal epithelial cells and its role during corneal fungi infection has not yet been investigated. To identify the presence of PTX3 in cornea, the possible mechanisms involved in its expression, and also the effects on corneal anti-fungi innate immune response, clinic human corneal tissues and cultured human corneal epithelial cells (HCECs) were resorted. PTX3 mRNA and protein were detected in corneal samples and cultured HCECs, which was significantly up-regulated after exposing to Aspergillus fumigatus (A. fumigatus). Pretreated with specific inhibitors, only Syk contributed to the regulation of PTX3 expression in Dectin-1/Syk signal axis. Furthermore, among the MAPK members (p38 MAPK, ERK1/2 and JNK), only ERK1/2 and JNK were responsible for A. fumigatus induced PTX3 production. Blocking of endogenous PTX3 by siRNA down-regulated the production of IL-1β at both mRNA and protein levels. Meanwhile, blocking of PTX3 also inhibited the phosphorylation of ERK1/2 and JNK, but not p38 MAPK. These findings demonstrate that PTX3 is expressed in human corneal epithelial cells and Syk, ERK1/2, JNK signaling pathways play an important role in the regulation of PTX3 induction. PTX3 plays a proinflammatory role in corneal epithelial anti-fungi immune response by affecting the production of IL-1β and activation of some proinflammatory signaling pathways (ERK1/2 and JNK).

Abnormal corticosteroid signalling in airway smooth muscle: mechanisms and perspectives for the treatment of severe asthma

Growing in vivo evidence supports the concept that airway smooth muscle produces various immunomodulatory factors that could contribute to asthma pathogenesis via the regulation of airway inflammation, airway narrowing and remodelling. Targeting ASM using bronchial thermoplasty has provided undeniable clinical benefits for patients with uncontrolled severe asthma who are refractory to glucocorticoid therapy. The present review will explain why the failure of glucocorticoids to adequately manage patients with severe asthma could derive from their inability to affect the immunomodulatory potential of ASM. We will support the view that ASM sensitivity to glucocorticoid therapy can be blunted in severe asthma and will describe some of the factors and mechanisms that could be responsible for glucocorticoid insensitivity.

Pentraxin 3 deletion aggravates allergic inflammation through a TH17-dominant phenotype and enhanced CD4 T-cell survival

Background

Pentraxin 3 (PTX3) is a multifunctional molecule that plays a nonredundant role at the crossroads between pathogen clearance, innate immune system, matrix deposition, female fertility, and vascular biology. It is produced at sites of infection and inflammation by both structural and inflammatory cells. However, its role in allergen-induced inflammation remains to be tested.

Objective

We sought to determine the effect of Ptx3 deletion on ovalbumin (OVA)–induced allergic inflammation in a murine model of asthma.

Methods

Bronchoalveolar lavage fluid was collected from patients with severe asthma and healthy subjects, and the level of PTX3 was determined by using ELISA. Ptx3^+/+ and Ptx3^−/− mice were sensitized and challenged with OVA and bronchoalveolar lavage fluid, and the lungs were collected for assessing inflammation. Lung tissue inflammation and mucus production were assessed by means of flow cytometry and hematoxylin and eosin and periodic acid-Schiff staining, respectively. flexiVent was used to determine airway resistance to methacholine in these mice.

Results

Here we report that mice with severe asthma and OVA-sensitized/challenged mice had increased PTX3 levels in the lungs compared with healthy control mice. Mice lacking PTX3 have exaggerated neutrophilic/eosinophilic lung inflammation, mucus production, and airway hyperresponsiveness in an experimental model of OVA-induced asthma. Furthermore, OVA-exposed lung Ptx3^−/− CD4 T cells exhibit an increased production of IL-17A, an effect that is accompanied by an increased signal transducer and activator of transcription 3 phosphorylation, reduced IL-2 production, and enhanced activation and survival. Also, we observed an increase in numbers of IL-6– and IL-23–producing dendritic cells in OVA-exposed Ptx3^−/− mice compared with those in wild-type control mice.

Conclusion

Altogether, PTX3 deficiency results in augmented airway hyperresponsiveness, mucus production, and IL-17A–dominant pulmonary inflammation, suggesting a regulatory role of PTX3 in the development of allergic inflammation.

