[18, 50, 51, 59-61] Some of these soluble factors play a major role in the recruitment and attraction of fetal trophoblasts (i.e. CXCL10/IP-10, CXCL8/IL-8, CXCL12/SDF-1 and CCL2/MCP-1).[18, 50, 51, 59, 61] In contrast, invasive fetal trophoblasts can also help in the accumulation of dNK cells at the maternal decidua through the secretion of chemokines, such as SDF-1 and MIP-1α.[43] Other factors, such as vascular endothelial

growth factor (VEGF) C produced by dNK cells, can participate in immune tolerance by inducing TAP-1 expression, MHC class I AZD1208 research buy molecule assembly and cell surface expression on trophoblasts.[60] The fact that this secretion profile can be modulated by the ligation of a specific NK cell receptor suggests that the cross-talk between dNK cells and the invasive trophoblast

expressing NKR ligands can regulate the secretion abilities of dNK cells.[62] Evidence for the contribution of uterine NK cells in early phases of decidual angiogenesis was first provided by B.A. Croy and her colleagues using several strains of immunodeficient mice.[63-65] The picture is less clear in humans and the role of dNK cells in vascular remodelling is based on observations showing the presence of dNK cells in the vicinity of changing vessels. However, even if the role of human dNK cells in vasculature remodelling is not yet fully elucidated, these cells produce various pro-angiogenic and growth factors such as placental growth factor, VEGF A, and VEGF C, which can favour angiogenesis.[50, 60, 66] Vascular remodelling occurs in Ipatasertib cell line two steps that result in loss of the musculo-elastic structure and formation of breaks in the endothelial layer, which is then followed by the attraction of EVTs that become endovascular

trophoblasts and replace the endothelium lining deep into the endometrium and partly into the myometrium.[67, 68] Both steps have been linked to the presence of dNK cells at the vicinity of the changing vessels. Changes of uterine arteries are crucial for the success of pregnancy because they ensure minimal vessel Phosphoglycerate kinase resistance and high blood flow of nutrients as well as oxygen to the conceptus.[14, 19] Immunohistochemical studies have demonstrated that the initial step of vasculature remodelling that takes place before the invasion of fetal trophoblasts is associated with significant accumulation of dNK cells and decidual macrophages within the vascular wall,[69, 70] and more recently R. Fraser and his colleagues confirmed the contribution of dNK cells to early phases of vascular remodelling in human pregnancy.[71] Defaults in trophoblast invasion and/or vascular remodelling are hallmarks of pathological pregnancy, such as pre-eclampsia. Genetic studies suggested that special combinations of fetal HLA-C haplotypes and maternal dNK cell inhibitory KIRs increased the likelihood of pre-eclampsia.