The expression and regulation of adrenomedullin in the human endometrium: a candidate for endometrial repair

Calcitonin gene-related peptide and intermedin induce phosphorylation of p44/42 MAPK in primary human lymphatic endothelial cells in vitro

Calcitonin gene-related peptide (CGRP) and adrenomedullin 2/intermedin (AM2/IMD) play important roles in several pathologies, including cardiovascular disease, migraine and cancer. The efficacy of drugs targeting CGRP signalling axis for the treatment of migraine patients is sometimes offset by side effects (e.g. inflammation and microvascular complications, including aberrant neovascularisation in the skin). Recent studies using animal models implicate CGRP in lymphangiogenesis and lymphatic vessel function. However, whether CGRP or AM2/IMD can act directly on lymphatic endothelial cells is unknown. Here, we found that CGRP and AM2/IMD induced p44/42 MAPK phosphorylation in a time- and dose-dependent manner in primary human dermal lymphatic endothelial cells (HDLEC) in vitro, and thus directly affected these cells. These new findings reveal CGRP and AM2/IMD as novel regulators of LEC biology and warrant further investigation of their roles in the context of pathologies associated with lymphatic function in the skin and other organs, and therapies targeting CGRP signalling axis.

Hypoxia and the endometrium: An indispensable role for HIF-1α as therapeutic strategies

Hypoxia-inducible factor 1 alpha (HIF-1α) is a major molecular mediator of the hypoxic response. In the endometrium, local hypoxic conditions induced by hormonal fluctuations and endometrial vascular remodeling contribute to the production of HIF-1α, which plays an indispensable role in a series of physiological activities, such as menstruation and metamorphosis. The sensitive regulation of HIF-1α maintains the cellular viability and regenerative capacity of the endometrium against cellular stresses induced by hypoxia and excess reactive oxygen species. In contrast, abnormal HIF-1α levels exacerbate the development of various endometrial pathologies. This knowledge opens important possibilities for the development of promising HIF-1α-centered strategies to ameliorate endometrial disease. Nonetheless, additional efforts are required to elucidate the regulatory network of endometrial HIF-1α and promote the applications of HIF-1α-centered strategies in the human endometrium. Here, we summarize the role of the HIF-1α-mediated pathway in endometrial physiology and pathology, highlight the latest HIF-1α-centered strategies for treating endometrial diseases, and improve endometrial receptivity.

Quantitative proteomics reveals CLR interactome in primary human cells

The G protein-coupled receptor (GPCR) calcitonin receptor-like receptor (CLR) mediates essential functions in several cell types and is implicated in cardiovascular pathologies, skin diseases, migraine, and cancer. To date, the network of proteins interacting with CLR ("CLR interactome") in primary cells, where this GPCR is expressed at endogenous (physiologically relevant) levels, remains unknown. To address this knowledge gap, we established a novel integrative methodological workflow/approach for conducting a comprehensive/proteome-wide analysis of Homo sapiens CLR interactome. We used primary human dermal lymphatic endothelial cells and combined immunoprecipitation utilizing anti-human CLR antibody with label-free quantitative nano LC-MS/MS and quantitative in situ proximity ligation assay. By using this workflow, we identified 37 proteins interacting with endogenously expressed CLR amongst 4902 detected members of the cellular proteome (by quantitative nano LC-MS/MS) and revealed direct interactions of two kinases and two transporters with this GPCR (by in situ proximity ligation assay). All identified interactors have not been previously reported as members of CLR interactome. Our approach and findings uncover the hitherto unrecognized compositional complexity of the interactome of endogenously expressed CLR and contribute to fundamental understanding of the biology of this GPCR. Collectively, our study provides a first-of-its-kind integrative methodological approach and datasets as valuable resources and robust platform/springboard for advancing the discovery and comprehensive characterization of physiologically relevant CLR interactome at a proteome-wide level in a range of cell types and diseases in future studies.

Epigenetic alternations and targeted therapy in intrauterine adhesion: A comparative study

Although intrauterine adhesion (IUA) has been well recognized as a critical factor in infertility, little information is available regarding the molecular mechanisms. We performed a high-throughput RNA sequencing in the endometrium of three IUA patients and three normal controls. And another two gene expression profiles (PMID34968168 and GSE160365) were analyzed together. A total of 252 DEGs were identified. Cell cycle, E2F target, G2M checkpoint, integrin3 pathway and H1F1 signaling were aberrantly regulated in the IUA endometrium. 10 hub genes (CCL2, TFRC, THY1, IGF1, CTGF, SELL, SERPINE1, HBB, HBA1, LYZ) were exhibited in PPI analysis. FOXM1, IKBKB and MYC were three common transcription factors of DEGs. Five chemicals (MK-1775, PAC-1, TW-37, BIX-01294, 3-matida) were identified as putative therapeutic agents for IUA. Collectively, a series of DEGs associated with IUA were disclosed. Five chemicals and ten hub genes may be further explored as potential drugs and targets for IUA treatment.

