Exendin-4 restores airway mucus homeostasis through the GLP1R-PKA-PPARγ-FOXA2-phosphatase signaling

Ubiquitin-specific protease-7 promotes expression of airway mucin MUC5AC via the NF-κB signaling pathway

Chronic obstructive pulmonary disease (COPD) and other respiratory diseases frequently present with airway mucus hypersecretion, which not only affects the patient's quality of life but also poses a constant threat to their life expectancy. Ubiquitin-specific protease 7 (USP7), a deubiquitinating enzyme, affects cell differentiation, tissue growth, and disease development. However, its role in airway mucus hypersecretion induced by COPD remains elusive. In this study, USP7 expression was significantly upregulated in airway epithelial samples from patients with COPD, and USP7 was also overexpressed in mouse lung and human airway epithelial cells in models of airway mucus hypersecretion. Inhibition of USP7 reduced the expression of nuclear factor kappa B (NF-κB), phosphorylated-NF-κB (p-NF-κB), and phosphonated inhibitor of nuclear factor kappa B (p-IκBα), and alleviated the airway mucus hypersecretion in vivo and in vitro. Further research revealed that USP7 stimulated airway mucus hypersecretion through the activation of NF-κB nuclear translocation. In addition, the expression of mucin 5AC (MUC5AC) was suppressed by the NF-κB inhibitor erdosteine. These findings suggest that USP7 stimulates the NF-κB signaling pathway, which promotes airway mucus hypersecretion. This study identifies one of the mechanisms regulating airway mucus secretion and provides a new potential target for its prevention and treatment.

LIRAGLUTIDE ALLEVIATES ACUTE LUNG INJURY AND MORTALITY IN PNEUMONIA-INDUCED SEPSIS THROUGH REGULATING SURFACTANT PROTEIN EXPRESSION AND SECRETION

ABSTRACT

Glucagon-like peptide 1 (GLP-1) analogs are used to treat type 2 diabetes, and they can regulate insulin secretion, energy homeostasis, inflammation, and immune cell function. This study sought to determine whether the GLP-1 analog liraglutide exerts a beneficial action in an acute lung injury model of pneumonia-induced sepsis. Methods: Wild-type FVB/NJ mice (n = 114) were infected by intratracheal injection with Pseudomonas aeruginosa Xen5 (4 × 10 4 CFU/mouse) or an equal volume (50 μL) of saline (control) with or without a subcutaneous injection of liraglutide (2 mg/kg, 30 min after infection). Mice were killed 24 h after infection. Lung tissues and BALF were analyzed. In separate experiments, the dynamic growth of bacteria and animal mortality was monitored using in vivo imaging system within 48 h after infection. In addition, primary lung alveolar type II cells isolated from mice were used to study the mechanism of liraglutide action. Result: Liraglutide improved survival ( P < 0.05), decreased bacterial loads in vivo , and reduced lung injury scores ( P < 0.01) in septic mice. Liraglutide-treated mice showed decreased levels of inflammatory cells ( P < 0.01) and proinflammatory cytokines (TNF-α and IL-6) ( P < 0.01) in the lung compared with septic controls. Liraglutide significantly increased pulmonary surfactant proteins (SP-A and SP-B) expression/secretion ( P < 0.01) and phospholipid secretion ( P < 0.01) in vivo . Primary alveolar type II cells pretreated with liraglutide improved SP-A and SP-B expression after LPS exposure ( P < 0.01). Conclusion: Liraglutide attenuates mortality and lung inflammation/injury in pneumonia-induced sepsis. The increased surfactant expression/secretion and anti-inflammatory effects of liraglutide represent potential mechanisms by GLP-1 agonists potentiate host defense and maintain alveolar respiratory function in acute lung injury.

