The matrix metalloproteinase system: changes, regulation, and impact throughout the ovarian and uterine reproductive cycle

Neutrophil depletion retards endometrial repair in a mouse model

The contribution of the high abundance of inflammatory cells present in the human endometrium prior to and during menstruation is unknown with respect to endometrial repair and/or menstruation. In this study, the presence and localisation of markers for key inflammatory cells have been examined in a mouse model of endometrial breakdown and repair and the functional contribution of neutrophils has been determined. In the model, decidualisation is artificially induced and progesterone support withdrawn; the endometrial tissue progressively breaks down by 24 h after progesterone withdrawal and, by 48 h, has usually undergone complete repair. Neutrophils have been identified in low abundance in decidual tissue, rise in number during breakdown and are most abundant during early repair. Macrophages are barely detectable during breakdown or repair in this model, whereas uterine natural killer cells are found only in intact decidua. The functional contribution of neutrophils to endometrial breakdown and repair has been assessed via neutrophil depletion by using the antibody RB6-8C5. This antibody significantly depletes neutrophils from the circulation and tissue, affects endometrial breakdown and markedly delays endometrial repair. This study has therefore demonstrated that neutrophils are the most abundant leucocyte in this model and that they play an important functional role in the processes of endometrial breakdown and repair.

Regulation of A Disintegrin And Metalloproteinase with ThromboSpondin repeats-1 expression in human endometrial stromal cells by gonadal steroids involves progestins, androgens, and estrogens

CONTEXT

Gonadal steroids are key regulators of the extracellular matrix remodeling events that occur in the human endometrium during each menstrual cycle. The spatiotemporal expression of A Disintegrin And Metalloproteinase with ThromboSpondin repeats (ADAMTS)-1 in human endometrial stroma in vivo suggests that this novel metalloproteinase may contribute to this tightly regulated developmental process.

OBJECTIVE

The objective of the study was to determine whether progesterone (P4), 17beta-estradiol (E2), or the nonaromatizable androgen dihydrotestosterone (DHT), alone or in combination, is capable of regulating ADAMTS-1 mRNA and protein levels in human endometrial stromal cells in a concentration- and time-dependent manner.

DESIGN

A real-time quantitative PCR strategy and Western blotting were used to examine ADAMTS-1 mRNA and protein expression levels in primary cultures of human endometrial stromal cells.

RESULTS

P4 and DHT but not E2 increased the levels of the ADAMTS-1 mRNA transcript and protein species (110 kDa) present in endometrial stromal cells in vitro in a concentration- and time-dependent manner. A combination of P4 and DHT resulted in an additional increase in stromal ADAMTS-1 expression, whereas E2 attenuated the regulatory effects of P4 and DHT in a concentration-dependent manner. The antisteroidal compounds, mifepristone (RU486) and hydroxyflutamide, were also found to inhibit specifically the P4- and DHT-mediated increase in ADAMTS-1 mRNA and protein expression levels in these primary cell cultures in a concentration-dependent manner, respectively.

CONCLUSIONS

These studies demonstrate that progestins, androgens, and estrogens, alone and in combination, have distinct regulatory effects on ADAMTS-1 mRNA and protein expression levels in human endometrial stromal cells in vitro.

Requirement for ADAMTS-1 in extracellular matrix remodeling during ovarian folliculogenesis and lymphangiogenesis

Murine ovarian folliculogenesis commences after birth involving oocyte growth, somatic cell differentiation and structural remodeling of follicle stromal boundaries. The extracellular metalloproteinase ADAMTS-1 has activity against proteoglycans and collagen and is produced by the granulosa cells of ovarian follicles. Mice with ADAMTS-1 gene disruption are subfertile due to an unknown mechanism resulting in severely reduced ovulation. Here we show that ADAMTS-1 is necessary for structural remodeling during ovarian follicle growth. A significant reduction in the number of healthy growing follicles and corresponding follicle dysmorphogenesis commencing at the stage of antrum formation was identified in ADAMTS-1-/- ovaries. Morphological analysis and immunostaining of basement membrane components identified stages of follicle dysgenesis from focal disruption in ECM integrity to complete loss of follicular structures. Cells expressing the thecal marker Cyp-17 were lost from dysgenic regions, while oocytes and dispersed cells expressing the granulosa cell marker anti-mullerian hormone persisted in ovarian stroma. Furthermore, we found that the ovarian lymphatic system develops coincidentally with follicular development in early postnatal life but is severely delayed in ADAMTS-1-/- ovaries. These novel roles for ADAMTS-1 in structural maintenance of follicular basement membranes and lymphangiogenesis provide new mechanistic understanding of folliculogenesis, fertility and disease.

Gelatinases, endonuclease and Vascular Endothelial Growth Factor during development and regression of swine luteal tissue

BACKGROUND

The development and regression of corpus luteum (CL) is characterized by an intense angiogenesis and angioregression accompanied by luteal tissue and extracellular matrix (ECM) remodelling. Vascular Endothelial Growth Factor (VEGF) is the main regulator of angiogenesis, promoting endothelial cell mitosis and differentiation. After the formation of neovascular tubes, the remodelling of ECM is essential for the correct development of CL, particularly by the action of specific class of proteolytic enzymes known as matrix metalloproteinases (MMPs). During luteal regression, characterized by an apoptotic process and successively by an intense ECM and luteal degradation, the activation of Ca++/Mg++-dependent endonucleases and MMPs activity are required. The levels of expression and activity of VEGF, MMP-2 and -9, and Ca++/Mg++-dependent endonucleases throughout the oestrous cycle and at pregnancy were analyzed.

RESULTS

Different patterns of VEGF, MMPs and Ca++/Mg++-dependent endonuclease were observed in swine CL during different luteal phases and at pregnancy. Immediately after ovulation, the highest levels of VEGF mRNA/protein and MMP-9 activity were detected. On days 5-14 after ovulation, VEGF expression and MMP-2 and -9 activities are at basal levels, while Ca++/Mg++-dependent endonuclease levels increased significantly in relation to day 1. Only at luteolysis (day 17), Ca++/Mg++-dependent endonuclease and MMP-2 spontaneous activity increased significantly. At pregnancy, high levels of MMP-9 and VEGF were observed.

CONCLUSION

Our findings, obtained from a precisely controlled in vivo model of CL development and regression, allow us to determine relationships among VEGF, MMPs and endonucleases during angiogenesis and angioregression. Thus, CL provides a very interesting model for studying factors involved in vascular remodelling.

Coregulation of vascular tube stabilization by endothelial cell TIMP-2 and pericyte TIMP-3

The endothelial cell (EC)–derived tissue inhibitor of metalloproteinase-2 (TIMP-2) and pericyte-derived TIMP-3 are shown to coregulate human capillary tube stabilization following EC–pericyte interactions through a combined ability to block EC tube morphogenesis and regression in three-dimensional collagen matrices. EC–pericyte interactions strongly induce TIMP-3 expression by pericytes, whereas ECs produce TIMP-2 in EC–pericyte cocultures. Using small interfering RNA technology, the suppression of EC TIMP-2 and pericyte TIMP-3 expression leads to capillary tube regression in these cocultures in a matrix metalloproteinase-1 (MMP-1)–, MMP-10–, and ADAM-15 (a disintegrin and metalloproteinase-15)–dependent manner. Furthermore, we show that EC tube morphogenesis (lumen formation and invasion) is primarily controlled by the TIMP-2 and -3 target membrane type (MT) 1 MMP. Additional targets of these inhibitors include MT2-MMP and ADAM-15, which also regulate EC invasion. Mutagenesis experiments reveal that TIMP-3 requires its proteinase inhibitory function to induce tube stabilization. Overall, these data reveal a novel role for both TIMP-2 and -3 in the pericyte-induced stabilization of newly formed vascular networks that are predisposed to undergo regression and reveal specific molecular targets of the inhibitors regulating these events.

