Enhancing knowledge mastery in resident students through peer-teaching: a study in respiratory medicine.

AIM: The transition from medical students to competent physicians requires comprehensive training during residency programs. In China, resident students typically undergo 2- or 3-year training programs. While they learn from patient interactions under the guidance of experienced doctors, integrating theoretical knowledge from textbooks into practical cases remains a challenge. This study aimed to explore the impact of medical interns acting as peer-students on the knowledge mastery of resident students. METHOD: The participants of this study consisted of resident students specializing in respiratory medicine at the Second Affiliated Hospital of Zhejiang University, School of Medicine. Resident students were given the opportunity to volunteer as peer-teachers for medical interns in the respiratory department. Those who chose to instruct interns were automatically placed into the test group, while those who opted not to partake in intern instruction formed the control group. In their role as peer-teachers, resident students assumed the responsibility of guiding interns in patient management throughout the entire continuum, spanning from initial engagement to discharge, a commitment that extended over a minimum period of 2 weeks. The resident students' academic performance was evaluated through a departmental examination consisting of 50 multiple-choice questions, which was administered upon completing their rotation. Statistical analysis was performed to assess the impact of peer-teaching on the resident students' performance. RESULTS: Between January 2023 and June 2023, a total of 158 resident students completed their rotation in the respiratory department. Among them, 40 resident students willingly took on the responsibility of instructing medical interns, while 118 resident students did not participate in intern teaching. With a "one-to-one" teaching policy in place, the overall satisfaction rate of the interns was an impressive 95.35%. Pre-rotation test scores for the test group averaged 81.66 ± 8.325 (Mean ± SD) and the control group averaged 81.66 ± 8.002, without significance. The departmental examination scores of the test group averaged 85.60 ± 7.886, while the control group scored an average of 82.25 ± 8.292, with a statistically significant difference (p = 0.027). CONCLUSION: In conclusion, our study underscores the positive influence of peer-teaching on the knowledge mastery of resident students.

Bronchoalveolar lavage fluid polymerase chain reaction for invasive pulmonary aspergillosis among high-risk patients: a diagnostic meta-analysis.

BACKGROUND: Polymerase chain reaction (PCR) assays are perceived to facilitate the diagnosis of fungal infections. However, due to lack of standardization, the value of bronchoalveolar lavage (BAL) fluid PCR in diagnosis of invasive pulmonary aspergillosis (IPA) remains unclear. METHODS: We conducted a systematic meta-analysis to evaluate the accuracy of BAL fluid PCR in IPA diagnosis among high-risk patients. All studies involving patients at risk for IPA were included. The sensitivity, specificity, positive and negative likelihood ratios of BAL fluid PCR were summarized for diagnosis of proven/probable IPA, or proven IPA only. Potential heterogeneity was assessed by subgroup analyses and meta-regression. RESULTS: Forty-one studies involving 5668 patients were analyzed. The summary sensitivity, specificity, positive and negative likelihood ratios of BAL fluid PCR for proven/probable IPA were 0.75 (95% CI = 0.67-0.81), 0.94 (95% CI = 0.90-0.96), 11.8 (95% CI = 7.7-18.1) and 0.27 (95% CI = 0.20-0.36), respectively. Whereas for proven IPA only, sensitivity and specificity were 0.91 (95% CI = 0.68-0.98) and 0.80 (95% CI = 0.74-0.85) in fourteen studies involving 2061 patients. Significant heterogeneity was present due to the underlying disease, antifungal treatment and differences in DNA extraction techniques and choice of PCR assay. Compared to patients with hematological malignancies (HM) and hematopoietic stem cell/solid organ transplantation (HSCT/SOT), sensitivity was higher in the population with disease such as chronic obstructive pulmonary disease, solid tumor, autoimmune disease with prolonged use of corticosteroids, etc. (0.88 vs. 0.68, P < 0.001), which was related to the concurrent use of antifungal prophylaxis among patients with HM and HSCT/SOT. CONCLUSION: BAL fluid PCR is a useful diagnostic tool for IPA in immunocompromised patients and is also effective for diagnosing IPA in patients without HM and HSCT/SOT. Furthermore, standard protocols for DNA extraction and PCR assays should be focused on to improve the diagnostic accuracy. Trial registration PROSPERO, registration number CRD42021239028.

