Role of bax in death of uninfected retinal cells during murine cytomegalovirus retinitis

Juan Mo, Brendan Marshall, Jason Covar, Nancy Y. Zhang, Sylvia B Smith, Sally S. Atherton, Ming Zhang

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Purpose: Extensive death of uninfected bystander neuronal cells is an important component of the pathogenesis of cytomegalovirus retinitis. Our previous results have shown that caspase 3–dependent and –independent pathways are involved in death of uninfected bystander cells during murine cytomegalovirus (MCMV) retinitis and also that Bcl-2, an important inhibitor of apoptosis via the Bax-mediated mitochondrial pathway, is downregulated during this process. The purpose of this study was to determine whether Bax-mediated mitochondrial damage has a significant role in the death of uninfected retinal cells.

Methods: BALB/c mice, Bax−/− mice, or Bax+/+ mice were immunosuppressed with methylprednisolone and infected with 5 × 103 plaque-forming units (PFU) of the K181 strain of MCMV via the supraciliary route. Injected eyes were analyzed by plaque assay, electron microscopy, hematoxylin and eosin (H&E) staining, TUNEL assay, Western blot (for caspase 3, caspase 12, Bax, receptor interacting protein-1 [RIP1] and receptor interacting protein-3 [RIP3]), as well as immunohistochemical staining for MCMV early antigen and cleaved caspase 3.

Results: Significantly more Bax was detected in mitochondrial fractions of MCMV-infected eyes than in mitochondrial fractions of mock-infected control eyes. Furthermore, the level of cleaved caspase 3 was significantly lower in MCMV-infected Bax−/− eyes than in MCMV-infected Bax+/+ eyes. However, more caspase 3–independent cell death of uninfected bystander retinal cells and more cleaved RIP1 were observed in Bax−/− than in Bax+/+ eyes.

Conclusions: During MCMV retinitis, Bax is activated and has an important role in death of uninfected bystander retinal cells by caspase 3–dependent apoptosis. Although the exact mechanism remains to be deciphered, active Bax might also prevent death of some types of uninfected retinal cells by a caspase 3–independent pathway.

Original languageEnglish (US)
Pages (from-to)7137-7146
Number of pages10
JournalInvestigative Ophthalmology and Visual Science
Volume55
Issue number11
DOIs
StatePublished - Sep 23 2014

Fingerprint

Cytomegalovirus Retinitis
Muromegalovirus
Receptor-Interacting Protein Serine-Threonine Kinases
Caspases
Caspase 3
Caspase 12
Apoptosis
Staining and Labeling
Methylprednisolone
In Situ Nick-End Labeling
Hematoxylin
Eosine Yellowish-(YS)
Electron Microscopy
Cell Death
Down-Regulation
Western Blotting

Keywords

  • Apoptosis
  • Bax
  • Murine cytomegalovirus
  • Retinitis

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

Role of bax in death of uninfected retinal cells during murine cytomegalovirus retinitis. / Mo, Juan; Marshall, Brendan; Covar, Jason; Zhang, Nancy Y.; Smith, Sylvia B; Atherton, Sally S.; Zhang, Ming.

In: Investigative Ophthalmology and Visual Science, Vol. 55, No. 11, 23.09.2014, p. 7137-7146.

Research output: Contribution to journalArticle

Mo, Juan ; Marshall, Brendan ; Covar, Jason ; Zhang, Nancy Y. ; Smith, Sylvia B ; Atherton, Sally S. ; Zhang, Ming. / Role of bax in death of uninfected retinal cells during murine cytomegalovirus retinitis. In: Investigative Ophthalmology and Visual Science. 2014 ; Vol. 55, No. 11. pp. 7137-7146.
@article{3f2034c2e32d46e7bf886d2f8a65f08c,
title = "Role of bax in death of uninfected retinal cells during murine cytomegalovirus retinitis",
abstract = "Purpose: Extensive death of uninfected bystander neuronal cells is an important component of the pathogenesis of cytomegalovirus retinitis. Our previous results have shown that caspase 3–dependent and –independent pathways are involved in death of uninfected bystander cells during murine cytomegalovirus (MCMV) retinitis and also that Bcl-2, an important inhibitor of apoptosis via the Bax-mediated mitochondrial pathway, is downregulated during this process. The purpose of this study was to determine whether Bax-mediated mitochondrial damage has a significant role in the death of uninfected retinal cells.Methods: BALB/c mice, Bax−/− mice, or Bax+/+ mice were immunosuppressed with methylprednisolone and infected with 5 × 103 plaque-forming units (PFU) of the K181 strain of MCMV via the supraciliary route. Injected eyes were analyzed by plaque assay, electron microscopy, hematoxylin and eosin (H&E) staining, TUNEL assay, Western blot (for caspase 3, caspase 12, Bax, receptor interacting protein-1 [RIP1] and receptor interacting protein-3 [RIP3]), as well as immunohistochemical staining for MCMV early antigen and cleaved caspase 3.Results: Significantly more Bax was detected in mitochondrial fractions of MCMV-infected eyes than in mitochondrial fractions of mock-infected control eyes. Furthermore, the level of cleaved caspase 3 was significantly lower in MCMV-infected Bax−/− eyes than in MCMV-infected Bax+/+ eyes. However, more caspase 3–independent cell death of uninfected bystander retinal cells and more cleaved RIP1 were observed in Bax−/− than in Bax+/+ eyes.Conclusions: During MCMV retinitis, Bax is activated and has an important role in death of uninfected bystander retinal cells by caspase 3–dependent apoptosis. Although the exact mechanism remains to be deciphered, active Bax might also prevent death of some types of uninfected retinal cells by a caspase 3–independent pathway.",
keywords = "Apoptosis, Bax, Murine cytomegalovirus, Retinitis",
author = "Juan Mo and Brendan Marshall and Jason Covar and Zhang, {Nancy Y.} and Smith, {Sylvia B} and Atherton, {Sally S.} and Ming Zhang",
year = "2014",
month = "9",
day = "23",
doi = "10.1167/iovs.14-15404",
language = "English (US)",
volume = "55",
pages = "7137--7146",
journal = "Investigative Ophthalmology and Visual Science",
issn = "0146-0404",
publisher = "Association for Research in Vision and Ophthalmology Inc.",
number = "11",

