Publications by authors named "Sebastian Müller"

157 Publications

Important role of Nfkb2 in the Kras-driven carcinogenesis in the pancreas.

Pancreatology 2021 Mar 26. Epub 2021 Mar 26.

Medical Clinic and Polyclinic II, Klinikum rechts der Isar, Technical University Munich, 81675, München, Germany; German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), 69120, Heidelberg, Germany. Electronic address:

Background: Oncogenic Kras initiates and drives carcinogenesis in the pancreas by complex signaling networks, including activation of the NFκB pathway. Although recent evidence has shown that oncogenic gains in Nfκb2 collaborate with Kras in the carcinogenesis, no data at the level of genetics for the contribution of Nfκb2 is available so far.

Methods: We used Nfkb2 knock-out mice to decipher the role of the gene in Kras-driven carcinogenesis in vivo.

Results: We show that the Nfkb2 gene is needed for cancer initiation and progression in Kras-driven models and this requirement of Nfkb2 is mechanistically connected to proliferative pathways. In contrast, Nfκb2 is dispensable in aggressive pancreatic ductal adenocarcinoma (PDAC) models relying on the simultaneous expression of the Kras oncogene and the mutated tumor suppressor p53.

Conclusions: Our data add to the understanding of context-dependent requirements of oncogenic Kras signaling during pancreatic carcinogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.pan.2021.03.012DOI Listing
March 2021

Diagnostic value of diffusion-weighted STEAM-MRI in ischemic stroke.

Eur J Radiol 2021 Mar 26;139:109677. Epub 2021 Mar 26.

Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.

Introduction: Diffusion-weighted imaging in stimulated echo acquisition mode (STEAM-DWI) is an interesting alternative with less susceptibility artifacts compared to the most commonly used diffusion-weighted echo-planar imaging (EPI-DWI). Sensitivity and specificity of a novel STEAM-DWI, described by Merrem et al. 2017 [1], were assessed in patients with ischemic stroke.

Methods: EPI- and STEAM-DWIs were performed in patients with suspected subacute stroke between 01 July 2019 and 30 June 2020 using 3-T MRI. Three neuroradiologists independently and separately rated STEAM-DWI images with respect to (i) signs of an acute/subacute stroke, (ii) the number, size and localization of infarctions and, (iii) the presence of artifacts.

Results: In 55 (23 right, 23 left, 9 both hemispheres) of 85 patients a subacute stroke was confirmed using EPI-DWI. The cerebral vascular territories were affected as follows: anterior cerebral artery 8 %, middle cerebral artery 48 %, posterior cerebral artery 27 %, brainstem 7 %, cerebellum 10 %. In 53 of 55 (96 %) cases the stroke was detected by usage of STEAM-DWI, in 35 of 37 patients microembolic events were noticed (95 %). Results showed a sensitivity and specificity of 100 % (70/70) for major infarcts (>9 mm² in-plane) and a sensitivity of up to 94 % (121/129) for detecting subacute microembolic lesions. No susceptibility artifacts were noticed in STEAM-DWI.

Conclusion: Compared to standard EPI-DWI, STEAM-DWI offers a more robust alternative for diagnosing subacute strokes in areas affected by susceptibility artifacts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejrad.2021.109677DOI Listing
March 2021

[Update on Shoulder Arthroplasty].

Ther Umsch 2020 ;77(10):505-510

Abteilung für Orthopädie und Traumatologie, Universität Basel.

Update on Shoulder Arthroplasty Shoulder arthroplasty is indicated for treatment of primary osteoarthritis, cuff tear athropathy, complex proximal humerus fractures, and posttraumatic situations. The rotator cuff plays an important role. In case of an intact rotator cuff, anatomical shoulder arthroplasty is preferred. Over the past decades, the number of hemi prostheses has declined in favor of total shoulder arthroplasties. Reverse shoulder arthroplasty is used for severe and irreparable rotator cuff tears, advanced cuff tear athropathy, and increasingly for complex proximal humerus fractures. Reverse shoulder arthroplasties account for almost 80 % of all shoulder prostheses. Modern implants allow conversion from an anatomic to a reverse situation if needed. Improved understanding of the pathology, new implant designs, and preoperative 3D planning have improved the overall outcome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1024/0040-5930/a001227DOI Listing
December 2020

A hyperelastic model for simulating cells in flow.

Biomech Model Mechanobiol 2021 Apr 20;20(2):509-520. Epub 2020 Nov 20.

Theoretical Physics VI, Biofluid Simulation and Modeling, University of Bayreuth, Universitätsstraße 30, Bayreuth, 95440, Germany.

In the emerging field of 3D bioprinting, cell damage due to large deformations is considered a main cause for cell death and loss of functionality inside the printed construct. Those deformations, in turn, strongly depend on the mechano-elastic response of the cell to the hydrodynamic stresses experienced during printing. In this work, we present a numerical model to simulate the deformation of biological cells in arbitrary three-dimensional flows. We consider cells as an elastic continuum according to the hyperelastic Mooney-Rivlin model. We then employ force calculations on a tetrahedralized volume mesh. To calibrate our model, we perform a series of FluidFM[Formula: see text] compression experiments with REF52 cells demonstrating that all three parameters of the Mooney-Rivlin model are required for a good description of the experimental data at very large deformations up to 80%. In addition, we validate the model by comparing to previous AFM experiments on bovine endothelial cells and artificial hydrogel particles. To investigate cell deformation in flow, we incorporate our model into Lattice Boltzmann simulations via an Immersed-Boundary algorithm. In linear shear flows, our model shows excellent agreement with analytical calculations and previous simulation data.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10237-020-01397-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7979664PMC
April 2021

The small RNA locus map for Chlamydomonas reinhardtii.