Crosstalk between Extracellular Matrix Stiffness and ROS Drives Endometrial Repair via the HIF-1α/YAP Axis during Menstruation

Although the menstrual cycle driven by sex steroid hormones is an uncomplicated physiological process, it is important for female health, fertility and regenerative biology. However, our understanding of this unique type of tissue homeostasis remains unclear. Here, we examined the biological effects of mechanical force by evaluating the changing trend of extracellular matrix (ECM) stiffness, and the results suggested that ECM stiffness was reduced and that breaking of mechanotransduction delayed endometrium repair in a mouse model of simulated menses. We constructed an ECM stiffness interference model in vitro to explain the mechanical force conduction mechanism during endometrial regeneration. We discovered that ECM stiffness increased the expression and nuclear transfer of YAP, which improved the creation of a microenvironment, in a manner that induced proliferation and angiogenesis for endometrial repair by activating YAP. In addition, we observed that physiological endometrial hypoxia occurs during the menstrual cycle and that the expression of HIF-1α was increased. Mechanistically, in addition to the classical F-actin/YAP pathway, we also found that the ROS/HIF-1α/YAP axis was involved in the transmission of mechanical signals. This study provides novel insights into the essential menstrual cycle and presents an effective, nonhormonal treatment for menstrual disorders.

Total alkaloid fraction of Leonurus japonicus Houtt. Promotes angiogenesis and wound healing through SRC/MEK/ERK signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Leonurus japonicus Houtt., also known as motherwort, is a traditional Chinese medicine that was first identified in Shennong Bencao Jing, the first and essential pharmacy monograph in China. L. japonicus has been regarded as a good gynecological medicine since ancient times. It has been widely used in clinical settings for treatment of gynecological diseases and postnatal rehabilitation with good efficacy and low adverse effects.

AIM OF THE STUDY

The main purpose of this study was to determine the angiogenic and wound healing effects of total alkaloid fraction from L. japonicus Houtt. (TALH) in vivo and in vitro. In addition, the main bioactive components of total alkaloids were to be identified and analyzed in this study.

MATERIALS AND METHODS

First, the UHPLC/Q-TOF-MS method was used to identify and quantify the major components in the TALH extract. The wound healing activity was evaluated in vivo using a rat full-thickness cutaneous wound model. Histological study of wound healing in rat model was performed via immunohistochemistry and immunofluorescence. Cell proliferation was determined by MTT assay. Wound healing and transwell assays were used for detection of cell migration. The effect on tube formation was determined by tube formation assay in HUVECs. Western blot and RT-PCR were used to detect the expressions of relative proteins and genes respectively. Knock-down of SRC by siRNA was done to verify the crucial role of SRC in promotion of angiogenesis induced by TALH.

RESULTS

Seven characteristic peaks were recognized in the UHPLC/Q-TOF-MS spectrum, while four of the main components were quantified. The wound model in rats showed that treatment of TALH promoted wound healing by stimulating cellular proliferation and collagen deposition. In vitro experiments showed that co-treatment of TALH and VEGF increased cell proliferation, migration and tube formation in HUVECs. Mechanistic studies suggested that the co-treatment increased gene expressions of SRC, MEK1/2 and ERK1/2, as well as the phosphorylation levels of these proteins. Furthermore, the effect of co-treatment was attenuated after SRC knockdown, suggesting that SRC plays an important role in angiogenesis and wound healing induced by TALH and VEGF co-treatment.

CONCLUSION

Our results showed that TALH was one of the main active components of L. japonicus that promoted angiogenesis and wound healing by regulating the SRC/MEK/ERK pathway. Our study provided scientific basis for better clinical application of L. japonicas.

Inflammation-Related Molecules at the Maternal-Fetal Interface during Pregnancy and in Pathologically Altered Endometrium

The blastocyst expresses paternally derived alloantigens and induces inflammation during implantation. However, it is necessary for the onset of pregnancy. An abnormal response might result in a pathological course of pregnancy or pregnancy failure. On the other hand, a state of maternal immune tolerance is necessary to ensure the normal development of pregnancy by suppressing inflammatory processes. This article discusses recognized mechanisms and the significance of inflammatory processes for embryo implantation and pregnancy establishment. We would also like to present disorders involving excessive inflammatory response and their influence on events occurring during embryo implantation. The chain of correlation between the processes responsible for embryo implantation and the subsequent physiological course of pregnancy is complicated. Many of those interrelationships are still yet to be discovered. Undoubtedly, their recognition will give hope to infertile couples for the emergence of new treatments that will increase the chance of giving birth to a healthy child.

The Menstrual Endometrium: From Physiology to Future Treatments

Abnormal uterine bleeding (AUB) is experienced by up to a third of women of reproductive age. It can cause anaemia and often results in decreased quality of life. A range of medical and surgical treatments are available but are associated with side effects and variable effectiveness. To improve the lives of those suffering from menstrual disorders, delineation of endometrial physiology is required. This allows an increased understanding of how this physiology may be disturbed, leading to uterine pathologies. In this way, more specific preventative and therapeutic strategies may be developed to personalise management of this common symptom. In this review, the impact of AUB globally is outlined, alongside the urgent clinical need for improved medical treatments. Current knowledge of endometrial physiology at menstruation is discussed, focusing on endocrine regulation of menstruation and local endometrial inflammation, tissue breakdown, hypoxia and endometrial repair. The contribution of the specialised endometrial vasculature and coagulation system during menstruation is highlighted. What is known regarding aberrations in endometrial physiology that result in AUB is discussed, with a focus on endometrial disorders (AUB-E) and adenomyosis (AUB-A). Gaps in existing knowledge and areas for future research are signposted throughout, with a focus on potential translational benefits for those experiencing abnormal uterine bleeding. Personalisation of treatment strategies for menstrual disorders is then examined, considering genetic, environmental and demographic characteristics of individuals to optimise their clinical management. Finally, an ideal model of future management of AUB is proposed. This would involve targeted diagnosis of specific endometrial aberrations in individuals, in the context of holistic medicine and with due consideration of personal circumstances and preferences.

