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PDK1 orchestrates early NK cell development through induction of E4BP4 expression and maintenance of IL-15 responsiveness.

Yang M, Li D, Chang Z, Yang Z, Tian Z, Dong Z - J. Exp. Med. (2015)

Bottom Line: It remains largely unknown which signal is required to induce E4BP4 expression and what effects it has during NK cell differentiation.Thus, we identify a role for PDK1 signaling as a key mediator in regulating E4BP4 expression during early NK cell development.Our findings underscore the importance of IL-15 self-responsiveness through a positive feedback loop that involves PDK1-mTOR-E4BP4-CD122 signaling.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Medicine, and Center of Animal Facility, Tsinghua University, Beijing 100086, China.

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Ectopic expression of E4BP4 or Eomes rescues PDK1-deficient NK cell development. (A) PDK1fl/fl and PDK1fl/fl/Vav1-Cre+ mice were treated with 5-FU for 4 d, and bone marrow cells were collected for spin infection with MSCV retrovirus encoding control GFP, E4BP4, or Eomes, respectively. The infected BM cells were then transferred into RAG1−/−γc− mice. After 6 wk, CD122 versus NK1.1 expression on gated CD3− cells was analyzed by flow cytometry. The numbers in the outlined areas indicate the percent of CD3− cells. (B) Percentages of CD3−CD122+NK1.1+ and CD3−CD122−NK1.1int were enumerated as shown. Data were pooled from three independent experiments. n = 5–7. *, P < 0.05; **, P < 0.005.
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fig4: Ectopic expression of E4BP4 or Eomes rescues PDK1-deficient NK cell development. (A) PDK1fl/fl and PDK1fl/fl/Vav1-Cre+ mice were treated with 5-FU for 4 d, and bone marrow cells were collected for spin infection with MSCV retrovirus encoding control GFP, E4BP4, or Eomes, respectively. The infected BM cells were then transferred into RAG1−/−γc− mice. After 6 wk, CD122 versus NK1.1 expression on gated CD3− cells was analyzed by flow cytometry. The numbers in the outlined areas indicate the percent of CD3− cells. (B) Percentages of CD3−CD122+NK1.1+ and CD3−CD122−NK1.1int were enumerated as shown. Data were pooled from three independent experiments. n = 5–7. *, P < 0.05; **, P < 0.005.

Mentions: To investigate whether the compromised NK cell development and low expression level of CD122 correlated with less E4BP4 induction by IL-15 in PDK1−/− mice, actively dividing PDK1−/− bone marrow cells with enriched HSCs were infected by retroviruses encoding E4BP4 or Eomes. 6 wk after in vivo differentiation, exogenous expression of E4BP4 gave rise to an increase in the NK cell population in PDK1-intact bone marrow group, as reported elsewhere (Fig. 4, A and B; Gascoyne et al., 2009). Importantly, ectopic expression of E4BP4 in PDK1−/− bone marrow cells could recover the CD122+NK1.1+ NK cell population to a great extent (Fig. 4 A, B). Likewise, exogenous E4BP4 expression heightened the expression level of CD122 on PDK1−/− NK cells and prevented the accumulation of the arrested NK1.1int CD122− NK cells in the PDK1−/− bone marrow. Similar results were also obtained when Eomes was ectopically expressed (Fig. 4, A and B). Therefore, the impaired NK cell development in PDK1-deficient mice is largely caused by the defect in E4BP4 induction by IL-15.


PDK1 orchestrates early NK cell development through induction of E4BP4 expression and maintenance of IL-15 responsiveness.

Yang M, Li D, Chang Z, Yang Z, Tian Z, Dong Z - J. Exp. Med. (2015)

Ectopic expression of E4BP4 or Eomes rescues PDK1-deficient NK cell development. (A) PDK1fl/fl and PDK1fl/fl/Vav1-Cre+ mice were treated with 5-FU for 4 d, and bone marrow cells were collected for spin infection with MSCV retrovirus encoding control GFP, E4BP4, or Eomes, respectively. The infected BM cells were then transferred into RAG1−/−γc− mice. After 6 wk, CD122 versus NK1.1 expression on gated CD3− cells was analyzed by flow cytometry. The numbers in the outlined areas indicate the percent of CD3− cells. (B) Percentages of CD3−CD122+NK1.1+ and CD3−CD122−NK1.1int were enumerated as shown. Data were pooled from three independent experiments. n = 5–7. *, P < 0.05; **, P < 0.005.
© Copyright Policy - openaccess
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4322053&req=5

fig4: Ectopic expression of E4BP4 or Eomes rescues PDK1-deficient NK cell development. (A) PDK1fl/fl and PDK1fl/fl/Vav1-Cre+ mice were treated with 5-FU for 4 d, and bone marrow cells were collected for spin infection with MSCV retrovirus encoding control GFP, E4BP4, or Eomes, respectively. The infected BM cells were then transferred into RAG1−/−γc− mice. After 6 wk, CD122 versus NK1.1 expression on gated CD3− cells was analyzed by flow cytometry. The numbers in the outlined areas indicate the percent of CD3− cells. (B) Percentages of CD3−CD122+NK1.1+ and CD3−CD122−NK1.1int were enumerated as shown. Data were pooled from three independent experiments. n = 5–7. *, P < 0.05; **, P < 0.005.
Mentions: To investigate whether the compromised NK cell development and low expression level of CD122 correlated with less E4BP4 induction by IL-15 in PDK1−/− mice, actively dividing PDK1−/− bone marrow cells with enriched HSCs were infected by retroviruses encoding E4BP4 or Eomes. 6 wk after in vivo differentiation, exogenous expression of E4BP4 gave rise to an increase in the NK cell population in PDK1-intact bone marrow group, as reported elsewhere (Fig. 4, A and B; Gascoyne et al., 2009). Importantly, ectopic expression of E4BP4 in PDK1−/− bone marrow cells could recover the CD122+NK1.1+ NK cell population to a great extent (Fig. 4 A, B). Likewise, exogenous E4BP4 expression heightened the expression level of CD122 on PDK1−/− NK cells and prevented the accumulation of the arrested NK1.1int CD122− NK cells in the PDK1−/− bone marrow. Similar results were also obtained when Eomes was ectopically expressed (Fig. 4, A and B). Therefore, the impaired NK cell development in PDK1-deficient mice is largely caused by the defect in E4BP4 induction by IL-15.

Bottom Line: It remains largely unknown which signal is required to induce E4BP4 expression and what effects it has during NK cell differentiation.Thus, we identify a role for PDK1 signaling as a key mediator in regulating E4BP4 expression during early NK cell development.Our findings underscore the importance of IL-15 self-responsiveness through a positive feedback loop that involves PDK1-mTOR-E4BP4-CD122 signaling.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Medicine, and Center of Animal Facility, Tsinghua University, Beijing 100086, China.

Show MeSH
Related in: MedlinePlus