Angiogenesis In Endometriosis Research Articles

Exosomal miR-21-5p derived from endometrial stromal cells promotes angiogenesis by targeting TIMP3 in ovarian endometrial cysts.

Endometriosis is a multifactorial gynecological disease, with angiogenesis as a key hallmark. The role of exosomal microRNAs (miRNAs) in endometriosis is not well understood. This study investigates differentially expressed exosomal miRNAs linked to angiogenesis in endometriosis, clarifies their molecular mechanisms, and identifies potential targets. Primary endometrial stromal cells (ESCs) were cultured, and exosomes were extracted. In a co-culture system, ESC-derived exosomes were taken up by human umbilical vein endothelial cells (HUVECs). Endometriosis implant-ESC-derived exosomes (EI-EXOs) significantly promoted HUVEC proliferation, migration and tube formation compared to normal endometrium-exosomes (NE-EXOs), a finding consistent in vivo in mice. MiRNA sequencing and bioinformatics identified differentially expressed miR-21-5p from EI-EXOs, confirmed by RT-qPCR. The miR-21-5p inhibitor or GW4869 attenuated EI-EXO-induced HUVEC proliferation, migration, and tube formation. TIMP3 overexpression diminished the pro-angiogenic effect of EI-EXOs, which was reversed by adding EI-EXOs or upregulating miR-21-5p. These findings validate the crosstalk between ESCs and HUVECs mediated by exosomal miR-21-5p, and confirm the miR-21-5p-TIMP3 axis in promoting angiogenesis in endometriosis. KEY MESSAGES: ESC-derived exosomes were found to be taken up by recipient cells, i.e. HUVECs. Functionally, endometriosis implant-ESC-derived exosomes (EI-EXOs) could significantly promote the proliferation, migration and tube formation of HUVECs compared to normal endometrium-exosomes (NE-EXOs). Through miRNA sequencing and bioinformatics analysis, differentially expressed miR-21-5p released by EI-EXOs was chosen, as confirmed by qRT-PCR. miR-21-5p inhibitor or GW4869 was found to attenuate the proliferation, migration, and tube formation of HUVECs induced by EI-EXOs. In turn, TIMP3 overexpression diminished the pro-angiogenic effect of EI-EXOs, and this angiogenic phenotype was reversed once EI-EXOs were added or miR-21-5p was upregulated.

Cannabidiol as a possible treatment for endometriosis through suppression of inflammation and angiogenesis.

Endometriosis is associated with a wide variety of signs and symptoms and can lead to infertility, embryo death, and even miscarriage. Although the exact pathogenesis and etiology of endometriosis is still unclear, it has been shown that it has a chronic inflammatory nature and angiogenesis is also involved in it. This review aims to explore the role of inflammation and angiogenesis in endometriosis and suggest a potential treatment targeting these pathways. Among the pro-inflammatory cytokines, studies have shown solid roles for interleukin 1β (IL-β), IL-6, and tumor necrosis factor α (TNF-α) in the pathogenesis of this condition. Other than inflammation, angiogenesis, the formation of new blood vessels from pre-existing capillaries, is also involved in the pathogenesis of endometriosis. Among angiogenic factors, vascular endothelial growth factor (VEGF), hypoxia-inducible factor 1α (HIF-1α), transforming growth factor β1 (TGF-β1), and matrix metalloproteinases (MMPs) are more essential in the pathogenesis of endometriosis. Interestingly, it has been shown that inflammation and angiogenesis share some similar pathways with each other that could be potentially targeted for treatment of diseases caused by these two processes. Cannabidiol (CBD) is a non-psychoactive member of cannabinoids which has well-known and notable anti-inflammatory and antiangiogenic properties. This agent has been shown to decrease IL-1β, IL-6, TNF-α, VEGF, TGFβ, and MMPs in different animal models of diseases. It seems that CBD could be a possible treatment for endometriosis due to its anti-inflammatory and antiangiogenic activity, however, further studies are needed.

