Neutrophil Depletion Exacerbates Pregnancy Complications, Including Placental Damage, Induced by Silica Nanoparticles in Mice

Maternal exposure to ZIF-8 derails placental function by inducing trophoblast pyroptosis through neutrophils activation in mice

Adverse environmental factors during maternal gestation pose a threat to pregnancy. Environmental factors, particularly nanoparticles, can impact pregnancy by causing damage to the placenta. Compared to early gestation, foetuses in late gestation are more robustly developed and at lower risk of adverse effects from environmental factors. Delivery systems for targeted therapy during pregnancy is predominantly focused on their application in late gestation. Zeolitic imidazolate framework-8 (ZIF-8) holds great potential for targeted drug therapy. To evaluate the value of ZIF-8 in targeted treatment of disorders associated with late gestation, it is crucial to investigate the biological effects of ZIF-8 exposure during late gestation. Here, a mouse model exposed to ZIF-8 particles at different doses (5, 10, and 15 mg/kg) during late gestation was constructed. We found that ZIF-8 particles were deposited in the uterus of pregnant mice. ZIF-8 could trigger placental neutrophil aggregation and induce inflammation, which led to trophoblast pyroptosis and impair placental function, adversely affecting the foetus. Neutrophil depletion alleviated placental and foetal damage induced by ZIF-8. This study provides a novel mechanistic view of the reproductive toxicity induced by ZIF-8 and may offer clues to reduce the latent harm of adverse environmental factors to pregnancy.

Decidual derived exosomal miR-99a-5p targets Ppp2r5a to inhibit trophoblast invasion in response to CeO2NPs exposure

BACKGROUND

The biological effects of cerium dioxide nanoparticles (CeO₂NPs), a novel material in the biomedical field, have attracted widespread attention. Our previous study confirmed that exposure to CeO₂NPs during pregnancy led to abnormal trophoblast invasion during early placental development, thereby impairing placental development. The potential mechanisms may be related to low-quality decidualization triggered by CeO₂NPs exposure, such as an imbalance in trophoblast invasion regulators secreted by decidual cells. However, the intermediate link mediating the "dialogue" between decidual cells and trophoblasts during this process remains unclear. As an important connection between cells, exosomes participate in the "dialogue" between endometrial cells and trophoblasts. Exosomes transfer bioactive microRNA into target cells, which can target and regulate the level of mRNA in target cells.

RESULTS

Here, we constructed a mice primary uterine stromal cell-induced decidualization model in vitro, and detected the effect of CeO₂NPs exposure on the expression of decidual-derived exosomal miRNAs by high-throughput sequencing. Bioinformatics analysis and dual-luciferase reporter assays were performed to identify target genes of the screened key miRNAs in regulating trophoblast invasion. Finally, the role of the screened miRNAs and their target genes in regulating trophoblast (HTR-8/SVneo cells) invasion was confirmed. The results showed that CeO₂NPs exposure inhibited trophoblast invasion by promoting miR-99a-5p expression in decidual-derived exosomes, and Ppp2r5a is a potential target gene for miR-99a-5p to inhibit trophoblast invasion.

CONCLUSIONS

This study revealed the molecular mechanism by which CeO₂NPs exposure inhibits trophoblast invasion from the perspective of decidual derived exosomal miRNAs. These results will provide an experimental basis for screening potential therapeutic targets for the negative biological effects of CeO₂NPs exposure and new ideas for studying the mechanism of damage to trophoblast cells at the decidual-foetal interface by harmful environmental or occupational factors.

Gestationally dependent immune organization at the maternal-fetal interface

The immune system and placenta have a dynamic relationship across gestation to accommodate fetal growth and development. High-resolution characterization of this maternal-fetal interface is necessary to better understand the immunology of pregnancy and its complications. We developed a single-cell framework to simultaneously immuno-phenotype circulating, endovascular, and tissue-resident cells at the maternal-fetal interface throughout gestation, discriminating maternal and fetal contributions. Our data reveal distinct immune profiles across the endovascular and tissue compartments with tractable dynamics throughout gestation that respond to a systemic immune challenge in a gestationally dependent manner. We uncover a significant role for the innate immune system where phagocytes and neutrophils drive temporal organization of the placenta through remarkably diverse populations, including PD-L1⁺ subsets having compartmental and early gestational bias. Our approach and accompanying datasets provide a resource for additional investigations into gestational immunology and evoke a more significant role for the innate immune system in establishing the microenvironment of early pregnancy.