Dysregulated function of normal human epidermal keratinocytes in the absence of filaggrin

The aim of the present study was to investigate the impact of filaggrin knockdown on the function of normal human epidermal keratinocytes (NHEKs). Filaggrin expression levels in NHEKs were knocked down by lentivirus (LV) encoding small hairpin RNA (shRNA), with control cells infected with nonsense shRNA or not infected. Cell migration and invasion were assayed using Transwell inserts, cell adhesion and proliferation by the Cell Counting kit-8 assay, and apoptosis and cell cycle progression by flow cytometry. shRNA efficiently suppressed expression of filaggrin protein. The LV group had significantly decreased cell migration, adhesion and proliferation, and increased apoptosis compared with the control groups (P=0.027). In addition, the proportion of cells in G₁ and G₂ phases were significantly increased in the LV group compared with control groups (P=0.018). The results of the present study demonstrate that filaggrin knockdown inhibits NHEK migration, adhesion and proliferation, promotes apoptosis and disturbs cell cycle progression.

Activin-A is overexpressed in severe asthma and is implicated in angiogenic processes

Activin-A is a pleiotropic cytokine that regulates allergic inflammation. Its role in the regulation of angiogenesis, a key feature of airways remodelling in asthma, remains unexplored. Our objective was to investigate the expression of activin-A in asthma and its effects on angiogenesis in vitro.Expression of soluble/immunoreactive activin-A and its receptors was measured in serum, bronchoalveolar lavage fluid (BALF) and endobronchial biopsies from 16 healthy controls, 19 patients with mild/moderate asthma and 22 severely asthmatic patients. In vitro effects of activin-A on baseline and vascular endothelial growth factor (VEGF)-induced human endothelial cell angiogenesis, signalling and cytokine release were compared with BALF concentrations of these cytokines in vivo.Activin-A expression was significantly elevated in serum, BALF and bronchial tissue of the asthmatics, while expression of its protein receptors was reduced. In vitro, activin-A suppressed VEGF-induced endothelial cell proliferation and angiogenesis, inducing autocrine production of anti-angiogenic soluble VEGF receptor (R)1 and interleukin (IL)-18, while reducing production of pro-angiogenic VEGFR2 and IL-17. In parallel, BALF concentrations of soluble VEGFR1 and IL-18 were significantly reduced in severe asthmatics in vivo and inversely correlated with angiogenesis.Activin-A is overexpressed and has anti-angiogenic effects in vitro that are not propagated in vivo, where reduced basal expression of its receptors is observed particularly in severe asthma.

Tumor Necrosis Factor, but Not Neutrophils, Alters the Metabolic Profile in Acute Experimental Arthritis

Metabolic alterations are associated with arthritis apart from obesity. However, it is still unclear which is the underlying process behind these metabolic changes. Here, we investigate the role of tumor necrosis factor (TNF) in this process in an acute model of antigen-induced arthritis (AIA). Immunized male BALB/c mice received an intra-articular injection of PBS (control) or methylated bovine serum albumin (mBSA) into their knees, and were also pre-treated with different drugs: Etanercept, an anti-TNF drug, DF2156A, a CXCR1/2 receptor antagonist, or a monoclonal antibody RB6-8C5 to deplete neutrophils. Local challenge with mBSA evoked an acute neutrophil influx into the knee joint, and enhanced the joint nociception, along with a transient systemic metabolic alteration (higher levels of glucose and lipids, and altered adipocytokines). Pre-treatment with the conventional biological Etanercept, an inhibitor of TNF action, ameliorated the nociception and the acute joint inflammation dominated by neutrophils, and markedly improved many of the altered systemic metabolites (glucose and lipids), adipocytokines and PTX3. However, the lessening of metabolic changes was not due to diminished accumulation of neutrophils in the joint by Etanercept. Reduction of neutrophil recruitment by pre-treating AIA mice with DF2156A, or even the depletion of these cells by using RB6-8C5 reduced all of the inflammatory parameters and hypernociception developed after AIA challenge, but could not prevent the metabolic changes. Therefore, the induction of joint inflammation provoked acute metabolic alterations which were involved with TNF. We suggest that the role of TNF in arthritis-associated metabolic changes is not due to local neutrophils, which are the major cells present in this model, but rather due to cytokines.

