TNFSF11/TNFRSF11A Axis Amplifies HDM-Induced Airway Remodeling by Strengthening TGFß1/STAT3 Action.

PURPOSE: Asthma, an airway inflammatory disease, involves multiple tumor necrosis factors (TNF). TNF ligand superfamily member 11 (TNFSF11) and its known receptor, TNF receptor superfamily 11A (TNFRSF11A), has been implicated in asthma; however, the related mechanisms remain unknown. METHODS: The serum and bronchial airway of patients with asthma and healthy subjects were examined. The air-liquid interface of primary human bronchial epithelial (HBE) cells, and Tnfsf11+/- mouse, Tnfrsf11a+/- mouse, and a humanized HSC-NOG-EXL mouse model were established. This study constructed short hairpin RNA (shRNA) of TNFSF11, TNFRSF11A, transforming growth factor ß1 (TGFß1), and transforming growth factor ß receptor type 1 (TGFßR1) using lentivirus to further examine the ability of TNFSF11 protein. RESULTS: This study was the first to uncover TNFSF11 overexpression in the airway and serum of asthmatic human subjects, and the TNFSF11 in serum was closely correlated with lung function. The TNFSF11/TNFRSF11A axis deficiency in Tnfsf11+/- or Tnfrsf11a+/- mice remarkably attenuated the house dust mite (HDM)-induced signal transducer and activator of transcription 3 (STAT3) action and remodeling protein expression. Similarly, the HDM-induced STAT3 action and remodeling protein expression in HBE cells decreased after pretreatment with TNFSF11 or TNFRSF11A shRNA. Meanwhile, the expression of the remodeling proteins induced by TNFSF11 significantly decreased after pretreatment with-stattic (inhibitor of STAT3 phosphorylation) in HBE cells. The STAT3 phosphorylation and remodeling protein expression induced by TNFSF11 obviously decreased after pretreatment with TGFß1 or TGFßR1 shRNA in HBE cells. The above results also verified that blocking TNFSF11 with denosumab alleviated airway remodeling via the TGFß1/STAT3 signaling in the humanized HSC-NOG-EXL mice with HDM-induced asthma. CONCLUSIONS: TGFß1/STAT3 action was closely correlated with TNFSF11/TNFRSF11A axis-mediated airway remodeling. This study presented a novel strategy that blocks the TNFSF11/TNFRSF11A axis to exert a protective effect against asthma.

LincR-PPP2R5C Deficiency Alleviates Airway Remodeling by Inhibiting Epithelial-Mesenchymal Transition Through the PP2A/TGF-ß1 Signaling Pathway in Chronic Experimental Allergic Asthma.

Airway remodeling is a key characteristic of allergic asthma. Epithelial-mesenchymal transition (EMT) induced by various factors, particularly transforming growth factor (TGF)-ß1, orchestrates airway remodeling. Protein phosphatase 2A (PP2A), an important serine-threonine phosphatase, is involved in TGF-ß1 production and EMT. Long noncoding RNAs (lncRNAs) have emerged as novel players in regulating EMT. Here, we aimed to explore the effects and mechanisms of action of lincR-PPP2R5C, a lncRNA that affects PP2A activity, on airway remodeling in a mouse model of chronic allergic asthma. LincR-PPP2R5C knockout (KO) alleviated inflammatory responses in house dust mite (HDM)-induced chronic allergic asthma. Moreover, airway remodeling and EMT were reduced in lung tissues of lincR-PPP2R5C KO mice. HDM extract induced EMT in airway epithelial cells, which was decreased following lincR-PPP2R5C KO. Mechanistically, lincR-PPP2R5C deficiency enhanced PP2A activity, which inhibited TGF-ß1 production in epithelial cells. In conclusion, lincR-PPP2R5C deficiency prevented HDM-induced airway remodeling in mice by reversing EMT, which was mediated by the PP2A/TGF-ß1 signaling pathway. Thus, lncRNAs, i.e., lincR-PPP2R5C, may be potential targets to prevent airway remodeling in allergic asthma.

Piezo Channels Modulate Human Lung Fibroblast Function.

