@phdthesis{Laesker2023, author = {L{\"a}sker, Katharina}, title = {The influence of the short-chain fatty acid butyrate on "Signal transducer and activator of transcription 3" (STAT3) and selected inflammatory genes in the colon carcinoma cell line CACO-2 cultured in 2D and 3D}, doi = {10.25972/OPUS-30038}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300389}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {A disturbance in the symbiotic mutualism between the intestinal microbiome and the human host's organism (syn. dysbiosis) accompanies the development of a variety of inflammatory and metabolic diseases that comprise the Metabolic Syndrome, chronic inflammatory gut diseases like Crohn's disease, Non-alcoholic fatty liver disease (NAFLD) and cardiovascular diseases, among others. The changed uptake and effectiveness of short chain fatty acids (SCFAs) as well as an increase of the intestinal permeability are common, interdependent disease elements in this regard. Short chain fatty acids are end-products of intestinal bacterial fermentation and affect the mucosal barrier integrity via numerous molecular mechanisms. There is evidence to suggest, that SCFAs have a modulating influence on Signal transducer and activator of transcription 3 (STAT3) in intestinal epithelial cells. STAT3 is a central gene-transcription factor in signaling pathways of proliferation and inflammation. It can be activated by growth factors and other intercellular signaling molecules like the cytokine Oncostatin M (OSM). The mode of STAT3's activation exhibits, finally, a decisive influence on the immunological balance at the intestinal mucosa. Therefore, the posttranslational modification of STAT3 under the influence of SCFAs is likely to be a very important factor within the development and -progression of dysbiosis-associated diseases. In this study, a clear positive in vitro-effect of the short chain fatty acid butyrate on the posttranslational serine727-phosphorylation of STAT3 and its total protein amount in the human adenocarcinoma cell line CACO2 is verified. Moreover, an increased gene expression of the OSM-receptor subunit OSMRβ can be observed after butyrate incubation. Histone deacetylase inhibition is shown to have a predominant role in these effects. Furthermore, a subsequent p38 MAPK-activation by Butyrate is found to be a key molecular mechanism regarding the STAT3-phosphorylation at serine727-residues. To consider the portion of butyrate receptor signaling in this context in future assays, a CACO-2 cell 3D-culture model is introduced in which an improvement of the GPR109A-receptor expression in CACO-2 cells is accomplished.}, subject = {Butyrate }, language = {en} } @article{SchramaUgurelSuckeretal.2014, author = {Schrama, David and Ugurel, Selma and Sucker, Antje and Ritter, Cathrin and Zapatka, Marc and Schadendorf, Dirk and Becker, J{\"u}rgen Christian}, title = {STAT3 Single Nucleotide Polymorphism rs4796793 SNP Does Not Correlate with Response to Adjuvant IFNα Therapy in Stage III Melanoma Patients}, series = {Frontiers in Medicine}, volume = {1}, journal = {Frontiers in Medicine}, number = {47}, issn = {2296-858X}, doi = {10.3389/fmed.2014.00047}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120602}, year = {2014}, abstract = {Interferon alpha (IFNα) is approved for adjuvant treatment of stage III melanoma in Europe and the US. Its clinical efficacy, however, is restricted to a subpopulation of patients while side effects occur in most of treated patients. Thus, the identification of predictive biomarkers would be highly beneficial to improve the benefit to risk ratio. In this regard, STAT3 is important for signaling of the IFNα receptor. Moreover, the STAT3 single-nucleotide polymorphism (SNP) rs4796793 has recently been reported to be associated with IFNα sensitivity in metastatic renal cell carcinoma. To translate this notion to melanoma, we scrutinized