Heparan sulfate proteoglycans and their binding proteins in embryo implantation and placentation

The prognostic value and immunological role of SULF2 in adrenocortical carcinoma

Background

Adrenocortical carcinoma (ACC) represents the rare urological epithelial cancer of urinary tract, which has a large mass and is usually diagnosed at the advanced stage, thus inducing the poor prognosis. As a result, early detection and diagnosis are more important for the prognosis rather than the treatment of ACC. There is evidence supporting the association of Sulfatase2 (SULF2) with bladder cancer. However, the relationships of SULF2 with the clinical features and immune infiltration of ACC remain unclear.

Methods

This work comprehensively investigated the different expression levels of SULF2 within ACC and its prognostic significance through various databases including Gene Expression Profiling Interaction Analysis (GEPIA), Tumor Immune Estimation Resource (TIMER), The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), Kaplan-Meier (KM) plotter and UALCAN. Besides, SULF2 levels within different tumor and paraneoplastic tissues were examined based on Human Protein Atlas (HPA) and TIMER. Afterwards, this study identified differentially expressed genes (DEGs) in high-compared with low-SULF2-expression groups. To predict the possible interaction between SULF2 and its targets, a protein-protein interaction (PPI) network was constructed based on relevant data collected in STRING database. Besides, the SULF2 functional annotation was carried out, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and GSEA. In addition, gene mutation analysis was also performed based on the cBioPortal database. The relation of SULF2 with immune infiltration was analyzed from various aspects by using the resources of various databases including TIMER, TISIDB, and GEPIA, which was first reported in this work. Finally, R package was utilized to plot the receiver operating characteristic (ROC) curves of diagnosis, time-dependent survival, and the association of SULF2 with cancer stage and the nomogram model. Finally, CellMiner dataset was adopted for SULF2 correlation as well as drug sensitivity analysis.

Results

Relative to healthy people, SULF2 level markedly elevated within ACC tissues. Besides, SULF2 up-regulation significantly predicted the dismal prognostic outcome, which may be an important prognostic factor. Afterwards, the PPI network was constructed, and the possible link of SULF2 with the corresponding targets was predicted. Besides, up-regulated SULF2 expression was tightly related to immune regulation and tumor-infiltration immune cell (TIICs), including CD8⁺, CD4⁺ and mast cells. Finally, SULF2 expression was speculated to help determine the sensitivity of certain drugs.

Conclusions

SULF2 may offer a new therapeutic target for ACC patients and become an important potential prognostic biomarker.

Trophoblast derived extracellular vesicles specifically alter the transcriptome of endometrial cells and may constitute a critical component of embryo-maternal communication

BACKGROUND

The period of time when the embryo and the endometrium undergo significant morphological alterations to facilitate a successful implantation-known as "window of implantation"-is a critical moment in human reproduction. Embryo and the endometrium communicate extensively during this period, and lipid bilayer bound nanoscale extracellular vesicles (EVs) are purported to be integral to this communication.

METHODS

To investigate the nature of the EV-mediated embryo-maternal communication, we have supplemented trophoblast analogue spheroid (JAr) derived EVs to an endometrial analogue (RL 95-2) cell layer and characterized the transcriptomic alterations using RNA sequencing. EVs derived from non-trophoblast cells (HEK293) were used as a negative control. The cargo of the EVs were also investigated through mRNA and miRNA sequencing.

RESULTS

Trophoblast spheroid derived EVs induced drastic transcriptomic alterations in the endometrial cells while the non-trophoblast cell derived EVs failed to induce such changes demonstrating functional specificity in terms of EV origin. Through gene set enrichment analysis (GSEA), we found that the response in endometrial cells was focused on extracellular matrix remodelling and G protein-coupled receptors' signalling, both of which are of known functional relevance to endometrial receptivity. Approximately 9% of genes downregulated in endometrial cells were high-confidence predicted targets of miRNAs detected exclusively in trophoblast analogue-derived EVs, suggesting that only a small proportion of reduced expression in endometrial cells can be attributed directly to gene silencing by miRNAs carried as cargo in the EVs.

CONCLUSION

Our study reveals that trophoblast derived EVs have the ability to modify the endometrial gene expression, potentially with functional importance for embryo-maternal communication during implantation, although the exact underlying signalling mechanisms remain to be elucidated.

