From bedside to bench to clinic trials: identifying new treatments for severe asthma

C-Kit+ cells can modulate asthmatic condition via differentiation into pneumocyte-like cells and alteration of inflammatory responses via ERK/NF-ƙB pathway

Objectives

The exact role of the progenitor cell types in the dynamic healing of asthmatic lungs is lacking. This investigation was proposed to evaluate the effect of intratracheally administered rat bone marrow-derived c-kit⁺ cells on ovalbumin-induced sensitized male rats.

Materials and Methods

Forty rats were randomly divided into 4 groups; healthy rats received phosphate-buffered saline (PBS) (C); sensitized rats received PBS (S); PBS containing C-kit- cells (S+C-kit^-); and PBS containing C-kit⁺ cells (S+C-kit⁺). After two weeks, circulatory CD4⁺/CD8⁺ T-cell counts and pulmonary ERK/NF-ƙB signaling pathway as well as the probability of cellular differentiation were assessed.

Results

The results showed that transplanted C-Kit⁺ cells were engrafted into pulmonary tissue and differentiated into epithelial cells. C-Kit⁺ cells could increase the number of CD4⁺ cells in comparison with the S group (P<0.001); however, they diminished the level of CD8⁺ cells (P<0.01). Moreover, data demonstrated increased p-ERK/ERK ratio (P<0.001) and NF-ƙB level (P<0.05) in sensitized rats compared with the C group. The administration of C-kit⁺, but not C-Kit^-, decreased p-ERK/ERK ratio and NF-ƙB level compared with those of the S group (P<0.05).

Conclusion

The study revealed that C-Kit⁺ cells engrafted into pulmonary tissue reduced the NF-ƙB protein level and diminished p-ERK/ERK ratio, leading to suppression of inflammatory response in asthmatic lungs.

Saururus chinensis-controlled allergic pulmonary disease through NF-κB/COX-2 and PGE2 pathways

Saururus chinensis is a perennial herb found in the northeastern regions of Asia, including Korea, China, and Japan, and is used in traditional medicine. Studies have identified the four major constituents in Saururus chinensis water extract (LHF618^®) as miquelianin (11.75 ± 0.092 mg/g), rutin (1.20 ± 0.008 mg/g), quercitrin (2.38 ± 0.389 mg/g), and quercetin (0.068 ± 0.017 mg/g). Saururus chinensis can improve the symptoms of ovalbumin- or fine dust-induced allergic pulmonary disease by suppressing the effects of WBCs and neutrophils in BALF and IgE in the serum. Saururus chinensis dose-dependently recovered morphological changes such as mucous hyper secretion (from 2.7 ± 0.46 to 0.6 ± 0.65), pulmonary epithelial cell hyperplasia (from 2.4 ± 0.55 to 0.7 ± 0.67), and inflammatory cell infiltration (from 2.3 ± 0.45 to 0.6 ± 0.43), and effectively controlled cDNA levels and protein levels of IL-13. It inhibited NF-κB translocation and COX-2 protein synthesis and suppressed the expression of PGE₂. Our results show that Saururus chinensis controlled allergic pulmonary disease via the anti-inflammatory pathways, NF-κB/COX-2 and PGE₂. Saururus chinensis may be a promising drug candidate against fine dust-induced allergic pulmonary disease.

The Value of Targeting Complement Components in Asthma

Asthma is an important respiratory illness. Though pharmacological and biological treatment is well established and is staged according to endotypes and their responses to treatment, novel avenues are being explored. Our focus is complement. In this viewpoint, we evaluate the approach to target complement in this complex hypersensitivity reaction that develops chronicity and has a personal—as well as a societal—cost.

HMGB1-induced ILC2s activate dendritic cells by producing IL-9 in asthmatic mouse model

Asthma is a disease of the respiratory system that is commonly considered a T-helper 2 (Th2) cell-associated inflammatory disease. Group 2 innate lymphoid cells (ILC2s) promote the inflammatory responses in asthma by secreting type 2 cytokines. Interleukin (IL)-9 also serves as a promoting factor in asthma and it is well known that ILC2s have an autocrine effect of IL-9 to sustain their survival and proliferation. However, the specific role of ILC2-derived IL-9 in asthma remains unclear. HMGB1 (High-Mobility Group Box-1) is a nuclear protein, and Previous studies have shown that HMGB1 can regulate the differentiation of T-helper cells and participate in the development of asthma. But whether HMGB1 can regulate the innate lymphocytes in the pathological process of asthma is unknown. In this study we have shown increased presence of HMGB1 protein in the lung of mice with asthma, which was associated with increased secretion of IL-9 by ILC2s. This led to the activation of dendritic cells (DCs) that can accelerate the differentiation of Th2 cells and worsen the severity of asthma. Taken together, our study provides a complementary understanding of the asthma development and highlights a novel inflammatory pathway in the pathogenesis of asthma.

