Manipulating actin dynamics affects human in vitro decidualization

Primary cilia prevent activation of the cGAS-STING pathway during mouse decidualization

Primary cilia are antenna-like organelles that sense extracellular signals and function as signaling hubs essential for vertebrate development and homeostasis. Decidualization is crucial for pregnancy establishment and maintenance in both humans and mice. While primary cilia are present in endometrial stromal cells, their role in pregnancy remains unknown. Here, we identify TMEM67, a key component of the ciliary transition zone, as a critical regulator of mouse decidualization. Loss of primary cilia triggers RhoA-MLC2-dependent actomyosin contraction, which transmits mechanical forces to the nuclear lamina, leading to micronuclei formation. Within these micronuclei, double-stranded DNA (dsDNA) can directly bind to cyclic GMP-AMP synthase (cGAS) in situ, initiating downstream signaling. This activation of the cGAS-STING pathway reduces CCL6 production and impairs decidualization. Furthermore, pharmacological inhibition of actin polymerization or RhoA-ROCK signaling alleviates mechanical forces surrounding stromal cells, restores ciliogenesis, maintains nuclear integrity, suppresses the cGAS-STING pathway activation, and ultimately rescues decidualization. Our findings reveal a previously unrecognized mechanism by which primary cilia regulate the actin cytoskeleton to maintain nuclear integrity and prevent DNA leakage. This safeguards against aberrant activation of the cGAS-STING pathway, which would otherwise trigger detrimental immune signaling and impair decidualization.

PAI-1 promotes human endometrial stromal decidualization via inhibiting VEGFR2/PI3K/AKT signaling pathway mediated F-actin reorganization

Decidualization of endometrial stromal cells is a prerequisite for successful embryo implantation and early pregnancy. Decidualization dysregulation results in implantation failure. In our previous study, we reported that PAI-1 is abnormally downregulated in the endometrial tissue samples of patients with recurrent implantation failure. This study will explore the dynamic expression changes of PAI-1 in the endometrium during the menstrual cycle and its molecular mechanism affecting endometrial decidualization. Our findings indicated that the abundance of PAI-1 increased in the mid-secretory phase and attached a peak in the decidual phase in the endometrium of women with regular menstrual cycles. In human endometrial stromal cells (HESCs), PAI-1 knockdown attenuated endometrial decidualization by upregulating VEGFR2/PI3K/AKT signaling pathway and impaired the F-actin reorganization. Furthermore, axitinib (a VEGFR2 inhibitor) was used to inhibit the VEGFR2 protein activity and the results suggested that it eliminated the effects of PAI-1 on PI3K/AKT signaling pathways and F-actin remodeling. In addition, the interaction between PAI-1 and KNG1 was confirmed by coimmunoprecipitation assay in HESCs. Altogether, PAI-1-KNG1 may enhance the decidualization of endometrium by inhibiting VEGFR2/PI3K/AKT signaling pathway-mediated F-actin reorganization in healthy females.

Overexpression of USP22 ameliorates LPS-induced endometrial stromal cells inflammation and modulates cells decidualization by inhibiting ferroptosis

Endometritis and the failure of decidualization of the endometrium are important factors contributing to the increased incidence of abortion. USP22 is associated with various inflammatory diseases and has been shown to be involved in endometrial decidualization in mice. This study aims to investigate whether USP22 is involved in the regulation of inflammatory response and decidualization in human endometrial stromal cells (hESCs). In this study, lipopolysaccharide (LPS) was used to induce inflammation in hESCs, and MPA combined with cAMP was used to induce decidualization of hESCs. USP22 overexpression vector was constructed to study the role of USP22 in endometritis. The results showed that the USP22 protein and mRNA levels were decreased in LPS-induced hESCs. LPS induction increased the levels of TNF-α, IL-1β, and IL-6, as well as the expression of iNOS and COX2 proteins in hESCs. In the LPS group, the levels of F-actin, PRL, IGFBP1, SLC7A11, and GPX4 proteins decreased, while the levels of lipid peroxidation and total iron content increased. Additionally, the levels of ACSL4 and TFR1 proteins were up-regulated. Overexpression of USP22 reversed LPS-induced cellular inflammation, attenuated decidualization, and inhibited ferroptosis. However, the use of ferroptosis inducers diminished the regulatory effects of USP22 on inflammatory responses and decidualization. In summary, these suggested that USP22 reduces the LPS-induced inflammatory response and regulates the decidualization of hESCs, and possibly involving ferroptosis.

Nuclear actin assembly is an integral part of decidualization in human endometrial stromal cells

Decidualization of the human endometrium is critical for establishing pregnancy and is entailed by differentiation of endometrial stromal cells (ESCs) into decidual cells. During decidualization, the actin cytoskeleton is dynamically reorganized for the ESCs' morphological and functional changes. Although actin dynamically alters its polymerized state upon external stimuli not only in the cytoplasm, but also in the nucleus, nuclear actin dynamics during decidualization have not been elucidated. Here, we show that nuclear actin was specifically assembled during decidualization of human ESCs. This decidualization-specific formation of nuclear actin filaments was disassembled following the withdrawal of the decidualization stimulus, suggesting its reversible process. Mechanistically, RNA-seq analyses revealed that the forced disassembly of nuclear actin resulted in the suppression of decidualization, accompanied with the abnormal upregulation of cell proliferation genes, leading to incomplete cell cycle arrest. CCAAT/enhancer-binding protein beta (C/EBPβ), an important regulator for decidualization, was responsible for downregulation of the nuclear actin exporter, thus accelerating nuclear actin accumulation and its assembly for decidualization. Taken together, we demonstrate that decidualization-specific nuclear actin assembly induces cell cycle arrest for establishing the decidualized state of ESCs. We propose that not only the cytoplasmic actin, but also nuclear actin dynamics profoundly affect decidualization process in humans for ensuring pregnancy.

ATOH8 Expression Is Regulated by BMP2 and Plays a Key Role in Human Endometrial Stromal Cell Decidualization

During the secretory phase of the menstrual cycle, elongated fibroblast-like mesenchymal cells in the uterine endometrium begin to transdifferentiate into polygonal epithelioid-like (decidual) cells. This decidualization process continues more broadly during early pregnancy, and the resulting decidual tissue supports successful embryo implantation and placental development. This study was carried out to determine if atonal basic helix-loop-helix transcription factor 8 (ATOH8) plays a role in human endometrial stromal fibroblast (ESF) decidualization. ATOH8 messenger RNA and protein expression levels significantly increased in human ESF cells undergoing in vitro decidualization, with the protein primarily localized to the nucleus. When ATOH8 expression was silenced, the ability of the cells to undergo decidualization was significantly diminished. Overexpression of ATOH8 enhanced the expression of many decidualization markers. Silencing the expression of ATOH8 reduced the expression of FZD4, FOXO1, and several known FOXO1-downstream targets during human ESF cell decidualization. Therefore, ATOH8 may be a major upstream regulator of the WNT/FZD-FOXO1 pathway, previously shown to be critical for human endometrial decidualization. Finally, we explored possible regulators of ATOH8 expression during human ESF decidualization. BMP2 significantly enhanced ATOH8 expression when cells were stimulated to undergo decidualization, while an ALK2/3 inhibitor reduced ATOH8 expression. Finally, although the steroids progesterone plus estradiol did not affect ATOH8 expression, the addition of cyclic adenosine monophosphate (cAMP) analogue alone represented the major effect of ATOH8 expression when cells were stimulated to undergo decidualization. Our results suggest that ATOH8 plays a crucial role in human ESF decidualization and that BMP2 plus cAMP are major regulators of ATOH8 expression.

