Iristectorigenin A exerts novel protective properties against airway inflammation and mucus hypersecretion in OVA-induced asthmatic mice: Iristectorigenin A ameliorates asthma phenotype.

BACKGROUND: Despite the substantial amount of efforts made to reduce morbidity and improve respiratory management, asthma control remained a major challenge for severe patients. Plant isoflavones, one of the most estrogenic compounds, are considered a potential alternative therapy for asthma. Iristectorigenin A, a naturally occurring isoflavone, is extracted from a variety of medical plants and its biological activity has not been reported previously. PURPOSE: In present study, we aim to reveal the potential therapeutic role of Iristectorigenin A against acute asthmatic mice. STUDY DESIGN: We established ovalbumin (OVA) induced asthmatic murine model and orally administrated Iristectorigenin A at concentration of 5 and 10 mg/kg and dexamethasone as a positive control substance. METHODS: Asthmatic murine model was established with OVA sensitization and challenge. Lung function was assessed with FinePoint Ventilation system recording lung resistance (RI) and lung compliance (Cydn). White cells were sorted and counted in BALF. Histopathological assessment was conducted by H&E, PAS, and Masson's trichrome staining on paraffin embedded lung tissues. BALF content of IL-4, IL-5, IL-33, IL-13, INF-γ, IL-9 and serum IgE, IgG1 were measured using ELISA kit. Expression levels of mRNAs associated with inflammatory cytokines and goblet cell metaplasia were evaluated via quantitative RT-PCR. Protein expression levels of FOXA3, MUC5AC, SPDEF were estimated by immunohistochemistry on lung tissue, while NOTCH1 and NOTCH2 expressions were evaluated by western blotting analysis. RESULTS: Iristectorigenin A resulted in improved airway hyperresponsiveness (AHR) mirrored by decreased RI and increased Cydn. With Iristectorigenin A, we also observed reduced number of BALF leukocytes, improved inflammatory cell infiltration in lung tissue, decreased content of BALF IL-4, IL-5, IL-33, but not IL-13, INF-γ, IL-9, and their mRNA levels, along with decreased levels of OVA-specific IgE, IgG1 in asthmatic mice. Additionally, Iristectorigenin A exhibited significant therapeutic potential on attenuating mucus production reflected by mitigated FOXA3 and MUC5AC immunostaining on the airway epithelium, as well as decreased mRNAs associated with goblet cell metaplasia. At last, a decrease in elevated expression level of NOTCH2, but not NOTCH1, in asthmatic mice lung tissue was observed by western blotting analysis. CONCLUSION: Our study provides strong evidence that Iristectorigenin A can be potential therapeutic agent ameliorating airway inflammation and mucus hypersecretion in allergic asthma. This is a first research reported the potential of Iristectorigenin A as an alternative therapeutic agent.

N6-Methyladenosine Methylomic Landscape of Lung Tissues in Murine Acute Allergic Asthma.

Allergic asthma is well known as a common respiratory disorder comprising an allergic inflammatory nature and excessive immune characteristic. N6-methyladenosine (m6A) methylation is an RNA epigenetic modification that post-transcriptionally regulates gene expression and function by affecting the RNA fate. Currently, m6A methylation is gaining attention as a mechanism of immunoregulation. However, whether m6A methylation engages the pathological process of asthma remains uncertain. Here, we present the m6A methylomic landscape in the lung tissues of ovalbumin-induced acute asthma mice using MeRIP-seq and RNA-seq. We identified 353 hypermethylated m6A peaks within 329 messenger RNAs (mRNAs) and 150 hypomethylated m6A peaks within 143 mRNAs in the lung tissues of asthmatic mice. These differentially methylated mRNAs were found to be involved in several immune function-relevant signaling pathways. In addition, we predicted 25 RNA-binding proteins that recognize the differentially methylated peak sites by exploring public databases, and the roles of these proteins are mostly related to mRNA biogenesis and metabolism. To further investigate the expression levels of the differentially methylated genes, we performed combined analysis of the m6A methylome and transcriptome data and identified 127 hypermethylated mRNAs (107 high and 20 low expression) and 43 hypomethylated mRNAs with differential expressions (9 high and 34 low expression). Of these, there are a list of mRNAs involved in immune function and regulation. The present results highlight the essential role of m6A methylation in the pathogenesis of asthma.

Luteolin inhibits autophagy in allergic asthma by activating PI3K/Akt/mTOR signaling and inhibiting Beclin-1-PI3KC3 complex.