Bronchial airways and lung parenchyma undergo both static and dynamic stretch in response to normal breathing but also in the context of insults such as mechanical ventilation (MV) or in diseases such as asthma and COPD which lead to airway remodeling involving increased extracellular matrix (ECM) production. Here, the role of fibroblasts is critical, but the relationship between stretch and fibroblast induced ECM remodeling under these conditions is not well-explored. Piezo (PZ) channels play a role in mechanotransduction in many cell and organ systems, but their role in mechanical stretch-induced airway remodeling is not known. To explore this, we exposed human lung fibroblasts to 10% static stretch on a background of 5% oscillations for 48 hours, with no static stretch considered controls. Collagen I, Fibronectin, α-SMA, and Piezo 1 (PZ1) expression were determined in the presence or absence of Yoda1 (PZ1 agonist) or GsMTx4 (PZ1 inhibitor). Collagen I, Fibronectin, and α-SMA expression was increased by stretch and Yoda1 while pretreatment with GsMTx4 or knockdown of PZ1 by siRNA blunted this effect. Acute stretch in the presence and absence of Yoda1 demonstrated activation of ERK pathway but not Smad. Measurement of [Ca2+] i responses to histamine showed significantly greater responses following stretch: effects that were blunted by knockdown of PZ1.Our findings identify an essential role for PZ1 in mechanical stretch-induced production of ECM mediated by ERK phosphorylation and Ca2+ influx in lung fibroblasts. Targeting PZ channels in fibroblasts may constitute a novel approach to ameliorate airway remodeling by decreasing ECM deposition.

Mechanism of cigarette smoke in promoting small airway remodeling in mice via STAT 3 / PINK 1-Parkin / EMT.

BACKGROUND: Airway remodeling is an important pathological of airflow limitation in chronic obstructive pulmonary disease (COPD).However,its mechanism still needs to be further clarify. METHODS: Animals:Healthy male C57BL/6 mice aged 4-6 weeks were randomly divided into control group and cigarette smoke(CS)group. Mice in the CS group were placed in a homemade glass fumigator, 5 cigarettes/time, 40 min/time, 4 times/day, 5 days/week, for 24 weeks. Mice in the control group were placed in a normal air environment.Cells:BEAS-2B cells were stimulated with 0.1%cigarette smoke extract(CSE).HE staining,immunohistochemical staining and Masson staining were used to observe the pathological of lung tissues,transmission electron microscopy was used to observe the structural of mitochondria in bronchial epithelial cells.Western blotting was used to detect the expression of STAT3,transforming growth factor-ß1(TGF-ß1),microtubule-associated protein 1A/1B-light chain3(LC3),PINK1,Parkin,E-cadherin,zonula occludens1(ZO-1),vimentin and snail family transcriptional inhibitor1 (Snail1),and MitoSOX Red was used to detect mitochondrial reactive oxygen species(mtROS). RESULTS: CS exposure causes lung parenchymal destruction and airway remodeling in mice.Compared to the control group,the expression of p-STAT3,TGF-ß1 and EMT in the whole lung homogenate of the CS group was increased.Mitochondrial architecture disruption in bronchial epithelial cells of CS mice,with impaired PINK1-Parkin-dependent mitophagy.In vitro experiments showed that CSE exposure led to STAT3 activation,increased TGF-ß1,EMT and enhanced PINK1-Parkin-mediated mitophagy.STAT3 inhibition reversed TGF-ß1 upregulation induced by CSE and improved CSE-induced EMT and mitophagy.Inhibition of mitophagy improves EMT induced by CSE. Inhibition of mitophagy reduces STAT3-induced EMT. CONCLUSION: CS activates the STAT3,and activated STAT3 promotes EMT in bronchial epithelial cells by enhancing PINK1-Parkin-mediated mitophagy and TGF-ß1 signaling.Moreover,activated STAT3 can promote EMT directly.This may be one of the mechanisms by which CS causes small airway remodeling in COPD.

SMAD4 promotes EMT in COPD airway remodeling induced by cigarette smoke through interaction with O-GlcNAc transferase.