The SIRT3 activator ganoderic acid D regulates airway mucin MUC5AC expression via the NRF2/GPX4 pathway

PURPOSE

The expression of MUC5AC, a highly prevalent airway mucin, is regulated by stimulatory factors such as oxidative stress. Ganoderic acid D (GAD) activates mitochondrial deacetylase SIRT3. SIRT3 regulates mitochondrial function through deacetylation of mitochondrial proteins, thereby playing a significant role in alleviating oxidative stress-related diseases. Therefore, this study aimed to investigate the mechanisms and rationale underlying the regulation of MUC5AC expression by GAD.

METHODS

Human airway epithelial cells (NCI-H292) were exposed to pyocyanin (PCN) to establish an in vitro cell model of airway mucus hypersecretion. The expression of SIRT3, MUC5AC, and NRF2 pathway proteins in cells was assessed. Cellular mitochondrial morphology and oxidative stress markers were analyzed. C57BL/6 mice were induced with Pseudomonas aeruginosa (PA) to establish an in vivo mouse model of airway mucus hypersecretion. The expression of SIRT3 and MUC5AC in the airways was examined. In addition, the differential expression of target genes in the airway epithelial tissues of patients with chronic obstructive pulmonary disease (COPD) was analyzed using publicly available databases.

RESULTS

The results revealed a significant upregulation of MUC5AC expression and a significant downregulation of SIRT3 expression in relation to airway mucus hypersecretion. GAD inhibited the overexpression of MUC5AC in PCN-induced NCI-H292 cells and PA-induced mouse airways by upregulating SIRT3. GAD activated the NRF2/GPX4 pathway and inhibited PCN-induced oxidative stress and mitochondrial morphological changes in NCI-H292 cells. However, ML385 inhibited the regulatory effects of GAD on MUC5AC expression.

CONCLUSION

The SIRT3 activator GAD downregulated MUC5AC expression, potentially through activation of the NRF2/GPX4 pathway. Accordingly, GAD may be a potential treatment approach for airway mucus hypersecretions.

Glucagon-like peptide-1: a multi-faceted anti-inflammatory agent

Inflammation contributes to many chronic conditions. It is often associated with circulating pro-inflammatory cytokines and immune cells. GLP-1 levels correlate with disease severity. They are often elevated and can serve as markers of inflammation. Previous studies have shown that oxytocin, hCG, ghrelin, alpha-MSH and ACTH have receptor-mediated anti-inflammatory properties that can rescue cells from damage and death. These peptides have been studied well in the past century. In contrast, GLP-1 and its anti-inflammatory properties have been recognized only recently. GLP-1 has been proven to be a useful adjuvant therapy in type-2 diabetes mellitus, metabolic syndrome, and hyperglycemia. It also lowers HbA1C and protects cells of the cardiovascular and nervous systems by reducing inflammation and apoptosis. In this review we have explored the link between GLP-1, inflammation, and sepsis.

Lung proteome and metabolome endotype in HIV-associated obstructive lung disease

Purpose

Obstructive lung disease is increasingly common among persons with HIV, both smokers and nonsmokers. We used aptamer proteomics to identify proteins and associated pathways in HIV-associated obstructive lung disease.

Methods

Bronchoalveolar lavage fluid (BALF) samples from 26 persons living with HIV with obstructive lung disease were matched to persons living with HIV without obstructive lung disease based on age, smoking status and antiretroviral treatment. 6414 proteins were measured using SomaScan® aptamer-based assay. We used sparse distance-weighted discrimination (sDWD) to test for a difference in protein expression and permutation tests to identify univariate associations between proteins and forced expiratory volume in 1 s % predicted (FEV₁ % pred). Significant proteins were entered into a pathway over-representation analysis. We also constructed protein-driven endotypes using K-means clustering and performed over-representation analysis on the proteins that were significantly different between clusters. We compared protein-associated clusters to those obtained from BALF and plasma metabolomics data on the same patient cohort.

