TNFAIP8 targets ATG3 to regulate autophagy and participate in the molecular mechanism of ankylosing spondylitis.

Ankylosing spondylitis (AS) is an immune-mediated inflammatory joint disease. This study aims to explore the molecular mechanism by which tumor necrosis factor alpha-induced protein 8 (TNFAIP8) regulates autophagy in AS. We collected 10 mL of peripheral venous blood from 48 patients with AS and 48 healthy controls, along with epidemiological data. The levels of inflammatory cytokines were measured using enzyme-linked immunosorbent assay (ELISA). Then, CD3+ T lymphocytes were isolated via magnetic bead sorting, and the transcriptional levels of TNFAIP8 and autophagy-related genes (ATG3, ATG5, ATG7, ATG12, Beclin1, and LC3B) were determined by real-time quantitative PCR (qRT-PCR). Using small interfering RNA (siRNA) technology, we knocked down TNFAIP8 expression in Jurkat T cells. Next, qRT-PCR and Western blot (WB) were used to detect the mRNA and protein levels of TNFAIP8 as well as the autophagy markers p53, TFEB, ATG3, p62, and LC3. Co-immunoprecipitation (Co-IP) assays confirmed the interaction between TNFAIP8 and ATG3. In T cells from AS patients, TNFAIP8 and ATG3 levels are down-regulated and positively correlated (rs = 0.350, P = 0.015). Further experiments demonstrated that si-TNFAIP8 reduced the mRNA and protein levels of ATG3. Co-IP verified TNFAIP8 interacts with ATG3.TNFAIP8 may regulate AS autophagy by targeting ATG3.