PLoS One 2020 19;15(11):e0242516. Epub 2020 Nov 19.

Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom.

Small (s)RNAs play crucial roles in the regulation of gene expression and genome stability across eukaryotes where they direct epigenetic modifications, post-transcriptional gene silencing, and defense against both endogenous and exogenous viruses. It is known that Chlamydomonas reinhardtii, a well-studied unicellular green algae species, possesses sRNA-based mechanisms that are distinct from those of land plants. However, definition of sRNA loci and further systematic classification is not yet available for this or any other algae. Here, using data-driven machine learning approaches including Multiple Correspondence Analysis (MCA) and clustering, we have generated a comprehensively annotated and classified sRNA locus map for C. reinhardtii. This map shows some common characteristics with higher plants and animals, but it also reveals distinct features. These results are consistent with the idea that there was diversification in sRNA mechanisms after the evolutionary divergence of algae from higher plant lineages.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0242516PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7676726PMC
January 2021

Thermodynamic and electrochemical study of tailor-made crown ethers for redox-switchable (pseudo)rotaxanes.

Beilstein J Org Chem 2020 20;16:2576-2588. Epub 2020 Oct 20.

Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 20, 14195 Berlin, Germany.

Crown ethers are common building blocks in supramolecular chemistry and are frequently applied as cation sensors or as subunits in synthetic molecular machines. Developing switchable and specifically designed crown ethers enables the implementation of function into molecular assemblies. Seven tailor-made redox-active crown ethers incorporating tetrathiafulvalene (TTF) or naphthalene diimide (NDI) as redox-switchable building blocks are described with regard to their potential to form redox-switchable rotaxanes. A combination of isothermal titration calorimetry and voltammetric techniques reveals correlations between the binding energies and redox-switching properties of the corresponding pseudorotaxanes with secondary ammonium ions. For two different weakly coordinating anions, a surprising relation between the enthalpic and entropic binding contributions of the pseudorotaxanes was discovered. These findings were applied to the synthesis of an NDI-[2]rotaxane, which retains similar spectroelectrochemical properties compared to the corresponding free macrocycle. The detailed understanding of the thermodynamic and electrochemical properties of the tailor-made crown ethers lays the foundation for the construction of new types of molecular redox switches with emergent properties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3762/bjoc.16.209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7590624PMC
October 2020

Clouds and Convective Self-Aggregation in a Multimodel Ensemble of Radiative-Convective Equilibrium Simulations.

J Adv Model Earth Syst 2020 Sep 18;12(9):e2020MS002138. Epub 2020 Sep 18.

NOAA/Geophysical Fluid Dynamics Laboratory Princeton NJ USA.

The Radiative-Convective Equilibrium Model Intercomparison Project (RCEMIP) is an intercomparison of multiple types of numerical models configured in radiative-convective equilibrium (RCE). RCE is an idealization of the tropical atmosphere that has long been used to study basic questions in climate science. Here, we employ RCE to investigate the role that clouds and convective activity play in determining cloud feedbacks, climate sensitivity, the state of convective aggregation, and the equilibrium climate. RCEMIP is unique among intercomparisons in its inclusion of a wide range of model types, including atmospheric general circulation models (GCMs), single column models (SCMs), cloud-resolving models (CRMs), large eddy simulations (LES), and global cloud-resolving models (GCRMs). The first results are presented from the RCEMIP ensemble of more than 30 models. While there are large differences across the RCEMIP ensemble in the representation of mean profiles of temperature, humidity, and cloudiness, in a majority of models anvil clouds rise, warm, and decrease in area coverage in response to an increase in sea surface temperature (SST). Nearly all models exhibit self-aggregation in large domains and agree that self-aggregation acts to dry and warm the troposphere, reduce high cloudiness, and increase cooling to space. The degree of self-aggregation exhibits no clear tendency with warming. There is a wide range of climate sensitivities, but models with parameterized convection tend to have lower climate sensitivities than models with explicit convection. In models with parameterized convection, aggregated simulations have lower climate sensitivities than unaggregated simulations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1029/2020MS002138DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7539986PMC
September 2020

Synergistic targeting and resistance to PARP inhibition in DNA damage repair-deficient pancreatic cancer.

Gut 2021 Apr 1;70(4):743-760. Epub 2020 Sep 1.

Department of Internal Medicine I, Ulm University Hospital, Ulm, Germany

Objective: (ATM) is the most frequently mutated DNA damage response gene, involved in homologous recombination (HR), in pancreatic ductal adenocarcinoma (PDAC).

Design: Combinational synergy screening was performed to endeavour a genotype-tailored targeted therapy.

Results: Synergy was found on inhibition of PARP, ATR and DNA-PKcs (PAD) leading to synthetic lethality in ATM-deficient murine and human PDAC. Mechanistically, PAD-induced PARP trapping, replication fork stalling and mitosis defects leading to P53-mediated apoptosis. Most importantly, chemical inhibition of ATM sensitises human PDAC cells toward PAD with long-term tumour control in vivo. Finally, we anticipated and elucidated PARP inhibitor resistance within the ATM-null background via whole exome sequencing. Arising cells were aneuploid, underwent epithelial-mesenchymal-transition and acquired multidrug resistance (MDR) due to upregulation of drug transporters and a bypass within the DNA repair machinery. These functional observations were mirrored in copy number variations affecting a region on chromosome 5 comprising several of the upregulated MDR genes. Using these findings, we ultimately propose alternative strategies to overcome the resistance.