Results

After filtering, we retained 3872 proteins for further analysis. Based on sDWD, protein expression was able to separate cases and controls. We found 575 proteins that were significantly correlated with FEV₁ % pred after multiple comparisons adjustment. We identified two protein-driven endotypes, one of which was associated with poor lung function, and found that insulin and apoptosis pathways were differentially represented. We found similar clusters driven by metabolomics in BALF but not plasma.

Conclusion

Protein expression differs in persons living with HIV with and without obstructive lung disease. We were not able to identify specific pathways differentially expressed among patients based on FEV₁ % pred; however, we identified a unique protein endotype associated with insulin and apoptotic pathways.

Forkhead box protein A2 alleviates toll-like receptor 4-mediated inflammation, endoplasmic reticulum stress, autophagy, and apoptosis induced by lipopolysaccharide in bovine hepatocytes

Lipopolysaccharide (LPS) is an important stimulus of inflammation via binding to toll-like receptor 4 (TLR4), but the role of TLR4 in LPS-induced cellular homeostasis disruption indicated by the increased level of endoplasmic reticulum (ER) stress, autophagy, and apoptosis is unknown in the liver of dairy cows. Previous studies show that forkhead box protein A2 (FOXA2) is an important transcriptional factor to maintain cellular metabolic homeostasis, but the mechanisms by which FOXA2 mediates cellular homeostasis disruption in response to LPS remains unclear. To achieve the aims, hepatocytes separated from dairy cows at ∼160 d in milk were pretreated with a specific TLR4 inhibitor TAK-242 for 12 h, followed by LPS treatment for another 12 h to investigate the role of TLR4 in LPS-induced disruption of cellular homeostasis. The results indicated that LPS-induced nuclear factor-κB (NF-κB)-mediated inflammatory cascades, ER stress, autophagy, and apoptosis via activating TLR4 and downregulating FOXA2 expression in bovine hepatocytes. The application of TLR4 inhibitor alleviated LPS-induced inflammation through inactivating NF-κB proinflammatory pathway, restored cell homeostasis by decreasing the level of ER stress, autophagy, and apoptosis, and upregulated FOXA2 expression. Furthermore, we also elevated FOXA2 expression with an overexpression plasmid to clarify its molecular role in response to LPS challenge. FOXA2 overexpression reduced LPS-caused inflammation by inhibiting NF-κB signaling pathway. Also, FOXA2 could alleviate ER stress to block unfolded protein response and suppress autophagic flux. In addition, FOXA2 enhanced mitochondrial membrane potential via reducing pro-apoptotic protein BAX, CASPASE3, and Cleaved CASPASE3 expression and elevating anti-apoptotic protein BCL-2 expression to mitigate LPS-induced apoptosis. Taken together, these findings suggested that FOXA2 is a mediator to alleviate TLR4-controlled inflammation, ER stress, autophagy, and apoptosis in LPS-treated bovine hepatocytes, it could serve as a potential target to intervene cell homeostasis disruption caused by LPS in the liver of dairy cows.

The Role of Glucagon-Like Peptide-1 Receptor Agonists in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is one of the common diseases of the respiratory system. As the disease recurs, damage to the airways and lung tissue gradually worsens, leading to a progressive decline in lung function, affecting the patient's workforce and quality of life, and causing a huge social and economic burden. Diabetes is a common comorbidity of COPD and patients with COPD are at increased risk of developing diabetes, while hyperglycemia can also reduce lung function and contribute to the progression and poor prognosis of COPD. Glucagon-like peptide-1 receptor agonist (GLP-1RA) is a new type of hypoglycemic agent that has been shown to regulate blood glucose levels, reduce inflammatory responses and oxidative stress, and regulate lipid metabolism, among other effects. GLP-1RAs may benefit COPD patients by acting directly on the lung from mechanisms such as reducing the inflammatory response, improving oxidative stress, regulating protease/anti-protease imbalance, improving airway mucus homeostasis, and reducing airway remodeling. This study provides a review of the potential role of GLP-1RAs in COPD and offers new ideas for the prevention and treatment of COPD.

