Autocrine TGF-alpha is associated with Benzo(a)pyrene-induced mucus production and MUC5AC expression during allergic asthma.

OBJECTS: Benzo(a)pyrene (BaP), an environmental pollutant, is present in high concentrations in urban smog and cigarette smoke and has been reported to promote high mucin 5AC (MUC5AC) expression. Epithelium-derived inflammatory cytokines are considered an important modulator of mucus oversecretion and MUC5AC overexpression. Here, we investigated whether the effect of BaP on MUC5AC overexpression was associated with cytokine autocrine activity in vivo and in vitro. METHODS: In vivo, BALB/c mice were treated with ovalbumin (OVA) in the presence or absence of BaP. Allergy-induced mucus production was assessed by Alcian Blue Periodic acid Schiff (AB-PAS) staining. The human airway epithelial cell line NCI-H292 was used in vitro. MUC5AC and transforming growth factor (TGF)-α mRNA levels were assessed with real-time quantitative PCR. The concentration of cytokines was measured by ELISA. The MUC5AC, p-ERK, ERK, p-EGFR and EGFR proteins were detected by Western blotting in cells or by immunohistochemistry in mouse lungs. Small-interfering RNAs were used for gene silencing. RESULTS: TGF-α was overproduced in the supernatant of NCI-H292 cells treated with BaP. Knockdown of TGF-α expression inhibited the BaP-induced increase in MUC5AC expression and subsequent activation of the EGFR-ERK signalling pathway. Knocking down aryl hydrocarbon receptor (AhR) expression or treatment with an ROS inhibitor (N-acetyl-L-cysteine) could relieve the TGF-α secretion induced by BaP in epithelial cells. In an animal study, coexposure to BaP with OVA increased mucus production, MUC5AC expression and ROS-EGFR-ERK activation in the lung as well as TGF-α levels in bronchoalveolar lavage fluid (BALF). Furthermore, the concentration of TGF-α in BALF was correlated with MUC5AC mRNA levels. Additionally, TGF-α expression was found to be positively correlated with MUC5AC expression in the airway epithelial cells of smokers. Compared with non-smoker asthma patients, TGF-α serum levels were also elevated in smoker asthma patients. CONCLUSION: Autocrine TGF-α was associated with BaP-induced MUC5AC expression in vitro and in vivo. BaP induced TGF-α secretion by activating AhR and producing ROS, which led to activation of the EGFR-ERK pathway.

Growth differentiation factor 11 induces skeletal muscle atrophy via a STAT3-dependent mechanism in pulmonary arterial hypertension.

Skeletal muscle wasting is a clinically remarkable phenotypic feature of pulmonary arterial hypertension (PAH) that increases the risk of mortality. Growth differentiation factor 11 (GDF11), centrally involved in PAH pathogenesis, has an inhibitory effect on skeletal muscle growth in other conditions. However, whether GDF11 is involved in the pathogenesis of skeletal muscle wasting in PAH remains unknown. We showed that serum GDF11 levels in patients were increased following PAH. Skeletal muscle wasting in the MCT-treated PAH model is accompanied by an increase in circulating GDF11 levels and local catabolic markers (Fbx32, Trim63, Foxo1, and protease activity). In vitro GDF11 activated phosphorylation of STAT3. Antagonizing STAT3, with Stattic, in vitro and in vivo, could partially reverse proteolytic pathways including STAT3/socs3 and iNOS/NO in GDF11-meditated muscle wasting. Our findings demonstrate that GDF11 contributes to muscle wasting and the inhibition of its downstream molecule STAT3 shows promise as a therapeutic intervention by which muscle atrophy may be directly prevented in PAH.

Protective effects of progesterone on pulmonary artery smooth muscle cells stimulated with Interleukin 6 via blocking the shuttling and transcriptional function of STAT3.