β-Lactoglobulin affects the oxidative status and viability of equine endometrial progenitor cells via lncRNA-mRNA-miRNA regulatory associations

The β-lactoglobulin (β-LG) was previously characterized as a mild antioxidant modulating cell viability. However, its biological action regarding endometrial stromal cell cytophysiology and function has never been considered. In this study, we investigated the influence of β-LG on the cellular status of equine endometrial progenitor cells under oxidative stress. The study showed that β-LG decreased the intracellular accumulation of reactive oxygen species, simultaneously ameliorating cell viability and exerting an anti-apoptotic effect. However, at the transcriptional level, the reduced mRNA expression of pro-apoptotic factors (i.e. BAX and BAD) was accompanied by decreased expression of mRNA for anti-apoptotic BCL-2 and genes coding antioxidant enzymes (CAT, SOD-1, GPx). Still, we have also noted the positive effect of β-LG on the expression profile of transcripts involved in endometrial viability and receptivity, including ITGB1, ENPP3, TUNAR and miR-19b-3p. Finally, the expression of master factors of endometrial decidualization, namely prolactin and IGFBP1, was increased in response to β-LG, while non-coding RNAs (ncRNAs), that is lncRNA MALAT1 and miR-200b-3p, were upregulated. Our findings indicate a novel potential role of β-LG as a molecule regulating endometrial tissue functionality, promoting viability and normalizing the oxidative status of endometrial progenitor cells. The possible mechanism of β-LG action includes the activation of ncRNAs essential for tissue regeneration, such as lncRNA MALAT-1/TUNAR and miR-19b-3p/miR-200b-3p.

Immune Tolerance of Embryo Implantation and Pregnancy: The Role of Human Decidual Stromal Cell- and Embryonic-Derived Extracellular Vesicles

Embryo–endometrial communication plays a critical role in embryo implantation and the establishment of a successful pregnancy. Successful pregnancy outcomes involve maternal immune modulation during embryo implantation. The endometrium is usually primed and immunomodulated by steroid hormones and embryo signals for subsequent embryo implantation and the maintenance of pregnancy. The roles of extracellular vesicles (EVs) and microRNAs for the embryo–maternal interactions have been elucidated recently. New evidence shows that endometrial EVs and trophectoderm-originated EV cargo, including microRNAs, proteins, and lipids in the physiological microenvironment, regulate maternal immunomodulation for embryo implantation and subsequent pregnancy. On the other hand, trophoblast-derived EVs also control the cross-communication between the trophoblasts and immune cells. The exploration of EV functions and mechanisms in the processes of embryo implantation and pregnancy will shed light on a practical tool for the diagnostic or therapeutic approaches to reproductive medicine and infertility.

TOP2A deficit-induced abnormal decidualization leads to recurrent implantation failure via the NF-κB signaling pathway

BACKGROUND

Successful implantation is a complex process that is influenced by embryo quality, endometrial receptivity, immune factors, and the specific type of in vitro fertilization protocol used. DNA topoisomerase IIα (TOP2A) is a well-known protein involved in cell proliferation; however, its expression and effect on the endometrium in recurrent implantation failure (RIF) have not been fully elucidated.

METHODS

The human endometrial tissues of healthy controls and patients with RIF were collected. A proteomic analysis was performed to evaluate the differentially expressed proteins between the RIF group and the fertile control group. The expression patterns of TOP2A in the human preimplantation endometrium of the patients with RIF were determined by immunohistochemical staining, Western blotting and qRT-PCR. TOP2A knockdown (sh-TOP2A) T-HESCs were generated using lentiviruses. The expression of TOP2A in T-HESCs was manipulated to investigate its role in decidualization. The TOP2A-related changes in decidualization were screened by mRNA sequencing in decidualized TOP2A knockdown and control T-HESCs and then confirmed by Western blotting and immunofluorescence staining. TOP2A-deficient mice were generated by injection of TOP2A-interfering adenovirus on GD2.5 and GD3.5.

RESULTS

We performed a proteomic analysis of endometrial tissues to investigate the potential pathogenesis of RIF by comparing the patients with RIF and the matched controls and found that TOP2A might be a key protein in RIF. TOP2A is ubiquitously expressed in both stromal and glandular epithelial cells of the endometrium. The data indicate that TOP2A expression is significantly lower in the mid-secretory endometrium of women with RIF. TOP2A expression was downregulated under stimulation by 8-bromo-cAMP and MPA. Ablation of TOP2A resulted in upregulated expression of decidual biomarkers and morphological changes in the cells. Mechanistic analysis revealed that TOP2A regulates the NF-κB signaling pathway in decidualized T-HESCs. The TOP2A-deficient mice exhibited lower fetal weights.

CONCLUSIONS

Our findings revealed that abnormal expression of TOP2A affects decidualization and changes the "window of implantation", leading to RIF. TOP2A participates in the processes of decidualization and embryo implantation, functioning at least in part through the NF-κB pathway. Regulating the expression of TOP2A in the endometrium may become a new strategy for the prevention and treatment of RIF.

Nuclear receptor coactivator-6 is essential for the morphological change of human uterine stromal cell decidualization via regulating actin fiber reorganization

Nuclear receptor coactivator 6 (Ncoa6), a modulator of several nuclear receptors and transcription factors, is essential for the decidualization of endometrial stromal cells in mice. However, the function of Ncoa6 in the human endometrium remains unclear. We investigated its function in the decidualization of human endometrial stromal cells (HESCs) isolated from resected uteri. Knockdown of Ncoa6 was performed using two independent small interfering RNAs. Decidualization was induced in vitro via medroxyprogesterone and cyclic adenosine monophosphate. We compared decidualized cellular morphology between the Ncoa6 knockdown cells and control cells. Messenger RNA (mRNA) sequencing was performed to determine the Ncoa6 target genes in undecidualized HESCs. We found that the knockdown of Ncoa6 caused the failure of morphological changes in decidualized HESCs compared to that in the control cells. mRNA sequencing revealed that Ncoa6 regulates the expression of genes associated with the regulation of actin fibers. Ncoa6 knockdown cells failed to reorganize actin fibers during the decidualization of HESCs. Ncoa6 was shown to play an essential role in decidualization via the appropriate regulation of actin fiber regulation in HESCs. Herein, our in vitro studies revealed a part of the mechanisms involved in endometrial decidualization. Future research is needed to investigate these mechanisms in women with implantation defects.

Progesterone triggers Rho kinase-cofilin axis during in vitro and in vivo endometrial decidualization

STUDY QUESTION

Can a combination of the focussed protein kinase assays and a wide-scale proteomic screen pinpoint novel, clinically relevant players in decidualization in vitro and in vivo?

