Diesel exhaust exposure alters the expression of networks implicated in neurodegeneration in zebrafish brains.

Neurodegenerative diseases are a major cause of disability in the world, but their etiologies largely remain elusive. Genetic factors can only account for a minority of risk for most of these disorders, suggesting environmental factors play a significant role in the development of these diseases. Prolonged exposure to air pollution has recently been identified to increase the risk of Alzheimer's and Parkinson's diseases, but the molecular mechanisms by which it acts are not well understood. Zebrafish embryos exposed to diesel exhaust particle extract (DEPe) lead to dysfunctional autophagy and neuronal loss. Here, we exposed zebrafish embryos to DEPe and performed high throughput proteomic and transcriptomic expression analyses from their brains to identify pathogenic pathways induced by air pollution. DEPe treatment altered several biological processes and signaling pathways relevant to neurodegenerative processes, including xenobiotic metabolism, phagosome maturation, and amyloid processing. The biggest induction of gene expression in brains was in Cyp1A (over 30-fold). The relevance of this expression change was confirmed by blocking induction using CRISPR/Cas9, which resulted in a dramatic increase in sensitivity to DEPe toxicity, confirming that Cyp1A induction was a compensatory protective mechanism. These studies identified disrupted molecular pathways that may contribute to the pathogenesis of neurodegenerative disorders. Ultimately, determining the molecular basis of how air pollution increases the risk of neurodegeneration will help in the development of disease-modifying therapies.

Significance of placental CD200 expression in patients with preeclampsia: Comparison between early­ and late­onset patients.

Preeclampsia, characterized by high blood pressure and proteinuria during pregnancy, causes serious complications in both the mother and the fetus. Although there have been several studies on the causes of preeclampsia, the detailed mechanism of this disease remains unclear. Moreover, a few reports have focused on the causes of preeclampsia in number of weeks at onset. The present study aimed to elucidate the differences between early­ and late­onset preeclampsia. This study enrolled patients with preeclampsia from January 2014 to December 2020. They were classified into early­ (<34 weeks) and late­onset (≥34 weeks) preeclampsia groups. The expression profiles of 770 immune­related genes were studied in the placental tissue from five patients each in the early­ and late­onset groups. The expression of CD200 in the trophoblasts of the placenta of 26 and 27 patients in early­ and late­onset groups, respectively, was also analyzed using immunostaining. Analysis of extracted RNA indicated that CD200 was significantly upregulated in the early­onset group compared with late­onset group and normal control. Immunostaining for CD200 demonstrated a significantly increased expression in the early­onset group compared with the late­onset group. The present study demonstrated that upregulation of CD200, which belongs to the immunoglobulin superfamily and is recognized as a molecule that acts in immune tolerance via inhibition of classical macrophage activation, may be associated with early­onset preeclampsia, although it remains unknown whether upregulation of CD200 expression is a cause or effect of the development of early­onset preeclampsia. Early­onset preeclampsia might have a different mechanism from that of late­onset; thus, further studies are needed to clarify the mechanism of these conditions for adequate treatment.

The Regulators of Human Endometrial Stromal Cell Decidualization.

Several factors are important for implantation and subsequent placentation in the endometrium, including immunity, angiogenesis, extracellular matrix, glucose metabolism, reactive oxidative stress, and hormones. The involvement or abnormality of these factors can impair canonical decidualization. Unusual decidualization can lead to perinatal complications, such as disruption of trophoblast invasion. Drastic changes in the morphology and function of human endometrial stromal cells (hESCs) are important for decidualization of the human endometrium; hESCs are used to induce optimal morphological and functional decidualization in vitro because they contain estrogen and progesterone receptors. In this review, we will focus on the studies that have been conducted on hESC decidualization, including the results from our laboratory.

NDRG1 is expressed in human granulosa cells: An implicative role of NDRG1 in the ovary.

