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Nitric oxide, mitochondria, and cell death
1Department of Biochemistry, University of Cambridge, United Kingdom. gcb@mole.bio.cam.ac.uk
Abstract:
NO or its derivatives (reactive nitrogen species: RNS) have three types of actions on mitochondria: 1) reversible inhibition of mitochondrial respiration at cytochrome oxidase by NO, and irreversible inhibition at multiple sites by RNS; 2) stimulation of mitochondrial production of superoxide, hydrogen peroxide, and peroxynitrite by NO; and 3) induction of mitochondrial permeability transition (MPT) by RNS. Similarly there are three main roles of mitochondria in NO-induced cell death: a) NO inhibition of respiration can induce necrosis (or excitotoxicity in neurons) and inhibit apoptosis if glycolysis is insufficient to compensate, b) RNS- or oxidant-induced signal transduction or DNA damage may activate the mitochondrial pathway to apoptosis, and c) RNS-induced MPT may induce apoptosis or necrosis.
Insights
Nitric oxide (NO) and reactive nitrogen species (RNS) impact mitochondria by altering respiration, increasing oxidative stress, and inducing mitochondrial permeability transition. These actions influence cell death pathways, including apoptosis and necrosis.
Area of Science:
- Biochemistry
- Cell Biology
- Toxicology
Background:
- Nitric oxide (NO) and reactive nitrogen species (RNS) are critical signaling molecules with complex roles in cellular physiology and pathology.
- Mitochondria are central organelles involved in energy production, signaling, and programmed cell death.
- Understanding the interplay between NO/RNS and mitochondria is crucial for deciphering cell death mechanisms.
Purpose of the Study:
- To elucidate the multifaceted actions of NO and RNS on mitochondrial function.
- To delineate the specific roles of mitochondria in NO- and RNS-mediated cell death.
- To provide a comprehensive overview of NO/RNS-mitochondria interactions in cell death.
Main Methods:
- Review of existing literature on nitric oxide, reactive nitrogen species, and mitochondrial function.
- Analysis of the biochemical mechanisms underlying NO/RNS effects on mitochondrial respiration and MPT.
- Integration of data on mitochondrial roles in apoptosis and necrosis induced by NO/RNS.
Main Results:
- NO reversibly inhibits mitochondrial respiration at cytochrome oxidase, while RNS cause irreversible inhibition.
- NO stimulates mitochondrial production of reactive oxygen species (ROS) and peroxynitrite.
- RNS induce mitochondrial permeability transition (MPT), a key event in cell death.
Conclusions:
- Mitochondrial dysfunction induced by NO/RNS contributes significantly to cell death.
- NO can inhibit apoptosis by impairing respiration, while RNS can trigger apoptosis or necrosis via MPT.
- Mitochondria are key effectors in cell death pathways modulated by NO and RNS.