Knockdown of RSAD2 attenuates B cell hyperactivity in patients with primary Sjögren's syndrome (pSS) via suppressing NF-κb signaling pathway.

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease that is mainly characterized as abnormal activation of B cells. It is reported that radical s-adenosyl methionine domain-containing 2 (RSAD2) is overexpressed in CD19+ B cells of pSS patients, but its role in pSS B cells remains unknown. Herein, RSAD2 expression was upregulated in CD19+ B cells of pSS patients and positively correlated with the expression of interleukin-10 (IL-10) in serum. After CD40L stimulation, knockdown of RSAD2 significantly attenuated cell viability, the production levels of immunoglobins and the expression of IL-10, while promoted cell apoptosis of pSS CD19+ B cells. Mechanistically, knockdown of RSAD2 negatively regulated nuclear factor kappa-b (NF-κb) signaling pathway. In addition, overexpression of p65 prominently alleviated the inhibitory effect of RSAD2 knockdown on proliferation, immunoglobin production and IL-10 expression in CD40L-induced CD19+ B cells. Our study indicated that silencing RSAD2 attenuated pSS B cell hyperactivity via suppressing NF-κb signaling pathway, which might provide a potential therapeutic target for pSS treatment.