SUMMARY ANSWER

Rho-dependent protein kinase (ROCK) activity is elevated in response to the combined treatment with progesterone and 8-Br-cAMP during in vitro decidualization, mirrored by increase of ROCK2 mRNA and protein levels and the phosphorylation levels of its downstream target Cofilin-1 (CFL1) in secretory versus proliferative endometrium.

WHAT IS KNOWN ALREADY

Decidualization is associated with extensive changes in gene expression profile, proliferation, metabolism and morphology of endometrium, yet only a few underlying molecular pathways have been systematically explored. In vitro decidualization of endometrial stromal cells (ESCs) can be reportedly induced using multiple protocols with variable physiological relevance. In our previous studies, cyclic AMP (cAMP)/cAMP-dependent protein kinase (PKA)/prolactin axis that is classically upregulated during decidualization showed dampened activation in ESCs isolated from polycystic ovary syndrome (PCOS) patients as compared to controls.

STUDY DESIGN, SIZE, DURATION

In vitro decidualization studies were carried out in passage 2 ESCs isolated from controls (N = 15) and PCOS patients (N = 9). In parallel, lysates of non-cultured ESCs isolated from proliferative (N = 4) or secretory (N = 4) endometrial tissue were explored. The observed trends were confirmed using cryo-cut samples of proliferative (N = 3) or secretory endometrium (N = 3), and in proliferative or secretory full tissue samples from controls (N = 8 and N = 9, respectively) or PCOS patients (N = 10 for both phases).

PARTICIPANTS/MATERIALS, SETTING, METHODS

The activities of four target kinases were explored using kinase-responsive probes and selective inhibitors in lysates of in vitro decidualized ESCs and non-cultured ESCs isolated from tissue at different phases of the menstrual cycle. In the latter lysates, wide-scale proteomic and phosphoproteomic studies were further carried out. ROCK2 mRNA expression was explored in full tissue samples from controls or PCOS patients. The immunofluorescent staining of phosphorylated CFL1 was performed in full endometrial tissue samples, and in the in vitro decidualized fixed ESCs from controls or PCOS patients. Finally, the cellular migration properties were explored in live in vitro decidualized ESCs.

MAIN RESULTS AND THE ROLE OF CHANCE

During in vitro decidualization, the activities of PKA, protein kinase B (Akt/PKB), and ROCK are increased while the activity of casein kinase 2 (CK2) is decreased; these initial trends are observable after 4-day treatment (P < 0.05) and are further augmented following the 9-day treatment (P < 0.001) with mixtures containing progesterone and 8-Br-cAMP or forskolin. The presence of progesterone is necessary for activation of ROCK, yet it is dispensable in the case of PKA and Akt/PKB; in comparison to controls, PCOS patient-derived ESCs feature dampened response to progesterone. In non-cultured ESCs isolated from secretory vs proliferative phase tissue, only activity of ROCK is increased (P < 0.01). ROCK2 protein levels are slightly elevated in secretory versus proliferative ESCs (relative mean standard deviation < 50%), and ROCK2 mRNA is elevated in mid-secretory versus proliferative full tissue samples (P < 0.05) obtained from controls but not PCOS patients. Activation of ROCK2 downstream signalling results in increase of phospho-S3 CFL1 in secretory endometrium (P < 0.001) as well as in vitro decidualized ESCs (P < 0.01) from controls but not PCOS patients. ROCK2-triggered alterations in the cytoskeleton are reflected by the significantly decreased motility of in vitro decidualized ESCs (P < 0.05).

LARGE SCALE DATA

Proteomic and phosphoproteomic data are available via ProteomeXchange with identifier PXD026243.

LIMITATIONS, REASONS FOR CAUTION

The number of biological samples was limited. The duration of protocol for isolation of non-cultured ESCs from tissue can potentially affect phosphorylation pathways in cells, yet the possible artefacts were minimized by the identical treatment of proliferative and secretory samples.

WIDER IMPLICATIONS OF THE FINDINGS

The study demonstrated the benefits of combining the focussed kinase activity assay with wide-scale phosphoproteomics and showed the need for detailed elaboration of the in vitro decidualization protocols. ROCK was identified as the novel target of interest in decidualization, which requires closer attention in further studies-including the context of decidualization-related subfertility and infertility.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Estonian Ministry of Education and Research, and the Estonian Research Council (PRG1076, PRG454, PSG230 and PSG608), Enterprise Estonia (EU48695), Horizon 2020 innovation grant (ERIN, Grant no. EU952516) of the European Commission, the COMBIVET ERA Chair, H2020-WIDESPREAD-2018-04 (Grant agreement no. 857418), the Academy of Finland (Project grants 315921 and 321763), the Finnish Medical Foundation and The Sigrid Juselius Foundation. The authors confirm that they have no conflict of interest with respect to the content of this article.

Three-dimensional microengineered vascularised endometrium-on-a-chip

STUDY QUESTION

Can we reconstitute physiologically relevant 3-dimensional (3D) microengineered endometrium in-vitro model?

SUMMARY ANSWER

Our representative microengineered vascularised endometrium on-a-chip closely recapitulates the endometrial microenvironment that consists of three distinct layers including epithelial cells, stromal fibroblasts and endothelial cells in a 3D extracellular matrix in a spatiotemporal manner.

WHAT IS KNOWN ALREADY

Organ-on-a-chip, a multi-channel 3D microfluidic cell culture system, is widely used to investigate physiologically relevant responses of organ systems.

STUDY DESIGN, SIZE, DURATION

The device consists of five microchannels that are arrayed in parallel and partitioned by array of micropost. Two central channels are for 3D culture and morphogenesis of stromal fibroblast and endothelial cells. In addition, the outermost channel is for the culture of additional endometrial stromal fibroblasts that secrete biochemical cues to induce directional pro-angiogenic responses of endothelial cells. To seed endometrial epithelial cells, on Day 8, Ishikawa cells were introduced to one of the two medium channels to adhere on the gel surface. After that, the microengineered endometrium was cultured for an additional 5–6 days (total ∼ 14 days) for the purpose of each experiment.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Microfluidic 3D cultures were maintained in endothelial growth Medium 2 with or without oestradiol and progesterone. Some cultures additionally received exogenous pro-angiogenic factors. For the three distinct layers of microengineered endometrium-on-a-chip, the epithelium, stroma and blood vessel characteristics and drug response of each distinct layer in the microfluidic model were assessed morphologically and biochemically. The quantitative measurement of endometrial drug delivery was evaluated by the permeability coefficients.

MAIN RESULTS AND THE ROLE OF CHANCE

We established microengineered vascularised endometrium-on-chip, which consists of three distinct layers: epithelium, stroma and blood vessels. Our endometrium model faithfully recapitulates in-vivo endometrial vasculo-angiogenesis and hormonal responses displaying key features of the proliferative and secretory phases of the menstrual cycle. Furthermore, the effect of the emergency contraception drug levonorgestrel was evaluated in our model demonstrating increased endometrial permeability and blood vessel regression in a dose-dependent manner. We finally provided a proof of concept of the multi-layered endometrium model for embryo implantation, which aids a better understanding of the molecular and cellular mechanisms underlying this process.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

This report is largely an in-vitro study and it would be beneficial to validate our findings using human primary endometrial cells.

