Steroidal regulation of uterine edema and tissue inhibitors of metalloproteinase (TIMP)-3 messenger RNA expression is altered in TIMP-1-deficient mice

Decoding the molecular cascade of embryonic-uterine modulators in pregnancy loss of PCOS mother- an "in vivo" study

BACKGROUND

Polycystic ovary syndrome is associated with an increased rate of spontaneous abortion/early pregnancy loss and pups delivered to PCOS animals were abnormal. Currently, assisted reproductive technology has been used to help numerous infertile couples to have their babies. However, there is a low implantation rate after the transfer of embryos. Till now, it could not be concluded whether the reduced pregnancy rates observed were due to abnormal embryos or endometrial modification. Further, transgenic mouse models have been used to find out the molecular deficits behind early pregnancy complications. But, the deletion of crucial genes could lead to systemic deficiencies/embryonic lethality. Also, pregnancy is a complex process with overlapping expression patterns making it challenging to mimic their stage-specific role. Therefore, the motive of the current study was to investigate the probable molecular cascade to decipher the early pregnancy loss in the letrozole-induced PCOS mouse model.

METHODS

PCOS was induced in mice by oral administration of letrozole daily for 21 days. Following, the pregnancy was established and animals were sacrificed on the day 6th of pregnancy. Animals were assessed for early pregnancy loss, hormonal profile, mRNA expression of steroid receptors (Ar, Pr, Esr1/2), decidualization markers (Hox10/11a), adhesion markers (Itgavb3, Itga4b1), matrix metalloproteinases and their endogenous inhibitor (Mmp2/9, Timp1/2) and key mediators of LIF/STAT pathway (Lif, Lifr, gp130, stat3) were analyzed in the embryo implanted region of the uterus. Morphological changes in ovaries and implanted regions of the uterus were assessed.

RESULTS

Mice treated with letrozole demonstrated significant increases in testosterone levels along with a decline in progesterone levels as compared to control animals. PCOS animals also exhibited decreased fertility index and disrupted ovarian and embryo-containing uterus histopathology. Altered gene expression of the steroid receptors and reduced expression of Hox10a, integrins, Mmp9, Timp1/3, Gp130 & Stat3 was observed in the implanted region of the uterus of PCOS animals.

CONCLUSION

Our results reveal that majority of the molecular markers alteration in the establishment of early pregnancy could be due to the aberrant progesterone signaling in the embryonic-uterine tissue of PCOS animals, which further translates into poor fetal outcomes as observed in the current study and in several IVF patients.

TIMP1 may affect goat prolificacy by regulating biological function of granulosa cells

Tissue inhibitor of metalloproteinase 1 (TIMP1) is associated with animal reproductive processes, such as follicular growth, ovulation, luteinization, and embryo development in mammals. The purposes of this study were to explore the expression and localization of TIMP1 in the ovarian tissues and determine the effect of TIMP1 on the function of granulosa cells and the association of TIMP1 with lambing-related genes of the goats. Immunohistochemical analysis showed that TIMP1 protein was strongly expressed by granulosa cells. Enzyme-linked immunosorbent assay (ELISA) results showed that TIMP1 overexpression promoted the secretion of estradiol of granulosa cells after 12, 24, and 48 h of transfection. Moreover, in vitro experiments indicated that TIMP1 had the ability to promote the cell proliferation and elevate the transcriptional levels of four genes associated with goat prolificacy, including BMPR-1B, BMP15, GDF9, and FSHB, in granulosa cells. In conclusion, TIMP1 could be an important molecule in regulating reproductive performance of the goats by affecting estrogen secretion and cell proliferation, as well as the expression of lambing-related genes of granulosa cells in the goats.