Purpose: N-myc downstream-regulated gene 1 (NDRG1) is expressed in various human tissues and plays a role in regulating cellular proliferation, angiogenesis, and hypoxia sensing. However, the role of NDRG1 in the ovary remains poorly understood. Therefore, we investigated NDRG1 expression and the role of NDRG1 in the human ovary. Methods: Follicular fluid (FF) and luteinized granulosa cells were collected from follicles during oocyte retrieval. KGN cells were cultured with cobalt chloride (CoCl2, a hypoxia-mimicking agent) and/or echinomycin. mRNA, protein levels and secretion, and localization were assessed by real-time PCR, Western blotting, ELISA, and immunohistochemical analysis, respectively. KGN cells were also transfected with NDRG1 siRNA for 72 h. Results: NDRG1 protein was expressed in luteinized granulosa cells. NDRG1 concentration was positively correlated with vascular endothelial growth factor (VEGF) and progesterone concentrations in FF. CoCl2-induced hypoxic stress significantly increased NDRG1 and VEGF mRNA and protein and hypoxia-inducible factor-1α expression compared with those in the controls. The CoCl2-induced overexpression of NDRG1 and VEGF was suppressed by echinomycin. Transfection with NDRG1 siRNA significantly suppressed the release of progesterone in the culture medium. Conclusions: These results indicate that ovarian NDRG1 may play important roles in follicular development, especially in the early luteinization of pre-ovulatory follicles.

Air Pollution and the Risk of Parkinson's Disease: A Review.

Parkinson's disease, as well as other neurodegenerative disorders, are primarily characterized by pathological accumulation of proteins, inflammation, and neuron loss. Although there are some known genetic risk factors, most cases cannot be explained by genetics alone. Therefore, it is important to determine the environmental factors that confer risk and the mechanisms by which they act. Recent epidemiological studies have found that exposure to air pollution is associated with an increased risk for development of Parkinson's disease, although not all results are uniform. The variability between these studies is likely due to differences in what components of air pollution are measured, timing and methods used to determine exposures, and correction for other variables. There are several potential mechanisms by which air pollution could act to increase the risk for development of Parkinson's disease, including direct neuronal toxicity, induction of systemic inflammation leading to central nervous system inflammation, and alterations in gut physiology and the microbiome. Taken together, air pollution is an emerging risk factor in the development of Parkinson's disease. A number of potential mechanisms have been implicated by which it promotes neuropathology providing biological plausibility, and these mechanisms are likely relevant to the development of other neurodegenerative disorders such as Alzheimer's disease. This field is in its early stages, but a better understanding of how environmental exposures influence the pathogenesis of neurodegeneration is essential for reducing the incidence of disease and finding disease-modifying therapies. © 2022 International Parkinson and Movement Disorder Society.

The efficacy of human papillomavirus vaccination in young Japanese girls: the interim results of the OCEAN study.

Human papillomavirus (HPV) vaccine has been used to prevent chronic HPV infection, which accounts for cervical cancer. Japanese Ministry of Health, Labor and Welfare (MHLW) conducted an HPV vaccination campaign in 2010 and the Obstetrical Gynecological Society of Osaka initiated a multicenter, prospective cohort study in Osaka, Japan - OCEAN (Osaka Clinical resEArch of HPV vacciNe) study - to investigate the oncogenic HPV prevalence and the long-term protection rate of HPV vaccine. A total of 2814 participants were enrolled on their visit for HPV vaccination between 12 and 18 years old. Among them, 102 participants received HPV/Pap co-test as primary cancer screening at the age of 20-21. We compared the prevalence in two groups (the vaccinated and the unvaccinated group). HPV infection ratio was significantly lower in the vaccinated group compared to the unvaccinated (12.9% vs. 19.7%; p = .04). In particular, HPV 16 and 18 were not detected in the vaccinated group, while 4.9% of participants in the unvaccinated group were infected (p = .001), suggesting that vaccination provided effective protection against high-risk types of HPV. The cross-protection effect of HPV vaccines was also observed against HPV 31, 45, and 52. Although HPV vaccines were not contributed to the reduction of cervical intraepithelial neoplasia 1 (CIN) (p = .28), CIN2 or worse was not observed in vaccinated group. Our research showed that at the age of 20-21, HPV vaccine inhibited the infection of high-risk HPV and had impacted on the development to CIN2 or worse in Japan.