WIDER IMPLICATIONS OF THE FINDINGS

Our 3D microengineered vascularised endometrium-on-a-chip provides a new in-vitro approach to drug screening and drug discovery by mimicking the complicated behaviours of human endometrium. Thus, we suggest our model as a tool for addressing critical challenges and unsolved problems in female diseases, such as endometriosis, uterine cancer and female infertility, in a personalised manner.

STUDY FUNDING/COMPETING INTEREST(S)

This work is supported by funding from the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) to Y.J.K. (No. 2018R1C1B6003), to J.A. (No. 2020R1I1A1A01074136) and to H.S.K. (No. 2020R1C1C100787212). The authors report no conflicts of interest.

Deciphering the Role of PGRMC1 During Human Decidualization Using an In Vitro Approach

CONTEXT

Non-classical membrane progesterone receptor (mPRs) and progesterone receptor membrane component 1 (PGRMC1) expression have been detected in endometrium, but their role in decidualization had not yet been investigated. We previously demonstrated PGRMC1 downregulation in receptive endometrium and that its overexpression inhibits decidualization. Furthermore, during decidualization, PGRMC1 mainly interacts with proteins involved in biosynthesis, intracellular transport, and mitochondrial activity.

OBJECTIVE

To determine PGRMC1 and mPRs signaling role during decidualization.

METHODS

Isolated primary endometrial stromal cells (EnSC) were decidualized in vitro in the presence of classic stimuli (E2 + P4), PGRMC1 inhibitor (AG205), or membrane-impermeable P4 (P4-BSA). Endometrial biopsies were obtained from 19 fertile oocyte donors attending the IVI-Valencia in vitro fertilization (IVF) clinic. EnSC decidualization was evaluated by prolactin ELISA and F-actin immunostaining. Progesterone receptor localization was evaluated by immunofluorescence. EnSC transcriptomic profiles were analyzed by microarray technology.

RESULTS

PGRMC1 inhibition during EnSC decidualization (AG205dEnSC) does not interfere with EnSC cytoskeletal rearrangements and prolactin secretion. However, global transcriptional profiling revealed more differentially expressed genes in AG205dEnSC than in dEnSC, compared with nondecidualized EnSC (ndEnSC). In silico analysis showed that PGRMC1 inhibition upregulated more genes related to metabolism, molecular transport, and hormonal biosynthesis compared with control dEnSC. EnSC decidualized in the presence of P4-BSA showed a similar behavior as ndEnSC in terms of morphological features, absence of prolactin secretion, and transcriptomic pattern.

CONCLUSION

Our findings associate PGRMC1 to hormonal biosynthesis, metabolism, and vesicular transport-important cellular functions for dEnSC supporting pregnancy. Activation of membrane P4 receptor signaling alone was unable to induce downstream effects needed for proper decidualization.

Endometrial stromal cell proteomic analysis reveals LIM and SH3 protein 1 (LASP1) plays important roles in the progression of adenomyosis

Adenomyosis is one of the most common gynecological disorders that the molecular events underlying its pathogenesis remain not fully understood. Prior studies have shown that endometrial stromal cells (ESCs) played crucial roles in the pathogenesis of adenomyosis. In this study, we utilized two-dimensional gel electrophoresis combined with protein identification by mass spectrometry (2D/MS) proteomics analysis to compare the differential protein expression profile between the paired eutopic and ectopic ESCs (EuESCs and EcESCs) in adenomyosis, and a total of 32 significantly altered protein spots were identified. Among which, the expression of LIM and SH3 protein 1 (LASP1) was increased significantly in EcESCs compared to EuESCs. Immunohistochemical assay showed that LASP1 was overexpressed in the stromal cells of ectopic endometriums compared to eutopic endometriums; further functional analyses revealed that LASP1 overexpression could enhance cell proliferation, migration and invasion of EcESCs. Furthermore, we also showed that the dysregulated expression of LASP1 in EcESCs was associated with DNA hypermethylation in the promoter region of the LASP1 gene. However, the detailed molecular mechanisms of enhancing cell proliferation, invasion and migration caused by upregulated LASP1 in adenomyosis needs further study. For the first time, our data suggested that LASP1 plays important roles in the pathogenesis of adenomyosis, and could serve as a prognostic biomarker of adenomyosis.

Immune Tolerance of the Human Decidua

The endometrium is necessary for implantation, complete development of the placenta, and a successful pregnancy. The endometrium undergoes repeated cycles of proliferation, decidualization (differentiation), and shedding during each menstrual cycle. The endometrium—including stromal, epithelial, vascular endothelial, and immune cells—is both functionally and morphologically altered in response to progesterone, causing changes in the number and types of immune cells. Immune cells make up half of the total number of endometrial cells during implantation and menstruation. Surprisingly, immune tolerant cells in the endometrium (uterine natural killer cells, T cells, and macrophages) have two conflicting functions: to protect the body by eliminating pathogenic microorganisms and other pathogens and to foster immunological change to tolerate the embryo during pregnancy. One of the key molecules involved in this control is the cytokine interleukin-15 (IL-15), which is secreted by endometrial stromal cells. Recently, it has been reported that IL-15 is directly regulated by the transcription factor heart- and neural crest derivatives-expressed protein 2 in endometrial stromal cells. In this review, we outline the significance of the endometrium and immune cell population during menstruation and early pregnancy and describe the factors involved in immune tolerance and their involvement in the establishment and maintenance of pregnancy.

Flow-enhanced priming of hESCs through H2B acetylation and chromatin decondensation

BACKGROUND

Distinct mechanical stimuli are known to manipulate the behaviors of embryonic stem cells (ESCs). Fundamental rationale of how ESCs respond to mechanical forces and the potential biological effects remain elusive. Here we conducted the mechanobiological study for hESCs upon mechanomics analysis to unravel typical mechanosensitive processes on hESC-specific fluid shear.

METHODS

hESC line H1 was subjected to systematically varied shear flow, and mechanosensitive proteins were obtained by mass spectrometry (MS) analysis. Then, function enrichment analysis was performed to identify the enriched gene sets. Under a steady shear flow of 1.1 Pa for 24 h, protein expressions were further detected using western blotting (WB), quantitative real-time PCR (qPCR), and immunofluorescence (IF) staining. Meanwhile, the cells were treated with 200 nM trichostatin (TSA) for 1 h as positive control to test chromatin decondensation. Actin, DNA, and RNA were then visualized with TRITC-labeled phalloidin, Hoechst 33342, and SYTO® RNASelect™ green fluorescent cell stain (Life Technologies), respectively. In addition, cell stiffness was determined with atomic force microscopy (AFM) and annexin V-PE was used to determine the apoptosis with a flow cytometer (FCM).

RESULTS

Typical mechanosensitive proteins were unraveled upon mechanomics analysis under fluid shear related to hESCs in vivo. Functional analyses revealed significant alterations in histone acetylation, nuclear size, and cytoskeleton for hESC under shear flow. Shear flow was able to induce H2B acetylation and nuclear spreading by CFL2/F-actin cytoskeletal reorganization. The resulting chromatin decondensation and a larger nucleus readily accommodate signaling molecules and transcription factors.

