IL-9 in allergic inflammation

The emerging role of T helper 9 (Th9) cells in immunopathophysiology: A comprehensive review of their effects and responsiveness in various disease states

Th9 cells, a subset of T-helper cells producing interleukin-9 (IL-9), play a vital role in the adaptive immune response and have diverse effects in different diseases. Regulated by transcription factors like PU.1 and IRF4, and cytokines such as IL-4 and TGF-β, Th9 cells drive tissue inflammation. This review focuses on their emerging role in immunopathophysiology. Th9 cells exhibit immune-mediated cancer cell destruction, showing promise in glioma and cervical cancer treatment. However, their role in breast and lung cancer is intricate, requiring a deeper understanding of pro- and anti-tumor aspects. Th9 cells, along with IL-9, foster T cell and immune cell proliferation, contributing to autoimmune disorders. They are implicated in psoriasis, atopic dermatitis, and infections. In allergic reactions and asthma, Th9 cells fuel pro-inflammatory responses. Targeting Foxo1 may regulate innate and adaptive immune responses, alleviating disease symptoms. This comprehensive review outlines Th9 cells' evolving immunopathophysiological role, emphasizing the necessity for further research to grasp their effects and potential therapeutic applications across diseases.

Atopy in chronic urticaria: an important yet overlooked issue

Chronic urticaria (CU) is one of the most common dermatological diseases and has a significant impact on the quality of life of patients. However, the pathogenesis of this disease remains unclear. Autoimmunity in chronic spontaneous urticaria (CSU) has received considerable attention and has been studied previously. Atopy is an important characteristic of CU; however, it has not been fully recognized. Atopy predisposes individuals to immune responses to allergens, leading to type 2 inflammation and immunoglobulin E (IgE) overproduction. Compared with healthy individuals, patients with CU have a higher proportion of atopy, and an atopic background is correlated with the clinical characteristics of CU. The total IgE levels in patients with CU is significantly higher than those in healthy individuals. Although its level is not higher than that in classic allergic diseases, it is closely related to CU. Exogenous allergens, auto-allergens, and specific IgEs, which are closely related to atopy, have been reported, and their roles in CU pathogenesis are also being studied. Local and systemic atopic inflammation is present in patients with CU. This review summarizes the current knowledge regarding atopy and CU, speculating that there are CU subtypes, such as atopic CSU or atopic chronic inducible urticaria (CIndU) and that atopy may be involved in the pathogenesis of CU. These findings provide a new perspective for a comprehensive understanding of the clinical features of CU and further research regarding its pathogenesis.

Intervertebral disc degeneration and inflammatory microenvironment: expression, pathology, and therapeutic strategies

BACKGROUND

Intervertebral disc degeneration (IDD) is a leading cause of low back pain (LBP), posing a significant socioeconomic burden. Recent studies highlight the crucial role of inflammatory microenvironment in IDD progression.

METHOD

A keyword-based search was performed using the PubMed database for published articles.

RESULTS AND CONCLUSIONS

Dysregulated expression of inflammatory cytokines disrupts intervertebral disc (IVD) homeostasis, causing atrophy, fibrosis, and phenotypic changes in nucleus pulposus cells. Modulating the inflammatory microenvironment and restoring cytokine balance hold promise for IVD repair and regeneration. This comprehensive review systematically examines the expression regulation, pathological effects, therapeutic strategies, and future challenges associated with the inflammatory microenvironment and relevant cytokines in IDD. Key inflammatory cytokines, including interleukins (IL), tumor necrosis factor-alpha (TNF-α), and chemokines, exhibit significant pathological effects in IDD. Furthermore, major therapeutic modalities such as chemical antagonists, biologics, plant extracts, and gene transcription therapies are introduced to control and ameliorate the inflammatory microenvironment. These approaches provide valuable insights for identifying potential targets in future anti-inflammatory treatments for IDD.

Regulatory Effect of Inflammatory Mediators in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IDD) is a major contributor to back, neck, and radicular pain. It is related to changes in tissue structure and function, including the breakdown of the extracellular matrix (ECM), aging, apoptosis of the nucleus pulposus, and biomechanical tissue impairment. Recently, an increasing number of studies have demonstrated that inflammatory mediators play a crucial role in IDD, and they are being explored as potential treatment targets for IDD and associated disorders. For example, interleukins (IL), tumour necrosis factor-α (TNF-α), chemokines, and inflammasomes have all been linked to the pathophysiology of IDD. These inflammatory mediators are found in high concentrations in intervertebral disc (IVD) tissues and cells and are associated with the severity of LBP and IDD. It is feasible to reduce the production of these proinflammatory mediators and develop a novel therapy for IDD, which will be a hotspot of future research. In this review, the effects of inflammatory mediators in IDD were described.

Characterization of the Transient Deficiency of PKC Isozyme Levels in Immature Cord Blood T Cells and Its Connection to Anti-Allergic Cytokine Profiles of the Matured Cells

Cord blood T cells (CBTC) from a proportion of newborns express low/deficient levels of some protein kinase C (PKC) isozymes, with low levels of PKCζ correlating with increased risk of developing allergy and associated decrease in interferon-gamma (IFN-γ) producing T cells. Interestingly, these lower levels of PKCζ were increased/normalized by supplementing women during pregnancy with n-3 polyunsaturated fatty acids. However, at present, we have little understanding of the transient nature of the deficiency in the neonate and how PKCζ relates to other PKC isozymes and whether their levels influence maturation into IFN-γ producing T cells. There is also no information on PKCζ isozyme levels in the T cell subpopulations, CD4⁺ and CD8⁺ cells. These issues were addressed in the present study using a classical culture model of neonatal T cell maturation, initiated with phytohaemagglutinin (PHA) and recombinant human interleukin-2 (rhIL-2). Of the isozymes evaluated, PKCζ, β2, δ, μ, ε, θ and λ/ι were low in CBTCs. The PKC isozyme deficiencies were also found in the CD4⁺ and CD8⁺ T cell subset levels of the PKC isozymes correlated between the two subpopulations. Examination of changes in the PKC isozymes in these deficient cells following addition of maturation signals showed a significant increase in expression within the first few hours for PKCζ, β2 and μ, and 1–2 days for PKCδ, ε, θ and λ/ι. Only CBTC PKCζ isozyme levels correlated with cytokine production, with a positive correlation with IFN-γ, interleukin (IL)-2 and tumour necrosis factor-alpha (TNF), and a negative association with IL-9 and IL-10. The findings reinforce the specificity in using CBTC PKCζ levels as a biomarker for risk of allergy development and identify a period in which this can be potentially ‘corrected’ after birth.

Cord Blood T Cells Expressing High and Low PKCζ Levels Develop into Cells with a Propensity to Display Th1 and Th9 Cytokine Profiles, Respectively

Low Protein Kinase C zeta (PKCζ) levels in cord blood T cells (CBTC) have been shown to correlate with the development of allergic sensitization in childhood. However, little is known about the mechanisms responsible. We have examined the relationship between the expression of different levels of PKCζ in CBTC and their development into mature T cell cytokine producers that relate to allergy or anti-allergy promoting cells. Maturation of naïve CBTC was initiated with anti-CD3/-CD28 antibodies and recombinant human interleukin-2 (rhIL-2). To stimulate lymphocyte proliferation and cytokine production the cells were treated with Phytohaemagglutinin (PHA) and Phorbol myristate acetate (PMA). Irrespective of the PKCζ levels expressed, immature CBTC showed no difference in lymphocyte proliferation and the production of T helper 2 (Th2) cytokine interleukin-4 (IL-4) and Th1 cytokine, interferon-gamma (IFN-γ), and influenced neither their maturation from CD45RA⁺ to CD45RO⁺ cells nor cell viability/apoptosis. However, upon maturation the low PKCζ expressing cells produced low levels of the Th1 cytokines, IFN-γ, IL-2 and tumour necrosis factor-alpha (TNF), no changes to levels of the Th2 cytokines, IL-4, IL-5 and IL-13, and an increase in the Th9 cytokine, IL-9. Other cytokines, lymphotoxin-α (LT-α), IL-10, IL-17, IL-21, IL-22 and Transforming growth factor-beta (TGF-β) were not significantly different. The findings support the view that low CBTC PKCζ levels relate to the increased risk of developing allergic diseases.

