PKM2 regulates cigarette smoke-induced airway inflammation and epithelial-to-mesenchymal transition via modulating PINK1/Parkin-mediated mitophagy.

Cigarette smoke (CS) mediates inflammation and epithelial-mesenchymal transition (EMT) in bronchial epithelial cells, contributing to airway remodeling in chronic obstructive pulmonary disease (COPD). Cross-talk between metabolic pathways and cell signaling has emerged as an important focus of research in the field of inflammation. Here, we established in vitro and in vivo models of CS-induced COPD to elucidate the role of pyruvate kinase M2 (PKM2), a glycolytic enzyme, in CS-induced airway remodeling. Exposure to CS significantly increased PKM2 expression in lung tissues of C57BL/6 mice and BEAS-2B cells, which positively related to the levels of airway inflammation and EMT. Administering PKM2 inhibitor shikonin attenuated CS-induced airway inflammation and EMT process. Moreover, knockdown of PKM2 by small-interfering RNA (siRNA) decreased the release of TNF-α and IL-8, ROS and reversed the CS extract (CSE)-induced changes of N-cadherin and E-cadherin in BEAS-2B cells. In CSE-treated cells, we also observed enhancement of PINK1/Parkin-mediated mitophagy, which were decreased by PKM2 siRNA. Furthermore, pretreatment with mitophagy inducer CCCP before CSE stimulation led to increased expressions of both nuclear and cytosolic PKM2, accompanied by reduction of TGF-ß-induced factor homeobox 2 (TGIF2), a repressor of TGF-ß1/smad pathway and EMT, while PKM2 knockdown restored the expression of TGIF2. Our results imply that CS induces PKM2 upregulation in airway epithelial cells, acting in synergism with PINK/Parkin-mediated mitophagy, which may initiate and exaggerate airway inflammation and EMT process. Further studies will be required to elucidate more molecular details and other pathways by which PKM2-mitophagy signaling regulates the effector function of airway epithelial.

Astrocyte secretes IL-6 to modulate PSD-95 palmitoylation in basolateral amygdala and depression-like behaviors induced by peripheral nerve injury.

Dysfunction of glutamatergic synaptic plasticity in basolateral amygdala (BLA) constitutes a critical pathogenic mechanism underlying the depression-like behaviors induced by chronic pain. Astrocytes serve as an important supporting cell modulating glutamatergic synaptic transmission. Here, we found that peripheral spared nerve injury (SNI) induced astrocyte activation to release IL-6 in BLA. Inhibition of astrocyte activity attenuated SNI-induced IL-6 overexpression and depression-like behaviors. Moreover, SNI enhanced the abundance of DHHC2 in synaptosome and DHHC3 in Golgi apparatus, promoted PSD-95 palmitoylation, and increased the recruitment of GluR1 and NR2B at synapses. Suppression of IL-6 or PSD-95 palmitoylation attenuated the synaptic accumulation of GluR1 and NR2B in BLA and improved depression-like behaviors induced by SNI. Furthermore, IL-6 downstream PI3K increased the expression of DHHC3 in Golgi apparatus and facilitated the interaction of palmitoylated PSD-95 with GluR1 and NR2B at synapses. These findings collectively suggested that SNI activated astrocyte to release IL-6 in BLA, which promoted PSD-95 palmitoylation and enhanced the synaptic trafficking of GluR1 and NR2B, and subsequently mediated the depression-like behaviors induced by nerve injury.

DKK1 Positively Correlates with Lung Function in COPD Patients and Reduces Airway Inflammation.

PURPOSE: WNT/ß-catenin signal pathway is a potential hope for lung tissue repair. We investigated the levels of Dickkopf-1 (DKK1), an endogenous inhibitor of WNT/ß-catenin signal pathway, in chronic obstructive pulmonary disease (COPD) patients and airway inflammation. PATIENTS AND METHODS: Collected the demographic and clinical characteristics of 36 healthy controls, 25 stable COPD patients and 10 acute exacerbation of COPD (AECOPD) patients, then performed pulmonary function and detected serum DKK1 levels. After over-expression of DKK1, detect the levels of DDK1, lipoprotein-related protein 6 (LRP6) and inflammatory factors in bronchial epithelial cells stimulated with cigarette smoke extract (CSE). RESULTS: Serum DKK1 were reduced in stable COPD patients compared to healthy controls (3866.72 ± 775.33 pg/mL vs 5317.61 ± 1317.20 pg/mL, p<0.0001), but there was no significant difference between stable and acutely exacerbated patients (3866.72 ± 775.33 pg/mL vs 3482.10 ± 841.25 pg/mL, p>0.05). DKK1 was positively correlated with FEV1 (r = 0.570, p<0.0001), FEV1/FVC (rho = 0.590, p<0.0001), FEV1/Pre (r = 0.517, p<0.0001). Multiple linear regression analysis also suggested that FEV1 levels were higher with increasing DKK1. In vitro, elevated IL-6, IL-8, TNF-α and decreased DKK1, LRP6 were found in Beas-2B cells after CSE treatments, and increased LRP6 and decreased inflammatory factors were found after overexpression of DKK1. Andrographolide restored the CSE-induced decrease in DKK1 and increase in IL-6 and IL-8. CONCLUSION: DKK1 levels were decreased in COPD patients and positively correlated with lung function, overexpression of DKK1 and andrographolide attenuated airway cell inflammation, both suggesting a potential role in pathophysiology and providing a disease-specific biomarker pattern.