Markers of human endometrial hypoxia can be detected in vivo and ex vivo during physiological menstruation

STUDY QUESTION

Can markers of human endometrial hypoxia be detected at menstruation in vivo?

SUMMARY ANSWER

Our in vivo data support the presence of hypoxia in menstrual endometrium of women during physiological menstruation.

WHAT IS KNOWN ALREADY

Current evidence from animal models and human in vitro studies suggests endometrial hypoxia is present at menstruation and drives endometrial repair post menses. However, detection of human endometrial hypoxia in vivo remains elusive.

STUDY DESIGN, SIZE, DURATION

We performed a prospective case study of 16 women with normal menstrual bleeding.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Reproductively aged female participants with a regular menstrual cycle underwent objective measurement of their menstrual blood loss using the alkaline haematin method to confirm a loss of <80 ml per cycle. Exclusion criteria were exogenous hormone use, an intrauterine device, endometriosis or fibroids >3 cm. Participants attended for two MRI scans; during days 1-3 of menstruation and the early/mid-secretory phase of their cycle. The MRI protocol included dynamic contrast-enhanced MRI and T2* quantification. At each visit, an endometrial sample was also collected and hypoxia-regulated repair factor mRNA levels (ADM, VEGFA, CXCR4) were quantified by RT-qPCR.

MAIN RESULTS AND THE ROLE OF CHANCE

Women had reduced T2* during menstrual scans versus non-menstrual scans (P = 0.005), consistent with menstrual hypoxia. Plasma flow (Fp) was increased at menstruation compared to the non-menstrual phase (P = 0.0005). Laboratory findings revealed increased ADM, VEGF-A and CXCR4 at menstruation on examination of paired endometrial biopsies from the menstrual and non-menstrual phase (P = 0.008; P = 0.03; P = 0.009). There was a significant correlation between T2* and these ex vivo hypoxic markers (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

This study examined the in vivo detection of endometrial hypoxic markers at specific timepoints in the menstrual cycle in women with a menstrual blood loss <80 ml/cycle and without significant uterine structural abnormalities. Further research is required to determine the presence of endometrial hypoxia in those experiencing abnormal uterine bleeding with and without fibroids/adenomyosis.

WIDER IMPLICATIONS OF THE FINDINGS

Heavy menstrual bleeding (HMB) is a common, debilitating condition. Understanding menstrual physiology may improve therapeutics. To our knowledge, this is the first in vivo data supporting the presence of menstrual hypoxia in the endometrium of women with normal menstrual bleeding. If aberrant in those with HMB, these non-invasive tests may aid diagnosis and facilitate personalized treatments for HMB.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by Wellbeing of Women grant RG1820, Wellcome Trust Fellowship 209589/Z/17/Z and undertaken in the MRC Centre for Reproductive Health, funded by grants G1002033 and MR/N022556/1. H.O.D.C. has clinical research support for laboratory consumables and staff from Bayer AG and provides consultancy advice (but with no personal remuneration) for Bayer AG, PregLem SA, Gedeon Richter, Vifor Pharma UK Ltd, AbbVie Inc; Myovant Sciences GmbH. H.O.D.C. receives royalties from UpToDate for articles on abnormal uterine bleeding.

TRIAL REGISTRATION NUMBER

N/A.

Comparison of endometrial prostanoid profiles in three infertile subgroups: the missing part of receptivity?

OBJECTIVE

To study the prostanoid profile of the endometria of patients with recurrent implantation failure (RIF), unexplained infertility (UIF), and recurrent miscarriages (RM), and to compare them with the endometria of healthy fertile controls.

DESIGN

Prospective cohort study.

SETTING

University hospital.

PATIENT(S)

Fifteen patients with RIF, 18 patients with UIF, 16 patients with RM, and 23 fertile controls were recruited.

INTERVENTION(S)

Endometrial samples were taken during the window of implantation. After tissue homogenization and extraction, analysis with ultra-performance liquid chromatography diode array detector electrospray ionisation tandem mass spectrometry was performed.

MAIN OUTCOME MEASURES

Concentrations of prostaglandin (PG) D1, PGE1, PGF1α, 6-ketoPGF1α, PGD2, PGE2, PGF2α, 15-deoxy-Δ12,14-PGJ2, PGD3, PGE3, PGF3α, thromboxane B2, 13,14-dihydro-PGE1, 13,14-dihydro-PGF1α, 13,14-dihydro-PGF2α, 13,14-dihydro-15-keto-PGE1, 13,14-dihydro-15-keto-PGE2, and 13,14-dihydro-15-keto-PGF2α were assessed.

RESULT(S)

Comparison of the endometria of patients with UIF and the controls showed no statistically significant differences. When the endometria of patients with RIF were compared with the controls, thromboxane B2 (TXB2) was found significantly higher (843.1 pg/mg vs. 133.5 pg/mg). When the endometria of patients with RM were compared with controls, 13,14-dihydro-15-keto PGF2α and TXB2 were found significantly higher (3907.30 pg/mg vs. 17.80 pg/mg and 858.7 pg/mg vs. 133.5 pg/mg respectively).

