Endometriosis is an estrogen-dependent benign gynecological disease that shares some common features of malignancy. Epithelial–mesenchymal transition (EMT) has been recognized as a core mechanism of endometriosis. MALAT1 is widely known as EMT promoter, while miR200 family members (miR200s) are considered as EMT inhibitors. Previous studies have reported that MALAT1 upregulation and miR200s downregulation are observed in endometriosis. MiR200c has been regarded as the strongest member of miR200s to interact with MALAT1. However, whether MALAT1/miR200c regulates EMT remains largely unclear. In this study, the roles of miR200s and MALAT1 in ectopic endometrium were investigated. Additionally, the effects of E2 on EMT and MALAT1/miR200s were examined in both EECs and Ishikawa cells. Notably, E2 could upregulate MALAT1 and downregulate miR200s expression levels and induce EMT in EECs and Ishikawa cells. PHTPP, an ERβ antagonist, could reverse the effect of E2. Overexpression of miR200c and knockdown of MALAT1 significantly inhibited E2-mediated EMT, suggesting that both miR200c and MALAT1 are involved in the E2-induced EMT process in endometriosis. In addition, a reciprocal inhibition was found between miR200s and MALAT1. Therefore, the role of MALAT1/miR200c in EMT is influenced by the presence of estrogen during endometriosis development.
Yu Du, Zhibing Zhang, Wenqian Xiong, Na Li, Hengwei Liu, Haitang He, Qi Li, Yi Liu and Ling Zhang
Hengwei Liu, Zhibing Zhang, Wenqian Xiong, Ling Zhang, Yao Xiong, Na Li, Haitang He, Yu Du and Yi Liu
Endometriosis is a benign gynecological disease that shares some characteristics with malignancy like migration and invasion. It has been reported that both hypoxia-inducible factor-1α (HIF-1α) and autophagy were upregulated in ectopic endometrium of patients with ovarian endometriosis. However, the crosstalk between HIF-1α and autophagy in the pathogenesis of endometriosis remains to be clarified. Accordingly, we investigated whether autophagy was regulated by HIF-1α, as well as whether the effect of HIF-1α on cell migration and invasion is mediated through autophagy upregulation. Here, we found that ectopic endometrium from patients with endometriosis highly expressed HIF-1α and autophagy-related protein LC3. In cultured human endometrial stromal cells (HESCs), autophagy was induced by hypoxia in a time-dependent manner and autophagy activation was dependent on HIF-1α. In addition, migration and invasion ability of HESCs were enhanced by hypoxia treatment, whereas knockdown of HIF-1α attenuated this effect. Furthermore, inhibiting autophagy with specific inhibitors and Beclin1 siRNA attenuated hypoxia triggered migration and invasion of HESCs. Taken together, these results suggest that HIF-1α promotes HESCs invasion and metastasis by upregulating autophagy. Thus, autophagy may be involved in the pathogenesis of endometriosis and inhibition of autophagy might be a novel therapeutic approach to the treatment of endometriosis.
Mei-rong Zhao, Wei Qiu, Yu-xia Li, Zhi-bin Zhang, Dong Li and Yan-ling Wang
Transforming growth factor β (TGFβ) has been shown to be a multifunctional cytokine required for embryonic development and regulation of trophoblast cell behaviors. In the present study, a non-transformed cell-line representative of normal human trophoblast (NPC) was used to examine the effect of TGFβ1 on trophoblast cell adhesion and invasion. In vitro assay showed that TGFβ1 could significantly promote intercellular adhesion, while inhibiting cell invasion across the collagen I-coated filter. Reverse transcription (RT)-PCR and gelatin zymography demonstrated that TGFβ1 evidently repressed the mRNA expression and proenzyme production of matrix metalloproteinase (MMP)-9, but exerted no effect on mRNA expression and secretion of MMP-2. On the other hand, both the mRNA and protein expression of epithelial-cadherin and β-catenin were obviously upregulated by TGFβ1 in dose-dependent fashion, as revealed by RT-PCR and western-blot analysis. What is more, one of the critical TGFβ signaling molecules – Smad2 was notably phosphorylated in TGFβ1-treated NPC cells. The data indicates that cell invasion and adhesion are coordinated processes in human trophoblasts and that there exists paracrine regulation on adhesion molecules and invasion-associated enzymes in human placenta.
