Natural killer (NK) cells are the predominant innate lymphocyte subsets that mediate anti-tumor and anti-viral responses, and therefore possess promising clinical utilization. NK cells do not express polymorphic clonotypic receptors and utilize inhibitory receptors (killer immunoglobulin-like receptor and Ly49) to develop, mature, and recognize “self” from “non-self.” The essential roles of common gamma cytokines such as interleukin (IL)-2, IL-7, and IL-15 in the commitment and development of NK cells are well established. However, the critical functions of pro-inflammatory cytokines IL-12, IL-18, IL-27, and IL-35 in the transcriptional-priming of NK cells are only starting to emerge. Recent studies have highlighted multiple shared characteristics between NK cells the adaptive immune lymphocytes. NK cells utilize unique signaling pathways that offer exclusive ways to genetically manipulate to improve their effector functions. Here, we summarize the recent advances made in the understanding of how NK cells develop, mature, and their potential translational use in the clinic.

Natural killer (NK) cells are critical to both innate and adaptive immunity. However, the development and heterogeneity of human NK cells are yet to be fully defined. Using single-cell RNA-sequencing technology, here we identify distinct NK populations in human bone marrow and blood, including one population expressing higher levels of immediate early genes indicative of a homeostatic activation. Functionally matured NK cells with high expression of CX3CR1 , HAVCR2 (TIM-3), and ZEB2 represents terminally differentiated status with the unique transcriptional profile. Transcriptomic and pseudotime analyses identify a transitional population between CD56 bright and CD56 dim NK cells. Finally, a donor with GATA2 T354M mutation exhibits reduced percentage of CD56 bright NK cells with altered transcriptome and elevated cell death. These data expand our understanding of the heterogeneity and development of human NK cells.

RNA is rarely used as a therapeutic target due to its flexible structure and instability. CRISPR‐Cas13a is a powerful tool for RNA knockdown, and the potential application of CRISPR‐Cas13a in cancer cells should be further studied. In this study, overexpression of LwCas13a by lentivirus in glioma cells reveals that crRNA‐EGFP induces a “collateral effect” after knocking down the target gene in EGFP‐expressing cells. EGFRvIII is a unique EGFR mutant subtype in glioma, and the CRISPR‐Cas13a system induces death in EGFRvIII‐overexpressing glioma cells. Bulk and single‐cell RNA sequencing analysis in U87‐Cas13a‐EGFRvIII cells confirm the collateral effect of the CRISPR‐Cas13a system. Furthermore, CRISPR‐Cas13a inhibits the formation of glioma intracranial tumors in mice. The results demonstrate the collateral effect of the CRISPR‐Cas13a system in cancer cells and the powerful tumor‐eliminating potential of this system.