Cigarette smoke (CS) is a prevalent chemical indoor air contaminant known to be the primary cause of EMT during airway remodeling in COPD. While some evidence indicates the involvement of SMAD4 in EMT across certain diseases, its specific role in CS-induced EMT in airway remodeling associated with COPD is not established. In our research, we observed a substantial upregulation in SMAD4 expression, O-GlcNAcylation and EMT in patients with COPD, as well as in vitro and in vivo COPD models induced by CS, than those of the controls. Downregulation of SMAD4 resulted in a reduction in CS-induced EMT in vitro and in vivo. As a post-translational modification of proteins, O-GlcNAcylation is dynamically controlled by the duo of enzymes: O-linked N-acetylglucosamine (O-GlcNAc) transferase (OGT) and O-GlcNAcase (OGA). We further discovered the enhancement of O-GlcNAcylation levels induced by CS was due to an elevated OGT expression, as the expression of OGA remained unchanged. Using an OGT inhibitor (OSMI-1) counteracted the effects of SMAD4 on EMT. Whereas, overexpressing OGT increased SMAD4 expression and promoted EMT. OGT-mediated SMAD4 O-GlcNAcylation shielded SMAD4 from proteasomal degradation by reducing its ubiquitination, thereby aiding in SMAD4 stabilization in response to EMT induced by CS. Overall, this research uncovers a fresh pathway for CS-induced EMT in the airway remodeling of COPD and offers valuable insights.

G12/13 signaling in asthma.

Shortening of airway smooth muscle and bronchoconstriction are pathognomonic for asthma. Airway shortening occurs through calcium-dependent activation of myosin light chain kinase, and RhoA-dependent calcium sensitization, which inhibits myosin light chain phosphatase. The mechanism through which pro-contractile stimuli activate calcium sensitization is poorly understood. Our review of the literature suggests that pro-contractile G protein coupled receptors likely signal through G12/13 to activate RhoA and mediate calcium sensitization. This hypothesis is consistent with the effects of pro-contractile agonists on RhoA and Rho kinase activation, actin polymerization and myosin light chain phosphorylation. Recognizing the likely role of G12/13 signaling in the pathophysiology of asthma rationalizes the effects of pro-contractile stimuli on airway hyperresponsiveness, immune activation and airway remodeling, and suggests new approaches for asthma treatment.

The Role of Transforming Growth Factor-ß (TGF-ß) in Asthma and Chronic Obstructive Pulmonary Disease (COPD).

Asthma and chronic obstructive pulmonary disease (COPD) represent chronic inflammatory respiratory disorders that, despite having distinct pathophysiological underpinnings, both feature airflow obstruction and respiratory symptoms. A critical component in the pathogenesis of each condition is the transforming growth factor-ß (TGF-ß), a multifunctional cytokine that exerts varying influences across these diseases. In asthma, TGF-ß is significantly involved in airway remodeling, a key aspect marked by subepithelial fibrosis, hypertrophy of the smooth muscle, enhanced mucus production, and suppression of emphysema development. The cytokine facilitates collagen deposition and the proliferation of fibroblasts, which are crucial in the structural modifications within the airways. In contrast, the role of TGF-ß in COPD is more ambiguous. It initially acts as a protective agent, fostering tissue repair and curbing inflammation. However, prolonged exposure to environmental factors such as cigarette smoke causes TGF-ß signaling malfunction. Such dysregulation leads to abnormal tissue remodeling, marked by excessive collagen deposition, enlargement of airspaces, and, thus, accelerated development of emphysema. Additionally, TGF-ß facilitates the epithelial-to-mesenchymal transition (EMT), a process contributing to the phenotypic alterations observed in COPD. A thorough comprehension of the multifaceted role of TGF-ß in asthma and COPD is imperative for elaborating precise therapeutic interventions. We review several promising approaches that alter TGF-ß signaling. Nevertheless, additional studies are essential to delineate further the specific mechanisms of TGF-ß dysregulation and its potential therapeutic impacts in these chronic respiratory diseases.

Shegan-Mahuang decoction ameliorates cold-induced asthma via regulating the proliferation and apoptosis of airway smooth muscle cells through TAS2R10: An in vivo and in vitro study.

