Dandan Zong

C-Kit/c-Kit ligand interaction of bone marrow endothelial progenitor cells is influenced in a cigarette smoke extract-induced emphysema model

ABSTRACT Background: Smoking causes lung endothelial cell apoptosis and emphysema. Derived from bone marrow, circulating endothelial progenitor cells (EPCs) maintain vascular integrity by replacing and repairing damaged endothelial cells. Smoking influences the number of circulating EPCs. Recruitment of EPCs from bone marrow to peripheral blood depends on the interaction of c-Kit/soluble c-Kit ligand (sKitL). We hypothesized that smoking might influence c-Kit(+) EPCs/sKitL interaction in bone marrow in the development of smoking-related emphysema. In this study, we used a cigarette smoke extract (CSE)-induced emphysema model. Methods: Mice were injected intraperitoneally with PBS/CSE and sacrificed at day 28. Lung function and pathology of lung tissue were measured to characterize the model. Expressions of c-Kit in the lung tissue were assayed. Bone marrow cells were isolated by red blood cell lysis. EPCs/c-Kit(+) EPCs in nonred blood cells were analyzed by flow cytometry. Expressions of KitL and MMP-9, and activity MMP-9 in bone marrow were measured. Results: Our data demonstrated that gene and protein expressions of c-Kit were decreased in the lung tissue in this model. Compared with the control group, the number of bone marrow nonred blood cells was unchanged following CSE treatment, while the depletion of bone marrow EPCs/c-Kit(+) EPCs was significant. The level of sKitL was reduced in the bone marrow in the model. The reduction of sKitL was associated with deregulated KitL expression and decreased MMP-9 activity. Conclusions: The interaction between c-Kit and sKitL in bone marrow EPCs, a critical step in endothelial repair, is negatively affected in a CSE-induced emphysema model.

Notch signaling in lung diseases: focus on Notch1 and Notch3.

Notch signaling is an evolutionarily conserved cell–cell communication mechanism that plays a key role in lung homeostasis, injury and repair. The loss of regulation of Notch signaling, especially Notch1 and Notch3, has recently been linked to the pathogenesis of important lung diseases, in particular, chronic obstructive pulmonary disease (COPD), asthma, pulmonary fibrosis, pulmonary arterial hypertension (PAH), lung cancer and lung lesions in some congenital diseases. This review focuses on recent advances related to the mechanisms and the consequences of aberrant or absent Notch1/3 activity in the initiation and progression of lung diseases. Our increasing understanding of this signaling pathway offers great hope that manipulating Notch signaling may represent a promising alternative complementary therapeutic strategy in the future.

Relation between serum leptin levels, lipid profiles and neurocognitive deficits in Chinese OSAHS patients

ABSTRACT Objective: The aim of this study was to compare serum leptin, apolipoprotein A1 (ApoA1), apolipoprotein J (ApoJ) and apolipoprotein H (ApoH) levels in males with obstructive sleep apnea and hypopnea syndrome (OSAHS) to those in healthy control subjects and to examine the possible relation between neurocognitive performance and these factors/serum markers in the subjects. Methods: In this observational, cross-sectional study, a full-night polysomnography and sensitive neuropsychological assessment were performed on 50 newly diagnosed Chinese male patients and 30 healthy subjects. Fasting blood samples were used to measure leptin and ApoA1, ApoH and ApoJ levels using ELISA. Results: Compared with normal control subjects, OSAHS patients have significantly lower levels of ApoA1 and higher levels of leptin, ApoH and ApoJ. After adjustment for age, years of education, body mass index (BMI) and apnea–hypopnea index, leptin and ApoA1 were associated with global cognitive function, and leptin level was positively correlated with inhibition reaction time. ApoJ was negatively correlated with visual reproduction and logical memory performance. Multiple regression analysis shows that from age, BMI, education year, biomarker levels and the parameters of PSG, only the variables of leptin and education year added to the prediction of the Montreal cognitive assessment score in a statistically significant way. Conclusions: Abnormal expression of leptin and apolipoproteins and poor performance on neuropsychological tests were observed in patients with OSAHS. There is also an association between serum leptin, ApoA1, and ApoJ levels and cognitive performance in the patients.

