@phdthesis{Irmisch2019,
  author    = {Irmisch, Linda},
  title     = {The role of septins and other regulatory proteins in abscission and midbody fate in C. elegans embryos},
  doi       = {10.25972/OPUS-18324},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-183244},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {Abscission marks the last step of cytokinesis and gives rise to two physically separated daughter cells and a midbody remnant. This work studies abscission by examining the extent of the abscission failure in C. elegans septin and ESCRT mutants with the help of the ZF1-degradation technique. The ZF1 technique is also applied to discern a possible role for PI3K during abscission. Lastly, we test the role of proteins required for macroautophagy but not for LC3-associated phagocytosis (LAP) and show that after release into the extracellular space, the midbody is resolved via LAP.},
  subject      = {Zellteilung},
  language  = {en}
}
@phdthesis{Kastner2019,
  author    = {Kastner, Carolin},
  title     = {LASP1 - ein neuer, phosphorylierungs-abh{\"a}ngiger Bindungspartner von CrkL in CML},
  doi       = {10.25972/OPUS-18753},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-187539},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {Das Verst{\"a}ndnis der molekularen Mechanismen, die einer malignen Erkrankung zugrunde liegen, ist der Schl{\"u}ssel zur Entwicklung zielgerichteter und effektiver therapeutischer M{\"o}glichkeiten. F{\"u}r das LIM und SH3 Dom{\"a}nen Protein 1, LASP1, konnte im Kontext zahl-reicher Tumorerkrankungen wie dem Mamma-Karzinom, dem Prostata-Karzinom oder dem Ovarial-Karzinom eine {\"U}berexpression ebenso wie eine Korrelation mit Aggressivit{\"a}t und Prognose der Tumorerkrankung gezeigt werden. Bisher war eine Relevanz von LASP1 jedoch nur f{\"u}r solide Tumorerkrankungen nachgewiesen worden. K{\"u}rzlich allerdings wurde lasp1 als eines von 6 Genen identifiziert, die eine exaktere Vorhersage von Krankheitsprogress und -rezidiv bei Patienten mit einer chronischen myeloischen Leuk{\"a}mie (CML) zulassen sollen. Zudem konnte, wie bereits bei zahlreichen anderen, soliden Tumorerkrankungen, eine signifikante {\"U}berexpression des lasp1-Gens in CML-Zellen nachgewiesen werden.Basierend auf diesen neuen Erkenntnissen besch{\"a}ftigte ich mich im Rahmen dieser Arbeit mit der Frage, welche Funktion LASP1 im Netz der einer CML zugrunde liegenden, molekularen Mechanismen {\"u}bernimmt. Mittels verschiedener Interaktionsassays konnte LASP1 als ein neuer, phosphorylierungs-abh{\"a}ngiger Bindungspartner von CrkL, dem wohl prominentesten Substrat der BCR-ABL-Kinase, identifiziert werden. Dabei impliziert das Attribut „phosphorylierungs-abh{\"a}ngig" sowohl den Phosphorylierungsstatus von LASP1 als auch des Interaktionspartners CrkL. Wie in Vorarbeiten gezeigt, stellt das Tyrosin 171 in der Aminos{\"a}urensequenz von LASP1 eine Phosphorylierungsstelle f{\"u}r die BCR-ABL-Kinase dar; mit LASP1 wurde somit auch ein neues Substrat dieser konstitutiv aktiven Tyrosinkinase entdeckt. Phosphoryliert an Tyrosin 171 kann LASP1 an die SH2-Dom{\"a}ne von CrkL, genauer an das FLVR-Motif innerhalb dieser, binden. Jedoch selbst an Tyrosin 207 durch die BCR-ABL-Kinase phosphoryliert, blockiert CrkL die eigene SH2-Dom{\"a}ne durch intramolekulare Wechselwirkungen f{\"u}r andere Protein-Protein-Interaktionen in gewissem Umfang. Diese neu gewonnenen Erkenntnisse liefern ein weiteres Puzzlest{\"u}ck zum Verst{\"a}ndnis des molekularen Netzwerks, das einer CML-Erkrankung zugrunde liegt und tragen so dazu bei, die Therapieoptionen dieser stetig zu verbessern.},
  subject      = {Chronisch-myeloische Leuk{\"a}mie},
  language  = {de}
}
@phdthesis{Heck2019,
  author    = {Heck, Johannes},
  title     = {Role of cyclase-associated protein 2 in platelet function and description of an inherited macrothrombocytopenia},