ETHNOPHARMACOLOGICAL RELEVANCE: Shegan-Mahuang Decoction (SMD) is a classical formula that has been used to effectively treat cold-induced asthma (CA) for 1800 years. Airway smooth muscle cells (ASMCs) play a crucial role in airway remodeling of CA and can be modulated through bitter taste-sensing type 2 receptors (TAS2Rs). Given that SMD contains numerous bitter herbs and TAS2R10 expression in ASMCs remains consistently high, it is pertinent to explore whether SMD regulates ASMCs via TAS2R10 to exert its CA mechanism. AIM OF THE STUDY: This study investigated the efficacy as well as the potential mechanism of SMD in CA. MATERIALS AND METHODS: In this study, experiments in vivo were conducted using the CA rat model induced by ovalbumin (OVA) along with cold stimulation. The effects of SMD and TAS2R10 expression in CA rats were evaluated using the following methods: clinical symptoms, weights, pathological staining, immunofluorescence staining (IF), enzyme-linked immunosorbent assay (ELISA), real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot (WB). Assays in vitro including cell counting Kit-8 (CCK-8), ELISA, flow cytometry, TUNEL staining, RT-qPCR and WB were performed to investigate potential mechanism of SMD on the proliferation and apoptosis of ASMCs through upregulation of TAS2R10. RESULTS: The administration of SMD resulted in a notable improvement in the symptoms, trends in weight, airway inflammation and airway remodeling observed in CA rats with upregulated TAS2R10. Mechanistically, we furtherly confirmed that SMD inhibits p70S6K/CyclinD1 pathway by upregulating TAS2R10. SMD furthermore blocked the G0/G1 phase, suppressed the proliferation and inducted apoptosis in ASMCs induced by platelet-derived growth factor-BB (PDGF-BB). Erythromycin (EM), a TAS2R10 agonist, can intensify these effects. CONCLUSIONS: SMD significantly ameliorates CA by upregulating TAS2R10 and inhibiting the p70S6K/CyclinD1 pathway, thereby modulating ASMCs' proliferation and apoptosis. Inspired by the Five Flavors Theory of Traditional Chinese Medicine, this study provides an updated treatment perspective for treating CA.

Jolkinolide B attenuates allergic airway inflammation and airway remodeling in asthmatic mice.

Asthma is a widely prevalent chronic disease that brings great suffering to patients and may result in death if it turns severe. Jolkinolide B (JB) is one diterpenoid component separated from the dried roots of Euphorbia fischeriana Steud (Euphorbiaceae), and has anti--inflammatory, antioxidative, and antitumor properties. However, the detailed regulatory role and associated regulatory mechanism in the progression of asthma remain elusive. In this work, it was demonstrated that the extensive infiltration of bronchial inflammatory cells and the thickening of airway wall were observed in ovalbumin (OVA)-induced mice, but these impacts were reversed by JB (10 mg/kg) treatment, indicating that JB relieved the provocative symptoms in OVA-induced asthma mice. In addition, JB can control OVA-triggered lung function and pulmonary resistance. Moreover, JB attenuated OVA-evoked inflammation by lowering the levels of interleukin (IL)-4, IL-5, and IL-13. Besides, the activated nuclear factor kappa B (NF-κB) and transforming growth factor-beta-mothers against decapentaplegic homolog 3 (TGFß/smad3) pathways in OVA-induced mice are rescued by JB treatment. In conclusion, it was disclosed that JB reduced allergic airway inflammation and airway remodeling in asthmatic mice by modulating the NF-κB and TGFß/smad3 pathways. This work could offer new opinions on JB for lessening progression of asthma.

FOXK2 facilitates the airway remodeling during chronic asthma by promoting glycolysis in a SIRT2-dependent manner.