Conclusion: Analysis of the molecular susceptibilities triggered by ATM deficiency in PDAC allow elaboration of an efficient mutation-specific combinational therapeutic approach that can be also implemented in a genotype-independent manner by ATM inhibition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/gutjnl-2019-319970DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7948173PMC
April 2021

Alcohol Use and Gastrointestinal Disease.

Visc Med 2020 Jun 10;36(3):227-230. Epub 2020 Jun 10.

Klinik für Innere Medizin I, Universitätsklinikum Ulm, Ulm, Germany.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1159/000507743DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7383257PMC
June 2020

CD44 regulates epigenetic plasticity by mediating iron endocytosis.

Nat Chem 2020 10 3;12(10):929-938. Epub 2020 Aug 3.

Institut Curie, Paris, France.

CD44 is a transmembrane glycoprotein linked to various biological processes reliant on epigenetic plasticity, which include development, inflammation, immune responses, wound healing and cancer progression. Although it is often referred to as a cell surface marker, the functional regulatory roles of CD44 remain elusive. Here we report the discovery that CD44 mediates the endocytosis of iron-bound hyaluronates in tumorigenic cell lines, primary cancer cells and tumours. This glycan-mediated iron endocytosis mechanism is enhanced during epithelial-mesenchymal transitions, in which iron operates as a metal catalyst to demethylate repressive histone marks that govern the expression of mesenchymal genes. CD44 itself is transcriptionally regulated by nuclear iron through a positive feedback loop, which is in contrast to the negative regulation of the transferrin receptor by excess iron. Finally, we show that epigenetic plasticity can be altered by interfering with iron homeostasis using small molecules. This study reveals an alternative iron-uptake mechanism that prevails in the mesenchymal state of cells, which illuminates a central role of iron as a rate-limiting regulator of epigenetic plasticity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41557-020-0513-5DOI Listing
October 2020

Flow and hydrodynamic shear stress inside a printing needle during biofabrication.

PLoS One 2020 24;15(7):e0236371. Epub 2020 Jul 24.

Biofluid Simulation and Modeling, Universität Bayreuth, Bayreuth, Germany.

We present a simple but accurate algorithm to calculate the flow and shear rate profile of shear thinning fluids, as typically used in biofabrication applications, with an arbitrary viscosity-shear rate relationship in a cylindrical nozzle. By interpolating the viscosity with a set of power-law functions, we obtain a mathematically exact piecewise solution to the incompressible Navier-Stokes equation. The algorithm is validated with known solutions for a simplified Carreau-Yasuda fluid, full numerical simulations for a realistic chitosan hydrogel as well as experimental velocity profiles of alginate and chitosan solutions in a microfluidic channel. We implement the algorithm in an easy-to-use Python tool, included as Supplementary Material, to calculate the velocity and shear rate profile during the printing process, depending on the shear thinning behavior of the bioink and printing parameters such as pressure and nozzle size. We confirm that the shear stress varies in an exactly linear fashion, starting from zero at the nozzle center to the maximum shear stress at the wall, independent of the shear thinning properties of the bioink. Finally, we demonstrate how our method can be inverted to obtain rheological bioink parameters in-situ directly before or even during printing from experimentally measured flow rate versus pressure data.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0236371PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7380612PMC
September 2020

[Informed Employees - Informed Consent as Ethical Guidance for Behavioural Prevention in the Corporate Context].

Gesundheitswesen 2020 Jul 21. Epub 2020 Jul 21.

Fakultät für Medizin, Institut für Geschichte und Ethik der Medizin, Technische Universität München, München.

Background And Method: People have a right to physical and mental integrity in all spheres of life. They also have the right to autonomous actions and informed decisions regarding their health. To ensure this, informed consent has been the ethico-legal gold standard in medicine for some years now. The registration for measures of behavioural prevention, in contrast, is mainly conducted through forms focussing on data protection, with little attention to full informed consent of future participants. In this article, we discuss the ethical challenges that arise when employees consent to health-promoting measures. We then examine whether the instrument of informed consent can be translated to the context of behavioural prevention.

Results: Informed consent can be transferred to the corporate context in an altered version. Of particular importance is not only the handling of health-related data, but also the appropriate disclosure of all essential information as well as voluntary participation.

Conclusions: The adjusted version of informed consent in behavioural prevention ought to be developed further, resulting in a matrix of criteria that define conditions under which the informed consent can be applied to single measures of behavioural prevention.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1055/a-1205-0779DOI Listing
July 2020

Differentiation of arterial and venous neurovascular conflicts estimates the clinical outcome after microvascular decompression in trigeminal neuralgia.

BMC Neurol 2020 Jul 14;20(1):279. Epub 2020 Jul 14.

Departments of Neurosurgery, Georg-August-University Goettingen, Robert-Koch-Str. 40, 37075, Goettingen, Germany.

Background: Balanced Steady State Free Precession (b-SSFP) sequences and the newly developed Fast-Spin-Echo (FSE)-sequences enable an optimized visualization of neurovascular compression (NVC) in patients with trigeminal neuralgia (TN). Arterial conflicts are mostly associated with a favorable outcome of microvascular decompression (MVD) compared to venous conflicts. An additional Time-of-Flight (TOF) angiography provides the differentiation between offending arteries and veins and a precise counselling of the patient concerning postoperative pain relief. The goal of this study was to analyze the reliability and impact of the combination of highly-resoluted MRI techniques on the correct prediction of the vessel type and the estimation of postoperative outcome of microvascular decompression (MVD).

