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  1. Article ; Online: Long-circulating XTEN864-annexin A5 fusion protein for phosphatidylserine-related therapeutic applications.

    Haeckel, Akvile / Ascher, Lena / Beindorff, Nicola / Prasad, Sonal / Garczyńska, Karolina / Guo, Jing / Schellenberger, Eyk

    Apoptosis : an international journal on programmed cell death

    2021  Volume 26, Issue 9-10, Page(s) 534–547

    Abstract: Annexin A5 (anxA5) is a marker for apoptosis, but has also therapeutic potential in cardiovascular diseases, cancer, and, due to apoptotic mimicry, against dangerous viruses, which is limited by the short blood circulation. An 864-amino-acid XTEN ... ...

    Abstract Annexin A5 (anxA5) is a marker for apoptosis, but has also therapeutic potential in cardiovascular diseases, cancer, and, due to apoptotic mimicry, against dangerous viruses, which is limited by the short blood circulation. An 864-amino-acid XTEN polypeptide was fused to anxA5. XTEN864-anxA5 was expressed in Escherichia coli and purified using XTEN as tag. XTEN864-anxA5 was coupled with DTPA and indium-111. After intravenous or subcutaneous injection of
    MeSH term(s) Animals ; Annexin A5/genetics ; Annexin A5/metabolism ; Apoptosis ; Escherichia coli/metabolism ; Mice ; Phosphatidylserines ; Tissue Distribution
    Chemical Substances Annexin A5 ; Phosphatidylserines
    Language English
    Publishing date 2021-08-17
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1452360-7
    ISSN 1573-675X ; 1360-8185
    ISSN (online) 1573-675X
    ISSN 1360-8185
    DOI 10.1007/s10495-021-01686-w
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Multiplex enzyme activity imaging by MALDI-IMS of substrate library conversions

    Oliver Klein / Akvile Haeckel / Ulf Reimer / Grit Nebrich / Eyk Schellenberger

    Scientific Reports, Vol 10, Iss 1, Pp 1-

    2020  Volume 11

    Abstract: Abstract Enzymes are fundamental to biological processes and involved in most pathologies. Here we demonstrate the concept of simultaneously mapping multiple enzyme activities (EA) by applying enzyme substrate libraries to tissue sections and analyzing ... ...

    Abstract Abstract Enzymes are fundamental to biological processes and involved in most pathologies. Here we demonstrate the concept of simultaneously mapping multiple enzyme activities (EA) by applying enzyme substrate libraries to tissue sections and analyzing their conversion by matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS). To that end, we spray-applied a solution of 20 naturally derived peptides that are known substrates for proteases, kinases, and phosphatases to zinc-fixed paraffin tissue sections of mouse kidneys. After enzyme conversion for 5 to 120 min at 37 °C and matrix application, the tissue sections were imaged by MALDI-IMS. We could image incubation time-dependently 16 of the applied substrates with differing signal intensities and 12 masses of expected products. Utilizing inherent enzyme amplification, EA-IMS can become a powerful tool to locally study multiple, potentially even lowly expressed, enzyme activities, networks, and their pharmaceutical modulation. Differences in the substrate detectability highlight the need for future optimizations.
    Keywords Medicine ; R ; Science ; Q
    Language English
    Publishing date 2020-09-01T00:00:00Z
    Publisher Nature Publishing Group
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Multiplex enzyme activity imaging by MALDI-IMS of substrate library conversions.

    Klein, Oliver / Haeckel, Akvile / Reimer, Ulf / Nebrich, Grit / Schellenberger, Eyk

    Scientific reports

    2020  Volume 10, Issue 1, Page(s) 15522

    Abstract: Enzymes are fundamental to biological processes and involved in most pathologies. Here we demonstrate the concept of simultaneously mapping multiple enzyme activities (EA) by applying enzyme substrate libraries to tissue sections and analyzing their ... ...

