Cui Zhai

Inhibition of Notch3 prevents monocrotaline-induced pulmonary arterial hypertension

ABSTRACT It has been shown that activation of Notch3 signaling is involved in the development of pulmonary arterial hypertension (PAH) by stimulating pulmonary arteries remodeling, while the molecular mechanisms underlying this are still largely unknown. The aims of this study are to address these issues. Monocrotaline dramatically increased right ventricle systolic pressure to 39.0 ± 2.6 mmHg and right ventricle hypertrophy index to 53.4 ± 5.3% (P < 0.05 versus control) in rats, these were accompanied with significantly increased proliferation and reduced apoptosis of pulmonary vascular cells as well as pulmonary arteries remodeling. Treatment of PAH model with specific Notch inhibitor DAPT significantly reduced right ventricle systolic pressure to 26.6 ± 1.3 mmHg and right ventricle hypertrophy index to 33.5 ± 2.6% (P < 0.05 versus PAH), suppressed proliferation and enhanced apoptosis of pulmonary vascular cells as well as inhibited pulmonary arteries remodeling. Our results further indicated that level of Notch3 protein and NICD3 were increased in MCT-induced model of PAH, this was accompanied with elevation of Skp2 and Hes1 protein level and reduction of P27Kip1. Administration of rats with DAPT-prevented MCT induced these changes. Our results suggest that Notch3 signaling activation stimulated pulmonary vascular cells proliferation by Skp2-and Hes1-mediated P27Kip1 reduction, and Notch3 might be a new target to treat PAH.

Association of Serum Galectin-3 with the Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Background Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) aggravates the overall severity in COPD patients, resulting in severe morbidity and mortality. However, there are no objective biomarkers currently available to predict the development of AECOPD. Several studies have indicated that galectin-3 (Gal-3) is involved in diseases characterized by excessive inflammatory response and fibrosis. The objective of this study was to examine the dynamic changes of Gal-3 in acute exacerbation and convalescence phases of COPD. Material/Methods Serum levels of Gal-3, high sensitivity C-reactive protein (hsCRP), and prohormone of brain natriuretic peptide (pro-BNP) were determined using multiplex enzyme-linked immunosorbent assay kits. Serum levels of Gal-3 in 44 patients with COPD were further analyzed and correlated with the parameters of lung function and the biomarkers of systemic inflammation. Results The mean level of serum Gal-3 was significantly higher in acute exacerbation of COPD compared with the level in COPD convalescence phase (32.10±9.83 versus 29.02±8.68 ng/mL, p<0.01). Serum levels of Gal-3 positively correlated with hsCRP (r=0.354, p=0.018 for total patients) and pro-BNP (r=0.319, p=0.035 for total patients) in AECOPD. In addition, the level of Gal-3 was the highest in the current smoker group, and the lowest in the never-smoker group in either the acute exacerbation phase (33.91±3.55 versus 29.12±11.73 ng/mL, p=0.036) or the convalescence phase (30.94±3.40 versus 27.76±9.68 ng/mL, p=0.045) of COPD. Conclusions Our results indicated that serum Gal-3 is increased in AECOPD patients, which is also positively associated with systemic inflammation and smoking in patients with COPD, suggesting that Gal-3 might be a valuable biomarker for AECOPD.

Activation of PPARγ inhibits HDAC1-mediated pulmonary arterial smooth muscle cell proliferation and its potential mechanisms

ABSTRACT The downstream targets of histone deacetylase 1 (HDAC1) mediation of platelet‐derived growth factor (PDGF)‐induced pulmonary arterial smooth muscle cell (PASMC) proliferation are still unclear, and it is also unknown whether activation of peroxisome proliferator‐activated receptor &ggr; (PPAR&ggr;) modulates HDAC1 and its down‐stream targets in PASMCs. The present study aims to address these issues. Our results showed that PDGF dose‐ and time‐dependently induced PASMC proliferation, and this was accompanied by an increase of HDAC1 and cyclin‐dependent kinase 4 (CDK4) protein expression as well as a reduction of microRNA‐124 (miR‐124). Pre‐silencing of HDAC1 with small interfering RNA (siRNA) abolished PDGF‐induced miR‐124 down‐regulation, CDK4 protein up‐regulation, and PASMC proliferation. In addition, over‐expression of miR‐124 reversed CDK4 protein elevation and PASMC proliferation caused by PDGF. We further found that pre‐incubation of PASMCs with pioglitazone, an agonist of PPAR&ggr; receptors, significantly increased PPAR&ggr; expression and activity, and blocked PDGF‐stimulated cell proliferation by regulating HDAC1‐mediated miR‐124 and CDK4 expression. Our study indicates that HDAC1/miR‐124/CDK4 axis plays an important role in PDGF‐induced PASMC proliferation, and activation of PPAR&ggr; inhibits PASMC proliferation by acting on HDAC1 pathway.

