Placental Dysplasia Research Articles

Abnormal placental development induced by repeated cesarean sections: Investigating an animal model of placenta accreta spectrum disorders.

Placenta accreta spectrum (PAS) is a serious condition associated with severe postpartum hemorrhage, leading to emergency hysterectomy. Research has predominantly focused on clinical diagnosis and the prevention of adverse maternal outcomes, but the underlying pathological mechanisms remain poorly understood, partly due to the limitations of animal models. In this study, we conducted up to three cesarean sections (CS) on full-term pregnant mice, since a history of multiple CS is an independent risk factor for PAS. We evaluated pregnancy outcomes, placental development, morphology, trophoblast invasion, and angiogenesis at the maternal-fetal interface to assess the impact of repeated CS. Following repeated CS, the model mice displayed adverse pregnancy outcomes, including placental dysplasia, incomplete remodeling of spiral arteries, deep trophoblast invasion at the maternal-fetal interface, and reduced placental perfusion. Additionally, the mice exhibited abnormal fetal development, imbalances in angiogenic and anti-angiogenic both within the placenta and in peripheral blood. The pathological phenotypes of placenta and adverse pregnancy outcomes observed in mice with a history of three CSs closely resemble the clinical features of PAS. This model offers a valuable tool for studying the pathogenesis of PAS and could serve as a foundation for the development of early prevention strategies.

CTNND1 affects trophoblast proliferation and specification during human embryo implantation.

The placenta, serving as the crucial link between maternal and infant, plays a pivotal role in maintaining a healthy pregnancy. Placental dysplasia can lead to various complications, underscoring the importance of understanding trophoblast lineage development. During peri-implantation, the trophectoderm (TE) undergoes differentiation into cytotrophoblast (CTB), syncytiotrophoblast (STB), and extravillous trophoblast (EVT). However, the specification and regulation of human trophoblast lineage during embryo implantation, particularly in the peri-implantation phase, remain to be explored. In this study, we employed a co-culture model of human endometrial cells and native embryos and analyzed the single-cell transcriptomic data of 491 human embryonic trophoblasts during E6 to E10 to identify the key regulatory factors and the lineage differentiation process during peri-implantation. Our data identified four cell subpopulations during the implantation, including a specific transitional state toward the differentiation in which the CTNND1, one crucial component of Wnt signaling pathway activated by cadherins, acted as a crucial factor. Knockdown of CTNND1 impacted the proliferative capacity of trophoblast stem cells (hTSCs), leading to early EVT-like differentiation. Intriguingly, ablation of CTNND1 compromised the terminal differentiation of hTSCs toward both STB or EVT in vitro. Those observations identified the role of cell adhesion-mediated Wnt signaling in hTSC self-renewal, as well as suggest that this signaling pathway controls a transitional state that is crucial for trophoblast lineage specification. These findings contribute valuable insights into trophoblast lineage dynamics and offer a reference for research on placental-related diseases.

N-acetylcysteine and Hydroxychloroquine Ameliorate ADMA-Induced Fetal Growth Restriction in Mice via Regulating Oxidative Stress and Autophagy.

Fetal growth restriction (FGR) seriously threatens perinatal health. The main cause of FGR is placental malperfusion, but the specific mechanism is still unclear, and there is no effective treatment for FGR. We constructed a FGR mouse model by adding exogenous asymmetric dimethylarginine (ADMA) through in vivo experiments and found that ADMA could cause placental dysplasia and induce the occurrence of FGR. Compared with the control group, reactive oxygen species (ROS) production in the placenta was increased in mice with FGR, and the expression of autophagy-related proteins p-AKT/AKT, p-mTOR/mTOR, and P62 was significantly decreased, while the expression of Beclin-1 and LC3-II was significantly increased in the FGR group. Furthermore, ADMA had a favorable effect in promoting the formation of autophagosomes. Hydroxychloroquine (HCQ) and N-acetylcysteine (NAC) improved ADMA-induced disorders of placental development and alleviated ADMA-induced FGR. This study found that ADMA could cause excessive autophagy of trophoblasts by increasing the level of oxidative stress, ultimately leading to the occurrence of FGR, and HCQ and NAC had therapeutic effects on ADMA-induced FGR.

