Endometrium Of Animals Research Articles

Loss of HOXA10 causes endometrial hyperplasia progressing to endometrial cancer.

Endometrial cancer is the fourth most common malignancy in women and the precursor lesion is endometrial hyperplasia. HOXA10 is a transcription factor that plays key roles in endometrial functions such as the endowment of receptivity, embryo implantation, and trophoblast invasion. Herein, using testicular transgenesis, we developed transgenic mice that expressed a shRNA against HOXA10 and there was a nearly 70% reduction in the expression of HOXA10 in these animals. We observed that downregulation of HOXA10 led to the development of endometrial hyperplasia in the young animals (3 months), and as they aged (>1 year), most animals developed well-differentiated endometrial adenocarcinoma. In the endometrium of animals with reduced HOXA10, there was increased proliferation and elevated levels of ERα and ERβ. In parallel, there was increased expression of Wnt4 and β-Catenin, SOX9, and YAP1. We propose that chronic reduction in HOXA10 expression disrupts multiple pathways in the uterus that aids in the development of endometrial hyperplasia which progresses to endometrial cancer with age.

Immunity and Inflammation in the Uterus

Microbes often infect the uterus and particularly the endometrium of animals. Infections are most commonly associated with natural service, pregnancy and the post-partum period, leading to inflammation with the elaboration of cytokines, chemokines and prostaglandins. Clinical diseases such as metritis, endometritis and abortion are important causes of infertility. The adaptive immune response to infection has been characterized previously, so the present review aims to highlight the emerging role for innate immunity in the endometrium. The detection of microbes and the innate immune response depends on the detection of pathogen-associated molecular patterns by pattern recognition receptors. The main families of pattern recognition receptors are Toll-like receptors (TLRs), nucleotide oligomerization domain-like receptors, retinoic acid-inducible gene I-like receptors and C-type lectin receptors. These receptors are most often expressed by hematopoietic cells, but the epithelial and stromal cells of the endometrium also possess functional receptors. For example, endometrial cells express TLR4 for recognition of the lipopolysaccharide endotoxin of Gram-negative bacteria, leading to secretion of IL-6, IL-8 and prostaglandin E(2) . It is likely that the epithelial and stromal cells provide a first line of defence in the endometrium to alert hematopoietic cells to the presence of microbes within the uterus.

The Endometrial Response to Chorionic Gonadotropin Is Blunted in a Baboon Model of Endometriosis

Endometriosis-associated infertility has a multifactorial etiology. We tested the hypothesis that the endometrial response to the early embryonic signal, human chorionic gonadotropin (hCG), alters over time in a nonhuman primate model of endometriosis. Animals with experimental or spontaneous endometriosis were treated with hCG (30 IU/d), from d 6 after ovulation for 5 d, via an oviductal cannula. Microarray analysis of endometrial transcripts from baboons treated with hCG at 3 and 6 months of disease (n=6) identified 22 and 165 genes, respectively, whose levels differed more than 2-fold compared with disease-free (DF) animals treated with hCG (P<0.01). Quantitative RT-PCR confirmed abnormal responses of known hCG-regulated genes. APOA1, SFRP4, and PAPPA, which are normally down-regulated by hCG were up-regulated by hCG in animals with endometriosis. In contrast, the ability of hCG to induce SERPINA3 was lost. Immunohistochemistry demonstrated dysregulation of C3 and superoxide dismutase 2 proteins. We demonstrate that this abnormal response to hCG persists for up to 15 months after disease induction and that the nature of the abnormal response changes as the disease progresses. Immunohistochemistry showed that this aberrant gene expression was not a consequence of altered LH/choriogonadotropin receptor distribution in the endometrium of animals with endometriosis. We have shown that endometriosis induces complex changes in the response of eutopic endometrium to hCG, which may prevent the acquisition of the full endometrial molecular repertoire necessary for decidualization and tolerance of the fetal allograft. This may in part explain endometriosis-associated implantation failure.

The eutopic endometrial response to chorionic gonadotrophin is abnormal in a baboon model of endometriosis: a possible explanation for endometriosis associated implantation failure

