Comparative effects of basophil-directed growth factors

IL-3, IL-5, and GM-CSF exert various overlapping functions in basophils. We investigated the receptor expression profiles and concentration-dependent effects of IL-3, IL-5, and GM-CSF on several basophil functions in comparison with their effects on eosinophils. The order of the receptor expression levels was IL-3Ralpha>IL-5Ralpha>GM-CSFRalpha in basophils and IL-5Ralpha>or=GM-CSFRalpha>IL-3Ralpha in eosinophils. Compared with eosinophils, basophils expressed a much higher level of IL-3Ralpha and similar levels of IL-5Ralpha and GM-CSFRalpha. The order of potency was IL-3>IL-5=GM-CSF for degranulation, survival, and CD11b expression in basophils, and IL-5=GM-CSF>or=IL-3 for survival and CD11b expression in eosinophils. However, IL-3 induced CD69 expression preferentially in basophils. Our results indicate that IL-3 is the most potent activator of human basophils, and that the rank order of potency of hemopoietic growth factors virtually corresponded to their receptor expression levels in both cell types.     

Nippostrongylus brasiliensis: phospholipase in nonsensitized and sensitized rats after challenge.

Rats given an initial infection with Nippostrongylus brasiliensis showed greatly elevated phospholipase B levels in the small intestines and lungs from 8 through 22 days after challenge. The rise in enzyme concentration occurred earlier (Days 8–11) in the proximal half of the intestine, but at Days 22, 29, and 36 the levels were much higher in the distal segments. This shift in activity correlates with the known elimination of worms and a diminishing inflammatory response in the proximal areas. The increase in enzyme activity in the intestine and lungs was associated with an increased production of eosinophils in the bone marrow 11–22 days after challenge. Rats sensitized with one stimulating infection before challenge showed an anamnestic type of response, as measured by enzyme levels in the small intestines and lungs and by the numbers of eosinophils in the bone marrow. The results are discussed in light of our similar data reported earlier from animals infected with Trichinella spiralis.     

趋化因子CCL-18 在慢性鼻- 鼻窦炎中的表达及意义

目的:分析趋化因子CCL-18在不同组织病理特征慢性鼻-鼻窦炎和正常鼻黏膜的表达差异,探讨CCL-18在慢性鼻-鼻窦炎中的表达及意义。方法:采用苏木精-伊红染色(HE),Masson染色及过碘酸-雪夫(PAS)染色对慢性鼻-鼻窦炎组织进行病理分析。采用Western blot检测CCL-18蛋白水平在不同组织病理特征慢性鼻-鼻窦炎和正常鼻黏膜组织中的表达差异。结果:CCL-18蛋白水平在伴鼻息肉和不伴有鼻息肉慢性鼻窦炎均较正常鼻黏膜组织中显著上调(P<0.05)。CCL-18蛋白水平在嗜酸性粒细胞慢性鼻窦炎的表达水平明显高于非嗜酸性粒细胞慢性鼻窦炎(P<0.05)。腺体型,纤维炎症型及水肿型慢性鼻-鼻窦炎中CCL-18表达水平均高于正常鼻黏膜,以水肿型表达最为显著(P<0.05)。结论:CCL-18在嗜酸性粒细胞和水肿型慢性鼻窦炎中高度表达,提示CCL-18可能参与慢性鼻-鼻窦炎中嗜酸性粒细胞的浸润这一基本病理过程。     

Cell death in allergic diseases

Apoptosis, the most common form of cell death, is a key mechanism in the build up and maintenance of both innate and adaptive immunity. Central to the apoptotic process is a family of intracellular cysteine proteases with aspartate-specificity, called caspases. Caspases are counter-regulated by multiple anti-apoptotic molecules, and the expression of the latter in leukocytes is largely dependent on survival factors. Therefore, the physiologic rates of apoptosis change under pathologic conditions. For instance, in inflammation, the expression of survival factors is usually elevated, resulting in increased cell survival and consequently in the accumulation of the involved immune cells. In many allergic diseases, eosinophil apoptosis is delayed contributing to both blood and tissue eosinophilia. Besides eosinophils, apoptosis of other leukocytes is also frequently prevented or delayed during allergic inflammatory processes. In contrast to inflammatory cells, accelerated cell death is often observed in epithelial cells, a mechanism, which amplifies or at least maintains allergic inflammation. In conclusion, deregulated cell death is a common phenomenon of allergic diseases that likely plays an important role in their pathogenesis. Whether the apoptosis is too little or too much depends on the cell type. In this review, we discuss the regulation of the lifespan of the participating leukocytes in allergic inflammatory responses.     