Resveratrol inhibits monocrotaline-induced pulmonary arterial remodeling by suppression of SphK1-mediated NF-κB activation

Aims: This study aims to explore the molecular mechanisms underlying sphingosine kinase 1 (SphK1) inducing pulmonary vascular remodeling and resveratrol suppressing pulmonary arterial hypertension (PAH). Material and methods: monocrotaline (MCT) was used to induce PAH in rats. The right ventricular systolic pressure (RVSP), right ventricle hypertrophy index (RVHI) and histological analyses including hematoxylin and eosin staining, the percentage of medial wall thickness (%MT), &agr;‐SMA staining and Ki67 staining were performed to evaluate the development of PAH. Protein levels of SphK1, nuclear factor‐kappaB (NF‐&kgr;B)‐p65 and cyclin D1 were determined using immunoblotting. Sphingosine‐1‐phosphate (S1P) concentration was measured using enzyme‐linked immunosorbent assay. Key findings: SphK1 protein level, S1P production, NF‐&kgr;B activation and cyclin D1 expression were significantly increased in MCT‐induced PAH rats. Inhibition of SphK1 by PF543 suppressed S1P synthesis and NF‐&kgr;B activation and down‐regulated cyclin D1 expression in PAH rats. Suppression of NF‐&kgr;B by pyrrolidine dithiocarbamate (PDTC) also reduced cyclin D1 expression in PAH model. Treatment of PAH rats with either PF543 or PDTC dramatically decreased RVSP, RVHI and %MT and reduced pulmonary arterial smooth muscle cells proliferation and pulmonary vessel muscularization. In addition, resveratrol effectively inhibited the development of PAH by suppression of SphK1/S1P‐mediated NF‐&kgr;B activation and subsequent cyclin D1 expression. Significance: SphK1/S1P signaling induces the development of PAH by activation of NF‐&kgr;B and subsequent up‐regulation of cyclin D1 expression. Resveratrol inhibits the MCT‐induced PAH by targeting on SphK1 and reverses the downstream changes of SphK1, indicating that resveratrol might be a therapeutic agent for the prevention of PAH.

Activation of AMPK prevents monocrotaline-induced pulmonary arterial hypertension by suppression of NF-κB-mediated autophagy activation

Aims: It has been shown that activation of autophagy is involved in the development of pulmonary arterial hypertension (PAH). Meanwhile, activation of nuclear factor‐kappaB (NF‐&kgr;B) has been found to induce autophagy in several types of human diseases including cancer and cardiac diseases. However, it is still unknown whether NF‐&kgr;B mediates autophagy activation in PAH, and whether activation of adenosine monophosphate‐activated protein kinase (AMPK) benefits PAH by modulation of NF‐&kgr;B and autophagy. Main methods: Rat models of PAH were established by intraperitoneally injection of monocrotaline (MCT). The right ventricle systolic pressure (RVSP), right ventricular hypertrophy index (RVHI), and percentage of medial wall thickness (%MT) were performed to evaluate the development of PAH. The translocation of NF‐&kgr;B p65 from cytosol to nucleus, the protein levels of LC3A, LC3B, and RND3 were determined by immunoblotting. Metformin was used to activate AMPK. Key findings: NF‐&kgr;B and autophagy were significantly activated in MCT‐induced PAH rats, this was accompanied with the reduction of RND3. Pharmacological inhibition of NF‐&kgr;B suppressed MCT‐induced activation of autophagy and down‐regulation of RND3 expression and reduced RVSP, RVHI, and %MT in MCT‐induced PAH rats. In addition, activation of AMPK by metformin suppressed NF‐&kgr;B‐mediated autophagy activation and down‐regulation of RND3 and therefore reduced RVSP, RVHI, and %MT in MCT‐induced PAH. Significance: NF‐&kgr;B‐induced autophagy activation and consequent down‐regulation of RND3 contributes to the development of PAH in MCT‐treated rats. Activation of AMPK prevents the development of PAH by targeting on NF‐&kgr;B to suppress autophagy and vascular remodeling.

