Key Laboratory of Arrhythmias

Laboratory of, China

Key Laboratory of Arrhythmias

Laboratory of, China
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Li J.,Key Laboratory of Arrhythmias | Li J.,Tongji University | Xu J.,Tongji University | Xiao J.,Key Laboratory of Arrhythmias | And 16 more authors.
Journal of Cellular and Molecular Medicine | Year: 2011

Abnormal activation of mitochondrial translocator protein (TSPO) contributes to arrhythmogenesis during cardiac metabolic compromise; however, its role in the antiarrhythmic activities of chronic hypoxia adaptation remains unclear. Our results demonstrated that 80% of normoxic rats developed ischaemic VF, whereas this condition was seldom observed in rats with 14 days of chronic intermittent hypobaric hypoxia (CIHH). TSPO stimulation or inhibition affected the arrhythmias incidence in normoxic rats, but did not change the CIHH-mediated antiarrhythmic effects. Abrupt and excessive elevation of TSPO activity was positively linked to ischaemic VF, and CIHH preserved TSPO activity during ischaemia. The preservation of TSPO activity by CIHH also contributed to the maintenance of intracellular Ca homeostasis. These results suggest that the blunt sensitivity of TSPO to ischaemic stress may be responsible for the antiarrhythmic effects by CIHH. © 2011 The Author Journal of Cellular and Molecular Medicine © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

Xiao J.,Key Laboratory of Arrhythmias | Xiao J.,Tongji University | Cao H.,Key Laboratory of Arrhythmias | Cao H.,Tongji University | And 17 more authors.
Journal of Cellular and Molecular Medicine | Year: 2011

Microtubule integrity is important in cardio-protection, and microtubule disruption has been implicated in the response to ischemia in cardiac myocytes. However, the effects of Taxol, a common microtubule stabilizer, are still unknown in ischemic ventricular arrhythmias. The arrhythmia model was established in isolated rat hearts by regional ischemia, and myocardial infarction model by ischemia/reperfusion. Microtubule structure was immunohistochemically measured. The potential mechanisms were studied by measuring reactive oxygen species (ROS), activities of oxidative enzymes, intracellular calcium concentration ([Ca 2+] i) and Ca 2+ transients by using fluorometric determination, spectrophotometric assays and Fura-2-AM and Fluo-3-AM, respectively. The expression and activity of sarcoplasmic reticulum Ca 2+-ATPase (SERCA2a) was also examined using real-time polymerase chain reaction, Western blot and pyruvate/Nicotinamide adenine dinucleotide-coupled reaction. Our data showed that Taxol (0.1, 0.3 and 1 μM) effectively reduced the number of ventricular premature beats and the incidence and duration of ventricular tachycardia. The infarct size was also significantly reduced by Taxol (1 μM). At the same time, Taxol preserved the microtubule structure, increased the activity of mitochondrial electron transport chain complexes I and III, reduced ROS levels, decreased the rise in [Ca 2+] i and preserved the amplitude and decay times of Ca 2+ transients during ischemia. In addition, SERCA2a activity was preserved by Taxol during ischemia. In summary, Taxol prevents ischemic ventricular arrhythmias likely through ameliorating abnormal calcium homeostasis and decreasing the level of ROS. This study presents evidence that Taxol may be a potential novel therapy for ischemic ventricular arrhythmias. © 2011 The Authors Journal of Cellular and Molecular Medicine © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

Lin X.,Johns Hopkins University | Lin X.,Zhejiang University | Lin X.,Key Laboratory of Arrhythmias | Liang H.-Y.,Johns Hopkins University | And 10 more authors.
Journal of Cardiovascular Translational Research | Year: 2013

We examined whether there is a relationship between repolarization abnormalities on electrocardiography (EKG) and deformation abnormalities by echocardiography. Analysis of baseline EKGs and mechanical (echo-based deformation) changes was performed in 128 patients with a clinical diagnosis of hypertrophic cardiomyopathy (HCM). Patients with left ventricular hypertrophy (LVH) or repolarization abnormalities had higher septal thickness when compared to patients with normal EKG. Patients with EKG evidence of LVH or QTc prolongation had lower systolic velocity, systolic strain, systolic strain rate, late diastolic velocity, and late diastolic strain rate than patients with a normal EKG. Patients with strain pattern or ST depression/T-wave inversion had lower systolic velocity, systolic strain, systolic strain rate, early diastolic velocity, and late diastolic velocity when compared to patients with normal EKGs. LVH and repolarization abnormalities on surface EKG are markers of impaired systolic and diastolic mechanics in HCM. © 2013 Springer Science+Business Media New York.

Qin Z.,Medical University of South Carolina | Qin Z.,Key Laboratory of Arrhythmias | Qin Z.,Tongji University | Dai L.,Medical University of South Carolina | And 6 more authors.
Leukemia | Year: 2011