Antibody-based delivery of interleukin-9 to neovascular structures: Therapeutic evaluation in cancer and arthritis

Interleukin-9 is a cytokine with multiple functions, including the ability to activate group 2 innate lymphoid cells, which has been postulated to be therapeutically active in mouse models of arthritis. Similarly, interleukin-9 has been suggested to play an important role in tumor immunity. Here, we describe the cloning, expression, and characterization of three fusion proteins based on murine interleukin-9 and the F8 antibody, specific to the alternatively spliced EDA domain of fibronectin. EDA is strongly expressed in cancer and in various arthritic conditions, while being undetectable in the majority of healthy organs. Interleukin-9-based fusion proteins with an irrelevant antibody specific to hen egg lysozyme served as negative control in our study. The fusion proteins were characterized by quantitative biodistribution analysis in tumor-bearing mice using radioiodinated protein preparations. The highest tumor uptake and best tumor:organ ratios were observed for a format, in which the interleukin-9 moiety was flanked by two units of the F8 antibody in single-chain Fv format. Biological activity of interleukin-9 was retained when the payload was fused to antibodies. However, the targeted delivery of interleukin-9 to the disease site resulted in a modest anti-tumor activity in three different murine models of cancer (K1735M2, CT26, and F9), while no therapeutic benefit was observed in a collagen induced model of arthritis. Collectively, these results confirm the possibility to deliver interleukin-9 to the site of disease but cast doubts about the alleged therapeutic activity of this cytokine in cancer and arthritis, which has been postulated in previous publications.

Interaction between regulatory T cells and mast cells via IL-9 and TGF-β production

Research on the immunosuppression of cancer cells has attracted much attention in recent years. The present study sought to provide a new strategy for tumor immunotherapy targeting mast cells by studying the mechanisms underlying mast cell function in cancer immunosuppression. Between January 2015 and December 2017, the tumor tissues of 40 patients with gastric cancer (GC) were collected and grouped in Lihuili Hospital of Ningbo City, China. Pathological sections were prepared and an immunofluorescence assay was performed to analyze the expression of forkhead Box Protein P3 (FOXP3), tryptase, TGFβ1, TGF-βR, IL-9, IL-9R and Oxford 40 ligand (OX40L). Then, the correlations between FOXP3 and tryptase, TGFβ1 and tryptase expression, and the expression of OX40L in patients with GC with different stages were analyzed. The results revealed that high levels of mast cells were present in patients GC, and tryptase and FOXP3 expressions were positively correlated. Mast cells regulate T regulatory (reg) cells in the gastric tumor microenvironment by secreting TGFβ1. Tregs, in turn, promote the survival of mast cells in the tumor microenvironment by producing IL-9. Furthermore, OX40L expression in mast cells was significantly associated with Tumor-Node-Metastasis staging of GC. Overall, the present study reported a positive feedback system that functions through TGFβ1 and IL-9 to allow cross-talk between Tregs and mast cells. Moreover, OX40L may be a potential target for the diagnosis and treatment of GC. These results may provide a new strategy for tumor immunotherapy targeting mast cells.

Cytokine Profile in Human Peripheral Blood Mononuclear Leukocytes Exposed to Immunoadjuvant and Adjuvant-Free Vaccines Against Influenza

Background: In the last decade, adjuvant-containing vaccines, exerting different effects on the immune system, including the production of cytokines, which are one of the most important regulatory systems of the body, are introduced into practice. Objectives: An effect of the immunoadjuvant polymer-subunit and adjuvant-free vaccines against influenza on the cytokine profile of mononuclear leukocytes in 27 healthy women was studied. Methods: The study of cytokine profile in human peripheral blood mononuclear leukocytes exposed to vaccines against influenza virus was determined by flow cytometry method (Cytomix FC-500, Beckman Coulter, USA) using the Multiplex-13 test system (Bender MedSystems, Austria). Results: It was established that all the studied vaccines leaded to somewhat increased levels of Th1/Th2/Th17/Th9/Th22 cytokines in the culture fluid of peripheral blood mononuclear leukocytes (PBML), which indicates the activation of both humoral and cellular immunity. An immunoadjuvant vaccine has been shown to be superior in activating the synthesis of Th1 (IL-12, INF-g, IL-2, IL-6, IL-1β, TNF-α) cytokines, IL-9 and IL-22, while the subunit vaccine was superior in activating the synthesis of IL-4, and split vaccine-of IL-5. Conclusions: Immunoadjuvant vaccine is superior in terms of inducing cellular immune effectors to a greater extent compared to subunit and split vaccines.

Interleukin 9 Alters Epithelial Barrier and E-cadherin in Eosinophilic Esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic TH2-assocated inflammatory condition accompanied by substantial impairments in epithelial barrier function and increased numbers of interleukin 9 (IL-9) expressing inflammatory cells. While IL-9 is known to affect barrier function in the intestine, the functional effects of IL-9 on the esophagus are unclear. Herein we aimed to understand the expression of the IL-9 receptor and effects of IL-9 on the epithelium in EoE.

METHODS

We used esophageal biopsies from pediatric EoE patients with active and inactive disease to analyze the expression of the IL-9 receptor, the adherens junction protein E-cadherin and the tight junction protein claudin-1. We treated primary human esophageal epithelial cells with IL-9 to understand its effects on E-cadherin expression and function.

RESULTS

Active EoE subjects had increased epithelial expression of IL-9 receptor mRNA and protein (P < 0.05) and decreased membrane bound E-cadherin (P < 0.01) and claudin-1 (P < 0.05) expression. IL-9 receptor expression and mislocalized claudin-1 positively correlated and while membrane bound E-cadherin expression negatively correlated with the degree of histologic epithelial remodeling (P < 0.05). IL-9 decreased epithelial resistance in stratified primary human esophageal epithelial cells (P < 0.01) and membrane bound E-cadherin in epithelial cell monolayers (P < 0.01).

CONCLUSIONS

These data suggest that IL-9, its receptor, and its effects on E-cadherin may be important mechanisms for epithelial barrier disruption in EoE.

Effect of wild grape on the signaling of histamine H1 receptor gene expression responsible for the pathogenesis of allergic rhinitis

As expression level of allergic disease-sensitive genes are correlated with allergic symptom severity, suppression of these gene expressions could be good therapeutics. We have demonstrated that PKCδ signaling and NFAT signaling, involve in histamine H₁ receptor (H1R) and IL-9 gene expressions, respectively, are responsible for the pathogenesis of allergic rhinitis. We explore anti-allergic compounds that suppress these signaling pathways and found that wild grape (WG) contains such compounds. Here, we investigated the effect of WG hot water extract (WGE) on the signaling pathways for PKCδ-mediated H1R and NFAT-mediated IL-9 gene expressions. WGE suppressed histamine/PMA-induced H1R gene up-regulation in HeLa cells. Toluene-2,4-diisocyanate (TDI)-induced H1R mRNA elevation in TDI-sensitized rats was also suppressed by WGE treatment. Treatment with WGE in combination with Awa-tea, suppresses NFAT signaling-mediated IL-9 gene, markedly alleviated nasal symptoms. Furthermore, WGE suppressed PMA-induced IL-33 gene up-regulation in Swiss 3T3 cells. Data suggest that combination of WGE, suppresses PKCδ signaling with Awa-tea, suppresses NFAT signaling would have distinct clinical and therapeutic advantages as a substitute for anti-allergic drugs. In addition, as the expression level of IL-33 mRNA was correlated with the blood eosinophils number in patients with pollinosis, WG could alleviate eosinophilic inflammation through the suppression of IL-33 gene expression. J. Med. Invest. 65:242-250, August, 2018.