Estrogen induces distinct patterns of microRNA expression within the mouse uterus

Control of estrogenic activity within the uterus is evident as unopposed estrogen action is associated with endometrial pathologies such as endometriosis and endometrial carcinoma. MicroRNAs (miRNAs) have emerged as important posttranscriptional regulators, which are postulated to fine-tune the actions of steroids in many systems including the uterus. The objective of the current study was to examine uterine expression of miRNAs in response to estrogen treatment within the mouse uterus using an ovariectomized, steroid-reconstituted mouse model. MicroRNA microarray analysis and subsequent quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) verification revealed that expression of mirn155, mirn429, and mirn451 was significantly increased by estrogen administration whereas mirn181b and mirn204 expression was significantly reduced. Pretreatment with the estrogen receptor (ER) antagonist ICI 182,780 confirmed that estrogen regulation was mediated via the classical ER pathway. This study demonstrates that estrogen regulates specific miRNAs within the murine uterus, which may participate in posttranscriptional regulation of estrogen-regulated genes.

The tissue inhibitors of metalloproteinases (TIMPs): an ancient family with structural and functional diversity

Tissue inhibitors of metalloproteinases (TIMPs) are widely distributed in the animal kingdom and the human genome contains four paralogous genes encoding TIMPs 1 to 4. TIMPs were originally characterized as inhibitors of matrix metalloproteinases (MMPs), but their range of activities has now been found to be broader as it includes the inhibition of several of the disintegrin-metalloproteinases, ADAMs and ADAMTSs. TIMPs are therefore key regulators of the metalloproteinases that degrade the extracellular matrix and shed cell surface molecules. Structural studies of TIMP-MMP complexes have elucidated the inhibition mechanism of TIMPs and the multiple sites through which they interact with target enzymes, allowing the generation of TIMP variants that selectively inhibit different groups of metalloproteinases. Engineering such variants is complicated by the fact that TIMPs can undergo changes in molecular dynamics induced by their interactions with proteases. TIMPs also have biological activities that are independent of metalloproteinases; these include effects on cell growth and differentiation, cell migration, anti-angiogenesis, anti- and pro-apoptosis, and synaptic plasticity. Receptors responsible for some of these activities have been identified and their signaling pathways have been investigated. A series of studies using mice with specific TIMP gene deletions has illuminated the importance of these molecules in biology and pathology.

Hyperphagia and obesity in female mice lacking tissue inhibitor of metalloproteinase-1

Certain matrix metalloproteinases and their regulators, the tissue inhibitors of metalloproteinases (TIMPs), are involved in development and remodeling of adipose tissue. In studying Timp1(<tm1Pds>) mice, which have a null mutation in Timp1 (Timp1(-/-)), we observed that females exhibit increased body weight by 3 months of age due to increased total body lipid and adipose tissue. Whereas Timp1(-/-) mice have increased size and number of adipocytes, they also display increased food intake despite hyperleptinemia, suggesting that alterations in hypothalamic leptin action or responsiveness may underlie their weight gain. Indeed, leptin promotes the expression of Timp1 mRNA in the hypothalamus, and leptin signaling via signal transducer and activator of transcription-3 mediates the expression of hypothalamic Timp1. Furthermore, Timp1(-/-) mice demonstrate increased food intake and altered expression of certain hypothalamic neuropeptide genes prior to elevated weight gain. Thus, whereas previous data suggested roles for matrix metalloproteinases and TIMPs in the regulation of adipose tissue, these data reveal that Timp1 mRNA is induced by leptin in the hypothalamus and that expression and action of Timp1 contributes to the regulation of feeding and energy balance.

Estrogen-induced uterine abnormalities in TIMP-1 deficient mice are associated with elevated plasmin activity and reduced expression of the novel uterine plasmin protease inhibitor serpinb7