Quercetin stimulates trophoblast fusion via the mitochondrial function

The fusion of mononuclear trophoblasts into multinucleate syncytiotrophoblasts is the critical event in the process of syncytialization, and its dysregulation can lead to pregnancy complications, notably hypertensive disorders of pregnancy (HDP). Oxidative stress may disrupt trophoblast syncytialization in HDP. Specifically, placentas with HDP exhibit impaired mitochondria, giving rise to the generation of reactive oxygen species (ROS) and subsequent oxidative stress. Quercetin, a bioflavonoid known for its antioxidant and anti-aging properties, has the potential to mitigate oxidative stress during trophoblast syncytialization. However, the precise mechanism underlying the action of quercetin in these processes remains to be elucidated. To explore the impact of quercetin on syncytialization, mitochondrial function, and ROS generation, cyclic AMP-stimulated BeWo cells were treated with quercetin. The expression of markers associated with cell fusion, mitochondrial function, and oxidative stress was determined using qPCR and western blotting. Additionally, morphological syncytialization and mitophagy (mitochondrial degradation) were assessed by immunofluorescence analysis. Our results revealed that quercetin increased the expression of syncytialization markers and promoted cell fusion. Furthermore, this compound also upregulated markers associated with mitophagy and mitochondrial fusion, which are corroborated by visual evidence of mitophagy through the fluorescence microscope. Cell fusion naturally stimulated ROS generation, which was attenuated by quercetin. Quercetin downregulated the expression of NRF2 and HO-1 during syncytialization, while increasing the expression of sirtuin1/3/6, which are known to play essential roles in antioxidant responses. In conclusion, quercetin effectively regulates mitochondrial function through its antioxidant properties and the suppression of ROS generation, ultimately promoting trophoblast fusion, suggesting that the flavonoid has the potential to ameliorate pregnancy-related disorder stemming from placental dysplasia.

Single-cell RNA sequencing reveals association of aberrant placental trophoblasts and FN1 reduction in late-onset fetal growth restriction

IntroductionFetal growth restriction (FGR) can lead to fetal mental development abnormalities, malformations, and even intrauterine death. Defects in the trophoblasts at the maternal-fetal interface may contribute to FGR. However, the impact of trophoblasts on FGR is still not well understood. Therefore, the objective of this study is to characterize the heterogeneity of placental cells at the single-cell level and investigate the role of trophoblast subtypes in the pathogenesis of FGR at the cellular and molecular levels. MethodsSingle-cell RNA sequencing was performed on the maternal side of placentas from two normal pregnant women and two pregnant women with FGR. Lentivirus transfection was used to establish a FN1 knockout model in trophoblast HTR-8-Svneo cells. The effect of FN1 knockout on cell migration and invasion of HTR-8-Svneo cells was assessed through wound healing and transwell assays. ResultsNine cell types were annotated in 39,161 cells derived from single-cell RNA sequencing. The FGR group exhibited a decrease in the percentage of trophoblasts, especially in subtype of extravillous trophoblasts (EVTs). The expression of FN1 was reduced in trophoblasts and EVTs. Furthermore, the protein expression levels of FN1 in the placentas of FGR patients were significantly lower than those of normal pregnant women. The cell migration and invasion ability of HTR-8-Svneo cells were inhibited after the knockdown of FN1. DiscussionThe dysregulation of the trophoblast subtype-EVTs is involved in placental dysplasia related to FGR. The association between aberrant placental trophoblasts and reduced FN1 expression may contribute to insufficient remodeling of spiral arteries and the formation of FGR.

Dysfunction of ZNF554 promotes ROS-induced apoptosis and autophagy in Fetal Growth Restriction via the p62-Keap1-Nrf2 pathway