Effect of Royal Jelly and Brazilian Green Propolis on the Signaling for Histamine H1 Receptor and Interleukin-9 Gene Expressions Responsible for the Pathogenesis of the Allergic Rhinitis

The significant correlation between nasal symptom scores and level of histamine H₁ receptor (H1R) mRNA in nasal mucosa was observed in patients with pollinosis, suggesting that H1R gene is an allergic disease sensitive gene. We demonstrated that H1R and interleukin (IL)-9 gene are the allergic rhinitis (AR)-sensitive genes and protein kinase Cδ (PKCδ) signaling and nuclear factor of activated T-cells (NFAT) signaling are involved in their expressions, respectively. Honey bee products have been used to treat allergic diseases. However, their pathological mechanism remains to be elucidated. In the present study, we investigated the mechanism of the anti-allergic effect of royal jelly (RJ) and Brazilian green propolis (BGPP). Treatment with RJ and BGPP decreased in the number of sneezing on toluene 2,4-diissocyanate (TDI)-stimulated rats. The remarkable suppression of H1R mRNA in nasal mucosa was observed. RJ and BGPP also suppressed the expression of IL-9 gene. RJ and BGPP suppressed phorbol-12-myristate-13-acetate-induced Tyr³¹¹ phosphorylation of PKCδ in HeLa cells. In RBL-2H3 cells, RJ and BGPP also suppressed NFAT-mediated IL-9 gene expression. These results suggest that RJ and BGPP improve allergic symptoms by suppressing PKCδ and NFAT signaling pathways, two important signal pathways for the AR pathogenesis, and suggest that RJ and BGPP could be good therapeutics against AR.

Altered levels of memory T cell subsets and common γc cytokines in Strongyloides stercoralis infection and partial reversal following anthelmintic treatment

BACKGROUND

CD4+ and CD8+ T cells are central players in immunity to helminth infections. However, the role of T cell subsets in human helminth infections is not well understood. In addition, the common γc cytokines, IL-2, IL-4, IL-7, IL-9 and IL-15 play an important role in the maintenance of these CD4+ and CD8+ T cell subsets.

METHODS

To examine the major T cell subsets and their association with the common γc cytokines, the absolute numbers of CD4+ and CD8+ naïve, central memory, effector memory and effector cells and the plasma levels of IL-2, IL-4, IL-7, IL-9 and IL-15 were measured in Strongyloides stercoralis (Ss) infected (INF, n = 60), helminth-uninfected (UN, n = 58) and in post treatment INF individuals.

RESULTS

Ss infection is characterized by significantly increased absolute numbers of naïve and decreased absolute numbers of central and effector memory CD4+ T cells in comparison to UN individuals. No significant difference in the numbers of CD8+ T cell subsets was observed between the groups. The numbers of naïve cells and central memory CD4+ T cells were significantly reversed after anthelmintic treatment. Circulating levels of IL-2, IL-7 and IL-15 were significantly diminished, whereas the levels of IL-4 and IL-9 were significantly increased in INF compared to UN individuals. Following anthelminthic treatment, IL-2, IL-7 and IL-15 levels were significantly increased, while IL-4 and IL-9 levels were significantly decreased. Our data also showed a significant positive correlation between the levels of IL-7 and the numbers of central and effector memory CD4+ T cells.

CONCLUSION

Ss infection is characterized by alterations in the absolute numbers of CD4+ T cell subsets and altered levels of common γc cytokines IL-2, IL-4, IL-7, IL-9 and IL-15; alterations which are partially reversed after anthelmintic treatment.

Striking the right immunological balance prevents progression of tuberculosis

INTRODUCTION

Tuberculosis (TB) caused by infection with Mycobacterium tuberculosis (Mtb) is a major burden for human health worldwide. Current standard treatments for TB require prolonged administration of antimycobacterial drugs leading to exaggerated inflammation and tissue damage. This can result in the reactivation of latent TB culminating in TB progression. Thus, there is an unmet need to develop therapies that would shorten the duration of anti-TB treatment and to induce optimal protective immune responses to control the spread of mycobacterial infection with minimal lung pathology.

FINDINGS

Granulomata is the hallmark structure formed by the organized accumulation of immune cells including macrophages, natural killer cells, dendritic cells, neutrophils, T cells, and B cells to the site of Mtb infection. It safeguards the host by containing Mtb in latent form. However, granulomata can undergo caseation and contribute to the reactivation of latent TB, if the immune responses developed to fight mycobacterial infection are not properly controlled. Thus, an optimal balance between innate and adaptive immune cells might play a vital role in containing mycobacteria in latent form for prolonged periods and prevent the spread of Mtb infection from one individual to another.

CONCLUSION

Optimal and well-regulated immune responses against Mycobacterium tuberculosis may help to prevent the reactivation of latent TB. Moreover, therapies targeting balanced immune responses could help to improve treatment outcomes among latently infected TB patients and thereby limit the dissemination of mycobacterial infection.

Immune Regulation of Toll-Like Receptor 2 Engagement on CD4+ T Cells in Murine Models of Malignant Pleural Effusion

Toll-like receptor (TLR) 2 has a well-known role in sensing multiple ligands that include microbial products, endotoxin, and some extracellular matrix molecules; however, its role in the development of malignant pleural effusion (MPE) remains unknown. We performed the present study to explore the impact of TLR2 signaling on the development of MPE and to define the underlying mechanisms by which TLR2 works. Development of MPE was compared between TLR2^-/- and wild-type (WT) mice. The effect of TLR2 on differentiation of T helper type 17 (Th17), Th9, and Th2 cells in MPE was explored. The mechanisms of TLR2 on survival of mice bearing MPE were also investigated. MPE volume in TLR2^-/- mice was lower than that in WT mice, and the survival of TLR2^-/- mice bearing MPE was longer than that of WT mice. TLR2 deficiency increased, and TLR2 activation decreased, Th17 cells in MPE, whereas TLR2 signaling showed the contrary effects on Th2 cells. Th9 cells were increased in MPE of TLR2^-/- mice but were not influenced by TLR2 signaling. Intraperitoneal injection of anti-IL-17 monoclonal antibody (mAb), anti-IL-9 mAb, or recombinant mouse IL-4 accelerated the death of TLR2^-/- mice bearing MPE, and intraperitoneal injection anti-IL-17 mAb in TLR2^-/- mice was associated with a significantly shorter survival time than in WT mice. We have demonstrated, for the first time, that TLR2 signaling promotes the development of MPE and accelerates the death of mice bearing MPE by directly suppressing Th17 cell differentiation and directly promoting Th2 cell differentiation, and also by indirectly suppressing Th9 cell differentiation via an IL-17-dependent mechanism.

Interleukin-9 Promotes TNF-α and PGE2 Release in Human Degenerated Intervertebral Disc Tissues

STUDY DESIGN

Based on human disc surgical samples and isolated cells in vitro, we undertook a descriptive and mechanistic investigation of proinflammatory effects of interleukin (IL)-9 in intervertebral disc (IVD) degeneration.

OBJECTIVE

To investigate the proinflammatory role of IL-9 in the pathological process of IVD degeneration.

SUMMARY OF BACKGROUND DATA

IL-9 is known as a pleiotropic cytokine that regulates the human pathogenesis of inflammatory and autoimmune diseases. However, whether IL-9 cytokine is involved in the immuno-inflammatory pathogenesis of IVD degeneration is unclear.

METHODS

The IVD samples were obtained from 45 patients. Immunohistochemistry, western blot, and real-time Polymerase Chain Reaction (PCR) were performed to detect the expression of IL-9 and tumor necrosis factor alpha (TNF-α) in the degenerated IVDs. Moreover, nucleus pulposus (NP) cells were treated with 0, 1, 10, and 100 ng/mL IL-9 cytokine and stimulated with IL-9 alone at 100 ng/mL for 0, 12, 24, and 48 hours. TNF-α expression was determined by immunofluorescence staining, western blot, and real-time PCR, respectively. The amounts of TNF-α and prostaglandin E2 (PGE2) in the supernatant were quantified by enzyme-linked immunosorbent assay. Additionally, Spearman correlation analyses were performed to analyze the correlation between Pfirrmann grading score of the involved degenerated IVDs and serum levels of IL-9.

