BACH2 in human plasma cell fate decision

We report here the broad transcriptomic program regulated by BACH2 transcription factor. We used a well suited in vitro model of B cell differentiation to evaluate transcriptomic program governed by BACH2 leading to Plasmocyte (PC) differentiation. In this model B cells were cultured with anti-BCR, CpG, CD40L and Interleukin-2 (IL2). This Interleukin triggers PC differentiation by directly repressing BACH2 expression. We artificially inhibit BACH2 expression by siRNA and found that this condition is sufficient to trigger PC differentiation without IL2. To understand global changes induced by enforced BACH2 downregulation we compared Chip-Sequencing data between activated B Cells and BACH2 deficient B cells (siBACH2). We found that BACH2 binds more than 3000 genes across the human genome. RNAsequencing comparing IL2 drivent committed cells and siBACH2 committed cells highlighs a large common trasncriptional program shared by both conditions and involved in B cell destiny. This study provides evidence that BACH2 is a guardian of B cell fate. Differential gene expression data between 3 conditions (RNAsequencing in triplicate) : Uncomitted, comitted, and BACH2-deficient B cells integrated with BACH2 ChipSequencing on human activated B cells versus BACH2 deficient B cells as control.