IL-1 Receptor antagonist as a positional candidate gene in a murine model of allergic asthma

Interleukin-1 receptor antagonist (IL-1ra) is an inhibitor of the proinflammatory IL-1. The IL-1ra gene (Il1rn) maps near the allergen-induced bronchial hyper-responsiveness-1 locus, Abhr1, which we previously mapped to murine chromosome 2 using A/J (asthma susceptible) and C3H/HeJ (asthma resistant) mice. We evaluated the role of Il1rn in our mouse model by comparing its genomic sequence between A/J and C3H/HeJ mice as well as assessing strain-specific RNA and protein production in response to allergen. We identified no functional sequence variations in the Il1rn gene between A/J and C3H/HeJ mice. Il1rn mRNA and protein were induced by ovalbumin (OVA) exposure in both strains, but to a greater extent in A/J mice at the earlier time points. We examined other IL-1 family members (Il1a, Il1b, Il1f9, and Il1r2) and found OVA-induced expression increases at 6 h, yet only Il1b and Il1f9 had strain-specific differences. Of these, only Il1f9 is located within Abhr1, and we found several non-coding polymorphisms in the Il1f9 gene between A/J and C3H/HeJ mice. Our results exclude Il1rn as the gene for Abhr1 and indicate that Il1f9 warrants further investigation based on genetic and expression differences observed in our mouse model of allergic asthma.Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

A murine IL-4 receptor antagonist that inhibits IL-4- and IL-13-induced responses prevents antigen-induced airway eosinophilia and airway hyperresponsiveness

The closely related Th2 cytokines, IL-4 and IL-13, share many biological functions that are considered important in the development of allergic airway inflammation and airway hyperresponsiveness (AHR). The overlap of their functions results from the IL-4R alpha-chain forming an important functional signaling component of both the IL-4 and IL-13 receptors. Mutations in the C terminus region of the IL-4 protein produce IL-4 mutants that bind to the IL-4R alpha-chain with high affinity, but do not induce cellular responses. A murine IL-4 mutant (C118 deletion) protein (IL-4R antagonist) inhibited IL-4- and IL-13-induced STAT6 phosphorylation as well as IL-4- and IL-13-induced IgE production in vitro. Administration of murine IL-4R antagonist during allergen (OVA) challenge inhibited the development of allergic airway eosinophilia and AHR in mice previously sensitized with OVA. The inhibitory effect on airway eosinophilia and AHR was associated with reduced levels of IL-4, IL-5, and IL-13 in the bronchoalveolar lavage fluid as well as reduced serum levels of OVA-IGE: These observations demonstrate the therapeutic potential of IL-4 mutant protein receptor antagonists that inhibit both IL-4 and IL-13 in the treatment of allergic asthma.     

Histamine 4 receptor activation induces recruitment of FoxP3+ T cells and inhibits allergic asthma in a murine model

Histamine has an important role in regulation of immune response which is mediated by differential expression of four distinct receptors, H1R-H4R. H1R and HR2 have previously been shown to be involved with modulation of lung inflammation. H4R is also expressed on inflammatory cells; therefore, we investigated the potential role of H4R in development of allergic asthma in a murine model. We determined that the H4R agonist 4-methylhistamine when delivered intratracheally before Ag challenge mitigated airway hyperreactivity and inflammation. This was associated with an increase in IL-10 and IFN-gamma, but not TGF-beta or IL-16, as well as a decrease in IL-13 in the bronchoalveolar lavage fluid. We also observed that H4R agonist instillation resulted in accumulation of FoxP3(+) T cells suggesting a direct effect on T regulatory cell recruitment. To investigate this further, we determined the in vitro effect of H4R stimulation on human T cell migration. The H4R agonist induced a 2- to 3-fold increase in T cell migration, similar to that seen for H1R agonists. Cells transmigrating to the H4R agonist, but not H1R, were skewed toward a CD4 cell expressing CD25 and intracellular FoxP3. H4R-responsive cells suppressed proliferation of autologous T cells, an effect that was dependent on IL-10 production. We conclude that H4R stimulation enriches for a regulatory T cell with potent suppressive activity for proliferation. These findings identify a novel function for H4R and suggest a potential therapeutic approach to attenuation of asthmatic inflammation.     

