Galectin-1-Related Modulation of Trophoblast Endothelial Interactions by Integrins α1 and β1

Current understanding of the pathogenesis of placenta accreta spectrum disorder with focus on mitochondrial function

AIM

The refinement of assisted reproductive technology, including the development of cryopreservation techniques (vitrification) and ovarian stimulation protocols, makes frozen embryo transfer (FET) an alternative to fresh ET and has contributed to the success of assisted reproductive technology. Compared with fresh ET cycles, FET cycles were associated with better in vitro fertilization outcomes; however, the occurrence of pregnancy-induced hypertension, preeclampsia, and placenta accreta spectrum (PAS) was higher in FET cycles. PAS has been increasing steadily in incidence as a life-threatening condition along with cesarean rates worldwide. In this review, we summarize the current understanding of the pathogenesis of PAS and discuss future research directions.

METHODS

A literature search was performed in the PubMed and Google Scholar databases.

RESULTS

Risk factors associated with PAS incidence include a primary defect of the decidua basalis or scar dehiscence, aberrant vascular remodeling, and abnormally invasive trophoblasts, or a combination thereof. Freezing, thawing, and hormone replacement manipulations have been shown to affect multiple cellular pathways, including cell proliferation, invasion, epithelial-to-mesenchymal transition (EMT), and mitochondrial function. Molecules involved in abnormal migration and EMT of extravillous trophoblast cells are beginning to be identified in PAS placentas. Many of these molecules were also found to be involved in mitochondrial biogenesis and dynamics.

CONCLUSION

The etiology of PAS may be a multifactorial genesis with intrinsic predisposition (e.g., placental abnormalities) and certain environmental factors (e.g., defective decidua) as triggers for its development. A distinctive feature of this review is its focus on the potential factors linking mitochondrial function to PAS development.

The universe of galectin-binding partners and their functions in health and disease

Galectins, a family of evolutionarily conserved glycan-binding proteins, play key roles in diverse biological processes including tissue repair, adipogenesis, immune cell homeostasis, angiogenesis, and pathogen recognition. Dysregulation of galectins and their ligands has been observed in a wide range of pathologic conditions including cancer, autoimmune inflammation, infection, fibrosis, and metabolic disorders. Through protein-glycan or protein-protein interactions, these endogenous lectins can shape the initiation, perpetuation, and resolution of these processes, suggesting their potential roles in disease monitoring and treatment. However, despite considerable progress, a full understanding of the biology and therapeutic potential of galectins has not been reached due to their diversity, multiplicity of cell targets, and receptor promiscuity. In this article, we discuss the multiple galectin-binding partners present in different cell types, focusing on their contributions to selected physiologic and pathologic settings. Understanding the molecular bases of galectin-ligand interactions, particularly their glycan-dependency, the biochemical nature of selected receptors, and underlying signaling events, might contribute to designing rational therapeutic strategies to control a broad range of pathologic conditions.

Human umbilical cord mesenchymal stem cell-derived extracellular vesicles loaded with TFCP2 activate Wnt/β-catenin signaling to alleviate preeclampsia

BACKGROUND

Failures in invasive extravillous trophoblasts (EVTs) migration into the maternal uterus have been noticed in preeclampsia (PE). Human umbilical cord mesenchymal stem cell (hUCMSC)-derived extracellular vesicles (EVs) have been highlighted for the role as a potential therapeutic method in PE. This study intends to investigate the mechanistic basis of hUCMSCs-derived EVs loaded with bioinformatically identified TFCP2 in the activities of EVTs of PE.

METHODS

Primary human EVTs were exposed to hypoxic/reoxygenation (H/R) to mimic the environment encountered in PE. The in vivo PE-like phenotypes were induced in mice by reduced uterine perfusion pressure (RUPP) surgery. CCK-8, Transwell and flow cytometry assays were performed to detect proliferation, migration, invasion and apoptosis of H/R-exposed EVTs. More importantly, EVs were extracted from hUCMSCs and transduced with ectopically expressed TFCP2, followed by co-culture with EVTs.

RESULTS

TFCP2 was found to be down-regulated in the preeclamptic placental tissues and in H/R-exposed EVTs. hUCMSCs-EVs loaded with TFCP2 activated the Wnt/β-catenin pathway, thereby promoting the proliferative, migratory, and invasive potential of EVTs. Furthermore, overexpression of TFCP2 alleviated PE-like phenotypes in mice, which was associated with activated Wnt/β-catenin pathway.

CONCLUSION

From our data we conclude that hUCMSCs-EVs overexpressing TFCP2 may be instrumental for the therapeutic targeting and clinical management of PE.

Early human trophoblast development: from morphology to function

Human pregnancy depends on the proper development of the embryo prior to implantation and the implantation of the embryo into the uterine wall. During the pre-implantation phase, formation of the morula is followed by internalization of blastomeres that differentiate into the pluripotent inner cell mass lineage, while the cells on the surface undergo polarization and differentiate into the trophectoderm of the blastocyst. The trophectoderm mediates apposition and adhesion of the blastocyst to the uterine epithelium. These processes lead to a stable contact between embryonic and maternal tissues, resulting in the formation of a new organ, the placenta. During implantation, the trophectoderm cells start to differentiate and form the basis for multiple specialized trophoblast subpopulations, all of which fulfilling specific key functions in placentation. They either differentiate into polar cells serving typical epithelial functions, or into apolar invasive cells that adapt the uterine wall to progressing pregnancy. The composition of these trophoblast subpopulations is crucial for human placenta development and alterations are suggested to result in placenta-associated pregnancy pathologies. This review article focuses on what is known about very early processes in human reproduction and emphasizes on morphological and functional aspects of early trophoblast differentiation and subpopulations.

