CD34 and CD49f Double-Positive and Lineage Marker-Negative Cells Isolated from Human Myometrium Exhibit Stem Cell-Like Properties Involved in Pregnancy-Induced Uterine Remodeling.

Repeated and dramatic pregnancy-induced uterine enlargement and remodeling throughout reproductive life suggests the existence of uterine smooth muscle stem/progenitor cells. The aim of this study was to isolate and characterize stem/progenitor-like cells from human myometrium through identification of specific surface markers. We here identify CD49f and CD34 as markers to permit selection of the stem/progenitor cell-like population from human myometrium and show that human CD45(-) CD31(-) glycophorin A(-) and CD49f(+) CD34(+) myometrial cells exhibit stem cell-like properties. These include side population phenotypes, an undifferentiated status, high colony-forming ability, multilineage differentiation into smooth muscle cells, osteoblasts, adipocytes, and chondrocytes, and in vivo myometrial tissue reconstitution following xenotransplantation. Furthermore, CD45(-) CD31(-) glycophorin A(-) and CD49f(+) CD34(+) myometrial cells proliferate under hypoxic conditions in vitro and, compared with the untreated nonpregnant myometrium, show greater expansion in the estrogen-treated nonpregnant myometrium and further in the pregnant myometrium in mice upon xenotransplantation. These results suggest that the newly identified myometrial stem/progenitor-like cells influenced by hypoxia and sex steroids may participate in pregnancy-induced uterine enlargement and remodeling, providing novel insights into human myometrial physiology.

Studies using an in vitro model show evidence of involvement of epithelial-mesenchymal transition of human endometrial epithelial cells in human embryo implantation.

Human embryo implantation is a critical multistep process consisting of embryo apposition/adhesion, followed by penetration and invasion. Through embryo penetration, the endometrial epithelial cell barrier is disrupted and remodeled by an unknown mechanism. We have previously developed an in vitro model for human embryo implantation employing the human choriocarcinoma cell line JAR and the human endometrial adenocarcinoma cell line Ishikawa. Using this model we have shown that stimulation with ovarian steroid hormones (17ß-estradiol and progesterone, E2P4) and suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, enhances the attachment and adhesion of JAR spheroids to Ishikawa. In the present study we showed that the attachment and adhesion of JAR spheroids and treatment with E2P4 or SAHA individually induce the epithelial-mesenchymal transition (EMT) in Ishikawa cells. This was evident by up-regulation of N-cadherin and vimentin, a mesenchymal cell marker, and concomitant down-regulation of E-cadherin in Ishikawa cells. Stimulation with E2P4 or SAHA accelerated Ishikawa cell motility, increased JAR spheroid outgrowth, and enhanced the unique redistribution of N-cadherin, which was most prominent in proximity to the adhered spheroids. Moreover, an N-cadherin functional blocking antibody attenuated all events but not JAR spheroid adhesion. These results collectively provide evidence suggesting that E2P4- and implanting embryo-induced EMT of endometrial epithelial cells may play a pivotal role in the subsequent processes of human embryo implantation with functional control of N-cadherin.

Possible involvement of nerve growth factor in dysmenorrhea and dyspareunia associated with endometriosis.

Nerve growth factor (NGF) has been recently proposed as one of the key factors responsible not only for promotion of nerve fiber growth but also for the onset and maintenance of pain in a variety of diseases. The aim of this study was to investigate the role of NGF in the pelvic pain associated with endometriosis. Tissue and peritoneal fluid samples were collected from 95 women with laparoscopically and histopathologically confirmed endometriosis and 59 control women without endometriosis. Expression levels of NGF mRNA and protein were examined using real-time RT-PCR and immunohistochemistry, respectively. Concentration of NGF in the peritoneal fluid (PF-NGF) was measured using ELISA. The degree of dyspareunia and dysmenorrhea was evaluated using a verbal rating scale. Real-time RT-PCR analysis revealed that NGF mRNA was significantly more abundant in the ovarian endometriomas and peritoneal endometriosis than in the normal control endometrium. Immunohistochemical analyses demonstrated that NGF was prominently expressed and preferentially localized to the glands of the ovarian endometriomas and peritoneal endometriosis, whereas it was only weakly detectable in the normal endometrium. Although PF-NGF was undetectable in some normal subjects and endometriosis patients, elevated PF-NGF in the peritoneal fluid was more frequently observed in endometriosis patients with severe pain than in those with less severe pain. Our results suggest that NGF produced locally in the peritoneal cavity may be involved in the generation of endometriosis-associated pelvic pain.

