Tumor necrosis factor alpha is necessary for granulocyte-macrophage-colony-stimulating-factor-induced eosinophil transendothelial migration

Epithelial-intrinsic defects in TGFβR signaling drive local allergic inflammation manifesting as eosinophilic esophagitis

Allergic diseases are a global health challenge. Individuals harboring loss-of-function variants in transforming growth factor-β receptor (TGFβR) genes have an increased prevalence of allergic disorders, including eosinophilic esophagitis. Allergic diseases typically localize to mucosal barriers, implicating epithelial dysfunction as a cardinal feature of allergic disease. Here, we describe an essential role for TGFβ in the control of tissue-specific immune homeostasis that provides mechanistic insight into these clinical associations. Mice expressing a TGFβR1 loss-of-function variant identified in atopic patients spontaneously develop disease that clinically, immunologically, histologically, and transcriptionally recapitulates eosinophilic esophagitis. In vivo and in vitro, TGFβR1 variant-expressing epithelial cells are hyperproliferative, fail to differentiate properly, and overexpress innate proinflammatory mediators, which persist in the absence of lymphocytes or external allergens. Together, our results support the concept that TGFβ plays a fundamental, nonredundant, epithelial cell-intrinsic role in controlling tissue-specific allergic inflammation that is independent of its role in adaptive immunity.

Opposing roles of nuclear receptor HNF4α isoforms in colitis and colitis-associated colon cancer

HNF4α has been implicated in colitis and colon cancer in humans but the role of the different HNF4α isoforms expressed from the two different promoters (P1 and P2) active in the colon is not clear. Here, we show that P1-HNF4α is expressed primarily in the differentiated compartment of the mouse colonic crypt and P2-HNF4α in the proliferative compartment. Exon swap mice that express only P1- or only P2-HNF4α have different colonic gene expression profiles, interacting proteins, cellular migration, ion transport and epithelial barrier function. The mice also exhibit altered susceptibilities to experimental colitis (DSS) and colitis-associated colon cancer (AOM+DSS). When P2-HNF4α-only mice (which have elevated levels of the cytokine resistin-like β, RELMβ, and are extremely sensitive to DSS) are crossed with Retnlb(-/-) mice, they are rescued from mortality. Furthermore, P2-HNF4α binds and preferentially activates the RELMβ promoter. In summary, HNF4α isoforms perform non-redundant functions in the colon under conditions of stress, underscoring the importance of tracking them both in colitis and colon cancer.

Construction and delivery of gene therapy vector containing soluble TNFalpha receptor-IgGFc fusion gene for the treatment of allergic rhinitis

Tumor necrosis factor alpha plays primary role in the pathogenesis of inflammatory diseases. TNFalpha is essential for antigen-specific IgE production and for the induction of Th2-type cytokines. The lack of TNFalpha inhibited the development of allergic rhinitis. In this study, the chimeric gene of soluble TNF receptor and IgGFc fragment (sTNFR-IgGFc) was cloned into the EBV-based plasmid pGEG. When the plasmid pGEG.sTNFR-IgGFc was transferred to endothelium cell, a considerable expression of the sTNFR-IgGFc fusion protein was detected. Moreover, the expression product in the supernatant could antagonize the cytolytic activity of TNFalpha on L929 cells. Then the plasmid was delivered into nasal mucosa of allergic rhinitis mice to determine its effect on this animal model. Results showed that symptoms in treated group were improved. Pathological examination showed the numbers of eosinophil, mast cell and IL-5(+) cells in treated groups were reduced compared with placebo group. These data showed that pGEG.sTNFR-IgGFc expression plasmid is potential for the treatment of allergic rhinitis, and suggest that the antagonist of TNFalpha may provide a new approach for the treatment of allergic rhinitis.

Human airway submucosal glands augment eosinophil chemotaxis during rhinovirus infection

BACKGROUND

Asthma exacerbations are frequently associated with rhinovirus (RV) infections. However, the contribution of airway submucosal gland (SMG) to exacerbations of asthma in RV respiratory infection has not been studied.

OBJECTIVE

This study was undertaken to examine whether RV-infected human respiratory SMG cells produce pro-inflammatory cytokines and chemokines for eosinophils, and augment eosinophil transmigration across human airway epithelium.

METHODS

We infected cultured human tracheal SMG cells with RV14, collected culture media at 1, 3, and 5 days after infection, and measured the chemotactic activity for eosinophils in the culture supernatant using a 48-well microchemotaxis chamber and a (51)Cr-labelled eosinophil transmigration assay.

RESULTS

Exposing a confluent human tracheal SMG cell monolayer to RV14 consistently led to infection. Human SMG cells with RV infection secreted soluble factors activating human eosinophil chemotaxis into the culture supernatant in a time-dependent manner, and the culture supernatant significantly augmented the transmigration of (51)Cr-labelled eosinophils through human airway epithelial cell layers from the basal to mucosal side. These effects were completely abolished by a mixture of a monoclonal antibody regulated on activation, normal T cells expressed and secreted (RANTES) and an antibody to granulocyte macrophage-colony stimulating factor (GM-CSF).

CONCLUSION

These results suggest that human respiratory SMG cells may augment eosinophil transmigration across the airway epithelium through the secretion of RANTES and GM-CSF after RV infection, and may contribute to exacerbations of asthma.