Matrix Metalloproteinases in Human Decidualized Endometrial Stromal Cells.

Cyclic changes, such as growth, decidualization, shedding, and regeneration, in the human endometrium are regulated by the reciprocal action of female hormones, such as estradiol (E2), and progesterone (P4). Matrix metalloproteases (MMPs) and tissue inhibitors of MMPs (TIMPs) control the invasion of extravillous trophoblast cells after implantation. Several MMPs and TIMPs function in the decidua and endometrial stromal cells (ESCs). Here, we aimed to systematically investigate the changes in MMPs and TIMPs associated with ESC decidualization. We evaluated the expression of 23 MMPs, four TIMPs, and four anti-sense non-coding RNAs from MMP loci. Primary ESC cultures treated with E2 + medroxyprogesterone acetate (MPA), a potent P4 receptor agonist, showed significant down-regulation of MMP3, MMP10, MMP11, MMP12, MMP20, and MMP27 in decidualized ESCs, as assessed by quantitative reverse transcription PCR. Further, MMP15 and MMP19 were significantly upregulated in decidualized ESCs. siRNA-mediated silencing of Heart and Neural Crest Derivatives Expressed 2 (HAND2), a master transcriptional regulator in ESC decidualization, significantly increased MMP15 expression in untreated human ESCs. These results collectively indicate the importance of MMP15 and MMP19 in ESC decidualization and highlight the role of HAND2 in repressing MMP15 transcription, thereby regulating decidualization.

Transcriptional regulation of LGALS9 by HAND2 and FOXO1 in human endometrial stromal cells in women with regular cycles.

Uterine natural killer cells are regulated via surface inhibitory receptors for IL15 and galectin-9 (LGALS9) secreted by endometrial stromal cells (ESCs). However, the mechanism that regulates LGALS9 mRNA levels in ESCs is unclear. The aim of this study is to clarify the transcriptional regulation of LGALS9 in ESCs. Here, LGALS9 mRNA expression levels significantly decreased in the endometrial tissue in the early- to mid-secretory phase, and recovered in the mid- to late-secretory phase, compared to that in the proliferative phase. In ESCs, LGALS9 mRNA expression significantly decreased following estradiol + medroxyprogesterone acetate treatment for 1 day and increased after 12 days compared to that in the control. The transcriptional activity of the LGALS9 upstream region was upregulated by heart and neural crest derivatives expressed 2 (HAND2) and downregulated by forkhead box O1 (FOXO1). In ESCs, HAND2 expression significantly increased throughout the 12 days treatment with steroid hormones, whereas FOXO1 expression significantly increased on Day 1, reached a plateau, and significantly increased again after 6 days of treatment. Levels of FOXO1 phosphorylation (pFOXO1) remained unchanged after a 3-day treatment of ESCs with steroid hormones, but significantly increased following a 12-day treatment. pFOXO1 could not bind to the DNA and was thus unable to directly suppress LGALS9 transcription. Therefore, expression level of HAND2 and phosphorylation status of FOXO1 may determine LGALS9 mRNA expression. This study provides a novel molecular mechanism underlying the transcriptional regulation of LGALS9 mRNA in ESCs, which could be valuable in the treatment of diseases associated with decidualization failure.

Immune Tolerance of the Human Decidua.

The endometrium is necessary for implantation, complete development of the placenta, and a successful pregnancy. The endometrium undergoes repeated cycles of proliferation, decidualization (differentiation), and shedding during each menstrual cycle. The endometrium-including stromal, epithelial, vascular endothelial, and immune cells-is both functionally and morphologically altered in response to progesterone, causing changes in the number and types of immune cells. Immune cells make up half of the total number of endometrial cells during implantation and menstruation. Surprisingly, immune tolerant cells in the endometrium (uterine natural killer cells, T cells, and macrophages) have two conflicting functions: to protect the body by eliminating pathogenic microorganisms and other pathogens and to foster immunological change to tolerate the embryo during pregnancy. One of the key molecules involved in this control is the cytokine interleukin-15 (IL-15), which is secreted by endometrial stromal cells. Recently, it has been reported that IL-15 is directly regulated by the transcription factor heart- and neural crest derivatives-expressed protein 2 in endometrial stromal cells. In this review, we outline the significance of the endometrium and immune cell population during menstruation and early pregnancy and describe the factors involved in immune tolerance and their involvement in the establishment and maintenance of pregnancy.