Methods: In total, 48 patients (m/f: 32/16) underwent MVD for TN. All the preoperative imaging data (T2: b-SFFP and FSE, MRA: TOF) were compared to the intraoperative microsurgical findings during MVD. b-SFFP was available in 14 patients, FSE in 34 patients and an additional TOF sequence was available in 38 patients (9 times in combination with b-SSFP, 29 times in combination with FSE). The patients were categorized into four subgroups: 1) NVC negative, 2) venous NVC, 3) arterial NVC, 4) combined arterial and venous NVC. The preoperative MRI findings were compared to the intraoperative morphological findings. Postoperative pain relief was quantified by the Barrow Neurological Institute pain score.

Results: Twenty-five purely arterial NVC, 9 purely venous NVC and 5 combined arterial and venous NVC were detected by MRI. In 9 cases NVC was absent on MRI. Overall, the MRI findings correctly predicted the intraoperative findings in 91.7% of the 48 patients. The percentage of correct prediction increased from 80 to 94.7%, when TOF angiography was adjoined.

Conclusion: The visualization of the trigeminal nerve using sequences such as b-SSFP or FSE in combination with TOF angiography enables an optimized delineation of arterial and venous neurovascular conflicts and may allow a more reliable differentiation between veins and arteries, resulting in superior prediction of postoperative pain relief compared to T2 imaging data alone.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12883-020-01860-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7359280PMC
July 2020

ESRRG and PERM1 Govern Mitochondrial Conversion in Brite/Beige Adipocyte Formation.

Front Endocrinol (Lausanne) 2020 12;11:387. Epub 2020 Jun 12.

Institute of Food, Nutrition and Health, Department of Health Sciences and Technology (D-HEST), ETH Zürich, Zurich, Switzerland.

When exposed to cold temperatures, mice increase their thermogenic capacity by an expansion of brown adipose tissue mass and the formation of brite/beige adipocytes in white adipose tissue depots. However, the process of the transcriptional changes underlying the conversion of a phenotypic white to brite/beige adipocytes is only poorly understood. By analyzing transcriptome profiles of inguinal adipocytes during cold exposure and in mouse models with a different propensity to form brite/beige adipocytes, we identified ESRRG and PERM1 as modulators of this process. The production of heat by mitochondrial uncoupled respiration is a key feature of brite/beige compared to white adipocytes and we show here that both candidates are involved in PGC1α transcriptional network to positively regulate mitochondrial capacity. Moreover, we show that an increased expression of ESRRG or PERM1 supports the formation of brown or brite/beige adipocytes and . These results reveal that ESRRG and PERM1 are early induced in and important regulators of brite/beige adipocyte formation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fendo.2020.00387DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7304443PMC
June 2020

ogs5py: A Python-API for the OpenGeoSys 5 Scientific Modeling Package.

Ground Water 2021 Jan 16;59(1):117-122. Epub 2020 Jun 16.

Department of Earth Sciences, Utrecht University, Princetonlaan 8a, 3584CB, Utrecht, The Netherlands.

High-performance numerical codes are an indispensable tool for hydrogeologists when modeling subsurface flow and transport systems. But as they are written in compiled languages, like C/C++ or Fortran, established software packages are rarely user-friendly, limiting a wider adoption of such tools. OpenGeoSys (OGS), an open-source, finite-element solver for thermo-hydro-mechanical-chemical processes in porous and fractured media, is no exception. Graphical user interfaces may increase usability, but do so at a dramatic reduction of flexibility and are difficult or impossible to integrate into a larger workflow. Python offers an optimal trade-off between these goals by providing a highly flexible, yet comparatively user-friendly environment for software applications. Hence, we introduce ogs5py, a Python-API for the OpenGeoSys 5 scientific modeling package. It provides a fully Python-based representation of an OGS project, a large array of convenience functions for users to interact with OGS and connects OGS to the scientific and computational environment of Python.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/gwat.13017DOI Listing
January 2021

Viral Fitness Determines the Magnitude of Transcriptomic and Epigenomic Reprograming of Defense Responses in Plants.

Mol Biol Evol 2020 07;37(7):1866-1881

Instituto de Biología Integrativa de Sistemas (I2SysBio), Consejo Superior de Investigaciones Científicas (CSIC)-Universitat de València, Paterna, Valencia, Spain.

Although epigenetic factors may influence the expression of defense genes in plants, their role in antiviral responses and the impact of viral adaptation and evolution in shaping these interactions are still poorly explored. We used two isolates of turnip mosaic potyvirus with varying degrees of adaptation to Arabidopsis thaliana to address these issues. One of the isolates was experimentally evolved in the plant and presented increased load and virulence relative to the ancestral isolate. The magnitude of the transcriptomic responses was larger for the evolved isolate and indicated a role of innate immunity systems triggered by molecular patterns and effectors in the infection process. Several transposable elements located in different chromatin contexts and epigenetic-related genes were also affected. Correspondingly, mutant plants having loss or gain of repressive marks were, respectively, more tolerant and susceptible to turnip mosaic potyvirus, with a more efficient response against the ancestral isolate. In wild-type plants, both isolates induced similar levels of cytosine methylation changes, including in and around transposable elements and stress-related genes. Results collectively suggested that apart from RNA silencing and basal immunity systems, DNA methylation and histone modification pathways may also be required for mounting proper antiviral defenses and that the effectiveness of this type of regulation strongly depends on the degree of viral adaptation to the host.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/molbev/msaa091DOI Listing
July 2020

Novel routes towards bioplastics from plants: elucidation of the methylperillate biosynthesis pathway from Salvia dorisiana trichomes.