Congenitally corrected transposition of the great arteries.

Congenitally corrected transposition of the great arteries (cTGA) is an uncommon cardiac malformation characterized by discordant atrioventricular and ventriculoarterial connections. Most cases of cTGA are associated with cardiac anomalies. As the ventricular outflow tract may appear to arise correctly from the right and left ventricles, cases of cTGA with a mild associated anomaly are rarely detected prenatally. Parallel vessels are evident in cTGA, but this sign is also present in complete TGA. We report a case of cTGA diagnosed in utero at 29 weeks' gestation. The fetus was diagnosed as TGA and referred to our hospital at 28 weeks' gestation. cTGA was found at 29 weeks' gestation in our hospital, and no additional cardiac anomalies were seen prenatally. After birth, patent ductus arteriosus with bidirectional flow was present. Careful examination of the four-chamber view suggested atrioventricular discordance. Identification of a parallel course of the great vessels, with the aorta anterior and to the left of the pulmonary trunk (l-transposition), may help accurate prenatal diagnosis of cTGA.

Exponential increase of the gestational-age-specific incidence of preeclampsia onset (COPE study): a multicenter retrospective cohort study in women with maternal check-ups at <20 weeks of gestation in Japan.

According to the 2004 Japanese definition, early-onset (EO) preeclampsia (PE) is defined as PE occurring at <32 weeks of gestation. This was based on the presence of "dual peaks" (30-31 and 34-35 weeks) in the prevalence of severe forms of hypertension. In contrast, the international definition adopted a cutoff of 34 weeks based on the consensus. Our aim was to investigate whether there were "dual peaks" in the gestational-age-specific incidence or prevalence of PE onset in pregnant women who underwent maternal check-ups at <20 weeks of gestation in a multicenter retrospective cohort study. Diagnoses of PE and superimposed preeclampsia (SPE) were based on the new Japanese definition. A total of 26,567 pregnant women with singleton pregnancy were investigated. The best fitting equations for the distribution of the onset of gestational-age-specific incidence (hazard) rates of PE/SPE, PE, and PE with severe hypertension (a systolic blood pressure ≥160 and/or a diastolic blood pressure ≥110 mmHg) were investigated using the curve estimation function in SPSS. PE/SPE occurred in 1.83% of the patients. EO-PE/SPE with onset at <32 and <34 weeks of gestation and preterm PE/SPE occurred in 0.38, 0.56, and 1.07% of the patients, respectively. Gestational-age-specific incidence rates of PE/SPE, PE, and PE with severe hypertension showed exponential increases, with very high R2 values (0.975, 0.976, and 0.964, respectively). There were no "dual peaks" in the prevalence rates of women with SPE/PE, PE, and PE with severe hypertension. In conclusion, the absence of "dual peaks" refutes the previous rationale of EO-PE being defined as PE at <32 weeks of gestation. Further studies to determine an appropriate definition of EO-PE/SPE are needed.

The UDP-glucose receptor P2RY14 triggers innate mucosal immunity in the female reproductive tract by inducing IL-8.

Innate mucosal immune responses, including recognition of pathogen-associated molecular patterns through Toll-like receptors, play an important role in preventing infection in the female reproductive tract (FRT). Damaged cells release nucleotides, including ATP and uridine 5'-diphosphoglucose (UDP-glucose), during inflammation and mechanical stress. We show in this report that P2RY14, a membrane receptor for UDP-glucose, is exclusively expressed in the epithelium, but not the stroma, of the FRT in humans and mice. P2RY14 and several proinflammatory cytokines, such as IL-8, are up-regulated in the endometria of patients with pelvic inflammatory disease. UDP-glucose stimulated IL-8 production via P2RY14 in human endometrial epithelial cells but not stromal cells. Furthermore, UDP-glucose enhanced neutrophil chemotaxis in the presence of a human endometrial epithelial cell line in an IL-8-dependent manner. Administration of UDP-glucose into the mouse uterus induced expression of macrophage inflammatory protein-2 and keratinocyte-derived cytokine, two murine chemokines that are functional homologues of IL-8, and augmented endometrial neutrophil recruitment. Reduced expression of P2RY14 by small interfering RNA gene silencing attenuated LPS- or UDP-glucose-induced leukocytosis in the mouse uterus. These results suggest that UDP-glucose and its receptor P2RY14 are key front line players able to trigger innate mucosal immune responses in the FRT bypassing the recognition of pathogen-associated molecular patterns. Our findings would significantly impact the strategic design of therapies to modulate mucosal immunity by targeting P2RY14.

