Structure-based drug discovery approaches to identify modulators of the Nrf2 pathway and glutamate receptors AMPA GluA2 and Kainate GluK1 and GluK2

Nrf2 project: The protein nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that provides protection against oxidative stress and the dysfunction of this pathway has been suggested to be implicated in many neurodegenerative diseases. The aim of this thesis was to identify novel Nrf2 activators that disrupt the protein-protein interaction between Nrf2 and Keap1 and thereby induce increased expression of antioxidant enzymes and protective genes. The crystal structure of the Keap1-Nrf2 interface was used to perform a virtual screen and compounds from the screen were assayed using a cellular nuclear complementation assay that measures the nuclear translocation of Nrf2 from the cytosol. Although two novel compounds were found to increase the Nrf2 nuclear translocation, they had low activity and further characterisation did not provide sufficient evidence of a Nrf2-Keap1 robust interaction. iGluRs project: AMPA and kainate receptors are ionotropic glutamate receptors (iGluRs) that are important for excitatory transmission and synaptic plasticity and are linked to several neurological disorders such as epilepsy, schizophrenia and autism. This project aimed to find novel allosteric modulators binding in the ligand-binding domain (LBD) of the GluA2 and GluK1 and GluK2 subtypes of AMPA and kainate receptors, respectively, using protein purification and X-ray crystallography methodologies. Fragment screening for GluA2 identified eight novel fragments, five of which were located at the dimer interface and three located in a novel site near the glycine-threonine dipeptide linker. As regards kainate receptors, structural information on the Gluk1 and GluK2 LBD was obtained, both proteins were soaked with in-house fragments with one compound displaying 20% occupancy in the GluK2 dimer interface. These data form the basis of future studies in the search for novel drugs for the treatment of epilepsy and schizophrenia.