miR-148a controls metabolic programming and survival of mature CD19-negative plasma cells

Long-lived antibody-secreting plasma cells are essential to establish humoral memory against pathogens. While a plasma cell gene signature has been established, elaborate key regulators remain enigmatic.The plasma cell signature microRNA miR-148a favors in vitro differentiation of plasmablasts by repressing the germinal center transcription factor Bach2 and pro-apoptotic BIM and PTEN. To determine whether miR-148a fine-tunescontrols the in vivo development of B cells into long-lived plasma cells, we established mice with a genomic, conditional and inducible deletion of miR-148a. The analysis of miR-148a-deficient mice revealed reduced serum Ig, decreased numbers of newly formed plasmablasts and a reduced CD19-negative, CD93-positive long-lived plasma cells compartment. RNASeq and metabolic analysis showed an impaired glucose uptake and oxidative phosphorylation-based energy metabolism, altered abundance of homing receptors CXCR3 (increase) and CXCR4 (reduction) in miR-148a-deficient plasma cells. These findings establish the importance of miR-148a as a regulator of the differentiation and maintenance of late CD19-negative mature plasma cells by controlling their metabolism and retention in the bone marrow niche. clearly undermine our model of miR-148a as a regulator of the maintenance of long-lived plasma cells. Overall design: RNASeq of WT and miR148a(-/-) bone marrow plasma cells (TACI+ CD138+)