Xing-Hong Ma

Differential Expression of Microsomal Prostaglandin E Synthase at Implantation Sites and in Decidual Cells of Mouse Uterus

Abstract Prostaglandin E2 (PGE2) is considered important for blastocyst spacing, implantation, and decidualization in the rodent uterus. PGE synthase (PGES) catalyzes the isomerization of PGH2 to PGE2. There are two isoforms of PGES, microsomal PGES (mPGES) and cytosolic PGES (cPGES). However, the expression and regulation of mPGES in the mammalian uterus during early pregnancy are still unknown. The aim of this study was to investigate the differential expression of mPGES in mouse uterus during early pregnancy and its regulation under different conditions by in situ hybridization and immunohistochemistry. Microsomal PGES expression in the preimplantation mouse embryos was also performed by reverse transcription polymerase chain reaction (RT-PCR). Expression of mPGES mRNA and protein was at a basal level in the luminal epithelium from Day 1 to Day 4 of pregnancy. However, mPGES mRNA and protein were highly expressed in the stroma immediately surrounding the blastocyst but not in the luminal epithelium on Day 5 of pregnancy. Microsomal PGES mRNA and protein were not detected in the pseudopregnant uterus from Day 1 to Day 5. During delayed implantation, mPGES mRNA and protein were also not detected in the uterus. Once delayed implantation was terminated by estrogen treatment and embryo implantation initiated, both mPGES mRNA and protein were induced to express in the stroma immediately surrounding the blastocyst, which was similar to the expression pattern on Day 5 of pregnancy. From Day 6 to Day 8 of pregnancy, the signals for mPGES mRNA and protein were strongly detected in the decidualized cells. Microsomal PGES mRNA and protein were also highly expressed in the artificially decidualized cells but not in the control horn. Microsomal PGES mRNA was detected in the oocytes and all the stages of preimplantation embryos. The strong mPGES expression in the implantation site and decidual cells suggests that mPGES might play an important role during implantation and more importantly in decidualization.

Serial Analysis of Gene Expression in Mouse Uterus at the Implantation Site

Although oligonucleotide chips, cDNA microarrays, differential display reverse transcription-PCR, and other approaches have been used to screen implantation-related molecules, the mechanism by which embryo implantation occurs is still unknown. The aim of this study was to profile the differential gene expression between interimplantation site and implantation site in mouse uterus on day 5 of pregnancy by serial analysis of gene expression (SAGE). In our two SAGE libraries of 11-bp tags, the total numbers of tags sequenced were 48,121 for the interimplantation site and 50,227 for the implantation site. There were 1,039 tags specifically expressed at interimplantation site, and 1,252 tags specifically expressed at the implantation site. Based on the p value, there were 195 tags significantly up-regulated at the interimplantation site and 261 tags significantly up-regulated at the implantation site, of which 100 genes were single matched at the interimplantation site and 127 genes were single matched at the implantation site, respectively. By reverse transcription-PCR, the tag ratio between the implantation site and interimplantation site was verified on 14 significantly changed genes. Using in situ hybridization, 1810014L12Rik, Psmb5, Cd63, Npm1, Fads3, and Tagln2 were shown to be highly expressed at the implantation site compared with the interimplantation site. Compared with the interimplantation site, Ddx39 was strongly expressed in the subluminal stromal cells at the implantation site on day 5 of pregnancy. Ddx39 expression at the implantation site was specifically induced by active blastocysts. Additionally, Ddx39 expression was significantly up-regulated by estrogen in the ovariectomized mice. In our SAGE data, many implantation-related genes were identified in mouse uterus. Our data could be a valuable source for future study on embryo implantation.

Polyamines are essential in embryo implantation: Expression and function of polyamine-related genes in mouse uterus during peri-implantation period

Polyamines are key regulators in cell growth and differentiation. It has been shown that ornithine decarboxylase (Odc) was essential for post-implantation embryo development, and overexpression of spermidine/spermine N1-acetyltransferase will lead to ovarian hypofunction and hypoplastic uteri. However, the expression and function of polyamine-related genes in mouse uterus during early pregnancy are still unknown. In this study we investigated the expression, regulation, and function of polyamine-related genes in mouse uterus during the peri-implantation period. Odc expression was strongly detected at implantation sites and stimulated by estrogen treatment. The expression of Odc antizyme 1 and spermidine/spermine N1-acetyltransferase was also highly shown at implantation sites and regulated by Odc or polyamine level in uterine cells. Embryo implantation was significantly inhibited by alpha-difluoromethylornithine, an Odc inhibitor. Moreover, the reduction of Odc activity caused by alpha-difluoromethylornithine treatment was compensated by the up-regulation of S-adenosylmethionine decarboxylase gene expression. Collectively, our results indicated that the coordinated expression of uterine polyamine-related genes may be important for embryo implantation.