CONCLUSIONS

Shear flow regulated chromatin dynamics in hESCs via cytoskeleton and nucleus alterations and consolidated their primed state.

Alterations in the distribution of actin and its binding proteins in the porcine endometrium during early pregnancy: Possible role in epithelial remodeling and embryo adhesion

During early pregnancy, uterine epithelial cells undergo major transformations in their cytoskeleton that make the endometrium receptive for conceptus attachment. Actin binding proteins (ABPs) such as cofilin, gelsolin, and vinculin are involved in regulating actin polymerization, severing or crosslinking actin to integrins. However, whether ABPs are involved in epithelial remodeling or embryo adhesion in pigs is unknown. Therefore, the expression and distribution of these proteins were investigated in porcine endometrium on Days 10 and 13 (pre-implantation period), and 16 (attachment phase) of the estrous cycle or pregnancy. While day and pregnancy status had no effect on ABP gene expression, the protein abundance of vinculin was significantly higher on Day 13 than on Day 10 (p < 0.05) of the estrous cycle, and its abundance was highest on Day 16 in the pregnant endometrium. Immunofluorescent staining showed alterations in the distribution of these proteins depending on the day of the estrous cycle or early pregnancy examined. Double immunofluorescent staining for the ABPs and actin revealed that while cofilin co-localized with actin in the apical epithelium on Days 13 and 16 of the estrous cycle, in pregnant animals, it was strongly associated with actin in the sub-epithelial stroma of the endometrium. Gelsolin was also co-localized with actin in the apical epithelium on Days 13 and 16 of the estrous cycle, but this association was absent in the pregnant endometrium. Vinculin co-localized with actin in the sub-epithelial stroma on Days 13 and 16 irrespective of the reproductive status, but was additionally associated with actin in the apical epithelium on Day 16 of pregnancy. Vinculin interacted with phosphorylated focal adhesion kinase in the endometrial epithelium, and the interaction was dependent on estradiol-17β, a conceptus-secreted pregnancy-recognition factor in pigs. Furthermore, silencing vinculin in the endometrial epithelial cells negatively affected trophoblast adhesion to them. In conclusion, the influence of stage and reproductive status on the specific localization of actin and its binding proteins in the porcine endometrium suggests that they play a role in regulating the endometrial cytoskeleton. Moreover, vinculin may facilitate conceptus attachment to the epithelium by interacting with focal adhesion kinase.

Defective decidualization during and after severe preeclampsia reveals a possible maternal contribution to the etiology

In preeclampsia (PE), cytotrophoblast (CTB) invasion of the uterus and spiral arteries is often shallow. Thus, the placenta's role has been a focus. In this study, we tested the hypothesis that decidual defects are an important determinant of the placental phenotype. We isolated human endometrial stromal cells from nonpregnant donors with a previous pregnancy that was complicated by severe PE (sPE). Compared with control cells, they failed to decidualize in vitro as demonstrated by morphological criteria and the analysis of stage-specific antigens (i.e., IGFBP1, PRL). These results were bolstered by global transcriptional profiling data that showed they were transcriptionally inert. Additionally, we used laser microdissection to isolate the decidua from tissue sections of the maternal-fetal interface in sPE. Global transcriptional profiling revealed defects in gene expression. Also, decidual cells from patients with sPE, which dedifferentiated in vitro, failed to redecidualize in culture. Conditioned medium from these cells failed to support CTB invasion. To mimic aspects of the uterine environment in normal pregnancy, we added PRL and IGFBP1, which enhanced invasion. These data suggested that failed decidualization is an important contributor to down-regulated CTB invasion in sPE. Future studies will be aimed at determining whether this discovery has translational potential with regard to assessing a woman's risk of developing this pregnancy complication.

miR-181b-5p Modulates Cell Migratory Proteins, Tissue Inhibitor of Metalloproteinase 3, and Annexin A2 During In Vitro Decidualization in a Human Endometrial Stromal Cell Line

Decidualization is essential for successful embryo implantation and is regulated by concerted actions of growth factors and hormones. More recently, microRNAs, small RNA molecules that regulate posttranscriptional gene expression, have been implicated to play a role in the decidualization process. Of these microRNAs, miR-181b-5p has been associated with decidualization but its precise role and targets are not well established. To address this gap in our knowledge, we assessed the expression of miR-181b-5p, and its target tissue inhibitor of metalloproteinase 3 (TIMP-3), during in vitro decidualization using the well-characterized human endometrial stromal cell line, t-HESC. miR-181b-5p expression was highest prior to decidualization and significantly decreased in response to decidualization stimulus. In contrast, TIMP-3 expression was absent prior to in vitro decidualization and increased during decidualization. Regulation of TIMP-3 expression by miR-181b-5p was confirmed in vitro by quantitative reverse transcription polymerase chain reaction (qRT-PCR), Western blot analysis, and 3' untranslated region reporter constructs. To identify unforeseen targets of miR-181b-5p during in vitro decidualization, t-HESC cells were transfected with pre- miR-181b-5p, and protein profiles were determined by 2-dimensional differential in-gel electrophoresis followed by matrix-assisted laser desorption-ionization time-of-flight/time-of-flight (MALDI TOF/TOF) tandem mass spectrometry. Of these proteins, several downregulated proteins associated with cell migration were identified including annexin A2, which we subsequently confirmed by qRT-PCR and Western blot analysis to be regulated by miR-181b-5p. In conclusion, miR-181b-5p is downregulated during the process of in vitro decidualization and may regulate the expression of proteins associated with cell migration including TIMP-3 and annexin A2.

Proteomic and network analysis of pregnancy-induced changes in the porcine endometrium on Day 12 of gestation

Conceptus attachment is a time-sensitive process that requires a synchronized uterine environment created by molecular changes in the endometrium in response to ovarian hormones and conceptus signals. Porcine conceptuses undergo rapid elongation and differentiation, and secrete estrogens that serve as maternal-recognition-of-pregnancy signals during the peri-implantation period (Days 11-12). Pregnancy-induced proteomic changes in the porcine endometrium were measured during this period using two-dimensional differential gel electrophoresis of endometrial protein lysates from Day-12 pregnant versus non-pregnant animals (n = 4 each). Forty-four differentially abundant proteins in the pregnant endometrium were identified by mass spectrometry. The pregnant endometrium was associated with a unique protein profile, revealed by principal component analysis. A pregnancy-dependent increase in the abundance of serpins, cofilin, annexin A2, aldose reductase, cyclophilin, protein disulphide isomerase A3, and peroxiredoxin 1 was observed. Western blotting for some of the selected proteins confirmed their enrichment during pregnancy. Ingenuity pathway analysis identified several functions specifically over-represented among the differentially abundant proteins in the pregnant endometrium, including calcium signaling, angiogenesis, leukocyte migration, and cell movement. Interleukin-1 beta and beta-estradiol were identified as upstream regulators of several high-abundance proteins from pregnancy. Therefore, signals from porcine conceptuses, such as estrogens, interleukin 1B, and epidermal growth factor, either alone or in coordination with other factors, prepare the uterus for implantation. Mol. Reprod. Dev. 83: 827-841, 2016 © 2016 Wiley Periodicals, Inc.

