Title Promoter Affiliations Abstract "MOR(e) partners in crime: a bioassay approach to study µ-opioid receptor dimerization by new synthetic opioids" "Christophe Stove" "Department of Bio-analysis" "Since 2009, over 73 new synthetic opioids (NSO) have emerged on the global drug market as reported by the European Monitoring Centre for Drugs and Drug Addiction, rendering this one of the fastest growing groups of New Psychoactive Substances. The very high potency, combined with the high risk of fatal overdoses due to respiratory depression, of NSO poses a serious threat to public health. Since relatively little is known about the pharmacology and toxicology of many newly emerging NSO, further insight into NSO pharmacology will result in improved assessment of harm potential and better understanding of the mechanism of action of opioids in general. This project aims at investigating the hitherto less explored concept of μ-opioid receptor (MOR) di- or multimerization. More specifically, based on the recent findings in the Lab that a class of NSO induces MOR dimerization, this project will study in-depth the molecular mechanism behind this observation. To achieve this, an optimized MOR-MOR interaction assay will be developed, which will be used for structure-activity relationship determination, using a panel of structural analogues of existing NSO. In addition, selected NSO will be pharmacologically evaluated in vivo. The structural basis and mechanism of MOR dimerization will be further elucidated via modelling of MOR and MOR/MOR dimers, combined with the generation of MOR mutants. Additionally, a biosensor capable of assessing wild type MOR-MOR interaction will be developed." "New therapeutic targets in the dimerization modes that drive androgen receptor functioning" "Frank Claessens" "Laboratory of Molecular Endocrinology" "The androgen receptor (AR) is a ligand-inducible transcription factor. It has three domains: an aminoterminal domain (NTD), a central DNA-binding domain (DBD), and a C-terminal ligand-binding domain (LBD). Like many transcription factors, the AR has to dimerise in order to find the DNA response elements in the genome. However, the AR has three independent dimerization mechanisms: via the DBD, via the LBD, and via so-called N/C interactions. In vitro studies resulted in inconclusive and apparent contradictory observations. We therefore first investigate the in vivo role of each of these dimerizations by analyzing the effects of loss of function mutations in rodent models. The in vivo data are a starting point to inspire further in vitro analysis in cell lines at the level of gene expression control and chromatin binding, as well as further biophysical approaches and structural studies. For the LBD dimerization, this will include studying the effects of small molecule inhibitors. Ultimately, this basic research project will deliver new insights in AR molecular biology which will be translatable in applications that target the AR during the treatment of advanced lethal forms of prostate cancer" "MOR(e) partners in crime: a bioassay approach to study μ-opioid receptor dimerization by new synthetic opioids" "Christophe Stove" "Department of Bio-analysis" "The emergence of new synthetic opioids (NSO) poses a serious threat to public health. This project aims at investigating the concept of μ-opioid receptor (MOR) dimerization, based on recent findings that a class of NSO induces MOR dimerization. An optimized MOR-MOR interaction assay will be developed, and the mechanisms of MOR dimerization will be elucidated via modelling of MOR dimers." "New therapeutic targets in the dimerization modes that drive androgen receptor functioning" "Frank Claessens" "Laboratory of Molecular Endocrinology" "The androgen receptor (AR) is a ligand-inducible transcription factor. It has three domains: an aminoterminal domain (NTD), a central DNA-binding domain (DBD), and a C-terminal ligand-binding domain (LBD). Like many transcription factors, the AR has to dimerise in order to find the DNA response elements in the genome. However, the AR has three independent dimerization mechanisms: via the DBD, via the LBD, and via so-called N/C interactions. In vitro studies resulted in inconclusive and apparent contradictory observations. We therefore first investigate the in vivo role of each of these dimerizations by analyzing the effects of loss of function mutations in rodent models. The in vivo data are a starting point to inspire further in vitro analysis in cell lines at the level of gene expression control and chromatin binding, as well as further biophysical approaches and structural studies. For the LBD dimerization, this will include studying the effects of small molecule inhibitors.  Ultimately, this basic research project will deliver new insights in AR molecular biology which will be translatable in applications that target the AR during the treatment of advanced lethal forms of prostate cancer." "GPCR dimerization in AD: From brain expression to therapeutic potential." "Neurochemistry and behaviour" "GPCR targets are considered highly ""druggable"" and a growing interest in GPCRs forming hetero- or homodimers as possible newpharmacological targets in a variety of diseases, including AD and related dementias, has been expressed. The translation ofGPCR heterodimers and mosaics to pharmaceutical drug discovery and development is however in its infancy and hampered bythe lack of appropriate tools to study these bioconjugates, as well as insufficient understanding of which interactions are importantand (patho)physiologically relevant. This project will provide a systematic screening of GPCR expression and subcellularlocalisation in human brain tissue, as well as in a valid amyloidosis mouse model. Latter model will be applied to provide the veryfirst proof-of-concept that targeting an AD-relevant GPCR heterodimer with a bivalent ligand may provide a novel therapeuticapproach that could cause a major shift in AD treatment." "Molecular biology of the dimerization functions of the androgen receptor" "Frank Claessens" "Laboratory of Molecular Endocrinology" "The androgen receptor (AR: NR3C4) is a transcription factor which plays