  doi       = {10.25972/OPUS-17996},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179968},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {Cyclase-associated protein (CAP)2 is an evolutionarily highly conserved actin-binding protein implicated in striated muscle development, carcinogenesis, and wound healing in mammals. To date, the presence as well as the putative role(s) of CAP2 in platelets, however, remain unknown. Therefore, mice constitutively lacking CAP2 (Cap2gt/gt mice) were examined for platelet function. These studies confirmed the presence of both mammalian CAP isoforms, CAP1 and CAP2, in platelets. CAP2-deficient platelets were slightly larger than WT controls and displayed increased GPIIbIIIa activation and P-selectin recruitment in response to the (hem)ITAM-specific agonists collagen-related peptide and rhodocytin. However, spreading of CAP2-deficient platelets on a fibrinogen matrix was unaltered. In conclusion, the functionally redundant CAP1 isoform may compensate for the lack of CAP2 in murine platelets. Moreover, the studies presented in this thesis unveiled a severe macrothrombocytopenia that occurred independently of the targeted Cap2 allele and which was preliminarily termed orphan (orph). Crossing of the respective mice to C57BL/6J wild-type animals revealed an autosomal recessive inheritance. Orph mice were anemic and developed splenomegaly as well as BM fibrosis, suggesting a general hematopoietic defect. Strikingly, BM MKs of orph mice demonstrated an aberrant morphology and appeared to release platelets ectopically into the BM cavity, thus pointing to defective thrombopoiesis as cause for the low platelet counts. Orph platelets exhibited marked activation defects and spread poorly on fibrinogen. The unaltered protein content strongly suggested a defective alpha-granule release to account for the observed hyporesponsiveness. In addition, the cytoskeleton of orph platelets was characterized by disorganized microtubules and accumulations of filamentous actin. However, further experiments are required to elucidate the activation defects and cytoskeletal abnormalities in orph platelets. Above all, the gene mutation responsible for the phenotype of orph mice needs to be determined by next-generation sequencing in order to shed light on the underlying genetic and mechanistic cause.},
  subject      = {Thrombozyt},
  language  = {en}
}
@phdthesis{Barnsteiner2019,
  author    = {Barnsteiner, Stefanie},
  title     = {CCR6 kontrolliert selektiv die Monozyten-vermittelte Entz{\"u}ndungsreaktion in der Atherosklerose},
  doi       = {10.25972/OPUS-17910},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179104},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {Der Chemokinrezeptor CCR6 wird von einer Vielzahl unterschiedener Zelltypen exprimiert, wie zum Beispiel Monozyten, Th17-Zellen und regulatorische T-Zellen, die im Zusammenhang mit der Entstehung von Atherosklerose stehen. Um die Bedeutung von CCR6 in der Pathogenese der Atherosklerose bestimmen zu k{\"o}nnen, wurden CCR6-defiziente (Ccr6-/- ) M{\"a}use mit low-density lipoprotein receptordefizienten (Ldlr-/-) M{\"a}usen gekreuzt, um Tiere zu erhalten, die anf{\"a}llig f{\"u}r Atherosklerose und zudem CCR6-defizient sind. Nach acht Wochen pro-atherogener, fettreicher western-type diet war die Auspr{\"a}gung der atherosklerotischen L{\"a}sionen im Aortensinus und der gesamten Aorta, sowie deren Gehalt an Plaquemakrophagen in den Ccr6-/-Ldlr-/- Tieren im Vergleich zu den Ldlr-/- Kontrolltieren signifikant vermindert. Die lokale und die systemische Verteilung von T-Zellen sowie die H{\"a}ufigkeit von Th1-, Th17-Zellen und regulatorischen T-Zellen blieb hingegen unver{\"a}ndert. Im Gegensatz dazu reduzierte sich die Zahl