RESULTS

The expressions of IL-9 and TNF-α in degenerated IVD tissues were dramatically elevated in comparison with the control. IL-9 significantly up-regulated the TNF-α and PGE2 secretion of NP cells in dose- and time-dependent manner. Moreover, there is a positive correlation between IL-9 serum level and severity of involved IVD degeneration.

CONCLUSION

Our findings suggest that IL-9 may play a potential role in the inflammatory processes of IVD degeneration. IL-9 may be involved in the IVD degeneration, at least in part, though stimulating the release of TNF-α and PGE2 in NP cells.

LEVEL OF EVIDENCE

N/A.

A novel cell-penetrating peptide suppresses breast tumorigenesis by inhibiting β-catenin/LEF-1 signaling

The inhibition of β-catenin/LEF-1 signaling is an emerging strategy in cancer therapy. However, clinical targeted treatment of the β-catenin/LEF-1 complex remains relatively ineffective. Therefore, development of specific molecular targets is a key approach for identifying new cancer therapeutics. Thus, we attempted to synthesize a peptide (TAT-NLS-BLBD-6) that could interfere with the interaction of β-catenin and LEF-1 at nuclei in human breast cancer cells. TAT-NLS-BLBD-6 directly interacted with β-catenin and inhibited breast cancer cell growth, invasion, migration, and colony formation as well as increased arrest of sub-G1 phase and apoptosis; it also suppressed breast tumor growth in nude mouse and zebrafish xenotransplantation models, showed no signs of toxicity, and did not affect body weight. Furthermore, the human global gene expression profiles and Ingenuity Pathway Analysis software showed that the TAT-NLS-BLBD-6 downstream target genes were associated with the HER-2 and IL-9 signaling pathways. TAT-NLS-BLBD-6 commonly down-regulated 27 candidate genes in MCF-7 and MDA-MB-231 cells, which are concurrent with Wnt downstream target genes in human breast cancer. Our study suggests that TAT-NLS-BLBD-6 is a promising drug candidate for the development of effective therapeutics specific for Wnt/β-catenin signaling inhibition.

Suplatast tosilate alleviates nasal symptoms through the suppression of nuclear factor of activated T-cells-mediated IL-9 gene expression in toluene-2,4-diisocyanate-sensitized rats

Histamine H1 receptor (H1R) gene is upregulated in patients with pollinosis; its expression level is highly correlated with the nasal symptom severity. Antihistamines are widely used as allergy treatments because they inhibit histamine signaling by blocking H1R or suppressing H1R signaling as inverse agonists. However, long-term treatment with antihistamines does not completely resolve toluene-2,4-diisocyanate (TDI)-induced nasal symptoms, although it can decrease H1R gene expression to the basal level, suggesting additional signaling is responsible for the pathogenesis of the allergic symptoms. Here, we show that treatment with suplatast tosilate in combination with antihistamines markedly alleviates nasal symptoms in TDI-sensitized rats. Suplatast suppressed TDI-induced upregulation of IL-9 gene expression. Suplatast also suppressed ionomycin/phorbol-12-myristate-13-acetate-induced upregulation of IL-2 gene expression in Jurkat cells, in which calcineurin (CN)/nuclear factor of activated T-cells (NFAT) signaling is known to be involved. Immunoblot analysis demonstrated that suplatast inhibited binding of NFAT to DNA. Furthermore, suplatast suppressed ionomycin-induced IL-9 mRNA upregulation in RBL-2H3 cells, in which CN/NFAT signaling is also involved. These data suggest that suplatast suppressed NFAT-mediated IL-9 gene expression in TDI-sensitized rats and this might be the underlying mechanism of the therapeutic effects of combined therapy of suplatast with antihistamine.

Inhibition of G-Protein βγ Signaling Decreases Levels of Messenger RNAs Encoding Proinflammatory Cytokines in T Cell Receptor-Stimulated CD4(+) T Helper Cells

Background: Inhibition of G-protein βγ (Gβγ) signaling was found previously to enhance T cell receptor (TCR)-stimulated increases in interleukin 2 (IL-2) mRNA in CD4⁺ T helper cells, suggesting that Gβγ might be a useful drug target for treating autoimmune diseases, as low dose IL-2 therapy can suppress autoimmune responses. Because IL-2 may counteract autoimmunity in part by shifting CD4⁺ T helper cells away from the Type 1 T helper cell (TH1) and TH17 subtypes towards the TH2 subtype, the purpose of this study was to determine if blocking Gβγ signaling affected the balance of TH1, TH17, and TH2 cytokine mRNAs produced by CD4⁺ T helper cells.

Methods: Gallein, a small molecule inhibitor of Gβγ, and siRNA-mediated silencing of the G-protein β₁ subunit (Gβ₁) were used to test the effect of blocking Gβγ on mRNA levels of cytokines in primary human TCR-stimulated CD4⁺ T helper cells.

Results: Gallein and Gβ₁ siRNA decreased interferon-γ (IFN-γ) and IL-17A mRNA levels in TCR-stimulated CD4⁺ T cells grown under TH1-promoting conditions. Inhibiting Gβγ also decreased mRNA levels of STAT4, which plays a positive role in TH1 differentiation and IL-17A production. Moreover, mRNA levels of the STAT4-regulated TH1-associated proteins, IL-18 receptor β chain (IL-18Rβ), mitogen-activated protein kinase kinase kinase 8 (MAP3K8), lymphocyte activation gene 3 (LAG-3), natural killer cell group 7 sequence (NKG7), and oncostatin M (OSM) were also decreased upon Gβγ inhibition. Gallein also increased IL-4, IL-5, IL-9, and IL-13 mRNA levels in TCR-stimulated memory CD4⁺ T cells grown in TH2-promoting conditions.

Conclusions: Inhibiting Gβγ to produce these shifts in cytokine mRNA production might be beneficial for patients with autoimmune diseases such as rheumatoid arthritis (RA), Crohn’s disease (CD), psoriasis, multiple sclerosis (MS), and Hashimoto’s thyroiditis (HT), in which both IFN-γ and IL-17A are elevated.

The TNF-family ligand TL1A and its receptor DR3 promote T cell-mediated allergic immunopathology by enhancing differentiation and pathogenicity of IL-9-producing T cells

The TNF family cytokine TL1A (Tnfsf15) costimulates T cells and type 2 innate lymphocytes (ILC2) through its receptor DR3 (Tnfrsf25). DR3-deficient mice have reduced T cell accumulation at the site of inflammation and reduced ILC2-dependent immune responses in a number of models of autoimmune and allergic diseases. In allergic lung disease models, immunopathology and local Th2 and ILC2 accumulation is reduced in DR3-deficient mice despite normal systemic priming of Th2 responses and generation of T cells secreting IL-13 and IL-4, prompting the question of whether TL1A promotes the development of other T cell subsets that secrete cytokines to drive allergic disease. In this study, we find that TL1A potently promotes generation of murine T cells producing IL-9 (Th9) by signaling through DR3 in a cell-intrinsic manner. TL1A enhances Th9 differentiation through an IL-2 and STAT5-dependent mechanism, unlike the TNF-family member OX40, which promotes Th9 through IL-4 and STAT6. Th9 differentiated in the presence of TL1A are more pathogenic, and endogenous TL1A signaling through DR3 on T cells is required for maximal pathology and IL-9 production in allergic lung inflammation. Taken together, these data identify TL1A-DR3 interactions as a novel pathway that promotes Th9 differentiation and pathogenicity. TL1A may be a potential therapeutic target in diseases dependent on IL-9.