Allium hookeri root extract regulates asthmatic changes through immunological modulation of Th1/Th2‑related factors in an ovalbumin‑induced asthma mouse model

In 2013, WHO estimated that approximately 235 million people suffered from asthma worldwide. Asthma is a hyper responsive disorder, which is related to an imbalance between the T-helper type 1 and 2 cells (henceforth, Th1 and Th2, respectively). Allium hookeri is a plant that is widely used for culinary purposes and also in traditional Asian medicine. The present study was conducted to elucidate the anti-asthmatic effects and mechanism of action of A. hookeri root extracts (AHRE) in an ovalbumin (OVA)-induced asthma mouse model. The mice were divided into five groups, namely, the control, the OVA-treated group, the dexamethasone-treated group, the 30 mg/kg AHRE-treated group, and the 300 mg/kg AHRE-treated group. The total WBC count and the differential cell count in the bronchoalveolar fluid, the level of serum IgE, the histopathological changes in the lung, and changes in the cell surface molecules, the asthma-related cytokine levels, and Th cell transcription factors were evaluated. AHRE significantly ameliorated asthmatic changes, such as the total WBC count, eosinophil count, and the level of IgE; in addition, it reduced mucus hypersecretion, epithelial hyperplasia, and eosinophil infiltration in the lungs. AHRE significantly inhibited the expression of CD68⁺ cells and MHC class II⁺ molecules, Th1 cell transcription factor (T-bet) activation, Th2 cell transcription factor (GATA-3) activation, and TNF-α in the lung tissue. Furthermore, it suppressed cell surface molecules, such as CD4⁺and CD8⁺; Th1-related cytokines, such as IFN-γ and IL-12p40; Th2-related cytokines, such as IL-4 and IL-5; and Th17-related cytokines, such as IL-6 and TNF-α, in a dose-dependent manner. Thus, AHRE may be considered a promising anti-asthmatic drug.

Camellia japonica oil suppressed asthma occurrence via GATA-3 & IL-4 pathway and its effective and major component is oleic acid

BACKGROUND

In December 2016, WHO released a report stating that in 2015 there were 383,000 deaths caused by asthma and 235 million people suffering from asthma. As there are many adverse effects associated with the currently-used asthma drugs, new anti-asthmatic drugs need to be developed.

PURPOSE

In order to find new drug candidates with safe and low side effects, the anti-asthmatic function and mechanism of C. japonica oil were evaluated, and its active ingredients were analyzed for use in an ovalbumin asthma murine model.

STUDY DESIGN AND METHODS

The study consisted of six groups: control; ovalbumin group; and dexamethasone group as a positive control; and 10, 100, and 500 mg/kg C. japonica oil treatment groups. In order to measure the anti-asthmatic effect of C. japonica oil, WBC and differential cell count in BALF, IgE in serum, morphological changes in pulmonary system, and gene and protein levels such as IFN-γ, IL-12p40, IL-4, IL-5, IL-6, TNF-α, and IL-6 were all evaluated.

RESULTS

C. japonica oil had an anti-asthmatic effect and significantly controlled eosinophil in BALF, Th2-related factors such as GATA-3 that is Th2 cell transcription factor, IL-4, IL-5, and IL-13, and TNF-α in the lung. It also dose-dependently modulated inflammatory cells, T-bet, IL-12p40, and IL-6. Oleci acid was the major gradient (52.89%) in C. japonica oil and also had anti-asthmatic effects such as the downregulation of inflammatory cells, WBC, and eosinophil in BALF, IgE in serum, and morphological changes in the lung.

CONCLUSION

We concluded that C. japonica oil is a new anti-asthmatic drug candidate and that oleic acid is the major anti-asthmatic ingredient in C. japonica oil.

