Downregulation of argininosuccinate synthase 1 (ASS1) is associated with hypoxia in placental development

Mendelian randomization analysis of blood uric acid and risk of preeclampsia: based on GWAS and eQTL data

BACKGROUND

The causal association between blood uric acid and preeclampsia (Preeclampsia, PE) has not been conclusively established based on the literature reviewed to date. This bi-directional Mendelian randomization study aimed to investigate the bi-directional causal association between blood uric acid concentration and PE at different genetic levels.

METHODS

Pooled data on preeclampsia (sample size = 82,085) and blood uric acid (sample size = 129,405) were conducted based on publicly available genome-wide association analysis (Genome-Wide Association Study, GWAS) on the East Asian populations regarding preeclampsia and blood uric acid, respectively. We assessed blood uric acid and PE associations using two-sample Mendelian randomization (TSMR) analyses based on GWAS pooled statistics using inverse variance weighted (Inverse variance weighted), MR-Egger, and Weighted median (Weighted median) to examine the association between blood uric acid and pre-eclampsia. Causal relationship between blood uric acid and pre-eclampsia.Cochran's Q statistic was used to quantify the heterogeneity of instrumental variables among other methods. Subsequently, we extracted the expression quantitative trait loci (eQCTL, Expression quantitative trait loci) data corresponding to each gene as the instrumental variables using the genes corresponding to the intersecting instrumental variables of the exposure and the outcome in the respective analyses of the forward and backward TSMR respectively, so as to analyze the genetic causality of the genes with the different forward and backward TSMR methods further. Inverse variance weighted (IVW) was used to analyze the genetic causality of genes with different positive and negative outcomes.

RESULTS

Genetically determined blood uric acid level IVW method, ratio (OR) 1.30, 95% confidence interval (CI): [0.6, 2.83], p = 0.51 was not risk associated with PE. In addition according to the inverse MR analysis, we found an OR of 0.99, 95% CI [0.99, 1.0], p = 0.999) for PE on blood uric acid level IVW method and no significant heterogeneity in instrumental variables or level polytropy was found. (ii) Although GWAS data suggested no risk association between PE and uric acid, gene association analysis of eQTL data at blood uric acid levels with PE suggested a risk effect of the TP53INP1 gene for PE (IVW, OR = 11.476, 95% CI 2.511-52.452, p = 1.648 × 10-3) and a protective effect of CTSZ (IVW, OR = 0.011, 95% CI 0.001-0.189, p = 1.804 × 10-3), while a risk effect of ETV7 on hyperuricemia was suggested in a genetic association analysis of PE eQTL data with blood uric acid levels (OR = 1.018, 95% CI 1.007-1.029, p = 1.289 × 10-3).

CONCLUSION

Our MR (Mendelian Randomization) study based on the GWAS database did not support a bidirectional causal effect between blood uric acid levels and PE, whereas MR based on quantitative trait loci suggested that TP53INP1, which affects uric acid levels, has a risk association for PE, whereas CTSZ is protective against preeclampsia. Among the genes affecting PE the ETV7 gene may play a positive role in elevating uric acid levels.

Effects of mineral fibres in an in vitro placental syncytiotrophoblast model

It is known that mineral fibres can be found in placental tissues, but their effect is not known on these tissues. BeWo in vitro model of syncytiotrophoblast, the outer layer of maternal-foetal barrier, is necessary to understand if mineral fibres can alter placental cell turnover and consequently to influence the outcome of pregnancy. We performed in vitro experiments using chrysotile UICC (UICC), chrysotile Valmalenco (VM) and erionite (ERI) to investigate the potential cytotoxic effects of these mineral fibres on BeWo cells. We demonstrated that all fibres are toxic while only UICC fibres caused a DNA damage that the cells were not able to repair through RAD51 activity. In addition, we demonstrated that DNA replication is not altered while cyclin D1 showed a significant decrease in VM and UICC suggesting that the cell cycle is altered in G1 phase. Moreover, UICC increased active form of caspase 3 demonstrating that apoptosis can be induced in BeWo cells. We suggest that although morphological changes are not visible in BeWo cells treated with these mineral fibres, DNA damage can lead to altered placenta physiology that can be seen late when the damage at the foetal tissues has already occurred.