Anti-IL-33 antibody treatment inhibits airway inflammation in a murine model of allergic asthma

Interleukin (IL)-33 is a recently described member of the IL-1 family and has been shown to induce production of T helper type 2 cytokines. In this study, an anti-IL-33 antibody was evaluated against pulmonary inflammation in mice sensitized and challenged with ovalbumin. The anti-IL-33 or a control antibody (150 μg/mouse) was given intraperitoneally as five doses before the sensitization and antigen challenge. Treatment with anti-IL-33 significantly reduced serum IgE secretion, the numbers of eosinophils and lymphocytes, and concentrations of IL-4, IL-5, and IL-13 in bronchoalveolar lavage fluid compared with administration of a control antibody. Histological examination of lung tissue demonstrated that anti-IL-33 significantly inhibited allergen-induced lung eosinophilic inflammation and mucus hypersecretion. Our data demonstrate for the first time that anti-IL-33 antibody can prevent the development of asthma in a mouse model and indicate that blockade of IL-33 may be a new therapeutic strategy for allergic asthma.     

In vivo intranasal anti-CD23 treatment inhibits allergic responses in a murine model of allergic rhinitis

Although CD23-dependent transcytosis of IgE and IgE-derived immune complexes across respiratory epithelial cells is likely to play a pivotal role in the initiation and development of airway allergic inflammation, there is currently a lack of physiological support for this phenomena to suggest that the targeting of CD23 could be used as a means of therapeutic intervention. The present study was designed to detect the CD23 expression in the nasal mucosa of allergic rhinitis (AR) murine model by immunohistochemistry and western blotting, and to investigate whether intranasal anti-CD23 treatment could inhibit allergen-induced upper airway inflammation in the AR model. This is the first report to show that CD23 was constitutively expressed in murine nasal epithelial cells, and its expression was significantly up-regulated in the AR murine model. In vivo, the up-regulation of CD23 expression was correlated with increased serum IL-4 levels. Following intranasal anti-CD23 treatment, nasal symptoms were alleviated and histopathologic examination showed a significant decrease in eosinophilic infiltration. Meanwhile, ELISA analysis showed levels of serum leukotriene C4 (LTC4), eosinophil cation protein (ECP), ovalbumin (OVA)-specific IgE and IL-4 also significantly decreased, as were LTC4 and OVA-specific IgE in the nasal lavage fluid. Furthermore, Western blotting analysis showed that ECP expression in the nasal mucosa was down-regulated. Finally, flow cytometric analysis revealed anti-CD23 treatment inhibited Th2 cell responses. These results indicate that intranasal anti-CD23 treatment can reduce allergic responses in a murine model of allergic rhinitis.     

Soluble IL-4 receptor inhibits airway inflammation following allergen challenge in a mouse model of asthma

In vitro and in vivo studies, in both animal models and human asthmatics, have implicated IL-4 as an important inflammatory mediator in asthma. In a murine asthma model, we examined the anti-inflammatory activities of soluble IL-4R (sIL-4R). In this model, mice sensitized to OVA by i.p. and intranasal (i.n.) routes are challenged with the allergen by i.n. administration. The OVA challenge elicits an eosinophil infiltration into the lungs, with widespread mucus occlusion of the airways, and results in bronchial hyperreactivity. sIL-4R (0.1-100 microgram) was administered by either i.n. or i.p. routes before OVA challenge in OVA-sensitized mice. Both blood and bronchoalveolar lavage fluid levels of sIL-4R were significantly elevated compared with controls by i.n. delivery of 100 microgram sIL-4R; i.p. delivery of 100 microgram sIL-4R only raised blood levels of sIL-4R. The i.n. administration of 100 microgram sIL-4R before allergen challenge significantly reduced late phase pulmonary inflammation, blocking airway eosinophil infiltration, VCAM-1 expression, and mucus hypersecretion. In contrast, i.p. delivery of 100 microgram sIL-4R inhibited only the influx of eosinophils into the lungs, but not airway mucus release. Furthermore, sIL-4R treatment by either i.n. or i.p. routes did not reduce airway hyperreactivity in response to methacholine challenge. Thus, elevating airway levels of sIL-4R through the administration of exogenous sIL-4R is effective in blocking the late phase pulmonary inflammation that occurs in this murine allergen-challenge asthma model. These results suggest that sIL-4R may have beneficial anti-inflammatory effects in asthmatic patients.     

