降钙素对胚胎着床的影响机理

降钙素(calcitonin,CT)是甲状腺滤泡旁细胞分泌的一种含有32个氨基酸残基的肽类激素,是动物体内重要的调节钙磷代谢的内分泌因子。近年来的研究发现CT在胚胎着床过程中起着重要的作用。胚胎着床涉及到母体子宫和胚胎之间的复杂而精确的调控。在孕激素作用下,围着床期子宫内膜表达CT,CT与其膜受体结合后可激活腺苷酸环化酶(adenylate cyclase,AC)和磷脂酶(Cphospholipase C,PLC)等激酶的活性,促进细胞外Ca2 内流,从而促使子宫内膜和胚胎发生一系列的变化,有利于胚胎的植入。     

The effect of fludrocortisone on the uterine receptivity partially mediated by ERK1/2-mTOR pathway

Implantation of embryos needs endometrial receptivity. Mineralocorticoids is one of the causes influencing the implantation window. This study targeted to evaluation fludrocortisone different properties on endometrial receptivity. The objective of this study was to assess whether treatment with fludrocortisone could impact the expression of diverse genes and proteins that are involved in uterine receptivity in mice. In this study, 40 female adult BALB/c mice were used. The samples were allocated to four groups of ten. Control group (C) received: vehicle; fludrocortisone group (FCA): received 1.5 mg/kg fludrocortisone; PP242 group (PP242): received 30 mg/kg PP242; fludrocortisone+PP242 group (FCA+PP242): received fludrocortisone and PP242. Mice were killed on window implantation day after mating and confirmed pregnancy. The endometrial epithelium of mouse was collected to assess mRNA expression of leukemia inhibitory factor (LIF), mucin-1 (MUC1), heparin-binding epidermal growth factor (HB-EGF), (Msx.1), miRNA Let-7a, and miRNA 223-3p as well as protein expression of extracellular signal-regulated kinase 1/2 (ERK1/2), mammalian target of rapamycin (mTOR), and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) in the uterine using real-time PCR and western blot, respectively. In comparison with the control group, fludrocortisone administration upregulated the expression of LIF, HB-EGF, Msx.1, miRNA Let-7a, ERK1/2, and mTOR in the epithelial endometrium. The PP242-treated group demonstrated a significant rise in the expression of MUC1, miRNA 223-3p and a remarkable decline in ERK1/2 and p-4E-BP1 levels in comparison with the control group. Combination therapy of (FCA+PP242) resulted in a remarkable rise in LIF, Msx-1, HB-EGF, ERK1/2, and mTOR levels, in comparison with the PP242 group. Furthermore, combination therapy of (FCA+PP242) downregulated the expression of MUC1 in comparison with the PP242-treated group. According to the results, fludrocortisone affected uterine receptivity possibly by means of modulating the expression of genes involved in the uterine receptivity and activation of the ERK1/2-mTOR pathway.     

Development of a high-throughput assay for human proprotein convertase 5/6 for detecting uterine receptivity

Embryo implantation requires a healthy embryo and a receptive uterus. In women, the inner lining of the uterus, the endometrium, remains in a hostile state and becomes receptive for embryo implantation for only a short period during each menstrual cycle. Determining endometrial receptivity is vital in in vitro fertilization (IVF) treatment because the timing of embryo transfer needs to be synchronized with endometrial receptivity. We have previously demonstrated that proprotein convertase 5/6A (PC6) is highly expressed in the receptive endometrium and that PC6 is critical for receptivity establishment in women. Furthermore, endometrial PC6 is secreted into the uterine fluid, and levels correlate with receptivity status. Detection of PC6 in uterine fluids, therefore, would provide a nonsurgical assessment of endometrial receptivity. However, to date no assays are available for human PC6. In this study, we produced three PC6 monoclonal antibodies (mAbs) and developed a sandwich enzyme-linked immunosorbent assay (ELISA) for PC6 detection in human uterine fluids. The PC6 mAbs were confirmed to be highly specific to PC6, and the ELISA detected PC6 in human uterine fluids with a significantly higher level during the receptive phase. This newly established PC6 ELISA provides an important tool in the development of noninvasive strategies to detect endometrial receptivity in women.     