Expression of interleukin-18 receptor mRNA in the mouse endometrium

Interleukin-18 (IL-18) is a proinflammatory cytokine involved in chronic inflammation, autoimmune diseases, and a variety of cancers, and is expressed in mouse uteri. Our previous study suggested that IL-18 acts as a paracrine factor, regulating endometrial function. To elucidate the physiological roles of IL-18 in the mouse endometrium, the expression of the IL-18 receptor (IL-18R) alpha subunit was analyzed. IL-18Ralpha mRNA was expressed in several mouse organs in addition to the endometrium. In situ hybridization analysis using a biotin-labeled mouse IL-18Ralpha riboprobe demonstrated that IL-18Ralpha mRNA expression was detected in glandular epithelial cells, stromal cells around uterine glands, and myometrial cells in the mouse uterus, suggesting that these cells are targets for IL-18. The uterine IL-18Ralpha mRNA expression level changed with the estrous cycle. The uterine IL-18Ralpha mRNA levels of estrous mice were higher than those of diestrous mice. In addition, the IL-18Ralpha mRNA levels in uteri at 3 and 14 days after ovariectomy were higher than those at diestrus and decreased following treatment with estradiol-17beta or progesterone. These findings suggest that IL-18Ralpha gene expression is regulated by estrogen and progesterone and that the uterine IL-18 system is involved in the regulation of uterine functions in a paracrine manner.

Nuclear factor-kappab (NF-kappaB): an unsuspected major culprit in the pathogenesis of endometriosis that is still at large?

Endometriosis, defined as the ectopic presence of endometrial glandular and stromal cells outside the uterine cavity, is a common benign gynecological disorder with an enigmatic pathogenesis. Many genes and gene products have been reported to be altered in endometriosis, yet some of them may not be major culprits but merely unwitting accomplices or even innocent bystanders. Therefore, the identification and apprehension of major culprits in the pathogenesis of endometriosis are crucial to the understanding of the pathogenesis and would help to develop better therapeutics for endometriosis. Although so far NF-kappaB only has left few traces of incriminating fingerprints, several lines of investigation suggest that NF-kappaB, a pivotal pro-inflammatory transcription factor, could promote and maintain endometriosis. Various inflammatory agents, growth factors, and oxidative stress activate NF-kappaB. NF-kappaB proteins themselves and proteins regulated by them have been linked to cellular transformation, proliferation, apoptosis, angiogenesis, and invasion. Interestingly, all existing and nearly all investigational medications for endometriosis appear to act through suppression of NF-kappaB activation. In endometriotic cells, NF-kappaB appears to be constitutively activated, and suppression of NF-kappaB activity by NF-kappaB inhibitors or proteasome inhibitors suppresses proliferation in vitro. Viewing NF-kappaB as a major culprit, an autoregulatory loop model can be postulated, which is consistent with existing data and, more importantly, can explain several puzzling phenomena that are otherwise difficult to interpret based on prevailing theories. This view has immediate and important implications for novel ways to treat endometriosis. Further research is warranted to precisely delineate the roles of NF-kappaB in the pathogenesis of endometriosis and to indict and convict its aiders and abettors.

Developmental exposure of mice to TCDD elicits a similar uterine phenotype in adult animals as observed in women with endometriosis

Whether environmental toxicants impact an individual woman's risk for developing endometriosis remains uncertain. Although the growth of endometrial glands and stroma at extra-uterine sites is associated with retrograde menstruation, our studies suggest that reduced responsiveness to progesterone may increase the invasive capacity of endometrial tissue in women with endometriosis. Interestingly, our recent studies using isolated human endometrial cells in short-term culture suggest that experimental exposure to the environmental contaminant 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD) can alter the expression of progesterone receptor isotypes. Compared to adult exposure, toxicant exposure during development can exert a significantly greater biological impact, potentially affecting the incidence of endometriosis in adults. To address this possibility, we exposed mice to TCDD at critical developmental time points and subsequently examined uterine progesterone receptor expression and steroid responsive transforming growth factor-beta2 expression in adult animals. We find that the uterine phenotype of toxicant-exposed mice is markedly similarly to the endometrial phenotype of women with endometriosis.

Expression of matrix metalloproteinase-26 and tissue inhibitors of metalloproteinase-3 and -4 in normal ovary and ovarian carcinoma

The objective of this study was to determine the spatial expression of matrix metalloproteinases (MMPs) and their physiologic inhibitors, the tissue inhibitor of MMP (TIMP)-3 and TIMP-4, in ovarian carcinoma compared to normal ovaries. Immunohistochemistry was carried out in this study. Tissue sections prepared from normal ovarian tissues from throughout the menstrual cycle (N = 20) and ovarian carcinomas (N = 45) characterized as stage I (N = 5), stage III/IV (N = 40) were immunostained using polyclonal antibodies to the latent and the active form of MMP-26, TIMP-3, and a monoclonal antibody to TIMP-4. Immunoreactive MMP-26, TIMP-3, and TIMP-4 were detected in all the ovarian cell types in normal and tumor tissues. In normal ovarian tissues, theca externa and luteal cells immunostained with high intensity for MMP-26 and TIMPs while theca/granulosa cell staining intensity increased as lutenization progressed. There was low immunostaining of the ovarian stromal and surface epithelial cells for MMP-26, with moderate staining for TIMPs. In the carcinoma specimens, cancer cells and vascular endothelial cells displayed the highest staining intensity compared to adjacent nontumor areas. The immunostaining intensity of MMP-26 and TIMP-3 increased with stage of tumor with the invading tumor cells displaying the strongest immunostaining. MMP-26, TIMP-3, and TIMP-4 are expressed in normal ovarian as well as ovarian tumors with elevated expression in the invasive tumor cells suggesting a potential role for MMP-26 in normal ovary and ovarian cancer biologic function.

Implication of ADAM-8, -9, -10, -12, -15, -17, and ADAMTS-1 in implantational remodeling of a mouse uterus

In the present study, whether the ADAM-8, -9, -10, -12, -15, -17, and ADAMTS-1 proteins might play a role in mouse uterus during periimplantation period was investigated. Immunoblotting analyses demonstrated that all ADAM proteins consistently appeared throughout days 1 to 8 of pregnancy but with a variation depending on the species of ADAM gene, the progression of pregnancy, and the site of the uterus. Immunohistochemical analyses indicated that ADAM proteins were localized in the luminal or glandular epithelial layers with a varying intensity depending on the species of ADAM and the progression of pregnancy. Particularly ADAM-8, -12, and -15, were predominantly located in the implantation site of the uterine tissues, whereas little or no protein was localized in the interimplantation site. Based upon these observations, it is suggested that the ADAMs might play an important role in the remodeling of the mouse uterus during the periimplantation period.

Lasofoxifene: a third-generation selective estrogen receptor modulator for the prevention and treatment of osteoporosis

This article reviews lasofoxifene, a new-generation selective estrogen receptor modulator (SERM) that is currently in Phase III development for the prevention and treatment of osteoporosis in postmenopausal women. This compound selectively binds to both of the estrogen receptors with a high affinity and a median inhibitory concentration that is similar to that seen with estradiol and > or = 10-fold higher than those reported for other SERMs (raloxifene and tamoxifen). Lasofoxifene has a remarkably improved oral bioavailability with respect to other SERMs due to increased resistance to intestinal wall glucuronidation. In both preclinical and short-term studies, the compound showed a favourable safety profile and demonstrated a proven efficacy in preventing bone loss and lowering cholesterol levels. Dose modelling from Phase II studies allowed the selection of lasofoxifene 0.25 mg/day as the lowest fully effective dose.

Expression of an extracellular matrix metalloproteinase inducer (basigin) in the human ovary and ovarian endometriosis

OBJECTIVE

To characterize the expression of basigin in ovarian endometriotic tissue, normal ovary, and endometrium during the menstrual cycle.

DESIGN

Controlled, retrospective study for evaluation of basigin expression in archived specimens.

SETTING

Academic research environment: University of Kentucky College of Medicine.

PATIENT(S)

Archived surgical specimens selected by retrospective chart review of age-matched (39 +/- 2.5 years) patients with and without ovarian endometriosis.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Expression localization of basigin mRNA and protein.

RESULT(S)

Basigin (mRNA and protein) was localized to granulosa cells (follicles of all stages), the ovarian surface epithelium, and granulosa and theca lutein of corpora lutea. Differential patterns of expression were apparent among samples of eutopic endometrium collected during the proliferative and secretory stages. In endometriotic lesions on the ovary, basigin was detected in the glandular epithelia and stroma of proliferative and secretory phase samples, but patterns of expression were unsynchronized with those of the eutopic endometrium from the same patient.

CONCLUSION(S)

The current data demonstrate unique expression patterns of basigin in the human ovary and endometriotic tissue, thereby supporting a possible role in normal ovarian function and in the dysregulation of proteolytic matrix metalloproteinases in endometriosis.