Mitochondrial Damage-Associated Molecular Patterns Exacerbate Lung Fluid Imbalance Via the Formyl Peptide Receptor-1 Signaling Pathway in Acute Lung Injury.

OBJECTIVES: To investigate the effect of mitochondrial damage-associated molecular patterns on the lung fluid homeostasis in experimental acute lung injury. DESIGN: Experimental study. SETTING: Research laboratory. SUBJECTS: Patients with acute respiratory distress syndrome and control subjects, wild-type C57BL/6 and formyl peptide receptor-1 gene knockout mice, and primary rat alveolar epithelial type II cells. INTERVENTIONS: Samples of bronchoalveolar lavage fluid and serum were obtained from patients and control subjects. Mice were intratracheally instilled with lipopolysaccharide and mitochondrial damage-associated molecular patterns. The primary rat alveolar epithelial type II cells were isolated and incubated with mitochondrial damage-associated molecular patterns. MEASUREMENTS AND MAIN RESULTS: Patients were divided into direct (pulmonary) and indirect (extrapulmonary) injury groups based on etiology. The release of mitochondrial peptide nicotinamide adenine dinucleotide dehydrogenase 1 in both bronchoalveolar lavage fluid and serum was induced in patients and was associated with etiology. In the lipopolysaccharide-induced lung injury, administration of mitochondrial damage-associated molecular patterns exacerbated the lung fluid imbalance, which was mitigated in formyl peptide receptor-1 knockout mice. Proteomic analysis of mouse lung tissues revealed the involvement of ion channels and tight junction proteins in this process. Treatment with mitochondrial damage-associated molecular patterns decreased the expression of epithelial sodium channel α, zonula occludens-1, and occludin via the formyl peptide receptor-1/p38 pathway in the primary rat alveolar epithelial type II cells. CONCLUSIONS: Mitochondrial damage-associated molecular patterns exacerbate lung fluid imbalance in the experimental acute lung injury model through formyl peptide receptor-1 signaling, the inhibition of which may prevent exacerbation of lung fluid imbalance induced by mitochondrial damage-associated molecular patterns. Thus, formyl peptide receptor-1 is a potential therapeutic target for acute respiratory distress syndrome.

The Association and Influencing Factors between Antipsychotics Exposure and the Risk of VTE and PE: A Systematic Review and Meta-analysis.

BACKGROUND: Different clinical studies have given inconsistent results on whether the use of antipsychotics increases the risk of thromboembolism. In this paper, we reviewed all relevant literature to provide suggestions for clinical diagnosis and treatment. METHODS: PubMed, Web of Science, EMBASE, MEDLINE, Cochrane and Scopus databases were thoroughly searched up to June 2019. Two researchers independently searched the literature, extracted data. Data were analyzed by Stata 12.0 software. RESULTS: A total of 22 studies involving 31514226 subjects were included. This meta-analysis showed that patients taking the first- or second-generation antipsychotics had a higher risk of venous thromboembolism and pulmonary embolism than those who did not, and low potency first-generation agents increased the risk of venous thromboembolism more than high potency antipsychotics, and olanzapine, clozapine, haloperidol, perphenazine and risperidone also significantly increased the risk of it. The risk of venous thrombosis in obese people was higher than that in overweight people, patients not less than 65 years old had an increased risk compared with younger patients. In addition, women taking antipsychotics had a higher risk of pulmonary embolism than men. CONCLUSION: The use of antipsychotics will increase the risk of venous thromboembolism and pulmonary embolism, which will be affected by the type of antipsychotics and patient characteristics.

Diagnostic accuracy of E-cadherin for malignanteffusions: a systematic review and meta-analysis.

