Resting innate-like B cells leverage sustained Notch2/mTORC1 signaling to achieve rapid and mitosis-independent plasma cell differentiation
Brian T. Gaudette, … , Ivan Maillard, David Allman
Brian T. Gaudette, … , Ivan Maillard, David Allman
Published September 2, 2021
Citation Information: J Clin Invest. 2021;131(20):e151975. https://doi.org/10.1172/JCI151975.
View: Text | PDF
Research Article Immunology

Resting innate-like B cells leverage sustained Notch2/mTORC1 signaling to achieve rapid and mitosis-independent plasma cell differentiation

Abstract

Little is known about how cells regulate and integrate distinct biosynthetic pathways governing differentiation and cell division. For B lineage cells it is widely accepted that activated cells must complete several rounds of mitosis before yielding antibody-secreting plasma cells. However, we report that marginal zone (MZ) B cells, innate-like naive B cells known to generate plasma cells rapidly in response to blood-borne bacteria, generate functional plasma cells despite cell-cycle arrest. Further, short-term Notch2 blockade in vivo reversed division-independent differentiation potential and decreased transcript abundance for numerous mTORC1- and Myc-regulated genes. Myc loss compromised plasma cell differentiation for MZ B cells, and reciprocally induced ectopic mTORC1 signaling in follicular B cells enabled division-independent differentiation and plasma cell–affiliated gene expression. We conclude that ongoing in situ Notch2/mTORC1 signaling in MZ B cells establishes a unique cellular state that enables rapid division-independent plasma cell differentiation.

Authors

Brian T. Gaudette, Carly J. Roman, Trini A. Ochoa, Daniela Gómez Atria, Derek D. Jones, Christian W. Siebel, Ivan Maillard, David Allman

×

Figure 6

Sustained Notch2 signaling maintains plasma cell priming.

Options: View larger image (or click on image) Download as PowerPoint
Sustained Notch2 signaling maintains plasma cell priming. C57BL/6 mice w...
C57BL/6 mice were treated with anti–Notch2 (αN2) or isotype control antibody for 48 hours, at which time splenocytes were harvested, CTV-labeled, and sorted MZ B cells stimulated in vitro with CpG plus IL-4/5 for 48 or 72 hours. (A) Cell division and CD138 expression for representative cultures at the indicated time points. (B) CD138 surface expression as a function of division number at 72 hours for stimulated MZ or FO B cells from the indicated treatment groups. Shown are mean and SEM for the percentage of all viable CD138+ cells at the indicated division number. **P < 0.01, ***P < 0.001. (C) Summary data cultures derived from 3 animals per treatment are shown as the mean and SEM for each given condition (individual values, ***P < 0.001, 2-way ANOVA, Sidak’s multiple comparison test between antibody treatment groups). (D) Graded numbers of CD138+ cells generated with the indicated stimuli were sorted into ELISpot assays to quantify functional ASCs using 3 to 4 wells/condition. PD indicates PD0332991. Shown are mean and SEM (individual values, *P < 0.05, 2-way ANOVA, Sidak’s multiple comparison test between antibody treatment groups). (E) Representative wells from D for undivided and cells versus cells that had experienced at least one division after stimulation with CpG plus IL-4/5 with or without PD. Data are compiled from 4 animal replicates per group and time point.