Overexpression of IL-15 in vivo enhances Tc1 response, which inhibits allergic inflammation in a murine model of asthma

IL-15, a pleiotropic cytokine, is involved in the inflammatory responses in various infectious and autoimmune diseases. We have recently constructed IL-15-transgenic (Tg) mice, which have an increased number of memory-type CD8+ T cells in the peripheral lymphoid tissues. In the present study, we found that eosinophilia and Th2-type cytokine production in the airway were severely attenuated in OVA-sensitized IL-15-Tg mice following OVA inhalation. IL-15-Tg mice preferentially developed Tc1 responses mediated by CD8+ T cells after OVA sensitization, and in vivo depletion of CD8+ T cells by anti-CD8 mAb aggravated the allergic airway inflammation in IL-15-Tg mice following OVA inhalation. Adoptive transfer of CD8+ T cells from OVA-sensitized IL-15-Tg mice into normal mice before OVA sensitization suppressed Th2 response to OVA in the normal mice. These results suggest that overexpression of IL-15 in vivo suppresses Th2-mediated-allergic airway response via induction of CD8+ T cell-mediated Tc1 response.     

IL-13 receptor alpha2 selectively inhibits IL-13-induced responses in the murine lung

IL-13 is a critical cytokine at sites of Th2 inflammation. In these locations it mediates its effects via a receptor complex, which contains IL-4Ralpha and IL-13Ralpha1. A third, high-affinity IL-13 receptor, IL-13Ralpha2, also exists. Although it was initially felt to be a decoy receptor, this has not been formally demonstrated and the role(s) of this receptor has recently become controversial. To define the role(s) of IL-13Ralpha2 in IL-13-induced pulmonary inflammation and remodeling, we compared the effects of lung-targeted transgenic IL-13 in mice with wild-type and null IL-13Ralpha2 loci. We also investigated the effect of IL-13Ralpha2 deficiency on the OVA-induced inflammatory response. In this study, we show that in the absence of IL-13Ralpha2, IL-13-induced pulmonary inflammation, mucus metaplasia, subepithelial fibrosis, and airway remodeling are significantly augmented. These changes were accompanied by increased expression and production of chemokines, proteases, mucin genes, and TGF-beta1. Similarly, an enhanced inflammatory response was observed in an OVA-induced phenotype. In contrast, disruption of IL-13Ralpha2 had no effect on the tissue effects of lung-targeted transgenic IL-4. Thus, IL-13Ralpha2 is a selective and powerful inhibitor of IL-13-induced inflammatory, remodeling, and physiologic responses in the murine lung.     

CARMA1 is necessary for optimal T cell responses in a murine model of allergic asthma