Exposure to cigarette smoke affects endometrial maturation including angiogenesis and decidualization.

PURPOSE: To elucidate the effects of cigarette smoking on human endometrial maturation for reproductive function, the authors examined the in vitro effects of cigarette smoke extract (CSE) on angiogenesis and decidualization in primary human endometrial stromal cells (ESCs). METHODS: Endometrial stromal cells were cultured with CSE and/or estradiol-17ß (E2) and medroxyprogesterone acetate (MPA). The mRNA, protein levels, and protein secretion of the angiogenic factors and decidual specific factors were assessed using real-time polymerase chain reaction, Western blot analysis, and enzyme-linked immunosorbent assay, respectively. Decidualization was also monitored by the changes in cellular morphology. RESULTS: Endometrial stromal cell proliferation substantially decreased after dose-dependent treatments with CSE at concentrations above 1%, whereas cell death was induced at treatment concentrations above 1% CSE. Treatments above 0.025% CSE led to increased vascular endothelial growth factor mRNA through hypoxia-inducible factor-1α accumulation. CSE concentrations at 0.01% and 0.025% increased the prolactin expression levels after treatment with E2 and MPA, whereas 0.1% and 0.25% CSE concentrations suppressed prolactin. Similar tendencies were observed in cellular morphology and other decidual specific factors. CONCLUSION: These results suggest that exposure to cigarette smoke affects endometrial appropriate maturation including the processes of angiogenesis and decidualization in the reproductive system.

A survey of 20-year-old Japanese women: how is their intention to undergo cervical cancer screening associated with their childhood HPV vaccination status?

INTRODUCTION: In Japan, two groups of women, HPV vaccinated and unvaccinated, are approaching age 20, when they should begin cervical cancer screening. To improve Japan's current poor cervical cancer screening rate, we need to know how these women are thinking about screening. METHODS: We conducted an internet survey of 20-y-old women, exploring their understanding of HPV and cervical cancer screening. We then gave them leaflets with basic information about HPV and cervical cancer, stressing the importance of early detection by screening. We analyzed the leaflet's effects on their attitudes based on their vaccination status. RESULTS: Our study of 618 women found a significantly higher intention for engagement for cervical cancer screening in women HPV-vaccinated as teenagers (29% versus 17%). They were also more aware that: (1) HPV is transmitted by sexual intercourse (49.1% versus 39.2%); (2) the HPV vaccine prevents cervical cancer (49.0% to 34.0%); and (3) the appropriate cervical cancer screening interval is every 2 y (63.3% versus 56.2%). Women in both groups responded well to the leaflet, with significant improvements in intention to receive screening. However, 65%-67% were not swayed. DISCUSSION: HPV-vaccinated women were more knowledgeable about cervical cancer and had a greater intention to receive screening. Our educational leaflet was moderately effective in both groups for increasing intentions to screen, but the majority in both groups were still resistant to screening. CONCLUSION: Japan needs to develop more effective educational programs and tools to vigorously impart the importance of cervical cancer screening.

Studying the Pathophysiology of Parkinson's Disease Using Zebrafish.

Parkinson's disease is a common neurodegenerative disorder leading to severe disability. The clinical features reflect progressive neuronal loss, especially involving the dopaminergic system. The causes of Parkinson's disease are slowly being uncovered and include both genetic and environmental insults. Zebrafish have been a valuable tool in modeling various aspects of human disease. Here, we review studies utilizing zebrafish to investigate both genetic and toxin causes of Parkinson's disease. They have provided important insights into disease mechanisms and will be of great value in the search for disease-modifying therapies.