Sulfatase 2-Induced Cancer-Associated Fibroblasts Promote Hepatocellular Carcinoma Progression via Inhibition of Apoptosis and Induction of Epithelial-to-Mesenchymal Transition

Background

Sulfatase 2 (SULF2) removes the 6-O-sulfate groups from heparan sulfate proteoglycans (HSPG) and consequently alters the binding sites for various signaling molecules. Here, we elucidated the role of SULF2 in the differentiation of hepatic stellate cells (HSCs) into carcinoma-associated fibroblasts (CAFs) in the hepatocellular carcinoma (HCC) microenvironment and the mechanism underlying CAF-mediated HCC growth.

Methods

The clinical relevance of SULF2 and CAFs was examined using in silico and immunohistochemical (IHC) analyses. Functional studies were performed to evaluate the role of SULF2 in the differentiation of HSCs into CAFs and elucidate the mechanism underlying CAF-mediated HCC growth. Mechanistic studies were performed using the chromatin immunoprecipitation, luciferase reporter, and RNA immunoprecipitation assays. The in vitro findings were verified using the nude HCC xenograft mouse model.

Results

The Cancer Genome Atlas (TCGA) database and IHC analyses revealed that the expression of CAF markers, which was positively correlated with that of SULF2 in the HCC tissues, predicted unfavorable postsurgical outcomes. Co-culturing HSCs with HCC cells expressing SULF2 promoted CAF differentiation. Additionally, CAFs repressed HCC cell apoptosis by activating the SDF-1/CXCR4/PI3K/AKT signaling pathway. Meanwhile, SULF2-induced CAFs promoted epithelial-to-mesenchymal transition (EMT) of HCC cells by modulating the SDF-1/CXCR4/OIP5-AS1/miR-153-3p/SNAI1 axis. Studies using HCC xenograft mouse models demonstrated that OIP5-AS1 induced EMT by upregulating SNAI1 and promoted HCC growth in vivo.

Conclusion

These data indicated that SULF2 secreted by the HCC cells induced the differentiation of HSCs into CAFs through the TGFβ1/SMAD3 signaling pathway. SULF2-induced CAFs attenuated HCC apoptosis by activating the SDF-1/CXCR4/PI3K/AKT signaling pathway and induced EMT through the SDF-1/CXCR4/OIP5-AS1/miR-153-3p/SNAI1 axis. This study revealed a novel mechanism involved in the crosstalk between HCC cells and CAFs in the tumor microenvironment, which can aid in the development of novel and efficient therapeutic strategies for primary liver cancer.

Syndecan-4 regulates extravillous trophoblast migration by coordinating protein kinase C activation

Extravillous trophoblast (EVT) invasion is an essential component of human placentation. Poor EVT invasion is associated with obstetrical complications including preeclampsia. Integration of cues from the extracellular environment is required for directional EVT invasion, but how EVTs coordinate responses to these cues is not well understood. Syndecan-4 (SDC4) is a transmembrane heparan sulfate proteoglycan that binds to, and modulates the activity of, many extracellular proteins implicated in placental development. Therefore, we determined the functional importance of SDC4 for EVT invasion. We found that SDC4 is expressed by a first trimester EVT line (HTR8), and in EVTs in placenta throughout pregnancy, with higher expression during early pregnancy than at term. Higher expression was also observed in placentas from preeclampsia compared to normotensive pregnancies. SDC4-deficient HTR8 EVTs exhibited reduced migration and Matrigel-based invasion, both under basal conditions and following exposure to basic fibroblast growth factor and heparin-binding epidermal growth factor. SDC4-deficient HTR8 EVTs also showed reduced protein kinase C-alpha (PKCα) and AKT phosphorylation. SDC4 directly bound to activated PKCα in EVTs, and inhibition of PKCα decreased EVT invasion and migration. Our findings reveal an essential role of SDC4 as a regulator of EVT motility, in part through coordination of PKCα activation.

Who climbs the tryptophan ladder? On the structure and function of the WSXWS motif in cytokine receptors and thrombospondin repeats

For decades, a spectacular structural motif has been the focus of research in two families of animal membrane proteins: the hematopoietic cytokine type I receptors (HCR) and the thrombospondin repeat type 1 (TSR-1) domain containing proteins. Although these families include some of the best-studied and pharmaceutically most interesting human proteins, the function of the motif remains elusive. Here we show that the molecular details of the motifs are the same; that it has arisen through convergent evolution, and we argue that the same ligand binding function is maintained and suggest that the ligand can be found in the extracellular matrix (ECM). We term the motif the tryptophan ladder and suggest a function based on a comparative analysis.

