Autophagy and inflammation.

Autophagy is a homeostatic mechanism involved in the disposal of damaged organelles, denatured proteins as well as invaded pathogens through a lysosomal degradation pathway. Recently, increasing evidences have demonstrated its role in both innate and adaptive immunity, and thereby influence the pathogenesis of inflammatory diseases. The detection of autophagy machinery facilitated the measurement of autophagy during physiological and pathophysiological processes. Autophagy plays critical roles in inflammation through influencing the development, homeostasis and survival of inflammatory cells, including macrophages, neutrophils and lymphocytes; effecting the transcription, processing and secretion of a number of cytokines, as well as being regulated by cytokines. Recently, autophagy-dependent mechanisms have been studied in the pathogenesis of several inflammatory diseases, including infectious diseases, Crohn's disease, cystic fibrosis, pulmonary hypertension, chronic obstructive pulmonary diseases and so on. These studies suggested that modulation of autophagy might lead to therapeutic interventions for diseases associated with inflammation. Here we highlight recent advances in investigating the roles of autophagy in inflammation as well as inflammatory diseases.

Regulatory mechanisms of TGF-ß1-induced fibrogenesis of human alveolar epithelial cells.

Pulmonary fibrosis is characterized by an extensive activation of fibrogenic cells and deposition of extracellular matrix (ECM). Transforming growth factor (TGF)-ß1 plays a pivotal role in the pathogenesis of pulmonary fibrosis, probably through the epithelial- to-mesenchymal transition (EMT) and ECM production. The present study investigates potential mechanism by which TGF-ß1 induces EMT and ECM production in the fibrogenesis of human lung epithelial cells during pulmonary fibrosis. The expression of EMT phenotype and other proteins relevant to fibrogenesis were measured and the cell bio-behaviours were assessed using Cell-IQ Alive Image Monitoring System. We found that TGF-ß1-induced EMT was accompanied with increased collagen I deposition, which may be involved in the regulation of connective tissue growth factor (CTGF) and phosphoinositide 3-kinase (PI3K) signalling pathway. Treatment with PI3K inhibitors significantly attenuated the TGF-ß1- induced EMT, CTGF expression and collagen I synthesis in lung epithelial cells. The interference of CTGF expression impaired the basal and TGF-ß1-stimulated collagen I deposition, but did not affect the process of EMT. Our data indicate that the signal pathway of TGF-ß1/PI3K/CTGF plays an important role in the fibrogenesis of human lung epithelial cells, which may be a novel therapeutic approach to prevent and treat pulmonary fibrosis.

Increased Lung Ischemia-Reperfusion Injury in Aquaporin 1-Null Mice Is Mediated via Decreased Hypoxia-Inducible Factor 2α Stability.

Aquaporin (AQP) 1, a water channel protein expressed widely in vascular endothelia, has been shown to regulate cell migration, angiogenesis, and organ regeneration. Even though its role in the pathogenesis of lung ischemia-reperfusion (IR) injury has been defined, the functional role of AQP1 during long-term IR resolution remains to be clarified. Here, we found that AQP1 expression was increased at late time points (7-14 d) after IR and colocalized with endothelial cell (EC) marker CD31. Compared with IR in wild-type mice, IR in Aqp1(-/-) mice had significantly enhanced leukocyte infiltration, collagen deposition, and microvascular permeability, as well as inhibited angiogenic factor expression. AQP1 knockdown repressed hypoxia-inducible factor (HIF)-2α protein stability. HIF-2α overexpression rescued the angiogenic factor expression in pulmonary microvascular ECs with AQP1 knockdown exposed to hypoxia-reoxygenation. Furthermore, AQP1 knockdown suppressed cellular viability and capillary tube formation, and enhanced permeability in pulmonary microvascular ECs, which were partly rescued by HIF-2α overexpression. Thus, this study demonstrates that AQP1 deficiency delays long-term IR resolution, partly through repressing angiogenesis mediated by destabilizing HIF-2α. These results suggest that AQP1 participates in long-term IR resolution, at least in part by promoting angiogenesis.

Autophagy protects against ischemia/reperfusion-induced lung injury through alleviating blood-air barrier damage.

