Fibulin-5 expression in the human placenta

Quantitative analysis of the serum proteome during early pregnancy in mares

Equine pregnancy is currently diagnosed by rectal palpation, ultrasonographic examination, or by measuring changes in hormones in the blood. In the present study, we identified proteins that are differentially expressed in the sera of early pregnant and non-pregnant mares in order to develop a novel method for diagnosing equine pregnancy. Serum samples were obtained from 18 adult mares, pregnancy at day 32 after ovulation (n = 9) and in diestrus (n = 9). Proteomic analysis of the samples was conducted using liquid chromatography-electrospray ionization-tandem mass spectrometry. We identified 467 proteins from a total of 3514 peptides. Thirty-two proteins (15 upregulated and 17 downregulated) were significantly differentially expressed between the two groups. The Gene Ontology enrichment analysis revealed that they are related to extracellular matrix assembly, blood coagulation, and hemostasis, and the prominent molecular functions were integrin binding, cell adhesion molecule binding, and glycine C-acetyltransferase activity. The pathway analysis of Kyoto Encyclopaedia of Genes and Genomes showed that the top three pathways identified were glycine, serine, and threonine metabolism; cysteine and methionine metabolism; and ether lipid metabolism. The selected five serum proteins were newly potential candidates for pregnancy diagnosis in mares.

An increase in elastogenic components in the placental villi of women with chronic venous disease during pregnancy is associated with decreased EGFL7 expression level

Chronic venous disease (CVD) is the response to a series of hemodynamic changes in the venous system and the onset of this disease is often triggered by pregnancy. Placental tissue is particularly sensitive to the characteristic changes which occurs in venous hypertension. In this regard, changes in the extracellular matrix (ECM), that occur to adapt to this situation, are fundamental to controlling elastogenesis. Therefore, the aim of the present study was to analyze the changes that occur in the mRNA and protein expression level of proteins related to elastogenesis in the placental villi of women diagnosed with CVD, in the third trimester of pregnancy. An observational, analytical and prospective cohort study was conducted, in which the placenta from 62 women with CVD were compared with that in placenta from 52 women without a diagnosis of CVD. Gene and protein expression levels were analyzed using reverse transcription-quantitative PCR and immunohistochemistry, respectively. The results showed a significant decrease in the gene and protein expression level of EGFL7 in the placental villi of women with CVD. By contrast, significant increases in the gene and protein expression level of ECM-related proteins, such as tropoelastin, fibulin 4, fibrillin 1 and members of the lysyl oxidase family (LOX and LOXL-1) were also found in the placental villi of women with CVD. To the best of our knowledge, the results from the present study showed for the first time that CVD during pregnancy was associated with changes in the mRNA and protein expression level in essential components of the EGFL7-modulated elastogenesis process in placental villi.

Potential SARS-CoV-2 interactions with proteins involved in trophoblast functions - An in-silico study

BACKGROUND

Though a large number of pregnant females have been affected by COVID-19, there is a dearth of information on the effects of SARS-CoV-2 infection on trophoblast function. We explored in silico, the potential interactions between SARS-CoV-2 proteins and proteins involved in the key functions of placenta.

METHODS

Human proteins interacting with SARS-CoV-2 proteins were identified by Gordon et al. (2020). Genes that are upregulated in trophoblast sub-types and stages were obtained by gene-expression data from NCBI-GEO and by text-mining. Genes altered in pathological states like pre-eclampsia and gestational diabetes mellitus were also identified. Genes crucial in placental functions thus identified were compared to the SARS-CoV-2 interactome for overlaps. Proteins recurring across multiple study scenarios were analyzed using text mining and network analysis for their biological functions.

RESULTS

The entry receptors for SARS-CoV-2 - ACE2 and TMPRSS2 are expressed in placenta. Other proteins that interact with SARS-CoV-2 like LOX, Fibulins-2 and 5, NUP98, GDF15, RBX1, CUL3, HMOX1, PLAT, MFGE8, and MRPs are vital in placental functions like trophoblast invasion and migration, syncytium formation, differentiation, and implantation. TLE3, expressed across first trimester placental tissues and cell lines, is involved in formation of placental vasculature, and is important in SARS-CoV (2003) budding and exit from the cells by COPI vesicles.

CONCLUSION

SARS-CoV-2 can potentially interact with proteins having crucial roles in the placental function. Whether these potential interactions identified in silico have effects on trophoblast functions in biological settings needs to be addressed by further in vitro and clinical studies.

The role of extracellular matrix in normal and pathological pregnancy: Future applications of microphysiological systems in reproductive medicine

IMPACT STATEMENT

Extracellular matrix in the womb regulates the initiation, progression, and completion of a healthy pregnancy. The composition and physical properties of extracellular matrix in the uterus and at the maternal-fetal interface are remodeled at each gestational stage, while maladaptive matrix remodeling results in obstetric disease. As in vitro models of uterine and placental tissues, including micro-and milli-scale versions of these organs on chips, are developed to overcome the inherent limitations of studying human development in vivo, we can isolate the influence of cellular and extracellular components in healthy and pathological pregnancies. By understanding and recreating key aspects of the extracellular microenvironment at the maternal-fetal interface, we can engineer microphysiological systems to improve assisted reproduction, obstetric disease treatment, and prenatal drug safety.