Smooth muscle specific deletion of Ndst1 leads to decreased vessel luminal area and no change in blood pressure in conscious mice

Heparan sulfate proteoglycans are abundant matrix and membrane molecules. Smooth muscle specific deletion of one heparan sulfate biosynthetic enzyme, N-deacetylase-N-sulfotransferase1 leads to decreased vascular smooth muscle cell proliferation, and vascular wall thickness. We hypothesized that this may lead to changes in blood pressure in conscious mice. Blood pressure was measured via telemetry in SM22αCre(+)Ndst1(-/-)(n = 4) and wild type (n = 8) mice. Aorta and thoracodorsal artery luminal area is significantly smaller in SM22αCre(+)Ndst1(-/-) (n = 4-8, P = 0.02, P = 0.0002) compared to wild type (n = 7) mice. Diurnal differences were observed in both cohorts for systolic, diastolic, mean arterial blood pressure, and heart rate (P < 0.001 from T test). No significant differences were found in the above parameters between the cohorts in either light or dark times using a linear mixed model. In conclusion, deletion of N-deacetylase-N-sulfotransferase1 in smooth muscle did not influence any of the blood pressure parameters measured despite significant decrease in aorta and thoracodorsal artery luminal area.

LC-MS(n) analysis of isomeric chondroitin sulfate oligosaccharides using a chemical derivatization strategy

Improved methods for structural analyses of glycosaminoglycans (GAGs) are required to understand their functional roles in various biological processes. Major challenges in structural characterization of complex GAG oligosaccharides using liquid chromatography-mass spectrometry (LC-MS) include the accurate determination of the patterns of sulfation due to gas-phase losses of the sulfate groups upon collisional activation and inefficient on-line separation of positional sulfation isomers prior to MS/MS analyses. Here, a sequential chemical derivatization procedure including permethylation, desulfation, and acetylation was demonstrated to enable both on-line LC separation of isomeric mixtures of chondroitin sulfate (CS) oligosaccharides and accurate determination of sites of sulfation by MS(n). The derivatized oligosaccharides have sulfate groups replaced with acetyl groups, which are sufficiently stable to survive MS(n) fragmentation and reflect the original sulfation patterns. A standard reversed-phase LC-MS system with a capillary C18 column was used for separation, and MS(n) experiments using collision-induced dissociation (CID) were performed. Our results indicate that the combination of this derivatization strategy and MS(n) methodology enables accurate identification of the sulfation isomers of CS hexasaccharides with either saturated or unsaturated nonreducing ends. Moreover, derivatized CS hexasaccharide isomer mixtures become separable by LC-MS method due to different positions of acetyl modifications.

Progesterone induction of chondroitin sulfate proteoglycan aggrecan expression in human endometrial epithelial cells

Chondroitin sulfate (CS) is the most abundant glycosaminoglycan species in the human endometrium, but the expression profile of CS proteoglycans (PGs) in this mucosal tissue remains fully undetermined. In this study, we aimed to clarify the expression of CSPGs including aggrecan, neurocan, melanoma-associated CSPG, neuroglycan C, and brevican in the human cycling endometrium. By reverse transcription-polymerase chain reaction, the gene transcripts for aggrecan core protein were detected in all samples examined, while other CSPGs were not. Western blotting showed the immunoreactivity for aggrecan core protein at approximately 370 kDa size after enzymatic digestion of CS-A and CS-C side chains. The expression level of aggrecan core protein was significantly higher in the secretory phase than in the proliferative phase. The immunostaining for aggrecan was detected in the endometrial microvascular endothelium throughout the menstrual cycle. The immunostaining in the glandular epithelium was faint during the proliferative and early secretory phase, but distinct during the mid-to-late-secretory phase. Progesterone, but not 17β-estradiol, induced aggrecan core protein expression in cultured endometrial epithelial cells. The endometrial expression pattern of aggrecan was distinct from that of other known CSPGs, suggesting the unique role of this proteoglycan at the implantation site.

