Novel light-responsive modulators/labels of TRPC3/6-channels

Mammalian Transient Receptor Potential (TRP) channels include six related protein families. Members of the human TRP Canonical (TRPC) subfamily (TRPC1/3/4/5/6/7), form channels that mediate Ca2+- and Na+-ion entry and are expressed in many mammalian cell types to serve a broad-range of important physiological processes. Recently, TRPC3/6 channels have been implicated in the pathogenesis of cardiovascular disorders including heart failure, arrhythmias, and sudden death. Consequently, TRPC channels have emerged as highly promising targets for drug development, while, at the same time, their exact cellular function and principles of pharmacologic modulation are still incompletely understood and require better understanding. For this, novel strategies to experimentally control channel function are urgently needed. These channels are endogenously controlled by plasma membrane lipid metabolites, which are difficult to administer in most experimental settings. Novel modulating or blocking ligands with potentially suitable selectivity for exact experimental control of TRPC3/6 channel have just recently been reported. One objective of this proposal is therefore the synthesis of small modulators (inhibitors/activators) of TRPC3/6-channels that response to light, allowing the control of biological events with unparalleled spatial and temporal precision so called photoswitches (e.g. azobenzens). Taking advantage of our experience in the synthesis of pyrazole-based inhibitors of TRPC3/6-channels and benzimidazolone- based activators as well as our expertise in microwave and continuous-flow chemistry, we aim to generate and explore various photoswitchable ligands in connection to the emerging pharmacology of TRPC3/6-channels. Another objective of ours, involving small photoresponsive molecules, is the synthesis of photoaffinity labels to help in the elucidation of potential ligand-binding sites in the TRPC3/6- channels as well as on the structure elucidation of TRPC3/6-channels. The research proposed herein is meant to become a significant contribution to a thrilling and rapidly growing field for optoregulation of biological functions in mammalian cells and for better understanding on the TRPC3/6-channel machinery. If positive results are obtained, the arising pharmacology will importantly aid investigations of the physiological and pathophysiological roles of TRPC channels, facilitate the validation of TRPCs as potential therapeutic targets in different channelopathies, and possibly provide foundations for drug discovery and development.

Mammalian Transient Receptor Potential (TRP) channels include six related protein families. Members of the human TRP Canonical (TRPC) subfamily (TRPC1/3/4/5/6/7), form channels that mediate Ca2+- and Na+-ion entry and are expressed in many mammalian cell types to serve a broad-range of important physiological processes. Recently, TRPC3/6 channels have been implicated in the pathogenesis of cardiovascular disorders including heart failure, arrhythmias, and sudden death but also in neurological disorders and cancer. Consequently, TRPC channels have emerged as highly promising targets for drug development, while, at the same time, their exact cellular function and principles of pharmacologic modulation are still incompletely understood and require better understanding. For this, novel strategies to experimentally control channel function are urgently needed. These channels are endogenously controlled by plasma membrane lipid metabolites, which are difficult to administer in most experimental settings. Novel modulating or blocking ligands with suitable selectivity for exact experimental control of TRPC3/6 activity have just recently been reported. One objective of this proposal was therefore the synthesis of small modulators (inhibitors/activators) of TRPC3/6-channels that response to light, allowing the control of biological events with unparalleled spatial and temporal precision so called photoswitches (e.g. azobenzenes). Taking advantage of our experience in the synthesis of pyrazole-based inhibitors of TRPC3/6-channels and benzimidazolone-based activators as well as our expertise in microwave and continuous-flow chemistry, we were able to generate and characterize various photoswitchable ligands to advance molecular pharmacology of TRPC3/6-channels. A specific focus of this project was the utilization of small photochromic ligands to explore ligand-binding sites in TRPC3/6-channel complexes and to aid elucidation of TRPC3/6-channels structure-function relations with the help of these (light-activated) molecules. Using our new synthetic activators, we were successful in identifying important elements in the protein structure of the TRPC3 channels. The achieved results present a significant contribution to the thrilling and rapidly growing field for optoregulation of biological functions in mammalian cells and for better understanding on the TRPC3/6-channel machinery. The obtained positive results, will importantly aid investigations of the physiological and pathophysiological roles of TRPC channels, facilitate the validation of TRPCs as potential therapeutic targets in different channelopathies, and possibly provide foundations for drug discovery and development. The obtained results were published in high-value scientific journals.