Hyaluronate and CD44 expression patterns in the human placenta throughout pregnancy

Special Issue "Physiology and Pathophysiology of Placenta 2.0"

We are pleased to present this Special Issue of the International Journal of Molecular Sciences, entitled "Physiology and Pathophysiology of Placenta 2 [...].

Special Issue "Physiology and Pathophysiology of the Placenta"

The placenta is a transient but essential organ for normal in utero development, playing several essential functions in normal pregnancy [...].

Mechanisms of action of mineral fibres in a placental syncytiotrophoblast model: An in vitro toxicology study

Asbestos has been widely used due to its unique characteristics. It is known that exposure to asbestos causes serious damage to health but one species, chrysolite, is still used because it is considered less toxic and not biopersistent in some countries. The aim of our study was to investigate if cellular process underlying the proliferation, differentiation and cell death of placental tissues could be modify in presence of asbestos fibres (50 μg/ml final concentration), long chrysolite fibres (CHR-L) and short chrysolite fibres (CHR-S), using BeWo cell line, an in vitro model that mimics the syncytiotrophoblast (STB), the outer layer of placental villi. Our data demonstrated that none of the fibres analysed alter syncytiotrophoblast formation but all of them induce ROS formation and reduced cell proliferation. Moreover, we showed that only CHR-L fibre induced was able to induce irreversible DNA alterations that carried cells to apoptosis. In fact, BeWo cells exposed to CHR-L fibre showed a significant increase in cleaved CASP3 protein, a marker of apoptosis. These data suggest that CHR-L may induce death of the placental villi leading to impaired placental development. The impairment of placental development is the basis of many gestational pathologies such as preeclampsia and intrauterine growth retardation. Since these pathologies are very dangerous for foetal and maternal life, we suggest to the gynaecologists to carefully evaluate the area of maternal residence, the working environment, the food used, and the materials used daily to avoid contact with these fibres as much as possible.

Physiology and Pathophysiology of the Placenta

We are pleased to present this Special Issue of the International Journal of Molecular Sciences, entitled "Physiology and Pathophysiology of Placenta" [...].

Proteoglycans: Systems-Level Insight into Their Expression in Healthy and Diseased Placentas

Proteoglycan macromolecules play key roles in several physiological processes (e.g., adhesion, proliferation, migration, invasion, angiogenesis, and apoptosis), all of which are important for placentation and healthy pregnancy. However, their precise roles in human reproduction have not been clarified. To fill this gap, herein, we provide an overview of the proteoglycans' expression and role in the placenta, in trophoblast development, and in pregnancy complications (pre-eclampsia, fetal growth restriction), highlighting one of the most important members of this family, syndecan-1 (SDC1). Microarray data analysis showed that of 34 placentally expressed proteoglycans, SDC1 production is markedly the highest in the placenta and that SDC1 is the most upregulated gene during trophoblast differentiation into the syncytiotrophoblast. Furthermore, placental transcriptomic data identified dysregulated proteoglycan genes in pre-eclampsia and in fetal growth restriction, including SDC1, which is supported by the lower concentration of syndecan-1 in maternal blood in these syndromes. Overall, our clinical and in vitro studies, data analyses, and literature search pointed out that proteoglycans, as important components of the placenta, may regulate various stages of placental development and participate in the maintenance of a healthy pregnancy. Moreover, syndecan-1 may serve as a useful marker of syncytialization and a prognostic marker of adverse pregnancy outcomes. Further studies are warranted to explore the role of proteoglycans in healthy and complicated pregnancies, which may help in diagnostic or therapeutic developments.

Absorption, distribution, metabolism and excretion of hyaluronic acid during pregnancy: a matter of molecular weight

INTRODUCTION

For many years hyaluronic acid (HA) was mainly used for its hydrating properties. However, new applications have recently arisen, considering the biological properties of HA and its molecular weight. Clinical application of low molecular weight HA (LMW-HA) initially was supported by specific absorption data. The identification of high molecular weight HA (HMW-HA) absorption pathways and the knowledge of its physiological role allowed to evaluate its clinical application. Based on the immunomodulatory properties of HMW-HA and its physiological involvement as signaling molecule, pregnancy represents an interesting context of application.

