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.

Diacylglycerol kinase is a keystone regulator of signaling relevant to the pathophysiology of asthma.

Signal transduction by G protein-coupled receptors (GPCRs), receptor tyrosine kinases (RTKs) and immunoreceptors converge at the activation of phospholipase C (PLC) for the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). This is a point for second-messenger bifurcation where DAG via protein kinase C (PKC) and IP3 via calcium activate distinct protein targets and regulate cellular functions. IP3 signaling is regulated by multiple calcium influx and efflux proteins involved in calcium homeostasis. A family of lipid kinases belonging to DAG kinases (DGKs) converts DAG to phosphatidic acid (PA), negatively regulating DAG signaling and pathophysiological functions. PA, through a series of biochemical reactions, is recycled to produce new molecules of PIP2. Therefore, DGKs act as a central switch in terminating DAG signaling and resynthesis of membrane phospholipids precursor. Interestingly, calcium and PKC regulate the activation of α and ζ isoforms of DGK that are predominantly expressed in airway and immune cells. Thus, DGK forms a feedback and feedforward control point and plays a crucial role in fine-tuning phospholipid stoichiometry, signaling, and functions. In this review, we discuss the previously underappreciated complex and intriguing DAG/DGK-driven mechanisms in regulating cellular functions associated with asthma, such as contraction and proliferation of airway smooth muscle (ASM) cells and inflammatory activation of immune cells. We highlight the benefits of manipulating DGK activity in mitigating salient features of asthma pathophysiology and shed light on DGK as a molecule of interest for heterogeneous diseases such as asthma.

A novel DNase assay reveals low DNase activity in severe asthma.

Secreted deoxyribonucleases (DNases), such as DNase-I and DNase-IL3, degrade extracellular DNA, and endogenous DNases have roles in resolving airway inflammation and guarding against autoimmune responses to nucleotides. Subsets of patients with asthma have high airway DNA levels, but information about DNase activity in health and in asthma is lacking. To characterize DNase activity in health and in asthma, we developed a novel kinetic assay using a Taqman probe sequence that is quickly cleaved by DNase-I to produce a large product signal. We used this kinetic assay to measure DNase activity in sputum from participants in the Severe Asthma Research Program (SARP)-3 (n = 439) and from healthy controls (n = 89). We found that DNase activity was lower than normal in asthma [78.7 relative fluorescence units (RFU)/min vs. 120.4 RFU/min, P < 0.0001]. Compared to patients with asthma with sputum DNase activity in the upper tertile activity levels, those in the lower tertile of sputum DNase activity were characterized clinically by more severe disease and pathologically by airway eosinophilia and airway mucus plugging. Carbamylation of DNase-I, a post-translational modification that can be mediated by eosinophil peroxidase, inactivated DNase-I. In summary, a Taqman probe-based DNase activity assay uncovers low DNase activity in the asthma airway that is associated with more severe disease and airway mucus plugging and may be caused, at least in part, by eosinophil-mediated carbamylation.NEW & NOTEWORTHY We developed a new DNase assay and used it to show that DNase activity is impaired in asthma airways.

Automated high-throughput in vitro assays to identify metabolic hotspots and protease stability of structurally diverse, pharmacologically active peptides for inhalation.

The inhalation of peptides comes with the advantage of directly targeting the lung as tissue of interest. However, peptides are often rapidly metabolized in lung tissue through proteolytic cleavage. We have developed an assay workflow to obtain half-life and metabolite ID data for peptides incubated with four proteases abundant in lungs of asthma and COPD patients. The assay system has been validated using 28 structurally diverse linear and cyclic peptides with a molecular weight between 708 and 5808 Da. Experimental conditions for incubation, sample preparation, chromatography, data acquisition and analysis are compatible with the required throughput in early stage peptide projects. Together with co-crystal structures and Ala scans, we are using the described assay workflow to guide the first chemical modifications of peptide hits in early respiratory drug discovery projects.

15LO1 dictates glutathione redox changes in asthmatic airway epithelium to worsen type 2 inflammation.