BACKGROUND: Understanding the role and underlying regulation mechanism of autophagy in ischemia/reperfusion (I/R)-induced lung injury may provide potentially new pharmacologic targets for treatment of acute lung injury. The aim of this study was to adjust autophagy with pharmacologic agents to determine its functional significance in I/R-induced lung injury. METHODS: Human pulmonary microvascular endothelial cells (HPMVECs) and mice were pre-conditioned with autophagy inhibitor chloroquine or promoter rapamycin before they were challenged with oxygen-glucose deprivation/oxygen-glucose restoration (OGD) and lung I/R, respectively. Extracellular signal-regulated kinase (ERK)1/2 inhibitor U0126 was pre-injected into I/R-induced mice to test the role of ERK1/2 in regulating autophagy. RESULTS: OGD caused tight conjunction damage and cell death in HPMVECs, which was further aggravated by blocking autophagy, yet ameliorated through promoting autophagy. On a consistent basis, inhibiting autophagy aggravated I/R-induced lung edema and tissue inflammation, which was significantly alleviated by promoting autophagy with rapamycin. In addition, inhibition of ERK1/2 increased expression of active mammalian target-of-rapamycin and thus decreased I/R-induced autophagy. CONCLUSIONS: It appears that autophagy plays a protective role in I/R-induced lung injury and this effect may be enhanced by moderately improving autophagy level. Meanwhile, the ERK1/2 signal pathway has a positively regulating role in lung I/R-induced autophagy.

Protective effects of keratinocyte growth factor-2 on ischemia-reperfusion-induced lung injury in rats.

Ischemia-reperfusion (I/R) is a common cause to compromise tissue injury via endothelial and epithelial barrier dysfunction and damage. Keratinocyte growth factor (KGF)-2 could play an important role in the repair of alveolar epithelial damage and maintain the capillary barrier function. The present study aimed to investigate the potential effects of KGF-2 on I/R-induced lung injury in rats and the related mechanisms. KGF-2 (2.5-10 mg/kg) was administered intratracheally in rats 3 days before the left lobe with ischemia for 60 minutes followed by reperfusion for 180 minutes. Lung injury was evaluated by measuring lung morphology, blood gas analysis, total cell number, and protein concentration in the bronchoalveolar lavage fluid. The protective effects of KGF-2 on human pulmonary microvascular endothelial cells and related mechanisms were evaluated. Pretreatment with KGF-2 significantly prevented I/R-induced lung edema, inflammatory cell infiltration, protein exudation, and the release of inflammatory cytokines in rats, or I/R-induced endothelial cell apoptosis, migration, and barrier dysfunction. Phosphoinositide 3-kinase or epidermal growth factor receptor inhibitors attenuated the protective effect of KGF-2 in endothelial cells. Our results evidence that the local administration of KGF-2 may be an alternative to prophylactic or adjunct drug therapies for I/R-induced lung injury.

Genetic network and gene set enrichment analysis to identify biomarkers related to cigarette smoking and lung cancer.

OBJECTIVES: Cigarette smoking is the most demonstrated risk factor for the development of lung cancer, while the related genetic mechanisms are still unclear. METHODS: The preprocessed microarray expression dataset was downloaded from Gene Expression Omnibus database. Samples were classified according to the disease state, stage and smoking state. A new computational strategy was applied for the identification and biological interpretation of new candidate genes in lung cancer and smoking by coupling a network-based approach with gene set enrichment analysis. MEASUREMENTS: Network analysis was performed by pair-wise comparison according to the disease states (tumor or normal), smoking states (current smokers or nonsmokers or former smokers), or the disease stage (stages I-IV). The most activated metabolic pathways were identified by gene set enrichment analysis. RESULTS: Panels of top ranked gene candidates in smoking or cancer development were identified, including genes involved in cell proliferation and drug metabolism like cytochrome P450 and WW domain containing transcription regulator 1. Semaphorin 5A and protein phosphatase 1F are the common genes represented as major hubs in both the smoking and cancer related network. Six pathways, e.g. cell cycle, DNA replication, RNA transport, protein processing in endoplasmic reticulum, vascular smooth muscle contraction and endocytosis were commonly involved in smoking and lung cancer when comparing the top ten selected pathways. CONCLUSION: New approach of bioinformatics for biomarker identification and validation can probe into deep genetic relationships between cigarette smoking and lung cancer. Our studies indicate that disease-specific network biomarkers, interaction between genes/proteins, or cross-talking of pathways provide more specific values for the development of precision therapies for lung.

Effects of phosphoinositide 3-kinase on protease-induced acute and chronic lung inflammation, remodeling, and emphysema in rats.