Silver nanoparticles suppress forskolin-induced syncytialization in BeWo cells

Opportunities for the exposure of pregnant women to engineered nanoparticles have been increasing with the expanding use of these materials. Therefore, there are concerns that nanoparticles could have adverse effects on the establishment and maintenance of pregnancy. The effects of nanoparticles on the mother and fetus have been evaluated from this perspective, but there is still little knowledge about the effects on placentation and function acquisition, which are essential for the successful establishment and maintenance of pregnancy. Formation of the syncytiotrophoblast is indispensable for the acquisition of placental function, and impairment of syncytialization inevitably affects pregnancy outcomes. Here, we assessed the effect of nanoparticles on placental formation by using forskolin-treated BeWo cells, a typical in vitro model of trophoblast syncytialization. Immunofluorescence staining analysis revealed that silver nanoparticles with a diameter of 10 nm (nAg10) (at 0.156 µg/mL) significantly decreased the proportion of syncytialized BeWo cells, but gold nanoparticles with a diameter of 10 nm did not. Consistently, only nAg10 (at 0.156 µg/mL) significantly suppressed forskolin-induced elevation of CGB and SDC1 mRNA expression levels and human chorionic gonadotropin β production in a dose-dependent manner; these molecules are all markers of syncytialization. Besides, nAg10 significantly decreased the expression of ERVFRD-1, which encodes proteins associated with cell fusion. Moreover, nAg10 tended to suppress the expression of sFlt-1 e15a, a placental angiogenesis marker. Collectively, our data suggest that nAg10 could suppress formation of the syncytiotrophoblast and that induce placental dysfunction and the following poor pregnancy outcomes.

Neutrophil depletion in the pre-implantation phase impairs pregnancy index, placenta and fetus development

Maternal neutrophils cells are players in gestational tolerance and fetus delivery. Nonetheless, their actions in each phase of the pregnancy are unknown. We here investigated the role of maternal neutrophil depletion before the blastocyst implantation phase and outcomes in the pregnancy index, placenta, and fetus development. Neutrophils were pharmacologically depleted by i.p. injection of anti-Gr1 (anti-neutrophils; 200 µg) 24 hours after plug visualization in allogeneic-mated C57BL/6/BALB/c mice. Depletion of peripheral neutrophils lasted until 48 hours after anti-Gr1 injection (gestational day 1.5-3.5). On gestational day 5.5, neutrophil depletion impaired the blastocyst implantation, as 50% of pregnant mice presented reduced implantation sites. On gestational day 18.5, neutrophil depletion reduced the pregnancy rate and index, altered the placenta disposition in the uterine horns, and modified the structure of the placenta, detected by reduced junctional zone, associated with decreased numbers of giant trophoblast cells, spongiotrophoblast. Reduced number of placenta cells labeled for vascular endothelial growth factor (VEGF), platelet-endothelial cell adhesion molecule (PECAM-1), and intercellular cell adhesion molecule (ICAM-1), important markers of angiogenesis and adhesiveness, were detected in neutrophil depleted mice. Furthermore, neutrophil depletion promoted a higher frequency of monocytes, natural killers, and T regulatory cells, and lower frequency of cytotoxic T cells in the blood, and abnormal development of offspring. Associated data obtained herein highlight the pivotal role of neutrophils actions in the early stages of pregnancy, and address further investigations on the imbricating signaling evoked by neutrophils in the trophoblastic interaction with uterine epithelium.

