165 research outputs found

    Metabolic Stress-Induced Phosphorylation of KAP1 Ser473 Blocks Mitochondrial Fusion in Breast Cancer Cells

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    Mitochondrial dynamics during nutrient starvation of cancer cells likely exert profound effects on their capability for metastatic progression. Here, we report that KAP1 (TRIM28), a transcriptional coadaptor protein implicated in metastatic progression in breast cancer, is a pivotal regulator of mitochondrial fusion in glucose-starved cancer cells. Diverse metabolic stresses induced Ser473 phosphorylation of KAP1 (pS473-KAP1) in a ROS- and p38-dependent manner. Results from live-cell imaging and molecular studies revealed that during the first 6 to 8 hours of glucose starvation, mitochondria initially underwent extensive fusion, but then subsequently fragmented in a pS473-KAP1-dependent manner. Mechanistic investigations using phosphorylation-defective mutants revealed that KAP1 Ser473 phosphorylation limited mitochondrial hyperfusion in glucose-starved breast cancer cells, as driven by downregulation of the mitofusin protein MFN2, leading to reduced oxidative phosphorylation and ROS production. In clinical specimens of breast cancer, reduced expression of MFN2 corresponded to poor prognosis in patients. In a mouse xenograft model of human breast cancer, there was an association in the core region of tumors between MFN2 downregulation and the presence of highly fragmented mitochondria. Collectively, our results suggest that KAP1 Ser473 phosphorylation acts through MFN2 reduction to restrict mitochondrial hyperfusion, thereby contributing to cancer cell survival under conditions of sustained metabolic stress

    The long noncoding RNA THRIL regulates TNFalpha expression through its interaction with hnRNPL

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    Thousands of large intergenic noncoding RNAs (lincRNAs) have been identified in the mammalian genome, many of which have important roles in regulating a variety of biological processes. Here, we used a custom microarray to identify lincRNAs associated with activation of the innate immune response. A panel of 159 lincRNAs was found to be differentially expressed following innate activation of THP1 macrophages. Among them, linc1992 was shown to be expressed in many human tissues and was required for induction of TNFalpha expression. Linc1992 bound specifically to heterogenous nuclear ribonucleoprotein L (hnRNPL) and formed a functional linc1992-hnRNPL complex that regulated transcription of the TNFalpha gene by binding to its promoter. Transcriptome analysis revealed that linc1992 was required for expression of many immune-response genes, including other cytokines and transcriptional and posttranscriptional regulators of TNFalpha expression, and that knockdown of linc1992 caused dysregulation of these genes during innate activation of THP1 macrophages. Therefore, we named linc1992 THRIL (TNFalpha and hnRNPL related immunoregulatory LincRNA). Finally, THRIL expression was correlated with the severity of symptoms in patients with Kawasaki disease, an acute inflammatory disease of childhood. Collectively, our data provide evidence that lincRNAs and their binding proteins can regulate TNFalpha expression and may play important roles in the innate immune response and inflammatory diseases in humans

    Photothermal responsivity of van der Waals material-based nanomechanical resonators

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    Nanomechanical resonators made from van der Waals materials (vdW NMRs) provide a new tool for sensing absorbed laser power. The photothermal response of vdW NMRs, quantified from the resonant frequency shifts induced by optical absorption, is enhanced when incorporated in a Fabry-Perot (FP) interferometer. Along with the enhancement comes the dependence of the photothermal response on NMR displacement, which lacks investigation. Here, we address the knowledge gap by studying electromotively driven niobium diselenide drumheads fabricated on highly reflective substrates. We use a FP-mediated absorptive heating model to explain the measured variations of the photothermal response. The model predicts a higher magnitude and tuning range of photothermal responses on few-layer and monolayer NbSe2_{2} drumheads, which outperform other clamped vdW drum-type NMRs at a laser wavelength of 532532\,nm. Further analysis of the model shows that both the magnitude and tuning range of NbSe2_{2} drumheads scale with thickness, establishing a displacement-based framework for building bolometers using FP-mediated vdW NMRs.Comment: 7 pages, 4 figure

    Prevalence of complications among Chinese diabetic patients in urban primary care clinics: A cross-sectional study

