Publications by authors named "Nadine Schmidt"

41 Publications

The Functional Availability of Arterial Kv7 Channels Is Suppressed Considerably by Large-Conductance Calcium-Activated Potassium Channels in 2- to 3-Month Old but Not in 10- to 15-Day Old Rats.

Front Physiol 2020 15;11:597395. Epub 2020 Dec 15.

European Center for Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.

Background: Voltage-gated potassium (Kv) channels, especially Kv7 channels, are major potassium channels identified in vascular smooth muscle cells with a great, albeit differential functional impact in various vessels. Vascular smooth muscle Kv7 channels always coexist with other K channels, in particular with BK channels. BK channels differ in the extent to which they influence vascular contractility. Whether this difference also causes the variability in the functional impact of Kv7 channels is unknown. Therefore, this study addressed the hypothesis that the functional impact of Kv7 channels depends on BK channels.

Experimental Approach: Experiments were performed on young and adult rat and arteries using real-time PCR as well as pressure and wire myography.

Key Results: Several subfamily members of Kv7 (KCNQ) and BK channels were expressed in saphenous and gracilis arteries: the highest expression was observed for BKα, BKβ1 and KCNQ4. Arterial contractility was assessed with methoxamine-induced contractions and pressure-induced myogenic responses. In vessels of adult rats, inhibition of Kv7 channels or BK channels by XE991 or IBTX, respectively enhanced arterial contractility to a similar degree, whereas activation of Kv7 channels or BK channels by retigabine or NS19504, respectively reduced arterial contractility to a similar degree. Further, IBTX increased both the contractile effect of XE991 and the anticontractile effect of retigabine, whereas NS19504 reduced the effect of retigabine and impaired the effect of XE991. In vessels of young rats, inhibition of Kv7 channels by XE991 enhanced arterial contractility much stronger than inhibition of BK channels by IBTX, whereas activation of Kv7 by retigabine reduced arterial contractility to a greater extent than activation of BK channels by NS19504. Further, IBTX increased the anticontractile effect of retigabine but not the contractile effect of XE991, whereas NS19504 reduced the effect of retigabine and impaired the effect of XE991.

Conclusion: Kv7 and BK channels are expressed in young and adult rat arteries and function as negative feedback modulators in the regulation of contractility of these arteries. Importantly, BK channels govern the extent of functional impact of Kv7 channels. This effect depends on the relationship between the functional activities of BK and Kv7 channels.
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http://dx.doi.org/10.3389/fphys.2020.597395DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7770149PMC
December 2020

Destabilization of Long Astral Microtubules via Cdk1-Dependent Removal of GTSE1 from Their Plus Ends Facilitates Prometaphase Spindle Orientation.

Curr Biol 2021 Feb 16;31(4):766-781.e8. Epub 2020 Dec 16.

Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany. Electronic address:

The precise regulation of microtubule dynamics over time and space in dividing cells is critical for several mitotic mechanisms that ultimately enable cell proliferation, tissue organization, and development. Astral microtubules, which extend from the centrosome toward the cell cortex, must be present for the mitotic spindle to properly orient, as well as for the faithful execution of anaphase and cytokinesis. However, little is understood about how the dynamic properties of astral microtubules are regulated spatiotemporally, or the contribution of astral microtubule dynamics to spindle positioning. The mitotic regulator Cdk1-CyclinB promotes destabilization of centrosomal microtubules and increased microtubule dynamics as cells enter mitosis, but how Cdk1 activity modulates astral microtubule stability, and whether it impacts spindle positioning, is unknown. Here, we uncover a mechanism revealing that Cdk1 destabilizes astral microtubules in prometaphase and thereby influences spindle reorientation. Phosphorylation of the EB1-dependent microtubule plus-end tracking protein GTSE1 by Cdk1 in early mitosis abolishes its interaction with EB1 and recruitment to microtubule plus ends. Loss of Cdk1 activity, or mutation of phosphorylation sites in GTSE1, induces recruitment of GTSE1 to growing microtubule plus ends in mitosis. This decreases the catastrophe frequency of astral microtubules and causes an increase in the number of long astral microtubules reaching the cell cortex, which restrains the ability of cells to reorient spindles along the long cellular axis in early mitosis. Astral microtubules thus must not only be present but also dynamic to allow the spindle to reorient, a state assisted by selective destabilization of long astral microtubules via Cdk1.
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http://dx.doi.org/10.1016/j.cub.2020.11.040DOI Listing
February 2021

ESI mutagenesis: a one-step method for introducing mutations into bacterial artificial chromosomes.

Life Sci Alliance 2021 02 8;4(2). Epub 2020 Dec 8.

Max Planck Institute of Molecular Physiology, Dortmund, Germany

Bacterial artificial chromosome (BAC)-based transgenes have emerged as a powerful tool for controlled and conditional interrogation of protein function in higher eukaryotes. Although homologous recombination-based recombineering methods have streamlined the efficient integration of protein tags onto BAC transgenes, generating precise point mutations has remained less efficient and time-consuming. Here, we present a simplified method for inserting point mutations into BAC transgenes requiring a single recombineering step followed by antibiotic selection. This technique, which we call exogenous/synthetic intronization (ESI) mutagenesis, relies on co-integration of a mutation of interest along with a selectable marker gene, the latter of which is harboured in an artificial intron adjacent to the mutation site. Cell lines generated from ESI-mutated BACs express the transgenes equivalently to the endogenous gene, and all cells efficiently splice out the synthetic intron. Thus, ESI mutagenesis provides a robust and effective single-step method with high precision and high efficiency for mutating BAC transgenes.
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http://dx.doi.org/10.26508/lsa.202000836DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7756954PMC
February 2021

Investigating a new tablet-based telerehabilitation app in patients with aphasia: a randomised, controlled, evaluator-blinded, multicentre trial protocol.

BMJ Open 2020 11 11;10(11):e037702. Epub 2020 Nov 11.

Gerontechnology and Rehabilitation Group, University of Bern, Bern, Switzerland

Introduction: Aphasia is a common language disorder acquired after stroke that reduces the quality of life of affected patients. The impairment is frequently accompanied by a deficit in cognitive functions. The state-of-the-art therapy is speech and language therapy but recent findings highlight positive effects of high-frequency therapy. Telerehabilitation has the potential to enable high-frequency therapy for patients at home. This study investigates the effects of high-frequency telerehabilitation speech and language therapy (teleSLT) on language functions in outpatients with aphasia compared with telerehabilitative cognitive training. We hypothesise that patients training with high-frequency teleSLT will show higher improvement in language functions and quality of life compared with patients with high-frequency tele-rehabilitative cognitive training (teleCT).

Methods And Analysis: This study is a randomised controlled, evaluator-blinded multicentre superiority trial comparing the outcomes following either high-frequency teleSLT or teleCT. A total of 100 outpatients with aphasia will be recruited and assigned in a 1:1 ratio stratified by trial site and severity of impairment to one of two parallel groups. Both groups will train over a period of 4 weeks for 2 hours per day. Patients in the experimental condition will devote 80% of their training time to teleSLT and the remaining 20% (24 min/day) to teleCT, vice versa for patients in the control condition. The primary outcome measure is the understandability of verbal communication on the Amsterdam Nijmegen Everyday Language Test and secondary outcome measures are intelligibility of the verbal communication, impairment of receptive and expressive language functions, confrontation naming. Other outcomes measures are quality of life and acceptance (usability and subjective experience) of the teleSLT system.