BACKGROUND: The differential diagnosis of malignant effusion remains a clinical challenge. We aim to summarise all relevant literature studies in order to determine the overall clinical value of E-cadherin in the diagnosis of malignant effusion by meta-analysis. METHODS: PubMed, the Cochrane Library Database, Medline (Ovid), Web of Science, CNKI, WANFANG and WEIPU databases are thoroughly searched up to 15 March2018. The calculated pooled sensitivity, specificity, likelihood ratio (LR), diagnostic OR(DOR) and the summary receiver operating characteristic (SROC) curve were plotted. RESULTS: A total of 15 studies were included in the analysis. The sensitivity and specificity of E-cadherin in the diagnosis of malignant effusion were determined to be high, with a sensitivity of 0.83(95%CI0.79 to 0.87) and a specificity of 0.96(95%CI0.90 to 0.98). The positive LR was determined to be 21.10(95%CI 8.54 to 52.11), the negative LR was determined to be 0.17(95% CI 0.14 to 0.22) and the DOR was determined to be 121.34(95%CI 49.11 to 299.80). The SROC curve exhibited a high overall diagnostic, with the area under the curve measured to be 0.91(95% CI 0.89 to 0.93). Subgroup analysis showed the method (cell blocks or smears), sample size (≥100 or<100), geographical location (Asia, Europe or USA) and impact factor of each article (≥3 or<3) were not the sources of overall heterogeneity. CONCLUSION: E-cadherin exhibits very good diagnostic accuracy for the diagnosis for malignant effusion; thus, it can be helpful in the process of clinical decisions.

The elevated CXCL5 levels in circulation are associated with lung function decline in COPD patients and cigarette smoking-induced mouse model of COPD.

Introduction: C-X-C motif chemokine 5 is primarily chemotactic for neutrophils and previously shown to increase in the bronchoalveolar lavage fluid of patients with chronic obstructive pulmonary disease. However, whether C-X-C motif chemokine 5 levels correlate with lung function decline in patients or mouse model of chronic obstructive pulmonary disease was not clear. Methods: The mouse model was induced by cigarette smoke exposure. Plasma/serum and bronchoalveolar lavage fluid were obtained from patients and mouse model of chronic obstructive pulmonary disease; C-X-C motif chemokine 5 levels were assessed and correlated with lung functions and granulocyte-colony stimulating factor levels, respectively. Results: The C-X-C motif chemokine 5 levels increased and correlated to granulocyte-colony stimulating factor levels in both plasma/serum and bronchoalveolar lavage fluid obtained from patients and mouse model of chronic obstructive pulmonary disease. Circulating levels of C-X-C motif chemokine 5 correlated to lung functions decline in patients and mouse model. Conclusions: Granulocyte-colony stimulating factor might coordinate with C-X-C motif chemokine 5 in the pathogenesis of neutrophilic inflammation in chronic obstructive pulmonary disease. Circulating C-X-C motif chemokine 5 might serve as a potential blood-based biomarker to add additional modest predictive value on the preliminary screening and diagnosis of chronic obstructive pulmonary disease. Key messages Circulating C-X-C motif chemokine 5 might serve as a potential blood-based biomarker to add additional modest predictive value on the preliminary screening and diagnosis of COPD. Granulocyte-colony stimulating factor might coordinate with C-X-C motif chemokine 5 in the pathogenesis of neutrophilic inflammation in chronic obstructive pulmonary disease.

The association of elevated circulating endocan levels with lung function decline in COPD patients.

BACKGROUND: Endocan is thought to be a novel inflammatory marker that is associated with a variety of inflammatory diseases. However, its role in the pathogenesis of COPD remains unclear. This study aims to explore the potential role of endocan in COPD. METHODS: In total, 27 healthy volunteers, 55 COPD patients and 36 acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients were included in the study. Basic demographic characteristics, clinical features and blood samples were collected. Magnetic luminex screening assays were used to detect the concentration of endocan, Fas and Fas ligand (Fas-L) in plasma. Differences between groups were compared using an Independent sample t-test, Welch's t-test, chi-squared test and Wilcoxon rank sum test. The correlations of plasma endocan with lung function parameters, Fas and Fas-L were analyzed by Pearson's partial correlation test (adjusted for age, gender, body mass index and smoking history) and multiple linear regression. RESULTS: Plasma endocan levels in COPD patients were significantly higher than those in healthy volunteers (509.7±18.25 pg/mL vs 434.8±18.98 pg/mL (P=0.0124)), and AECOPD patients had the highest levels of endocan (524.7±27.18 pg/mL). Correlation analysis showed that circulating endocan had a negative correlation to FEV1/FVC, FEV1/predictive and FVC (adjusted r=-0.213, P=0.03; adjusted r=-0.209, P=0.034; and adjusted r=-0.300, P=0.002, respectively), and had a positive correlation to Fas (adjusted r=0.280, P=0.004). CONCLUSION: Our study shows that elevated circulating endocan levels are associated with reduced lung ventilation function in COPD and AECOPD patients. In addition, endocan may influence apoptosis in COPD, suggesting that endocan may play a role in COPD pathogenesis.

Mitochondrial peptides cause proinflammatory responses in the alveolar epithelium via FPR-1, MAPKs, and AKT: a potential mechanism involved in acute lung injury.