der im Blut zirkulierenden Gr-1high und Gr-1low Monozyten in den Ccr6-/-Ldlr-/- Tieren deutlich. Weiter konnte gezeigt werden, dass {\"u}ber CCR6 in vitro die Adh{\"a}sion von Monozyten an inflammatorisch ver{\"a}ndertem Endothel und in vivo die Adh{\"a}sion von Leukozyten an das Endothel der Karotiden vermittelt wird. Des Weiteren wurden in einem air pouch-Modell f{\"u}r akute Entz{\"u}ndungsreaktionen mittels CCR6 spezifisch Monozyten, aber keine TZellen rekrutiert. Summa summarum konnte die Bedeutung von CCR6 auf verschiedenen Ebenen der Pathogenese der Atherosklerose gezeigt werden: W{\"a}hrend CCR6 f{\"u}r die Hypercholesterin{\"a}mie assoziierte adaptive Immunantwort entbehrlich ist, reguliert es die Mobilisierung, Adh{\"a}sion und Rekrutierung von Monozyten und kontrolliert {\"u}ber diese Mechanismen die Akkumulation von Makrophagen und Genese atherosklerotischer L{\"a}sionen. CCR6 und sein Ligand CCL20 k{\"o}nnten somit vielversprechende Ziele neuer pharmakologischer Therapieans{\"a}tze sein, um auch die Atherogenese im Menschen zu unterbinden. Die Ergebnisse der Dissertation wurden im Dezember 2013 im Journal Thrombosis and Haematostasis unter dem Titel "CCR6 selectively promotes monocyte mediated inflammation and atherogenesis in mice" in geteilter Erstautorenschaft von Helga Manthey, Cl{\´e}ment Cochain und Stefanie Barnsteiner ver{\"o}ffentlicht (PMID: 24114205).},
  subject      = {Atherosklerose},
  language  = {de}
}
@article{SchuhmannKraftBieberetal.2019,
  author    = {Schuhmann, Michael K. and Kraft, Peter and Bieber, Michael and Kollikowski, Alexander M. and Schulze, Harald and Nieswandt, Bernhard and Pham, Mirko and Stegner, David and Stoll, Guido},
  title     = {Targeting platelet GPVI plus rt-PA administration but not α2β1-mediated collagen binding protects against ischemic brain damage in mice},
  series = {International Journal of Molecular Science},
  volume    = {20},
  journal   = {International Journal of Molecular Science},
  number    = {8},
  issn      = {1422-0067},
  doi       = {10.3390/ijms20082019},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201700},
  year      = {2019},
  abstract  = {Platelet collagen interactions at sites of vascular injuries predominantly involve glycoprotein VI (GPVI) and the integrin α2β1. Both proteins are primarily expressed on platelets and megakaryocytes whereas GPVI expression is also shown on endothelial and integrin α2β1 expression on epithelial cells. We recently showed that depletion of GPVI improves stroke outcome without increasing the risk of cerebral hemorrhage. Genetic variants associated with higher platelet surface integrin α2 (ITGA2) receptor levels have frequently been found to correlate with an increased risk of ischemic stroke in patients. However until now, no preclinical stroke study has addressed whether platelet integrin α2β1 contributes to the pathophysiology of ischemia/reperfusion (I/R) injury. Focal cerebral ischemia was induced in C57BL/6 and Itga2\(^{-/-}\) mice by a 60 min transient middle cerebral artery occlusion (tMCAO). Additionally, wild-type animals were pretreated with anti-GPVI antibody (JAQ1) or Fab fragments of a function blocking antibody against integrin α2β1 (LEN/B). In anti-GPVI treated animals, intravenous (IV) recombinant tissue plasminogen activator (rt-PA) treatment was applied immediately prior to reperfusion. Stroke outcome, including infarct size and neurological scoring was determined on day 1 after tMCAO. We demonstrate that targeting the integrin α2β1 (pharmacologic; genetic) did neither reduce stroke size nor improve functional outcome on day 1 after tMCAO. In contrast, depletion of platelet GPVI prior to stroke was safe and effective, even when combined with rt-PA treatment. Our results underscore that GPVI, but not ITGA2, is a promising and safe target in the setting of ischemic stroke.},