Ethics And Dissemination: This study is approved by the Ethics Committee Bern (ID 2016-01577). Results will be submitted to a peer-reviewed journal.

Trial Registration Number: NCT03228264.
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http://dx.doi.org/10.1136/bmjopen-2020-037702DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7661375PMC
November 2020

TASK-1 channel blockade by AVE1231 increases vasocontractile responses and BP in 1- to 2-week-old but not adult rats.

Br J Pharmacol 2020 Nov 24;177(22):5148-5162. Epub 2020 Sep 24.

Centre for Biomedicine and Medical Technology Mannheim (CBTM) and European Center of Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany.

Background And Purpose: The vasomotor role of K2P potassium channels during early postnatal development has never been investigated. We tested the hypothesis that TASK-1 channel (K2P family member) contribution to arterial vascular tone and BP is higher in the early postnatal period than in adulthood.

Experimental Approach: We studied 10- to 15-day-old ("young") and 2- to 3-month-old ("adult") male rats performing digital PCR (dPCR) (using endothelium-intact saphenous arteries), isometric myography, sharp microelectrode technique, quantitative PCR (qPCR) and Western blotting (using endothelium-denuded saphenous arteries), and arterial pressure measurements under urethane anaesthesia.

Key Results: We found mRNA of Kcnk1-Kcnk7, Kcnk12, and Kcnk13 genes to be expressed in rat saphenous artery, and Kcnk3 (TASK-1) and Kcnk6 (TWIK-2) were most abundant in both age groups. The TASK-1 channel blocker AVE1231 (1 μmol·L ) prominently depolarized arterial smooth muscle and increased basal tone level and contractile responses to methoxamine of arteries from young rats but had almost no effect in adult rats. The level of TASK-1 mRNA and protein expression was higher in arteries from young compared with adult rats. Importantly, intravenous administration of AVE1231 (4 mg·kg ) had no effect on mean arterial pressure in adult rats but prominently raised it in young rats.

Conclusion And Implications: We showed that TASK-1 channels are important for negative feedback regulation of vasocontraction in young but not adult rats. The influence of TASK-1 channels most likely contributes to low BP level at perinatal age.
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http://dx.doi.org/10.1111/bph.15249DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7589011PMC
November 2020

IL-13 as Target to Reduce Cholestasis and Dysbiosis in Knockout Mice.

Cells 2020 08 24;9(9). Epub 2020 Aug 24.

Department of Gastroenterology, Justus-Liebig-University, D-35392 Giessen, Germany.

The Th2 cytokine IL-13 is involved in biliary epithelial injury and liver fibrosis in patients as well as in animal models. The aim of this study was to investigate IL-13 as a therapeutic target during short term and chronic intrahepatic cholestasis in an knockout mouse model (). Lack of IL-13 protected mice transiently from cholestasis. This decrease in serum bile acids was accompanied by an enhanced excretion of bile acids and a normalization of fecal bile acid composition. In double knockout mice, bacterial translocation to the liver was significantly reduced and the intestinal microbiome resembled the commensal composition in wild type animals. In addition, 52-week-old mice showed significantly reduced hepatic fibrosis. mice devoid of IL-13 transiently improved cholestasis and converted the composition of the gut microbiota towards healthy conditions. This highlights IL-13 as a potential therapeutic target in biliary diseases.
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http://dx.doi.org/10.3390/cells9091949DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564366PMC
August 2020

Effects of intensive care unit ambient sounds on healthcare professionals: results of an online survey and noise exposure in an experimental setting.

Intensive Care Med Exp 2020 Jul 23;8(1):34. Epub 2020 Jul 23.

Department of Intensive Care Medicine, University Hospital Bern (Inselspital), University of Bern, CH-3010, Bern, Switzerland.

Background: Noise levels on intensive care units (ICUs) are typically elevated. While many studies reported negative effects of ICU ambient sounds on patients, only few investigated noise as a factor to influence well-being or performance in healthcare professionals.

Methods: An online survey in the German-speaking part of Switzerland was conducted to assess how ICU soundscapes are subjectively perceived by healthcare professionals. The questionnaire was answered by 348 participants. Additionally, effects of noise on working memory performance were evaluated in an experimental noise exposure setting. Twenty-six healthcare professionals and 27 healthy controls performed a 2-back object-location task while being exposed to either ICU or pink noise.

Results: Survey results demonstrate that a majority of participants was aware of heightened noise levels. Participants reported that mostly well-being, performance, and attention could be reduced, along with subjective annoyance and fatigue by ICU ambient sounds. Although no significant effects of noise exposure on working memory performance was observed, self-assessments revealed significantly higher stress levels, increased annoyance and distraction ratings as well as decreased confidence in performance after ICU-noise exposure.

Conclusion: Subjective assessments indicate that heightened noise levels on ICUs induce annoyance, with heightened stress levels, impaired well-being, and reduced performance being potential consequences. Empirical evidence with objective and physiological measures is warranted.
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http://dx.doi.org/10.1186/s40635-020-00321-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7376325PMC
July 2020

Chemosensory Cell-Derived Acetylcholine Drives Tracheal Mucociliary Clearance in Response to Virulence-Associated Formyl Peptides.

Immunity 2020 04;52(4):683-699.e11

Institute for Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University, 35385 Giessen, Germany. Electronic address:

Mucociliary clearance through coordinated ciliary beating is a major innate defense removing pathogens from the lower airways, but the pathogen sensing and downstream signaling mechanisms remain unclear. We identified virulence-associated formylated bacterial peptides that potently stimulated ciliary-driven transport in the mouse trachea. This innate response was independent of formyl peptide and taste receptors but depended on key taste transduction genes. Tracheal cholinergic chemosensory cells expressed these genes, and genetic ablation of these cells abrogated peptide-driven stimulation of mucociliary clearance. Trpm5-deficient mice were more susceptible to infection with a natural pathogen, and formylated bacterial peptides were detected in patients with chronic obstructive pulmonary disease. Optogenetics and peptide stimulation revealed that ciliary beating was driven by paracrine cholinergic signaling from chemosensory to ciliated cells operating through muscarinic M3 receptors independently of nerves. We provide a cellular and molecular framework that defines how tracheal chemosensory cells integrate chemosensation with innate defense.
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http://dx.doi.org/10.1016/j.immuni.2020.03.005DOI Listing
April 2020

Clathrin's adaptor interaction sites are repurposed to stabilize microtubules during mitosis.

J Cell Biol 2020 02;219(2)

Max Planck Institute of Molecular Physiology, Dortmund, Germany.

