Multi-tissue Single-Cell Analysis Deconstructs the Complexities of Mouse NK-ILC1 Programs

Natural killer (NK) cells and type 1 innate lymphoid cells (ILC1s) are a heterogenous group of T-bet+ innate cells that produce IFN-γ and are broadly defined as lineage–NK1.1+NKp46+ cells in mice. ILC1s definition primarily stems from studies on liver-resident and small intestinal populations. However, ILC1s in many anatomical sites, including visceral adipose tissue, salivary glands, and uterus, exhibit non-uniform programs that do not adequately overlap with those of liver or gut ILC1s or NK cells. Here, we performed single-cell RNA sequencing on murine NK1.1+NKp46+ cells from blood, spleen, lymph nodes, liver, salivary gland, uterus, visceral adipose tissue, small intestines, and several solid tumors. By including cells from an array of niches we defined tissue-specific ILC1 subsets. Moreover, we found a significant heterogeneity of circulating NK cells, due to a spectrum of proliferating, effector and migration programs, which was reduced in tumor-bearing mice, demonstrating repertoire reshaping in response to diseased conditions. NK/ILC1 cells (NK1.1+,NCR1+