J Exp Bot 2020 05;71(10):3052-3065

Wageningen Plant Research, 6700 AA, Wageningen, The Netherlands.

Plants produce a large variety of highly functionalized terpenoids. Functional groups such as partially unsaturated rings and carboxyl groups provide handles to use these compounds as feedstock for biobased commodity chemicals. For instance, methylperillate, a monoterpenoid found in Salvia dorisiana, may be used for this purpose, as it carries both an unsaturated ring and a methylated carboxyl group. The biosynthetic pathway of methylperillate in plants is still unclear. In this work, we identified glandular trichomes from S. dorisiana as the location of biosynthesis and storage of methylperillate. mRNA from purified trichomes was used to identify four genes that can encode the pathway from geranyl diphosphate towards methylperillate. This pathway includes a (-)-limonene synthase (SdLS), a limonene 7-hydroxylase (SdL7H, CYP71A76), and a perillyl alcohol dehydrogenase (SdPOHDH). We also identified a terpene acid methyltransferase, perillic acid O-methyltransferase (SdPAOMT), with homology to salicylic acid OMTs. Transient expression in Nicotiana benthamiana of these four genes, in combination with a geranyl diphosphate synthase to boost precursor formation, resulted in production of methylperillate. This demonstrates the potential of these enzymes for metabolic engineering of a feedstock for biobased commodity chemicals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jxb/eraa086DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7260718PMC
May 2020

Clinical and Biomechanical Outcomes of One-Stage Treatment of a Simultaneous Ipsilateral Patellar Tendon and ACL Tear Combined with a Tibial Plateau Fracture: A Case Study.

Case Rep Orthop 2020 4;2020:5793948. Epub 2020 Feb 4.

Department of Orthopaedics and Traumatology, University Hospital Basel, Spitalstrasse 21, 4031 Basel, Switzerland.

Simultaneous ipsilateral patellar tendon (PT) and anterior cruciate ligament (ACL) tear is a rare injury. Associated meniscal and ligamentous injuries are common but frequently initially missed. In contrast, to date, there is no report of associated fractures. We report on a 40-year-old female Caucasian patient presenting with a ski injury resulting in simultaneous ipsilateral patellar tendon and ACL tear combined with a tibia plateau fracture and a medial and lateral meniscus lesion. ORIF of the tibia as well as one-stage primary reconstruction of the PT and ACL and suturing of the menisci was conducted. The final follow-up was 2 years postoperatively. Lower extremity kinematic, kinetic, and muscle activity measurements were conducted. Although the clinical result was excellent, altered joint kinematics went along with large side-to-side difference in hip and knee joint moments during midstance and terminal stance. During weight acceptance, vastus medialis and hamstring muscles showed greater relative activity in the injured than the uninjured side. This case demonstrates the possibility of excellent early and midterm results with a one-stage approach and suitable rehabilitation scheme. Biomechanical measurements could further help evaluate the outcome of the treatments and implications for the development of potential secondary damage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2020/5793948DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7024102PMC
February 2020

Salinomycin Derivatives Kill Breast Cancer Stem Cells by Lysosomal Iron Targeting.

Chemistry 2020 Jun 17;26(33):7416-7424. Epub 2020 Apr 17.

Institut Curie, 26 rue d'Ulm, 75248, Paris Cedex 05, France.

Salinomycin (1) exhibits a large spectrum of biological activities including the capacity to selectively eradicate cancer stem cells (CSC), making it and its derivatives promising candidates for the development of drug leads against CSC. It has been previously shown that salinomycin and its C20-propargylamine derivative (Ironomycin (2)) accumulate in lysosomes and sequester iron in this organelle. Herein, a library of salinomycin derivatives is reported, including products of C20-amination, C1-esterification, C9-oxidation, and C28-dehydration. The biological activity of these compounds is evaluated against transformed human mammary epithelial HMLER CD24 /CD44 cells, a well-established model of breast CSC, and HMLER CD24 /CD44 cells deprived of CSC properties. Unlike other structural alterations, derivative 4, which displays a cyclopropylamine at position C20, showed a strikingly low IC value of 23 nm against HMLER CD24 /CD44 cells. This study provides highly selective molecules to target the CSC niche, a potential interesting advance for drug development to prevent cancer resistance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/chem.202000335DOI Listing
June 2020

DMT1 Inhibitors Kill Cancer Stem Cells by Blocking Lysosomal Iron Translocation.

Chemistry 2020 Jun 26;26(33):7369-7373. Epub 2020 May 26.

Institut Curie, 26 rue d'Ulm, 75248, Paris Cedex 05, France.

Cancer stem cells (CSC) constitute a cell subpopulation in solid tumors that is responsible for resistance to conventional chemotherapy, metastasis and cancer relapse. The natural product Salinomycin can selectively target this cell niche by directly interacting with lysosomal iron, taking advantage of upregulated iron homeostasis in CSC. Here, inhibitors of the divalent metal transporter 1 (DMT1) have been identified that selectively target CSC by blocking lysosomal iron translocation. This leads to lysosomal iron accumulation, production of reactive oxygen species and cell death with features of ferroptosis. DMT1 inhibitors selectively target CSC in primary cancer cells and circulating tumor cells, demonstrating the physiological relevance of this strategy. Taken together, this opens up opportunities to tackle unmet needs in anti-cancer therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/chem.202000159DOI Listing
June 2020

Whole-genome mapping of small-molecule targets for cancer medicine.

