Differentiation of c-Kit + CD24 + natural killer cells into myeloid cells in a GATA-2-dependent manner.

Myeloid progenitor cells have generally been considered the predominant source of myeloid cells under steady-state conditions. Here we show that NK cells contributed to a myeloid cell lineage pool in naive and tumor-bearing mice. Using fate tracing of NKp46(+) cells, we found that myeloid cells could be derived from NK cells. Notably, among mature CD11b(+)CD27(+) NK cells, c-Kit(+)CD24(+) NK cells were capable of differentiating into a range of myeloid lineages in vitro and produced neutrophils and monocytes in vivo. The differentiation was completely inhibited by NK-stimulating cytokines. In addition to the potential for differentiation into myeloid cells, c-Kit(+)CD24(+) NK cells retained NK cell phenotypes and effector functions. Mechanistically, GATA-2 was necessary for the differentiation of c-Kit(+)CD24(+) NK cells. Therefore, we discovered that GATA-2-dependent differentiation of c-Kit(+)CD24(+) NK cells contributes to myeloid cell development and identified a novel pathway for myeloid lineage commitment under physiological conditions.