Tackling recalcitrant Pseudomonas aeruginosa infections in critical illness via anti-virulence monotherapy

Intestinal barrier derangement allows intestinal bacteria and their products to translocate to the systemic circulation. Pseudomonas aeruginosa (PA) superimposed infection in critically ill patients increases gut permeability and leads to gut-driven sepsis. PA infections are challenging due to multi-drug resistance (MDR), biofilms, and/or antibiotic tolerance. Inhibition of the quorum-sensing transcriptional regulator MvfR(PqsR) is a desirable anti-PA anti-virulence strategy as MvfR controls multiple acute and chronic virulence functions. Here we show that MvfR promotes intestinal permeability and report potent anti-MvfR compounds, the N-Aryl Malonamides (NAMs), resulting from extensive structure-activity-relationship studies and thorough assessment of the inhibition of MvfR-controlled virulence functions. This class of anti-virulence non-native ligand-based agents has a half-maximal inhibitory concentration in the nanomolar range and strong target engagement. Using a NAM lead in monotherapy protects murine intestinal barrier function, abolishes MvfR-regulated small molecules, ameliorates bacterial dissemination, and lowers inflammatory cytokines. This study demonstrates the importance of MvfR in PA-driven intestinal permeability. It underscores the utility of anti-MvfR agents in maintaining gut mucosal integrity, which should be part of any successful strategy to prevent/treat PA infections and associated gut-derived sepsis in critical illness settings. NAMs provide for the development of crucial preventive/therapeutic monotherapy options against untreatable MDR PA infections.

Pseudomonas aeruginosa infections are increasingly difficult to treat due to the development of antimicrobial resistance. Here, the authors describe the synthesis, characterisation and efficacy of a quorum sensing inhibitor.

PTEN: An Emerging Potential Target for Therapeutic Intervention in Respiratory Diseases

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a potent tumor suppressor that regulates several key cellular processes, including proliferation, survival, genomic integrity, migration, and invasion, via PI3K-dependent and independent mechanisms. A subtle decrease in PTEN levels or catalytic activity is implicated not only in cancer but also in a wide spectrum of other diseases, including various respiratory diseases. A systemic overview of the advances in the molecular and cellular mechanisms of PTEN involved in the initiation and progression of respiratory diseases may offer novel targets for the development of effective therapeutics for the treatment of respiratory diseases. In the present review, we highlight the novel findings emerging from current research on the role of PTEN expression and regulation in airway pathological conditions such as asthma/allergic airway inflammation, pulmonary hypertension (PAH), chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and other acute lung injuries (ALI). Moreover, we discuss the clinical implications of PTEN alteration and recently suggested therapeutic possibilities for restoration of PTEN expression and function in respiratory diseases.

The anti-inflammatory feature of glucagon-like peptide-1 and its based diabetes drugs—Therapeutic potential exploration in lung injury

Since 2005, GLP-1 receptor (GLP-1R) agonists (GLP-1RAs) have been developed as therapeutic agents for type 2 diabetes (T2D). GLP-1R is not only expressed in pancreatic islets but also other organs, especially the lung. However, controversy on extra-pancreatic GLP-1R expression still needs to be further resolved, utilizing different tools including the use of more reliable GLP-1R antibodies in immune-staining and co-immune-staining. Extra-pancreatic expression of GLP-1R has triggered extensive investigations on extra-pancreatic functions of GLP-1RAs, aiming to repurpose them into therapeutic agents for other disorders. Extensive studies have demonstrated promising anti-inflammatory features of GLP-1RAs. Whether those features are directly mediated by GLP-1R expressed in immune cells also remains controversial. Following a brief review on GLP-1 as an incretin hormone and the development of GLP-1RAs as therapeutic agents for T2D, we have summarized our current understanding of the anti-inflammatory features of GLP-1RAs and commented on the controversy on extra-pancreatic GLP-1R expression. The main part of this review is a literature discussion on GLP-1RA utilization in animal models with chronic airway diseases and acute lung injuries, including studies on the combined use of mesenchymal stem cell (MSC) based therapy. This is followed by a brief summary.

