Fragment-based drug discovery using stabilized α1-adrenoceptors
- Department / Centre
- Biochemistry and Pharmacology
|Dr Daniel Scottemail@example.com|
Summary The Scott group interrogates the molecular mechanisms underlying cellular signalling and exploits these details to develop new tools for drug discovery. A key focus is on G protein-coupled receptors (GPCRs), the largest, yet potentially most underexploited class of drug targets. Our projects combine a wide range of methods such as: protein engineering, directed evolution, cell-based binding and signalling assays, lentivirus, X-ray crystallography, NMR, fluorescence microscopy, electron microscopy, computational modelling, and rational drug design.
α1A- and α1B-adrenoceptors (α1A-AR and α1B-AR) are closely related GPCRs that modulate the peripheral and central nervous systems in response to binding epinephrine and norepinephrine. α1A-AR and α1B-AR are putative drug targets for treating heart failure, epilepsy and Alzheimer's disease. However, these receptors represent prototypical GPCR subtypes, where determining the physiological roles and clinical targeting of α1A-AR and α1B-AR individually has been hindered due to their highly similar agonist binding sites and a subsequent lack of subtype selective tool ligands. Thus there is a need to identify novel, sub-type selective tool ligands to probe the validity of targeting α1A-AR or α1B-AR for these diseases. Fragment screening is a validated approach for identifying and optimizing compounds that are selective for certain protein family members over others, but has not been directly applied to closely related GPCR subtypes. The primary reason for this is that the instability of purified GPCR preparations makes screening with the biophysical methods required for fragment screening challenging. We generated thermostabilized α1A-AR and α1B-AR variants suitable for biophysical studies, allowing the screening of a small, yet diverse fragment library with NMR spectroscopy and surface plasmon resonance. This screen identified two structurally related hits that preferentially bound α1B-AR over α1A-AR, one of which was subsequently shown to exhibit 10-fold selectivity for inhibiting α1B-AR signalling. Another hit was a selective α1A-AR agonist. To develop these hits into tool compounds and potentially drug leads, this project will focus on understanding their structure-activity relationships of the hit molecules at each receptor. This will be probed using traditional molecular pharmacology and using biophysical approaches such as NMR. The resultant information will be used to develop novel compounds to elucidate the individual physiological roles of α1A-AR and α1B-AR and their potential as targets for disease treatments. Students will be trained in: protein expression and purification, GPCR pharmacological assays, ligand binding assays, computational ligand docking and ligand design.