BACKGROUND: Phosphoinositide 3-kinase (PI3K) plays an important role in tissue inflammatory reactions and fibrotic processes. The objective of this study was to evaluate the potential mechanism and therapeutic effects of PI3K inhibitor on pancreatic elastase (PE)-induced acute and chronic lung inflammation, edema, and injury. METHODS: Rats were terminated at 7 or 28 days after an intratracheal challenge with PE and intranasal instillation with a PI3K inhibitor, SHBM1009. Alterations of airway epithelial cells and myofibroblasts were studied in vitro. MEASUREMENTS: Lung inflammation, edema, and injury; emphysema; and tissue remodeling were measured after PE instillation with or without treatment with PI3K inhibitor and budesonide. Cellular biologic functions were monitored. RESULTS: SHBM1009 could prevent PE-induced acute lung inflammation, edema, and injury, and chronic lung inflammation, remodeling, and emphysema. Different patterns of inhibitory effects of SHBM1009 and BEZ235, a dual PI3K/mechanistic target of rapamycin inhibitor, on PE-challenged epithelial cells were observed. PE per se reduced epithelial cell proliferation and stability through the inhibition of cell division rather than promoting cell death, in dose- and time-dependent patterns. Effects of PI3K inhibitors on cells were associated with the severity of PE challenges. CONCLUSIONS: PI3K plays a critical role in the development of acute and chronic lung injury, including the process of tissue remodeling and emphysema. PI3K inhibitors could be new therapeutic alternatives for chronic lung diseases.

A short-term educational program improved physicians' adherence to guidelines for COPD and asthma in Shanghai.

BACKGROUND: Chronic pulmonary diseases such as chronic obstructive pulmonary disease (COPD) and asthma exert increasing burden on society while the management of them is far from adequate. The objective of this study is to evaluate adherence to guidelines through a patient study, and then investigate the effects of a short-term quality improvement educational program among clinicians in Shanghai, China. METHODS: A prescription survey was performed in a random sample of 100 COPD and asthma outpatients to assess their pharmacological therapy. Then, an educational program was conducted in young pulmonary physicians from 83 hospitals in Shanghai. The training course was divided into 7 sessions of 2 hours delivered over 4 days from July 2010 to August 2011. Three months later, all of the participants were asked to take a written examination to assess the efficiency of training. RESULTS: Prescription survey among the patients indicated the prescriptions are not consistent with the recommendations of current GOLD and GINA guidelines. The mainly existing issue is the overuse of inhaled glucocorticosteroid. For the educational program, 161 pulmonary physicians have attended the training course, and 110 clinicians finished the tests with an attendance rate of 68.3%. Although most of the clinicians recognized the increasing burden of COPD and asthma, they do not know well about the core elements of guidelines and their clinical practice is not fully in agreement with current recommendations. Through crossover comparison, our results suggested clinicians' knowledge of the guidelines was improved after training. CONCLUSIONS: We concluded that application of continuous educational programs among physicians might promote their adherence to guidelines, and by that improve the quality of healthcare.

Bioinformatics insights into acute lung injury/acute respiratory distress syndrome.

Bioinformatics is the application of omics science, information technology, mathematics and statistics in the field of biomarker detection. Clinical bioinformatics can be applied for identification and validation of new biomarkers to improve current methods of monitoring disease activity and identify new therapeutic targets. Acute lung injurt (ALI)/Acute respiratory distress syndrome (ARDS) affects a large number of patients with a poor prognosis. The present review mainly focused on the progress in understanding disease heterogeneity through the use of evolving biological, genomic, and genetic approaches and the role of clinical bioinformatics in the pathogenesis and treatment of ALI/ARDS. The remarkable advances in clinical bioinformatics can be a new way for understanding disease pathogenesis, diagnosis and treatment.

Profiling the human response to physical exercise: a computational strategy for the identification and kinetic analysis of metabolic biomarkers.

BACKGROUND: In metabolomics, biomarker discovery is a highly data driven process and requires sophisticated computational methods for the search and prioritization of novel and unforeseen biomarkers in data, typically gathered in preclinical or clinical studies. In particular, the discovery of biomarker candidates from longitudinal cohort studies is crucial for kinetic analysis to better understand complex metabolic processes in the organism during physical activity. FINDINGS: In this work we introduce a novel computational strategy that allows to identify and study kinetic changes of putative biomarkers using targeted MS/MS profiling data from time series cohort studies or other cross-over designs. We propose a prioritization model with the objective of classifying biomarker candidates according to their discriminatory ability and couple this discovery step with a novel network-based approach to visualize, review and interpret key metabolites and their dynamic interactions within the network. The application of our method on longitudinal stress test data revealed a panel of metabolic signatures, i.e., lactate, alanine, glycine and the short-chain fatty acids C2 and C3 in trained and physically fit persons during bicycle exercise. CONCLUSIONS: We propose a new computational method for the discovery of new signatures in dynamic metabolic profiling data which revealed known and unexpected candidate biomarkers in physical activity. Many of them could be verified and confirmed by literature. Our computational approach is freely available as R package termed BiomarkeR under LGPL via CRAN http://cran.r-project.org/web/packages/BiomarkeR/.

