Oxidative stress-induced apoptosis is associated with alterations in mitochondrial caspase activity and Bcl-2-dependent alterations in mitochondrial pH (pHm)

Akiyuki Takahashi, Atsushi Masuda, Mao Sun, Victoria E. Centonze, Brian Herman

Research output: Contribution to journalArticlepeer-review

160 Scopus citations

Abstract

Oxidative stress, the result of cellular production of reactive oxygen species (ROS), has been implicated in a number of diseases of the eye. Exposure of eye tissues (e.g. the cornea and retina) to oxidative stress over time has been hypothesized to underlie the development of age-related macular degeneration (AMD) and maturity onset cataract formation. Light-induced free radicals can damage the eye, and alterations in the antioxidant defenses of the eye have been suggested to play a role in the etiology of glaucoma. Mitochondria are both a major endogenous source and target of ROS, and oxidative stress has been shown to induce apoptotic cell death by targeting the mitochondria directly. Mitochondrial-dependent apoptosis has been shown to require release of cytochrome c from mitochondria and subsequent activation of a specific class of cytoplasmic proteases known as caspases. Bcl-2, an anti-apoptotic protein localized to mitochondria, has been shown to inhibit cytochrome c release and protect against oxidative stress-induced apoptosis. Here we demonstrate that oxidative stress causes activation of mitochondrial matrix caspase-2 and -9 activity that is associated with Bcl-2-inhibitable acidification of mitochondrial pH (pHm). In conjunction with recent reports that caspase activation is maximal at acidic pH, these findings have led us to hypothesize that Bcl-2 may modulate cytochrome c release following oxidative stress by modifying the pH-dependent activation of mitochondrial caspase activity. These studies provide an increased understanding of the mechanism(s) by which oxidative stress damages tissues, and may have important therapeutic implications for treatment of opthamological diseases.

Original languageEnglish (US)
Pages (from-to)497-504
Number of pages8
JournalBrain Research Bulletin
Volume62
Issue number6
DOIs
StatePublished - Feb 15 2004

Keywords

  • Mitochondrial
  • Opthamological diseases
  • pH

Fingerprint Dive into the research topics of 'Oxidative stress-induced apoptosis is associated with alterations in mitochondrial caspase activity and Bcl-2-dependent alterations in mitochondrial pH (pH<sub>m</sub>)'. Together they form a unique fingerprint.

Cite this