Altered redox biology challenges all cells, with compensatory responses often determining a cell's fate. When 15 lipoxygenase 1 (15LO1), a lipid-peroxidizing enzyme abundant in asthmatic human airway epithelial cells (HAECs), binds phosphatidylethanolamine-binding protein 1 (PEBP1), hydroperoxy-phospholipids, which drive ferroptotic cell death, are generated. Peroxidases, including glutathione peroxidase 4 (GPX4), metabolize hydroperoxy-phospholipids to hydroxy derivatives to prevent ferroptotic death, but consume reduced glutathione (GSH). The cystine transporter SLC7A11 critically restores/maintains intracellular GSH. We hypothesized that high 15LO1, PEBP1, and GPX4 activity drives abnormal asthmatic redox biology, evidenced by lower bronchoalveolar lavage (BAL) fluid and intraepithelial cell GSH:oxidized GSH (GSSG) ratios, to enhance type 2 (T2) inflammatory responses. GSH, GSSG (enzymatic assays), 15LO1, GPX4, SLC7A11, and T2 biomarkers (Western blot and RNA-Seq) were measured in asthmatic and healthy control (HC) cells and fluids, with siRNA knockdown as appropriate. GSSG was higher and GSH:GSSG lower in asthmatic compared with HC BAL fluid, while intracellular GSH was lower in asthma. In vitro, a T2 cytokine (IL-13) induced 15LO1 generation of hydroperoxy-phospholipids, which lowered intracellular GSH and increased extracellular GSSG. Lowering GSH further by inhibiting SLC7A11 enhanced T2 inflammatory protein expression and ferroptosis. Ex vivo, redox imbalances corresponded to 15LO1 and SLC7A11 expression, T2 biomarkers, and worsened clinical outcomes. Thus, 15LO1 pathway-induced redox biology perturbations worsen T2 inflammation and asthma control, supporting 15LO1 as a therapeutic target.

Emodin inhibits NF-κB signaling pathway to protect obese asthmatic rats from pathological damage via Visfatin.

PURPOSE: Emodin has a protective effect on asthma. Obesity is closely related to asthma. We further explored the role of Emodin in obese asthmatic rats. METHODS: Ovalbumin (OVA) was used to induce asthma model, and high fat diet (HFD) was used to induce obese rat model. Body weight was measured before and after the modeling. Serum lipid levels were evaluated using commercial kits. Then, lung tissue and airway tissue of rat were separated forin vivo. Hematoxylin-eosin staining (HE) analyzed the extent of lung lesions. Quantitative reverse transcription PCR assessed the mRNA expression of Visfatin and Enzyme linked immunosorbent assay measured NF-κB protein expression in airway tissues. MTT, Brdu and Western blot detected cell viability, proliferation and NF-κB level of human bronchial epithelial cells 16HBE, respectively. RESULTS: Asthma and Emodin alone had no effect on the body weight of normal rats, while HFD promoted the body weight of rats and could be reversed by Emodin. Both asthma and obesity promoted the pathological damage of rat lungs, including emphysema, lipid accumulation, edema changes, lymphoid hypertrophy and airway smooth muscle hyperplasia as well as lipid accumulation in surum, and Emodin treatment could reduce the damage. In the airway tissues of asthma and obesity models, up-regulated Visfatin mRNA and NF-κB protein were observed. In 16HBE, Emodin reversed Visfatin's role in promoting cell viability, proliferation and activating NF-κB signaling pathway. CONCLUSION: Emodin inhibited NF-κB expression to relieve the pathological symptoms of obese asthmatic rats by Visfatin.

Aberrance of Zinc Metalloenzymes-Induced Human Diseases and Its Potential Mechanisms.

Zinc, an essential micronutrient in the human body, is a component in over 300 enzymes and participates in regulating enzymatic activity. Zinc metalloenzymes play a crucial role in physiological processes including antioxidant, anti-inflammatory, and immune responses, as well as apoptosis. Aberrant enzyme activity can lead to various human diseases. In this review, we summarize zinc homeostasis, the roles of zinc in zinc metalloenzymes, the physiological processes of zinc metalloenzymes, and aberrant zinc metalloenzymes in human diseases. In addition, potential mechanisms of action are also discussed. This comprehensive understanding of the mechanisms of action of the regulatory functions of zinc in enzyme activity could inform novel zinc-micronutrient-supply strategies for the treatment of diseases.

SB203580-A Potent p38 MAPK Inhibitor Reduces the Profibrotic Bronchial Fibroblasts Transition Associated with Asthma.