CARMA1 is a lymphocyte-specific scaffold protein necessary for T cell activation. Deletion of CARMA1 prevents the development of allergic airway inflammation in a mouse model of asthma due to a defect in naive T cell activation. However, it is unknown if CARMA1 is important for effector and memory T cell responses after the initial establishment of inflammation, findings that would be more relevant to asthma therapies targeted to CARMA1. In the current study, we sought to elucidate the role of CARMA1 in T cells that have been previously activated. Using mice in which floxed CARMA1 exons can be selectively deleted in T cells by OX40-driven Cre recombinase (OX40(+/Cre)CARMA1(F/F)), we report that CD4(+) T cells from these mice have impaired T cell reactivation responses and NF-κB signaling in vitro. Furthermore, in an in vivo recall model of allergic airway inflammation that is dependent on memory T cell function, OX40(+/Cre)CARMA1(F/F) mice have attenuated eosinophilic airway inflammation, T cell activation, and Th2 cytokine production. Using MHC class II tetramers, we demonstrate that the development and maintenance of Ag-specific memory T cells is not affected in OX40(+/Cre)CARMA1(F/F) mice. In addition, adoptive transfer of Th2-polarized OX40(+/Cre)CARMA1(F/F) Ag-specific CD4(+) T cells into wild-type mice induces markedly less airway inflammation in response to Ag challenge than transfer of wild-type Th2 cells. These data demonstrate a novel role for CARMA1 in effector and memory T cell responses and suggest that therapeutic strategies targeting CARMA1 could help treat chronic inflammatory disorders such as asthma.     

V75R576 IL-4 receptor alpha is associated with allergic asthma and enhanced IL-4 receptor function

Asthma is a complex polygenic disease. Many studies have implicated the importance of IL-4R alpha in the development of allergic inflammation and its gene has been implicated in the genetics of asthma and atopy. In this study, we examined the functional consequences of two of the human IL-4R alpha allelic variants that have been found to associate with asthma and atopy. We examined the effects of each variant alone and in combination on IL-4-dependent gene induction. We found that neither the Q576R nor the I75V variants affected IL-4-dependent CD23 expression. However, the combination of V75R576 resulted in expression of an IL-4R alpha with enhanced sensitivity to IL-4. We next examined the genetics of five of the known IL-4R alpha allelic variants in asthmatic and nonatopic populations. Strikingly, the association of V75/R576 with atopic asthma was greater than either allele alone and the association of R576 with atopic asthma was dependent on the coexistence of V75. A haplotype analysis revealed a single IL-4R alpha haplotype that was associated with allergic asthma, VACRS, further confirming the importance of the V75 and R576 combination in the genetics of asthma. This is the first report demonstrating that a functional alteration in IL-4R alpha requires the coexistence of two naturally occurring single nucleotide polymorphisms (snps) in combination; neither snp alone is sufficient. These data illustrate the importance of studying snps in combination, because the functional significance of a given snp may only be evident in a specific setting of additional snps in the same or different genes.     

Severe vitamin E deficiency modulates airway allergic inflammatory responses in the murine asthma model

Allergic asthma is a complex immunologically mediated disease associated with increased oxidative stress and altered antioxidant defenses. It was hypothesized that alpha-tocopherol (alpha-T) decreases oxidative stress and therefore its absence may influence allergic inflammatory process, a pathobiology known to be accompanied by oxidative stress. Therefore, selected parameters of allergic asthma sensitization and inflammation were evaluated following ovalbumin sensitization and re-challenge of alpha-T transfer protein (TTP) knock-out mice (TTP(-/-)) that have greatly reduced lung alpha-T levels (e.g.<5%) compared to their litter mate controls (TTP(+/+)). Results showed that severe alpha-T deficiency result in a blunted lung expression of IL-5 mRNA and IL-5 protein and plasma IgE levels compared with TTP(+/+) mice following immune sensitization and rechallenge, although lung lavage eosinophil levels were comparable in both genomic strains. It is concluded that the initial stimulation of immune responses by the TTP(-/-) mice were generally blunted compared to the TTP(+/+) mice, thus diminishing some aspects of subsequent allergic inflammatory processes.     

