Different challenge terms determine disease patterns of antigen-induced pulmonary inflammation in E3 rats

Modulative effect of a new hydrazide derivative on wheat-induced pulmonary inflammation in rats

NEW FINDINGS

What is the central question of this study? What is the mechanism of wheat-induced pulmonary inflammation and how does a hydrazide derivative modulate it? What is the main finding and its importance? A hydrazide derivative significantly reduced wheat-induced pulmonary inflammation in a rat model mainly by down-regulating inflammatory cell infiltration, pathological lesions in the lungs and the level of pro-inflammatory cytokines, COX-1, COX-2 and T-cell proliferation.

ABSTRACT

We investigated the ameliorative anti-inflammatory effect of a previously synthesized hydrazide derivative (N'-(4-methoxybenzylidene)-6-(4-chlorophenyl)-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carbohydrazide; MD) as an immunomodulator in a newly developed allergen-induced pulmonary inflammation (AIPI) rat model. Wheat and thresher dust were used as allergens to induce pulmonary inflammation while MD was used to reverse the inflammatory response. Blood and bronchoalveolar lavage fluid (BALF) were collected after killing the rats and inflammatory cells were counted. Histological analysis of lung airways was carried out by haematoxylin and eosin and periodic acid-Schiff staining while the level of total serum IgE, interleukin (IL)-4, IL-5 and cyclooxygenase (COX)-1 in BALF and in vitro T-cell proliferation in spleen were measured through enzyme-linked immunosorbent assay. mRNA expression level of IL-4, IL-5, IL-13, transforming growth factor β (TGF-β), interferon-γ, tumour necrosis factor α, COX-1 and COX-2 was evaluated by qRT-PCR. A liver and kidney function test was used to observe any toxic impact of MD. The results indicated that 2 mg of wheat and thresher dust led to higher levels of inflammatory cytokines in the blood, BALF and lung airways of rats. MD potentially down-regulated the inflammatory cell infiltration in BALF and pathological lesions in the lung airways of AIPI rats. MD significantly suppressed the elevated total serum IgE, along with IL-4, IL-5, IL-13, TGF-β, COX-1 and COX-2 mRNA expression and T-cell proliferation in spleen. In conclusion, MD at 10 mg kg^-1 exhibited a significant reduction in all the markers in both wheat- and thresher dust-induced pulmonary inflammation mainly by inhibiting pro-inflammatory cytokine production and T-cell proliferation. The data suggest that inhibition of the T-cell response may be responsible for the modulative effect of MD in an AIPI rat model.

Extracellular microRNA-21 and microRNA-26a increase in body fluids from rats with antigen induced pulmonary inflammation and children with recurrent wheezing

Background

This study aims to find out whether extracellular miRNAs is implicated in recurrent childhood wheezing with asthmatic risk.

Methods

One hundred and forty children of Chinese Han population were recruited for this study. Plasma and intracellular miRNAs from children with recurrent wheezing and rats with antigen induced pulmonary inflammation (AIPI) were detected by using reverse transcription-quantitative PCR. Differential leukocytes in blood were automatically counted. Total IgE was detected by enzyme-linked immunosorbent assay. Clinical implication in diagnosis was evaluated using receiver operating characteristic curves.

Results

The increase of plasma miR-21 and miR-26a was screened out from 11 candidate miRNAs and validated in wheezing children. The level of expression for both miRNAs were comparable in different age and gender. Plasma miR-21 was more preferable to miR-26a and total IgE for diagnosis. Plasma miR-21 and miR-26a levels were not significantly correlated with various leukocyte counts or miRNA expression in blood cells. In acute and chronic AIPI rats, miR-21 levels increased in both plasma and lavaged lung compared with control. Moreover, circulating miR-21 and miR-26a levels were highly positively correlated with infiltrated cell counts in bronchoalveolar lavage fluid of AIPI rats.

Conclusions

Circulating miR-21 and miR-26a increase in wheezing children and AIPI rats. This not only manifests their strong clinical implication in recurrent childhood wheezing with asthma risk, but also provides novel insights into the role of extracellular miRNAs during development of airway inflammation and recurrent wheezing.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0216-2) contains supplementary material, which is available to authorized users.