Clathrin ensures mitotic spindle stability and efficient chromosome alignment, independently of its vesicle trafficking function. Although clathrin localizes to the mitotic spindle and kinetochore fiber microtubule bundles, the mechanisms by which clathrin stabilizes microtubules are unclear. We show that clathrin adaptor interaction sites on clathrin heavy chain (CHC) are repurposed during mitosis to directly recruit the microtubule-stabilizing protein GTSE1 to the spindle. Structural analyses reveal that these sites interact directly with clathrin-box motifs on GTSE1. Disruption of this interaction releases GTSE1 from spindles, causing defects in chromosome alignment. Surprisingly, this disruption destabilizes astral microtubules, but not kinetochore-microtubule attachments, and chromosome alignment defects are due to a failure of chromosome congression independent of kinetochore-microtubule attachment stability. GTSE1 recruited to the spindle by clathrin stabilizes microtubules by inhibiting the microtubule depolymerase MCAK. This work uncovers a novel role of clathrin adaptor-type interactions to stabilize nonkinetochore fiber microtubules to support chromosome congression, defining for the first time a repurposing of this endocytic interaction mechanism during mitosis.
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http://dx.doi.org/10.1083/jcb.201907083DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7041688PMC
February 2020

Large B - Cell Lymphoma of the Leg - Unfavourable Course with Rituximab/Bendamustin.

Open Access Maced J Med Sci 2019 Sep 30;7(18):3006-3008. Epub 2019 Jun 30.

Department of Dermatology, University of Rome "G. Marconi", Rome, Italy.

Background: Cutaneous B-cell lymphomas represent about 25% of all cutaneous lymphomas. Peripheral diffuse large B-cell lymphoma of the leg type is the most aggressive subtype seen mainly in elderly patients. Treatment is not standardised.

Case Report: An 87-year-old female patient was presented in May 2018 because of the development of painless subcutaneous nodules on the legs since late 2017. On examination, we observed up to 5 cm large erythematous nodules on the legs and a smaller plaque in the left submammary fold. The histology of a skin demonstrated tumour infiltrate that was separated from the overlying epidermis by a grenz zone. It consisted of densely packed, blastoid lymphocytic cells with numerous, and some atypical mitoses. The cells were positive for CD20, CD79A and CD5. Almost 100% of the cells were labelled with Ki67. The diagnosis of a diffuse large B-cell lymphoma (PCLBCL-LT) of the leg was confirmed. Histologic analysis of a bone marrow biopsy demonstrated a hypercellular bone marrow without malignant lymphatic infiltrates. Diagnostic ultrasound of cervical nodes and computerised tomography (CT) scans (native and with contrast medium) of head, neck and trunk excluded an extracutaneous manifestation of the PCLBCL-LT. Treatment with rituximab plus bendamustibe was initiated, but tumour progress was noted after the second course. Suggested palliative therapy with radiation and rituximab was refused. The patient died 7 months after diagnosis.

Conclusions: Although some trials suggested a beneficial effect of immuno-chemotherapy, the prognosis of (PCLBCL-LT) remains poor. Standardised treatment is missing due to the relative rarity of this malignancy.
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http://dx.doi.org/10.3889/oamjms.2019.565DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6910811PMC
September 2019

The German National Registry of Primary Immunodeficiencies (2012-2017).

Authors:
Sabine M El-Helou Anika-Kerstin Biegner Sebastian Bode Stephan R Ehl Maximilian Heeg Maria E Maccari Henrike Ritterbusch Carsten Speckmann Stephan Rusch Raphael Scheible Klaus Warnatz Faranaz Atschekzei Renata Beider Diana Ernst Stev Gerschmann Alexandra Jablonka Gudrun Mielke Reinhold E Schmidt Gesine Schürmann Georgios Sogkas Ulrich H Baumann Christian Klemann Dorothee Viemann Horst von Bernuth Renate Krüger Leif G Hanitsch Carmen M Scheibenbogen Kirsten Wittke Michael H Albert Anna Eichinger Fabian Hauck Christoph Klein Anita Rack-Hoch Franz M Sollinger Anne Avila Michael Borte Stephan Borte Maria Fasshauer Anja Hauenherm Nils Kellner Anna H Müller Anett Ülzen Peter Bader Shahrzad Bakhtiar Jae-Yun Lee Ursula Heß Ralf Schubert Sandra Wölke Stefan Zielen Sujal Ghosh Hans-Juergen Laws Jennifer Neubert Prasad T Oommen Manfred Hönig Ansgar Schulz Sandra Steinmann Klaus Schwarz Gregor Dückers Beate Lamers Vanessa Langemeyer Tim Niehues Sonu Shai Dagmar Graf Carmen Müglich Marc T Schmalzing Eva C Schwaneck Hans-Peter Tony Johannes Dirks Gabriele Haase Johannes G Liese Henner Morbach Dirk Foell Antje Hellige Helmut Wittkowski Katja Masjosthusmann Michael Mohr Linda Geberzahn Christian M Hedrich Christiane Müller Angela Rösen-Wolff Joachim Roesler Antje Zimmermann Uta Behrends Nikolaus Rieber Uwe Schauer Rupert Handgretinger Ursula Holzer Jörg Henes Lothar Kanz Christoph Boesecke Jürgen K Rockstroh Carolynne Schwarze-Zander Jan-Christian Wasmuth Dagmar Dilloo Brigitte Hülsmann Stefan Schönberger Stefan Schreiber Rainald Zeuner Tobias Ankermann Philipp von Bismarck Hans-Iko Huppertz Petra Kaiser-Labusch Johann Greil Donate Jakoby Andreas E Kulozik Markus Metzler Nora Naumann-Bartsch Bettina Sobik Norbert Graf Sabine Heine Robin Kobbe Kai Lehmberg Ingo Müller Friedrich Herrmann Gerd Horneff Ariane Klein Joachim Peitz Nadine Schmidt Stefan Bielack Ute Groß-Wieltsch Carl F Classen Jessica Klasen Peter Deutz Dirk Kamitz Lisa Lassay Klaus Tenbrock Norbert Wagner Benedikt Bernbeck Bastian Brummel Eusebia Lara-Villacanas Esther Münstermann Dominik T Schneider Nadine Tietsch Marco Westkemper Michael Weiß Christof Kramm Ingrid Kühnle Silke Kullmann Hermann Girschick Christof Specker Elisabeth Vinnemeier-Laubenthal Henriette Haenicke Claudia Schulz Lothar Schweigerer Thomas G Müller Martina Stiefel Bernd H Belohradsky Veronika Soetedjo Gerhard Kindle Bodo Grimbacher

Front Immunol 2019 19;10:1272. Epub 2019 Jul 19.

Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

The German PID-NET registry was founded in 2009, serving as the first national registry of patients with primary immunodeficiencies (PID) in Germany. It is part of the European Society for Immunodeficiencies (ESID) registry. The primary purpose of the registry is to gather data on the epidemiology, diagnostic delay, diagnosis, and treatment of PIDs. Clinical and laboratory data was collected from 2,453 patients from 36 German PID centres in an online registry. Data was analysed with the software Stata® and Excel. The minimum prevalence of PID in Germany is 2.72 per 100,000 inhabitants. Among patients aged 1-25, there was a clear predominance of males. The median age of living patients ranged between 7 and 40 years, depending on the respective PID. Predominantly antibody disorders were the most prevalent group with 57% of all 2,453 PID patients (including 728 CVID patients). A gene defect was identified in 36% of patients. Familial cases were observed in 21% of patients. The age of onset for presenting symptoms ranged from birth to late adulthood (range 0-88 years). Presenting symptoms comprised infections (74%) and immune dysregulation (22%). Ninety-three patients were diagnosed without prior clinical symptoms. Regarding the general and clinical diagnostic delay, no PID had undergone a slight decrease within the last decade. However, both, SCID and hyper IgE- syndrome showed a substantial improvement in shortening the time between onset of symptoms and genetic diagnosis. Regarding treatment, 49% of all patients received immunoglobulin G (IgG) substitution (70%-subcutaneous; 29%-intravenous; 1%-unknown). Three-hundred patients underwent at least one hematopoietic stem cell transplantation (HSCT). Five patients had gene therapy. The German PID-NET registry is a precious tool for physicians, researchers, the pharmaceutical industry, politicians, and ultimately the patients, for whom the outcomes will eventually lead to a more timely diagnosis and better treatment.
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http://dx.doi.org/10.3389/fimmu.2019.01272DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6659583PMC
October 2020

Copper and zinc ions govern the trans-directed dimerization of APP family members in multiple ways.

J Neurochem 2019 12 6;151(5):626-641. Epub 2019 Jun 6.

Division of Human Biology and Human Genetics, Technische Universität Kaiserslautern (TUK), Kaiserslautern, Germany.

The amyloid precursor protein (APP) and its homologs amyloid precursor-like protein 1 (APLP1) and APLP2 have central physiological functions in transcellular adhesion that depend on copper and zinc mediated trans-directed dimerization of the extracellular domains E1 and E2. Copper binds to three distinct sites in APP, one in the copper binding (CuBD) and growth factor-like (GFLD) domains each within E1, and one in the E2 domain. For APLP1 and APLP2, metal binding has so far only been shown for the E2 domain. Zinc binding has been reported for all APP family members to a unique site in the E2 domain and an additional site essential for APLP1 E2 domain trans-dimerization. Using isothermal titration calorimetry, co-immunoprecipitation, and in vitro bead aggregation assays, we show that copper promotes cis- as well as trans-directed dimerization of APLP1 and APLP2, similar as reported previously for APP. Furthermore, we report a APP-specific zinc binding site with nanomolar affinity located in the E1 domain, whereas no binding of zinc to the individual subdomains GFLD or CuBD was detected. Zinc binding did not affect the cis- but trans-dimerization of APP and APLP1. Furthermore, zinc binding inhibited copper-induced trans-directed dimerization of APP. Together, we identified a high-affinity APP-specific zinc binding site in the E1 domain and revealed contrasting cis- and trans-directed dimerization properties of APP, APLP1, and APLP2 in dependence on zinc and copper ions. Consequently, changes in metal ion homeostasis, as reported in the context of synaptic activity and neurodegenerative diseases, appear as key modulators of homo- and heterotypic trans-cellular APP/APLPs complexes.
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http://dx.doi.org/10.1111/jnc.14716DOI Listing
December 2019

Therapist-Guided Tablet-Based Telerehabilitation for Patients With Aphasia: Proof-of-Concept and Usability Study.

JMIR Rehabil Assist Technol 2019 Apr 26;6(1):e13163. Epub 2019 Apr 26.

Gerontechnology & Rehabilitation Group, University of Bern, Bern, Switzerland.

Background: Aphasia is the loss or impairment of language functions and affects everyday social life. The disorder leads to the inability to understand and be understood in both written and verbal communication and affects the linguistic modalities of auditory comprehension, verbal expression, reading, and writing. Due to heterogeneity of the impairment, therapy must be adapted individually and dynamically to patient needs. An important factor for successful aphasia therapy is dose and intensity of therapy. Tablet computer-based apps are a promising treatment method that allows patients to train independently at home, is well accepted, and is known to be beneficial for patients. In addition, it has been shown to ease the burden of therapists.

Objective: The aim of this project was to develop an adaptive multimodal system that enables aphasic patients to train at home using language-related tasks autonomously, allows therapists to remotely assign individualized tasks in an easy and time-efficient manner, and tracks the patient's progress as well as creation of new individual exercises.

Methods: The system consists of two main parts: (1) the patient's interface, which allows the patient to exercise, and (2) the therapist's interface, which allows the therapist to assign new exercises to the patient and supervise the patient's progress. The pool of exercises is based on a hierarchical language structure. Using questionnaires, therapists and patients evaluated the system in terms of usability (ie, System Usability Scale) and motivation (ie, adapted Intrinsic Motivation Inventory).

Results: A total of 11 speech and language therapists (age: mean 28, SD 7 years) and 15 patients (age: mean 53, SD 10 years) diagnosed with aphasia participated in this study. Patients rated the Bern Aphasia App in terms of usability (scale 0-100) as excellent (score >70; Z=-1.90; P=.03) and therapists rated the app as good (score >85; Z=-1.75; P=.04). Furthermore, patients enjoyed (scale 0-6) solving the exercises (score>3; mean 3.5, SD 0.40; Z=-1.66; P=.049).

Conclusions: Based on the questionnaire scores, the system is well accepted and simple to use for patients and therapists. Furthermore, the new tablet computer-based app and the hierarchical language exercise structure allow patients with different types of aphasia to train with different doses and intensities independently at home. Thus, the novel system has potential for treatment of patients with aphasia as a supplement to face-to-face therapy.
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http://dx.doi.org/10.2196/13163DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6658255PMC
April 2019

Differential involvement of TAK1, RIPK1 and NF-κB signaling in Smac mimetic-induced cell death in breast cancer cells.

Biol Chem 2019 01;400(2):171-180

Institute for Experimental Cancer Research in Pediatrics, Goethe University, Komturstrasse 3a, D-60528 Frankfurt/Main, Germany.

Smac mimetics (SMs) are considered promising cancer therapeutics. However, the mechanisms responsible for mediating cell death by SMs are still only partly understood. Therefore, in this study, we investigated signaling pathways upon treatment with the bivalent SM BV6 using two SM-sensitive breast cancer cell lines as models. Interestingly, genetic silencing of transforming growth factor (TGF)β activated kinase (TAK)1, an upstream activator of the nuclear factor-kappaB (NF-κB) subunit RelA (p65), increased BV6-induced cell death only in EVSA-T cells, although it reduced BV6-mediated upregulation of tumor necrosis factor (TNF)α in both EVSA-T and MDA-MB-231 cells. By comparison, genetic silencing of p65, a key component of canonical NF-κB signaling, blocked BV6-induced cell death in MDA-MB-231 but not in EVSA-T cells. Similarly, knockdown of NF-κB-inducing kinase (NIK) rescued MDA-MB-231 cells from BV6-induced cell death, while it failed to do so in EVSA-T cells. Consistently, silencing of p65 or NIK reduced BV6-stimulated upregulation of TNFα in MDA-MB-231 cells. In conclusion, TAK1, receptor-interacting kinase 1 (RIPK1) as well as canonical and non-canonical NF-κB signaling are differentially involved in SM-induced cell death in breast cancer cells. These findings contribute to a better understanding of SM-induced signaling pathways.
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http://dx.doi.org/10.1515/hsz-2018-0324DOI Listing
January 2019

Effect of vitamin E supplementation in milk replacer and Shiga toxoid vaccination on serum α-tocopherol, performance, haematology and blood chemistry in male Holstein calves.