Airway Epithelial cGAS Is Critical for Induction of Experimental Allergic Airway Inflammation.

DNA damage could lead to the accumulation of cytosolic DNA, and the cytosolic DNA-sensing pathway has been implicated in multiple inflammatory diseases. However, the role of cytosolic DNA-sensing pathway in asthma pathogenesis is still unclear. This article explored the role of airway epithelial cyclic GMP-AMP synthase (cGAS), the major sensor of cytosolic dsDNA, in asthma pathogenesis. Cytosolic dsDNA accumulation in airway epithelial cells (ECs) was detected in the setting of allergic inflammation both in vitro and in vivo. Mice with cGAS deletion in airway ECs were used for OVA- or house dust mite (HDM)-induced allergic airway inflammation. Additionally, the effects of cGAS knockdown on IL-33-induced GM-CSF production and the mechanisms by which IL-33 induced cytosolic dsDNA accumulation in human bronchial epithelial (HBE) cells were explored. Increased accumulation of cytosolic dsDNA was observed in airway epithelium of OVA- or HDM-challenged mice and in HBE cells treated with IL-33. Deletion of cGAS in the airway ECs of mice significantly attenuated the allergic airway inflammation induced by OVA or HDM. Mechanistically, cGAS participates in promoting TH2 immunity likely via regulating the production of airway epithelial GM-CSF. Furthermore, Mito-TEMPO could reduce IL-33-induced cytoplasmic dsDNA accumulation in HBE cells possibly through suppressing the release of mitochondrial DNA into the cytosol. In conclusion, airway epithelial cGAS plays an important role via sensing the cytosolic dsDNA in asthma pathogenesis and could serve as a promising therapeutic target against allergic airway inflammation.

Application of a classifier combining bronchial transcriptomics and chest computed tomography features facilitates the diagnostic evaluation of lung cancer in smokers and nonsmokers.

Lung cancer screening by computed tomography (CT) reduces mortality but exhibited high false-positive rates. We established a diagnostic classifier combining chest CT features with bronchial transcriptomics. Patients with CT-detected suspected lung cancer were enrolled. The sample collected by bronchial brushing was used for RNA sequencing. The e1071 and pROC packages in R software was applied to build the model. Eventually, a total of 283 patients, including 183 with lung cancer and 100 with benign lesions, were included into final analysis. When incorporating transcriptomic data with radiological characteristics, the advanced model yielded 0.903 AUC with 81.1% NPV. Moreover, the classifier performed well regardless of lesion size, location, stage, histologic type or smoking status. Pathway analysis showed enhanced epithelial differentiation, tumor metastasis, and impaired immunity were predominant in smokers with cancer, whereas tumorigenesis played a central role in nonsmokers with cancer. Apoptosis and oxidative stress contributed critically in metastatic lung cancer; by contrast, immune dysfunction was pivotal in locally advanced lung cancer. Collectively, we devised a minimal-to-noninvasive, efficient diagnostic classifier for smokers and nonsmokers with lung cancer, which provides evidence for different mechanisms of cancer development and metastasis associated with smoking. A negative classifier result will help the physician make conservative diagnostic decisions.

MTOR suppresses autophagy-mediated production of IL25 in allergic airway inflammation.