The effect of GnRH-a on the angiogenesis of endometriosis

PurposeNeoangiogenesis is necessary for adhesion and invasiveness of endometriotic lesions in women affected by endometriosis. Vascular endothelial growth factor (VEGF) is one of the main components of angiogenesis and is part of the major pathway tissue factor (TF)-protease activated receptor-2 (PAR-2)-VEGF that leads to neoangiogenesis. Specificity protein 1 (SP1) is a transcriptional factor that has recently been studied for its crucial role in angiogenesis via a specific pathway. We hypothesize that by blocking angiogenetic pathways we can suppress endometriotic lesions. Gonadotrophin-releasing hormone-agonists (GnRH-a) are routinely used, especially preoperatively, in endometriosis. It would be of great interest to clarify which angiogenetic pathways are affected and, thereby, pave the way for further research into antiangiogenetic effects on endometriosis.MethodsWe used quantitative real-time polymerase chain reaction (qRT-PCR) to study mRNA expression levels of TF, PAR-2, VEGF, and SP1 in endometriotic tissues of women who underwent surgery for endometriosis and received GnRH-a (leuprolide acetate) preoperatively.ResultsVEGF, TF, and PAR-2 expression is significantly lower in patients who received treatment (p < 0,001) compared to those who did not, whereas SP1 expression is not altered (p = 0.779).ConclusionsGnRH-a administration does affect some pathways of angiogenesis in endometriotic lesions, but not all of them. Therefore, supplementary treatments that affect the SP1 pathway of angiogenesis should be developed to enhance the antiangiogenetic effect of GnRH-a in patients with endometriosis.Trial registrationClinicaltrial.gov ID: NCT06106932.

Imaging of Endometriotic Lesions Using cRGD-MN Probe in a Mouse Model of Endometriosis

Approximately 10% of women suffer from endometriosis during their reproductive years. This disease is a chronic debilitating condition whose etiology for lesion implantation and survival heavily relies on adhesion and angiogenic factors. Currently, there are no clinically approved agents for its detection. In this study, we evaluated cRGD-peptide-conjugated nanoparticles (RGD-Cy5.5-MN) to detect lesions using magnetic resonance imaging (MRI) in a mouse model of endometriosis. We utilized a luciferase-expressing murine suture model of endometriosis. Imaging was performed before and after 24 h following the intravenous injection of RGD-Cy5.5-MN or control nanoparticles (Cy5.5-MN). Next, we performed biodistribution of RGD-Cy5.5-MN and correlative fluorescence microscopy of lesions stained for CD34. Tissue iron content was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). Our results demonstrated that targeting endometriotic lesions with RGD-Cy5.5-MN resulted in a significantly higher delta T2* upon its accumulation compared to Cy5.5-MN. ICP-OES showed significantly higher iron content in the lesions of the animals in the experimental group compared to the lesions of the animals in the control group. Histology showed colocalization of Cy5.5 signal from RGD-Cy5.5-MN with CD34 in the lesions pointing to the targeted nature of the probe. This work offers initial proof-of-concept for targeting angiogenesis in endometriosis which can be useful for potential clinical diagnostic and therapeutic approaches for treating this disease.

Effects of SU5416 on angiogenesis and the ERK-VEGF/MMP-9 pathway in rat endometriosis.

SU5416 is a small molecule vascular endothelial growth factor (VEGF) receptor signal transduction inhibitor, which can block the VEGF re-ceptor autophosphorylation and inhibit receptor tyrosine kinase signal trans-duction, thereby reducing VEGF activity. However, there are few reports about the correlation of SU5416 to the occurrence and angiogenesis in endometrio-sis. In this study, we observed the effects of VEGF receptor inhibitor SU5416 on angiogenesis in endometriosis in rats. Thirty femalespecific-pathogen-free Sprague-Dawley rats were randomly divided into sham operation group (SOG), model group (MG), and SU5416 group (n=10 for each group). In the SOG, only the uterus was cut and sutured, and endometriosis models were established in the MG and SU5416 group by autologous transplantation. The SU5416 group was injected with 15 mg/kg SU5416 intraperitoneally, and the SOG and MG were intraperitoneally injected with an equal volume of normal saline for 6 weeks. The volume of ectopic lesions was lower in the SU5416 group at 42 d postoperatively thanin the MG (p&lt;0.05). The proportion of CD31-positive cells in the endometrial tissue of the SU5416 group was lower than that of the MG (p&lt;0.05); angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), laminin-5γ2 (LN-5γ2) and phosphorylation of ERK (P-ERK), VEGF, matrix metalloproteinase (MMP)-2, and MMP-9 protein expressions were lower in the SU5416 groupthan in the MG (p&lt;0.05).VEGFreceptor inhibitor SU5416 can inhibit endometrio-sis angiogenesis and reduce inflammatory response in rats, and its mechanism of action may be related to the down-regulation of the ERK-VEGF/MMP-9 path-way expression.