Subepithelial fibrosis is a component of the remodeling observed in the bronchial wall of patients diagnosed with asthma. In this process, human bronchial fibroblasts (HBFs) drive the fibroblast-to-myofibroblast transition (FMT) in response to transforming growth factor-ß1 (TGF-ß1), which activates the canonical Smad-dependent signaling. However, the pleiotropic properties of TGF-ß1 also promote the activation of non-canonical signaling pathways which can affect the FMT. In this study we investigated the effect of p38 mitogen-activated protein kinase (MAPK) inhibition by SB203580 on the FMT potential of HBFs derived from asthmatic patients using immunocytofluorescence, real-time PCR and Western blotting methods. Our results demonstrate for the first time the strong effect of p38 MAPK inhibition on the TGF-ß1-induced FMT potential throughout the strong attenuation of myofibroblast-related markers: α-smooth muscle actin (α-SMA), collagen I, fibronectin and connexin 43 in HBFs. We suggest the pleiotropic mechanism of SB203580 on FMT impairment in HBF populations by the diminishing of TGF-ß/Smad signaling activation and disturbances in the actin cytoskeleton architecture along with the maturation of focal adhesion sites. These observations justify future research on the role of p38 kinase in FMT efficiency and bronchial wall remodeling in asthma.

The Impact of Coronavirus Disease 2019 on Pediatric Asthma in the United States.

The coronavirus disease 2019 (COVID-19) pandemic has caused severe economic and health impacts in the United States, and the impact is disproportionately more in socially disadvantages areas. The available data, albeit limited in children, suggest that the initial concerns of the potential of serious impact of COVID-19 illness in children with asthma are unproven so far. The reduction in asthma morbidities is due to improved adherence, COVID-19 control measures, school closures, and decreased exposure to allergens and viral infections in children. During the pandemic, asthma guidelines were updated to guide physicians in asthma care. In the face of unprecedented time, it is important to be vigilant, adhere to treatment guidelines, and implement preventive measures to eradicate the virus and improve outcomes in children with asthma.

Angiotensin-Converting Enzyme 2 (ACE2) as a Potential Diagnostic and Prognostic Biomarker for Chronic Inflammatory Lung Diseases.

Chronic inflammatory lung diseases are characterized by uncontrolled immune response in the airways as their main pathophysiological manifestation. The lack of specific diagnostic and therapeutic biomarkers for many pulmonary diseases represents a major challenge for pulmonologists. The majority of the currently approved therapeutic approaches are focused on achieving disease remission, although there is no guarantee of complete recovery. It is known that angiotensin-converting enzyme 2 (ACE2), an important counter-regulatory component of the renin-angiotensin-aldosterone system (RAAS), is expressed in the airways. It has been shown that ACE2 plays a role in systemic regulation of the cardiovascular and renal systems, lungs and liver by acting on blood pressure, electrolyte balance control mechanisms and inflammation. Its protective role in the lungs has also been presented, but the exact pathophysiological mechanism of action is still elusive. The aim of this study is to review and discuss recent findings about ACE2, including its potential role in the pathophysiology of chronic inflammatory lung diseases:, i.e., chronic obstructive pulmonary disease, asthma, and pulmonary hypertension. Additionally, in the light of the coronavirus 2019 disease (COVID-19), we will discuss the role of ACE2 in the pathophysiology of this disease, mainly represented by different grades of pulmonary problems. We believe that these insights will open up new perspectives for the future use of ACE2 as a potential biomarker for early diagnosis and monitoring of chronic inflammatory lung diseases.

Role of miR-27a in the regulation of cellular function via the inhibition of MAP2K4 in patients with asthma.

Asthma is a respiratory disease with a clinically high incidence, and repeated attacks of asthma severely affect the quality of life and even pose a threat to health, leading to severe burdens on families and even the society. A thorough understanding of the pathogenesis of asthma is essential for the prevention and treatment of asthma. This study aimed to examine the effect of the microRNA miR-27a on asthma and its relationship with mitogen activated protein kinase 4 (MAP2K4). Patients with asthma admitted to our hospital from August 2016 to August 2018 and healthy participants in the same period were included in this prospective analysis. The mRNA expression levels of miR-27a and MAP2K4 in peripheral blood were determined. Airway smooth muscle cells (ASMCs) were used to study the effects of miR-27a and MAP2K4 on cell biological behavior. The relationship between miR-27a and MAP2K4 was verified using dual-luciferase reporter assay. miR-27a expression was increased and MAP2K4 mRNA expression was decreased in asthma (P < 0.05). Increasing miR-27a expression and inhibiting MAP2K4 expression could enhance the activity of ASMCs, whereas inhibiting miR-27a expression and increasing MAP2K4 expression had the opposite effect (P < 0.05). Dual-luciferase reporter assay results showed that the fluorescence activity of MAP2K4-wild type was inhibited by increased miR-27a expression (P < 0.05). miR-27a promotes the proliferation and invasion of ASMCs by targeting MAP2K4 and is involved in the occurrence of asthma.