INTRODUCTION: Airway epithelial cells are recognised as an essential controller for the initiation and perpetuation of asthmatic inflammation, yet the detailed mechanisms remain largely unknown. This study aims to investigate the roles and mechanisms of the mechanistic target of rapamycin (MTOR)-autophagy axis in airway epithelial injury in asthma. METHODS: We examined the MTOR-autophagy signalling in airway epithelium from asthmatic patients or allergic mice induced by ovalbumin or house dust mites, or in human bronchial epithelial (HBE) cells. Furthermore, mice with specific MTOR knockdown in airway epithelium and autophagy-related lc3b-/- mice were used for allergic models. RESULTS: MTOR activity was decreased, while autophagy was elevated, in airway epithelium from asthmatic patients or allergic mice, or in HBE cells treated with IL33 or IL13. These changes were associated with upstream tuberous sclerosis protein 2 signalling. Specific MTOR knockdown in mouse bronchial epithelium augmented, while LC3B deletion diminished allergen-induced airway inflammation and mucus hyperproduction. The worsened inflammation caused by MTOR deficiency was also ameliorated in lc3b-/- mice. Mechanistically, autophagy was induced later than the emergence of allergen-initiated inflammation, particularly IL33 expression. MTOR deficiency increased, while knocking out of LC3B abolished the production of IL25 and the eventual airway inflammation on allergen challenge. Blocking IL25 markedly attenuated the exacerbated airway inflammation in MTOR-deficiency mice. CONCLUSION: Collectively, these results demonstrate that allergen-initiated inflammation suppresses MTOR and induces autophagy in airway epithelial cells, which results in the production of certain proallergic cytokines such as IL25, further promoting the type 2 response and eventually perpetuating airway inflammation in asthma.

Cigarette smoke-initiated autoimmunity facilitates sensitisation to elastin-induced COPD-like pathologies in mice.

It is currently not understood whether cigarette smoke exposure facilitates sensitisation to self-antigens and whether ensuing auto-reactive T cells drive chronic obstructive pulmonary disease (COPD)-associated pathologies.To address this question, mice were exposed to cigarette smoke for 2 weeks. Following a 2-week period of rest, mice were challenged intratracheally with elastin for 3 days or 1 month. Rag1-/- , Mmp12-/- , and Il17a-/- mice and neutralising antibodies against active elastin fragments were used for mechanistic investigations. Human GVAPGVGVAPGV/HLA-A*02:01 tetramer was synthesised to assess the presence of elastin-specific T cells in patients with COPD.We observed that 2 weeks of cigarette smoke exposure induced an elastin-specific T cell response that led to neutrophilic airway inflammation and mucus hyperproduction following elastin recall challenge. Repeated elastin challenge for 1 month resulted in airway remodelling, lung function decline and airspace enlargement. Elastin-specific T cell recall responses were dose dependent and memory lasted for over 6 months. Adoptive T cell transfer and studies in T cells deficient Rag1-/- mice conclusively implicated T cells in these processes. Mechanistically, cigarette smoke exposure-induced elastin-specific T cell responses were matrix metalloproteinase (MMP)12-dependent, while the ensuing immune inflammatory processes were interleukin 17A-driven. Anti-elastin antibodies and T cells specific for elastin peptides were increased in patients with COPD.These data demonstrate that MMP12-generated elastin fragments serve as a self-antigen and drive the cigarette smoke-induced autoimmune processes in mice that result in a bronchitis-like phenotype and airspace enlargement. The study provides proof of concept of cigarette smoke-induced autoimmune processes and may serve as a novel mouse model of COPD.

Proteomic analysis of sputum reveals novel biomarkers for various presentations of asthma.

BACKGROUND: It is now recognized that asthma can present in different forms. Typically, asthma present with symptoms of wheeze, breathlessness and cough. Atypical forms of asthma such as cough variant asthma (CVA) or chest tightness variant asthma (CTVA) do not wheeze. We hypothesize that these different forms of asthma may have distinctive cellular and molecular features. METHODS: 30 patients with typical or classical asthma (CA), 27 patients with CVA, 30 patients with CTVA, and 30 healthy control adults were enrolled in this prospective study. We measured serum IgE, lung function, sputum eosinophils, nitric oxide in exhaled breath (FeNO). We performed proteomic analysis of induced-sputum supernatants by mass spectrometry. RESULTS: There were no significant differences in atopy and FEV1 among patients with CA, CVA, and CTVA. Serum IgE, sputum eosinophil percentages, FeNO, anxiety and depression scores were significantly increased in the three presentations of asthmatic patients as compared with healthy controls but there was no difference between the asthmatic groups. Comprehensive mass spectrometric analysis revealed more than a thousand proteins in the sputum from patients with CA, CVA, and CTVA, among which 23 secreted proteins were higher in patients than that in controls. CONCLUSIONS: Patients with CA, CVA, or CTVA share common clinical characteristics of eosinophilic airway inflammation. And more importantly, their sputum samples were composed with common factors with minor distinctions. These findings support the concept that these three different presentations of asthma have similar pathogenetic mechanism in terms of an enhanced Th2 associated with eosinophilia. In addition, this study identified a pool of novel biomarkers for diagnosis of asthma and to label its subtypes. Trial registration http://www.chictr.org.cn (ChiCTR-OOC-15006221).