NLRP3 inflammasome-mediated Pyroptosis induce Notch signal activation in endometriosis angiogenesis

Endometriosis is characterized by the presence of endometrial tissue outside the uterus that not only causes severe pelvic pain and infertility but also increased risk for ovarian carcinogenesis in women of reproductive age. Here, we found that angiogenesis was increased and accompanied with up-regulation of Notch1 in human endometriotic tissue sample, which is associated with pyroptosis induced by activation of endothelial NLRP3 inflammasome. Further, in endometriosis model induced in wild type and NLRP3-deficient (NLRP3-KO) mice, we found that deficiency of NLRP3 suppressing the development of endometriosis. In vitro, inhibiting the activation of NLRP3 inflammasome prevents LPS/ATP-induced tube formation in endothelial cells. Meanwhile, knockdown NLRP3 expression by gRNA disrupt the interaction between Notch1 and HIF-1α under the inflammatory microenvironment. This study demonstrates that activation of NLRP3 inflammasome-mediated pyroptosis affects angiogenesis in endometriosis via Notch1-dependent manner.

The heterogeneity of fibrosis and angiogenesis in endometriosis revealed by single-cell RNA-sequencing

Fibrosis, angiogenesis and chronic inflammation are the inherent characteristics of endometriosis (EMS). The cellular heterogeneity of ectopic and non-ectopic endometrium by single-cell RNA-sequencing (scRNA-seq)at secretory phase without the disturbance of hormone drugs hasn't been explored so far. In this study, scRNA-seq was adopted to explore the properties of ectopic endometrium (ECE), eutopic endometrium (EUE) and normal endometrium (NOE) at secretory phase. We found that (i) The proportion of myofibroblasts, pericytes, endothelial cells and macrophages in ECE overwhelms that of non-ectopic tissues (EUE and NOE), and Myofibro.C2 was the predominant myofibroblast sub-cluster in ECE. (ii) Myofibroblasts were mainly fibroblast-to-myofibroblast transdifferentiation (FMT) and pericytes were endothelial cell-dependent differentiation in ECE. (iii) Both myofibroblasts and pericytes had a low differentiation potential. (iv) The increased inflammation score, deceased NK cells, T cell exhaustion score and antigen-presenting capacity in ECE confirmed the inflammatory properties and immunodeficiency of ECE. These findings suggested that myofibroblasts, pericytes and macrophages may be the potential targets for anti-fibrotic, anti-angiogenic and anti-inflammatory therapy of EMS.

Regulation of angiogenesis by microRNAs and long non-coding RNAs in endometriosis

Endometriosis (EM) is a benign gynecological disease that affects the fertility and health of women of reproductive age; it is characterized by the presence of endometrial glands and stroma outside the uterine cavity. Although several hypotheses have been proposed to explain the underlying cause of EM, its pathogenesis remains obscure. Recently, non-coding RNAs were reported to be involved in the occurrence and development of EM. MicroRNAs and long non-coding RNAs are the main members of the non-coding RNA family that contribute to EM progression in various aspects, such as cell proliferation, apoptosis, invasion, and angiogenesis. Angiogenesis plays a pivotal role in the initiation and development of EM and provides a substantial background for the invasion, proliferation, and long-term growth of endometriotic implants. This review aimed to investigate the role of microRNAs and long non-coding RNAs in regulating angiogenesis in EM and discuss how this mechanism can be used for diagnostic and therapeutic purposes in EM.

P-306 How ProEGCG achieves superior anti-angiogenic efficacy to prevent and treat endometriosis?