the impact of rs4796793 functionally and clinically in this cancer. Interestingly, melanoma cells carrying the minor allele of rs4796793 were the most sensitive to IFNα in vitro. However, we did not detect a correlation between SNP genotype and STAT3 mRNA expression for either melanoma cells or for peripheral blood lymphocytes. Next, we analyzed the impact of rs4796793 on the clinical outcome of 259 stage III melanoma patients of which one-third had received adjuvant IFNα treatment. These analyses did not reveal a significant association between the STAT3 rs4796793 SNP and patients' progression free or overall survival when IFNα treated and untreated patients were compared. In conclusion, STAT3 rs4796793 SNP is no predictive marker for the efficacy of adjuvant IFNα treatment in melanoma patients.}, language = {en} } @phdthesis{ThangarajSelvaraj2013, author = {Thangaraj Selvaraj, Bhuvaneish}, title = {Role of CNTF-STAT3 signaling for microtubule dynamics inaxon growth and maintenance: Implications in motoneuron diseases}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-76889}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2013}, abstract = {Neurotrophic factor signaling modulates differentiation, axon growth and maintenance, synaptic plasticity and regeneration of neurons after injury. Ciliary neurotrophic factor (CNTF), a Schwann cell derived neurotrophic factor, has an exclusive role in axon maintenance, sprouting and synaptic preservation. CNTF, but not GDNF, has been shown to alleviate motoneuron degeneration in pmn mutant mice carrying a missense mutation in Tbce gene, a model for Amyotrophic Lateral Sclerosis (ALS). This current study elucidates the distinct signaling mechanism by which CNTF rescues the axonal degeneration in pmn mutant mice. ...}, subject = {Ciliary neurotrophic factor}, language = {en} } @phdthesis{Wagner2007, author = {Wagner, Toni}, title = {Activity and Crosstalk of STAT3 and BMP Signalling Pathways in Pluripotency Control of Mouse and Medaka Stem Cells}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-26495}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2007}, abstract = {- 77/83 allerdings inaktiv in Kulturen und Embryonen von Medaka. Dieser Unterschied wird durch Daten aus humanen ES-Zellkulturen unterst{\"u}tzt. Letztere sind ebenfalls komplett STAT3 unabh{\"a}ngig. Die BMP-Smad Kaskade wiederum ist in Medaka-Stammzellen aktiv, Antidifferenzierungsgene wie id2, die durch BMP direkt kontrolliert werden, sind dementsprechend exprimiert. Diese Daten stimmen wiederum mit dem Maussystem {\"u}berein, w{\"a}hrend humane ES-Zellen diesbez{\"u}glich bislang nicht untersucht wurden. Die Interaktion zwischen verschiedenen Signalwegen ist ein bisher noch nicht gut verstandenes Gebiet. Die Integration verschiedener Signale ist aber speziell f{\"u}r Stammzellen, die ihr Differenzierungsschicksal von winzigen Abweichungen in der Signalmixtur abh{\"a}ngig machen, von entscheidender Bedeutung. Im zweiten Teil der hier vorgelegten Arbeit konnte eine Interaktion zwischen dem BMP-Rezeptor 1a und STAT3 nachgewiesen werden. Diese Interaktion ist offenbar Teil eines variablen Komplexes. Zum ersten Mal war es auch m{\"o}glich, funktionale Konsequenzen f{\"u}r STAT3 nach Stimulierung des BMP-Rezeptors 1a zu dokumentieren. Nach Belegung des BMP-Rezeptors 1a mit dem mutierten BMP2-A34D wird STAT3 trotz Aktivierung durch Phosphorylierung an Tyrosin 705 im Zytoplasma von Maus Stammzellen festgehalten. Zusammengenommen konnte hier gezeigt werden, dass eine Interaktion zwischen den bislang als isoliert betrachteten Signalwegen BMP-Smad und STAT3 besteht. Des Weiteren wurde das Medaka-Stammzellkultursystem benutzt, um zu zeigen, dass STAT3 f{\"u}r die Pluripotenz von Stammzellen nur im Maussystem eine Rolle spielt, wohingegen BMPZielgene wie id2 in bislang allen getesteten ES-Zellkultursystemen aktiv sind.}, subject = {Stammzellen}, language = {en} }