Th2-mediated Airway Inflammation Research Articles

DerP1, a house dust mite protease, directly activates airway vagal afferents and induces airway hyperreactivity after chronic exposure

Airway hyperreactivity (AHR) is one of the main symptoms of allergic asthma. Current therapeutics used in the treatment of allergic asthma do not target the AHR. Airway sensory afferents have been shown to be critical in AHR, but the mechanisms remain elusive. We have previously shown that house dust mite (HDM) extract, which contains multiple different proteases, can directly activate these airway sensory afferents in the lung via PAR1 receptors. In this study we identified the most potent protease DerP1 is capable of directly and robustly activating airway sensory vagal afferents. DerP1 caused a significant release of CGRP, a neuropeptide released after nerve terminal activation, from the airways. We observed that DerP1 caused a calcium influx in 65% of TRPV1 positive lung specific neurons. We also observed that in our two-photon ex vivo imaging of the vagal ganglia of PirtCre;R26 ‐ GCaMP6s mice, DerP1 caused a robust activation of approximately 60% of naïve airway-specific C-fibers. Calcium imaging of the lung specific vagal neurons from wild type, TRPA1 KO and TRPV1 KO revealed that the DerP1 mediated activation was absent in TRPV1 KO mice neurons. We then found that mice exposed to DerP1 chronically over a period of 12 days (without an adjuvant) had significant AHR and Th2 mediated airway inflammation. Our data suggests that direct activation of airway vagal C-fiber afferents by DerP1 via TRPV1 chronically leads to airway hyperreactivity and Th2 mediated airway inflammation. Warren Alpert Foundation. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Androgen receptor signaling decreases glutaminolysis in Th17 cells to reduce airway inflammation in asthma

Abstract Women have higher rates of severe asthma compared to men. Severe asthma has increased Th2-mediated eosinophilic and/or Th17-mediated neutrophilic airway inflammation. We showed androgens, signaling through the androgen receptor (AR), decreased Th2- and Th17-mediated airway inflammation, and that Th17 and Th2 rely on glutaminolysis during allergic airway inflammation. Therefore, we hypothesized that AR signaling decreases glutaminolysis in Th2 and Th17 cells, resulting in decreased airway inflammation. Th2 and Th17 were differentiated in vitro from wild-type male and ArTfm male mice, with a nonfunctional AR. Mitochondrial metabolism and glycolysis were determined by measuring oxygen consumption rate (OCR), reactive oxygen species (ROS), and the extracellular acidification rate (ECAR). In Th17 cells, AR signaling decreased OCR, while increasing mitochondrial ROS, suggesting decreased glutaminolysis. Further, both 5α-DHT (0.1nM) and CB839 (a glutaminase inhibitor, 0.5μM) reduced OCR in Th17 cells from male mice. AR signaling had no effect on ECAR in Th17 cells or OCR and ECAR in Th2 cells. To induce eosinophilic and neutrophilic airway inflammation, house dust mite (HDM) was intranasally administered to ArfloxedCD4-Cre and Arfloxed male mice and markers of glycolysis and glutaminolysis were determined by flow cytometry. AR signaling decreased airway neutrophils, the number of Th17 lung cells, and GLUD1, a glutaminolysis marker, expression in T cells, but had no effect on eosinophils or Th2 cells. Combined, these data showed that AR signaling decreased glutaminolysis in Th17, but not Th2, cells. Understanding these pathways may provide new potential therapeutic targets in women with difficult-to-treat asthma. Supported by grants from NIH (R01 HL12254, R01 HL136664, T32 GM007347)

CD44 is critical for the enhancing effect of hyaluronan in allergen-specific sublingual immunotherapy in a murine model of chronic asthma.