In vitro cell cultures of Brunner's glands from male mouse to study GLP-1 receptor function

Exocrine glands in the submucosa of the proximal duodenum secrete alkaline fluid containing mucus to protect the intestinal mucosa from acidic stomach contents. These glands, known as Brunner's gland, express high glucagon-like peptide 1 receptor (GLP-1R) levels. Previous studies have suggested that activation of the GLP-1R induces expression of barrier protective genes in Brunner's glands. Still, the lack of a viable in vitro culture of Brunner's glands has hampered additional studies of the functional consequences of GLP-1R activation. In this study, we established a procedure to isolate and culture cells derived from murine Brunner's glands. The isolated glandular cells retained functional GLP-1R expression in culture, making this in vitro system suitable for the study of GLP-1R activation. We found that cells derived from the Brunner's glands of mice pre-treated with semaglutide contained significantly more mucus compared to Brunner's glands from vehicle-treated mice. Our data suggest a protective intestinal response upon semaglutide treatment, but further studies are required to leverage the full potential of cultured Brunner's gland cells.

Deletion of natriuretic peptide receptor C alleviates adipose tissue inflammation in hypercholesterolemic Apolipoprotein E knockout mice

The inflammation of adipose tissue is one of the most common secondary pathological changes in atherosclerosis, which in turn influences the process of atherosclerosis. Natriuretic peptides have been revealed important effect in regulating adipose metabolism. However, the relationship between natriuretic peptide receptor C and inflammation of adipose tissue in atherosclerosis remains unknown. This study aims to explore the effect natriuretic peptide receptor C exerts on the regulation of the adipose inflammation in atherosclerotic mice induced by western-type diet and its overlying mechanisms. To clarify the importance of NPRC of adipose inflammation in atherosclerotic mice, NPRC expression was measured in mice fed with chow diet and western-type diet for 12 weeks and we found a considerable increase in adipose tissue of atherosclerotic mice. Global NPRC knockout in mice was bred onto ApoE^-/- mice to generate NPRC^-/- ApoE^-/- mice, which displayed remarked increase in browning of white adipose tissue and lipolysis of adipose tissue and decrease in adipose inflammation manifested by decreased macrophage invasion to form less CLS (crown-like structure), reduced oxidative stress and alleviated expression of TNFα, IL-6, IL-1β and MCP1, but increased expression of adiponectin in adipose tissue. Moreover, our study showed that white adipose tissue browning in NPRC^-/- ApoE^-/- atherosclerotic mice was associated with decreased inflammatory response through cAMP/PKA signalling activation. These results identify NPRC as a novel regulator for adipose inflammation in atherosclerotic mice by modulating white adipose tissue browning.

An Organ System-Based Synopsis of Pseudomonas aeruginosa Virulence

Driven in part by its metabolic versatility, high intrinsic antibiotic resistance, and a large repertoire of virulence factors, Pseudomonas aeruginosa is expertly adapted to thrive in a wide variety of environments, and in the process, making it a notorious opportunistic pathogen. Apart from the extensively studied chronic infection in the lungs of people with cystic fibrosis (CF), P. aeruginosa also causes multiple serious infections encompassing essentially all organs of the human body, among others, lung infection in patients with chronic obstructive pulmonary disease, primary ciliary dyskinesia and ventilator-associated pneumonia; bacteremia and sepsis; soft tissue infection in burns, open wounds and postsurgery patients; urinary tract infection; diabetic foot ulcers; chronic suppurative otitis media and otitis externa; and keratitis associated with extended contact lens use. Although well characterized in the context of CF, pathogenic processes mediated by various P. aeruginosa virulence factors in other organ systems remain poorly understood. In this review, we use an organ system-based approach to provide a synopsis of disease mechanisms exerted by P. aeruginosa virulence determinants that contribute to its success as a versatile pathogen.

