(-)-Epigallocatechin-3-gallate (EGCG) ameliorates ovalbumin-induced asthma by inhibiting inflammation via the TNF-α/TNF-R1/NLRP3 signaling pathway.

(-)-Epigallocatechin-3-gallate (EGCG) is a polyphenol in green tea with potential lung-protective effects. However, the effects of EGCG on airway inflammation in asthma remain unclear. The aim of this study was to investigate the effect and mechanism of EGCG on asthmatic airway inflammation. In this study, the therapeutic effects of EGCG on ovalbumin (OVA)-induced asthmatic mice were tested first. Second, the effects of EGCG on airway inflammation, airway hyperresponsiveness (AHR), airway mucus hypersecretion, cell apoptosis and differential genes were investigated. Finally, the relationships between the effects of EGCG on airway inflammation and the TNF-α/TNF-R1/NLRP3 signaling pathway in asthmatic mice were explored. The results showed that EGCG could attenuate AHR, alleviate the symptoms of alveolar wall thickening and inflammatory cell infiltration, decrease the levels of inflammatory cytokines and airway mucus markers, reduce apoptosis and reactive oxygen species (ROS) and increase the mitochondrial membrane potential (MMP) in primary lung cells in asthmatic mice. Additionally, EGCG significantly inhibited the activation of the TNF-α/TNF-R1/NLRP3 signaling pathway in the lung tissues of asthmatic mice. The lowest binding free energies of EGCG with TNF-α, TNF-R1 and NLRP3 were -11.6, -11.6 and -8.2 kcal/mol, respectively. Moreover, the equilibrium dissociation constant (KD) of EGCG and TNF-R1was 26.05 μmol/L. EGCG-mediated inhibition of TNF-α/TNF-R1/NLRP3 signaling pathway activation was blocked in LPS-induced BEAS-2B and RAW264.7 cells overexpressing TNF-α. Consequently, EGCG effectively attenuated AHR and inhibited airway inflammation and airway mucus hypersecretion in asthmatic mice, and these effects may be closely related to the TNF-α/TNF-R1/NLRP3 signaling pathway.

Zhang B ，Zeng M ，Tie Q ，Wang R ，Wang M ，Wu Y ，Zheng X ，Feng W ... -  《-》

Silencing TRIM8 alleviates allergic asthma and suppressing Th2 differentiation through inhibiting NF-κB/NLRP3 signaling pathway.

Allergic asthma is a primary type of asthma and characterized by T helper 2 (Th2) cells -mediated inflammation. Tripartite motif containing 8 (TRIM8) protein is involved in immunoreaction and inflammatory response in many diseases. However, its role in allergic asthma remains unclear. Medical databank showed that TRIM8 was increased in lung of ovalbumin (OVA)-challenged mice. This study aimed to elucidate the effects of TRIM8 on allergic asthma and Th2 development. Asthma were induced by OVA challenge in mice, and the adenovirus vector loaded with TRIM8 knockdown sequence was delivered into asthma mice by nasal inhalation. The percentage of Th2 cells in lung was assessed by flow cytometric analysis, and the contents of Th2 cytokines (interleukin (IL)-4, IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF) were assessed with ELISA. In vitro Th2 induction was performed in CD4+ cells from mouse spleen, the expression of Th2 molecules (IL-4, IL-5 and GATA binding protein 3 (GATA3)) were measured by real-time PCR. In addition, the nuclear factor-kappa B (NF-κB)/nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain containing 3 (NLRP3) signaling was determined. TRIM8 was highly expressed in the lung tissues of asthmatic mice and Th2-induced CD4+ cells. OVA challenge-induced Th2 development and Th2 cytokine secretion were restrained by silencing of TRIM8 in vivo. Similarly, the Th2 differentiation in vitro was also suppressed by TRIM8 knockdown. TRIM8 inhibited the NF-κB/NLRP3 activity by blocking transforming growth factor-beta-activated kinase 1 (TAK1), and the effects of TRIM8 were abrogated by overexpression of NLRP3. Silencing TRIM8 relieved the asthmatic injury in mice and excessive Th2 development via inhibiting the NF-κB/NLRP3 pathway. It is indicated that TRIM8 may contribute to the airway inflammation in allergic asthma via activating the NF-κB/NLRP3 signaling pathway. The current study provided a novel potential target for allergic asthma treatment.

Tang Y ，Zhao Y ，Guan Y ，Xue L ，Guo J ，Zhao T ，Guan Y ，Tong S ，Che C ... -  《-》

Transforming growth factor-β3/Smad2/Smad3 signaling pathway inhibition and autophagy by the Yunpi-Xiefei-Huatan decoction ameliorated airway inflammation and mucus hypersecretion in asthmatic rats.

