Regulation of glucocorticoid responsiveness in glaucomatous trabecular meshwork cells by glucocorticoid receptor-β

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Abstract

PURPOSE. Glucocorticoid administration can lead to increased intraocular pressure in greater than 90% of patients with primary open-angle glaucoma (POAG), compared with 30% to 40% of the general population. The molecular mechanisms for increased steroid responsiveness among patients with glaucoma are unknown. An alternative splicing variant of the human glucocorticoid receptor GRβ has dominant negative activity and has been implicated in a variety of steroid-resistant diseases. GRβ also may play a role in glucocorticoid hyperresponsiveness in glaucoma. METHODS. Western blot analysis was performed to detect the expression of GRα and GRβ in TM cells and its regulation by dexamethasone (DEX). Immunocytochemistry was used to compare the subcellular expression of GRβ between normal and glaucomatous TM cell lines. DEX transgene induction in a luciferase reporter was performed to investigate the differential glucocorticoid responsiveness between multiple normal and glaucomatous TM cell lines. Overexpression of GRβ was conducted in glaucomatous TM cell lines, and the regulation of GRβ in the Dex-induced reporter gene luciferase or endogenous myocilin and fibronectin expression were determined. RESULTS. Trabecular meshwork (TM) cell lines derived from normal individuals expressed higher levels of GRβ than did glaucomatous TM cells. Glaucomatous TM cells were more susceptible to DEX induction of a luciferase reporter gene than were TM cells derived from normal donors. Overexpression of GRβ in glaucomatous TM cells inhibited DEX induction of a luciferase reporter gene as well as the endogenous genes MYOC and fibronectin. CONCLUSIONS. The decreased amount of GRβ in glaucomatous TM cells could result in enhanced glucocorticoid responsiveness and ocular hypertension.

Original languageEnglish
Pages (from-to)4607-4616
Number of pages10
JournalInvestigative Ophthalmology and Visual Science
Volume46
Issue number12
DOIs
StatePublished - 1 Dec 2005

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Trabecular Meshwork
Glucocorticoid Receptors
Glucocorticoids
Luciferases
Dexamethasone
Reporter Genes
Cell Line
Fibronectins
Glaucoma
Steroids
Ocular Hypertension
Alternative Splicing
Intraocular Pressure
Transgenes
Western Blotting
Immunohistochemistry
Tissue Donors

Cite this

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title = "Regulation of glucocorticoid responsiveness in glaucomatous trabecular meshwork cells by glucocorticoid receptor-β",
abstract = "PURPOSE. Glucocorticoid administration can lead to increased intraocular pressure in greater than 90{\%} of patients with primary open-angle glaucoma (POAG), compared with 30{\%} to 40{\%} of the general population. The molecular mechanisms for increased steroid responsiveness among patients with glaucoma are unknown. An alternative splicing variant of the human glucocorticoid receptor GRβ has dominant negative activity and has been implicated in a variety of steroid-resistant diseases. GRβ also may play a role in glucocorticoid hyperresponsiveness in glaucoma. METHODS. Western blot analysis was performed to detect the expression of GRα and GRβ in TM cells and its regulation by dexamethasone (DEX). Immunocytochemistry was used to compare the subcellular expression of GRβ between normal and glaucomatous TM cell lines. DEX transgene induction in a luciferase reporter was performed to investigate the differential glucocorticoid responsiveness between multiple normal and glaucomatous TM cell lines. Overexpression of GRβ was conducted in glaucomatous TM cell lines, and the regulation of GRβ in the Dex-induced reporter gene luciferase or endogenous myocilin and fibronectin expression were determined. RESULTS. Trabecular meshwork (TM) cell lines derived from normal individuals expressed higher levels of GRβ than did glaucomatous TM cells. Glaucomatous TM cells were more susceptible to DEX induction of a luciferase reporter gene than were TM cells derived from normal donors. Overexpression of GRβ in glaucomatous TM cells inhibited DEX induction of a luciferase reporter gene as well as the endogenous genes MYOC and fibronectin. CONCLUSIONS. The decreased amount of GRβ in glaucomatous TM cells could result in enhanced glucocorticoid responsiveness and ocular hypertension.",
author = "Xinyu Zhang and Abbot Clark and Thomas Yorio",
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Regulation of glucocorticoid responsiveness in glaucomatous trabecular meshwork cells by glucocorticoid receptor-β. / Zhang, Xinyu; Clark, Abbot; Yorio, Thomas.