The identification of novel ovarian proteases through the use of genomic and bioinformatic methodologies

Proteolytic activities are essential for follicular growth, ovulation, as well as for luteal formation and regression. Using suppression subtractive hybridization (SSH), a novel mouse ovary-selective gene (termed protease serine 35, Prss35) was identified. Analysis of the mouse genome database using the Prss35 sequence led to the identification of a homologous protease (protease serine 23, Prss23). PRSS35 possesses general features that are characteristic of serine (Ser) proteases, but is unique in that the canonical Ser that defines this enzyme family is replaced by a threonine (Thr). In contrast, PRSS23 possesses the standard catalytic Ser typical for this family of proteases. As determined by real-time polymerase chain reaction (PCR), the Prss35 mRNA levels increased around the time of ovulation and remained elevated in the developing corpus luteum. Steroid ablation/replacement studies demonstrated progesterone-dependent regulation of Prss35 gene expression prior to follicle rupture. Prss35 gene expression was localized to the theca cells of pre-antral follicles, the theca and granulosa cells of pre-ovulatory and ovulatory follicles, as well as to the developing corpus luteum. In contrast, Prss23 mRNA levels decreased transiently after ovulation induction and again in the postovulatory period. Prss23 gene expression was noted primarily in the granulosa cells of the secondary/early antral follicles. PRSS35 and PRSS23 orthologs in the rat, human, rhesus macaque, chimpanzee, cattle, dog, and chicken were identified and found to be highly homologous to one another (75-99% homology). Collectively, these results suggest that the PRSS35 and PRSS23 genes have been conserved as critical ovarian proteases throughout the course of vertebrate evolution.

The interplay of cell-cell and cell-matrix interactions in the invasive properties of brain tumors

Impairment of tissue cohesion and the reorganization of the extracellular matrix are crucial events during the progression toward invasive cell phenotype. We studied the in vitro invasion patterns of nine brain tumor cell lines in three-dimensional collagen gels. Cell-cell and cell-matrix interactions were quantified and correlated with the expression level of specific molecules: N-cadherin, matrix metalloproteinases, and their inhibitor. Pattern evolution was studied as a function of time and collagen concentration. Cells with low metalloproteinase expression or high tissue cohesion showed limited invasive potential. Higher metalloproteinase expression and intermediate tissue cohesion resulted in configurations with hypercellular zones surrounding regions mostly devoid of cells and with digested collagen, akin to pseudopalisades in surgically removed malignant astrocytoma specimens. In physical terms, these configurations arise as the result of competition between cell-cell and cell-matrix interactions. Our findings suggest specific ways to characterize, control, or engineer cell migratory patterns and hint at the importance of the interplay between biophysical and biomolecular factors in the characterization of invasive cell behavior and, more generally, in epithelial-mesenchymal transitions.

Progesterone and interferon-tau regulate cystatin C in the endometrium

Cystatin C (CST3) is a secreted inhibitor of lysosomal cysteine proteases cathepsins B (CTSB) and CTSL, which are abundant in the ovine endometrium and conceptus. In mice, cathepsins and cystatins play important roles in implantation and placentation. This study determined effects of the estrous cycle, pregnancy, progesterone (P4), and interferon-tau (IFNT) on CST3 in the ovine uterus. In cyclic ewes, CST3 mRNA was low on d 10, increased about 12-fold by d 12, and declined thereafter. In early pregnant ewes, CST3 mRNA was low on d 10 and increased about 130-fold from d 10 to d 20. CST3 mRNA and protein were abundant in the endometrial luminal epithelium (LE) and glandular epithelium and also in conceptus trophectoderm. In uterine flushes from pregnant ewes, CST3 protein was not detected on d 10 but was abundant on d 12, 14, and 16. In another study, treatment of ovariectomized, cyclic ewes with P4 induced a 14-fold increase in endometrial CST3 mRNA, and IFNT stimulated an additional 2-fold increase in CST3 mRNA in P4-treated ewes but not in ewes treated with P4 and the antiprogestin ZK 136,317. CST3 mRNA and protein were abundant in the endometrial luminal epithelium and superficial glandular epithelium of P4-treated ewes but were very low or not detectable in endometria of P4- and ZK-treated ewes. These results indicate that CST3 is a novel P4-induced and IFNT-stimulated gene expressed only in the epithelial cells of the ovine endometrium and implicate CST3 in regulation of uterine cathepsin activity during conceptus implantation.

Targeted retroviral vectors displaying a cleavage site-engineered hemagglutinin (HA) through HA-protease interactions

We report here a targeting method that exploits the expression pattern of cell surface proteases to induce gene delivery to specific tissues. We describe retroviral vectors harboring modified surface glycoproteins derived from an avian influenza virus hemagglutinin (HA) for which the cell entry properties, dependent on HA cleavage by producer cells, were conditionally blocked at a postbinding step by insertion of matrix metalloproteinase (MMP) substrates. We demonstrate that such vectors induce gene transfer, both in vitro and in mice harboring human tumor xenografts, only through contact with target cells expressing MMPs that cleave the substrate introduced into the recombinant HA. This selective gene transfer in MMP-rich cells was specifically inhibited by 1,10-phenanthroline, a broad-range MMP inhibitor. Importantly, such MMP-activatable vectors selectively transduced MMP-rich cells in heterogeneous populations containing MMP-rich and MMP-poor cells. These vectors will allow useful gene transfer applications into target cells exhibiting specific protease activities.

Localization and temporal regulation of tissue inhibitor of metalloproteinases-4 in mouse ovary

Tissue inhibitors of metalloproteinases (TIMPs) are potential regulators of tissue remodeling in the ovary. The aim of the present study was to examine the localization and temporal regulation of TIMP-4 protein in the mouse ovary. An induced superovulation model (eCG/hCG) was employed in immature mice to evaluate TIMP-4 protein expression profiles in ovaries collected during the follicular phase, the pre ovulatory period, and the luteal lifespan. Immunofluorescence results indicated that TIMP-4 protein was localized to theca of both antral and preovulatory follicles and adjacent ovarian stroma. After the initiation of luteinization with hCG, TIMP-4 was observed within the luteinizing granulosa cells and persisted throughout the lifespan of the corpus luteum. In the cycling ovary, TIMP-4 signaling localized to corpus luteum from previous estrous cycles, the theca of preovulatory follicles, and appeared to be lower in newly forming corpus luteum. Western analysis further showed that the levels of TIMP-4 increased significantly during the luteinization process of granulosa cells, but no significant change was found among all corpus luteum stages. A putative regulatory mechanism of TIMP-4 expression was identified utilizing an in vitro model. Treatment of cultured granulosa cells with hCG significantly augmented TIMP-4 protein expression levels. Together our data indicate that the luteinization process of granulosa cells is associated with up-regulation of TIMP-4 and that TIMP-4 might play an essential role in maintenance of the luteal function during the whole lifespan of corpus luteum.

Matrix metalloproteinases in development and disease

Matrix metalloproteinases (MMPs) are key modulators of many biological processes during pathophysiological events, such as skeletal formation, angiogenesis, cellular migration, inflammation, wound healing, coagulation, lung and cardiovascular diseases, arthritis, and cancer. Twenty-four members of the MMP family have been identified in humans, degrading many components of the extracellular matrix, cellular receptors, and cytokines. This review describes the molecular structure, activation and inhibition, and substrate specificity of MMPs, and their biological function in development and disease.

Induction of antitumor immunity through xenoplacental immunization

Historically cancer vaccines have yielded suboptimal clinical results. We have developed a novel strategy for eliciting antitumor immunity based upon homology between neoplastic tissue and the developing placenta. Placenta formation shares several key processes with neoplasia, namely: angiogenesis, activation of matrix metalloproteases, and active suppression of immune function. Immune responses against xenoantigens are well known to break self-tolerance. Utilizing xenogeneic placental protein extracts as a vaccine, we have successfully induced anti-tumor immunity against B16 melanoma in C57/BL6 mice, whereas control xenogeneic extracts and B16 tumor extracts where ineffective, or actually promoted tumor growth, respectively. Furthermore, dendritic cells were able to prime tumor immunity when pulsed with the placental xenoantigens. While vaccination-induced tumor regression was abolished in mice depleted of CD4 T cells, both CD4 and CD8 cells were needed to adoptively transfer immunity to naïve mice. Supporting the role of CD8 cells in controlling tumor growth are findings that only freshly isolated CD8 cells from immunized mice were capable of inducing tumor cell caspases-3 activation ex vivo. These data suggest feasibility of using xenogeneic placental preparations as a multivalent vaccine potently targeting not just tumor antigens, but processes that are essential for tumor maintenance of malignant potential.