Keqin Yan, Dingqing Feng, Jing Liang, Qing Wang, Lin Deng, Xiao Zhang, Bin Ling and Daishu Han
Viral infections of the ovary may perturb ovarian functions. However, the mechanisms underlying innate immune responses in the ovary are poorly understood. The present study demonstrates that cytosolic viral DNA sensor signaling initiates the innate immune response in mouse ovarian granulosa cells and affects endocrine function. The cytosolic DNA sensors p204 and cGAS and their common signaling adaptor stimulator of interferon (IFN) genes (STING) were constitutively expressed in granulosa cells. Transfection with VACV70, a synthetic vaccinia virus (VACV) DNA analog, induced the expression of type I interferons (IFNA/B) and major inflammatory cytokines (TNFA and IL6) through IRF3 and NF-κB activation respectively. Moreover, several IFN-inducible antiviral proteins, including 2′,5′-oligoadenylate synthetase, IFN-stimulating gene 15 and Mx GTPase 1, were also induced by VACV70 transfection. The innate immune responses in granulosa cells were significantly reduced by the transfection of specific small-interfering RNAs targeting p204, cGas or Sting. Notably, the VACV70-triggered innate immune responses affected steroidogenesis in vivo and in vitro. The data presented in this study describe the mechanism underlying ovarian immune responses to viral infection.
Xin Yuan, Jianlin Du, Qin Qin, Xiaoqun Li, Songbai Deng, Yunqing Chen, Ling Zhang and Qiang She
Genetic lineage tracing has been used extensively in developmental biology. Many transcription factors expressed in sperm may induce Cre-mediated loxP recombination during early zygote development. In this study, we investigated the effect of sperm-expressed Cre on cell type-specific Cre-mediated loxP recombination in fate-mapping models of Tbx18+ progenitor cells. We found the recombination frequency in a reverse mating (RM) lineage was inconsistent with a normal Mendelian distribution. However, the recombination frequency in a positive mating (PM) lineage agreed with a Mendelian distribution. In the PM lineage, LacZ and EYFP were expressed in specific locations, such as the limb buds, heart, and hair follicles. Therefore, the reporter genes accurately and reliably traced cell differentiation in the PM lineage. In contrast, EYFP and LacZ were expressed throughout the embryo in the RM lineage. Thus, the reporter genes did not trace cell differentiation specifically in the RM lineage. Furthermore, Tbx18 mRNA and protein were expressed in the testicles of male mice, but almost no Tbx18 expression was detected in the ovaries of female mice. Similarly, reporter genes and Tbx18 were coexpressed in the seminiferous tubules and sperm cells of testicles. These results revealed that Cre-loxP-mediated pre-recombination in zygotes is due to Tbx18 expressed in testicle sperm cells when Cre is transmitted paternally. Our results indicate that Cre-mediated specific recombination in fate-mapping models of sperm-expressed genes may be influenced by the paternal origin of Cre. Therefore, a careful experimental design is critical when using the Cre-loxP system to trace spatial, temporal or tissue-specific fates.
Wenqian Xiong, Ling Zhang, Lan Yu, Wei Xie, Yicun Man, Yao Xiong, Hengwei Liu and Yi Liu
Endometriosis is an estrogen-dependent disease that involves the adhesion, invasion, and angiogenesis of endometrial tissues outside of the uterine cavity. We hypothesized that a link exists between estrogen and beta-catenin (β-catenin) signaling in the pathogenesis of endometriosis. Human endometrial stromal cells (HESCs) were separated from eutopic endometrial tissues that were obtained from patients with endometriosis. β-catenin expression and cells invasiveness ability were up-regulated by 17β-estradiol (E2) in an estrogen receptor (ESR)-dependent manner, whereas β-catenin siRNA abrogated this phenomenon. Moreover, co-immunoprecipitation and dual immunofluorescence studies confirmed ESR1, β-catenin, and lymphoid enhancer factor 1/T cell factor 3 co-localization in the nucleus in HESCs after E2 treatment. To determine the role of β-catenin signaling in the implantation of ectopic endometrium, we xenotransplanted eutopic endometrium from endometriosis patients into ovariectomized severe combined immunodeficiency mice. The implantation of the endometrium was suppressed by β-catenin siRNA. Collectively, studies regarding β-catenin signaling are critical for improving our understanding of the pathogenesis of estrogen-induced endometriosis, which can translate into the development of treatments and therapeutic strategies for endometriosis.
Na Li, Ling Zhang, Qi Li, Yu Du, Hengwei Liu, Yi Liu and Wenqian Xiong
Oestrogen has been reported to control the invasiveness of endometrial stromal cells in endometriosis. Notch signalling, a master regulator of cell invasion in tumours, is regulated by oestrogen in other diseases and hyperactivated in endometriotic stromal cells. Therefore, we hypothesized that an interaction between Notch signalling and oestrogen may exist in the regulation of endometrial stromal cell invasion, which is essential for the development of endometriosis. Western blot analysis of tissues showed that the expression levels of Notch components (JAG1 and NOTCH1) and Notch activity were markedly higher in ectopic endometria than in their eutopic and normal counterparts. Primary stromal cells obtained from normal endometria cultured with oestrogen presented significant increases in the expression of Notch components and Notch activity, the cytoplasmic and nuclear accumulation of NOTCH1 intracellular domain, the expression of matrix metallopeptidase 9 and vascular endothelial growth factor and cell invasiveness. Knockdown of NOTCH1 markedly alleviated oestrogen-induced matrix metallopeptidase 9 and vascular endothelial growth factor expression and cell invasion. ICI (an oestrogen receptor antagonist) also blocked these oestrogenic effects. Oestrogen-responsive elements were found in the promoters of NOTCH1 and JAG1. A luciferase reporter analysis revealed that oestrogen regulated the expression of Notch components via oestrogen receptor alpha, which bound to oestrogen-responsive elements in the JAG1 and NOTCH1 promoters. Collectively, our findings indicate that oestrogen engages in crosstalk with Notch signalling to regulate cell invasion in endometriosis via the activation of oestrogen receptor alpha and the enhancement of Notch activity. Notch signalling blockade may therefore be a novel therapeutic target for endometriosis.