AREA COVERED

This expert opinion includes in-vitro, in-vivo, ex-vivo and clinical studies on gestational models. It provides an overview of the physiological and the therapeutic role of HMW-HA in pregnancy starting from its metabolism. Indeed, HMW-HA is widely involved in several physiological processes as implantation, immune response, uterine quiescence and cervical remodeling, and therefore is an essential molecule for a successful pregnancy.

EXPERT OPINION

Available evidence suggests that HMW-HA administration can support physiological pregnancy, favoring blastocyst adhesion and development, preventing miscarriage and pre-term birth. For this reason, supplementation in pregnancy should be evaluated.

Mitochondrial role in adaptive response to stress conditions in preeclampsia

Preeclampsia (PE) is a pregnancy-specific syndrome, characterized in general by hypertension with proteinuria or other systemic disturbances. PE is the major cause of maternal and fetal morbidity and mortality worldwide. However, the etiology of PE still remains unclear. Our study involved 38 patients: 14 with uncomplicated pregnancy; 13 with early-onset PE (eoPE); and 11 with late-onset PE (loPE). We characterized the immunophenotype of cells isolated from the placenta and all biopsy samples were stained positive for Cytokeratin 7, SOX2, Nestin, Vimentin, and CD44. We obtained a significant increase in OPA1 mRNA and protein expression in the eoPE placentas. Moreover, TFAM expression was down-regulated in comparison to the control (p < 0.01). Mitochondrial DNA copy number in eoPE placentas was significantly higher than in samples from normal pregnancies. We observed an increase of maximum coupled state 3 respiration rate in mitochondria isolated from the placenta in the presence of complex I substrates in the eoPE group and an increase of P/O ratio, citrate synthase activity and decrease of Ca(2+)-induced depolarization rate in both PE groups. Our results suggest an essential role of mitochondrial activity changes in an adaptive response to the development of PE.

Localisation and endocrine control of hyaluronan synthase (HAS) 2, HAS3 and CD44 expression in sheep granulosa cells

The aim of the present study was to investigate the hormonal regulation of hyaluronan (HA) components in sheep granulosa cells. HA components are present in the reproductive tract and have a range of physical and signalling properties related to reproductive function in several species. First, abattoir-derived ovaries of sheep were used to determine the localisation of HA synthase (HAS) 1–3 and CD44 proteins in antral follicles. Staining for HAS1–3 and CD44 proteins was most intense in the granulosa layer. Accordingly, the expression of HAS2, HAS3 and CD44 mRNA was measured in cultured granulosa cells exposed to 0–50 ng mL–1 of 17β-oestradiol and different combinations of oestradiol, gonadotropins, insulin-like growth factor (IGF)-1 and insulin for 48–96 h (1 ng mL–1 FSH, 10 ng mL–1 insulin, 10 ng mL–1 IGF-1, 40 ng mL–1 E2 and 25 ng mL–1 LH.). mRNA expression was quantified by real-time polymerase chain reaction using a fold induction method. The results revealed that the hormones tested generally stimulated mRNA expression of the genes of interest in cultured granulosa cells. Specifically, oestradiol, when combined with IGF-1, insulin and FSH, stimulated HAS2 mRNA expression. Oestradiol and LH had synergistic effects in increasing HAS3 mRNA expression. In conclusion, we suggest that the hormones studied differentially regulate HAS2, HAS3 and CD44 in ovine granulosa cells in vitro. Further work is needed to address the signalling pathways involved.