Association of E-cadherin, matrix metalloproteinases, and tissue inhibitors of metalloproteinases with the progression and metastasis of hepatocellular carcinoma

Molecular markers can provide additional information to traditional histomorphological evaluation for the assessment of tumor progression and predicting the likelihood of invasion and metastasis in various types of malignancies. We studied the association of E-cadherin, matrix metalloproteinases (MMPs), and tissue inhibitors of metalloproteinase with the progression and metastasis of hepatocellular carcinoma. Tissue microarray including six normal livers, 14 cirrhotic livers, 39 macroregenerative nodules, 16 dysplastic nodules, 22 grade I hepatocellular carcinomas, 43 grade II hepatocellular carcinomas, seven grade III hepatocellular carcinomas, and 10 metastatic hepatocellular carcinomas were stained immunohistochemically with antibodies against MMPs -1, -2, -3, -7, -9, tissue inhibitors of metalloproteinase-1, -2, -3, and E-cadherin. The intensities of staining were scored manually by two pathologists and verified by the Chromavision Automated Cellular Imaging System. Compared with normal liver, cirrhotic liver had significantly lower E-cadherin and tissue inhibitors of metalloproteinase-1 but higher MMP-1 and -7, which suggest a more favorable environment for tumor invasion and metastasis. Grade I and grade II hepatocellular carcinomas demonstrated high E-cadherin and decreased MMP-3 and -9, which may explain the rarity of extrahepatic metastasis in low-grade hepatocellular carcinomas despite the high circulatory volume of the liver. The histological progression from dysplastic nodule to well-differentiated hepatocellular carcinoma and to less differentiated tumors was associated with a gradual decrease in tissue expression of E-cadherin, tissue inhibitors of metalloproteinase-2 and -3. Metastatic hepatocellular carcinomas showed significantly lower level of tissue inhibitors of metalloproteinase-1, -2, -3 but higher level of MMP-7. These data suggest that tissue expression of E-cadherin, certain MMPs, and tissue inhibitors of metalloproteinases could be useful markers to predict the progression and metastasis of hepatocellular carcinoma.

Medical management of endometriosis

Current approved medical therapies for endometriosis rely on drugs that suppress ovarian steroids and induce a hypoestrogenic state, which determines the atrophy of the ectopic endometrium. Gonadotropin-releasing hormone analogs such as danazol, progestogens and estrogen-progestin combinations have all proven effective in relieving pain and reducing the extent of endometriotic implants. However, symptoms often recur after discontinuation of therapy and hypoestrogenism-related side effects limit the long-term use of most medications. Recently, knowledge of the pathogenesis of endometriosis, particularly at the molecular level, has grown substantially, providing a rational basis for the development of new drugs with precise targets that may be safely administered over the long term.

Effect of intrafollicular indomethacin injection on gonadotropin surge-induced expression of select extracellular matrix degrading enzymes and their inhibitors in bovine preovulatory follicles

A growing body of evidence supports an obligatory role for intrafollicular prostanoids in the mechanism of ovulation. However, the prostanoid-dependent mediators of the follicular extracellular matrix degradation required for ovulation are unknown. The objectives of this study were to determine the cellular compartment(s) in which the gonadotropin surge-induced regulation of select extracellular matrix degrading enzymes and their cognate inhibitors occurs in bovine preovulatory follicles, and to test whether such regulation is blocked by intrafollicular administration of the prostanoid synthesis and ovulation inhibitor, indomethacin (INDO). Follicular fluid prostaglandin E2 concentrations were elevated in diluent-treated follicles before ovulation (24 h after GnRH injection), but the increase was blocked in INDO-treated follicles. Real-time PCR analysis revealed the specific follicular cell types where gonadotropin surge-induced increases in mRNA abundance for members of the matrix metalloproteinase/tissue inhibitor of metalloproteinase and plasminogen activator families occurred. INDO treatment increased thecal cell mRNA for tissue inhibitor of metalloproteinase-4 and its protein abundance in the apex of preovulatory follicles before ovulation, but suppressed granulosal cell mRNA and activity for tissue plasminogen activator in follicular fluid and the follicle apex. Plasmin activity was also suppressed in the follicular fluid of INDO-treated follicles. Effects of INDO injection on select matrix metalloproteinases were not observed. The results suggest that gonadotropin surge-induced regulation of tissue inhibitor of metalloproteinase-4 and tissue plasminogen activator may be prostanoid dependent, and support a potential role for increased tissue plasminogen activator expression and decreased tissue inhibitor of metalloproteinase-4 expression in the mechanism of ovulation.

Serum activity of matrix metalloproteinases-2 and-9

Matrix metalloproteinases belong to the key effectors of tissue remodeling in health and disease. Matrix metalloproteinases -2 and -9, the most prevalent representatives of this family, are expressed in the endometrium. Chronic endometritis concomitant with sterility and spontaneous abortions is associated with decreased content of matrix metalloproteinases in the endometrium. Chronic endometritis combined with sterility correlates with decreased serum activities of matrix metalloproteinases -2 and -9, which returns to normal after recovery. Measurements of serum activities of matrix metalloproteinases -2 and -9 are proposed for monitoring of the dynamics and treatment efficiency in chronic endometritis.

Activin A and inhibin A differentially regulate human uterine matrix metalloproteinases: potential interactions during decidualization and trophoblast invasion

Embryo implantation and trophoblast invasion are tightly regulated processes, involving sophisticated communication between maternal decidual and fetal trophoblast cells. Decidualization is a prerequisite for successful implantation and is promoted by a number of paracrine agents, including activin A. To understand the downstream mechanisms of activin-promoted decidualization, the effects of activin on matrix metalloproteinases (MMPs) (important mediators of decidualization) were investigated. Activin A stimulated endometrial production of proMMPs-2, -3, -7, -9, and active MMP-2. In contrast, inhibin A was a potent inhibitor of proMMP-2, and antagonized the effect of activin on MMPs. Activin is up-regulated with decidualization, and MMPs-2, -3, and -9 increase in parallel. Furthermore, proMMP-2 production is stimulated when decidualization is accelerated with activin, and suppressed when activin is neutralized, attenuating decidualization. These data support that activin A promotes decidualization through up-regulating MMPs. Previous in vitro evidence proposes further roles for activin and MMPs in promoting trophoblast invasion; therefore, we examined their interrelationships in early human implantation sites. MMPs-7 and -9 were produced by static cytotrophoblast subpopulations, whereas MMP-2 was strikingly up-regulated in invasive extravillous cytotrophoblasts (EVT). Maternal decidua is the primary source of activin, where a role in stimulating MMP-2 in iEVTs can be envisaged. Inhibin was absent from cytotrophoblast populations, except for a dramatic up-regulation in endovascular EVT plugs, coinciding with a down-regulation of MMP-2. This suggests that inhibin may have a role in the cessation of vascular invasion. These data support that activin, via effects on MMPs, is an important factor in the maternal-fetal dialog regulating implantation.

Endocrine regulation of menstruation

In women, endometrial morphology and function undergo characteristic changes every menstrual cycle. These changes are crucial for perpetuation of the species and are orchestrated to prepare the endometrium for implantation of a conceptus. In the absence of pregnancy, the human endometrium is sloughed off at menstruation over a period of a few days. Tissue repair, growth, angiogenesis, differentiation, and receptivity ensue to prepare the endometrium for implantation in the next cycle. Ovarian sex steroids through interaction with different cognate nuclear receptors regulate the expression of a cascade of local factors within the endometrium that act in an autocrine/paracrine and even intracrine manner. Such interactions initiate complex events within the endometrium that are crucial for implantation and, in the absence thereof, normal menstruation. A clearer understanding of regulation of normal endometrial function will provide an insight into causes of menstrual dysfunction such as menorrhagia (heavy menstrual bleeding) and dysmenorrhea (painful periods). The molecular pathways that precipitate these pathologies remain largely undefined. Future research efforts to provide greater insight into these pathways will lead to the development of novel drugs that would target identified aberrations in expression and/or of local uterine factors that are crucial for normal endometrial function.

