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J Gen Physiol. 2018 Dec 3;150(12):1660-1675. doi: 10.1085/jgp.201812179. Epub 2018 Nov 16.

TREK-1 channels regulate pressure sensitivity and calcium signaling in trabecular meshwork cells.

Author information

1
Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT yarishkin@gmail.com.
2
Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT.
3
Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, UT.
4
Bioengineering Graduate Program, University of Utah School of Medicine, Salt Lake City, UT.
5
Institute de Pharmacologie Moléculaire et Cellulaire, CNRS, Valbonne, France.
6
Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT david.krizaj@hsc.utah.edu.
7
Department of Neurobiology & Anatomy, University of Utah School of Medicine, Salt Lake City, UT.

Abstract

Mechanotransduction by the trabecular meshwork (TM) is an essential component of intraocular pressure regulation in the vertebrate eye. This process is compromised in glaucoma but is poorly understood. In this study, we identify transient receptor potential vanilloid isoform 4 (TRPV4) and TWIK-related potassium channel-1 (TREK-1) as key molecular determinants of TM membrane potential, pressure sensitivity, calcium homeostasis, and transcellular permeability. We show that resting membrane potential in human TM cells is unaffected by "classical" inhibitors of voltage-activated, calcium-activated, and inwardly rectifying potassium channels but is depolarized by blockers of tandem-pore K+ channels. Using gene profiling, we reveal the presence of TREK-1, TASK-1, TWIK-2, and THIK transcripts in TM cells. Pressure stimuli, arachidonic acid, and TREK-1 activators hyperpolarize these cells, effects that are antagonized by quinine, amlodipine, spadin, and short-hairpin RNA-mediated knockdown of TREK-1 but not TASK-1. Activation and inhibition of TREK-1 modulates [Ca2+]TM and lowers the impedance of cell monolayers. Together, these results suggest that tensile homeostasis in the TM may be regulated by balanced, pressure-dependent activation of TRPV4 and TREK-1 mechanotransducers.

PMID:
30446509
PMCID:
PMC6279358
[Available on 2019-06-03]
DOI:
10.1085/jgp.201812179

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