Characterisation of C101248: A novel selective THIK-1 channel inhibitor for the modulation of microglial NLRP3-inflammasome

• DOI: 10.1016/j.neuropharm.2022.109330
• Publication Date: 2022-11-12T03:08:59Z
• Authors: Bernardino Ossola; Ali Rifat; Anna Rowland; Helen Hunter; Samuel Drinkall; Clare Bender; Mayida Hamlischer; Martin Teall; Russell Burley; Daneil F. Barker; David Cadwalladr; Louise Dickson; Jason M.K. Lawrence; Jenna R.M. Harvey; Marina Lizio; Xiao Xu; Edel Kavanagh; Toni Cheung; Steve Sheardown; Catherine B. Lawr...; Michael Harte; David Brough; Christian Madry; Kim Matthews; Kevin Doyle; Keith Page; Justin Powell; Nicola L. Brice; Roland W. Bürli; Mark B. Carlton; Lee A. Dawson
• Keywords: 0301 basic medicine; 0303 health sciences; Inflammasomes; Brain; Article; 3. Good health; Mice; 03 medical and health sciences; Potassium Channels, Tandem Pore Domain; Alzheimer Disease; Neuroinflammatory Diseases; NLR Family, Pyrin Domain-Containing 3 Protein; Animals; Humans; Microglia

Neuroinflammation, specifically the NLRP3 inflammasome cascade, is a common underlying pathological feature of many neurodegenerative diseases. Evidence suggests that NLRP3 activation involves changes in intracellular K+. Nuclear Enriched Transcript Sort Sequencing (NETSseq), which allows for deep sequencing of purified cell types from human post-mortem brain tissue, demonstrated a highly specific expression of the tandem pore domain halothane-inhibited K+ channel 1 (THIK-1) in microglia compared to other glial and neuronal cell types in the human brain. NETSseq also showed a significant increase of THIK-1 in microglia isolated from cortical regions of brains with Alzheimer's disease (AD) relative to control donors. Herein, we report the discovery and pharmacological characterisation of C101248, the first selective small-molecule inhibitor of THIK-1. C101248 showed a concentration-dependent inhibition of both mouse and human THIK-1 (IC50: ∼50 nM) and was inactive against K2P family members TREK-1 and TWIK-2, and Kv2.1. Whole-cell patch-clamp recordings of microglia from mouse hippocampal slices showed that C101248 potently blocked both tonic and ATP-evoked THIK-1 K+ currents. Notably, C101248 had no effect on other constitutively active resting conductance in slices from THIK-1-depleted mice. In isolated microglia, C101248 prevented NLRP3-dependent release of IL-1β, an effect not seen in THIK-1-depleted microglia. In conclusion, we demonstrated that inhibiting THIK-1 (a microglia specific gene that is upregulated in brains from donors with AD) using a novel selective modulator attenuates the NLRP3-dependent release of IL-1β from microglia, which suggests that this channel may be a potential therapeutic target for the modulation of neuroinflammation in AD.