Proteomic analysis of porcine endometrial tissue during peri-implantation period reveals altered protein abundance

In mammals, successful pregnancy depends upon the readiness of uterus for implantation, followed by correct communication between the endometrium and the developing conceptus. The objective of this study was to elucidate changes in protein abundance associated with progression of estrous cycle and pregnancy from Day 9 to Day 12. We analyzed porcine endometrial tissue lysates by 2D-DIGE. Abundance of several proteins was altered depending upon the pregnancy status of animals. MALDI-TOF/TOF was used to identify a number of these proteins. Endometrial proteins that increased from Day 9 to Day 12 of cycle included annexin A4, beta-actin, apolipoprotein, ceruloplasmin and afamin. Changes in protein abundances associated with conceptus secreted factors, including haptoglobin, prolyl-4-hydroxylase, aldose-reductase and transthyretin, were also observed. Functional analysis revealed that endometrial proteins with altered abundance on Day 12 irrespective of the reproductive status were related to growth and remodeling, acute phase response and free radical scavenging, whereas transport and small molecule biochemistry were the functions activated in the pregnant endometrium as compared to the cyclic endometrium. These data provide information on dynamic physiological processes associated with uterine endometrial function of the cyclic and pregnant endometrium during period of maternal recognition of pregnancy in pigs and may potentially demonstrate a protein profile associated with successful pregnancy.

BIOLOGICAL SIGNIFICANCE

In pigs, the fertility rates are generally very high but the early embryonic loss that occurs during the second and third weeks of gestation critically affects the potential litter size. Temporal changes that take place in the uterine environment during the period of early pregnancy in pigs and a cross-talk between the uterus and the embryo play an important role in embryonic survival and successful pregnancy. A better understanding of the molecular changes associated with these processes will pave way for understanding of endometrial functions and help towards increasing embryo survival. In this study, we present a 2D-DIGE based analysis of changes in porcine endometrial proteome that are associated with progression of cycle and progression of pregnancy. The network analysis of the results clearly revealed the pathways that are involved in rendering the endometrium receptive to the presence of embryo and also the changes that are result of molecular communication between the endometrium and the conceptuses. This comprehensive identification of proteomic changes in the porcine endometrium could be a foundation for targeted studies of proteins and pathways potentially involved in abnormal endometrial receptivity, placentation and embryo loss.

Endometrial stromal cells and decidualized stromal cells: origins, transformation and functions

Decidualization of endometrium, which is characterized by endometrial stromal cell (ESC) decidualization, vascular reconstruction, immune cell recruitment, and plentiful molecule production, is a crucial step for uterus to become receptive for embryo. When implantation takes place, ESCs surround and directly interact with embryo. Decidualized stromal cells (DSCs) are of great importance in endometrial decidualization, having a broad function in regulating immune activity and vascular remodeling of uterus. DSCs are shown to have a higher metabolic level and looser cytoskeleton than ESCs. What's the origin of ESCs and how ESCs successfully transform into DSCs had puzzled scientists in the last decades. Breakthrough had been achieved recently, and many studies had elucidated some of the characters and functions of DSCs. However, several questions still remain unclear. This paper reviews current understanding of where ESCs come from and how ESCs differentiate into DSCs, summarizes some characters and functions of DSCs, analyzes current studies and their limitations and points out research areas that need further investigation.

High cofilin-1 levels correlate with cisplatin resistance in lung adenocarcinomas

High cofilin-1 levels have been shown to be an accurate prognostic biomarker in non-small cell lung cancer (NSCLC) and a predictive factor in drug resistance. Herein we explore the role of cofilin-1 in cis-diamminedichloroplatinum(II) (cisplatin) resistance. We evaluated cofilin-1 levels in intrinsically cisplatin-resistant A549 (ICR-A549) cells and determined the cisplatin toxicity in A549 cells transiently transfected and overexpressing CFL1 plasmid. Moreover, expression levels (activity) of the CFL1 gene network were analyzed in a cisplatin-resistant human lung adenocarcinoma cell panel. ICR-A549 cells, selected by challenging parental cells with 10-fold drug GI50 value, presented a sixfold increase in cisplatin GI50 value and an increased cofilin-1 immunocontent (P < 0.01). In addition, cells transfected with cofilin-1 became more resistant to cisplatin (P < 0.01). High activity of the CFL1 gene network was found in a cisplatin-resistant adenocarcinoma cell panel (P < 0.01). In vitro evidences suggest that cofilin-1 is a biological predictor of cisplatin resistance, supporting new treatment initiatives based on cofilin-1 levels to guide chemotherapeutic interventions in NSCLC patients.

Characterization and predicted role of the microRNA expression profile in amnion from obese pregnant women

Maternal obesity and nutrient excess in utero increase the risk of future metabolic diseases. The mechanisms underlying this process are poorly understood, but probably include genetic, epigenetic alterations and changes in fetal nutrient supply. We have studied the microRNA (miRNA) expression profile in amnion from obese and control women at delivery to investigate if a specific miRNA signature is associated with obesity. The expression profile of 365 human miRNAs was evaluated with the TaqMan Array in amnion from 10 obese and 5 control (prepregnancy body mass index (BMI) >30 and <25 kg m(-2), respectively) women at delivery. Target genes and miRNA-regulated pathways were predicted by bioinformatics. Anthropometric and biochemical parameters were also measured in mothers and newborns. Seven miRNAs were expressed only in obese women (miR-422b, miR-219, miR-575, miR-523, miR-579, miR-618 and miR-659), whereas 13 miRNAs were expressed at a higher level and 12 miRNAs at a lower level in obese women than in controls. MicroRNAs significantly downregulated the neurotrophin, cancer/ErbB, mammalian target of rapamycin, insulin, adipocytokine, actin cytoskeleton and mitogen-activated protein kinase signaling pathways. In conclusion, we show that the miRNA profile is altered in amnion during obesity and hypothesize that this could affect pathways important for placental growth and function, thereby contributing to an increase in the newborn's risk of future metabolic diseases.

miRNA signature and Dicer requirement during human endometrial stromal decidualization in vitro

Decidualization is a morphological and biochemical transformation of endometrial stromal fibroblast into differentiated decidual cells, which is critical for embryo implantation and pregnancy establishment. The complex regulatory networks have been elucidated at both the transcriptome and the proteome levels, however very little is known about the post-transcriptional regulation of this process. miRNAs regulate multiple physiological pathways and their de-regulation is associated with human disorders including gynaecological conditions such as endometriosis and preeclampsia. In this study we profile the miRNAs expression throughout human endometrial stromal (hESCs) decidualization and analyze the requirement of the miRNA biogenesis enzyme Dicer during this process. A total of 26 miRNAs were upregulated and 17 miRNAs downregulated in decidualized hESCs compared to non-decidualized hESCs. Three miRNAs families, miR-181, miR-183 and miR-200, are down-regulated during the decidualization process. Using miRNAs target prediction algorithms we have identified the potential targets and pathways regulated by these miRNAs. The knockdown of Dicer has a minor effect on hESCs during in vitro decidualization. We have analyzed a battery of decidualization markers such as cell morphology, Prolactin, IGFBP-1, MPIF-1 and TIMP-3 secretion as well as HOXA10, COX2, SP1, C/EBPß and FOXO1 expression in decidualized hESCs with decreased Dicer function. We found decreased levels of HOXA10 and altered intracellular organization of actin filaments in Dicer knockdown decidualized hESCs compared to control. Our results provide the miRNA signature of hESC during the decidualization process in vitro. We also provide the first functional characterization of Dicer during human endometrial decidualization although surprisingly we found that Dicer plays a minor role regulating this process suggesting that alternative biogenesis miRNAs pathways must be involved in human endometrial decidualization.