Inhibitor Mimetic Mutations in the Pseudomonas aeruginosa PqsE Enzyme Reveal a Protein-Protein Interaction with the Quorum-Sensing Receptor RhlR That Is Vital for Virulence Factor Production

Pseudomonas aeruginosa is an opportunistic human pathogen that causes fatal infections. There exists an urgent need for new antimicrobial agents to combat P. aeruginosa. We conducted a screen for molecules that bind the virulence-controlling protein PqsE and characterized hit compounds for inhibition of PqsE enzymatic activity. The binding conformations of two inhibitory molecules, BB391 and BB393, were identified by crystallography, and inhibitor binding was mimicked by the substitution of PqsE residues E182 and S285 with tryptophan. Comparison of the inhibitor-mimetic mutations to the catalytically inactive PqsE D73A protein demonstrated that catalysis is not responsible for the role PqsE plays in driving virulence factor production. Rather, the PqsE E182W protein fails to interact with the quorum-sensing receptor, RhlR, and our results suggest that it is this interaction that is responsible for promoting virulence factor production in P. aeruginosa. These findings provide a new route for drug discovery efforts targeting PqsE.

Natural history and mechanisms of COPD

The natural history of COPD is complex, and the disease is best understood as a syndrome resulting from numerous interacting factors throughout the life cycle with smoking being the strongest inciting feature. Unfortunately, diagnosis is often delayed with several longitudinal cohort studies shedding light on the long 'preclinical' period of COPD. It is now accepted that individuals presenting with different COPD phenotypes may experience varying natural history of their disease. This includes its inception, early stages and progression to established disease. Several scenarios regarding lung function course are possible, but it may conceptually be helpful to distinguish between individuals with normal maximally attained lung function in their early adulthood who thereafter experience faster than normal FEV₁ decline, and those who may achieve a lower than normal maximally attained lung function. This may be the main mechanism behind COPD in the latter group, as the decline in FEV₁ during their adult life may be normal or only slightly faster than normal. Regardless of the FEV₁ trajectory, continuous smoking is strongly associated with disease progression, development of structural lung disease and poor prognosis. In developing countries, factors such as exposure to biomass and sequelae after tuberculosis may lead to a more airway-centred COPD phenotype than seen in smokers. Mechanistically, COPD is characterized by a combination of structural and inflammatory changes. It is unlikely that all patients share the same individual or combined mechanisms given the heterogeneity of resultant phenotypes. Lung explants, bronchial biopsies and other tissue studies have revealed important features. At the small airway level, progression of COPD is clinically imperceptible, and the pathological course of the disease is poorly described. Asthmatic features can further add confusion. However, the small airway epithelium is likely to represent a key focus of the disease, combining impaired subepithelial crosstalk and structural/inflammatory changes. Insufficient resolution of inflammatory processes may facilitate these changes. Pathologically, epithelial metaplasia, inversion of the goblet to ciliated cell ratio, enlargement of the submucosal glands and neutrophil and CD8-T-cell infiltration can be detected. Evidence of type 2 inflammation is gaining interest in the light of new therapeutic agents. Alarmin biology is a promising area that may permit control of inflammation and partial reversal of structural changes in COPD. Here, we review the latest work describing the development and progression of COPD with a focus on lung function trajectories, exacerbations and survival. We also review mechanisms focusing on epithelial changes associated with COPD and lack of resolution characterizing the underlying inflammatory processes.

