@phdthesis{Schul2013, author = {Schul, Daniela}, title = {Spatio-temporal investigation and quantitative analysis of the BMP signaling pathway}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-84224}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2013}, abstract = {Bone Morphogenetic Proteins (BMPs) are key regulators for a lot of diverse cellular processes. During embryonic development these proteins act as morphogens and play a crucial role particularly in organogenesis. BMPs have a direct impact on distinct cellular fates by means of concentration-gradients in the developing embryos. Using the diverse signaling input information within the embryo due to the gradient, the cells transduce the varying extracellular information into distinct gene expression profiles and cell fate decisions. Furthermore, BMP proteins bear important functions in adult organisms like tissue homeostasis or regeneration. In contrast to TGF-ß signaling, currently only little is known about how cells decode and quantify incoming BMP signals. There is poor knowledge about the quantitative relationships between signal input, transducing molecules, their states and location, and finally their ability to incorporate graded systemic inputs and produce qualitative responses. A key requirement for efficient pathway modulation is the complete comprehension of this signaling network on a quantitative level as the BMP signaling pathway, just like many other signaling pathways, is a major target for medicative interference. I therefore at first studied the subcellular distribution of Smad1, which is the main signal transducing protein of the BMP signaling pathway, in a quantitative manner and in response to various types and levels of stimuli in murine c2c12 cells. Results indicate that the subcellular localization of Smad1 is not dependent on the initial BMP input. Surprisingly, only the phospho-Smad1 level is proportionally associated to ligand concentration. Furthermore, the activated transducer proteins were entirely located in the nucleus. Besides the subcellular localization of Smad1, I have analyzed the gene expression profile induced by BMP signaling. Therefore, I examined two endogenous immediate early BMP targets as well as the expression of the stably transgenic Gaussia Luciferase. Interestingly, the results of these independent experimental setups and read-outs suggest oscillating target gene expression. The amplitudes of the oscillations showed a precise concentration-dependence for continuous and transient stimulation. Additionally, even short-time stimulation of 15' activates oscillating gene-expression pulses that are detectable for at least 30h post-stimulation. Only treatment with a BMP type I receptor kinase inhibitor leads to the complete abolishment of the target gene expression. This indicated that target gene expression oscillations depend directly on BMP type I receptor kinase activity.}, subject = {Knochen-Morphogenese-Proteine}, language = {en} } @article{DrozdSaenkoBrenneretal.2015, author = {Drozd, Valentina M. and Saenko, Vladimir A. and Brenner, Alina V. and Drozdovitch, Vladimir and Pashkevich, Vasilii I. and Kudelsky, Anatoliy V. and Demidchik, Yuri E. and Branovan, Igor and Shiglik, Nikolay}, title = {Major Factors Affecting Incidence of Childhood Thyroid Cancer in Belarus after the Chernobyl Accident: Do Nitrates in Drinking Water Play a Role?}, series = {PLoS One}, volume = {10}, journal = {PLoS One}, number = {9}, doi = {10.1371/journal.pone.0137226}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-141863}, pages = {e0137226}, year = {2015}, abstract = {One of the major health consequences of the Chernobyl Nuclear Power Plant accident in 1986 was a dramatic increase in incidence of thyroid cancer among those who were aged less than 18 years at the time of the accident. This increase has been directly linked in several analytic epidemiological studies to iodine-131 (I-131) thyroid doses received from the accident. However, there remains limited understanding of factors that modify the I-131-related risk. Focusing on post-Chernobyl pediatric thyroid cancer in Belarus, we reviewed evidence of the effects of radiation, thyroid screening, and iodine deficiency on regional differences in incidence rates of thyroid cancer. We also reviewed current evidence on content of nitrate in groundwater and thyroid cancer risk drawing attention to high levels of nitrates in open well water in several contaminated regions of Belarus, i.e. Gomel and Brest, related to the usage of nitrogen fertilizers. In this hypothesis generating study, based on ecological data and biological plausibility, we suggest that nitrate pollution may modify the radiation-related risk of thyroid cancer contributing to regional differences in rates of pediatric thyroid cancer in Belarus. Analytic epidemiological studies designed to evaluate joint effect of nitrate content in groundwater and radiation present a promising avenue of research and may provide useful insights into etiology of thyroid cancer.}, language = {en} }