Many differences exist between human immature and mature natural killer (NK) cells, but their respective molecular signatures and transcriptional regulators are relatively unknown. To gain new insights into the diversity and developmental regulation of human NK cells, we used data from high-resolution microarrays with independent verification to describe a comprehensive comparative analysis between immature decidual NK (idNK) cells with a Eur. J. Immunol. 2014. 44: 2771-2784 activity [6,7]. Our previous work showed that most dNK cells belong to the CD27 − CD11b − subset, which has an immature phenotype, displays developmental potential in response to IL-15, and increases cytotoxic potential in response to insulin-like growth factor 1 (IGF-1) [8,9]. Several exogenous cytokines are involved in NK-cell development and function, including IL-2, IL-15, and IL-21, and novel endogenous cytokines have more recently been found, including bone morphogenetic protein 4 (BMP4) and IGF-1 [9][10][11]. Although many transcription factors (TFs) have been identified to affect NK-cell differentiation or function in mice, including ID2, NFIL3 (E4BP4), EOMES, ETS-1, and T-bet, little is known about human NK-cell transcriptional regulators [12][13][14]. Since the molecular signature of NK cells has been well-described in mice [15], we sought to compare the results from mouse models to humans to see if developmental mechanisms are conserved.Using human whole-genome microarray data sets with subsequent verification, we provide novel molecular descriptions for human immature and mature NK cells; most importantly, our findings offer new insights into the transcriptional regulators that govern NK-cell development and function. Our study thus provides a valuable resource for further investigations into NK-cell biology.
Results idNK cells exhibit immature characteristics compared with mpNK cellsNK cells in the peripheral blood account for a small fraction of total lymphocytes (ß10%) and are composed of two different subsets: the predominant CD56 dim CD16 + mature subset (ß95%) and the much smaller CD56 bright CD16 − immature subset (ß5%).In contrast, NK cells are the dominant lymphocyte in the decidua during normal pregnancy, comprising up to ß70% of the total lymphocytes and approximately 90% of dNK cells were of the CD56 bright CD16 − immature phenotype [6,16] (Fig. 1A and B, and Supporting Information Fig. 1A and C). T-bet regulates the terminal maturation and function of murine NK cells during the final stage of development [17]. ID2 is expressed in NK-cell progenitors and regulates their early developmental processes [13,18]. To further confirm that dNK cells are more immature than pNK cells, we analyzed T-bet and ID2 expression. Interestingly, we found that dNK cells were mostly T-bet − , while >90% of the pNK cells were T-bet + ( Fig. 1A and B). Additionally, western blot analysis showed that ID2 was exclusively expressed by dNK cells (Fig. 1C). Furthermore, we detected many known cell-surface markers related to NK-cell maturation. C...