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 4

Notch/IL-21 coculture increases production of T cell–primed progenitors.

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Notch/IL-21 coculture increases production of T cell–primed progenitors....
(A) Sorted BM LSK cells were cultured 2 weeks on OP9-Dll1 cells with indicated cytokines. (B) Representative flow plot for T cell developmental markers on WT LSK cells cultured 2 weeks on OP9-Dll1 cells with or without IL-21, gated on live cells. (C) Cell count after 2 weeks’ coculture of WT (n = 8) or IL21r-KO (n = 6) LSK cells on OP9-Dll1, with or without IL-21. Data generated using individual mice. (D) Absolute number of DN2 (n = 8) (CD44+CD25+) and DN3 (n = 8) (CD44–CD25+) cells generated after 2 weeks of OP9-Dll1 coculture, with or without IL-21. Data generated using individual mice. (E) Representative histograms of p-Thr202/Tyr204 ERK, p-Ser727 STAT1, and p-Tyr705 STAT3 of 1-week OP9-Dll1 cultured LSK cells after 30-minute treatment of vehicle or IL-21. Gray/filled = control, black/empty = IL-21. (F) Fold change in MFI normalized to control for p-Thr202/Tyr204 ERK (n = 4), p-Ser727 STAT1 (n = 3), and p-Tyr705 STAT3 (n = 4) of 1-week OP9-Dll1 cultured LSK cells with or without 30-minute IL-21 treatment. Data generated using individual mice. (G) Sorted BM LSK cells were cultured on plates with immobilized rhDll4 and rhVCAM-1 with indicated cytokines. (H) Representative flow plot for T cell developmental markers on WT LSK cells cultured 12 days on immobilized rhDll4 and rhVCAM-1 with or without IL-21, gated on live cells. (I) Cell count after 12 days’ culture of WT (n = 3) sorted LSK cells on immobilized rhDll4 and rhVCAM-1 with or without IL-21. Data generated using individual mice. (J) Absolute number of DN2 (CD44+CD25+) and DN3 (CD44–CD25+) cells generated after 12 days of culture on immobilized rhDll4 and rhVCAM-1, with or without IL-21. Data generated using individual mice. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. Statistical analysis performed using Student’s 2-tailed t test (D, I, and J) and 2-way ANOVA (C and F). rh, recombinant human.