    Abstract Enzymes are fundamental to biological processes and involved in most pathologies. Here we demonstrate the concept of simultaneously mapping multiple enzyme activities (EA) by applying enzyme substrate libraries to tissue sections and analyzing their conversion by matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS). To that end, we spray-applied a solution of 20 naturally derived peptides that are known substrates for proteases, kinases, and phosphatases to zinc-fixed paraffin tissue sections of mouse kidneys. After enzyme conversion for 5 to 120 min at 37 °C and matrix application, the tissue sections were imaged by MALDI-IMS. We could image incubation time-dependently 16 of the applied substrates with differing signal intensities and 12 masses of expected products. Utilizing inherent enzyme amplification, EA-IMS can become a powerful tool to locally study multiple, potentially even lowly expressed, enzyme activities, networks, and their pharmaceutical modulation. Differences in the substrate detectability highlight the need for future optimizations.
    MeSH term(s) Animals ; Enzymes/metabolism ; Enzymes/ultrastructure ; Humans ; Molecular Imaging/methods ; Peptides/metabolism ; Protein Interaction Mapping/methods ; Small Molecule Libraries/metabolism ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods
    Chemical Substances Enzymes ; Peptides ; Small Molecule Libraries
    Language English
    Publishing date 2020-09-23
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-020-72436-2
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Bioresponsive nanosensors in medical imaging.

    Schellenberger, Eyk

    Journal of the Royal Society, Interface

    2009  Volume 7 Suppl 1, Page(s) S83–91

    Abstract: Superparamagnetic iron oxide nanoparticles have been established as sensitive probes for magnetic resonance imaging (MRI). While the majority of specific nanosensors are based on sterically stabilized iron oxide particles, the focus of this review is on ... ...

    Abstract Superparamagnetic iron oxide nanoparticles have been established as sensitive probes for magnetic resonance imaging (MRI). While the majority of specific nanosensors are based on sterically stabilized iron oxide particles, the focus of this review is on the use of very small iron oxide particles (VSOPs) that are electrostatically stabilized by an anionic citrate acid shell. We used VSOPs to develop target-specific as well as protease-activatable nanosensors for molecular MRI.
    MeSH term(s) Annexins/chemistry ; Apoptosis/physiology ; Citric Acid/chemistry ; Diagnostic Imaging/instrumentation ; Diagnostic Imaging/methods ; Ferric Compounds/chemistry ; Fluorescent Dyes ; Magnetic Resonance Imaging/methods ; Magnetics ; Models, Molecular ; Nanostructures ; Static Electricity
    Chemical Substances Annexins ; Ferric Compounds ; Fluorescent Dyes ; ferric oxide (1K09F3G675) ; Citric Acid (2968PHW8QP)
    Language English
    Publishing date 2009-10-21
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 2156283-0
    ISSN 1742-5662 ; 1742-5689
    ISSN (online) 1742-5662
    ISSN 1742-5689
    DOI 10.1098/rsif.2009.0336.focus
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Missense variants in ANO4 cause sporadic encephalopathic or familial epilepsy with evidence for a dominant-negative effect.

    Yang, Fang / Begemann, Anais / Reichhart, Nadine / Haeckel, Akvile / Steindl, Katharina / Schellenberger, Eyk / Sturm, Ronja Fini / Barth, Magalie / Bassani, Sissy / Boonsawat, Paranchai / Courtin, Thomas / Delobel, Bruno / Gunning, Boudewijn / Hardies, Katia / Jennesson, Mélanie / Legoff, Louis / Linnankivi, Tarja / Prouteau, Clément / Smal, Noor /
    Spodenkiewicz, Marta / Toelle, Sandra P / Van Gassen, Koen / Van Paesschen, Wim / Verbeek, Nienke / Ziegler, Alban / Zweier, Markus / Horn, Anselm H C / Sticht, Heinrich / Lerche, Holger / Weckhuysen, Sarah / Strauß, Olaf / Rauch, Anita

    American journal of human genetics

    2024  

    Abstract: Anoctamins are a family of ... ...

    Abstract Anoctamins are a family of Ca
    Language English
    Publishing date 2024-05-10
    Publishing country United States
    Document type Journal Article
    ZDB-ID 219384-x
    ISSN 1537-6605 ; 0002-9297
    ISSN (online) 1537-6605
    ISSN 0002-9297
    DOI 10.1016/j.ajhg.2024.04.014
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Iron(III)-tCDTA derivatives as MRI contrast agents: Increased T

    Xie, Jing / Haeckel, Akvile / Hauptmann, Ralf / Ray, Iweta Pryjomska / Limberg, Christian / Kulak, Nora / Hamm, Bernd / Schellenberger, Eyk

    Magnetic resonance in medicine

    2021  Volume 85, Issue 6, Page(s) 3370–3382

    Abstract: Purpose: Low molecular weight iron(III) complex-based contrast agents (IBCA) including iron(III) trans-cyclohexane diamine tetraacetic acid [Fe(tCDTA)]: Methods: Trans-cyclohexane diamine tetraacetic acid (tCDTA) was chemically modified in 2 steps: ... ...