CONCLUSION(S)

We identified increased endometrial presence of TXB2 in patients with RM and RIF, and 13,14-dihydro-15-keto PGF2α in patients with RM. Although common ground is observed for RM and RIF, prostanoids, on the other hand, might make their own contribution to endometrial receptivity as important as genes and proteins. Attempts to normalize the prostaglandin profile of the endometrium via enzymatic activity can open new therapeutic options.

Elevated levels of adrenomedullin in eutopic endometrium and plasma from women with endometriosis

OBJECTIVE

To test adrenomedullin (Adm, ADM) as a downstream target of signal transducer and activator of transcription 3 (STAT3) in endometrial cells and to test midregional proadrenomedullin (MR-proADM) as a biomarker of endometriosis.

DESIGN

Cross-sectional analysis of Adm expression in eutopic endometrium and of MR-proADM in plasma from women with and without endometriosis; and prospective study of MR-proADM levels in women with endometriosis undergoing surgical resection of ectopic lesions.

SETTING

Academic medical centers.

PATIENT(S)

Fifteen patients with endometriosis and 11 healthy control subjects who donated eutopic endometrial biopsies; and 28 patients with endometriosis and 19 healthy control subjects who donated plasma for MR-proADM analysis.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Adm mRNA levels according to quantitative real-time polymerase chain reaction after activation of STAT3 by interleukin-6 (IL-6) in Ishikawa cells; immunohistochemistry for ADM in eutopic endometrial biopsies from women with endometriosis compared with healthy donors; and MR-proADM levels measured by commercial immunoassay in plasma from healthy women and women with endometriosis who subsequently underwent surgical resection of ectopic lesions.

RESULT(S)

Activation of STAT3 by IL-6 up-regulated Adm mRNA expression in Ishikawa cells. ADM protein levels were elevated in the eutopic endometrium of women with endometriosis. MR-proADM concentrations were higher in women with endometriosis but were not correlated with disease stage, corrected by surgery, or predictive of fertility outcome.

CONCLUSION(S)

MR-proADM may be able to serve as a biomarker of endometriosis, but it is unknown whether elevated MR-proADM levels are secondary to the estrogenic and inflammatory properties of endometriosis or an inciting pathogenic factor.

Hypoxia and hypoxia inducible factor-1α are required for normal endometrial repair during menstruation

Heavy menstrual bleeding (HMB) is common and debilitating, and often requires surgery due to hormonal side effects from medical therapies. Here we show that transient, physiological hypoxia occurs in the menstrual endometrium to stabilise hypoxia inducible factor 1 (HIF-1) and drive repair of the denuded surface. We report that women with HMB have decreased endometrial HIF-1α during menstruation and prolonged menstrual bleeding. In a mouse model of simulated menses, physiological endometrial hypoxia occurs during bleeding. Maintenance of mice under hyperoxia during menses decreases HIF-1α induction and delays endometrial repair. The same effects are observed upon genetic or pharmacological reduction of endometrial HIF-1α. Conversely, artificial induction of hypoxia by pharmacological stabilisation of HIF-1α rescues the delayed endometrial repair in hypoxia-deficient mice. These data reveal a role for HIF-1 in the endometrium and suggest its pharmacological stabilisation during menses offers an effective, non-hormonal treatment for women with HMB.

Steroids Regulate CXCL4 in the Human Endometrium During Menstruation to Enable Efficient Endometrial Repair

Context

Repair of the endometrial surface at menstruation must be efficient to minimize blood loss and optimize reproductive function. The mechanism and regulation of endometrial repair remain undefined.

Objective

To determine the presence/regulation of CXCL4 in the human endometrium as a putative repair factor at menses.

Patients/Setting

Endometrial tissue was collected throughout the menstrual cycle from healthy women attending the gynecology department. Menstrual blood loss was objectively measured in a subset, and heavy menstrual bleeding (HMB) was defined as >80 mL per cycle. Monocytes were isolated from peripheral blood.

Design

CXCL4 messenger RNA (mRNA) and protein were identified by quantitative reverse transcription polymerase chain reaction and immunohistochemistry. The function/regulation of endometrial CXCL4 was explored by in vitro cell culture.

Results

CXCL4 mRNA concentrations were significantly increased during menstruation. Intense staining for CXCL4 was detected in late secretory and menstrual tissue, localized to stromal, epithelial and endothelial cells. Colocalization identified positive staining in CD68+ macrophages. Treatment of human endometrial stromal and endothelial cells (hESCs and HEECs, respectively) with steroids revealed differential regulation of CXCL4. Progesterone withdrawal resulted in significant increases in CXCL4 mRNA and protein in hESCs, whereas cortisol significantly increased CXCL4 in HEECs. In women with HMB, CXCL4 was reduced in endothelial cells during the menstrual phase compared with women with normal menstrual bleeding. Cortisol-exposed macrophages displayed increased chemotaxis toward CXCL4 compared with macrophages incubated with estrogen or progesterone.

Conclusions

These data implicate CXCL4 in endometrial repair after menses. Reduced cortisol at the time of menses may contribute to delayed endometrial repair and HMB, in part by mechanisms involving aberrant expression of CXCL4.