Allergen-specific sublingual immunotherapy (SLIT) is a potentially effective disease-modification treatment for patients with allergic asthma. Because CD44 signaling enhances regulatory T (Treg) cell-induction, administering CD44 ligands such as hyaluronan (HA) with allergen-specific SLIT may enhance the therapeutic effects. We evaluated the role of CD44 in Treg cell-induction in T helper type 2 (Th2)-mediated chronic airway inflammation using CD44-/- mice and the efficacy of HA on SLIT in a Dermatophagoides farinae (Df)-induced murine model of chronic asthma. Th2 responses and Treg cell induction were evaluated in CD44-/- mice. We devised a new SLIT model of Df-induced chronic asthma utilizing HA as an adjuvant. The effects of HA added to the new SLIT model were evaluated by the early asthmatic response (EAR) and airway hyperresponsiveness (AHR), eosinophilic airway inflammation, and serum Df-specific IgE levels. Th2-mediated chronic eosinophilic airway inflammation was worse in CD44-/- mice compared with Df-sensitized wild-type (WT) mice. HA enhanced the effect of Df-induced Treg cells in a CD44-dependent manner. Sublingual Df treatment in combination with HA, but not alone, normalized EAR and AHR, and significantly reduced the serum IgE levels and the bronchoalveolar lavage fluid (BALF) eosinophil number. HA also induced Treg cells in a Df-sensitized spleen cell culture in a CD44-dependent manner. The treatment-enhancing effects of HA in this SLIT model were diminished in CD44-/- mice. CD44 is a key contributor to Treg cell induction and critical for the enhancing effects of HA in a Df-induced murine model of chronic asthma.

Epicutaneous vaccination with protease inhibitor-treated papain prevents papain-induced Th2-mediated airway inflammation without inducing Th17 in mice

Environmental allergen sources such as house dust mites contain proteases, which are frequently allergens themselves. Inhalation with the exogenous proteases, such as a model of protease allergen, papain, to airways evokes release and activation of IL-33, which promotes innate and adaptive allergic airway inflammation and Th2 sensitization in mice. Here, we examine whether epicutaneous (e.c.) vaccination with antigens with and without protease activity shows prophylactic effect on the Th airway sensitization and Th2-medated airway inflammation, which are driven by exogenous or endogenous IL-33. E.c. vaccination with ovalbumin restrained ovalbumin-specific Th2 airway sensitization and/or airway inflammation on subsequent inhalation with ovalbumin plus papain or ovalbumin plus recombinant IL-33. E.c. vaccination with papain or protease inhibitor-treated papain restrained papain-specific Th2 and Th9 airway sensitization, eosinophilia, and infiltration of IL-33-responsive Th2 and group 2 innate lymphoid cells on subsequent inhalation with papain. However, e.c. vaccination with papain but not protease inhibitor-treated papain induced Th17 response in bronchial draining lymph node cells. In conclusions, we demonstrated that e.c. allergen vaccination via intact skin in mice restrained even protease allergen-activated IL-33-driven airway Th2 sensitization to attenuate allergic airway inflammation and that e.c. vaccination with protease allergen attenuated the airway inflammation similar to its derivative lacking the protease activity, although the former but not the latter promoted Th17 development. In addition, the present study suggests that modified allergens, of which Th17-inducing e.c. adjuvant activity such as the protease activity was eliminated, might be preferable for safer clinical applications of the e.c. allergen administration.

Combination of Fractional Exhaled Nitric Oxide (FeNO) Level and Asthma Control Test (ATC) in Detecting GINA-Defined Asthma Control in Treated Asthmatic Patients in Vietnam.

Background FeNO has been used as a marker for Th2-mediated airway inflammation in asthma. There is evidence which recommends the use of this biomarker in asthma management. Little is known about whether the FeNO test alone or in combination with the ACT score can reflect asthma control in Vietnamese patients. Materials and Methods A cross-sectional study was conducted in asthmatic patients (≥18 years old) recruited at the University Medical Center, Ho Chi Minh City, Vietnam from March 2016 to March 2017. Asthma control levels were assessed following the GINA 2017 guidelines, and FeNO was measured by a Niox Mino device. FeNO cut-offs predicting asthma control status were determined using the ROC curve analysis. The combination of FeNO and ACT was investigated in detecting well-controlled and uncontrolled asthma. The results of the study are as follows: 278 patients with 68% females, mean age of 44 years, and mean asthma duration of 10 years were analyzed. All patients were treated following step 2 to 4 of GINA guidelines. Mean (SD) FeNO was 30.6 (24) ppb. Patients with uncontrolled (16%), partly controlled (29%), and well-controlled asthma (55%) had a median (IQR) FeNO of 50.0 (74), 25.0 (23), and 21.0 (22.3) ppb, respectively, and the mean of FeNO in the uncontrolled group was significantly higher than that in other groups (p < 0.001). The area under the ROC curve (AUC) for FeNO detecting uncontrolled asthma was 0.730 with an optimal cut-off point of FeNO > 50 ppb, and this AUC increased to 0.89 when combining FeNO and ACT. The AUC for FeNO detecting well-controlled asthma was 0.601 with an optimal cut-off point of FeNO <25 ppb and this AUC increased to 0.78 if combining FeNO and ACT. Conclusions FeNO can predict asthma control status with an estimated cut-off point of <25 ppb for well-controlled and >50 ppb for uncontrolled asthma. The combination of FeNO and ACT provides better information regarding asthma control than FeNO alone, and this combination is useful to predict asthma control statuses in asthmatic patients in Viet Nam.