    Abstract Purpose: Low molecular weight iron(III) complex-based contrast agents (IBCA) including iron(III) trans-cyclohexane diamine tetraacetic acid [Fe(tCDTA)]
    Methods: Trans-cyclohexane diamine tetraacetic acid (tCDTA) was chemically modified in 2 steps: first the monoanhydride of Trans-cyclohexane diamine tetraacetic acid was generated, and then it was coupled to amines in the second step. After purification, the chelators were analyzed by high-performance liquid chromatography, mass spectrometry, and NMR spectrometry. The chelators were complexed with iron(III), and the relaxivities of the complexes were measured at 0.94, 1.5, 3, and 7 Tesla. Kinetic stabilities of the complexes were analyzed spectrophotometrically and the redox properties by cyclic voltammetry.
    Results: Using ethylenediamine (en) and trans-1,4-diaminocyclohexane, we generated monomers and dimers of tCDTA: en-tCDTA, en-tCDTA-dimer, trans-1,4-diaminocyclohexane-tCDTA, and trans-1,4-diaminocyclohexane-tCDTA-dimer. The iron(III) complexes of these derivatives had similarly high stabilities as [Fe(tCDTA)]
    Conclusion: Four iron(III) complexes with similar stability in comparison to [Fe(tCDTA)]
    MeSH term(s) Contrast Media ; Hydrogen-Ion Concentration ; Iron ; Magnetic Fields ; Magnetic Resonance Imaging
    Chemical Substances Contrast Media ; Iron (E1UOL152H7)
    Language English
    Publishing date 2021-02-04
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 605774-3
    ISSN 1522-2594 ; 0740-3194
    ISSN (online) 1522-2594
    ISSN 0740-3194
    DOI 10.1002/mrm.28664
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Determination of Methemoglobin in Hemoglobin Submicron Particles Using NMR Relaxometry.

    Kaewprayoon, Waraporn / Suwannasom, Nittiya / Kloypan, Chiraphat / Steffen, Axel / Xiong, Yu / Schellenberger, Eyk / Pruß, Axel / Georgieva, Radostina / Bäumler, Hans

    International journal of molecular sciences

    2020  Volume 21, Issue 23

    Abstract: Methemoglobin (MetHb) is a hemoglobin (Hb) derivative with the heme iron in ferric state ( ... ...

    Abstract Methemoglobin (MetHb) is a hemoglobin (Hb) derivative with the heme iron in ferric state (Fe
    MeSH term(s) Cross-Linking Reagents/chemistry ; Erythrocytes/metabolism ; Glutaral/chemistry ; Hemoglobins/analysis ; Hemoglobins/ultrastructure ; Humans ; Magnetic Resonance Spectroscopy ; Methemoglobin/analysis ; Methemoglobin/ultrastructure ; Serum Albumin, Human/chemistry ; Solutions
    Chemical Substances Cross-Linking Reagents ; Hemoglobins ; Solutions ; Methemoglobin (9008-37-1) ; Glutaral (T3C89M417N) ; Serum Albumin, Human (ZIF514RVZR)
    Language English
    Publishing date 2020-11-26
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2019364-6
    ISSN 1422-0067 ; 1422-0067 ; 1661-6596
    ISSN (online) 1422-0067
    ISSN 1422-0067 ; 1661-6596
    DOI 10.3390/ijms21238978
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  8. Article: Optische Bildgebung: Anwendungen.

    Schellenberger, Eyk

    Zeitschrift fur medizinische Physik

    2005  Volume 15, Issue 3, Page(s) 187–191

    Abstract: Optical imaging in the form of near infrared fluorescence and bioluminescence has proven useful for a wide range of applications in the field of molecular imaging. Both techniques provide a high sensitivity (in the nanomolar range), which is of ... ...