OBJECTIVE: To test the hypothesis that the endometrial response to Chorionic Gonadotrophin (CG) the major early, embryo derived signal, is altered by the presence of endometriosis. DESIGN: We assessed endometrial morphology, protein and gene expression changes occurring after in vivo intra-oviductal CG treatment of baboons with endometriosis. MATERIALS AND METHODS: Endometriosis was experimentally induced in female baboons (n=5) by intraperitoneal inoculation with menstrual endometrium. Three and six months following disease induction, human CG (hCG; 30IU/day) was infused into the oviduct via a subcutaneous osmotic mini-pump and polyurethane cannula. HCG infusion began on day 6 post ovulation (PO). Endometrial tissue was subsequently harvested by endometriectomy between days 9 to 11 PO, corresponding to the approximate time of implantation in the baboon. Control endometria were similarly harvested from disease free animals (n=6). Total RNA from each animal was hybridized to HumanRef-6 v3.0 Expression BeadChips (Illumina) containing 23,000 unique genes. Microarray data analyses were performed using BRB Array Tools. Verification of microarray data was performed using real time (RT) PCR; protein abundance changes were assayed by immunohistochemistry. All experimental procedures were approved by the Animal Care Committee of the University of Illinois, Chicago. RESULTS: Assessment of an early morphological response of baboon endometrium to hCG, the development of an epithelial plaque, revealed that the endometrium of all control animals was stimulated by hCG. However, an epithelial plaque was only elicited by hCG in two of five animals with endometriosis. Microarray analysis of endometria from baboons three and six months following induction of disease identified 22 and 116 genes, respectively, whose transcript levels differed more than 2-fold from those of control endometria (p<0.05). Several of these genes were previously shown to be regulated by hCG in disease free baboons. RT PCR analysis confirmed aberrant levels of LIF, complement factor C3, sFRP4 and SERPA3 in endometria of baboons with endometriosis. Immunohistochemical analysis revealed that this aberrant gene expression profile was not a result of altered CG receptor distribution in the endometrium of animals with endometriosis. CONCLUSIONS: An altered response to CG may prevent the acquisition of the full endometrial molecular repertoire necessary for implantation and may in part explain the implantation failure associated with endometriosis.

The Secretion of a Uterine Specific, Purple Phosphatase by Cultured Explants of Porcine Endometrium Dependency upon the State of Pregnancy of the Donor Animal1

Explants of endometrium from the porcine uterus secrete labeled proteins into the growth medium when incubated in vitro in modified Eagle’s MEM4 containing radioactive L-leucine. Tissue from 60 day pregnant animals secrete about 30 times as much radioactive material into the medium in 24 h as explants taken from nonpregnant animals on Day 3 of the estrous cycle. The secretions by tissue from pregnant animals were also qualitatively distinct and contained appreciable quantities of 2 basic proteins, lysozyme and a uterine-specific phosphatase. The latter was identical to an iron-containing purple protein previously purified either from uterine secretions of progesterone treated, nonpregnant animals or from allantoic fluid. This protein is believed to be involved in iron transport from mother to fetus. Explants from the endometrium of animals on Days 30, 45, 60, 75, 90 and 105 of pregnancy showed considerable differences in their capacities to produce the purple protein. Production was maximal by Day 60 tissue (2 mg/g tissue/24 h), but very low in tissue from late pregnancy (Day 105), an observation which may have considerable implication with regard to dietary iron supplementation of the pregnant sow. Neither the presence of progesterone nor estradiol-17a in the incubation medium altered the quantity or quality of the proteins produced by the explants during the 24 h incubation. We conclude that it is the hormonal environment of the endometrium at the time of surgery which primarily governs the quantity and quality of the proteins by short term cultured explants.

Translation of the mRNA for rabbit uteroglobin in cell-free systems. Evidence for a precursor protein.

Uteroglobin, an hormonally induced protein composed of two similar subunits, represents around 50% of the proteins synthesized and secreted into the uterine lumen of rabbits treated sequentially with estradiol and progesterone. The endometrium of these animals was used as a source for the isolation of the mRNA for uteroglobin. Poly(A)-rich RNA, extracted from purified polysomes with phenol chloroform and isolated on oligo(dT)-cellulose columns, contains one fourth of the total protein coding activity of the endometrium. Between 20--25% of the polypeptides synthesized by this RNA in cell-free systems derived from Krebs II ascites cells or wheat germs react with a monospecific antiserum prepared in guinea pigs against uteroglobin. The material bound to the antibody was identified as a precursor of uteroglobin according to the following criteria. 1. The product synthesized in vitro can be displaced from the complex with the specific immunoglobulin by purified uteroglobin. 2. Analysis of the immunoprecipitate on polyacrylamide gels containing urea and dodecylsulfate demonstrate the existence of a single labelled polypeptide with an apparent molecular weight larger than the uteroglobin subunits. 3. The tryptic digest of this polypeptide, labelled in vitro with [3H]lysine, shares seven peptides with mature uteroglobin labelled with the same amino acid in perfused uteri, and exhibits and additional peptide not present in uteroglobin. 4. Injection of the same mRNA preparation into Xenopus oocytes results in the production of uteroglobin. The endometrium of intact animals treated with estradiol alone also contains the same mRNA bound to polysomes but in a smaller proportion, indicating that the progesterone-induced synthesis of uteroglobin is accompanied by an accumulation of the specific mRNA in the polysomes.