Annexin A2 is critical for embryo adhesiveness to the human endometrium by RhoA activation through F-actin regulation

Annexin A2 (ANXA2) is present in vivo in the mid- and late-secretory endometria and is mainly localized in the luminal epithelium. Our aim was to evaluate its function in regulating the human implantation process. With an in vitro adhesion model, constructed to evaluate how the mouse embryo and JEG-3 spheroids attach to human endometrial epithelial cells, we demonstrated that ANXA2 inhibition significantly diminishes embryo adhesiveness. ANXA2 is also implicated in endometrial epithelial cell migration and trophoblast outgrowth. ANXA2 was seen to be linked to the RhoA/ROCK pathway and to regulate cell adhesion. We noted that ANXA2 inhibition significantly reduces active RhoA, although RhoA inactivation does not alter the ANXA2 levels. RhoA inactivation and ROCK inhibition also moderate embryo adhesiveness to endometrial epithelial cells. We corroborated that the induction of constitutively active RhoA partially reverses the effects of ANXA2 inhibition on endometrial adhesiveness. These molecules colocalize on the plasma membrane of endometrial epithelial cells, and a large proportion of ANXA2 and RhoA are colocalized in the F-actin networks. The functional effects of ANXA2 inhibition and RhoA/ROCK inactivation are associated with significant alterations in F-actin organization and its depolymerization. ANXA2 may act upstream of the RhoA/ROCK pathway by regulating F-actin remodeling and is a key factor in human endometrial adhesiveness.

Interaction of the conceptus and endometrium to establish pregnancy in mammals: role of interleukin 1β

Implantation and the establishment of pregnancy in mammals involves an intricate interplay of hormones, cytokines, growth factors, proteins, lipids, ions and the extracellular matrix between the uterine epithelium, stroma, immune cells and the conceptus trophectoderm. The divergent nature of implantation in the mouse, human and pig provides not only an interesting contrast in the establishment of pregnancy and early embryonic development but also intriguing similarities with regard to early endometrial-conceptus signaling. An interesting pro-inflammatory cytokine expressed in a number of mammalian species during the period of implantation is interleukin-1β (IL1B). The presence of IL1B might be involved with immunotolerance at the maternal-placental interface and has been proposed as one of the mediators in placental viviparity. The production of IL1B and other proinflammatory cytokines might play a role in establishing pregnancy through modulation of the nuclear factor kappa-B (NFKB) system in a number of species. A model for the regulation of cellular progesterone receptor expression and NFKB activation for endometrial receptivity and conceptus attachment is continuing to evolve and is discussed in the present review.

Kruppel-like factor 5 (KLF5) is critical for conferring uterine receptivity to implantation

A blastocyst will implant only when the uterus becomes receptive. Following attachment, luminal epithelial cells undergo degeneration at the site of the blastocyst. Although many genes critical for uterine receptivity are primarily regulated by ovarian hormones, Kruppel-like factor 5 (KLF5), a zinc finger-containing transcription factor, is persistently expressed in epithelial cells independently of ovarian hormones. Loss of uterine Klf5 causes female infertility due to defective implantation. Cox2 is normally expressed in the luminal epithelium and stroma at the site of blastocyst attachment, but luminal epithelial COX2 expression is absent with loss of Klf5. This is associated with the retention of the epithelium around the implantation chamber with arrested embryonic growth. These results suggest that Klf5 is indispensable for normal implantation.

Proteomic analysis of pregnancy-related proteins from pig uterus endometrium during pregnancy

Many important molecular events associated with implantation and development occur within the female reproductive tract, especially within the uterus endometrium, during pregnancy periods. The endometrium includes the mucosal lining of the uterus, which provides a suitable site for implantation and development of a fertilized egg and fetus. To date, the molecular cascades in the uterus endometrium during pregnancy periods in pigs have not been elucidated fully. In this study, we compared the functional regulated proteins in the endometrium during pregnancy periods with those in non-pregnant conditions and investigated changes in expression patterns during pregnancy (days 40, 70, and 93) using two-dimensional gel electrophoresis (2-DE) and western blotting. The functional regulated proteins were identified and discovered from differentially expressed proteins in the uterus endometrium during pregnancy. We discovered 820 protein spots in a proteomic analysis of uterus endometrium tissues with 2-DE gels. We identified 63 of the 98 proteins regulated differentially among non-pregnant and pregnant tissues (matched and unmatched spots). Interestingly, 10 of these 63 proteins are development-, cytoskeleton- and chaperon-related proteins such as transferrin, protein DJ-1, transgelin, galectin-1, septin 2, stathmin 1, cofilin 1, fascin 1, heat shock protein (HSP) 90β and HSP 27. The specific expression patterns of these proteins in the endometrium during pregnancy were confirmed by western blotting. Our results suggest that the expressions of these genes involved in endometrium function and endometrium development from early to late gestation are associated with the regulation of endometrium development for maintaining pregnancy.

Cofilin and slingshot localization in the epithelium of uterine endometrium changes during the menstrual cycle and in endometriosis

Regulation of the actin cytoskeleton is essential for epithelial cell polarity and protein trafficking within human uterine epithelium. The actin-binding protein cofilin is involved in regulation of actin dynamics by promoting actin branching and cytoskeleton reorganization. Dual immunohistochemical staining of cofilin and G-actin (represented by DNAse I staining) revealed cofilin-G-actin colocalization in the apical side of luminal epithelial cells of human uterine endometrium during the proliferative phase of the menstrual cycle. Interestingly, during the secretory phase of the menstrual cycle, cofilin was only present on the basolateral side. To determine whether the disease endometriosis causes a different pattern of actin remodeling, we investigated an established baboon model of induced endometriosis. The cofilin pattern in the secretory phase of baboons with endometriosis was similar to the proliferative phase in normal animals; cofilin was observed in the apical parts of luminal and glandular epithelium. A phosphatase regulating the activity of cofilin, slingshot (SSH1), revealed a similar staining pattern within these tissues. These patterns were confirmed through quantitative image analysis. Quantification of messenger RNA (mRNA) detected upregulated SSH1 and suggested a progesterone resistance-related pattern of nuclear steroid hormone receptors, but no change in membrane progesterone receptors (mPR alpha or mPR beta) was observed in endometriosis. Our data indicate that the severe dyssynchrony during menstrual cycle phases in endometriosis is connected with improper cytoskeleton rearrangements. We suggest that cofilin-mediated actin reorganization in uterine epithelial cells might be important in preparation for blastocyst implantation; dysregulation of this reorganization may lead to decreased fertility in endometriosis.