Abstract Study question What are the therapeutic targets and molecular mechanisms that bring superior pharmacological effects of ProEGCG against angiogenesis in endometriosis? Summary answer ProEGCG binds to PXK and downregulates PXK-mediated EGF expression in inhibiting angiogenesis via HIF-1α pathway during the growth and development of endometriosis. What is known already Current endometriosis treatment shows great effects in managing the symptoms, but associated with significant recurrence risk and hormonal side effects. Previously, we demonstrated the greater efficacies and potency of prodrug of green tea epigallocatechin gallate (ProEGCG) over EGCG to inhibit angiogenesis and oxidative stress in experimental endometriosis mouse models ( Xu, et al., 2011; Wang, et. al., 2013; Hung, et. al. 2021). However, the therapeutic targets and molecular mechanism to bring the superior anti-angiogenic effects of ProEGCG are still not known. Study design, size, duration Efficiency of ProEGCG as preventive or therapeutic medication were compared with that of EGCG in endometriosis mice model Therapeutic targets were studied by Proteome Integral Stability Alteration and proteomic analysis (Gaetani et al.,2019) using endometriotic cells, and further validated by computational simulation, target kinetic analysis and immunostaining. Anti-angiogenic mechanism were confirmed in endometriotic cell lines and mouse models. Participants/materials, setting, methods Endometriotic (Hs832(C)T) cell line was treated with EGCG or ProEGCG to identify the binding target with chemical proteomics analysis. The stability of ProEGCG-protein complexes was assessed by molecular docking analysis and bio-layer interferometry. Gene and protein expressions of the binding targets and downstream angiogenesis pathway were assessed by qRT-PCR, ELISA and immunostaining to characterise the molecular pathways in vitro and in vivo. Main results and the role of chance ProEGCG significantly reduced the endometriotic lesions in both preventive and treatment regimens with no recurrence risk after discontinuation in mice. MTDH and PXK were identified as differential protein targets of EGCG and ProEGCG respectively in Hs832(C)T cells via proteomics analysis. Molecular docking and kinetic studies validated stabilities of the drug-target complexes. Protein expressions of MTDH and PXK were significantly higher in various kinds of human endometriotic tissues compared with normal endometrium, which were found significantly downregulated in mouse endometriotic tissues after treatment of EGCG and ProEGCG, respectively. Angiogenesis was significantly inhibited by ProEGCG and EGCG in endometriosis in mice and downstream angiogenic factors HIF-1α and VEGF were downregulated in both mRNA and protein levels. However EGCG bound to MTDH and inhibited AKT-mediated angiogenesis via AKT/PI3K signalling pathway, while ProEGCG bound to PXK and inhibited EGF-mediated angiogenesis via more profound EGF/AKT1/HIF-1α/VEGF signalling pathways. It indicated distinct and specific potency of ProEGCG as an anti-proliferation and anti-angiogenesis agent in inhibiting the endometriosis progression. Limitations, reasons for caution The crosstalk of binding targets-induced therapeutic effects in endometriosis and their corresponding effects on angiogenesis are still unclear. Clinical studies are also needed to confirm the efficacy and mechanisms in humans. Wider implications of the findings Novel drug discovery identifies an ideal pharmaceutical for clinical use in endometriosis, which alleviates the symptoms, cures the disease and prevents the recurrence. Molecular targets and mechanisms as preclinical research priorities will optimize pharmacological and physiochemical properties of new drugs, as well as maximize specificity and efficacy for endometriosis treatment. Trial registration number NA

Exosomal lncRNA HOTAIR Promotes the Progression and Angiogenesis of Endometriosis via the miR-761/HDAC1 Axis and Activation of STAT3-Mediated Inflammation.

BackgroundLong non-coding RNA (lncRNA) and exosomes are implicated in endometriosis development. We measured the expression of an exosomal lncRNA, homeobox transcript antisense RNA (HOTAIR), and explored its molecular mechanism in endometriosis progression.MethodsExpression of HOTAIR and microRNA (miR)-761 in different endometrial tissues was measured. Exosomes were isolated from a culture medium of endometrial stromal cells (ESCs). RT-qPCR was used to measure HOTAIR expression in different exosome types. CCK-8, Edu, wound healing, transwell assays, flow cytometry and tube formation were used to detect the role of exosomal HOTAIR on ESCs and human umbilical vein endothelial cells (HUVECs). The relationship among miR-761, HOTAIR, and histone deacetylase 1 (HDAC1) was verified by dual-luciferase reporter assay. ESCs were transfected with miR-761 mimics or HDAC1 small interfering RNA (si-RNA) to ascertain if alterations in expression of miR-761 or HDAC1 could reverse the effect of exosomal HOTAIR. Then, we detected the effect of the HOTAIR/miR-761/HDAC1 axis on signal transducer and activator of transcription 3 (STAT3)-mediated inflammation. In vivo experiments were conducted to verify in vitro results.ResultsHOTAIR expression was upregulated and miR-761 expression was downregulated in ectopic endometrium tissues. HOTAIR was packaged into exosomes and transported from ESCs to surrounding cells. Exosomal HOTAIR promoted the proliferation, migration, and invasion, and inhibited the apoptosis of ESCs. Angiogenesis of HUVECs was enhanced after cultured with exosomal HOTAIR. HOTAIR acted as a competing endogenous RNA to downregulate miR-761 and increase HDAC1 expression. miR-761 overexpression or HDAC1 knockdown reversed the role of exosomal HOTAIR on ESCs and HUVECs. The HOTAIR/miR-761/HDAC1 axis could activate STAT3-related proinflammatory cytokines and stattic (inhibitor of phosphorylated-STAT3) could reverse the effect of HOTAIR on ESCs and HUVECs. In vivo experiments suggested that exosomal HOTAIR promoted the growth of endometrial lesions in vivo.ConclusionExosomal HOTAIR promoted the progression and angiogenesis of endometriosis by regulating the miR-761/HDAC1 axis and activating STAT3-mediated inflammation in vitro and in vivo, which may provide promising treatment for endometriosis.

