Neuroprotective effects of transcription factor brn3b in an ocular hypertension rat model of glaucoma

Dorota Luiza Stankowska, Alena Z. Minton, Margaret A. Rutledge, Brett H. Mueller, Nitasha R. Phatak, Shaoqing He, Hai Ying Ma, Michael J. Forster, Thomas Yorio, Raghu Krishnamoorthy

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Abstract

PURPOSE. Glaucoma is an optic neuropathy commonly associated with elevated intraocular pressure (IOP), leading to optic nerve head (ONH) cupping, axon loss, and apoptosis of retinal ganglion cells (RGCs), which could ultimately result in blindness. Brn3b is a class-4 POU domain transcription factor that plays a key role in RGC development, axon outgrowth, and pathfinding. Previous studies suggest that a decrease in Brn3b levels occurs in animal models of glaucoma. The goal of this study was to determine if adeno-associated virus (AAV)- directed overexpression of the Brn3b protein could have neuroprotective effects following elevated IOP-mediated neurodegeneration.

METHODS. Intraocular pressure was elevated in one eye of Brown Norway rats (Rattus norvegicus), following which the IOP-elevated eyes were intravitreally injected with AAV constructs encoding either the GFP (rAAV-CMV-GFP and rAAV-hsyn-GFP) or Brn3b (rAAVCMV- Brn3b and rAAV-hsyn-Brn3b). Retina sections through the ONH were stained for synaptic plasticity markers and neuroprotection was assessed by RGC counts and visual acuity tests.

RESULTS. Adeno-associated virus–mediated expression of the Brn3b protein in IOP-elevated rat eyes promoted an upregulation of growth associated protein-43 (GAP-43), actin binding LIM protein (abLIM) and acetylated a-tubulin (ac-Tuba) both posterior to the ONH and in RGCs. The RGC survival as well as axon integrity score were significantly improved in IOP-elevated rAAV-hsyn-Brn3b–injected rats compared with those of the IOP-elevated rAAV-hsyn-GFP-injected rats. Additionally, intravitreal rAAV-hsyn-Brn3b administration significantly restored the visual optomotor response in IOP-elevated rat eyes.

CONCLUSIONS. Adeno-associated virus–mediated Brn3b protein expression may be a suitable approach for promoting neuroprotection in animal models of glaucoma.

Original languageEnglish
Pages (from-to)893-907
Number of pages15
JournalInvestigative Ophthalmology and Visual Science
Volume56
Issue number2
DOIs
StatePublished - 1 Jan 2015

Fingerprint

Ocular Hypertension
Neuroprotective Agents
Intraocular Pressure
Glaucoma
Transcription Factors
Retinal Ganglion Cells
Optic Disk
Dependovirus
Axons
Animal Models
POU Domain Factors
GAP-43 Protein
Microfilament Proteins
Optic Nerve Diseases
Proteins
Neuronal Plasticity
Blindness
Tubulin
Visual Acuity
Retina

Keywords

  • Brn3b
  • Gene therapy
  • Glaucoma
  • Morrison’s model
  • Neuroprotection

Cite this

@article{ec842c59e19f43a69444b13a57640751,
title = "Neuroprotective effects of transcription factor brn3b in an ocular hypertension rat model of glaucoma",
abstract = "PURPOSE. Glaucoma is an optic neuropathy commonly associated with elevated intraocular pressure (IOP), leading to optic nerve head (ONH) cupping, axon loss, and apoptosis of retinal ganglion cells (RGCs), which could ultimately result in blindness. Brn3b is a class-4 POU domain transcription factor that plays a key role in RGC development, axon outgrowth, and pathfinding. Previous studies suggest that a decrease in Brn3b levels occurs in animal models of glaucoma. The goal of this study was to determine if adeno-associated virus (AAV)- directed overexpression of the Brn3b protein could have neuroprotective effects following elevated IOP-mediated neurodegeneration.METHODS. Intraocular pressure was elevated in one eye of Brown Norway rats (Rattus norvegicus), following which the IOP-elevated eyes were intravitreally injected with AAV constructs encoding either the GFP (rAAV-CMV-GFP and rAAV-hsyn-GFP) or Brn3b (rAAVCMV- Brn3b and rAAV-hsyn-Brn3b). Retina sections through the ONH were stained for synaptic plasticity markers and neuroprotection was assessed by RGC counts and visual acuity tests.RESULTS. Adeno-associated virus–mediated expression of the Brn3b protein in IOP-elevated rat eyes promoted an upregulation of growth associated protein-43 (GAP-43), actin binding LIM protein (abLIM) and acetylated a-tubulin (ac-Tuba) both posterior to the ONH and in RGCs. The RGC survival as well as axon integrity score were significantly improved in IOP-elevated rAAV-hsyn-Brn3b–injected rats compared with those of the IOP-elevated rAAV-hsyn-GFP-injected rats. Additionally, intravitreal rAAV-hsyn-Brn3b administration significantly restored the visual optomotor response in IOP-elevated rat eyes.CONCLUSIONS. Adeno-associated virus–mediated Brn3b protein expression may be a suitable approach for promoting neuroprotection in animal models of glaucoma.",
keywords = "Brn3b, Gene therapy, Glaucoma, Morrison’s model, Neuroprotection",
author = "Stankowska, {Dorota Luiza} and Minton, {Alena Z.} and Rutledge, {Margaret A.} and Mueller, {Brett H.} and Phatak, {Nitasha R.} and Shaoqing He and Ma, {Hai Ying} and Forster, {Michael J.} and Thomas Yorio and Raghu Krishnamoorthy",
year = "2015",
month = "1",
day = "1",
doi = "10.1167/iovs.14-15008",
language = "English",
volume = "56",
pages = "893--907",
journal = "Investigative Ophthalmology and Visual Science",
issn = "0146-0404",
publisher = "Association for Research in Vision and Ophthalmology Inc.",
number = "2",

}

Neuroprotective effects of transcription factor brn3b in an ocular hypertension rat model of glaucoma. / Stankowska, Dorota Luiza; Minton, Alena Z.; Rutledge, Margaret A.; Mueller, Brett H.; Phatak, Nitasha R.; He, Shaoqing; Ma, Hai Ying; Forster, Michael J.; Yorio, Thomas; Krishnamoorthy, Raghu.