BACKGROUND: Sex hormone paradox is a crucial but unresolved issue in the field of pulmonary artery hypertension (PAH), and is thought to be related to different pathogenic factors. Inflammation is one of pathological mechanisms of PAH development. However, effects of sex hormones on the pulmonary vasculature under the condition of inflammation are still elusive. METHODS: Interleukin-6 (IL-6) was used as a representative inflammatory stimulator. Effects of 17ß-estradiol or progesterone on human pulmonary artery smooth muscle cells (PASMCs) were measured under the condition of IL-6. Cell functions of proliferation and migration were measured by Alarmar Blue, EdU assay, wound-healing assay and transwell chambers. We explored further mechanisms using western blot, immunofluorescence, co-immunoprecipitation, qPCR and chromatin immunoprecipitation. RESULTS: Our results revealed that IL-6 promoted the proliferation of PASMCs, but progesterone could reverse the adverse effect of IL-6. The protective effect was dependent on progesterone receptor (PGR). By interacting with signal transducer and activator of transcription 3 (STAT3), activated PGR could reduce the IL-6-induced nuclear translocation of STAT3 and prevent STAT3-chromatin binding in PASMCs, leading to the decreased transcription of downstream CCND1 and BCL2. Alternatively, progesterone slightly decreased the phosphorylation of pro-proliferative Erk1/2 and Akt kinases and upregulated the anti-proliferative pSmad1-Id1/2 axis in IL-6-incubated PASMCs. CONCLUSIONS: Progesterone played a protective role on PASMCs in the context of IL-6, by blocking the functions of STAT3. Our findings might assist in explaining the clinical phenomenon of better prognosis for women with PAH.

Serum cartilage oligomeric matrix protein is decreased in patients with pulmonary hypertension: a potential protective factor.

Cartilage oligomeric matrix protein (COMP) was a protective factor in the cardiovascular system. Previous studies showed that hypoxia led to decreased COMP in rat models of pulmonary hypertension. However, the expression pattern of COMP in the pulmonary hypertension population was unclear. A total of 35 patients newly diagnosed with pulmonary hypertension and 70 controls were enrolled in the study. Circulating COMP concentrations of serum samples were measured by enzyme-linked immunosorbent assay and were analyzed the association with multiple clinical variables. Serum COMP concentrations in the pulmonary hypertension group were significantly declined in comparison with age- and sex-matched normal controls, especially in the female subgroup. No significant difference of COMP concentrations was observed in the etiological classification, heart function classification, and risk stratification. Major hemodynamic parameters, six-minute walk distance, N-terminal pro brain natriuretic peptide, and short-term prognosis were not statistically associated with COMP. However, some echocardiography parameters, like tricuspid annular plane systolic excursion and mean right atrial pressure, were found the negative relation to COMP concentrations. In conclusion, serum COMP levels were decreased in the patients with pulmonary hypertension, which was in accordance with its known biological effects. Its association with long-term prognosis was worth further exploring.

Respiratory physicians' awareness and referral of pulmonary rehabilitation in China: a cross-sectional study.

BACKGROUND: Pulmonary rehabilitation (PR) has demonstrated physiological, symptom reducing, psychosocial, and health care savings benefits in multiple outcome areas for patients with chronic respiratory diseases. Physicians' PR awareness and PR referral practices are key in PR promotion. However, PR awareness and referral among respiratory physicians in China have rarely been studied. This study aims to explore respiratory physicians' perceptions towards PR and assess the referral of PR in China. METHODS: A self-administered questionnaire was distributed via WeChat and emails to respiratory physicians in hospitals to assess their attitudes toward and knowledge of PR and identify treatment barriers. The study was conducted from June through October 2019. RESULTS: As reported in the 520 questionnaires collected through October 2019 most respondents had heard about PR, and many had knowledge of PR practice, but relatively few had referred patients to PR before having responded to the survey. Education, region of practice, and duration of practice are significant factors that influenced the participating respiratory physicians' awareness of PR. The percentage of referral was influenced by physicians' education, region, and duration of practice. The absence of PR facilities was the main barrier to respiratory physicians' referral of patients to PR. CONCLUSIONS: Chinese respiratory physicians' awareness of PR and referral to PR remain insufficient to support the delivery of PR to patients with chronic respiratory diseases. PR training for respiratory physicians and building PR centers are necessary to remedy these conditions.

