Author/Editor		Yarishkin, Oleg; Phuong, Tam T. T.; Bretz, Colin A.; Olsen, Kenneth W.; Baumann, Jackson M.; Lakk, Monika; Crandall, Alan; Heurteaux, Catherine; Hartnett, Mary E.; Križaj, David
Title		TREK-1 channels regulate pressure sensitivity and calcium signaling in trabecular meshwork cells
Type		članek
Vol. and No.		Letnik 150, št. 12
Publication year		2018
Volume		str. 1660-1675
ISSN		0022-1295 - The Journal of general physiology
Language		eng
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.
Keywords		trabecular meshwork potassium channel calcium signaling trabekularna mrežica kalijev kanal signalizacija kalcija