Acute lung injury (ALI) is characterized by alveolar epithelial damage and uncontrolled pulmonary inflammation. Mitochondrial damage-associated molecular patterns (DAMPs), including mitochondrial peptides [ N-formyl peptides (NFPs)], are released during cell injury and death and induce inflammation by unclear mechanisms. In this study, we have investigated the role of mitochondrial DAMPs (MTDs), especially NFPs, in alveolar epithelial injury and lung inflammation. In murine models of ALI, high levels of mitochondrial NADH dehydrogenase 1 in bronchoalveolar lavage fluid (BALF) were associated with lung injury scores and increased formyl peptide receptor (FPR)-1 expression in the alveolar epithelium. Cyclosporin H (CsH), a specific inhibitor of FPR1, inhibited lung inflammation in the ALI models. Both MTDs and NFPs upon intratracheal challenge caused accumulation of neutrophils into the alveolar space with elevated BALF levels of mouse chemokine KC, interleukin-1ß, and nitric oxide and increased pulmonary FPR-1 levels. CsH significantly attenuated MTDs or NFP-induced inflammatory lung injury and activation of MAPK and AKT pathways. FPR1 expression was present in rat primary alveolar epithelial type II cells (AECIIs) and was increased by MTDs. CsH inhibited MTDs or NFP-induced CINC-1/IL-8 release and phosphorylation of p38, JNK, and AKT in rat AECII and human cell line A549. Inhibitors of MAPKs and AKT also suppressed MTD-induced IL-8 release and NF-κB activation. Collectively, our data indicate an important role of the alveolar epithelium in initiating immune responses to MTDs released during ALI. The potential mechanism may involve increase of IL-8 production in MTD-activated AECII through FPR-1 and its downstream MAPKs, AKT, and NF-κB pathways.

Effects of calcium gluconate on lipopolysaccharide-induced acute lung injury in mice.

Lipopolysaccharide (LPS), which can cause acute airway inflammatory reactions, constitutes one of the most common substances to establish acute lung injury (ALI) models in mice. Studies suggest that calcium gluconate offers the possibility of suppressing the immune response, and this study was intended to explore the effects of calcium gluconate on LPS-induced ALI in mice. Mice inhaled with LPS were intraperitoneally injected with calcium gluconate (12.5, 25, 50 mg/kg). IL-1ß, IL-6 and TNF-α levels in bronchoalveolar lavage fluid (BALF) were determined by ELISA. The expression of signaling proteins, phosphorylation extracellular regulated protein kinases (p-ERK), was detected using Western Blot in lung tissues. In our study, the release of inflammatory cytokines IL-1ß, IL-6 and TNF-α in BALF increased after inhalation of LPS. Post-treatment with calcium gluconate inhibited LPS-induced airway inflammatory injury and the release of inflammatory cytokines. In addition, LPS promoted the expression of signaling protein p-ERK while calcium gluconate was capable of reversing this change. Overall, calcium gluconate inhibits LPS-induced ALI in mice, which may take effects through the inhibition of ERK phosphorylation.

Role of Receptor for Advanced Glycation End Products in Regulating Lung Fluid Balance in Lipopolysaccharide-induced Acute Lung Injury and Infection-Related Acute Respiratory Distress Syndrome.

Receptor for advanced glycation end products (RAGE) is implicated in inflammatory responses in acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), but its role in pulmonary edema formation remains unclear, especially in infection-related ARDS mainly caused by pneumonia or sepsis. In this study, we investigated the role of RAGE in alveolar fluid regulation by using RAGE gene knockout (RAGE) mice in a murine ALI model induced by lipopolysaccharide (LPS), and by comparing soluble RAGE (sRAGE) levels in serum and bronchial alveolar lavage fluid between ARDS patients and control subjects. We found that RAGE knockout significantly improved alveolar fluid clearance and reduced pulmonary vascular albumin leakage upon LPS challenge. Furthermore, LPS-induced substantial decrease in lung expression of sodium-potassium ATPase (Na,K-ATPase), epithelial sodium channel, and zonula occluden-1 (ZO-1) were fully or partially restored by the deletion of RAGE. In addition to this, LPS-induced lung leukocyte infiltration and inflammatory cytokine and chemokine release were all attenuated in RAGE mice as compared to wide-type mice. In infection-related ARDS patients, both serum and bronchial alveolar lavage fluid levels of the sRAGE were much higher than those in control subjects, and they were positively correlated with pulmonary vascular permeability and levels of interleukin (IL)-6, IL-8, and macrophage inflammatory protein (MIP)-2. Taken together, we provided the first direct evidence for the essential role of RAGE in regulating lung fluid balance in infection-related ARDS/ALI. The underlying mechanisms may involve the downregulation of both ion-channel and tight junction proteins mediated by RAGE signaling in bacterial endotoxin-induced lung injury.