Higher expression of vascular endothelial growth factor (VEGF) and its receptor VEGFR-2 (Flk-1) and metalloproteinase-9 (MMP-9) in a rat model of peritoneal endometriosis is similar to cancer diseases

Background

Endometriosis is a common disease characterized by the presence of a functional endometrium outside the uterine cavity, causing pelvic pain, dysmenorrheal, and infertility. This disease has been associated to development of different types of malignancies; therefore new blood vessels are essential for the survival of the endometrial implant. Our previous observations on humans showed that angiogenesis is predominantly found in rectosigmoid endometriosis, a deeply infiltrating disease. In this study, we have established the experimental model of rat peritoneal endometriosis to evaluate the process of angiogenesis and to compare with eutopic endometrium.

Methods

We have investigated the morphological characteristics of these lesions and the vascular density, VEGF and its receptor Flk-1 and MMP-9 expression, and activated macrophage distribution, using immunohistochemistry and RT-PCR.

Results

As expected, the auto-transplantation of endometrium pieces into the peritoneal cavity is a well-established method for endometriosis induction in rats. The lesions were cystic and vascularized, and demonstrated histological hallmarks of human pathology, such as endometrial glands and stroma. The vascular density and the presence of VEGF and Flk-1 and MMP-9 were significantly higher in endometriotic lesions than in eutopic endometrium, and confirmed the angiogenic potential of these lesions. We also observed an increase in the number of activated macrophages (ED-1 positive cells) in the endometriotic lesions, showing a positive correlation with VEGF.

Conclusion

The present endometriosis model would be useful for investigation of the mechanisms of angiogenesis process involved in the peritoneal attachment of endometrial cells, as well as of the effects of therapeutic drugs, particularly with antiangiogenic activity.

Heparin: an intervenor in cell communication

It was nearly 100 years since heparin was discovered, but the role of this widely used anticoagulant is still remarkably thought provoking now. During pathological processes such as atherosclerosis, inflammation, cancer and infection, phenomena of cell adhesion are ubiquitous and complicated. Heparin exerts anti-adhesion activity appearing as a common mechanism of its potential polypharmacology in those diseases. Furthermore, heparin can bind a variety of signalling molecules such as growth factors, cell surface proteins of pathogens and most notably, cell adhesion molecules. These signalling molecules are involved in cell communication, acting as ligands, receptors and second messengers. Considering that heparan sulphate glycosaminoglycan is increasingly recognized as a key mediator in many cellular processes, the structural similarity with heparan sulphate suggests that heparin is a multifunctional intervenor in cell communication.

Comparative aspects of implantation

Uterine receptivity to implantation of blastocysts in mammals includes hatching from zona pellucida, precontact with uterine luminal (LE) and superficial glandular (sGE) epithelia and orientation of blastocyst, apposition between trophectoderm and uterine LE and sGE, adhesion of trophectoderm to uterine LE/sGE, and, in some species, limited or extensive invasion into the endometrial stroma and induction of decidualization of stromal cells. These peri-implantation events are prerequisites for pregnancy recognition signaling, implantation, and placentation required for fetal-placental growth and development through the remainder of pregnancy. Although there is a range of strategies for implantation in mammals, a common feature is the requirement for progesterone (P(4)) to downregulate expression of its receptors in uterine epithelia and P(4) prior to implantation events. P(4) then mediates its effects via growth factors expressed by stromal cells in most species; however, uterine luminal epithelium may express a growth factor in response to P(4) and/or estrogens in species with a true epitheliochorial placenta. There is also compelling evidence that uterine receptivity to implantation involves temporal and cell-specific expression of interferon (IFN)-stimulated genes that may be induced directly by an IFN or induced by P(4) and stimulated by an IFN. These genes have many roles including nutrient transport, cellular remodeling, angiogenesis and relaxation of vascular tissues, cell proliferation and migration, establishment of an antiviral state, and protection of conceptus tissues from challenges by the maternal immune cells.

