The Transcription Factor ZNF683/HOBIT Regulates Human NK-Cell Development.

Mirte Post,Angelica Cuapio,Jan Spanholtz,Emilio Casanova,Dorit Lehmann,Martin Bilban,Ulrike Resch,David M Davies,Bernhard Schlechta,Dagmar Stoiber,Wolfgang Eppel,Amit Nathwani,Markus Osl,Erhard Hofer

doi:10.3389/fimmu.2017.00535

Abstract

We identified ZNF683/HOBIT as the most highly upregulated transcription factor gene during ex vivo differentiation of human CD34+ cord blood progenitor cells to CD56+ natural killer (NK) cells. ZNF683/HOBIT mRNA was preferentially expressed in NK cells compared to other human peripheral blood lymphocytes and monocytes. During ex vivo differentiation, ZNF683/HOBIT mRNA started to increase shortly after addition of IL-15 and further accumulated in parallel to the generation of CD56+ NK cells. shRNA-mediated knockdown of ZNF683/HOBIT resulted in a substantial reduction of CD56−CD14− NK-cell progenitors and the following generation of CD56+ NK cells was largely abrogated. The few CD56+ NK cells, which escaped the developmental inhibition in the ZNF683/HOBIT knockdown cultures, displayed normal levels of NKG2A and KIR receptors. Functional analyses of these cells showed no differences in degranulation capacity from control cultures. However, the proportion of IFN-γ-producing cells appeared to be increased upon ZNF683/HOBIT knockdown. These results indicate a key role of ZNF683/HOBIT for the differentiation of the human NK-cell lineage and further suggest a potential negative control on IFN-γ production in more mature human NK cells.

Highlights

Natural killer (NK) cells are the third largest group of lymphocytes in peripheral blood and an important component of the first line of immune defense
Following further addition of IL-2 from day 14, the differentiating cells are cultured for a total period of 35–42 days, by which time a regular culture comprises over 95% natural killer (NK) cells
To determine the repertoire of transcription factors differentially expressed during NK-cell development, we first performed a transcriptomic profiling study comparing samples from different time points up to day 35 with cultures at day 10

Summary

Introduction

Natural killer (NK) cells are the third largest group of lymphocytes in peripheral blood and an important component of the first line of immune defense. As components of the innate part of the immune system, they display immediate reactivity and do not require prior sensitization [1, 2]. This traditional characterization of NK cells has been expanded over the recent years as they have been described to be able to incorporate features previously thought to be restricted to the adaptive immune system, such as interaction with dendritic cells and immunological memory [3,4,5]. Whereas conventional NK cells resemble cytotoxic T lymphocytes in many aspects, ILCs 1–3 rather mirror T helperlike cells [7]

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Conclusion