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

IL-9 Induces CCL11 Expression via STAT3 Signalling in Human Airway Smooth Muscle Cells

Background: Previous findings support the concept that IL-9 may play a significant role in mediating both pro-inflammatory and changes in airway responsiveness that characterizes the atopic asthmatic state. We previously demonstrated that human airway smooth muscle (ASM) cells express a functional IL-9R that mediate CCL11 expression. However, the signaling pathway governing this effect is not well understood. Methodology/Principal Findings: In this study, we showed that IL-9 mediated CCL11 expression in ASM cells does not rely on STAT6 or STAT5 but on STAT3 pathway. IL-9 induced rapid STAT3 activation in primary ASM cells that was not observed in case of STAT6 or STAT5. STAT3 binding to CCL11 promoter was also observed in vivo upon IL-9 stimulation of ASM cells. Disruption of STAT3 activity with SH2 domain binding inhibitory peptide results in significant reduction of IL-9 mediated CCL11 promoter activity. DN STAT3b over-expression in ASM cells, but not Ser 727 STAT3 or STAT6 DN, abolishes IL-9 mediated CCL11 promoter activity. Finally, STAT3 but not STAT6 silenced ASM cells showed significant reduction in IL-9 mediated CCL11 promoter activity and mRNA expression. Conclusion/Significance: Taken together, our results indicate that IL-9 mediated CCL11 via STAT3 signalling pathway ma

Pentraxin 3 (PTX3) Expression in Allergic Asthmatic Airways: Role in Airway Smooth Muscle Migration and Chemokine Production

Pentraxin 3 (PTX3) is a soluble pattern recognition receptor with non-redundant functions in inflammation and innate immunity. PTX3 is produced by immune and structural cells. However, very little is known about the expression of PTX3 and its role in allergic asthma.We sought to determine the PTX3 expression in asthmatic airways and its function in human airway smooth muscle cells (HASMC). In vivo PTX3 expression in bronchial biopsies of mild, moderate and severe asthmatics was analyzed by immunohistochemistry. PTX3 mRNA and protein were measured by real-time RT-PCR and ELISA, respectively. Proliferation and migration were examined using (3)H-thymidine incorporation, cell count and Boyden chamber assays.PTX3 immunoreactivity was increased in bronchial tissues of allergic asthmatics compared to healthy controls, and mainly localized in the smooth muscle bundle. PTX3 protein was expressed constitutively by HASMC and was significantly up-regulated by TNF, and IL-1β but not by Th2 (IL-4, IL-9, IL-13), Th1 (IFN-γ), or Th-17 (IL-17) cytokines. In vitro, HASMC released significantly higher levels of PTX3 at the baseline and upon TNF stimulation compared to airway epithelial cells (EC). Moreover, PTX3 induced CCL11/eotaxin-1 release whilst inhibited the fibroblast growth factor-2 (FGF-2)-driven HASMC chemotactic activity.Our data provide the first evidence that PTX3 expression is increased in asthmatic airways. HASMC can both produce and respond to PTX3. PTX3 is a potent inhibitor of HASMC migration induced by FGF-2 and can upregulate CCL11/eotaxin-1 release. These results raise the possibility that PTX3 may play a dual role in allergic asthma

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

Downregulation of semaphorin 3E promotes hallmarks of experimental chronic allergic asthma

Guidance cues such as semaphorins are attractive novel therapeutic targets for allergic disorders. We have previously described an inhibitory effect of semaphorin 3E (Sema3E) on human airway smooth muscle cell function. We have further addressed a canonical role for Sema3E in acute model of allergic asthma in vivo. Considering the chronic nature of the disease, the potential implication of Sema3E to alleviate long-lasting deficits should be investigated. Expression of Sema3E in a chronic model of allergic asthma was assessed after exposure to house dust mite (HDM) as a clinically relevant allergen. Chronic features of allergic asthma including airway hyper-responsiveness (AHR), inflammation, and remodeling were studied in Sema3E-deficient mice. Additionally, the effect of exogenous Sema3E treatment was evaluated in prophylactic and therapeutic experimental models. We have demonstrated that expression of Sema3E is robustly suppressed in the airways upon chronic HDM exposure. Chronic allergic airway disease was significantly augmented in Sema3E-deficient mouse model which was associated with an increased AHR, remodeling, and Th2/Th17 inflammation. Intranasal Sema3E administration restored chronic deficits of allergic asthma in mice. Data from this study unveil a key regulatory role of Sema3E in chronic course of asthma via orchestration of impaired inflammatory and remodeling responses

IL-9 does not induce STAT6 nuclei translocation in human ASM cells.

<p>Growth arrested semi-confluent ASM cells were stimulated with IL-4 (A) or IL-9 (B) both at 10 ng/ml in 8 wells slide. Slides were stained with specific anti- phospho tyrosine STAT-6 mAb or isotype matched control, followed by goat anti-mouse IgG F(ab')₂ AlexaFluor® 488. Nuclear counter-staining was performed using TOTO-1 as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009178#s4" target="_blank">Materials and Methods</a>. Original magnification 400X.</p

IL-9 induces STAT3 phosphorylation and <i>in vivo</i> binding to CCL11 promoter in ASM cells.

<p>A–B. Cells were stimulated with IL-9 (A) or IL-4 (only 20 min is shown in B) and analyzed as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009178#pone-0009178-g001" target="_blank">Figure 1</a>. The data represent one of similar results from 5 independent experiments. C. IL-9 induced STAT3 binding to CCL11 promoter <i>in vivo</i>. Confluent and serum starved human ASM cells were treated with IL-4 (10 ng/ml) or IL-9 (10 ng/ml). The <i>in vivo</i> STAT3 binding to the CCL11 promoter was analyzed by ChIP assay as described under Material and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009178#s4" target="_blank">Methods</a>. The input represents PCR products from chromatin pellets prior to immunoprecipitation. The results are representative of three independent experiments with similar results. D. IL-9 driven STAT3 reporter gene activity. STAT3-specific reporter plasmid (p<i>Luc</i>TKS3) which harbors seven copies of a sequence corresponding to the STAT3-specific binding site was transfected into ASM cells or with pLucSRE serum response element (SRE) of the c-fos promoter (data not shown) following stimulation by IL-9 or IL-4 as described above. Data in D represent the mean ± SEM from a total of 5 independent experiments.</p

Effect of DN STAT3β, STAT3 Ser 727, or DN STAT6 over-expression on IL-9 induced CCL-11 promoter activity.

<p>Human primary ASM cells were co-transfected with WT-CCL-11 promoter and DN STAT3, STAT3β, STAT3 mutant at Ser 727 or DN STAT6. 24 h after transfection, cells were stimulated for 12 h with IL-4 or IL-9 (all at 10 ng/ml). Fold induction represents luciferase activity in cytokine treated cells compared to transfected untreated cells, and is the mean of five independent experiments. * P<0.05.</p