@phdthesis{Busch2021,
  author    = {Busch, Albert Franz Jakob},
  title     = {Modification of angiogenesis to abrogate abdominal aortic aneurysm growth},
  doi       = {10.25972/OPUS-24135},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-241356},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {Introduction: Abdominal aortic aneurysm (AAA) is a pathological saccular enlargement most often of the infrarenal aorta. Eventual rupture is fatal, making preemptive surgical therapy upon a diameter threshold of >50mm the treatment of choice. The pathophysiology, especially the initial trigger aortic remodeling is still largely unknown. However, some characteristic features involved in aneurysm growth have been established, such as medial angiogenesis, low-grade inflammation, vascular smooth muscle cell (VSMC) phenotype switch, extracellular remodeling, altered hemodynamics and an eventual humoral immune answer. Currently, no medical treatment options are available. RNA therapeutics and drug repurposing offer new possibilities to overcome this shortage. Using such to target angiogenesis in the aneurysm wall and investigate their potential mechanisms is the aim of this thesis. Material and Methods: We test our hypothesis by targeting the long non-coding RNA H19 and re-use the anti-cancer drug Lenvatinib in two murine inducible AAA models and one preclinical large animal model in the LDLR-/- pig. Furthermore, a H19-/- mouse is included to verify the results. AAA and control samples from a human biobank along with a primary human cell culture are used to verify results ex vivo by qPCR, WesternBlot, live cell imaging, histo- and immunohistochemistry along with gene array analysis, RNA knockdown, pull-down- and promotor assays. Results: H19 is significantly upregulated in AAA mice models and its knockdown limited aneurysm growth. It is well known that H19 interacts with several transcription factors. We found that cytoplasmic interaction between H19 and hypoxia-inducible factor 1-alpha (HIF1α) increased apoptosis in cultured SMCs associated with sequential p53 stabilization. In contrast, the knockdown of H19 was associated with markedly decreased apoptotic cell rates. Our data underline that HIF1α was essential in mediating the pro-apoptotic effects of H19. Secondly, Lenvatinib was applied both systemically and locally by endovascular means in mice with an established AAA. The drug significantly halted aneurysm growth and array analysis revealed myosin heavy chain 11 (MYH11) as the most differentially regulated target. This was shown to be up regulated after Lenvatinib treatment of primary AAA smooth muscle cells suggesting a salvage mechanism to obtain a contractile phenotype based on gene expression and immunohistochemistry. The same results were shown upon a local endovascular Lenvatinib-coated balloon angioplasty in the established aneurysmatic lesion of a novel atherosclerotic LDLR-/- Yucatan minipig model. Decreased phosphorylation of extracellular-signal regulated kinases 1-2 (ERK1-2) is the downstream effect of Lenvatinib-specific blockage of the vascular endothelial growth factor receptor (VEGFR2). Conclusion: Taking into account the heterogeneity of the disease, inhibition of VSMC phenotype switch, extracellular remodeling and angiogenesis seem promising targets in some if not all AAA patients. Together with surveillance and surgical therapy, these new non-invasive treatment strategies would allow for a more personalized approach to treat this disease.},
  subject      = {Aortenaneurysma},
  language  = {en}
}
@phdthesis{Busch2011,
  author    = {Busch, Albert Franz Jakob},
  title     = {Pr{\"a}lamin A und Progerie - verursachende Mutanten im Kontext nukle{\"a}rer Transportprozesse, der Kernlaminaintegrit{\"a}t und CaaX - Prozessierung},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-71662},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Zur Charakterisierung nukle{\"a}rer Proteinexportvorg{\"a}nge wurde in dieser Arbeit zum ersten Mal ein System heterodimerisierender Fusionsproteine auf Basis des kommerziell verf{\"u}gbaren ARGENT™ Regulated Heterodimerization Kit 2.0 von ARIAD verwendet. Die Expressionsvektoren wurden so ver{\"a}ndert, dass ein CRM1 - vermittelter Proteinexport {\"u}ber die Zellkernh{\"u}lle mittels Fluoreszenzmikroskopie in HeLa - Zellen und humanen Fibroblasten live oder nach Fixation dargestellt werden konnte. Der Export folgte in HeLa - zellen einer exponentiellen Kinetik, FN/C - Bestimmungen zwischen Wildtyp - und RD (Restriktive Dermopathie) - Fibroblasten ergaben keinen Unterschied im Proteinexport. Eine Inhibition der initialen CaaX - Prozessierung von trunkiertem Pr{\"a}lamin A (head/rod) durch Mevinolin ergab keine signifikante Akkumulationsver{\"a}nderung des trunkierten Pr{\"a}lamins im Zellkern. Erg{\"a}nzende subzellul{\"a}re Lokalisationsstudien unter Zuhilfenahme ausgew{\"a}hlter CaaX - Mutanten, um die gezeigte Unabh{\"a}ngigkeit der CaaX - Prozessierung zu verifizieren, stehen noch aus. FRAP - Untersuchungen in HeLa - Zellen zeigten f{\"u}r die episomal exprimierten trunkierten Fusionsproteine DsRed - Pr{\"a}lamin A Δ50 und DsRed - Pr{\"a}lamin A Δ90 keinen Unterschied in der lateralen Mobilit{\"a}t. Gegen{\"u}ber dem Wildtyp - DsRed - Pr{\"a}lamin A ist die Beweglichkeit jedoch signifikant reduziert. Bei der Applikation von thermischem Stress (37°C - 51°C) auf Pr{\"a}lamin A, Pr{\"a}lamin A Δ50 oder Pr{\"a}lamin A Δ90 exprimierende HeLa - Zellen, konnte keine Ver{\"a}nderung hinsichtlich der subzellul{\"a}ren Verteilung des zus{\"a}tzlich koexprimierten Markerproteins GFP - ß - Galaktosidase im Sinne nukle{\"a}ren Schrankenst{\"o}rung festgestellt werden. Somit scheint die Kernh{\"u}lle trotz der zu Zellkerndysmorphien und KPK - Fehllokalisationen f{\"u}hrenden Pr{\"a}lamin A - Mutanten hinsichtlich ihrer Schrankenfunktion intakt zu bleiben.},
  subject      = {Progeria infantilum},
  language  = {de}
}