Fetal growth restriction (FGR) is one of the most common complications of an abnormal pregnancy. Placental dysplasia has been established as a significant contributing factor to FGR. Zinc finger protein 554 (ZNF554) is a member of the Krüppel-associated box domain zinc finger protein subfamily, primarily expressed in the placenta and essential for maintaining normal pregnancy outcomes. However, its precise role in FGR remains uncertain. In this study, we confirmed that ZNF554 was low expressed in the placenta of the FGR pregnancy. To further elucidate the impact of ZNF554 on trophoblasts, we conducted experiments using siRNA and overexpression plasmids on HTR8/SVneo and JEG3 cells. Our findings revealed that silencing ZNF554 increased apoptosis and inhibited migration and invasion, while overexpression reduced apoptosis and promoted migration and invasion. Notably, ZNF554 knockdown decreased cellular antioxidant capacity and elevated the production of reactive oxygen species (ROS). Conversely, ZNF554 activated the nuclear factor E2-related factor 2 (NRF2) signaling pathway, exerting its antioxidant effects. Additionally, ZNF554 knockdown promoted cellular autophagy by suppressing P62 and enhancing LC3-II/LC3-I expression. Importantly, the antioxidant N-acetylcysteine (NAC) partially mitigated the impact of ZNF554 knockdown on mitochondrial ROS in trophoblast cells and subsequent effects on cellular autophagy and apoptosis. In conclusion, our results suggest that ZNF554 plays a pivotal role in modulating trophoblast cell invasion and may serve as a prognostic marker and potential therapeutic target for FGR.

Calcium/calmodulin dependent protein kinase IV in trophoblast cells under insulin resistance: functional and metabolomic analyses

BackgroundInsulin resistance (IR) is an important determinant of glucose metabolic disturbance and placental dysplasia in gestational diabetes mellitus (GDM). Calcium/calmodulin dependent protein kinase IV (CAMK4) improves insulin IR induced by a high-fat diet (HFD). The current study sought to elucidate the role and potential mechanism of CAMK4 in GDM.MethodsA GDM model was established in female C57BL/6J mice via HFD feeding for one week before mating and throughout gestation. The IR was elicited by 10–6 M insulin treatment for 48 h in HTR-8/SVneo cells and mouse primary trophoblast cells. The function of CAMK4 was investigated by transfection of overexpression plasmid in HTR-8/SVneo cells and infection of lentivirus loaded with CAMK4 encoding sequence in primary trophoblast cells. Real-time PCR, western blot, cell counting kit-8, transwell, wound healing, dual-luciferase reporter assay, and liquid chromatography/mass spectrometry-based untargeted metabolomics were performed to confirm the effects of CAMK4 on trophoblast cells.ResultsDecreased CAMK4 expression was found in the placenta of GDM mice. CAMK4 overexpression ameliorated IR-induced viability impairment, migratory and invasive capacity inhibition, autophagy blocking, insulin signaling inactivation and glucose uptake disorder in trophoblast cells. CAMK4 also transcriptionally activated orphan nuclear receptor NUR77, and the effects of CAMK4 were abrogated by silencing of NUR77. Metabolomics analysis revealed that CAMK4 overexpression caused alterations of amino acid, lipid and carbohydrate metabolism, which were important in GDM.ConclusionOur results indicated that CAMK4/NUR77 axis may provide novel potential targets in GDM treatment.

Developmental toxicity of perfluorohexane sulfonate at human relevant dose during pregnancy via disruption in placental lipid homeostasis

Perfluorohexyl sulfonate (PFHxS) is the third most abundant per- and polyfluoroalkyl substances and its developmental toxicity remains very poorly understood. Here, pregnant mice exposed to PFHxS at human relevant dose showed increased fetal death incidence in the high-dose PFHxS-H group (P < 0.01). Body distribution analyses suggested that PFHxS crossed the placental barrier reaching the fetus in a dose-dependent manner. Histopathological data demonstrated impairment in the placenta with reduced blood sinus volume, placental labyrinth area as well as thickness of labyrinthine layer. Further lipidomic and transcriptomic data together showed that PFHxS exposure caused significant disruption in placental lipid homeostasis, including total lipid accumulation in the placenta, and dysregulation in phospholipid and glycerol lipid metabolism. Gene expression analyses uncovered elevation in key placental fatty acid transporters including fabp2, whereas protein expression showed transporter specific disruptions following exposure. Together, gestational exposure to human relevant level of PFHxS may increase the incidence of fetal deaths and caused placental dysplasia via disruption in lipid metabolism homeostasis. These findings raise the concern regarding the highly prevalent and persistent chemical towards early sensitive developing stages and provide basis for further understanding of its effects on lipid metabolism and underlying mechanisms.