Ma Tian-Zhong, Chen Bi, Zhang Ying, Jing Xia, Peng Cai-Ling, Zhang Yun-Shan, Huang Mei-Wen and Niu Yan-Ru
Emx2 deletion impairs the growth and maintenance of the genital ridge. However, its role in subsequent germ cell differentiation during embryonic stages is unknown. Using a tamoxifen-inducible Cre-loxP mouse model (Emx2 flox/flox, Cre-ER TM, hereafter called as Emx2 knockdown), we showed that germ cell differentiation was impaired in Emx2-knockdown testes. Representative characteristics of male germ cell differentiation, including a reduced ability to form embryonic germ (EG) cell colonies in vitro, down-regulation of pluripotency markers and G1/G0 arrest, did not occur in Emx2-knockdown testes. Furthermore, FGF9 and NODAL signalling occurred at abnormally high levels in Emx2-knockdown testes. Both blocking FGF9 signalling with SU5402 and inhibiting NODAL signalling with SB431542 allowed germ cells from Emx2-knockdown testes to differentiate in vitro. Therefore, EMX2 in somatic cells is required to trigger germ cell differentiation in XY foetuses, posterior to its previously reported role in the growth and maintenance of the genital ridge.
Xiao-Qian Meng, Ke-Gang Zheng, Yong Yang, Man-Xi Jiang, Yan-Ling Zhang, Qing-Yuan Sun and Yun-Long Li
Microfilaments (actin filaments) regulate various dynamic events during meiotic maturation. Relatively, little is known about the regulation of microfilament organization in mammalian oocytes. Proline-rich tyrosine kinase2 (Pyk2), a protein tyrosine kinase related to focal adhesion kinase (FAK) is essential in actin filaments organization. The present study was to examine the expression and localization of Pyk2, and in particular, its function during rat oocyte maturation. For the first time, by using Western blot and confocal laser scanning microscopy, we detected the expression of Pyk2 in rat oocytes and found that Pyk2 and Try402 phospho-Pyk2 were localized uniformly at the cell cortex and surrounded the germinal vesicle (GV) or the condensed chromosomes at the GV stage or after GV breakdown. At the metaphase and the beginning of anaphase, Pyk2 distributed asymmetrically both in the ooplasm and the cortex with a marked staining associated with the chromosomes and the region overlying the meiotic spindle. At telophase, Pyk2 was observed in the cleavage furrows in addition to its cortex and cytoplasm localization. The dynamics of Pyk2 were similar to that of F-actin, and this kinase was found to co-localize with microfilaments in several developmental stages during rat oocyte maturation. Microinjection of Pyk2 antibody demolished the microfilaments assembly and also inhibited the first polar body (PB1) emission. These findings suggest an important role of Pyk2 for rat oocyte maturation by regulating the organization of actin filaments.
Xiao Sun, Ye Chun Ruan, Jinghui Guo, Hui Chen, Lai Ling Tsang, Xiaohu Zhang, Xiaohua Jiang and Hsiao Chang Chan
In our previous study, we have demonstrated that the epithelial sodium channel (ENaC) mediates the embryo-derived signals leading to the activation of CREB and upregulation of cyclooxygenase type 2 (COX2) required for embryo implantation. This study aims to investigate whether microRNAs (miRNAs) are involved in the ENaC-induced upregulation of COX2 during embryo implantation. The results show that the levels of miR-101 and miR-199a-3p, two COX2 targeting miRNAs, are reduced by ENaC activation, and increased by ENaC inhibition or knock-down of ENaC subunit (ENaCα) in human endometrial surface epithelial (HES) cells or in mouse uteri during implantation. Phosphorylation of CREB is induced by the activation of ENaC, and blocked by ENaC inhibition or knockdown in HES cells. Knockdown of ENaCα or CREB in HES cells or in mouse uterus in vivo results in increases in miR-101 and miR-199a-3p, accompanied with decreases in COX2 protein levels and reduction in implantation rate. The downregulation of COX2 caused by knockdown of ENaC or CREB can be recovered by the inhibitors of miR-101 or miR-199a-3p in HES cells. These results reveal a novel molecular mechanism modulating COX2 expression during embryo implantation via ENaC-dependent CREB activation and COX2-targeting miRNAs.