Endometrial receptivity: Clinical assessment in relation to fertility, infertility, and antifertility

Fertility in humans and other mammalian species depends absolutely on synchronous events that render the developing blastocyst and the receiving uterus competent for implantation. Endometrial receptivity is defined as the period during which the endometrial epithelium acquires functional, but transient, ovarian steroid-dependent status supportive to blastocyst acceptance and implantation. Once inside the uterus, the blastocyst is surrounded by an intact luminal epithelium, which is considered to act as barrier to its attachment, except for this short period of high endometrial receptivity to blastocyst signal(s). Its transport and permeability properties, in conjunction with cellular action of the endometrium and the embryo, have been suggested to influence creation and maintenance of informational and nutritional status of uterine luminal milieu. This period, also termed as the 'window of implantation,' is limited to days 20-24 of menstrual cycle in humans. However, establishment of endometrial receptivity is still a biological mystery that remains unsolved despite marked advances in our understanding of endometrial physiology following extensive research associated with its development and function. This review deals with various structural, biochemical, and molecular events in the endometrium coordinated within the implantation window that constitute essential elements in the repertoire that signifies endometrial receptivity and is aimed to achieve a better understanding of its relationship to fertility, infertility, and for the development of targeted antifertility agents for human use and welfare.

Transcriptional characterizations of differences between eutopic and ectopic endometrium

Endometriosis, defined as the presence of endometrial glandular and stromal cells outside the uterine cavity, is a common gynecological disease with poorly understood pathogenesis. Using laser capture microdissection and a cDNA microarray with 9600 genes/expressed sequence tags (ESTs), we have conducted a comprehensive profiling of gene expression differences between the ectopic and eutopic endometrium taken from 12 women with endometriosis adjusted for menstrual phase and the location of the lesions. With dye-swapping and replicated arrays, we found 904 genes/ESTs that are differentially expressed. We validated the gene expression using real-time RT-PCR. We found that the expression patterns of these genes/ESTs correctly classified the 12 patients into ovarian and nonovarian endometriosis. We identified gene clusters that are location-specific. In addition, we identified several biological themes using Expression Analysis Systematic Explorer. Finally, we identified 79 pathways with over 100 genes with known functions, which include oxidative stress, focal adhesion, Wnt signaling, and MAPK signaling. The identification of these genes and their associated pathways provides new insight. Our findings will stimulate future investigations on molecular genetic mechanisms underlying the pathogenesis of endometriosis.

TIMP-1 as candidate gene for embryo survival in two divergent lines selected for uterine capacity in rabbits

Selection on uterine capacity has been used in animal breeding as a way to improve the litter size. A divergent selection experiment for uterine capacity was performed in rabbits during ten generations. After the first generations of selection, large differences in number of implanted embryos were obtained between high and low lines. The major part of the differences between lines was due to embryo survival. A segregation analysis suggested the presence of a major gene affecting the reproductive traits. The objective of this work was to test the TIMP-1 gene as a candidate gene for embryo survival in rabbits since it stands up as a target for the investigation of reproductive problems in humans. We have analyzed the parental generation of a F2 cross which consists of 8 and 14 animals from the high and low uterine capacity lines, respectively. The rabbit TIMP-1 gene structure and sequence has been determined, including the proximal promoter region. Despite of the absence of polymorphism between lines in the screened regions (CDS, proximal promoter, exon 1, intron 1, and exon 2), a real-time RT-PCR quantification of the TIMP-1 mRNA in oviduct has shown significant differences between high and low lines at 62 hr of gestation, just when rabbit embryos are located in the oviduct, postulating TIMP-1 as an interesting candidate gene to be involved in the phenotypic differences between the two rabbit lines.

Temporal and spatial expression of MMP-2,-9,-14 and their inhibitors TIMP-1,-2,-3 in the corpus luteum of the cycling rhesus monkey

The corpus luteum (CL) is a transient endocrine organ that secretes progesterone to support early pregnancy. If implantation is unsuccessful, luteolysis is initiated. Extensive tissue remodeling occurs during CL formation and luteolysis. In this study, we have studied the possible involvement of MMP-2, -9, -14, and their inhibitors, TIMP-1, -2, -3 in the CL of cycling rhesus monkey at various stages by in situ hybridization, immunohistochemistry and microscopic assessment. The results showed that the MMP-2 mRNA and protein were mainly expressed in the endothelial cells at the early and middle stages of the CL development, while their expressions were observed in the luteal cells at the late stage during luteal regression. MMP-9 protein was detected in the CL at the early and middle stages, and obviously increased at the late stage. The expressions of MMP-14 and TIMP-1 mRNA were high at the early and late stages, and low at the middle stage. TIMP-2 mRNA was high throughout all the stages, the highest level could be observed at the late stage. The TIMP-3 production was detected throughout all the stages, but obviously declined during CL regression. MMP-9, -14 and TIMP-1, -2, -3 were mainly localized in the cytoplasm of the steroidogenic cells. The results suggest that the MMP/TIMP system is involved in regulation of CL development in the primate, and the coordinated expression of MMP-2, -14 and TIMP-1, -3 may have a potential role in the CL formation and the functional maintaining, while the interaction of MMP-2, -9, -14 and TIMP-1, -2, -3 might also play a role in CL regression at the late stage of CL development in the primate.

GnRH actions on rat preovulatory follicles are mediated by paracrine EGF-like factors

Gonadotropin releasing hormone (GnRH) has been shown to mimic the actions of LH/hCG on oocyte maturation and ovulation. Recent studies demonstrated that induction of ovulation by LH/hCG is mediated, at least in part, by transactivation of epidermal growth factor receptors (EGFR) by autocrine/paracrine EGF-like factors activated by metalloproteases. Here we have examined whether the action of GnRH on the preovulatory follicles is exerted through similar mechanisms involving activation of EGFR. The EGFR kinase inhibitor, AG1478, inhibited GnRH-induced oocyte maturation in explanted follicles in vitro. Its inactive analog, AG43, did not affect GnRH-stimulated resumption of meiosis. GnRH, like LH, stimulated transient follicular expression of EGF-like agents, as well as rat cycloxygenase-2 (rCOX-2), rat hyaluronan synthase-2 (rHAS-2), and rat tumor necrosis factor-alpha-stimulated gene 6 (rTSG-6) mRNAs, known ovulatory enzymes. Likewise, GnRH stimulated follicular progesterone synthesis. Conversely AG1478 inhibited all these actions of GnRH. Furthermore, Galardin, a broad-spectrum metalloprotease inhibitor, blocked GnRH-induced oocyte maturation and follicular progesterone synthesis. In conclusion, we have demonstrated that follicular EGF-like factors mediate also the GnRH-stimulation of ovulatory changes, like these of LH/hCG.

Inhibiting matrix metalloproteinases with prinomastat produces abnormalities in fetal growth and development in rats

BACKGROUND

Matrix metalloproteinases (MMPs) play key roles in remodeling of the extracellular matrix during embryogenesis and fetal development. The objective of this study was to determine the effects of prinomastat, a potent selective MMP inhibitor, on fetal growth and development.

METHODS

Prinomastat (25, 100, 250 mg/kg/day, p.o.) was administered to pregnant female Sprague-Dawley rats on gestational days (GD) 6-17. A Cesarian section was carried out on GD 20 and the fetuses were evaluated for viability and skeletal and soft tissue abnormalities.

RESULTS

Prinomastat treatment at the 250 mg/kg/day dose produced a decrease in body weight and food consumption in the dams. A dose-dependent increase in post-implantation loss was observed in the 100 and 250 mg/kg/day-dose groups, resulting in only 22% of the dams having viable litters for evaluation at the 250 mg/kg/day dose. Fetal skeletal tissue variations and malformations were present in all prinomastat treated groups and their frequency increased with dose. Variations and malformation in fetal soft tissue were also increased at the 100 and 250 mg/kg/day doses. Prinomastat also interfered with fetal growth of rat embryo cultures in vitro.

CONCLUSIONS

These data confirm that MMP inhibition has a profound effect on fetal growth and development in vivo and in vitro.

High iNOS mRNA and protein levels during early third trimester suggest a role for NO in prelabor cervical ripening in the bovine

Nitric oxide (NO) plays a key role in the processes leading to cervical softening prior to labor. Inducible nitric oxide synthase (iNOS) contributes most to the increased production of NO during labor, as demonstrated in the rat cervix, or at term pregnancy in women. Changes in expression of iNOS during late gestation have not yet been studied longitudinally in any species, because repeatedly taking biopsies could not be performed. iNOS mRNA (n = 6) and protein expression (n = 3) in serial cervical biopsies of pregnant pluriparous cows taken around days 225, 250, and 275 of pregnancy and within 1.5 hr after calving (d225, d250, d275 and parturition biopsies, respectively) were measured using quantitative RT-PCR and Western blotting. iNOS mRNA expression decreased from the d225 biopsy onwards, differences being significant between the d250 and d275 (P < 0.05) and between the d275 and parturition biopsies (P < 0.05). iNOS protein expression decreased from d225 to d250 onwards. Immunohistochemical analysis of biopsies showed, besides positive staining in endothelium and epithelium, which remained unchanged at different time points, that iNOS expressing cells in the connective tissue cells of early biopsies were predominantly spindle shaped (mostly smooth muscle cells and some fibroblasts). In the parturition biopsies, iNOS reactivity was mainly found in mononuclear leucocytes. These results lead us to suggest that iNOS from spindle shaped cells is involved in prepartum cervical ripening, while iNOS in mononuclear inflammatory cells may be important for local tissue repair mechanisms during postpartum cervical involution.