Role of mouse Wdr13 in placental growth; a genetic evidence for lifetime body weight determination by placenta during development

Placental development is essential for implantation and growth of foetus in the uterus of eutherian mammals. Numerous growth factors are responsible for placental development and cell lineage differentiation. Gene knockout mice have shown role of various genes in the placenta. Here using Wdr13 knockout mice, we show that this gene is important for proper placental development. Wdr13, a X-linked gene, expresses in multiple trophoblast cell types of placenta and the mutant placenta had reduced size after 17.5 dpc due to reduction of junctional zone (JZ) and labyrinth zone (LZ). We observed reduction in levels of angiopoietin-2 and cd44 mRNA in Wdr13 mutant placenta as compared to that in the wild type. Our findings show that Wdr13 is required for normal placental development and cell differentiation. Wdr13 heterozygous female placenta when the mutant allele was of maternal origin showed similar defects as those in case of Wdr13 null placenta. Using two types of heterozygous females carrying either maternally and paternally derived mutant Wdr13 allele we provide genetic evidence that development of placenta determines body weight of mice for the entire life.

Hyaluronan-CD44 interaction promotes growth of decidual stromal cells in human first-trimester pregnancy

Hyaluronan (HA) and its receptor CD44 are expressed at the maternal-fetal interface, but its role in early pregnancy remains unclear. Here, we found that primary decidual stromal cells (DSCs) continuously secreted HA and expressed its receptor CD44. Pregnancy-associated hormones up-regulated HA synthetase (HAS) 2 transcription and HA release from DSCs. High molecular weight-HA (HMW-HA), but not medium molecular weight (MMW-HA) or low molecular weight (LMW-HA), promoted proliferation and inhibited apoptosis of DSCs in a CD44-dependent manner. The in-cell Western analysis revealed HMW-HA activated PI3K/AKT and mitogen-activated protein kinase (MAPK)/ERK1/2 signaling pathways time-dependently. Blocking these pathways by specific inhibitor LY294002 or U0126 abrogated HMW-HA-regulated DSc proliferation and apoptosis. Finally, we have found that HA content, HA molecular weight, HAS2 mRNA level, and CD44 expression were significantly decreased in DSCs from unexplained miscarriage compared with the normal pregnancy. Collectively, our results indicate that higher level and greater molecular mass of HA at maternal-fetal interface contributes to DSc growth and maintenance of DSCs in human early pregnancy.

Hyaluronan up-regulates growth and invasion of trophoblasts in an autocrine manner via PI3K/AKT and MAPK/ERK1/2 pathways in early human pregnancy

INTRODUCTION

As one of the key molecules in the extracellular matrix in human conceptus, hyaluronan (HA) has been receiving particular attention. Here, we have investigated the expression and regulation of different molecular weight HA on the biological behaviors of primary human trophoblasts during the first trimester of pregnancy.

METHODS

The expression of HA and HA synthetase (HAS) by human first trimester trophoblasts was analyzed in placentae from normal pregnancy or miscarriage by immunochemistry and real-time RT-PCR, respectively. ELISA was used to measure the secretion of HA by primary trophoblasts. The effects of HA on the proliferation, apoptosis and invasiveness of trophoblasts were examined. We also investigated the signaling pathways involved in HA activation in human trophoblasts.

RESULTS

The higher HAS2 expression and HA secretion were observed in normal villi than that of miscarriage, and the primary trophoblasts secreted HA continuously. High molecular weight HA (HMW-HA) and medium molecular weight HA (MMW-HA) promoted proliferation and invasiveness while inhibited apoptosis of trophoblasts. However, low molecular weight HA (LMW-HA) had no obvious effect on the growth or invasiveness of human trophoblasts. In addition, HMW-HA showed more efficiently than MMW-HA on the growth while MMW-HA displayed a more obvious effect on the invasiveness of trophoblasts than HMW-HA. HMW-HA activated PI3K/AKT and MAPK/ERK1/2 signaling pathways in trophoblasts. Blocking PI3K/AKT or MAPK/ERK1/2 signaling inhibited the HA-upregulated growth and invasiveness of human trophoblasts.