Possible involvement of crosstalk between endometrial cells and mast cells in the development of endometriosis via CCL8/CCR1

BackgroundThe density and the activity of mast cells are associated with endometriosis. However, the role of mast cells on the pathogenesis of endometriosis remains unclear. Our study aims to investigate whether endometrial cells interact with mast cells and the involvement of their crosstalk in the development of endometriosis. MethodsThe transwell assay was applied to investigate the effect of mast cells on the migratory ability of human primary endometrial cells. Mast cells were cocultured with endometrial epithelial and stromal cells respectively and total RNAs were isolated and subjected to mRNA sequencing. Next, the transwell assay, CCK-8, and tube formation were applied to study the role of CCL8 on the endometrial and endothelial cells in vitro. The mouse model was also established to confirm the role of CCL8 in the development and angiogenesis of endometriosis. ResultsCCL8 was up-regulated in mast cells when cocultured with endometrial cells. CCL8 was highly expressed in the ectopic endometrium and the serum of patients with endometriosis. CCL8 promoted the migratory ability of endometrial epithelial and stromal cells and increased the proliferation, migration, and tube formation of endothelial cells. CCR1, the receptor of CCL8, was over-expressed in the ectopic endometrium and colocalized with blood vessels in ovarian endometriomas. The inhibition of CCR1 suppressed the development and angiogenesis of endometriosis in vivo. ConclusionThe crosstalk between endometrial cells and mast cells in the development of endometriosis via CCL8/CCR1 was demonstrated, thereby providing a new treatment strategy for endometriosis.

The Exosomal Long Noncoding RNA aHIF is Upregulated in Serum From Patients With Endometriosis and Promotes Angiogenesis in Endometriosis.

The transfer of long noncoding RNAs (lncRNAs) via exosomes to modulate recipient cells represents an important mechanism for disease progression. Antisense hypoxia-inducible factor (aHIF) is a well-known angiogenesis-related lncRNA. Here, we aimed to investigate the clinical implications of aHIF and exosomal aHIF in endometriosis and the involvement of exosome-shuttled aHIF in endometriosis angiogenesis. The distribution and expression of aHIF in ectopic, eutopic, and normal endometria was evaluated. Serum exosomal aHIF levels in patients with endometriosis were tested. The correlation between serum exosomal aHIF and aHIF expression in ectopic endometria was analyzed. Endometriotic cyst stromal cells (ECSCs)-derived exosomes were characterized. The internalization of exosomes by human umbilical vein endothelial cells (HUVECs) was observed. A series of in vitro assays were conducted to investigate the roles and mechanisms of exosomal aHIF in endometriosis angiogenesis. Clinically, aHIF was highly expressed in ectopic endometria and serum exosomes in patients with endometriosis. Serum exosomal aHIF was significantly correlated to aHIF expression in matched ectopic endometria. In vitro, PKH67-labeled exosomes derived from aHIF high expression ECSCs were effectively internalized by recipient HUVECs. Notably, exosome-shuttled aHIF was transferred from ECSCs to HUVECs, which in turn elicited proangiogenic behavior in HUVECs by activating vascular endothelial growth factor (VEGF)-A, VEGF-D, and basic fibroblast growth factor, thereby facilitating endometriosis angiogenesis. Our study illustrates a potential cell-cell communication between ECSCs and HUVECs in an ectopic environment, provides a novel mechanistic model explaining how ECSCs induce angiogenesis from the perspective of the "exosomal transfer of aHIF," and highlights the clinical value of circulating exosomal aHIF in endometriosis.

Suppression of COUP-TFII upregulates angiogenin and promotes angiogenesis in endometriosis.

