IĸBζ as a Central Modulator of Inflammatory Arthritis Pathogenesis.

Area of Science:

• Immunology
• Molecular Biology
• Rheumatology

Background:

• Current inflammatory arthritis therapies have variable efficacy and side effects.
• Nuclear factor-kappa B (NF-ĸB) is crucial for inflammatory cytokine production but essential for physiological processes.
• Targeting downstream pathways of NF-ĸB selectively controlling inflammatory cytokines is advantageous.

Purpose of the Study:

• To investigate the role of IĸBζ, an inflammatory signature of NF-ĸB, in inflammatory arthritis.
• To evaluate IĸBζ as a potential therapeutic target for rheumatoid arthritis.

Main Methods:

• Generated mice with myeloid, lymphoid, and global deletion of Nfkbiz (gene encoding IĸBζ).
• Induced serum transfer-induced arthritis in these models.
• Administered pharmacologic inhibitors of IĸBζ, including dimethyl itaconate (DI) and 8-hydroxyquinoline (HQ).
• Analyzed synovial tissue using various techniques including immunohistochemistry and flow cytometry.

Main Results:

• Global deletion of Nfkbiz ameliorated experimental inflammatory arthritis by reducing inflammatory cells and increasing anti-inflammatory/regenerative cells.
• Expression of immune responsive gene-1 and itaconate production were increased.
• Dimethyl itaconate (DI) and 8-hydroxyquinoline (HQ) inhibited IĸBζ-mediated inflammatory factors and reduced joint swelling and damage in vivo.
• IĸBζ inhibition spared beneficial NF-ĸB functions.

Conclusions:

• IĸBζ is a specific therapeutic target for inflammatory arthritis, including rheumatoid arthritis.
• Inhibition of IĸBζ offers a promising strategy by selectively targeting pathological inflammation while preserving essential physiological functions.