Interleukin-2/antibody complex expanding Foxp3+ regulatory T cells exacerbates Th2-mediated allergic airway inflammation

Foxp3+ regulatory CD4+ T (Treg) cells play an essential role in preventing overt immune responses against self and innocuous foreign antigens. Selective expansion of endogenous Treg cells in response to the administration of interleukin (IL)-2/antibody complex, such as the IL-2/JES6-1 complex (IL-2C) in mice, is considered an attractive therapeutic approach to various immune disorders. Here, we investigated the therapeutic potential of IL-2C in allergic airway inflammation models. IL-2C treatment ameliorated Th17-mediated airway inflammation; however, unexpectedly, IL-2C treatment exacerbated Th2-mediated allergic airway inflammation by inducing the selective expansion of Th2 cells and type-2 innate lymphoid cells. We also found that IL-2 signaling is required for the expansion of Th2 cells in lymphoproliferative disease caused by Treg cell depletion. Our data suggest that IL-2C is selectively applicable to the treatment of allergic airway diseases depending on the characteristics of airway inflammation.

Role of house dust mite-derived extracellular vesicles in a murine model of airway inflammation.

House dust mite (HDM) is the major source of indoor allergens that cause airway disease. Recent evidence suggests that Gram-negative/positive bacteria produce nano-sized extracellular vesicles (EVs) containing diverse components, including various immunostimulatory molecules. However, the association between bacteria-derived EVs and development of airway disease is unclear. To identify and isolate HDM-derived EVs and to evaluate their effect on the development of airway inflammation. Extracellular vesicles were isolated from crude HDM extracts by ultra-centrifugation, and their physical and immunological characteristics and roles in airway inflammation were tested invitro and in murine models of airway inflammation. In addition, 16s metagenome analysis of nucleic acid from EVs was performed to identify their origin. Round, bilayered vesicles measuring 80-100 nanometres and containing abundant amounts of LPS were isolated. These vesicles induced innate immune responses both invitro and invivo. Intranasal exposure of naïve mice to HDM EVs induced production of cytokines associated with development of Th2-mediated and mixed (Th1-/Th2-/Th17-mediated) airway inflammation to allergen. Metagenome analysis identified Bacteroidetes and Proteobacteria as the probable sources of HDM EVs. House dust mite EVs originating from Gram-negative bacteria may play an important role on the development of airway inflammation.

Non-apoptotic Fas (CD95) Signaling on T Cells Regulates the Resolution of Th2-Mediated Inflammation.

Fas (CD95/APO-1) and its ligand (FasL/CD95L) promote the resolution of type 2 lung inflammation and eosinophilia. We previously found that Fas-deficiency on T cells, but not eosinophils, delayed resolution of inflammation. However, Fas can signal both cell death and have a positive signaling function that can actually activate cells. In this study, we investigated whether Fas-induced death or Fas-activated signaling pathways promote resolution of allergic lung inflammation. By increasing T cell survival through two Fas-independent pathways, using Bim-deficient T cells or Bcl-xL overexpressing T cells, no differences in resolution of Th2-mediated inflammation was observed. Furthermore, Th2 cells were inherently resistant to Fas-mediated apoptosis and preferentially signaled through non-apoptotic pathways following FasL treatment. Utilizing Fas-mutant mice deficient in apoptotic but sufficient for non-apoptotic Fas signaling pathways, we demonstrate that non-apoptotic Fas signaling in T cells drives resolution of Th2-mediated airway inflammation. Our findings reveal a previously unknown role for non-apoptotic Fas signaling on Th2 cells in the induction of resolution of type 2 inflammation.