Curr Opin Chem Biol 2020 06 21;56:42-50. Epub 2020 Jan 21.

Institut Curie, 26 rue d'Ulm, 75248, Paris, Cedex 05, France; PSL Université Paris, France; Chemical Biology of Cancer Laboratory, CNRS UMR 3666, INSERM U1143, France. Electronic address:

Cancers display intratumoral and intertumoral heterogeneity, which poses challenges to small-molecule intervention. Studying drug responses on a whole-genome and transcriptome level using next-generation sequencing has revolutionized our understanding of how small molecules intervene in cells, which helps us to study and potentially predict treatment outcomes. Some small molecules act directly at the genomic level by targeting DNA or chromatin proteins. Here, we review recent advances in establishing whole-genome and transcriptome maps of small-molecule targets, comprising chromatin components or downstream events. We also describe recent advances in studying drug responses using single-cell RNA and DNA sequencing. Furthermore, we discuss how this fundamental research can be taken forward to devise innovative personalized treatment modalities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cbpa.2019.12.005DOI Listing
June 2020

Extensive recombination challenges the utility of Sugarcane mosaic virus phylogeny and strain typing.

Sci Rep 2019 12 27;9(1):20067. Epub 2019 Dec 27.

University of Cambridge, Department of Plant Sciences, Cambridge, CB2 3EA, United Kingdom.

Sugarcane mosaic virus (SCMV) is distributed worldwide and infects three major crops: sugarcane, maize, and sorghum. The impact of SCMV is increased by its interaction with Maize chlorotic mottle virus which causes the synergistic maize disease maize lethal necrosis. Here, we characterised maize lethal necrosis-infected maize from multiple sites in East Africa, and found that SCMV was present in all thirty samples. This distribution pattern indicates that SCMV is a major partner virus in the East African maize lethal necrosis outbreak. Consistent with previous studies, our SCMV isolates were highly variable with several statistically supported recombination hot- and cold-spots across the SCMV genome. The recombination events generate conflicting phylogenetic signals from different fragments of the SCMV genome, so it is not appropriate to group SCMV genomes by simple similarity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-019-56227-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6934591PMC
December 2019

Image-Based Morphological Profiling Identifies a Lysosomotropic, Iron-Sequestering Autophagy Inhibitor.

Angew Chem Int Ed Engl 2020 03 24;59(14):5721-5729. Epub 2020 Jan 24.

Department of Chemical Biology, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany.

Chemical proteomics is widely applied in small-molecule target identification. However, in general it does not identify non-protein small-molecule targets, and thus, alternative methods for target identification are in high demand. We report the discovery of the autophagy inhibitor autoquin and the identification of its molecular mode of action using image-based morphological profiling in the cell painting assay. A compound-induced fingerprint representing changes in 579 cellular parameters revealed that autoquin accumulates in lysosomes and inhibits their fusion with autophagosomes. In addition, autoquin sequesters Fe in lysosomes, resulting in an increase of lysosomal reactive oxygen species and ultimately cell death. Such a mechanism of action would have been challenging to unravel by current methods. This work demonstrates the potential of the cell painting assay to deconvolute modes of action of small molecules, warranting wider application in chemical biology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.201913712DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7154763PMC
March 2020

Three anchor concepts for rotator cuff repair in standardized physiological and osteoporotic bone: a biomechanical study.

J Shoulder Elbow Surg 2020 Feb 6;29(2):e52-e59. Epub 2019 Oct 6.

University of Basel, Basel, Switzerland; Department of Orthopaedics and Traumatology, University Hospital Basel, Basel, Switzerland.

Background: Previous biomechanical studies used single-pull destructive tests in line with the anchor and are limited by a great variability of bone density of cadaver samples. To overcome these limitations, a more physiological test setting was provided using titanium, bioresorbable, and all-suture anchors.

Methods: In this controlled laboratory study, 3 anchor constructs were divided into 2 groups: physiological and osteoporotic. Sixty standardized artificial bone specimens (=10 for each anchor in each group) were used for biomechanical testing. The anchors were inserted at a 45° angle as during surgery. Cyclic loading for 1000 cycles followed by ultimate load-to-failure (ULTF) testing was performed. Elongation, ultimate load at failure, and the mode of failure were noted.

Results: In the physiological group, the ULTF for the all-suture anchor (mean [standard deviation], 632.9 [96.8 N]) was found to be significantly higher than for the other anchors (titanium, 497.1 [50.5] N, and bioresorbable, 322.4 [3.1 N], P < .0001). The titanium anchor showed a significantly higher ULTF than the bioresorbable anchor (P < .0001). In the osteoporotic group, the all-suture anchor again showed a higher ULTF compared to the bioresorbable anchor (500.9 [50.6] N vs. 315.1 [11.3] N, P < .0001). In the osteoporotic group, cyclic loading revealed a higher elongation after 1000 loading cycles for the bioresorbable (0.40 [0.12] mm) compared to the titanium (0.22 [0.11] mm; P = .01) as well as the all-suture anchor (0.19 [0.15] mm, P = .003).

