The transcription factor HAND2 up-regulates transcription of the IL15 gene in human endometrial stromal cells.

Cyclic changes of the human endometrium, such as proliferation, secretion, and decidualization, occur during regular menstrual cycles. Heart- and neural crest derivatives-expressed transcript 2 (HAND2) is a key transcription factor in progestin-induced decidualization of human endometrial stromal cells (ESCs). It has been suggested that HAND2 regulates interleukin 15 (IL15), a key immune factor required for the activation and survival of uterine natural killer (uNK) cells. Activated uNK cells can promote spiral artery remodeling and secrete cytokines to induce immunotolerance. To date, no studies have evaluated the transcription factors that regulate IL15 expression in human ESCs. In the present study, we examined whether HAND2 controls IL15 transcriptional regulation in human ESCs. Quantitative RT-PCR and histological analyses revealed that HAND2 and IL15 levels increase considerably in the secretory phase of human endometrium tissues. Results from ChIP-quantitative PCR suggested that HAND2 binds to a putative HAND2 motif, which we identified in the upstream region of the human IL15 gene through in silico analysis. Using a luciferase reporter assay, we found that the upstream region of the human IL15 gene up-regulates reporter gene activities in response to estradiol and a progestin representative (medroxyprogesterone) in ESCs. The upstream region of the human IL15 gene also exhibited increasing responsiveness to transfection with a HAND2 expression vector. Of note, deletion and substitution variants of the putative HAND2 motif in the upstream region of IL15 did not respond to HAND2 transfection. These findings confirm that HAND2 directly up-regulates human IL15 transcription in ESCs.

Resveratrol protects mitochondrial quantity by activating SIRT1/PGC-1α expression during ovarian hypoxia.

PURPOSE: Resveratrol is a well-known potent activator of sirtuin-1 (SIRT1). We investigated the direct effects of hypoxia and resveratrol on SIRT1/ peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) pathways, vascular endothelial growth factor (VEGF), hypoxia-inducible factor (HIF)-1α, and mitochondrial quantity in a steroidogenic human ovarian granulosa-like tumor cell line (KGN) cells. METHODS: KGN cells were cultured with cobalt chloride (CoCl2; a hypoxia-mimicking agent) and/or resveratrol. The mRNA and protein levels, protein secretion, and intracellular localization were assessed by real-time PCR, Western blot analysis, ELISA, and immunofluorescence staining, respectively. Mitochondrial quantity was measured based on the mitochondrial DNA (mtDNA) copy number. RESULTS: CoCl2 simultaneously attenuated the levels of SIRT1 and mtDNA expression, and induced the levels of VEGF protein production. In contrast, resveratrol significantly increased the levels of SIRT1 and mtDNA copy number, but reduced VEGF production in normoxia. Resveratrol could recover CoCl2-suppressed SIRT1 and mtDNA expression and antagonize CoCl2-induced VEGF production. CoCl2 treatment resulted in a downregulation of PGC-1α expression, and this effect was recovered by resveratrol. Resveratrol significantly suppressed the production of the CoCl2-induced HIF-1α and VEGF proteins. CONCLUSION: These results suggest that resveratrol improves mitochondrial quantity by activating the SIRT1/PGC-1α pathway and inhibits VEGF induction through HIF-1α under hypoxic conditions.

Concentration of stromal cell-derived factor-1 (SDF-1/CXCL12) in the follicular fluid is associated with blastocyst development.

PURPOSE: To study the association between stromal cell-derived factor-1 (SDF-1/CXCL12) and vascular endothelial growth factor (VEGF) concentrations in individual human ovarian follicles and IVF outcomes. METHODS: Concentrations of SDF-1 and VEGF in 261 follicular fluid samples were measured with enzyme-linked immunosorbent assay. IVF outcome parameters were included in fertilization rate, cleavage rate, embryo morphology on day 3, and blastocyst morphology on day 5. RESULTS: The follicular concentration of SDF-1 and VEGF was not significantly associated with fertilization and cleavage outcome, and embryo morphology. The rates of full blastocysts and good-quality blastocysts were significantly higher in follicles with an SDF-1 concentration of 275-350 pg/mL than in the follicles with SDF-1 concentrations of <200 and ≥350 pg/mL (P < 0.05). The follicular concentration of VEGF was not associated with the blastocyst morphology. CONCLUSION: Our findings showed that follicular concentration of SDF-1, and not VEGF, may be a valuable biochemical marker of blastocyst development.

Thyroid Hormone Facilitates in vitro Decidualization of Human Endometrial Stromal Cells via Thyroid Hormone Receptors.

Endometrial stromal cells differentiate into decidual cells through the process of decidualization. This differentiation is critical for embryo implantation and the successful establishment of pregnancy. Recent epidemiological studies have suggested that thyroid hormone is important in the endometrium during implantation, and it is commonly believed that thyroid hormone is essential for proper development, differentiation, growth, and metabolism. This study aimed to investigate the impact of thyroid hormone on decidualization in human endometrial stromal cells (hESCs) and define its physiological roles in vitro by gene targeting. To identify the expression patterns of thyroid hormone, we performed gene expression profiling of hESCs during decidualization after treating them with the thyroid hormone levothyroxine (LT4). A major increase in decidual response was observed after combined treatment with ovarian steroid hormones and thyroid hormone. Moreover, LT4 treatment also affected the regulation of many transcription factors important for decidualization. We found that type 3 deiodinase, which is particularly important in fetal and placental tissues, was upregulated during decidualization in the presence of thyroid hormone. Further, it was observed that progesterone receptor, an ovarian steroid hormone receptor, was involved in thyroid hormone-induced decidualization. In the absence of thyroid hormone receptor (TR), due to the simultaneous silencing of TRα and TRß, thyroid hormone expression was unchanged during decidualization. In summary, we demonstrated that thyroid hormone is essential for decidualization in the endometrium. This is the first in vitro study to find impaired decidualization as a possible cause of infertility in subclinical hypothyroidism (SCH) patients.