TNF up-regulates Pentraxin3 expression in human airway smooth muscle cells via JNK and ERK1/2 MAPK pathways

BACKGROUND

Long pentraxin 3 (PTX3) is a novel candidate marker for inflammation in many chronic diseases. As a soluble pattern recognition receptor, PTX3 is involved in amplification of inflammatory reactions and regulation of innate immunity. Previously, we demonstrate that human airway smooth muscle cells (HASMC) express constitutively PTX3 and upon TNF stimulation. However, very little is known about the mechanism governing its expression in HASMC. We sought to investigate the mechanism governing TNF induced PTX3 expression in primary HASMC.

METHODS

HASMC were stimulated with TNF in the presence of transcriptional inhibitor actinomycin D (ActD) or MAPKs pharmacological inhibitors. PTX3 mRNA and protein expression were analyzed by Real-time RT-PCR and ELISA, respectively. PTX3 promoter activity was determined using luciferase assay.

RESULTS

PTX3 mRNA and protein are expressed constitutively by HASMC and significantly up-regulated by TNF. TNF-induced PTX3 mRNA and protein release in HASMC were inhibited by transcriptional inhibitor actinomycin D. TNF induced significantly PTX3 promoter activation in HASMC. MAPK JNK and ERK1/2 specific inhibitors (SP600125 and UO126), but not p38, significantly down regulates TNF induced PTX3 promoter activity and protein release in HASMC. Finally, TNF mediated PTX3 promoter activity in HASMC was abolished upon mutation of NF-κβ and AP1 binding sites.

CONCLUSIONS

Our data suggest that TNF induced PTX3 in HASMC at least via a transcriptional mechanism that involved MAPK (JNK and ERK1/2), NF-κβ and AP1 pathways. These results rise the possibility that HASMC derived PTX3 may participate in immune regulation in the airways.

Pentraxin 3 sputum levels differ in patients with chronic obstructive pulmonary disease vs asthma

BACKGROUND

Immune response has been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD) and asthma. Pentraxin 3 (PTX3) is a multifunctional pattern recognition protein and an important component of the innate immune system that can be assessed in blood and induced sputum.

OBJECTIVE

To determine whether PTX3 measured in induced sputum could discriminate patients with COPD from patients with asthma.

METHODS

A cross-sectional study of 68 participants (27 with COPD, 25 with asthma, and 16 healthy controls) was performed. At study inclusion sputum was collected and total and differential cell numbers and PTX3 levels were determined.

RESULTS

Pentraxin 3 was detected in 89% of patients with COPD, 56% of patients with asthma, and 19% of controls (P = .001). It discriminated participants with COPD (24.6 ng/mL, 0-384 ng/mL) from controls (0 ng/mL, 0-36 ng/mL, P < .001) and from participants with asthma (1.2 ng/mL, 0-100 ng/mL, P = .01; area under the receiver operating curve 0.82 [0.71-0.94]). Regression analyses determined that sputum PTX3 and neutrophil counts were independently associated with COPD. In addition, PTX3 levels were independently associated with COPD severity.

CONCLUSION

Pentraxin 3 sputum levels are increased in patients with COPD and has good power to discriminate these patients from patients with asthma and healthy individuals.

IL-6 trans-signaling increases expression of airways disease genes in airway smooth muscle

Genetic data suggest that IL-6 trans-signaling may have a pathogenic role in the lung; however, the effects of IL-6 trans-signaling on lung effector cells have not been investigated. In this study, human airway smooth muscle (HASM) cells were treated with IL-6 (classical) or IL-6+sIL6R (trans-signaling) for 24 h and gene expression was measured by RNAseq. Intracellular signaling and transcription factor activation were assessed by Western blotting and luciferase assay, respectively. The functional effect of IL-6 trans-signaling was determined by proliferation assay. IL-6 trans-signaling had no effect on phosphoinositide-3 kinase and Erk MAP kinase pathways in HASM cells. Both classical and IL-6 trans-signaling in HASM involves activation of Stat3. However, the kinetics of Stat3 phosphorylation by IL-6 trans-signaling was different than classical IL-6 signaling. This was further reflected in the differential gene expression profile by IL-6 trans-signaling in HASM cells. Under IL-6 trans-signaling conditions 36 genes were upregulated, including PLA2G2A, IL13RA1, MUC1, and SOD2. Four genes, including CCL11, were downregulated at least twofold. The expression of 112 genes was divergent between IL-6 classical and trans-signaling, including the genes HILPDA, NNMT, DAB2, MUC1, WWC1, and VEGFA. Pathway analysis revealed that IL-6 trans-signaling induced expression of genes involved in regulation of airway remodeling, immune response, hypoxia, and glucose metabolism. Treatment of HASM cells with IL-6+sIL6R induced proliferation in a dose-dependent fashion, suggesting a role for IL-6 trans-signaling in asthma pathogenesis. These novel findings demonstrate differential effect of IL-6 trans-signaling on airway cells and identify IL-6 trans-signaling as a potential modifier of airway inflammation and remodeling.