Interleukin-13-induced MUC5AC expression is regulated by a PI3K-NFAT3 pathway in mouse tracheal epithelial cells.

Interleukin-13 (IL-13) plays a critical role in asthma mucus overproduction, while the mechanisms underlying this process are not fully elucidated. Previous studies showed that nuclear factor of activated T cells (NFAT) is involved in the pathogenesis of asthma, but whether it can directly regulate IL-13-induced mucus (particularly MUC5AC) production is still not clear. Here we showed that IL-13 specifically induced NFAT3 activation through promoting its dephosphorylation in air-liquid interface (ALI) cultures of mouse tracheal epithelial cells (mTECs). Furthermore, both Cyclosporin A (CsA, a specific NFAT inhibitor) and LY294002 (a Phosphoinositide 3-kinase (PI3K) inhibitor) significantly blocked IL-13-induced MUC5AC mRNA and protein production through the inhibition of NFAT3 activity. We also confirmed that CsA could not influence the forkhead Box A2 (Foxa2) and mouse calcium dependent chloride channel 3 (mClca3) expression in IL-13-induced MUC5AC production, which both are known to be important in IL-13-stimulated mucus expression. Our study is the first to demonstrate that the PI3K-NFAT3 pathway is positively involved in IL-13-induced mucus production, and provided novel insights into the molecular mechanism of asthma mucus hypersecretion.

Computer-assisted discovery and evaluation of potential ribosomal protein S6 kinase beta 2 inhibitors.

S6K2 is an important protein in mTOR signaling pathway and cancer. To identify potential S6K2 inhibitors for mTOR pathway treatment, a virtual screening of 1,575,957 active molecules was performed using PLANET, AutoDock GPU, and AutoDock Vina, with their classification abilities compared. The MM/PB(GB)SA method was used to identify four compounds with the strongest binding energies. These compounds were further investigated using molecular dynamics (MD) simulations to understand the properties of the S6K2/ligand complex. Due to a lack of available 3D structures of S6K2, OmegaFold served as a reliable 3D predictive model with higher evaluation scores in SAVES v6.0 than AlphaFold, AlphaFold2, and RoseTTAFold2. The 150 ns MD simulation revealed that the S6K2 structure in aqueous solvation experienced compression during conformational relaxation and encountered potential energy traps of about 19.6 kJ mol-1. The virtual screening results indicated that Lys75 and Lys99 in S6K2 are key binding sites in the binding cavity. Additionally, MD simulations revealed that the ligands remained attached to the activation cavity of S6K2. Among the compounds, compound 1 induced restrictive dissociation of S6K2 in the presence of a flexible region, compound 8 achieved strong stability through hydrogen bonding with Lys99, compound 9 caused S6K2 tightening, and the binding of compound 16 was heavily influenced by hydrophobic interactions. This study suggests that these four potential inhibitors with different mechanisms of action could provide potential therapeutic options.

CCL11/CCR3-dependent eosinophilia alleviates malignant pleural effusions and improves prognosis.

Malignant pleural effusion (MPE) is a common occurrence in advanced cancer and is often linked with a poor prognosis. Eosinophils were reported to involve in the development of MPE. However, the role of eosinophils in MPE remains unclear. To investigate this, we conducted studies using both human samples and mouse models. Increased eosinophil counts were observed in patients with MPE, indicating that the higher the number of eosinophils is, the lower the LENT score is. In our animal models, eosinophils were found to migrate to pleural cavity actively upon exposure to tumor cells. Intriguingly, we discovered that a deficiency in eosinophils exacerbated MPE, possibly due to their anti-tumor effects generated by modifying the microenvironment of MPE. Furthermore, our experiments explored the role of the C-C motif chemokine ligand 11 (CCL11) and its receptor C-C motif chemokine receptor 3 (CCR3) in MPE pathology. As a conclusion, our study underscores the protective potential of eosinophils against the development of MPE, and that an increase in eosinophils through adoptive transfer of eosinophils or increasing their numbers improved MPE.