Effects of Xenobiotic Compounds on Preeclampsia and Potential Mechanisms.

Preeclampsia (PE) refers to a disease with new hypertension and albuminuria or other end-organ damage after 20 weeks of pregnancy. As a major complication of pregnancy, PE can increase the morbidity and mortality of pregnant women and fetuses and cause serious social burden. Recently, it has been found that exposure to xenobiotic compounds, especially endocrine disruptors in the environment, may contribute to the development of PE. However, the underlying mechanism is still unclear. It is generally believed that PE is related to placental dysplasia, spiral artery remodelling failure, oxidative stress, etc. Therefore, in order to better prevent the occurrence of PE and reduce the damage and impact on mother and fetus, this paper reviews the role and potential mechanism of PE induced by exogenous chemicals and provides an outlook on the environmental etiology of PE.

Tim-3 Coordinates Macrophage-Trophoblast Crosstalk via Angiogenic Growth Factors to Promote Pregnancy Maintenance.

T-cell immunoglobulin mucin-3 (Tim-3) is an important checkpoint that induces maternal-fetal tolerance in pregnancy. Macrophages (Mφs) play essential roles in maintaining maternal-fetal tolerance, remodeling spiral arteries, and regulating trophoblast biological behaviors. In the present study, the formation of the labyrinth zone showed striking defects in pregnant mice treated with Tim-3 neutralizing antibodies. The adoptive transfer of Tim-3+Mφs, rather than Tim-3-Mφs, reversed the murine placental dysplasia resulting from Mφ depletion. With the higher production of angiogenic growth factors (AGFs, including PDGF-AA, TGF-α, and VEGF), Tim-3+dMφs were more beneficial in promoting the invasion and tube formation ability of trophoblasts. The blockade of AGFs in Tim-3+Mφs led to the narrowing of the labyrinthine layer of the placenta, compromising maternal-fetal tolerance, and increasing the risk of fetal loss. Meanwhile, the AGFs-treated Tim-3-Mφs could resolve the placental dysplasia and fetal loss resulting from Mφ depletion. These findings emphasized the vital roles of Tim-3 in coordinating Mφs-extravillous trophoblasts interaction via AGFs to promote pregnancy maintenance and in extending the role of checkpoint signaling in placental development. The results obtained in our study also firmly demonstrated that careful consideration of reproductive safety should be taken when selecting immune checkpoint and AGF blockade therapies in real-world clinical care.

Placenta-Targeted Nanoparticles Loaded with PFKFB3 Overexpression Plasmids Enhance Angiogenesis and Placental Function.

Placental angiogenesis disorder and placental dysplasia are important causes of many pregnancy complications. Due to safety and economic benefits, effective treatment strategies are currently limited. PFKFB3 is a key regulator of glycolysis that controls angiogenesis through a metabolic pathway independent of genetic signals. In this study, we constructed the nanodrug T-NPPFKFB3 and explored its feasibility to promote angiogenesis and enhance placental function. First, liposomes containing PFKFB3 overexpression plasmids modified by the placental homing peptide CGKRK were synthesized by the thin film method. In vivo experiments revealed that T-NPPFKFB3 injected intravenously specifically accumulated in the mouse placenta and therein upregulated the expression of PFKFB3 without affecting its expression in other important organs. In addition, T-NPPFKFB3 promoted placental angiogenesis and increased the fetal and placental weights of the mice. Finally, we evaluated the safety of T-NPPFKFB3. The expression levels of ALS/AST/BUN in the sera of pregnant mice were not significantly different from those in the sera of control group mice. However, T-NPPFKFB3 did not cause obvious fetal abnormalities or alter the average litter size. In conclusion, T-NPPFKFB3 can specifically target the placenta, promote angiogenesis, and enhance placental function without obvious side effects. Therefore, it has potential as a new strategy for the treatment of pregnancy complications.

Placental Therapeutic Targets and Nanodelivery Systems.