The Kaposi's sarcoma-associated herpesvirus is the causative agent of primary effusion lymphoma (PEL), for which cytotoxic chemotherapy represents the standard of care. The high mortality associated with PEL may be explained in part by resistance of these tumors to chemotherapy. The membrane-bound glycoprotein emmprin (CD147) enhances chemoresistance in tumors through effects on transporter expression, trafficking and interactions. Interactions between hyaluronan and hyaluronan receptors on the cell surface also facilitate emmprin-mediated chemoresistance. Whether emmprin or hyaluronan-receptor interactions regulate chemotherapeutic resistance for virus-associated malignancies is unknown. Using human PEL tumor cells, we found that PEL sensitivity to chemotherapy is directly proportional to expression of emmprin, the lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) and a drug transporter known as the breast cancer resistance protein/ABCG2 (BCRP), and that emmprin, LYVE-1 and BCRP interact with each other and colocalize on the PEL cell surface. In addition, we found that emmprin induces chemoresistance in PEL cells through upregulation of BCRP expression, and RNA interference targeting of emmprin, LYVE-1 or BCRP enhances PEL cell apoptosis induced by chemotherapy. Finally, disruption of hyaluronan-receptor interactions using small hyaluronan oligosaccharides reduces expression of emmprin and BCRP while sensitizing PEL cells to chemotherapy. Collectively, these data support interdependent roles for emmprin, LYVE-1 and BCRP in chemotherapeutic resistance for PEL. © 2011 Macmillan Publishers Limited All rights reserved.

Yan B.,Tongji University | Yan B.,Harvard University | Kong M.,Harvard University | Chen S.,Harvard University | And 2 more authors.
Journal of Cellular Biochemistry | Year: 2010

Livin is a member of inhibitors of apoptosis proteins (IAPs) and overexpressed in transformed cells and several cancers. Although strategies to decrease Livin levels have been conducted for rational cancer therapy, the molecular mechanism controlling Livin expression in tumors has not been completely elucidated. Here, we show that vascular endothelial growth factor (VEGF) stimulation can increase Livin expression in HeLa cells or SK-MEL-28 cells. This response is independent of de novo gene transcription or changes in mRNA expression but occurs at protein expression levels. VEGF stimulation results in mTOR signaling activation which changes the phosphorylation status of 4E-BP1, the downstream of mTOR signaling, and ultimately contributes to the translation initiation of Livin protein. Livin silencing, Rapamycin alone or in combination with cytotoxic agent can reduce Livin protein levels, and decrease cells viability. Thus, ablation of Livin translation contributes to remove an anti-apoptotic mechanism potentially contributing to aggressive tumor behavior. Pharmacologic inhibition of VEGF/mTOR/Livin signaling may provide a novel strategy for cancer treatment. © 2010 Wiley-Liss, Inc.

Xiao J.,Key Laboratory of Arrhythmias | Xiao J.,Tongji University | Jing Z.-C.,Tongji University | Ellinor P.T.,Massachusetts General Hospital | And 21 more authors.
Journal of Translational Medicine | Year: 2011

Background: Acute pulmonary embolism (APE) remains a diagnostic challenge due to a variable clinical presentation and the lack of a reliable screening tool. MicroRNAs (miRNAs) regulate gene expression in a wide range of pathophysiologic processes. Circulating miRNAs are emerging biomarkers in heart failure, type 2 diabetes and other disease states; however, using plasma miRNAs as biomarkers for the diagnosis of APE is still unknown.Methods: Thirty-two APE patients, 32 healthy controls, and 22 non-APE patients (reported dyspnea, chest pain, or cough) were enrolled in this study. The TaqMan miRNA microarray was used to identify dysregulated miRNAs in the plasma of APE patients. The TaqMan-based miRNA quantitative real-time reverse transcription polymerase chain reactions were used to validate the dysregulated miRNAs. The receiver-operator characteristic (ROC) curve analysis was conducted to evaluate the diagnostic accuracy of the miRNA identified as the candidate biomarker.Results: Plasma miRNA-134 (miR-134) level was significantly higher in the APE patients than in the healthy controls or non-APE patients. The ROC curve showed that plasma miR-134 was a specific diagnostic predictor of APE with an area under the curve of 0.833 (95% confidence interval, 0.737 to 0.929; P < 0.001).Conclusions: Our findings indicated that plasma miR-134 could be an important biomarker for the diagnosis of APE. Because of this finding, large-scale investigations are urgently needed to pave the way from basic research to clinical utilization. © 2011 Xiao et al; licensee BioMed Central Ltd.

Xiao J.,Key Laboratory of Arrhythmias | Xiao J.,Tongji University | Liang D.,Key Laboratory of Arrhythmias | Liang D.,Tongji University | And 11 more authors.
Physiological Genomics | Year: 2011

The aim of this study was to investigate the microRNA (miRNA) signature in atrial fibrillation (AF) with mitral stenosis (MS). miRNA arrays were used to evaluate the expression signature of the right atrial appendages of healthy individuals (n = 9), patients with MS and AF (n = 9) and patients with MS without AF (n = 4). The results were validated with qRT-PCR analysis. GOmir was used to predict the potential miRNA targets and to analyze their functions. DIANA-mirPath was used to incorporate the miRNAs into path ways. miRNA arrays revealed that 136 and 96 miRNAs were expressed at different levels in MS patients with AF and in MS patients without AF, respectively, compared with healthy controls. More importantly, 28 miRNAs were expressed differently in the MS patients with AF compared with the MS patients without AF; of these miRNAs, miR-1202 was the most dysregulated. The unsupervised hierarchical clustering analysis based on the 28 differently expressed miRNAs showed that the heat map of miRNA expression categorized two well-defined clusters that corresponded to MS with AF and MS without AF. The qRT-PCR results correlated well with the microarray data. Bioinformatic analysis indicated the potential miRNA targets and molecular pathways. This study shows that there is a distinct miRNA expression signature in AF with MS. The findings may be useful for the development of therapeutic interventions that are based on rational target selection in these patients. © 2011 the American Physiological Society.

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