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.

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.

A survey of Japanese mothers on the effectiveness of the Ministry of Health, Labor and Welfare's revised HPV vaccine leaflet.

Introduction: In June of 2013, Japan's Ministry of Health, Labor and Welfare (MHLW) suspended its position of strong recommendation for the routine immunization of young girls against the Human Papilloma Virus (HPV) because of reports of adverse reactions after the vaccination. For the next four years, the MHLW's website warned about the significance of these adverse events. In January of 2018, MHLW's website was modified to reflect a less negative stance. We have studied public awareness of MHLW's revised leaflet in Japanese women whose daughters were of the targeted age for receiving the HPV vaccine and how this awareness influenced their intentions to get their daughters vaccinated. Materials and Methods: From June to December of 2018, a survey was conducted through the Departments of Obstetrics and Gynecology at 14 different medical facilities. The questionnaire was distributed to women whose daughters were of the HPV-vaccine-targeted age. The survey measured their responses before and after being presented with the 2018-revised MHLW leaflet. Responses from 384 mothers were analyzed. Results: Before being presented with the leaflet, the survey found that the percentage of responder's daughters already vaccinated was 6.5% (24/372). After reading the MHLW leaflet, an additional 6.9% (24/346) responded "I want to get my daughter vaccinated immediately", and 37.6% (130/346) responded "I have positive feelings about HPV vaccination". Discussion: By presenting the new MHLW leaflet at obstetrics and gynecology facilities, we expect to be able to effectively increase the HPV vaccination rate in Japan.

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.

Diesel Exhaust Extract Exposure Induces Neuronal Toxicity by Disrupting Autophagy.

The vast majority of neurodegenerative disease cannot be attributed to genetic causes alone and as a result, there is significant interest in identifying environmental modifiers of disease risk. Epidemiological studies have supported an association between long-term exposure to air pollutants and disease risk. Here, we investigate the mechanisms by which diesel exhaust, a major component of air pollution, induces neurotoxicity. Using a zebrafish model, we found that exposure to diesel exhaust particulate extract caused behavioral deficits and a significant decrease in neuron number. The neurotoxicity was due, at least in part, to reduced autophagic flux, which is a major pathway implicated in neurodegeneration. This neuron loss occurred alongside an increase in aggregation-prone neuronal protein. Additionally, the neurotoxicity induced by diesel exhaust particulate extract in zebrafish was mitigated by co-treatment with the autophagy-inducing drug nilotinib. This study links environmental exposure to altered proteostasis in an in vivo model system. These results shed light on why long-term exposure to traffic-related air pollution increases neurodegenerative disease risk and open up new avenues for exploring therapies to mitigate environmental exposures and promote neuroprotection.

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.

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.

Decidualization of the human endometrium.

BACKGROUND: Decidualization of the human endometrium, which involves a dramatic morphological and functional differentiation of human endometrial stromal cells (ESCs), is essential for the establishment of a successful pregnancy. Decidualization results from a complex interplay of transcription factors, morphogens, cytokines, cell cycle regulators, and signaling pathways. METHODS: Based on a literature review, the regulation of, and the molecular mechanisms involved in, the decidualization of the endometrium are described. MAIN FINDINGS: Progesterone, together with proteins that are regulated by progesterone and/or cyclic adenosine monophosphate, including homeobox A10, forkhead box O1, signal transducers and activators of transcription, and heart and neural crest derivatives expressed transcript 2, forms a critical network for ESC decidualization and is a prerequisite to successful implantation. Decidualized ESCs contribute to the microenvironment at the feto-maternal interface and its direct or indirect influence on extracellular matrix remodeling, regulation of the local immune response, anti-oxidative stress, and angiogenesis (vascular maturation). Impairment of this process is associated with a variety of pregnancy disorders, including infertility, recurrent miscarriages, and uteroplacental disorders. CONCLUSION: A deeper understanding of the process of decidualization is expected to provide new insights into the fields of reproductive biology and reproductive medicine.