How does hypoxia-mediated downregulation of chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII) promote angiogenesis in endometriosis? Suppression of COUP-TFII by hypoxia stimulates angiogenesis through induction of angiogenin (ANG). The level of COUP-TFII is downregulated in endometriotic tissues, and downregulation of COUP-TFII contributes to the development of endometriosis. Twenty-seven patients of reproductive age with endometriosis were recruited in this study. Eutopic endometrial and ectopic endometriotic stromal cells were isolated, cultured and subjected to various treatments. Microarray hybridization, quantitative RT-PCR, and Western blot were used to detect gene expression in normal and endometriotic samples. A luciferase reporter assay and chromatin immunoprecipitation in normoxia- or hypoxia-treated primary cultures of human endometrial stromal cells were performed. Tube formation analysis was performed using primary human umbilical vein endothelial cells (HUVECs). Protein level of COUP-TFII was downregulated by hypoxia (P < 0.05, normoxia versus hypoxia). Loss of COUP-TFII increased the angiogenic capacity of endometrial stromal cells (P < 0.05, COUP-TFII knockdown versus knockdown control). A novel COUP-TFII target gene, ANG, was identified through microarray analysis. Chromatin immunoprecipitation and promoter activity assays demonstrated that the ANG promoter was bound and suppressed by COUP-TFII (P < 0.05, COUP-TFII overexpression versus empty vector). The levels of ANG mRNA and protein were elevated in ectopic endometriotic stromal cells and negatively correlated with COUP-TFII (P < 0.05, endometrial versus endometriotic tissues/stromal cells). Both knockdown and forced-expression of COUP-TFII further demonstrated that ANG expression and ANG-mediated angiogenic activity were negatively regulated by COUP-TFII (P < 0.05, COUP-TFII knockdown versus knockdown control, and COUP-TFII overexpression versus empty vector). This study was conducted in primary human endometrial stromal cell cultures and HUVECs, therefore, may not fully reflect the situation in vivo. The raw data were submitted to Gene Expression Omnibus (GSE107469). This is the first study to highlight that the aberrant expression of ANG in endometriotic lesions is mediated by hypoxia-suppressed COUP-TFII expression, which reveals an as yet unidentified molecular pathogenesis of endometriosis. This work was supported by research grants (MOST 105-2314-B-006-059-MY3 to M.H.W. and MOST 104-2320-B-006-036-MY3 to S.J.T.) from the Ministry of Science and Technology, Taiwan. The authors declare that there is no conflict of interest.

Regulation of Matrix Metalloproteinase-2 Activity by COX-2-PGE2-pAKT Axis Promotes Angiogenesis in Endometriosis.

Endometriosis is characterized by the ectopic development of the endometrium which relies on angiogenesis. Although studies have identified the involvement of different matrix metalloproteinases (MMPs) in endometriosis, no study has yet investigated the role of MMP-2 in endometriosis-associated angiogenesis. The present study aims to understand the regulation of MMP-2 activity in endothelial cells and on angiogenesis during progression of ovarian endometriosis. Histological and biochemical data showed increased expressions of vascular endothelial growth factor (VEGF), VEGF receptor-2, cycloxygenase (COX)-2, von Willebrand factor along with angiogenesis during endometriosis progression. Women with endometriosis showed decreased MMP-2 activity in eutopic endometrium as compared to women without endometriosis. However, ectopic ovarian endometrioma showed significantly elevated MMP-2 activity with disease severity. In addition, increased MT1MMP and decreased tissue inhibitors of metalloproteinases (TIMP)-2 expressions were found in the late stages of endometriosis indicating more MMP-2 activation with disease progression. In vitro study using human endothelial cells showed that prostaglandin E2 (PGE2) significantly increased MMP-2 activity as well as tube formation. Inhibition of COX-2 and/or phosphorylated AKT suppressed MMP-2 activity and endothelial tube formation suggesting involvement of PGE2 in regulation of MMP-2 activity during angiogenesis. Moreover, specific inhibition of MMP-2 by chemical inhibitor significantly reduced cellular migration, invasion and tube formation. In ovo assay showed decreased angiogenic branching upon MMP-2 inhibition. Furthermore, a significant reduction of lesion numbers was observed upon inhibition of MMP-2 and COX-2 in mouse model of endometriosis. In conclusion, our study establishes the involvement of MMP-2 activity via COX-2-PGE2-pAKT axis in promoting angiogenesis during endometriosis progression.