The Yunpi-Xiefei-Huatan decoction (YXHD) is a traditional Chinese medicine that can improve asthma-related symptoms, including cough, phlegm in the throat, and shortness of breath. However, the YXHD mechanism on asthma has not yet been elucidated. The aim of this study is to investigate the effect of YXHD on airway inflammation, mucus hypersecretion, and autophagy modulation in asthma. The YXHD chemical constituents were observed and analyzed using high-performance liquid chromatography-mass spectrometry. Ovalbumin sensitization and stimulation were used to establish an asthma rat model. A total of 80 Sprague-Dawley (SD) rats were segmented into eight groups at random: a Normal (NC) group, a Model (Mod) group, a YXHD low-dose group (10 g/kg/d), a YXHD moderate-dose group (20 g/kg/d), a YXHD high-dose group (40 g/kg/d), a Rapamycin group (4 mg/kg/d), a 3-methyladenine (3-MA) group (15 mg/kg/d), and a Dexamethasone (DEX) group (0.5 mg/kg/d). Whole-body plethysmography (WBP) detection was used to evaluate airway hyperresponsiveness. An enzyme-linked immunosorbent assay (ELISA) was used to detect inflammatory factors in the peripheral blood. Inflammatory cells in the bronchoalveolar lavage fluid (BALF) were also counted. Pathological changes in the lung tissues were marked using hematoxylin and eosin (H&E) staining and periodic acid-Schiff (PAS) staining. The localization of MUC5AC and the co-localization of LC3B + MUC5AC were observed using immunofluorescence. The expressions of autophagy and the TGF-β3/Smad2/Smad3 pathway in the lung tissues were detected using a Western blot assay (WB) and qPCR, and the autophagosomes in the lung tissues were detected using a transmission electron microscope (TEM). Twenty signal peaks were identified using ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) technology. The TGF-β3/Smad2/Smad3 signal pathway activation was induced using ovalbumin (OVA) exposure in the rats. The upregulated expression of autophagy, enhanced MUC5AC fluorescence and LC3B fluorescence, and their co-localized expression in the airway epithelium indicated inflammatory cell infiltration and excessive mucus secretion in the lungs. This resulted in airway hyper-responsiveness. The YXHD inhibited the activation of the TGF-β3/Smad2/Smad3 signaling pathway, and autophagy expression reduced inflammatory factors, abnormal mucus secretion, and airway hyperresponsiveness. The YXHD improved lung function, relieved lung inflammation, and inhibited airway mucus secretions in asthmatic rat models. Its mechanism may have been related to the blockage of the TGF-β3/Smad2/Smad3 signaling pathway and autophagy downregulation.

Wang W ，Chen Z ，Cui K ，Chen N ，Gao Q ... -  《-》

Pingchuan formula improve airway remodeling via regulation of the nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3/interleukin-1β and C-Jun N-terminal kinase pathways.

Xu WC ，Lu ZY ，Liu XM ，Wu RF ，Cao L ，Chen LN ，Chen SY ，Yu JE ，Zhuang C ... -  《-》

Luteolin alleviates airway remodeling in asthma by inhibiting the epithelial-mesenchymal transition via β-catenin regulation.

Asthma is a prevalent long-term inflammatory condition that causes airway inflammation and remodeling. Increasing evidence indicates that epithelial-mesenchymal transition (EMT) holds a prominent implication in airway reconstruction in patients with asthma. Flavonoids obtained from Chinese Materia Medica (CMM), such as Luteolin (Lut), exhibit various beneficial effects in various asthma models. Lut has been shown to mitigate various asthma symptoms, including airway inflammation, hyperresponsiveness, bronchoconstriction, excessive mucus production, pulmonary autophagy, and neutrophilic asthma. However, whether flavonoids can suppress EMT-associated airway remodeling in asthma and the fundamental mechanisms involved remain unclear, with no studies specifically addressing Lut in this context. To evaluate the inhibition of airway remodeling in asthma by Lut and its potential mechanisms, while examining the significance of β-catenin in this process through cellular and animal studies. A BEAS-2B cell model stimulated by lipopolysaccharide (LPS) was established in vitro. Wound closure and Transwell assays were utilized to assess the cellular migratory ability. EMT- and fibrosis-related markers in LPS-stimulated cells were evaluated using RT-qPCR and western blotting. The status of the β-catenin/E-cadherin and β-catenin destruction complexes was evaluated using western blotting, immunofluorescence (IF) staining, and co-immunoprecipitation (Co-IP) analysis. The regulatory function of Lut in β-catenin-dependent EMT was further validated by β-catenin overexpression with adenovirus transduction and siRNA-mediated knockdown of β-catenin. Moreover, the counts of different types of bronchoalveolar lavage fluid (BALF) inflammatory cells from mice with asthma induced by ovalbumin (OVA) were evaluated in vivo using Congo red staining. Hematoxylin and eosin (H&E), Masson's trichrome, and periodic acid-Schiff (PAS) staining were used to evaluate collagen deposition, mucus production, and inflammation in murine lung tissues. Western blotting and immunohistochemistry (IHC) assays were used to assess EMT- and fibrosis-related markers in the lung tissues in vivo. Six naturally derived flavonoids, including Lut, attenuated cell migration and prevented EMT in LPS-treated BEAS-2B cells. Moreover, Lut suppressed TGF-β1, MMP-9, fibronectin (FN), and α-smooth muscle actin (α-SMA) levels in LPS-stimulated BEAS-2B cells. Additionally, Lut downregulated the levels of β-catenin by modulating the β-catenin/E-cadherin and β-catenin destruction complexes, highlighting the pivotal role of β-catenin in EMT inhibition by Lut in LPS-stimulated BEAS-2B cells. Furthermore, Lut suppressed airway inflammation and attenuated EMT-associated airway remodeling through β-catenin blockade in OVA-induced asthmatic mice. The bronchial wall thickness notably reduced from 37.24 ± 4.00 μm in the asthmatic model group to 30.06 ± 4.40 μm in the Lut low-dose group and 24.69 ± 2.87 μm in the Lut high-dose group. According to our current understanding, this research is the first to reveal that Lut diminishes airway remodeling in asthma by inhibiting EMT via β-catenin regulation, thereby filling a research gap concerning Lut and flavonoids. These results provide a theoretical basis for treating asthma with anti-asthmatic CMM, as well as a candidate and complementary therapeutic approach to treat asthma.

Quan J ，Xie D ，Li Z ，Yu X ，Liang Z ，Chen Y ，Wu L ，Huang D ，Lin L ，Fan L ... -  《-》