Subpopulations of helper T lymphocytes in tuberculous pleurisy

Although it is curable, tuberculosis continues to be is a major global public health problem, especially in developing countries. Tuberculous pleural effusion (TPE) is one of the most common forms of extrapulmonary tuberculosis. It has been well documented that CD4(+) T lymphocytes are dominant leukocytes present in TPE. Traditionally, CD4(+) T cells have been classified into two functionally distinct subsets, helper T-cell type 1 (Th1) and Th2 cells, based on their cytokine production profiles. Recently, regulatory T cells, Th17 cells, Th9 cells, and Th22 cells have been added to the 'portfolio' of Th cells. In this review, we summarize recent findings regarding the phenotypic characteristics of the above Th cells, the mechanisms of differentiation and recruitment of Th cells into pleural space, and the immune regulation of Th cells in TPE environment. We also describe the interplay between different Th cells, as well as between Th cells and other type of cells, such as pleural mesothelial cells in TPE. Further studies should be directed at identifying the mediators and mechanisms involved in the immunoregulatory properties of pleural Th cells in tuberculosis infection.

Involvement of IL-9 in Th17-associated inflammation and angiogenesis of psoriasis

It is thought that a Th1/Th17-weighted immune response plays a predominant role in the pathogenesis of psoriasis. Our findings now indicate a link between IL-9, a Th2 and Th9 cytokine, and Th17 pathway in psoriasis. In K5.hTGF-β1 transgenic mice, exhibiting a psoriasis-like phenotype, we found increased IL-9R and IL-9 expression in the skin and intradermal IL-9 injection induced Th17-related inflammation. IL-9 also promoted angiogenesis and VEGF and CD31 overexpression in mice in vivo and increased tube formation of human endothelial cells in vitro. Injecting anti-IL-9 antibody into K5.hTGF-β1 transgenic mice not only diminished inflammation (including skin infiltration by T cells, monocytes/macrophages, and mast cells) and angiogenesis but also delayed the psoriasis-like skin phenotype. Notably, injection of anti-psoriatic acting anti-IL-17 antibody reduced skin IL-9 mRNA and serum IL-9 protein levels in K5.hTGF-β1 transgenic mice and prevented IL-9-induced epidermal hyperplasia and inflammation of the skin of wild type mice. In addition, we observed that IL-9R expression in lesional skin from psoriasis patients was markedly higher than in healthy skin from control subjects. Moreover, IL-9 significantly enhanced IL-17A production by cultured human peripheral blood mononuclear cells or CD4+ T cells, especially in psoriasis patients. Thus, IL-9 may play a role in the development of psoriatic lesions through Th17-associated inflammation and angiogenesis.

Do mast cells link obesity and asthma?

Asthma is a chronic inflammatory disease of the lungs. Both the number of cases and severity of asthma have been increasing without a clear explanation. Recent evidence suggests that obesity, which has also been increasing alarmingly, may worsen or precipitate asthma, but there is little evidence of how obesity may contribute to lung inflammation. We propose that mast cells are involved in both asthma and obesity by being the target and source of adipocytokines, 'alarmins' such as interleukin-9 (IL-9) and interleukin-33 (IL-33), and stress molecules including corticotropin-releasing hormone (CRH) and neurotensin (NT), secreted in response to the metabolic burden. In particular, CRH and NT have synergistic effects on mast cell secretion of vascular endothelial growth factor (VEGF). IL-33 augments VEGF release induced by substance P (SP) and tumor necrosis factor (TNF) release induced by NT. Both IL-9 and IL-33 also promote lung mast cell infiltration and augment allergic inflammation. These molecules are also expressed in human mast cells leading to autocrine effects. Obese patients are also less sensitive to glucocorticoids and bronchodilators. Development of effective mast cell inhibitors may be a novel approach for the management of both asthma and obesity. Certain flavonoid combinations may be a promising new treatment approach.

Programmed cell death ligand 2 regulates TH9 differentiation and induction of chronic airway hyperreactivity

BACKGROUND

Asthma is defined as a chronic inflammatory disease of the airways; however, the underlying physiologic and immunologic processes are not fully understood.

OBJECTIVE

The aim of this study was to determine whether TH9 cells develop in vivo in a model of chronic airway hyperreactivity (AHR) and what factors control this development.

METHOD

We have developed a novel chronic allergen exposure model using the clinically relevant antigen Aspergillus fumigatus to determine the time kinetics of TH9 development in vivo.

RESULTS

TH9 cells were detectable in the lungs after chronic allergen exposure. The number of TH9 cells directly correlated with the severity of AHR, and anti-IL-9 treatment decreased airway inflammation. Moreover, we have identified programmed cell death ligand (PD-L) 2 as a negative regulator of TH9 cell differentiation. Lack of PD-L2 was associated with significantly increased TGF-β and IL-1α levels in the lungs, enhanced pulmonary TH9 differentiation, and higher morbidity in the sensitized mice.

CONCLUSION

Our findings suggest that PD-L2 plays a pivotal role in the regulation of TH9 cell development in chronic AHR, providing novel strategies for modulating adaptive immunity during chronic allergic responses.

Pathophysiology, favoring factors, and associated disorders in otorhinosinusology

The pathogenesis of rhinosinusitis (RS) is related to inflammation, caused by infections in the acute form of the disease but also by other agents in the chronic forms. Cytology allows to evaluate the defensive components, such as hair cells and muciparous cells, while the presence in the nasal mucosa of eosinophils, mast cells, bacteria and/or fungal hyphae, or spores indicates the nasal pathology. The anatomic and physiologic characteristics of the otorhinosinusal system account for the frequent concomitant involvement of the different components. The pivotal pathophysiologic sites are the ostiomeatal complex, the spheno-ethmoidal recess, and the Eustachian tube. The latter is the link with acute otitis media (AOM), which is the most common disease in infants and children and has major medical, social, and economic effects. Moreover, because of the strict relationship between upper and lower airways, nasal sinus disease may contribute to asthma and sinusitis may be considered as an independent factor associated with frequent severe asthma exacerbations. Concerning the role of allergy, the available data do not permit to attribute a central role to atopy in sinusitis and thus allergy testing should not be a routine procedure, while an allergologic evaluation may be indicated in children with OM, especially when they have concomitant rhinitis.

Nuclear factor of activated T cells 1 (NFAT1)-induced permissive chromatin modification facilitates nuclear factor-κB (NF-κB)-mediated interleukin-9 (IL-9) transactivation

IL-9 regulates diverse inflammatory immune responses. Although the functional importance of IL-9 has been investigated in various pathophysiological conditions, molecular mechanisms by which TCR stimulation induced IL-9 gene expression are still unclear. In this study, we investigated the functional importance of the NFAT1 and NF-κB (p65) in IL-9 gene transcription in CD4(+) T cells. In vivo binding of NFAT1 and NF-κB (p65) to the IL-9 promoter was observed. NFAT1 binding induced a transcriptionally active chromatin configuration at the IL-9 promoter locus, whereas NF-κB (p65) binding transactivated the IL-9 promoter. Mouse deficient in NFAT1 shows a significant down-regulation of IL-9 expression that resulted from an inaccessible chromatin configuration at the IL-9 promoter. In parallel, knockdown of NF-κB (p65) also resulted in reduced IL-9 expression. In this process, NFAT1 plays a pivotal role as a core protein that creates an accessible platform for the assembly of transcription activators. The presence of NFAT1 correlates with recruitment of NF-κB (p65), p300, and active histone markers on the IL-9 promoter, resulting in a transcriptionally competent promoter. NFAT1 deficiency significantly reduced the recruitment of the above activation complex to the IL-9 promoter. In summary, our data suggest that functional cooperation of NFAT1 and NF-κB synergistically enhances IL-9 transcription in CD4(+) T cells.

