Frontiers in Immunology (Feb 2015)

Distinct transcriptomic features are associated with transitional and mature B-cell populations in the mouse spleen

  • Eden eKleiman,
  • Daria eSalyakina,
  • Magali eDe Heusch,
  • Magali eDe Heusch,
  • Kristen L Hoek,
  • Joan M Llanes,
  • Iris eCastro,
  • Jacqueline A Wright,
  • Emily S Clark,
  • Derek Michael Dykxhoorn,
  • Akiko eTakeda,
  • Enrico eCapobianco,
  • Jean-Christophe eRenauld,
  • Jean-Christophe eRenauld,
  • Wasif N Khan

DOI
https://doi.org/10.3389/fimmu.2015.00030
Journal volume & issue
Vol. 6

Abstract

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Splenic transitional B-cells (T1 and T2) are selected to avoid self-reactivity and to safeguard against autoimmunity, then differentiate into mature follicular (FO-I and FO-II) and marginal zone (MZ) subsets. Transcriptomic analysis by RNA-seq of the five B-cell subsets revealed T1 cell signature genes included RAG suggesting a potential for receptor revision. T1 to T2 B-cell differentiation was marked by a switch from Myb to Myc, increased expression of the PI3K adapter DAP10 and MHC class II. FO-II may be an intermediate in FO-I differentiation and may also become MZ B-cells as suggested by principal component analysis (PCA). MZ B-cells possessed the most distinct transcriptome including downregulation of CD45 phosphatase-associated protein (CD45-AP/PTPRC-AP), as well as upregulation of IL-9R and innate molecules TLR3, TLR7 and bactericidal Perforin-2 (MPEG1). Among the endosomal TLRs, stimulation via TLR3 further enhanced Perforin-2 expression exclusively in MZ B-cells. Using gene-deleted and overexpressing transgenic mice we show that IL-9/IL-9R interaction resulted in rapid activation of STAT1, 3 and 5, primarily in MZ B-cells. Importantly, CD45-AP mutant mice had reduced transitional and increased mature MZ and FO B-cells, suggesting that it prevents premature entry of transitional B-cells to the mature B-cell pool or their survival and proliferation. Together, these findings suggest, developmental plasticity among splenic B-cell subsets, potential for receptor revision in peripheral tolerance whereas enhanced metabolism coincides with T2 to mature B-cell differentiation. Further, unique core transcriptional signatures in MZ B-cells may control their innate features.

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