a central role in the development and maintenance of the male phenotype. This is illustrated by the many AR mutations that have been described in androgen insensitivity syndrome patients. While most of these mutations affect known AR functions like ligand, DNA or co-activator binding, some remained unexplained. We recently described a detailed map of the dimerization interface of the ligandbinding domain (LBD) in which over 40 of these formerly unexplained mutations are situated. The here presented project aims to define the in vivo implications of LBD dimer-disrupting mutations. We will develop the first rodent model in which a specific function of the AR can be knocked in, in an inducible way. This will allow the in vivo study of the impact of the mutation on transcription in adult tissues. There are three ways in which the AR can dimerize: via the DNA-binding domain, via interactions between the amino- and carboxyterminal domains and via this LBD surface. The second work package will use STARRseq methodology to define the role of each of these three interfaces during AR transactivation and DNA recognition. Ultimately, we will integrate the data from the in vivo and in vitro work to link receptor dimerization modes with tissue-specific AR functioning at the chromatine level." "What is the role of recepter dimerization in androgen action?" "Frank Claessens" "Laboratory of Cellular Metabolism and Metabolic Regulation (VIB-KU Leuven), Laboratory of Molecular Endocrinology" "Mutations in the androgen receptor found in androgen insensitivity syndrome (AIS) patients provide a wealth of information on the molecular biology of this receptor. Most recently, we described how the ligand-binding domain of the androgen receptor dimerises. The importance of this dimerization is illustrated by the fact that many mutations which are correlated with AIS are predicted to disrupt this interface. To study this further, we will first develop a mouse model mimicking a dimerization mutation found in two siblings with AIS. In vitro, this mutation indeed disrupts dimerization without affecting ligand binding or receptor stability. The main question here is where the phenotype of this mouse model fits in the AIS spectrum between mild male infertility and complete AIS. During my PhD, I will also determine the effect of the dimer mutations on the transactivation process in cellular models by the state-of-the-art methodologies STARR-seq and CRISPR/Cas9. This will help identify the contribution of receptor dimerization in the transcription activation process. In the long run, a more detailed knowledge on androgen receptor functioning can guide the development of therapeutic strategies that inhibit or activate the androgen receptor in much more selective ways." "Structural insights into the cis/trans dimerization of human DSCAM" "Rob Meijers, Dietmar Schmucker" "Neuronal Wiring Lab (VIB-KU Leuven)" "Down Syndrome Cell Adhesion Molecule (DSCAM) belongs to the immunoglobulin (Ig) superfamily of cell-surface receptors and is implicated in cell adhesion and neuronal wiring. The Drosophila Dscam gene can give rise to more than 19,000 distinct ectodomain isoforms through differential splicing in three Ig domains, Ig2, Ig3, and Ig7. The diversity is used to generate a repertoire of homophilic interaction partners, exclusively amongst identical isoforms. This high degree of specificity in homophilic recognition is a key regulator of neurite self-avoidance in arthropods. The human genome contains two DSCAM genes (DSCAM and DSCAM-Like1), which do not undergo extensive alternative splicing. Nevertheless, Dscam and DSCAM share similar biological roles. Using X-ray crystallography, electron microscopy, and small-angle X-ray scattering, we have performed structural studies on human DSCAM to investigate whether homophilic dimerization is conserved between the species. Complementary binding and biophysical studies combined with site-directed mutagenesis suggest a possible mechanism for cis/trans dimerization, wherein the Ig7 domain plays a pivotal role." "Generation and detailed analysis of novel tools to study the importance of dimerization of the Glucocorticoid Receptor in inflammation." "Claude Libert" "Department of Biomedical molecular biology" "Novel tools to study the importance of dimerization of the GR wil be generated and investigated. Cells and mice will be generated with inducible GR dimerization and these will be used to study the role of GR dimerization in the control of SIRS." "Generation and detailed analysis of novel tools to study the importance of dimerization of the Glucocorticoid Receptor in inflammation. " "Claude Libert" "Department of Biomedical molecular biology" "Since Systemic Inflammatory Response Syndrome (SIRS), such as sepsis, is by definition an inflammatory disease, it is bizarre that Glucocorticoids (GCs) are ineffective in this context. To generate more effective GCs, over the past 25 years, the emphasis has been on the generation of GR ligands that favor GR monomer formation (referred to as SElective GR Agonists, SEGRAs). This has not resulted in a successful therapy. Our observations indicate that, at least for the treatment of SIRS, we should go in the opposite direction by generating SElective DImerizing GR Agonists (= SEDIGRAs). To be able to do this, it is also necessary to understand the process of GR dimerization and to study what will be the impact of increasing the ratio of GR dimers/GR monomers in cells and in animals. In this project, we will generate and analyze novel tools to study the importance of dimerization of the GR in inflammation. A system by which we can control the ratio of GR dimers/GR monomers will be created based on the iDIMERIZE system. The effect of different degrees of GR dimerization will be tested in vitro. Based on the same system, we will generate mice with chemically inducible GR dimerization (GRcid) by the use of the CRISPR/Cas9 technology. Because we are interested in acute inflammation, we will study these mice in SIRS models. These mice will be phenotyped and the hope is that the chemically induced GR dimerization in combination with GCs will lead to a complete control of SIRS. "