TY - JOUR A1 - Fusi, Lorenza A1 - Paudel, Rupesh A1 - Meder, Katharina A1 - Schlosser, Andreas A1 - Schrama, David A1 - Goebeler, Matthias A1 - Schmidt, Marc T1 - Interaction of transcription factor FoxO3 with histone acetyltransferase complex subunit TRRAP modulates gene expression and apoptosis JF - Journal of Biological Chemistry N2 - Forkhead box O (FoxO) transcription factors are conserved proteins involved in the regulation of life span and age-related diseases, such as diabetes and cancer. Stress stimuli or growth factor deprivation promotes nuclear localization and activation of FoxO proteins, which—depending on the cellular context—can lead to cell cycle arrest or apoptosis. In endothelial cells (ECs), they further regulate angiogenesis and may promote inflammation and vessel destabilization implicating a role of FoxOs in vascular diseases. In several cancers, FoxOs exert a tumor-suppressive function by regulating proliferation and survival. We and others have previously shown that FoxOs can regulate these processes via two different mechanisms: by direct binding to forkhead-responsive elements at the promoter of target genes or by a poorly understood alternative process that does not require direct DNA binding and regulates key targets in primary human ECs. Here, we performed an interaction study in ECs to identify new nuclear FoxO3 interaction partners that might contribute to FoxO-dependent gene regulation. Mass spectrometry analysis of FoxO3-interacting proteins revealed transformation/transcription domain–associated protein (TRRAP), a member of multiple histone acetyltransferase complexes, as a novel binding partner of FoxO family proteins. We demonstrate that TRRAP is required to support FoxO3 transactivation and FoxO3-dependent G1 arrest and apoptosis in ECs via transcriptional activation of the cyclin-dependent kinase inhibitor p27\(^{kip1}\) and the proapoptotic B-cell lymphoma 2 family member, BIM. Moreover, FoxO–TRRAP interaction could explain FoxO-induced alternative gene regulation via TRRAP-dependent recruitment to target promoters lacking forkhead-responsive element sequences. KW - FoxO3 KW - TRRAP KW - transcription factors Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-299820 VL - 298 IS - 3 ER - TY - THES A1 - Schmidt, Andreas T1 - Nah- und Fernfeldableitungen der Hörbahn bei Operationen von Vestibularisschwannomen T1 - Nearfield and farfield monitoring of auditory function in vestibular schwannoma surgery N2 - Einführung und Zielsetzung: Die intraoperative Ableitung von ABRs (auditory brainstem responses) ist eine Standardmethode für das Monitoring der Hörbahn bei der Operation von Vestibularisschwannomen. Als Fernfeldtechnologie zeigt sich diese Methode jedoch oft limitiert. Ziel dieser Arbeit ist, den zusätzlichen Einsatz einer nicht-invasiven Elektrocochleographie (ECochG) als Nahfeldtechnologie zu evaluieren. Methoden: Hierzu erfolgte retrospektive Auswertung und Klassifikation von elektrophysiologischen Monitoring Daten von 69 Patienten, welche zwischen 2010 und 2014 mittels retrosigmoidalen Zugang am Vestibularisschwannom operiert wurden. Die ECochG wurde bei diesen Patienten simultan zu den ABR mit einer ans Trommelfell platzierten Kugelelektrode abgeleitet. Die Patientenselektion für diese Studie erfolgte vor allem nach dem Wunsch des Patienten gehörerhaltend operiert zu werden, unabhängig von Tumorausdehnung (von klein bis Hirnstamm komprimierend) oder der präoperativer Hörqualität. Es erfolgte Korrelation mit der prä- und postoperativen Hörqualität. Ergebnisse: Präoperativ zeigen die ABR- und ECochG-Klassen nahezu dieselbe Verteilung und Korrelation mit der präoperativen Hörklasse. Allerdings zeigt, wie initial vermutet, die postoperative ECochG schwächere Korrelation mit der postoperativen Hörqualität, als die ABRs: 25 von 43 Patienten mit postoperativer Taubheit zeigten in der ECochG am Ende der OP immer noch cochleäre Potentiale. Neben der cochleären Funktion kann mit der nicht-invasiven ECochG die Hörbahn analog zum ABR dargestellt werden. Die Identifizierbarkeit besonders der späteren Komponenten (Welle III und V) ist mit der nicht-invasiven Elektrocochleographie mindestens genauso gut möglich wie mit den ABR. Weiter liefert die ECochG signifikant größere Amplituden. Der Vergleich der ABR- mit den ECochG-Klassen liefert stark positive Korrelationen. Dies gilt vor allem für die Klassen 1 bis 3, in denen die Welle V noch vorhanden ist. Schlussfolgerung: Die signifikant größeren Amplituden der ECochG erlauben kürzere Messzeiten. Dies bietet intraoperativ Sicherheit für den Fall von Artefakten oder technischen Störungen sowie Vorteile in technisch schwierigen Phasen der OP. Neben der cochleären Funktion kann mit der ECochG die Hörbahn analog zum ABR bis in den Hirnstamm erfasst und überwacht werden. Die ECochG kann die ABR Ableitung nicht gänzlich ersetzen, da ihre Verlässlichkeit