Activation of the mitochondrial caspase pathway and subsequent calpain activation in monkey RPE cells cultured under zinc depletion

E. Nakajima, K. B. Hammond, Thomas (Tom) Shearer, M. Azuma

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

PurposeDecreased zinc levels in the macula are reported in patients with age-related macular degeneration, and the zinc chelator N,N,N',N′-tetrakis (2- pyridylmethyl) ethylenediamine) (TPEN) causes death of human retinal pigment epithelial (RPE) cells. The purpose of the present study was to investigate signal transduction pathways during cell death initiated by TPEN, using monkey RPE cells.MethodsRPE cells were cultured with TPEN. Activation of calpains and caspases, and proteolysis of their substrates were detected by immunoblotting. Incubation of calpain inhibitor SNJ-1945 or caspase inhibitor z-VAD-fmk was used to confirm activation of specific proteases.ResultsTPEN caused a time-dependent decrease in viable RPE cells. Cell death was accompanied by activation of calpain-1, caspase-9, and caspase-3. SNJ-1945 inhibited calpain activation and slightly inhibited caspase-9 activation. z-VAD-fmk inhibited caspases and calpain-1 activation. TPEN did not activate caspase-12.ConclusionsRelative zinc deficiency in RPE cells causes activation of cytosolic calpain and mitochondrial caspase pathways without ER stress.

Original languageEnglish (US)
Pages (from-to)85-92
Number of pages8
JournalEye (Basingstoke)
Volume28
Issue number1
DOIs
StatePublished - Jan 2014

Fingerprint

ethylenediamine
Calpain
Retinal Pigments
Caspases
Haplorhini
Zinc
Epithelial Cells
Caspase 9
Cell Death
Caspase 12
Caspase 1
Caspase Inhibitors
Macular Degeneration
Chelating Agents
Immunoblotting
Caspase 3
Proteolysis
Cause of Death
Cultured Cells
Signal Transduction

Keywords

  • AMD
  • calpain
  • caspase
  • monkey
  • non-human primate
  • zinc depletion

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Activation of the mitochondrial caspase pathway and subsequent calpain activation in monkey RPE cells cultured under zinc depletion. / Nakajima, E.; Hammond, K. B.; Shearer, Thomas (Tom); Azuma, M.

In: Eye (Basingstoke), Vol. 28, No. 1, 01.2014, p. 85-92.

Research output: Contribution to journalArticle

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AU - Shearer, Thomas (Tom)

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N2 - PurposeDecreased zinc levels in the macula are reported in patients with age-related macular degeneration, and the zinc chelator N,N,N',N′-tetrakis (2- pyridylmethyl) ethylenediamine) (TPEN) causes death of human retinal pigment epithelial (RPE) cells. The purpose of the present study was to investigate signal transduction pathways during cell death initiated by TPEN, using monkey RPE cells.MethodsRPE cells were cultured with TPEN. Activation of calpains and caspases, and proteolysis of their substrates were detected by immunoblotting. Incubation of calpain inhibitor SNJ-1945 or caspase inhibitor z-VAD-fmk was used to confirm activation of specific proteases.ResultsTPEN caused a time-dependent decrease in viable RPE cells. Cell death was accompanied by activation of calpain-1, caspase-9, and caspase-3. SNJ-1945 inhibited calpain activation and slightly inhibited caspase-9 activation. z-VAD-fmk inhibited caspases and calpain-1 activation. TPEN did not activate caspase-12.ConclusionsRelative zinc deficiency in RPE cells causes activation of cytosolic calpain and mitochondrial caspase pathways without ER stress.

AB - PurposeDecreased zinc levels in the macula are reported in patients with age-related macular degeneration, and the zinc chelator N,N,N',N′-tetrakis (2- pyridylmethyl) ethylenediamine) (TPEN) causes death of human retinal pigment epithelial (RPE) cells. The purpose of the present study was to investigate signal transduction pathways during cell death initiated by TPEN, using monkey RPE cells.MethodsRPE cells were cultured with TPEN. Activation of calpains and caspases, and proteolysis of their substrates were detected by immunoblotting. Incubation of calpain inhibitor SNJ-1945 or caspase inhibitor z-VAD-fmk was used to confirm activation of specific proteases.ResultsTPEN caused a time-dependent decrease in viable RPE cells. Cell death was accompanied by activation of calpain-1, caspase-9, and caspase-3. SNJ-1945 inhibited calpain activation and slightly inhibited caspase-9 activation. z-VAD-fmk inhibited caspases and calpain-1 activation. TPEN did not activate caspase-12.ConclusionsRelative zinc deficiency in RPE cells causes activation of cytosolic calpain and mitochondrial caspase pathways without ER stress.

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