Asthma is a chronic pulmonary disease with the worldwide prevalence. The structural alterations of airway walls, termed as "airway remodeling", are documented as the core contributor to the airway dysfunction during chronic asthma. Forkhead box transcription factor FOXK2 is a critical regulator of glycolysis, a metabolic reprogramming pathway linked to pulmonary fibrosis. However, the role of FOXK2 in asthma waits further explored. In this study, the chronic asthmatic mice were induced via ovalbumin (OVA) sensitization and repetitive OVA challenge. FOXK2 was upregulated in the lungs of OVA mice and downregulated after adenovirus-mediated FOXK2 silencing. The lung inflammation, peribronchial collagen deposition, and glycolysis in OVA mice were obviously attenuated after FOXK2 knockdown. Besides, the expressions of FOXK2 and SIRT2 in human bronchial epithelial cells (BEAS-2B) were increasingly upregulated upon TGF-ß1 stimulation and downregulated after FOXK2 knockdown. Moreover, the functional loss of FOXK2 remarkably suppressed TGF-ß1-induced epithelial-mesenchymal transition (EMT) and glycolysis in BEAS-2B cells, as manifested by the altered expressions of EMT markers and glycolysis enzymes. The glycolysis inhibitor 2-deoxy-d-glucose (2-DG) inhibited the EMT in TGF-ß1-induced cells, making glycolysis a driver of EMT. The binding of FOXK2 to SIRT2 was validated, and SIRT2 overexpression blocked the FOXK2 knockdown-mediated inhibition of EMT and glycolysis in TGF-ß1-treated cells, which suggests that FOXK2 regulates EMT and glycolysis in TGF-ß1-treated cells in a SIRT2-dependnet manner. Collectively, this study highlights the protective effect of FOXK2 knockdown on airway remodeling during chronic asthma.

T cell and airway smooth muscle interaction: a key driver of asthmatic airway inflammation and remodelling.

Crosstalk between T cells and airway smooth muscle (ASM) may play a role in modulating asthmatic airway inflammation and remodelling. Infiltrating T cells have been observed within the ASM bundles of asthmatics, and a wide range of direct and indirect interactions between T cells and ASM have been demonstrated using various in vitro and in vivo model systems. Contact-dependent mechanisms such as ligation and activation of cellular adhesion and costimulatory molecules, as well as the formation of lymphocyte-derived membrane conduits, facilitate the adhesion, bidirectional communication and transfer of materials between T and ASM cells. T cell-derived cytokines, particularly of the Th1, Th2 and Th17 subsets, modulate the secretome, proliferation and contractility of ASM cells. This review summarizes the mechanisms governing T cell-ASM crosstalk in the context of asthma. Understanding the underlying mechanistic basis is important for directing future research and developing therapeutic interventions targeted towards this complex interaction.

C-Phycocyanin Prevents Oxidative Stress, Inflammation, and Lung Remodeling in an Ovalbumin-Induced Rat Asthma Model.

Asthma is a chronic immunological disease related to oxidative stress and chronic inflammation; both processes promote airway remodeling with collagen deposition and matrix thickening, causing pulmonary damage and lost function. This study investigates the immunomodulation of C-phycocyanin (CPC), a natural blue pigment purified from cyanobacteria, as a potential alternative treatment to prevent the remodeling process against asthma. We conducted experiments using ovalbumin (OVA) to induce asthma in Sprague Dawley rats. Animals were divided into five groups: (1) sham + vehicle, (2) sham + CPC, (3) asthma + vehicle, (4) asthma + CPC, and (5) asthma + methylprednisolone (MP). Our findings reveal that asthma promotes hypoxemia, leukocytosis, and pulmonary myeloperoxidase (MPO) activity by increasing lipid peroxidation, reactive oxygen and nitrogen species, inflammation associated with Th2 response, and airway remodeling in the lungs. CPC and MP treatment partially prevented these physiological processes with similar action on the biomarkers evaluated. In conclusion, CPC treatment enhanced the antioxidant defense system, thereby preventing oxidative stress and reducing airway inflammation by regulating pro-inflammatory and anti-inflammatory cytokines, consequently avoiding asthma-induced airway remodeling.

Novel hypoxia-induced HIF-1αactivation in asthma pathogenesis.