    Title translation Applications of optical imaging.
    Abstract Optical imaging in the form of near infrared fluorescence and bioluminescence has proven useful for a wide range of applications in the field of molecular imaging. Both techniques provide a high sensitivity (in the nanomolar range), which is of particular importance for molecular imaging. Imaging with near infrared fluorescence is especially cost-effective and can be performed, in contrast to radioactivity-based methods, with fluorescence dyes that remain stable for months. The most important advantage of bioluminescence, in turn, is the lack of background signal. Although molecular imaging with these techniques is still in the experimental phase, an application of near infrared fluorescence is already foreseeable for the imaging of superficial structures.
    MeSH term(s) Animals ; Apoptosis ; Diagnostic Imaging ; Infrared Rays ; Luciferases ; Luminescent Measurements ; Models, Animal ; Models, Molecular ; Neoplasms/pathology ; Neoplasms/therapy ; Phantoms, Imaging ; Rats
    Chemical Substances Luciferases (EC 1.13.12.-)
    Language German
    Publishing date 2005-09-08
    Publishing country Germany
    Document type English Abstract ; Journal Article
    ZDB-ID 1104517-6
    ISSN 1876-4436 ; 0939-3889 ; 0040-5973
    ISSN (online) 1876-4436
    ISSN 0939-3889 ; 0040-5973
    DOI 10.1078/0939-3889-00269
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  9. Article ; Online: Macrophage uptake switches on OCT contrast of superparamagnetic nanoparticles for imaging of atherosclerotic plaques.

    Ariza de Schellenberger, Angela / Poller, Wolfram C / Stangl, Verena / Landmesser, Ulf / Schellenberger, Eyk

    International journal of nanomedicine

    2018  Volume 13, Page(s) 7905–7913

    Abstract: Background: Optical coherence tomography (OCT) is an intravascular, high-resolution imaging technique that is used to characterize atherosclerotic plaques. However, the identification of macrophages as important markers of inflammation and plaque ... ...

    Abstract Background: Optical coherence tomography (OCT) is an intravascular, high-resolution imaging technique that is used to characterize atherosclerotic plaques. However, the identification of macrophages as important markers of inflammation and plaque vulnerability remains difficult. Here, we investigate whether the uptake of very small iron oxide particles (VSOP) in macrophages, that cluster in phagolysosomes and allow high-quality magnetic resonance imaging (MRI) of atherosclerotic plaques, and uptake of ferumoxytol nanoparticles enhance detection of macrophages by OCT.
    Materials and methods: RAW 264.7 macrophage cells were incubated with VSOP (1 and 2 mM Fe) that have been clinically tested and ferumoxytol (8.9 mM Fe) that is approved for iron deficiency treatment and currently investigated as an MRI contrast agent. The light scattering of control macrophages, nanoparticle-labeled macrophages (2,000,000 in 500 µL) and nanoparticle suspensions was measured in synchronous wavelength scan mode using a fluorescence spectrophotometer. For OCT analyses, pellets of 8,000,000 non-labeled, VSOP-labeled and ferumoxytol-labeled RAW 264.7 macrophages were imaged and analyzed on an OPTIS™ OCT imaging system.
    Results: Incubation with 1 and 2 mM VSOP resulted in uptake of 7.1±1.5 and 12±1.5 pg Fe per cell, which increased the backscattering of the macrophages in spectrophotometry 2.5- and 3.6-fold, whereas incubation with 8.9 mM Fe ferumoxytol resulted in uptake of 6.6±2 pg Fe per cell, which increased the backscattering 1.5-fold at 700 nm. In contrast, backscattering of non-clustered nanoparticles in suspension was negligible. Accordingly, OCT imaging could visualize significantly increased backscattering and signal attenuation of nanoparticle-labeled macrophages in comparison with controls.
    Conclusion: We conclude that VSOP and, to a lesser extent, ferumoxytol increase light scattering and attenuation when taken up by macrophages and can serve as a multimodal imaging probe for MRI and OCT to improve macrophage detection in atherosclerotic plaques by OCT in the future.
    MeSH term(s) Animals ; Contrast Media/chemistry ; Endocytosis ; Ferric Compounds/chemistry ; Ferrosoferric Oxide/chemistry ; Humans ; Light ; Macrophages/metabolism ; Macrophages/pathology ; Magnetic Resonance Imaging/methods ; Magnetite Nanoparticles/chemistry ; Mice ; Particle Size ; Phantoms, Imaging ; Plaque, Atherosclerotic/diagnostic imaging ; Plaque, Atherosclerotic/pathology ; Plaque, Atherosclerotic/ultrastructure ; RAW 264.7 Cells ; Scattering, Radiation ; Staining and Labeling ; Tomography, Optical Coherence
    Chemical Substances Contrast Media ; Ferric Compounds ; Magnetite Nanoparticles ; ferric oxide (1K09F3G675) ; Ferrosoferric Oxide (XM0M87F357)
    Language English
    Publishing date 2018-11-23
    Publishing country New Zealand
    Document type Journal Article
    ZDB-ID 2364941-0
    ISSN 1178-2013 ; 1176-9114
    ISSN (online) 1178-2013
    ISSN 1176-9114
    DOI 10.2147/IJN.S179920
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  10. Article ; Online: XTEN as Biological Alternative to PEGylation Allows Complete Expression of a Protease-Activatable Killin-Based Cytostatic.