Pregnancy complications affect millions of women each year. Some of these diseases have high morbidity and mortality such as preeclampsia. At present, there is no safe and effective treatment for pregnancy complications, so it is still a difficult clinical problem. As many pregnancy complications are closely related to placental dysplasia, placenta-specific therapy, as an important method, is expected to be a safe, effective, and specific therapeutic strategy. This review explains in detail the placenta physiological structure, characteristics, and action mechanism of some biomolecules and signaling pathways that play roles in normal development and disorders of the development of the placenta, and how to use these biomolecules as therapeutic targets when the placenta disorder causes disease, combining the latest progress in the field of nanodelivery systems, so as to lay a foundation for the development of placenta-specific therapy of pregnancy complications.

Exploration of fetal growth restriction induced by vitamin D deficiency in rats via Hippo-YAP signaling pathway

IntroductionMaternal vitamin D deficiency (VDD) is associated with intrauterine growth restriction (IUGR), but the exact mechanism remains unclear. Here we explored the mechanism through which VDD induced IUGR. MethodsFemale SD rats were fed a control normal diet (VD > 800 IU/Kg) or VDD diet (VD: 0 IU/Kg) for 8 weeks. Then, females were mated with 12-week-old male SD rats, and fetal and placental tissue were collected on the gestational day 13 (GD13) or 18 (GD18) to analyze the effects of VDD on pregnancy outcome and embryonic development. In vitro, the VDR gene of HTR-8/SVneo cells was knocked down to establish VDD model. Then, HTR-8/SVneo cells were treated with the MST1/2 inhibitor XMU-MP-1 or 0.1 μM/L calcitriol for 24 h (h). The mechanism of Hippo-YAP signaling pathway in VDD-induced placental dysplasia was further investigated by western blot, invasion assay, wound healing assay and Hoechst/PI staining. ResultsThe IUGR of the pregnant rats in the VDD group was significant, the placental structure and function were damaged, and there was an obvious inflammatory response, accompanied by a significant increase in the level of the transcription co-activator YAP phosphorylation. In vitro, VDD significantly inhibited the migratory and invasive abilities of HTR-8/SVneo cells, accompanied by decreased EMT capacity and increased apoptosis. When intervening with XMU-MP-1 in advance, we found that the effects of VDD were neutralized by Hippo-YAP signaling blocker. DiscussionMaternal VDD causes placental dysplasia and IUGR, and these abnormal changes may be associated with the activation of Hippo-YAP signaling pathway.

Downregulation of CDC42 inhibits the proliferation and stemness of human trophoblast stem cell via EZRIN/YAP inactivation.

Placental dysplasia increases the risk of recurrent spontaneous abortion (RSA). However, the underlying mechanism regulating placental development remains unclear. In this study, we showed that the expression of CDC42 was decreased in the villous tissue of RSA samples compared to healthy controls. Further examination demonstrated that CDC42 deficiency led to the differentiation of human trophoblast stem cells (hTSCs) and inhibited their proliferation. Genetic manipulation of YAP and EZRIN in hTSCs revealed that CDC42 regulates the stemness and proliferation of hTSCs; this is dependent on EZRIN, which translocates YAP into the nucleus. Moreover, the expression pattern of EZRIN, YAP, and Ki67 was also abnormal in the villous tissue of RSA samples, consistent with in vitro experiments. In summary, these findings suggest that the CDC42/EZRIN/YAP pathway plays an important role in placental development.

79 A partial hydatidiform mole case with rare karyotype

Introduction: A hydatiform mole is a gestational trophoblastic disease, which originates from the placenta and can metastasize. In complete moles, the karyotype is 46,XX 90% of the time and 46,XY 10% of the time. On the other hand, in partial moles, the karyotype is 90% of the time triploid and either 69,XXX or 69,XXY. In developed countries, the incidence of complete moles is approximately 1–3 per 1000 pregnancies and those of the partial moles about 3 per 1000 pregnancies. Methods: Our case was referred us at 17. week of pregnancy because of her high AFP value at routine screening. It was also hyperechogenic fetal bowel, pericardial effusion and placental thickness observed in ultrasonographic examination. At the beginning we put forward molar pregnancy or placental dysplasia in this case and made genetic analysis with amniocentesis. We also investigated TORCH screening but found no specific finding. During these investigation maternal hypertension and proteinuria, growth restriction at fetus was occurred. With these findings we recommended the family to termination and they accepted. Results: After termination we sent fetal material to pathological examination. The result from pathology indicated that the fetal material included partial molar pregnancy with 46 chromosomes. That means it was a rare partial molar pregnancy case with 46 chromosomes. Conclusions: Patial mole is seen with a fetus but complete mole is characterised with molar plasental hypertrphy without fetus. In a partial mole, there typically is the finding of a fetus which may be viable, the presence of amniotic fluid, and the placenta appears to have enlarged, cystic spaces. For partial moles, fertilization takes place between the oocyte and 2 sperm. The zygote is thus triploid. In rare cases the partial hydatidiform mole have also been reported with other karyotypes.

