1. Expression of S100A8 protein on B cells is associated with disease activity in patients with systemic lupus erythematosus
- Author
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Koji Kitagori, Takuma Oku, Masaki Wakabayashi, Tomoya Nakajima, Ran Nakashima, Kosaku Murakami, Yoshitaka Hirayama, Yasushi Ishihama, Koichiro Ohmura, Akio Morinobu, Tsuneyo Mimori, and Hajime Yoshifuji
- Subjects
Systemic lupus erythematosus ,B cells ,S100A8 ,Diseases of the musculoskeletal system ,RC925-935 - Abstract
Abstract Background Systemic lupus erythematosus (SLE) is an intractable disease characterized by autoantibody production and autoreactive B and T cell proliferation. Although several studies have revealed multiple genetic and environmental associations, the underlying mechanisms remain unknown. Methods We performed proteomics and transcriptomics using liquid chromatography-mass spectrometry and DNA microarray, using peripheral blood B cells from patients with SLE, and healthy controls (HC). We explored molecules associated with the pathophysiology of SLE by flow cytometry and B cell stimulation assay. Results We identified for the first time that expression of both S100A8 protein and mRNA were markedly upregulated in SLE B cells. The results obtained using flow cytometry showed that S100A8 was highly expressed on the surface of B cells of patients with active SLE (MFI; HC 102.5 ± 5.97, stable SLE 111.4 ± 12.87, active SLE 586.9 ± 142.9), and S100A8 on the cell surface was decreased after treatment (MFI; pre-treat 1094.5 ± 355.38, post-treat 492.25 ± 247.39); therefore, it is suggested that S100A8 may be a marker for disease activity. The mRNA expression of S100A8 was particularly upregulated in memory B cells of SLE (56.68 fold higher than HC), suggesting that S100A8 may be mainly secreted by memory B cells in the pathogenesis of SLE. Conclusions Our results imply that the S100A8 proteins secreted from memory B cells may stimulate granulocytes and monocytes through pattern recognition receptors, activate the innate immune system, and are involved in the pathogenesis of SLE.
- Published
- 2023
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