    Haeckel, Akvile / Appler, Franziska / Ariza de Schellenberger, Angela / Schellenberger, Eyk

    PloS one

    2016  Volume 11, Issue 6, Page(s) e0157193

    Abstract: Increased effectiveness and reduced side effects are general goals in drug research, especially important in cancer therapy. The aim of this study was to design a long-circulating, activatable cytostatic drug that is completely producible in E. coli. ... ...

    Abstract Increased effectiveness and reduced side effects are general goals in drug research, especially important in cancer therapy. The aim of this study was to design a long-circulating, activatable cytostatic drug that is completely producible in E. coli. Crucial for this goal was the novel unstructured polypeptide XTEN, which acts like polyethylene glycol (PEG) but has many important advantages. Most importantly, it can be produced in E. coli, is less immunogenic, and is biodegradable. We tested constructs containing a fragment of Killin as cytostatic/cytotoxic element, a cell-penetrating peptide, an MMP-2 cleavage site for specific activation, and XTEN for long blood circulation and deactivation of Killin. One of three sequence variants was efficiently expressed in E. coli. As typical for XTEN, it allowed efficient purification of the E. coli lysate by a heat step (10 min 75°C) and subsequent anion exchange chromatography using XTEN as purification tag. After 24 h XTEN-Killin reduced the number of viable cells of HT-1080 tumor cell line to 3.8 ±2.0% (p<0.001) compared to untreated controls. In contrast, liver derived non-tumor cells (BRL3A) did not show significant changes in viability. Our results demonstrate the feasibility of completely producing a complex protease-activatable, potentially long-circulating cytostatic/cytotoxic prodrug in E. coli-a concept that could lead to efficient production of highly multifunctional drugs in the future.
    MeSH term(s) Antineoplastic Agents/metabolism ; Antineoplastic Agents/pharmacology ; Apoptosis/drug effects ; Cell Line ; Cell Line, Tumor ; Cell Proliferation/drug effects ; Cell-Penetrating Peptides/genetics ; Cell-Penetrating Peptides/metabolism ; Cell-Penetrating Peptides/pharmacology ; Escherichia coli/genetics ; Humans ; Matrix Metalloproteinase 2/metabolism ; Neoplasms/drug therapy ; Neoplasms/metabolism ; Prodrugs/metabolism ; Prodrugs/pharmacology ; Recombinant Fusion Proteins/genetics ; Recombinant Fusion Proteins/metabolism ; Recombinant Fusion Proteins/pharmacology ; Tumor Suppressor Proteins/genetics ; Tumor Suppressor Proteins/metabolism ; Tumor Suppressor Proteins/pharmacology
    Chemical Substances Antineoplastic Agents ; Cell-Penetrating Peptides ; KLLN protein, human ; Prodrugs ; Recombinant Fusion Proteins ; Tumor Suppressor Proteins ; Matrix Metalloproteinase 2 (EC 3.4.24.24)
    Language English
    Publishing date 2016-06-13
    Publishing country United States
    Document type Journal Article
    ISSN 1932-6203
    ISSN (online) 1932-6203
    DOI 10.1371/journal.pone.0157193
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