Tissue inhibitor of metalloproteinase-1 (TIMP-1) is a multifunctional protein capable of regulating a variety of biological processes in a wide array of tissue and cell types. We have previously demonstrated that TIMP-1 deficient mice exhibit alterations in normal uterine morphology and physiology. Most notably, absence of TIMP-1 is associated with an altered uterine phenotype characterized by profound branching of the uterine lumen and altered adenogenesis. To begin to assess the mechanism by which TIMP-1 may control these uterine events, we utilized steroid-treated ovariectomized wild-type and TIMP-1 null mice exposed to estrogen for 72 hr. Administration of estrogen to TIMP-1 deficient mice resulted in development of an abnormal uterine histo-architecture characterized by increased endometrial gland density, luminal epithelial cell height, and abnormal lumen structure. To determine the mediators which may contribute to the abnormal uterine morphology in the TIMP-1 deficient mice, cDNA microarray analysis was performed. Analysis revealed that expression of two plasmin inhibitors (serpbinb2 and serbinb7) was significantly reduced in the TIMP-1 null mice. Associated with the reduction in expression of these inhibitors was a significant increase in plasmin activity. Localization of the novel uterine serpinb7 revealed that expression was confined to the luminal and glandular epithelial cells. Further, expression of uterine serpinb7 was decreased by estrogen and showed an inverse relationship with plasmin activity. We conclude from these studies that in addition to controlling MMP activity, TIMP-1 may also control activity of serine proteases through modulation of serine protease inhibitors such as serpinb7.

Expression of tissue inhibitor of matrix metalloproteinases (TIMP)-3 protein in invasive breast carcinoma: relation to tumor phenotype and clinical outcome

Introduction

Our aim was to study the expression pattern of tissue inhibitor of metalloproteinases (TIMP)-3 protein in invasive breast carcinoma, and its clinicopathological and prognostic value as well as its relation to markers indicative of the tumor phenotype.

Methods

Immunohistochemistry was performed on paraffin-embedded tissue specimens from 173 invasive breast carcinomas to detect the proteins TIMP-3, estrogen receptor (ER), progesterone receptor, p53, c-erbB-2, topoisomerase IIα and Bcl-2.

Results

TIMP-3 protein was immunodetected in the cytoplasm of the malignant cells and the peritumoral stroma, as well as in in situ carcinoma and normal epithelium. Reduced expression of TIMP-3 protein within cancer cells was correlated with carcinomas of high nuclear and histological grade (p = 0.032 and p = 0.015, respectively), and low ER expression (p = 0.053). Moreover, TIMP-3 immunopositivity was inversely correlated with the expression of p53 and topoIIα proteins (p = 0.002 and p = 0.008, respectively), whereas it was positively associated with Bcl-2 expression (p = 0.020). Reduced expression of TIMP-3 protein within cancer cells was found to have an unfavorable impact on disease-free survival (p = 0.052) in the entirety of the patient population, as well as in both subgroups of lymph-node-positive and mutant-p53-negative patients (p = 0.007 and p = 0.037, respectively). Stromal localization of TIMP-3 protein was found to have no clinicopathological or prognostic value.

Conclusion

This is the first immunohistochemical study to show that TIMP-3 protein within cancer cells is associated with tumor phenotype. Reduced expression of TIMP-3 protein within cancer cells was found to correlate with an aggressive tumor phenotype, negatively affecting the disease-free survival of both subgroups of lymph node-positive and mutant-p53-negative patients.

BARX2 and estrogen receptor-alpha (ESR1) coordinately regulate the production of alternatively spliced ESR1 isoforms and control breast cancer cell growth and invasion

The estrogen receptor-alpha gene (ESR1) was previously identified as a direct target of the homeobox transcription factor BARX2 in MCF7 cells. Here, we show that BARX2 and ESR1 proteins bind to different ESR1 gene promoters and regulate the expression of alternatively spliced mRNAs that encode 66 and 46 kDa ESR1 protein isoforms. BARX2 increases the expression of both ESR1 isoforms; however, it has a greater effect on the 46 kDa isoform, leading to an increased ratio between the 46 and 66 kDa proteins. BARX2 also influences estrogen-dependent processes such as anchorage-independent growth and modulates the expression of the estrogen-responsive genes SOX5, RBM15, Dynein and Mortalin. In addition, BARX2 expression promotes cellular invasion and increases the expression of active matrix metalloproteinase-9 (MMP9). BARX2 also increases the expression of the tissue inhibitor of metalloproteinase (TIMP) genes, TIMP1 and TIMP3, in cooperation with estrogen signaling. Overall, these data indicate that BARX2 and ESR1 may coordinately regulate cell growth, survival and invasion pathways that are critical to breast cancer progression.