Can nitroxides evoke the Keap1-Nrf2-ARE pathway in skin?

Area of Science:

• Biochemistry
• Dermatology
• Cell Biology

Background:

• Nitroxides are stable radicals with diverse properties and known protective mechanisms against radical damage.
• They exhibit both nucleophilic and electrophilic characteristics, influencing various cellular pathways.
• Previous research highlighted their antioxidant roles, but a novel skin protection mechanism was investigated.

Purpose of the Study:

• To investigate a novel mechanism of skin protection by nitroxides.
• To explore the role of nitroxides' electrophilic nature in activating cellular defense pathways.
• To demonstrate the efficacy of nitroxides in activating the Keap1-Nrf2-ARE pathway in skin cells.

Main Methods:

• Utilized human keratinocytes (HaCaT) and a human organ culture model.
• Assessed the activation of the Keap1-Nrf2-ARE pathway by nitroxides.
• Compared the potency of oxoammonium cations and hydroxylamines in pathway activation.

Main Results:

• Nitroxides were shown to activate the Keap1-Nrf2-ARE pathway in human skin models.
• This activation occurs through the electrophilic properties of nitroxides.
• Oxoammonium cations demonstrated higher potency than hydroxylamines in activating this pathway.

Conclusions:

• Nitroxides can provide skin protection by activating the Keap1-Nrf2-ARE pathway via their electrophilic nature.
• This finding suggests a new mechanism for nitroxide-based skin protection.
• Understanding this mechanism may lead to expanded use of nitroxides for oxidative stress-related skin conditions.