Mechano- and glucocorticoid-sensitive TREK-1 channels regulate conventional outflow and intraocular pressure
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Purpose: The purpose of this study was twofold: to determine the molecular link between corticosteroid exposure and mechanosensation and to establish the role of mechanosensitive TWIK-related potassium channel-1 (TREK-1) in the regulation of aqueous humor outflow and corticosteroid-induced ocular hypertension (OHT).
Methods: Real-time PCR was used to determine the corticosteroid dexamethasone (DEX) dependence of expression of tandem-pore potassium (K2P), transient receptor potential vanilloid (TRPV), Piezo channel, extracellular matrix (ECM), and fibrotic marker genes in mouse trabecular meshwork (mTM) cells. Immunohistochemistry was employed to assess TREK-1 localization, iPerfusion to determine the TREK-1 dependence of conventional outflow, and tonometry to track intraocular pressure (IOP) in mouse eyes. Telemetry additionally tested TREK-1 dependence of OHT in rat. Steroid-induced transcriptional suppression of mTM Kcnk2 was validated by whole-cell recording in primary human trabecular meshwork (TM) cells.
Results: The tandem pore K+ channel transcriptome in mTM cells was dominated by Trek-1 (Kcnk2) mRNA; with residual levels of Traak and Thik-2 transcripts; and low levels of Trek-2, Twik3, and Task1 expression. DEX upregulated Fsp1 and suppressed Kcnk2 expression without affecting Trpv4, Piezo1, or Trpc1 mRNA content. The TREK-1 agonist ML-402 doubled outflow facility in mouse eyes and reduced IOP in the mouse model of DEX-induced OHT and in rat eyes with spontaneously elevated IOP. Chronic DEX exposure depolarized human primary TM (pTM) cells and reduced the amplitude of the ML-402-evoked current.
Conclusions: Ocular overexposure to corticosteroids may compromise IOP homeostasis by impairing TM expression and function of TREK-1. Pharmacological activation of TREK-1 facilitates conventional outflow and could help lower IOP in eyes with steroid-induced ocular hypertension.
Methods: Real-time PCR was used to determine the corticosteroid dexamethasone (DEX) dependence of expression of tandem-pore potassium (K2P), transient receptor potential vanilloid (TRPV), Piezo channel, extracellular matrix (ECM), and fibrotic marker genes in mouse trabecular meshwork (mTM) cells. Immunohistochemistry was employed to assess TREK-1 localization, iPerfusion to determine the TREK-1 dependence of conventional outflow, and tonometry to track intraocular pressure (IOP) in mouse eyes. Telemetry additionally tested TREK-1 dependence of OHT in rat. Steroid-induced transcriptional suppression of mTM Kcnk2 was validated by whole-cell recording in primary human trabecular meshwork (TM) cells.
Results: The tandem pore K+ channel transcriptome in mTM cells was dominated by Trek-1 (Kcnk2) mRNA; with residual levels of Traak and Thik-2 transcripts; and low levels of Trek-2, Twik3, and Task1 expression. DEX upregulated Fsp1 and suppressed Kcnk2 expression without affecting Trpv4, Piezo1, or Trpc1 mRNA content. The TREK-1 agonist ML-402 doubled outflow facility in mouse eyes and reduced IOP in the mouse model of DEX-induced OHT and in rat eyes with spontaneously elevated IOP. Chronic DEX exposure depolarized human primary TM (pTM) cells and reduced the amplitude of the ML-402-evoked current.
Conclusions: Ocular overexposure to corticosteroids may compromise IOP homeostasis by impairing TM expression and function of TREK-1. Pharmacological activation of TREK-1 facilitates conventional outflow and could help lower IOP in eyes with steroid-induced ocular hypertension.