Differentiation and recruitment of Th9 cells stimulated by pleural mesothelial cells in human Mycobacterium tuberculosis infection

Newly discovered IL-9–producing CD4⁺ helper T cells (Th9 cells) have been reported to contribute to tissue inflammation and immune responses, however, differentiation and immune regulation of Th9 cells in tuberculosis remain unknown. In the present study, our data showed that increased Th9 cells with the phenotype of effector memory cells were found to be in tuberculous pleural effusion as compared with blood. TGF-β was essential for Th9 cell differentiation from naïve CD4⁺ T cells stimulated with PMA and ionomycin in vitro for 5 h, and addition of IL-1β, IL-4 or IL-6 further augmented Th9 cell differentiation. Tuberculous pleural effusion and supernatants of cultured pleural mesothelial cells were chemotactic for Th9 cells, and this activity was partly blocked by anti-CCL20 antibody. IL-9 promoted the pleural mesothelial cell repairing and inhibited IFN-γ-induced pleural mesothelial cell apoptosis. Moreover, pleural mesothelial cells promoted Th9 cell differentiation by presenting antigen. Collectively, these data provide new information concerning Th9 cells, in particular the collaborative immune regulation between Th9 cells and pleural mesothelial cells in human M. tuberculosis infection. In particular, pleural mesothelial cells were able to function as antigen-presenting cells to stimulate Th9 cell differentiation.

Soybean isoflavones regulate dendritic cell function and suppress allergic sensitization to peanut

BACKGROUND

Although peanut and soybean proteins share extensive amino acid sequence homology, the incidence and severity of allergic reactions to soy are much less than those to peanut. Soybeans are rich in anti-inflammatory isoflavones and are the most common source of isoflavones in the human food supply.

OBJECTIVE

We hypothesized that the active isoflavones in the gut milieu are capable of modulating immune responses to dietary antigens by regulating dendritic cell (DC) function.

METHODS

We tested this hypothesis in a murine model of peanut allergy and in human monocyte-derived dendritic cells (MDDCs). C3H/HeJ mice were fed a diet containing genistein and daidzein. The mice were sensitized and challenged with peanut, and the anaphylactic symptoms were compared with those of mice fed a soy-free diet. Human MDDCs were activated with cholera toxin in the presence of isoflavones. The surface expression of DC activation markers and DC-mediated effector functions were analyzed by means of flow cytometry.

RESULTS

Dietary isoflavones significantly reduced the anaphylactic symptoms and mast cell degranulation in vivo after peanut challenge. Serum peanut-specific antibodies were markedly reduced in mice fed the isoflavone diet. Isoflavones inhibited cholera toxin-induced DC maturation in the mesenteric lymph nodes and human MDDCs and subsequent DC-mediated CD4(+) T-cell function in vitro.

CONCLUSIONS

These data suggest that dietary isoflavones suppress allergic sensitization and protect against peanut allergy in vivo. Dietary supplementation of soybean isoflavones could be a novel strategy to prevent the development of allergic reactions to food.

IL-9(+) IL-10(+) T cells link immediate allergic response to late phase reaction

The mechanism underlying late-phase allergic reactions (LPR) remains incompletely understood. This study aimed to investigate the role of a newly described subset of T cells, interleukin (IL)-9(+) IL-10(+) T cells, in the pathogenesis of LPR. Using a T helper type 2 (Th2) inflammatory mouse model, we examined the frequency of IL-9(+) IL-10(+) T cells in the jejunum by immunohistochemistry. The LPR in the jejunum was observed afterwards. The cytokine profile of IL-9(+) IL-10(+) T cells was characterized and the major cytokine that plays the critical role in the initiation of LPR was investigated. Abundant IL-9(+) IL-10(+) T cells as well as inflammatory cell extravasation in the jejunal sections were observed in sensitized mice 48 h after specific antigen challenge. IL-9(+) IL-10(+) T cells expressed high levels of macrophage inflammatory protein 1 (MIP1) that could be enhanced by T cell receptor activation. MIP1 facilitated macrophage extravasation in local tissue. Macrophage-derived MIP2 contributed to neutrophil infiltration in the intestine in LPR. Pretreatment with anti-MIP antibody inhibited the LPR in the intestine. IL-9(+) IL-10(+) T cells play an important role in LPR. This subset of T cells has the potential to be a novel therapeutic target in the treatment of LPR and LPR-related inflammation.

Safety profile and clinical activity of multiple subcutaneous doses of MEDI-528, a humanized anti-interleukin-9 monoclonal antibody, in two randomized phase 2a studies in subjects with asthma

Background

Interleukin-9 (IL-9)-targeted therapies may offer a novel approach for treating asthmatics. Two randomized placebo-controlled studies were conducted to assess the safety profile and potential efficacy of multiple subcutaneous doses of MEDI-528, a humanized anti-IL-9 monoclonal antibody, in asthmatics.

Methods

Study 1: adults (18-65 years) with mild asthma received MEDI-528 (0.3, 1, 3 mg/kg) or placebo subcutaneously twice weekly for 4 weeks. Study 2: adults (18-50 years) with stable, mild to moderate asthma and exercise-induced bronchoconstriction received 50 mg MEDI-528 or placebo subcutaneously twice weekly for 4 weeks. Adverse events (AEs), pharmacokinetics (PK), immunogenicity, asthma control (including asthma exacerbations), and exercise challenge test were evaluated in study 1, study 2, or both.

Results

In study 1 (N = 36), MEDI-528 showed linear serum PK; no anti-MEDI-528 antibodies were detected. Asthma control: 1/27 MEDI-528-treated subjects had 1 asthma exacerbation, and 2/9 placebo-treated subjects had a total of 4 asthma exacerbations (one considered a serious AE). In study 2, MEDI-528 (n = 7) elicited a trend in the reduction in mean maximum decrease in FEV₁ post-exercise compared to placebo (n = 2) (-6.49% MEDI-528 vs -12.60% placebo; -1.40% vs -20.10%; -5.04% vs -15.20% at study days 28, 56, and 150, respectively). Study 2 was halted prematurely due to a serious AE in an asymptomatic MEDI-528-treated subject who had an abnormal brain magnetic resonance imaging that was found to be an artifact on further evaluation.

Conclusions

In these studies, MEDI-528 showed an acceptable safety profile and findings suggestive of clinical activity that support continued study in subjects with mild to moderate asthma.

Trial registration

ClinicalTrials (NCT): NCT00507130 and ClinicalTrials (NCT): NCT00590720

Th9: a new player in asthma pathogenesis?

CD4(+) T helper (Th) cells act as important regulators of the mammalian adaptive immune response. CD4(+) Th cells were originally characterized as either Th1 or Th2 types, based on the cytokines they produce. Over the past two decades, however, we have attained a much more detailed understanding of CD4(+) T-cell differentiation, functions, and gene expression profiles, which led to the identification of additional types, such as the Th17 and induced regulatory T cells. Recently, researchers have characterized yet another novel and distinct population that exists among these immune-modulatory cells. The 'Th9' cells were first identified as a Th2 subpopulation that produced exceptionally large quantities of the Th2-specific cytokine interleukin 9. However, experimental analysis revealed that Th9 cells had divergent regulatory capabilities and were critically involved in different immune processes. In particular, we now know that Th9 acts as a major contributor to the onset and progression of allergies, especially asthma. Here, we will review the heterogeneity and biology of CD4(+) Th cells and summarize the characteristics known to date of interleukin 9 and Th9 cells to build a framework for better understanding of their roles in disease processes, especially in allergy-induced asthma.

