The cellular basis for diverse responses to oxygen.

Area of Science:

• Cellular Biology
• Physiology

Background:

• Mammalian cells exhibit distinct responses to varying oxygen concentrations.
• Low oxygen (hypoxia) activates hypoxia-inducible factor-1 (HIF-1), promoting adaptation without senescence, cell death, or ATP depletion.
• High oxygen (hyperoxia) induces senescence, cell death, and reduced ATP levels, without HIF-1 activation.

Purpose of the Study:

• To review the role of mitochondrial-derived reactive oxygen species (ROS) in mediating cellular responses to both hypoxia and hyperoxia.
• To highlight the common signaling pathway involving mitochondrial ROS despite divergent cellular outcomes.

Main Methods:

• This is a perspective review, synthesizing existing research.
• Focuses on the signaling mechanisms of mitochondrial ROS under different oxygen conditions.

Main Results:

• Mitochondrial ROS generation is a common signaling mechanism in both hypoxic and hyperoxic environments.
• Despite different outcomes (adaptation vs. senescence/death), mitochondrial ROS plays a critical role in both scenarios.

Conclusions:

• Mitochondrial ROS signaling is a key determinant of cellular fate under varying oxygen levels.
• Understanding this pathway is crucial for comprehending cellular adaptation and stress responses.