Angiotensin-converting enzyme I/D polymorphism is associated with COPD risk in Asian population: evidence from a meta-analysis.

Several molecular epidemiological studies were conducted in recent years to evaluate the risk of chronic obstructive pulmonary disease (COPD) associated with insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE). However, the results remain conflicting rather than conclusive. To derive a more precise estimation of association between ACE polymorphism and the risk of COPD, we performed a meta-analysis from all available relevant studies. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. There was a markedly positive association between the D allele or DD genotype and COPD risk in Asians (D vs. I: OR = 1.55, 95% CI = 1.407-2.44; DD vs. II: OR = 2.53, 95% CI = 1.65-3.89; DD vs. DI/II: OR = 2.09, 95% CI = 1.09-4.03), but this association was not observed in Europeans (D vs. I: OR = 0.93, 95% CI = 0.75-1.15; DD vs. II: OR = 0.86, 95% CI = 0.56-1.33; DD vs. DI/II: OR = 0.88, 95% CI = 0.63-1.23). Our meta-analysis provides strong evidence that D allele and DD homozygous might be significant genetic molecular markers for COPD susceptibility in Asians, but not for Europeans. Additional well-designed large studies were required for the validation of our results.

Airway epithelial cGAS inhibits LPS-induced acute lung injury through CREB signaling.

Increased levels of cytosolic DNA in lung tissues play an important role in acute lung injury. However, the detailed mechanisms involved remain elusive. Here, we found that cyclic GMP-AMP synthase (cGAS, a cytosolic DNA sensor) expression was increased in airway epithelium in response to increased cytosolic DNA. Conditional deletion of airway epithelial cGAS exacerbated acute lung injury in mice, cGAS knockdown augmented LPS-induced production of interleukin (IL)-6 and IL-8. Mechanically, deletion of cGAS augmented expression of phosphorylated CREB (cAMP response element-binding protein), and cGAS directly interacted with CREB via its C-terminal domain. Furthermore, CREB knockdown rescued the LPS-induced excessive inflammatory response caused by cGAS deletion. Our study demonstrates that airway epithelial cGAS plays a protective role in acute lung injury and confirms a non-canonical cGAS-CREB pathway that regulates the inflammatory responses in airway epithelium to mediate LPS-induced acute lung injury.

A rapid screening classifier for diagnosing COVID-19.

Rationale: Coronavirus disease 2019 (COVID-19) has caused a global pandemic. A classifier combining chest X-ray (CXR) with clinical features may serve as a rapid screening approach. Methods: The study included 512 patients with COVID-19 and 106 with influenza A/B pneumonia. A deep neural network (DNN) was applied, and deep features derived from CXR and clinical findings formed fused features for diagnosis prediction. Results: The clinical features of COVID-19 and influenza showed different patterns. Patients with COVID-19 experienced less fever, more diarrhea, and more salient hypercoagulability. Classifiers constructed using the clinical features or CXR had an area under the receiver operating curve (AUC) of 0.909 and 0.919, respectively. The diagnostic efficacy of the classifier combining the clinical features and CXR was dramatically improved and the AUC was 0.952 with 91.5% sensitivity and 81.2% specificity. Moreover, combined classifier was functional in both severe and non-serve COVID-19, with an AUC of 0.971 with 96.9% sensitivity in non-severe cases, which was on par with the computed tomography (CT)-based classifier, but had relatively inferior efficacy in severe cases compared to CT. In extension, we performed a reader study involving three experienced pulmonary physicians, artificial intelligence (AI) system demonstrated superiority in turn-around time and diagnostic accuracy compared with experienced pulmonary physicians. Conclusions: The classifier constructed using clinical and CXR features is efficient, economical, and radiation safe for distinguishing COVID-19 from influenza A/B pneumonia, serving as an ideal rapid screening tool during the COVID-19 pandemic.

