scholarly journals Involvement of uterine natural killer cells in the natural selection of human embryos at implantation

2020 ◽  
Author(s):  
Chow-Seng Kong ◽  
Alexandra Almansa Ordoñez ◽  
Sarah Turner ◽  
Tina Tremaine ◽  
Joanne Muter ◽  
...  

AbstractDecidualizing endometrial stromal cells (EnSC) critically determine the maternal response to an implanting conceptus, triggering either menstruation-like disposal of low-fitness embryos or creating an environment that promotes further development. However, the mechanism that couples maternal recognition of low-quality embryos to tissue breakdown remains poorly understood. Recently, we demonstrated that successful transition of the cycling endometrium to a pregnancy state requires selective elimination of pro-inflammatory senescent decidual cells by activated uterine natural killer (uNK) cells. Here we report that uNK cells express CD44, the canonical hyaluronan (HA) receptor, and demonstrate that high-molecular weight HA (HMWHA) inhibits uNK cell-mediated killing of senescent decidual cells. By contrast, low-molecular weight HA (LMWHA) did not attenuate uNK cell activity in co-culture experiments. Killing of senescent decidual cells by uNK cells was also inhibited upon exposure to medium conditioned by IVF embryos that failed to implant, but not successful embryos. Embryo-mediated inhibition of uNK cell activity was reversed by recombinant hyaluronidase 2 (HYAL2), which hydrolyses HMWHA. We further report a correlation between the levels of HYAL2 secretion by human blastocysts, morphological scores, and implantation potential. Taken together, the data suggest a pivotal role for uNK cells in embryo biosensing and endometrial fate decisions at implantation.

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Paul J Brighton ◽  
Yojiro Maruyama ◽  
Katherine Fishwick ◽  
Pavle Vrljicak ◽  
Shreeya Tewary ◽  
...  

In cycling human endometrium, menstruation is followed by rapid estrogen-dependent growth. Upon ovulation, progesterone and rising cellular cAMP levels activate the transcription factor Forkhead box O1 (FOXO1) in endometrial stromal cells (EnSCs), leading to cell cycle exit and differentiation into decidual cells that control embryo implantation. Here we show that FOXO1 also causes acute senescence of a subpopulation of decidualizing EnSCs in an IL-8 dependent manner. Selective depletion or enrichment of this subpopulation revealed that decidual senescence drives the transient inflammatory response associated with endometrial receptivity. Further, senescent cells prevent differentiation of endometrial mesenchymal stem cells in decidualizing cultures. As the cycle progresses, IL-15 activated uterine natural killer (uNK) cells selectively target and clear senescent decidual cells through granule exocytosis. Our findings reveal that acute decidual senescence governs endometrial rejuvenation and remodeling at embryo implantation, and suggest a critical role for uNK cells in maintaining homeostasis in cycling endometrium.


2017 ◽  
Author(s):  
Paul J Brighton ◽  
Yojiro Maruyama ◽  
Katherine Fishwick ◽  
Pavle Vrljicak ◽  
Shreeya Tewary ◽  
...  

SummaryIn cycling human endometrium, menstruation is followed by rapid estrogen-dependent growth. Upon ovulation, progesterone and rising cellular cAMP levels activate the transcription factor Forkhead box O1 (FOXO1) in endometrial stromal cells (EnSCs), leading to cell cycle exit and differentiation into decidual cells that control embryo implantation. Here we show that FOXO1 also causes acute senescence of a subpopulation of decidualizing EnSCs in an IL-8 dependent manner. Selective depletion or enrichment of this subpopulation revealed that decidual senescence drives the transient inflammatory response associated with endometrial receptivity. Further, senescent cells prevent differentiation of endometrial mesenchymal stem cells in decidualizing cultures. As the cycle progresses, IL-15 activated uterine natural killer (uNK) cells selectively target and clear senescent decidual cells through granule exocytosis. Our findings reveal that acute decidual senescence governs endometrial rejuvenation and remodeling at embryo implantation, and suggest a critical role for uNK cells in maintaining homeostasis in cycling endometrium.


Endocrinology ◽  
2009 ◽  
Vol 150 (6) ◽  
pp. 2882-2888 ◽  
Author(s):  
Nicole Kane ◽  
Rodney Kelly ◽  
Philippa T. K. Saunders ◽  
Hilary O. D. Critchley

The endometrial lining of the human uterus contains a population of phenotypically distinct (CD56bright, CD16dim), tissue-specific, natural killer [uterine natural killer (uNK)] cells that play a key role in the establishment of a successful pregnancy. An increase in the number of endometrial uNK cells occurs when the conceptus implants, and there is a further increase during the early stages of placentation. Here, we describe studies that have identified human chorionic gonadotrophin (hCG), a glycoprotein synthesized by the preimplantation conceptus, as a novel regulator of uNK cell proliferation. The impact of hCG on uNK cells was mediated via the mannose receptor (CD206) rather than by the classical hCG/LH receptor that was not expressed. The mannose receptor and hCG were colocalized on the surface of uNK cells, and proliferation did not occur if cells were incubated with deglycosylated hCG or intact hCG in the presence of excess d-Mannose. These novel observations provide new insight into the endocrine-immune dialogue that exists between the conceptus and immune cells within the receptive endometrium, and have implications for the role of uNK cell-trophoblast interactions and pregnancy outcome.