Galectins in Early Pregnancy and Pregnancy-Associated Pathologies

Galectins are a family of conserved soluble proteins defined by an affinity for β-galactoside structures present on various glycoconjugates. Over the past few decades, galectins have been recognized as important factors for successful implantation and maintenance of pregnancy. An increasing number of studies have demonstrated their involvement in trophoblast cell function and placental development. In addition, several lines of evidence suggest their important roles in feto-maternal immune tolerance regulation and angiogenesis. Changed or dysregulated galectin expression is also described in pregnancy-related disorders. Although the data regarding galectins' clinical relevance are still at an early stage, evidence suggests that some galectin family members are promising candidates for better understanding pregnancy-related pathologies, as well as predicting biomarkers. In this review, we aim to summarize current knowledge of galectins in early pregnancy as well as in pregnancy-related pathologies.

Considerations to Model Heart Disease in Women with Preeclampsia and Cardiovascular Disease

Preeclampsia is a multifactorial cardiovascular disorder diagnosed after 20 weeks of gestation, and is the leading cause of death for both mothers and babies in pregnancy. The pathophysiology remains poorly understood due to the variability and unpredictability of disease manifestation when studied in animal models. After preeclampsia, both mothers and offspring have a higher risk of cardiovascular disease (CVD), including myocardial infarction or heart attack and heart failure (HF). Myocardial infarction is an acute myocardial damage that can be treated through reperfusion; however, this therapeutic approach leads to ischemic/reperfusion injury (IRI), often leading to HF. In this review, we compared the current in vivo, in vitro and ex vivo model systems used to study preeclampsia, IRI and HF. Future studies aiming at evaluating CVD in preeclampsia patients could benefit from novel models that better mimic the complex scenario described in this article.

Vascular mechanisms and molecular targets in hypertensive pregnancy and preeclampsia

Preeclampsia is a major complication of pregnancy manifested as hypertension and often intrauterine growth restriction, but the underlying pathophysiological mechanisms are unclear. Predisposing genetic and environmental factors cause placental maladaptations leading to defective placentation, apoptosis of invasive cytotrophoblasts, inadequate expansive remodeling of the spiral arteries, reduced uteroplacental perfusion pressure, and placental ischemia. Placental ischemia promotes the release of bioactive factors into the maternal circulation, causing an imbalance between antiangiogenic soluble fms-like tyrosine kinase-1 and soluble endoglin and proangiogenic vascular endothelial growth factor, placental growth factor, and transforming growth factor-β. Placental ischemia also stimulates the release of proinflammatory cytokines, hypoxia-inducible factor, reactive oxygen species, and angiotensin type 1 receptor agonistic autoantibodies. These circulating factors target the vascular endothelium, causing generalized endotheliosis in systemic, renal, cerebral, and hepatic vessels, leading to decreases in endothelium-derived vasodilators such as nitric oxide, prostacyclin, and hyperpolarization factor and increases in vasoconstrictors such as endothelin-1 and thromboxane A₂. The bioactive factors also target vascular smooth muscle and enhance the mechanisms of vascular contraction, including cytosolic Ca²⁺, protein kinase C, and Rho-kinase. The bioactive factors could also target matrix metalloproteinases and the extracellular matrix, causing inadequate vascular remodeling, increased arterial stiffening, and further increases in vascular resistance and hypertension. As therapeutic options are limited, understanding the underlying vascular mechanisms and molecular targets should help design new tools for the detection and management of hypertension in pregnancy and preeclampsia.

Calcium deficient placental growth restriction is mediated by an increase in non-invasive integrin α5 and β4 phenotype

OBJECTIVES

Integrins are cell adhesion receptors that participated in endovascular invasion by cytotrophoblasts in preeclampsia. This study aimed to investigate the effect of calcium on cellular pathways influencing the trophoblast integration into endothelial cellular networks in vitro.

STUDY DESIGN

Red fluorescent-labelled human uterine myometrial microvascular endothelial cells (UtMVECs) were seeded on Matrigel. Green fluorescent-labelled HTR-8/SVneo trophoblast cells were then co-cultured with endothelial cells in different concentrations of calcium for 24 h.

MAIN OUTCOME MEASURES

The calcium effects on HTR-8/SVneo cell integration were quantified by Image J. Quantitative PCR was performed to measure mRNA expression of integrins α1, α5, α6, β1 and β4. The concentrations of interleukin IL-6, matrix metalloproteinase-2 (MMP-2), MMP-9, PlGF and sFlt-1 in the conditioned medium were measured by ELISA while levels of cytokines IL-1β, IL-8, IL-10, TNF-α and INF-γ were assessed by magnetic Luminex assays™.

RESULTS

Both calcium depletion (0.4 mM) and low calcium (1.8 mM) groups demonstrated inhibited integration of trophoblast cells into endothelial cellular networks, compared with the normal calcium group (2.4 mM). The IL-6 production was reduced from conditioned media in both calcium depletion and low calcium groups. In calcium depletion group, mRNA expression of integrin α5 and β4 in trophoblasts was increased while integrin α1 was decreased.

CONCLUSIONS

The in vitro trophoblast cell integration into endothelial cellular networks could be modified by altering media calcium through integrin switch away from integrins α5 and β4 and towards integrin α1 which may be required for healthy early trophoblast integration.