Novel potent blockers for TWIK-1/TREK-1 heterodimers as potential
antidepressants
Abstract
Background and Purpose: TREK-1 (TWIK-related potassium channel-1) is a
subunit of the two-pore domain potassium (K2p) channel and is widely
expressed in the brain. TREK-1 knockout mice were shown to have
antidepressant-like effects, providing evidence for the channel’s
potential as a therapeutic target. However, currently there is no good
pharmacological inhibitor specifically targeting TREK-1 containing K2p
channels that also displays similar antidepressant-like effects.
Experimental Approach: We sought to find selective and potent inhibitors
for TREK-1 related dimers both in vitro and in vivo. We synthesized and
evaluated 2-hydroxy-3-phenoxypropyl piperidine derivatives yielding a
library from which many TREK-1 targeting candidates emerged. Key
Results: Hydroxyl-phenyl- (2a), piperidino- (2g), and pyrrolidino- (2h)
piperidinyl substituted compounds showed high potencies to TREK-1
homodimers with significant antidepressant-like effects in forced swim
test and tail suspension test. Interestingly, these compounds were found
to have high potencies to TWIK-1/TREK-1 heterodimers, contrastingly,
difluoropiperidinyl-4-fluorophenoxy (3e) and
4-hydroxyphenyl-piperidinyl-4-fluorophenoxy (3j) compounds had high
potencies to TREK-1 homodimer but lower potency to TWIK-1/TREK-1
heterodimers without significant antidepressant-like effects. We
observed positive correlation between inhibition potency to
TWIK-1/TREK-1 and immobility time, and no correlation between inhibition
potency to TREK-1 homodimer and immobility time. This was consistent
with molecular docking simulations of selected compounds to TREK-1
homodimeric and TWIK-1/TREK-1 heterodimeric models. Existing
antidepressant fluoxetine was also found to potently inhibit
TWIK-1/TREK-1 heterodimers. Conclusion and Implications: Our study
reveals novel potent TWIK-1/TREK-1 inhibitors 2a, 2g, and 2h as
potential antidepressants and suggest that the TWIK-1/TREK-1 heterodimer
could be a potential novel molecular therapeutic target for
antidepressants.