Neither protogynous nor obligatory out-crossed: pollination biology and breeding system of the European Red List Fritillaria meleagris L. (Liliaceae)

For 4 years we studied pollination biology and breeding system of the critically endangered, Red List plant Fritillaria meleagris L. (Liliaceae), in the larger of the two remaining populations of the plant in SE Poland. Our observations indicated that, contrary to literature data, the species is not dichogamous nor is it obligatorily out-crossing. Selfing, although rare in natural populations, results in fully developed seeds. Flowers are visited by several insect species, mostly social and solitary bees. In spite of extremely low visitation rates to this early spring-flowering plant, the species is not pollen limited. Although the largest pollen loads are transferred by solitary bees, the key pollinators are bumblebees (mostly the most common species, Bombus terrestris and B. lapidarius) due to their seasonal and floral constancy, and tolerance of bad weather conditions. The current decline of the studied population seems not to be related to the species' pollination or breeding systems but to plant habitat loss. It is suggested, however, that in smaller populations, the species' dependence on generally rare pollinators and largely out-crossed breeding system may accelerate local extinction.     

Reproductive biology in Anagyris foetida L. (Leguminosae), an autumn–winter flowering and ornithophilous Mediterranean shrub

As most plants of the Mediterranean region bloom in spring, there have been few studies of the reproductive biology of species with autumn–winter flowering. In this study, we investigate the breeding system of Anagyris foetida , one of the few shrubs that blooms at this time. The floral, phenological, and reproductive aspects of two populations of this Mediterranean legume from south-west Spain were studied via field and laboratory experiments. The variability of fruit and seeds was studied in another 12 Iberian populations with respect to certain meteorological parameters (temperature and rainfall). Anagyris foetida shows cauliflory, marked floral longevity, and adichogamy. The peak of flowering is in January–February. It is self-compatible, with no clear advantage of cross- over self-pollination, and with virtually no autonomous self-pollination. This is because the stigma, like some other legumes, prevents the germination of pollen if its surface is not ruptured by pollinators. The number of seeds per fruit under natural pollination was positively correlated with the total rainfall during the fruiting period (from January to May), and significantly influenced the percentage of fruit weight represented by the pericarp, in the sense that the smaller the number of viable seeds in the fruit, the greater the percentage of pericarp weight.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 519–532.     

子宫内膜接受性的建立和分子调控

胚泡着床是一个复杂的生理过程,依赖于胚泡发育和子宫内膜获得接受能力的同步进行.着床只发生在具有接受性的子宫内膜,而子宫内膜只在很短的时间内具有接受性.被称为"着床窗口".子宫内膜接受性的建立涉及子宫腔上皮的形态学改变,以及甾类激素和许多细胞因子复杂的调控作用.本文综述了子宫内膜接受性的建立及其分子调控.     

Activin βA subunit,follistatin and follistatin-like 3 are expressed in the endometrium of ovariectomized rats and regulated by estrogen replacement