Pregnancy-induced Cardiovascular Pathologies: Importance of Structural Components and Lipids

Pregnancy leads to adaptations for maternal and fetal energy needs. The cardiovascular system bears the brunt of the adaptations as the heart and vessels enable nutrient supply to maternal organs facilitated by the placenta to the fetus. The components of the cardiovascular system are critical in the balance between maternal homeostatic and fetus driven homeorhetic regulation. Since lipids intersect maternal cardiovascular function and fetal needs with growth and in stress, factors affecting lipid deposition and mobilization impact risk outcomes. Here, the cardiovascular components and functional derangements associated with cardiovascular pathology in pregnancy, vis-à-vis lipid deposition, mobilization and maternal and/or cardiac and fetal energy needs are detailed. Most reports on the components and associated pathology in pregnancy, are on derangements affecting the extracellular matrix and epicardial fat, followed by the endothelium, vascular smooth muscle, pericytes and myocytes. Targeted studies on all cardiovascular components and pathological outcomes in pregnancy will enhance targeted interventions.

Fibulin-5 is upregulated in decidualized human endometrial stromal cells and promotes primary human extravillous trophoblast outgrowth

Interactions between the highly invasive trophoblasts and the maternal uterine decidual extracellular matrix (ECM) are crucial in the determination of a successful pregnancy. Fibulin-5 (FBLN5) is a member of the fibulin family that alters cell adhesive and invasive properties and is expressed in human villous cytotrophoblasts. We aimed to determine the expression and immunolocalization of FBLN5 in human first trimester decidua and examine the effect of FBLN5 in trophoblast invasion in vitro using a first trimester placental villous outgrowth assay. We demonstrated that FBLN5 mRNA expression is upregulated in response to cAMP-mediated decidualization of primary human endometrial stromal cells, although FBLN5 itself does not enhance decidualization. We reported for the first time, FBLN5 protein production in first trimester decidual cells and also co-localization to HLAG-positive EVTs in first trimester decidua. Consequently, we investigated the effects of exogenous FBLN5 on placental villous outgrowth in vitro and demonstrated that FBLN5 promotes EVT migration/invasion. This is the first study to identify FBLN5 in decidualized human endometrial stromal cells, first trimester decidua and EVT and determine a functional role for FBLN5 in human EVTs, suggesting that decidual and or EVT-derived FBLN5 regulates EVT invasion and placentation in women.

Placental fractalkine mediates adhesion of THP-1 monocytes to villous trophoblast

The chemokine fractalkine (CX3CL1) recently attracted increasing attention in the field of placenta research due to its dual nature, acting both as membrane-bound and soluble forms. While the membrane-bound form mediates flow-resistant adhesion of leukocytes to endothelial and epithelial cells via its corresponding receptor CX3CR1, the soluble form arises from metalloprotease-dependent shedding and bears chemoattractive activity for monocytes, natural killer cells and T cells. In human placenta, fractalkine is expressed at the apical microvillous plasma membrane of the syncytiotrophoblast, which may enable close physical contact with circulating maternal leukocytes. Based on these observations, we tested the hypothesis that fractalkine mediates adhesion of monocytes to the villous trophoblast. Forskolin-induced differentiation and syncytialization of the trophoblast cell line BeWo was accompanied with a substantial upregulation in fractalkine expression and led to increased adhesion of the monocyte cell line THP-1, which preferentially bound to syncytia. Blocking as well as silencing of the fractalkine receptor CX3CR1 proved involvement of the fractalkine/CX3CR1 system in adherence of THP-1 monocytes to villous trophoblast. Pre-incubation of THP-1 monocytes with human recombinant fractalkine as well as silencing of CX3CR1 expression in THP-1 monocytes significantly impaired their adherence to BeWo cells and primary term trophoblasts. The present study suggests fractalkine as another candidate among the panel of adhesion molecules enabling stable interaction between leukocytes and the syncytiotrophoblast.

The comparison of endogenous angiogenesis inhibitors in normotensive and preeclamptic placentas: an immunohistochemical study

OBJECTIVE

Recently, it has been reported that endogenous angiogenesis inhibitors play a key role in the pathophysiology of preeclampsia. Thrombospondin-1, angiostatin and vasostatin are endogenous angiogenesis inhibitors and so far have not been shown in placenta at the immunohistochemical level. The aim of this study was to compare staining patterns of these endogenous angiogenesis inhibitors immunohistochemically in placentas of preeclamptic and normotensive pregnant women.

METHODS

Into the study, placentas from 20 preeclamptic and 20 normotensive pregnant women were included. Central and peripheral tissues were taken from both sides of placentas. Paraffin tissue blocks were prepared and stained for immunohistochemical analysis. Slides were evaluated for syncytiotrophoblasts, cytotrophoblasts, extra-villous throphoblasts and decidual cells. The degree of staining of slides were classified as negative, weak, moderate and strong.

RESULTS

Samples from preeclamptic patients were compared with those of normotensive. Staining of thrombospondin-1 was observed to increase in decidual cells, syncytiotrophoblasts in chorionic and stem villi and stroma of stem villi. Increased staining of thrombospondin-1 was only significant in the amniotic epithelium of the central sections. In addition, increased staining intensity of angiostatin was detected in the amniotic epithelium and chorionic plate of central sections of placenta. In peripheral sections, staining of angiostatin also increased in decidual cells but decreased in chorionic plate. Vasostatin staining in decidual cells, decidual stroma and chorionic villous stroma from peripheral sections decreased, but any difference was not observed in the central sections.

CONCLUSION

Our results suggest that thrombospondin-1, angiostatin and vasostatin may play a role in the pathophysiology of preeclampsia. Further molecular studies are required to understand this role.

Recent progress in histochemistry and cell biology

Studies published in Histochemistry and Cell Biology in the year 2011 represent once more a manifest of established and newly sophisticated techniques being exploited to put tissue- and cell type-specific molecules into a functional context. The review is therefore the Histochemistry and Cell Biology's yearly intention to provide interested readers appropriate summaries of investigations touching the areas of tissue biology, developmental biology, the biology of the immune system, stem cell research, the biology of subcellular compartments, in order to put the message of such studies into natural scientific-/human- and also pathological-relevant correlations.