Modeling human endometrial decidualization from the interaction between proteome and secretome

CONTEXT

Decidualization of the human endometrium, which involves morphological and biochemical modifications of the endometrial stromal cells (ESCs), is a prerequisite for adequate trophoblast invasion and placenta formation.

OBJECTIVE

This study aims to investigate the proteome and secretome of in vitro decidualized ESCs. These data were combined with published genomic information and integrated to model the human decidualization interactome.

DESIGN

Prospective experimental case-control study.

SETTING

A private research foundation.

PATIENTS

Sixteen healthy volunteer ovum donors.

INTERVENTION

Endometrial samples were obtained, and ESCs were isolated and decidualized in vitro.

MAIN OUTCOME MEASURES

Two-dimensional difference in-gel electrophoresis, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry, Western blot, human protein cytokine array, ELISA, and bioinformatics analysis were performed.

RESULTS

The proteomic analysis revealed 60 differentially expressed proteins (36 over- and 24 underexpressed) in decidualized versus control ESCs, including known decidualization markers (cathepsin B) and new biomarkers (transglutaminase 2, peroxiredoxin 4, and the ACTB protein). In the secretomic analysis, a total of 13 secreted proteins (11 up- and 2 down-regulated) were identified, including well-recognized markers (IGF binding protein-1 and prolactin) and novel ones (myeloid progenitor inhibitory factor-1 and platelet endothelial cell adhesion molecule-1). These proteome/secretome profiles have been integrated into a decidualization interactome model.

CONCLUSIONS

Proteomic and secretomic have been used as hypothesis-free approaches together with complex bioinformatics to model the human decidual interactome for the first time. We confirm previous knowledge, describe new molecules, and we have built up a model for human in vitro decidualization as invaluable tool for the diagnosis, therapy, and interpretation of biological phenomena.

Proteomic approach identifies alterations in cytoskeletal remodelling proteins during decidualization of human endometrial stromal cells

Decidualization is a tissue remodelling process within the uterus in preparation for embryo implantation and pregnancy. In this study we isolated primary human endometrial stromal cells and stimulated decidualization with cAMP. We then used 2D- differential in-gel electrophoresis (DIGE) to identify proteins induced by decidualization. Eighty-eight out of 2714 spots were differentially regulated, 18 of which were assigned clear identities by mass spectrometry. Many of these are proteins known to be associated with cell structure and cytoskeletal remodelling. We validated five of these proteins by Western blot and immunohistochemistry on human endometrial tissue. The validated proteins are caldesmon 1, src substrate contactin 8, tropomyosin alpha-4 chain, protein disulfide isomerase 1A, and LIM and SH3 domain protein. With the exception of caldesmon 1, none of the identified proteins have previously been associated with decidualization. This study provides insight into our understanding of decidualization, which is important for successful embryo implantation and establishment of pregnancy.

Silencing of cofilin-1 gene attenuates biological behaviours of stromal cells derived from eutopic endometria of women with endometriosis

BACKGROUND

Eutopic endometria with endometriosis (EMs) differ dramatically from normal endometria, physiologically and biochemically, yet the pathogenesis of EMs remains unclear. Cofilin-1 (CFL1), a critical modulator of the actin cystoskeleton, is associated with tumour progression, cell motility, cell adhesion, cell invasion and angiogenesis. Although eutopic endometria with EMs exhibit many malignant-like behaviours and a higher expression of CFL1 than normal endometria, the effects of CFL1 on the pathogenesis of EMs are unknown. The aim of this study was to explore the role of CFL1 expression in proliferation, apoptosis, adhesion, invasion, angiogenesis and ultrastructure of endometrial cells.

METHODS

We isolated and cultured stromal cells derived from the eutopic endometria of 30 patients with advanced ovarian EMs (ESCs, Stromal Cells of eutopic endometria in Endometriosis patients) and 30 control patients without EMs (NSCs, Stromal Cells of eutopic endometria in Non-endometriosis patients), and evaluated their proliferation, apoptosis, adhesion, invasion and expression of markers of adhesion, invasion and angiogenesis in vitro. In addition, these functions were examined after short hairpin RNA (shRNA) was used to silence the CFL1 gene in ESCs, and pEGFP-N1-CFL recombinant plasmid was transiently transfected into NSCs to up-regulate CFL1 expression.

RESULTS

Under basal conditions, CFL1 mRNA and protein were overexpressed in ESCs. Proliferation, adhesion, invasion and markers of adhesion, invasion and angiogenesis were enhanced in ESCs compared with NSCs; in contrast, the apoptosis rate was lower in ESCs than in NSCs. Silencing the CFL1 gene in ESCs markedly attenuated proliferation, adhesion, invasion and expression of the markers, but enhanced apoptosis. Conversely, up-regulation of CFL1 in NSCs increased proliferation, adhesion, invasion and expression of the markers but reduced apoptosis.

CONCLUSIONS

The overexpression of CFL1 in ESCs is associated with enhanced proliferation, adhesion, invasion and angiogenesis and reduced apoptosis in EMs. These malignant-like behaviours of ESCs in EMs can be attenuated by inducing CFL1 gene silencing with shRNA interference.

Human transcriptional coactivator with PDZ-binding motif (TAZ) is downregulated during decidualization

Transcriptional coactivator with PDZ-binding motif (TAZ) is known to bind to a variety of transcription factors to control cell differentiation and organ development. However, its role in uterine physiology has not yet been described. To study its regulation during the unique process of differentiation of fibroblasts into decidual cells (decidualization), we utilized the human uterine fibroblast (HuF) in vitro cell model. Immunocytochemistry data demonstrated that the majority of the TAZ protein is localized in the nucleus. Treatment of HuF cells with the embryonic stimulus cytokine interleukin 1 beta in the presence of steroid hormones (estradiol-17 beta and medroxyprogesterone acetate) for 13 days did not cause any apparent TAZ mRNA changes but resulted in a significant TAZ protein decline (approximately 62%) in total cell lysates. Analysis of cytosolic and nuclear extracts revealed that the decline of total TAZ was caused primarily by a drop of TAZ protein levels in the nucleus. TAZ was localized on the peroxisome proliferator-activated receptor response element site (located at position -1200 bp relative to the transcription start site) of the genomic region of decidualization marker insulin-like growth factor-binding protein 1 (IGFBP1) in HuF cells as detected by chromatin immunoprecipitation. TAZ is also present in human endometrium tissue as confirmed by immunohistochemistry. During the secretory phase of the menstrual cycle, specific TAZ staining particularly diminishes in the stroma, suggesting its participation during the decidualization process, as well as implantation. During early baboon pregnancy, TAZ protein expression remains minimal in the endometrium close to the implantation site. In summary, the presented evidence shows for the first time to date TAZ protein in the human uterine tract, its downregulation during in vitro decidualization, and its localization on the IGFBP1 promoter region, all of which indicate its presence in the uterine differentiation program during pregnancy.