MicroRNA‑33 regulates the NLRP3 inflammasome signaling pathway in macrophages

Area of Science:

• Immunology
• Molecular Biology
• Metabolic Disease

Background:

• The NLRP3 inflammasome and IL-1β axis are crucial in rheumatoid arthritis (RA) pathogenesis.
• Mitochondrial dysfunction and metabolic dysregulation activate the NLRP3 inflammasome.
• MicroRNA-33 (miR-33) influences lipid metabolism and mitochondrial function.

Purpose of the Study:

• To investigate the role of miR-33 in regulating the NLRP3 inflammasome/IL-1β axis.
• To explore the potential involvement of the miR-33/NLRP3 pathway in rheumatoid arthritis.

Main Methods:

• Utilized miR-33 mimics and anti-miRs in mouse peritoneal macrophages.
• Assessed NLRP3 mRNA and protein expression, caspase-1 activity, and IL-1β secretion.
• Measured mitochondrial oxygen consumption rates and reactive oxygen species (ROS) levels.
• Analyzed miR-33 levels and NLRP3 inflammasome activity in peripheral blood monocytes from RA patients and healthy donors.

Main Results:

• miR-33 significantly upregulated IL-1β expression, NLRP3, and caspase-1 activity in macrophages.
• miR-33 impaired mitochondrial respiration, leading to ROS accumulation, which further activated the NLRP3 inflammasome.
• Elevated miR-33 levels and NLRP3 inflammasome activity were observed in RA patients' monocytes compared to healthy controls.

Conclusions:

• miR-33 acts as a positive regulator of the NLRP3 inflammasome in macrophages.
• The miR-33/NLRP3 inflammasome pathway is implicated in the development of rheumatoid arthritis.
• This pathway represents a potential therapeutic target for RA treatment.