Seminal plasma and male factor signalling in the female reproductive tract

In mammals, insemination results in the transmission of seminal factors that act, in the female reproductive tract, to promote sperm survival, to "condition" the female immune response to tolerate the conceptus and to organise molecular and cellular changes in the endometrium to facilitate embryo development and implantation. These events are initiated when signalling agents, including transforming growth factor-beta and other cytokines and prostaglandins secreted by seminal vesicle and prostate glands, interact with epithelial cells in the cervix and uterus to activate cytokine synthesis and to induce cellular and molecular changes resembling a classical inflammatory cascade. The consequences are the recruitment and activation of macrophages, granulocytes and dendritic cells, which have immune-regulatory and tissue-remodelling roles that culminate in improved endometrial receptivity to the implanting embryo. Cytokines elicited by seminal activation have embryotrophic properties and also contribute directly to the optimal development of the early embryo. This review summarises our current understanding of the physiology of responses to seminal plasma in the female reproductive tract and considers the evolutionary significance of seminal plasma in influencing female tissues to promote the success of pregnancy.

Roles of LPA3 and COX-2 in implantation

Lysophosphatidic acid (LPA) is a lipid-derived G-protein-coupled receptor (GPCR) agonist that is involved in a variety of physiological and pathological processes, including cell survival, proliferation and differentiation, cytoskeletal rearrangement, cell-cell interactions, tumorigenesis and cell invasion. LPA also stimulates oocyte maturation, the preimplantation development of two- or four-cell embryos to the blastocyst stage and embryo transport in the oviduct. Recent studies revealed that targeted deletion of the LPA(3) receptor results in delayed implantation and altered embryo spacing, and significantly reduced litter size in mice. This was attributable to selective downregulation of uterine cyclooxygenase-2 (COX-2), which generates prostaglandins (PGs) E(2) and I(2). Exogenous administration of PGE(2) or the PGI(2) analogue, carba-prostacyclin, to LPA(3)-deficient female mice rescued delayed implantation but did not prevent defects in embryo spacing. These findings indicate that LPA-induced COX-2 induction has a crucial role in implantation and mammalian reproduction.

Cathepsins in the ovine uterus: regulation by pregnancy, progesterone, and interferon tau

Cathepsins (CTS) are peptidases that have biological roles in degrading extracellular matrix, catabolism of intracellular proteins, and processing of prohormones. Expression of CTSB, CTSD, CTSH, CTSK, CTSL, CTSS, and CTSZ genes was detected in the endometria of cyclic and early pregnant ewes with distinct temporal and spatial expression patterns. In the d 18 and 20 conceptus, expression of CTSB, CTSD, CTSL, and CTSZ mRNA was detected in the trophectoderm. Of particular note, CTSL mRNA was the most abundant CTS mRNA in the ovine endometrium and detected only in the luminal epithelium and superficial glandular epithelium of cyclic and pregnant ewes. CTSL mRNA increased 8-fold between d 10 and 18 in endometria of pregnant ewes, whereas it declined between d 14 and 16 in cyclic ewes. CTSL protein was also detected in conceptus trophectoderm, and pro-CTSL was detected in uterine flushings from ewes between d 12 and 16 of pregnancy. In ovariectomized and catheterized ewes, CTSL mRNA in the endometrium was increased by progesterone and intrauterine injections of ovine interferon (IFN)tau. Other endometrial CTS genes were also regulated by progesterone alone (CTSB, CTSK, CTSS, and CTSZ) or progesterone and IFNtau (CTSH, CTSK, CTSS, and CTSZ). These results indicate that CTS of endometrial and conceptus origin may regulate endometrial remodeling and conceptus implantation, endometrial CTS genes are regulated by ovarian and placental hormones, and CTSL is a novel IFNtau-stimulated gene expressed only in luminal epithelium and superficial glandular epithelium of the endometrium.

Epidermal growth factor receptor signaling is required for normal ovarian steroidogenesis and oocyte maturation

The midcycle luteinizing hormone (LH) surge triggers several tightly linked ovarian processes, including steroidogenesis, oocyte maturation, and ovulation. We designed studies to determine whether epidermal growth factor receptor (EGFR)-mediated signaling might serve as a common regulator of these activities. Our results showed that EGF promoted steroidogenesis in two different in vitro models of oocyte-granulosa cell complexes. Inhibition of the EGFR kinase prevented EGF-induced steroidogenesis in these in vitro systems and blocked LH-induced steroidogenesis in intact follicles primed with pregnant mare serum gonadotropin. Similarly, inhibition of the EGFR kinase attenuated LH-induced steroidogenesis in MA-10 Leydig cells. Together, these results indicate that EGFR signaling is critical for normal gonadotropin-induced steroidogenesis in both male and female gonads. Interestingly, inhibition of metalloproteinase-mediated cleavage of membrane-bound EGF moieties abrogated LH-induced steroidogenesis in ovarian follicles but not MA-10 cells, suggesting that LH receptor signaling activates the EGFR by different mechanisms in these two models. Finally, steroids promoted oocyte maturation in several ovarian follicle models, doing so by signaling through classical steroid receptors. We present a model whereby steroid production may serve as one of many integrated signals triggered by EGFR signaling to promote oocyte maturation in gonadotropin-stimulated follicles.

Matrix Metalloproteinases in Endometrial Breakdown and Repair: Functional Significance in a Mouse Model1

Considerable correlative evidence suggests an important role for matrix metalloproteinases (MMPs) in menstruation, a process which occurs naturally in very few species. In this study, MMP expression was examined in a mouse model of endometrial breakdown and repair and the functional importance of MMPs determined. In the model, progesterone support was withdrawn from mice in which endometrial decidualization had been induced; 24 h later, endometrial breakdown was complete, and the entire decidual zone had been shed. Re-epithelialization had occurred by 36 h, and the endometrium had undergone extensive restoration toward a predecidualized state by 48 h. Immunoreactive MMP9 and MMP7 colocalized with leukocyte subsets, particularly neutrophils, whereas MMP13 staining was always extracellular. MMP3 and MMP7 were abundant during re-epithelialization in close proximity to newly reforming epithelium. The functional importance of MMPs in these processes was examined using two MMP inhibitors, doxycycline and batimistat. Both inhibitors effectively reduced MMP activity, as assessed by in situ zymography, but did not have significant effects on endometrial breakdown or repair. This study demonstrates that although MMPs are present in abundance during endometrial breakdown and repair in this mouse model, they are not the key mediators of these processes.

Suppression of matrix metalloproteinase-9 by prostaglandin E(2) in peritoneal macrophage is associated with severity of endometriosis

Decreased phagocytotic ability of macrophages has been reported to be associated with the severity of endometriosis, although the underlying mechanism remains uncharacterized. Expression and secretion of matrix metalloproteinase (MMP)-9 by macrophages is a means to degrade the extracellular matrix of cells that are designated for phagocytosis. Here, we describe the regulation of MMP-9 expression and activity in peritoneal macrophages of women with endometriosis. Results demonstrated that peritoneal macrophages isolated from women with endometriosis have decreased levels of protein and enzyme activity of MMP-9. Treatment of macrophages with peritoneal fluid obtained from patients with severe endometriosis inhibited MMP-9 expression and gelatinase activity. Further investigation identified prostaglandin (PG) E(2) as the major factor in the peritoneal fluid that inhibited MMP-9 activity. The inhibitory effect of PGE(2) was mediated via the EP2/EP4-dependent PKA pathway. Furthermore, expression of tissue inhibitor of metalloproteinase-1, tissue inhibitor of metalloproteinase-2, and RECK in macrophages was not affected by treatment with PGE(2), indicating the effect of PGE(2) on suppressing MMP-9 activity was not mediated by up-regulation of its inhibitor. Our results suggest that decreased phagocytotic capability of peritoneal macrophage in patients with endometriosis may be caused by PGE(2)-mediated decreases in MMP-9 expression.

