Sirt2 suppresses inflammatory responses in collagen-induced arthritis

Area of Science:

• Immunology
• Molecular Biology
• Biochemistry

Background:

• Arthritis is a prevalent autoimmune disease causing disability and systemic complications.
• The precise mechanisms driving arthritis pathogenesis remain incompletely understood.
• Sirtuins, a family of NAD(+)-dependent deacetylases, regulate critical cellular processes including inflammation.

Purpose of the Study:

• To investigate the role of Sirtuin 2 (Sirt2) in the development of collagen-induced arthritis (CIA).
• To elucidate the molecular mechanisms by which Sirt2 influences arthritis progression.

Main Methods:

• Utilized in vivo and in vitro models of collagen-induced arthritis (CIA).
• Assessed arthritis severity in wild-type and Sirt2 knockout (Sirt2-KO) mice.
• Analyzed protein and mRNA levels of Sirt2 in joint tissues.
• Investigated the deacetylation activity of Sirt2 on NF-κB pathway components.
• Performed rescue experiments by re-expressing Sirt2 in Sirt2-KO mice.

Main Results:

• Sirt2 protein and mRNA levels were significantly reduced in the joint tissues of mice with CIA.
• Sirt2-KO mice exhibited exacerbated arthritis severity, indicated by clinical scores, paw swelling, and radiological findings.
• Sirt2 was found to deacetylate the p65 subunit of nuclear factor-kappa B (NF-κB) at lysine 310.
• This deacetylation led to decreased expression of key NF-κB-dependent inflammatory genes (IL-1β, IL-6, MCP-1, RANTES, MMP-9, MMP-13).
• Re-expression of Sirt2 in Sirt2-KO mice ameliorated arthritis severity.

Conclusions:

• Sirtuin 2 (Sirt2) acts as a crucial inhibitor in the development of arthritis.
• Sirt2 suppresses arthritis by modulating the NF-κB signaling pathway.
• Targeting Sirt2 may offer a novel therapeutic strategy for managing arthritis.