CONCLUSION

Our results suggest that higher level and greater molecular mass of HA can promote trophoblast growth and invasion in an autocrine manner, which was beneficial to placentation and maintenance of human early pregnancy.

Hyaluronan substratum induces multidrug resistance in human mesenchymal stem cells via CD44 signaling

Little information is available concerning multidrug resistance (MDR) in mesenchymal stem cells, although several studies have reported that MDR is associated with hyaluronan in neoplastic cells. We have evaluated whether a hyaluronan-coated surface modulates MDR in placenta-derived human mesenchymal stem cells (PDMSCs). We have found that PDMSCs cultured on a tissue-culture polystyrene surface coated with 30 microg/cm(2) hyaluronan are more resistant than control PDMSCs to doxorubicin. Inhibiting PI3K/Akt signaling has shown that the PI3K/Akt pathway modulates both P-glycoprotein activity and doxorubicin resistance. In addition, 10 microM verapamil dramatically suppresses the doxorubicin resistance induced by the hyaluronan-coated surface, indicating that P-glycoprotein activity is necessary for MDR. We have further found that PDMSCs treated with CD44 small interfering RNA (siRNA) and grown on a polystyrene surface coated with 30 microg/cm(2) hyaluronan have fewer P-glycoprotein(+) cells and lower CD44 expression levels (less than 60% in both cases) than PDMSCs not treated with CD44 siRNA and grown on the hyaluronan-coated surface. Moreover, treatment with CD44 siRNA suppresses the hyaluronan-substratum-induced doxorubicin resistance. We conclude that a hyaluronan substratum induces MDR in PDMSCs through CD44 signaling.

Expression of CD44 adhesion molecules on human placentae

OBJECTIVE

This study was performed to characterize CD44 expression in human placentae.

STUDY DESIGN

We conducted reverse transcriptase polymerase chain reaction (RT-PCR) analyses of CD44H (hematopoietic form, also called CD44s) and CD44R1 (epithelial form) in 14 normal term placentae, and immunohistochemical analysis of CD44H and CD44v6 in 31 placentae (25 term and 6 first-trimester).

RESULTS

All 14 term placentae expressed CD44H (double bands) suggesting expression of alternative isoforms on the placentae. CD44R1 was expressed on 3 of 14 (21.4%) term placentae. Immunohistochemical analysis revealed expression of CD44H in all the placentae examined. However, positive staining for CD44v6 was observed in 3 of 6 (50%) first-trimester and only 6 of 25 (24%) term placentae showing decreased expression on term placentae. Positive staining for CD44v6 was observed on the trophoblast surface of immature villi especially in the sub-chorionic area where hypoxic conditions prevail.

CONCLUSION

These results suggest that CD44 splicing variants might play a role in the invasion of trophoblast into maternal tissue in early pregnancy.

Detection of the Hyaluronan Receptor CD44 in the Bovine Oviductal Epithelium

Hyaluronan is involved in fundamental reproductive events such as sperm storage in the female reproductive tract, fertilization, and early embryo development, these functions are presumably mediated by its major cell surface receptor, CD44. The present study was conducted to investigate the presence and localization of CD44 in the bovine oviductal epithelium, using immunohistochemical and Western blot methods on tissue sections and epithelial cell extracts collected from the uterotubal junction (UTJ), isthmus, and ampulla of animals in the oestrus or luteal phase of the oestrous cycle. While positive immunolabelling for CD44 was found on the ad-luminal surface and supra-nuclear region of epithelial cells in all tubal segments investigated, in the UTJ, there were epithelial cells in which the entire cytoplasm positively stained. We found no differences in terms of CD44-positive staining between the different stages of the oestrous cycle. Presence of CD44 was detected by Western blotting in the tubal epithelium as a single band at 200 kDa. Although it appeared in all tubal segments, the expression of CD44 protein was more accentuated in the sperm reservoir (UTJ) than in the other segments. This is the first time CD44 has been detected in the epithelium of the tubal sperm reservoir in cattle, suggesting a pathway for the action of hyaluronan in this segment.