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Extracellular matrix in ovarian follicular development and disease

The ovarian follicle contains several different cell types and separate compartments and undergoes substantial development during its growth and maturation. Extracellular matrix (ECM) could be expected to play a major role in these processes. Most research on ECM in follicles has focused on the follicular basal lamina and its changing composition during folliculogenesis and on the specialised matrix formed at ovulation by the cumulus cells surrounding the oocyte and the zona pellucida. We review these aspects. Few naturally occurring gene mutations have identified unique roles for ECM molecules in follicular function. Presumably, any mutations leading to reduced fertility are eliminated quickly by natural selection and, when mutations are not eliminated, considerable redundancy occurs to ensure successful reproduction. In mice, in which the genome can be easily manipulated, the modification of matrix components associated with cumulus and oocytes has often resulted in partial infertility, suggesting redundancy. We provide an update of basal lamina components focusing on newer discoveries. In addition, we review matrix associated with the occyte and cumulus cells (excluding the zona pellucida) and other components of ECM. Where possible, we examine evidence for the role of the ECM in follicular development and diseases.

Functions for proteinases in the ovulatory process

The ovary is a unique and dynamic organ in respect to rapid and extensive degrees of tissue development and remodeling that are periodically repeated in the female reproductive activity. Ovulation is a directed and sequential process accompanied by broad-spectrum proteolysis and culminates in the follicular rupture to release the matured oocyte. This review will focus on the potential roles of six representative proteinases that are involved in various aspects of ovulatory processes: matrix metalloproteinases (MMPs), plasminogen activator (PA)/plasmin, a disintegrin and metalloproteinase domain with thrombospondin motif (ADAMTS), cathepsin-L, pregnancy-associated plasma protein-A (PAPP-A), and bone morphogenetic protein 1/mammalian Tolloid (BMP-1/mTld). Based on the studies of expression and function, these selected proteinases provide and share diverse functions ranging from cleaving components of the extracellular matrix (ECM) to modulating non-ECM molecules, such as various growth factors and their binding proteins. Consistently, the genetic deletion of each individual gene in mice shows their functional overlap in the reproductive activity.

Estrogen receptor-beta is critical to granulosa cell differentiation and the ovulatory response to gonadotropins

The process of granulosa cell differentiation that occurs in preovulatory follicles is dependent on FSH but requires augmentation by estradiol. To determine which estrogen receptor (ER) form mediates the effects of estradiol during gonadotropin-induced follicle growth, differentiation, and rupture, we characterized the response of ERalpha- and ERbeta-null mice to gonadotropin-induced ovulation. Immature mice were treated with an ovulatory regimen of exogenous gonadotropins and tissues were collected at distinct time points for morphological, biochemical, gene expression, and immunohistochemical analyses. Granulosa cells of ERbeta knockout (ERKO) preovulatory follicles exhibited an attenuated response to FSH-induced differentiation, as evident by reduced aromatase activity and estradiol synthesis, and insufficient expression of LH receptor. As a result, betaERKO ovaries were unable to fully respond to an ovulatory bolus of gonadotropin, leading to a reduced rate of follicle rupture; insufficient induction of prostaglandin-synthase 2 and progesterone receptor; an aberrant increase in aromatase activity and plasma estradiol; and incomplete expansion of the cumulus-oocyte complex. Parallel characterization of alphaERKO females indicated a minimal role for ERalpha in granulosa cell differentiation, ovulation, and the concomitant changes in gene expression, although some abnormalities were revealed. These studies demonstrate that ERbeta-mediated estradiol actions are vital to FSH-induced granulosa cell differentiation; and in the absence of ERbeta, preovulatory follicles are deficient in the necessary cellular organization (i.e. antrum and cumulus oocyte complex), enzymatic activity (i.e. capacity to convert androgen precursor to estradiol), and receptor signaling pathways (i.e. LH receptor) to respond to a gonadotropin surge and expel a healthy oocyte.

Expression of Basigin, an Inducer of Matrix Metalloproteinases, in the Rat Ovary1

The extensive tissue remodeling that occurs during follicular development, ovulatory rupture, and the formation and regression of the corpus luteum (CL) requires local degradation of the extracellular environment by matrix metalloproteinases (MMPs). This report characterizes the expression pattern of basigin (Bsg), a putative regulator of MMP induction, in the rat ovary. An induced superovulation model (eCG/hCG) was used in immature rats to evaluate Bsg expression profiles in ovaries collected during the follicular phase, the preovulatory period, and the luteal lifespan. Levels of Bsg mRNA were unchanged through follicular growth (0-48 h post-eCG) and increased during postovulatory luteinization (24 and 48 h post-hCG; P < 0.01). Bsg expression persisted into pseudopregnancy (4-8 days post-hCG) and after functional luteal regression (12 days post-hCG). The profile of Bsg expression during regression of the CL was examined using a model of induced luteolysis. Both functional and structural regression was associated with a decline in Bsg expression levels. Bsg mRNA and protein localized to the theca of preovulatory follicles (12 h post-hCG) and formative and functional CL (24 h-8 days post-hCG). Bsg expression profiles in the induced ovulation and CL regression models were similar to observations made in naturally cycling mature rats. In the cycling ovary, Bsg signaling localized to newly forming CL, the theca of preovulatory follicles, and appeared to be lower in CL from previous estrous cycles. A putative regulatory mechanism of Bsg expression was identified using an in vitro model; treatment of cultured granulosa cells with hCG significantly augmented Bsg mRNA expression levels. The processes of ovulation and luteogenesis may be facilitated by Bsg expression and its induction or regulation of the MMPs.

The effect of human chorionic gonadotrophin on the expression of progesterone receptors in human luteal cells in vivo and in vitro

The human corpus luteum expresses genomic progesterone receptors (PRs) suggesting that progesterone may have an autocrine or paracrine role in luteal function. We hypothesised that the reduction in luteal PR reported in the late-luteal phase augmented progesterone withdrawal and had a role in luteolysis. We therefore tested the hypothesis that luteal rescue with human chorionic gonadotrophin (hCG) would maintain PR expression. PR was immunolocalised to different cell types in human corpora lutea (n = 35) from different stages of the luteal phase and after luteal rescue with exogenous hCG. There was no change in the staining intensity of theca-lutein cell or stromal cell PR throughout the luteal phase or after luteal rescue. In the late-luteal phase, granulosa-lutein cell PR immunostaining was reduced (P < 0.05) but the trend to reduction was also seen after luteal rescue with hCG (P = 0.055). To further investigate the effect of hCG on granulosa-lutein cell PR expression, an in vitro model system of cultured human luteinised granulosa cells was studied. Cells were cultured for 12–13 days exposed to different patterns of hCG and aminoglutethamide to manipulate progesterone secretion (P < 0.0001). Expression of PR A/B and PR B isoforms was examined by quantitative real-time RT-PCR. PR A/B mRNA was lower (P < 0.05) after 11–13 days of culture than after 7 days of culture. This reduction could not be prevented by hCG in the presence (P < 0.05) or absence (P < 0.05) of stimulated progesterone secretion. The expression of PR B mRNA showed a similar pattern (P = 0.054). Simulated early pregnancy in vivo and hCG treatment of luteinised granulosa cells in vitro did not appear to prevent the down-regulation of PR seen during luteolysis.

Identification and characterization of human archaemetzincin-1 and -2, two novel members of a family of metalloproteases widely distributed in Archaea

Systematic analysis of degradomes, the complete protease repertoires of organisms, has demonstrated the large and growing complexity of proteolytic systems operating in all cells and tissues. We report here the identification of two new human metalloproteases that have been called archaemetzincin-1 (AMZ1) and archaemetzincin-2 (AMZ2) to emphasize their close relationship to putative proteases predicted by bioinformatic analysis of archaeal genomes. Both human proteins contain a catalytic domain with a core motif (HEXXHXXGX3CX4CXMX17CXXC) that includes an archetypal zinc-binding site, the methionine residue characteristic of metzincins, and four conserved cysteine residues that are not present at the equivalent positions of other human metalloproteases. Analysis of genome sequence databases revealed that AMZs are widely distributed in Archaea and vertebrates and contribute to the defining of a new metalloprotease family that has been called archaemetzincin. However, AMZ-like sequences are absent in a number of model organisms from bacteria to nematodes. Phylogenetic analysis showed that these enzymes have undergone a complex evolutionary process involving a series of lateral gene transfer, gene loss, and genetic duplication events that have shaped this novel family of metalloproteases. Northern blot analysis showed that AMZ1 and AMZ2 exhibit distinct expression patterns in human tissues. AMZ1 is mainly detected in liver and heart whereas AMZ2 is predominantly expressed in testis and heart, although both are also detectable at lower levels in other tissues. Both human enzymes were produced in Escherichia coli, and the purified recombinant proteins hydrolyzed synthetic substrates and bioactive peptides, demonstrating that they are functional proteases. Finally, these activities were abolished by inhibitors of metalloproteases, providing further evidence that AMZs belong to this catalytic class of proteolytic enzymes.