Up-regulation of ACE2, the SARS-CoV-2 receptor, in asthmatics on maintenance inhaled corticosteroids.

BACKGROUND: The first step in SARS-CoV-2 infection is binding of the virus to angiotensin converting enzyme 2 (ACE2) on the airway epithelium. Asthma affects over 300 million people world-wide, many of whom may encounter SARS-CoV-2. Epidemiologic data suggests that asthmatics who get infected may be at increased risk of more severe disease. Our objective was to assess whether maintenance inhaled corticosteroids (ICS), a major treatment for asthma, is associated with airway ACE2 expression in asthmatics. METHODS: Large airway epithelium (LAE) of asthmatics treated with maintenance ICS (ICS+), asthmatics not treated with ICS (ICS-), and healthy controls (controls) was analyzed for expression of ACE2 and other coronavirus infection-related genes using microarrays. RESULTS: As a group, there was no difference in LAE ACE2 expression in all asthmatics vs controls. In contrast, subgroup analysis demonstrated that LAE ACE2 expression was higher in asthmatics ICS+ compared to ICS‾ and ACE2 expression was higher in male ICS+ compared to female ICS+ and ICS‾ of either sex. ACE2 expression did not correlate with serum IgE, absolute eosinophil level, or change in FEV1 in response to bronchodilators in either ICS- or ICS+. CONCLUSION: Airway ACE2 expression is increased in asthmatics on long-term treatment with ICS, an observation that should be taken into consideration when assessing the use of inhaled corticosteroids during the pandemic.

Critical Role of Lkb1 in the Maintenance of Alveolar Macrophage Self-Renewal and Immune Homeostasis.

Alveolar macrophages (AMs) are pivotal for maintaining lung immune homeostasis. We demonstrated that deletion of liver kinase b1 (Lkb1) in CD11c+ cells led to greatly reduced AM abundance in the lung due to the impaired self-renewal of AMs but not the impeded pre-AM differentiation. Mice with Lkb1-deficient AMs exhibited deteriorated diseases during airway Staphylococcus aureus (S. aureus) infection and allergic inflammation, with excessive accumulation of neutrophils and more severe lung pathology. Drug-mediated AM depletion experiments in wild type mice indicated a cause for AM reduction in aggravated diseases in Lkb1 conditional knockout mice. Transcriptomic sequencing also revealed that Lkb1 inhibited proinflammatory pathways, including IL-17 signaling and neutrophil migration, which might also contribute to the protective function of Lkb1 in AMs. We thus identified Lkb1 as a pivotal regulator that maintains the self-renewal and immune function of AMs.

Dysregulation of Pyruvate Kinase M2 Promotes Inflammation in a Mouse Model of Obese Allergic Asthma.

Obesity is a risk factor for the development of asthma and represents a difficult-to-treat disease phenotype. Aerobic glycolysis is emerging as a key feature of asthma, and changes in glucose metabolism are linked to leukocyte activation and adaptation to oxidative stress. Dysregulation of PKM2 (pyruvate kinase M2), the enzyme that catalyzes the last step of glycolysis, contributes to house dust mite (HDM)-induced airway inflammation and remodeling in lean mice. It remains unclear whether glycolytic reprogramming and dysregulation of PKM2 also contribute to obese asthma. The goal of the present study was to elucidate the functional role of PKM2 in a murine model of obese allergic asthma. We evaluated the small molecule activator of PKM2, TEPP46, and assessed the role of PKM2 using conditional ablation of the Pkm2 allele from airway epithelial cells. In obese C57BL/6NJ mice, parameters indicative of glycolytic reprogramming remained unchanged in the absence of stimulation with HDM. Obese mice that were subjected to HDM showed evidence of glycolytic reprogramming, and treatment with TEPP46 diminished airway inflammation, whereas parameters of airway remodeling were unaffected. Epithelial ablation of Pkm2 decreased central airway resistance in both lean and obese allergic mice in addition to decreasing inflammatory cytokines in the lung tissue. Lastly, we highlight a novel role for PKM2 in the regulation of glutathione-dependent protein oxidation in the lung tissue of obese allergic mice via a putative IFN-γ-glutaredoxin1 pathway. Overall, targeting metabolism and protein oxidation may be a novel treatment strategy for obese allergic asthma.

PTBP1 is necessary for dendritic cells to regulate T-cell homeostasis and antitumour immunity.