The role of sphingosine kinase in a murine model of allergic asthma

Asthma is an allergic disease characterized by chronic airway eosinophilia and pulmonary infiltration of lymphocytes, particularly of the Th2 subtype, macrophages and mast cells. Previous studies have shown a pivotal role for sphingosine kinase (SphK) on various proinflammatory cells, such as lymphocyte and eosinophil migration and mast cell degranulation. We therefore examined the roles of SphK in a murine model of allergic asthma. In mice previously sensitized to OVA, i.p. administration of N,N-dimethylsphingosine (DMS), a potent SphK inhibitor, significantly reduced the total inflammatory cell infiltrate and eosinophilia and the IL-4, IL-5, and eotaxin levels in bronchoalveolar lavage fluid in response to inhaled OVA challenge. In addition, DMS significantly suppressed OVA-induced inflammatory infiltrates and mucus production in the lungs, and airway hyperresponsiveness to methacholine in a dose-dependent manner. OVA-induced lymphocyte proliferation and IL-4 and IL-5 secretion were reduced in thoracic lymph node cultures from DMS-treated mice. Moreover, similar reduction in inflammatory infiltrates, bronchoalveolar lavage, IL-4, IL-5, eotaxin, and serum OVA-specific IgE levels was observed in mice with SphK1 knock-down via small interfering RNA approach. Together, these data demonstrate the therapeutic potential of SphK modulation in allergic airways disease.     

Polyopes affinis alleviates airway inflammation in a murine model of allergic asthma

Marine algae have been utilized in food as well as medicine products for a variety of purposes. The purpose of this study was to determine whether an ethanol extract of Polyopes affinis (P.affinis) can inhibit the pathogenesis of T helper 2 (Th2)-mediated allergen-induced airway inflammation in a murine model of asthma. Mice that were sensitized and challenged with ovalbumin (OVA) evidenced typical asthmatic reactions such as the following: an increase in the number of eosinophils in the bronchoalveolar lavage (BAL) fluid; a marked influx of inflammatory cells into the lung around blood vessels and airways as well as the narrowing of the airway luminal; the development of airway hyperresponsiveness (AHR); the presence of pulmonary Th2 cytokines; and the presence of allergenspecific immunoglobulin E (IgE) in the serum. The successive intraperitoneal administration of P. affinis ethanolic extracts before the last airway OVA-challenge resulted in a significant inhibition of all asthmatic reactions. These data suggest that P. affinis ethanolic extracts possess therapeutic potential for the treatment of pulmonary allergic disorders such as allergic asthma.     

Eosinophilopoiesis in a murine model of allergic airway eosinophilia: involvement of bone marrow IL-5 and IL-5 receptor alpha

The airway inflammation in asthma is dominated by eosinophils. The aim of this study was to elucidate the contribution of newly produced eosinophils in airway allergic inflammation and to determine mechanisms of any enhanced eosinophilopoiesis. OVA-sensitized BALB/c mice were repeatedly exposed to allergen via airway route. Newly produced cells were identified using a thymidine analog, 5-bromo-2'-deoxyuridine, which is incorporated into DNA during mitosis. Identification of IL-5-producing cells in the bone marrow was performed using FACS. Bone marrow CD3+ cells were enriched to evaluate IL-5-protein release in vitro. Anti-IL-5-treatment (TRFK-5) was given either systemically or directly to the airways. IL-5R-bearing cells were localized by immunocytochemistry. Repeated airway allergen exposure caused prominent airway eosinophilia after three to five exposures, and increased the number of immature eosinophils in the bone marrow. Up to 78% of bronchoalveolar lavage (BAL) granulocytes were 5-bromo-2'-deoxyuridine positive. After three allergen exposures, both CD3+ and non-CD3 cells acquired from the bone marrow expressed and released IL-5-protein. Anti-IL-5 given i.p. inhibited both bone marrow and airway eosinophilia. Intranasal administration of anti-IL-5 also reduced BAL eosinophilia, partly via local effects in the airways. Bone marrow cells, but not BAL eosinophils, displayed stainable amounts of the IL-5R alpha-chain. We conclude that the bone marrow is activated by airway allergen exposure, and that newly produced eosinophils contribute to a substantial degree to the airway eosinophilia induced by allergen. Airway allergen exposure increases the number of cells expressing IL-5-protein in the bone marrow. The bone marrow, as well as the lung, are possible targets for anti-IL-5-treatment.     

