Spadin Selectively Antagonizes Arachidonic Acid Activation of TREK-1 Channels

TREK-1 channel activity is a critical regulator of neuronal, cardiac, and smooth muscle physiology and pathology. The antidepressant peptide, spadin, has been proposed to be a TREK-1-specific blocker. Here we sought to examine the mechanism of action underlying spadin inhibition of TREK-1 channels....

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Main Authors: Ruolin Ma, Anthony Lewis
Format: Article
Language:English
Published: Frontiers Media S.A. 2020-04-01
Series:Frontiers in Pharmacology
Subjects:
Online Access:https://www.frontiersin.org/article/10.3389/fphar.2020.00434/full
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author Ruolin Ma
Anthony Lewis
author_facet Ruolin Ma
Anthony Lewis
author_sort Ruolin Ma
collection DOAJ
description TREK-1 channel activity is a critical regulator of neuronal, cardiac, and smooth muscle physiology and pathology. The antidepressant peptide, spadin, has been proposed to be a TREK-1-specific blocker. Here we sought to examine the mechanism of action underlying spadin inhibition of TREK-1 channels. Heterologous expression in Xenopus laevis oocytes and electrophysiological analysis using two-electrode voltage clamp in standard bath solutions was used to characterize the pharmacological profile of wild-type and mutant murine TREK-1 and TREK-2 channels using previously established human K2P activators; arachidonic acid (AA), cis-4,7,10,13,16,19-docosahexaenoic acid (DHA), BL-1249, and cinnamyl-3,4-dihydroxy-α-cyanocinnamate (CDC) and inhibitors; spadin and barium (Ba2+). Mouse TREK-1 and TREK-2 channel currents were both significantly increased by AA, BL-1249, and CDC, similar to their human homologs. Under basal conditions, both TREK-1 and TREK-2 currents were insensitive to application of spadin, but could be blocked by Ba2+. Spadin did not significantly inhibit either TREK-1 or TREK-2 currents either chemically activated by AA, BL-1249, or CDC, or structurally activated via a gating mutation. However, pre-exposure to spadin significantly perturbed the subsequent activation of TREK-1 currents by AA, but not TREK-2. Furthermore, spadin was unable to prevent activation of TREK-1 by BL-1249, CDC, or the related bioactive lipid, DHA. Spadin specifically antagonizes the activation of TREK-1 channels by AA, likely via an allosteric mechanism. Lack of intrinsic activity may explain the absence of clinical side effects during antidepressant therapy.
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spelling doaj.art-06c1bc6beb7c418cb5754e5e62dfcff92022-12-21T19:55:16ZengFrontiers Media S.A.Frontiers in Pharmacology1663-98122020-04-011110.3389/fphar.2020.00434519659Spadin Selectively Antagonizes Arachidonic Acid Activation of TREK-1 ChannelsRuolin MaAnthony LewisTREK-1 channel activity is a critical regulator of neuronal, cardiac, and smooth muscle physiology and pathology. The antidepressant peptide, spadin, has been proposed to be a TREK-1-specific blocker. Here we sought to examine the mechanism of action underlying spadin inhibition of TREK-1 channels. Heterologous expression in Xenopus laevis oocytes and electrophysiological analysis using two-electrode voltage clamp in standard bath solutions was used to characterize the pharmacological profile of wild-type and mutant murine TREK-1 and TREK-2 channels using previously established human K2P activators; arachidonic acid (AA), cis-4,7,10,13,16,19-docosahexaenoic acid (DHA), BL-1249, and cinnamyl-3,4-dihydroxy-α-cyanocinnamate (CDC) and inhibitors; spadin and barium (Ba2+). Mouse TREK-1 and TREK-2 channel currents were both significantly increased by AA, BL-1249, and CDC, similar to their human homologs. Under basal conditions, both TREK-1 and TREK-2 currents were insensitive to application of spadin, but could be blocked by Ba2+. Spadin did not significantly inhibit either TREK-1 or TREK-2 currents either chemically activated by AA, BL-1249, or CDC, or structurally activated via a gating mutation. However, pre-exposure to spadin significantly perturbed the subsequent activation of TREK-1 currents by AA, but not TREK-2. Furthermore, spadin was unable to prevent activation of TREK-1 by BL-1249, CDC, or the related bioactive lipid, DHA. Spadin specifically antagonizes the activation of TREK-1 channels by AA, likely via an allosteric mechanism. Lack of intrinsic activity may explain the absence of clinical side effects during antidepressant therapy.https://www.frontiersin.org/article/10.3389/fphar.2020.00434/fullspadinTREK-1TREK-2antagonismarachidonic acid
spellingShingle Ruolin Ma
Anthony Lewis
Spadin Selectively Antagonizes Arachidonic Acid Activation of TREK-1 Channels
Frontiers in Pharmacology
spadin
TREK-1
TREK-2
antagonism
arachidonic acid
title Spadin Selectively Antagonizes Arachidonic Acid Activation of TREK-1 Channels
title_full Spadin Selectively Antagonizes Arachidonic Acid Activation of TREK-1 Channels
title_fullStr Spadin Selectively Antagonizes Arachidonic Acid Activation of TREK-1 Channels
title_full_unstemmed Spadin Selectively Antagonizes Arachidonic Acid Activation of TREK-1 Channels
title_short Spadin Selectively Antagonizes Arachidonic Acid Activation of TREK-1 Channels
title_sort spadin selectively antagonizes arachidonic acid activation of trek 1 channels
topic spadin
TREK-1
TREK-2
antagonism
arachidonic acid
url https://www.frontiersin.org/article/10.3389/fphar.2020.00434/full
work_keys_str_mv AT ruolinma spadinselectivelyantagonizesarachidonicacidactivationoftrek1channels
AT anthonylewis spadinselectivelyantagonizesarachidonicacidactivationoftrek1channels