Activation of peroxisome proliferation-activated receptor-γ inhibits transforming growth factor-β1-induced airway smooth muscle cell proliferation by suppressing Smad-miR-21 signaling: LIU et al.

The aims of the current study were to examine the signaling mechanisms for transforming growth factor‐β1 (TGF‐β1)‐induced rat airway smooth muscle cell (ASMC) proliferation and to determine the effect of activation of peroxisome proliferation–activated receptor‐γ (PPAR‐γ) on TGF‐β1‐induced rat ASMC proliferation and its underlying mechanisms. TGF‐β1 upregulated microRNA 21 (miR‐21) expression by activating Smad2/3, and this in turn downregulated forkhead box O1 (FOXO1) mRNA expression. In addition, TGF‐β1–Smad–miR‐21 signaling also downregulated phosphatase and tensin homolog deleted on chromosome ten (PTEN) expression and thus de‐repressed the PI3K–Akt pathway. Depletion of PTEN reduced the nuclear FOXO1 protein level without affecting its mRNA level. Inhibition of the PI3K–Akt pathway or proteasome function reversed PTEN knockdown‐induced nuclear FOXO1 protein reduction. Our study further showed that loss of FOXO1 increased cyclin D1 expression, leading to rat ASMC proliferation. Preincubation of rat ASMCs with pioglitazone, a PPAR‐γ activator, blocked TGF‐β1‐induced activation of Smad2/3 and its downstream targets changes of miR‐21, PTEN, Akt, FOXO1, and cyclin D1, resulting in the inhibition of rat ASMC proliferation. Our study suggests that the activation of PPAR‐γ inhibits rat ASMC proliferation by suppressing Smad–miR‐21 signaling and therefore has a potential value in the prevention and treatment of asthma by negatively modulating airway remodeling.

Clinicopathological and prognostic significance of leucine-rich repeats and immunoglobulin-like domains protein 1 (LRIG1) in malignant tumors: A meta-analysis

Background: Accumulating studies have demonstrated that the expression of leucine-rich repeats and immunoglobulin-like domains protein1 (LRIG1) is associated with various types of tumors. However, the conclusions of previous studies are not completely consistent. Thus, we conducted this meta-analysis to further explore the authentic value of LRIG1 in cancer outcome and clinical significance. Methods: We systematically searched electronic databases including PubMed, Web of Science, Embase, Chinese National Knowledge Infrastructure and Wanfang database. The hazard ratios (HRs), odds ratio (OR) and 95 % confidence intervals (CI) were calculated for effect measures. Results: 16 qualified studies involving 2043 patients with cancer were enrolled. High LRIG1 expression was associated with a good prognosis in malignant tumors (HR: 0.49, 95% CI=0.39-0.59). Furthermore, positive expression rate of LRIG1 was distinctly lower in cancer tissues than that in normal tissues (OR: 0.09, 95% CI=0.05-0.17). Positive LRIG1 expression was definitely related with smaller tumor size (OR: 1.64, 95% CI=1.11-2.42), early tumor stage (OR: 3.67, 95% CI=1.87-7.21), well degree of differentiation (OR: 4.35, 95% CI=2.12-8.93) and negative recurrence (OR: 0.29, 95% CI=0.16-0.53). Conclusions: LRIG1 expression was associated with a good prognosis in terms of overall survival (OS) and might act as a predictive factor for characteristics of cancer patients.