The role of immunohistochemical adrenomedullin and Bcl-2 expression in development of type-1 endometrial adenocarcinoma: Adrenomedullin expression in endometrium

BACKGROUND

Adrenomedullin (AM) is a pluripotent peptide first discovered from human pheochromocytoma. AM expression has been shown in various cancer types including endometrium cancer. Bcl-2 is an antiapoptotic protein which might be regulated by AM in hypoxic conditions. The aim of the present study was to investigate the role of AM and Bcl-2 expressions in carcinogenesis of type-1 endometrium cancer.

MATERIALS AND METHOD

Study group consisted of 10 proliferative endometrium, 22 simple endometrial hyperplasia, 23 endometrial intraepithelial neoplasia (EIN) and 30 Grade 1 endometrioid adenocarcinoma patients. AM and Bcl-2 expressions were investigated by immunohistochemistry.

RESULTS

Mean AM Allred score was 3±2.6, 5.6±1.6 and 5.7±2.5 in benign, EIN and adenocarcinoma groups, respectively. AM expression was significantly higher in EIN and adenocarcinoma groups than in benign endometrium group (p<0.05). Mean Bcl-2 Allred score was 6.4±2.1, 5.2±2.6, 2.3±2 in benign endometrium, EIN and adenocarcinoma groups, respectively. Mean Bcl-2 Allred score was similar between benign endometrium and EIN groups (p>0.05). However, it was significantly lower in adenocarcinoma group (p<0.05). An inverse correlation between AM and Bcl-2 expressions was found (r: -0.4, p<0.001).

CONCLUSIONS

Our findings showed that AM expression increased in progression from benign endometrium to EIN and type-1 adenocarcinoma while expression of Bcl-2 decreased in transition from EIN to carcinoma.

The role of decidual cells in uterine hemostasis, menstruation, inflammation, adverse pregnancy outcomes and abnormal uterine bleeding

BACKGROUND

Human pregnancy requires robust hemostasis to prevent hemorrhage during extravillous trophoblast (EVT) invasion of the decidualized endometrium, modification of spiral arteries and post-partum processes. However, decidual hemorrhage (abruption) can occur throughout pregnancy from poorly transformed spiral arteries, causing fetal death or spontaneous preterm birth (PTB), or it can promote the aberrant placentation observed in intrauterine growth restriction (IUGR) and pre-eclampsia; all leading causes of perinatal or maternal morbidity and mortality. In non-fertile cycles, the decidua undergoes controlled menstrual bleeding. Abnormal uterine bleeding (AUB) accompanying progestin-only, long-acting, reversible contraception (pLARC) accounts for most discontinuations of these safe and highly effective agents, thereby contributing to unwanted pregnancies and abortion. The aim of this study was to investigate the role of decidual cells in uterine hemostasis, menstruation, inflammation, adverse pregnancy outcomes and abnormal uterine bleeding.

METHODS

We conducted a critical review of the literature arising from PubMed searches up to December 2015, regarding in situ and in vitro expression and regulation of several specific proteins involved in uterine hemostasis in decidua and cycling endometrium. In addition, we discussed clinical and molecular mechanisms associated with pLARC-induced AUB and pregnancy complications with abruptions, chorioamnionitis or pre-eclampsia.

RESULTS

Progestin-induced decidualization of estradiol-primed human endometrial stromal cells (HESCs) increases in vivo and in vitro expression of tissue factor (TF) and type-1 plasminogen activator inhibitor (PAI-1) while inhibiting plasminogen activators (PAs), matrix metalloproteinases (MMPs), and the vasoconstrictor, endothelin-1 (ET-1). These changes in decidual cell-derived regulators of hemostasis, fibrinolysis, extracellular matrix (ECM) turnover, and vascular tone prevent hemorrhage during EVT invasion and vascular remodeling. In non-fertile cycles, progesterone withdrawal reduces TF and PAI-1 while increasing PA, MMPs and ET-1, causing menstrual-associated bleeding, fibrinolysis, ECM degradation and ischemia. First trimester decidual hemorrhage elicits later adverse outcomes including pregnancy loss, pre-eclampsia, abruption, IUGR and PTB. Decidual hemorrhage generates excess thrombin that binds to decidual cell-expressed protease-activated receptors (PARs) to induce chemokines promoting shallow placentation; such bleeding later in pregnancy generates thrombin to down-regulate decidual cell progesterone receptors and up-regulate cytokines and MMPs linked to PTB. Endometria of pLARC users display ischemia-induced excess vasculogenesis and progestin inhibition of spiral artery vascular smooth muscle cell proliferation and migration leading to dilated fragile vessels prone to bleeding. Moreover, aberrant TF-derived thrombin signaling also contributes to the pathogenesis of endometriosis via induction of angiogenesis, inflammation and cell survival.

CONCLUSION

Perivascular decidualized HESCs promote endometrial hemostasis during placentation yet facilitate menstruation through progestational regulation of hemostatic, proteolytic, and vasoactive proteins. Pathological endometrial hemorrhage elicits excess local thrombin generation, which contributes to pLARC associated AUB, endometriosis and adverse pregnancy outcomes through several biochemical mechanisms.

