Muscle formation is a coordinated process driven by extensive gene expression changes where single cells fuse together to form multinucleated muscle fibers. Newly synthesized mRNAs are then... Show moreMuscle formation is a coordinated process driven by extensive gene expression changes where single cells fuse together to form multinucleated muscle fibers. Newly synthesized mRNAs are then regulated by RNA binding proteins (RBPs), affecting post-transcriptional transcript metabolism. Here, we determined how large-scale gene expression changes affect the catalog of RBPs by studying proliferating and differentiated muscle cells in healthy and dystrophic conditions. Transcriptomic analysis showed that the expression of more than 7000 genes was affected during myogenesis. We identified 769 RBPs, of which 294 were muscle-specific and 49 were uniquely shared with cardiomyocytes. A subset of 32 RBPs (half of which were muscle-specific) was found to be preferentially associated with target mRNAs in either myoblasts (MBs) or myotubes (MTs). A large proportion of catalytic proteins were bound to mRNAs even though they lack classical RNA binding domains. Finally, we showed how the identification of cell-specific RBPs enabled the identification of biomarkers that can separate healthy individuals from dystrophic patients. Our data show how interactome data can shed light on new basic RNA biology as well as provide cell-specific data that can be used for diagnostic purposes. Show less
14q32 microRNAs are known to play a role in various forms of vascular remodelling. This thesis elucidated that snoRNAs of the 14q32 locus are also involved in vascular remodelling processes. The... Show more14q32 microRNAs are known to play a role in various forms of vascular remodelling. This thesis elucidated that snoRNAs of the 14q32 locus are also involved in vascular remodelling processes. The expression of both noncoding RNA types in the human vasculature has been found to be vascular location and vessel type specific and are therefore promising targets for future implementation in clinical practice.The second part of this thesis focuses on three different types of 14q32 microRNA expression regulation in order to affect various vascular remodelling processes. 14q32 DNA methylation, myostatin and CIRBP were tested for their effect on 14q32 microRNA expression and the (subsequent) effect on vein graft disease and tissue ischemia, restenosis and angiogenesis, respectively. DNA methylation is not correlated with 14q32 microRNA expression, but directly interacts with vascular remodelling process status. Myostatin negatively affects 14q32 microRNA expression in vascular smooth muscle cells, but not in inflammatory cells involved in restenosis. Due to this latter finding, overall restenosis was not inhibited by myostatin. Inhibition of CIRBP inhibited 14q32 microRNA expression post-transcriptionally and therefore increased in vitro angiogenesis. These promising findings provide novel indirect regulators of vascular remodelling processes and future research will elucidate the potential for clinical application. Show less