Agrin pathway is controlled by leukemia inhibitory factor (LIF) in murine implantation

Agrin is the heparan sulfate proteoglycan (HSPG) that is well known as the molecule that aggregates acetylcholine receptor (AChR) through muscle specific kinase (MuSK) and rapsyn at neuromuscular junctions. HSPGs are spatiotemporally expressed in embryonic and maternal tissues during implantation. The present study examined the role of agrin in the mouse embryo using leukemia inhibitory factor (LIF)-deficient mice, which show complete sterility. Agrin was detected widely in the cytoplasm of uterine luminal epithelial cells at the third day of pregnancy (Day 3) and Day 4. At Day 5, agrin moved to the apical surface of the luminal epithelium. This migration was not found in LIF-deficient mice. AChR was also found in the apical surface of the uterine epithelium at Day 4 and Day 5 in normal mice. LIF-deficient mice did not show this pattern of expression. Only nAChR b1 subunit mRNA was increased at Day 5 in normal mice. Furthermore, acetylcholinesterase was active in the uterine stroma of normal mice throughout the implantation period and was exclusively active in the uterine epithelium at Day 4. Taken together, agrin signaling was activated in the uterus during embryo implantation in the mice. Here, we suggest that the agrin pathway is involved in closure of the uterine epithelium toward placentation.

Composition of sulfated glycosaminoglycans and immunodistribution of chondroitin sulfate in deeply infiltrating endometriosis affecting the rectosigmoid

The composition of sulfated glycosaminoglycans (GAGs) and the tissue distribution of chondroitin sulfate (CS) were analyzed in deeply infiltrating endometriosis (DIE) of rectosigmoid, using metachromatic staining, and biochemical analysis employing electrophoresis before and after specific enzymatic or chemical degradations, and immunostaining with an antibody against CS. The sulfated GAGs were characterized as dermatan sulfate (DS), heparan sulfate (HS) and CS; and DS strongly predominated compared to HS and CS. Immunostaining procedures showed that CS was concentrated in the endometriosis foci, distributed throughout the stroma around the glands. This is the first report describing the composition of sulfated GAGs and the tissue location of CS in DIE by means of histochemical, biochemical and immunohistochemical analyses. These results confirmed that in DIE of rectosigmoid, as in eutopic endometrium [Nasciutti, L.E., Ferrari, R., Berardo, P.T., Souza, M.L.S., Takiya, C.M., Borojevic, R., Abrao, M.S., Silva, L.C.F., 2006. Distribution of chondroitin sulfate in human endometrium. Micron 37, 544-550], CS was the dominant sulfated GAG in stroma of the lesion foci.

Regulated adhesion as a driving force of gastrulation movements

Recent data have reinforced the fundamental role of regulated cell adhesion as a force that drives morphogenesis during gastrulation. As we discuss, cell adhesion is required for all modes of gastrulation movements in all organisms. It can even be instructive in nature, but it must be tightly and dynamically regulated. The picture that emerges from the recent findings that we review here is that different modes of gastrulation movements use the same principles of adhesion regulation, while adhesion molecules themselves coordinate the intra- and extracellular changes required for directed cell locomotion.

Dermatan sulfate proteoglycan biglycan as a potential selectin L/CD44 ligand involved in selective recruitment of peripheral blood CD16(-) natural killer cells into human endometrium

Unique CD16(-) NK cells acutely increase in the human uterine endometrium after ovulation. The origin of these NK cells remains unknown, but they may be recruited selectively from the circulation. Proteoglycans and their glycosaminoglycan side-chains expressed on endometrial microvascular endothelial cells play a key role in lymphocyte tethering/rolling, the initial step of lymphocyte extravasation. In this study, we sought for the potential proteoglycans involved in tethering/rolling of peripheral blood CD16(-) NK cells on endometrial microvascular endothelial cells. As compared with CD16(+) NK cells and non-NK cells, enriched peripheral blood CD16(-) NK cells bound preferably to immobilized glycosaminoglycans except for keratan sulfate. CD16(-) NK cells bound maximally to dermatan sulfate (DS), which was diminished by enzymatic pretreatment with dermatanase and chondroitinase ABC, but not with chondroitinase ACII. The binding capacity of CD16(-) NK cells to DS was attenuated by blocking antibodies against selectin L and CD44 or pretreatment of CD16(-) NK cells with IL-15. Of three known DS proteoglycans, biglycan and decorin but not epiphycan were expressed in the human cycling endometrium. In the endometrial microvessels, the immunoreactivity for biglycan was greater in the secretory phase than in the proliferative phase, and there was little, if any, immunoreactivity for decorin throughout the menstrual cycle. The ovarian steroid progesterone enhanced biglycan expression in cultured human uterine microvascular endothelial cells. These findings demonstrated that DS proteoglycan biglycan is a potential selectin L/CD44 ligand involved in tethering/rolling of peripheral blood CD16(-) NK cells on endometrial microvascular endothelial cells.