Vaginal Exposure to Candida albicans During Early Gestation Results in Adverse Pregnancy Outcomes via Inhibiting Placental Development.

Vulvovaginal candidiasis (VVC) is considered the second most common cause of vaginitis after bacterial vaginosis and the most common lower genital tract infection during pregnancy. Candida albicans (C. albicans), an opportunistic pathogen, is the major species causing VVC. Recently, increasing researches have shown that lower reproductive tract infection during pregnancy can lead to various adverse pregnancy outcomes. However, the underlying mechanisms are not fully understood. Hence, we successfully established a mouse model of vaginal C. albicans infection and characterized the adverse pregnancy outcomes. C. albicans infection strikingly increased abortion rate and decreased litter size. Further analysis of placental development demonstrated that placental structure was abnormal, including that the area of spongiotrophoblast (Spo) and labyrinth (Lab) was reduced, and the formation of placental vessel was decreased in Lab zone. Accordingly, the expression of marker genes during placental development was downregulated. Collectively, the above findings revealed that vaginal C. albicans infection during pregnancy can inhibit placental development and ultimately lead to adverse pregnancy outcomes. This study enhances our comprehension of the effect of VVC on pregnancy, and placental dysplasia as a feasible orientation to explore VVC during pregnancy.

Mechanism of neutrophil extracellular traps generation and their role in trophoblasts apoptosis in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a metabolic syndrome occurring in pregnant women and increases the risk of placental dysplasia. Neutrophil extracellular traps (NETs) may play a critical role in placental dysplasia. NETosis (neutrophil cell death by NET release) depends on NADPH/ROS pathway. In view of the adiponectin which is widely believed to be reduced in GDM patients suppresses NADPH oxidase and ROS generation of neutrophil. We speculate that increased NET release is associated with hypoadiponectinemia. Trophoblast apoptosis is significantly increased in GDM patients, but it is not clear whether NETs promotes cell apoptosis. This study aims to reveal the mechanism of Neutrophil Extracellular Traps generation and their role in trophoblast apoptosis in Gestational Diabetes Mellitus. We investigated the generation of NETs by cell-free DNA (cf-DNA) quantification, live-cell imaging, and reactive oxygen species (ROS) measurement. ERK1/2 and p38 MAPK signalling pathway proteins were detected by western blotting. The Cell Counting Kit-8 (CCK-8) assay, flow cytometry, and western blotting were performed to explore the effects of NETs on trophoblast apoptosis. We found that adiponectin inhibited NET release by suppressing ROS production, and p38 MAPK and ERK1/2 proteins were involved in the process. Further, NETs promoted trophoblast apoptosis by activating the ROS-dependent mitochondrial pathway, which is mediated by ERK1/2 signalling. The current study demonstrated that hypoadiponectinemia is the cause of NETs formation and NETs promoting trophoblast apoptosis.

Circulating Exosomal miR-221 from Maternal Obesity Inhibits Angiogenesis via Targeting Angptl2.

Maternal obesity disrupts both placental angiogenesis and fetus development. However, the links between adipocytes and endothelial cells in maternal obesity are not fully understood. The aim of this study was to characterize exosome-enriched miRNA from obese sow’s adipose tissue and evaluate the effect on angiogenesis of endothelial cells. Plasma exosomes were isolated and analyzed by nanoparticle tracking analysis (NTA), electron morphological analysis, and protein marker expression. The number of exosomes was increased as the gestation of the sows progressed. In addition, we found that exosomes derived from obese sows inhibited endothelial cell migration and angiogenesis. miRNA detection showed that miR-221, one of the miRNAs, was significantly enriched in exosomes from obese sows. Further study demonstrated that exosomal miR-221 inhibited the proliferation and angiogenesis of endothelial cells through repressing the expression of Angptl2 by targeting its 3′ untranslated region. In summary, miR-221 was a key component of the adipocyte-secreted exosomal vesicles that mediate angiogenesis. Our study may be a novel mechanism showing the secretion of “harmful” exosomes from obesity adipose tissues causes placental dysplasia during gestation.