IL-9 production by regulatory T cells recruits mast cells that are essential for regulatory T cell-induced immune suppression

Both mast cells (MCs) and regulatory T cells (Tregs) have gained attention as immunosuppressive cell populations. To investigate a possible interaction, we used the Th1- and Th17-dependent model of nephrotoxic serum nephritis (NTS), in which both MCs and Tregs have been shown to play a protective role. Transfer of wild-type (wt) Tregs into wt recipients almost completely prevents development of NTS and leads to a profound increase of MCs in the renal draining lymph nodes (LNs). By contrast, transfer of wt Tregs into animals deficient in MCs, which are characterized by an exaggerated susceptibility to NTS, no longer exhibited protective effects. Blocking the pleiotropic cytokine IL-9, known to be involved in MC recruitment and proliferation, by means of a mAb in mice receiving Tregs abrogated protection from NTS. Moreover, transfer of IL-9-deficient Tregs also failed to protect from NTS. In the absence of Treg-derived IL-9, MCs fail to accumulate in the LNs, despite the fact that IL-9 deficiency does not alter the general suppressive activity of Tregs. In summary, to our knowledge, we provide the first direct in vivo evidence that the nephroprotective, anti-inflammatory effects of Tregs critically depend on IL-9-mediated attraction of MCs into kidney-draining LNs.

Eosinophils in innate immunity: an evolving story

Eosinophils are innate immune leukocytes found in relatively low numbers within the blood. Terminal effector functions of eosinophils, deriving from their capacity to release their content of tissue-destructive cationic proteins, have historically been considered primary effector mechanisms against specific parasites, and are likewise implicated in tissue damage accompanying allergic responses such as asthma. However, the past decade has seen dramatic advancements in the field of eosinophil immunobiology, revealing eosinophils to also be key participants in many other facets of innate immunity, from bridging innate and adaptive immune responses to orchestrating tissue remodeling events. Here, we review the multifaceted functions of eosinophils in innate immunity that are currently known, and discuss new avenues in this evolving story.

TGF-beta induces IL-9 production from human Th17 cells

The secretion of IL-9, initially recognized as a Th2 cytokine, was recently attributed to a novel CD4 T cell subset termed Th9 in the murine system. However, IL-9 can also be secreted by mouse Th17 cells and may mediate aspects of the proinflammatory activities of Th17 cells. Here we report that IL-9 is secreted by human naive CD4 T cells in response to differentiation by Th9 (TGF-beta and IL-4) or Th17 polarizing conditions. Yet, these differentiated naive cells did not coexpress IL-17 and IL-9, unless they were repeatedly stimulated under Th17 differentiation-inducing conditions. In contrast to the naive cells, memory CD4 T cells were induced to secrete IL-9 by simply providing TGF-beta during stimulation, as neither IL-4 nor proinflammatory cytokines were required. Furthermore, the addition of TGF-beta to the Th17-inducing cytokines (IL-1beta, IL-6, IL-21, IL-23) that induce memory cells to secrete IL-17, resulted in the marked coexpression of IL-9 in IL-17 producing memory cells. The proinflammatory cytokine mediating TGF-beta-dependent coexpression of IL-9 and IL-17 was identified to be IL-1beta. Moreover, circulating monocytes were potent costimulators of IL-9 production by Th17 cells via their capacity to secrete IL-1beta. Finally, to determine whether IL-9/IL-17 coproducing CD4 cells were altered in an inflammatory condition, we examined patients with autoimmune diabetes and demonstrated that these subjects exhibit a higher frequency of memory CD4 cells with the capacity to transition into IL-9(+)IL-17(+) cells. These data demonstrate the presence of IL-17(+)IL-9(+) CD4 cells induced by IL-1beta that may play a role in human autoimmune disease.

The transcription factor PU.1 is required for the development of IL-9-producing T cells and allergic inflammation

CD4⁺ T helper cells acquire effector phenotypes that promote specialized inflammatory responses. We show that the ETS family transcription factor, PU.1 was required for the development of an interleukin 9 (IL-9)-secreting subset of T_H cells. Decreasing PU.1 expression either by conditional deletion in murine T cells or siRNA in human T cells impaired IL-9 production, while ectopic PU.1 expression promoted IL-9 production. Mice with PU.1-deficient T cells developed normal T_H2 responses in vivo, but exhibited attenuated allergic pulmonary inflammation corresponding to decreased Il9 and chemokine expression in peripheral T cells and in lungs as compared to wild-type mice. Together, these data suggest a critical role for PU.1 in generating the T_H9 phenotype and in the development of allergic inflammation.

Differential roles for the IL-9/IL-9 receptor alpha-chain pathway in systemic and oral antigen-induced anaphylaxis

BACKGROUND

The cytokine IL-9 has been implicated in allergic reactions, including food allergy, but its contribution to parenteral versus oral antigen-induced anaphylaxis remains unclear.

OBJECTIVES

We sought to delineate the contribution of the IL-9/IL-9 receptor alpha-chain (IL-9R) pathway to parenteral and oral antigen-induced anaphylaxis.

METHODS

Wild-type, IL-9-deficient (Il9(-/-)), and IL-9R-deficient (Il9R(-/-)) mice were subjected to passive and active parenteral and oral antigen (ovalbumin [OVA])-induced anaphylaxis. Severity of systemic anaphylaxis was gauged by decreased body temperature; intestinal anaphylaxis was assessed based on secretory diarrhea, intestinal mastocytosis, and serum murine mast cell protease 1 level. Specific immunoglobulin isotypes or immunoglobulin receptor-blocking antibodies were administered before challenge to define the role of the IgE and IgG pathways.

RESULTS

Repeated oral antigen challenge of OVA-sensitized wild-type mice induced anaphylaxis with both systemic and intestinal involvement; both were IgE dependent and attenuated in Il9(-/-) and Il9R(-/-) mice. In contrast, parenteral OVA challenge of OVA-sensitized wild-type mice induced systemic anaphylaxis, which was independent of the IL-9/IL-9R pathway. Strikingly, the IL-9/IL-9R pathway had no role in either the IgG or IgE component of parenteral antigen-induced or anti-IgE and anti-FcgammaRII/III mAb-induced systemic anaphylaxis.

CONCLUSIONS

Parenteral antigen-induced murine systemic anaphylaxis is mediated by both IgG- and IgE-dependent pathways, and both can occur independently of IL-9/IL-9R signaling. In contrast, oral antigen-induced intestinal and systemic anaphylaxis is strictly IgE mediated and requires IL-9/IL-9R signaling. These studies indicate differential involvement of the IL-9/IL-9R pathway in systemic and oral antigen-induced anaphylaxis.

The postnatal maternal environment affects autoimmune disease susceptibility in A/J mice

The postnatal maternal environment is known to increase susceptibility to a number of autoimmune diseases. Here we asked whether the postnatal maternal environment could influence autoimmune disease development to day 3 thymectomy (d3tx)-induced autoimmune ovarian disease (AOD) and experimental allergic encephalomyelitis (EAE) in cross-fostered A/J and B6 mice. A/J pups foster-nursed by B6 mothers exhibit an increase in autoimmune disease development while cross-fostering B6 pups on A/J mothers did not alter their susceptibility. The increase in AOD incidence seen in foster-nursed d3tx A/J mice correlated with a decrease in the total number of CD4(+) T cells in the lymph nodes of these animals. Analysis of the cellular composition in the milk revealed that B6 mice shed significantly more maternally derived lymphocytes into their milk compared to A/J mothers. These data suggest that there are maternally derived postnatal factors that influence the development of autoimmune disease in A/J mice.

Th9 and allergic disease

Helper CD4(+) T-cell subsets have improved our understanding of adaptive immunity in humans and in animal models of disease. These include T helper type 1 (Th1), Th2 and the interleukin-17 (IL-17) -producing population 'Th17'. Th2 cells have been described as orchestrating the immune response in allergic disease based on studies with patient samples and animal models. The cytokine IL-9 has largely been regarded as a Th2 cytokine that makes multifocal contributions to allergic disease. Recent data suggest that under certain conditions relevant to chronic disease (IL-4 and transforming growth factor-beta), a distinct population of IL-9-producing 'Th9' helper T cells can exist. The contribution of Th9 cells in allergic disease is currently unknown, and this review will propose a model for how these cells may regulate chronic allergic inflammation.