BACKGROUND: Asthma's complexity, marked by airway inflammation and remodeling, is influenced by hypoxic conditions. This study focuses on the role of Hypoxia-Inducible Factor-1 Alpha (HIF-1α) and P53 ubiquitination in asthma exacerbation. METHODS: High-throughput sequencing and bioinformatics were used to identify genes associated with asthma progression, with an emphasis on GO and KEGG pathway analyses. An asthma mouse model was developed, and airway smooth muscle cells (ASMCs) were isolated to create an in vitro hypoxia model. Cell viability, proliferation, migration, and apoptosis were assessed, along with ELISA and Hematoxylin and Eosin (H&E) staining. RESULTS: A notable increase in HIF-1α was observed in both in vivo and in vitro asthma models. HIF-1α upregulation enhanced ASMCs' viability, proliferation, and migration, while reducing apoptosis, primarily via the promotion of P53 ubiquitination through MDM2. In vivo studies showed increased inflammatory cell infiltration and airway structural changes, which were mitigated by the inhibitor IDF-11,774. CONCLUSION: The study highlights the critical role of the HIF-1α-MDM2-P53 axis in asthma, suggesting its potential as a target for therapeutic interventions. The findings indicate that modulating this pathway could offer new avenues for treating the complex respiratory disorder of asthma.

[Effects of iris xanthin on airway inflammation, airway remodeling, and the HMGB1/TLR4/NF-κB pathway in asthmatic young mice]. / é¸¢å°¾é»„ç´ å¯¹å“®å–˜å¹¼é¼ æ°”é“ç‚Žç—‡ã€æ°”é“é‡å¡‘åŠHMGB1/TLR4/NF-κB通路的影响.

OBJECTIVES: To explore the effects of iris xanthin on airway inflammation, airway remodeling, and the high mobility group box 1 protein (HMGB1)/Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) pathway in asthmatic young mice. METHODS: Sixty male BALB/c young mice were randomly assigned into six groups: a blank group, a model group, a dexamethasone group, and low, medium, and high dose groups of iris xanthin, with ten mice per group. Asthma models were induced through intraperitoneal injections of a sensitizing agent [ovalbumin (OVA) 20 µg + aluminum hydroxide gel 2 mg], followed by 4% OVA aerosol inhalation. Lung function was measured using a pulmonary function tester to determine lung volume (LV), resting ventilation per minute (VE), and airway reactivity (Penh value). Hematoxylin-eosin (HE) staining was employed to examine and analyze airway remodeling. The contents of interleukin (IL)-1ß, IL-6, and tumor necrosis factor alpha (TNF-α) in bronchoalveolar lavage fluid were quantified using ELISA. Real-time fluorescence quantitative polymerase chain reaction and Western blot analysis were used to assess the expression of HMGB1/TLR4/NF-κB pathway-related mRNA and proteins in lung tissues. RESULTS: Compared to the model group, the dexamethasone and iris xanthin-treated groups (low, medium, and high doses) exhibited significant increases in LV and VE (P<0.05), with incremental dose-dependent increases observed in the iris xanthin groups. Additionally, Penh values, IL-1ß, IL-6, TNF-α, and airway remodeling indicators, along with mRNA levels of HMGB1, TLR4, and NF-κB p65 and protein levels of HMGB1, TLR4, and p-NF-κB p65, were all reduced (P<0.05) in a dose-dependent manner. When compared to the dexamethasone group, the low and medium dose iris xanthin groups showed decreases in LV and VE (P<0.05), whereas Penh values, IL-1ß, IL-6, TNF-α, and airway remodeling indicators, along with mRNA levels of HMGB1, TLR4, NF-κB p65 and protein levels of HMGB1, TLR4, and p-NF-κB p65, were increased (P<0.05). No significant differences were noted in these indices between the high dose iris xanthin group and the dexamethasone group (P>0.05). CONCLUSIONS: Iris xanthin can effectively alleviates airway inflammation and inhibits airway remodeling in asthmatic young mice, possibly through the suppression of the HMGB1/TLR4/NF-κB pathway.

Targeting lysyl oxidase like 2 attenuates OVA-induced airway remodeling partly via the AKT signaling pathway.

