Mitochondrial dysfunction promotes and aggravates the inflammatory response in normal human synoviocytes.

Area of Science:

• Rheumatology
• Cell Biology
• Mitochondrial Biology

Background:

• Synoviocytes in rheumatoid arthritis (RA) contribute to pathogenesis via oxidative stress and mitochondrial alterations.
• Investigating the role of mitochondrial dysfunction in inducing inflammatory responses in normal human synoviocytes is crucial for understanding RA.

Purpose of the Study:

• To determine if mitochondrial dysfunction induces inflammatory responses in cultured normal human synoviocytes.
• To elucidate the pathways involved, including reactive oxygen species (ROS) and nuclear factor-kappa B (NF-κB) activation.
• To evaluate the potential of resveratrol as an anti-inflammatory agent.

Main Methods:

• Mitochondrial dysfunction was induced using oligomycin, antimycin A, and paraquat.
• Inflammatory mediators (COX-2, PGE2, IL-8), ROS production, and NF-κB activation were assessed.
• ROS scavengers (N-acetylcysteine, mitoTEMPO) and an NF-κB inhibitor (BAY-117085) were employed to study pathways. Resveratrol was also tested.

Main Results:

• Mitochondrial dysfunction alone increased mitochondrial ROS, COX-2, PGE2, and IL-8 expression.
• Oligomycin-induced dysfunction synergized with IL-1β to amplify inflammatory mediator expression.
• The inflammatory effects were dependent on ROS production and NF-κB activation, as interventions targeting these pathways reduced inflammation. Resveratrol decreased ROS and NF-κB activation.

Conclusions:

• Mitochondrial dysfunction can induce and sensitize synoviocytes, amplifying IL-1β-induced inflammation.
• This suggests a significant role for mitochondrial dysfunction in RA pathogenesis.
• Resveratrol demonstrates potential as a therapeutic strategy for controlling synovial inflammation in RA.