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Jellusova, J.

Publications and source records attributed to Jellusova, J..

2 recordsLinked to original sources

Accumulation of the GSK3 target protein β-catenin is lethal for B cell precursors and malignant B cells

Glycogen synthase kinase 3 (GSK3) is a ubiquitously expressed kinase involved in a myriad of biological processes. Although GSK3 mediated phosphorylation has been shown to induce the degradation of many pro-survival and pro-proliferation factors, cancer cells of different origin show reduced proliferation or survival after GSK3 inhibition. Our current understanding of the role GSK3 plays in normal mature B cells, B cell precursors and transformed B cells is incomplete and does not allow to assess whether GSK3 inhibitors can be used to treat B cell derived malignancies. Here we identify {beta}-catenin as the major factor driving GSK3-inhibition induced changes in B cells. We show that {beta}-catenin accumulation has opposing effects on cell metabolism and survival in mature B cells and B cell precursors. Moreover, we demonstrate that {beta}-catenin destabilizes the commitment to the B cell lineage. In summary, our study identifies {beta}-catenin induced signaling as a factor that can be exploited to limit the survival of malignant B cells.

immunology

CD20 as a gatekeeper of the resting stage of human B cells

CD20 is a B cell specific membrane protein and a target of therapeutic antibodies such as rituximab (RTX)1. In spite of the prominent usage of anti-CD20 antibodies in the clinic little is known about the biological function of CD202. Here we show that CD20 controls the nanoscale organization of receptors on the surface of resting B lymphocytes. A CRISPR/Cas-based ablation of CD20 in Ramos B cells results in a relocalisation of the IgM B cell antigen receptor (IgM-BCR) and the co-receptor CD19. The resulting IgM-BCR/CD19 signaling synapse leads to transient B cell activation followed by plasma cell differentiation. Similarly to CD20-deficient Ramos cells, naive human B cells treated with rituximab in vitro or isolated from patients during rituximab administration display hallmarks of transient activation characterized by the formation of the IgM-BCR/CD19 signaling synapse, followed by CD19 and IgM-BCR downregulation. Moreover, increased expression of specific plasma cell genes can be observed after rituximab treatment in relapsed CLL patients. In summary we identify CD20 as a gatekeeper of the resting state on human B cells and demonstrate that a disruption of the nanoscale organization of the B cell surface via CD20 deletion or anti-CD20 treatment profoundly alters B cell fate.

immunology