The long pentraxin PTX3 promotes fibrocyte differentiation

Monocyte-derived, fibroblast-like cells called fibrocytes are associated with fibrotic lesions. The plasma protein serum amyloid P component (SAP; also known as pentraxin-2, PTX2) inhibits fibrocyte differentiation in vitro, and injections of SAP inhibit fibrosis in vivo. SAP is a member of the pentraxin family of proteins that includes C-reactive protein (CRP; PTX1) and pentraxin-3 (PTX3). All three pentraxins are associated with fibrosis, but only SAP and CRP have been studied for their effects on fibrocyte differentiation. We find that compared to SAP and CRP, PTX3 promotes human and murine fibrocyte differentiation. The effect of PTX3 is dependent on FcγRI. In competition studies, the fibrocyte-inhibitory activity of SAP is dominant over PTX3. Binding competition studies indicate that SAP and PTX3 bind human FcγRI at different sites. In murine models of lung fibrosis, PTX3 is present in fibrotic areas, and the PTX3 distribution is associated with collagen deposition. In lung tissue from pulmonary fibrosis patients, PTX3 has a widespread distribution, both in unaffected tissue and in fibrotic lesions, whereas SAP is restricted to areas adjacent to vessels, and absent from fibrotic areas. These data suggest that the relative levels of SAP and PTX3 present at sites of fibrosis may have a significant effect on the ability of monocytes to differentiate into fibrocytes.

Thymic stromal lymphopoietin induces migration in human airway smooth muscle cells

Airway remodeling due to increased airway smooth muscle (ASM) mass, likely due to enhanced migration and proliferation, has been shown to be highly associated with decline in lung function in asthma. Thymic stromal lymphopoietin (TSLP) is an IL-7-like, pro-allergic cytokine that has been shown to be necessary and sufficient for the development of allergic asthma. Human ASM (HASM) cells express TSLP receptor (TSLPR), the activation of which leads to enhanced release of proinflammatory mediators such as IL-6, CCL11/eotaxin-1, and CXCL8/IL-8. We show here that TSLP induces HASM cell migration through STAT3 activation since lentiviral-shRNA inhibition of STAT3 abrogated the TSLP-induced cell migration. Moreover, TSLP induced multiple cytoskeleton changes in HASM cells such as actin polymerization, cell polarization, and activation of small GTPase Rac1. Collectively, our data suggest a pro-migratory function of TSLP in ASM remodeling and provides better rationale for targeting TSLP/TSLPR pathway for therapeutic approaches in allergic asthma.

Pentraxin 3: an immuno-regulator in the lungs

Pentraxin 3 (PTX3) is a soluble pattern recognition receptor that is a humoral component of the innate immune system. It interacts with pathogenic moieties, infected and dying host cells and facilitates their removal through activation of appropriate innate and adaptive mechanisms. PTX3 is secreted by a diverse variety of cells, ranging from immune cells to structural cells, in response to Toll like receptor (TLR) engagement, inflammatory stimuli, and physical and chemical stress. Further, PTX3 plays an essential role in female fertility as it facilitates the organization of extracellular matrix in the cumulus oophorus. Such activity is also implicated in post-inflammation tissue repair. PTX3 is a multifunctional protein and plays a non-redundant role in providing immunity against potential immunological dangers. Thus, we assessed its role in lung immunity, as lungs are at a constant risk of infections and tissue damage that is attributable to perpetual exposure to foreign agents.