bei elektrisch darstellbarer Beeinträchtigung der Hörbahn sinkt. Wann immer eine Welle V vorhanden ist, ist Monitoring mit der nicht-invasiven ECochG genauso gut möglich wie mit ABR. N2 - Introduction and goals: Monitoring of auditory brainstem responses (ABR) is a standard method during vestibular schwannoma surgery. As a farfield technique it bears some limitations. The goal of this study is to evaluate additional use of extra-tympanic electrocochleography (ECochG) as a nearfield technology. Methods: For this purpose electrophysiological monitoring data from 69 patients with vestibular schwannomas operated by the retrosigmoid approach between 2010 and 2014 were retrospectively evaluated and classified. ECochG was recorded simultaneously to ABR using an extra-tympanic ball electrode placed at the tympanum. Patient selection for this study was based on individual strong interest in hearing conserving surgery and independent of tumor extension (small to brainstem compressive) or hearing quality. The results were correlated with hearing quality before and after surgery. Results: Preoperative ABR and ECochG classes show a quite similar distribution and positive correlation with the preoperative hearing class. But, as expected, postoperative ECochG was less reliable than ABR in correlation with postoperative hearing quality: 25 of 43 patients with postoperative deafness showed an end-operative ECochG with a preserved cochlea potential. Recording of auditory function by non-invasive ECochG may be applied beyond the control of cochlea function. The identification of the later components (wave III and V) in ECochG is possible in the same way as with ABR. ECochG also provides significantly larger amplitudes. Analysis of ABR and ECochG classes identifies a very close positive correlation especially for classes 1 to 3, where wave V is still present. Conclusion: The significantly larger amplitudes of the ECochG allow shorter measurement times. This is especially useful in technically difficult phases during surgery. In addition to the cochlear function ECochG can be used for monitoring the auditory pathway down to the brain stem analogous to the ABR. ECochG cannot completely replace the ABR monitoring as its reliability decreases when electrical impairments occur. Whenever a wave V can be registered monitoring with the non-invasive ECochG is just as possible as with ABR. KW - Vestibularisschwannom KW - Akustikustumor KW - Elektrocochleographie KW - Akustisch evoziertes Potenzial KW - ABR KW - auditory brainstem responses KW - electrocochleography KW - Intraoperatives Monitoring KW - Neuromonitoring Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-216732 ER - TY - JOUR A1 - Otto, Christoph A1 - Kastner, Carolin A1 - Schmidt, Stefanie A1 - Uttinger, Konstantin A1 - Baluapuri, Apoorva A1 - Denk, Sarah A1 - Rosenfeldt, Mathias T. A1 - Rosenwald, Andreas A1 - Roehrig, Florian A1 - Ade, Carsten P. A1 - Schuelein-Voelk, Christina A1 - Diefenbacher, Markus E. A1 - Germer, Christoph-Thomas A1 - Wolf, Elmar A1 - Eilers, Martin A1 - Wiegering, Armin T1 - RNA polymerase I inhibition induces terminal differentiation, growth arrest, and vulnerability to senolytics in colorectal cancer cells JF - Molecular Oncology N2 - Ribosomal biogenesis and protein synthesis are deregulated in most cancers, suggesting that interfering with translation machinery may hold significant therapeutic potential. Here, we show that loss of the tumor suppressor adenomatous polyposis coli (APC), which constitutes the initiating event in the adenoma carcinoma sequence for colorectal cancer (CRC), induces the expression of RNA polymerase I (RNAPOL1) transcription machinery, and subsequently upregulates ribosomal DNA (rDNA) transcription. Targeting RNAPOL1 with a specific inhibitor, CX5461, disrupts nucleolar integrity, and induces a disbalance of ribosomal proteins. Surprisingly, CX5461-induced growth arrest is irreversible and exhibits features of senescence and terminal differentiation. Mechanistically, CX5461 promotes differentiation in an MYC-interacting zinc-finger protein 1 (MIZ1)- and retinoblastoma protein (Rb)-dependent manner. In addition, the inhibition of RNAPOL1 renders CRC cells vulnerable towards senolytic agents. We validated this therapeutic effect of CX5461 in murine- and patient-derived organoids, and in a xenograft mouse model. These results show that targeting ribosomal biogenesis together with targeting the consecutive, senescent phenotype using approved drugs is a new therapeutic approach, which can rapidly be transferred from bench to bedside. KW - CRC KW - CX5461 KW - MIZ1 KW - MYC KW - ribosome KW - RNAPOL1 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312806 VL - 16 IS - 15 ER - TY - JOUR A1 - Mechau, Jannik A1 - Frank, Andreas A1 - Bakirci, Ezgi A1 - Gumbel, Simon A1 - Jungst, Tomasz A1 - Giesa, Reiner A1 - Groll, Jürgen A1 - Dalton, Paul