J Anim Physiol Anim Nutr (Berl) 2018 Oct 15;102(5):1167-1180. Epub 2018 Jun 15.

Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institut, Brunswick, Germany.

Vitamin E (vit E), an essential antioxidant for maintaining the stability of biological membranes and the function of the immune system, is considered to support adaptive immune responses and performance in cattle. The principal virulence factor of Shiga toxin (Stx)-producing Escherichia coli (STEC), the eponymous Stx, modulates cellular immune responses in cattle, the primary STEC reservoir. Active and passive immunization of calves with Shiga toxoids (rStx ) was recently shown to reduce the STEC shedding. Here, we examined the influence of vit E on calves' serum α-tocopherol, performance, haematology, blood chemistry and its interaction with rStx immunization. Data from calves having received passive (colostrum from immunized cows) and active (intramuscularly at 5th and 8th weeks of life) vaccination with rStx (n = 24) were compared to unvaccinated controls (n = 24; fed with low anti-Stx colostrum, placebo injected). For each vaccination group, data were analysed according to the level of vit E supplementation offered by milk replacer (188 IU all-rac-α-tocopheryl acetate daily [VitE ] vs. 354 IU [VitE ]). An increase by 79% in daily vit E supplementation led to slightly higher serum α-tocopherol level and earlier concentrate intake at the beginning of the experiment without significant differences in live weight gain, haematology, blood chemistry parameters and peripheral CD4 and CD8 T-cell subpopulations. rStx vaccination modulated the CD4 /CD8 ratio irrespective of vit E supplementation but decreased concentrate intake in VitE in a time-dependent manner. Results of our study indicate that an increase in daily vit E supplementation vastly fails to exert effects on laboratory parameters and growth performance. However, observed interactive effects of vit E supply and vaccination on the regulation of feed intake deserves further attention.
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http://dx.doi.org/10.1111/jpn.12926DOI Listing
October 2018

Bordetella pseudohinzii targets cilia and impairs tracheal cilia-driven transport in naturally acquired infection in mice.

Sci Rep 2018 04 9;8(1):5681. Epub 2018 Apr 9.

Institute of Anatomy and Cell Biology, German Center for Lung Research (DZL), Excellence Cluster Cardio-Pulmonary System (ECCPS), Justus-Liebig-University Giessen, Giessen, Germany.

Several species of the Gram-negative genus Bordetella are the cause of respiratory infections in mammals and birds, including whooping cough (pertussis) in humans. Very recently, a novel atypical species, Bordetella pseudohinzii, was isolated from laboratory mice. These mice presented no obvious clinical symptoms but elevated numbers of neutrophils in bronchoalveolar lavage fluid and inflammatory signs in histopathology. We noted that this species can occur at high prevalence in a mouse facility despite regular pathogen testing according to the FELASA-recommendations. Affected C57BL/6 J mice had, in addition to the reported pulmonary alterations, tracheal inflammation with reduced numbers of ciliated cells, slower ciliary beat frequency, and largely (>50%) compromised cilia-driven particle transport speed on the mucosal surface, a primary innate defence mechanism. In an in vitro-model, Bordetella pseudohinzii attached to respiratory kinocilia, impaired ciliary function within 4 h and caused epithelial damage within 24 h. Regular testing for this ciliotropic Bordetella species and excluding it from colonies that provide mice for lung research shall be recommended. On the other hand, controlled colonization and infection with Bordetella pseudohinzii may serve as an experimental model to investigate mechanisms of mucociliary clearance and microbial strategies to escape from this primary innate defence response.
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http://dx.doi.org/10.1038/s41598-018-23830-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5890243PMC
April 2018

Decreased STEC shedding by cattle following passive and active vaccination based on recombinant Escherichia coli Shiga toxoids.

Vet Res 2018 03 7;49(1):28. Epub 2018 Mar 7.

Friedrich-Loeffler-Institut (FLI)/Federal Research Institute for Animal Health, Institute of Molecular Pathogenesis, Jena, Germany.

The principal virulence factor of Shiga toxin (Stx)-producing Escherichia coli (STEC), the eponymous Stx, modulates cellular immune responses in cattle, the primary STEC reservoir. We examined whether immunization with genetically inactivated recombinant Shiga toxoids (rStx1/rStx2) influences STEC shedding in a calf cohort. A group of 24 calves was passively (colostrum from immunized cows) and actively (intra-muscularly at 5 and 8 week) vaccinated. Twenty-four calves served as unvaccinated controls (fed with low anti-Stx colostrum, placebo injected). Each group was divided according to the vitamin E concentration they received by milk replacer (moderate and high supplemented). The effective transfer of Stx-neutralizing antibodies from dams to calves via colostrum was confirmed by Vero cell assay. Serum antibody titers in calves differed significantly between the vaccinated and the control group until the 16 week of life. Using the expression of activation marker CD25 on CD4CD45RO cells and CD8αCD45RO cells as flow cytometry based read-out, cells from vaccinated animals responded more pronounced than those of control calves to lysates of STEC and E. coli strains isolated from the farm as well as to rStx2 in the 16 week. Summarized for the entire observation period, less fecal samples from vaccinated calves were stx and/or stx positive than samples from control animals when calves were fed a moderate amount of vitamin E. This study provides first evidence, that transfer to and induction in young calves of Stx-neutralizing antibodies by Shiga toxoid vaccination offers the opportunity to reduce the incidence of stx-positive fecal samples in a calf cohort.
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http://dx.doi.org/10.1186/s13567-018-0523-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5842637PMC
March 2018

Smac mimetic induces an early wave of gene expression via NF-κB and AP-1 and a second wave via TNFR1 signaling.

Cancer Lett 2018 05 5;421:170-185. Epub 2018 Feb 5.

Institute for Experimental Cancer Research in Pediatrics, Goethe-University, Frankfurt, Germany; German Cancer Consortium (DKTK), Partner Site Frankfurt, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany. Electronic address:

Smac (second mitochondria-derived activator of caspases) mimetics are considered as promising cancer therapeutics, but little is yet known about how they alter gene expression. In this study, we used an unbiased genome-wide expression array to investigate gene regulation induced by the Smac mimetic BV6 in breast cancer cell lines. Here, we discover that tumor necrosis factor (TNF)α/TNF receptor 1 (TNFR1) auto-/paracrine signaling regulates Smac mimetic-stimulated changes in gene expression in a time-dependent manner. TNFR1-independent and -dependent genes account for two subsequent waves of BV6-induced gene expression. While the first wave mostly comprises TNFR1-independent genes and involves nuclear factor-kappa B (NF-κB) and activator protein (AP)-1 transcription factors, the second wave largely depends on TNFR1 signaling. Interestingly, disrupting auto-/paracrine TNFα/TNFR1 signaling by knockdown of TNFR1 strongly attenuates the BV6-induced second wave of gene expression and upregulation of many pathways, including NF-κB, apoptosis and immune signaling, while activation of mitogen-activated protein kinase (MAPK) signaling occurs also in TNFR1 knockdown cells. Thus, BV6 alters gene expression in a time- as well as TNFR1-dependent manner.
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http://dx.doi.org/10.1016/j.canlet.2018.01.082DOI Listing
May 2018

Neuroplastin and Basigin Are Essential Auxiliary Subunits of Plasma Membrane Ca-ATPases and Key Regulators of Ca Clearance.