In: Investigative Ophthalmology and Visual Science, Vol. 56, No. 2, 01.01.2015, p. 893-907.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Neuroprotective effects of transcription factor brn3b in an ocular hypertension rat model of glaucoma

AU - Stankowska, Dorota Luiza

AU - Minton, Alena Z.

AU - Rutledge, Margaret A.

AU - Mueller, Brett H.

AU - Phatak, Nitasha R.

AU - He, Shaoqing

AU - Ma, Hai Ying

AU - Forster, Michael J.

AU - Yorio, Thomas

AU - Krishnamoorthy, Raghu

PY - 2015/1/1

Y1 - 2015/1/1

N2 - PURPOSE. Glaucoma is an optic neuropathy commonly associated with elevated intraocular pressure (IOP), leading to optic nerve head (ONH) cupping, axon loss, and apoptosis of retinal ganglion cells (RGCs), which could ultimately result in blindness. Brn3b is a class-4 POU domain transcription factor that plays a key role in RGC development, axon outgrowth, and pathfinding. Previous studies suggest that a decrease in Brn3b levels occurs in animal models of glaucoma. The goal of this study was to determine if adeno-associated virus (AAV)- directed overexpression of the Brn3b protein could have neuroprotective effects following elevated IOP-mediated neurodegeneration.METHODS. Intraocular pressure was elevated in one eye of Brown Norway rats (Rattus norvegicus), following which the IOP-elevated eyes were intravitreally injected with AAV constructs encoding either the GFP (rAAV-CMV-GFP and rAAV-hsyn-GFP) or Brn3b (rAAVCMV- Brn3b and rAAV-hsyn-Brn3b). Retina sections through the ONH were stained for synaptic plasticity markers and neuroprotection was assessed by RGC counts and visual acuity tests.RESULTS. Adeno-associated virus–mediated expression of the Brn3b protein in IOP-elevated rat eyes promoted an upregulation of growth associated protein-43 (GAP-43), actin binding LIM protein (abLIM) and acetylated a-tubulin (ac-Tuba) both posterior to the ONH and in RGCs. The RGC survival as well as axon integrity score were significantly improved in IOP-elevated rAAV-hsyn-Brn3b–injected rats compared with those of the IOP-elevated rAAV-hsyn-GFP-injected rats. Additionally, intravitreal rAAV-hsyn-Brn3b administration significantly restored the visual optomotor response in IOP-elevated rat eyes.CONCLUSIONS. Adeno-associated virus–mediated Brn3b protein expression may be a suitable approach for promoting neuroprotection in animal models of glaucoma.

AB - PURPOSE. Glaucoma is an optic neuropathy commonly associated with elevated intraocular pressure (IOP), leading to optic nerve head (ONH) cupping, axon loss, and apoptosis of retinal ganglion cells (RGCs), which could ultimately result in blindness. Brn3b is a class-4 POU domain transcription factor that plays a key role in RGC development, axon outgrowth, and pathfinding. Previous studies suggest that a decrease in Brn3b levels occurs in animal models of glaucoma. The goal of this study was to determine if adeno-associated virus (AAV)- directed overexpression of the Brn3b protein could have neuroprotective effects following elevated IOP-mediated neurodegeneration.METHODS. Intraocular pressure was elevated in one eye of Brown Norway rats (Rattus norvegicus), following which the IOP-elevated eyes were intravitreally injected with AAV constructs encoding either the GFP (rAAV-CMV-GFP and rAAV-hsyn-GFP) or Brn3b (rAAVCMV- Brn3b and rAAV-hsyn-Brn3b). Retina sections through the ONH were stained for synaptic plasticity markers and neuroprotection was assessed by RGC counts and visual acuity tests.RESULTS. Adeno-associated virus–mediated expression of the Brn3b protein in IOP-elevated rat eyes promoted an upregulation of growth associated protein-43 (GAP-43), actin binding LIM protein (abLIM) and acetylated a-tubulin (ac-Tuba) both posterior to the ONH and in RGCs. The RGC survival as well as axon integrity score were significantly improved in IOP-elevated rAAV-hsyn-Brn3b–injected rats compared with those of the IOP-elevated rAAV-hsyn-GFP-injected rats. Additionally, intravitreal rAAV-hsyn-Brn3b administration significantly restored the visual optomotor response in IOP-elevated rat eyes.CONCLUSIONS. Adeno-associated virus–mediated Brn3b protein expression may be a suitable approach for promoting neuroprotection in animal models of glaucoma.

KW - Brn3b

KW - Gene therapy

KW - Glaucoma

KW - Morrison’s model

KW - Neuroprotection

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U2 - 10.1167/iovs.14-15008

DO - 10.1167/iovs.14-15008

M3 - Article

VL - 56

SP - 893

EP - 907

JO - Investigative Ophthalmology and Visual Science

JF - Investigative Ophthalmology and Visual Science

SN - 0146-0404

IS - 2

ER -