Allergic asthma is a common chronic inflammatory disease characterized by airway inflammation, mucus hypersecretion and airway remodeling. Autophagy is a highly conserved intracellular degradation pathway in eukaryotic cells. There is growing evidence suggesting that dysregulation of autophagy is involved in the pathological process of asthma. Luteolin is a typical flavonoid compound with anti-inflammatory, anti-allergic and immune-enhancing functions. Previous studies have shown that luteolin can attenuate airway inflammation and hypersensitivity in asthma. However, whether luteolin can play a role in treating asthma by regulating autophagy remains unclear. The aim of the present study was to evaluate the therapeutic effect of luteolin on ovalbumin (OVA)-induced asthmatic mice, observe its effect on the level of autophagy in lung tissues, and further elucidate its underlying mechanism. The results showed that OVA-induced mice developed airway hyperresponsiveness, mucus over-production and collagen deposition. The number of inflammatory cells, levels of interleukin (IL)-4, IL-5 and IL-13 in bronchoalveolar lavage fluid (BALF) and OVA-specific IgE in serum were significantly increased. Furthermore, the infiltration of inflammatory cells was observed along with the activation of autophagy in lung tissues. Luteolin treatment significantly inhibited the OVA-induced inflammatory responses and the level of autophagy in lung tissues as well. Moreover, luteolin activated the PI3K/Akt/mTOR pathway and inhibited the Beclin-1-PI3KC3 protein complex in lung tissues of asthmatic mice. In conclusion, this study explored the regulatory mechanism of luteolin on autophagy in allergic asthma, providing biologic evidence for its clinical application.

TMT-based quantitative proteomics reveals suppression of SLC3A2 and ATP1A3 expression contributes to the inhibitory role of acupuncture on airway inflammation in an OVA-induced mouse asthma model.

Asthma is a chronic airway inflammatory disease and acupuncture is frequently used in patients suffering from asthma in clinic. However, the regulatory mechanism of acupuncture treatment in asthma is not fully elucidated. We sought to investigate the effectiveness of acupuncture on asthma and the associated regulatory mechanism. An ovalbumin (OVA)-induced mouse asthma model was established and the effect of acupuncture on airway hyperresponsiveness (AHR), mucus hypersecretion and inflammation was assessed. Tandem mass tag (TMT)-based quantitative proteomics analysis of lung tissue and bioinformatics analysis were performed. Our results revealed that the OVA-induced mouse asthma model was successfully established with the significantly elevated AHR to methacholine (Mch), and acupuncture was effective in attenuation of AHR to Mch, peribronchial and perivascular inflammation and mucus production. The inflammatory cells around the airways, mucous secretion as well as levels of IgE, CCL5, CCL11, IL-17A in bronchoalveolar lavage fluid (BALF) and IL-4, IL-5 and IL-13 levels in serum were siginificantly inhibited by acupuncture. TMT-based quantitative proteomics analysis found that a total of 6078 quantifiable proteins were identified, and 564 (334 up-regulated and 230 down regulated) differentially expressed proteins (DEPs) were identified in OVA-induced asthma model group (A) versus normal control group (NC). Acupuncture treatment resulted in 667 DEPs (416 up-regulated and 251 down regulated) compared with A group, and 86 overlapping DEPs were identified in NC, A and AA groups. Among the 86 overlapping DEPs, we identified 41 DEPs regulated by acupuncture. Based on the above data, we performed a systematic bioinformatics analysis of the 41 DEPs, and results showed that these 41 DEPs were predominantly related to 4 KEGG pathways including SNARE interactions in vesicular transport, ferroptosis, endocrine and other factor-regulated calcium reabsorption, and protein digestion and absorption. DEPs of SLC3A2 and ATP1A3 expression levels were verified by immumohistochemical staining. Mice in OVA-induced asthma model group had elevated SLC3A2 and ATP1A3 expression and acupuncture had the ability to downregulate SLC3A2 and ATP1A3 protein expression. Furthermore, acupuncture reduced the MDA level and increased the GSH and SOD levels in the lung tissue. Taken together, our data suggested that acupuncture was effective in treating asthma by attenuation of AHR, mucus secretion and airway inflammation, and the mechanism was associated with regulation of ferroptosis, SLC3A2 and ATP1A3 protein expression as well as oxidative stress. Results from our experiments revealed the anti-inflammatory effect of acupuncture in OVA-induced mouse asthma model, leading to a more effective approach to be chosen by patients in clinic.