BACKGROUND: Airway epithelium is an important component of airway structure and the initiator of airway remodeling in asthma. The changes of extracellular matrix (ECM), such as collagen deposition and structural disturbance, are typical pathological features of airway remodeling. Thus, identifying key mediators that derived from airway epithelium and capable of modulating ECM may provide valuable insights for targeted therapy of asthma. METHODS: The datasets from Gene Expression Omnibus database were analyzed to screen differentially expressed genes in airway epithelium of asthma. We collected bronchoscopic biopsies and serum samples from asthmatic and healthy subjects to assess lysyl oxidase like 2 (LOXL2) expression. RNA sequencing and various experiments were performed to determine the influences of LOXL2 knockdown in ovalbumin (OVA)-induced mouse models. The roles and mechanisms of LOXL2 in bronchial epithelial cells were explored using LOXL2 small interfering RNA, overexpression plasmid and AKT inhibitor. RESULTS: Both bioinformatics analysis and further experiments revealed that LOXL2 is highly expressed in airway epithelium of asthmatics. In vivo, LOXL2 knockdown significantly inhibited OVA-induced ECM deposition and epithelial-mesenchymal transition (EMT) in mice. In vitro, the transfection experiments on 16HBE cells demonstrated that LOXL2 overexpression increases the expression of N-cadherin and fibronectin and reduces the expression of E-cadherin. Conversely, after silencing LOXL2, the expression of E-cadherin is up-regulated. In addition, the remodeling and EMT process that induced by transforming growth factor-ß1 could be enhanced and weakened after LOXL2 overexpression and silencing in 16HBE cells. Combining the RNA sequencing of mouse lung tissues and experiments in vitro, LOXL2 was involved in the regulation of AKT signaling pathway. Moreover, the treatment with AKT inhibitor in vitro partially alleviated the consequences associated with LOXL2 overexpression. CONCLUSIONS: Taken together, the results demonstrated that epithelial LOXL2 plays a role in asthmatic airway remodeling partly via the AKT signaling pathway and highlighted the potential of LOXL2 as a therapeutic target for airway remodeling in asthma.

Association of Small Airway Functional Indices With Respiratory Symptoms and Comorbidity in Asthmatics: A National Cross-Sectional Study.

Background: Small airway dysfunction (SAD) and airway inflammation are vital in asthma exacerbations. Type 2 inflammation (T2), mediated by cytokines from T helper 2 cell (Th2) such as interleukin (IL)-4, IL-5, and IL-13, is a potential mechanism underlying SAD. Research on small airway function in asthma is limited. We aimed to explore the correlation between small airway function and respiratory symptoms and comorbidity in T2 and non-T2 asthma. Methods: Derived from the National Health and Nutrition Examination Survey (NHANES), our study encompassed 2,420 asthma patients aged 6 - 79 years, including pulmonary function (PF) data such as forced expiratory flow between 25% and 75% of forced vital capacity (FEF25-75), forced expiratory volume in 1 second (FEV1), forced expiratory volume in 3 seconds (FEV3), forced expiratory volume in 6 seconds (FEV6), and forced vital capacity (FVC). To evaluate the small airway function, we calculated z-scores for FEF25-75, FEF25-75/FVC, FEV1/FEV6, and FEV3/FEV6. Logistic regression determined the adjusted odds ratios (aORs) for symptoms and comorbidity. Results: FEF25-75, FEV1/FEV6, and FEV3/FEV6 correlated with asthmatic symptoms. FEF25-75 had the strongest association with wheezing or whistling attacks. An increase of 1 standard deviations (SD) in FEF25-75 reduced recurrent wheezing (aOR: 0.70; 95% confidence intervals (95% CIs): 0.65 - 0.76) and severe attacks (aOR: 0.67; 95% CI: 0.62 - 0.94). These indices were also linked to dry cough and hay fever, particularly FEV3/FEV6 reducing hay fever risk (aOR: 0.70; 95% CI: 0.55 - 0.91) in non-T2 asthma. FEF25-75/FVC related to persistent (aOR: 0.78; 95% CI: 0.72 - 0.84) and severe attacks (aOR: 1.14; 95% CI: 1.08 - 1.22) in non-T2 groups. Lower indices combined with T2 exposure raised severe attack risk. Conclusions: In this nationwide study, small airway function correlated with symptom onset, especially in T2 asthma. Small airway injury differed between T2 and non-T2 asthma. Prospective research is needed to establish reference values.

Effects of MAL gene knockout on lung tissue morphology and on E-cad and α-SMA expression in asthma mouse models.