Role of angiogenesis in endometriosis

Abstract Endometriosis is serious gynecological disease affecting millions of women world- wide. Despite long periods of intensive studies, the exact mechanisms are still unclear and no cure is in sight. Recently, the theory of

MicroRNAs and angiogenesis in endometriosis

miRNAs function as important regulators of a wide range of cellular processes, such as angiogenesis and fibrinolysis, by postranscriptional modulation of gene expression. We present a review on the role of miRNAs and angiogenesis in endometriosis. Endometriosis, defined as the implantation of endometrial tissue outside the uterine cavity, is one of the most frequent benign gynecological diseases and it has important consequences on the quality of life and fertility of patients. Similarly to tumor metastasis, the ectopic endometrium acquires the capability to adhere, proliferate and infiltrate the extracellular matrix. Endometriosis is a multifactorial and polygenic disease in which angiogenesis and proteolysis may be involved, and emerging data provide evidence that a dysregulation of miRNA expression may be implicated in these processes. The detection of circulating miRNAs in plasma and other body fluids and their relative stability has raised the possibility that they might serve as non-invasive biomarkers for the diagnosis of the disease. On the other hand, the development of therapies that might block the expression or mimic the functions of miRNAs could represent new therapeutic strategies for the treatment of endometriosis.

Inhibition of dual specificity phosphatase-2 by hypoxia promotes interleukin-8-mediated angiogenesis in endometriosis.

How does hypoxia-mediated down-regulation of dual specificity phosphatase-2 (DUSP2) promote endometriotic lesion development? Inhibition of DUSP2 by hypoxia enhances endometriotic lesion growth via promoting interleukin-8 (IL-8)-dependent angiogenesis. Angiogenesis is a prerequisite for the development of endometriosis. DUSP2 is down-regulated in endometriotic stromal cells in a hypoxia inducible factor-1α-dependent manner. Down-regulation of DUSP2 contributes to the pathological process of endometriosis. A laboratory study recruiting 20 patients of reproductive age with endometriosis and normal menstrual cycles, and an autoimplant-induced mouse model of endometriosis using 13 mice in a 28-day treatment. IL-8 mRNA levels were assayed in endometrial stromal cells maintained in normoxic or hypoxic (1% O2) conditions, with or without DUSP2 knockdown. Promoter activity and chromatin immunoprecipitation (ChIP) assays were conducted to characterize the regulation of IL-8 by DUSP2. Conditioned media from cells maintained in normoxic or hypoxic conditions, and cells with/without DUSP2 knockdown were collected to investigate the angiogenic capacity using an in vitro tube formation assay. Reparixin, an IL-8 receptor blocker, was administered to investigate the role of IL-8 in hypoxia-mediated angiogenesis and the development of endometriotic-like lesions in an autotransplanted mouse model. IL-8 mRNA was increased by both hypoxia and DUSP2 knockdown in endometrial stromal cells in an extracellular signal-regulated protein kinase-dependent manner (P < 0.05 versus control). Promoter activity and ChIP assays demonstrated that expression of IL-8 was regulated by CCAAT/enhancer binding protein α (P < 0.05 versus control). Furthermore, conditioned media collected from hypoxia-exposed or DUSP2 knockdown endometrial stromal cells promoted tube formation, which was abolished by co-treatment with reparixin (P < 0.05 versus control). Results from the autotransplanted mouse model demonstrated that number of blood vessels and size of endometriotic-like lesions were markedly reduced in recipient mice treated with reparixin (P < 0.05 versus control). This study was conducted in primary human cell cultures and a mouse model, therefore may not fully reflect the situation in vivo. This is the first study to highlight the potential application of an IL-8 receptor blocker as a therapeutic target to treat endometriosis. This study demonstrates IL-8 as a key angiogenic factor regulated by hypoxia/DUSP2, which suggests an alternative mechanism through which hypoxia may promote angiogenesis. This study was funded by the National Science Council of Taiwan (NSC101-2314-B-006-043-MY2). The author declares that there is no conflict of interest.