Health Effects and Safety Assurance of Nanoparticles in Vulnerable Generations

Nanoparticles have a variety of useful functions. They have already been put to practical use in products in many industrial arenas, such as the cosmetics and food fields. Therefore, we cannot avoid the unintentional nanoparticle exposure of vulnerable people such as pregnant women and infants, and the importance of evaluating the safety of such vulnerable generations, who are highly sensitive to chemical substances, has been pointed out worldwide. However, it is still difficult to determine the hazards posed by nanoparticle exposure in everyday life. From this perspective, to analyze the risk from nanoparticles to vulnerable generations, nano-safety science research has been conducted through the collection of toxicity information on nanoparticles based on their physicochemical properties and kinetics via the association analysis of physicochemical properties, kinetics, and toxicity. The results of this nano-safety science research have been used in nano-safety design research to develop safer forms of nanoparticles. The findings of these studies will not only provide insights that will help us to formulate new policies for the risk management of nanoparticles; they will also lead directly to the development of sustainable nanotechnology (nanotechnology that can be safely, usefully, and sustainably used). These developments will contribute not only to the development of the nano-industry and the promotion of its social acceptance, but also to future developments in the field of health science.

Exposure to two-dimensional ultrathin Ti3C2 (MXene) nanosheets during early pregnancy impairs neurodevelopment of offspring in mice

Background

Two-dimensional ultrathin Ti₃C₂ (MXene) nanosheets have been extensively explored for various biomedical applications. However, safety issues and the effects of Ti₃C₂ on human health remain poorly understood.

Results

To explore the influence on foetal or offspring after exposure to Ti₃C₂ nanosheets, we established a mouse model exposed to different doses of Ti₃C₂ nanosheets during early pregnancy in this study. We found that Ti₃C₂ nanosheets had negligible effect on the reproductive ability of maternal mice, including average pregnancy days, number of new-borns, and neonatal weight, etc. Unexpectedly, abnormal neurobehavior and pathological changes in the cerebral hippocampus and cortex in adult offspring were observed following Ti₃C₂ nanosheet treatment. In further studies, it was found that Ti₃C₂ exposure led to developmental and functional defects in the placenta, including reduced area of labyrinth, disordered secretion of placental hormones, and metabolic function derailment. The long-chain unsaturated fatty acids were significantly higher in the placenta after Ti₃C₂ exposure, especially docosahexaenoic acid (DHA) and linoleic acid. The metabolic pathway analysis showed that biosynthesis of unsaturated fatty acids was upregulated while linoleic acid metabolism was downregulated.

Conclusions

These developmental and functional defects, particularly metabolic function derailment in placenta may be the cause for the neuropathology in the offspring. This is the first report about the effects of Ti₃C₂ nanosheet exposure on pregnancy and offspring. The data provides a better understanding of Ti₃C₂ nanosheets safety. It is suggested that future studies should pay more attention to the long-term effects of nanomaterials exposure, including the health of offspring in adulthood, rather than only focus on short-term effects, such as pregnancy outcomes. Metabolomics could provide clues for finding the prevention targets of the biological negative effect of Ti₃C₂ nanosheets.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01313-z.

Possible impact of neutrophils on immune responses during early pregnancy in ruminants

The interaction between early embryo and maternal immune system for the establishment of pregnancy is the focus of several studies; however, it remains unclear. The maternal immune response needs to keep a balance between avoiding any damage to the conceptus and maintaining its function in combating microbes as well. When conceptus-maternal crosstalk cannot achieve this balance, pregnancy losses might occur. Intercommunication between mother and conceptus is fundamental during early pregnancy to dictate the outcome of pregnancy. In ruminants, the embryo reacts with the maternal system mainly via interferon tau (IFNT) release. IFNT can act locally on the embryo and endometrial cells and systemically in several tissues and cells to regulate their response via the expression of interferon-stimulated genes (ISGs). Also, IFNT can induce the expression of inflammatory-related genes in immune cells. Day 7 embryo induces a shift in the maternal immune response towards anti-inflammatory (Th2) immune responses. During maternal recognition of pregnancy, peripheral mononuclear cells (PBMCs) and polymorphonuclear cells (PMNs) express markers that configure an anti-inflammatory response. However, PMNs response is more sensitive to the effects of IFNT. PMNs are more likely to express interferon-stimulated genes (ISGs), transforming growth factor-beta (TGFB), interleukin 10 (IL10), and arginase-1 (ARG1), configuring one of the most rapid immune responses to early pregnancy. This review focus on the local and peripheral immune responses during early pregnancy in ruminants, mainly the PMNs function in the immune system.