Montelukast suppresses epithelial to mesenchymal transition of bronchial epithelial cells induced by eosinophils

Epithelial to mesenchymal transition (EMT) is a mechanism by which eosinophils can induce airway remodeling. Montelukast, an antagonist of the cysteinyl leukotriene receptor, can suppress airway remodeling in asthma. The purpose of this study was to evaluate whether montelukast can ameliorate airway remodeling by blocking EMT induced by eosinophils. EMT induced was assessed using a co-culture system of human bronchial epithelial cells and human eosinophils or the eosinophilic leukemia cell lines, Eol-1. Montelukast inhibited co-culture associated morphological changes of BEAS-2b cells, decreased the expression of vimentin and collagen I, and increased the expression of E-cadherin. Montelukast mitigated the rise of TGF-β1 production and Smad3 phosphorylation. Co-culture of human eosinophils with BEAS-2B cells significantly enhanced the production of CysLTs compared with BEAS-2B cells or eosinophils alone. The increase of CysLTs was abolished by montelukast pre-treatment. Montelukast had similar effects when co-culture system of Eol-1 and BEAS-2B was used. This study showed that montelukast suppresses eosinophils-induced EMT of airway epithelial cells. This finding may explain the mechanism of montelukast-mediated amelioration of airway remodeling in bronchial asthma.     

AMCase、Eotaxin-3 及IL-13 在动物模型中的研究进展

人类疾病的动物模型（Animal Model of Human Diseases）是生物医学科学研究中所建立的动物实验对象和材料。近年来,随 着对动物模型的研究,各种人类疾病的实验模型得到广泛应用。酸性哺乳动物壳多糖酶（AMCase）作为壳多糖酶家族重要成员之 一,与其下游信号分子嗜酸性粒细胞趋化因子（eotaxin-3）以及白细胞介素13（IL-13）的级联免疫反应,近年来成为了动物模型研 究中的热点。本文总结了AMCase、eotaxin-3 及IL-13 在动物模型中的研究进展及其临床意义。     

Essential roles of endogenous glucocorticoids and TNF/TNFR1 in promoting bone-marrow eosinopoiesis in ovalbumin-sensitized,airway-challenged mice

Aims

Stress mechanisms paradoxically contribute to allergic episodes in humans and mice. Glucocorticoids (GC) and interleukin (IL)-5 synergically upregulate murine bone-marrow eosinophil production. Here we explored the role of endogenous GC in allergen-stimulated bone-marrow eosinophil production in ovalbumin-sensitized/challenged mice.

Main methods

In BALB/c or C57BL/6 mice, sensitized and intranasally challenged with ovalbumin, we monitored eosinophil numbers in freshly harvested or cultured bone-marrow, and plasma corticosterone levels. Metyrapone (MET) was used to inhibit GC synthesis, and RU486 to block GC actions. In sensitized mice challenged intraperitoneally, we examined the relationship between eosinophilia of bone-marrow and peritoneal cavity, in the absence or presence of RU486. In experiments involving in vivo neutralization of tumor necrosis factor-α (TNF) by specific antibodies, or using mice which lack functional type I TNF receptors (TNFRI), we evaluated the relationship between TNF blockade, corticosterone levels, RU486 or MET treatment and challenge-induced bone-marrow eosinophilia.