Expression and Regulation of Cytosolic Prostaglandin E Synthase in Mouse Uterus During the Peri-Implantation Period

Abstract Prostaglandin E2 (PGE2) is considered important for blastocyst spacing, implantation, and decidualization in rodent uteri. PGE synthase (PGES) catalyzes the isomerization of PGH2 to PGE2. Two isoforms of PGES exist: microsomal PGES (mPGES) and cytosolic PGES (cPGES); however, the expression and regulation of cPGES in the mammalian uterus during early pregnancy are still unknown. The aim of this study was to investigate the differential expression of cPGES in mouse uterus during early pregnancy and its regulation under different conditions using in situ hybridization and immunohistochemistry. A strong level of cPGES mRNA signal was exhibited in the stromal cells at the implantation site on Day 5 of pregnancy, whereas cPGES immunostaining was strongly detected in the luminal epithelium. The signals for both cPGES mRNA and immunostaining were strongly detected in the decidualized cells from Days 6–8 of pregnancy. A basal level of cPGES mRNA signal and immunostaining was exhibited in the uterus in delayed implantation. After delayed implantation was terminated by estrogen treatment and embryo implantation was initiated, cPGES mRNA signal was strongly detected in the stroma underlying the luminal epithelium at the implantation site, and cPGES immunostaining was strongly observed in the luminal epithelium surrounding the implanting blastocyst. A strong cPGES mRNA signal and immunostaining were detected in decidualized cells under artificial decidualization, whereas only a basal level of cPGES mRNA signal and immunostaining were observed in the control horn. Our data suggest that cPGES may play an important role during implantation and decidualization.

Expression and Regulation of Lipocalin-Type Prostaglandin D Synthase in Rat Testis and Epididymis

Abstract Lipocalin-type prostaglandin D synthase (L-PGDS), a bifunctional protein, is expressed in the male reproductive organs of many species. However, the expression and regulation of L-PGDS in rat are still uncertain. The present study investigated the regionalization and regulation of L-PGDS expression in rat testis and epididymis by in situ hybridization and immunohistochemistry under the conditions of sexual maturation, castration, and ethylene dimethane sulfonate (EDS) treatments. In sexually mature rats, L-PGDS mRNA was weakly expressed only in the testicular peritubular cells, whereas L-PGDS immunostaining was highly detected in the Leydig cells by Day 70 postpartum. During sexual maturation, L-PGDS mRNA expression was highly detected in the caput, corpus, and cauda of the epididymis 70 days after birth. Compared with normal L-PGDS expression in adult epididymis, both L-PGDS mRNA expression and protein immunostaining were significantly reduced in the caput, corpus, and cauda epididymis after castration. Testosterone propionate treatment induced a significant increase of L-PGDS expression in the epididymis of castrated rats. Compared with adult rat epididymis, L-PGDS mRNA and protein expression was down-regulated after EDS treatment. Testosterone propionate treatment could induce an increase of L-PGDS mRNA and protein expression in the epididymis of EDS-treated rats. In conclusion, both castration and EDS treatments caused a significant decrease of L-PGDS expression in the epididymis, whereas testosterone propionate treatment could induce an increase of L-PGDS expression in the epididymis of both castrated and EDS-treated rats, indicating that L-PGDS expression in the rat epididymis can be up-regulated by testosterone.

L-prostaglandin D synthase expression and regulation in mouse testis and epididymis during sexual maturation and testosterone treatment after castration.

Lipocalin-type prostaglandin D synthase (L-PGDS) is highly expressed in the adult testis and epididymis of many mammals. The present study was to investigate L-PGDS expression in mouse testis and epididymis during sexual maturation, and the effects of testoster-one replacement on L-PGDS expression in epididymis by in situ hybridization and immunohistochemistry. Both L-PGDS mRNA and protein were highly expressed in the interstitial tissue of adult testis. L-PGDS mRNA was first detected on d 30 after birth and exhibited an abundant signal in adult caput and cauda epididymis. L-PGDS immunostaining was first observed on d 30 after birth. There was a strong level of L-PGDS immunostaining in adult epididymis. Castrated male mice were treated with either vehicle or testosterone propionate following 3 d postcastration. L-PGDS expression steadily declined in a time-dependent fashion in control groups. No L-PGDS mRNA expression or immunostaining was detected in the controls for 12 d. When the castrated mice were treated with testosterone propionate for 5 or 12 d, L-PGDS expression was significantly increased in the whole epididymis. These data suggest that L-PGDS expression in mouse epididymis gradually declined in parallel to the declining concentration of endogenous androgen after castration and increased with the treatment of exogenous testosterone, indicating that L-PGDS expression in mouse epididymis was modulated by androgen levels. However, differential expression in different areas of the epididymis may also be influenced by factors derived from the testis.