Activation of SRC kinase and phosphorylation of signal transducer and activator of transcription-5 are required for decidual transformation of human endometrial stromal cells.

Progesterone induces decidual transformation of estrogen-primed human endometrial stromal cells (hESCs), critical for implantation and maintenance of pregnancy, through activation of many signaling pathways involving protein kinase A and signal transducer and activator of transcription (STAT)-5. We have previously shown that kinase activation of v-src sarcoma (Schmidt-Ruppin A-2) viral oncogene homolog (SRC) kinase is closely associated with decidualization and that SRC is indispensable for maximal decidualization in mice. To address whether SRC kinase activity is essential for decidualization in humans, hESCs were infected with adenoviruses carrying enhanced green fluorescent protein alone (Ad-EGFP), a kinase-inactive dominant-negative mutant (Ad-SRC/K295R), or an inactive autophosphorylation site mutant (Ad-SRC/Y416F). The cells were cultured in the presence of estradiol and progesterone (EP) to induce decidualization and subjected to RT-PCR, immunoblot, and ELISA analyses. Ad-EGFP-infected hESCs exhibited decidual transformation and up-regulation of decidualization markers including IGF binding protein 1 and prolactin in response to 12-d treatment with EP. In contrast, hESCs infected with Ad-SRC/K295R remained morphologically fibroblastoid without production of IGF binding protein 1 and prolactin even after EP treatment. Ad-SRC/Y416F displayed similar but less inhibitory effects on decidualization, compared with Ad-SRC/K295R. During decidualization, STAT5 was phosphorylated on tyrosine 694, a well-known SRC phosphorylation site. Phosphorylation was markedly attenuated by Ad-SRC/K295R but not Ad-EGFP. These results indicate that the SRC-STAT5 pathway is essential for decidualization of hESCs.

Glycodelin blocks progression to S phase and inhibits cell growth: a possible progesterone-induced regulator for endometrial epithelial cell growth.

Prolonged exposure to unopposed estrogen in the absence of progesterone gives rise to endometrial hyperplasia and carcinoma. Post-ovulatory progesterone is necessary for the proper growth and differentiation of endometrial epithelial cells (EECs). Progesterone exposure induces the endometrial production of numerous bioactive substances, one of which is the glycoprotein, glycodelin (Gd). We investigated the role of Gd in cell cycle progression and cell growth to better understand how Gd affects EEC behavior and endometrial cancer pathogenesis. Ishikawa cells, a well-differentiated human endometrial epithelial cancer cell line, were transfected with expression plasmids encoding enhanced green fluorescent protein (EGFP) or EGFP-fused Gd (EGFP-Gd). They were then subjected to a cell proliferation assay, flow cytometry cell cycle analysis and RT-PCR analysis of cyclin-dependent kinase inhibitors (CDKIs) including p21, p27 and p16. Overexpression of EGFP-Gd resulted in a reduction of cell proliferation activity, an accumulation of G1-phase cells and up-regulation of p21, p27 and p16 mRNAs. Furthermore, progesterone-induced inhibition of Ishikawa cell growth was partially attenuated by Gd knockdown using siRNA. These results indicate that Gd causes inhibition of G1/S progression together with up-regulation of CDKIs thereby reducing cell growth. Thus, progesterone-induced expression of Gd may, at least in part, contribute to the suppression of endometrial epithelial growth observed during the secretory phase.

Molecular analysis of a mutated FSH receptor detected in a patient with spontaneous ovarian hyperstimulation syndrome.