Neuron 2017 Nov 19;96(4):827-838.e9. Epub 2017 Oct 19.

Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany; Logopharm GmbH, Schlossstrasse 14, 79232 March-Buchheim, Germany; Center for Biological Signaling Studies (BIOSS), Schänzlestrasse 18, 79104 Freiburg, Germany. Electronic address:

Plasma membrane Ca-ATPases (PMCAs), a family of P-type ATPases, extrude Ca ions from the cytosol to the extracellular space and are considered to be key regulators of Ca signaling. Here we show by functional proteomics that native PMCAs are heteromeric complexes that are assembled from two pore-forming PMCA1-4 subunits and two of the single-span membrane proteins, either neuroplastin or basigin. Contribution of the two Ig domain-containing proteins varies among different types of cells and along postnatal development. Complex formation of neuroplastin or basigin with PMCAs1-4 occurs in the endoplasmic reticulum and is obligatory for stability of the PMCA proteins and for delivery of PMCA complexes to the surface membrane. Knockout and (over)-expression of both neuroplastin and basigin profoundly affect the time course of PMCA-mediated Ca transport, as well as submembraneous Ca concentrations under steady-state conditions. Together, these results establish neuroplastin and basigin as obligatory auxiliary subunits of native PMCAs and key regulators of intracellular Ca concentration.
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http://dx.doi.org/10.1016/j.neuron.2017.09.038DOI Listing
November 2017

Very Rare Amelanotic Lentigo Maligna Melanoma with Skull Roof Invasion.

Open Access Maced J Med Sci 2017 Jul 19;5(4):458-461. Epub 2017 Jul 19.

Department of Anesthesiology & Intensive Care Medicine, Emergency Medicine & Pain Management, Hospital Dresden-Friedrichstadt, Academic Teaching Hospital of the Technical University of Dresden, Friedrichstrasse 41, 01067, Dresden, Germany.

Background: Lentigo malignant melanoma is a melanoma subtype of chronic sun-damaged skin in elderly Caucasians. Amelanotic variants of lentigo malignant are extremely rare.

Case Presentation: This is a case report of an 80-year-old male patient who presented with a non-pigmented exophytic tumour of his bald head. After complete surgical excision under the suspicion of squamous cell carcinoma, three-dimensional histologic examination confirmed an amelanotic lentigo malignant melanoma with a tumour thickness of 1.76 mm, resected R0. Five years later he developed the first relapse, the other year a satellite metastasis was surgically removed. One year later, this patient had developed a large relapsing lentigo malignant melanoma with skull roof invasion. There was no evidence of distant metastatic spread. Amelanotic lentigo malignant melanoma is a very rare tumour.

Conclusions: Serial excision or slow Mohs and Mohs micrographic surgery are the treatments of choice especially in the head and neck area. These tumours may be locally very aggressive as it is shown by skull invasion in the present case.
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http://dx.doi.org/10.3889/oamjms.2017.113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5535657PMC
July 2017

LRP1 Modulates APP Intraneuronal Transport and Processing in Its Monomeric and Dimeric State.

Front Mol Neurosci 2017 27;10:118. Epub 2017 Apr 27.

Division of Human Biology and Human Genetics, Technical University of KaiserslauternKaiserslautern, Germany.

The low-density lipoprotein receptor-related protein 1, LRP1, interacts with APP and affects its processing. This is assumed to be mostly caused by the impact of LRP1 on APP endocytosis. More recently, also an interaction of APP and LRP1 early in the secretory pathway was reported whereat retention of LRP1 in the ER leads to decreased APP cell surface levels and in turn, to reduced Aβ secretion. Here, we extended the biochemical and immunocytochemical analyses by showing via live cell imaging analyses in primary neurons that LRP1 and APP are transported only partly in common (one third) but to a higher degree in distinct fast axonal transport vesicles. Interestingly, co-expression of LRP1 and APP caused a change of APP transport velocities, indicating that LRP1 recruits APP to a specific type of fast axonal transport vesicles. In contrast lowered levels of LRP1 facilitated APP transport. We further show that monomeric and dimeric APP exhibit similar transport characteristics and that both are affected by LRP1 in a similar way, by slowing down APP anterograde transport and increasing its endocytosis rate. In line with this, a knockout of LRP1 in CHO cells and in primary neurons caused an increase of monomeric and dimeric APP surface localization and in turn accelerated shedding by meprin β and ADAM10. Notably, a choroid plexus specific LRP1 knockout caused a much higher secretion of sAPP dimers into the cerebrospinal fluid compared to sAPP monomers. Together, our data show that LRP1 functions as a sorting receptor for APP, regulating its cell surface localization and thereby its processing by ADAM10 and meprin β, with the latter exhibiting a preference for APP in its dimeric state.
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http://dx.doi.org/10.3389/fnmol.2017.00118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5406469PMC
April 2017

Metabolite Profile and Antiproliferative Effects in HaCaT Cells of a Salix reticulata Extract.

Planta Med 2017 Oct 27;83(14-15):1149-1158. Epub 2017 Apr 27.

Division of Pharmaceutical Biology, University of Basel, Switzerland.

Phenolic constituents of (Salicaceae) and antiproliferative activity of an extract and individual compounds were investigated in immortalized human non-tumorigenic keratinocytes (HaCaT). A MeOH extract from aerial parts afforded several flavonoids, including luteolin and apigenin glycosides (- and ) and catechin (), two procyanidin fractions, and the phenolic glucosides picein (), triandrin (), and salicortin (). In an adenosine triphosphate assay, the MeOH extract reduced cell viability by approximately 60 % at a concentration of 100 µg/mL. Cell proliferation was assessed with a BrdU incorporation ELISA assay. The extract inhibited proliferation of HaCaT cells in a concentration-dependent manner, with approximately 50 % inhibition at 100 µg/mL. In time-lapse assays, the extract showed distinct inhibitory effects on cell migration at concentrations of 12.5, 25, and 50 µg/mL. The activity of selected constituents was also determined. Luteolin-7-O--glucuronide () significantly inhibited cell proliferation at concentrations of 10 and 50 µM. In contrast, luteolin-7-O--glucopyranoside () and a procyanidin fraction (P1) had only weak effects, while picein () and salicortin () did not affect cell proliferation. Luteolin-7-O--glucuronide (10 µM) and, to a lesser extent, the procyanidin fraction (10 µg/mL) also inhibited cell migration.
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http://dx.doi.org/10.1055/s-0043-109098DOI Listing
October 2017

A Cell Culture System to Investigate the Presynaptic Control of Subsynaptic Membrane Differentiation at the Neuromuscular Junction.

Methods Mol Biol 2017 ;1538:3-11

Department of Biomedicine, University of Basel, Klingelbergstrasse 50, 4051, Basel, Switzerland.