Adrenomedullin in lymphangiogenesis: from development to disease

Over the past decade, we have begun to appreciate that the lymphatic vascular system does more than simply return plasma back into the circulatory system and, in fact, contributes to a wide variety of normal and disease states. For this reason, much research has been devoted to understanding how lymphatic vessels form and function, with a particular interest in which molecules contribute to lymphatic vessel growth and maintenance. In the following review, we focus on a potent lymphangiogenic factor, adrenomedullin, and its known roles in lymphangiogenesis, lymphatic function, and human lymphatic disease. As one of the first, pharmacologically tractable G protein-coupled receptor pathways characterized in lymphatic endothelial cells, the continued study of adrenomedullin effects on the lymphatic system may open new avenues for the modulation of lymphatic growth and function in a variety of lymphatic-related diseases that currently have few treatments.

Hypoxia-controlled EphA3 marks a human endometrium-derived multipotent mesenchymal stromal cell that supports vascular growth

Eph and ephrin proteins are essential cell guidance cues that orchestrate cell navigation and control cell-cell interactions during developmental tissue patterning, organogenesis and vasculogenesis. They have been extensively studied in animal models of embryogenesis and adult tissue regeneration, but less is known about their expression and function during human tissue and organ regeneration. We discovered the hypoxia inducible factor (HIF)-1α-controlled expression of EphA3, an Eph family member with critical functions during human tumour progression, in the vascularised tissue of regenerating human endometrium and on isolated human endometrial multipotent mesenchymal stromal cells (eMSCs), but not in other highly vascularised human organs. EphA3 affinity-isolation from human biopsy tissue yielded multipotent CD29⁺/CD73⁺/CD90⁺/CD146⁺ eMSCs that can be clonally propagated and respond to EphA3 agonists with EphA3 phosphorylation, cell contraction, cell-cell segregation and directed cell migration. EphA3 silencing significantly inhibited the ability of transplanted eMSCs to support neovascularisation in immunocompromised mice. In accord with established roles of Eph receptors in mediating interactions between endothelial and perivascular stromal cells during mouse development, our findings suggest that HIF-1α-controlled expression of EphA3 on human MSCs functions during the hypoxia-initiated early stages of adult blood vessel formation.

Adrenomedullin and endocrine control of immune cells during pregnancy

The immunology of pregnancy is complex and incompletely understood. Aberrant immune activity in the decidua and in the placenta is believed to play a role in diseases of pregnancy, such as infertility, miscarriage, fetal growth restriction and preeclampsia. Here, we briefly review the endocrine control of uterine natural killer cell populations and their functions by the peptide hormone adrenomedullin. Studies in genetic animal models have revealed the critical importance of adrenomedullin dosage at the maternal-fetal interface, with cells from both the maternal and fetal compartments contributing to essential aspects underlying appropriate uterine receptivity, implantation and vascular remodeling of spiral arteries. These basic insights into the crosstalk between the endocrine and immune systems within the maternal-fetal interface may ultimately translate to a better understanding of the functions and consequences of dysregulated adrenomedullin levels in clinically complicated pregnancies.

Expression of hypoxia-inducible factor-1α, endothelin-1 and adrenomedullin in newborn rats with hypoxia-induced pulmonary hypertension

Hypoxia-inducible factor (HIF)-1α is associated with hypoxia-induced pulmonary hypertension (HPH) in adults. In the present study, the expression levels of HIF-1α, endothelin (ET)-1 and adrenomedullin (ADM) were analyzed during HPH in neonates. In total, 96 newborn rats were subjected to hypoxia or normoxia for 3, 5, 7, 10, 14 or 21 days (n=8 per subgroup). HIF-1α, ET-1 and ADM expression levels were measured by quantitative polymerase chain reaction. In addition, the intima-media thickness/external diameter ratio (MT%) and medial wall cross-sectional area/vessel total cross-sectional area ratio (MA%) were calculated to evaluate pulmonary vascular remodeling. The mean pulmonary arterial pressure (mPAP) increased with exposure to hypoxia. Furthermore, the expression levels of HIF-1α, ET-1 and ADM in the lungs were shown to increase after three and five days of hypoxia, while the MT% and MA% increased after seven days of hypoxia, as compared with the controls (P<0.05). Therefore, the expression of HIF-1α, ET-1 and ADM is upregulated in the lungs of newborn rats during early HPH. At later stages, the mPAP increases, vascular remodeling occurs and HIF-1α, ET-1 and ADM expression levels restore to normal levels.

Galectin-7 is important for normal uterine repair following menstruation

Menstruation involves the shedding of the functional layer of the endometrium in the absence of pregnancy. At sites where tissue shedding is complete, re-epithelialization of the tissue is essential for repair and termination of bleeding. The complement of growth factors that mediate post-menstrual endometrial repair are yet to be completely elucidated. Galectins regulate many cell functions important for post-menstrual repair, such as cell adhesion and migration. Galectin-7 has a well characterized role in re-epithelialization and wound healing. We hypothesized that galectin-7 would be important in re-epithelialization during post-menstrual repair. We aimed to identify endometrial expression of galectin-7 in women undergoing normal endometrial repair and in women with amenorrhoea who do not experience endometrial breakdown and repair, and to determine whether galectin-7 enhances endometrial re-epithelialization in vitro. Galectin-7 immunolocalized to the endometrial luminal and glandular epithelium during the late secretory and menstrual phases, and to decidualized stroma in regions exhibiting tissue breakdown. Immunostaining intensity was significantly reduced in the endometrium of women with amenorrhoea compared with normally cycling woman. ELISA identified galectin-7 in menstrual fluid at significantly elevated levels compared with matched peripheral plasma. Exogenous galectin-7 (2.5 µg/ml) significantly enhanced endometrial epithelial wound repair in vitro; this was abrogated by inhibition of integrin binding. Galectin-7 elevated epithelial expression of extracellular matrix-related molecules likely involved in repair including β-catenin, contactin and TGF-β1. In conclusion, galectin-7 is produced by the premenstrual and menstrual endometrium, where it accumulates in menstrual fluid and likely acts as a paracrine factor to facilitate post-menstrual endometrial re-epithelialization.