Detection of Viruses by Multiplex Real-Time Polymerase Chain Reaction in Bronchoalveolar Lavage Fluid of Patients with Nonresponding Community-Acquired Pneumonia.

Background: Nonresponding pneumonia is responsible for the most mortality of community-acquired pneumonia (CAP). However, thus far, it is not clear whether viral infection plays an important role in the etiology of nonresponding CAP and whether there is a significant difference in the clinical characteristics between viral and nonviral nonresponding CAP. Methods: From 2016 to 2019, nonresponding CAP patients were retrospectively enrolled in our study. All patients received bronchoalveolar lavage (BAL) and virus detection in BAL fluid by multiplex real-time polymerase chain reaction (PCR), and clinical, laboratory, and radiographic data were collected. Results: A total of 43 patients were included. The median age was 62 years, and 65.1% of patients were male. Overall, 20 patients (46.5%) were identified with viral infection. Of these viruses, influenza virus (n = 8) and adenovirus (n = 7) were more frequently detected, and others included herpes simplex virus, human enterovirus, cytomegalovirus, human coronavirus 229E, rhinovirus, and parainfluenza virus. Compared with nonviral nonresponding CAP, only ground-glass opacity combined with consolidation was a more common imaging manifestation in viral nonresponding CAP. However, no obvious differences were found in clinical and laboratory findings between the presence and the absence of viral infections. Conclusions: Viral infections were particularly frequent in adults with nonresponding CAP. The ground-glass opacity combined with consolidation was a specific imaging manifestation for viral nonresponding CAP, while the clinical and laboratory data showed no obvious differences between viral and nonviral nonresponding CAP.

Response of patients with chest tightness variant asthma with routine asthma treatment regimen: A 1-year multicenter, prospective, real-world study.

BACKGROUND: Asthmatic patients with chest tightness as their only presenting symptom (chest tightness variant asthma [CTVA]) have clinical characteristics of eosinophilic airway inflammation similar to those of classic asthma (CA); however, whether CTVA has similar response to antiasthma treatment as compared with CA remains unclear. OBJECTIVE: The response of 76 CTVA patients to standard asthma treatments with inhaled corticosteroids with long-acting beta-agonists was explored in a 52-week multicenter, prospective, real-world study. RESULTS: After 52 weeks of treatment with therapy regimens used for CA, the mean 5-point Asthma Control Questionnaire (ACQ-5) score decreased markedly from 1.38(first administration) to 0.71 (52 weeks, mean decrease: 0.674, 95%CI: 0.447-0.900, P<.001).The mean asthma quality-of-life questionnaire (AQLQ) score increased from 5.77 (first administration) to 6.20 (52 weeks, mean increase: 0.441, 95% CI 0.258-0.625, P<.001). Furthermore, at week 52, FVC, FEV1 %, the diurnal variation in PEFand the PD20-FEV1 were significantly improved. Subgroup analysis revealed that the patients at first administration in the responsive group had higher ACQ-5 scores than those in the nonresponsive group (P < .05). CONCLUSION: In conclusion, patients with CTVA had a good therapeutic response to the guideline-recommended routine treatment (containing inhaled corticosteroids). The association between the treatment response and the severity of CTVA suggested that CTVA patients with higher ACQ-5 scores had better therapeutic effects.

Reactive oxygen species regulate Pseudomonas aeruginosa lipopolysaccharide-induced MUC5AC mucin expression via PKC-NADPH oxidase-ROS-TGF-alpha signaling pathways in human airway epithelial cells.

Mucin overproduction is a hallmark of chronic inflammatory airway diseases, such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis. Excessive production of mucin leads to airway mucus obstruction and contributes to morbidity and mortality in these diseases. The molecular mechanisms underlying mucin overproduction, however, still remain largely unknown. Here, we report that the bacterium P. aeruginosa, an important human respiratory pathogen causing cystic fibrosis, utilizes reactive oxygen species (ROS) to up-regulate MUC5AC mucin expression. Pseudomonas aeruginosa lipopolysaccharide (PA-LPS) induces production of ROS through protein kinase C (PKC)-NADPH oxidase signaling pathway in human epithelial cells. Subsequently, ROS generation by PA-LPS releases transforming growth factor-alpha (TGF-alpha), which in turn, leads to up-regulate MUC5AC expression. These findings may bring new insights into the molecular pathogenesis of P. aeruginosa infections and lead to novel therapeutic intervention for inhibiting mucin overproduction in patients with P. aeruginosa infections.

