Identification of novel Wnt/PCP signaling regulators and their role in midbrain dopaminergic neuron development and Parkinson's disease

Wnt signaling controls a wide spectrum of complex cell responses during prenatal development, in the adulthood and during disease. In this doctoral study, we have identified and explored novel regulatory components of Wnt/Planar Cell Polarity (PCP) pathway and their function in various cellular processes during embryogenesis and central nervous system (CNS) development. We paid special attention to molecular mechanisms underlying the morphogenesis of the ventral midbrain (VM) and development of midbrain dopaminergic (mDA) neurons, a brain area that is strictly regulated by Wnt signaling. We also touched upon possible clinical applications of our findings in neurodegenerative disorders, such as Parkinson's disease (PD). We used a large number of traditional biochemical tools as well as more advanced methodologies such as proteomics and phospho-proteomics, RNA-scope in situ hybridization, confocal microscopy, electron microscopy and CRISPR/Cas9 technology (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated protein 9). We have also used different models such as cell lines and primary cultures, as well as genetically modified organisms, including Xenopus laevis (Frog), Danio rerio (zebrafish) and mouse embryos. To better understand the functional complexity of the Wnt/PCP signaling, we examined a number of transgenic mice models, which allowed us to uncover the function of Wnt/PCP protein complexes in the mammalian CNS. Finally, some of our observations were confirmed by using human prenatal brain tissue (study II). Please find below the main highlights of each study included in this thesis. In study I, we explored the molecular mechanism by which the crucial Wnt signaling integrator Dvl and the cell cycle protein kinase NEK2 regulate the progression of cells from the G2 to the M phase. We identified Dvl as a NEK2 substrate and described that they mediate disassembling of centrosomal linker proteins from the centrosome, a process essential for duplicating the centrioles and polarization of ...