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    Background: A territory-wide diabetes management program (Risk Assessment Management Program - RAMP) was recently established, providing comprehensive management for all diabetics, helping to delineate current level of control and complications prevalence among primary care diabetic patients in Hong Kong. Method. This cross-sectional study captured anonymous clinical data from RAMP patients. Data obtained include sociodemographic details, type of diabetes, illness duration, family history, drug usage, coexisting illnesses, diabetic complications and other clinical parameters. Results: Data from 15,856 type 2 diabetic patients were analyzed. 57.1% were above 60 years old, with mean disease duration of 7.3 years. Hypertension was the commonest coexisting chronic illness (57.6%). 30.2% and 61.8% have their systolic and diastolic pressure controlled to below 130 mmHg and 80 mmHg respectively. Over half (51.5%) had an HbA1c level of less than 7.0%. 88.4% did not achieve target lipid level. 15% were on diet control alone. Only 22.2% were on statins. In patients with microalbuminuria and macroalbuminuria, 40.7% and 54.5% were on angiotensin converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) respectively. 12.9%, 38.8% and 2.4% had diabetic retinopathy, nephropathy and neuropathy respectively. Overall, 37.9%, 7.3% and 0.4% had single, two and three concurrent microvascular complications respectively. Conclusion: The level of diabetic control is comparable with other developed countries. We demonstrated a high prevalence of microvascular complications among Chinese primary care patients despite achieving adequate HbA1c levels, highlighting the importance of managing all aspects of diabetes including weight, lipid and blood pressure. Efforts to improve holistic management must be tailored according to the needs of our population, with the challenges that the majority have low educational background and in the older age group. © 2014 Kung et al.; licensee BioMed Central Ltd.link_to_subscribed_fulltex

    Metabolic Stress-Induced Phosphorylation of KAP1 Ser473 Blocks Mitochondrial Fusion in Breast Cancer Cells

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    Mitochondrial dynamics during nutrient starvation of cancer cells likely exert profound effects on their capability for metastatic progression. Here, we report that KAP1 (TRIM28), a transcriptional coadaptor protein implicated in metastatic progression in breast cancer, is a pivotal regulator of mitochondrial fusion in glucose-starved cancer cells. Diverse metabolic stresses induced Ser473 phosphorylation of KAP1 (pS473-KAP1) in a ROS- and p38-dependent manner. Results from live-cell imaging and molecular studies revealed that during the first 6 to 8 hours of glucose starvation, mitochondria initially underwent extensive fusion, but then subsequently fragmented in a pS473-KAP1-dependent manner. Mechanistic investigations using phosphorylation-defective mutants revealed that KAP1 Ser473 phosphorylation limited mitochondrial hyperfusion in glucose-starved breast cancer cells, as driven by downregulation of the mitofusin protein MFN2, leading to reduced oxidative phosphorylation and ROS production. In clinical specimens of breast cancer, reduced expression of MFN2 corresponded to poor prognosis in patients. In a mouse xenograft model of human breast cancer, there was an association in the core region of tumors between MFN2 downregulation and the presence of highly fragmented mitochondria. Collectively, our results suggest that KAP1 Ser473 phosphorylation acts through MFN2 reduction to restrict mitochondrial hyperfusion, thereby contributing to cancer cell survival under conditions of sustained metabolic stress

    Nonlinear gyrokinetic simulations of the I-mode high confinement regime and comparisons with experimenta)

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    For the first time, nonlinear gyrokinetic simulations of I-mode plasmas are performed and compared with experiment. I-mode is a high confinement regime, featuring energy confinement similar to H-mode, but without enhanced particle and impurity particle confinement [D. G. Whyte et al., Nucl. Fusion 50, 105005 (2010)]. As a consequence of the separation between heat and particle transport, I-mode exhibits several favorable characteristics compared to H-mode. The nonlinear gyrokinetic code GYRO [J. Candy and R. E. Waltz, J Comput. Phys. 186, 545 (2003)] is used to explore the effects of E × B shear and profile stiffness in I-mode and compare with L-mode. The nonlinear GYRO simulations show that I-mode core ion temperature and electron temperature profiles are more stiff than L-mode core plasmas. Scans of the input E × B shear in GYRO simulations show that E × B shearing of turbulence is a stronger effect in the core of I-mode than L-mode. The nonlinear simulations match the observed reductions in long wavelength density fluctuation levels across the L-I transition but underestimate the reduction of long wavelength electron temperature fluctuation levels. The comparisons between experiment and gyrokinetic simulations for I-mode suggest that increased E × B shearing of turbulence combined with increased profile stiffness are responsible for the reductions in core turbulence observed in the experiment, and that I-mode resembles H-mode plasmas more than L-mode plasmas with regards to marginal stability and temperature profile stiffness.United States. Department of Energy (Contract No. DE-FC02-99ER54512-CMOD)United States. Department of Energy. Office of Science (Contract No. DE-AC02- 05CH11231