Spontaneous ovarian hyperstimulation syndrome (sOHSS) is a rare event that may result from a FSH-producing pituitary adenoma (FSHoma), activating mutations of the FSH receptor (FSHR), and cross-reactivity of the FSHR to elevated hCG and TSH in the setting of pregnancy or hypothyroidism. The objective of this study was to investigate whether an aberrant FSHR was present in a woman with sOHSS and a non-surgically diagnosed FSHoma whose serum FSH levels and FSH bioactivity were nearly normal. Sequencing of the patient's FSHR gene revealed a heterozygous novel missense mutation c. 1536G>A resulting in an amino acid substitution M512I. We asked whether this mutant FSHR affected FSHR-mediated signaling pathways involving cAMP/protein kinase A (PKA), phosphatidylinositol-3 kinase (PI3K)/protein kinase B (AKT) and v-src sarcoma (Schmidt-Ruppin A-2) viral oncogene homolog kinase (SRC)/ p42/p44 extracellular signal-regulated protein kinases (ERK1/2). Thus, 293T cells expressing wild-type (FSHRwt), the mutant FSHR (FSHRmt), or both (FSHRwt/mt) were treated with FSH and subjected to measurements of intracellular cAMP, cAMP-induced CRE (cAMP response element)-mediated luciferase assays and immunoblot analyses of phosphorylated PI3K and ERK1/2. There were no differences in luciferase activities or phosphorylation levels of ERK1/2 among FSHRwt, FSHRmt cells and FSHwt/mt cells. However, FSHRmt cells showed a significant reduction in both cAMP production and PI3K phosphorylation levels with unchanged phosphorylation of ERK1/2 upon FSH stimulation in comparison to FSHwt cells. Also, FSH treatment did not provoke PI3K phosphorylation in FSHwt/mt cells. These results indicate that the novel missense M512I FSHR mutation identified herein did not participate in hyperactivation of FSHR-mediated signaling pathways but rather in hypoactivation of the FSH-mediated PI3K/AKT pathway. Thus, this study demonstrates a new functional property of this novel mutatnt FSHR, which, however, might not be involved in the pathogenesis of sOHSS in this FSHoma patient.

Online tool for calculating null points in various inversion recovery sequences.

Accurate equations for calculating the inversion time of the null point (TInull) in inversion recovery (IR) sequences are required for adequate suppression of fat or cerebrospinal fluid (CSF) but are not widely known. The purpose of this study is to elucidate the process of deriving accurate TInull equations using schematic diagrams that allow the equations to be easily understood, and to devise a convenient online tool for instant calculation of TInull. We investigated various IR sequences in which a 180° inversion pulse is followed by spin echo (SE) type sequences, termed IR-SE-type sequences, including FLAIR (fluid attenuated inversion recovery), STIR (short inversion time inversion recovery), and SPAIR (spectral adiabatic inversion recovery, spectral attenuated inversion recovery). We classified these sequences into three types according to the behavior of the longitudinal magnetization before the next IR pulse: having a train of multiple spin echoes, a single spin echo, or a train of multiple inversions by SPAIR pulses (with no spin echo). For each sequence type, we produced a precise diagram of the behavior of the longitudinal magnetization and clarified the process of deriving the equation for TInull. Three accurate TInull equations were derived. We created an online tool that calculates TInull using these three equations. The validity of the resulting TInull was evaluated on pelvic SPAIR diffusion-weighted (DW) images at 3T in 21 volunteers, using various inversion times (TI) around the calculated TInull. The tool displays the calculated TInull value instantly, after inputting imaging parameters and the T1 values of fat or CSF. The TInull values calculated using the tool achieved sufficient suppression in all subjects. When the actual TI value differed by more than 5% from the calculated TInull value, the fat suppression effect was significantly less on pelvic SPAIR DW images (P<0.01). In conclusion, this online tool is easily available and enables adequate suppression of fat or CSF according to the imaging parameters.

Stem cell-like differentiation potentials of endometrial side population cells as revealed by a newly developed in vivo endometrial stem cell assay.

BACKGROUND: Endometrial stem/progenitor cells contribute to the cyclical regeneration of human endometrium throughout a woman's reproductive life. Although the candidate cell populations have been extensively studied, no consensus exists regarding which endometrial population represents the stem/progenitor cell fraction in terms of in vivo stem cell activity. We have previously reported that human endometrial side population cells (ESP), but not endometrial main population cells (EMP), exhibit stem cell-like properties, including in vivo reconstitution of endometrium-like tissues when xenotransplanted into immunodeficient mice. The reconstitution efficiency, however, was low presumably because ESP cells alone could not provide a sufficient microenvironment (niche) to support their stem cell activity. The objective of this study was to establish a novel in vivo endometrial stem cell assay employing cell tracking and tissue reconstitution systems and to examine the stem cell properties of ESP through use of this assay. METHODOLOGY/PRINCIPAL FINDINGS: ESP and EMP cells isolated from whole endometrial cells were infected with lentivirus to express tandem Tomato (TdTom), a red fluorescent protein. They were mixed with unlabeled whole endometrial cells and then transplanted under the kidney capsule of ovariectomized immunodeficient mice. These mice were treated with estradiol and progesterone for eight weeks and nephrectomized. All of the grafts reconstituted endometrium-like tissues under the kidney capsules. Immunofluorescence revealed that TdTom-positive cells were significantly more abundant in the glandular, stromal, and endothelial cells of the reconstituted endometrium in mice transplanted with TdTom-labeled ESP cells than those with TdTom-labeled EMP cells. CONCLUSIONS/SIGNIFICANCE: We have established a novel in vivo endometrial stem cell assay in which multi-potential differentiation can be identified through cell tracking during in vivo endometrial tissue reconstitution. Using this assay, we demonstrated that ESP cells differentiated into multiple endometrial lineages in the niche provided by whole endometrial cells, indicating that ESP cells are genuine endometrial stem/progenitor cells.