Date Issued
2025-11-01
Date Acceptance
2025-10-27
Citation
Investigative Ophthalmology and Visual Science, 2025, 66 (14)
URL
purpose:%20The%20purpose%20of%20this%20study%20was%20twofold:%20to%20determine%20the%20molecular%20link%20between%20corticosteroid%20exposure%20and%20mechanosensation%20and%20to%20establish%20the%20role%20of%20mechanosensitive%20TWIK-related%20potassium%20channel-1%20(TREK-1)%20in%20the%20regulation%20of%20aqueous%20humor%20outflow%20and%20corticosteroid-induced%20ocular%20hypertension%20(OHT).%20%20Methods:%20Real-time%20PCR%20was%20used%20to%20determine%20the%20corticosteroid%20dexamethasone%20(DEX)%20dependence%20of%20expression%20of%20tandem-pore%20potassium%20(K2P),%20transient%20receptor%20potential%20vanilloid%20(TRPV),%20Piezo%20channel,%20extracellular%20matrix%20(ECM),%20and%20fibrotic%20marker%20genes%20in%20mouse%20trabecular%20meshwork%20(mTM)%20cells.%20Immunohistochemistry%20was%20employed%20to%20assess%20TREK-1%20localization,%20iPerfusion%20to%20determine%20the%20TREK-1%20dependence%20of%20conventional%20outflow,%20and%20tonometry%20to%20track%20intraocular%20pressure%20(IOP)%20in%20mouse%20eyes.%20Telemetry%20additionally%20tested%20TREK-1%20dependence%20of%20OHT%20in%20rat.%20Steroid-induced%20transcriptional%20suppression%20of%20mTM%20Kcnk2%20was%20validated%20by%20whole-cell%20recording%20in%20primary%20human%20trabecular%20meshwork%20(TM)%20cells.%20%20Results:%20The%20tandem%20pore%20K+%20channel%20transcriptome%20in%20mTM%20cells%20was%20dominated%20by%20Trek-1%20(Kcnk2)%20mRNA;%20with%20residual%20levels%20of%20Traak%20and%20Thik-2%20transcripts;%20and%20low%20levels%20of%20Trek-2,%20Twik3,%20and%20Task1%20expression.%20DEX%20upregulated%20Fsp1%20and%20suppressed%20Kcnk2%20expression%20without%20affecting%20Trpv4,%20Piezo1,%20or%20Trpc1%20mRNA%20content.%20The%20TREK-1%20agonist%20ML-402%20doubled%20outflow%20facility%20in%20mouse%20eyes%20and%20reduced%20IOP%20in%20the%20mouse%20model%20of%20DEX-induced%20OHT%20and%20in%20rat%20eyes%20with%20spontaneously%20elevated%20IOP.%20Chronic%20DEX%20exposure%20depolarized%20human%20primary%20TM%20(pTM)%20cells%20and%20reduced%20the%20amplitude%20of%20the%20ML-402-evoked%20current.%20%20Conclusions:%20Ocular%20overexposure%20to%20corticosteroids%20may%20compromise%20IOP%20homeostasis%20by%20impairing%20TM%20expression%20and%20function%20of%20TREK-1.%20Pharmacological%20activation%20of%20TREK-1%20facilitates%20conventional%20outflow%20and%20could%20help%20lower%20IOP%20in%20eyes%20with%20steroid-induced%20ocular%20hypertension.
ISSN
0146-0404
Publisher
The Association for Research in Vision and Ophthalmology
Journal / Book Title
Investigative Ophthalmology and Visual Science
Volume
66
Issue
14
Copyright Statement
Copyright 2025 The Authors This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/41268978
PII: 2811136
Subjects
CELLS
DEXAMETHASONE
electrophysiology
EXPRESSION
EYES
HUMAN TRABECULAR MESHWORK
INDUCED OCULAR HYPERTENSION
intraocular pressure
Life Sciences & Biomedicine
mechanosensation
Ophthalmology
outflow facility
Science & Technology
steroid glaucoma
TRAAK
TRANSDUCTION
TREK-1
TRPV4
ULTRASTRUCTURAL-CHANGES
Publication Status
Published
Coverage Spatial
United States
Article Number
57
Date Publish Online
2025-11-21