New insights into the regulation of T cells by gamma(c) family cytokines

Common cytokine receptor gamma-chain (gamma(c)) family cytokines have crucial roles in the development, proliferation, survival and differentiation of multiple cell lineages of both the innate and adaptive immune systems. In this Review, we focus on our current understanding of the distinct and overlapping effects of interleukin-2 (IL-2), IL-7, IL-9, IL-15 and IL-21, as well as the IL-7-related cytokine thymic stromal lymphopoietin (TSLP), on the survival and proliferation of conventional alphabeta T cells, gammadelta T cells and regulatory T cells. This knowledge potentially allows for the therapeutic manipulation of immune responses for the treatment of cancer, autoimmunity, allergic diseases and immunodeficiency, as well as for vaccine development.

IL-9 as a mediator of Th17-driven inflammatory disease

We report that like other T cells cultured in the presence of transforming growth factor (TGF) beta, Th17 cells also produce interleukin (IL) 9. Th17 cells generated in vitro with IL-6 and TGF-beta as well as purified ex vivo Th17 cells both produced IL-9. To determine if IL-9 has functional consequences in Th17-mediated inflammatory disease, we evaluated the role of IL-9 in the development and progression of experimental autoimmune encephalomyelitis, a mouse model of multiple sclerosis. The data show that IL-9 neutralization and IL-9 receptor deficiency attenuates disease, and this correlates with decreases in Th17 cells and IL-6-producing macrophages in the central nervous system, as well as mast cell numbers in the regional lymph nodes. Collectively, these data implicate IL-9 as a Th17-derived cytokine that can contribute to inflammatory disease.

Pulmonary fibrosis: pathogenesis, etiology and regulation

Pulmonary fibrosis and architectural remodeling of tissues can severely disrupt lung function, often with fatal consequences. The etiology of pulmonary fibrotic diseases is varied, with an array of triggers including allergens, chemicals, radiation and environmental particles. However, the cause of one of the most common pulmonary fibrotic conditions, idiopathic pulmonary fibrosis (IPF), is still unclear. This review examines common mechanisms of pulmonary wound-healing responses following lung injury, and highlights the pathogenesis of some of the most widespread pulmonary fibrotic diseases. A three phase model of wound repair is reviewed that includes; (1) injury; (2) inflammation; and (3) repair. In most pulmonary fibrotic conditions dysregulation at one or more of these phases has been reported. Chronic inflammation can lead to an imbalance in the production of chemokines, cytokines, growth factors, and disrupt cellular recruitment. These changes coupled with excessive pro-fibrotic IL-13 and/or TGFbeta1 production can turn a well-controlled healing response into a pathogenic fibrotic response. Endogenous regulatory mechanisms are discussed including novel areas of therapeutic intervention. Restoring homeostasis to these dysregulated healing responses, or simply neutralizing the key pro-fibrotic mediators may prevent or slow the progression of pulmonary fibrosis.

IL-9- and mast cell-mediated intestinal permeability predisposes to oral antigen hypersensitivity

Previous mouse and clinical studies demonstrate a link between Th2 intestinal inflammation and induction of the effector phase of food allergy. However, the mechanism by which sensitization and mast cell responses occurs is largely unknown. We demonstrate that interleukin (IL)-9 has an important role in this process. IL-9-deficient mice fail to develop experimental oral antigen-induced intestinal anaphylaxis, and intestinal IL-9 overexpression induces an intestinal anaphylaxis phenotype (intestinal mastocytosis, intestinal permeability, and intravascular leakage). In addition, intestinal IL-9 overexpression predisposes to oral antigen sensitization, which requires mast cells and increased intestinal permeability. These observations demonstrate a central role for IL-9 and mast cells in experimental intestinal permeability in oral antigen sensitization and suggest that IL-9-mediated mast cell responses have an important role in food allergy.

Eosinophils: biological properties and role in health and disease

Eosinophils are pleiotropic multifunctional leukocytes involved in initiation and propagation of diverse inflammatory responses, as well as modulators of innate and adaptive immunity. In this review, the biology of eosinophils is summarized, focusing on transcriptional regulation of eosinophil differentiation, characterization of the growing properties of eosinophil granule proteins, surface proteins and pleiotropic mediators, and molecular mechanisms of eosinophil degranulation. New views on the role of eosinophils in homeostatic function are examined, including developmental biology and innate and adaptive immunity (as well as their interaction with mast cells and T cells) and their proposed role in disease processes including infections, asthma, and gastrointestinal disorders. Finally, strategies for targeted therapeutic intervention in eosinophil-mediated mucosal diseases are conceptualized.

The impact of comorbid atopic disease on asthma: clinical expression and treatment

Clinically, asthma and allergic rhinitis involve separate regions of the respiratory tract while representing a common underlying inflammatory syndrome. Much evidence supports an epidemiologic association between the diseases, paranasal sinus involvement in both conditions, and parallel relationship in severity and treatment outcomes. Pathophysiologic mechanisms, including immunoglobulin E (IgE)- mediated inflammation, are also shared. Blocking IgE with the recombinant humanized monoclonal antibody omalizumab demonstrated clinical efficacy in patients with upper and lower airway diseases. IgE blockade, leukotriene modulation, and B-cell depletion therapy have all exhibited success in chronic inflammation, reinforcing and expanding the beneficial role of immunomodulation of global mediators.

IL-2-induced IL-9 production by allergen-specific human helper T-cell clones

BACKGROUND

IL-9 is an important cytokine in allergic diseases such as asthma, atopic dermatitis, etc. T helper (Th) cells seem to be the main source of IL-9. Cellular and molecular mechanisms of IL-9 production by human Th cells have been poorly understood.

METHODS

Dermatophagoides farinae(Der f)-specific Th clones were established from peripheral blood lymphocytes of atopic asthmatics, and cytokine synthesis in response to various stimuli was determined by specific ELISAs.

RESULTS

IL-9 was produced by 14 of 27 human Th clones upon T cell receptor (TCR) stimulation, immobilized anti-CD3 antibody (Ab). IL-9 production was significantly enhanced by the addition of anti-CD28 Ab into the culture, indicating the role of costimulatory signal on IL-9 synthesis. Pharmacologically, IL-9 production was induced by ionomycin (IOM) alone, and enhanced by phorbol 12-myristate 13-acetate (PMA). rIL-2 induced IL-9 production by 8 out of 19 Th clones. IL-9 production by Th clones stimulated with immobilized anti-CD3 Ab was significantly suppressed by the addition of anti-IL-2 neutralizing Ab into the culture.

CONCLUSION

Approximately half of the Der f-specific Th clones derived from atopic asthmatics produced IL-9 upon TCR stimulation. Ca(2+) signal, CD28 signal, and IL-2 receptor signal seem to play important roles in IL-9 production by human Th cells. Moreover, synthesis of IL-9, a Th2 cytokine, is dependent on IL-2, a Th1 cytokine, which is produced by Th cells themselves.

Specific and redundant roles for NFAT transcription factors in the expression of mast cell-derived cytokines

By virtue of their ability to express a plethora of biologically highly active mediators, mast cells (MC) are involved in both adaptive and innate immune responses. MC-derived Th2-type cytokines are thought to act as local amplifiers of Th2 reactions, including chronic inflammatory disorders such as allergic asthma, whereas MC-derived TNF-alpha is a critical initiator of antimicrobial defense. In this study, we demonstrate that the transcription factors NFATc1 and NFATc2 are part of a MC-specific signaling network that regulates the expression of TNF-alpha and IL-13, whereas NFATc3 is dispensable. Primary murine bone marrow-derived MC from NFATc2(-/-) mice, activated by either ionomycin or IgE/Ag cross-link, display a strong reduction in the production of these cytokines, compared with bone marrow-derived MC from wild-type mice. Detailed analyses of TNF-alpha and IL-13 expression using small interfering RNA-mediated knockdown reveals that both NFATc2 and NFATc1 are able to drive the expression of these cytokines, whereas neither degranulation nor the expression of IL-6 depends on NFAT activity. These results support the view that high NFAT activity is necessary for TNF-alpha and IL-13 promoter induction in MC, irrespective of whether NFATc2 or NFATc1 or a combination of both is present.