Inhibition of B lymphocyte-induced maturation protein-1 reduces the production of autoantibody and alleviates symptoms of systemic lupus erythematosus.

The B lymphocyte-induced maturation protein-1 (Blimp-1) is an important transcription factor for the maintenance of antigen-specific immune responses, and it is crucial in the development of systemic lupus erythematosus (SLE). This study aimed to investigate the role of Blimp-1 in the development of SLE and autoimmune-like symptoms. Lentivirus-mediated Blimp-1 siRNA was constructed and injected into MRL-Fas(lpr) lupus mice. The expression levels of Blimp-1, J-chain, C-myc, XBP-1 and BCMA in peripheral blood mononuclear cells (PMBCs) were determined by RT-PCR. Anti-dsDNA autoantibody levels were detected using ELISA. The expression levels of Blimp-1 in liver, kidney, spleen and lymph nodes of mice were also detected by Western blot. The 24-h urinary protein was monitored weekly. Our results demonstrated that in MRL-Fas(lpr) lupus mice, Blimp-1 was upregulated in PMBCs, liver, kidney, spleen and lymph nodes. Administration of Blimp-1 siRNA reduced the expression of Blimp-1 and the anti-dsDNA level by 78 and 28%, respectively, in the peripheral blood, and the expression of XBP-1, J-chain and BCMA was also decreased. Although the Blimp-1 level in liver showed no significant changes, the levels of Blimp-1 in kidney, spleen and lymph nodes were dramatically decreased by 95, 72 and 47%, respectively. Kidney diseases induced by SLE in lupus mice were mitigated, and urinary protein levels were significantly decreased. These results indicate that Blimp-1 plays an important role in promoting the progression of SLE. Therefore, Blimp-1 may provide a new therapeutic target in the treatment of SLE.