Tumour necrosis factor-alpha-induced expression of intercellular adhesion molecule-1 on human eosinophilic leukaemia EoL-1 cells is mediated by the activation of nuclear factor-kappaB pathway

BACKGROUND

Intercellular adhesion molecule-1 (ICAM-1) has been shown to mediate the adhesion and migration of eosinophils to the site of allergic inflammation. However, molecular mechanisms regulating the expression of ICAM-1 in eosinophils are still being elucidated. We investigated the effect of tumour necrosis factor-alpha (TNF-alpha) on ICAM-1 expression of eosinophils.

METHODS

The surface expression of ICAM-1 on a human eosinophilic leukaemic cell line, EoL-1, was assessed by immunocytochemical staining. The phosphorylation of inhibitor kappa B-alpha (IkappaB-alpha) and p38 mitogen-activated protein kinase (MAPK) was detected by Western blot. Nuclear factor kappa-B (NF-kappaB) pathway-related genes were evaluated by the cDNA expression array system, whereas the activity of NF-kappaB was measured by electrophoretic mobility shift assay (EMSA).

RESULTS

TNF-alpha was found to induce the cell surface expression of ICAM-1. A specific proteasome inhibitor N-cbz-Leu-Leu-leucinal (MG-132), but not a p38 MAPK inhibitor (SB 203580), was found to suppress the TNF-alpha-induced expression of ICAM-1 on EoL-1 cells. The gene expressions of ICAM-1, NF-kappaB and IkappaBalpha were up-regulated after the stimulation with TNF-alpha. Further, TNF-alpha was shown to induce IkappaB-alpha phosphorylation and degradation, thereby indicating the activation of NF-kappaB. In EMSA, there was a shifted NF-kappaB band on TNF-alpha-treated cells with or without SB 203580, but no shifted band was observed on MG-132-treated cells.

CONCLUSION

In vitro studies of EoL-1 cells, an eosinophilic leukaemic cell line, confirmed that NF-kappaB plays an important role in the expression of ICAM-1 and recruitment of eosinophils in allergic inflammation.

Effects of inhaled tumour necrosis factor alpha in subjects with mild asthma

BACKGROUND

Inhaled tumour necrosis factor alpha (TNF alpha) has previously been shown to induce airway neutrophilia and increased airway reactivity in normal subjects. It was hypothesised that a similar challenge would increase airway reactivity in those with mild asthma, but that the inflammatory profile may differ.

METHODS

Ten mild asthmatic subjects were recruited on the basis of clinical asthma and either a sensitivity to methacholine within the range defined for asthma or a 20% improvement in forced expiratory volume (FEV(1)) after 200 micro g salbutamol. Subjects inhaled either vehicle control or 60 ng recombinant human (rh)TNF alpha and were studied at baseline, 6, 24, and 48 hours later. Variables included spirometric parameters, methacholine provocative concentration causing a 20% fall in FEV(1) (PC(20)), induced sputum differential cell count, relative sputum level of mRNA of interleukins (IL)-4, IL-5, IL-9, IL-14, IL-15 and TNF alpha, and the exhaled gaseous markers of inflammation, nitric oxide and carbon monoxide.

RESULTS

PC(20) showed an increase in sensitivity after TNF alpha compared with control (p<0.01). The mean percentage of neutrophils increased at 24-48 hours (24 hour control: 1.1 (95% CI 0.4 to 2.7) v 9.2 (95% CI 3.5 to 14.9), p<0.05), and there was also a rise in eosinophils (p=0.05). Relative levels of sputum mRNA suggested a rise in expression of TNF alpha, IL-14, and IL-15, but no change in IL-4 and IL-5. Spirometric parameters and exhaled gases showed no significant change.

CONCLUSION

The increase in airway responsiveness and sputum inflammatory cell influx in response to rhTNF alpha indicates that TNF alpha may contribute to the airway inflammation that characterises asthma.

Migration of eosinophils across endothelial cell monolayers: interactions among IL-5, endothelial-activating cytokines, and C-C chemokines

Eosinophils are the predominant cell type recruited in inflammatory reactions in response to allergen challenge. The mechanisms of selective eosinophil recruitment in allergic reactions are not fully elucidated. In this study, the ability of several C-C chemokines to induce transendothelial migration (TEM) of eosinophils in vitro was assessed. Eotaxin, eotaxin-2, monocyte chemotactic protein (MCP)-4, and RANTES induced eosinophil TEM across unstimulated human umbilical vein endothelial cells (HUVEC) in a concentration-dependent manner with the following rank order of potency: eotaxin approximately eotaxin-2 > MCP-4 approximately RANTES. The maximal response induced by eotaxin or eotaxin-2 exceeded that of RANTES or MCP-4. Preincubation of eosinophils with anti-CCR3 Ab (7B11) completely blocked eosinophil TEM induced by eotaxin, MCP-4, and RANTES. Activation of endothelial cells with IL-1beta or TNF-alpha induced concentration-dependent migration of eosinophils, which was enhanced synergistically in the presence of eotaxin and RANTES. Anti-CCR3 also inhibited eotaxin-induced eosinophil TEM across TNF-alpha-stimulated HUVEC. The ability of eosinophil-active cytokines to potentiate eosinophil TEM was assessed by investigating eotaxin or RANTES-induced eosinophil TEM across resting and IL-1beta-stimulated HUVEC in the presence or absence of IL-5. The results showed synergy between IL-5 and the chemokines but not between IL-5 and the endothelial activator IL-1beta. Our data suggest that eotaxin, eotaxin-2, MCP-4, and RANTES induce eosinophil TEM via CCR3 with varied potency and efficacy. Activation of HUVEC by IL-1beta or TNF-alpha or priming of eosinophils by IL-5 both promote CCR3-dependent migration of eosinophils from the vasculature in conjunction with CCR3-active chemokines.