2015 ◽  
pp. 427-432 ◽  
Author(s):  
B. ZAVAN ◽  
A. M. DO AMARANTE-PAFFARO ◽  
V. A. PAFFARO

One of the most abundant immunologic cell types in early decidua is the uterine natural killer (UNK) cell that despite the presence of cytoplasmic granules rich in perforin and granzymes does not degranulate in normal pregnancy. UNK cells are important producers of angiogenic factors that permit normal dilation of uterine arteries to provide increased blood flow for the growing feto-placental unit. Gram-negative bacteria lipopolysaccharide (LPS) administration can trigger an imbalance of pro-inflammatory and anti-inflammatory cytokines impairing the normal immune cells activity as well as uterine homeostasis. The present study aimed to evaluate by immunohistochemistry the reactivity of perforin and α-actin on UNK cell from LPS-treated pregnant mice. For the first time, we demonstrate that LPS injection in pregnant mice causes α-actin down regulation, concomitantly with perforin loss in UNK cells. This suggests that LPS alters UNK cell migration and activates cytotoxic granule release.


2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Xin Gong ◽  
Zhenzhen Chen ◽  
Yanxia Liu ◽  
Qiudan Lu ◽  
Zhe Jin

The endometrium contains a population of immune cells that undergo changes during implantation and pregnancy. The majority of these cells are uterine natural killer (uNK) cells; however, it is unclear how these cells interact with endometrial epithelial cells. Therefore, we investigated the paracrine effects of the uNK cell-secretion medium on the gene expression profile of endometrial epithelial cellsin vitrothrough microarray analysis. Our results, which were verified by qRT-PCR and western blot, revealed that soluble factors from uNK cells alter the gene expression profiles of epithelial cells. The upregulated genes included interleukin-15 (IL-15) and interleukin-15 receptor alpha (IL-15RA), which result in a loop that stimulates uNK cell proliferation. In addition, vascular endothelial growth factor C (VEGF-C) and chemokine (C-X-C motif) ligand 10 (CXCL-10) were also determined to be upregulated in epithelial cells, which suggests that uNK cells work synergistically with epithelial cells to support implantation and pregnancy. In addition, oriental herbal medicines have been used to treat infertility since ancient times; however, we failed to find that Zi Dan Yin can regulate these endometrial paracrine effects.


2005 ◽  
Vol 17 (9) ◽  
pp. 120
Author(s):  
M. Hickey ◽  
J. M. Crewe ◽  
D. Doherty ◽  
I. S. Fraser ◽  
L. A. Salamonsen

Menopausal hormone therapy (HT) causes irregular bleeding in up to 60% of user. This is extremely unpopular with patients, and commonly leads to invasive and expensive investigations to rule out underlying pelvic pathology. In most cases no cause is found. The aim of this study was to further elucidate the mechanisms of vascular fragility. Uterine NK cells are known to increase vascular fragility during the normal menstrual cycle. We hypothesise that HT is associated with an increase in uterine natural killer (uNK) cells. Eighty six endometrial biopsies were obtained from 59 postmenopausal users of continuous combined HT. Uterine NK cells were identified using immunohistochemistry as being CD56+. Image analysis was used to identify absolute number of CD56+ cells and their distribution within the stroma. Endometrial histology was classified using Noyes criteria. A statistically significant increase in endometrial uNK cell density was observed in HT users compared to postmenopausal women not using HT (P < 0.001). uNK cell populations were more marked in biopsies taken during a bleeding episode compared to those HT users with amenorrhoea (P = 031). uNK cells are a major regulator of endometrial vascular integrity and are known to be disrupted in irregular bleeding with progestin only contraceptives. This is the first study to report the presence of uNK cells in postmenopausal endometrium and the first to report a significant association between bleeding patterns and uNK cell density. We postulate that HT induces an increase in endometrial uNK cell populations and that their presence stimulates endometrial vascular fragility leading to bleeding.


2020 ◽  
Vol 4 (s1) ◽  
pp. 102-102
Author(s):  
Jessica Kanter ◽  
Sneha Mani ◽  
Scott Gordon ◽  
Monica Mainigi

OBJECTIVES/GOALS: Human placentation requires complex coordination between maternal and fetal cell types but remains incompletely understood. We hypothesize that uterine natural killer (uNK) cells, an immune cell type that increases in abundance during the implantation window, is essential for appropriate implantation and placentation. METHODS/STUDY POPULATION: We plan to examine stromal cell (SC) decidualization, spiral artery remodeling, and EVT invasion, processes vital for early pregnancy establishment, in the presence or absence of secretory phase uNK cells. Fetal extravillous trophoblasts (EVTs) will be isolated from first trimester pregnancy tissue; maternal SCs, endothelial cells (ECs) and uNK cells will be obtained from secretory phase uterine tissue. SCs will be placed in monoculture and coculture with uNK cells and prolactin will be measured to evaluate decidualization. To study EVT invasion, we will utilize our novel “implantation-on-a-chip” device to determine how addition of uNK cells affects EVT migration through a collagen-matrigel matrix. In this system, we will also examine spiral artery remodeling with or without uNK cells via TUNEL staining. RESULTS/ANTICIPATED RESULTS: We anticipate that uNK cell addition to SCs will lead to a significant increase in SC prolactin levels, suggesting a role of uNK cells in endometrial decidualization. In vitro, we expect the addition of uNK cells will increase EC apoptosis and promote EVT invasion. DISCUSSION/SIGNIFICANCE OF IMPACT: Although decidual NK cells are known to participate in placentation, the role of pre-pregnancy uNK cells is unknown. uNK cell involvement in processes important for the earliest stages of pregnancy would provide a potential marker for abnormal placentation and offer avenues for intervention to decrease placentation associated perinatal morbidity.


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