}

TY - JOUR

T1 - Role of bax in death of uninfected retinal cells during murine cytomegalovirus retinitis

AU - Mo, Juan

AU - Marshall, Brendan

AU - Covar, Jason

AU - Zhang, Nancy Y.

AU - Smith, Sylvia B

AU - Atherton, Sally S.

AU - Zhang, Ming

PY - 2014/9/23

Y1 - 2014/9/23

N2 - Purpose: Extensive death of uninfected bystander neuronal cells is an important component of the pathogenesis of cytomegalovirus retinitis. Our previous results have shown that caspase 3–dependent and –independent pathways are involved in death of uninfected bystander cells during murine cytomegalovirus (MCMV) retinitis and also that Bcl-2, an important inhibitor of apoptosis via the Bax-mediated mitochondrial pathway, is downregulated during this process. The purpose of this study was to determine whether Bax-mediated mitochondrial damage has a significant role in the death of uninfected retinal cells.Methods: BALB/c mice, Bax−/− mice, or Bax+/+ mice were immunosuppressed with methylprednisolone and infected with 5 × 103 plaque-forming units (PFU) of the K181 strain of MCMV via the supraciliary route. Injected eyes were analyzed by plaque assay, electron microscopy, hematoxylin and eosin (H&E) staining, TUNEL assay, Western blot (for caspase 3, caspase 12, Bax, receptor interacting protein-1 [RIP1] and receptor interacting protein-3 [RIP3]), as well as immunohistochemical staining for MCMV early antigen and cleaved caspase 3.Results: Significantly more Bax was detected in mitochondrial fractions of MCMV-infected eyes than in mitochondrial fractions of mock-infected control eyes. Furthermore, the level of cleaved caspase 3 was significantly lower in MCMV-infected Bax−/− eyes than in MCMV-infected Bax+/+ eyes. However, more caspase 3–independent cell death of uninfected bystander retinal cells and more cleaved RIP1 were observed in Bax−/− than in Bax+/+ eyes.Conclusions: During MCMV retinitis, Bax is activated and has an important role in death of uninfected bystander retinal cells by caspase 3–dependent apoptosis. Although the exact mechanism remains to be deciphered, active Bax might also prevent death of some types of uninfected retinal cells by a caspase 3–independent pathway.

AB - Purpose: Extensive death of uninfected bystander neuronal cells is an important component of the pathogenesis of cytomegalovirus retinitis. Our previous results have shown that caspase 3–dependent and –independent pathways are involved in death of uninfected bystander cells during murine cytomegalovirus (MCMV) retinitis and also that Bcl-2, an important inhibitor of apoptosis via the Bax-mediated mitochondrial pathway, is downregulated during this process. The purpose of this study was to determine whether Bax-mediated mitochondrial damage has a significant role in the death of uninfected retinal cells.Methods: BALB/c mice, Bax−/− mice, or Bax+/+ mice were immunosuppressed with methylprednisolone and infected with 5 × 103 plaque-forming units (PFU) of the K181 strain of MCMV via the supraciliary route. Injected eyes were analyzed by plaque assay, electron microscopy, hematoxylin and eosin (H&E) staining, TUNEL assay, Western blot (for caspase 3, caspase 12, Bax, receptor interacting protein-1 [RIP1] and receptor interacting protein-3 [RIP3]), as well as immunohistochemical staining for MCMV early antigen and cleaved caspase 3.Results: Significantly more Bax was detected in mitochondrial fractions of MCMV-infected eyes than in mitochondrial fractions of mock-infected control eyes. Furthermore, the level of cleaved caspase 3 was significantly lower in MCMV-infected Bax−/− eyes than in MCMV-infected Bax+/+ eyes. However, more caspase 3–independent cell death of uninfected bystander retinal cells and more cleaved RIP1 were observed in Bax−/− than in Bax+/+ eyes.Conclusions: During MCMV retinitis, Bax is activated and has an important role in death of uninfected bystander retinal cells by caspase 3–dependent apoptosis. Although the exact mechanism remains to be deciphered, active Bax might also prevent death of some types of uninfected retinal cells by a caspase 3–independent pathway.

KW - Apoptosis

KW - Bax

KW - Murine cytomegalovirus

KW - Retinitis

UR - http://www.scopus.com/inward/record.url?scp=84910074949&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84910074949&partnerID=8YFLogxK

U2 - 10.1167/iovs.14-15404

DO - 10.1167/iovs.14-15404

M3 - Article

VL - 55

SP - 7137

EP - 7146

JO - Investigative Ophthalmology and Visual Science

JF - Investigative Ophthalmology and Visual Science

SN - 0146-0404

IS - 11

ER -