A PAF receptor antagonist inhibits acute airway inflammation and late-phase responses but not chronic airway inflammation and hyperresponsiveness in a primate model of asthma

We have examined the effects of a PAF receptor antagonist, WEB 2170, on several indices of acute and chronic airway inflammation and associated changes in lung function in a primate model of allergic asthma. A single oral administration WEB 2170 provided dose related inhibition of the release of leukotriene C(4) (LTC(4)) and prostaglandin D(2) (PGD(2)) recovered and quantified in bronchoalveolar lavage (BAL) fluid obtained during the acute phase response to inhaled antigen. In addition, oral WEB 2170 treatment in dual responder primates blocked the acute influx of neutrophils into the airways as well as the associated late-phase airway obstruction occurring 6 h after antigen inhalation. In contrast, a multiple dosing regime with WEB 2170 (once a day for 7 consecutive days) failed to reduce the chronic airway inflammation (eosinophilic) and associated airway hyperresponsiveness to inhaled methacholine that is characteristic of dual responder monkeys. Thus, we conclude that the generation of PAF following antigen inhalation contributes to the development of lipid mediators, acute airway inflammation and associated late-phase airway obstruction in dual responder primates; however, PAF does not play a significant role in the maintenance of chronic airway inflammation and associated airway hyperresponsiveness in this primate model.     

A novel anti-inflammatory role of simvastatin in a murine model of allergic asthma

Statins, the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors, are effective serum cholesterol-lowering agents in clinical practice, and they may also have anti-inflammatory properties. Asthma is characterized by chronic eosinophilic inflammation in the airways, which is thought to be regulated by the activity of T lymphocytes. We therefore examined the anti-inflammatory activity of simvastatin in a murine model of allergic asthma. In mice previously sensitized to OVA, simvastatin treatment, either orally or i.p., reduced the total inflammatory cell infiltrate and eosinophilia in bronchoalveolar lavage fluid in response to inhaled OVA challenge. Simvastatin therapy i.p. was also associated with a reduction in IL-4 and IL-5 levels in bronchoalveolar lavage fluid and, at higher doses, a histological reduction in inflammatory infiltrates in the lungs. OVA-induced IL-4, IL-5, IL-6, and IFN-gamma secretion was reduced in thoracic lymph node cultures from simvastatin-treated mice. Simvastatin treatment did not alter serum total IgE or OVA-specific IgG1 and IgG2a levels. These data demonstrate the therapeutic potential of statin-sensitive pathways in allergic airways disease.     

Lipopolysaccharide binding protein potentiates airway reactivity in a murine model of allergic asthma

The development of allergic asthma is influenced by both genetic and environmental factors. Epidemiologic data often show no clear relationship between the levels of allergen and clinical symptoms. Recent data suggest that bacterial LPS may be a risk factor related to asthma severity. Airborne LPS is typically present at levels that are insufficient to activate alveolar macrophages in the absence of the accessory molecule LPS binding protein (LBP). LBP levels are markedly elevated in bronchoalveolar lavage fluids obtained from asthmatic subjects compared with those in normal controls. We hypothesized that LBP present in the lung could augment the pulmonary inflammation and airway reactivity associated with allergic asthma by sensitizing alveolar macrophages to LPS or other bacterial products and triggering them to release proinflammatory mediators. We compared wild-type (WT) and LBP-deficient mice using a defined Ag immunization and aerosol challenge model of allergic asthma. Immunized LBP-deficient mice did not develop substantial Ag-induced airway reactivity, whereas WT mice developed marked bronchoconstriction following aerosol Ag sensitization and challenge with methacholine. Similarly, production of NO synthase 2 protein and the NO catabolite peroxynitrite was dramatically higher in the lungs of WT mice following challenge compared with that in LBP-deficient mice. Thus, NO production appears to correlate with airway reactivity. In contrast, both mice developed similar pulmonary inflammatory cell infiltrates and elevated mucin production. Thus, LBP appears to participate in the development of Ag-induced airway reactivity and peroxynitrite production, but does not seem to be required for the development of pulmonary inflammation.     

