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1004 Publications visible to you, out of a total of 1004
USP9X stabilizes XIAP to regulate mitotic cell death and chemoresistance in aggressive B-cell lymphoma.
GLA - German Lymphoma Alliance

Abstract (Expand)

The mitotic spindle assembly checkpoint (SAC) maintains genome stability and marks an important target for antineoplastic therapies. However, it has remained unclear how cells execute cell fate decisions … under conditions of SAC-induced mitotic arrest. Here, we identify USP9X as the mitotic deubiquitinase of the X-linked inhibitor of apoptosis protein (XIAP) and demonstrate that deubiquitylation and stabilization of XIAP by USP9X lead to increased resistance toward mitotic spindle poisons. We find that primary human aggressive B-cell lymphoma samples exhibit high USP9X expression that correlate with XIAP overexpression. We show that high USP9X/XIAP expression is associated with shorter event-free survival in patients treated with spindle poison-containing chemotherapy. Accordingly, aggressive B-cell lymphoma lines with USP9X and associated XIAP overexpression exhibit increased chemoresistance, reversed by specific inhibition of either USP9X or XIAP. Moreover, knockdown of USP9X or XIAP significantly delays lymphoma development and increases sensitivity to spindle poisons in a murine Emu-Myc lymphoma model. Together, we specify the USP9X-XIAP axis as a regulator of the mitotic cell fate decision and propose that USP9X and XIAP are potential prognostic biomarkers and therapeutic targets in aggressive B-cell lymphoma.

Authors: K. Engel, M. Rudelius, J. Slawska, L. Jacobs, B. Ahangarian Abhari, B. Altmann, J. Kurutz, A. Rathakrishnan, V. Fernandez-Saiz, A. Brunner, B. S. Targosz, F. Loewecke, C. J. Gloeckner, M. Ueffing, S. Fulda, M. Pfreundschuh, L. Trumper, W. Klapper, U. Keller, P. J. Jost, A. Rosenwald, C. Peschel, F. Bassermann

Date Published: 19th Jun 2016

Publication Type: Not specified

Human Diseases: B-cell lymphoma

Limited role for transforming growth factor-beta pathway activation-mediated escape from VEGF inhibition in murine glioma models.
GGN - German Glioma Network

Abstract (Expand)

BACKGROUND: The vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-beta pathways regulate key biological features of glioblastoma. Here we explore whether the TGF-beta … pathway, which promotes angiogenesis, invasiveness, and immunosuppression, acts as an escape pathway from VEGF inhibition. METHODS: The role of the TGF-beta pathway in escape from VEGF inhibition was assessed in vitro and in vivo and by gene expression profiling in syngeneic mouse glioma models. RESULTS: We found that TGF-beta is an upstream regulator of VEGF, whereas VEGF pathway activity does not alter the TGF-beta pathway in vitro. In vivo, single-agent activity was observed for the VEGF antibody B20-4.1.1 in 3 and for the TGF-beta receptor 1 antagonist LY2157299 in 2 of 4 models. Reduction of tumor volume and blood vessel density, but not induction of hypoxia, correlated with benefit from B20-4.1.1. Reduction of phosphorylated (p)SMAD2 by LY2157299 was seen in all models but did not predict survival. Resistance to B20 was associated with anti-angiogenesis escape pathway gene expression, whereas resistance to LY2157299 was associated with different immune response gene signatures in SMA-497 and GL-261 on transcriptomic profiling. The combination of B20 with LY2157299 was ineffective in SMA-497 but provided prolongation of survival in GL-261, associated with early suppression of pSMAD2 in tumor and host immune cells, prolonged suppression of angiogenesis, and delayed accumulation of tumor infiltrating microglia/macrophages. CONCLUSIONS: Our study highlights the biological heterogeneity of murine glioma models and illustrates that cotargeting of the VEGF and TGF-beta pathways might lead to improved tumor control only in subsets of glioblastoma.