Maternal magnolol supplementation alters placental morphology, promotes placental angiogenesis during mid-gestation and improves offspring growth in a pregnant mouse model

The placenta is the organ that determines the growth of the fetus and the outcome of pregnancy. Magnolol is a multifunctional polyphenol with antioxidant, anti-inflammatory, anticancer and neuroprotective functions. However, there is less knowledge of the effects or complications in the placenta and the mechanism underlying the effect of magnolol when used during pregnancy. The aim of this study was to explore the effects of maternal magnolol supplementation on pregnancy outcomes and placental alterations in a pregnant mouse model. A total of 128 pregnant mice were randomly divided into 4 groups supplemented with 0, 40, 80 and 160 μM magnolol from gestational day 0 (GD0) to delivery. Our results revealed that the number of large-for-gestation-age fetuses on GD13 and the weaning weight of offspring were increased in the magnolol treatment groups. Moreover, maternal magnolol supplementation increased superoxide dismutase (SOD), decreased malondialdehyde (MDA) in maternal serum, and promoted the expression of heme oxygenase-1 (HO-1) in the placenta. Furthermore, magnolol significantly increased the area of the junctional zone and decidua in the placentas and increased the expression of interferon-γ (INF-γ), tumor necrosis factor-α (TNF-α), chemokine (CC Motif) Ligand 3 (CCL3), chemokine (CXC motif) ligand 10 (CXCL10), insulin-like growth factor-1 (IGF-1) and T-box transcription factor 21 (T-bet) in the placenta during GD13 in pregnant mice, while suppressor of cytokine signaling 1 (SOCS1) was reduced. Moreover, the ratio of blood space in the labyrinth area, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) were all increased in the magnolol treatment groups on GD13. Taken together, these results indicate that magnolol can improve the growth of offspring, which might be due to the alteration of placental morphology and the promotion of placental angiogenesis during mid-gestation.

Uterine pyruvate metabolic disorder induced by silica nanoparticles act through the pentose phosphate pathway

Silica nanoparticles (SiNPs) have drawn considerable attention due to their environmental health effects, while enhanced understanding of metabolic disorders has provided insight into related diseases. To investigate the impacts of SiNPs exposure on reproduction and reveal their pathogenic mechanisms, this study was designed and conducted from a metabolic perspective. First, fluorescein isothiocyanate (FITC)-SiNPs were chemically synthesized and applied to track SiNPs in vitro and in vivo. Next, 30 pregnant mice were intratracheally instilled with 1.25 mg of SiNPs/mouse, then sacrificed 24 h post-treatment. We found that SiNPs penetrated the trophoblast membrane, triggering apoptosis and inhibiting cell proliferation, invasion, and tube formation in a dose-dependent manner. Mechanistically, SiNPs dysregulated phosphofructokinase (Pfkl) and fructose-bisphosphatase 2 (Fbp2) and induced glucose depletion and pyruvate accumulation via the pentose phosphate pathway. Besides, the downregulation of caspase-3 suggested a causal relationship between pyruvate accumulation, pentose phosphate pathway activation, and cell apoptosis. Pfkl and Fbp2 was also dysregulated in vivo, and the uterine inflammation aggravated in a time-dependent manner. In conclusion, SiNPs triggered acute cytotoxicity and uterine inflammation by inducing glucose depletion and pyruvate overload in trophoblasts, which were mediated in part by Pfkl and Fbp2 via the pentose phosphate pathway.