In: Investigative Ophthalmology and Visual Science, Vol. 46, No. 12, 01.12.2005, p. 4607-4616.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Regulation of glucocorticoid responsiveness in glaucomatous trabecular meshwork cells by glucocorticoid receptor-β

AU - Zhang, Xinyu

AU - Clark, Abbot

AU - Yorio, Thomas

PY - 2005/12/1

Y1 - 2005/12/1

N2 - PURPOSE. Glucocorticoid administration can lead to increased intraocular pressure in greater than 90% of patients with primary open-angle glaucoma (POAG), compared with 30% to 40% of the general population. The molecular mechanisms for increased steroid responsiveness among patients with glaucoma are unknown. An alternative splicing variant of the human glucocorticoid receptor GRβ has dominant negative activity and has been implicated in a variety of steroid-resistant diseases. GRβ also may play a role in glucocorticoid hyperresponsiveness in glaucoma. METHODS. Western blot analysis was performed to detect the expression of GRα and GRβ in TM cells and its regulation by dexamethasone (DEX). Immunocytochemistry was used to compare the subcellular expression of GRβ between normal and glaucomatous TM cell lines. DEX transgene induction in a luciferase reporter was performed to investigate the differential glucocorticoid responsiveness between multiple normal and glaucomatous TM cell lines. Overexpression of GRβ was conducted in glaucomatous TM cell lines, and the regulation of GRβ in the Dex-induced reporter gene luciferase or endogenous myocilin and fibronectin expression were determined. RESULTS. Trabecular meshwork (TM) cell lines derived from normal individuals expressed higher levels of GRβ than did glaucomatous TM cells. Glaucomatous TM cells were more susceptible to DEX induction of a luciferase reporter gene than were TM cells derived from normal donors. Overexpression of GRβ in glaucomatous TM cells inhibited DEX induction of a luciferase reporter gene as well as the endogenous genes MYOC and fibronectin. CONCLUSIONS. The decreased amount of GRβ in glaucomatous TM cells could result in enhanced glucocorticoid responsiveness and ocular hypertension.

AB - PURPOSE. Glucocorticoid administration can lead to increased intraocular pressure in greater than 90% of patients with primary open-angle glaucoma (POAG), compared with 30% to 40% of the general population. The molecular mechanisms for increased steroid responsiveness among patients with glaucoma are unknown. An alternative splicing variant of the human glucocorticoid receptor GRβ has dominant negative activity and has been implicated in a variety of steroid-resistant diseases. GRβ also may play a role in glucocorticoid hyperresponsiveness in glaucoma. METHODS. Western blot analysis was performed to detect the expression of GRα and GRβ in TM cells and its regulation by dexamethasone (DEX). Immunocytochemistry was used to compare the subcellular expression of GRβ between normal and glaucomatous TM cell lines. DEX transgene induction in a luciferase reporter was performed to investigate the differential glucocorticoid responsiveness between multiple normal and glaucomatous TM cell lines. Overexpression of GRβ was conducted in glaucomatous TM cell lines, and the regulation of GRβ in the Dex-induced reporter gene luciferase or endogenous myocilin and fibronectin expression were determined. RESULTS. Trabecular meshwork (TM) cell lines derived from normal individuals expressed higher levels of GRβ than did glaucomatous TM cells. Glaucomatous TM cells were more susceptible to DEX induction of a luciferase reporter gene than were TM cells derived from normal donors. Overexpression of GRβ in glaucomatous TM cells inhibited DEX induction of a luciferase reporter gene as well as the endogenous genes MYOC and fibronectin. CONCLUSIONS. The decreased amount of GRβ in glaucomatous TM cells could result in enhanced glucocorticoid responsiveness and ocular hypertension.

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U2 - 10.1167/iovs.05-0571

DO - 10.1167/iovs.05-0571

M3 - Article

VL - 46

SP - 4607

EP - 4616

JO - Investigative Ophthalmology and Visual Science

JF - Investigative Ophthalmology and Visual Science

SN - 0146-0404

IS - 12

ER -