B-cell Division RNA-seq [RNA-Seq]

B cells provide humoral immunity by differentiating into antibody secreting plasma cells. Differentiation is dependent upon division and transcriptional changes, with commitment to B cell lineages associated with epigenetic changes. Analysis of early transcriptional and epigenetic events in B cell differentiation revealed that plasmablasts and plasma cells undergo dynamic changes in gene expression and a progressive DNA hypomethylation targeted to at least 10% of genes/loci. Of the differentially methylated loci, more than 99.7% were demethylated during differentiation and these clustered in cis-regulatory features such as enhancers and transcription factor binding sites. Changes in gene expression and DNA methylation coincided with each other at specific divisions during differentiation and inhibition of DNA methylation resulted in augmented plasma cell commitment in a division-dependent manner. These data identify a major epigenetic reprogramming event during early B cell differentiation coupled division and provide an approach to modulating humoral immune responses. Overall design: Splenic B cells (B220+ CD43-) from naïve C57/BL6J mice were labeled with CFSE or CTV and transferred into uMT mice and allowed to rest overnight prior to challenge with LPS. Three days post challenge adoptively transferred B cells representing distinct divisions were sorted out for molecular analysis. These divisions are labelled Div0, Div1, Div3, Div5, Div8- and Div8+. Division 8- refers to cells that divided at least 8 times but were CD138-, whereas Division 8+ refers to cells that divided at least 8 times but were CD138+. Cells were subjected to RNA-seq and Reduced Representation Bisulfite Sequencing.

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Barwick BG, Scharer CD, Bally APR, Boss JM