A comparative study on various immunological parameters influencing embryo survivability in crossbred dairy cows

Since long embryonic mortality has remained an area of concern affecting the reproduction, production, and profitability of dairy cows. We investigated the possible interaction between interleukins, hormones, and neutrophil associated CD markers during the implantation window in Karan Fries (KF) cows naturally coming to heat. Blood collection was done on days 0 i.e. day of Artificial Insemination (AI), 10, 18, 21, 30 and on day 40 post-AI. Total leucocyte count (TLC) and neutrophil to lymphocyte (N:L) ratio were recorded. Blood neutrophils were isolated and their number, phagocytic activity (PA), myeloperoxidase (MPO) concentration and relative mRNA expression of cell adhesion molecules (CD-11b, CD-31, CD-44, CD-62L) as well as progesterone-inducing-blocking-factor (PIBF) and glucocorticoid receptor alpha (GRα) were examined. Plasma progesterone, cortisol, IL-2, IL-8, IL-6, and IL-10 were also measured. Pregnancy was confirmed by non-return to heat, ultrasonography and per rectal examination along with progesterone assay. Cows were further divided into pregnant (P), early embryonic mortality (EEM) and late embryonic mortality (LEM) groups. Embryonic losses cows showed lower plasma concentration of IL-10 (<100 pg/ml) and a higher concentration of IL-2 (>500 pg/ml). Also, a 4 fold increase in the relative mRNA expression of CD-11b and 2.5 fold changes in CD-44 expression were observed in embryonic mortality. We observed a 1.5 fold increase in the relative mRNA expression of PIBF and a 0.5 fold increase in GRα expression in pregnant cows compared to EEM (on day 21) and LEM (on days 30 and 40) cows. Our results depicted that the hyperimmune status of the dam which could be due to multifactorial events that led to the pregnancy failure. The above basic values may be used for checking the immune status and thus timely management strategies can be taken to prevent embryonic losses.

Endometrial Cancer Immune Escape Mechanisms: Let Us Learn From the Fetal-Maternal Interface

The immune escape mechanisms at the base of tumor progression in endometrial cancer mimic immune tolerance mechanisms occurring at the maternal-fetal interface. The biological and immunological processes behind the maternal-fetal interface are finely tuned in time and space during embryo implantation and subsequent pregnancy stages; conversely, those behind cancer progression are often aberrant. The environment composition at the maternal-fetal interface parallels the pro-tumor microenvironment identified in many cancers, pointing to the possibility for the use of the maternal-fetal interface as a model to depict immune therapeutic targets in cancer. The framework of cancer environment signatures involved in immune adaptations, precisely timed in cancer progression, could reveal a specific "immune clock" in endometrial cancer, which might guide clinicians in patient risk class assessment, diagnostic workup, management, surgical and therapeutic approach, and surveillance strategies. Here, we review studies approaching this hypothesis, focusing on what is known so far about oncofetal similarities in immunity with the idea to individualize personalized immunotherapy targets, through the downregulation of the immune escape stage or the reactivation of the pro-inflammatory processes suppressed by the tumor.

Intrauterine Inflammation Damages Placental Angiogenesis via Wnt5a-Flt1 Activation

Intrauterine inflammation is the main reason for neonatal adverse outcomes and normal placenta perfusion plays an important role in fetal development. However, whether inflammation will affect placental angiogenesis and the underlying mechanism are still poorly understood. To investigate lipopolysaccharide (LPS)-induced intrauterine inflammation on placenta angiogenesis and Wnt5a-Flt1 expression. LPS-induced intrauterine inflammation rat model was established. Preterm rat outcomes were analyzed and angiogenesis of placenta villi was calculated by immunohistochemistry (IHC) of CD34 staining, and placenta Wnt5a-Flt1 expression was detected by western blot and IHC. Compared to control group, neonatal rats in LPS group showed higher death rate (1.4% vs 10.1%, p < 0.05) and lower birth weight (6.36 ± 0.48 vs 5.70 ± 0.67, p < 0.01); the villi vessel area and mean diameter in the placenta were significantly reduced in the LPS group (total area %, 16.7% ± 0.6% vs 8.7% ± 0.4%, p < 0.01, n = 9; mean diameter (pixel), 15.6 ± 0.5 vs 12.9 ± 0.3, p < 0.01, n = 9). Placenta Wnt5a-Flt1 expression was upregulated significantly (integrated optical density (IOD) in IHC: Wnt5a, 1667 ± 1204 vs 11,076 ± 4046, p < 0.05; Flt1, 2554 ± 466.2 vs 7998 ± 1613, p < 0.05; western blot: Wnt5a, 0.33 ± 0.05 vs 0.96 ± 0.06, p < 0.05; Flt1, 0.36 ± 0.15 vs 1.08 ± 0.08, p < 0.05). Intrauterine inflammation gave rise to offspring death rate and low birth weight; the mechanism might be disordered placental angiogenesis via Wnt5a-Flt1 activation triggered by inflammation.