    Application of Frequent Itemsets Mining to Analyze Patterns of One-Stop Visits in Taiwan

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    BACKGROUND: The free choice of health care facilities without limitations on frequency of visits within the National Health Insurance in Taiwan gives rise to not only a high number of annual ambulatory visits per capita but also a unique "one-stop shopping"phenomenon, which refers to a patient' visits to several specialties of the same healthcare facility in one day. The visits to multiple physicians would increase the potential risk of polypharmacy. The aim of this study was to analyze the frequency and patterns of one-stop visits in Taiwan. METHODOLOGY/PRINCIPAL FINDINGS: The claims datasets of 1 million nationally representative people within Taiwan's National Health Insurance in 2005 were used to calculate the number of patients with one-stop visits. The frequent itemsets mining was applied to compute the combination patterns of specialties in the one-stop visits. Among the total 13,682,469 ambulatory care visits in 2005, one-stop visits occurred 144,132 times and involved 296,822 visits (2.2% of all visits) by 66,294 (6.6%) persons. People tended to have this behavior with age and the percentage reached 27.5% (5,662 in 20,579) in the age group ≥80 years. In general, women were more likely to have one-stop visits than men (7.2% vs. 6.0%). Internal medicine plus ophthalmology was the most frequent combination with a visited frequency of 3,552 times (2.5%), followed by cardiology plus neurology with 3,183 times (2.2%). The most frequent three-specialty combination, cardiology plus neurology and gastroenterology, occurred only 111 times. CONCLUSIONS/SIGNIFICANCE: Without the novel computational technique, it would be hardly possible to analyze the extremely diverse combination patterns of specialties in one-stop visits. The results of the study could provide useful information either for the hospital manager to set up integrated services or for the policymaker to rebuild the health care system

    Longitudinal seroepidemiologic study of the 2009 pandemic influenza A (H1N1) infection among health care workers in a children's hospital

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    <p>Abstract</p> <p>Background</p> <p>To probe seroepidemiology of the 2009 pandemic influenza A (H1N1) among health care workers (HCWs) in a children's hospital.</p> <p>Methods</p> <p>From August 2009 to March 2010, serum samples were drawn from 150 HCWs in a children's hospital in Taipei before the 2009 influenza A (H1N1) pandemic, before H1N1 vaccination, and after the pandemic. HCWs who had come into direct contact with 2009 influenza A (H1N1) patients or their clinical respiratory samples during their daily work were designated as a high-risk group. Antibody levels were determined by hemagglutination inhibition (HAI) assay. A four-fold or greater increase in HAI titers between any successive paired sera was defined as seroconversion, and factors associated with seroconversion were analyzed.</p> <p>Results</p> <p>Among the 150 HCWs, 18 (12.0%) showed either virological or serological evidence of 2009 pandemic influenza A (H1N1) infection. Of the 90 unvaccinated HCWs, baseline and post-pandemic seroprotective rates were 5.6% and 20.0%. Seroconversion rates among unvaccinated HCWs were 14.4% (13/90), 22.5% (9/40), and 8.0% (4/50) for total, high-risk group, and low-risk group, respectively. Multivariate analysis revealed being in the high-risk group is an independent risk factor associated with seroconversion.</p> <p>Conclusion</p> <p>The infection rate of 2009 pandemic influenza A (H1N1) in HCWs was moderate and not higher than that for the general population. The majority of unvaccinated HCWs remained susceptible. Direct contact of influenza patients and their respiratory samples increased the risk of infection.</p
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