Authors: D. Mangani, M. Weller, E. Seyed Sadr, E. Willscher, K. Seystahl, G. Reifenberger, G. Tabatabai, H. Binder, H. Schneider

Date Published: 12th Jun 2016

Publication Type: Not specified

Human Diseases: glioblastoma multiforme

Normative values of the Epworth Sleepiness Scale (ESS), derived from a large German sample.
LIFE Adult

Abstract (Expand)

PURPOSE: Daytime sleepiness is associated with several medical problems. The aim of this paper is to provide normative values for one of the most often used questionnaires measuring daytime sleepiness, … the Epworth Sleepiness Scale (ESS). METHODS: A large sample of 9711 people from the German general population took part in this study. In addition to the ESS, several other questionnaires were used, and sociodemographic and behavioral factors were recorded. RESULTS: Normative values for the ESS are given. According to the generally accepted criterion ESS > 10, 23 % of the sample showed excessive daytime sleepiness. Males reported significantly more daytime sleepiness than females (effect size d = 0.19). In the age range of 40-80 years, a continuous decline of daytime sleepiness was observed. Psychometric properties of the ESS were good. Alcohol intake and nicotine consumption were marginally associated with daytime sleepiness, and obese people reported significantly more sleepiness than people of normal weight (OR = 1.39). CONCLUSIONS: The normative tables allow clinicians and researchers to assess the degree of their patients' daytime sleepiness, especially in the upper range of scores.

Authors: C. Sander, U. Hegerl, K. Wirkner, N. Walter, R. D. Kocalevent, K. Petrowski, H. Glaesmer, A. Hinz

Date Published: 29th May 2016

Publication Type: Journal article

Optimization-Based Speckle Tracking Algorithm for Left Ventricle Strain Estimation: A Feasibility Study.
LIFE Adult

Abstract (Expand)

Speckle tracking echocardiography (STE) is a widespread method for calculating myocardial strains and estimating left ventricle function. Since echocardiographic clips are corrupted by speckle decorrelation … noise, resulting in irregular, nonphysiological tissue displacement fields, smoothing is performed on the displacement data, affecting the strain results. Thus, strain results may depend on the specific implementations of 2-D STE, as well as other systems' characteristics of the various vendors. A novel algorithm (called K-SAD) is introduced, which integrates the physiological constraint of smoothness of the displacement field into an optimization process. Simulated B-mode clips, modeling healthy and abnormal cases, were processed by K-SAD. Peak global and subendocardial longitudinal strains, as well as regional strains, were calculated. In addition, 410 healthy subjects were also processed. The results of K-SAD are compared with those of one of the leading commercial product. K-SAD provides global mid-wall strain values, as well as subendocardial and regional strain values, all in good agreement with the ground-truth-simulated phantom data. K-SAD peak global longitudinal systolic strain values for 410 healthy subjects are quite similar for the different regions: - 17.02 +/- 4.02%, - 19.00 +/- 3.45%, and - 19.72 +/- 5.06% at the basal, mid, and apical regions, respectively. Improved performance under noisy conditions was demonstrated by comparing a subgroup of 40 subjects with the best image quality with the remaining 370 cohort: K-SAD provides statistically similar global and regional results for the two cohorts. Our study indicates that the sensitivity of strain values to speckle noise, caused by the post block-matching weighted smoothing, can be significantly reduced and accuracy enhanced by employing an integrated one-stage, physiologically constrained optimization process.

Authors: H. Khamis, S. Shimoni, A. Hagendorff, N. Smirin, Z. Friedman, D. Adam

Date Published: 24th May 2016

Publication Type: Journal article

Cartography of Pathway Signal Perturbations Identifies Distinct Molecular Pathomechanisms in Malignant and Chronic Lung Diseases.
LHA - Leipzig Health Atlas

Abstract (Expand)

