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 ... -  《-》

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 ... -  《-》

Deletion of BRCC3 ameliorates airway inflammation in asthma by inhibiting the activation of NLRP3 inflammasome.

BRCA1/BRCA2-containing complex subunit 3 (BRCC3) serves as a deubiquitinating enzyme contributing to multiple inflammation-related disorders. However, the role of BRCC3 in modulating airway inflammation in asthma has not been investigated. This study aimed to examine the role of BRCC3 in airway inflammation using a mouse model of asthma induced by ovalbumin (OVA). BRCC3 levels were found to be elevated in mice with asthma. BRCC3 knockout (KO) mice demonstrated a notable improvement in pathological changes, accompanied by reduced levels of inflammatory cell infiltration and inflammatory cytokines, compared to wild-type (WT) mice following OVA challenge. The NLRP3 inflammasome was high activated in asthmatic mice, which was restrained by BRCC3 KO, as companied by a decrease in NLRP3, ASC, cleaved Caspase-1, cleaved Gasdermin D (GSDMD), IL-1β, and IL-18. In vitro studies demonstrated BRCC3 levels increased in airway epithelial cells in response to house dust mite (HDM) stimulation, depending on the dose and duration of exposure. Silencing BRCC3 in airway epithelial cells protected against HDM-induced cell injury and inflammation, along with inhibiting the NLRP3 inflammasome and pyroptosis. Conversely, the overexpression of BRCC3 in airway epithelial cells worsened DM-induced cell injury and inflammation while also enhancing the NLRP3 inflammasome and pyroptosis. Further investigations revealed that silencing BRCC3 increased the ubiquitination of NLRP3, whereas overexpressing BRCC3 decreased it. Pharmacological inhibition of the NLRP3 inflammasome diminished the effects of BRCC3 overexpression on the inflammation and pyroptosis induced by HDM in airway epithelial cells. Overall, these findings underscore the importance of BRCC3 in the pathogenesis of asthma. Deletion of BRCC3 alleviates airway inflammation in asthma by impeding the activation of the NLRP3 inflammasome, thus indicating that BRCC3 could serve as a potential target for asthma therapy.

Wang H ，Chen Y ，Zhang J ，Wang N ，Tian T ... -  《-》

(-)-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 ... -  《-》

Fibroblast growth factor 21 alleviated atopic march by inhibiting the differentiation of type 2 helper T cells.

The blood FGF21 expression has been previously suggested to increase in patients developing atopic dermatitis (AD) and asthma. However, its impact on atopic march is rarely analyzed. The present work focused on investigating the role of Fibroblast Growth Factor 21(FGF21) in atopic march mice and its underlying mechanisms. The models were induced with Diisononyl phthalate (DINP) and OVA in wild-type C57BL/6 and FGF21-/- mice. RAW264.7 cells were induced by LPS with/without FGF21 or KLB-SiRNA for in vitro analyses. The data indicated that there were more severe allergic reactions including IgE levels and the proportion of mast cells in the blood of FGF21-/- mice in relative to WT model mice during the progression from AD to asthma. However, exogenous administration of FGF21 inhibited allergies. In this study, we reported that FGF21 mitigated AD-like lesions and Th1/2 or Th17/Treg cell imbalance in AD mice, and significantly decreased TSLP, IL-33, IL-4, IL-5, IL-13 and IL-17A expression on skin. During the asthma phase, FGF21 improved airway remodeling by downgrading inflammatory factors IL-4, IL-5, IL-13 and IL-17A; fibrotic markers α-SMA and Collagen I; and oxidative products MDA and ROS in wild-type model mice. Compared with WT model mice, the adverse consequences were aggravated in FGF21-/- asthmatic mice. From the mechanistic perspective, FGF21 suppressed NF-κB/NLRP3, TGF-β1/Smad3 and JNK signaling pathways and increased Nrf2 expression in vivo and in vitro. In addition, β-Klotho knockdown attenuated the ameliorative impact of FGF21 on cellular damage. Blocking AMPKα in the LPS-treated RAW264.7 cells inhibited the reduction of FGF21 and the phosphorylation of JNK. To conclude, FGF21 alleviated atopic march by inhibiting Th2/17 immune response, and reduced airway remodeling by regulating NF-κB/NLRP3, TGF-β1/Smad3 and AMPKα/JNK pathways. Moreover, this study provides a rationale and novel ideas for applying FGF21 in treating AD and asthma.

Wang D ，Zou Y ，Zhao T ，Cao W ，Han J ，Wu Q ，Li Z ，Li X ，Liu P ，Bai L ，Ren G ... -  《-》