Preeclampsia as a Study Model for Aging: The Klotho Gene Paradigm

Aging and pregnancy are often considered opposites in a woman's biological timeline. Aging is defined by a gradual decline in the functional capabilities of an organism over its lifetime, while pregnancy is characterized by the presence of the transient placenta, which fosters the cellular fitness necessary to support fetal growth. However, in the context of preeclampsia, pregnancy and aging share common hallmarks, including clinical complications, altered cellular phenotypes, and heightened oxidative stress. Furthermore, women with pregnancies complicated by preeclampsia tend to experience age-related disorders earlier than those with healthy pregnancies. Klotho, a gene discovered fortuitously in 1997 by researchers studying aging mechanisms, is primarily expressed in the kidneys but also to a lesser extent in several other tissues, including the placenta. The Klotho protein is a membrane-bound protein that, upon cleavage by ADAM10/17, is released into the circulation as soluble Klotho (sKlotho) where it plays a role in modulating oxidative stress. This review focuses on the involvement of sKlotho in the development of preeclampsia and age-related disorders, as well as the expression of the recently discovered Mytho gene, which has been associated with skeletal muscle atrophy.

miR-155 mediated regulation of PKG1 and its implications on cell invasion, migration, and apoptosis in preeclampsia through NF-κB pathway

BACKGROUND

Preeclampsia (PE) is a severe pregnancy complication characterized by complex molecular interactions. Understanding these interactions is crucial for developing effective therapeutic strategies.

METHODS

This study applies a pharmacometabolomics approach to explore the roles of miR-155 and PKG1 in PE, focusing on the regulatory influence of the NF-κB signaling pathway. Blood metabolomic profiles were analyzed, and bioinformatics tools, IHC staining, Western blot (WB) analysis, and immunofluorescence (IF) localization were employed to determine the expression and function of miR-155 and PKG1. Cell invasion, migration, proliferation, and apoptosis assays were conducted to assess miR-155's modulation of PKG1. Additionally, RT-qPCR and WB analysis elucidated NF-κB-mediated regulation mechanisms.

RESULTS

Our findings indicate significant metabolic alterations associated with miR-155 modulation of PKG1, with NF-κB acting as a critical upstream regulator. The study demonstrates that miR-155 affects cellular functions such as invasion, migration, proliferation, and apoptosis through PKG1 modulation. Furthermore, the NF-κB signaling pathway regulates miR-155 expression, contributing to the pathological processes of PE.

CONCLUSION

This study provides a proof of concept for using pharmacometabolomics to understand the molecular mechanisms of PE, suggesting new therapeutic targets and advancing personalized medicine approaches. These insights highlight the potential of pharmacometabolomics to complement genomic and transcriptional data in disease characterization and treatment strategies, offering new avenues for therapeutic intervention in PE.

The Role of Xanthine Oxidase in Pregnancy Complications: A Systematic Review

Xanthine oxidoreductase (XOR) is an enzyme involved in the oxidation of hypoxanthine and xanthine to uric acid. XOR has two isoforms: xanthine dehydrogenase and xanthine oxidase (XO). XO plays a major role in oxidative stress, causing the formation of reactive oxygen species. In the present study, we aimed to summarize the evidence on the association between XO and pregnancy complications. The PRISMA checklist guided the reporting of the data. We conducted systematic searches in the PubMed and Web of Science databases to identify all human studies investigating XO in pregnancy diseases up to June 2024. A total of 195 references have been identified and 14 studies were included. Most studies focused on women with PE and GD. Overall, all the included studies found a statistically significant increase in maternal, placental, and/or fetal XO levels, activity, or tissue expression in women with pregnancy complications, compared to those with uncomplicated pregnancies. Although promising, the quality and dimension of the included studies do not allow for a definitive answer to the question of whether XO may play a crucial role in pregnancy complications. Future studies are warranted to confirm if XO could represent a prognostic and therapeutic marker in pregnancy complications and their impact on long-term maternal and offspring cardiovascular health.