For decades the neuromuscular junction (NMJ) has been a favorite preparation to investigate basic mechanisms of synaptic function and development. As its function is to transmit action potentials in a 1:1 ratio from motor neurons to muscle fibers, the NMJ shows little or no functional plasticity, a property that makes it poorly suited to investigate mechanisms of use-dependent adaptations of synaptic function, which are thought to underlie learning and memory formation in the brain. On the other hand, the NMJ is unique in that the differentiation of the subsynaptic membrane is regulated by one major factor secreted from motor neurons, agrin. As a consequence, myotubes grown on a laminin substrate that is focally impregnated with recombinant neural agrin closely resemble the situation in vivo, where agrin secreted from motor neurons binds to the basal lamina of the NMJ's synaptic cleft to induce and maintain the subsynaptic muscle membrane. We provide here a detailed protocol through which acetylcholine receptor clusters are induced in cultured myotubes contacting laminin-attached agrin, enabling molecular, biochemical and cell biological analyses including high resolution microscopy in 4D. This preparation is ideally suited to investigate the mechanisms involved in the assembly of the postsynaptic muscle membrane, providing distinct advantages over inducing AChR clusters using soluble agrin.
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http://dx.doi.org/10.1007/978-1-4939-6688-2_1DOI Listing
January 2018

GTSE1 tunes microtubule stability for chromosome alignment and segregation by inhibiting the microtubule depolymerase MCAK.

J Cell Biol 2016 Dec 23;215(5):631-647. Epub 2016 Nov 23.

Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany

The dynamic regulation of microtubules (MTs) during mitosis is critical for accurate chromosome segregation and genome stability. Cancer cell lines with hyperstabilized kinetochore MTs have increased segregation errors and elevated chromosomal instability (CIN), but the genetic defects responsible remain largely unknown. The MT depolymerase MCAK (mitotic centromere-associated kinesin) can influence CIN through its impact on MT stability, but how its potent activity is controlled in cells remains unclear. In this study, we show that GTSE1, a protein found overexpressed in aneuploid cancer cell lines and tumors, regulates MT stability during mitosis by inhibiting MCAK MT depolymerase activity. Cells lacking GTSE1 have defects in chromosome alignment and spindle positioning as a result of MT instability caused by excess MCAK activity. Reducing GTSE1 levels in CIN cancer cell lines reduces chromosome missegregation defects, whereas artificially inducing GTSE1 levels in chromosomally stable cells elevates chromosome missegregation and CIN. Thus, GTSE1 inhibition of MCAK activity regulates the balance of MT stability that determines the fidelity of chromosome alignment, segregation, and chromosomal stability.
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http://dx.doi.org/10.1083/jcb.201606081DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5147003PMC
December 2016

Conventional kinesin: Biochemical heterogeneity and functional implications in health and disease.

Brain Res Bull 2016 09 20;126(Pt 3):347-353. Epub 2016 Jun 20.

Division of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany. Electronic address:

Intracellular trafficking events powered by microtubule-based molecular motors facilitate the targeted delivery of selected molecular components to specific neuronal subdomains. Within this context, we provide a brief review of mechanisms underlying the execution of axonal transport (AT) by conventional kinesin, the most abundant kinesin-related motor protein in the mature nervous system. We emphasize the biochemical heterogeneity of this multi-subunit motor protein, further discussing its significance in light of recent discoveries revealing its regulation by various protein kinases. In addition, we raise issues relevant to the mode of conventional kinesin attachment to cargoes and examine recent evidence linking alterations in conventional kinesin phosphorylation to the pathogenesis of adult-onset neurodegenerative diseases.
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http://dx.doi.org/10.1016/j.brainresbull.2016.06.009DOI Listing
September 2016

Dual and Opposing Roles of Xanthine Dehydrogenase in Defense-Associated Reactive Oxygen Species Metabolism in Arabidopsis.

Plant Cell 2016 05 5;28(5):1108-26. Epub 2016 May 5.

Institute of Biosciences and Biotechnology Research and Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland 20850

While plants produce reactive oxygen species (ROS) for stress signaling and pathogen defense, they need to remove excessive ROS induced during stress responses in order to minimize oxidative damage. How can plants fine-tune this balance and meet such conflicting needs? Here, we show that XANTHINE DEHYDROGENASE1 (XDH1) in Arabidopsis thaliana appears to play spatially opposite roles to serve this purpose. Through a large-scale genetic screen, we identified three missense mutations in XDH1 that impair XDH1's enzymatic functions and consequently affect the powdery mildew resistance mediated by RESISTANCE TO POWDERY MILDEW8 (RPW8) in epidermal cells and formation of xanthine-enriched autofluorescent objects in mesophyll cells. Further analyses revealed that in leaf epidermal cells, XDH1 likely functions as an oxidase, along with the NADPH oxidases RbohD and RbohF, to generate superoxide, which is dismutated into H2O2 The resulting enrichment of H2O2 in the fungal haustorial complex within infected epidermal cells helps to constrain the haustorium, thereby contributing to RPW8-dependent and RPW8-independent powdery mildew resistance. By contrast, in leaf mesophyll cells, XDH1 carries out xanthine dehydrogenase activity to produce uric acid in local and systemic tissues to scavenge H2O2 from stressed chloroplasts, thereby protecting plants from stress-induced oxidative damage. Thus, XDH1 plays spatially specified dual and opposing roles in modulation of ROS metabolism during defense responses in Arabidopsis.
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http://dx.doi.org/10.1105/tpc.15.00880DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4904670PMC
May 2016

Fish protein increases circulating levels of trimethylamine-N-oxide and accelerates aortic lesion formation in apoE null mice.

Mol Nutr Food Res 2016 Feb 26;60(2):358-68. Epub 2015 Oct 26.

Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany.

Scope: The protective effect of fish consumption on the cardiovascular system has primarily been ascribed to n-3 fatty acids, but data investigating the vascular effects of fish protein consumption are scarce. This study aimed to investigate the vascular impact of fish protein in a mouse model of atherosclerosis.

Methods And Results: Male apoE null mice were fed a Western diet containing 20% fish (turbot) protein, casein, or soy protein, for 16 wk. Morphometric analysis of the aorta revealed that the atherosclerotic plaque area of fish protein fed mice was twofold larger than that in casein- or soy protein-fed mice. The percentage area of calcification deposits in plaques of fish protein fed mice was higher (7.57%) than that in casein-fed (2.86%) or soy protein-fed (3.46%) mice, and fish protein fed mice exhibited higher plaque expression of CD68, CD36, and IL-6 than the other two groups. Fish protein intake was accompanied by increased serum concentrations of trimethylamine-N-oxide (7.03 ± 2.83 μmol/L), as compared with casein (0.92 ± 0.46 μmol/L) and soy protein (1.32 ± 0.54 μmol/L) intake.

Conclusion: The present data indicate adverse effects of fish protein on the vascular system, which could be attributable to the high serum trimethylamine-N-oxide concentrations in these mice.
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http://dx.doi.org/10.1002/mnfr.201500537DOI Listing
February 2016

SorCS1 variants and amyloid precursor protein (APP) are co-transported in neurons but only SorCS1c modulates anterograde APP transport.