Expression of hypoxia-inducible factor-1 in mice infected with Toxoplasma gondii during pregnancy

To investigate the expression and possible role of hypoxia-inducible factor-1 (HIF-1) at the maternal-fetal interface following Toxoplasma gondii infection during early pregnancy. Twenty pregnant C57BL/6 mice, each weighing 16 to 20 g, were randomly divided into 4 groups, including the 12-d control group, 12-d infection group, 18-d control group and 18-d infection group. Mice in the 12-d and 18-d infection groups were injected intraperitoneally with 150 tachyzoites of the T. gondii PRU strain on day 6 of pregnancy, while mice in the 12-d control and 18-d control groups were injected with the same volume of phosphate buffered saline (PBS). Mice in the control and infection groups were sacrificed on days 12 and 18 of pregnancy, and the placental and uterine specimens of the pregnant mice in each group were sampled for pathological examinations. The mRNA expression of HIF-1α, HIF-1β and vascular endothelial growth factor (VEGF) was quantified using quantitative fluorescent real-time PCR (qPCR) assay in the placental and uterine specimens, and the correlation between HIF-1α and VEGF mRNA expression was examined. In addition, and the HIF-1α expression was detected using immunohistochemical staining in the placental and uterine specimens of pregnant mice. Compared with the 12-d and 18-d control groups, adverse pregnant outcomes were observed in mice in 12-d and 18-d infection groups, such as teratism and placental dysplasia. HE staining showed swelling and blood stasis of cells, sinusoid reduction and inflammatory cell infiltration in the labyrinth area of the placenta specimens of mice in 12-d and 18-d infection groups relative to 12-d and 18-d control groups, and columnar epithelial cell injury and inflammatory cell infiltration were seen in the mouse uterine specimens in both infection groups. qPCR assay detected significantly higher HIF-1α (F = 132.6, P < 0.05) and HIF-1β mRNA expression (F = 286.9, P < 0.05) in the placental specimens and lower HIF-1α (F = 111.5, P < 0.05) and HIF-1β mRNA expression (F = 55.2, P < 0.05) in the uterine specimens in the 12-d infection group than in the 12-day control group, and significantly lower HIF-1α and HIF-1β mRNA expression was detected in the placental and uterine specimens in the 18-d infection group than in the 18-day control group (F = 215.8, 418.9, 156.8 and 200.1; all P values < 0.05). Significantly lower VEGF-A (F = 426.2, P < 0.05), VEGF-B (F = 104.6, P < 0.05) and VEGF-C mRNA expression (F = 566.9, P < 0.05) in the placental specimens and higher VEGF-A (F = 426.2, P < 0.05), VEGF-B (F = 104.6, P < 0.05) and VEGF-C mRNA expression (F = 566.9, P < 0.05) in the uterine specimens were detected in the 12-d infection group than in the 12-d control group, and higher VEGF-A, VEGF-B and VEGF-C mRNA expression was found in the placental and uterine specimens in the 18-d infection group than in the 18-d control group (F = 521.9, 100.6, 275.9, 224.6, 108.2 and 333.4; all P values < 0.05). Immunohistochemical staining showed strongly and mildly positive HIF-1α expression in the mouse placental labyrinth area in the 12-d and 18-d infection groups relative to 12-d and 18-d control groups, while no HIF-1α expression was detected in mouse uterine specimens. HIF-1α expression appears a tendency towards a rise in the second trimester and a reduction in the third trimester in mice following T. gondii infection during early pregnancy, which is contrary to the changing tendency of VEGF-A, VEGF-B, and VEGF-C expression. It is hypothesized that HIF-1α inhibits placental angiogenesis in mice during pregnancy through suppressing VEGF expression, resulting in adverse pregnant outcomes.