D. A1 - Schmidt, Hans‐Werner T1 - Hydrophilic (AB)\(_{n}\) Segmented Copolymers for Melt Extrusion‐Based Additive Manufacturing JF - Macromolecular Chemistry and Physics N2 - Several manufacturing technologies beneficially involve processing from the melt, including extrusion‐based printing, electrospinning, and electrohydrodynamic jetting. In this study, (AB)\(_{n}\) segmented copolymers are tailored for melt‐processing to form physically crosslinked hydrogels after swelling. The copolymers are composed of hydrophilic poly(ethylene glycol)‐based segments and hydrophobic bisurea segments, which form physical crosslinks via hydrogen bonds. The degree of polymerization was adjusted to match the melt viscosity to the different melt‐processing techniques. Using extrusion‐based printing, a width of approximately 260 µm is printed into 3D constructs, with excellent interlayer bonding at fiber junctions, due to hydrogen bonding between the layers. For melt electrospinning, much thinner fibers in the range of about 1–15 µm are obtained and produced in a typical nonwoven morphology. With melt electrowriting, fibers are deposited in a controlled way to well‐defined 3D constructs. In this case, multiple fiber layers fuse together enabling constructs with line width in the range of 70 to 160 µm. If exposed to water the printed constructs swell and form physically crosslinked hydrogels that slowly disintegrate, which is a feature for soluble inks within biofabrication strategies. In this context, cytotoxicity tests confirm the viability of cells and thus demonstrating biocompatibility of this class of copolymers. KW - 3D printing KW - (AB)\(_{n}\) segmented copolymers KW - biocompatibility KW - melt electrowriting Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224513 VL - 222 IS - 1 ER - TY - JOUR A1 - Schmidt, David A1 - Stolte, Matthias A1 - Süß, Jasmin A1 - Liess, Dr. Andreas A1 - Stepanenko, Vladimir A1 - Würthner, Frank T1 - Protein-like enwrapped perylene bisimide chromophore as bright microcrystalline emitter material JF - Angewandte Chemie International Edition N2 - Strongly emissive solid‐state materials are mandatory components for many emerging optoelectronic technologies, but fluorescence is often quenched in the solid state owing to strong intermolecular interactions. The design of new organic pigments, which retain their optical properties despite their high tendency to crystallize, could overcome such limitations. Herein, we show a new material with monomer‐like absorption and emission profiles as well as fluorescence quantum yields over 90 % in its crystalline solid state. The material was synthesized by attaching two bulky tris(4‐tert‐butylphenyl)phenoxy substituents at the perylene bisimide bay positions. These substituents direct a packing arrangement with full enwrapping of the chromophore and unidirectional chromophore alignment within the crystal lattice to afford optical properties that resemble those of their natural pigment counterparts, in which chromophores are rigidly embedded in protein environments. KW - cristal engeneering KW - dyes KW - flourescence quantum yield KW - perylene bisimides KW - solid-state emitters Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-204809 VL - 58 IS - 38 ER - TY - JOUR A1 - Wen, Lai A1 - Feil, Susanne A1 - Wolters, Markus A1 - Thunemann, Martin A1 - Regler, Frank A1 - Schmidt, Kjestine A1 - Friebe, Andreas A1 - Olbrich, Marcus A1 - Langer, Harald A1 - Gawaz, Meinrad A1 - de Wit, Cor A1 - Feil, Robert T1 - A shear-dependent NO-cGMP-cGKI cascade in platelets acts as an auto-regulatory brake of thrombosis JF - Nature Communications N2 - Mechanisms that limit thrombosis are poorly defined. One of the few known endogenous platelet inhibitors is nitric oxide (NO). NO activates NO sensitive guanylyl cyclase (NO-GC) in platelets, resulting in an increase of cyclic guanosine monophosphate (cGMP). Here we show, using cGMP sensor mice to study spatiotemporal dynamics of platelet cGMP, that NO-induced cGMP production in pre-activated platelets is strongly shear-dependent. We delineate a new mode of platelet-inhibitory mechanotransduction via shear-activated NO-GC followed by cGMP synthesis, activation of cGMP-dependent protein kinase I (cGKI), and suppression of Ca2+ signaling. Correlative profiling of cGMP dynamics and thrombus formation in vivo indicates that high cGMP concentrations in shear-exposed platelets at the thrombus periphery limit thrombosis, primarily through facilitation of thrombus dissolution. We propose that an increase in shear stress during thrombus growth activates the NO-cGMP-cGKI pathway, which acts as an auto-regulatory brake to prevent vessel occlusion, while preserving wound closure under low shear. KW - calcium signalling KW - fluorescence imaging KW - platelets KW - thrombosis Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-233616 VL - 9 ER -