Role of lysophosphatidic acid receptor LPA2 in the development of allergic airway inflammation in a murine model of asthma

Background

Lysophosphatidic acid (LPA) plays a critical role in airway inflammation through G protein-coupled LPA receptors (LPA_1-3). We have demonstrated that LPA induced cytokine and lipid mediator release in human bronchial epithelial cells. Here we provide evidence for the role of LPA and LPA receptors in Th2-dominant airway inflammation.

Methods

Wild type, LPA₁ heterozygous knockout mice (LPA₁^+/-), and LPA₂ heterozygous knockout mice (LPA₂^+/-) were sensitized with inactivated Schistosoma mansoni eggs and local antigenic challenge with Schistosoma mansoni soluble egg Ag (SEA) in the lungs. Bronchoalveolar larvage (BAL) fluids and lung tissues were collected for analysis of inflammatory responses. Further, tracheal epithelial cells were isolated and challenged with LPA.

Results

BAL fluids from Schistosoma mansoni egg-sensitized and challenged wild type mice (4 days of challenge) showed increase of LPA level (~2.8 fold), compared to control mice. LPA₂^+/- mice, but not LPA₁^+/- mice, exposed to Schistosoma mansoni egg revealed significantly reduced cell numbers and eosinophils in BAL fluids, compared to challenged wild type mice. Both LPA₂^+/- and LPA₁^+/- mice showed decreases in bronchial goblet cells. LPA₂^+/- mice, but not LPA₁^+/- mice showed the decreases in prostaglandin E2 (PGE2) and LPA levels in BAL fluids after SEA challenge. The PGE2 production by LPA was reduced in isolated tracheal epithelial cells from LPA₂^+/- mice. These results suggest that LPA and LPA receptors are involved in Schistosoma mansoni egg-mediated inflammation and further studies are proposed to understand the role of LPA and LPA receptors in the inflammatory process.     

Identification of histone acetylation in a murine model of allergic asthma by proteomic analysis

The pathogenesis of asthma is closely related to histone acetylation modification, but the specific acetylation sites related to this process remain indistinct. Herein, our study sought to identify differentially modified acetylation sites and their expression distribution in cells involved in asthma in lung tissues. The airway hyper-responsiveness, inflammation, and remodeling were assessed by non-invasive whole-body plethysmography, ELISA, and hematoxylin-eosin staining to confirm the successful establishment of the allergic asthma model. Afterward, the differentially modified acetylation sites in asthmatic lung tissues were identified and validated by using proteomics and western blotting, respectively. The immunohistochemistry analysis was applied to reveal the distribution of identified acetylation sites in asthmatic lung tissues. A total of 15 differentially modified acetylation sites, including 13 upregulated (H3K9ac, H3K14ac, H3K18ac, H3K23ac,H3K27ac, H3K36ac, H2B1KK120ac, H2B2BK20ac, H2BK16ac, H2BK20ac, H2BK108ac, H2BK116ac, and H2BK120ac) and 2 downregulated (H2BK5ac and H2BK11ac) sites were identified and validated. Furthermore, immunohistochemical staining of lung tissues showed that nine of the identified histone acetylation sites (H2BK5, H2BK11, H3K18, H2BK116, H2BK20, H2BK120, H3K9, H3K36, and H3K27) were differentially expressed in airway epithelial cells, and the acetylation of identified H3 histones were observed in both eosinophil and perivascular inflammatory cells. Additionally, differential expression of histone acetylation sites was also observed in nucleus of airway epithelial cells, vascular smooth muscle cells, perivascular inflammatory cells, and airway smooth muscle cells. In conclusion, we identified potential acetylation sites associated with asthma pathogenesis. These findings may contribute greatly in the search for therapeutic approaches for allergic asthma.