Predictors of mortality for hospitalized young adults aged less than 60 years old with severe COVID-19: a retrospective study.

BACKGROUND: To analyze the clinical characteristics and predictors for mortality of adult younger than 60 years old with severe coronavirus disease 2019 (COVID-19). METHODS: We retrospectively retrieved data for 152 severe inpatients with COVID-19 including 60 young patients in the Eastern Campus of Wuhan University affiliated Renmin Hospital in Wuhan, China, from January 31, 2020 to February 20, 2020. We recorded and analyzed patients' demographic, clinical, laboratory, and chest CT findings, treatment and outcomes data. RESULTS: Of those 60 severe young patients, 15 (25%) were died. Male was more predominant in deceased young patients (12, 80%) than that in recovered young patients (22, 49%). Hypertension was more common among deceased young patients (8, 53%) than that in recovered young patients (7, 16%). Compared with the recovered young patients, more deceased young patients presented with sputum (11, 73%), dyspnea (12, 80%) and fatigue (13, 87%). Only sputum, PSI and neutrophil counts were remained as independent predictors of death in a multivariate logistic regression model. Among ARDS patients, the recovered were administrated with corticosteroid earlier and anticoagulation. The addition of neutrophil counts >6.3×109/L to the SMART-COP score resulted in improved area under the curves. CONCLUSIONS: Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) infection in young deceased patients appears to cause exuberant inflammatory responses, leading to compromised oxygen exchange, coagulation and multi-organ dysfunction. In addition, young patients with ARDS could benefit from adjuvant early corticosteroid and anticoagulation therapy. The expanded SMART-COP could predict the fatal outcomes with optimal efficiency.

Essential Genes and MiRNA-mRNA Network Contributing to the Pathogenesis of Idiopathic Pulmonary Arterial Hypertension.

Background: Idiopathic pulmonary arterial hypertension (IPAH) is a life-threatening disease. Owing to its high fatality rate and narrow therapeutic options, identification of the pathogenic mechanisms of IPAH is becoming increasingly important. Methods: In our research, we utilized the robust rank aggregation (RRA) method to integrate four eligible pulmonary arterial hypertension (PAH) microarray datasets and identified the significant differentially expressed genes (DEGs) between IPAH and normal samples. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were performed to analyze their functions. The interaction network of protein-protein interaction (PPI) was constructed to explore the correlation between these DEGs. The functional modules and hub genes were further identified by the weighted gene coexpression network analysis (WGCNA). Moreover, a miRNA microarray dataset was involved and analyzed to filter differentially expressed miRNAs (DE-miRNAs). Potential target genes of screened DE-miRNAs were predicted and merged with DEGs to explore a miRNA-mRNA network in IPAH. Some hub genes were selected and validated by RT-PCR in lung tissues from the PAH animal model. Results: A total of 260 DEGs, consisting of 183 upregulated and 77 downregulated significant DEGs, were identified, and some of those genes were novel. Their molecular roles in the etiology of IPAH remained vague. The most crucial functional module involved in IPAH is mainly enriched in biological processes, including leukocyte migration, cell chemotaxis, and myeloid leukocyte migration. Construction and analysis of the PPI network showed that CXCL10, CXCL9, CCR1, CX3CR1, CX3CL1, CXCR2, CXCR1, PF4, CCL4L1, and ADORA3 were recognized as top 10 hub genes with high connectivity degrees. WGCNA further identified five main functional modules involved in the pathogenesis of IPAH. Twelve upregulated DE-miRNAs and nine downregulated DE-miRNAs were identified. Among them, four downregulated DEGs and eight upregulated DEGs were supposed to be negatively regulated by three upregulated DE-miRNAs and three downregulated DE-miRNAs, respectively. Conclusions: This study identifies some key and functional coexpression modules involved in IPAH, as well as a potential IPAH-related miRNA-mRNA regulated network. It provides deepening insights into the molecular mechanisms and provides vital clues in seeking novel therapeutic targets for IPAH.

