A Direct Interaction between Cyclodextrins and TASK Channels Decreases the Leak Current in Cerebellar Granule Neurons

Rafael Zúñiga; Daniel Mancilla; Tamara Rojas; Fernando Vergara; Wendy González; Marcelo A Catalán; Leandro Zúñiga

doi:10.3390/biology11081097

A Direct Interaction between Cyclodextrins and TASK Channels Decreases the Leak Current in Cerebellar Granule Neurons

Biology (Basel). 2022 Jul 23;11(8):1097. doi: 10.3390/biology11081097.

Authors

Rafael Zúñiga^{1

2

3}, Daniel Mancilla^{1

2}, Tamara Rojas^{1

2}, Fernando Vergara^{1

4}, Wendy González⁴, Marcelo A Catalán⁵, Leandro Zúñiga^{1

2}

Affiliations

¹ Laboratorio de Fisiología Molecular, Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
² Centro de Nanomedicina, Diagnóstico y Desarrollo de Fármacos (ND3), Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
³ Instituto de Investigación Interdisciplinaria, Vicerrectoría Académica, Universidad de Talca, Talca 3460000, Chile.
⁴ Center for Bioinformatics and Molecular Simulations (CBSM), Universidad de Talca, Talca 3460000, Chile.
⁵ Facultad de Medicina, Instituto de Fisiología, Universidad Austral de Chile, Valdivia 5090010, Chile.

Abstract

Two pore domain potassium channels (K2P) are strongly expressed in the nervous system (CNS), where they play a central role in excitability. These channels give rise to background K⁺ currents, also known as IK_SO (standing-outward potassium current). We detected the expression in primary cultured cerebellar granule neurons (CGNs) of TWIK-1 (K2P1), TASK-1 (K2P3), TASK-3 (K2P9), and TRESK (K2P18) channels by immunocytochemistry and their association with lipid rafts using the specific lipids raft markers flotillin-2 and caveolin-1. At the functional level, methyl-β-cyclodextrin (MβCD, 5 mM) reduced IK_SO currents by ~40% in CGN cells. To dissect out this effect, we heterologously expressed the human TWIK-1, TASK-1, TASK-3, and TRESK channels in HEK-293 cells. MβCD directly blocked TASK-1 and TASK-3 channels and the covalently concatenated heterodimer TASK-1/TASK-3 currents. Conversely, MβCD did not affect TWIK-1- and TRESK-mediated K+ currents. On the other hand, the cholesterol-depleting agent filipin III did not affect TASK-1/TASK-3 channels. Together, the results suggest that neuronal background K⁺ channels are associated to lipid raft environments whilst the functional activity is independent of the cholesterol membrane organization.

Keywords: K+ leak currents; K2P channels; cerebellar granule neurons; cyclodextrin.

Grants and funding

This work was supported by Fondecyt 1191133 (F.V., W.G. and L.Z.), Fondecyt 1211838 to M.A.C., and FIC-R “Portafolio de servicios para la caracterización de blancos terapéuticos para el tratamiento de cáncer y enfermedades crónicas no transmisibles” (W.G. and L.Z.).