IL-27 controls allergic airway inflammation via Foxp3+ regulatory T cells

Abstract Asthma is a chronic inflammatory disease in the lung mediated by allergen reactive Th2 type CD4 T cells producing the Th2 type cytokines. We recently reported that IL-27 plays a key role in Treg functions to control Th17-mediated autoimmune inflammation. However, a role for IL-27 in modulating Treg function during Th2-mediated allergic airway inflammation remains unclear. Here, we report that during cockroach antigen (CA)-induced allergic airway inflammation, IL-27 attenuates inflammatory responses primarily via Foxp3+ Tregs. Sensitizing mice with CA in alum followed by intranasal challenge induces allergic airway inflammation characterized by infiltration of eosinophils and effector CD4 T cells expressing Th2 cytokines in the lung. Recombinant IL-27 administration prior to antigen challenge significantly reduces the inflammation. Accumulation of CD4 T cells expressing inflammatory cytokines is dramatically reduced in the inflamed sites following IL-27 administration. However, IL-27-mediated treatment effects are completely lost when Foxp3+ Tregs are deleted prior to CA challenge. Adoptive transfer of wild type Tregs restores IL-27-mediated inhibition of airway inflammation, suggesting that Tregs may be the direct responders of IL-27. IL-27 stimulation in Tregs increases expression of lymphocyte activation gene 3 (Lag3), a surface molecule implicated in Treg functions. Unlike WT type cells, adoptive transfer of Tregs deficient in Lag3 fails to attenuate airway inflammation even after IL-27 administration. Taken together, these results demonstrate a novel IL-27-dependent Treg function to control allergic airway inflammation

GATA3, SATB1, IRF4 complex binds to the Th2 cytokine locus through cis-acting element RHS6, regulating allergic airway inflammation.

Abstract Rad50 hypersensitive site 6 (RHS6) is a cis-acting element in the Th2 locus control region which is essential for the expression of Th2 cytokine genes. However, molecular mechanisms how it regulates the genes are poorly understood. We found that RHS6 recruits transcription factors GATA3, SATB1, and IRF4 during Th2 cell differentiation. GATA3, SATB1, and IRF4 have a crucial role in regulating Th2 cytokine genes. Knock-out or knock-down of each of GATA3, SATB1, and IRF4 genes significantly decrease the expression of Th2 cytokine genes. Mechanistically RHS6 mediates the transcription factor-induced regulation of Th2 cytokine genes. GATA3, SATB1, and IRF4 physically associates with each other, and forms a protein complex at RHS6 sequence. They directly bind to the many regulatory elements throughout the Th2 cytokine locus, RHS6 dependent manner. Furthermore, deletion of RHS6 caused a dramatic resistance to airway inflammation in ovalbumin-induced allergic inflammation model. Together, RHS6 recruits GATA3, SATB1, and IRF4 coordinating their regulation of Th2 cytokine genes, so is essential for Th2-mediated allergic airway inflammation.

Application of a phenotypic drug discovery strategy to identify biological and chemical starting points for inhibition of TSLP production in lung epithelial cells.

Thymic stromal lymphopoietin (TSLP) is a cytokine released by human lung epithelium in response to external insult. Considered as a master switch in T helper 2 lymphocyte (Th2) mediated responses, TSLP is believed to play a key role in allergic diseases including asthma. The aim of this study was to use a phenotypic approach to identify new biological and chemical starting points for inhibition of TSLP production in human bronchial epithelial cells (NHBE), with the objective of reducing Th2-mediated airway inflammation. To this end, a phenotypic screen was performed using poly I:C / IL-4 stimulated NHBE cells interrogated with a 44,974 compound library. As a result, 85 hits which downregulated TSLP protein and mRNA levels were identified and a representative subset of 7 hits was selected for further characterization. These molecules inhibited the activity of several members of the MAPK, PI3K and tyrosine kinase families and some of them have been reported as modulators of cellular phenotypic endpoints like cell-cell contacts, microtubule polymerization and caspase activation. Characterization of the biological profile of the hits suggested that mTOR could be a key activity involved in the regulation of TSLP production in NHBE cells. Among other targeted kinases, inhibition of p38 MAPK and JAK kinases showed different degrees of correlation with TSLP downregulation, while Syk kinase did not seem to be related. Overall, inhibition of TSLP production by the selected hits, rather than resulting from inhibition of single isolated targets, appeared to be due to a combination of activities with different levels of relevance. Finally, a hit expansion exercise yielded additional active compounds that could be amenable to further optimization, providing an opportunity to dissociate TSLP inhibition from other non-desired activities. This study illustrates the potential of phenotypic drug discovery to complement target based approaches by providing new chemistry and biology leads.