Activin A is a growth factor expressed in the endometrium, where it modulates tissue remodeling and enhances decidualization. The effects of activin A are counteracted by two binding proteins, namely follistatin and follistatin-like 3 (FSTL3). We have evaluated the effects of estrogen and progestin on the endometrial expression of activin βA subunit, follistatin and FSTL3 in ovariectomized rats. Adult female Wistar rats (n = 21) were ovariectomized and received one week later a single dose of estradiol benzoate (1.5 mg/kg body weight, i.m. injection), either alone (n = 7) or associated with depot medroxyprogesterone acetate (3 mg/kg body weight, i.m. injection, n = 7), or oil vehicle (control group, n = 7). One week later, activin βA subunit mRNA levels had increased significantly in the uteri of rats treated with estradiol alone (7.4 fold increase over controls, P < 0.05) and to the same extent in rats receiving estradiol plus medroxyprogesterone (6.1 fold increase over controls, P < 0.05). This was accompanied by increase of βA subunit immunostaining in estradiol and estroprogestin treated rats, which was noted only in the surface endometrial epithelium. Follistatin mRNA expression, conversely, showed a significant decrease in the groups treated with estrogen alone and estrogen plus progestin (P < 0.05), and follistatin immunostaining in the glandular epithelium was weaker in estradiol and estroprogestin-treated rats compared to controls. FSTL3 expression was similar in the 3 groups. In conclusion, the expression of activin βA subunit increases and that of follistatin decreases following estrogen replacement in the endometrium of ovariectomized rats, and these effects are not further altered by the addition of progestin. Presented, in part, as a poster at the 55nd Annual Meeting of the Society for Gynecologic Investigation, San Diego, CA, March 2008.     

The roles and expression of HOXA/Hoxa10 gene: A prospective marker of mammalian female fertility?

This review addresses the influence of homebox A10/a10 (HOXA/Hoxa10) gene on reproductive tract anatomy and functional fertility in mammalian species, and discusses major endocrine and environmental regulators of HOXA/Hoxa10 expression. Female reproductive efficiency or success is a function of several factors including the ovulation and fertilization rate, and uterine receptivity. A family of HOX/Hox genes establishes the segmental identity of the reproductive tract during embryogenesis and retains its physiological plasticity in sexually mature animals and humans. In particular, the HOXA/Hoxa10 gene is an intrinsic component of implantation, decidualization, and immunomodulation in the adult uterus. It was, therefore, suggested that knowledge of HOXA/Hoxa10 regulation might be essential in navigating molecular mechanisms with the aim of enhancing female reproductive potential. However, a recent study in pigs revealed a lack of associations between endometrial HOXA10 expression and reproductive tract morphology, and very poor correlations with sows’ fertility metrics. Retinoic acid mainly regulates 3’ HOX/Hox paralogs but may also modify the expression of downstream HOX/Hox genes, including HOXA/Hoxa10. Sex steroids directly regulate HOXA/Hoxa10 expression. The vitamin D receptor pathway modulates HOXA/Hoxa10 expression in the adult reproductive tract. Lastly, endocrine disruptors such as diethylstilbestrol, methoxychlor, bisphenol A, and isoflavones were shown to alter HOXA/Hoxa10 expression, thus affecting reproductive competence of the female.     

N-glycosylation of uterine endometrium determines its receptivity

Glycosylation alters the molecular and functional features of glycoproteins, which is closely related with many physiological processes and diseases. During “window of implantation”, uterine endometrium transforms into a receptive status to accept the embryo, thereby establishing successful embryo implantation. In this article, we aimed at investigating the role of N-glycosylation, a major modification type of glycoproteins, in the process of endometrial receptivity establishment. Results found that human uterine endometrial tissues at mid-secretory phase exhibited Lectin PHA-E+L (recognizes the branched N-glycans) positive N-glycans as measured by the Lectin fluorescent staining analysis. By utilizing in vitro implantation model, we found that de-N-glycosylation of human endometrial Ishikawa and RL95-2 cells by tunicamycin (inhibitor of N-glycosylation) and peptide-N-glycosidase F (PNGase F) impaired their receptive ability to human trophoblastic JAR cells. Meanwhile, N-glycosylation of integrin αvβ3 and leukemia inhibitory factor receptor (LIFR) are found to play key roles in regulating the ECM-dependent FAK/Paxillin and LIF-induced STAT3 signaling pathways, respectively, thus affecting the receptive potentials of endometrial cells. Furthermore, in vivo experiments and primary mouse endometrial cells-embryos coculture model further verified that N-glycosylation of mouse endometrial cells contributed to the successful implantation. Our results provide new evidence to show that N-glycosylation of uterine endometrium is essential for maintaining the receptive functions, which gives a better understanding of the glycobiology of implantation.