The uterus in early pregnancy is a non-lymphoid organ that is enriched in natural killer （NK） cells. Studies to address the role of these abundant human NK cells at the maternal/fetal interface have focused on their...The uterus in early pregnancy is a non-lymphoid organ that is enriched in natural killer （NK） cells. Studies to address the role of these abundant human NK cells at the maternal/fetal interface have focused on their response to the major histocompatibility complex （MHC） molecules on fetal trophoblast cells that they contact. The interaction of maternal NK cell receptors belonging to the killer cell immunoglobulin-like receptor （KIR） family with trophoblast MHC class I molecules in pregnancy can regulate NK cell activation for secretion of pro-angiogenic factors that promote placental development. This review will cover the role of KIR at the maternal/fetal interface and focus on KIR2DL4, a KIR family member that is uniquely poised to play a role in pregnancy due to the restricted expression of its ligand, human leukocyte antigen （HLA）-G, by fetal trophoblast cells early in pregnancy. The pathways by which KIR2DL4-HLA-G interactions induce the cellular senescence of NK cells and the role of the resulting senescence-associated secretory phenotype （SASP） in vascular remodeling will be discussed in the context of reproduction.展开更多
Human leukocyte antigen-G (HLA-G) has long been speculated as a beneficial factor for a successful pregnancy for its restricted expression on fetal-maternal extravillous cytotrophoblasts and its capability of modulati...Human leukocyte antigen-G (HLA-G) has long been speculated as a beneficial factor for a successful pregnancy for its restricted expression on fetal-maternal extravillous cytotrophoblasts and its capability of modulating uterine natural killer cell (uNK) function such as cytotoxicity and cytokine production through NK cell receptors. HLA class I α1 domain is an important killer cell Ig-like receptor (KIR) recognition site and the Met76 and Gln79 are unique to HLA-G in this region. NK cell receptor KIR2DL4 is a specific receptor for HLA-G, yet the recognition site on HLA-G remains unknown. In this study, retroviral transduction was applied to express the wild type HLA-G (HLA-wtG), mutant HLA-G (HLA-mG) on the chronic myelogenous leukemia cell line K562 cells and KIR2DL4 molecule on NK-92 cells, respectively. KIR2DL4-IgG Fc fusion protein was generated to determine the binding specificity between KIR2DL4 and HLA-G. Our results showed that residue Met76, Gln79 mutated to Ala76,79 in the α1 domain of HLA-G protein could affect the binding affinity between KIR2DL4 and HLA-G, meanwhile, the KIR2DL4 transfected NK-92 cells (NK-92- 2DL4) showed a considerably different cytolysis ability against the HLA-wtG and HLA-mG transfected K562 targets. Taken together, our data indicated that residue Met76 and Gln79 in HLA-G α1 domain plays a critical role in the recogni- tion of KIR2DL4, which could be an explanation for the isoforms of HLA-G, all containing the α1 domain, with the potential to regulate NK functions.展开更多
文摘The uterus in early pregnancy is a non-lymphoid organ that is enriched in natural killer （NK） cells. Studies to address the role of these abundant human NK cells at the maternal/fetal interface have focused on their response to the major histocompatibility complex （MHC） molecules on fetal trophoblast cells that they contact. The interaction of maternal NK cell receptors belonging to the killer cell immunoglobulin-like receptor （KIR） family with trophoblast MHC class I molecules in pregnancy can regulate NK cell activation for secretion of pro-angiogenic factors that promote placental development. This review will cover the role of KIR at the maternal/fetal interface and focus on KIR2DL4, a KIR family member that is uniquely poised to play a role in pregnancy due to the restricted expression of its ligand, human leukocyte antigen （HLA）-G, by fetal trophoblast cells early in pregnancy. The pathways by which KIR2DL4-HLA-G interactions induce the cellular senescence of NK cells and the role of the resulting senescence-associated secretory phenotype （SASP） in vascular remodeling will be discussed in the context of reproduction.
文摘Human leukocyte antigen-G (HLA-G) has long been speculated as a beneficial factor for a successful pregnancy for its restricted expression on fetal-maternal extravillous cytotrophoblasts and its capability of modulating uterine natural killer cell (uNK) function such as cytotoxicity and cytokine production through NK cell receptors. HLA class I α1 domain is an important killer cell Ig-like receptor (KIR) recognition site and the Met76 and Gln79 are unique to HLA-G in this region. NK cell receptor KIR2DL4 is a specific receptor for HLA-G, yet the recognition site on HLA-G remains unknown. In this study, retroviral transduction was applied to express the wild type HLA-G (HLA-wtG), mutant HLA-G (HLA-mG) on the chronic myelogenous leukemia cell line K562 cells and KIR2DL4 molecule on NK-92 cells, respectively. KIR2DL4-IgG Fc fusion protein was generated to determine the binding specificity between KIR2DL4 and HLA-G. Our results showed that residue Met76, Gln79 mutated to Ala76,79 in the α1 domain of HLA-G protein could affect the binding affinity between KIR2DL4 and HLA-G, meanwhile, the KIR2DL4 transfected NK-92 cells (NK-92- 2DL4) showed a considerably different cytolysis ability against the HLA-wtG and HLA-mG transfected K562 targets. Taken together, our data indicated that residue Met76 and Gln79 in HLA-G α1 domain plays a critical role in the recogni- tion of KIR2DL4, which could be an explanation for the isoforms of HLA-G, all containing the α1 domain, with the potential to regulate NK functions.