Dendritic cells (DCs) play an important role in linking innate and adaptive immunity. DCs can sense endogenous and exogenous antigens and present those antigens to T cells to induce an immune response or immune tolerance. During activation, alternative splicing (AS) in DCs is dramatically changed to induce cytokine secretion and upregulation of surface marker expression. PTBP1, an RNA-binding protein, is essential in alternative splicing, but the function of PTBP1 in DCs is unknown. Here, we found that a specific deficiency of Ptbp1 in DCs could increase MHC II expression and perturb T-cell homeostasis without affecting DC development. Functionally, Ptbp1 deletion in DCs could enhance antitumour immunity and asthma exacerbation. Mechanistically, we found that Pkm alternative splicing and a subset of Ifn response genes could be regulated by PTBP1. These findings revealed the function of PTBP1 in DCs and indicated that PTBP1 might be a novel therapeutic target for antitumour treatment.

Sputum ACE2, TMPRSS2 and FURIN gene expression in severe neutrophilic asthma.

BACKGROUND: Patients with severe asthma may have a greater risk of dying from COVID-19 disease. Angiotensin converting enzyme-2 (ACE2) and the enzyme proteases, transmembrane protease serine 2 (TMPRSS2) and FURIN, are needed for viral attachment and invasion into host cells. METHODS: We examined microarray mRNA expression of ACE2, TMPRSS2 and FURIN in sputum, bronchial brushing and bronchial biopsies of the European U-BIOPRED cohort. Clinical parameters and molecular phenotypes, including asthma severity, sputum inflammatory cells, lung functions, oral corticosteroid (OCS) use, and transcriptomic-associated clusters, were examined in relation to gene expression levels. RESULTS: ACE2 levels were significantly increased in sputum of severe asthma compared to mild-moderate asthma. In multivariate analyses, sputum ACE2 levels were positively associated with OCS use and male gender. Sputum FURIN levels were significantly related to neutrophils (%) and the presence of severe asthma. In bronchial brushing samples, TMPRSS2 levels were positively associated with male gender and body mass index, whereas FURIN levels with male gender and blood neutrophils. In bronchial biopsies, TMPRSS2 levels were positively related to blood neutrophils. The neutrophilic molecular phenotype characterised by high inflammasome activation expressed significantly higher FURIN levels in sputum than the eosinophilic Type 2-high or the pauci-granulocytic oxidative phosphorylation phenotypes. CONCLUSION: Levels of ACE2 and FURIN may differ by clinical or molecular phenotypes of asthma. Sputum FURIN expression levels were strongly associated with neutrophilic inflammation and with inflammasome activation. This might indicate the potential for a greater morbidity and mortality outcome from SARS-CoV-2 infection in neutrophilic severe asthma.

JNK modulates RAGE/ß-catenin signaling and is essential for allergic airway inflammation in asthma.

As a leading cause of occupational asthma, toluene diisocyanate (TDI)-induced asthma is an inflammatory disease of the airways with one of the most significant characteristics involving inflammation, in which the receptor of advanced glycation end products (RAGE) plays an extremely important role. However, the mechanism underlying the upregulation of RAGE is still unknown. The aim of the present study was to examine whether JNK mediates ß-catenin stabilization via activation of RAGE in asthma. Herein from the results by analyzing the blood from healthy donors and patients with asthma, it was found that the expression of RAGE and p-JNK is highly correlated and elevated concomitantly with the severity of bronchial asthma. Additionally, upon sensitizing and challenging the mice with TDI, we found that RAGE inhibitor (FPS-ZM1) and JNK inhibitor (SP600125) significantly reduced the TDI-induced asthma inflammation in vivo. Furthermore, SP600125 also considerably restored RAGE and p-JNK expression. Besides, the in vitro results from TDI-HSA treatment of 16HBE cells reveal that therapeutic inhibition of JNK reduced TDI driving RAGE expression and ß-catenin translocation, while treatment with Anisomycin, a JNK agonist, showed the opposite effect. Moreover, genetic knockdown of RAGE does not contribute to JNK phosphorylation, indicating that JNK functions upstream of RAGE. Collectively, these findings highlight a role for JNK signaling in RAGE/ß-catenin regulation and have important therapeutic implications for the treatment of TDI induced asthma.

Revisiting matrix metalloproteinase 12: its role in pathophysiology of asthma and related pulmonary diseases.