Hypoxia and lymphangiogenesis in tumor microenvironment and metastasis

Hypoxia and lymphangiogenesis are closely related processes that play a pivotal role in tumor invasion and metastasis. Intratumoral hypoxia is exacerbated as a result of oxygen consumption by rapidly proliferating tumor cells, insufficient blood supply and poor lymph drainage. Hypoxia induces functional responses in lymphatic endothelial cells (LECs), including cell proliferation and migration. Multiple factors (e.g., ET-1, AP-1, C/EBP-δ, EGR-1, NF-κB, and MIF) are involved in the events of hypoxia-induced lymphangiogenesis. Among them, HIF-1α is known to be the master regulator of cellular oxygen homeostasis, mediating transcriptional activation of lymphangiogenesis via regulation of signaling cascades like VEGF-A/-C/-D, TGF-β and Prox-1 in experimental and human tumors. Although the underlying molecular mechanisms remain incompletely elucidated, the investigation of lymphangiogenesis in hypoxic conditions may provide insight into potential therapeutic targets for lymphatic metastasis.

The G-protein-coupled receptor CLR is upregulated in an autocrine loop with adrenomedullin in clear cell renal cell carcinoma and associated with poor prognosis

PURPOSE

The G-protein-coupled receptor (GPCR) calcitonin receptor-like receptor (CLR) and its ligand peptide adrenomedullin (encoded by ADM gene) are implicated in tumor angiogenesis in mouse models but poorly defined in human cancers. We therefore investigated the diagnostic/prognostic use for CLR in human tumor types that may rely on adrenomedullin signaling and in clear cell renal cell carcinoma (RCC), a highly vascular tumor, in particular.

EXPERIMENTAL DESIGN

In silico gene expression mRNA profiling microarray study (n = 168 tumors) and cancer profiling cDNA array hybridization (n = 241 pairs of patient-matched tumor/normal tissue samples) were carried out to analyze ADM mRNA expression in 13 tumor types. Immunohistochemistry on tissue microarrays containing patient-matched renal tumor/normal tissues (n = 87 pairs) was conducted to study CLR expression and its association with clinicopathologic parameters and disease outcome.

RESULTS

ADM expression was significantly upregulated only in RCC and endometrial adenocarcinoma compared with normal tissue counterparts (P < 0.01). CLR was localized in tumor cells and vessels in RCC and upregulated as compared with patient-matched normal control kidney (P < 0.001). Higher CLR expression was found in advanced stages (P < 0.05), correlated with high tumor grade (P < 0.01) and conferred shorter overall survival (P < 0.01).

CONCLUSIONS

In human tissues ADM expression is upregulated in cancer type-specific manner, implicating potential role for adrenomedullin signaling in particular in RCC, where CLR localization suggests autocrine/paracrine mode for adrenomedullin action within the tumor microenvironment. Our findings reveal previously unrecognized CLR upregulation in an autocrine loop with adrenomedullin in RCC with potential application for this GPCR as a target for future functional studies and drug development.

Adrenomedullin haploinsufficiency predisposes to secondary lymphedema

Secondary lymphedema is a debilitating condition, and genetic factors predisposing to its development remain largely unknown. Adrenomedullin (AM) is peptide encoded, together with proadrenomedullin N-terminal peptide (PAMP), by the Adm gene (adrenomedullin gene). AM and its putative receptor calcitonin receptor-like receptor (CLR) are implicated in angiogenesis and lymphangiogenesis during embryogenesis and wound healing, suggesting their possible involvement in secondary lymphedema. To investigate whether AM deficiency predisposes to secondary lymphedema, we used heterozygous adult mice with Adm gene-knockin stop mutation, which selectively abrogated AM, but preserved PAMP, expression (Adm(AM+/Δ) animals). After hind limb skin incision, Adm messenger RNA expression was upregulated in wounded tissue of both Adm(AM+/+) and Adm(AM+/Δ) mice. However, only Adm(AM+/Δ) animals developed limb swelling and histopathological lymphedematous changes, including epidermal thickening, elevated collagen fiber density, and increased microvessel diameter. Secondary lymphedema was prevented when circulating AM levels in Adm(AM+/Δ) mice were restored by systemic peptide delivery. In human skin, CLR was expressed in tissue components affected by lymphedema, including epidermis, lymphatics, and blood vessels. Our study identified a previously unrecognized role for endogenous AM as a key factor in secondary lymphedema pathogenesis and provided experimental in vivo evidence of an underlying germ-line genetic predisposition to developing this disorder.

