A Notch/IL-21 signaling axis primes bone marrow T cell progenitor expansion
Kilian Sottoriva, Na Yoon Paik, Zachary White, Thilinie Bandara, Lijian Shao, Teruyuki Sano, Kostandin V. Pajcini
Kilian Sottoriva, Na Yoon Paik, Zachary White, Thilinie Bandara, Lijian Shao, Teruyuki Sano, Kostandin V. Pajcini
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Research Article Hematology Transplantation

A Notch/IL-21 signaling axis primes bone marrow T cell progenitor expansion

Abstract

Long-term impairment in T cell–mediated adaptive immunity is a major clinical obstacle following treatment of blood disorders with hematopoietic stem cell transplantation. Although T cell development in the thymus has been extensively characterized, there are significant gaps in our understanding of prethymic processes that influence early T cell potential. We have uncovered a Notch/IL-21 signaling axis in bone marrow common lymphoid progenitor (CLP) cells. IL-21 receptor expression was driven by Notch activation in CLPs, and in vivo treatment with IL-21 induced Notch-dependent CLP proliferation. Taking advantage of this potentially novel signaling axis, we generated T cell progenitors ex vivo, which improved repopulation of the thymus and peripheral lymphoid organs of mice in an allogeneic transplant model. Importantly, Notch and IL-21 activation were equally effective in the priming and expansion of human cord blood cells toward the T cell fate, confirming the translational potential of the combined treatment.

Authors

Kilian Sottoriva, Na Yoon Paik, Zachary White, Thilinie Bandara, Lijian Shao, Teruyuki Sano, Kostandin V. Pajcini

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Figure 1

Notch signaling hypomorph reveals CLP defect in the BM.

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Notch signaling hypomorph reveals CLP defect in the BM. (A) Notch1ΔTAD i...
(A) Notch1ΔTAD interferes with Notch1 by forming a trimolecular complex with RBPj and MAML but weakly activating transcription without TAD domain–dependent coactivator recruitment. (B) Representative flow plot for CLPs (CD135+Sca1lo), gated on Lin–cKitloCD127+, with percentage of live cells indicated. (C) Absolute number of BM CLP cells in WT (n = 6), Notch1+/– (n = 3), and Notch1+/ΔTAD (n =6). (D) (Top) Representative histogram for Ly6D expression on CLPs, gated on Lin–cKitloCD127+CD135+Sca1lo. (Bottom) Absolute number of Ly6D– BM CLP cells in WT (n = 4) and Notch1+/ΔTAD (n = 4). (E) Differential gene expression shown as Z score heatmap determined by RNA-Seq of mRNA isolated from WT (n = 5), Notch1+/– (n = 5), and Notch1+/ΔTAD CLPs (n = 3). (Right) Select list of differentially expressed genes. (F) Expression of Deptor relative to EF1α normalized to WT determined by qRT-PCR of mRNA isolated from CLPs sorted from WT (n = 5) and Notch1+/ΔTAD (n = 5) mice. (G) Expression of IL21r relative to EF1α normalized to WT determined by qRT-PCR of mRNA isolated from CLPs sorted from WT (n = 5) and Notch1+/ΔTAD (n = 5) mice. *P < 0.05, **P < 0.01, ***P < 0.001. Statistical analysis performed using Student’s 2-tailed t test (D, F, and G) and 1-way ANOVA (C).