Glucose transporter 1 is important for the glycolytic metabolism of human endometrial stromal cells in hypoxic environment.

AIM: The study aimed to elucidate the glycolytic metabolism of human endometrial stromal cells (hESCs) in hypoxic environment. MAIN METHODS: The hESCs were cultured in hypoxic environment, and their metabolic pathways were analyzed using metabolomics. We assessed glucose uptake using 2-deoxyglucose (2-DG) assay. The expression of glucose transporters (GLUTs) required for glucose uptake was determined using real-time quantitative polymerase chain reaction (qPCR) and western blotting. Furthermore, we knocked down GLUT1 and examined the uptake of 2-DG. KEY FINDINGS: Under hypoxia, glucose-6-phosphate, fructose-6-phosphate, and fructose-1,6-diphosphate were significantly elevated in hESCs (P < 0.05). This finding indicated enhancement in glycolysis. The volume of glucose uptake increased significantly under hypoxia (P < 0.05). Hypoxia simultaneously induced the expression of GLUT1 and GLUT3 mRNA (P < 0.05) and attenuated the expression of GLUT8 (P < 0.05). Glucose uptake was significantly inhibited upon knockdown of GLUT1 (P < 0.0001). SIGNIFICANCE: These results demonstrated a very important role of glucose transport under hypoxia. Also, hESCs utilize glycolysis to adapt to hypoxic conditions that could occur in menstrual and implantation period. These findings pave the way to study implantation failure and tumors originating from the endometrium.

Progestin-induced heart and neural crest derivatives-expressed transcript 2 inhibits angiopoietin 2 via fibroblast growth factor 9 in human endometrial stromal cells.

Heart and neural crest derivatives-expressed transcript 2 (HAND2) is a key transcription factor in progestin-induced decidualization of human endometrial stromal cells (ESCs). In the mouse, HAND2 plays an important role in uterine receptivity by suppressing several fibroblast growth factors (FGFs). However, the regulation of FGF family members by progestin-induced HAND2 and the role of FGF in vascular regeneration in the endometrium remains poorly understood. To investigate these molecular mechanisms, primary human ESCs were cultured with estradiol (E2), medroxyprogesterone acetate (MPA), progesterone receptor (PR) antagonist RU486, HAND2-specific small interfering RNA (siRNA), and recombinant FGF. The expression levels of FGF family members, HAND2, angiopoietin (ANGPT), and vascular endothelial growth factor (VEGF) were assessed by real-time PCR and ELISA. Out of six FGF genes known to be expressed in the human endometrium, only one, FGF9, was significantly downregulated in human ESCs after 3 days of progestin treatment. E2 + MPA attenuated the mRNA and protein levels of FGF9 during decidualization of ESCs, and this effect was blocked by RU486. Silencing of HAND2 significantly increased FGF9 expression in ESCs treated with E2 + MPA. Moreover, FGF9 activated FGF receptor in human ESCs, triggering ANGPT2 production, which resulted in enhancement of the ANGPT2/ANGPT1 protein ratio. Taken together, progestin-PR signaling and its target HAND2 play an essential role in FGF9 suppression in the human endometrium. In addition, progestin-induced HAND2 inhibits ANGPT2 production by suppressing FGF9 in ESCs. These results suggest that HAND2 may contribute to endometrial vascular maturation by regulating FGF9 during decidualization.

The steroid hormone dydrogesterone inhibits myometrial contraction independently of the progesterone/progesterone receptor pathway.

AIMS: In this study, we aimed to investigate the direct effects of steroid hormones on pregnant myometrial contraction. MAIN METHODS: The effect of steroids on oxytocin-induced contraction was examined in vitro using pregnant rat or human myometrium. Subsequently, we evaluated whether RU486, a potent progesterone antagonist, influenced the effects of progestin on myometrial contraction. Additionally, we evaluated the effects of progestin on high-concentration KCl-induced contraction caused by voltage-dependent calcium channels in order to investigate the mechanisms involved in this process. KEY FINDINGS: Of the natural steroids examined, 17ß-estradiol, progesterone, testosterone, cortisol, and aldosterone did not influence oxytocin-induced contraction at concentrations <10-6 M. Of the tested progestins, medroxyprogesterone acetate, norethisterone, chlormadinone acetate, levonorgesterol, 17α-hydroxyprogesterone capronate, and dienogest had no effect on contraction at <10-6 M. However, dydrogesterone showed rapid and direct inhibition of contraction at 10-6 M, and this inhibitory effect was dependent on dose and time. RU486 did not block the inhibitory effects of dydrogesterone on contraction. High-concentration KCl-induced contraction was also inhibited by dydrogesterone, and the inhibitory effects of dydrogesterone were observed at concentrations as low as 10-7 M. Additionally, oxytocin-induced contraction in pregnant human myometrium was inhibited by 10-6 M dydrogesterone. SIGNIFICANCE: These results suggested that the rapid and direct effects of dydrogesterone on myometrial contraction were caused by a nongenomic pathway and that the progesterone receptor was not required for dydrogesterone action. Additionally, the mechanism of dydrogesterone action may involve voltage-dependent calcium channels.