  language  = {en}
}
@article{StegnerKlausNieswandt2019,
  author    = {Stegner, David and Klaus, Vanessa and Nieswandt, Bernhard},
  title     = {Platelets as modulators of cerebral ischemia/reperfusion injury},
  series = {Frontiers in Immunology},
  volume    = {10},
  journal   = {Frontiers in Immunology},
  number    = {2505},
  issn      = {1664-3224},
  doi       = {10.3389/fimmu.2019.02505},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-195748},
  year      = {2019},
  abstract  = {Ischemic stroke is among the leading causes of disability and death worldwide. In acute ischemic stroke, the rapid recanalization of occluded cranial vessels is the primary therapeutic aim. However, experimental data (obtained using mostly the transient middle cerebral artery occlusion model) indicates that progressive stroke can still develop despite successful recanalization, a process termed "reperfusion injury." Mounting experimental evidence suggests that platelets and T cells contribute to cerebral ischemia/reperfusion injury, and ischemic stroke is increasingly considered a thrombo-inflammatory disease. The interaction of von Willebrand factor and its receptor on the platelet surface, glycoprotein Ib, as well as many activatory platelet receptors and platelet degranulation contribute to secondary infarct growth in this setting. In contrast, interference with GPIIb/IIIa-dependent platelet aggregation and thrombus formation does not improve the outcome of acute brain ischemia but dramatically increases the susceptibility to intracranial hemorrhage. Here, we summarize the current understanding of the mechanisms and the potential translational impact of platelet contributions to cerebral ischemia/reperfusion injury.},
  language  = {en}
}
@article{DeolLorenzStrieter2019,
  author    = {Deol, Kirandeep K. and Lorenz, Sonja and Strieter, Eric R.},
  title     = {Enzymatic logic of ubiquitin chain assembly},
  series = {Frontiers in Physiology},
  volume    = {10},
  journal   = {Frontiers in Physiology},
  number    = {835},
  doi       = {10.3389/fphys.2019.00835},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201731},
  year      = {2019},
  abstract  = {Protein ubiquitination impacts virtually every biochemical pathway in eukaryotic cells. The fate of a ubiquitinated protein is largely dictated by the type of ubiquitin modification with which it is decorated, including a large variety of polymeric chains. As a result, there have been intense efforts over the last two decades to dissect the molecular details underlying the synthesis of ubiquitin chains by ubiquitin-conjugating (E2) enzymes and ubiquitin ligases (E3s). In this review, we highlight these advances. We discuss the evidence in support of the alternative models of transferring one ubiquitin at a time to a growing substrate-linked chain (sequential addition model) versus transferring a pre-assembled ubiquitin chain (en bloc model) to a substrate. Against this backdrop, we outline emerging principles of chain assembly: multisite interactions, distinct mechanisms of chain initiation and elongation, optimal positioning of ubiquitin molecules that are ultimately conjugated to each other, and substrate-assisted catalysis. Understanding the enzymatic logic of ubiquitin chain assembly has important biomedical implications, as the misregulation of many E2s and E3s and associated perturbations in ubiquitin chain formation contribute to human disease. The resurgent interest in bifunctional small molecules targeting pathogenic proteins to specific E3s for polyubiquitination and subsequent degradation provides an additional incentive to define the mechanisms responsible for efficient and specific chain synthesis and harness them for therapeutic benefit.},
  language  = {en}
}