Mouse models of severe asthma for evaluation of therapeutic cytokine targeting

Severe asthma is a heterogeneous inflammatory disease of the airways, which requires treatment with high-dose inhaled corticosteroids or their systemic administration, yet often remains uncontrolled despite this therapy. Over the past decades, research efforts into phenotyping of severe asthma and defining the pathological mechanisms of this disease were successful largely due to the development of appropriate animal models. Recent identification of distinct inflammatory patterns of severe asthma endotypes led to novel treatment approaches, including targeting specific cytokines or their receptors with neutralizing antibodies. Here we discuss how different experimental mouse models contributed to generation of clinically relevant findings concerning pathogenesis of severe asthma and to identification of potential targets for biologic therapy.

Metabolic Plasticity in Dendritic Cell Responses: Implications in Allergic Asthma

Dendritic cells (DCs) are highly specialized in antigen presentation and play a pivotal role in the initiation, progression, and perpetuation of adaptive immune responses. Emerging immune pathways are being recognized increasingly for DCs and their subsets that differentially regulate T lymphocyte function based on the type and interactions with the antigen. However, these interactions not only alter the signaling process and DC function but also render metabolic plasticity. The current review focuses on the metabolic cues of DCs that coordinate DC activation and differentiation and discuss whether targeting these fundamental cellular processes have implications to control airway inflammation and adaptive immunity. Therefore, strategies using metabolism-based therapeutic manipulation of DC functions could be developed into novel treatments for airway inflammation and asthma.

Respiratory Syncytial Virus Exacerbates OVA-mediated asthma in mice through C5a-C5aR regulating CD4+T cells Immune Responses

Asthma exacerbation could be induced by respiratory syncytial virus (RSV), and the underlying pathogenic mechanism is related to complement activation. Although complement might regulate CD4⁺T cells immune responses in asthma model, this regulation existed in RSV-induced asthma model remains incompletely characterrized. In this study, we assessed the contribution of C5a-C5aR to CD4⁺T cell immune responses in RSV-infected asthma mice. Female BALB/C mice were sensitized and challenged with ovalbumin (OVA) while treated with RSV infection and C5a receptor antagonist (C5aRA) during challenge period. RSV enhanced lung damage, airway hyperresponsiveness, and C5aR expressions in asthma mice, while C5aRA alleviated these pathologic changes. The percentages of Th1, Th2 and Th17 cells were increased, while the percentage of Treg cells was decreased in RSV-infected asthma mice compared with asthma mice. IFN-γ, IL-4, IL-10 and IL-17A levels have similar trend with Th1, Th2, Th17 and Treg cells. Notably, above changes of CD4⁺T cells and their related cytokines were reversed by C5aRA. Together, the data indicates that RSV infection could apparently increase C5a and C5aR expression in the pathogenesis of RSV-infected asthma mice, meanwhile C5aRA prevents some of the CD4⁺T cells immune changes that are induced by RSV.

Anti-HMGB1 neutralizing antibody ameliorates neutrophilic airway inflammation by suppressing dendritic cell-mediated Th17 polarization

We demonstrate that high mobility group box 1 protein (HMGB1) directs Th17 skewing by regulating dendritic cell (DC) function. First, our in vitro studies reveal that recombinant HMGB1 (rHMGB1) activates myeloid DCs to produce IL-23 in vitro, and rHMGB1-activated DCs prime naïve lymphocytes to produce the Th17 cytokine IL-17A. Second, we demonstrate that anti-HMGB1 neutralizing antibody attenuates HMGB1 expression, neutrophilic inflammation, airway hyperresponsiveness, and Th17-related cytokine secretion in vivo by using a murine model of neutrophilic asthma induced by ovalbumin (OVA) plus lipopolysaccharide (LPS). Furthermore, anti-HMGB1 neutralizing antibody decreases the number of Th17 cells in lung cells and suppresses the production of IL-23 by lung CD11C⁺ APCs. Finally, we show that intranasal adoptive transfer of rHMGB1-activated DCs was sufficient to restore lung neutrophilic inflammation and the Th17 response in a DC-driven model of asthma, whereas the transfer of rHMGB1 plus anti-HMGB1-treated mDCs significantly reduced these inflammation phenotypes. These data suggest, for the first time, that HMGB1 drives the DC-polarized Th17-type response in allergic lung inflammation and that blocking HMGB1 may benefit the attenuation of neutrophilic airway inflammation in asthma.