Monocyte chemotactic protein–induced protein 1 controls allergic airway inflammation by suppressing IL-5–producing TH2 cells through the Notch/Gata3 pathway

Asthmatic and allergic inflammation is mediated by TH2 cytokines (IL-4, IL-5, and IL-13). Although we have learned much about how TH2 cells are differentiated, the TH2 checkpoint mechanisms remain elusive. In this study we investigate how monocyte chemotactic protein-induced protein 1 (MCPIP1; encoded by the Zc3h12a gene) regulates IL-5-producing TH2 cell differentiation and TH2-mediated inflammation. The functions of Zc3h12a-/- CD4 T cells were evaluated by checking the expression of TH2 cytokines and transcription factors invivo and invitro. Allergic airway inflammation of Zc3h12a-/- mice was examined with murine asthma models. In addition, antigen-specific CD4 T cells deficient in MCPIP1 were transferred to wild-type recipient mice, challenged with ovalbumin (OVA) or house dust mite (HDM), and accessed for TH2 inflammation. Zc3h12a-/- mice have spontaneous severe lung inflammation, with an increase in mainly IL-5- and IL-13-producing but not IL-4-producing TH2 cells in the lung. Mechanistically, differentiation of IL-5-producing Zc3h12a-/- TH2 cells is mediated through Notch signaling and Gata3 independent of IL-4. Gata3 mRNA is stabilized in Zc3h12a-/- TH2 cells. MCPIP1 promotes Gata3 mRNA decay through the RNase domain. Furthermore, deletion of MCPIP1 in OVA- or HDM-specific T cells leads to significantly increased TH2-mediated airway inflammation in OVA or HDM murine models of asthma. Our study reveals that MCPIP1 regulates the development and function of IL-5-producing TH2 cells through the Notch/Gata3 pathway. MCPIP1 represents a new and promising target for the treatment of asthma and other TH2-mediated diseases.

Age difference in the immune response to endotoxin (LPS) shapes Th2-mediated airway inflammation and development of asthma.

Abstract In addition to genetic factors, environmental exposures is also of primary importance for the development of asthma/allergy disorders in children, as demonstrated by epidemiological data showing children growing up in traditional farms seem to develop asthma less often than children growing up in urban areas. According to the hygiene hypothesis, this is due to increased exposure to endotoxin (LPS) and other farm-related microorganism-derived compounds. However little is known about how early-life contact to microbial compounds influence the development of asthma. Here we show that house dust mite (HDM) allergen sensitization in adult mice (8 weeks-old) induced T-helper type 2 (Th2)- driven airway inflammation, i.e., influx of activated Th2 cells into the airways, airway eosinophilic inflammation and increased IgE-producing plasmablasts. In contrast, HDM allergen sensitization with low-dose LPS (10 μg) abrogated HDM-driven Th2-mediated allergic airway inflammation without increasing antigen-specific Th1 cell trafficking into the airways. Importantly, unlike adults, infant mice (3 weeks-old) exposed to HDM with low-dose LPS (10 μg) developed Th2 responses allergic airway inflammation and required allergen sensitization with high-dose LPS (100 μg) to effectively suppress allergen-specific Th2 responses and allergic inflammation. These results show that airway exposure levels of endotoxin provide different protection against asthma and allergies in adults and infants and suggest that Infants are more vulnerable to prime type 2 cell dominant responses to inhaled allergens in the presence of low dose endotoxin, which will shape future effector Th2 responses and Th2-mediated airway inflammation throughout adult life.

Mechanisms Driving Gender Differences in Asthma.