Conclusion: Regarding ULTF, the all-suture anchor outperformed the other anchors in physiological bone, but in osteoporotic bone, significance was reached only compared to the bioresorbable anchor. Although cyclic loading revealed significant differences, these might not be clinically relevant.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jse.2019.07.032DOI Listing
February 2020

Design, Synthesis, and Biological Characterization of Orally Active 17β-Hydroxysteroid Dehydrogenase Type 2 Inhibitors Targeting the Prevention of Osteoporosis.

J Med Chem 2019 08 25;62(15):7289-7301. Epub 2019 Jul 25.

Department of Pharmaceutical and Medicinal Chemistry , Saarland University , 66123 Saarbrücken , Germany.

Osteoporosis is predominantly treated with drugs that inhibit further bone resorption due to estrogen deficiency. Yet, osteoporosis drugs that not only inhibit bone resorption but also stimulate bone formation, such as potentially inhibitors of 17β-hydroxysteroid dehydrogenase type 2 (17β-HSD2), may be more efficacious in the treatment of osteoporosis. Blockade of 17β-HSD2 is thought to increase intracellular estradiol and testosterone in bone, thereby inhibiting bone resorption by osteoclasts and stimulating bone formation by osteoblasts, respectively. We here describe the design, synthesis, and biological characterization of a novel bicyclic-substituted hydroxyphenylmethanone 17β-HSD2 inhibitor (compound ). Compound is a nanomolar potent inhibitor of human 17β-HSD2 (IC of 6.1 nM) and rodent 17β-HSD2 with low in vitro cellular toxicity, devoid of detectable estrogen receptor α affinity, displays high aqueous solubility and in vitro metabolic stability, and has an excellent oral pharmacokinetic profile for testing in a rat osteoporosis model. Administration of in a rat osteoporosis model demonstrates its bone-sparing efficacy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jmedchem.9b00932DOI Listing
August 2019

Test-Retest Reliability of Outpatient Telemetric Intracranial Pressure Measurements in Shunt-Dependent Patients with Hydrocephalus and Idiopathic Intracranial Hypertension.

World Neurosurg 2019 Nov 8;131:e74-e80. Epub 2019 Jul 8.

Department of Neurosurgery, University Medicine Göttingen, Georg-August University, Göttingen, Germany. Electronic address:

Background: Some patients with hydrocephalus and idiopathic intracranial hypertension treated for elevated intracranial pressure (ICP) with a cerebrospinal fluid shunt may continue to experience symptoms or develop new symptoms despite valve adjustments. Use of telemetric ICP measurements may help confirm clinical suspicion of cerebrospinal fluid underdrainage or overdrainage in these patients. However, point in time, duration, and activity during the measurements have never been standardized. We devised a simple, repeatable maneuver for outpatient telemetric ICP recording and evaluated its test-retest reliability.

Methods: Data of patients who underwent ventriculoperitoneal or ventriculoatrial shunt placement and subsequent telemetric ICP sensor implantation were retrospectively reviewed. Telemetric ICP recordings in patients were conducted in a standardized manner: The standing-supine-sitting paradigm requires postural changes in 10-minute intervals over 30 minutes. First, the patient is requested to walk; second, to lay down; third, to sit down with a headrest elevation of 60°. ICP data (in mmHg) were reported as mean ± SD values. Test-retest validity was assessed using Pearson correlation analysis.

Results: We evaluated 66 ICP datasets obtained repeatedly with a time difference of at least 24 hours. Overall test-retest reliability was excellent (Pearson correlation coefficient 0.99, P < 0.001), as were the scores for individual postures: standing (correlation 0.98, P < 0.001), supine (correlation 0.98, P < 0.001), and sitting (correlation 0.99, P < 0.001). The sum of square differences of the test-retest measures reflected a comparable validity of all tested positions.

Conclusions: We confirmed high test-retest reliability of the standing-supine-sitting paradigm for telemetric ICP measurements in the outpatient setting. High test-retest reliability should be considered as prerequisite for clinical decision making.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.wneu.2019.07.014DOI Listing
November 2019

The new LassoLoop360° technique for biomechanically superior tissue grip.

Knee Surg Sports Traumatol Arthrosc 2019 Dec 28;27(12):3962-3969. Epub 2019 Jun 28.

University of Basel, Petersplatz 1, 4003, Basel, Switzerland.

Purpose: Suprapectoral tenodesis is a frequently used technique for treating pathologies of the long head of the biceps brachii (LHBB) tendon. However, so far, no Gold Standard treatment exist. Hence, the arthroscopic LassoLoop360 (LL360) technique is introduced aiming to provide secure fixation and improved biomechanical properties. It was hypothesized, that the LL360 technique would show superior biomechanical response to cyclic loading and ultimate load-to-failure testing compared to the commonly used simple Lasso Loop (SLL).

Methods: Twenty-two porcine superficial flexor digitorum tendons were prepared using a No. 2 suture according to either the SLL or the LL360 technique. Displacement after cyclic loading (1.000 cycles) between 5 and 30 N, ultimate load-to-failure (ULTF), mode of failure as well as the construct stiffness were tested.

Results: Significantly less displacement was found in the LL360 group (SLL 2.25 ± 0.51 mm; LL360 1.67 ± 0.37 mm; p = 0.01). Ultimate Load to Failure was significantly higher in the LL360 (168.6 ± 29.6 N) as compared to the SLL (124.1 ± 25.8 N, p = 0.02). The LL360 also revealed a significant higher stiffness compared to the SLL (SLL 13.1 ± 0.9 N/mm vs. LL360 19.1 ± 1.0 N/mm, p < 0.001). The most common mode of failure was the suture cutting through the tendon, with a significantly less suture cutting through for the LL360 compared with the SLL (p < 0.05).