PURPOSE OF REVIEW: Matrix metalloproteinases (MMPs) are a family of over 20 zinc-dependent proteases with different biological and pathological activities, and many have been implicated in several diseases. Although nonselective MMP inhibitors are known to induce serious side-effects, targeting individual MMPs may offer a safer therapeutic potential for several diseases. Hence, we provide a concise overview on MMP-12, given its association with pulmonary diseases, including asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis, and other progressive pulmonary fibrosis (PPF), which may also occur in coronavirus disease 2019. RECENT FINDINGS: In asthma, COPD, and PPF, increased MMP-12 levels have been associated with inflammation and/or structural changes within the lungs and negatively correlated with functional parameters. Increased pulmonary MMP-12 levels and MMP-12 gene expression have been related to disease severity in asthma and COPD. Targeting MMP-12 showed potential in animal models of pulmonary diseases but human data are still very scarce. SUMMARY: Although there may be a potential role of MMP-12 in asthma, COPD and PPF, several pathophysiological aspects await elucidation. Targeting MMP-12 may provide further insights into MMP-12 related mechanisms and how this translates into clinical outcomes; this warrants further research.

Callicarpa japonica Thunb. ameliorates allergic airway inflammation by suppressing NF-κB activation and upregulating HO-1 expression.

ETHNOPHARMACOLOGICAL RELEVANCE: Callicarpa japonica Thunb., as an herbal medicine has been used for the treatment of inflammatory diseases in China and Korea. MATERIALS AND METHODS: Ultra performance liquid chromatography-photodiode array-quadrupole time-of-flight mass spectrometer (UPLC-PDA-QTof MS) was used to detect the major phenylethanoid glycosides in the C. japonica extract. BALB/c mice were intraperitoneally sensitized by ovalbumin (OVA) (on days 0 and 7) and challenged by OVA aerosol (on days 11-13) to induce airway inflammatory response. The mice were also administered with C. japonica Thunb. (CJT) (20 and 40 mg/kg Per oral) on days 9-13. CJT pretreatment was conducted in lipopolysaccharide (LPS)-stimulated RAW264.7 or phorbol 12-myristate 13-acetate (PMA)-stimulated A549 cells. RESULTS: CJT administration significantly reduced the secretion of Th2 cytokines, TNF-α, IL-6, immunoglobulin E (IgE) and histamine, and the recruitment of eosinophils in an OVA-exposed mice. In histological analyses, the amelioration of inflammatory cell influx and mucus secretion were observed with CJT. The OVA-induced airway hyperresponsiveness (AHR), iNOS expression and NF-κB activation were effectively suppressed by CJT administration. In addition, CJT led to the upregulation of HO-1 expression. In an in vitro study, CJT pretreatment suppressed the LPS-induced TNF-α secretion in RAW264.7 cells and attenuated the PMA-induced IL-6, IL-8 and MCP-1 secretion in A549 cells. These effects were accompanied by downregulated NF-κB phosphorylation and by upregulated HO-1 expression. CONCLUSION: These results suggested that CJT has protective activity against OVA-induced airway inflammation via downregulation of NF-κB activation and upregulation of HO-1, suggesting that CJT has preventive potential for the development of allergic asthma.

PTEN participates in airway remodeling of asthma by regulating CD38/Ca2+/CREB signaling.

Both phosphatase and tensin homologue deleted on chromosome ten (PTEN) and cluster of differentiation 38 (CD38) have been suggested to be key regulators of the pathogenesis of asthma. However, the precise role and molecular mechanisms by which PTEN and CD38 are involved in airway remodeling throughout asthma pathogenesis remains poorly understood. This study aimed to elucidate the role of PTEN and CD38 in airway remodeling of asthma. Exposure to tumor necrosis factor-α (TNF-α) in airway smooth muscle (ASM) cells markedly decreased PTEN expression, and increased expression of CD38. Overexpression of PTEN suppressed the expression of CD38 and downregulated proliferation and migration induced by TNF-α stimulation, which was partially reversed by CD38 overexpression. PTEN/CD38 axis regulated Ca2+ levels and cyclic AMP response-element binding protein (CREB) phosphorylation in TNF-α-stimulated ASM cells. The in vitro knockdown of CD38 or overexpression of PTEN remarkably restricted airway remodeling and decreased Ca2+ concentrations and CREB phosphorylation in asthmatic mice. CD38 overexpression abolished the inhibitory effects of PTEN overexpression on airway remodeling. These findings demonstrate that PTEN inhibits airway remodeling of asthma through the downregulation of CD38-mediated Ca2+/CREB signaling, highlighting a key role of PTEN/CD38/Ca2+/CREB signaling in the molecular pathogenesis of asthma.