Nicotinic receptors have been implicated in a broad range of neurological disorders including Alzheimer's disease (AD), Schizophrenia, Autism, Frontal Lobe Epilepsy, Parkinson's disease, Tourette Syndrome and Attention Deficit Disorder. Given the increasing awareness of the role of nicotinic receptors in neurological disorders, it is not surprising that there is intense interest in developing therapeutics aimed at altering the expression or function of this important receptor family. A novel strategy for targeting nAChR subtypes is the identification of """"""""unconventional"""""""" or allosteric modulators. Highly selective modulators would be extremely valuable in investigating disease processes and as potential therapeutic drugs. Unfortunately, currently available potentiating agents typically display broad selectivity (although there have been some recent advances in 7 selective potentiators). The recent discovery of a natural product obtained from the Bryozoan, Flustra foliacea provides an exciting opportunity to develop a new class of selective modulatory agents. This compound (d-formylflustrabromide - dFBr) is a highly selective positive allosteric modulator of a4b2 nAChRs. Along with our collaborators, we have synthesized dFBr and evaluated its action on a4b2 receptors. This compound displays a number of properties that make it an ideal lead molecule. Our data suggest that dFBr would provide selective amplification of ACh responses with little change in response kinetics. The primary aims of this proposal are to: 1) Characterize the interaction of the dFBr class of compounds with the a4b2 receptor and 2) Synthesize and characterize new, optimized dFBr type ligands. These independent but mutually synergistic aims are focused on developing a fundamental understanding of dFBr action and interaction with this important receptor. We have already made significant progress in both aims. Preliminary mutagenesis data indicates a putative binding site at a subunit interface equivalent to the benzodiazepine binding site of GABA receptors and we have identified an improved dFBr analog in our preliminary synthetic studies that retains the ability to potentiate a4b2 receptors but without the inhibitory component at high concentrations that is a problem with dFBr itself. The current proposal expands our studies to characterization of dFBr's actions on the a4b2 receptor, mapping the binding domain and developing a refined dFBr pharmacophore.
This project explores the potential of a recently discovered natural product """"""""d- formylflustrabomide"""""""" (obtained originally from a species of Bryozoan or """"""""Sea Mat"""""""" found in the North Sea) as a lead molecule for a new class of drugs aimed at the treatment of CNS disorders such as Alzheimer's disease, Autism and Schizophrenia. The goal of this study is to develop the natural product into a more usable form with increased potency and less potential side effects. Since this is a new type of drug, it may open up new avenues for understanding and treating these diseases.