Biological interactions between nanomaterials and placental development and function following oral exposure

We summarize the literature involving the deposition of nanomaterials within the placenta following oral exposure and the biological interactions between nanomaterials and placental development and function. The review focuses on the oral exposure of metal and metal oxide engineered nanomaterials (ENMs), carbon-based ENMs, and nanoplastics in animal models, with a minor discussion of intravenous injections. Although the literature suggests that the placenta is an efficient barrier in preventing nanomaterials from reaching the fetus, nanomaterials that accumulate in the placenta may interfere with its development and function. Furthermore, some studies have demonstrated a decrease in placental weight and association with adverse fetal health outcomes following oral exposure to nanomaterials. Since nanomaterials are increasingly used in food, food packaging, and have been discovered in drinking water, the risk for adverse impacts on placental development and functions, with secondary effects on embryo-fetal development, following unintentional maternal ingestion of nanomaterials requires further investigation.

Co-exposure subacute toxicity of silica nanoparticles and lead acetate on cardiovascular system

Background

The harmful effects following the release of nanomaterials into environment are of great concern today.

Purpose

In this study, subacute effect due to co-exposure to low-dose silica nanoparticles (SiNPs) and lead acetate (Pb) on cardiovascular system was detected in Sprague Dawley male rats.

Materials and Methods

Histopathological and ultrastructural changes of heart, aortic arch and abdominal aorta were detected. Blood routine and blood biochemistry examinations were used to show the changes of blood components. The fibrinolytic and plasmin factors, inflammation-related factors and myocardial-related enzyme in serum were analysised by ELISA and Western blot assay.

Results

Histopathological and ultrastructural examination of heart, aortic arch, and abdominal aorta showed that serious damage occurred in co-exposure group (n=6/group). Blood routine examination showed that leukocytosis and thrombocytopenia increased markedly, while changes in the erythrocyte count were not obvious in the co-exposure group. The expression of alanine transaminase (ALT) decreased obviously in co-exposure group, while no significant changes were noted in the expression of aspartate aminotransferase (AST), cholesterol (CHO), triglyceride (TG), high-density lipoprotein-cholesterol (HDL-C), and low-density lipoprotein-cholesterol (LDL-C) in the co-exposure group on blood biochemistry analysis. In addition, data from ELISA analysis showed that the levels of fibrinolytic and plasmin factors, including thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time (APTT), tissue-type plasminogen activator (t-PA), tissue factor pathway inhibitor (TFPI), and antithrombin III (AT III), were decreased, while those of human fibrinogen (FIB) and D-dimer (D2D) increased significantly in the co-exposure group. Moreover, the myocardial-related enzyme in serum, tested by ELISA, and cardiovascular-related protein expression of atrial natriuretic peptide and brain natriuretic peptide, tested by Western blot assay, was increased in the heart. Furthermore, the expression of inflammation factors such as C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) was increased in heart tissue subjected to combined exposure, which was manifested by Western blot assay, while the protein levels of angiotensin II (ANG II) and endothelin 1 were (ET-1) elevated in blood vessels in the co-exposure group.

Conclusion

In conclusion, the major interactions involved in subacute toxicity due to co-exposure to low doses of SiNPs and Pb on cardiovascular system were expected to be additive and synergistic in nature. Co-exposure to SiNPs and Pb could aggravate the cardiovascular toxicity via endothelial damage, hypercoagulation, and cardiac injury in vivo.