LncRNA NEAT1 contributes to the acquisition of a tumor like-phenotype induced by PM 2.5 in lung bronchial epithelial cells via HIF-1α activation.

The hazards of particulate matter (PM2.5) on human respiratory health have been previously reported. However, the molecular mechanisms underlying PM2.5-induced lung carcinogenesis have rarely been studied. In the present study, we explored the effects of PM2.5 on the epithelial-mesenchymal transition (EMT) and acquisition of cancer stem cell (CSC)-like properties in lung bronchial epithelial cells. We found that exposure of PM2.5 enhanced lung bronchial epithelial cell proliferation and EMT. In addition, the expression level of CSC-like biomarkers, CD133 and CD44, was significantly elevated by PM2.5 in vitro. Nuclear paraspeckle assembly transcript 1 (NEAT1) has been reported to participate in lung cancer. Loss of NEAT1 represses the malignant transformation of BEAS-2B and HBE cells induced by PM2.5. NEAT1 interacts with microRNA (miR)-582-5p, and miR-582-5p reverses the pro-tumor effects of NEAT1 overexpression. Hypoxia-inducible factor (HIF)-1α is an important transcription factor in the pathological responses to hypoxia. HIF-1α was a predicted target for miR-582-5p, and a direct correlation between them was identified. Inhibitors of miR-582-5p rescued HIF-1α expression, which was attenuated by a lack of NEAT1. In conclusion, PM2.5 increased NEAT1 expression, which, by binding with miR-582-5p, released HIF-1α and promoted EMT and the acquisition of CSC-like characteristics.

Left atrial dysfunction in patients with obstructive sleep apnea: a combined assessment by speckle tracking and real-time three-dimensional echocardiography.

BACKGROUND: At present, little research concerning the assessment of left atrial (LA) dysfunction in patients with obstructive sleep apnea (OSA) using a combined assessment by speckle tracking (STE) and real-time three-dimensional echocardiography (RT3DE) is available. The objective of this study was to evaluate the LA volume and function by STE and RT3DE in patients with OSA. METHODS: In our cohort study, ninety-two OSA patients and 50 healthy individuals were enrolled. According to the apnea hypopnea index (AHI), patients (AHI >15/h) classified as having moderate and severe OSA were included. The patients were divided into 2 subgroups according to the left ventricular mass index (LVMI): the left ventricular hypertrophy (LVH) group in which patients had LVH (n=30), and the nonLVH group in which patients did not have LVH (n=62). All subjects underwent LA function assessment by conventional techniques and the combination of STE and RT3DE. RESULTS: OSA patients showed impaired LA global longitudinal strain during early diastole (LA S-E) and systole (LA S-S) but increased LA global longitudinal strain during late diastole (LA S-A) compared with controls (all P<0.05). In addition, OSA patients with LVH had lower LA S-S and LA S-E than patients without LVH (all P<0.05). With regard to parameters obtained from RT3DE, indexed LA maximum, minimum, and preatrial contraction volumes (LAVi-max, LAVi-min, LAVi-preA) and the LA active emptying fraction (LAAEF) were significantly higher, whereas the LA passive emptying fraction (LVPEF) was significantly lower in OSA patients in comparison with controls (all P<0.05). The LA total emptying fraction (LVTEF) and the LA expansion index were significantly lower in OSA patients with LVH than in controls (all P<0.05). Additionally, OSA patients with LVH had higher LAVi-min, LAVi-preA and LAAEVi but lower LAPEF than patients without LVH (all P<0.05). CONCLUSIONS: OSA is associated with LA remodeling and dysfunction that occurs in the subclinical stage before the development of LVH and left ventricular diastolic dysfunction, and it will be further aggravated along with the development of LVH and OSA severity. The process can be detected with a detailed evaluation of active and passive functions of the LA using the STE and RT3DE method.