1. Academic Validation
  2. Characterization and regulation of wild-type and mutant TASK-1 two pore domain potassium channels indicated in pulmonary arterial hypertension

Characterization and regulation of wild-type and mutant TASK-1 two pore domain potassium channels indicated in pulmonary arterial hypertension

  • J Physiol. 2019 Feb;597(4):1087-1101. doi: 10.1113/JP277275.
Kevin P Cunningham 1 Robyn G Holden 1 Pilar M Escribano-Subias 2 Angel Cogolludo 3 4 Emma L Veale 1 Alistair Mathie 1
Affiliations

Affiliations

  • 1 Medway School of Pharmacy, University of Kent and University of Greenwich, Chatham Maritime, Kent, UK.
  • 2 Red de Investigación Cardiovascular, Instituto de Salud Carlos III, Madrid, Spain.
  • 3 Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.
  • 4 Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain.
Abstract

Key points: The TASK-1 channel gene (KCNK3) has been identified as a possible disease-causing gene in heritable pulmonary arterial hypertension (PAH). In the present study, we show that novel mutated TASK-1 channels, seen in PAH patients, have a substantially reduced current compared to wild-type TASK-1 channels. These mutated TASK-1 channels are located at the plasma membrane to the same degree as wild-type TASK-1 channels. ONO-RS-082 and alkaline pH 8.4 both activate TASK-1 channels but do not recover current through mutant TASK-1 channels. We show that the Guanylate Cyclase Activator, riociguat, a novel treatment for PAH, enhances current through TASK-1 channels but does not recover current through mutant TASK-1 channels.

Abstract: Pulmonary arterial hypertension (PAH) affects ∼15-50 people per million. KCNK3, the gene that encodes the two pore domain Potassium Channel TASK-1 (K2P3.1), has been identified as a possible disease-causing gene in heritable PAH. Recently, two new mutations have been identified in KCNK3 in PAH patients: G106R and L214R. The present study aimed to characterize the functional properties and regulation of wild-type (WT) and mutated TASK-1 channels and determine how these might contribute to PAH and its treatment. Currents through WT and mutated human TASK-1 channels transiently expressed in tsA201 cells were measured using whole-cell patch clamp electrophysiology. Localization of fluorescence-tagged channels was visualized using confocal microscopy and quantified with in-cell and on-cell westerns. G106R or L214R mutated channels were located at the plasma membrane to the same degree as WT channels; however, their current was markedly reduced compared to WT TASK-1 channels. Functional current through these mutated channels could not be restored using activators of WT TASK-1 channels (pH 8.4, ONO-RS-082). The Guanylate Cyclase Activator, riociguat, enhanced current through WT TASK-1 channels; however, similar to the other activators investigated, riociguat did not have any effect on current through mutated TASK-1 channels. Thus, novel mutations in TASK-1 seen in PAH substantially alter the functional properties of these channels. Current through these channels could not be restored by activators of TASK-1 channels. Riociguat enhancement of current through TASK-1 channels could contribute to its therapeutic benefit in the treatment of PAH.

Keywords

KCNK3 (TASK-1) potassium channel; Pulmonary arterial hypertension; riociguat.

Figures
Products