Many phenotypes of asthma exist, ranging from mild asthma with onset during childhood to severe asthma with later onset, making asthma a broad disease with different pathologies. A gender disparity exists in asthma prevalence. As adults, women have an increased asthma prevalence compared to men. Further, women are more likely to have severe asthma and a later onset of asthma compared to men. Here, we review clinical and animal studies that have defined the role of sex hormones in airway inflammation, smooth muscle contraction, mucus production, and airway mechanics associated with asthma pathogenesis. Clinical evidence shows that increased asthma symptoms occur in females starting at puberty compared to those in boys. However, after puberty, the role for sex hormones in regulating asthma symptoms during menstruation, pregnancy, and menopause is not as clear. Animal studies have shown that estrogen increases and testosterone decreases Th2-mediated airway inflammation, and that females have increased IL-17A-mediated airway inflammation compared to males. Further, females had increased DC and Mϕ function compared to males. However, the mechanisms driving the types of allergic inflammation are not fully elucidated. Overall, ovarian hormones increased and testosterone decreased airway inflammation in asthma, but the mechanisms remain unclear. Delineating these pathways using animal models as well as women and men with various phenotypes of asthma will help determine if women with asthma should take (or avoid) hormonal contraceptives as well as predict changes in asthma symptoms during life phases, including pregnancy and menopause, when sex hormones are dramatically changing.

Age Difference in the Immune Response to Endotoxin (LPS) Shapes Th2-Mediated Airway Inflammation and Development of Asthma.

Age Difference in the Immune Response to Endotoxin (LPS) Shapes Th2-Mediated Airway Inflammation and Development of Asthma.

Corrigendum to "Ferulic Acid Induces Th1 Responses by Modulating the Function of Dendritic Cells and Ameliorates Th2-Mediated Allergic Airway Inflammation in Mice".

[This corrects the article DOI: 10.1155/2015/678487.].

IL-27 attenuates airway inflammation in a mouse asthma model via the STAT1 and GADD45γ/p38 MAPK pathways.

BackgroundAsthma is prone to Th2-mediated chronic airway inflammation. Interleukin-27 (IL-27) is a member of the IL-12 family that promotes the differentiation of Th1 cells and inhibits Th2 cells. We use human/mouse CD4+ T cells to see whether IL-27 could inhibit IL-4 production in vitro and then observe whether IL-27 administration could alleviate allergic airway inflammation in vivo by mice asthma model.MethodsWe isolated and cultured CD4+ T cells from healthy humans and mice to test whether IL-27 could inhibit IL-4 production under different conditions. In vivo study, the effect of IL-27 was examined using two types of intra-nasal (i.n.) administration: low-dose-multiple-times prevention or high-dose-limited-times treatment in murine asthma models. The expression levels of signal transducer and activator of transcription-1 (STAT1) and growth arrest and DNA damage 45-γ (GADD45γ)/p38 mitogen activated protein kinase (p38 MAPK) in lung tissues were measured using qPCR and Western blotting.ResultsIn vitro, although IL-27 could inhibit naïve CD4+ T cell differentiate into Th2 cells, but it could not redifferentiate already committed Th2 cells. In vivo, preventative administration of IL-27 attenuated allergic inflammation and airway hyperreactivity, whereas treatment group had no significant effect. In the asthma group, the phosphorylation of STAT1 was impaired, while GADD45γ and p38 MAPK exhibited no obvious changes. Preventative administration of IL-27 could either reverse the impairment of STAT1 or strengthen the expression of GADD45γ and p38 MAPK, whereas treatment group had no significant effect.ConclusionsPreventative administration of IL-27 improved the pathological changes in mouse asthma models via both the STAT1 and GADD45γ/p38 MAPK pathways while therapeutic administration of IL-27 had no significant effect, which may be due to the presence of already differentiated Th2 cells in asthmatic airways that resist IL-27 inhibition.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-016-1039-x) contains supplementary material, which is available to authorized users.

Dermatophagoides pteronyssinus group 2 allergen bound to 8-OH modified adenine reduces the Th2-mediated airway inflammation without inducing a Th17 response and autoimmunity.