Synergistic induction of MUC5AC mucin by nontypeable Haemophilus influenzae and Streptococcus pneumoniae.

Mucin overproduction is a hallmark of chronic respiratory diseases (CRD) such as chronic obstructive pulmonary disease and asthma, and otitis media. Despite the fact that nontypeable Haemophilus influenzae (NTHi) and Streptococcus pneumoniae are co-existing under these disease conditions, little is known about how NTHi and S. pneumoniae induce mucin overproduction. Here we show that NTHi and S. pneumoniae, when present together, synergistically induce MUC5AC mucin transcription. TLR2/4-MyD88-TAK1 signaling cascade transmits signal to regulate the synergistic induction of MUC5AC. The activation of MKK3/6-p38 and ERK MAPK pathways are required for the synergistic induction of MUC5AC. Moreover, S. pneumoniae synergizes with NTHi to induce MUC5AC expression via AP-1-dependent mechanism. Thus, our studies provide direct evidence for the synergistic induction of MUC5AC in mixed infections and bring novel insights into our understanding of molecular mechanisms underlying polymicrobial infections in CRD and OM.

ATF3 is positively involved in particulate matter-induced airway inflammation in vitro and in vivo.

Airborne particulate matter (PM) has been reported to be associated with a wide range of respiratory disorders. However, the mechanisms underlying PM-induced airway inflammation remain largely unknown. Generally, ATF3 negatively regulates pro-inflammatory cytokines production in response to TLR4 signaling. Here we first showed ATF3 has promoting effects in PM-induced airway inflammation in vitro an in vivo. We demonstrated PM significantly upregulated ATF3 expression in HBE cells and in mouse lung tissues. ATF3 siRNA markedly inhibited, while ATF3-recombinant over-expression plasmid significantly increased PM-induced IL-6 expression in cultured HBE cells, and PM-induced IL-6, CXCL2 expression as well as neutrophil infiltration, mucus over-production in the lung of ATF3-/- mice were all notably reduced relative to the wild-type littermates. Furthermore, we showed ATF3 mediated PM-induced inflammatory cytokines expression partly through NF-κB and AP-1 pathways. Our data further elucidates the mechanisms underlying PM-induced airway inflammation, and indicates ATF3 may function as different role in response to different stimuli.

[Serum from partial hepatectomy rat and hepatocyte growth factor stimulate bone marrow cell expressing albumin and alpha fetoprotein].

OBJECTIVE: To explore the effect of serum from partial hepatectomy (PH) rat and hepatocyte growth factor (HGF) on expression of albumin and AFP of bone marrow cells. METHODS: The bone marrow mono-nucleated cells were separated from SD rats and cultured in three groups: (1) The medium only group as control was added normal fetal bovine serum; (2) Rat hepatic injury serum group (was added 15% rat serum from 2-AAF+PH model); (3) HGF group (HGF 20 ng/ml). The role of these factors was determined by RT-PCR, immunohistochemistry (IHC) and Western blot, using AFP and albumin as special hepatocytic markers. RESULTS: By immunohistochemical staining and Western blot, the fresh bone marrow cells were AFP-negative, same as the cells cultured with medium only group. While bone marrow cells, co-cultured with rat hepatic injury serum or HGF at day 10 and 20, expressed AFP protein. AFP mRNA expression could be found in bone marrow cells after 10 and 20 days cultured with rat hepatic injury serum or HGF, but not in fresh bone marrow cells and bone marrow cells cultured with medium only. Albumin mRNA expression was weak in fresh bone marrow cell and increased in groups 2 and 3. CONCLUSION: The rat hepatic injury serum or HGF could stimulate the expression of AFP protein and it's mRNA of bone marrow cells. Also they can stimulate albumin mRNA expression. It seems that, in bone marrow, there is a kind of cells so called bone marrow derived liver stem cell which can express albumin mRNA in a weak style.