Granulysin-high decidual NK cells in macaques and humans share signatures of immune defense and regulation

Decidual NK cells (dNK) are key immune effector cells at the maternal-fetal interface. dNK utilize the anti-microbial peptide granulysin (GNLY) to kill pathogens, without killing trophoblast cells. Since rodents lack the GNLY gene, the in vivo biology of GNLY expression by dNK and their control of microbes is not well-understood. Here we defined dNK GNLY expression in placental membranes of Rhesus macaques and humans. GNLY-high dNK of both species shared conserved transcriptional and protein signatures of anti-microbial defense and immunoregulation. In addition, both human and rhesus GNLY-high dNK responded to inflammation and infection by increasing their cytotoxic, cytokine and inflammatory signatures. Thus high GNLY expression defines a unique dNK type with active roles in innate immune defense in humans and Rhesus macaques. Defining the regulatory networks of GNLY expression by dNK and their mechanism of infection control will open up therapeutic opportunities to enhance immunity and reduce infection-related pregnancy complications Overall design: CAMD (chorio-amnion-decidual membranes) from pre-term deliveries (two without inflammation denoted "CTR", two with acute chorioamnionitis denoted "ACA") were formalin-fixed paraffin-embedded and later used for scRNA-seq transcriptomic analysis, in comparison with preterm Rhesus macaque CAMD that had been intra-amnionically injected with saline or LPS (the Rhesus scRNA-seq data are available under a separate GEO entry). The sample numbers 1, 2, 4, 5 below correspond to the sample numbers in Table 1 of the manuscript. This study was supported by: . Cincinnati Children's Research Foundation (CCRF) Tilburgs lab startup funds (Tamara Tilburgs) . CCRF Research Innovation Pilot (RIP) Award (Tamara Tilburgs) . Fixed RNA Profiling Grant Program - 10X Genomics (Pietro Presicce) . March of Dimes Prematurity Research Center Ohio Collaborative (Tamara Tilburgs) . Burroughs Wellcome Fund Next Gen Pregnancy Award #NGP10115 (Tamara Tilburgs) . CCHMC Vaccinology Training Program NIH T32 AI165396 (Nina Pransaphanich) . K12-HD000850 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (Nina Prasanphanich)