Lung diseases are described by a wide variety of developmental mechanisms and clinical manifestations. Accurate classification and diagnosis of lung diseases are the bases for development of effective … treatments. While extensive studies are conducted toward characterization of various lung diseases at molecular level, no systematic approach has been developed so far. Here we have applied a methodology for pathway-centered mining of high throughput gene expression data to describe a wide range of lung diseases in the light of shared and specific pathway activity profiles. We have applied an algorithm combining a Pathway Signal Flow (PSF) algorithm for estimation of pathway activity deregulation states in lung diseases and malignancies, and a Self Organizing Maps algorithm for classification and clustering of the pathway activity profiles. The analysis results allowed clearly distinguish between cancer and non-cancer lung diseases. Lung cancers were characterized by pathways implicated in cell proliferation, metabolism, while non-malignant lung diseases were characterized by deregulations in pathways involved in immune/inflammatory response and fibrotic tissue remodeling. In contrast to lung malignancies, chronic lung diseases had relatively heterogeneous pathway deregulation profiles. We identified three groups of interstitial lung diseases and showed that the development of characteristic pathological processes, such as fibrosis, can be initiated by deregulations in different signaling pathways. In conclusion, this paper describes the pathobiology of lung diseases from systems viewpoint using pathway centered high-dimensional data mining approach. Our results contribute largely to current understanding of pathological events in lung cancers and non-malignant lung diseases. Moreover, this paper provides new insight into molecular mechanisms of a number of interstitial lung diseases that have been studied to a lesser extent.

Authors: A. Arakelyan, L. Nersisyan, M. Petrek, H. Loffler-Wirth, H. Binder

Date Published: 21st May 2016

Publication Type: Not specified

Human Diseases: lung disease

A Biomathematical Model of Pneumococcal Lung Infection and Antibiotic Treatment in Mice
Genetical Statistics and Systems Biology

Abstract (Expand)

Pneumonia is considered to be one of the leading causes of death worldwide. The outcome depends on both, proper antibiotic treatment and the effectivity of the immune response of the host. However, due … to the complexity of the immunologic cascade initiated during infection, the latter cannot be predicted easily. We construct a biomathematical model of the murine immune response during infection with pneumococcus aiming at predicting the outcome of antibiotic treatment. The model consists of a number of non-linear ordinary differential equations describing dynamics of pneumococcal population, the inflammatory cytokine IL-6, neutrophils and macrophages fighting the infection and destruction of alveolar tissue due to pneumococcus. Equations were derived by translating known biological mechanisms and assuming certain response kinetics. Antibiotic therapy is modelled by a transient depletion of bacteria. Unknown model parameters were determined by fitting the predictions of the model to data sets derived from mice experiments of pneumococcal lung infection with and without antibiotic treatment. Time series of pneumococcal population, debris, neutrophils, activated epithelial cells, macrophages, monocytes and IL-6 serum concentrations were available for this purpose. The antibiotics Ampicillin and Moxifloxacin were considered. Parameter fittings resulted in a good agreement of model and data for all experimental scenarios. Identifiability of parameters is also estimated. The model can be used to predict the performance of alternative schedules of antibiotic treatment. We conclude that we established a biomathematical model of pneumococcal lung infection in mice allowing predictions regarding the outcome of different schedules of antibiotic treatment. We aim at translating the model to the human situation in the near future.

Authors: Sibylle Schirm, Peter Ahnert, Sandra Wienhold, Holger Mueller-Redetzky, Geraldine Nouailles-Kursar, Markus Loeffler, Martin Witzenrath, Markus Scholz

Date Published: 19th May 2016

Publication Type: Journal article

Neural processing of negative emotional stimuli and the influence of age, sex and task-related characteristics.
LIFE Adult

Abstract (Expand)

Negative emotional stimuli are particularly salient events that receive privileged access to neurocognitive resources. At the neural level, the processing of negative stimuli relies on a set of sensory, … limbic, and prefrontal areas. However, controversies exist on how demographic and task-related characteristics modulate this brain pattern. Here, we used activation likelihood estimation (ALE) meta-analysis and replicator dynamics to investigate the processing of negative visual stimuli in healthy adults. Our findings endorse the central role of the amygdala. This result might reflect how this structure modulates perceptual and attentional mechanisms in response to emotional stimuli. Additionally, we characterize how the neural processing of negative visual stimuli is influenced by the demographic factors of age and sex as well as by task-related characteristics like stimulus type, emotion category, and task instruction, with the amygdala showing comparable engagement across different sexes, stimulus types, and task instructions. Our findings practically inform experimentation in the affective neurosciences but also suggest brain circuits for neurobiological investigations of affective symptomatology.

Authors: I. Garcia-Garcia, J. Kube, M. Gaebler, A. Horstmann, A. Villringer, J. Neumann

Date Published: 12th May 2016

Publication Type: Not specified

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