The endometrial lymphatic vasculature: function and dysfunction

The endometrium has a complex and dynamic blood and lymphatic vasculature which undergoes regular cycles of growth and breakdown. While we now have a detailed picture of the endometrial blood vasculature, our understanding of the lymphatic vasculature in the endometrium is limited. Recent studies have illustrated that the endometrium contains a population of lymphatic vessels with restricted distribution in the functional layer relative to the basal layer. The mechanisms responsible for this restricted distribution and the consequences for endometrial function are not known. This review will summarise our current understanding of endometrial lymphatics, including the mechanisms regulating their growth and function. The potential contribution of lymphatic vessels and lymphangiogenic growth factors to various endometrial disorders will be discussed.

Inflammation, leukocytes and menstruation

Menstruation has many of the features of an inflammatory process. The complexity and sequence of inflammatory-type events leading to the final tissue breakdown and bleeding are slowly being unravelled. Progesterone has anti-inflammatory properties, and its rapidly declining levels (along with those of estrogen) in the late secretory phase of each non-conception cycle, initiates a sequence of interdependent events of an inflammatory nature involving local inter-cellular interactions within the endometrium. Intracellular responses to loss of progesterone (in decidualized stromal, vascular and epithelial cells) lead to decreased prostaglandin metabolism and loss of protection from reactive oxygen species (ROS). Increased ROS results in release of NFκB from suppression with activation of target gene transcription and increased synthesis of pro-inflammatory prostaglandins, cytokines, chemokines and matrix metalloproteinases (MMP). The resultant leukocyte recruitment, with changing phenotypes and activation, provide further degradative enzymes and MMP activators, which together with a hypoxic environment induced by prostaglandin actions, lead to the tissue breakdown and bleeding characteristic of menstruation. In parallel, at sites where shedding is complete, microenvironmentally-induced changes in phenotypes of neutrophils and macrophages from pro- to anti-inflammatory, in addition to induction of growth factors, contribute to the very rapid re-epithelialization and restoration of tissue integrity.

Steroid regulation of menstrual bleeding and endometrial repair

The ovarian steroid hormones progesterone and estradiol are well established regulators of human endometrial function. However, more recent evidence suggests that androgens and locally generated steroids, such as the glucocorticoids, also have a significant impact on endometrial breakdown and repair. The temporal and spatial pattern of steroid receptor presence in endometrial cells has a significant impact on the endometrial response to steroids. Furthermore, regulation of steroid receptor function by modulatory proteins further refines local responses. This review focuses on steroid regulation of endometrial function during the luteo-follicular transition with a focus on menstruation and endometrial repair.

The presence and regulation of connective tissue growth factor in the human endometrium

BACKGROUND

The human endometrium efficiently repairs each month after menstruation. The mechanisms involved in this repair process remain undefined. Aberrations in endometrial repair may lead to the common disorder of heavy menstrual bleeding. We hypothesized that connective tissue growth factor (CTGF) is increased at the time of endometrial repair post-menses and that this increase is regulated by prostaglandins (PGs) and hypoxic conditions present during menstruation.

METHODS AND RESULTS

Examination of 41 endometrial biopsies from 5 stages of the menstrual cycle revealed maximal CTGF mRNA expression (using quantitative RT-PCR) at menstruation and peak protein levels during the proliferative phase. CTGF was immunolocalized to epithelial and stromal cells, with intense staining of occasional stromal cells during the proliferative phase. Dual immunohistochemistry identified these cells as macrophages. Treatment of endometrial epithelial cells with 100 nM PGE(2), PGF(2α) or hypoxia (0.5% O(2)) revealed a significant increase in CTGF mRNA expression (P < 0.01 for all, versus vehicle control). Cells treated simultaneously with PGE(2) and hypoxia revealed a synergistic increase in CTGF expression (P < 0.05 versus PGE(2) or hypoxia alone) and maximal secreted CTGF protein levels (P < 0.05 versus control).

CONCLUSIONS

CTGF is increased in the human endometrium at the time of endometrial repair post-menses. The increase in CTGF may be mediated by PG production and the transient hypoxic episode observed in the endometrium at menstruation.

Adrenomedullin interacts with VEGF in endometrial cancer and has varied modulation in tumours of different grades

OBJECTIVE

Endometrial cancer, in developed countries, is the most common malignancy of the female genital tract. Surgery and radiotherapy are successful in many patients but systemic and recurrent diseases have no consistently effective treatments, and for high grade advanced disease the prognosis is poor. The study investigated characteristics of adrenomedullin in endometrial cancer to assist in identifying targets for developing treatments.

METHODS

Endometrial samples of women with and without cancer, and the Ishikawa cell line were used to investigate adrenomedullin mRNA regulation, peptide expression, adrenomedullin secretion and effects of adrenomedullin on VEGF secretion.

RESULTS

Expression of adrenomedullin mRNA was upregulated compared to that in healthy post-menopausal endometria. Adrenomedullin secretion was increased by cobalt chloride in this study. Secretion was reduced by the naturally-occurring compounds, (-)-epigallocatechin gallate (EGCG) and 3,4',5-trihydroxystilbene (resveratrol), which we have previously demonstrated to also suppress VEGF secretion in endometrial tumour tissue. We noted, for the first time, that adrenomedullin enhanced VEGF secretion from tumour cells.

CONCLUSIONS

Increased adrenomedullin expression may result in amplifying both tumorigenic and angiogenic activities. A substantial impact on growth of tumours may result in vivo as a consequence of the synergism between adrenomedullin and VEGF. Adrenomedullin, which has altered cellular characteristics in tumour compared to healthy tissue, offers an understudied target with potential to modify endometrial cancer behaviour, complementing other treatments.