COP9 signalosome subunit 6 mediates PDGF -induced pulmonary arterial smooth muscle cells proliferation

Abstract Up‐regulation of mammalian COP9 signalosome subunit 6 (CSN6) and consequent reduction of SCF ubiquitin ligase substrate receptor &bgr;‐transduction repeat‐containing protein (&bgr;‐TrCP) have been shown to be associated with cancer cells proliferation. However, it is unclear whether CSN6 and &bgr;‐TrCP are also involved in PDGF‐induced pulmonary arterial smooth muscle cells (PASMCs) proliferation. This study aims to address this issue and further explore its potential mechanisms. Our results indicated that PDGF phosphorylated Akt, stimulated PASMCs proliferation; while inhibition of PDGF receptor (PDGFR) by imatinib prevented these effects. PDGF further up‐regulated CSN6 protein expression, this was accompanied with &bgr;‐TrCP reduction and increase of Cdc25A. Inhibition of PDGFR/PI3K/Akt signaling pathway reversed PDGF‐induced such changes and cell proliferation. Prior transfection of CSN6 siRNA blocked PDGF‐induced &bgr;‐TrCP down‐regulation, Cdc25A up‐regulation and cell proliferation. Furthermore, pre‐treatment of cells with MG‐132 also abolished PDGF‐induced &bgr;‐TrCP reduction, Cdc25A elevation and cell proliferation. In addition, pre‐depletion of Cdc25A by siRNA transfection suppressed PDGF‐induced PASMCs proliferation. Taken together, our study indicates that up‐regulation of CSN6 by PDGFR/PI3K/Akt signaling pathway decreases &bgr;‐TrCP by increasing its ubiquitinated degradation, and thereby increases the expression of Cdc25A, which promotes PDGF‐induced PASMCs proliferation. HighlightsCSN6 is up‐regulated in PASMCs stimulated with PDGF.Activated PDGFR/PI3K/Akt signaling pathway up‐regulats CSN6 in PDGF‐induced PASMCs.CSN6 increases &bgr;‐TrCP ubiquitinated degradation and thereby up‐regulates Cdc25A.Up‐regulation of Cdc25A promotes PDGF‐induced PASMCs proliferation.

Association of interleukin-17a rs2275913 gene polymorphism and asthma risk: a meta-analysis

Introduction Interleukin-17A (IL-17A), a pro-inflammatory cytokine, plays an important role in the pathogenesis of asthma. A number of studies have investigated the relationship between IL-17A rs2275913 polymorphism and risk of asthma. However, the results obtained are inconclusive. The aim of this meta-analysis is to clarify the relationship between IL-17A rs2275913 polymorphism and asthma risk. Material and methods Searches were conducted in PubMed, Web of Science, Elsevier, Google Scholar, Wanfang and Chinese National Knowledge Infrastructure (CNKI) databases, and data were extracted from eligible studies by two independent reviewers. The pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated. Publication bias, heterogeneity and sensitivity analysis were also assessed. Results Ten studies with a total of 5016 subjects were included. Overall, the results indicated a significant association between the IL-17A rs2275913 polymorphism and the risk of asthma (G vs. A: OR = 0.866, 95% CI: 0.789–0.951, p = 0.003; GG+GA vs. AA: OR = 0.752, 95% CI: 0.633–0.895, p = 0.001). In subgroup analysis by age and ethnicity, the G allele of rs2275913 in IL-17A was significantly associated with a reduced risk of asthma in children and Asians. Conclusions The results of this meta-analysis indicate that the G allele of rs2275913 in IL-17A is a protective factor for the development of asthma.

Sphingosine-1-phosphate induces airway smooth muscle cells proliferation, migration and contraction by modulating Hippo signaling effector YAP

Sphingosine-1-phosphate (S1P), a bioactive lipid, has been shown to be elevated in the airways of individuals with asthma and modulates the airway smooth muscle cell (ASMC) functions, yet its underlying molecular mechanisms are not completely understood. The aim of the present study is to address this issue. S1P induced yes-associated protein (YAP) dephosphorylation and nuclear localization via the S1PR2/3/Rho-associated protein kinase (ROCK) pathway, and this in turn increased forkhead box M1 (FOXM1) and cyclin D1 expression leading to ASMC proliferation, migration, and contraction. Pretreatment of cells with S1PR2 antagonist JTE013, S1PR3 antagonist CAY10444, or ROCK inhibitor Y27632 blocked S1P-induced alterations of YAP, FOXM1, cyclin D1, and ASMC proliferation, migration, and contraction. In addition, prior silencing of YAP or FOXM1 with siRNA reversed the effect of S1P on ASMC functions. Taken together, our study indicates that S1P stimulates ASMC proliferation, migration, and contraction by binding to S1PR2/3 and modulating ROCK/YAP/FOXM1 axis and suggests that targeting this pathway might have potential value in the management of asthma.