Understanding the intersection between placental development and cancer: Lessons from the tumor suppressor BAP1

The placenta, a pivotal organ in mammalian reproduction, allows nutrient exchange and hormonal signaling between the mother and the developing fetus. Understanding its molecular intricacies is essential for deciphering normal embryonic development and pathological conditions such as tumorigenesis. Here, we explore the multifaceted role of the tumor suppressor BRCA1-associated protein 1 (BAP1) in cancer and placentation. Initially recognized for its tumor-suppressive properties, BAP1 has emerged as a key regulator at the intersection of tumorigenesis and placental development. BAP1 influences crucial cellular processes such as cell death, proliferation, metabolism, and response to hypoxic conditions. By integrating insights from tumor and developmental biology, we illuminate the complex molecular pathways orchestrated by BAP1. This perspective highlights BAP1's significant impact on both cancer and placental development, and suggests novel therapeutic strategies that could improve outcomes for pregnancy disorders and cancer.

Circulating miRNAs and Preeclampsia: From Implantation to Epigenetics

In this review, we comprehensively present the literature on circulating microRNAs (miRNAs) associated with preeclampsia, a pregnancy-specific disease considered the primary reason for maternal and fetal mortality and morbidity. miRNAs are single-stranded non-coding RNAs, 20-24 nt long, which control mRNA expression. Changes in miRNA expression can induce a variation in the relative mRNA level and influence cellular homeostasis, and the strong presence of miRNAs in all body fluids has made them useful biomarkers of several diseases. Preeclampsia is a multifactorial disease, but the etiopathogenesis remains unclear. The functions of trophoblasts, including differentiation, proliferation, migration, invasion and apoptosis, are essential for a successful pregnancy. During the early stages of placental development, trophoblasts are strictly regulated by several molecular pathways; however, an imbalance in these molecular pathways can lead to severe placental lesions and pregnancy complications. We then discuss the role of miRNAs in trophoblast invasion and in the pathogenesis, diagnosis and prediction of preeclampsia. We also discuss the potential role of miRNAs from an epigenetic perspective with possible future therapeutic implications.

Sodium Nitrite Attenuates Reduced Activity of Vascular Matrix Metalloproteinase-2 and Vascular Hyper-Reactivity and Increased Systolic Blood Pressure Induced by the Placental Ischemia Model of Preeclampsia in Anesthetized Rats

Preeclampsia is a maternal hypertension disorder associated with vascular dysfunction and fetal and placental growth restrictions. Placental ischemia is suggested as the primary trigger of preeclampsia-associated impairments of both endothelium-derived nitric oxide (NO) and the vascular activity of extracellular matrix metalloproteinase-2 (MMP-2). Reduced uteroplacental perfusion pressure (RUPP) is a placental ischemia model of preeclampsia. Reduction of sodium nitrite to NO may occur during ischemic conditions. However, sodium nitrite effects in the RUPP model of preeclampsia have not yet been investigated. Pregnant rats were divided into four groups: normotensive pregnant rats (Norm-Preg), pregnant rats treated with sodium nitrite (Preg + Nitrite), preeclamptic rats (RUPP), and preeclamptic rats treated with sodium nitrite (RUPP + Nitrite). Maternal blood pressure and fetal and placental parameters were recorded. Vascular function, circulating NO metabolites, and the gelatinolytic activity of vascular MMP-2 were also examined. Sodium nitrite attenuates increased blood pressure, prevents fetal and placental weight loss, counteracts vascular hyper-reactivity, and partially restores NO metabolites and MMP-2 activity. In conclusion, sodium nitrite reduction to NO may occur during RUPP-induced placental ischemia, thereby attenuating increased blood pressure, fetal and placental growth restriction, and vascular hyper-reactivity associated with preeclampsia and possibly restoring NO and MMP-2 activity, which underlie the blood pressure-lowering effects.