Preventive and therapeutic effects of phosphoinositide 3-kinase inhibitors on acute lung injury.

BACKGROUND: Phosphoinositide 3-kinases (PI3Ks) are involved in a number of biologic responses. Recent preclinical studies demonstrated that the PI3K-dominant signal pathway could play an important role in the development of acute lung injury, although the mechanism remains unclear. METHODS: CD-1 mice were administered different PI3K inhibitors either intranasally or intragastrically once a day for 3 days before intratracheal instillation of lipopolysaccharide at 4 h and 24 h. Effects of SHBM1009 on lipopolysaccharide-induced capillary permeability, leukocyte distribution and activation, and epithelial cell function were measured. Therapeutic effects of SHBM1009 on pancreatic elastase-induced lung injury were evaluated in rats. RESULTS: The data demonstrated that the local delivery of PI3K inhibitors played more effective roles in the prevention of endotoxin-induced lung injury than the systemic delivery. The preventive effects of PI3K inhibitors varied most likely because of chemical properties, targeting sites, and pharmacokinetics. The local PI3K inhibitors prevented both endotoxin- and elastase-induced lung injury in mice and rats, possibly through directly inhibiting or inactivating the function of airway epithelial cells, which could not produce chemoattractant factors to activate neutrophils and macrophages. CONCLUSIONS: PI3K may be a therapeutic target for lung injury, and local delivery of PI3K inhibitors may be one of the optimal approaches for the therapy.

COPD in China: the burden and importance of proper management.

Although, to our knowledge, there has been no exhaustive or credible review of the evidence of the disease burden of COPD in China, COPD has become an increasing public health concern to the Chinese medical community. The purpose of this article is to review the evidence and evaluate and clarify the disease burden of COPD in China with the aim of improving effective management. We reviewed previous studies of COPD in China, which included data on prevalence, mortality, disease burden, risk factors, diagnosis, and management by searching related Web sites, including PubMed, ProQuest, and Thomson Reuters' Web of Knowledge, as well as major Chinese databases and government Web sites. Reported COPD prevalence varied between 5% and 13% in different provinces/cities across China. In 2008, COPD ranked fourth as a leading cause of death in urban areas and third in rural areas. In addition, COPD accounted for 1.6% of all hospital admissions in China in that year. The high prevalence of smoking and biomass fuel use acted as major contributors to the high occurrence of COPD in China. Management of COPD in China should focus on adjusting the distribution of medical resources and on addressing public health policies to facilitate earlier diagnosis in rural areas, aim to reduce smoking prevalence, improve patients' self-management, and keep physicians' knowledge up to date and consistent with current guidelines. COPD is one of the most challenging medical issues facing China because of its influence on both personal and public health and its impact on the economy. Optimal management strategies should be adopted and strengthened immediately.

Involvement of type II pneumocytes in the pathogenesis of chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality, but the cellular and molecular mechanisms are still not fully understood. Type II pneumocytes are identified as the synthesizing cells of the alveolar surfactant, which has important properties in maintaining alveolar and airway stability. Lung surfactant can reduce the surface tension and prevent alveolar collapse and the airway walls collapse. Pulmonary surfactant components play important roles in normal lung function and inflammation in the lung. Surfactant has furthermore been shown to modulate the process of innate host defense, including suppression of cytokine secretion and transcription factor activation, in the inflammatory network of COPD. Abnormalities of lung surfactant might be one of the mechanisms leading to increased airway resistance in COPD. The increased expression of Granzyme A and B was found in lung tissues of patients with COPD and type II pneumocytes was proposed to be involved in the pathogenesis of COPD. These novel findings provide new sights into the role of the type II pneumocytes in the pathogenesis of COPD.

Potential clinical application of KGF-2 (FGF-10) for acute lung injury/acute respiratory distress syndrome.

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is an acute life-threatening form of hypoxemic respiratory failure with a high mortality rate, and there is still a great need for more effective therapies for such a severe and lethal disease. Dysfunction of endothelial and epithelial barriers is one of the most important mechanisms in hypoxia-associated ALI/ARDS. The acceleration of the epithelial repair process in the injured lung may provide an effective therapeutic target. KGF-2, a potent alveolar epithelial cell mitogen, plays an important role in organ morphogenesis and epithelial differentiation, and modulates a variety of mechanisms recognized to be important in alveolar repair and resolution in ALI/ARDS. Preclinical and clinical studies have suggested that KGF-2 may be the candidate of novel therapies for alveolar epithelial damage during ALI/ARDS.