Key findings

RU486 or MET pretreatments abolished challenge-induced increases in eosinophil numbers in bone-marrow (in vivo and ex vivo), and in the peritoneal cavity. MET, but not RU486, prevented the challenge-induced increase in corticosterone levels. Challenge-induced bone-marrow eosinophilia and corticosterone surge were abolished in TNFRI-deficient mice. Anti-TNF-treatment very effectively prevented challenge-induced bone-marrow eosinophilia, in the absence of RU486 or MET, but had no independent effect in the presence of either drug.

Significance

Endogenous GC was essential for allergen challenge-induced increases in eosinophil numbers inside bone-marrow. This effect required TNF and TNFRI, which suggests an immunoendocrine mechanism.     

Synergy of Interleukin (IL)-5 and IL-18 in eosinophil mediated pathogenesis of allergic diseases

Eosinophils are circulating granulocytes that have pleiotropic effects in response to inflammatory signals in the body. In response to allergens or pathogens, exposure eosinophils are recruited in various organs that execute pathological immune responses. IL-5 plays a key role in the differentiation, development, and survival of eosinophils. Eosinophils are involved in a variety of allergic diseases including asthma, dermatitis and various gastrointestinal disorders (EGID). IL-5 signal transduction involves JAK-STAT-p38MAPK-NFκB activation and executes extracellular matrix remodeling, EMT transition and immune responses in allergic diseases. IL-18 is a classical cytokine also involved in immune responses and has a critical role in inflammasome pathway. We recently identified the IL-18 role in the generation, transformation, and maturation of (CD101⁺CD274⁺) pathogenic eosinophils. In, addition, several other cytokines like IL-2, IL-4, IL-13, IL-21, and IL-33 also contribute in advancing eosinophils associated immune responses in innate and adaptive immunity. This review discusses with a major focus (1) Eosinophils and its constituents, (2) Role of IL-5 and IL-18 in eosinophils development, transformation, maturation, signal transduction of IL-5 and IL-18, (3) The role of eosinophils in allergic disorders and (4) The role of several other associated cytokines in promoting eosinophils mediated allergic diseases.     

Th17 cytokines induce pro-fibrotic cytokines release from human eosinophils

Background

Subepithelial fibrosis is one of the most critical structural changes affecting bronchial airway function during asthma. Eosinophils have been shown to contribute to the production of pro-fibrotic cytokines, TGF-β and IL-11, however, the mechanism regulating this process is not fully understood.

Objective

In this report, we investigated whether cytokines associated with inflammation during asthma may induce eosinophils to produce pro-fibrotic cytokines.

Methods

Eosinophils were isolated from peripheral blood of 10 asthmatics and 10 normal control subjects. Eosinophils were stimulated with Th1, Th2 and Th17 cytokines and the production of TGF-β and IL-11 was determined using real time PCR and ELISA assays.

Results

The basal expression levels of eosinophil derived TGF-β and IL-11 cytokines were comparable between asthmatic and healthy individuals. Stimulating eosinophils with Th1 and Th2 cytokines did not induce expression of pro-fibrotic cytokines. However, stimulating eosinophils with Th17 cytokines resulted in the enhancement of TGF-β and IL-11 expression in asthmatic but not healthy individuals. This effect of IL-17 on eosinophils was dependent on p38 MAPK activation as inhibiting the phosphorylation of p38 MAPK, but not other kinases, inhibited IL-17 induced pro-fibrotic cytokine release.

Conclusions

Th17 cytokines might contribute to airway fibrosis during asthma by enhancing production of eosinophil derived pro-fibrotic cytokines. Preventing the release of pro-fibrotic cytokines by blocking the effect of Th17 cytokines on eosinophils may prove to be beneficial in controlling fibrosis for disorders with IL-17 driven inflammation such as allergic and autoimmune diseases.     

C20-trifluoro-5-oxo-ETE: a metabolically stable 5-oxo-ETE derivative

The total synthesis of C₂₀-trifluoro-6(E),8(Z),11(Z),14(Z) 5-oxo-ETE is reported. This compound was designed as an ω-oxidation-resistant analog of 5-oxo-ETE that would be resistant to metabolism. The trifluoro derivative of 5-oxo-ETE stimulated calcium mobilization in neutrophils and desensitized these cells to subsequent exposure to 5-oxo-ETE.