Effects of repeated propranolol administration in a rat model of surgically induced endometriosis

ObjectivesTo determine whether propranolol has an inhibitory effect on the angiogenesis of endometriosis in an experimental rat model or not. Study designThis was an experimental animal model study. Twenty-four female Wistar albino rats (200–250g) were used to create a model for surgical induction of endometriosis. Two rats died during the surgeries. The rats were randomly divided into treatment (n=11) and control groups (n=10), which were treated with daily intraperitoneal propranolol (10mg/kg) and saline (2mL), respectively. Study duration was 8 weeks. The volumes and histopathological findings of the implants, and immunochemistry for vascular endothelial growth factor (VEGF), metalloproteinase (MMP)-2, and MMP-9 were evaluated. ResultsViable endometriotic implants were created in all animals. In the propranolol-treated group, the mean implant volume significantly decreased after treatment (142.5 vs. 32.1mm3, respectively; p=0.008), while the mean implant volume significantly increased in the control group (141.0 vs. 174.2mm3, respectively; p=0.009). There were also significant reductions in VEGF immunoreactivity scores and both stroma and epithelium MMP-2 and MMP-9 immunoreactivity scores in the propranolol-treated group compared with the control group (p<0.005 for all scores). ConclusionsPropranolol may suppress endometrial tissue by its antiangiogenic activity through inhibitory actions on VEGF, MMP-2, and MMP-9. Therefore, propranolol is a promising candidate drug for effective treatment of patients with endometriosis, which needs to be confirmed with further studies.

Effect of oxygen tensions on the proliferation and angiogenesis of endometriosis heterograft in severe combined immunodeficiency mice

To investigate the effects of oxygen on the proliferation and angiogenesis of endometriosis in vivo. Animal studies. Animal research facility. Thirty-six female severe combined immunodeficiency (SCID) mice, implanted with eutopic endometrium from seven endometriosis patients. Human eutopic endometrial tissues were randomized to normoxia, hyperoxia, or hypoxia pretreatment and were subcutaneously implanted into estrogen-treated ovariectomized SCID mice. The growth and quality of the implants were measured, and the expression of proliferation- and angiogenesis-associated markers (i.e., Ki67, CD31, vascular endothelial growth factor, and hypoxia-inducible factor-1α) were assessed using immunohistochemistry and Western blot analyses. The growth curves of the implants were distinct with different oxygen pretreatments. The growth of the implants of the hypoxia group was significantly increased compared with the normoxia group, but the growth of the implants of the hyperoxia group was significantly decreased compared with the normoxia group. Microscopic examination indicated that lesions with hyperplastic cylindrical glandular epithelium were surrounded by the endometrial stroma in the hypoxia group, but the glandular epithelium was partially depauperate in the hyperoxia group. The expression of Ki67, CD31, vascular endothelial growth factor, and hypoxia-inducible factor-1α in the hypoxia-pretreated implants was significantly higher compared with the hyperoxia or normoxia groups. Oxygen can alter the growth patterns of endometriosis implants in a SCID mouse model. Hypoxia pretreatment promoted the proliferation and angiogenesis of endometriosis, whereas hyperoxia pretreatment exhibited the opposite effect.

Slit2 Overexpression Results in Increased Microvessel Density and Lesion Size in Mice With Induced Endometriosis

We recently reported that Slit/Roundabout (ROBO) 1 pathway may be a constituent biomarker for recurrence of endometriosis, likely through promoting angiogenesis. In this study, we sought to determine as whether Slit2 overexpression can facilitate angiogenesis, increase lesion size, and induce hyperalgesia in mice with induced endometriosis. We used 30 Slit2 transgenic (S) and 29 wild-type (W) mice and cross-transplanted endometrial fragments from S to W (group SW) and vice versa (group WS), and also within the S and W (groups SS and WW, respectively), into the peritoneal cavity, inducing endometriosis. We also performed a sham surgery within both S and W mice (groups Sm and Wm, respectively). The size of the ectopic implants, microvessel density (MVD) and immunoreactivity to ROBO1, and vascular endothelial cell growth factor (VEGF) in ectopic and eutopic endometrium, along with hotplate and tail-flick tests in all mice, were then evaluated. We found that the induction of endometriosis resulted in generalized hyperalgesia, which was unaffected by Slit2 overexpression. Slit2 overexpression did increase the lesion size significantly and correlated positively with the MVD in ectopic and eutopic endometrium. Slit2 expression levels appear to correlate with the MVD, but not with VEGF immunoreactivity, in ectopic endometrium. Consequently, we conclude that Slit2 may play an important role in angiogenesis in endometriosis. The increased angiogenesis, as measured by MVD, but not VEGF immunoreactivity, likely resulted in increased lesion size in induced endometriosis. Thus, SLIT2/ROBO1 pathway may be a potential therapeutic target for treating endometriosis.