Reductive stress impairs myoblasts mitochondrial function and triggers mitochondrial hormesis.

Area of Science:

• Mitochondrial biology
• Cellular redox homeostasis
• Pharmacology

Background:

• Oxidative stress is well-documented, but the effects of reductive stress on cellular function are less understood.
• Mitochondrial dysfunction is implicated in various pathologies, and understanding protective mechanisms is crucial.
• Statins can induce cellular damage, necessitating research into protective strategies.

Purpose of the Study:

• To investigate the impact of reductive stress on mitochondrial function.
• To test the hypothesis that reductive stress can trigger mitochondrial hormesis (mitohormesis).
• To determine if mitohormesis can protect mitochondria from the adverse effects of statins.

Main Methods:

• In vitro experiments using L6 myoblasts.
• Exposure to N-acetylcysteine (NAC) to induce reductive stress at various concentrations and time points.
• Assessment of mitochondrial respiration, reactive oxygen species (ROS) production, and mitochondrial biogenesis markers.
• Evaluation of cellular viability and apoptosis following exposure to atorvastatin (ATO) with or without NAC pretreatment.

Main Results:

• Direct NAC exposure induced reductive stress, decreasing mitochondrial respiration and increasing hydrogen peroxide (H₂O₂) production.
• Prolonged NAC exposure (one week) led to mitochondrial adaptation, characterized by reduced ROS, increased mitochondrial content, and enhanced antioxidant capacity.
• Short-term NAC exposure (3 days) did not protect against statin-induced toxicity, whereas one-week NAC pretreatment conferred significant protection against atorvastatin (ATO).

Conclusions:

• Cellular reductive stress can paradoxically activate mitohormesis, a protective adaptive response.
• Preconditioning cells via reductive stress can enhance mitochondrial resilience against drug-induced toxicity, such as that caused by statins.
• These findings elucidate redox-dependent pathways in mitochondria and highlight the potential of mitohormesis as a protective mechanism.