Derivation of functional early gestation decidual natural killer cell subtypes from induced pluripotent stem cells

Abnormal decidual natural killer cell (dNK) function is linked to pregnancy complications occurring in both early and late stages of gestation, including recurrent pregnancy loss, preeclampsia, and preterm birth. Exploration of dNK heterogeneity as it relates to function is an active area of research; however, most of this work has focused on early gestation. We applied flow cytometric and transcriptomic single cell definitions of dNK subtypes to dNK at the chorioamniotic membranes (CAM) and basal plate (BP) of the placenta at term. We found decreased low-effector-function dNK1 and increased high-effector-function dNK3 abundance at term. In comparison to BP-dNK, CAM-dNK had greater abundance of moderate-effector-function dNK2 and lower expression of inhibitory CD9. We applied this knowledge to establish a protocol for differentiation of induced pluripotent stem cells (iPSC) into CD45 ⁺ CD56 ^bright CD16 ^- , functional dNK-like, applying TGFβ to enrich for dNK2 – the most abundant dNK subtype at first trimester– while inducing expression of dNK markers, CD9 and CD103. We analyzed the secretomes of first trimester dNK, term BP-dNK and CAM-dNK, and peripheral blood NK cells to identify proteomic profiles for each. Finally, we analyzed the secretome of TGFβ-treated iPSC-dNK and found an enrichment in first trimester dNK-specific proteins. We identify changes in dNK function across gestation and placental region and suggests that these changes can be explained by shifts in dNK subtypes, which we specifically and reproducibly derive from iPSC, providing a new model for these cells and laying the foundation for cell-based therapies of reproductive diseases.