Cellular antioxidant and reactive oxygen species (ROS) defense systems (ROS/Antioxidant System)

The cellular antioxidant and reactive oxygen species (ROS) defense systems comprise an integrated network of enzymes and non-enzymatic molecules dedicated to maintaining redox homeostasis. Key enzymatic components include superoxide dismutase (SOD), which disproportionates superoxide radicals; catalase and glutathione peroxidase (GPX), which neutralize hydrogen peroxide; and the thioredoxin system (PubMed: 29123456). This system is primarily regulated by the transcription factor Nrf2, which orchestrates the expression of numerous cytoprotective genes in response to oxidative stress (Nature Reviews Drug Discovery: 10.1038/nrd.2017.243). Dysregulation of this system leads to oxidative stress, a state characterized by macromolecular damage to DNA, proteins, and lipids, which is a hallmark of aging, cancer, and neurodegenerative diseases like Parkinson's (NIH: PMC4310836). Pharmacological intervention typically involves either direct ROS scavengers or Nrf2 activators, such as dimethyl fumarate, which are used to mitigate inflammation and tissue damage (StatPearls: NBK547687). However, therapeutic targeting is complex because ROS also serve as essential signaling molecules for cell proliferation and immune response, meaning excessive suppression can disrupt normal physiological processes (PubMed: 24453297). Furthermore, while antioxidants can prevent cancer initiation, they may inadvertently protect established tumor cells from oxidative stress-induced apoptosis. The balance between ROS production and scavenging is therefore critical for cellular health and therapeutic efficacy.

Other names

Redox homeostasis systemAntioxidant defense systemROS scavenging systemOxidative stress response pathway

Activation of the Nrf2-Keap1 signaling pathway to induce phase II antioxidant enzymes, direct neutralization of reactive oxygen species, and replenishment of cellular thiol pools such as glutathione (PubMed: 28267488).