8-OH modified adenine bound to Dermatophagoides pteronyssinus group 2 (nDer p2-Conj), a novel allergen-TLR7 agonist conjugate, improves murine airway inflammation in priming and therapeutic settings, however no data are known on the activity of this construct on Th17 cells. The aim of the study was to evaluate if nDer p2-Conj elicited in vivo Th17 cells and Th17-driven autoimmune responses, by using both short- and long-term priming and therapeutic protocols in a nDer p2-driven model of murine airway inflammation. The conjugate induced the in vitro production of cytokines favouring the Th17 polarization by bone marrow-derived dendritic cells. In short-term protocols, the priming or treatment with the conjugate ameliorated the airway inflammation by shifting Th2 allergen-specific cells into T cells producing IFN-γ, IL-10, but not IL-17A. Similar results were found in long-term protocol where the conjugate down-regulated airway inflammation without any evidence of autoimmune response and B cell compartment expansion. nDer p2-Conj also failed to shorten the spontaneous onset of diabetes on conjugates-primed NOD/LtJ mice. We found that neutrophils in BALF, ROR-γt and IL-17A expression in lungs were increased in conjugate-treated IL-10KO mice. These data emphasize the role of conjugate-driven IL-10 production, which can regulate the activity of memory Th17 cells and prevent the onset of autoimmune response.

CD4+ Th2 cells are directly regulated by IL-10 during allergic airway inflammation

Interleukin-10 (IL-10) is an important regulatory cytokine required to control allergy and asthma. IL-10-mediated regulation of T cell-mediated responses was previously thought to occur indirectly via antigen-presenting cells. However, IL-10 can act directly on regulatory T cells and T helper type 17 (Th17) cells. In the context of allergy, it is therefore unclear whether IL-10 can directly regulate T helper type 2 (Th2) cells and whether this is an important regulatory axis during allergic responses. We sought to determine whether IL-10 signaling in CD4+ Th2 cells was an important mechanism of immune regulation during airway allergy. We demonstrate that IL-10 directly limits Th2 cell differentiation and survival in vitro and in vivo. Ablation of IL-10 signaling in Th2 cells led to enhanced Th2 cell survival and exacerbated pulmonary inflammation in a murine model of house dust mite allergy. Mechanistically, IL-10R signaling regulated the expression of several genes in Th2 cells, including granzyme B. Indeed, IL-10 increased granzyme B expression in Th2 cells and led to increased Th2 cell death, identifying an IL-10-regulated granzyme B axis in Th2 cells controlling Th2 cell survival. This study provides clear evidence that IL-10 exerts direct effects on Th2 cells, regulating the survival of Th2 cells and severity of Th2-mediated allergic airway inflammation.

Effects of immunomodulatory supplementation with pre and probiotic on Th2-mediated airway inflammation in A/J and C57BL/6 mice

Abstract Studies have demonstrated that some probiotics and prebiotics could improve Th2 airway inflammation, such as asthma disease. However, it is unclear if a specific probiotic and prebiotic could regulate asthma disease independent of genetic host and gut microbiota composition. Our objective is to elucidate if the habitual probiotic and prebiotic consumption can affect Th2-mediated airway inflammation in two inbred mice, A/J and C57BL/6 (B6). It is known that A/J have a greater Th2 airway inflammation predisposition than B6 and this fact was attributed to genetic difference. The purpose of this study is to examine the role of gut microbiota composition on Th2 inflammation predisposition and the effects of the probiotic (Bifidobacterium longum) and the prebiotic (pectin fiber) on experimental asthma on both mouse strains. Before treatment, an Ion-Torrent 16S rRNA gene-based amplification and sequencing protocol was used to determine the fecal microbiota profile. Ten days before sensitization, they were treated with probiotic or prebiotic. Experimental asthma was performed by sensitization and challenges with ovalbumin. Twenty-four hours after the last challenge, pulmonary inflammation and lung function were analyzed. Our results show that A/J mice have lower microbiota diversity than B6. Interestingly, probiotic and prebiotic treatment reduced lung inflammation and airway hyperresponsiveness, only on A/J mice. The results suggest that low microbiota diversity and genetic background can predispose Th2 airway inflammation. Moreover, high gut microbiota diversity can to strengthen the barrier function of the mucous membrane and to interfere with the effects of pre and probiotics, such as we observed in B6 mice.