Pulmonary Mycosis Drives Forkhead Box Protein A2 Degradation and Mucus Hypersecretion through Activation of the Spleen Tyrosine Kinase-Epidermal Growth Factor Receptor-AKT/Extracellular Signal-Regulated Kinase 1/2 Signaling

Pulmonary mycoses are difficult to treat and detrimental to patients. Fungal infections modulate the lung immune response, induce goblet cell hyperplasia and metaplasia, and mucus hypersecretion in the airways. Excessive mucus clogs small airways and reduces pulmonary function by decreasing oxygen exchange, leading to respiratory distress. The forkhead box protein A2 (FOXA2) is a transcription factor that regulates mucus homeostasis in the airways. However, little is known whether pulmonary mycosis modulates FOXA2 function. Herein, we investigated whether Blastomyces dermatitidis and Histoplasma capsulatum-infected canine and feline lungs and airway epithelial cells could serve as higher animal models to examine the relationships between fungal pneumonia and FOXA2-regulated airway mucus homeostasis. The results indicate that fungal infection down-regulated FOXA2 expression in airway epithelial cells, with concomitant overexpression of mucin 5AC (MUC5AC) and mucin 5B (MUC5B) mucins. Mechanistic studies reveal that B. dermatitidis infection, as well as β-glucan exposure, activated the Dectin-1-SYK-epidermal growth factor receptor-AKT/extracellular signal-regulated kinase 1/2 signaling pathway that inhibits the expression of FOXA2, resulting in overexpression of MUC5AC and MUC5B in canine airway cells. Further understanding of the role of FOXA2 in mucus hypersecretion may lead to novel therapeutics against excessive mucus in both human and veterinary patients with pulmonary mycosis.

PKA-Dependent Membrane Surface Recruitment of CI-AMPARs Is Crucial for BCP-Mediated Protection Against Post-acute Ischemic Stroke Cognitive Impairment

Post-acute ischemic stroke cognitive impairment frequently occurs and seriously affects patients daily activities. Recruitment of GluA2-containing Ca²⁺-impermeable AMPA receptors (CI-AMPARs) to hippocampal synaptic membrane surfaces was shown to trigger synaptic plasticity. Currently, the effect of CI-AMPAR trafficking on acute ischemic stroke remains poorly understood. β-Caryophyllene (BCP) has been shown to ameliorate cognitive impairment. However, the mechanism has not been characterized. In this study, a 60-min temporary middle cerebral artery occlusion (MCAO) model was established to simulate the pathology of acute ischemic stroke. BCP reduced neurologic deficits, cerebral infarct volume, and pathological damage in MCAO mice and caused CI-AMPARs to translocate to synaptic membranes in the hippocampus; surface expression of CI-AMPARs was also decreased in MCAO mice. Furthermore, this study also showed that BCP treatment significantly activated the cAMP/PKA pathway, which is consistent with the synaptic membrane expression of CI-AMPARs. To better understand the underlying mechanisms, the PKA inhibitor H-89 was used to study the role of BCP in MCAO mice. Interestingly, H-89 treatment significantly disrupted the BCP-mediated facilitation of CI-AMPAR translocation to the synaptic membrane surface and substantially attenuated BCP-induced protection against acute ischemic stroke. Additionally, inhibition the cAMP/PKA pathway not only reduced BCP-induced inhibition of AMPAR-mediated excitatory postsynaptic currents in the hippocampal CA1 region but also decreased the effect of BCP-mediated protection against post-acute ischemic stroke cognitive impairment. Taken together, these data indicate that PKA-dependent synaptic membrane surface recruitment of CI-AMPARs is crucial for the neuroprotective effect of BCP against acute ischemic stroke and protection against post-acute ischemic stroke cognitive impairment.

Effective-component compatibility of Bufei Yishen formula II inhibits mucus hypersecretion of chronic obstructive pulmonary disease rats by regulating EGFR/PI3K/mTOR signaling

ETHNOPHARMACOLOGICAL RELEVANCE

The effective-component compatibility of Bufei Yishen formula I (ECC-BYF I), a combination of 10 compounds, including total ginsenosides, astragaloside IV, icariin, and paeonol, etc., is derived from Bufei Yishen formula (BYF). The efficacy and safety of ECC-BYF I is equal to BYF. However, the composition of ECC-BYF I needs to be further optimized. Based on the beneficial effects of BYF and ECC-BYF I on chronic obstructive pulmonary disease (COPD), this study aimed to optimize the composition of ECC-BYF I and to explore the effects and mechanisms of optimized ECC-BYF I (ECC-BYF II) on mucus hypersecretion in COPD rats.