PD-1/PD-L1 expression and its interaction with interferon-γ in Toxoplasma gondii-infected mice at middle and late pregnancy

To explore the dynamic expression of programmed cell death-1 (PD-1) and its ligand PD-L1 at the maternal-fetal interface of mice post-infection with Toxoplasma gondii at early pregnancy and examine its interaction with interferon-γ (IFN-γ). A total of 20 mice at day 0 of pregnancy were randomly assigned into 4 groups, including the 12-day pregnancy control group (12 dpn group), 12-day pregnancy and infection group (12 dpi group), 18-day pregnancy control group (18 dpn group) and 18-day pregnancy and infection group (18 dpi group), respectively. On the 6th day of the pregnancy, mice in the 12 dpi and 18 dpi groups were injected intraperitoneally with 150 tachyzoites of the T. gondii PRU strain, while mice in the 12 dpn and 18 dpn groups were injected with the same volume of PBS. All mice in the four groups were sacrificed on 12th and 18th day of the pregnancy, and the number of placenta and fetus was counted and the weight of placenta and fetus was measured. Then, the placental and uterine tissues of the pregnant mice in each group were sampled for pathological examinations. The mRNA expression of PD-1, PD-L1, T. gondii surface antigen SAG-1 and IFN-γ genes was quantified using a quantitative real-time PCR (qPCR) assay, and the correlation between PD-1 and IFN-γ expression was examined. In addition, the 12 dpn group, 12 dpi group, 18 dpn group, 18 dpi group, PBS negative control of the 12 pdi group and PBS negative control of the 18 dpi group were assigned, and the PD-1 expression was determined in the uterine and placenta tissues of the pregnant mice. Adverse pregnant outcomes were seen in mice in the 12 dpi and 18 dpi groups, including placental dysplasia and fetal maldevelopment, and the placental weights and fetal body weights were significantly lower in mice in the 12 dpi and 18 dpi groups than those in the 12 dpn and 18 dpn groups (t = 5.52, 11.44, 12.63 and 11.67, all P < 0.01). The histopathological examinations showed that the decidua and junctional regions of the placental tissues were loosely connected in the 12 dpi and 18 dpi groups, and a large number of inflammatory cells infiltration and congestion were seen in the placental and uterine tissues. qPCR assay detected significant differences in PD-1, PD-L1, IFN-γ and SAG-1 expression in the placental and uterine tissues among the 12 dpn, 12 dpi, 18 dpn and 18 dpi groups (F = 22.48, 51.23, 9.61, 47.49, 16.08, 21.52, 28.66 and 238.90, all P < 0.05), and the PD-1, PD - L1, IFN - γ and SAG - 1 expression was all significantly higher in the placental and uterine tissues of mice in the 12 dpi group than in the 12 dpn group (all P values < 0.05). The PD-1 and PD-L1 expression was significantly lower in the placental tissues of mice in the 18 dpi group than in the 18 dpn group (all P values < 0.05), and the IFN-γ and SAG-1 expression was significantly higher in the placental and uterine tissues of mice in the 18 dpi group than in the 18 dpn group (all P values < 0.05), while the PD-1 and PD-L1 expression was significantly lower in the placental and uterine tissues of mice in the 18 dpi group than in the 12 dpi group (all P values < 0.05). Immunohistochemical staining showed PD-1 expression in the inflammatory cells of the placental tissues of mice in the 12 dpi group, and no apparent PD-1 expression in the 18 dpi group, while strongly positive PD-1 expression was found in the uterine epithelium of mice in the 12 dpi group, and mildly strong expression was in the 18 dpi group. In addition, the IFN-γ mRNA expression was positively correlated with the PD-1 mRNA expression in placental (rs = 0.99, P < 0.01) and uterine tissues of mice in the 12 dpi group (rs = 0.97, P < 0.01) and in placental (rs = 0.82, P < 0.01) and uterine tissues of mice in the 18 dpi group (rs = 0.81, P < 0.01). Following T. gondii infection at early pregnancy, the PD-1 and PD-L1 expression shows a remarkable rise at middle pregnancy and a reduction at late pregnancy in placental and uterine tissues of mice, which appears the same tendency with IFN-γ expression during the same time period, and PD-1 expression positively correlates with IFN-γ expression. The dynamic expression of PD-1 and PD-L1 on the maternal-fetal interface of mice may be mutually mediated by IFN-γ induced by T. gondii infection.