J Neurochem 2015 Oct 26;135(1):60-75. Epub 2015 Aug 26.

Division of Human Biology and Human Genetics, University of Kaiserslautern, Kaiserslautern, Germany.

Processing of amyloid precursor protein (APP) into amyloid-β peptide (Aβ) is crucial for the development of Alzheimer's disease (AD). Because this processing is highly dependent on its intracellular itinerary, altered subcellular targeting of APP is thought to directly affect the degree to which Aβ is generated. The sorting receptor SorCS1 has been genetically linked to AD, but the underlying molecular mechanisms are poorly understood. We analyze two SorCS1 variants; one, SorCS1c, conveys internalization of surface-bound ligands whereas the other, SorCS1b, does not. In agreement with previous studies, we demonstrate co-immunoprecipitation and co-localization of both SorCS1 variants with APP. Our results suggest that SorCS1c and APP are internalized independently, although they mostly share a common post-endocytic pathway. We introduce functional Venus-tagged constructs to study SorCS1b and SorCS1c in living cells. Both variants are transported by fast anterograde axonal transport machinery and about 30% of anterograde APP-positive transport vesicles contain SorCS1. Co-expression of SorCS1b caused no change of APP transport kinetics, but SorCS1c reduced the anterograde transport rate of APP and increased the number of APP-positive stationary vesicles. These data suggest that SorCS1 and APP share trafficking pathways and that SorCS1c can retain APP from insertion into anterograde transport vesicles. Altered APP trafficking is thought to modulate its processing. SorCS1 has been suggested to function in APP trafficking. We analyzed if the two SorCS1 variants, SorCS1b and SorCS1c, tie APP to the cell surface or modify its internalization and intracellular targeting. We observed co-localization and vesicular co-transport of APP and SorCS1, but independent internalization and sorting through a common post-endocytic pathway. Co-expression of one variant, SorCS1c, reduced anterograde APP transport. These data demonstrate that SorCS1 and APP share trafficking pathways and that SorCS1c can retain APP from insertion into anterograde transport vesicles.
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http://dx.doi.org/10.1111/jnc.13221DOI Listing
October 2015

The Antiatherogenic Effect of Fish Oil in Male Mice Is Associated with a Diminished Release of Endothelial ADAM17 and ADAM10 Substrates.

J Nutr 2015 Jun 29;145(6):1218-26. Epub 2015 Apr 29.

Department of Dermatology,

Background: Growing evidence suggests that disintegrin and metalloprotease (ADAM) 17 (ADAM17) and ADAM10 contribute to the pathogenesis of vascular diseases. ADAM17 promotes inflammatory processes by liberating tumor necrosis factor α, interleukin 6 receptor (IL-6R), and tumor necrosis factor receptor 1 (TNFR1). ADAM17 and ADAM10 modulate vascular permeability by cleaving endothelial adhesion molecules such as junctional adhesion molecule A (JAM-A) and vascular endothelial cadherin (VE-cadherin), respectively.

Objective: This study was designed to investigate whether a link might exist between the protective effects of fish oil (FO) supplementation against atherosclerosis and ADAM function.

Methods: Male LDL receptor knockout (LDLR(-/-)) mice and male wild-type (WT) mice were fed a Western diet (200 g/kg fat, 1.5 g/kg cholesterol) containing either 20% lard (LDLR(-/-)-lard and WT-lard groups) or 10% lard combined with 10% FO (LDLR(-/-)-FO and WT-FO groups) for 12 wk. Atherosclerotic lesion development and fatty acid composition of liver microsomes were evaluated. ADAM10 and ADAM17 expression was determined by quantitative real-time polymerase chain reaction and immunoblot analyses. Concentrations of soluble ADAM substrates in plasma and liver extracts were measured by ELISA.

Results: Diets supplemented with FO markedly reduced development of early atherosclerotic lesions in LDLR(-/-) mice (LDLR(-/-)-lard group vs. LDLR(-/-)-FO group mean ± SD: 29.6 ± 6.1% vs. 22.5 ± 4.2%, P < 0.05). This was not accompanied by changes in expression of ADAM17 or ADAM10 in the aorta or liver. No dietary effects on circulating TNFR1 (LDLR(-/-)-lard group vs. LDLR(-/-)-FO group mean ± SD: 1.22 ± 0.23 vs. 1.39 ± 0.28, P > 0.2) or IL-6R (1.06 ± 0.12 vs. 0.98 ± 0.09 fold of WT-lard group, P > 0.1), classical substrates of ADAM17 on macrophages, and neutrophil granulocytes were observed. However, a reduction in atherosclerotic lesions in the LDLR(-/-)-FO group was accompanied by a significant reduction in the circulating endothelial cell adhesion molecules JAM-A (LDLR(-/-)-lard group vs. LDLR(-/-)-FO group mean ± SD: 1.42 ± 0.20 vs. 0.95 ± 0.56 fold of WT-lard group, P < 0.05), intercellular adhesion molecule 1 (1.15 ± 0.14 vs. 0.88 ± 0.17 fold of WT-lard group, P < 0.05), and VE-cadherin (0.88 ± 0.12 vs. 0.72 ± 0.15 fold of WT-lard group, P < 0.05), reflecting reduced ADAM activity in endothelial cells.

Conclusion: FO exerted an antiatherogenic effect on male LDLR(-/-) mice that was accompanied by a reduced release of ADAM17 and ADAM10 substrates from endothelial cells. It is suggested that FO-decreased ADAM activity contributes to improved endothelial barrier function and thus counteracts intimal lipoprotein insudation and macrophage accumulation.
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http://dx.doi.org/10.3945/jn.115.211375DOI Listing
June 2015

Amyloid precursor protein dimerization and synaptogenic function depend on copper binding to the growth factor-like domain.

J Neurosci 2014 Aug;34(33):11159-72

Division of Human Biology and Human Genetics,

Accumulating evidence suggests that the copper-binding amyloid precursor protein (APP) has an essential synaptic function. APP synaptogenic function depends on trans-directed dimerization of the extracellular E1 domain encompassing a growth factor-like domain (GFLD) and a copper-binding domain (CuBD). Here we report the 1.75 Å crystal structure of the GFLD in complex with a copper ion bound with high affinity to an extended hairpin loop at the dimerization interface. In coimmunoprecipitation assays copper binding promotes APP interaction, whereas mutations in the copper-binding sites of either the GFLD or CuBD result in a drastic reduction in APP cis-orientated dimerization. We show that copper is essential and sufficient to induce trans-directed dimerization of purified APP. Furthermore, a mixed culture assay of primary neurons with HEK293 cells expressing different APP mutants revealed that APP potently promotes synaptogenesis depending on copper binding to the GFLD. Together, these findings demonstrate that copper binding to the GFLD of APP is required for APP cis-/trans-directed dimerization and APP synaptogenic function. Thus, neuronal activity or disease-associated changes in copper homeostasis likely go along with altered APP synaptic function.
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http://dx.doi.org/10.1523/JNEUROSCI.0180-14.2014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6705248PMC
August 2014