Mechanisms of activation of lysosomal two-pore channel TPC2, a potential novel target for the treatment of lysosomal storage disorders and neurodegenerative diseases

• Applicant: Professor Dr. Christian Michael Grimm
• Subject Area: Pharmacology ; Biophysics
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 440563025

Endolysosomal ion channels, in particular the two-pore channels (TPCs) are currently garnering much interest due to its pathophysiological relevance (given links to several diseases) and from a structural standpoint (with emerging cryoEM structures). But uncertainty surrounding fundamental properties of TPCs including how they are activated and their ion permeability, coupled with a limited pharmacological tool set is slowing progress. This proposal will address these gaps in detail. We will 1) validate new chemical tools to study TPCs, in particular TPC2 in a physiological and pathophysiological context and we will 2) facilitate TPC2 drug discovery and design by laying the foundations for a clearer understanding of how TPC2 can conduct different ions in response to different activating cues with potentially differential physiological consequences. By using a combination of Ca2+ imaging, molecular biology and electrophysiology, we apply the first-in-kind lipophilic agonists of TPC2 that we have discovered to demonstrate that the ion selectivity of TPC2 is agonist-dependent and not fixed. This has very important implications for the physiological and pathophysiological roles and endogenous activation mechanisms of TPC2 and consequently for drug discovery and drug design. In order to establish TPC2 as a target to treat, e.g. LSDs or neurodegenerative diseases, insights into these different activation mechanisms and endogenous stimulation pathways are crucial and this work aims to deliver the missing knowledge gaps.

• DFG Programme: Research Grants