miR-34a is involved in CSE-induced apoptosis of human pulmonary microvascular endothelial cells by targeting Notch-1 receptor protein

BackgroundAbnormal apoptosis of lung endothelial cells has been observed in emphysematous lung tissue and has been suggested to be an important upstream event in the pathogenesis of chronic obstructive pulmonary disease (COPD). Studies have shown that microRNAs (miRNAs) contribute to the pathogenesis of pulmonary diseases by regulating cell apoptosis. The present study was designed to investigate the expression of microRNA-34a (miR-34a) in human pulmonary microvascular endothelial cells (HPMECs) exposed to cigarette smoke extract (CSE), and the potential regulatory role of miR-34a in endothelial cell apoptosis.ResultsOur results showed that the expression of miR-34a was significantly increased in CSE-treated HPMECs, and inhibiting miR-34a attenuated CSE-induced HPMEC apoptosis. Furthermore, expression of Notch-1, a receptor protein in the Notch signalling pathway, was decreased and was inversely correlated with miR-34a expression in HPMECs treated with CSE. Computational miRNA target prediction confirmed that Notch-1 is a target of miR-34a. Luciferase reporter assay further confirmed the direct interaction between miR-34a and the 3’-untranslated region (UTR) of Notch-1. Restoration of Notch-1 pathway was able to partially block the effect of miR-34a on HPMEC apoptosis. These results indicate that Notch-1 is a critical downstream target of miR-34a in regulating the CSE-induced HPMEC apoptosis.ConclusionsOur results suggest that miR-34a plays a key role in CSE-induced endothelial cell apoptosis by directly regulating its target gene Notch-1 in endothelial cells.

Notch1 regulates endothelial apoptosis via ERK pathway in chronic obstructive pulmonary disease

The Notch signaling pathway plays critical role for determining cell fate by controlling proliferation, differentiation, and apoptosis. In the current study, we investigated the roles of the Notch signaling pathway in cigarette smoke (CS)-induced endothelial apoptosis in chronic obstructive pulmonary disease (COPD). We obtained surgical specimens from 10 patients with COPD and 10 control participants. Notch1, 2, and 4 express in endothelial cells, whereas Notch3 mainly localizes in smooth muscle cells. Compared with control groups, we found that the expression of Notch1, 3, and 4 decreased, as well as their target genes Hes1 and Hes2, while the expression of Notch2 and extracellular signal-regulated kinase (ERK)1/2 increased in COPD patients compared with controls, as well as in human pulmonary microvascular endothelial cells (HPMECs) when exposed to CS extract (CSE). Overexpression of Notch1 with N1ICD in HPMECs markedly alleviated the cell apoptosis induced by CSE. The ERK signaling pathway was significantly activated by CSE, which correlated with CSE-induced apoptosis. However, this activation can be abolished by N1ICD overexpression. Furthermore, treatment of PD98059 (ERK inhibitor) significantly alleviated CSE-induced apoptosis, as well as reduced the methylation of mitochondrial transcription factor A (mtTFA) promoter, which was correlated with CS-induced endothelial apoptosis. These results suggest that CS alters Notch signaling in pulmonary endothelial cells. Notch1 protects against CS-induced endothelial apoptosis in COPD through inhibiting the ERK pathway, while the ERK pathway further regulates the methylation of mtTFA promotor.