Conclusion: The LassoLoop360-technique offers superior biomechanical characteristics regarding the tendon-suture-interface compared to the SLL. In the initial healing phase, the suture-tendon-interface is the most vulnerable part of the tendon-suture-anchor construct, the aim of this new technique is to reduce this weakest part of the chain (Ponce et al., Am J Sports Med 39:188-194, 2011). This technique may therefore be beneficial for arthroscopic suprapectoral biceps tenodesis at the entrance of the bicipital groove.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00167-019-05604-1DOI Listing
December 2019

Effects of 17β-HSD2 inhibition in bones on osteoporosis based on an animal rat model.

J Steroid Biochem Mol Biol 2019 09 8;192:105405. Epub 2019 Jun 8.

Technische Universität Dresden, Molecular Cell Physiology and Endocrinology, Institute for Zoology, Dresden, Germany. Electronic address:

Hormone replacement therapy is a viable option to protect bone from postmenopausal osteoporosis. Systemically elevated estrogen levels, however, are disadvantageous because of the risk of harmful side effects in other organs. The rationale of the study presented here is to target a key enzyme in estradiol (E2) and testosterone (T) metabolism to increase E2 levels in an organ-specific manner, thereby avoiding the disadvantages of systemically increased E2 levels. The 17ß-hydroxysteroid dehydrogenase (17β-HSD2), which is e.g. expressed in bone, catalyzes the oxidation of E2 and T into estrone (E1) and androstenedione. We postulate that inhibiting 17β-HSD2 should lead to elevated E2 and T levels in organs expressing the enzyme. Therefore, we can use the benefits of E2 directly, or those of T following aromatization into E2, in the bone without affecting systemic levels. We tested for the first time, the novel and potent 17β-HSD2 inhibitor, compound 24 (C24), to explore the therapeutic potential of a 17β-HSD2 inhibition in an ovariectomy (ovx)-induced rat model of bone loss. We tested the inhibitor alone and, together with low dose estrogen supplementation to model estrogen levels in the postmenopausal situation. Female mature Wistar-Hannover rats were treated for 8 weeks with doses of 2, 10, 50 mg C24 per kg body weight per day alone or in the presence of estradiol benzoate (E2B) supplementation to alleviate ovx-induced bone loss. Ovx placebo and sham operated animals served as negative and positive controls. The experiment was evaluated regarding aspects of efficacy and safety: Bone was analyzed to evaluate bone protective effects, and uterus for potential, unwanted E2-mediated side effects. We observed a good bioavailability of C24 as very high plasma concentrations were measured, up to a group mean of 15,412 nM for the ovx C24-high group. Histomorphometrical analyses and in vivo &ex vivo μCT revealed significant bone protective effects for the lowest inhibitor concentration used. Irrespective of the plasma concentration, no proliferative effects in the uterus could be observed. These results support our approach of intracellular targeting key enzymes of E2 and T metabolism to increase E2 and T levels in an organ specific manner.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jsbmb.2019.105405DOI Listing
September 2019

Analysis of 1508 Plasma Samples by Capillary-Flow Data-Independent Acquisition Profiles Proteomics of Weight Loss and Maintenance.

Mol Cell Proteomics 2019 06 4;18(6):1242-1254. Epub 2019 Apr 4.

From the ‡Biognosys, 8952 Zurich-Schlieren, Switzerland;

Comprehensive, high throughput analysis of the plasma proteome has the potential to enable holistic analysis of the health state of an individual. Based on our own experience and the evaluation of recent large-scale plasma mass spectrometry (MS) based proteomic studies, we identified two outstanding challenges: slow and delicate nano-flow liquid chromatography (LC) and irreproducibility of identification of data-dependent acquisition (DDA). We determined an optimal solution reducing these limitations with robust capillary-flow data-independent acquisition (DIA) MS. This platform can measure 31 plasma proteomes per day. Using this setup, we acquired a large-scale plasma study of the diet, obesity and genes dietary (DiOGenes) comprising 1508 samples. Proving the robustness, the complete acquisition was achieved on a single analytical column. Totally, 565 proteins (459 identified with two or more peptide sequences) were profiled with 74% data set completeness. On average 408 proteins (5246 peptides) were identified per acquisition (319 proteins in 90% of all acquisitions). The workflow reproducibility was assessed using 34 quality control pools acquired at regular intervals, resulting in 92% data set completeness with CVs for protein measurements of 10.9%.The profiles of 20 apolipoproteins could be profiled revealing distinct changes. The weight loss and weight maintenance resulted in sustained effects on low-grade inflammation, as well as steroid hormone and lipid metabolism, indicating beneficial effects. Comparison to other large-scale plasma weight loss studies demonstrated high robustness and quality of biomarker candidates identified. Tracking of nonenzymatic glycation indicated a delayed, slight reduction of glycation in the weight maintenance phase. Using stable-isotope-references, we could directly and absolutely quantify 60 proteins in the DIA.In conclusion, we present herein the first large-scale plasma DIA study and one of the largest clinical research proteomic studies to date. Application of this fast and robust workflow has great potential to advance biomarker discovery in plasma.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/mcp.RA118.001288DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6553938PMC
June 2019