Reduced progesterone action during endometrial maturation: a potential risk factor for the development of endometriosis

OBJECTIVE

To discuss the role that reduced endometrial responsiveness to progesterone (P) might play in the pathophysiology of endometriosis.

DESIGN

A review of experimental evidence regarding the failure of P to regulate the expression of matrix metalloproteinases (MMPs) in the endometrium of patients with endometriosis.

CONCLUSION(S)

Progesterone and locally produced differentiation factors act cooperatively to reduce MMP expression by maternal endometrial cells within the pro-inflammatory micro-environment of early pregnancy. Our in vitro studies with normal human endometrium demonstrate that prior P exposure not only down-regulates MMP expression, but also limits the ability of locally produced proinflammatory cytokines to stimulate expression of these enzymes. In contrast, endometrial tissues from women with endometriosis demonstrate an altered response to P, allowing a continuous expression of MMPs throughout the secretory phase. Although the factors that influence the loss of P sensitivity in the endometrium of patients with endometriosis have not yet been defined, alterations in cell-cell communication seem to contribute to dysregulated MMP expression. Specifically, proinflammatory cytokines produced by epithelial cells oppose stromal cell responses to P, inhibiting production of key differentiation factors necessary for cell-specific MMP regulation. The resulting loss in normal MMP regulation enhances the invasive capacity of endometrial tissue, promoting ectopic establishment in an experimental model.

Increased soluble interleukin-1 receptor type II proteolysis in the endometrium of women with endometriosis

Numerous functional changes were observed in the intrauterine endometrial tissue of women with endometriosis. Our previous studies revealed a marked decrease in the expression of interleukin-1 receptor type 2 (IL-1RII), a decoy receptor known for its ability to buffer IL-1 effects. The aim of the present study was to assess whether post-translational mechanisms such as proteolysis may contribute to the down-regulation of IL-1RII levels. Our data showed that soluble IL-1RII (sIL-1RII) concentrations released by freshly cultured endometrial tissue were significantly lower in women with endometriosis than in normal women (P < 0.01) and further revealed a statistically significant correlation between increased proteolysis and decreased sIL-1RII levels (P < 0.05; r = -0.47). (125)I-labelled soluble recombinant human IL-1RII ([(125)I]srhIL-1RII) was significantly more degraded in culture supernatant of tissues from women with endometriosis compared to normal women (P < 0.05), and natural tissue inhibitor of matrix metalloproteinase (TIMP)-1 inhibited [(125)I]srhIL-1RII degradation. Incubation of srhIL-1RII with active rhMMP-9 resulted in a dose-dependent degradation of srhIL-1RII as analysed by western blotting. Dual immunofluorescence showed an increased immunostaining for matrix metalloproteinase-9 in situ in the endometrial tissue of women with endometriosis compared to normal women and a decreased immunostaining for IL-1RII. The present study showed a reduced release of sIL-1RII by the endometrial tissue of women with endometriosis and revealed a proteolytic post-translational mechanism which may be involved in the down-regulation of IL-1RII levels. This may enhance IL-1-mediated activation of endometrial cells and contribute to the local immuno-inflammatory process observed in endometriosis patients.

Regulated Expression of ADAMTS Family Members in Follicles and Cumulus Oocyte Complexes: Evidence for Specific and Redundant Patterns During Ovulation1

Protease cascades are essential for many biological events, including the LH-induced process of ovulation. ADAMTS1 (a disintegrin and metalloproteinase with thrombospondin-like repeats-1) is expressed and hormonally regulated in the ovary by LH and the progesterone receptor. To determine whether other family members might be expressed and regulated in the rodent ovary, those closely related to ADAMTS1 (ADAMTS4 and ADAMTS5) were analyzed in the mouse ovary by reverse transcription-polymerase chain reaction as well as by Western blot, immunohistochemical, and immunocytochemical analyses using highly specific antibodies. Prior to ovulation, ADAMTS4 and ADAMTS5 were coexpressed in granulosa cells of most follicles, whereas ADAMTS5 was also present in granulosa cells of atretic follicles. Following ovulation, ADAMTS1 and ADAMTS4 (but not ADAMTS5) were expressed in multiple cell types, including those within the highly vascular ovulation cone that marks the site of follicle rupture, endothelial cells of newly forming corpora lutea, and cumulus cells within the ovulated cumulus cell-oocyte complex (COC). Versican, a substrate for ADAMTS1 and ADAMTS4, colocalized with these proteases and hylauronan on the cumulus cell surface. To further characterize induction of these proteases and associated molecules, COCs and granulosa cells were isolated from preovulatory follicles and treated with FSH. In expanded COCs and differentiated granulosa cells, FSH induced expression of ADAMTS4 and versican message and protein, whereas increased levels of ADAMTS1 protein was observed in the media of granulosa cells where it was stabilized by heparin in this in vitro system. These studies provide the first evidence that ADAMTS1, ADAMTS4, and ADAMTS5 are expressed in spatiotemporal patterns that suggest distinct as well as some overlapping functions that relate to the broad expression pattern of versican in granulosa cells of small follicles, expanded COCs, and endothelial cells of the mouse ovary.

Spatio-Temporal Expression of Matrix Metalloproteinase-26 in Human Placental Trophoblasts and Fetal Red Cells During Normal Placentation1

The processes of implantation and placentation involve the degradation and remodeling of extracellular matrix, cellular proliferation, apoptosis, and differentiation. Evidence indicates that members of the matrix metalloproteinase (MMP) family play crucial roles in these processes. In the present study, we identified the expression and localization of MMP26/endometase/ matrilysin-2 in human placentae at different stages of gestation using methods of reverse transcriptase-polymerase chain reaction, in situ hybridization, and immunohistochemistry. MMP26 was widely localized to villous cytotrophoblast cells, syncytiotrophoblast cells, and to column trophoblasts during early pregnancy. The mRNA and protein level of MMP26 in chorionic villi was highest at Weeks 6-7, and decreased thereafter, reaching its lowest level at the second trimester. The mRNA level was significantly up-regulated in term placenta, while the immunoreactivity remained undetectable. Notably, intense expression of MMP26 was found in fetal nucleated red cells inside the villous capillaries during gestational Weeks 6-9. Strong expression of MMP26 mRNA was also demonstrated in fetal red cells isolated from the whole blood of fetuses at midpregnancy. The expression patterns of MMP26 in human placenta suggests complicated roles for MMP26 during the processes of placentation and hematopoiesis, perhaps working in concert with other members of the MMP family, such as MMP9.

Molecular profiling of polycystic ovaries for markers of cell invasion and matrix turnover

OBJECTIVE

To study gene expression profiles of connective tissue components in polycystic ovaries using complementary deoxyribonucleic acid (cDNA) array technology.

DESIGN

Descriptive study of normal and polycystic human ovarian biopsy samples analyzed by cDNA array hybridizations.

SETTING

Experimental laboratory research.

PATIENT(S)

Eight women with polycystic ovary syndrome (PCOS) and two normally cycling women treated with electrocauterization and hysterectomy, respectively.

INTERVENTIONS

Ovarian biopsy samples.

MAIN OUTCOME MEASURE(S)

Expression levels of 588 genes involved in cellular invasion, extracellular matrix (ECM) turnover, and cell-ECM interactions in polycystic ovaries.

RESULT(S)

A majority of the 30 genes down-regulated in PCOS ovaries represented those related to cell adhesion and motility, as well as angiogenesis, followed by regulators of cell cycle and growth. The 14 up-regulated genes represented those regulating cell fate and development, growth factors, cytokines, chemokines, and cell-cell interactions. Of the 44 transcripts exhibiting marked changes in the cDNA array analysis, only one - proliferating cell nuclear antigen messenger ribonucleic acid (PCNA mRNA) - was systematically down-regulated; 2 transcripts, for CDC27HS protein and CD9 antigen, were down-regulated in 7 out of 8 PCOS samples.

CONCLUSION(S)

The present data suggest that gene expression profiling may become a useful tool to classify PCOS patients into subgroups with different etiologies. Genome-wide expression profiling using microarrays should be performed to better understand the metabolic derangement(s) in PCOS.