[Deubiquitinase MYSM1 Regulates Differentiation of Human B Cells to Plasma Cells].

Objective: To study the regulatory effect of deubiquitinase MYSM1 on differentiation of B cells to plasma cells.

Methods: The interfering and overexpression plasmids of MYSM1 were constructed and then the corresponding lentiviruses were packaged. Human CD19 B cells were isolated from human peripheral blood with Miltenyi B cell isolation kit. Purified CD19 B cells were transduced with lentiviruses and then treated with LPS, the CD138 expression was detected by flow cytometry. The expression of transcription factor was determined by quantitative PCR.

Results: The differentiation of B cells to plasma cells was enhanced after interfering in MYSM1 expression. Quantitative PCR showed that mRNA levels of Pax5 and Bach2 in cells with interfering in MYSM1 were much lower than their counterpart (P＜0.01), and mRNA levels of Prdm1 and Xbp1 in cells with interfering in MYSM1 were much higher than their counterpart (P＜0.01). On the contrary, the differentiation of B cells to plasma cells was inhibited after the overexpression of MYSM1. Quantitative PCR showed that mRNA levels of Pax5 and Bach2 in cells with MYSM1 overexpression were higher than those in control cells (P＜0.01), and mRNA levels of Prdm1 and Xbp1 in cells with MYSM1 overexpression were much lower than those in their counterpart (P＜0.01).

Conclusion: MYSM1 negatively regulates differentiation of human B cells to plasma cells.