OBJECTIVES: To investigate the effects of myelin- and lymphocyte-associated protein (MAL) gene knockout on the morphological structure of lung tissue and the expression of E-cadherin (E-cad) and alpha-smooth muscle actin (α-SMA) in an asthmatic mouse model. METHODS: Twenty-four specific pathogen-free (SPF) C57BL/6J mice were divided into four groups: the wild-type normal (WT/SAL), wild-type asthmatic (WT/OVA), gene knockout normal (MAL-/-/SAL), and gene knockout asthmatic (MAL-/-/OVA) groups. The establishment of the asthma mouse models was confirmed by evaluating behavioral symptoms and histopathological H&E and Masson staining. Western blotting and RT-qPCR were used to measure E-cad and α-SMA expression levels in lung tissues. RESULTS: H&E staining of mouse lung tissues from WT/OVA, MAL-/-/SAL, and MAL-/-/OVA groups revealed a thickened bronchial wall, irregular lumen edge, locally fallen mucosal epithelium, and inflammatory cell infiltration compared with those of the WT/SAL group. In the WT and MAL-/- groups, the proportion of Masson-stained tissues in the OVA group was greater than that in the SAL group (p < 0.05). Compared with those in the WT/SAL group, the expression levels of α-SMA mRNA and protein were increased, while those of E-cad were decreased in the WT/OVA group (p < 0.01). Similarly, compared with those in the MAL-/-/SAL group, the expression levels of E-cad mRNA and protein were increased, while those of α-SMA were decreased in the MAL-/-/OVA group (p < 0.01). All these differences were statistically significant (p < 0.01). CONCLUSIONS: The MAL gene contributes to EMT inhibition and the stability of the airway barrier under normal physiological conditions by regulating E-cad and α-SMA expression.

Wnt5a-mediated autophagy contributes to the epithelial-mesenchymal transition of human bronchial epithelial cells during asthma.

BACKGROUND: The epithelial-mesenchymal transition (EMT) of human bronchial epithelial cells (HBECs) is essential for airway remodeling during asthma. Wnt5a has been implicated in various lung diseases, while its role in the EMT of HBECs during asthma is yet to be determined. This study sought to define whether Wnt5a initiated EMT, leading to airway remodeling through the induction of autophagy in HBECs. METHODS: Microarray analysis was used to investigate the expression change of WNT5A in asthma patients. In parallel, EMT models were induced using 16HBE cells by exposing them to house dust mites (HDM) or interleukin-4 (IL-4), and then the expression of Wnt5a was observed. Using in vitro gain- and loss-of-function approaches via Wnt5a mimic peptide FOXY5 and Wnt5a inhibitor BOX5, the alterations in the expression of the epithelial marker E-cadherin and the mesenchymal marker protein were observed. Mechanistically, the Ca2+/CaMKII signaling pathway and autophagy were evaluated. An autophagy inhibitor 3-MA was used to examine Wnt5a in the regulation of autophagy during EMT. Furthermore, we used a CaMKII inhibitor KN-93 to determine whether Wnt5a induced autophagy overactivation and EMT via the Ca2+/CaMKII signaling pathway. RESULTS: Asthma patients exhibited a significant increase in the gene expression of WNT5A compared to the healthy control. Upon HDM and IL-4 treatments, we observed that Wnt5a gene and protein expression levels were significantly increased in 16HBE cells. Interestingly, Wnt5a mimic peptide FOXY5 significantly inhibited E-cadherin and upregulated α-SMA, Collagen I, and autophagy marker proteins (Beclin1 and LC3-II). Rhodamine-phalloidin staining showed that FOXY5 resulted in a rearrangement of the cytoskeleton and an increase in the quantity of stress fibers in 16HBE cells. Importantly, blocking Wnt5a with BOX5 significantly inhibited autophagy and EMT induced by IL-4 in 16HBE cells. Mechanistically, autophagy inhibitor 3-MA and CaMKII inhibitor KN-93 reduced the EMT of 16HBE cells caused by FOXY5, as well as the increase in stress fibers, cell adhesion, and autophagy. CONCLUSION: This study illustrates a new link in the Wnt5a-Ca2+/CaMKII-autophagy axis to triggering airway remodeling. Our findings may provide novel strategies for the treatment of EMT-related diseases.