Stem cell-like properties of the endometrial side population: implication in endometrial regeneration.

BACKGROUND: The human endometrium undergoes cyclical regeneration throughout a woman's reproductive life. Ectopic implantation of endometrial cells through retrograde menstruation gives rise to endometriotic lesions which affect approximately 10% of reproductive-aged women. The high regenerative capacity of the human endometrium at eutopic and ectopic sites suggests the existence of stem/progenitor cells and a unique angiogenic system. The objective of this study was to isolate and characterize putative endometrial stem/progenitor cells and to address how they might be involved in the physiology of endometrium. METHODOLOGY/PRINCIPAL FINDINGS: We found that approximately 2% of the total cells obtained from human endometrium displayed a side population (SP) phenotype, as determined by flow cytometric analysis of Hoechst-stained cells. The endometrial SP (ESP) cells exhibited preferential expression of several endothelial cell markers compared to endometrial main population (EMP) cells. A medium specific for endothelial cell culture enabled ESP cells to proliferate and differentiate into various types of endometrial cells, including glandular epithelial, stromal and endothelial cells in vitro, whereas in the same medium, EMP cells differentiated only into stromal cells. Furthermore, ESP cells, but not EMP cells, reconstituted organized endometrial tissue with well-delineated glandular structures when transplanted under the kidney capsule of severely immunodeficient mice. Notably, ESP cells generated endothelial cells that migrated into the mouse kidney parenchyma and formed mature blood vessels. This potential for in vivo angiogenesis and endometrial cell regeneration was more prominent in the ESP fraction than in the EMP fraction, as the latter mainly gave rise to stromal cells in vivo. CONCLUSIONS/SIGNIFICANCE: These results indicate that putative endometrial stem cells are highly enriched in the ESP cells. These unique characteristics suggest that ESP cells might drive physiological endometrial regeneration and be involved in the pathogenesis of endometriosis.

Glucagon receptor expression and glucagon stimulation of ghrelin secretion in rat stomach.

The present study was performed to evaluate the role of glucagon in the regulation of ghrelin secretion from the rat stomach. mRNA for ghrelin and glucagon receptor was expressed predominantly in the lower body and pylorus of stomach, but little or not in the upper body and cardia. Ghrelin- and glucagon receptor-immunoreactive cells were detected in lamina propria mucosae of stomach and some cells expressed both. Intravenous administration of glucagon caused transient increases in both acyl- and desacyl-ghrelin levels in the gastric vein within 10 min, which was followed by gradual increases in desacyl-ghrelin levels until 60 min. Steady state levels of ghrelin mRNA in the stomach were increased by 1.9-fold 20 min after glucagon administration, but not at 5 or 120 min. These results suggest that glucagon stimulates acute release of both forms of ghrelin and thereafter upregulates synthesis and release of desacyl-ghrelin in the rat stomach.

Histone deacetylase inhibitor-induced glycodelin enhances the initial step of implantation.

BACKGROUND: The complex molecular pathways governing implantation are unclear and ethical limitations limit studies in humans. Reversible histone acetylation regulates gene transcription and histone deacetylase inhibitors (HDACI) induce specific genes. Suberoylanilide hydroxamic acid (SAHA), a HDACI recently approved as an anti-cancer drug, induces the morphological and functional differentiation of human endometrial gland cells through up-regulation of glycodelin, a secretory phase dominant protein. METHODS: We investigated whether SAHA improves implantation in an in vitro implantation assay using the human endometrial adenocarcinoma cell line, Ishikawa and the choriocarcinoma cell line, JAR. RESULTS: In an in vitro implantation assay, JAR spheroids attached and adhered to Ishikawa cells in a time dependent manner. Glycodelin induction, following treatment with ovarian steroid hormones or SAHA, enhanced implantation. The improvement in implantation was also obtained when glycodelin was overexpressed without stimulation and was almost completely abrogated by glycodelin gene silencing. CONCLUSIONS: This study demonstrates that glycodelin is a key regulatory protein of implantation and suggests that SAHA may have a capacity to supplant steroid derivatives in the treatment of infertility.