PRMT1 Upregulated by Epithelial Proinflammatory Cytokines Participates in COX2 Expression in Fibroblasts and Chronic Antigen-Induced Pulmonary Inflammation

Protein arginine methyltransferase (PRMT)1, methylating both histones and key cellular proteins, has emerged as a key regulator of various cellular processes. This study aimed to identify the mechanism that regulates PRMT1 in chronic Ag-induced pulmonary inflammation (AIPI) in the E3 rat asthma model. E3 rats were challenged with OVA for 1 or 8 wk to induce acute or chronic AIPI. Expression of mRNAs was detected by real-time quantitative PCR. PRMT1, TGF-β, COX2, and vascular endothelial growth factor protein expression in lung tissues was determined by immunohistochemistry staining and Western blotting. In the in vitro study, IL-4-stimulated lung epithelial cell (A549) medium (ISEM) with or without anti-TGF-β Ab was applied to human fibroblasts from lung (HFL1). The proliferation of HFL1 was determined by MTT. AMI-1 (pan-PRMT inhibitor) was administered intranasally to chronic AIPI rats to determine PRMT effects on asthmatic parameters. In lung tissue sections, PRMT1 expression was significantly upregulated, mainly in epithelial cells, in acute AIPI lungs, whereas it was significantly upregulated mainly in fibroblasts in chronic AIPI lungs. The in vitro study revealed that ISEM elevates PRMT1, COX2, and vascular endothelial growth factor expressions, and it promoted fibroblast proliferation. The application of anti-TGF-β Ab suppressed COX2 upregulation by ISEM. AMI-1 inhibited the expression of COX2 in TGF-β-stimulated cells. In the in vivo experiment, AMI-1 administered to AIPI rats reduced COX2 production and humoral immune response, and it abrogated mucus secretion and collagen generation. These findings suggested that TGF-β-induced PRMT1 expression participates in fibroblast proliferation and chronic airway inflammation in AIPI.

Amelioration of ovalbumin induced allergic symptoms in Balb/c mice by potentially probiotic strains of lactobacilli

To evaluate the antiallergic effect of newly characterised probiotic strains, Lactobacillus fermentum NWS29, Lactobacillus casei NWP08 and Lactobacillus rhamnosus NWP13, mice were divided into six experimental groups: control, ovalbumin (OVA), NWS29, NWP08, NWP13 and L. rhamnosus GG (LGG). Mice were immunised and probiotics were administered via oral gavage followed by challenge with OVA. After last challenge with OVA, inflammatory cells in bronchoalveolar lavage fluid (BALF), recruitment of inflammatory cells in airways and OVA-specific immunoglobulin E (IgE) in serum were determined by Giemsa, haematoxylin and eosin (HE) staining, and ELISA, respectively. Relative mRNA expression of interleukins (IL-4, IL-5, IL-10, IL-13 and IL-17), transforming growth factor-β (TGF-β) and interferon-γ (IFN-γ) in lung and spleen tissue was determined by real time RT-PCR. OVA-specific IgE levels, recruitment of eosinophils and mRNA expressions of inflammatory cytokines were remarkably increased in OVA-exposed mice compared with the control group. Administration of NWS29 and NWP13 suppressed inflammatory cell infiltration in airways and BALF, and level of OVA-specific IgE in serum of OVA-exposed mice. Furthermore, NWS29 and NWP13 also abrogated the mRNA expression of 1L-4, IL-5, IL-13 and TGF-β in mice immunised and exposed to OVA. Our findings suggest that NWS29 and NWP13 might be good candidates for the prevention of allergic airway inflammation.

Upregulated protein arginine methyltransferase 1 by IL-4 increases eotaxin-1 expression in airway epithelial cells and participates in antigen-induced pulmonary inflammation in rats

Protein arginine methyltransferases (PRMTs), catalyzing methylation of both histones and other cellular proteins, have emerged as key regulators of various cellular processes. This study aimed to identify key PRMTs involved in Ag-induced pulmonary inflammation (AIPI), a rat model for asthma, and to explore the role of PRMT1 in the IL-4-induced eosinophil infiltration process. E3 rats were i.p. sensitized with OVA/alum and intranasally challenged with OVA to induce AIPI. The expressions of PRMT1-6, eotaxin-1, and CCR3 in lungs were screened by real-time quantitative PCR. Arginine methyltransferase inhibitor 1 (AMI-1, a pan-PRMT inhibitor) and small interfering RNA-PRMT1 were used to interrupt the function of PRMT1 in A549 cells. In addition, AMI-1 was administrated intranasally to AIPI rats to observe the effects on inflammatory parameters. The results showed that PRMT1 expression was mainly expressed in bronchus and alveolus epithelium and significantly upregulated in lungs from AIPI rats. The inhibition of PRMTs by AMI-1 and the knockdown of PRMT1 expression were able to downregulate the expressions of eotaxin-1 and CCR3 with the IL-4 stimulation in the epithelial cells. Furthermore, AMI-1 administration to AIPI rats can also ameliorate pulmonary inflammation, reduce IL-4 production and humoral immune response, and abrogate eosinophil infiltration into the lungs. In summary, PRMT1 expression is upregulated in AIPI rat lungs and can be stimulated by IL-4. Intervention of PRMT1 activity can abrogate IL-4-dependent eotaxin-1 production to influence the pulmonary inflammation with eosinophil infiltration. The findings may provide experimental evidence that PRMT1 plays an important role in asthma pathogenesis.