cGAS-STING-NF-κB Axis Mediates Rotenone-Induced NLRP3 Inflammasome Activation Through Mitochondrial DNA Release

Area of Science:

• Immunology
• Cell Biology
• Mitochondrial Biology

Background:

• Rotenone inhibits mitochondrial complex I, causing reactive oxygen species (ROS) production and inflammation.
• The link between mitochondrial dysfunction and inflammatory signaling pathways like the NLRP3 inflammasome is not fully understood.

Purpose of the Study:

• To investigate the role of the cGAS-STING pathway in rotenone-induced NLRP3 inflammasome activation.
• To elucidate the molecular mechanisms connecting mitochondrial dysfunction to inflammation in macrophages.

Main Methods:

• Utilized PMA-differentiated THP-1 macrophages treated with rotenone.
• Assessed cGAS-STING pathway activation via protein expression and phosphorylation (STING, TBK1).
• Measured NF-κB nuclear translocation, NLRP3 inflammasome priming, and IL-1β secretion. Employed STING inhibitor (H-151) and mitochondrial permeability transition pore inhibitor (cyclosporin A).

Main Results:

• Rotenone activated the cGAS-STING pathway, increasing cGAS expression and STING/TBK1 phosphorylation.
• This led to NF-κB nuclear translocation, NLRP3 upregulation, and IL-1β secretion.
• Inhibiting STING or mitochondrial ROS production (via cyclosporin A) attenuated rotenone-induced inflammasome activation and IL-1β release.

Conclusions:

• Rotenone activates the NLRP3 inflammasome through mitochondrial ROS-dependent release of mitochondrial DNA (mtDNA).
• The released mtDNA activates the cGAS-STING-NF-κB signaling axis, leading to inflammasome activation.
• This study reveals a novel mechanism linking mitochondrial dysfunction to innate immune activation via the cGAS-STING pathway.