MATERIALS AND METHODS

ECC-BYF I was initially optimized to six groups: optimized ECC-BYF I (OECC-BYF I)-A~F. Based on a COPD rat model, the effects of OECC-BYF I-A~F on COPD rats were evaluated. R-value comprehensive evaluation was used to evaluate the optimal formula, which was named ECC-BYF II. The changes in goblet cells and expression of mucins and the mRNA and proteins involved in the epidermal growth factor receptor/phosphoinositide-3-kinase/mammalian target of rapamycin (EGFR/PI3K/mTOR) pathway were evaluated to explore the effects and mechanisms of ECC-BYF II on mucus hypersecretion.

RESULTS

ECC-BYF I and its six optimized groups, OECC-BYF I-A~F, had beneficial effects on COPD rats in improving pulmonary function and lung tissue pathology, reducing inflammation and oxidative stress, and improving the protease/anti-protease imbalance and collagen deposition. R-value comprehensive evaluation found that OECC-BYF I-E (paeonol, icariin, nobiletin, total ginsenoside, astragaloside IV) was the optimal formula for improving the comprehensive effects (lung function: V_T, MV, PEF, EF50, FVC, FEV 0.1, FEV 0.1/FVC; histological changes: MLI, MAN; IL-1β, IL-6, TNF-α, MMP-9, TIMP-1, T-AOC, LPO, MUC5AC, Collagen I and Collagen III). OECC-BYF I-E was named ECC-BYF II. Importantly, the effect of ECC-BYF II showed no significant difference from BYF and ECC-BYF I. ECC-BYF II inhibited mucus hypersecretion in COPD rats, which manifested as reducing the expression of MUC5AC and MUC5B and the hyperplasia rate of goblet cells. The mRNA and protein expression levels of EGFR, PI3K, Akt, and mTOR were increased in COPD rats and were obviously downregulated after ECC-BYF II administration.

CONCLUSION

ECC-BYF II, which consists of paeonol, icariin, nobiletin, total ginsenoside and astragaloside IV, has beneficial effects equivalent to BYF and ECC-BYF I on COPD rats. ECC-BYF II significantly inhibited mucus hypersecretion, which may be related to the regulation of the EGFR/PI3K/mTOR pathway.

Inactivation of FOXA2 by Respiratory Bacterial Pathogens and Dysregulation of Pulmonary Mucus Homeostasis

Forkhead box (FOX) proteins are transcriptional factors that regulate various cellular processes. This minireview provides an overview of FOXA2 functions, with a special emphasis on the regulation airway mucus homeostasis in both healthy and diseased lungs. FOXA2 plays crucial roles during lung morphogenesis, surfactant protein production, goblet cell differentiation and mucin expression. In healthy airways, FOXA2 exerts a tight control over goblet cell development and mucin biosynthesis. However, in diseased airways, microbial infections and proinflammatory responses deplete FOXA2 expression, resulting in uncontrolled goblet cell hyperplasia and metaplasia, mucus hypersecretion, and impaired mucociliary clearance of pathogens. Furthermore, accumulated mucus clogs the airways and creates a niche environment for persistent microbial colonization and infection, leading to acute exacerbation and deterioration of pulmonary function in patients with chronic lung diseases. Various studies have shown that FOXA2 inhibition is mediated through induction of antagonistic EGFR and IL-13R-STAT6 signaling pathways as well as through posttranslational modifications induced by microbial infections. An improved understanding of how bacterial pathogens inactivate FOXA2 may pave the way for developing therapeutics that preserve the protein's function, which in turn, will improve the mucus status and mucociliary clearance of pathogens, reduce microbial-mediated acute exacerbation and restore lung function in patients with chronic lung diseases.