The protective effect of PRMT6 overexpression on cigarette smoke extract-induced murine emphysema model

Background Cigarette smoke exposure is the most common risk factor for emphysema, which is one of the major pathologies of COPD. Protein arginine methyltransferase 6 (PRMT6) is a nuclear enzyme that specially catalyzes dimethylation of R2 in histone H3 (H3R2me2a). H3R2me2a prevents trimethylation of H3K4 (H3K4me3), which is located in the transcription start sites of genes in mammalian genomes. We attempted to determine the expression of PRMT6 in human samples, and investigate whether the upregulation of PRMT6 expression can attenuate the development of cigarette smoke extract (CSE)-induced emphysema. Further experiments were performed to elucidate the molecular mechanisms involved. Materials and methods Human lung tissues were obtained from patients undergoing pneumonectomy for benign pulmonary lesions. BALB/c mice were treated with lentiviral vectors intratracheally and injected with CSE three times. The protein expression of PRMT6, H3R2me2a, and H3K4me3 in human and mouse samples, as well as B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), and endothelial nitric oxide synthase (eNOS) in mice were detected in lung homogenates by Western blotting. The mRNA expression of cyclooxygenase-2, interleukin-6, Bcl-2, Bax, and eNOS in mice was measured by quantitative real-time polymerase chain reaction. Results The expression of PRMT6 was significantly downregulated in the pulmonary parenchyma in smokers with COPD as well as in mice treated with CSE. Overexpression of PRMT6 was detected in the CSE + Lenti-PRMT6 group of mice, which reversed the expression of H3R2me2a and H3K4me3. Inflammation, apoptosis, and oxidative stress levels were severe in the CSE-treated emphysema mice compared with the control group, which was inhibited by the overexpression of PRMT6. Conclusion The overexpression of PRMT6 might inhibit inflammation, apoptosis, and oxidative stress in CSE-induced emphysema mediated by H3R2me2a.

Pulmonary Diseases and Epigenetics

Abstract Pulmonary diseases are one of the leading causes of death in the world. Chronic obstructive pulmonary disease (COPD), asthma, interstitial lung diseases, pulmonary arterial hypertension (PAH), lung tuberculosis, and pulmonary embolism, as well as other disorders, are significant public health burdens. Although advances in methods of detection, intervention, and treatment have prolonged life for patients, these complex illnesses continue to have serious effects on a large segment of the global population. Epigenetics is defined as the study of heritable changes in gene expression or cellular phenotype caused by mechanisms that do not alter the nucleotide sequence. There are three main classes of epigenetic marks: DNA methylation, histone modifications, and noncoding RNAs. DNA methylation involves the addition of a methyl group to the 5 position of cytosine by DNA methyltransferases and can be inherited through cell division. Histone modifications are posttranslational processes such as acetylation, methylation, phosphorylation, and ubiquitination of the tails of core histones, each of which plays different roles in gene expression. MicroRNAs are approximately 22 nucleotide-long regulatory RNAs that control gene expression by binding to messenger RNA (mRNA), leading to mRNA degradation or inhibition of protein translation. Increasingly, the evidence suggests that these three important epigenetic mechanisms play significant roles in the pathogenetic processes of lung diseases. Understanding these mechanisms may lead to the development of novel diagnostic and therapeutic approaches. In this chapter the influence of epigenetic variations on the pathophysiology of COPD, asthma, interstitial lung diseases, PAH, lung tuberculosis, and pulmonary embolism is described.

Diagnosis and treatment for 2 cases of tuberous sclerosis complex with pulmonary lymphangioleiomyomatosis

To improve the diagnosis and treatment for tuberous sclerosis complex (TSC) with pulmonary lymphangioleiomyomatosis, a retrospective analysis was performed based on the clinical data of 2 patients with such disease. Both of them have typical thin-walled cystic lesion throughout the lung field, renal angioleiomyolipoma, and various degrees of skin lesions. Central nervous system is involved in one patient. Lesions in the lung and kidney in one patient were improved significantly after 5 months of rapamycin treatment. The clinical phenotypes were diverse in TSC patients. The CT imaging showed typical characteristics when the lung was invaded by the tumor. When a patient was diagnosed as pulmonary lymphangioleiomyomatosis, we should pay attention to the clinical screening of TSC. Rapamycin is an effective and safe treatment for this disease.