Human-induced CD49a+ NK cells promote fetal growth

CD49a+ natural killer (NK) cells are critical in promoting fetal development and maintaining immune tolerance at the maternal-fetal interface in early pregnancy. However, their tissue residency in human tissue hinder thorough studies and clinical application. How to induce functional human CD49a+ NK cells that could benefit pregnancy outcomes is still unknown. Here, we have established three no feeder cell induction systems to induce human CD49a+ NK cells from umbilical cord blood hematopoietic stem cells (HSCs), bone marrow HSCs or peripheral blood NK cells, respectively. These induced NK cells (iNKs) from three cell induction systems show high expression of CD49a, CD9, CD39, CD151, low expression of CD16, and no obvious cytotoxic capability, phenotypically and functionally similar with decidual NK cells. Furthermore, these iNKs also have high expression of growth-promoting factors and proangiogenic factors. Importantly, these iNKs have shown their capabilities to promote fetal growth and improve uterine artery blood flow in a murine pregnancy model in vivo. This research reveals properties of human-induced CD49a+ NK cells in promoting fetal growth from three cell induction systems, which may improve the feasibility of applying these iNKs to the patients having adverse pregnancy outcomes. Overall design: The mRNA profiles of decidual NK cells, peripheral blood NK cells, induced CD49a+ NK cells from umbilical cord blood hematopoietic stem cells (HSCs), bone marrow HSCs or peripheral blood NK cells. Samples were all from healthy people.